spi: Restore delays for non-GPIO chip select

SPI controller with integrated chip select handling still need to adhere
to SPI device's CS setup, hold and inactive delays. For controller
without set_cs_timing spi core shall handle the delays to avoid
duplicated delay handling in each controller driver.
Fixes a regression for the out of tree SPI controller and SPI HID
transport on Apple M1/M1 Pro/Max notebooks.

Fixes: 4d8ff6b0991d ("spi: Add multi-cs memories support in SPI core")
Signed-off-by: Janne Grunau <j@jannau.net>
Link: https://msgid.link/r/20240311-spi-cs-delays-regression-v1-1-0075020a90b2@jannau.net
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Introduce SPI_INVALID_CS and is_valid_cs()

The SPI core inconsistently uses the marker value for unused chip select
pin. Define a constant (with appropriate type) and introduce is_valid_cs()
helper function to avoid spreading this inconsistency in the future.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://msgid.link/r/20240307150256.3789138-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Consistently use BIT for cs_index_mask

Some of the parts related to the chip select are using BIT() macro
the rest are using plain numbers. Unify all of them to use BIT().

While at it, make the (repetitive) comment clearer when assigning
cs_index_mask during SPI target device enumeration.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://msgid.link/r/20240307150256.3789138-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Exctract spi_dev_check_cs() helper

It seems a few functions implement the similar for-loop to validate
chip select pins for uniqueness. Let's deduplicate that code in order
to have a single place of that for better maintenance.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://msgid.link/r/20240306160114.3471398-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Exctract spi_set_all_cs_unused() helper

It seems a few functions implement the similar for-loop to mark all
chip select pins unused. Let's deduplicate that code in order to have
a single place of that for better maintenance.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://msgid.link/r/20240306160114.3471398-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: move splitting transfers to spi_optimize_message()

Splitting transfers is an expensive operation so we can potentially
optimize it by doing it only once per optimization of the message
instead of repeating each time the message is transferred.

The transfer splitting functions are currently the only user of
spi_res_alloc() so spi_res_release() can be safely moved at this time
from spi_finalize_current_message() to spi_unoptimize_message().

The doc comments of the public functions for splitting transfers are
also updated so that callers will know when it is safe to call them
to ensure proper resource management.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://msgid.link/r/20240219-mainline-spi-precook-message-v2-2-4a762c6701b9@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add spi_optimize_message() APIs

This adds a new spi_optimize_message() function that can be used to
optimize SPI messages that are used more than once. Peripheral drivers
that use the same message multiple times can use this API to perform SPI
message validation and controller-specific optimizations once and then
reuse the message while avoiding the overhead of revalidating the
message on each spi_(a)sync() call.

Internally, the SPI core will also call this function for each message
if the peripheral driver did not explicitly call it. This is done to so
that controller drivers don't have to have multiple code paths for
optimized and non-optimized messages.

A hook is provided for controller drivers to perform controller-specific
optimizations.

Suggested-by: Martin Sperl <kernel@martin.sperl.org>
Link: https://lore.kernel.org/linux-spi/39DEC004-10A1-47EF-9D77-276188D2580C@martin.sperl.org/
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://msgid.link/r/20240219-mainline-spi-precook-message-v2-1-4a762c6701b9@baylibre.com
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Drop compat layer from renaming "master" to "controller"

Now that all in-tree users followed the rename, the compat stuff can go
away. This completes the renaming started with commit 8caab75fd2c2
("spi: Generalize SPI "master" to "controller"")

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/ad1d949325b61a4682e8d6ecf9d05da751e6a99f.1707324794.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: drop gpf arg from __spi_split_transfer_maxsize()

The __spi_split_transfer_maxsize() function has a gpf argument to allow
callers to specify the type of memory allocation that needs to be used.
However, this function only allocates struct spi_transfer and is not
intended to be used from atomic contexts so this type should always be
GFP_KERNEL, so we can just drop the argument.

Some callers of these functions also passed GFP_DMA, but since only
struct spi_transfer is allocated and not any tx/rx buffers, this is
not actually necessary and is removed in this commit.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240206200648.1782234-1-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: move split xfers for CS_WORD emulation

This moves splitting transfers for CS_WORD software emulation to the
same place where we split transfers for controller-specific reasons.

This fixes a few subtle bugs.

The calculation for maxsize was wrong for bit sizes between 17 and 24.
This is fixed by making use of spi_split_transfers_maxwords() which
already has the correct calculation.

Also, since this indirectly calls spi_res_alloc(), to avoid leaking
resources, spi_finalize_current_message() would need to be called
on all error paths in __spi_validate() and callers of __spi_validate()
would need to do the same. This is fixed by moving the call to
__spi_pump_transfer_message() where it is already splitting transfers
for other reasons and correctly releases resources in the subsequent
error paths.

Fixes: cbaa62e0094a ("spi: add software implementation for SPI_CS_WORD")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240126212358.3916280-2-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: avoid double validation in __spi_sync()

The __spi_sync() function calls __spi_validate() early in the function.
Later, it can call spi_async_locked() which calls __spi_validate()
again. __spi_validate() is an expensive function, so we can improve
performance measurably by avoiding calling it twice.

Instead of calling spi_async_locked(), we can call __spi_async() with
the spin lock held.

spi_async_locked() is removed since there are no more callers.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://msgid.link/r/20240125234732.3530278-2-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: consolidate setting message->spi

Previously, __spi_sync() and __spi_async() set message->spi to the spi
device independently after calling __spi_validate(). __spi_validate()
also would conditionally set this if it needed to split the message
since it wasn't set yet.

Since both __spi_sync() and __spi_async() call __spi_validate(), we can
consolidate this into only setting message->spi once (unconditionally)
in __spi_validate(). This will also save any future callers of
__spi_validate() from also needing to set message->spi.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://msgid.link/r/20240123214946.2616786-1-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: make spi_bus_type const

Now that the driver core can properly handle constant struct bus_type,
move the spi_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Mark Brown <broonie@kernel.org>
Cc: <linux-spi@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://msgid.link/r/2024010549-erasure-swoop-1cc6@gregkh
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fix finalize message on error return

In __spi_pump_transfer_message(), the message was not finalized in the
first error return as it is in the other error return paths. Not
finalizing the message could cause anything waiting on the message to
complete to hang forever.

This adds the missing call to spi_finalize_current_message().

Fixes: ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://msgid.link/r/20240125205312.3458541-2-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add multi-cs memories support in SPI core

AMD-Xilinx GQSPI controller has two advanced mode that allows the
controller to consider two flashes as one single device.

One of these two mode is the parallel mode in which each byte of data is
stored in both devices, the even bits in the lower flash & the odd bits in
the upper flash. The byte split is automatically handled by the QSPI
controller.

The other mode is the stacked mode in which both the flashes share the
same SPI bus but each of the device contain half of the data. In this mode,
the controller does not follow CS requests but instead internally wires the
two CS levels with the value of the most significant address bit.

For supporting both these modes SPI core need to be updated for providing
multiple CS for a single SPI device.

For adding multi CS support the SPI device need to be aware of all the CS
values. So, the "chip_select" member in the spi_device structure is now an
array that holds all the CS values.

spi_device structure now has a "cs_index_mask" member. This acts as an
index to the chip_select array. If nth bit of spi->cs_index_mask is set
then the driver would assert spi->chip_select[n].

In parallel mode all the chip selects are asserted/de-asserted
simultaneously and each byte of data is stored in both devices, the even
bits in one, the odd bits in the other. The split is automatically handled
by the GQSPI controller. The GQSPI controller supports a maximum of two
flashes connected in parallel mode. A SPI_CONTROLLER_MULTI_CS flag bit is
added in the spi controller flags, through ctlr->flags the spi core
will make sure that the controller is capable of handling multiple chip
selects at once.

For supporting multiple CS via GPIO the cs_gpiod member of the spi_device
structure is now an array that holds the gpio descriptor for each
chipselect.

CS GPIO is not tested on our hardware, but it has been tested by @Stefan
https://lore.kernel.org/all/005001da1efc$619ad5a0$24d080e0$@opensource.cirrus.com/

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
Tested-by: Stefan Binding <sbinding@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20231125092137.2948-4-amit.kumar-mahapatra@amd.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: introduce SPI_TRANS_FAIL_IO for error reporting

The default message transfer implementation - spi_transfer_one_message -
invokes the specific device driver's transfer_one(), then waits for
completion. However, there is no mechanism for the device driver to
report failure in the middle of the transfer.

Introduce SPI_TRANS_FAIL_IO for drivers to report transfer failure.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/4b420dac528e60f122adde16851da88e4798c1ea.1701274975.git.namcao@linutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix null dereference on suspend

A race condition exists where a synchronous (noqueue) transfer can be
active during a system suspend. This can cause a null pointer
dereference exception to occur when the system resumes.

Example order of events leading to the exception:
1. spi_sync() calls __spi_transfer_message_noqueue() which sets
ctlr->cur_msg
2. Spi transfer begins via spi_transfer_one_message()
3. System is suspended interrupting the transfer context
4. System is resumed
6. spi_controller_resume() calls spi_start_queue() which resets cur_msg
to NULL
7. Spi transfer context resumes and spi_finalize_current_message() is
called which dereferences cur_msg (which is now NULL)

Wait for synchronous transfers to complete before suspending by
acquiring the bus mutex and setting/checking a suspend flag.

Signed-off-by: Mark Hasemeyer <markhas@chromium.org>
Link: https://lore.kernel.org/r/20231107144743.v1.1.I7987f05f61901f567f7661763646cb7d7919b528@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@kernel.org

spi: Export acpi_spi_find_controller_by_adev()

Export acpi_spi_find_controller_by_adev() so that ACPI glue code which
wants to dynamically create a spi_device using acpi_spi_device_alloc() or
spi_new_device() on a controller, to which the code does not already have
a reference, can find the controller.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20231014205314.59333-2-hdegoede@redhat.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Drop warning from spi_stop_queue()

Both callers of spi_stop_queue() (i.e. spi_destroy_queue() and
spi_controller_suspend()) already emit an error message if
spi_stop_queue() fails. Another warning in this case isn't helpful, so
drop it.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230916161235.1050176-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use BITS_TO_BYTES()

BITS_TO_BYTES() is the existing macro which takes care about full
bytes that may fully hold the given amount of bits. Use it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230714091748.89681-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Kill spi_add_device_locked()

Now, spi_add_device_locked() has just a line on top of __spi_add_device().
Besides that, it has a single caller. So, just kill it and embed its parts
into the caller.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230714091748.89681-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove code duplication in spi_add_device*()

The commit 0c79378c0199 ("spi: add ancillary device support")
added a dozen of duplicating lines of code. We may move them
to the __spi_add_device(). Note, that the code may be called
under the mutex.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20230714091748.89681-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix spelling typos and acronyms capitalization

Fix
- spelling typos
- capitalization of acronyms
in the comments.

While at it, fix the multi-line comment style.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-16-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Rename SPI_MASTER_GPIO_SS to SPI_CONTROLLER_GPIO_SS

Rename SPI_MASTER_GPIO_SS to SPI_CONTROLLER_GPIO_SS and
convert the users to SPI_CONTROLLER_GPIO_SS to follow
the new naming shema.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-14-andriy.shevchenko@linux.intel.com
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Sort headers alphabetically

Sorting headers alphabetically helps locating duplicates, and
make it easier to figure out where to insert new headers.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-8-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use sysfs_emit() to instead of s*printf()

Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the
value to be returned to user space.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-7-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Replace if-else-if by bitops and multiplications

Instead of if-else-if, simply call roundup_pow_of_two(BITS_PER_BYTES()).
Note, there is no division assumed as compiler may optimize it away.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Drop duplicate IDR allocation code in spi_register_controller()

Refactor spi_register_controller() to drop duplicate IDR allocation.
Instead of if-else-if branching use two sequential if:s, which allows
to re-use the logic of IDR allocation in all cases.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove unneeded OF node NULL checks

In the couple of places the NULL check of OF node is implied by the call
that takes it as a parameter. Drop the respective duplicate checks.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

of: Rename of_modalias_node()

This helper does not produce a real modalias, but tries to get the
"product" compatible part of the "vendor,product" compatibles only. It
is far from creating a purely useful modalias string and does not seem
to be used like that directly anyway, so let's try to give this helper a
more meaningful name before moving there a real modalias helper (already
existing under of/device.c).

Also update the various documentations to refer to the strings as
"aliases" rather than "modaliases" which has a real meaning in the Linux
kernel.

There is no functional change.

Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Wolfram Sang <wsa@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Sebastian Reichel <sre@kernel.org>
Link: https://lore.kernel.org/r/20230404172148.82422-9-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: remove struct module * setting from struct class

There is no need to manually set the owner of a struct class, as the
registering function does it automatically, so remove all of the
explicit settings from various drivers that did so as it is unneeded.

This allows us to remove this pointer entirely from this structure going
forward.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313181843.1207845-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: core: add spi_split_transfers_maxwords

Add spi_split_transfers_maxwords() function that splits
spi_transfers transparently into multiple transfers
that are below a given number of SPI words.

This function reuses most of its code from
spi_split_transfers_maxsize() and for transfers with
eight or less bits per word actually behaves the same.

Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
Link: https://lore.kernel.org/r/20230310092053.1006459-1-l.goehrs@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix cocci warnings

cocci reported warning: !A || A && B is equivalent to !A || B. This fix
simplified the condition check to !A || B.

Fixes: 76a85704cb91 ("spi: spi-mem: Allow controller supporting mem_ops without exec_op")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202303010051.HrHWSr9y-lkp@intel.com/

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Link: https://lore.kernel.org/r/20230307012004.414502-1-william.zhang@broadcom.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Propagate firmware node

Propagate firmware node by using a specific API call, i.e. device_set_node().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230306182913.87231-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Replace spi_pcpu_stats_totalize() macro by a C function

spi_pcpu_stats_totalize() is a rather large macro, and is instantiated
28 times, causing a large amount of duplication in the amount of
generated code.

Reduce the duplication by replacing spi_pcpu_stats_totalize() by a real
C function, and absorb all other common code from
spi_statistics_##name##_show(). As (a) the old "field" parameter was
the name of a structure member, which cannot be passed to a function,
and (b) passing a pointer to the member is also not an option, due to
the loop over all possible CPUs, the "field" parameter is replaced by an
"offset" parameter, pointing to a location within the structure.

This reduces kernel size by ca. 4 KiB (on arm32 and arm64).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/cb7690d9d04c06eec23dbb98fbb5444082125cff.1677594432.git.geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>

treewide: Fix probing of devices in DT overlays

When loading a DT overlay that creates a device, the device is not
probed, unless the DT overlay is unloaded and reloaded again.

After the recent refactoring to improve fw_devlink, it no longer depends
on the "compatible" property to identify which device tree nodes will
become struct devices. fw_devlink now picks up dangling consumers
(consumers pointing to descendent device tree nodes of a device that
aren't converted to child devices) when a device is successfully bound
to a driver. See __fw_devlink_pickup_dangling_consumers().

However, during DT overlay, a device's device tree node can have
sub-nodes added/removed without unbinding/rebinding the driver. This
difference in behavior between the normal device instantiation and
probing flow vs. the DT overlay flow has a bunch of implications that
are pointed out elsewhere[1]. One of them is that the fw_devlink logic
to pick up dangling consumers is never exercised.

This patch solves the fw_devlink issue by marking all DT nodes added by
DT overlays with FWNODE_FLAG_NOT_DEVICE (fwnode that won't become
device), and by clearing the flag when a struct device is actually
created for the DT node. This way, fw_devlink knows not to have
consumers waiting on these newly added DT nodes, and to propagate the
dependency to an ancestor DT node that has the corresponding struct
device.

Based on a patch by Saravana Kannan, which covered only platform and spi
devices.

[1] https://lore.kernel.org/r/CAGETcx_bkuFaLCiPrAWCPQz+w79ccDp6=9e881qmK=vx3hBMyg@mail.gmail.com

Fixes: 4a032827daa89350 ("of: property: Simplify of_link_to_phandle()")
Link: https://lore.kernel.org/r/CAGETcx_+rhHvaC_HJXGrr5_WAd2+k5f=rWYnkCZ6z5bGX-wj4w@mail.gmail.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C
Acked-by: Shawn Guo <shawnguo@kernel.org>
Acked-by: Saravana Kannan <saravanak@google.com>
Tested-by: Ivan Bornyakov <i.bornyakov@metrotek.ru>
Link: https://lore.kernel.org/r/e1fa546682ea4c8474ff997ab6244c5e11b6f8bc.1680182615.git.geert+renesas@glider.be
Signed-off-by: Rob Herring <robh@kernel.org>

driver core: make struct bus_type.uevent() take a const *

The uevent() callback in struct bus_type should not be modifying the
device that is passed into it, so mark it as a const * and propagate the
function signature changes out into all relevant subsystems that use
this callback.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-16-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: Reorder fields in 'struct spi_transfer'

Group some variables based on their sizes to reduce hole and avoid padding.
On x86_64, this shrinks the size from 144 to 128 bytes.

Turn 'timestamped' into a bitfield so that it can be easily merged with
some other bifields and move 'error'.

This should have no real impact on memory allocation because 'struct
spi_transfer' is mostly used on stack, but it can save a few cycles
when the structure is initialized or copied.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/93a051da85a895bc6003aedfb00a13e1c2fc6338.1676370870.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-mem: Allow controller supporting mem_ops without exec_op

Currently exec_op is always required if controller driver provides
mem_ops. But some controller such as bcm63xx-hsspi may only need to
implement other operation like supports_op and use the default
execution operation. This patch removes this restriction.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Link: https://lore.kernel.org/r/20230209200246.141520-13-william.zhang@broadcom.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: export spi_transfer_cs_change_delay_exec function

For SPI controller that implements transfer_one_message, it needs to
insert the delay that required by cs change event between the transfers.
Add a wrapper for the local function _spi_transfer_cs_change_delay_exec
and export it for SPI controller driver to use.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Link: https://lore.kernel.org/r/20230209200246.141520-9-william.zhang@broadcom.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add APIs in spi core to set/get spi->chip_select and spi->cs_gpiod

Supporting multi-cs in spi core and spi controller drivers would require
the chip_select & cs_gpiod members of struct spi_device to be an array.
But changing the type of these members to array would break the spi driver
functionality. To make the transition smoother introduced four new APIs to
get/set the spi->chip_select & spi->cs_gpiod and replaced all
spi->chip_select and spi->cs_gpiod references in spi core with the API
calls.
While adding multi-cs support in further patches the chip_select & cs_gpiod
members of the spi_device structure would be converted to arrays & the
"idx" parameter of the APIs would be used as array index i.e.,
spi->chip_select[idx] & spi->cs_gpiod[idx] respectively.

Suggested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20230119185342.2093323-2-amit.kumar-mahapatra@amd.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Parse hold/inactive CS delay values from the DT

Now that we support parsing the setup time from the Device Tree, we can
also easily support the remaining hold and inactive time delay values.

Signed-off-by: Janne Grunau <j@jannau.net>
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20230113102309.18308-4-marcan@marcan.st
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use a 32-bit DT property for spi-cs-setup-delay-ns

65us is not a reasonable maximum for this property, as some devices
might need a much longer setup time (e.g. those driven by firmware on
the other end). Plus, device tree property values are in 32-bit cells
and smaller widths should not be used without good reason.

Also move the logic to a helper function, since this will later be used
to parse other CS delay properties too.

Fixes: 33a2fde5f77b ("spi: Introduce spi-cs-setup-ns property")
Signed-off-by: Janne Grunau <j@jannau.net>
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20230113102309.18308-2-marcan@marcan.st
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Rename spi-cs-setup-ns property to spi-cs-setup-delay-ns

As mentioned in the corresponding DT binding commit, the naming scheme
for delay properties includes "delay" in the name, so let's keep that
consistent.

Fixes: 33a2fde5f77b ("spi: Introduce spi-cs-setup-ns property")
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20230104093631.15611-3-marcan@marcan.st
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Reintroduce spi_set_cs_timing()

commit 4ccf359849ce ("spi: remove spi_set_cs_timing()"), removed the
method as noboby used it. Nobody used it probably because some SPI
controllers use some default large cs-setup time that covers the usual
cs-setup time required by the spi devices. There are though SPI controllers
that have a smaller granularity for the cs-setup time and their default
value can't fulfill the spi device requirements. That's the case for the
at91 QSPI IPs where the default cs-setup time is half of the QSPI clock
period. This was observed when using an sst26vf064b SPI NOR flash which
needs a spi-cs-setup-ns = <7>; in order to be operated close to its maximum
104 MHz frequency.

Call spi_set_cs_timing() in spi_setup() just before calling spi_set_cs(),
as the latter needs the CS timings already set.
If spi->controller->set_cs_timing is not set, the method will return 0.
There's no functional impact expected for the existing drivers. Even if the
spi-mt65xx.c and spi-tegra114.c drivers set the set_cs_timing method,
there's no user for them as of now. The only tested user of this support
will be a SPI NOR flash that comunicates with the Atmel QSPI controller for
which the support follows in the next patches.

One will notice that this support is a bit different from the one that was
removed in commit 4ccf359849ce ("spi: remove spi_set_cs_timing()"),
because this patch adapts to the changes done after the removal: the move
of the cs delays to the spi device, the retirement of the lelgacy GPIO
handling. The mutex handling was removed from spi_set_cs_timing() because
we now always call spi_set_cs_timing() in spi_setup(), which already
handles the spi->controller->io_mutex, so use the mutex handling from
spi_setup().

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20221117105249.115649-4-tudor.ambarus@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Introduce spi-cs-setup-ns property

SPI NOR flashes have specific cs-setup time requirements without which
they can't work at frequencies close to their maximum supported frequency,
as they miss the first bits of the instruction command. Unrecognized
commands are ignored, thus the flash will be unresponsive. Introduce the
spi-cs-setup-ns property to allow spi devices to specify their cs setup
time.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20221117105249.115649-3-tudor.ambarus@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: introduce new helpers with using modern naming

For using modern names host/target to instead of all the legacy names,
I think it takes 3 steps:
- step1: introduce new helpers with modern naming.
- step2: switch to use these new helpers in all drivers.
- step3: remove all legacy helpers and update all legacy names.

This patch is for step1, it introduces new helpers with host/target
naming for drivers using.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221011092204.950288-1-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove the obsolte u64_stats_fetch_*_irq() users.

Now that the 32bit UP oddity is gone and 32bit uses always a sequence
count, there is no need for the fetch_irq() variants anymore.

Convert to the regular interface.

Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221026122951.331638-1-bigeasy@linutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Introduce spi_get_device_match_data() helper

The proposed spi_get_device_match_data() helper is for retrieving
a driver data associated with the ID in an ID table. First, it tries
to get driver data of the device enumerated by firmware interface
(usually Device Tree or ACPI). If none is found it falls back to
the SPI ID table matching.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221020195421.10482-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Ensure that sg_table won't be used after being freed

SPI code checks for non-zero sgt->orig_nents to determine if the buffer
has been DMA-mapped. Ensure that sg_table is really zeroed after free to
avoid potential NULL pointer dereference if the given SPI xfer object is
reused again without being DMA-mapped.

Fixes: 0c17ba73c08f ("spi: Fix cache corruption due to DMA/PIO overlap")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20220930113408.19720-1-m.szyprowski@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Split transfers larger than max size

A couple of drivers call spi_split_transfers_maxsize() from their
->prepare_message() callbacks to split transfers which are too big for
them to handle. Add support in the core to do this based on
->max_transfer_size() to avoid code duplication.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20220927112117.77599-4-vincent.whitchurch@axis.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix cache corruption due to DMA/PIO overlap

The SPI core DMA mapping support performs cache management once for the
entire message and not between transfers, and this leads to cache
corruption if a message has two or more RX transfers with both
transfers targeting the same cache line, and the controller driver
decides to handle one using DMA and the other using PIO (for example,
because one is much larger than the other).

Fix it by syncing before/after the actual transfers. This also means
that we can skip the sync during the map/unmap of the message.

Fixes: 99adef310f68 ("spi: Provide core support for DMA mapping transfers")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20220927112117.77599-3-vincent.whitchurch@axis.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Save current RX and TX DMA devices

Save the current RX and TX DMA devices to avoid having to duplicate the
logic to pick them, since we'll need access to them in some more
functions to fix a bug in the cache handling.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20220927112117.77599-2-vincent.whitchurch@axis.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add capability to perform some transfer with chipselect off

Some components require a few clock cycles with chipselect off before
or/and after the data transfer done with CS on.

Typically IDT 801034 QUAD PCM CODEC datasheet states "Note *: CCLK
should have one cycle before CS goes low, and two cycles after
CS goes high".

The cycles "before" are implicitely provided by all previous activity
on the SPI bus. But the cycles "after" must be provided in order to
terminate the SPI transfer.

In order to use that kind of component, add a cs_off flag to
spi_transfer struct. When this flag is set, the transfer is performed
with chipselect off. This allows consummer to add a dummy transfer
at the end of the transfer list which is performed with chipselect
OFF, providing the required additional clock cycles.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/434165c46f06d802690208a11e7ea2500e8da4c7.1662558898.git.christophe.leroy@csgroup.eu
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: move from strlcpy with unused retval to strscpy

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20220818210107.7373-1-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>

ACPI: Drop parent field from struct acpi_device

The parent field in struct acpi_device is, in fact, redundant,
because the dev.parent field in it effectively points to the same
object and it is used by the driver core.

Accordingly, the parent field can be dropped from struct acpi_device
and for this purpose define acpi_dev_parent() to retrieve a parent
struct acpi_device pointer from the dev.parent field in struct
acpi_device. Next, update all of the users of the parent field
in struct acpi_device to use acpi_dev_parent() instead of it and
drop it.

While at it, drop the ACPI_IS_ROOT_DEVICE() macro that is only used
in one place in a confusing way.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Punit Agrawal <punit.agrawal@bytedance.com>

spi: spi: Fix queue hang if previous transfer failed

The queue worker always needs to be kicked one final time after a transfer
is done in order to transition to idle (ctlr->busy = false).

Commit 69fa95905d40 ("spi: Ensure the io_mutex is held until
spi_finalize_current_message()") moved this code into
__spi_pump_messages(), but it was executed only if the transfer was
successful. This condition check causes ctlr-busy to stay true in case of
a failed transfer.
This in turn causes that no new work is ever scheduled to the work queue.

Fixes: 69fa95905d40 ("spi: Ensure the io_mutex is held until spi_finalize_current_message()")
Reported-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220901123630.1098433-1-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: mux: Fix mux interaction with fast path optimisations

The spi-mux driver is rather too clever and attempts to resubmit any
message that is submitted to it to the parent controller with some
adjusted callbacks. This does not play at all nicely with the fast
path which now sets flags on the message indicating that it's being
handled through the fast path, we see async messages flagged as being on
the fast path. Ideally the spi-mux code would duplicate the message but
that's rather invasive and a bit fragile in that it relies on the mux
knowing which fields in the message to copy. Instead teach the core
that there are controllers which can't cope with the fast path and have
the mux flag itself as being such a controller, ensuring that messages
going via the mux don't get partially handled via the fast path.

This will reduce the performance of any spi-mux connected device since
we'll now always use the thread for both the actual controller and the
mux controller instead of just the actual controller but given that we
were always hitting the slow path anyway it's hopefully not too much of
an additional cost and it allows us to keep the fast path.

Fixes: ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync")
Reported-by: Casper Andersson <casper.casan@gmail.com>
Tested-by: Casper Andersson <casper.casan@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220901120732.49245-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi.c: Add missing __percpu annotations in users of spi_statistics

Fixes sparse warnings of this kind:
drivers/spi/spi.c:117:16: sparse: expected struct spi_statistics *
drivers/spi/spi.c:117:16: sparse: got struct spi_statistics [noderef]
__percpu *[assigned] pcpu_stats

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220805084458.1602277-1-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use device_find_any_child() instead of custom approach

We have already a helper to get the first child device, use it and
drop custom approach.

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220610120219.18988-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: Fix simplification of devm_spi_register_controller

This reverts commit 59ebbe40fb51 ("spi: simplify
devm_spi_register_controller").

If devm_add_action() fails in devm_add_action_or_reset(),
devm_spi_unregister() will be called, it decreases the
refcount of 'ctlr->dev' to 0, then it will cause uaf in
the drivers that calling spi_put_controller() in error path.

Fixes: 59ebbe40fb51 ("spi: simplify devm_spi_register_controller")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20220712135504.1055688-1-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: remove duplicate parameters check in acpi_spi_add_resource()

The acpi_spi_add_resource() is never called with ctrl == NULL and
index == -1. The only caller already performs the check. Hence
remove the duplication from the acpi_spi_add_resource().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220709000709.35622-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: propagate error code to the caller of acpi_spi_device_alloc()

Since acpi_spi_device_alloc() has been designed to return an error
pointer we may now properly propagate error codes to the caller of
it. It helps debugging a lot.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220709000709.35622-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Return deferred probe error when controller isn't yet available

If the controller is not available, it might be in the future and
we would like to re-probe the peripheral again. For that purpose
return deferred probe.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215993
Fixes: 87e59b36e5e2 ("spi: Support selection of the index of the ACPI Spi Resource before alloc")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220709212956.25530-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi.c: Remove redundant else block

Reported-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220629142519.3985486-4-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi.c: Fix comment style

Capitalize first word in comment where appropriate and add
parentheses to function names.

Reported-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220629142519.3985486-3-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi.c: White-space fix in __spi_pump_messages()

Reported-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220629142519.3985486-2-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: opportunistically skip ctlr->cur_msg_completion

There are only a few drivers that do not call
spi_finalize_current_message() in the context of transfer_one_message(),
and even for those cases the completion ctlr->cur_msg_completion is not
needed always. The calls to complete() and wait_for_completion() each
take a spin-lock, which is costly. This patch makes it possible to avoid
those calls in the big majority of cases, by introducing two flags that
with the help of ordering via barriers can avoid using the completion
safely. In case of a race with the context calling
spi_finalize_current_message(), the scheme errs on the safe side and takes
the completion.
The impact of this patch is worth the effort: On a i.MX8MM SoC, the time
the SPI bus is idle between two consecutive calls to spi_sync(), is
reduced from 19.6us to 16.8us... roughly 15%.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-12-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Ensure the io_mutex is held until spi_finalize_current_message()

This patch introduces a completion that is completed in
spi_finalize_current_message() and waited for in
__spi_pump_transfer_message(). This way all manipulation of ctlr->cur_msg
is done with the io_mutex held and strictly ordered:
__spi_pump_transfer_message() will not return until
spi_finalize_current_message() is done using ctlr->cur_msg, and its
calling context is only touching ctlr->cur_msg after returning.
Due to this, we can safely drop the spin-locks around ctlr->cur_msg.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-11-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Set ctlr->cur_msg also in the sync transfer case

Some drivers rely on this to point to the currently processed message, so
set this here also.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-10-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove unneeded READ_ONCE for ctlr->busy flag

Now this flag is written entirely in the mutex, so no need for READ_ONCE

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-9-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove the now unused ctlr->idling flag

The ctlr->idling flag is never checked now, so we don't need to set it
either.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-8-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove check for idling in __spi_pump_messages()

Since the whole idling transition is locked by the io_mutex now, there is
no need to check this flag anymore.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-7-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove check for controller idling in spi sync path

Now that the idling flag is wholly behind the io_mutex, this broken piece
of code can be safely removed.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-6-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: __spi_pump_messages: Consolidate spin_unlocks to goto target

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-5-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Lock controller idling transition inside the io_mutex

This way, the spi sync path does not need to deal with the idling
transition.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-4-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Don't use the message queue if possible in spi_sync

The interaction with the controller message queue and its corresponding
auxiliary flags and variables requires the use of the queue_lock which is
costly. Since spi_sync will transfer the complete message anyway, and not
return until it is finished, there is no need to put the message into the
queue if the queue is empty. This can save a lot of overhead.

As an example of how significant this is, when using the MCP2518FD SPI CAN
controller on a i.MX8MM SoC, the time during which the interrupt line
stays active (during 3 relatively short spi_sync messages), is reduced
from 98us to 72us by this patch.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-3-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Move ctlr->cur_msg_prepared to struct spi_message

This enables the possibility to transfer a message that is not at the
current tip of the async message queue.
This is in preparation of the next patch(es) which enable spi_sync messages
to skip the queue altogether.

Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-2-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: Fix error code in spi_register_controller()

Return -ENOMEM if the allocation fails. Don't return success.

Fixes: 6598b91b5ac3 ("spi: spi.c: Convert statistics to per-cpu u64_stats_t")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/Yqh6bdNYO2XNhPBa@kili
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix per-cpu stats access on 32 bit systems

On 32 bit systems, the following kernel BUG is hit:

BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id+0x18/0x24
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc1-00001-g6ae0aec8a366 #181
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Backtrace:
dump_backtrace from show_stack+0x20/0x24
r7:81024ffd r6:00000000 r5:81024ffd r4:60000013
show_stack from dump_stack_lvl+0x60/0x78
dump_stack_lvl from dump_stack+0x14/0x1c
r7:81024ffd r6:80f652de r5:80bec180 r4:819a2500
dump_stack from check_preemption_disabled+0xc8/0xf0
check_preemption_disabled from debug_smp_processor_id+0x18/0x24
r8:8119b7e0 r7:81205534 r6:819f5c00 r5:819f4c00 r4:c083d724
debug_smp_processor_id from __spi_sync+0x78/0x220
__spi_sync from spi_sync+0x34/0x4c
r10:bb7bf4e0 r9:c083d724 r8:00000007 r7:81a068c0 r6:822a83c0 r5:c083d724
r4:819f4c00
spi_sync from spi_mem_exec_op+0x338/0x370
r5:000000b4 r4:c083d910
spi_mem_exec_op from spi_nor_read_id+0x98/0xdc
r10:bb7bf4e0 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:82358040
r4:819f7c40
spi_nor_read_id from spi_nor_detect+0x38/0x114
r7:82358040 r6:00000000 r5:819f7c40 r4:819f7c40
spi_nor_detect from spi_nor_scan+0x11c/0xbec
r10:bb7bf4e0 r9:00000000 r8:00000000 r7:c083da4c r6:00000000 r5:00010101
r4:819f7c40
spi_nor_scan from spi_nor_probe+0x10c/0x2d0
r10:bb7bf4e0 r9:bb7bf4d0 r8:00000000 r7:819f4c00 r6:00000000 r5:00000000
r4:819f7c40

per-cpu access needs to be guarded against preemption.

Fixes: 6598b91b5ac3 ("spi: spi.c: Convert statistics to per-cpu u64_stats_t")
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David Jander <david@protonic.nl>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220609121334.2984808-1-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi.c: Convert statistics to per-cpu u64_stats_t

This change gives a dramatic performance improvement in the hot path,
since many costly spin_lock_irqsave() calls can be avoided.

On an i.MX8MM system with a MCP2518FD CAN controller connected via SPI,
the time the driver takes to handle interrupts, or in other words the time
the IRQ line of the CAN controller stays low is mainly dominated by the
time it takes to do 3 relatively short sync SPI transfers. The effect of
this patch is a reduction of this time from 136us down to only 98us.

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220524091808.2269898-1-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use helper for safer setting of driver_override

Use a helper to set driver_override to the reduce amount of duplicated
code.

Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220419113435.246203-8-krzysztof.kozlowski@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: core: Display return code when failing to transfer message

All the other calls to the controller driver display the error
return code. The return code is helpful to understand what went
wrong, so include it when failing to transfer one message.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220525165852.33167-3-eajames@linux.ibm.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: using pm_runtime_resume_and_get instead of pm_runtime_get_sync

Using pm_runtime_resume_and_get is more appropriate
for simplifing code

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Link: https://lore.kernel.org/r/20220418110226.2559081-1-chi.minghao@zte.com.cn
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: Initialize returned status in spi_setup

The previous commit that made bits-per-word validation conditional
results in leaving no unconditional affectation of the status variable.

Since the variable is returned at the end of the function, initialize
it to avoid returning an undefined value.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Fixes: b3fe2e516741 ("spi: core: Only check bits_per_word validity when explicitly provided")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220414084040.975520-1-paul.kocialkowski@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: Only check bits_per_word validity when explicitly provided

On SPI device probe, the core will call spi_setup in spi_add_device
before the corresponding driver was probed. When this happens, the
bits_per_word member of the device is not yet set by the driver,
resulting in the default being set to 8 bits-per-word.

However some controllers do not support 8 bits-per-word at all, which
results in a failure when checking the bits-per-word validity.

In order to support these devices, skip the bits-per-word validity
check when it is not explicitly provided by drivers.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Link: https://lore.kernel.org/r/20220412122207.130181-1-paul.kocialkowski@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: add dma_map_dev for __spi_unmap_msg()

Commit b470e10eb43f ("spi: core: add dma_map_dev for dma device") added
dma_map_dev for _spi_map_msg() but missed to add for unmap routine,
__spi_unmap_msg(), so add it now.

Fixes: b470e10eb43f ("spi: core: add dma_map_dev for dma device")
Cc: stable@vger.kernel.org # v5.14+
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20220406132238.1029249-1-vkoul@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

ACPI: bus: Eliminate acpi_bus_get_device()

Replace the last instance of acpi_bus_get_device(), added recently
by commit 87e59b36e5e2 ("spi: Support selection of the index of the
ACPI Spi Resource before alloc"), with acpi_fetch_acpi_dev() and
finally drop acpi_bus_get_device() that has no more users.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mark Brown <broonie@kernel.org>

spi: Fix erroneous sgs value with min_t()

While computing sgs in spi_map_buf(), the data type
used in min_t() for max_seg_size is 'unsigned int' where
as that of ctlr->max_dma_len is 'size_t'.

min_t(unsigned int,x,y) gives wrong results if one of x/y is
'size_t'

Consider the below examples on a 64-bit machine (ie size_t is
64-bits, and unsigned int is 32-bit).
case 1) min_t(unsigned int, 5, 0x100000001);
case 2) min_t(size_t, 5, 0x100000001);

Case 1 returns '1', where as case 2 returns '5'. As you can see
the result from case 1 is wrong.

This patch fixes the above issue by using the data type of the
parameters that are used in min_t with maximum data length.

Fixes: commit 1a4e53d2fc4f68aa ("spi: Fix invalid sgs value")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20220316175317.465-1-biju.das.jz@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: use specific last_cs instead of last_cs_enable

Commit d40f0b6f2e21 instroduced last_cs_enable to avoid setting
chipselect if it's not necessary, but it also introduces a bug. The
chipselect may not be set correctly on multi-device SPI busses. The
reason is that we can't judge the chipselect by bool last_cs_enable,
since chipselect may be modified after other devices were accessed.

So we should record the specific state of chipselect in case of
confusion.

Signed-off-by: Yun Zhou <yun.zhou@windriver.com>
Link: https://lore.kernel.org/r/20220217141234.72737-1-yun.zhou@windriver.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: use sysfs_emit() for printing statistics and add trailing newline

Use dedicated function sysfs_emit() that does some extra checking,
e.g. to ensure that no more than PAGESIZE bytes are written.
In addition add a trailing newline to the output, that makes it
better readable from the console.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/56e1588d-d53b-73e9-fdc8-7fe30bf91f11@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Retire legacy GPIO handling

All drivers using GPIOs as chip select have been rewritten to use
GPIO descriptors passing the ->use_gpio_descriptors flag. Retire
the code and fields used by the legacy GPIO API.

Do not drop the ->use_gpio_descriptors flag: it now only indicates
that we want to use GPIOs in addition to native chip selects.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220210231954.807904-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: make remove callback a void function

The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Replace acpi_bus_get_device()

Replace acpi_bus_get_device() that is going to be dropped with
acpi_fetch_acpi_dev().

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/2231987.ElGaqSPkdT@kreacher
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add API to count spi acpi resources

Some ACPI nodes may have more than one Spi Resource.
To be able to handle these case, its necessary to have
a way of counting these resources.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-5-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Support selection of the index of the ACPI Spi Resource before alloc

If a node contains more than one SPI resource it may be necessary to
use an index to select which one you want to allocate a spi device for.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-4-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Create helper API to lookup ACPI info for spi device

This can then be used to find a spi resource inside an
ACPI node, and allocate a spi device.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-3-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Make spi_alloc_device and spi_add_device public again

This functions were previously made private since they
were not used. However, these functions will be needed
again.

Partial revert of commit da21fde0fdb3
("spi: Make several public functions private to spi.c")

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-2-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add API to count spi acpi resources

Some ACPI nodes may have more than one Spi Resource.
To be able to handle these case, its necessary to have
a way of counting these resources.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-5-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Support selection of the index of the ACPI Spi Resource before alloc

If a node contains more than one SPI resource it may be necessary to
use an index to select which one you want to allocate a spi device for.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-4-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Create helper API to lookup ACPI info for spi device

This can then be used to find a spi resource inside an
ACPI node, and allocate a spi device.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-3-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Make spi_alloc_device and spi_add_device public again

This functions were previously made private since they
were not used. However, these functions will be needed
again.

Partial revert of commit da21fde0fdb3
("spi: Make several public functions private to spi.c")

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220121172431.6876-2-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix invalid sgs value

max_seg_size is unsigned int and it can have a value up to 2^32
(for eg:-RZ_DMAC driver sets dma_set_max_seg_size as U32_MAX)
When this value is used in min_t() as an integer type, it becomes
-1 and the value of sgs becomes 0.

Fix this issue by replacing the 'int' data type with 'unsigned int'
in min_t().

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20220307184843.9994-1-biju.das.jz@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: don't include ptp_clock_kernel.h in spi.h

Commit b42faeee718c ("spi: Add a PTP system timestamp
to the transfer structure") added an include of ptp_clock_kernel.h
to spi.h for struct ptp_system_timestamp but a forward declaration
is enough. Let's use that to limit the number of objects we have
to rebuild every time we touch networking headers.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20210904013140.2377609-1-kuba@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix incorrect cs_setup delay handling

Move the cs_setup delay to the end of spi_set_cs.

From include/linux/spi/spi.h:

* @cs_setup: delay to be introduced by the controller after CS is
asserted

The cs_setup delay needs to happen *after* CS is asserted, that is, at
the end of spi_set_cs, not at the beginning. Otherwise we're just
delaying before the SPI transaction starts at all, which isn't very
useful.

No drivers use this right now, but that is likely to change soon with an
upcoming Apple SPI HID transport driver.

Fixes: 25093bdeb6bc ("spi: implement SW control for CS times")
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20211210170534.177139-1-marcan@marcan.st
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix condition in the __spi_register_driver()

The recent commit 3f07657506df ("spi: deduplicate spi_match_id()
in __spi_register_driver()") inadvertently inverted a condition
that provokes a (harmless) warning:

WARNING KERN SPI driver mtd_dataflash has no spi_device_id for atmel,at45

Restore logic to avoid such warning to be issued.

Fixes: 3f07657506df ("spi: deduplicate spi_match_id() in __spi_register_driver()")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20211123170034.41253-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix multi-line comment style

/*
* Fix multi-line comment style as in this short example. Pay attention
* to the capitalization, period and starting line of the text.
*/

While at it, split the (supposedly short) description of couple of functions
to summary (short description) and (long) description.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211122171721.61553-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Replace memset() with __GFP_ZERO

krealloc() as any other kernel memory allocation calls accepts GFP flags,
one of which is __GFP_ZERO. Hence, no need to call memset() explicitly on
the reallocated buffer.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211122171721.61553-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: deduplicate spi_match_id() in __spi_register_driver()

The same logic is used in spi_match_id() and in the __spi_register_driver().
By switching the former from taking struct spi_device * to const char * as
the second parameter we may deduplicate the code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211119173718.52938-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fix use-after-free of the add_lock mutex

Commit 6098475d4cb4 ("spi: Fix deadlock when adding SPI controllers on
SPI buses") introduced a per-controller mutex. But mutex_unlock() of
said lock is called after the controller is already freed:

spi_unregister_controller(ctlr)
-> put_device(&ctlr->dev)
-> spi_controller_release(dev)
-> mutex_unlock(&ctrl->add_lock)

Move the put_device() after the mutex_unlock().

Fixes: 6098475d4cb4 ("spi: Fix deadlock when adding SPI controllers on SPI buses")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v5.15
Link: https://lore.kernel.org/r/20211111083713.3335171-1-michael@walle.cc
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Make several public functions private to spi.c

All these functions have no callers apart from drivers/spi/spi.c. So
drop their declarations in include/linux/spi/spi.h and don't export
them.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211007121415.2401638-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Reorder functions to simplify the next commit

Currently the "Core methods for SPI resource management" are exported
and public functions. They are however only used in drivers/spi/spi.c.
To allow to drop the global declarations and not to have to insert local
ones instead, move them before their users.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211007121415.2401638-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove unused function spi_busnum_to_master()

The last user is gone since commit

2962db71c703 ("staging/fbtft: Remove fbtft_device")

in 2019.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211007121415.2401638-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Move comment about chipselect check to the right place

The part of the comment about locking isn't that relevant compared to
the chip select check. So drop the sentence about locking.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211007121415.2401638-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Check we have a spi_device_id for each DT compatible

Currently for SPI devices we use the spi_device_id for module autoloading
even on systems using device tree, meaning that listing a compatible string
in the of_match_table isn't enough to have the module for a SPI driver
autoloaded.

We attempted to fix this by generating OF based modaliases for devices
instantiated from DT in 3ce6c9e2617e ("spi: add of_device_uevent_modalias
support") but this meant we no longer reported spi_device_id based aliases
which broke drivers such as spi-nor which don't list all the compatible
strings they support directly for DT, and in at least that case it's not
super practical to do so given the very large number of compatibles
needed, much larger than the number spi_device_ids due to vendor strings.
As a result fell back to using spi_device_id based modalises.

Try to close the gap by printing a warning when a SPI driver has a DT
compatible that won't be matched as a SPI device ID with the goal of having
drivers provide both. Given fallback compatibles this check is going to be
excessive but it should be robust which is probably more important here.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210921192149.50740-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi-mux: Fix false-positive lockdep splats

io_mutex is taken by spi_setup() and spi-mux's .setup() callback calls
spi_setup() which results in a nested lock of io_mutex.

add_lock is taken by spi_add_device(). The device_add() call in there
can result in calling spi-mux's .probe() callback which registers its
own spi controller which in turn results in spi_add_device() being
called again.

To fix this initialize the controller's locks already in
spi_alloc_controller() to give spi_mux_probe() a chance to set the
lockdep subclass.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211013133710.2679703-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix deadlock when adding SPI controllers on SPI buses

Currently we have a global spi_add_lock which we take when adding new
devices so that we can check that we're not trying to reuse a chip
select that's already controlled. This means that if the SPI device is
itself a SPI controller and triggers the instantiation of further SPI
devices we trigger a deadlock as we try to register and instantiate
those devices while in the process of doing so for the parent controller
and hence already holding the global spi_add_lock. Since we only care
about concurrency within a single SPI bus move the lock to be per
controller, avoiding the deadlock.

This can be easily triggered in the case of spi-mux.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Revert modalias changes

During the v5.13 cycle we updated the SPI subsystem to generate OF style
modaliases for SPI devices, replacing the old Linux style modalises we
used to generate based on spi_device_id which are the DT style name with
the vendor removed. Unfortunately this means that we start only
reporting OF style modalises and not the old ones and there is nothing
that ensures that drivers list every possible OF compatible string in
their OF ID table. The result is that there are systems which have been
relying on loading modules based on the old style that are now broken,
as found by Russell King with spi-nor on Macchiatobin.

spi-nor is a particularly problematic case for this, it only lists a
single generic DT compatible jedec,spi-nor in the driver but supports a
huge raft of device specific compatibles, with a large set of part
numbers many of which are offered by multiple vendors. Russell's
searches of upstream device trees has turned up examples with vendor
names written in non-standard ways too. To make matters worse up until
8ff16cf77ce3 ("Documentation: devicetree: m25p80: add "nor-jedec"
binding") the generic compatible was not part of the binding so there
are device trees out there written to that binding version which don't
list it all. The sheer number of parts supported together with our
previous approach of ignoring the vendor ID makes robustly fixing this
by adding compatibles to the spi-nor driver seem problematic, the
current DT binding document does not list all the parts supported by the
driver at the minute (further patches will fix this).

I've also investigated supporting both formats of modalias
simultaneously but that doesn't seem possible, especially without
breaking our userspace ABI which is obviously not viable.

Instead revert the relevant changes for now:

e09f2ab8eecc ("spi: update modalias_show after of_device_uevent_modalias support")
3ce6c9e2617e ("spi: add of_device_uevent_modalias support")

This will unfortunately mean that any system which had started having
modules autoload based on the OF compatibles for drivers that list
things there but not in the spi_device_ids will now not have those
modules load which is itself a regression. Since it affects a narrower
time window and the particularly problematic spi-nor driver may be
critical to system boot on smaller systems this seems the best of a
series of bad options. I will start an audit of SPI drivers to identify
and fix cases where things won't autoload using spi_device_id, this is
not great but seems to be the best way forward that anyone has been able
to identify.

Thanks to Russell for both his report and the additional diagnostic and
analysis work he has done here, the detailed research above was his
work.

Fixes: e09f2ab8eecc ("spi: update modalias_show after of_device_uevent_modalias support")
Fixes: 3ce6c9e2617e ("spi: add of_device_uevent_modalias support")
Reported-by: Russell King (Oracle) <linux@armlinux.org.uk>
Suggested-by: Russell King (Oracle) <linux@armlinux.org.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>
Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Cc: Andreas Schwab <schwab@suse.de>
Cc: Marco Felsch <m.felsch@pengutronix.de>

bus: Make remove callback return void

The driver core ignores the return value of this callback because there
is only little it can do when a device disappears.

This is the final bit of a long lasting cleanup quest where several
buses were converted to also return void from their remove callback.
Additionally some resource leaks were fixed that were caused by drivers
returning an error code in the expectation that the driver won't go
away.

With struct bus_type::remove returning void it's prevented that newly
implemented buses return an ignored error code and so don't anticipate
wrong expectations for driver authors.

Reviewed-by: Tom Rix <trix@redhat.com> (For fpga)
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com> (For drivers/s390 and drivers/vfio)
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> (For ARM, Amba and related parts)
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Chen-Yu Tsai <wens@csie.org> (for sunxi-rsb)
Acked-by: Pali Rohár <pali@kernel.org>
Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org> (for media)
Acked-by: Hans de Goede <hdegoede@redhat.com> (For drivers/platform)
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Acked-by: Juergen Gross <jgross@suse.com> (For xen)
Acked-by: Lee Jones <lee.jones@linaro.org> (For mfd)
Acked-by: Johannes Thumshirn <jth@kernel.org> (For mcb)
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> (For slimbus)
Acked-by: Kirti Wankhede <kwankhede@nvidia.com> (For vfio)
Acked-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> (For ulpi and typec)
Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com> (For ipack)
Acked-by: Geoff Levand <geoff@infradead.org> (For ps3)
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com> (For thunderbolt)
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> (For intel_th)
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net> (For pcmcia)
Acked-by: Rafael J. Wysocki <rafael@kernel.org> (For ACPI)
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> (rpmsg and apr)
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> (For intel-ish-hid)
Acked-by: Dan Williams <dan.j.williams@intel.com> (For CXL, DAX, and NVDIMM)
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> (For isa)
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (For firewire)
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> (For hid)
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de> (For siox)
Acked-by: Sven Van Asbroeck <TheSven73@gmail.com> (For anybuss)
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> (For MMC)
Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Finn Thain <fthain@linux-m68k.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210713193522.1770306-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: move cs spi_delay to spi_device

As we know, spi core layer has removed spi_set_cs_timing() API.
So this patch moved spi_delay for cs_timing from spi_controller
to spi_device, because cs timing should be set by spi_device but
not controller.

Signed-off-by: Mason Zhang <Mason.Zhang@mediatek.com>
Link: https://lore.kernel.org/r/20210804133716.32040-1-Mason.Zhang@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: update modalias_show after of_device_uevent_modalias support

Commit 3ce6c9e2617e ("spi: add of_device_uevent_modalias support") is
incomplete, as it didn't update the modalias_show function to generate the
of: modalias string if available.

Fixes: 3ce6c9e2617e ("spi: add of_device_uevent_modalias support")
Signed-off-by: Andreas Schwab <schwab@suse.de>
Link: https://lore.kernel.org/r/mvmwnpi4fya.fsf@suse.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: add dma_map_dev for dma device

Some controllers like qcom geni need the parent device to be used for
dma mapping, so add a dma_map_dev field and let drivers fill this to be
used as mapping device

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20210625052213.32260-4-vkoul@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix self assignment issue with ancillary->mode

There is an assignment of ancillary->mode to itself which looks
dubious since the proceeding comment states that the speed and
mode is taken over from the SPI main device, indicating that
ancillary->mode should assigned using the value spi->mode.
Fix this.

Addresses-Coverity: ("Self assignment")
Fixes: 0c79378c0199 ("spi: add ancillary device support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210623172300.161484-1-colin.king@canonical.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add ancillary device support

Introduce support for ancillary devices, similar to existing
implementation for I2C. This is useful for devices having
multiple chip-selects, for example some microcontrollers
provide a normal SPI interface and a flashing SPI interface.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20210621175359.126729-2-sebastian.reichel@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add of_device_uevent_modalias support

Add OF support as already done for ACPI to take driver
MODULE_DEVICE_TABLE(of, ..) into account.

For example with this change a spi nor device MODALIAS changes from:

MODALIAS=spi:spi-nor

to

MODALIAS=of:Nspi-flashT(null)Cjedec,spi-nor

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Link: https://lore.kernel.org/r/20210525091003.18228-1-m.felsch@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: remove spi_set_cs_timing()

No one seems to be using this global and exported function, so remove it
as it is no longer needed.

Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20210609071918.2852069-1-gregkh@linuxfoundation.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Enable tracing of the SPI setup CS selection

It is helpful to see what state of CS signal was during one
or another SPI operation. All the same for SPI setup.

Enable tracing of the SPI setup and CS selection.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Message-Id: <20210526195655.75691-1-andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use SPI_MODE_X_MASK

Use SPI_MODE_X_MASK instead of open coded variant.

While at it, fix format specifier and drop explicit casting.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210510131217.49357-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Convert to use predefined time multipliers

We have a lot of hard coded values in nanoseconds or other units.
Use predefined constants to make it more clear.

While at it, add or amend comments in the corresponding functions.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210510131120.49253-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Avoid undefined behaviour when counting unused native CSs

ffz(), that has been used to count unused native CSs,
might cause undefined behaviour when called against ~0U.
To fix that, open code it with ffs(~value) - 1.

Fixes: 7d93aecdb58d ("spi: Add generic support for unused native cs with cs-gpios")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420164425.40287-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Allow to have all native CSs in use along with GPIOs

The commit 7d93aecdb58d ("spi: Add generic support for unused native cs
with cs-gpios") excludes the valid case for the controllers that doesn't
need to switch native CS in order to perform the transfer, i.e. when

0 native
... ...
<n> - 1 native
<n> GPIO
<n> + 1 GPIO
... ...

where <n> defines maximum of native CSs supported by the controller.

To allow this, bail out from spi_get_gpio_descs() conditionally for
the controllers which explicitly marked with SPI_MASTER_GPIO_SS.

Fixes: 7d93aecdb58d ("spi: Add generic support for unused native cs with cs-gpios")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420164425.40287-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Make of_register_spi_device also set the fwnode

Currently, the SPI core doesn't set the struct device fwnode pointer
when it creates a new SPI device. This means when the device is
registered the fwnode is NULL and the check in device_add which sets
the fwnode->dev pointer is skipped. This wasn't previously an issue,
however these two patches:

commit 4731210c09f5 ("gpiolib: Bind gpio_device to a driver to enable
fw_devlink=on by default")
commit ced2af419528 ("gpiolib: Don't probe gpio_device if it's not the
primary device")

Added some code to the GPIO core which relies on using that
fwnode->dev pointer to determine if a driver is bound to the fwnode
and if not bind a stub GPIO driver. This means the GPIO providers
behind SPI will get both the expected driver and this stub driver
causing the stub driver to fail if it attempts to request any pin
configuration. For example on my system:

madera-pinctrl madera-pinctrl: pin gpio5 already requested by madera-pinctrl; cannot claim for gpiochip3
madera-pinctrl madera-pinctrl: pin-4 (gpiochip3) status -22
madera-pinctrl madera-pinctrl: could not request pin 4 (gpio5) from group aif1 on device madera-pinctrl
gpio_stub_drv gpiochip3: Error applying setting, reverse things back
gpio_stub_drv: probe of gpiochip3 failed with error -22

The firmware node on the device created by the GPIO framework is set
through the of_node pointer hence things generally actually work,
however that fwnode->dev is never set, as the check was skipped at
device_add time. This fix appears to match how the I2C subsystem
handles the same situation.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210421101402.8468-1-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Don't have controller clean up spi device before driver unbind

When a spi device is unregistered and triggers a driver unbind, the
driver might need to access the spi device. So, don't have the
controller clean up the spi device before the driver is unbound. Clean
up the spi device after the driver is unbound.

Fixes: c7299fea6769 ("spi: Fix spi device unregister flow")
Reported-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210505164734.175546-1-saravanak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Assume GPIO CS active high in ACPI case

Currently GPIO CS handling, when descriptors are in use, doesn't
take into consideration that in ACPI case the default polarity
is Active High and can't be altered. Instead we have to use the
per-chip definition provided by SPISerialBus() resource.

Fixes: 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors")
Cc: Liguang Zhang <zhangliguang@linux.alibaba.com>
Cc: Jay Fang <f.fangjian@huawei.com>
Cc: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210511140912.30757-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: take the SPI IO-mutex in the spi_set_cs_timing method

this patch takes the io_mutex to prevent an unprotected HW
register modification in the set_cs_timing callback.

Fixes: 4cea6b8cc34e ("spi: add power control when set_cs_timing")
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Link: https://lore.kernel.org/r/20210508060214.1485-1-leilk.liu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix spi device unregister flow

When an SPI device is unregistered, the spi->controller->cleanup() is
called in the device's release callback. That's wrong for a couple of
reasons:

1. spi_dev_put() can be called before spi_add_device() is called. And
it's spi_add_device() that calls spi_setup(). This will cause clean()
to get called without the spi device ever being setup.

2. There's no guarantee that the controller's driver would be present by
the time the spi device's release function gets called.

3. It also causes "sleeping in atomic context" stack dump[1] when device
link deletion code does a put_device() on the spi device.

Fix these issues by simply moving the cleanup from the device release
callback to the actual spi_unregister_device() function.

[1] - https://lore.kernel.org/lkml/CAHp75Vc=FCGcUyS0v6fnxme2YJ+qD+Y-hQDQLa2JhWNON9VmsQ@mail.gmail.com/

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210426235638.1285530-1-saravanak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Rename enable1 to activate in spi_set_cs()

The enable1 is confusing name. Change it to clearly show what is
the intention behind it. No functional changes.

Fixes: 25093bdeb6bc ("spi: implement SW control for CS times")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420131846.75983-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Make error handling of gpiod_count() call cleaner

Each time we call spi_get_gpio_descs() the num_chipselect is overwritten
either by new value or by the old one. This is an extra operation in case
gpiod_count() returns an error. Besides that it slashes the error handling
of gpiod_count().

Refactor the code to make error handling of gpiod_count() call cleaner.

Note, that gpiod_count() never returns 0, take this into account as well.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420164040.40055-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Handle SPI device setup callback failure.

If the setup callback failed, but the controller has auto_runtime_pm
and set_cs, the setup failure could be missed.

Signed-off-by: Joe Burmeister <joe.burmeister@devtank.co.uk>
Link: https://lore.kernel.org/r/20210419130631.4586-1-joe.burmeister@devtank.co.uk
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: sync up initial chipselect state

When initially probing the SPI slave device, the call for disabling an
SPI device without the SPI_CS_HIGH flag is not applied, as the
condition for checking whether or not the state to be applied equals the
one currently set evaluates to true.

This however might not necessarily be the case, as the chipselect might
be active.

Add a force flag to spi_set_cs which allows to override this
early exit condition. Set it to false everywhere except when called
from spi_setup to sync up the initial CS state.

Fixes commit d40f0b6f2e21 ("spi: Avoid setting the chip select if we don't
need to")

Signed-off-by: David Bauer <mail@david-bauer.net>
Link: https://lore.kernel.org/r/20210416195956.121811-1-mail@david-bauer.net
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: simplify devm_spi_register_controller

Use devm_add_action_or_reset() instead of devres_alloc() and
devres_add(), which works the same. This will simplify the
code. There is no functional changes.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1617843307-53853-1-git-send-email-tiantao6@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix use-after-free with devm_spi_alloc_*

We can't rely on the contents of the devres list during
spi_unregister_controller(), as the list is already torn down at the
time we perform devres_find() for devm_spi_release_controller. This
causes devices registered with devm_spi_alloc_{master,slave}() to be
mistakenly identified as legacy, non-devm managed devices and have their
reference counters decremented below 0.

------------[ cut here ]------------
WARNING: CPU: 1 PID: 660 at lib/refcount.c:28 refcount_warn_saturate+0x108/0x174
[<b0396f04>] (refcount_warn_saturate) from [<b03c56a4>] (kobject_put+0x90/0x98)
[<b03c5614>] (kobject_put) from [<b0447b4c>] (put_device+0x20/0x24)
r4:b6700140
[<b0447b2c>] (put_device) from [<b07515e8>] (devm_spi_release_controller+0x3c/0x40)
[<b07515ac>] (devm_spi_release_controller) from [<b045343c>] (release_nodes+0x84/0xc4)
r5:b6700180 r4:b6700100
[<b04533b8>] (release_nodes) from [<b0454160>] (devres_release_all+0x5c/0x60)
r8:b1638c54 r7:b117ad94 r6:b1638c10 r5:b117ad94 r4:b163dc10
[<b0454104>] (devres_release_all) from [<b044e41c>] (__device_release_driver+0x144/0x1ec)
r5:b117ad94 r4:b163dc10
[<b044e2d8>] (__device_release_driver) from [<b044f70c>] (device_driver_detach+0x84/0xa0)
r9:00000000 r8:00000000 r7:b117ad94 r6:b163dc54 r5:b1638c10 r4:b163dc10
[<b044f688>] (device_driver_detach) from [<b044d274>] (unbind_store+0xe4/0xf8)

Instead, determine the devm allocation state as a flag on the
controller which is guaranteed to be stable during cleanup.

Fixes: 5e844cc37a5c ("spi: Introduce device-managed SPI controller allocation")
Signed-off-by: William A. Kennington III <wak@google.com>
Link: https://lore.kernel.org/r/20210407095527.2771582-1-wak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix spelling mistake "softwade" -> "software"

There is a spelling mistake in a dev_err message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210317093936.5572-1-colin.king@canonical.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove support for dangling device properties

>From now on only accepting complete software nodes.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20210303152814.35070-5-heikki.krogerus@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add support for software nodes

Making it possible for the drivers to assign complete
software fwnodes to the devices instead of only the device
properties in those nodes.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20210303152814.35070-2-heikki.krogerus@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: remove 'delay_usecs' field from spi_transfer

The 'delay' field in the spi_transfer struct is meant to replace the
'delay_usecs' field. However some cleanup was required to remove the
uses of 'delay_usecs'. Now that it's been cleaned up, we can remove it
from the kernel tree.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210308145502.1075689-10-aardelean@deviqon.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Skip zero-length transfers in spi_transfer_one_message()

With the introduction of 26751de25d25 ("spi: bcm2835: Micro-optimise
FIFO loops") it has become apparent that some users might initiate
zero-length SPI transfers. A fact the micro-optimization omitted, and
which turned out to cause crashes[1].

Instead of changing the micro-optimization itself, use a bigger hammer
and skip zero-length transfers altogether for drivers using the default
transfer_one_message() implementation.

Reported-by: Phil Elwell <phil@raspberrypi.com>
Fixes: 26751de25d25 ("spi: bcm2835: Micro-optimise FIFO loops")
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

[1] https://github.com/raspberrypi/linux/issues/4100
Link: https://lore.kernel.org/r/20210211180820.25757-1-nsaenzjulienne@suse.de

Signed-off-by: Mark Brown <broonie@kernel.org>

spi: support CS timing for HW & SW mode

this patch supports the controller's HW CS and SW CS via use cs_gpio.

Signed-off-by: leilk.liu <leilk.liu@mediatek.com>
Link: https://lore.kernel.org/r/20210207030953.9297-3-leilk.liu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add power control when set_cs_timing

As to set_cs_timing takes effect immediately, power spi
is needed when call spi_set_cs_timing.

Signed-off-by: leilk.liu <leilk.liu@mediatek.com>
Link: https://lore.kernel.org/r/20210207030953.9297-2-leilk.liu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add SPI_NO_TX/RX support

Transmit/receive only is a valid SPI mode. For example, the MOSI/TX line
might be missing from an ADC while for a DAC the MISO/RX line may be
optional. This patch adds these two new modes: SPI_NO_TX and
SPI_NO_RX. This way, the drivers will be able to identify if any of
these two lines is missing and to adjust the transfers accordingly.

Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201221152936.53873-2-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

ACPI: Test for ACPI_SUCCESS rather than !ACPI_FAILURE

The double negative makes it hard to read "if (!ACPI_FAILURE(status))".
Replace it with "if (ACPI_SUCCESS(status))".

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

spi: fix the divide by 0 error when calculating xfer waiting time

The xfer waiting time is the result of xfer->len / xfer->speed_hz. This
patch makes the assumption of 100khz xfer speed if the xfer->speed_hz is
not assigned and stays 0. This avoids the divide by 0 issue and ensures
a reasonable tolerant waiting time.

Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/1609723749-3557-1-git-send-email-yilun.xu@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix the clamping of spi->max_speed_hz

If spi->controller->max_speed_hz is zero, a non-zero spi->max_speed_hz
will be overwritten by zero. Make sure spi->controller->max_speed_hz
is not zero when clamping spi->max_speed_hz.

Put the spi->controller->max_speed_hz non-zero check higher in the if,
so that we avoid a superfluous init to zero when both spi->max_speed_hz
and spi->controller->max_speed_hz are zero.

Fixes: 9326e4f1e5dd ("spi: Limit the spi device max speed to controller's max speed")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20201216092321.413262-1-tudor.ambarus@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Limit the spi device max speed to controller's max speed

Make sure the max_speed_hz of spi_device does not override
the max_speed_hz of controller.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20201209173514.93328-1-tudor.ambarus@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix potential NULL pointer dereference in spi_shutdown()

Shutdown bus function might be called on the unbound device, so add a
check if there is a driver before calling its shutdown function.

This fixes following kernel panic obserbed during system reboot:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018
...
Call trace:
spi_shutdown+0x10/0x38
kernel_restart_prepare+0x34/0x40
kernel_restart+0x14/0x88
__do_sys_reboot+0x148/0x248
__arm64_sys_reboot+0x1c/0x28
el0_svc_common.constprop.3+0x74/0x198
do_el0_svc+0x20/0x98
el0_sync_handler+0x140/0x1a8
el0_sync+0x140/0x180
Code: f9403402 d1008041 f100005f 9a9f1021 (f9400c21)
---[ end trace 266c07205a2d632e ]---

Fixes: 9db34ee64ce4 (spi: Use bus_type functions for probe, remove and shutdown)
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20201124131523.32287-1-m.szyprowski@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Take the SPI IO-mutex in the spi_setup() method

I've discovered that due to the recent commit 49d7d695ca4b ("spi: dw:
Explicitly de-assert CS on SPI transfer completion") a concurrent usage of
the spidev devices with different chip-selects causes the "SPI transfer
timed out" error. The root cause of the problem has turned to be in a race
condition of the SPI-transfer execution procedure and the spi_setup()
method being called at the same time. In particular in calling the
spi_set_cs(false) while there is an SPI-transfer being executed. In my
case due to the commit cited above all CSs get to be switched off by
calling the spi_setup() for /dev/spidev0.1 while there is an concurrent
SPI-transfer execution performed on /dev/spidev0.0. Of course a situation
of the spi_setup() being called while there is an SPI-transfer being
executed for two different SPI peripheral devices of the same controller
may happen not only for the spidev driver, but for instance for MMC SPI +
some another device, or spi_setup() being called from an SPI-peripheral
probe method while some other device has already been probed and is being
used by a corresponding driver...

Of course I could have provided a fix affecting the DW APB SSI driver
only, for instance, by creating a mutual exclusive access to the set_cs
callback and setting/clearing only the bit responsible for the
corresponding chip-select. But after a short research I've discovered that
the problem most likely affects a lot of the other drivers:
- drivers/spi/spi-sun4i.c - RMW the chip-select register;
- drivers/spi/spi-rockchip.c - RMW the chip-select register;
- drivers/spi/spi-qup.c - RMW a generic force-CS flag in a CSR.
- drivers/spi/spi-sifive.c - set a generic CS-mode flag in a CSR.
- drivers/spi/spi-bcm63xx-hsspi.c - uses an internal mutex to serialize
the bus config changes, but still isn't protected from the race
condition described above;
- drivers/spi/spi-geni-qcom.c - RMW a chip-select internal flag and set the
CS state in HW;
- drivers/spi/spi-orion.c - RMW a chip-select register;
- drivers/spi/spi-cadence.c - RMW a chip-select register;
- drivers/spi/spi-armada-3700.c - RMW a chip-select register;
- drivers/spi/spi-lantiq-ssc.c - overwrites the chip-select register;
- drivers/spi/spi-sun6i.c - RMW a chip-select register;
- drivers/spi/spi-synquacer.c - RMW a chip-select register;
- drivers/spi/spi-altera.c - directly sets the chip-select state;
- drivers/spi/spi-omap2-mcspi.c - RMW an internally cached CS state and
writes it to HW;
- drivers/spi/spi-mt65xx.c - RMW some CSR;
- drivers/spi/spi-jcore.c - directly sets the chip-selects state;
- drivers/spi/spi-mt7621.c - RMW a chip-select register;

I could have missed some drivers, but a scale of the problem is obvious.
As you can see most of the drivers perform an unprotected
Read-modify-write chip-select register modification in the set_cs callback.
Seeing the spi_setup() function is calling the spi_set_cs() and it can be
executed concurrently with SPI-transfers exec procedure, which also calls
spi_set_cs() in the SPI core spi_transfer_one_message() method, the race
condition of the register modification turns to be obvious.

To sum up the problem denoted above affects each driver for a controller
having more than one chip-select lane and which:
1) performs the RMW to some CS-related register with no serialization;
2) directly disables any CS on spi_set_cs(dev, false).
* the later is the case of the DW APB SSI driver.

The controllers which equipped with a single CS theoretically can also
experience the problem, but in practice will not since normally the
spi_setup() isn't called concurrently with the SPI-transfers executed on
the same SPI peripheral device.

In order to generically fix the denoted bug I'd suggest to serialize an
access to the controller IO by taking the IO mutex in the spi_setup()
callback. The mutex is held while there is an SPI communication going on
on the SPI-bus of the corresponding SPI-controller. So calling the
spi_setup() method and disabling/updating the CS state within it would be
safe while there is no any SPI-transfers being executed. Also note I
suppose it would be safer to protect the spi_controller->setup() callback
invocation too, seeing some of the SPI-controller drivers update a HW
state in there.

Fixes: 49d7d695ca4b ("spi: dw: Explicitly de-assert CS on SPI transfer completion")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201117094517.5654-1-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Warn when a driver's remove callback returns an error

The driver core ignores the return value of struct device_driver::remove
(because in general there is nothing that can be done about that). So
add a warning when an spi driver returns an error.

This simplifies the quest to make struct device_driver::remove return void.
A consequent change would be to make struct spi_driver::remove return void,
but I'm keeping this quest for later (or someone else).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201119161604.2633521-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use bus_type functions for probe, remove and shutdown

The eventual goal is to get rid of the callbacks in struct
device_driver. Other than not using driver callbacks there should be no
side effect of this patch.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201119161604.2633521-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fix resource leak for drivers without .remove callback

Consider an spi driver with a .probe but without a .remove callback (e.g.
rtc-ds1347). The function spi_drv_probe() is called to bind a device and
so dev_pm_domain_attach() is called. As there is no remove callback
spi_drv_remove() isn't called at unbind time however and so calling
dev_pm_domain_detach() is missed and the pm domain keeps active.

To fix this always use both spi_drv_probe() and spi_drv_remove() and
make them handle the respective callback not being set. This has the
side effect that for a (hypothetical) driver that has neither .probe nor
remove the clk and pm domain setup is done.

Fixes: 33cf00e57082 ("spi: attach/detach SPI device to the ACPI power domain")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201119161604.2633521-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Introduce device-managed SPI controller allocation

SPI driver probing currently comprises two steps, whereas removal
comprises only one step:

spi_alloc_master()
spi_register_controller()

spi_unregister_controller()

That's because spi_unregister_controller() calls device_unregister()
instead of device_del(), thereby releasing the reference on the
spi_controller which was obtained by spi_alloc_master().

An SPI driver's private data is contained in the same memory allocation
as the spi_controller struct. Thus, once spi_unregister_controller()
has been called, the private data is inaccessible. But some drivers
need to access it after spi_unregister_controller() to perform further
teardown steps.

Introduce devm_spi_alloc_master() and devm_spi_alloc_slave(), which
release a reference on the spi_controller struct only after the driver
has unbound, thereby keeping the memory allocation accessible. Change
spi_unregister_controller() to not release a reference if the
spi_controller was allocated by one of these new devm functions.

The present commit is small enough to be backportable to stable.
It allows fixing drivers which use the private data in their ->remove()
hook after it's been freed. It also allows fixing drivers which neglect
to release a reference on the spi_controller in the probe error path.

Long-term, most SPI drivers shall be moved over to the devm functions
introduced herein. The few that can't shall be changed in a treewide
commit to explicitly release the last reference on the controller.
That commit shall amend spi_unregister_controller() to no longer release
a reference, thereby completing the migration.

As a result, the behaviour will be less surprising and more consistent
with subsystems such as IIO, which also includes the private data in the
allocation of the generic iio_dev struct, but calls device_del() in
iio_device_unregister().

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/272bae2ef08abd21388c98e23729886663d19192.1605121038.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fix client driver breakages when using GPIO descriptors

Commit f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
introduced the optional use of GPIO descriptors for chip selects.

A side-effect of this change: when a SPI bus uses GPIO descriptors,
all its client devices have SPI_CS_HIGH set in spi->mode. This flag is
required for the SPI bus to operate correctly.

This unfortunately breaks many client drivers, which use the following
pattern to configure their underlying SPI bus:

static int client_device_probe(struct spi_device *spi)
{
...
spi->mode = SPI_MODE_0;
spi->bits_per_word = 8;
err = spi_setup(spi);
..
}

In short, many client drivers overwrite the SPI_CS_HIGH bit in
spi->mode, and break the underlying SPI bus driver.

This is especially true for Freescale/NXP imx ecspi, where large
numbers of spi client drivers now no longer work.

Proposed fix:
-------------
When using gpio descriptors, depend on gpiolib to handle CS polarity.
Existing quirks in gpiolib ensure that this is handled correctly.

Existing gpiolib behaviour will force the polarity of any chip-select
gpiod to active-high (if 'spi-active-high' devicetree prop present) or
active-low (if 'spi-active-high' absent). Irrespective of whether
the gpio is marked GPIO_ACTIVE_[HIGH|LOW] in the devicetree.

Loose ends:
-----------
If this fix is applied:
- is commit 138c9c32f090
("spi: spidev: Fix CS polarity if GPIO descriptors are used")
still necessary / correct ?

Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20201106150706.29089-1-TheSven73@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fix a typo inside a kernel-doc markup

spi_split_tranfers_maxsize -> spi_split_transfers_maxsize

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/a103f4f48735caa1a09fad94c5d76e73e2ce37b8.1603469755.git.mchehab+huawei@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix memory leak on splited transfers

In the prepare_message callback the bus driver has the
opportunity to split a transfer into smaller chunks.
spi_map_msg is done after prepare_message.

Function spi_res_release releases the splited transfers
in the message. Therefore spi_res_release should be called
after spi_map_msg.

The previous try at this was commit c9ba7a16d0f1
which released the splited transfers after
spi_finalize_current_message had been called.
This introduced a race since the message struct could be
out of scope because the spi_sync call got completed.

Fixes this leak on spi bus driver spi-bcm2835.c when transfer
size is greater than 65532:

Kmemleak:
sg_alloc_table+0x28/0xc8
spi_map_buf+0xa4/0x300
__spi_pump_messages+0x370/0x748
__spi_sync+0x1d4/0x270
spi_sync+0x34/0x58
spi_test_execute_msg+0x60/0x340 [spi_loopback_test]
spi_test_run_iter+0x548/0x578 [spi_loopback_test]
spi_test_run_test+0x94/0x140 [spi_loopback_test]
spi_test_run_tests+0x150/0x180 [spi_loopback_test]
spi_loopback_test_probe+0x50/0xd0 [spi_loopback_test]
spi_drv_probe+0x84/0xe0

Signed-off-by: Gustav Wiklander <gustavwi@axis.com>
Link: https://lore.kernel.org/r/20200908151129.15915-1-gustav.wiklander@axis.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Prevent adding devices below an unregistering controller

CONFIG_OF_DYNAMIC and CONFIG_ACPI allow adding SPI devices at runtime
using a DeviceTree overlay or DSDT patch. CONFIG_SPI_SLAVE allows the
same via sysfs.

But there are no precautions to prevent adding a device below a
controller that's being removed. Such a device is unusable and may not
even be able to unbind cleanly as it becomes inaccessible once the
controller has been torn down. E.g. it is then impossible to quiesce
the device's interrupt.

of_spi_notify() and acpi_spi_notify() do hold a ref on the controller,
but otherwise run lockless against spi_unregister_controller().

Fix by holding the spi_add_lock in spi_unregister_controller() and
bailing out of spi_add_device() if the controller has been unregistered
concurrently.

Fixes: ce79d54ae447 ("spi/of: Add OF notifier handler")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v3.19+
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Octavian Purdila <octavian.purdila@intel.com>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Link: https://lore.kernel.org/r/a8c3205088a969dc8410eec1eba9aface60f36af.1596451035.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Only defer to thread for cleanup when needed

Currently we always defer idling of controllers to the SPI thread, the goal
being to ensure that we're doing teardown that's not suitable for atomic
context in an appropriate context and to try to batch up more expensive
teardown operations when the system is under higher load, allowing more
work to be started before the SPI thread is scheduled. However when the
controller does not require any substantial work to idle there is no need
to do this, we can instead save the context switch and immediately mark
the controller as idle. This is particularly useful for systems where there
is frequent but not constant activity.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20200715163610.9475-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: use kthread_create_worker() helper

Use kthread_create_worker() helper to simplify the code. It uses
the kthread worker API the right way. It will eventually allow
to remove the FIXME in kthread_worker_fn() and add more consistency
checks in the future.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200709065007.26896-1-m.szyprowski@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Avoid setting the chip select if we don't need to

On some SPI controllers (like spi-geni-qcom) setting the chip select
is a heavy operation. For instance on spi-geni-qcom, with the current
code, is was measured as taking upwards of 20 us. Even on SPI
controllers that aren't as heavy, setting the chip select is at least
something like a MMIO operation over some peripheral bus which isn't
as fast as a RAM access.

While it would be good to find ways to mitigate problems like this in
the drivers for those SPI controllers, it can also be noted that the
SPI framework could also help out. Specifically, in some situations,
we can see the SPI framework calling the driver's set_cs() with the
same parameter several times in a row. This is specifically observed
when looking at the way the Chrome OS EC SPI driver (cros_ec_spi)
works but other drivers likely trip it to some extent.

Let's solve this by caching the chip select state in the core and only
calling into the controller if there was a change. We check not only
the "enable" state but also the chip select mode (active high or
active low) since controllers may care about both the mode and the
enable flag in their callback.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200629164103.1.Ied8e8ad8bbb2df7f947e3bc5ea1c315e041785a2@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: introduce fallback to pio

Add fallback to pio mode in case dma transfer failed with error status
SPI_TRANS_FAIL_NO_START.
If spi client driver want to enable this feature please set xfer->error in
the proper place such as dmaengine_prep_slave_sg() failure detect(but no
any data put into spi bus yet). Besides, add master->fallback checking in
its can_dma() so that spi core could switch to pio next time. Please refer
to spi-imx.c.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Link: https://lore.kernel.org/r/1592347329-28363-2-git-send-email-yibin.gong@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sched,spi: Convert to sched_set_fifo*()

Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.

No effective change.

Cc: broonie@kernel.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>

spi: Remove note about transfer limit for spi_write_then_read()

Originally spi_write_then_read() used a fixed statically allocated
buffer which limited the maximum message size it could handle. This
restriction was removed a while ago so that we could dynamically
allocate a buffer if required but the kerneldoc was not updated to
reflect this, do so.

Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20200525133120.57273-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: flags 'SPI_CONTROLLER_MUST_RX' and 'SPI_CONTROLLER_MUST_TX' can't be coexit with 'SPI_3WIRE' mode

since chip spi driver need get the transfer direction by 'tx_buf' and
'rx_buf' of 'struct spi_transfer' in 'SPI_3WIRE' mode.

so, we need bypass 'SPI_CONTROLLER_MUST_RX' and 'SPI_CONTROLLER_MUST_TX'
feature in 'SPI_3WIRE' mode

Signed-off-by: dillon min <dillon.minfei@gmail.com>
Link: https://lore.kernel.org/r/1590378348-8115-9-git-send-email-dillon.minfei@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Make spi_delay_exec() warn if called from atomic context

If the delay used is long enough the spi_delay_exec() will use a sleeping
function to implement it. Add a might_sleep() here to help avoid callers
using this from an atomic context and running into problems at runtime on
other systems.

Suggested-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200522155005.46099-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix controller unregister order

When an SPI controller unregisters, it unbinds all its slave devices.
For this, their drivers may need to access the SPI bus, e.g. to quiesce
interrupts.

However since commit ffbbdd21329f ("spi: create a message queueing
infrastructure"), spi_destroy_queue() is executed before unbinding the
slaves. It sets ctlr->running = false, thereby preventing SPI bus
access and causing unbinding of slave devices to fail.

Fix by unbinding slaves before calling spi_destroy_queue().

Fixes: ffbbdd21329f ("spi: create a message queueing infrastructure")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v3.4+
Cc: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/8aaf9d44c153fe233b17bc2dec4eb679898d7e7b.1589557526.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: remove redundant assignment to variable ms

The variable ms is being initialized with a value that is never read
and it is being updated later with a new value. The initialization is
redundant and can be removed.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Addresses-Coverity: ("Unused value")
Link: https://lore.kernel.org/r/20200410122315.17523-1-colin.king@canonical.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Respect DataBitLength field of SpiSerialBusV2() ACPI resource

By unknown reason the commit 64bee4d28c9e
("spi / ACPI: add ACPI enumeration support")
missed the DataBitLength property to encounter when parse SPI slave
device data from ACPI.

Fill the gap here.

Fixes: 64bee4d28c9e ("spi / ACPI: add ACPI enumeration support")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200413180406.1826-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: acpi: remove superfluous parameter check

to_spi_device() already checks 'dev'. No need to do it before calling
it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20200312134507.10000-1-wsa@the-dreams.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: make spi-max-frequency optional

We only need a spi-max-frequency when we specifically request a
spi frequency lower than the max speed of spi host.
This property is already documented as optional property and current
host drivers are implemented to operate at highest speed possible
when spi->max_speed_hz is 0.
This patch makes spi-max-frequency an optional property so that
we could just omit it to use max controller speed.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Link: https://lore.kernel.org/r/20200306085052.28258-2-gch981213@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Do spi_take_timestamp_pre for as many times as necessary

When dealing with a SPI controller driver that is sending more than 1
byte at once (or the entire buffer at once), and the SPI peripheral
driver has requested timestamping for a byte in the middle of the
buffer, we find that spi_take_timestamp_pre never records a "pre"
timestamp.

This happens because the function currently expects to be called with
the "progress" argument >= to what the peripheral has requested to be
timestamped. But clearly there are cases when that isn't going to fly.

And since we can't change the past when we realize that the opportunity
to take a "pre" timestamp has just passed and there isn't going to be
another one, the approach taken is to keep recording the "pre" timestamp
on each call, overwriting the previously recorded one until the "post"
timestamp is also taken.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-8-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi_register_controller(): free bus id on error paths

Some error paths leave the bus id allocated. As a result the IDR
allocation will fail after a deferred probe. Fix by freeing the bus id
always on error.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Message-Id: <20200304111740.27915-1-aaro.koskinen@nokia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Allow SPI controller override device buswidth

Currently ACPI firmware description for a SPI device does not have any
method to describe the data buswidth on the board.

So even through the controller and device may support higher modes than
standard SPI, it cannot be assumed that the board does - as such, that
device is limited to standard SPI in such a circumstance.

As a workaround, allow the controller driver supply buswidth override bits,
which are used inform the core code that the controller driver knows the
buswidth supported on that board for that device.

A host controller driver might know this info from DMI tables, for example.

Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1582903131-160033-2-git-send-email-john.garry@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add generic support for unused native cs with cs-gpios

Some SPI master controllers always drive a native chip select when
performing a transfer. Hence when using both native and GPIO chip
selects, at least one native chip select must be left unused, to be
driven when performing transfers with slave devices using GPIO chip
selects.

Currently, to find an unused native chip select, SPI controller drivers
need to parse and process cs-gpios theirselves. This is not only
duplicated in each driver that needs it, but also duplicates part of the
work done later at SPI controller registration time. Note that this
cannot be done after spi_register_controller() returns, as at that time,
slave devices may have been probed already.

Hence add generic support to the SPI subsystem for finding an unused
native chip select. Optionally, this unused native chip select, and all
other in-use native chip selects, can be validated against the maximum
number of native chip selects available on the controller hardware.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200102133822.29346-2-geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Don't look at TX buffer for PTP system timestamping

The API for PTP system timestamping (associating a SPI transaction with
the system time at which it was transferred) is flawed: it assumes that
the xfer->tx_buf pointer will always be present.

This is, of course, not always the case.

So introduce a "progress" variable that denotes how many word have been
transferred.

Fix the Freescale DSPI driver, the only user of the API so far, in the
same patch.

Fixes: b42faeee718c ("spi: Add a PTP system timestamp to the transfer structure")
Fixes: d6b71dfaeeba ("spi: spi-fsl-dspi: Implement the PTP system timestamping for TCFQ mode")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191227012417.1057-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Catch improper use of PTP system timestamping API

We can catch whether the SPI controller has declared it can take care of
software timestamping transfers, but didn't. So do it.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191227012444.1204-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix regression to return zero on success instead of positive value

Commit d948e6ca1899 ("spi: add power control when set_cs") added generic
runtime PM handling, but also changed the return value to be 1 instead
of 0 that we had earlier as pm_runtime_get functions return a positve
value on success.

This causes SPI devices to return errors for cases where they do:

ret = spi_setup(spi);
if (ret)
return ret;

As in many cases the SPI devices do not check for if (ret < 0).

Let's fix this by setting the status to 0 on succeess after the
runtime PM calls. Let's not return 0 at the end of the function
as this might break again later on if the function changes and
starts returning status again.

Fixes: d948e6ca1899 ("spi: add power control when set_cs")
Cc: Luhua Xu <luhua.xu@mediatek.com>
Cc: wsd_upstream@mediatek.com
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20191111195334.44833-1-tony@atomide.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add power control when set_cs

As to set_cs takes effect immediately, power spi
is needed when setup spi.

Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Luhua Xu <luhua.xu@mediatek.com>
Link: https://lore.kernel.org/r/1572426234-30019-1-git-send-email-luhua.xu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix NULL pointer when setting SPI_CS_HIGH for GPIO CS

Even if the flag use_gpio_descriptors is set, it is possible that
cs_gpiods was not allocated, which leads to a kernel crash.

Reported-by: "kernelci.org bot" <bot@kernelci.org>
Fixes: 3e5ec1db8bfe ("spi: Fix SPI_CS_HIGH setting when using native and GPIO CS")
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191024141309.22434-1-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: <stable@vger.kernel.org>

spi: Fix spelling in the comments

Two spelling mistakes are being fixed.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20191023121643.25237-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix SPI_CS_HIGH setting when using native and GPIO CS

When improving the CS GPIO support at core level, the SPI_CS_HIGH
has been enabled for all the CS lines used for a given SPI controller.

However, the SPI framework allows to have on the same controller native
CS and GPIO CS. The native CS may not support the SPI_CS_HIGH, so they
should not be setup automatically.

With this patch the setting is done only for the CS that will use a
GPIO as CS

Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
Cc: <stable@vger.kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191018152929.3287-1-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-espi: convert transfer delay to `spi_delay` format

The way the max delay is computed for this controller, it looks like it is
searching for the max delay from an SPI message a using that.

No idea if this is valid. But this change should support both `delay_usecs`
and the new `delay` data which is of `spi_delay` type.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-17-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: implement SW control for CS times

This change implements CS control for setup, hold & inactive delays.

The `cs_setup` delay is completely new, and can help with cases where
asserting the CS, also brings the device out of power-sleep, where there
needs to be a longer (than usual), before transferring data.

The `cs_hold` time can overlap with the `delay` (or `delay_usecs`) from an
SPI transfer. The main difference is that `cs_hold` implies that CS will be
de-asserted.

The `cs_inactive` delay does not have a clear use-case yet. It has been
implemented mostly because the `spi_set_cs_timing()` function implements
it. To some degree, this could overlap or replace `cs_change_delay`, but
this will require more consideration/investigation in the future.

All these delays have been added to the `spi_controller` struct, as they
would typically be configured by calling `spi_set_cs_timing()` after an
`spi_setup()` call.

Software-mode for CS control, implies that the `set_cs_timing()` hook has
not been provided for the `spi_controller` object.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-16-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: tegra114: change format for `spi_set_cs_timing()` function

The initial version of `spi_set_cs_timing()` was implemented with
consideration only for clock-cycles as delay.

For cases like `CS setup` time, it's sometimes needed that micro-seconds
(or nano-seconds) are required, or sometimes even longer delays, for cases
where the device needs a little longer to start transferring that after CS
is asserted.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-15-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: introduce `delay` field for `spi_transfer` + spi_transfer_delay_exec()

The change introduces the `delay` field to the `spi_transfer` struct as an
`struct spi_delay` type.
This intends to eventually replace `delay_usecs`.

But, since there are many users of `delay_usecs`, this needs some
intermediate work.
A helper called `spi_transfer_delay_exec()` is also added, which maintains
backwards compatibility with `delay_usecs`, by assigning the value to
`delay` if non-zero.
This should maintain backwards compatibility with current users of
`udelay_usecs`.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-9-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core,atmel: convert `word_delay_usecs` -> `word_delay` for spi_device

This change does a conversion from the `word_delay_usecs` -> `word_delay`
for the `spi_device` struct.

This allows users to specify inter-word delays in other unit types
(nano-seconds or clock cycles), depending on how users want.

The Atmel SPI driver is the only current user of the `word_delay_usecs`
field (from the `spi_device` struct).
So, it needed a slight conversion to use the `word_delay` as an `spi_delay`
struct.

In SPI core, the only required mechanism is to update the `word_delay`
information per `spi_transfer`. This requires a bit more logic than before,
because it needs that both delays be converted to a common unit
(nano-seconds) for comparison.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-8-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: make `cs_change_delay` the first user of the `spi_delay` logic

Since the logic for `spi_delay` struct + `spi_delay_exec()` has been copied
from the `cs_change_delay` logic, it's natural to make this delay, the
first user.

The `cs_change_delay` logic requires that the default remain 10 uS, in case
it is unspecified/unconfigured. So, there is some special handling needed
to do that.

The ADIS library is one of the few users of the new `cs_change_delay`
parameter for an spi_transfer.

The introduction of the `spi_delay` struct, requires that the users of of
`cs_change_delay` get an update. This change also updates the ADIS library.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-4-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: introduce spi_delay struct as "value + unit" & spi_delay_exec()

There are plenty of delays that have been introduced in SPI core. Most of
them are in micro-seconds, some need to be in nano-seconds, and some in
clock-cycles.

For some of these delays (related to transfers & CS timing) it may make
sense to have a `spi_delay` struct that abstracts these a bit.

The important element of these delays [for unification] seems to be the
`unit` of the delay.
It looks like micro-seconds is good enough for most people, but every-once
in a while, some delays seem to require other units of measurement.

This change adds the `spi_delay` struct & a `spi_delay_exec()` function
that processes a `spi_delay` object/struct to execute the delay.
It's a copy of the `cs_change_delay` mechanism, but without the default
for 10 uS.

The clock-cycle delay unit is a bit special, as it needs to be bound to an
`spi_transfer` object to execute.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-3-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: move `cs_change_delay` backwards compat logic outside switch

The `cs_change_delay` backwards compatibility value could be moved outside
of the switch statement.
The only reason to do it, is to make the next patches easier to diff.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-2-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add a PTP system timestamp to the transfer structure

SPI is one of the interfaces used to access devices which have a POSIX
clock driver (real time clocks, 1588 timers etc). The fact that the SPI
bus is slow is not what the main problem is, but rather the fact that
drivers don't take a constant amount of time in transferring data over
SPI. When there is a high delay in the readout of time, there will be
uncertainty in the value that has been read out of the peripheral.
When that delay is constant, the uncertainty can at least be
approximated with a certain accuracy which is fine more often than not.

Timing jitter occurs all over in the kernel code, and is mainly caused
by having to let go of the CPU for various reasons such as preemption,
servicing interrupts, going to sleep, etc. Another major reason is CPU
dynamic frequency scaling.

It turns out that the problem of retrieving time from a SPI peripheral
with high accuracy can be solved by the use of "PTP system
timestamping" - a mechanism to correlate the time when the device has
snapshotted its internal time counter with the Linux system time at that
same moment. This is sufficient for having a precise time measurement -
it is not necessary for the whole SPI transfer to be transmitted "as
fast as possible", or "as low-jitter as possible". The system has to be
low-jitter for a very short amount of time to be effective.

This patch introduces a PTP system timestamping mechanism in struct
spi_transfer. This is to be used by SPI device drivers when they need to
know the exact time at which the underlying device's time was
snapshotted. More often than not, SPI peripherals have a very exact
timing for when their SPI-to-interconnect bridge issues a transaction
for snapshotting and reading the time register, and that will be
dependent on when the SPI-to-interconnect bridge figures out that this
is what it should do, aka as soon as it sees byte N of the SPI transfer.
Since spi_device drivers are the ones who'd know best how the peripheral
behaves in this regard, expose a mechanism in spi_transfer which allows
them to specify which word (or word range) from the transfer should be
timestamped.

Add a default implementation of the PTP system timestamping in the SPI
core. This is not going to be satisfactory performance-wise, but should
at least increase the likelihood that SPI device drivers will use PTP
system timestamping in the future.
There are 3 entry points from the core towards the SPI controller
drivers:

- transfer_one: The driver is passed individual spi_transfers to
execute. This is the easiest to timestamp.

- transfer_one_message: The core passes the driver an entire spi_message
(a potential batch of spi_transfers). The core puts the same pre and
post timestamp to all transfers within a message. This is not ideal,
but nothing better can be done by default anyway, since the core has
no insight into how the driver batches the transfers.

- transfer: Like transfer_one_message, but for unqueued drivers (i.e.
the driver implements its own queue scheduling).

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190905010114.26718-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add a PTP system timestamp to the transfer structure

SPI is one of the interfaces used to access devices which have a POSIX
clock driver (real time clocks, 1588 timers etc). The fact that the SPI
bus is slow is not what the main problem is, but rather the fact that
drivers don't take a constant amount of time in transferring data over
SPI. When there is a high delay in the readout of time, there will be
uncertainty in the value that has been read out of the peripheral.
When that delay is constant, the uncertainty can at least be
approximated with a certain accuracy which is fine more often than not.

Timing jitter occurs all over in the kernel code, and is mainly caused
by having to let go of the CPU for various reasons such as preemption,
servicing interrupts, going to sleep, etc. Another major reason is CPU
dynamic frequency scaling.

It turns out that the problem of retrieving time from a SPI peripheral
with high accuracy can be solved by the use of "PTP system
timestamping" - a mechanism to correlate the time when the device has
snapshotted its internal time counter with the Linux system time at that
same moment. This is sufficient for having a precise time measurement -
it is not necessary for the whole SPI transfer to be transmitted "as
fast as possible", or "as low-jitter as possible". The system has to be
low-jitter for a very short amount of time to be effective.

This patch introduces a PTP system timestamping mechanism in struct
spi_transfer. This is to be used by SPI device drivers when they need to
know the exact time at which the underlying device's time was
snapshotted. More often than not, SPI peripherals have a very exact
timing for when their SPI-to-interconnect bridge issues a transaction
for snapshotting and reading the time register, and that will be
dependent on when the SPI-to-interconnect bridge figures out that this
is what it should do, aka as soon as it sees byte N of the SPI transfer.
Since spi_device drivers are the ones who'd know best how the peripheral
behaves in this regard, expose a mechanism in spi_transfer which allows
them to specify which word (or word range) from the transfer should be
timestamped.

Add a default implementation of the PTP system timestamping in the SPI
core. This is not going to be satisfactory performance-wise, but should
at least increase the likelihood that SPI device drivers will use PTP
system timestamping in the future.
There are 3 entry points from the core towards the SPI controller
drivers:

- transfer_one: The driver is passed individual spi_transfers to
execute. This is the easiest to timestamp.

- transfer_one_message: The core passes the driver an entire spi_message
(a potential batch of spi_transfers). The core puts the same pre and
post timestamp to all transfers within a message. This is not ideal,
but nothing better can be done by default anyway, since the core has
no insight into how the driver batches the transfers.

- transfer: Like transfer_one_message, but for unqueued drivers (i.e.
the driver implements its own queue scheduling).

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190905010114.26718-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Guarantee cacheline alignment of driver-private data

__spi_alloc_controller() uses a single allocation to accommodate struct
spi_controller and the driver-private data, but places the latter behind
the former. This order does not guarantee cacheline alignment of the
driver-private data. (It does guarantee cacheline alignment of struct
spi_controller but the structure doesn't make any use of that property.)

Round up struct spi_controller to cacheline size. A forthcoming commit
leverages this to grant DMA access to driver-private data of the BCM2835
SPI master.

An alternative, less economical approach would be to use two allocations.

A third approach consists of reversing the order to conserve memory.
But Mark Brown is concerned that it may result in a performance penalty
on architectures that don't like unaligned accesses.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/01625b9b26b93417fb09d2c15ad02dfe9cdbbbe5.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use an abbreviated pointer to ctlr->cur_msg in __spi_pump_messages

This helps a bit with line fitting now (the list_first_entry call) as
well as during the next patch which needs to iterate through all
transfers of ctlr->cur_msg so it timestamps them.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190905010114.26718-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Rename of_spi_register_master() function

Rename this function to of_spi_get_gpio_numbers() as this
is what the function does, it does not register a master,
it is called in the path of registering a master so the
name is logical in a convoluted way, but it is better to
follow Rusty Russell's ABI level no 7:
"The obvious use is (probably) the correct one"

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190808150321.23319-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Reduce kthread priority

The SPI thingies request FIFO-99 by default, reduce this to FIFO-50.

FIFO-99 is the very highest priority available to SCHED_FIFO and
it not a suitable default; it would indicate the SPI work is the
most important work on the machine.

Cc: Benson Leung <bleung@chromium.org>
Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20190801111541.917256884@infradead.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: Use DEVICE_ATTR_RW() for SPI slave control sysfs attribute

Convert the SPI slave control sysfs attribute from DEVICE_ATTR() to
DEVICE_ATTR_RW(), to reduce boilerplate.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20190731124738.14519-1-geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers: Introduce device lookup variants by ACPI_COMPANION device

Add a generic helper to match a device by the ACPI_COMPANION device
and provide wrappers for the device lookup APIs.

Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: linux-i2c@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # I2C parts
Link: https://lore.kernel.org/r/20190723221838.12024-6-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: Introduce device lookup variants by of_node

Introduce wrappers for {bus/driver/class}_find_device() to
locate devices by its of_node.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: devicetree@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: linux-i2c@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-spi@vger.kernel.org
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alan Tull <atull@kernel.org>
Cc: linux-fpga@vger.kernel.org
Cc: Peter Rosin <peda@axentia.se>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Thor Thayer <thor.thayer@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Peter Rosin <peda@axentia.se>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # I2C part
Acked-by: Moritz Fischer <mdf@kernel.org> # For FPGA part
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20190723221838.12024-3-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi/acpi: avoid spurious matches during slave enumeration

In the new SPI ACPI slave enumeration code, we use the value of
lookup.max_speed_khz as a flag to decide whether a match occurred.
However, doing so only makes sense if we initialize its value to
zero beforehand, or otherwise, random junk from the stack will
cause spurious matches.

So zero initialize the lookup struct fully, and only set the non-zero
members explicitly.

Fixes: 4c3c59544f33 ("spi/acpi: enumerate all SPI slaves in the namespace")
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: andy.shevchenko@gmail.com
Cc: masahisa.kojima@linaro.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: linux-acpi@vger.kernel.org
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

bus_find_device: Unify the match callback with class_find_device

There is an arbitrary difference between the prototypes of
bus_find_device() and class_find_device() preventing their callers
from passing the same pair of data and match() arguments to both of
them, which is the const qualifier used in the prototype of
class_find_device(). If that qualifier is also used in the
bus_find_device() prototype, it will be possible to pass the same
match() callback function to both bus_find_device() and
class_find_device(), which will allow some optimizations to be made in
order to avoid code duplication going forward. Also with that, constify
the "data" parameter as it is passed as a const to the match function.

For this reason, change the prototype of bus_find_device() to match
the prototype of class_find_device() and adjust its callers to use the
const qualifier in accordance with the new prototype of it.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Kershner <david.kershner@unisys.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: David Airlie <airlied@linux.ie>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Sebastian Ott <sebott@linux.ibm.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Yehezkel Bernat <YehezkelShB@gmail.com>
Cc: rafael@kernel.org
Acked-by: Corey Minyard <minyard@acm.org>
Acked-by: David Kershner <david.kershner@unisys.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # for the I2C parts
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: fix ctrl->num_chipselect constraint

at91sam9g25ek showed the following error at probe:
atmel_spi f0000000.spi: Using dma0chan2 (tx) and dma0chan3 (rx)
for DMA transfers
atmel_spi: probe of f0000000.spi failed with error -22

Commit 0a919ae49223 ("spi: Don't call spi_get_gpio_descs() before device name is set")
moved the calling of spi_get_gpio_descs() after ctrl->dev is set,
but didn't move the !ctrl->num_chipselect check. When there are
chip selects in the device tree, the spi-atmel driver lets the
SPI core discover them when registering the SPI master.
The ctrl->num_chipselect is thus expected to be set by
spi_get_gpio_descs().

Move the !ctlr->num_chipselect after spi_get_gpio_descs() as it was
before the aforementioned commit. While touching this block, get rid
of the explicit comparison with 0 and update the commenting style.

Fixes: 0a919ae49223 ("spi: Don't call spi_get_gpio_descs() before device name is set")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi/acpi: fix incorrect ACPI parent check

The ACPI device object parsing code for SPI slaves enumerates the
entire ACPI namespace to look for devices that refer to the master
in question via the 'resource_source' field in the 'SPISerialBus'
resource. If that field does not refer to a valid ACPI device or
if it refers to the wrong SPI master, we should disregard the
device.

Current, the valid device check is wrong, since it gets the
polarity of 'status' wrong. This could cause issues if the
'resource_source' field is bogus but parent_handle happens to
refer to the correct master (which is not entirely imaginary
since this code runs in a loop)

So test for ACPI_FAILURE() instead, to make the code more
self explanatory.

Fixes: 4c3c59544f33 ("spi/acpi: enumerate all SPI slaves in the namespace")
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: andy.shevchenko@gmail.com
Cc: masahisa.kojima@linaro.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: linux-acpi@vger.kernel.org
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: don't open code list_for_each_entry_safe_reverse()

The loop declaration in function spi_res_release() can be simplified
by reusing the common list_for_each_entry_safe_reverse() helper
macro.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: No need to assign dummy value in spi_unregister_controller()

The device_for_each_child() doesn't require the returned value to be checked.
Thus, drop the dummy variable completely and have no warning anymore:

drivers/spi/spi.c: In function ‘spi_unregister_controller’:
drivers/spi/spi.c:2480:6: warning: variable ‘dummy’ set but not used [-Wunused-but-set-variable]
int dummy;
^~~~~

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi/acpi: enumerate all SPI slaves in the namespace

Currently, the ACPI enumeration that takes place when registering a
SPI master only considers immediate child devices in the ACPI namespace,
rather than checking the ResourceSource field in the SpiSerialBus()
resource descriptor.

This is incorrect: SPI slaves could reside anywhere in the ACPI
namespace, and so we should enumerate the entire namespace and look for
any device that refers to the newly registered SPI master in its
resource descriptor.

So refactor the existing code and use a lookup structure so that
allocating the SPI device structure is deferred until we have identified
the device as an actual child of the controller. This approach is
loosely based on the way the I2C subsystem handles ACPI enumeration.

Note that Apple x86 hardware does not rely on SpiSerialBus() resources
in _CRS but uses nested devices below the controller's device node in
the ACPI namespace, with a special set of device properties. This means
we have to take care to only parse those properties for device nodes
that are direct children of the controller node.

Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: linux-spi@vger.kernel.org
Cc: broonie@kernel.org
Cc: andy.shevchenko@gmail.com
Cc: masahisa.kojima@linaro.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: linux-acpi@vger.kernel.org
Cc: Lukas Wunner <lukas@wunner.de>

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use struct_size() helper

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct spi_replaced_transfers {
...
struct spi_transfer inserted_transfers[];
};

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

insert * sizeof(struct spi_transfer) + sizeof(struct spi_replaced_transfers)

with:

struct_size(rxfer, inserted_transfers, insert)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Allow SPI devices to request the pumping thread be realtime

Right now the only way to get the SPI pumping thread bumped up to
realtime priority is for the controller to request it. However it may
be that the controller works fine with the normal priority but
communication to a particular SPI device on the bus needs realtime
priority.

Let's add a way for devices to request realtime priority when they set
themselves up.

NOTE: this will just affect the priority of transfers that end up on
the SPI core's pumping thread. In many cases transfers happen in the
context of the caller so if you need realtime priority for all
transfers you should ensure the calling context is also realtime
priority.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: abort spi_sync if failed to prepare_transfer_hardware

There is no chance to wait spi message complete if failed to
prepare_transfer_hardware(). Therefore, finalize this message and abort
transfer with corresponding return status to release this block case.

Logs:

[17400.283005] c7 3267 PM: PM: suspend entry 2019-05-04 03:01:14.403097147 UTC
[17400.283013] c7 3267 PM: suspend entry (deep)
[17400.283016] c6 3267 PM: Syncing filesystems ... done.
[17400.584395] c1 753 spi_geni 890000.spi: spi_geni_prepare_transfer_hardware:Error enabling SE resources -13
[17400.584404] c1 753 spi_master spi1: failed to prepare transfer hardware
[17400.664611] c4 3267 PM: PM: suspend exit 2019-05-04 03:01:15.235273018 UTC

Flow:

__spi_sync@spi.c
| if (status == 0) {
| /* Push out the messages in the calling context if we
| * can.
| */
| if (ctlr->transfer == spi_queued_transfer) {
| SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
| spi_sync_immediate);
| SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
| spi_sync_immediate);
| __spi_pump_messages(ctlr, false);
| }
|
| wait_for_completion(&done); <== stuck here!!!
| status = message->status;
| }
| message->context = NULL;
| return status;
|
--> __spi_pump_messages@spi.c
| if (!was_busy && ctlr->prepare_transfer_hardware) {
| ret = ctlr->prepare_transfer_hardware(ctlr);
| if (ret) {
| dev_err(&ctlr->dev,
| "failed to prepare transfer hardware\n");
|
| if (ctlr->auto_runtime_pm)
| pm_runtime_put(ctlr->dev.parent);
| mutex_unlock(&ctlr->io_mutex);
| return;
| }
| }
|
--> spi_geni_prepare_transfer_hardware@spi-geni-qcom.c
| ret = pm_runtime_get_sync(mas->dev);
| if (ret < 0) {
| dev_err(mas->dev,
| "%s:Error enabling SE resources %d\n",
| __func__, ret);
| pm_runtime_put_noidle(mas->dev);
| goto exit_prepare_transfer_hardware;

Signed-off-by: Super Liu <supercjliu@google.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: allow reporting the effectivly used speed_hz for a transfer

Provide a means for the spi bus driver to report the effectively used
spi clock frequency used for each spi_transfer.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix Raspberry Pi breakage

This reverts commit c9ba7a16d0f1 (Release spi_res after finalizing
message) which causes races during cleanup.

Reported-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: allow defining time that cs is deasserted as a multiple of SCK

Support setting a delay between cs assert and deassert as
a multiple of spi clock length.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: core: allow defining time that cs is deasserted

For some SPI devices that support speed_hz > 1MHz the default 10 us delay
when cs_change = 1 is typically way to long and may result in poor spi bus
utilization.

This patch makes it possible to control the delay at micro or nano second
resolution on a per spi_transfer basis. It even allows an "as fast as
possible" mode with:
xfer.cs_change_delay_unit = SPI_DELAY_UNIT_NSECS;
xfer.cs_change_delay = 0;

The delay code is shared between delay_usecs and cs_change_delay for
consistency and reuse, so in the future this change_delay_unit could also
apply to delay_usec as well.

Note that on slower SOCs/CPU actually reaching ns deasserts on cs is not
realistic as the gpio overhead alone (without any delays added ) may
already leave cs deasserted for more than 1us - at least on a raspberry pi.
But at the very least this way we can keep it as short as possible.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Clear SPI_CS_HIGH flag from bad_bits for GPIO chip-select

When GPIO chip-select is used nothing prevents any available SPI
controllers to work with both CS-high and traditional CS-low modes.
In fact the SPI bus core code already does it, so we don't need to
introduce any modification there. But spi_setup() still fails to
switch the interface settings if CS-high flag is set for the case
of GPIO-driven slave chip-select when the SPI controller doesn't
support the hardwired CS-inversion. Lets fix it by clearing the
SPI_CS_HIGH flag out from bad_bits (unsupported by controller) when
client chip is selected by GPIO.

This feature is useful for slave devices, which in accordance with
communication protocol can work with both active-high and active-low
chip-selects. I am aware of one such device. It is MMC-SPI interface,
when at init sequence the driver needs to perform a read operation with
low and high chip-select sequentially (requirement of 74 clock cycles
with both chipselect, see the mmc_spi driver for details).

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Release spi_res after finalizing message

spi_split_transfers_maxsize() can be used to split a transfer. This
function uses spi_res to lifetime manage the added transfer structures.
So in order to finalize the current message while it contains the split
transfers, spi_res_release() must be called after finalizing.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove warning in spi_split_transfers_maxsize()

Don't warn about splitting transfers, the info is available in the
statistics if needed.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove one needless transfer speed fall back case

Falling back to maximum speed of the controller in case of SPI slave
maximum speed is not set is needless. It already defaults to maximum
speed of the controller since commit 052eb2d49006 ("spi: core: Set
max_speed_hz of spi_device default to max_speed_hz of controller").

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add a method for configuring CS timing

This patch creates set_cs_timing SPI master optional method for
SPI masters to implement configuring CS timing if applicable.

This patch also creates spi_cs_timing accessory for SPI clients to
use for requesting SPI master controllers to configure device requested
CS setup time, hold time and inactive delay.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: kill useless initializer in spi_register_controller()

The 'status' local variable is initialized but this value is never used,
thus kill that initializer.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Don't call spi_get_gpio_descs() before device name is set

Move code calling spi_get_gpio_descs() to happen after ctlr->dev's
name is set in order to have proper GPIO consumer names.

Before:

cat /sys/kernel/debug/gpio
gpiochip0: GPIOs 0-31, parent: platform/40049000.gpio, vf610-gpio:
gpio-6 ( |regulator-usb0-vbus ) out lo

gpiochip1: GPIOs 32-63, parent: platform/4004a000.gpio, vf610-gpio:
gpio-36 ( |scl ) in hi
gpio-37 ( |sda ) in hi
gpio-40 ( |(null) CS1 ) out lo
gpio-41 ( |(null) CS0 ) out lo ACTIVE LOW
gpio-42 ( |miso ) in hi
gpio-43 ( |mosi ) in lo
gpio-44 ( |sck ) out lo

After:

cat /sys/kernel/debug/gpio
gpiochip0: GPIOs 0-31, parent: platform/40049000.gpio, vf610-gpio:
gpio-6 ( |regulator-usb0-vbus ) out lo

gpiochip1: GPIOs 32-63, parent: platform/4004a000.gpio, vf610-gpio:
gpio-36 ( |scl ) in hi
gpio-37 ( |sda ) in hi
gpio-40 ( |spi0 CS1 ) out lo
gpio-41 ( |spi0 CS0 ) out lo ACTIVE LOW
gpio-42 ( |miso ) in hi
gpio-43 ( |mosi ) in lo
gpio-44 ( |sck ) out lo

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Chris Healy <cphealy@gmail.com>
Cc: linux-spi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add missing error handling for CS GPIOs

While devm_gpiod_get_index_optional() returns NULL if the GPIO is not
present (i.e. -ENOENT), it may still return other error codes, like
-EPROBE_DEFER. Currently these are not handled, leading to
unrecoverable failures later in case of probe deferral:

gpiod_set_consumer_name: invalid GPIO (errorpointer)
gpiod_direction_output: invalid GPIO (errorpointer)
gpiod_set_value_cansleep: invalid GPIO (errorpointer)
gpiod_set_value_cansleep: invalid GPIO (errorpointer)
gpiod_set_value_cansleep: invalid GPIO (errorpointer)

Detect and propagate errors to fix this.

Fixes: f3186dd876697e69 ("spi: Optionally use GPIO descriptors for CS GPIOs")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: export tracepoint symbols to modules

The newly added tracepoints in the spi-mxs driver cause a link
error when the driver is a loadable module:

ERROR: "__tracepoint_spi_transfer_stop" [drivers/spi/spi-mxs.ko] undefined!
ERROR: "__tracepoint_spi_transfer_start" [drivers/spi/spi-mxs.ko] undefined!

I'm not quite sure where to put the export statements, but
directly after the inclusion of the header seems as good as
any other place.

Fixes: f3fdea3af405 ("spi: mxs: add tracing to custom .transfer_one_message callback")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix zero length xfer bug

This fixes a bug for messages containing both zero length and
unidirectional xfers.

The function spi_map_msg will allocate dummy tx and/or rx buffers
for use with unidirectional transfers when the hardware can only do
a bidirectional transfer. That dummy buffer will be used in place
of a NULL buffer even when the xfer length is 0.

Then in the function __spi_map_msg, if he hardware can dma,
the zero length xfer will have spi_map_buf called on the dummy
buffer.

Eventually, __sg_alloc_table is called and returns -EINVAL
because nents == 0.

This fix prevents the error by not using the dummy buffer when
the xfer length is zero.

Signed-off-by: Chris Lesiak <chris.lesiak@licor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: use gpio[d]_set_value_cansleep for setting chipselect GPIO

Sleeping is safe inside spi_transfer_one_message, and some
GPIO chips are running on slow busses (such as I2C GPIO
expanders) and need to sleep for setting values.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: support inter-word delay requirement for devices

Some devices are slow and cannot keep up with the SPI bus and therefore
require a short delay between words of the SPI transfer.

The example of this that I'm looking at is a SAMA5D2 with a minimum SPI
clock of 400kHz talking to an AVR-based SPI slave. The AVR cannot put
bytes on the bus fast enough to keep up with the SoC's SPI controller
even at the lowest bus speed.

This patch introduces the ability to specify a required inter-word
delay for SPI devices. It is up to the controller driver to configure
itself accordingly in order to introduce the requested delay.

Note that, for spi_transfer, there is already a field word_delay that
provides similar functionality. This field, however, is specified in
clock cycles (and worse, SPI controller cycles, not SCK cycles); that
makes this value dependent on the master clock instead of the device
clock for which the delay is intended to provide some relief. This
patch leaves this old word_delay in place and provides a time-based
word_delay_us alongside it; the new field fits in the struct padding
so struct size is constant. There is only one in-kernel user of the
word_delay field and presumably that driver could be reworked to use
the time-based value instead.

The time-based delay is limited to 8 bits as these delays are intended
to be short. The SAMA5D2 that I've tested this on limits delays to a
maximum of ~100us, which is already many word-transfer periods even at
the minimum transfer speed supported by the controller.

Signed-off-by: Jonas Bonn <jonas@norrbonn.se>
CC: Mark Brown <broonie@kernel.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Mark Rutland <mark.rutland@arm.com>
CC: linux-spi@vger.kernel.org
CC: devicetree@vger.kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Support high CS when using descriptors

All controllers using GPIO descriptors can by definition
support high CS connections, so just enforce this when
registering an SPI controller.

This fixes a regression where controllers were missing
SPI_CS_HIGH, the drivers would fail like this:

spi spi0.0: setup: unsupported mode bits 4
cdns-spi fd0b0000.spi: can't setup spi0.0, status -22

This is because as using descriptors moves the CS inversion
logic over to gpiolib, all such controllers are registered
with CS active high.

Cc: Jan Kotas <jank@cadence.com>
Reported-by: Jan Kotas <jank@cadence.com>
Tested-by: Jan Kotas <jank@cadence.com>
Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Go back to immediate teardown

Commit 412e6037324 ("spi: core: avoid waking pump thread from spi_sync
instead run teardown delayed") introduced regressions on some boards,
apparently connected to spi_mem not triggering shutdown properly any
more. Since we've thus far been unable to figure out exactly where the
breakage is revert the optimisation for now.

Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: kernel@martin.sperl.org

spi: core: avoid waking pump thread from spi_sync instead run teardown delayed

When spi_sync is running alone with no other spi devices connected
to the bus the worker thread is woken during spi_finalize_current_message
to run the teardown code every time.

This is totally unnecessary in the case that there is no message queued.

On a multi-core system this results in one wakeup of the thread for each
spi_message processed via spi_sync where in most cases the teardown does
not happen as the hw is already in use.

This patch now delays the teardown by 1 second by using a separate
kthread_delayed_work for the teardown.

This avoids waking the kthread too often.

For spi_sync transfers in a tight loop (say 40k messages/s) this
avoids the penalty of waking the worker thread 40k times/s.
On a rasperry pi 3 with 4 cores the results in 32% of a single core
only to find out that there is nothing in the queue and it can go back
to sleep.

With this patch applied the spi-worker is woken exactly once: after
the load finishes and the spi bus is idle for 1 second.

I believe I have also seen situations where during a spi_sync loop
the worker thread (triggered by the last message finished) is slightly
faster and _wins_ the race to process the message, so we are actually
running the kthread and letting it do some work...

This is also no longer observed with this patch applied as.

Tested with a new CAN controller driver for the mcp2517fd which
uses spi_sync for interrupt handling and spi_async for scheduling
of can frames for transmission (in a different thread)

Some statistics when receiving 100000 CAN frames with the mcp25xxfd driver
on a Raspberry pi 3:

without the patch:
------------------
root@raspcm3:~# for x in $(pgrep spi0) $(pgrep irq/94-mcp25xxf) ; do awk '{printf "%-20s %6i\n", $2,$15}' /proc/$x/stat; done
(spi0) 5
(irq/94-mcp25xxf) 0
root@raspcm3:~# vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
1 0 0 821960 13592 50848 0 0 80 2 1986 105 1 2 97 0 0
0 0 0 821968 13592 50876 0 0 0 0 8046 30 0 0 100 0 0
0 0 0 821936 13592 50876 0 0 0 0 8032 24 0 0 100 0 0
0 0 0 821936 13592 50876 0 0 0 0 8035 30 0 0 100 0 0
0 0 0 821936 13592 50876 0 0 0 0 8033 22 0 0 100 0 0
2 0 0 821936 13592 50876 0 0 0 0 11598 7129 0 3 97 0 0
1 0 0 821872 13592 50876 0 0 0 0 37741 59003 0 31 69 0 0
2 0 0 821840 13592 50876 0 0 0 0 37762 59078 0 29 71 0 0
2 0 0 821776 13592 50876 0 0 0 0 37593 58792 0 28 72 0 0
1 0 0 821744 13592 50876 0 0 0 0 37642 58881 0 30 70 0 0
2 0 0 821680 13592 50876 0 0 0 0 37490 58602 0 27 73 0 0
1 0 0 821648 13592 50876 0 0 0 0 37412 58418 0 29 71 0 0
1 0 0 821584 13592 50876 0 0 0 0 37337 58288 0 27 73 0 0
1 0 0 821552 13592 50876 0 0 0 0 37584 58774 0 27 73 0 0
0 0 0 821520 13592 50876 0 0 0 0 18363 20566 0 9 91 0 0
0 0 0 821520 13592 50876 0 0 0 0 8037 32 0 0 100 0 0
0 0 0 821520 13592 50876 0 0 0 0 8031 23 0 0 100 0 0
0 0 0 821520 13592 50876 0 0 0 0 8034 26 0 0 100 0 0
0 0 0 821520 13592 50876 0 0 0 0 8033 24 0 0 100 0 0
^C
root@raspcm3:~# for x in $(pgrep spi0) $(pgrep irq/94-mcp25xxf) ; do awk '{printf "%-20s %6i\n", $2,$15}' /proc/$x/stat; done
(spi0) 228
(irq/94-mcp25xxf) 794
root@raspcm3:~# cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3
17: 34 0 0 0 ARMCTRL-level 1 Edge 3f00b880.mailbox
27: 1 0 0 0 ARMCTRL-level 35 Edge timer
33: 1416870 0 0 0 ARMCTRL-level 41 Edge 3f980000.usb, dwc2_hsotg:usb1
34: 1 0 0 0 ARMCTRL-level 42 Edge vc4
35: 0 0 0 0 ARMCTRL-level 43 Edge 3f004000.txp
40: 1753 0 0 0 ARMCTRL-level 48 Edge DMA IRQ
42: 11 0 0 0 ARMCTRL-level 50 Edge DMA IRQ
44: 11 0 0 0 ARMCTRL-level 52 Edge DMA IRQ
45: 0 0 0 0 ARMCTRL-level 53 Edge DMA IRQ
66: 0 0 0 0 ARMCTRL-level 74 Edge vc4 crtc
69: 0 0 0 0 ARMCTRL-level 77 Edge vc4 crtc
70: 0 0 0 0 ARMCTRL-level 78 Edge vc4 crtc
77: 20 0 0 0 ARMCTRL-level 85 Edge 3f205000.i2c, 3f804000.i2c, 3f805000.i2c
78: 6346 0 0 0 ARMCTRL-level 86 Edge 3f204000.spi
80: 205 0 0 0 ARMCTRL-level 88 Edge mmc0
81: 493 0 0 0 ARMCTRL-level 89 Edge uart-pl011
89: 0 0 0 0 bcm2836-timer 0 Edge arch_timer
90: 4291 3821 2180 1649 bcm2836-timer 1 Edge arch_timer
94: 14289 0 0 0 pinctrl-bcm2835 16 Level mcp25xxfd
IPI0: 0 0 0 0 CPU wakeup interrupts
IPI1: 0 0 0 0 Timer broadcast interrupts
IPI2: 3645 242371 7919 1328 Rescheduling interrupts
IPI3: 112 543 273 194 Function call interrupts
IPI4: 0 0 0 0 CPU stop interrupts
IPI5: 1 0 0 0 IRQ work interrupts
IPI6: 0 0 0 0 completion interrupts
Err: 0

top shows 93% for the mcp25xxfd interrupt handler, 31% for spi0.

with the patch:
---------------
root@raspcm3:~# for x in $(pgrep spi0) $(pgrep irq/94-mcp25xxf) ; do awk '{printf "%-20s %6i\n", $2,$15}' /proc/$x/stat; done
(spi0) 0
(irq/94-mcp25xxf) 0
root@raspcm3:~# vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
0 0 0 804768 13584 62628 0 0 0 0 8038 24 0 0 100 0 0
0 0 0 804768 13584 62628 0 0 0 0 8042 25 0 0 100 0 0
1 0 0 804704 13584 62628 0 0 0 0 9603 2967 0 20 80 0 0
1 0 0 804672 13584 62628 0 0 0 0 9828 3380 0 24 76 0 0
1 0 0 804608 13584 62628 0 0 0 0 9823 3375 0 23 77 0 0
1 0 0 804608 13584 62628 0 0 0 12 9829 3394 0 23 77 0 0
1 0 0 804544 13584 62628 0 0 0 0 9816 3362 0 22 78 0 0
1 0 0 804512 13584 62628 0 0 0 0 9817 3367 0 23 77 0 0
1 0 0 804448 13584 62628 0 0 0 0 9822 3370 0 22 78 0 0
1 0 0 804416 13584 62628 0 0 0 0 9815 3367 0 23 77 0 0
0 0 0 804352 13584 62628 0 0 0 84 9222 2250 0 14 86 0 0
0 0 0 804352 13592 62620 0 0 0 24 8131 209 0 0 93 7 0
0 0 0 804320 13592 62628 0 0 0 0 8041 27 0 0 100 0 0
0 0 0 804352 13592 62628 0 0 0 0 8040 26 0 0 100 0 0
root@raspcm3:~# for x in $(pgrep spi0) $(pgrep irq/94-mcp25xxf) ; do awk '{printf "%-20s %6i\n", $2,$15}' /proc/$x/stat; done
(spi0) 0
(irq/94-mcp25xxf) 767
root@raspcm3:~# cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3
17: 29 0 0 0 ARMCTRL-level 1 Edge 3f00b880.mailbox
27: 1 0 0 0 ARMCTRL-level 35 Edge timer
33: 1024412 0 0 0 ARMCTRL-level 41 Edge 3f980000.usb, dwc2_hsotg:usb1
34: 1 0 0 0 ARMCTRL-level 42 Edge vc4
35: 0 0 0 0 ARMCTRL-level 43 Edge 3f004000.txp
40: 1773 0 0 0 ARMCTRL-level 48 Edge DMA IRQ
42: 11 0 0 0 ARMCTRL-level 50 Edge DMA IRQ
44: 11 0 0 0 ARMCTRL-level 52 Edge DMA IRQ
45: 0 0 0 0 ARMCTRL-level 53 Edge DMA IRQ
66: 0 0 0 0 ARMCTRL-level 74 Edge vc4 crtc
69: 0 0 0 0 ARMCTRL-level 77 Edge vc4 crtc
70: 0 0 0 0 ARMCTRL-level 78 Edge vc4 crtc
77: 20 0 0 0 ARMCTRL-level 85 Edge 3f205000.i2c, 3f804000.i2c, 3f805000.i2c
78: 6417 0 0 0 ARMCTRL-level 86 Edge 3f204000.spi
80: 237 0 0 0 ARMCTRL-level 88 Edge mmc0
81: 489 0 0 0 ARMCTRL-level 89 Edge uart-pl011
89: 0 0 0 0 bcm2836-timer 0 Edge arch_timer
90: 4048 3704 2383 1892 bcm2836-timer 1 Edge arch_timer
94: 14287 0 0 0 pinctrl-bcm2835 16 Level mcp25xxfd
IPI0: 0 0 0 0 CPU wakeup interrupts
IPI1: 0 0 0 0 Timer broadcast interrupts
IPI2: 2361 2948 7890 1616 Rescheduling interrupts
IPI3: 65 617 301 166 Function call interrupts
IPI4: 0 0 0 0 CPU stop interrupts
IPI5: 1 0 0 0 IRQ work interrupts
IPI6: 0 0 0 0 completion interrupts
Err: 0
top shows 91% for the mcp25xxfd interrupt handler, 0% for spi0

So we see that spi0 is no longer getting scheduled wasting CPU cycles
There are a lot less context switches and corresponding Rescheduling interrupts
All of these show that this improves efficiency of the system and reduces
CPU utilization.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Optionally use GPIO descriptors for CS GPIOs

This augments the SPI core to optionally use GPIO descriptors
for chip select on a per-master-driver opt-in basis.

Drivers using this will rely on the SPI core to look up
GPIO descriptors associated with the device, such as
when using device tree or board files with GPIO descriptor
tables.

When getting descriptors from the device tree, this will in
turn activate the code in gpiolib that was
added in commit 6953c57ab172
("gpio: of: Handle SPI chipselect legacy bindings")
which means that these descriptors are aware of the active
low semantics that is the default for SPI CS GPIO lines
and we can assume that all of these are "active high" and
thus assign SPI_CS_HIGH to all CS lines on the DT path.

The previously used gpio_set_value() would call down into
gpiod_set_raw_value() and ignore the polarity inversion
semantics.

It seems like many drivers go to great lengths to set up the
CS GPIO line as non-asserted, respecting SPI_CS_HIGH. We pull
this out of the SPI drivers and into the core, and by simply
requesting the line as GPIOD_OUT_LOW when retrieveing it from
the device and relying on the gpiolib to handle any inversion
semantics. This way a lot of code can be simplified and
removed in each converted driver.

The end goal after dealing with each driver in turn, is to
delete the non-descriptor path (of_spi_register_master() for
example) and let the core deal with only descriptors.

The different SPI drivers have complex interactions with the
core so we cannot simply change them all over, we need to use
a stepwise, bisectable approach so that each driver can be
converted and fixed in isolation.

This patch has the intended side effect of adding support for
ACPI GPIOs as it starts relying on gpiod_get_*() to get
the GPIO handle associated with the device.

Cc: Linuxarm <linuxarm@huawei.com>
Acked-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Tested-by: Fangjian (Turing) <f.fangjian@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use of_node_name_eq for node name comparisons

Convert string compares of DT node names to use of_node_name_eq helper
instead. This removes direct access to the node name pointer.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add support for octal mode I/O data transfer

Add flags for Octal mode I/O data transfer
Required for the SPI controller which can do the data transfer (TX/RX)
on 8 data lines e.g. NXP FlexSPI controller.
SPI_TX_OCTAL: transmit with 8 wires
SPI_RX_OCTAL: receive with 8 wires

Signed-off-by: Yogesh Gaur <yogeshnarayan.gaur@nxp.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix formatting of header block

Make everything look intentional by having a C++ comment for the whole
block, not just the SPDX line.

Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix core transfer waits after slave support

The refactoring done as part of adding the core support for handling
waiting for slave transfer dropped a conditional which meant that we
started waiting for completion of all transfers, not just those that the
controller asked for. This caused hangs and massive delays on platforms
that don't need the core delay. Re-add the delay to fix this.

Fixes: 810923f3bf06c11 (spi: Deal with slaves that return from transfer_one() unfinished)
Reported-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Deal with slaves that return from transfer_one() unfinished

Some drivers, such as spi-pxa2xx return from the transfer_one callback
immediately, idicating that the transfer will be finished asynchronously.

Normally, spi_transfer_one_message() synchronously waits for the
transfer to finish with wait_for_completion_timeout(). For slaves, we
don't want the transaction to time out as it can complete in a long time
in future. Use wait_for_completion_interruptible() instead.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Make GPIO CSs honour the SPI_NO_CS flag

The SPI configuration state includes an SPI_NO_CS flag that disables
all CS line manipulation, for applications that want to manage their
own chip selects. However, this flag is ignored by the GPIO CS code
in the SPI framework.

Correct this omission with a trivial patch.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add driver_override SPI device attribute

This attribute works the same was as the identically named attribute
for PCI, AMBA, and platform devices. For reference, see:

commit 3cf385713460 ("ARM: 8256/1: driver coamba: add device binding
path 'driver_override'")
commit 3d713e0e382e ("driver core: platform: add device binding path
'driver_override'")
commit 782a985d7af2 ("PCI: Introduce new device binding path using
pci_dev.driver_override")

If the name of a driver is written to this attribute, then the device
will bind to the named driver and only the named driver.

The device will bind to the driver even if the driver does not list the
device in its id table. This behavior is different than the driver's
bind attribute, which only allows binding to devices that are listed as
supported by the driver.

It can be used to bind a generic driver, like spidev, to a device.

Signed-off-by: Trent Piepho <tpiepho@impinj.com>
Reviewed-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Tested-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: make OF helper available for others

The of_find_spi_device_by_node() helper function is useful for other
modules too. Export the funciton as GPL like all other spi helper
functions and make it available if CONFIG_OF is enabled, because it isn't
related to the CONFIG_OF_DYNAMIC context. Finally add a stub if
CONFIG_OF isn't enabled, so others must not care about it.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: switch to SPDX license identifier

Use the appropriate SPDX license identifier and drop the previous
license text.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: always use software fallback for SPI_CS_WORD when using cs_gio

This modifies the condition for using the software fallback
implementation for SPI_CS_WORD when the SPI controller is using a GPIO
for the CS line. When using a GPIO for CS, the hardware implementation
won't work, so we just enable the software fallback globally in this
case.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add software implementation for SPI_CS_WORD

This adds a default software implementation for the SPI_CS_WORD flag for
controllers that don't have such a feature.

The SPI_CS_WORD flag indicates that the CS line should be toggled
between each word sent, not just between each transfer. The
implementation works by using existing functions to split transfers into
one-word-sized transfers and sets the cs_change bit for each of the
new transfers.

Signed-off-by: David Lechner <david@lechnology.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix double IDR allocation with DT aliases

If the SPI bus number is provided by a DT alias, idr_alloc() is called
twice, leading to:

WARNING: CPU: 1 PID: 1 at drivers/spi/spi.c:2179 spi_register_controller+0x11c/0x5d8
couldn't get idr

Fix this by moving the handling of fixed SPI bus numbers up, before the
DT handling code fills in ctlr->bus_num.

Fixes: 1a4327fbf4554d5b ("spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers

On systems where some controllers get a dynamic ID assigned and some have
a fixed number (e.g. from ACPI tables), the current implementation might
run into an IDR collision: in case of a fixed bus number is gotten by a
driver (but not marked busy in IDR tree) and a driver with dynamic bus
number gets the same ID and predictably fails.

Fix this by means of checking-in fixed IDsin IDR as far as dynamic ones
at the moment of the controller registration.

Fixes: 9b61e302210e (spi: Pick spi bus number from Linux idr or spi alias)
Signed-off-by: Kirill Kapranov <kirill.kapranov@compulab.co.il>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

treewide: devm_kzalloc() -> devm_kcalloc()

The devm_kzalloc() function has a 2-factor argument form, devm_kcalloc().
This patch replaces cases of:

devm_kzalloc(handle, a * b, gfp)

with:
devm_kcalloc(handle, a * b, gfp)

as well as handling cases of:

devm_kzalloc(handle, a * b * c, gfp)

with:

devm_kzalloc(handle, array3_size(a, b, c), gfp)

as it's slightly less ugly than:

devm_kcalloc(handle, array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

devm_kzalloc(handle, 4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

Some manual whitespace fixes were needed in this patch, as Coccinelle
really liked to write "=devm_kcalloc..." instead of "= devm_kcalloc...".

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
expression HANDLE;
type TYPE;
expression THING, E;
@@

(
devm_kzalloc(HANDLE,
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
devm_kzalloc(HANDLE,
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression HANDLE;
expression COUNT;
typedef u8;
typedef __u8;
@@

(
devm_kzalloc(HANDLE,
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(__u8) * COUNT
+ COUNT
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(char) * COUNT
+ COUNT
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
expression HANDLE;
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(TYPE) * (COUNT_ID)
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(TYPE) * COUNT_ID
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(TYPE) * (COUNT_CONST)
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(TYPE) * COUNT_CONST
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(THING) * (COUNT_ID)
+ COUNT_ID, sizeof(THING)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(THING) * COUNT_ID
+ COUNT_ID, sizeof(THING)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(THING) * (COUNT_CONST)
+ COUNT_CONST, sizeof(THING)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(THING) * COUNT_CONST
+ COUNT_CONST, sizeof(THING)
, ...)
)

// 2-factor product, only identifiers.
@@
expression HANDLE;
identifier SIZE, COUNT;
@@

- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- SIZE * COUNT
+ COUNT, SIZE
, ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression HANDLE;
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
devm_kzalloc(HANDLE,
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression HANDLE;
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
devm_kzalloc(HANDLE,
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
devm_kzalloc(HANDLE,
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
expression HANDLE;
identifier STRIDE, SIZE, COUNT;
@@

(
devm_kzalloc(HANDLE,
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
devm_kzalloc(HANDLE,
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
devm_kzalloc(HANDLE,
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
devm_kzalloc(HANDLE,
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
devm_kzalloc(HANDLE,
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
devm_kzalloc(HANDLE,
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
devm_kzalloc(HANDLE,
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
devm_kzalloc(HANDLE,
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression HANDLE;
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
devm_kzalloc(HANDLE, C1 * C2 * C3, ...)
|
devm_kzalloc(HANDLE,
- (E1) * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
|
devm_kzalloc(HANDLE,
- (E1) * (E2) * E3
+ array3_size(E1, E2, E3)
, ...)
|
devm_kzalloc(HANDLE,
- (E1) * (E2) * (E3)
+ array3_size(E1, E2, E3)
, ...)
|
devm_kzalloc(HANDLE,
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression HANDLE;
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
devm_kzalloc(HANDLE, sizeof(THING) * C2, ...)
|
devm_kzalloc(HANDLE, sizeof(TYPE) * C2, ...)
|
devm_kzalloc(HANDLE, C1 * C2 * C3, ...)
|
devm_kzalloc(HANDLE, C1 * C2, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(TYPE) * (E2)
+ E2, sizeof(TYPE)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(TYPE) * E2
+ E2, sizeof(TYPE)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(THING) * (E2)
+ E2, sizeof(THING)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- sizeof(THING) * E2
+ E2, sizeof(THING)
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- (E1) * E2
+ E1, E2
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- (E1) * (E2)
+ E1, E2
, ...)
|
- devm_kzalloc
+ devm_kcalloc
(HANDLE,
- E1 * E2
+ E1, E2
, ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>