spi: axi-spi-engine: use struct_size() macro

This makes use of the struct_size() macro to calculate the size of the
struct axi_spi_engine when allocating it.

Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://msgid.link/r/20240304-mainline-axi-spi-engine-small-cleanups-v2-3-5b14ed729a31@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: use __counted_by() attribute

This adds the __counted_by() attribute to the flex array at the end of
struct spi_engine_program in the AXI SPI Engine controller driver.

The assignment of the length field has to be reordered to be before
the access to the flex array in order to avoid potential compiler
warnings/errors due to adding the __counted_by() attribute.

Suggested-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://msgid.link/r/20240304-mainline-axi-spi-engine-small-cleanups-v2-2-5b14ed729a31@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: remove p from struct spi_engine_message_state

The program pointer p in struct spi_engine_message_state in the AXI SPI
Engine controller driver was assigned but never read so it can be
removed.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://msgid.link/r/20240304-mainline-axi-spi-engine-small-cleanups-v2-1-5b14ed729a31@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: move message compile to optimize_message

In the AXI SPI Engine driver, compiling the message is an expensive
operation. Previously, it was done per message transfer in the
prepare_message hook. This patch moves the message compile to the
optimize_message hook so that it is only done once per message in
cases where the peripheral driver calls spi_optimize_message().

This can be a significant performance improvement for some peripherals.
For example, the ad7380 driver saw a 13% improvement in throughput
when using the AXI SPI Engine driver with this patch.

Since we now need two message states, one for the optimization stage
that doesn't change for the lifetime of the message and one that is
reset on each transfer for managing the current transfer state, the old
msg->state is split into msg->opt_state and spi_engine->msg_state. The
latter is included in the driver struct now since there is only one
current message at a time that can ever use it and it is in a hot path
so avoiding allocating a new one on each message transfer saves a few
cpu cycles and lets us get rid of the prepare_message callback.

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

spi: axi-spi-engine: move msg finalization out of irq handler

As a general principal, it is best to do as little as possible in an
interrupt handler. This patch reworks the AXI SPI Engine driver to move
timer_delete_sync() and spi_finalize_current_message() out of the
interrupt handler. Instead, spi_finalize_current_message() is moved to
the transfer_one_message function (similar to nearly all other SPI
controllers). A completion is now used to wait for the sync interrupt
that indicates that the message is complete. The watchdog timer is no
longer needed since we can use the wait_for_completion_timeout()
function to wait for the message to complete with the same effect.

As a bonus, these changes also improve throughput of the SPI controller.
For example, this was tested on a ZynqMP with a 80MHz SCLK reading 4
byte samples from an ADC. The max measured throughput increased from
26k to 28k samples per second.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240207-axi-spi-engine-round-2-1-v2-2-40c0b4e85352@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: remove use of ida for sync id

Profiling has shown that ida_alloc_range() accounts for about 10% of the
time spent in spi_sync() when using the AXI SPI Engine controller. This
call is used to create a unique id for each SPI message to match to an
IRQ when the message is complete.

Since the core SPI code serializes messages in a message queue, we can
only have one message in flight at a time, namely host->cur_msg. This
means that we can use a fixed value instead of a unique id for each
message since there can never be more than one message pending at a
time.

This patch removes the use of ida for the sync id and replaces it with a
constant value. This simplifies the driver and improves performance.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240207-axi-spi-engine-round-2-1-v2-1-40c0b4e85352@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: use common AXI macros

This avoid duplicating the same macros in multiple drivers by reusing
the common AXI macros for the version register.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240202213132.3863124-2-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: fix struct member doc warnings

The build bots are complaining that the members of struct
spi_engine_message_state are not described. This adds the
proper @name: syntax to the comments to fix this.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312182101.QOWovo29-lkp@intel.com/
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://msgid.link/r/20231218145348.339470-1-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: add watchdog timer

If there is an issue with the AXI SPI Engine hardware a scheduled
transfer might never be completed and spi_sync() will block forever.
This due to the uninterruptible wait for completion waiting for the
spi_finalize_current_message() that never comes.

Add a watchdog timer that will abort a transfer 5 seconds after it has
been started. This will potentially leave the hardware in a broken state
but it allows software to recover and allow to better diagnose the
underlying issue.

Co-developed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-9-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: remove delay from CS assertion

Now that the AXI SPI Engine driver has support for the various CS delays
requested through struct spi_message, we don't need to add a separate
delay to the CS assertion instruction. Otherwise, we end up with longer
than requested delays.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-8-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: restore clkdiv at end of message

This modifies the ADI AXI SPI Engine driver to restore the clkdiv
configuration register at the end of a SPI message. Having the clkdiv in
a known state is needed to be able to add a new command in the future
that only performs a delay without any SPI transfers. Furthermore having
that state be the smallest possible divider will allow these delays to
have the highest possible precision.

Changing the initial value of clk_div from -1 to 1 is now possible
because we know the function will always be called with a known clkdiv
config register state. Making this change will also have the effect of
not emitting a clkdiv configuration register instruction in cases where
the maximum sclk rate is used. Having one less instruction to process
reduces delays on the bus which will be beneficial when we implement
offload support to enable reading data from devices at very high rates.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-7-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: implement xfer->cs_change_delay

This adds handling of xfer->cs_change_delay to the AXI SPI Engine
driver.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-6-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: remove xfer arg from spi_engine_gen_sleep()

This replaces the xfer parameter of spi_engine_gen_sleep() in the AXI
SPI Engine driver with parameters for the delay in nanoseconds and the
SPI SCLK rate. This will allow this function to be used by callers in
the future that do not have a spi_transfer struct.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-5-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: fix sleep ticks calculation

This fixes the sleep ticks calculation when generating sleep
instructions in the AXI SPI Engine driver. The previous calculation
was ignoring delays less than one microsecond and missed a microsecond
to second conversion factor.

This fixes the first issue by not rounding to microseconds. Now that
xfer->effective_speed_hz is guaranteed to be set correctly, we can use
that to simplify the calculation. This new calculation replaces the old
incorrect math.

Also add unit suffix to the delay variable for clarity while we are
touching this.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-4-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: remove spi_engine_get_clk_div()

Now that host->max_speed_hz and xfer->effective_speed_hz are properly
set, we can use them instead of having to do more complex calculations
to get the clock divider for each transfer.

This removes the spi_engine_get_clk_div() function and replaces it with
just dividing the two clock rates. Since the hardware register value is
the divider minus one, we need to subtract one. Subtracting one was
previously done in the spi_engine_get_clk_div() function.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-3-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: populate xfer->effective_speed_hz

This adds a new spi_engine_precompile_message() function to the ADI AXI
SPI Engine driver to populate the xfer->effective_speed_hz field since
the SPI core doesn't/can't do this for us.

This driver is already using spi_delay_to_ns() which depends on
effective_speed_hz to get an accurate value in some cases.
Having an effective_speed_hz value can also be used in future changes
to simplify other code.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-2-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: return void from spi_engine_compile_message()

In the AXI SPI Engine driver, the spi_engine_compile_message() function
does not return any error and none of the callers check the return
value. So we can change the return type to void and drop the return 0.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-1-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: add support for any word size

The AXI SPI Engine IP supports any word size from 1 to 32 bits. This
adds support for this by setting the bits_per_word_mask and emitting
the appropriate instruction to the SPI Engine each time a transfer
requires a new word size.

The functions that transfer tx/rx buffers from/to the SPI Engine
registers (spi_engine_write_{tx,rx}_fifo()) as well as the function that
creates the transfer instruction (spi_engine_gen_xfer()) also have to be
modified to take into account the word size since xfer->len is the
size of the buffers in bytes rather than words.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-14-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: add support for cs_off

This adds support for the spi_transfer::cs_off flag to the AXI SPI
Engine driver.

The logic is copied from the generic spi_transfer_one_message() in
spi.c.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-13-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: remove struct spi_engine::msg

In the AXI SPI Engine driver, the struct spi_engine::msg member was used
to keep track of the current message being processed. The SPI core is
already keeping track of this, so we don't need to duplicate the effort.

In most cases, we already have a pointer to the current message, so we
can pass it directly to the functions that need it. In the one case
where we don't have a pointer to the current message, we can get it
from struct spi_controller::cur_msg.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-12-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: remove completed_id from driver state

In the AXI SPI Engine driver, the completed_id field in the driver
state is only used in one function and the value does not need to
persist between function calls. Therefore, it can be removed from the
driver state and made a local variable in the function where it is used.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-11-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: use message_prepare/unprepare

This modifies the AXI SPI Engine driver to make use of the
message_prepare and message_unprepare callbacks. This separates
the concerns of allocating and freeing the message state from the
transfer_one_message callback.

The main benfit of this is so that future callers of
spi_finalize_current_message() will not have to do manual cleanup
of the state.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-10-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: move msg state to new struct

This moves the message state in the AXI SPI Engine driver to a new
struct spi_engine_msg_state.

Previously, the driver state contained various pointers that pointed
to memory owned by a struct spi_message. However, it did not set any of
these pointers to NULL when a message was completed. This could lead to
use after free bugs.

Example of how this could happen:
1. SPI core calls into spi_engine_transfer_one_message() with msg1.
2. Assume something was misconfigured and spi_engine_tx_next() is not
called enough times in interrupt callbacks for msg1 such that
spi_engine->tx_xfer is never set to NULL before the msg1 completes.
3. SYNC interrupt is received and spi_finalize_current_message() is
called for msg1. spi_engine->msg is set to NULL but no other
message-specific state is reset.
4. Caller that sent msg1 is notified of the completion and frees msg1
and the associated xfers and tx/rx buffers.
4. SPI core calls into spi_engine_transfer_one_message() with msg2.
5. When spi_engine_tx_next() is called for msg2, spi_engine->tx_xfer is
still be pointing to an xfer from msg1, which was already freed.
spi_engine_xfer_next() tries to access xfer->transfer_list of one
of the freed xfers and we get a segfault or undefined behavior.

To avoid issues like this, instead of putting per-message state in the
driver state struct, we can make use of the struct spi_message::state
field to store a pointer to a new struct spi_engine_msg_state. This way,
all of the state that belongs to specific message stays with that
message and we don't have to remember to manually reset all aspects of
the message state when a message is completed. Rather, a new state is
allocated for each message.

Most of the changes are just renames where the state is accessed. One
place where this wasn't straightforward was the sync_id member. This
has been changed to use ida_alloc_range() since we needed to separate
the per-message sync_id from the per-controller next available sync_id.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-9-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: check for valid clock rate

This adds a check for a valid SCLK rate in the axi-spi-engine driver
during probe. A valid rate is required to get accurate timing for delays
and by not allowing 0 we can avoid divide by zero errors later without
additional checks.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-8-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: use devm_spi_register_controller()

This replaces spi_register_controller() with
devm_spi_register_controller() in the AXI SPI Engine driver. This
saves us from having to call spi_unregister_controller() in the
remove function.

The remove function is also removed since it is no longer needed.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-7-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: use devm_request_irq()

This replaces request_irq() with devm_request_irq() in the AXI SPI
Engine driver. This simplifies the error path and removes the need to
call free_irq() in the remove function.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-6-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: use devm action to reset hw on remove

This moves the reset of the hardware to a devm action in the AXI SPI
Engine driver. This will allow us to use devm on later calls in the
probe function while preserving the order during cleanup.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-5-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: use devm_spi_alloc_host()

This modifies the AXI SPI Engine driver to use devm_spi_alloc_host()
instead of spi_alloc_host() to simplify the code a bit.

In addition to simplifying the error paths in the probe function, we
can also remove spi_controller_get/put() calls in the remove function
since devm_spi_alloc_host() sets a flag to no longer decrement the
controller reference count in the spi_unregister_controller() function.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-4-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: simplify driver data allocation

This simplifies the private data allocation in the AXI SPI Engine driver
by making use of the feature built into the spi_alloc_host() function
instead of doing it manually.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231117-axi-spi-engine-series-1-v1-3-cc59db999b87@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi-spi-engine: Use helper function devm_clk_get_enabled()

Since commit 7ef9651e9792 ("clk: Provide new devm_clk helpers for prepared
and enabled clocks"), devm_clk_get() and clk_prepare_enable() can now be
replaced by devm_clk_get_enabled() when driver enables (and possibly
prepares) the clocks for the whole lifetime of the device. Moreover, it is
no longer necessary to unprepare and disable the clocks explicitly.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Link: https://lore.kernel.org/r/20230823133938.1359106-6-lizetao1@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Do not check for 0 return after calling platform_get_irq()

It is not possible for platform_get_irq() to return 0. Use the
return value from platform_get_irq().

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com> #
Link: https://lore.kernel.org/r/20230802093238.975906-1-ruanjinjie@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi-spi-engine: switch to use modern name

Change legacy name master to modern name host or controller.

No functional changed.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20230728093221.3312026-4-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Replace all spi->chip_select and spi->cs_gpiod references with function call

Supporting multi-cs in spi 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 with get or set 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.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
Acked-by: Heiko Stuebner <heiko@sntech.de> # Rockchip drivers
Reviewed-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org> # Aspeed driver
Reviewed-by: Dhruva Gole <d-gole@ti.com> # SPI Cadence QSPI
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> # spi-stm32-qspi
Acked-by: William Zhang <william.zhang@broadcom.com> # bcm63xx-hsspi driver
Reviewed-by: Serge Semin <fancer.lancer@gmail.com> # DW SSI part
Link: https://lore.kernel.org/r/167847070432.26.15076794204368669839@mailman-core.alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: axi-spi-engine: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230303172041.2103336-9-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi-spi-engine: remove usage of delay_usecs

The 'delay_usecs' field was handled for backwards compatibility in case
there were some users that still configured SPI delay transfers with
this field.

They should all be removed by now.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210308145502.1075689-2-aardelean@deviqon.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi-spi-engine: Access register after clock initialization

Move register access after clock initialization.
Clock "s_axi_aclk" is needed for register access. Without the clock running
AXI bus hangs and causes kernel freeze.

Signed-off-by: Rafał Hibner <rafal.hibner@secom.com.pl>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20200409155621.12174-1-rafal.hibner@secom.com.pl
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi: extend support for the `delay` field

The AXI SPI engine driver uses the `delay_usecs` field from `spi_transfer`
to configure delays, which the controller will execute.
This change extends the logic to also include the `delay` value, in case it
is used (instead if `delay_usecs`).

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-20-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-5-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 177

Based on 1 normalized pattern(s):

licensed under the gpl 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 135 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.071193225@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: spi-axi: fix potential use-after-free after deregistration

Take an extra reference to the controller before deregistering it to
prevent use-after-free in the interrupt handler in case an interrupt
fires before the line is disabled.

Fixes: b1353d1c1d45 ("spi: Add Analog Devices AXI SPI Engine controller support")
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi: Free resources on error path

We should go to 'err_put_master' here instead of returning directly.
Otherwise a call to 'spi_master_put' is missing.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi: Fix module autoload

If the driver is built as a module, autoload won't work because the module
alias information is not filled. So user-space can't match the registered
device with the corresponding module.

Export the module alias information using the MODULE_DEVICE_TABLE() macro.

Before this patch:

$ modinfo drivers/spi/spi-axi-spi-engine.ko | grep alias
$

After this patch:

$ modinfo drivers/spi/spi-axi-spi-engine.ko | grep alias
alias: of:N*T*Cadi,axi-spi-engine-1.00.aC*
alias: of:N*T*Cadi,axi-spi-engine-1.00.a

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Drop duplicate code to set master->dev.parent

It's done by spi_alloc_master().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add Analog Devices AXI SPI Engine controller support

This patch adds support for the AXI SPI Engine controller which is a FPGA
soft-peripheral which is used in some of Analog Devices' reference designs.

The AXI SPI Engine controller is part of the SPI Engine framework[1] and
allows memory mapped access to the SPI Engine control bus. This allows it
to be used as a general purpose software driven SPI controller. The SPI
Engine in addition offers some optional advanced acceleration and
offloading capabilities, which are not part of this patch though and will
be introduced separately.

At the core of the SPI Engine framework is a small sort of co-processor
that accepts a command stream and turns the commands into low-level SPI
transactions. Communication is done through three memory mapped FIFOs in
the register map of the AXI SPI Engine peripheral. One FIFO for the command
stream and one each for transmit and receive data.

The driver translates a spi_message in a command stream and writes it to
the peripheral which executes it asynchronously. This allows it to perform
very precise timings which are required for some SPI slave devices to
achieve maximum performance (e.g. analog-to-digital and digital-to-analog
converters). The execution flow is synchronized to the host system by a
special synchronize instruction which generates a interrupt.

[1] https://wiki.analog.com/resources/fpga/peripherals/spi_engine

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>