spi: stm32: move splitting transfers to optimize_message

Since splitting transfers was moved to spi_optimize_message() in the
core SPI code, we now need to use the optimize_message callback in the
STM32 SPI driver to ensure that the operation is only performed once
when spi_optimize_message() is used by peripheral drivers explicitly.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://msgid.link/r/20240219-mainline-spi-precook-message-v2-3-4a762c6701b9@baylibre.com
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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: stm32: add st,stm32mp25-spi compatible supporting STM32MP25 soc

Add support for the STM32MP25:
- Burst should not be enabled with the new DMA used on STM32MP25.
- STM32MP25 SPI8 has a limited feature set, it can only send words of
8 or 16 bits and with a maximum words number of 1024.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://msgid.link/r/20231218155721.359198-4-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: use dma_get_slave_caps prior to configuring dma channel

First check the dma channel capabilities (max burst) before
configuring the dma channel.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://msgid.link/r/20231218155721.359198-2-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: switch to use modern name

Change legacy name master/slave to modern name host/target.

No functional changed.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://msgid.link/r/20231128093031.3707034-6-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: add STM32F7 support

The STM32F7 SPI peripheral is similar to the STM32F4, except it allows
arbitrary word lengths between 4 and 16 bits, and has a small 32-bit
FIFO that allows two 8-bit or smaller words to be transferred with a
single 16-bit read/write.

Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Link: https://lore.kernel.org/r/20231102193722.3042245-5-ben.wolsieffer@hefring.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: use callbacks for read_rx and write_tx

The STM32F7 will require different read and write routines, so make
these functions into configurable callbacks.

Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Link: https://lore.kernel.org/r/20231102193722.3042245-3-ben.wolsieffer@hefring.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: rename stm32f4_* to stm32fx_*

The STM32F4 and STM32F7 SPI peripherals are very similar, therefore
most of the driver can be shared between the two. In preparation for
adding support for the F7, change all functions and defines to use a
generic stm32fx prefix, except for code and registers that differ
between the two devices.

Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Link: https://lore.kernel.org/r/20231102193722.3042245-2-ben.wolsieffer@hefring.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it was merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Acked-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20231017203352.2698326-1-robh@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: add a delay before SPI disable

As explained in errata sheet, in section "2.14.5 Truncation of SPI output
signals after EOT event":
On STM32MP1x, EOT interrupt can be thrown before the true end of
communication.

So we add a delay of a half period to wait the real end of the
transmission.

Link: https://www.st.com/resource/en/errata_sheet/es0539-stm32mp131x3x5x-device-errata-stmicroelectronics.pdf
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20230906132735.748174-1-valentin.caron@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Remove redundant dev_err_probe()

There is no need to call the dev_err_probe() function directly to print
a custom message when handling an error from platform_get_irq() function as
it is going to display an appropriate error message in case of a failure.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20230727110558.2904084-1-ruanjinjie@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Get rid of old SPI_MASTER_MUST_TX & SPI_MASTER_MUST_RX

Convert the users from SPI_MASTER_MUST_TX and/or SPI_MASTER_MUST_RX
to SPI_CONTROLLER_MUST_TX and/or SPI_CONTROLLER_MUST_RX respectively
and kill the not used anymore definitions.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-13-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: disable device mode with st,stm32f4-spi compatible

STM32 SPI driver is not capable to handle device mode with stm32f4 soc.
Stop probing if this case happens.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20230706081342.468090-1-valentin.caron@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix accidential revert to byte-sized transfer splitting

Commit 6f486556abe35 ("spi: stm32: renaming of spi_master into
spi_controller") included an accidential reverted of a change added in
commit 1e4929112507f ("spi: stm32: split large transfers based on word
size instead of bytes").

This breaks large SPI transfers with word sizes > 8 bits, which are
e.g. common when driving MIPI DBI displays.

Fix this by using `spi_split_transfers_maxwords()` instead of
`spi_split_transfers_maxsize()`.

Fixes: 6f486556abe35 ("spi: stm32: renaming of spi_master into spi_controller")
Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
Link: https://lore.kernel.org/r/20230816145237.3159817-1-l.goehrs@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: introduction of stm32h7 SPI device mode support

Add support for stm32h7 to use SPI controller in device role.
In such case, the spi instance should have the spi-slave property
defined.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20230615075815.310261-5-valentin.caron@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: use dmaengine_terminate_{a}sync instead of _all

Avoid usage of deprecated dmaengine_terminate_all and use
dmaengine_terminate_sync and dmaengine_terminate_async instead.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20230615075815.310261-3-valentin.caron@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: renaming of spi_master into spi_controller

Preparing introduction of SPI device, rename the spi_master structure
into spi_controller. This doesn't have any functional impact since
spi_master was already a macro for spi_controller.
Referring now to ctrl instead of master since the spi_controller
structure might not be used as a master controller only.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20230615075815.310261-2-valentin.caron@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Use devm_platform_get_and_ioremap_resource()

According to commit 890cc39a8799 ("drivers: provide
devm_platform_get_and_ioremap_resource()"), convert
platform_get_resource(), devm_ioremap_resource() to a single
call to devm_platform_get_and_ioremap_resource(), as this is exactly
what this function does.

Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230328061839.82185-1-yang.lee@linux.alibaba.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: split large transfers based on word size instead of bytes

The TSIZE register in CR2, to which the number of words to transfer
is written, is only 16 Bit. This limits transfers to 65535 SPI
_words_ at a time. The existing code uses spi_split_transfers_maxsize
to limit transfers to 65535 _bytes_ at a time.

This breaks large transfers with bits_per_word > 8, as they are
split inside of a word boundary by the odd size limit.

Split transfers based on the number of words instead.
This has the added benefit of not artificially limiting the maximum
length of bpw > 8 transfers to half or a quarter of the actual limit.

The combination of very large transfers and bits_per_word = 16 is triggered
e.g. by MIPI DBI displays when updating large parts of the screen.

Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
Acked-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/20230310092053.1006459-2-l.goehrs@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: 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/20230303172041.2103336-74-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix stm32_spi_prepare_mbr() that halves spi clk for every run

When this driver is used with a driver that uses preallocated spi_transfer
structs. The speed_hz is halved by every run. This results in:

spi_stm32 44004000.spi: SPI transfer setup failed
ads7846 spi0.0: SPI transfer failed: -22

Example when running with DIV_ROUND_UP():
- First run; speed_hz = 1000000, spi->clk_rate 125000000
div 125 -> mbrdiv = 7, cur_speed = 976562
- Second run; speed_hz = 976562
div 128,00007 (roundup to 129) -> mbrdiv = 8, cur_speed = 488281
- Third run; speed_hz = 488281
div 256,000131072067109 (roundup to 257) and then -EINVAL is returned.

Use DIV_ROUND_CLOSEST to allow to round down and allow us to keep the
set speed.

Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Link: https://lore.kernel.org/r/20221103080043.3033414-1-sean@geanix.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Print summary 'callbacks suppressed' message

The original fix "spi: stm32: Rate-limit the 'Communication suspended' message"
still leads to "stm32h7_spi_irq_thread: 1696 callbacks suppressed" spew in the
kernel log. Since this 'Communication suspended' message is a debug print, add
RATELIMIT_MSG_ON_RELEASE flag to inhibit the "callbacks suspended" part during
normal operation and only print summary at the end.

Fixes: ea8be08cc9358 ("spi: stm32: Rate-limit the 'Communication suspended' message")
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20221018183513.206706-1-marex@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: using pm_runtime_resume_and_get instead of pm_runtime_get_sync

Using pm_runtime_resume_and_get() to replace pm_runtime_get_sync and
pm_runtime_put_noidle. This change is just to simplify the code, no
actual functional changes.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Link: https://lore.kernel.org/r/20220420090452.2588930-1-chi.minghao@zte.com.cn
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: ignore Rx queue not empty in stm32f4 Tx only mode

STM32F4_SPI_SR_RXNE and STM32F4_SPI_SR_OVR are distinct bits in the same
status register. ~STM32F4_SPI_SR_OVR | STM32F4_SPI_SR_RXNE is thus
equal to ~STM32F4_SPI_SR_OVR.

The original intention was likely for transmission-only transfers to
ignore interrupts both for when the Rx queue has bytes (RXNE) as well
as when these bytes haven't been read in time (OVR).

Fix the typo by adding the missing parenthesis.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.kernel.org/r/20220201115142.3999860-1-a.fatoum@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: make SPI_MASTER_MUST_TX flags only specific to STM32F4

Commit 61367d0b8f5e ("spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4")
allowed to properly communicate with the st-gyro-spi even when
there is no tx_buf provided by setting the flag SPI_MASTER_MUST_TX and
thus forcing a dummy TX buffer to work in Full Duplex.
This behavior should kept only for the STM32F4 and not for other
compatible since the STM32H7 do support SIMPLEX_RX and SIMPLEX_TX.
Add the flags variable within the struct stm32_spi_cfg so that flags
used at master registration time are compatible specific.

Fixes: 61367d0b8f5e ("spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4")

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/20220119093245.624878-3-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: remove inexistant variables in struct stm32_spi_cfg comment

Variables 'can_dma' and 'has_startbit' are described within the
struct stm32_spi_cfg comment but have never existed in this structure
so remove them.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/20220119093245.624878-2-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix excluded_middle.cocci warnings

drivers/spi/spi-stm32.c:915:23-25: WARNING !A || A && B is equivalent to !A || B

Condition !A || A && B is equivalent to !A || B.

Generated by: scripts/coccinelle/misc/excluded_middle.cocci

Fixes: 7ceb0b8a3ced ("spi: stm32: finalize message either on dma callback or EOT")
CC: Alain Volmat <alain.volmat@foss.st.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Reviewed-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/20210713191004.GA14729@5eb5c2cbef84
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: finalize message either on dma callback or EOT

Depending on the usage, it is necessary to perform the finalize
message operation either upon receiving the EOT interruption,
eiher upon receiving the DMA callback. Indeed, when relying
on DMA, even if the SPI EOT IT has been received, it is
necessary to wait for the end of the DMA RX transaction before
accessing to the data.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1625646426-5826-8-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32h7: don't wait for EOT and flush fifo on disable

In nominal cases, disable is called as part of the unprepare_message,
after receiving a EOT and after receiving all data so it doesn't
make sense to check for EOT and empty the FIFO.
Moreover, at the end of the disable, the SPI is disable (SPE) leading
to clear of all internal FIFO, leaving the IP in a known status.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1625646426-5826-7-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32h7: rework rx fifo read function

Remove flush parameter and check RXWNE or RXPLVL when end of transfer
flag is set.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1625646426-5826-6-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Revert "properly handle 0 byte transfer"

0 byte transfer handling is now done within the core in code added
by commit b306320322c9 ("spi: Skip zero-length transfers in spi_transfer_one_message()")

This reverts commit 2269f5a8b1a7 ("spi: stm32: properly handle 0 byte transfer")

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1625646426-5826-5-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: enable pm_runtime autosuspend

This commit enables the pm_runtime autosuspend
and sets a 1ms autosuspend delay.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1625646426-5826-3-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fixes pm_runtime calls in probe/remove

Add pm_runtime calls in probe/probe error path and remove
in order to be consistent in all places in ordering and
ensure that pm_runtime is disabled prior to resources used
by the SPI controller.

This patch also fixes the 2 following warnings on driver remove:
WARNING: CPU: 0 PID: 743 at drivers/clk/clk.c:594 clk_core_disable_lock+0x18/0x24
WARNING: CPU: 0 PID: 743 at drivers/clk/clk.c:476 clk_unprepare+0x24/0x2c

Fixes: 038ac869c9d2 ("spi: stm32: add runtime PM support")

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1625646426-5826-2-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32h7: fix full duplex irq handler handling

In case of Full-Duplex mode, DXP flag is set when RXP and TXP flags are
set. But to avoid 2 different handlings, just add TXP and RXP flag in
the mask instead of DXP, and then keep the initial handling of TXP and
RXP events.
Also rephrase comment about EOTIE which is one of the interrupt enable
bits. It is not triggered by any event.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/1625042723-661-3-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Fix use-after-free on unbind

stm32_spi_remove() accesses the driver's private data after calling
spi_unregister_master() even though that function releases the last
reference on the spi_master and thereby frees the private data.

Fix by switching over to the new devm_spi_alloc_master() helper which
keeps the private data accessible until the driver has unbound.

Fixes: 8d559a64f00b ("spi: stm32: drop devres version of spi_register_master")

Reported-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1616052290-10887-1-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: avoid ifdef CONFIG_PM for pm callbacks

Avoid CONFIG_PM preprocessor check for pm suspend/resume
callbacks and identify the functions with __maybe_unused.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1615545329-5496-1-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: drop devres version of spi_register_master

A call to spi_unregister_master() triggers calling remove()
for all the spi devices binded to the spi master.

Some spi device driver requires to "talk" with the spi device
during the remove(), e.g.:
- a LCD panel like drivers/gpu/drm/panel/panel-lg-lg4573.c
will turn off the backlighting sending a command over spi.
This implies that the spi master must be fully functional when
spi_unregister_master() is called, either if it is called
explicitly in the master's remove() code or implicitly by the
devres framework.

Devres calls devres_release_all() to release all the resources
"after" the remove() of the spi master driver (check code of
__device_release_driver() in drivers/base/dd.c).
If the spi master driver has an empty remove() then there would
be no issue; the devres_release_all() will release everything
in reverse order w.r.t. probe().
But if code in spi master driver remove() disables the spi or
makes it not functional (like in this spi-stm32), then devres
cannot be used safely for unregistering the spi master and the
binded spi devices.

Replace devm_spi_register_master() with spi_register_master()
and add spi_unregister_master() as first action in remove().

Fixes: dcbe0d84dfa5 ("spi: add driver for STM32 SPI controller")

Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1615545286-5395-1-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: make spurious and overrun interrupts visible

We do not expect to receive spurious interrupts so rise a warning
if it happens.

RX overrun is an error condition that signals a corrupted RX
stream both in dma and in irq modes. Report the error and
abort the transfer in either cases.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-9-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32h7: replace private SPI_1HZ_NS with NSEC_PER_SEC

Replace SPI_1HZ_NS private constant with NSEC_PER_SEC, which is easier
to read and understand.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-8-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: defer probe for reset

Defer the probe operation when a reset controller device is expected
but have not yet been probed.

This change replaces use of devm_reset_control_get_exclusive() with
devm_reset_control_get_optional_exclusive() as reset controller is
optional which is now explicitly stated.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-7-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: driver uses reset controller only at init

Remove reset controller device reference from the device private
structure since it is used only at probe time and can be discarded
once used to reset the SPI device.

Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-6-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32h7: ensure message are smaller than max size

Ensure that messages given to transfer_one handler can actually be
handled by it. For that purpose rely on the SPI framework
spi_split_transfers_maxsize function to split messages whenever necessary.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-5-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: use bitfield macros

To avoid defining shift and mask separately and hand-coding the bit
manipulation, use the bitfield macros.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-4-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: do not mandate cs_gpio

CS gpios is not mandatory, the driver should allow working
even when CS are not given.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-3-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: properly handle 0 byte transfer

On 0 byte transfer request, return straight from the
xfer function after finalizing the transfer.

Fixes: dcbe0d84dfa5 ("spi: add driver for STM32 SPI controller")
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-2-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Simplify stm32h7_spi_prepare_fthlv()

Simplify stm32h7_spi_prepare_fthlv() function implementation,
no functional change intended.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alain Volmat <alain.volmat@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Amelie Delaunay <amelie.delaunay@st.com>
Cc: Antonio Borneo <antonio.borneo@st.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Roman Guskov <rguskov@dh-electronics.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-spi@vger.kernel.org
Link: https://lore.kernel.org/r/20210104123114.261596-1-marex@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: update dev_dbg() print format for SPI params

With the introduction of the 'include/uapi/linux/spi/spi.h' header, the
type of the macros are enforced to 'unsigned long int' via the _BITUL()
macro.

This causes some -Wformat warnings in the spi-stm32 driver.
This patch adds a double-negation operator to the bit-masks. Essentially,
the important values for debugging are 0 or 1, while masking them directly
would show 0 or BIT(x) values.
This way, the type of the arguments are automatically re-cast.

Fixes: f7005142dace ("spi: uapi: unify SPI modes into a single spi.h header")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210104143103.56510-1-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: FIFO threshold level - fix align packet size

if cur_bpw <= 8 and xfer_len < 4 then the value of fthlv will be 1 and
SPI registers content may have been lost.

* If SPI data register is accessed as a 16-bit register and DSIZE <= 8bit,
better to select FTHLV = 2, 4, 6 etc

* If SPI data register is accessed as a 32-bit register and DSIZE > 8bit,
better to select FTHLV = 2, 4, 6 etc, while if DSIZE <= 8bit,
better to select FTHLV = 4, 8, 12 etc

Signed-off-by: Roman Guskov <rguskov@dh-electronics.com>
Fixes: dcbe0d84dfa5 ("spi: add driver for STM32 SPI controller")
Reviewed-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20201221123532.27272-1-rguskov@dh-electronics.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix reference leak in stm32_spi_resume

pm_runtime_get_sync will increment pm usage counter even it
failed. Forgetting to pm_runtime_put_noidle will result in
reference leak in stm32_spi_resume, so we should fix it.

Fixes: db96bf976a4fc ("spi: stm32: fixes suspend/resume management")
Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Reviewed-by: Alain Volmat <alain.volmat@st.com>
Link: https://lore.kernel.org/r/20201106015217.140476-1-zhangqilong3@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-stm32: remove redundant irqsave and irqrestore in hardIRQ

Running in hardIRQ, disabling IRQ is redundant.

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Link: https://lore.kernel.org/r/20200926001616.21292-2-song.bao.hua@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix pm_runtime_get_sync() error checking

The pm_runtime_get_sync() can return either 0 or 1 on success but this
code treats 1 as a failure.

Fixes: db96bf976a4f ("spi: stm32: fixes suspend/resume management")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Alain Volmat <alain.volmat@st.com>
Link: https://lore.kernel.org/r/20200909094304.GA420136@mwanda
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Simplify with dev_err_probe()

Common pattern of handling deferred probe can be simplified with
dev_err_probe(). Less code and the error value gets printed.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200901152713.18629-8-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Rate-limit the 'Communication suspended' message

The 'spi_stm32 44004000.spi: Communication suspended' message means that
when using PIO, the kernel did not read the FIFO fast enough and so the
SPI controller paused the transfer. Currently, this is printed on every
single such event, so if the kernel is busy and the controller is pausing
the transfers often, the kernel will be all the more busy scrolling this
message into the log buffer every few milliseconds. That is not helpful.

Instead, rate-limit the message and print it every once in a while. It is
not possible to use the default dev_warn_ratelimited(), because that is
still too verbose, as it prints 10 lines (DEFAULT_RATELIMIT_BURST) every
5 seconds (DEFAULT_RATELIMIT_INTERVAL). The policy here is to print 1 line
every 50 seconds (DEFAULT_RATELIMIT_INTERVAL * 10), because 1 line is more
than enough and the cycles saved on printing are better left to the CPU to
handle the SPI. However, dev_warn_once() is also not useful, as the user
should be aware that this condition is possibly recurring or ongoing. Thus
the custom rate-limit policy.

Finally, turn the message from dev_warn() to dev_dbg(), since the system
does not suffer any sort of malfunction if this message appears, it is
just slowing down. This further reduces the printing into the log buffer
and frees the CPU to do useful work.

Fixes: dcbe0d84dfa5 ("spi: add driver for STM32 SPI controller")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Amelie Delaunay <amelie.delaunay@st.com>
Cc: Antonio Borneo <borneo.antonio@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20200905151913.117775-1-marex@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: always perform registers configuration prior to transfer

SPI registers content may have been lost upon suspend/resume sequence.
So, always compute and apply the necessary configuration in
stm32_spi_transfer_one_setup routine.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
Link: https://lore.kernel.org/r/1597043558-29668-6-git-send-email-alain.volmat@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fixes suspend/resume management

This patch adds pinctrl power management, and reconfigure spi controller
in case of resume.

Fixes: 038ac869c9d2 ("spi: stm32: add runtime PM support")

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Alain Volmat <alain.volmat@st.com>
Link: https://lore.kernel.org/r/1597043558-29668-5-git-send-email-alain.volmat@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix stm32_spi_prepare_mbr in case of odd clk_rate

Fix spi->clk_rate when it is odd to the nearest lowest even value because
minimum SPI divider is 2.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Alain Volmat <alain.volmat@st.com>
Link: https://lore.kernel.org/r/1597043558-29668-4-git-send-email-alain.volmat@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix fifo threshold level in case of short transfer

When transfer is shorter than half of the fifo, set the data packet size
up to transfer size instead of up to half of the fifo.
Check also that threshold is set at least to 1 data frame.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Alain Volmat <alain.volmat@st.com>
Link: https://lore.kernel.org/r/1597043558-29668-3-git-send-email-alain.volmat@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32h7: fix race condition at end of transfer

The caller of stm32_spi_transfer_one(), spi_transfer_one_message(),
is waiting for us to call spi_finalize_current_transfer() and will
eventually schedule a new transfer, if available.
We should guarantee that the spi controller is really available
before calling spi_finalize_current_transfer().

Move the call to spi_finalize_current_transfer() _after_ the call
to stm32_spi_disable().

Signed-off-by: Antonio Borneo <antonio.borneo@st.com>
Signed-off-by: Alain Volmat <alain.volmat@st.com>
Link: https://lore.kernel.org/r/1597043558-29668-2-git-send-email-alain.volmat@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: clear only asserted irq flags on interrupt

Previously the stm32h7 interrupt thread cleared all non-masked interrupts.
If an interrupt was to occur during the handling of another interrupt its
flag would be unset, resulting in a lost interrupt.
This patches fixes the issue by clearing only the currently set interrupt
flags.

Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
Link: https://lore.kernel.org/r/20200804195136.1485392-1-t.schramm@manjaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4

in l3gd20 driver startup, there is a setup failed error return from
stm32 spi driver

"
[ 2.687630] st-gyro-spi spi0.0: supply vdd not found, using dummy
regulator
[ 2.696869] st-gyro-spi spi0.0: supply vddio not found, using dummy
regulator
[ 2.706707] spi_stm32 40015000.spi: SPI transfer setup failed
[ 2.713741] st-gyro-spi spi0.0: SPI transfer failed: -22
[ 2.721096] spi_master spi0: failed to transfer one message from queue
[ 2.729268] iio iio:device0: failed to read Who-Am-I register.
[ 2.737504] st-gyro-spi: probe of spi0.0 failed with error -22
"

after debug into spi-stm32 driver, st-gyro-spi split two steps to read
l3gd20 id

first: send command to l3gd20 with read id command in tx_buf, rx_buf
is null.
second: read id with tx_buf is null, rx_buf not null.

so, for second step, stm32 driver recongise this process as 'SPI_SIMPLE_RX'
from stm32_spi_communication_type(), but there is no related process for this
type in stm32f4_spi_set_mode(), then we get error from
stm32_spi_transfer_one_setup().

we can use two method to fix this bug.
1, use stm32 spi's "In unidirectional receive-only mode (BIDIMODE=0 and
RXONLY=1)". but as our code running in sdram, the read latency is too large
to get so many receive overrun error in interrupts handler.

2, use stm32 spi's "In full-duplex (BIDIMODE=0 and RXONLY=0)", as tx_buf is
null, so add flag 'SPI_MASTER_MUST_TX' to spi master.

Change since V4:
1 remove dummy data sent out by stm32 spi driver
2 add flag 'SPI_MASTER_MUST_TX' to spi master

Signed-off-by: dillon min <dillon.minfei@gmail.com>
Link: https://lore.kernel.org/r/1590378348-8115-8-git-send-email-dillon.minfei@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Fix comments compilation warnings

Fix all functions and structure descriptions to have the driver
warning free when built with W=1.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
Reviewed-by: Amelie Delaunay <amelie.delaunay@st.com>
Link: https://lore.kernel.org/r/1584711857-9162-1-git-send-email-alain.volmat@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Use dma_request_chan() instead dma_request_slave_channel()

dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.

By using dma_request_chan() directly the driver can support deferred
probing against DMA.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20191212135550.4634-10-peter.ujfalusi@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Switch to use GPIO descriptors for CS

This switches the STM32 SPI driver over to using GPIO
descriptors for chip select. Instead of the callbacks for
picking the GPIO lines using the legacy API we just let
the core handle it all using descriptors.

Cc: Fabien Dessenne <fabien.dessenne@st.com>
Cc: Amelie Delaunay <amelie.delaunay@st.com>
Cc: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20191205083401.27077-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: return the get_irq error

During probe, return the "get_irq" error value instead of -ENOENT. This
allows the driver to be defer probed if needed.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Acked-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: add support for STM32F4

Add routines, registers & bitfield definition. Also baud rate divisor
definitions for STM32F4 SPI. This version supports full-duplex,
simplex TX and half-duplex TX communication with 8 or 16-bit per word.
DMA capability is optionally supported for transfer longer than 16 bytes.
For transfer less than 16 bytes frames can be send in discontinuous mode.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: introduce compatible data cfg

Prepare support for STM32F4 spi variant by introducing compatible
configuration data.
Move STM32H7 specific stuff to compatible data structure:
- registers & bit fields
- routines to control driver
- baud rate divisor definitions
- fifo availability
- split IRQ functions to parts to be called when the IRQ occurs
and for threaded interrupt what helps to provide less discontinuous
mode for drivers without FIFO.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: add start dma transfer function

Add transfer_one_dma_start function to be more generic for other
stm32 SPI family drivers.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: split transfer one setup function

Split stm32_spi_transfer_one_setup function into smaller chunks
to be more generic for other stm32 SPI family drivers.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: rename interrupt function

Interrupt function is used as a thread so rename it to express
meaning directly by more clear function name.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: rename STM32 SPI registers to STM32H7

Rename STM32 SPI registers to be related to STM32H7 SPI driver
and not STM32 generally.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: remove SPI LOOP mode

This driver does not support SPI LOOP mode by configuration
in registers.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: use explicit CPOL and CPHA mode bits

Driver supports SPI mode 0 to 3 not only the mode 3.
Use SPI_CPOL and SPI_CPHA indicates that these bits
can be changed to obtain modes 0 - 3.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix DMA configuration with only one channel

When SPI driver is configured to work only with TX or RX DMA channel
then dmaengine functions can dereferene NULL pointer.

Running full-duplex mode when when only RX or TX DMA channel is
available can cause overrun condition or incorrect writing to transmit
buffer so disable this types of DMA configuration and go back to
interrupt mode.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: use NULL pointer instead of plain integer

Patch fixes sparse warning: Using plain integer as NULL pointer. Replaces
second argument of function devm_clk_get from 0 to NULL.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.

Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Fix error handling in stm32_spi_probe()

clk_get_rate() is below clk_prepare_enable(), so
its error should lead to goto err_clk_disable, not to err_master_put.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Reviewed-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: Fix logical error in stm32_spi_prepare_mbr()

stm32_spi_prepare_mbr() is returning an error value when div is less
than SPI_MBR_DIV_MIN *and* greater than SPI_MBR_DIV_MAX, which always
evaluates to false. This should change to use *or*.

Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: explicitly request exclusive reset control

Commit a53e35db70d1 ("reset: Ensure drivers are explicit when requesting
reset lines") started to transition the reset control request API calls
to explicitly state whether the driver needs exclusive or shared reset
control behavior. Convert all drivers requesting exclusive resets to the
explicit API call so the temporary transition helpers can be removed.

No functional changes.

Cc: Mark Brown <broonie@kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: linux-spi@vger.kernel.org
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix potential dereference null return value

This patch fixes the usage of rx_dma_desc and tx_dma_desc pointers
returned by dmaengine_prep_slave_sg, which can be null.

Detected by CoverityScan, CID#1446587 ("Dereference null return value")

Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: enhance DMA error management

This patch reworks DMA error management. In case the DMA callback is
called while EOT (End Of Transfer) flag is not set, that means that DMA
encountered an error. This error will result in an auto-suspend of SPI
flow, which could also result in an overrun. So, in DMA mode, SUSP and
OVR flags are a condition to stop the current transfer.

Moreover, stm32_spi_can_dma doesn't care about the state of dma channels.
During driver probe, master->can_dma is initialised if dma channel request
is successful. That's why we must use master->can_dma to know if dma
use is possible (dma channel are successfully requested and the transfer
size is greater than fifo size).

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: add runtime PM support

This patch reworks suspend and resume callbacks and add runtime_suspend
and runtime_resume callbacks.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: use normal conditional statements instead of ternary operator

This patch replace ternary operator use by normal condition statements
to ease code reading.
It also removes redundant !!.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: replace st, spi-midi with st, spi-midi-ns to fit bindings

This patch fixes the optional dt property used to set master inter-data
idleness.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix compatible to fit with new bindings

This patch updates of_device_id compatible string to fit with new
bindings.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32: fix error check on mbr being -ve

The error check of mbr < 0 is always false because mbr is a u32. Make
mbt an int so that a -ve error return from stm32_spi_prepare_mbr can be
detected.

Detected by CoverityScan, CID#1446586 ("Unsigned compared against 0")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add driver for STM32 SPI controller

The STM32 Serial Peripheral Interface (SPI) can be used to communicate
with external devices while using the specific synchronous protocol. It
supports a half-duplex, full-duplex and simplex synchronous, serial
communication with external devices with 4-bit to 16/32-bit per word. It
has two 8x/16x 8-bit embedded Rx and TxFIFOs with DMA capability. It can
operate in master or slave mode.

Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>