ARM-based 63xx DSL platforms have the spi-bcm63xx-hsspi controller
present, allow using this driver there as well.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Add support to use McSPI controller as SPI slave. In slave mode, DMA TX
completion does not mean entire data has been shifted out as data might
still be stuck in FIFO waiting for master to clock the bus. Therefore,
add an IRQ handler for slave mode to know when entire data in FIFO has
been shifted out.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
McSPI has 32 byte FIFO in Transmit-Receive mode. Current code tries to
configuration FIFO watermark level for DMA trigger to be GCD of transfer
length and max FIFO size which would mean trigger level may be set to 32
for transmit-receive mode if length is aligned. This does not work in
case of SPI slave mode where FIFO always needs to have data ready
whenever master starts the clock. With DMA trigger size of 32 there will
be a small window during slave TX where DMA is still putting data into
FIFO but master would have started clock for next byte, resulting in
shifting out of stale data. Similarly, on Slave RX side there may be RX
FIFO overflow
Fix this by setting FIFO watermark for DMA trigger to word
length. This means DMA is triggered as soon as FIFO has space for word
length bytes and DMA would make sure FIFO is almost always full
therefore improving FIFO occupancy in both master and slave mode.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Use standard readl_poll_timeout() macro for polling on status bits.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
The qspi controller is a specialized communication interface
targeting single, dual or quad SPI Flash memories (NOR/NAND).
It can operate in any of the following modes:
-indirect mode: all the operations are performed using the quadspi
registers
-read memory-mapped mode: the external Flash memory is mapped to the
microcontroller address space and is seen by the system as if it was
an internal memory
tested on:
-NOR: mx66l51235l
-NAND: MT29F2G01ABAGD
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch adds the documentation of device tree bindings
for the STM32 QSPI controller. It is a specialized communication
interface targeting single, dual or quad SPI Flash memories (NOR/NAND).
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Document the R-Car V3{M|H} (R8A779{7|8}0) SoCs in the Renesas MSIOF
bindings.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Mark Brown <broonie@kernel.org>
The DMA API does its own zone decisions based on the coherent_dma_mask.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Use PIO mode instead if size is smaller than fifo size, since
dma may be less efficient.
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Correct wml as the last rx sg length instead of the whole transfer
length. Otherwise, mtd_stresstest will be failed as below:
insmod mtd_stresstest.ko dev=0
=================================================
mtd_stresstest: MTD device: 0
mtd_stresstest: not NAND flash, assume page size is 512 bytes.
mtd_stresstest: MTD device size 4194304, eraseblock size 65536, page size 512, count of eraseblocks 64, pa0
mtd_stresstest: doing operations
mtd_stresstest: 0 operations done
mtd_test: mtd_read from 1ff532, size 880
mtd_test: mtd_read from 20c267, size 64998
spi_master spi0: I/O Error in DMA RX
m25p80 spi0.0: SPI transfer failed: -110
spi_master spi0: failed to transfer one message from queue
mtd_test: error: read failed at 0x20c267
mtd_stresstest: error -110 occurred
=================================================
insmod: ERROR: could not insert module mtd_stresstest.ko: Connection timed out
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Current dynamic burst length is based on the whole transfer length,
that's ok if there is only one sg, but is not right in case multi sgs
in one transfer,because the tail data should be based on the last sg
length instead of the whole transfer length. Move wml setting for DMA
to the later place, thus, the next patch could get the right last sg
length for wml setting. This patch is a preparation one, no any
function change involved.
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This spares drivers from #ifdef-ing on CONFIG_PCI if the driver can be
optionally built on machines without PCI bus.
Consistent with acpi_driver_match_device() and similar.
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Mark Brown <broonie@kernel.org>
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>
This is the SPI controller found on Marvel MMP2 and perhaps more
platforms.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Mark Brown <broonie@kernel.org>
The MMP2 platform, that uses device tree, has this controller. Let's add
devicetree alongside platform & PCI.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Mark Brown <broonie@kernel.org>
This driver supports GENI based SPI Controller in the Qualcomm SOCs. The
Qualcomm Generic Interface (GENI) is a programmable module supporting a
wide range of serial interfaces including SPI. This driver supports SPI
operations using FIFO mode of transfer.
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
Signed-off-by: Dilip Kota <dkota@codeaurora.org>
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Move GENI SE SPI controller device-tree bindings
from devicetree/bindings/soc/qcom/qcom,geni-se.txt
to devicetree/bindings/spi/qcom,spi-geni-qcom.txt.
Signed-off-by: Dilip Kota <dkota@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
SPI controller driver should maintain the maximum frequency
of the controller instead of relying on device tree bindings.
Because maximum frequency is specific property of SPI
controller.
Signed-off-by: Dilip Kota <dkota@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Let the dma/non-dma code paths handle the spi enable
flag themselves. This removes some logic to determine
if the flag should be turned on before or after dma
and also don't leave the spi enabled if the dma path
fails.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
The dma direction for the tx and rx dma channels never
change, so just use the constants directly rather
than storing them in device data.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
The driver data has a u32 field use_dma which is
only ever used as a boolean, so change its type
to reflect that.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
We no longer need the dma_caps since the dma driver
already clamps the burst length to the hardware limit,
so don't request and store dma_caps in device data.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signal tx dma when spi fifo is less than half full,
and limit tx bursts to half the fifo length.
Clamp rx burst length to 1 to avoid alignment issues.
Signed-off-by: Huibin Hong <huibin.hong@rock-chips.com>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
New driver for Qualcomm QuadSPI(QSPI) controller that is used to
communicate with slaves such as flash memory devices. The QSPI controller
can operate in 2 or 4 wire mode but only supports SPI Mode 0. The
controller can also operate in Single or Dual data rate modes.
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
Signed-off-by: Ryan Case <ryandcase@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Bindings for Qualcomm Quad SPI used on SoCs such as sdm845.
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
Signed-off-by: Ryan Case <ryandcase@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Add support for a new devicetree compatible string called
'amazon,alpine-apb-ssi', which is necessary for the Amazon Alpine spi
controller. 'amazon,alpine-dw-apb-ssi' is used in the dw spi driver if
specified in the devicetree. Otherwise, fall back to driver default
behavior, i.e. original dw IP hw driver behavior.
Signed-off-by: Talel Shenhar <talel@amazon.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>
This compatible adds the ability for dw spi controller driver to work with
the dw spi controller found on Alpine chips.
The dw spi controller has an auto-deselect of Chip-Select, in case there is
no data inside the Tx FIFO. While working on platforms with Alpine chips,
auto-deselect mode causes an issue for some spi devices that can't handle
the Chip-Select deselect in the middle of a transaction. It is a normal
behavior for a Tx FIFO to be empty in the middle of a transaction, due to
busy cpu. In the Alpine chip family an option to change the default
behavior was added to the original dw spi controller to prevent this issue
of de-asserting Chip-Select once TX FIFO is empty. The change was to allow
SW manual control of the Chip-Select. With this change, as long as the
Slave Enable Register is asserted, the Chip-Select will be asserted. As a
result, it is necessary to deselect the Slave Select Register once the
transaction is done. This feature is enabled via a new device compatible
string called 'amazon,alpine-dw-apb-ssi'. Once the driver identifies the
new compatible string, it enables the hw fixup logic, by writing to a
dedicated register found in the IP reserved area and will start manual
deselecting the Slave Select Register when the transfer ends.
Signed-off-by: Talel Shenhar <talel@amazon.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>
spidev will make a big fuss if a device tree node binds a device by
using "spidev" as the node's compatible property.
However, the logic for this isn't looking for "spidev" in the
compatible, but rather checking that the device is NOT compatible with
spidev's list of devices.
This causes a false positive if a device not named "rohm,dh2228fv", etc.
binds to spidev, even if a means other than putting "spidev" in the
device tree was used. E.g., the sysfs driver_override attribute.
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>
This attribute works the same was as the identically named attribute
for PCI, AMBA, and platform devices. For reference, see:
commit 3cf3857134 ("ARM: 8256/1: driver coamba: add device binding
path 'driver_override'")
commit 3d713e0e38 ("driver core: platform: add device binding path
'driver_override'")
commit 782a985d7a ("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>
Certain devices don't work well when a transmit FIFO underrun or
receive FIFO overrun occurs. Example is the SAF400x radio chip when
running at high speed which leads to garbage being sent to/received from
the chip. In which case, it should stall waiting for further data to be
available before proceeding. This patch unset the NOSTALL bit in CFGR1
by default to prevent this issue.
Signed-off-by: Hieu Tran Dang <dangtranhieu2012@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Clang warns when one enumerated type is implicitly converted to another.
drivers/spi/spi-ep93xx.c:342:62: warning: implicit conversion from
enumeration type 'enum dma_transfer_direction' to different enumeration
type 'enum dma_data_direction' [-Wenum-conversion]
nents = dma_map_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
./include/linux/dma-mapping.h:428:58: note: expanded from macro
'dma_map_sg'
#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)
~~~~~~~~~~~~~~~~ ^
drivers/spi/spi-ep93xx.c:348:57: warning: implicit conversion from
enumeration type 'enum dma_transfer_direction' to different enumeration
type 'enum dma_data_direction' [-Wenum-conversion]
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
./include/linux/dma-mapping.h:429:62: note: expanded from macro
'dma_unmap_sg'
#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, 0)
~~~~~~~~~~~~~~~~~~ ^
drivers/spi/spi-ep93xx.c:377:56: warning: implicit conversion from
enumeration type 'enum dma_transfer_direction' to different enumeration
type 'enum dma_data_direction' [-Wenum-conversion]
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
./include/linux/dma-mapping.h:429:62: note: expanded from macro
'dma_unmap_sg'
#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, 0)
~~~~~~~~~~~~~~~~~~ ^
3 warnings generated.
dma_{,un}map_sg expect an enum of type dma_data_direction but this
driver uses dma_transfer_direction for everything. Convert the driver to
use dma_data_direction for these two functions.
There are two places that strictly require an enum of type
dma_transfer_direction: the direction member in struct dma_slave_config
and the direction parameter in dmaengine_prep_slave_sg. To avoid using
an explicit cast, add a simple function, ep93xx_dma_data_to_trans_dir,
to safely map between the two types because they are not 1 to 1 in
meaning.
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
With this commit the DSPI driver on the BK4 board can be used for SPI
transmission managed from user space (via /dev/spidev0.0).
Example usage/testing:
insmod ./spi-fsl-dspi.ko
./spidev_test -D /dev/spidev0.0 -s 3000000 -v -H -b 8 -p "\xCC\x11\x22\x74"
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Rewrite switch code block to directly do the expected number
of shifts in each case and have break statements.
Addresses-Coverity-ID: 1056539 ("Missing break in switch")
Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Apparently, this code does not actually fall through to the next case
because the machine restarts before it has a chance. However, for the
sake of maintenance and readability, we better add the missing break
statement.
Addresses-Coverity-ID: 1437892 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Document RZ/G1N (R8A7744) SoC bindings.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Mark Brown <broonie@kernel.org>
Document RZ/G1N (r8a7744) SoC specific bindings.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch adds a DT binding documentation for the MT2712 soc.
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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>
On r8a7791/koelsch:
m25p80 spi0.0: error -22 reading 9f
m25p80: probe of spi0.0 failed with error -22
Apparently the logic in spi_mem_check_op() is wrong, rejecting the
spi-mem operation if any buswidth is valid, instead of invalid.
Fixes: 380583227c ("spi: spi-mem: Add extra sanity checks on the op param")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
The __exit section is left out for built-in drivers, so a
'remove' callback must not be marked as such to avoid breaking when
we unbind a device at runtime. This was pointed out by kbuild:
`sprd_spi_remove' referenced in section `.data' of drivers/spi/spi-sprd.o: defined in discarded section `.exit.text' of drivers/spi/spi-sprd.o
Fixes: e7d973a31c ("spi: sprd: Add SPI driver for Spreadtrum SC9860")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
The geni_se_clk_freq_match() has some strange semantics. Specifically
it is defined with two modes:
1. It can find a clock that's an exact multiple of the requested rate
2. It can find a non-exact match but it can't handle multiples then
...but callers should always be able to handle a clock that is a
multiple of the requested clock so mode #2 doesn't really make sense.
Let's change the semantics so that the non-exact match can also accept
multiples and then change the code to handle that.
The only caller of this code is the unlanded SPI driver [1] which
currently passes "exact = True", thus it should be safe to change the
semantics in this way. ...and, in fact, the SPI driver should likely
be modified to pass "exact = False" (with the new semantics) since
that will allow it to work with SPI devices that request a clock rate
that doesn't exactly match a rate we can make.
[1] https://lkml.kernel.org/r/1535107336-2214-1-git-send-email-dkota@codeaurora.org
Fixes: eddac5af06 ("soc: qcom: Add GENI based QUP Wrapper driver")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
The function clk_round_rate() is defined to return a "long", not an
"unsigned long". That's because it might return a negative error
code. Change the call in geni_se_clk_tbl_get() to check for errors.
While we're at it, get rid of a useless init of "freq".
NOTE: overall the idea that we should iterate over clk_round_rate() to
try to reconstruct a table already present in the clock driver is
questionable. Specifically:
- This method relies on "clk_round_rate()" rounding up.
- This method only works if the table is sorted and has no duplicates.
...this patch doesn't try to fix those problems, it just makes the
error handling more correct.
Fixes: eddac5af06 ("soc: qcom: Add GENI based QUP Wrapper driver")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
This macro doesn't work, because it hides a local variable inside of the
macro to hold the version and that variable name is called 'ver' and
'version' sometimes.
Let's change this to be more explicit. Introduce three macros for the
major, minor, and step of the version, and require callers to pass the
version in to get the part of the version out. This way we don't hide
local variables inside macros and things are less evil overall.
Cc: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Cc: Sagar Dharia <sdharia@codeaurora.org>
Cc: Girish Mahadevan <girishm@codeaurora.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Clang warns when one enumerated type is converted implicitly to another:
drivers/spi/spi-pic32.c:323:8: warning: implicit conversion from
enumeration type 'enum dma_data_direction' to different enumeration type
'enum dma_transfer_direction' [-Wenum-conversion]
DMA_FROM_DEVICE,
^~~~~~~~~~~~~~~
drivers/spi/spi-pic32.c:333:8: warning: implicit conversion from
enumeration type 'enum dma_data_direction' to different enumeration type
'enum dma_transfer_direction' [-Wenum-conversion]
DMA_TO_DEVICE,
^~~~~~~~~~~~~
2 warnings generated.
Use the proper enums from dma_transfer_direction (DMA_FROM_DEVICE =
DMA_DEV_TO_MEM = 2, DMA_TO_DEVICE = DMA_MEM_TO_DEV = 1) to satify Clang.
Link: https://github.com/ClangBuiltLinux/linux/issues/159
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Some combinations are simply not valid and should be rejected before
the op is passed to the SPI controller driver.
Add an spi_mem_check_op() helper and use it in spi_mem_exec_op() and
spi_mem_supports_op() to make sure the spi-mem operation is valid.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>