Add explanation about using the the rx buffer as the
dummy tx buffer.
Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Using vmalloc'ed buffers will fail since daVinci has
VIVT cache and only the kernel lowmem virtual address
is invalidated/flushed when performing DMA.
The virtual address returned from vmalloc() is not
invalidated/flushed and may contain stale data when
returning from spi_sync().
Fixes errors when running UBIFS over SPI NOR.
Revert this when all upper layer users of vmalloc'ed
buffers sent to SPI handles cache flushing/invalidating.
Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Higher bitrate and lower CPU load if using PIO in this case.
Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
When doing rx-only transfer, the transfer will fail
if the number of SG entries exceeds 20.
This happens because the eDMA DMA engine is limited
to 20 SG entries in one transaction, and when the
DMA transcation is resumed (which takes > 150us),
rx errors occurs because the slave is still transmitting.
Fix this by using the rx buffer as the dummy tx buffer,
so that resuming the rx transcation happens at the same
time as resuming the tx transcation.
Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
When booting with DT the SPI driver is always using
the SPI_IO_TYPE_INTR mode to transfer data even if DMA channels are
defined in the DT.
This commit changes the behaviour to select the SPI_IO_TYPE_DMA mode
if DMA channels are defined in the DT and will keep SPI_IO_TYPE_INTR
if the channels are not defined in it.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Uppers layers like MTD can pass vmalloc'd buffers to the SPI driver,
and the current implementation will fail to map these kind of buffers.
The SPI framework is able to detect the best way to handle and map
buffers.
This commit updates the davinci SPI driver in order to use the SPI
framework to handle the DMA mapping of buffers coming from an upper
layer.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
The correct error checking for dma_map_single() is to use
dma_mapping_error().
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
With the new dma_request_chan() the client driver does not need to look for
the DMA resource and it does not need to pass filter_fn anymore.
By switching to the new API the driver can now support deferred probing
against DMA.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
davinci_spi_bufs() uses wait_for_completion_interruptible()
without bothering to handle -ERESTARTSYS. Due to this,
sometime, it returns prematurely when a signal is received.
Since the return value is never checked, userspace eventually
receives a spurious -EIO.
To fix this, use un-interruptible wait_for_completion_timeout().
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Use spi->cs_gpio directly to remove the following build warning:
drivers/spi/spi-davinci.c:219:6: warning: 'gpio' may be used uninitialized in this function
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
The function can return negative value.
The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/assign_signed_to_unsigned.cocci [1].
[1]: http://permalink.gmane.org/gmane.linux.kernel/2046107
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently the pre-scaler limit is incorrect. The value differs slightly
for various devices so a single value can't be used. Using the compatible
field select the correct pre-scaler limit.
Add new compatible field value for Keystone devices to support their
unique pre-scaler limit value.
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Within davinci_spi_get_prescale() the prescale has two meanings. First one
being the calculated prescale value and then at the end translates it to the
prescale value that will be written to the SPI register.
At first glance this can be confusing especially when comparing the minimum
prescale value against what is seen in the TRM.
To simplify things make it clear that the calculated prescale value will always
be based on the value that will be written into the SPI register.
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
SPI hardware spec for Keystone specify a lower value of 0 for pre-scale
divider which determine what max value of spi clock (spi-max-frequency)
the device can support. This translates to a clock divider of 2. So fix
the lower limit value used for the boundary check in
davinci_spi_get_prescale() function to 1 so that a maximum of spi device
clock rate / 2 is possible to be set for spi-max-frequency.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch adds ability to configure delay between transmission of
words over SPI bus if it's required by SPI slave devices.
New optional SPI slave property:
- ti,spi-word-delay : delay between transmission of words
(SPIFMTn.WDELAY, SPIDAT1.WDEL)
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Remove empty function davinci_spi_cleanup().
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Now CS GPIOs are requested from struct spi_master.setup() callback
and that causes failures when Client SPI device is getting accessed
through SPIDEV driver. The failure happens, because .setup() callback
may be called many times from IOCTL handler and when it's called
second time gpio_request() will fail and return -EBUSY.
Hence, fix it by moving CS GPIOs requesting code in .probe().
Reported-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Fix the following checkpatch warnings.
WARNING: Missing a blank line after declarations
WARNING: quoted string split across lines
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
The driver should not touch CS lines if SPI_NO_CS flag is set.
This patch fixes it as this functionality was broken accidentally
by
commit a88e34ea21 ("spi: davinci: add support to configure gpio cs through dt").
Fixes: a88e34ea21 ("spi: davinci: add support to configure gpio cs through dt")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Rework Davinci SPI driver to store GPIO CS number in cs_gpio field
of SPI device structure (spi_device) for both DT and non-DT cases.
This will make Davinci SPI driver code simpler and allows to reuse
more SPI core functionality.
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Currently driver supports only configuration of GPIO CS through
platform data. This patch enhances the driver to configure GPIO
CS through DT. Also update the DT binding documentation to
reflect the availability of cs-gpios.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Currently, the driver defines SPI_MAX_CHIPSELECT as 2 and
use per device array bytes_per_word based on this. This breaks
if num_chipselect per device is greater than 2. This patch
fix this and allocate memory for this array based on
num_chipselect.
It's preparation patch to enable GPIO CS feature for
Davinci SPI.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
It's pointless to use of_match_ptr within CONFIG_OF guard.
Use of_match_ptr around davinci_spi_of_match when setting .of_match_table.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
spi_master_get_devdata() never returns NULL when spi_alloc_master() success,
so remove NULL test for dspi.
We have ensured master is not NULL before assigning it to dspi->bitbang.master.
So also remove NULL test for dspi->bitbang.master.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
The implementation in spi_setup() already set spi->bits_per_word = 8 when
spi->bits_per_word is 0 before calling spi->master->setup.
So we don't need to do it again in setup() callback.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Barry Song <Baohua.Song@csr.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mark Brown <broonie@linaro.org>
With CONFIG_ARM_LPAE=y spi driver throws below warning
drivers/spi/spi-davinci.c: In function ‘davinci_spi_probe’:
drivers/spi/spi-davinci.c:965:3: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘resource_size_t’ [-Wformat]
drivers/spi/spi-davinci.c:965:3: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘resource_size_t’ [-Wformat]
Lets use '%pa' to properly print 'resource_size_t' type variables.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.
[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many drivers that use bitbang library have a leak on probe error paths.
This is because once a spi_master_get() call succeeds, we need an additional
spi_master_put() call to free the memory.
Fix this issue by moving the code taking a reference to master to
spi_bitbang_start(), so spi_bitbang_start() will take a reference to master on
success. With this change, the caller is responsible for calling
spi_bitbang_stop() to decrement the reference and spi_master_put() as
counterpart of spi_alloc_master() to prevent a memory leak.
So now we have below patten for drivers using bitbang library:
probe:
spi_alloc_master -> Init reference count to 1
spi_bitbang_start -> Increment reference count
remove:
spi_bitbang_stop -> Decrement reference count
spi_master_put -> Decrement reference count (reference count reaches 0)
Fixup all users accordingly.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Suggested-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
'prescale' contains the return value of davinci_spi_get_prescale()
which is a signed integer. Convert 'prescale' to integer to silence
the following warning:
drivers/spi/spi-davinci.c:318 davinci_spi_setup_transfer() warn:
unsigned 'prescale' is never less than zero.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Commit 048177ce3b (spi: spi-davinci:
convert to DMA engine API) introduced a regression: dma_map_single()
is called with direction DMA_FROM_DEVICE for rx and for tx.
Signed-off-by: Christian Eggers <ceggers@gmx.de>
Acked-by: Matt Porter <mporter@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org # v3.7.x+
Fill in the recently added spi_master.bits_per_word_mask field in as
many drivers as possible. Make related cleanups, such as removing any
redundant error-checking, or empty setup callbacks.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Use the wrapper functions for getting and setting the driver data using
platform_device instead of using dev_{get,set}_drvdata() with &pdev->dev,
so we can directly pass a struct platform_device.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Follow DT naming convention for compatible property of the blob.
Use first chip name that introduced the specific version of the
device.
Signed-off-by: Manjunathappa, Prakash <prakash.pm@ti.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
With RT pre-empt patch applied to Linux kernel, the irq handler will be
force converted to an irq thread. spi driver can get back to back messages
from the slave device. In such cases, IRQ thread doesn't get a chance to
run to read the slave data. Hence the irq handler must be run in hard irq
context to read/write data from slave device. Otherwise, the kernel goes
into a deadlock. This patch fixes this issue when PREEMPT_RT_FULL is
enabled in the kernel. A dummy thread function is provided to satisfy the
request_threaded_irq() API. Passing a NULL for function also causes the
irq handler to be executed in the thread context.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This adds OF support to DaVinci SPI controller to configure platform
data through device bindings. Also replaces clk_enable() with
of clk_prepare_enable() as well as clk_disable() with
clk_disable_unprepare().
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
