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commit 794aaf01444d4e765e2b067cba01cc69c1c68ed9 upstream.
We can't rely on the contents of the devres list during
spi_unregister_controller(), as the list is already torn down at the
time we perform devres_find() for devm_spi_release_controller. This
causes devices registered with devm_spi_alloc_{master,slave}() to be
mistakenly identified as legacy, non-devm managed devices and have their
reference counters decremented below 0.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 660 at lib/refcount.c:28 refcount_warn_saturate+0x108/0x174
[<b0396f04>] (refcount_warn_saturate) from [<b03c56a4>] (kobject_put+0x90/0x98)
[<b03c5614>] (kobject_put) from [<b0447b4c>] (put_device+0x20/0x24)
r4:b6700140
[<b0447b2c>] (put_device) from [<b07515e8>] (devm_spi_release_controller+0x3c/0x40)
[<b07515ac>] (devm_spi_release_controller) from [<b045343c>] (release_nodes+0x84/0xc4)
r5:b6700180 r4:b6700100
[<b04533b8>] (release_nodes) from [<b0454160>] (devres_release_all+0x5c/0x60)
r8:b1638c54 r7:b117ad94 r6:b1638c10 r5:b117ad94 r4:b163dc10
[<b0454104>] (devres_release_all) from [<b044e41c>] (__device_release_driver+0x144/0x1ec)
r5:b117ad94 r4:b163dc10
[<b044e2d8>] (__device_release_driver) from [<b044f70c>] (device_driver_detach+0x84/0xa0)
r9:00000000 r8:00000000 r7:b117ad94 r6:b163dc54 r5:b1638c10 r4:b163dc10
[<b044f688>] (device_driver_detach) from [<b044d274>] (unbind_store+0xe4/0xf8)
Instead, determine the devm allocation state as a flag on the
controller which is guaranteed to be stable during cleanup.
Fixes: 5e844cc37a5c ("spi: Introduce device-managed SPI controller allocation")
Signed-off-by: William A. Kennington III <wak@google.com>
Link: https://lore.kernel.org/r/20210407095527.2771582-1-wak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
[lukas: backport to v4.4.270]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5e844cc37a5cbaa460e68f9a989d321d63088a89 ]
SPI driver probing currently comprises two steps, whereas removal
comprises only one step:
spi_alloc_master()
spi_register_master()
spi_unregister_master()
That's because spi_unregister_master() calls device_unregister()
instead of device_del(), thereby releasing the reference on the
spi_master which was obtained by spi_alloc_master().
An SPI driver's private data is contained in the same memory allocation
as the spi_master struct. Thus, once spi_unregister_master() has been
called, the private data is inaccessible. But some drivers need to
access it after spi_unregister_master() to perform further teardown
steps.
Introduce devm_spi_alloc_master(), which releases a reference on the
spi_master struct only after the driver has unbound, thereby keeping the
memory allocation accessible. Change spi_unregister_master() to not
release a reference if the spi_master was allocated by the new devm
function.
The present commit is small enough to be backportable to stable.
It allows fixing drivers which use the private data in their ->remove()
hook after it's been freed. It also allows fixing drivers which neglect
to release a reference on the spi_master in the probe error path.
Long-term, most SPI drivers shall be moved over to the devm function
introduced herein. The few that can't shall be changed in a treewide
commit to explicitly release the last reference on the master.
That commit shall amend spi_unregister_master() to no longer release
a reference, thereby completing the migration.
As a result, the behaviour will be less surprising and more consistent
with subsystems such as IIO, which also includes the private data in the
allocation of the generic iio_dev struct, but calls device_del() in
iio_device_unregister().
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/272bae2ef08abd21388c98e23729886663d19192.1605121038.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The QUP core can be programmed to operate as an SPI slave. This
change modifies the existing SPI master driver and adds the slave
functionality.
Change-Id: I73189339956e0fd52449391737fb1e616a6e0bb2
Signed-off-by: Dilip Kota <dkota@codeaurora.org>
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Add support for registering SPI slave controllers using the existing SPI
master framework:
- SPI slave controllers must use spi_alloc_slave() instead of
spi_alloc_master(), and should provide an additional callback
"slave_abort" to abort an ongoing SPI transfer request,
- SPI slave controllers are added to a new "spi_slave" device class,
- SPI slave handlers can be bound to the SPI slave device represented
by an SPI slave controller using a DT child node named "slave",
- Alternatively, (un)binding an SPI slave handler to the SPI slave
device represented by an SPI slave controller can be done by
(un)registering the slave device through a sysfs virtual file named
"slave".
From the point of view of an SPI slave protocol handler, an SPI slave
controller looks almost like an ordinary SPI master controller. The only
exception is that a transfer request will block on the remote SPI
master, and may be cancelled using spi_slave_abort().
Change-Id: I251c5b7247ee7088285e42dd3b3cdce9c56cb9f7
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
Git-commit: 6c364062bfed3c34490e85bea52ff6e2d4f0f281
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
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This change adds a snapshot of SPI QSD driver from the 3.18 branch.
kernel-3.18 baseline: e70ad0cd5efdd9dc91a77dcdac31d6132e1315c1
Change-Id: I6e2a4be429a2681603a12e5ecb6853582cd3ffbe
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
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Add spi_register_driver helper macro that adds THIS_MODULE to
spi_driver for the registering driver. We rename and modify
the existing spi_register_driver to enable this.
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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When building docs with make htmldocs, warnings about not having
a description for the return value are reported, i.e:
warning: No description found for return value of 'spi_write'
Fix these by following the kernel-doc conventions explained in
Documentation/kernel-doc-nano-HOWTO.txt.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Use for struct pxa2xx_spi_master clock_enable field was removed years ago
from the pxa2xx-spi driver by the commit 2f1a74e5a2de ("[ARM] pxa: make
pxa2xx_spi driver use ssp_request()/ssp_free()").
Therefore remove it from structure definition, documentation and from
couple affected board files.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
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report transfer sizes as a histogram via the following files:
/sys/class/spi_master/spi*/statistics/transfer_bytes_histo_*
/sys/class/spi_master/spi*/spi*.*/statistics/transfer_bytes_histo_*
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
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chipselect (in the case of spi-gpio: spi_gpio_chipselect, which
calls gpiod_set_raw_value_cansleep) can sleep, so we should not
hold a spinlock while calling it from spi_bitbang_setup.
This issue was introduced by this commit, which converted spi-gpio
to cansleep variants:
d9dda5a191 "spi: spi-gpio: Use 'cansleep' variants to access GPIO"
Replacing the lock variable by a mutex fixes the issue: This is
safe as all instances where the lock is used are called from
contexts that can sleep.
Finally, update spi-ppc4xx and and spi-s3c24xx to use mutex
functions, as they directly hold the lock for similar purpose.
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Fix the following 'make htmldocs' warnings:
.//include/linux/spi/spi.h:71: warning: No description found for parameter 'lock'
.//include/linux/spi/spi.h:71: warning: Excess struct/union/enum/typedef member 'clock' description in 'spi_statistics'
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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per spi-master statistics accessible as:
/sys/class/spi_master/spi*/statistics/*
per spi-device statistics accessible via:
/sys/class/spi_master/spi*/spi*.*/statistics/*
The following statistics are exposed as separate "files" inside
these directories:
* messages number of spi_messages
* transfers number of spi_transfers
* bytes number of bytes transferred
* bytes_rx number of bytes transmitted
* bytes_tx number of bytes received
* errors number of errors encounterd
* timedout number of messages that have timed out
* spi_async number of spi_messages submitted using spi_async
* spi_sync number of spi_messages submitted using spi_sync
* spi_sync_immediate number of spi_messages submitted using spi_sync,
that are handled immediately without a context switch
to the spi_pump worker-thread
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
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This patch changes tha way of handling of cc2591-cc2520 combination
by moving amplified variable from platform data to private data.
This will be useful in other sections like tx power support.
Signed-off-by: Varka Bhadram <varkab@cdac.in>
Cc: Brad Campbell <bradjc5@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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If a driver doesn't implement the master->handle_err() callback and an
SPI transfer fails, the kernel will crash with a NULL pointer
dereference:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c0003000
[00000000] *pgd=80000040004003, *pmd=00000000
Internal error: Oops: 80000206 [#1] SMP ARM
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.0.0-rc7-koelsch-05861-g1fc9fdd4add4f783 #1046
Hardware name: Generic R8A7791 (Flattened Device Tree)
task: eec359c0 ti: eec54000 task.ti: eec54000
PC is at 0x0
LR is at spi_transfer_one_message+0x1cc/0x1f0
Make the master->handle_err() callback optional to avoid the crash.
Also fix a spelling mistake in the callback documentation while we're at
it.
Fixes: b716c4ffc6a2b0bf ("spi: introduce master->handle_err() callback")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
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The TI CC2521 is an RF power amplifier that is designed to interface
with the CC2520. Conveniently, it directly interfaces with the CC2520
and does not require any pins to be connected to a
microcontroller/processor. Adding a CC2591 increases the CC2520's range,
which is useful for border router and other wall-powered applications.
Using the CC2591 with the CC2520 requires configuring the CC2520 GPIOs
that are connected to the CC2591 to correctly set the CC2591 into TX and
RX modes. Further, TI recommends that the CC2520_TXPOWER and
CC2520_AGCCTRL1 registers are set differently to maximize the CC2591's
performance. These settings are covered in TI Application Note AN065.
This patch adds an optional `amplified` field to the cc2520 entry in the
device tree. If present, the CC2520 will be configured to operate with a
CC2591.
The expected pin mapping is:
CC2520 GPIO0 --> CC2591 EN
CC2520 GPIO5 --> CC2591 PAEN
Signed-off-by: Brad Campbell <bradjc5@gmail.com>
Acked-by: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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All SPI drivers have been converted from legacy suspend/resume callbacks to
dev_pm_ops. So we can finally remove support for legacy PM from the SPI
core.
Since there aren't any special bus specific things to do during
suspend/resume and since the PM core will automatically fallback directly to
using the device's PM ops if no bus PM ops are specified there is no need to
have any special SPI bus PM ops.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
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This callback would be useful to handle an error that occurs in the generic
implementation of transfer_one_message(). The good candidate for this is to
drain FIFO and / or to terminate DMA transfers when timeout happened.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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alway -> always
Signed-off-by: Marcin Bis <marcin@bis.org.pl>
Signed-off-by: Mark Brown <broonie@kernel.org>
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This patch adds support for setting the xtal trim register. Some at86rf2xx
transceiver boards needs fine tuning the xtal capacitor.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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Move the include of mach/dma.h to the legacy PXA DMA code where it is used.
This enables building spi-pxa2xx on ARM64.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
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The MSIOF controller has DTDL and SYNCDL in SITMDR1 register. So,
this patch adds new properties like the following commit:
d0fb47a5237d8b9576113568bacfd27892308b62
(spi: fsl-espi: Configure FSL eSPI CSBEF and CSAFT)
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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If we are using the standard SPI message pump (which all drivers should be
transitioning over to) then special case the message enqueue and instead of
starting the worker thread to push messages to the hardware do so in the
context of the caller if the controller is idle. This avoids a context
switch in the common case where the controller has a single user in a
single thread, for short PIO transfers there may be no need to context
switch away from the calling context to complete the transfer.
The code is a bit more complex than is desirable in part due to the need
to handle drivers not using the standard queue and in part due to handling
the various combinations of bus locking and asynchronous submission in
interrupt context.
It is still suboptimal since it will still wake the message pump for each
transfer in order to schedule idling of the hardware and if multiple
contexts are using the controller simultaneously a caller may end up
pumping a message for some random other thread rather than for itself,
and if the thread ends up deferring due to another context idling the
hardware then it will just busy wait. It can, however, have the benefit
of aggregating power up and down of the hardware when a caller performs
a series of transfers back to back without any need for the use of
spi_async().
Signed-off-by: Mark Brown <broonie@kernel.org>
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This adds the function spi_transfer_is_last() which can be used by
drivers to know whether a given transfer is the last one in the
current message.
Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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That field has been deprecated in favour of getting the necessary
information from ACPI/DT.
However, we still need to deal systems that are PCI only (no ACPI to back
up). In order to support such systems, we allow the DMA filter function and
its corresponding parameter via pxa2xx_spi_master platform data. Then when
the pxa2xx_spi_dma_setup() doesn't find the channel via ACPI, it falls back
to use the given filter function.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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Device tree is not enabled in some architecture where gpio
driver mcp23s08 is still required.
v2-changes:
- Parse device tree properties into platform data other than
individual variables.
v3-changes:
- Use of_node in gpio_chip device structure, because the
struct device * always has an of_node which is NULL when
OF is not used.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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These are all arguments or fields that got added without updating the
kerneldoc comments.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Add DMA support to the MSIOF driver using platform data.
As MSIOF DMA is limited to 32-bit words (requiring byte/wordswapping for
smaller wordsizes), and the group length is limited to 256 words, DMA is
performed on two fixed pages, allocated and mapped at driver initialization
time.
Performance figures (in Mbps) on r8a7791/koelsch at different SPI clock
frequencies for 1024-byte and 4096-byte transfers:
1024 bytes 4096 bytes
- 3.25 MHz: PIO 2.1, DMA 2.6 | PIO 2.8, DMA 3.1
- 6.5 MHz: PIO 3.2, DMA 4.4 | PIO 5.0, DMA 5.9
- 13 MHz: PIO 4.2, DMA 6.6 | PIO 8.2, DMA 10.7
- 26 MHz: PIO 5.9, DMA 10.4 | PIO 12.4, DMA 18.4
Note that DMA is only faster than PIO for transfers that exceed the FIFO
size (typically 64 words / 256 bytes).
Also note that large transfers (larger than the group length for DMA, or
larger than the FIFO size for PIO), should use cs-gpio (with the
appropriate pinmux setup), as the hardware chipselect will be deasserted in
between chunks.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
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This patch adds the driver support for the cc2520 radio.
Driver support:
- Tx and Rx of IEEE-802.15.4 packets
- Energy Detection on channel
- Setting the Channel for the radio. [b/w 11 - 26 channels]
- Start and Stop the radio
- h/w address filtering
Signed-off-by: Varka Bhadram <varkab@cdac.in>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The 16-bit DMA support doesn't fit well within the SPI core DMA framework,
as it needs to manage its own double-sized temporary buffers, for handling
the interleaved data.
Remove it, as there is no in-tree board code that sets
rspi_plat_data.dma_width_16bit.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
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This patch removes the platform data for the irq_type. We use instead
the irq_get_trigger_type function to get these flags which should
already configured by the interrupt controller.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Spi v3 controller is not only used on Blackfin. So rename it
and use ioread/iowrite api to make it work on other platform.
Signed-off-by: Scott Jiang <scott.jiang.linux@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
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spi_bitbang_stop() never fails, so make it return void.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
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This patch fix spelling typo in Documentation/DocBook.
It is because .html and .xml files are generated by make htmldocs,
I have to fix a typo within the source files.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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We cannot unconditionally use dma_map_single() to map data for use with
SPI since transfers may exceed a page and virtual addresses may not be
provided with physically contiguous pages. Further, addresses allocated
using vmalloc() need to be mapped differently to other addresses.
Currently only the MXS driver handles all this, a few drivers do handle
the possibility that buffers may not be physically contiguous which is
the main potential problem but many don't even do that. Factoring this
out into the core will make it easier for drivers to do a good job so if
the driver is using the core DMA code then generate a scatterlist
instead of mapping to a single address so do that.
This code is mainly based on a combination of the existing code in the MXS
and PXA2xx drivers. In future we should be able to extend it to allow the
core to concatenate adjacent transfers if they are compatible, improving
performance.
Currently for simplicity clients are not allowed to use the scatterlist
when they do DMA mapping, in the future the existing single address
mappings will be replaced with use of the scatterlist most likely as
part of pre-verifying transfers.
This change makes it mandatory to use scatterlists when using the core DMA
mapping so update the s3c64xx driver to do this when used with dmaengine.
Doing so makes the code more ugly but it is expected that the old s3c-dma
code can be removed very soon.
Signed-off-by: Mark Brown <broonie@linaro.org>
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It is fairly common for SPI devices to require that one or both transfer
directions is always active. Currently drivers open code this in various
ways with varying degrees of efficiency. Start factoring this out by
providing flags SPI_MASTER_MUST_TX and SPI_MASTER_MUST_RX. These will cause
the core to provide buffers for the requested direction if none are
specified in the underlying transfer.
Currently this is fairly inefficient since we actually allocate a data
buffer which may get large, support for mapping transfers using a
scatterlist will allow us to avoid this for DMA based transfers.
Signed-off-by: Mark Brown <broonie@linaro.org>
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The process of DMA mapping buffers for SPI transfers does not vary between
devices so in order to save duplication of code in drivers this can be
factored out into the core, allowing it to be integrated with the work that
is being done on factoring out the common elements from the data path
including more sharing of dmaengine code.
In order to use this masters need to provide a can_dma() operation and while
the hardware is prepared they should ensure that DMA channels are provided
in tx_dma and rx_dma. The core will then ensure that the buffers are mapped
for DMA prior to calling transfer_one_message().
Currently the cleanup on error is not complete, this needs to be improved.
Signed-off-by: Mark Brown <broonie@linaro.org>
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The transfer_one_message callback handles messages, not transfers.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Explicitly note the transfer_one and transfer_one_message are mutually
exclusive, to make the text a little more newcomers friendly.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Mark Brown <broonie@linaro.org>
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The documentation for spi_master.set_cs() says:
assert or deassert chip select, true to assert
i.e. its "enable" parameter uses assertion-level logic.
This does not match the implementation of spi_set_cs(), which calls
spi_master.set_cs() with the wanted logic level of the chip select line,
which depends on the polarity of the chip select signal.
Correct the documentation to match the implementation.
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
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spi_write_then_read() takes a "void *" for rxbuf, so there's no need to
cast the buffer pointer to "u8 *".
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Trent Piepho observed that since the current realistic maximum number of
data lines is four we can pack the spi_transfer struct more efficiently
if we use a bitfield for the number of bits, allowing the fields to fit
in a single byte along with cs_change.
If space becomes an issue further optimiation is possible by only using
the constants and packing the values chosen for them.
Reported-by: Trent Piepho <tpiepho@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
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fiq.h contains only a function declaration and is not used by anyone
else. Move the declaration to the driver header file and remove the
unnecessary platform dependency from the driver.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Now that spi_device->mode is a u16, the chip_select, bits_per_mode,
and mode fields pack poorly, taking 8 bytes: four data and four
padding. By moving (u8)bits_per_word up one position, to after
(u8)chip_select, they pack better and only use 4 bytes.
Signed-off-by: Trent Piepho <tpiepho@gmail.com>
Reviewed-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>g
Signed-off-by: Mark Brown <broonie@linaro.org>
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Commit 20bc4d5d565159eb2b942bf4b7fae86fba94e32c
(gpio: 74x164: Add support for the daisy-chaining) introduce check
for DT for the driver, so driver cannot be used without DT.
There are no in-tree users of this driver, so remove non-DT support
completely.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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The loops which SPI controller drivers use to process the list of transfers
in a spi_message are typically very similar and have some error prone areas
such as the handling of /CS. Help simplify drivers by factoring this code
out into the core - if drivers provide a transfer_one() function instead
of a transfer_one_message() function the core will handle processing at the
message level.
/CS can be controlled by either setting cs_gpio or providing a set_cs
function. If this is not possible for hardware reasons then both can be
omitted and the driver should continue to implement manual /CS handling.
This is a first step in refactoring and it is expected that there will be
further enhancements, for example factoring out of the mapping of transfers
for DMA and the initiation and completion of interrupt driven transfers.
Signed-off-by: Mark Brown <broonie@linaro.org>
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Many SPI drivers perform setup and tear down on every message, usually
doing things like DMA mapping the message. Provide hooks for them to use
to provide such operations.
This is of limited value for drivers that implement transfer_one_message()
but will be of much greater utility with future factoring out of standard
implementations of that function.
Signed-off-by: Mark Brown <broonie@linaro.org>
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This patch adds a new spi_w8r16be() helper, which is similar to spi_w8r16()
except that it converts the read data word from big endian to native endianness
before returning it. The reason for introducing this new helper is that for SPI
slave devices it is quite common that the read 16 bit data word is in big
endian. So users of spi_w8r16() have to convert the result to native endianness
manually. A second reason is that in this case the endianness of the return
value of spi_w8r16() depends on its sign. If it is negative (i.e. a error code)
it is already in native endianness, if it is positive it is in big endian. The
sparse code checker doesn't like this kind of mixed endianness and special
annotations are necessary to keep it quiet (E.g. casting to be16 using __force).
Doing the conversion to native endianness in the helper function does not
require such annotations since we are not mixing different endiannesses in the
same variable.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Help simplify the cleanup code for SPI master drivers by providing a
managed master registration function, ensuring that the master is
automatically unregistered whenever the device is unbound.
Signed-off-by: Mark Brown <broonie@linaro.org>
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