Like other SPI controller flags, bits_per_word_mask may be used by a
peripheral driver, so it needs to reflect the capabilities of the
underlying controller.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240708-spi-mux-fix-v1-3-6c8845193128@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Adding spi_optimize_message() broke the spi-mux driver because it
calls spi_async() from it's transfer_one_message() callback. This
resulted in passing an incorrectly optimized message to the controller.
For example, if the underlying controller has an optimize_message()
callback, this would have not been called and can cause a crash when
the underlying controller driver tries to transfer the message.
Also, since the spi-mux driver swaps out the controller pointer by
replacing msg->spi, __spi_unoptimize_message() was being called with a
different controller than the one used in __spi_optimize_message(). This
could cause a crash when attempting to free the message resources when
__spi_unoptimize_message() is called in spi_finalize_current_message()
since it is being called with a controller that did not allocate the
resources.
This is fixed by adding a defer_optimize_message flag for controllers.
This flag causes all of the spi_[maybe_][un]optimize_message() calls to
be a no-op (other than attaching a pointer to the spi device to the
message).
This allows the spi-mux driver to pass an unmodified message to
spi_async() in spi_mux_transfer_one_message() after the spi device has
been swapped out. This causes __spi_optimize_message() and
__spi_unoptimize_message() to be called only once per message and with
the correct/same controller in each case.
Reported-by: Oleksij Rempel <o.rempel@pengutronix.de>
Closes: https://lore.kernel.org/linux-spi/Zn6HMrYG2b7epUxT@pengutronix.de/
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Closes: https://lore.kernel.org/linux-spi/20240628-awesome-discerning-bear-1621f9-mkl@pengutronix.de/
Fixes: 7b1d87af14 ("spi: add spi_optimize_message() APIs")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240708-spi-mux-fix-v1-2-6c8845193128@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
In some cases SPI child devices behind spi-mux require different
settings like: max_speed_hz, mode and bits_per_word.
Typically the slave device driver puts the settings in place and calls
spi_setup() once during probe and assumes they stay in place for all
following spi transfers.
However spi-mux forwarded spi_setup() -call to SPI master driver only
when slave driver calls spi_setup(). If second slave device was
accessed meanwhile and that driver called spi_setup(), the
settings did not change back to the first spi device.
In case of wrong max_speed_hz this caused spi trasfers to fail.
This commit adds spi_setup() call after mux is changed. This way
the right device specific parameters are set to the master driver.
The fix has been tested by using custom hardware and debugging
spi master driver speed settings.
Co-authored-by: Petri Tauriainen <petri.tauriainen@bittium.com>
Signed-off-by: Heikki Keranen <heikki.keranen@bittium.com>
Link: https://lore.kernel.org/r/20240422114150.84426-1-heikki.keranen@bittium.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Supporting multi-cs in spi drivers would require the chip_select & cs_gpiod
members of struct spi_device to be an array. But changing the type of these
members to array would break the spi driver functionality. To make the
transition smoother introduced four new APIs to get/set the
spi->chip_select & spi->cs_gpiod and replaced all spi->chip_select and
spi->cs_gpiod references with get or set API calls.
While adding multi-cs support in further patches the chip_select & cs_gpiod
members of the spi_device structure would be converted to arrays & the
"idx" parameter of the APIs would be used as array index i.e.,
spi->chip_select[idx] & spi->cs_gpiod[idx] respectively.
Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
Acked-by: Heiko Stuebner <heiko@sntech.de> # Rockchip drivers
Reviewed-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org> # Aspeed driver
Reviewed-by: Dhruva Gole <d-gole@ti.com> # SPI Cadence QSPI
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> # spi-stm32-qspi
Acked-by: William Zhang <william.zhang@broadcom.com> # bcm63xx-hsspi driver
Reviewed-by: Serge Semin <fancer.lancer@gmail.com> # DW SSI part
Link: https://lore.kernel.org/r/167847070432.26.15076794204368669839@mailman-core.alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>
The spi-mux driver is rather too clever and attempts to resubmit any
message that is submitted to it to the parent controller with some
adjusted callbacks. This does not play at all nicely with the fast
path which now sets flags on the message indicating that it's being
handled through the fast path, we see async messages flagged as being on
the fast path. Ideally the spi-mux code would duplicate the message but
that's rather invasive and a bit fragile in that it relies on the mux
knowing which fields in the message to copy. Instead teach the core
that there are controllers which can't cope with the fast path and have
the mux flag itself as being such a controller, ensuring that messages
going via the mux don't get partially handled via the fast path.
This will reduce the performance of any spi-mux connected device since
we'll now always use the thread for both the actual controller and the
mux controller instead of just the actual controller but given that we
were always hitting the slow path anyway it's hopefully not too much of
an additional cost and it allows us to keep the fast path.
Fixes: ae7d2346dc ("spi: Don't use the message queue if possible in spi_sync")
Reported-by: Casper Andersson <casper.casan@gmail.com>
Tested-by: Casper Andersson <casper.casan@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220901120732.49245-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
io_mutex is taken by spi_setup() and spi-mux's .setup() callback calls
spi_setup() which results in a nested lock of io_mutex.
add_lock is taken by spi_add_device(). The device_add() call in there
can result in calling spi-mux's .probe() callback which registers its
own spi controller which in turn results in spi_add_device() being
called again.
To fix this initialize the controller's locks already in
spi_alloc_controller() to give spi_mux_probe() a chance to set the
lockdep subclass.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211013133710.2679703-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
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/20200901152713.18629-6-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
It is not valid to cache/short out selection of the mux.
mux_control_select() only locks the mux until mux_control_deselect()
is called. mux_control_deselect() may put the mux in some low power
state or some other user of the mux might select it for other purposes.
These things are probably not happening in the original setting where
this driver was developed, but it is said to be a generic SPI mux.
Also, the mux framework will short out the actual low level muxing
operation when/if that is possible.
Fixes: e9e40543ad ("spi: Add generic SPI multiplexer")
Signed-off-by: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20200525104352.26807-1-peda@axentia.se
Signed-off-by: Mark Brown <broonie@kernel.org>
Add a SPI device driver that sits in-band and provides a SPI controller
which supports chip selects via a mux-control. This enables extra SPI
devices to be connected with limited native chip selects.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200204032838.20739-3-chris.packham@alliedtelesis.co.nz
Signed-off-by: Mark Brown <broonie@kernel.org>
