spi: mux: switch to use spi_alloc_host()

Switch to use modern name function spi_alloc_host().

No functional changed.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20230823033003.3407403-15-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Replace all spi->chip_select and spi->cs_gpiod references with function call

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>

spi: mux: Fix mux interaction with fast path optimisations

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: ae7d2346dc89 ("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>

spi-mux: Fix false-positive lockdep splats

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>

spi: spi-mux: Add module info needed for autoloading

With the spi device table udev can autoload the spi-mux module in
the presence of an spi-mux device.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210721095321.2165453-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-mux: 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/20200901152713.18629-6-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: mux: repair mux usage

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: e9e40543ad5b ("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>

spi: Add generic SPI multiplexer

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>