commit 6098475d4cb48d821bdf453c61118c56e26294f0 upstream.
Currently we have a global spi_add_lock which we take when adding new
devices so that we can check that we're not trying to reuse a chip
select that's already controlled. This means that if the SPI device is
itself a SPI controller and triggers the instantiation of further SPI
devices we trigger a deadlock as we try to register and instantiate
those devices while in the process of doing so for the parent controller
and hence already holding the global spi_add_lock. Since we only care
about concurrency within a single SPI bus move the lock to be per
controller, avoiding the deadlock.
This can be easily triggered in the case of spi-mux.
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Hardik Gohil <hgohil@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 029b42d8519cef70c4fb5fcaccd08f1053ed2bf0 ]
Provide a macro to filter all SPI_MODE_0,1,2,3 mode in one run.
The latest SPI framework will parse the devicetree in following call
sequence: of_register_spi_device() -> of_spi_parse_dt()
So, driver do not need to pars the devicetree and will get prepared
flags in the probe.
On one hand it is good far most drivers. On other hand some drivers need to
filter flags provide by SPI framework and apply know to work flags. This drivers
may use SPI_MODE_X_MASK to filter MODE flags and set own, known flags:
spi->flags &= ~SPI_MODE_X_MASK;
spi->flags |= SPI_MODE_0;
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20201027095724.18654-2-o.rempel@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Stable-dep-of: 6d710b769c1f ("serial: sc16is7xx: add check for unsupported SPI modes during probe")
Signed-off-by: Sasha Levin <sashal@kernel.org>
