9b2aa765fb
[ Upstream commit d5d933f09ac326aebad85bfb787cc786ad477711 ]
The hardware (except for the ROCKCHIP_SPI_VER2_TYPE2 version) does not
support active-high native chip selects. However if such a CS is configured
the core does not error as it normally should, because the
'ctlr->use_gpio_descriptors = true' line in rockchip_spi_probe() makes the
core set SPI_CS_HIGH in ctlr->mode_bits.
In such a case the spi-rockchip driver operates normally but produces an
active-low chip select signal without notice.
There is no provision in the current core code to handle this
situation. Fix by adding a check in the ctlr->setup function (similarly to
what spi-atmel.c does).
This cannot be done reading the SPI_CS_HIGH but in ctlr->mode_bits because
that bit gets always set by the core for master mode (see above).
Fixes: eb1262e3cc8b ("spi: spi-rockchip: use num-cs property and ctlr->enable_gpiods")
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://lore.kernel.org/r/20220421213251.1077899-1-luca.ceresoli@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.