3b52093dc9
The current use of mode flags to us SPI_MODE_3 and SPI_CS_HIGH is fragile: it overwrites anything already assigned by the SPI core. Change it thusly: - Just |= the SPI_MODE_3 so we keep other flags - Assign ^= SPI_CS_HIGH since we might be active high already, and that is usually the case with GPIOs used for chip select, even if they are in practice active low. Add a comment clarifying why ^= SPI_CS_HIGH is the right choice here. Reported-by: Mark Brown <broonie@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20191204225731.20306-1-linus.walleij@linaro.org Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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.