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413c601e8f
When using the device tree, which must be considered normal
these days, in order to get some kind of normal functionality
out of the PL022 users have to actively go into the device
tree and edit the SPI clients like this:
spi {
compatible = "arm,pl022";
num-cs = <1>;
cs-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
foo@0 {
compatible = "foo";
reg = <0>;
pl022,interface = <0>;
pl022,com-mode = <0>;
};
};
Otherwise the PL022 will come up as a client (slave) and
using polling mode. This is quite unintuitive and many users
will get their device trees wrong.
Alter the defaults such that we come up in host mode
(master) and use interrupt mode.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210328121530.1983081-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@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.