mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-12-30 22:57:14 -05:00
3ae4f3aac0
R-Car GPIO controller provides two interfaces to set GPIO line output signal state, and for a particular GPIO line the selected interface is determined by OUTDTSEL bit value. At the moment the driver supports only one of two interfaces, namely OUTDT General Output Register is used to control the output signal. While this selection is the default one on reset, it is not explicitly configured on probe, thus it might be possible that kernel and userspace consumers of a GPIO won't be able to set the wanted GPIO output signal. Below is a simple test case to reproduce the described problem and verify this fix in the kernel on H3 ULCB by setting non-default OUTDTSEL configuration from a bootloader: u-boot > mw.l 0xe6055440 0x3000 1 ... userspace > echo default-on > /sys/devices/platform/leds/leds/led5/trigger userspace > echo default-on > /sys/devices/platform/leds/leds/led6/trigger Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.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.