mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-07 19:30:30 +09:00
0e7d6f9401
Since commitd6cd33ad71("regulator: gpio: Convert to use descriptors") the GPIO regulator had inverted the polarity of the control GPIO. This problem manifested itself on systems with DT containing the following description (snippet from salvator-common.dtsi): gpios = <&gpio5 1 GPIO_ACTIVE_HIGH>; gpios-states = <1>; states = <3300000 1 1800000 0>; Prior to the aforementioned commit, the gpio-regulator code used gpio_request_array() to claim the GPIO(s) specified in the "gpios" DT node, while the commit changed that to devm_gpiod_get_index(). The legacy gpio_request_array() calls gpio_request_one() and then gpiod_request(), which parses the DT flags of the "gpios" node and populates the GPIO descriptor flags field accordingly. The new devm_gpiod_get_index() calls gpiod_get_index(), then of_find_gpio(), of_get_named_gpiod_flags() with flags != NULL, and then of_gpio_flags_quirks(). Since commita603a2b8d8("gpio: of: Add special quirk to parse regulator flags"), of_gpio_flags_quirks() contains a quirk for regulator-gpio which was never triggered by the legacy gpio_request_array() code path, but is triggered by devm_gpiod_get_index() code path. This quirk checks whether a GPIO is associated with a fixed or gpio-regulator and if so, checks two additional conditions. First, whether such GPIO is active-low, and if so, ignores the active-low flag. Second, whether the regulator DT node does have an "enable-active-high" property and if the property is NOT present, sets the GPIO flags as active-low. The second check triggers a problem, since it is applied to all GPIOs associated with a gpio-regulator, rather than only on the "enable" GPIOs, as the old code did. This changes the way the gpio-regulator interprets the DT description of the control GPIOs. The old code using gpio_request_array() explicitly parsed the "enable-active-high" DT property and only applied it to the GPIOs described in the "enable-gpios" DT node, and only if those were present. This patch fixes the quirk code by only applying the quirk to "enable-gpios", thus restoring the old behavior. Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Jan Kotas <jank@cadence.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Mark Brown <broonie@kernel.org> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com> Cc: linux-renesas-soc@vger.kernel.org To: linux-gpio@vger.kernel.org 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.