[PATCH AUTOSEL 5.0 129/262] gpio: of: Apply regulator-gpio quirk only to enable-gpios

* [PATCH AUTOSEL 5.0 129/262] gpio: of: Apply regulator-gpio quirk only to enable-gpios
       [not found] <20190327180158.10245-1-sashal@kernel.org>
@ 2019-03-27 17:59 ` Sasha Levin
  2019-03-27 18:00 ` [PATCH AUTOSEL 5.0 170/262] drm: rcar-du: add missing of_node_put Sasha Levin
                   ` (4 subsequent siblings)
  5 siblings, 0 replies; 6+ messages in thread
From: Sasha Levin @ 2019-03-27 17:59 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Marek Vasut, Geert Uytterhoeven, Jan Kotas, Linus Walleij,
	Mark Brown, Wolfram Sang, linux-renesas-soc, Sasha Levin,
	linux-gpio

From: Marek Vasut <marek.vasut+renesas@gmail.com>

[ Upstream commit 0e7d6f94016407fd7e1ae472e254d64d4454e9c8 ]

Since commit d6cd33ad7102 ("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 commit a603a2b8d86e
("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpio/gpiolib-of.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index a6e1891217e2..30542a10014f 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -84,6 +84,7 @@ static void of_gpio_flags_quirks(struct device_node *np,
 	 * Note that active low is the default.
 	 */
 	if (IS_ENABLED(CONFIG_REGULATOR) &&
+	    !strcmp(propname, "enable-gpio") &&
 	    (of_device_is_compatible(np, "regulator-fixed") ||
 	     of_device_is_compatible(np, "reg-fixed-voltage") ||
 	     of_device_is_compatible(np, "regulator-gpio"))) {
-- 
2.19.1


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