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authorLinus Walleij <linus.walleij@linaro.org>2017-12-30 16:26:36 +0100
committerLinus Walleij <linus.walleij@linaro.org>2018-01-12 11:05:24 +0100
commita603a2b8d86ee93ee2107da8ca75fd854fd4ff32 (patch)
treea8c64d824f251cb413387858a3a1c235710b6d6c /drivers/gpio/gpiolib-of.c
parentgpio: Export devm_gpiod_get_from_of_node() for consumers (diff)
downloadlinux-dev-a603a2b8d86ee93ee2107da8ca75fd854fd4ff32.tar.xz
linux-dev-a603a2b8d86ee93ee2107da8ca75fd854fd4ff32.zip
gpio: of: Add special quirk to parse regulator flags
While most GPIOs are indicated to be active low or open drain using their twocell flags, we have legacy regulator bindings to take into account. Add a quirk respecting the special boolean active-high and open drain flags when parsing regulator nodes for GPIOs. This makes it possible to get rid of duplicated inversion semantics handling in the regulator core and any regulator drivers parsing and handling this separately. Unfortunately the old regulator inversion semantics are specified such that the presence or absence of "enable-active-high" solely controls the semantics, so we cannot deprecate this in favor of the phandle-provided inversion flag, instead any such phandle inversion flag provided in the second cell of a GPIO handle must be actively ignored, so we print a warning to contain the situation and make things easy for the users. Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/gpio/gpiolib-of.c')
-rw-r--r--drivers/gpio/gpiolib-of.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index d2a6656b82cb..71ba008b7f46 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -56,6 +56,42 @@ static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
return gpiochip_get_desc(chip, ret);
}
+static void of_gpio_flags_quirks(struct device_node *np,
+ enum of_gpio_flags *flags)
+{
+ /*
+ * Some GPIO fixed regulator quirks.
+ * Note that active low is the default.
+ */
+ if (IS_ENABLED(CONFIG_REGULATOR) &&
+ (of_device_is_compatible(np, "reg-fixed-voltage") ||
+ of_device_is_compatible(np, "regulator-gpio"))) {
+ /*
+ * The regulator GPIO handles are specified such that the
+ * presence or absence of "enable-active-high" solely controls
+ * the polarity of the GPIO line. Any phandle flags must
+ * be actively ignored.
+ */
+ if (*flags & OF_GPIO_ACTIVE_LOW) {
+ pr_warn("%s GPIO handle specifies active low - ignored\n",
+ of_node_full_name(np));
+ *flags &= ~OF_GPIO_ACTIVE_LOW;
+ }
+ if (!of_property_read_bool(np, "enable-active-high"))
+ *flags |= OF_GPIO_ACTIVE_LOW;
+ }
+ /*
+ * Legacy open drain handling for fixed voltage regulators.
+ */
+ if (IS_ENABLED(CONFIG_REGULATOR) &&
+ of_device_is_compatible(np, "reg-fixed-voltage") &&
+ of_property_read_bool(np, "gpio-open-drain")) {
+ *flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN);
+ pr_info("%s uses legacy open drain flag - update the DTS if you can\n",
+ of_node_full_name(np));
+ }
+}
+
/**
* of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
* @np: device node to get GPIO from
@@ -93,6 +129,8 @@ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
if (IS_ERR(desc))
goto out;
+ of_gpio_flags_quirks(np, flags);
+
pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n",
__func__, propname, np, index,
PTR_ERR_OR_ZERO(desc));