[PATCH 6/7] gpiolib: implement of_gpio_get_chip_by_alias

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Rockchip pinctrl binding can configure GPIO direction, so let's add a
function that returns a gpio_chip that can be used for this.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/gpio/gpiolib.c | 19 +++++++++++++++++++
 include/gpio.h         |  6 ++++++
 2 files changed, 25 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 520ffed2eefb..f34dce0e98c6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1057,6 +1057,25 @@ struct gpio_chip *gpio_get_chip_by_dev(struct device *dev)
 	return NULL;
 }
 
+struct gpio_chip *of_gpio_get_chip_by_alias(const char *alias)
+{
+	struct gpio_chip *chip;
+	struct device_node *np;
+
+	np = of_find_node_by_alias(NULL, alias);
+	if (!np)
+		return NULL;
+
+	of_device_ensure_probed(np);
+
+	list_for_each_entry(chip, &chip_list, list) {
+		if (dev_of_node(chip->dev) == np)
+			return chip;
+	}
+
+	return NULL;
+}
+
 int gpio_get_num(struct device *dev, int gpio)
 {
 	struct gpio_chip *chip;
diff --git a/include/gpio.h b/include/gpio.h
index 71896c9d6bdb..8c3eea73d8bb 100644
--- a/include/gpio.h
+++ b/include/gpio.h
@@ -36,6 +36,7 @@ void gpio_set_active(unsigned gpio, bool state);
 int gpio_is_active(unsigned gpio);
 int gpio_direction_active(unsigned gpio, bool state);
 struct gpio_chip *gpio_get_chip_by_dev(struct device *);
+struct gpio_chip *of_gpio_get_chip_by_alias(const char *alias);
 
 /**
  * gpio_poll_timeout_us - Poll till GPIO reaches requested active state
@@ -69,6 +70,11 @@ static inline struct gpio_chip *gpio_get_chip_by_dev(struct device *dev)
 	return NULL;
 }
 
+static struct gpio_chip *of_gpio_get_chip_by_alias(const char *alias)
+{
+	return NULL;
+}
+
 #define gpio_poll_timeout_us(gpio, val, timeout_us) (-ENOSYS)
 #endif
 
-- 
2.39.2