[PATCH 09/11] gpiolib: export function to get struct gpio_desc from index

[Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>]

For use in legacy non-DT board code, let's introduce a function that
translates an absolute GPIO number into the corresponding GPIO descriptor.

Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
 drivers/gpio/gpiolib.c        | 26 ++++++++++++++++++++------
 include/linux/gpio/consumer.h | 10 ++++++++++
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5d5458374869..146eaf9af138 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -642,6 +642,24 @@ static int gpiodesc_request_one(struct gpio_desc *desc, unsigned long lflags,
 	return err;
 }
 
+struct gpio_desc *gpiod_request_one(unsigned gpio,
+				    unsigned long flags, const char *label)
+{
+	struct gpio_desc *desc = gpio_to_desc(gpio);
+	int ret;
+
+	if (!desc)
+		return ERR_PTR(-ENODEV);
+
+	ret = gpiodesc_request_one(desc, 0, flags, label);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(gpio_request_one);
+
+
 /**
  * gpio_request_one - request a single GPIO with initial configuration
  * @gpio:	the GPIO number
@@ -650,15 +668,11 @@ static int gpiodesc_request_one(struct gpio_desc *desc, unsigned long lflags,
  */
 int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
 {
-	struct gpio_desc *desc = gpio_to_desc(gpio);
-
-	if (!desc)
-		return -ENODEV;
-
-	return gpiodesc_request_one(desc, 0, flags, label);
+	return PTR_ERR_OR_ZERO(gpiod_request_one(gpio, flags, label));
 }
 EXPORT_SYMBOL_GPL(gpio_request_one);
 
+
 /**
  * gpio_request_array - request multiple GPIOs in a single call
  * @array:	array of the 'struct gpio'
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 64366a6f3302..f0d5bf7b255b 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -97,6 +97,9 @@ int gpiod_set_array_value(unsigned int array_size,
 			  struct gpio_array *array_info,
 			  unsigned long *value_bitmap);
 
+struct gpio_desc *gpiod_request_one(unsigned gpio,
+				    unsigned long flags, const char *label);
+
 #else
 
 static inline int gpiod_set_config(struct gpio_desc *desc, unsigned long config)
@@ -186,6 +189,13 @@ static inline int gpiod_set_array_value(unsigned int array_size,
 	return 0;
 }
 
+static inline
+struct gpio_desc *gpiod_request_one(unsigned gpio,
+				    unsigned long flags, const char *label)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 #endif
 
 static inline struct gpio_desc *dev_gpiod_get(struct device *dev,
-- 
2.39.2