gpio: Add the devm_fwnode_get_index_gpiod_from_child() helper

devm_fwnode_get_gpiod_from_child() currently allows GPIO users to
request a GPIO that is defined in a child fwnode instead of directly in
the device fwnode.
Extend this API by adding the devm_fwnode_get_index_gpiod_from_child()
helper which does the same except you can also specify an index in case
the 'xx-gpios' property describe several GPIOs.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 37 insertions, 23 deletions

diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
index cd1bd1c3d2c0..b2bbcaae6a1f 100644
--- a/drivers/gpio/devres.c
+++ b/drivers/gpio/devres.c
@@ -123,10 +123,11 @@ struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
 EXPORT_SYMBOL(devm_gpiod_get_index);
 
 /**
- * devm_fwnode_get_gpiod_from_child - get a GPIO descriptor from a device's
- *                                    child node
+ * devm_fwnode_get_index_gpiod_from_child - get a GPIO descriptor from a
+ *                                          device's child node
  * @dev:        GPIO consumer
  * @con_id:     function within the GPIO consumer
+ * @index:      index of the GPIO to obtain in the consumer
  * @child:      firmware node (child of @dev)
  * @flags:      GPIO initialization flags
  *
@@ -136,11 +137,11 @@ EXPORT_SYMBOL(devm_gpiod_get_index);
  * On successfull request the GPIO pin is configured in accordance with
  * provided @flags.
  */
-struct gpio_desc *devm_fwnode_get_gpiod_from_child(struct device *dev,
-                                                   const char *con_id,
-                                                   struct fwnode_handle *child,
-                                                   enum gpiod_flags flags,
-                                                   const char *label)
+struct gpio_desc *devm_fwnode_get_index_gpiod_from_child(struct device *dev,
+                                                const char *con_id, int index,
+                                                struct fwnode_handle *child,
+                                                enum gpiod_flags flags,
+                                                const char *label)
 {
         static const char * const suffixes[] = { "gpios", "gpio" };
         char prop_name[32]; /* 32 is max size of property name */
@@ -161,7 +162,8 @@ struct gpio_desc *devm_fwnode_get_gpiod_from_child(struct device *dev,
                         snprintf(prop_name, sizeof(prop_name), "%s",
                                                                suffixes[i]);
 
-                desc = fwnode_get_named_gpiod(child, prop_name, flags, label);
+                desc = fwnode_get_named_gpiod(child, prop_name, index, flags,
+                                              label);
                 if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
                         break;
         }
@@ -175,7 +177,7 @@ struct gpio_desc *devm_fwnode_get_gpiod_from_child(struct device *dev,
 
         return desc;
 }
-EXPORT_SYMBOL(devm_fwnode_get_gpiod_from_child);
+EXPORT_SYMBOL(devm_fwnode_get_index_gpiod_from_child);
 
 /**
  * devm_gpiod_get_index_optional - Resource-managed gpiod_get_index_optional()
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 20c6c51cbe10..5e5d48c3512c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3309,6 +3309,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_index);
  * fwnode_get_named_gpiod - obtain a GPIO from firmware node
  * @fwnode:     handle of the firmware node
  * @propname:   name of the firmware property representing the GPIO
+ * @index:      index of the GPIO to obtain in the consumer
  * @dflags:     GPIO initialization flags
  *
  * This function can be used for drivers that get their configuration
@@ -3324,7 +3325,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_index);
  * In case of error an ERR_PTR() is returned.
  */
 struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
-                                         const char *propname,
+                                         const char *propname, int index,
                                          enum gpiod_flags dflags,
                                          const char *label)
 {
@@ -3340,8 +3341,8 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
         if (is_of_node(fwnode)) {
                 enum of_gpio_flags flags;
 
-                desc = of_get_named_gpiod_flags(to_of_node(fwnode), propname, 0,
-                                                &flags);
+                desc = of_get_named_gpiod_flags(to_of_node(fwnode), propname,
+                                                index, &flags);
                 if (!IS_ERR(desc)) {
                         active_low = flags & OF_GPIO_ACTIVE_LOW;
                         single_ended = flags & OF_GPIO_SINGLE_ENDED;
@@ -3349,7 +3350,7 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
         } else if (is_acpi_node(fwnode)) {
                 struct acpi_gpio_info info;
 
-                desc = acpi_node_get_gpiod(fwnode, propname, 0, &info);
+                desc = acpi_node_get_gpiod(fwnode, propname, index, &info);
                 if (!IS_ERR(desc))
                         active_low = info.polarity == GPIO_ACTIVE_LOW;
         }
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index f32f49e96c0b..ea9b01d40017 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -135,14 +135,14 @@ int desc_to_gpio(const struct gpio_desc *desc);
 struct fwnode_handle;
 
 struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
-                                         const char *propname,
+                                         const char *propname, int index,
                                          enum gpiod_flags dflags,
                                          const char *label);
-struct gpio_desc *devm_fwnode_get_gpiod_from_child(struct device *dev,
-                                                   const char *con_id,
-                                                   struct fwnode_handle *child,
-                                                   enum gpiod_flags flags,
-                                                   const char *label);
+struct gpio_desc *devm_fwnode_get_index_gpiod_from_child(struct device *dev,
+                                                const char *con_id, int index,
+                                                struct fwnode_handle *child,
+                                                enum gpiod_flags flags,
+                                                const char *label);
 #else /* CONFIG_GPIOLIB */
 
 static inline int gpiod_count(struct device *dev, const char *con_id)
@@ -417,7 +417,7 @@ struct fwnode_handle;
 
 static inline
 struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
-                                         const char *propname,
+                                         const char *propname, int index,
                                          enum gpiod_flags dflags,
                                          const char *label)
 {
@@ -425,17 +425,28 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
 }
 
 static inline
+struct gpio_desc *devm_fwnode_get_index_gpiod_from_child(struct device *dev,
+                                                const char *con_id, int index,
+                                                struct fwnode_handle *child,
+                                                enum gpiod_flags flags,
+                                                const char *label)
+{
+        return ERR_PTR(-ENOSYS);
+}
+
+#endif /* CONFIG_GPIOLIB */
+
+static inline
 struct gpio_desc *devm_fwnode_get_gpiod_from_child(struct device *dev,
                                                    const char *con_id,
                                                    struct fwnode_handle *child,
                                                    enum gpiod_flags flags,
                                                    const char *label)
 {
-        return ERR_PTR(-ENOSYS);
+        return devm_fwnode_get_index_gpiod_from_child(dev, con_id, 0, child,
+                                                      flags, label);
 }
 
-#endif /* CONFIG_GPIOLIB */
-
 #if IS_ENABLED(CONFIG_GPIOLIB) && IS_ENABLED(CONFIG_GPIO_SYSFS)
 
 int gpiod_export(struct gpio_desc *desc, bool direction_may_change);