2 files changed, 27 insertions, 3 deletions
diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt
index 76546324e968..6ce544191ca6 100644
--- a/Documentation/gpio/consumer.txt
+++ b/Documentation/gpio/consumer.txt
@@ -53,7 +53,20 @@ with IS_ERR() (they will never return a NULL pointer). -ENOENT will be returned
 if and only if no GPIO has been assigned to the device/function/index triplet,
 other error codes are used for cases where a GPIO has been assigned but an error
 occurred while trying to acquire it. This is useful to discriminate between mere
-errors and an absence of GPIO for optional GPIO parameters.
+errors and an absence of GPIO for optional GPIO parameters. For the common
+pattern where a GPIO is optional, the gpiod_get_optional() and
+gpiod_get_index_optional() functions can be used. These functions return NULL
+instead of -ENOENT if no GPIO has been assigned to the requested function:
+
+
+	struct gpio_desc *gpiod_get_optional(struct device *dev,
+					     const char *con_id,
+					     enum gpiod_flags flags)
+
+	struct gpio_desc *gpiod_get_index_optional(struct device *dev,
+						   const char *con_id,
+						   unsigned int index,
+						   enum gpiod_flags flags)
 
 Device-managed variants of these functions are also defined:
 
@@ -65,6 +78,15 @@ Device-managed variants of these functions are also defined:
 					       unsigned int idx,
 					       enum gpiod_flags flags)
 
+	struct gpio_desc *devm_gpiod_get_optional(struct device *dev,
+						  const char *con_id,
+						  enum gpiod_flags flags)
+
+	struct gpio_desc * devm_gpiod_get_index_optional(struct device *dev,
+							const char *con_id,
+							unsigned int index,
+							enum gpiod_flags flags)
+
 A GPIO descriptor can be disposed of using the gpiod_put() function:
 
 	void gpiod_put(struct gpio_desc *desc)
diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt
index 18790c237977..31e0b5db55d8 100644
--- a/Documentation/gpio/driver.txt
+++ b/Documentation/gpio/driver.txt
@@ -124,7 +124,8 @@ symbol:
 * gpiochip_set_chained_irqchip(): sets up a chained irq handler for a
   gpio_chip from a parent IRQ and passes the struct gpio_chip* as handler
   data. (Notice handler data, since the irqchip data is likely used by the
-  parent irqchip!) This is for the chained type of chip.
+  parent irqchip!) This is for the chained type of chip. This is also used
+  to set up a nested irqchip if NULL is passed as handler.
 
 To use the helpers please keep the following in mind:
 
@@ -178,7 +179,8 @@ does not help since it pins the module to the kernel forever (it calls
 try_module_get()). A GPIO driver can use the following functions instead
 to request and free descriptors without being pinned to the kernel forever.
 
-	int gpiochip_request_own_desc(struct gpio_desc *desc, const char *label)
+	struct gpio_desc *gpiochip_request_own_desc(struct gpio_desc *desc,
+						    const char *label)
 
 	void gpiochip_free_own_desc(struct gpio_desc *desc)