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-rw-r--r--Documentation/gpio/consumer.txt27
1 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt
index 6ce544191ca6..c67f806401a5 100644
--- a/Documentation/gpio/consumer.txt
+++ b/Documentation/gpio/consumer.txt
@@ -199,6 +199,33 @@ The active-low state of a GPIO can also be queried using the following call:
Note that these functions should only be used with great moderation ; a driver
should not have to care about the physical line level.
+
+Set multiple GPIO outputs with a single function call
+-----------------------------------------------------
+The following functions set the output values of an array of GPIOs:
+
+ void gpiod_set_array(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array)
+ void gpiod_set_raw_array(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array)
+ void gpiod_set_array_cansleep(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array)
+ void gpiod_set_raw_array_cansleep(unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array)
+
+The array can be an arbitrary set of GPIOs. The functions will try to set
+GPIOs belonging to the same bank or chip simultaneously if supported by the
+corresponding chip driver. In that case a significantly improved performance
+can be expected. If simultaneous setting is not possible the GPIOs will be set
+sequentially.
+Note that for optimal performance GPIOs belonging to the same chip should be
+contiguous within the array of descriptors.
+
+
GPIOs mapped to IRQs
--------------------
GPIO lines can quite often be used as IRQs. You can get the IRQ number