gpiolib: request/free hooks
Add a new internal mechanism to gpiolib to support low power
operations by letting gpio_chip instances see when their GPIOs
are in use. When no GPIOs are active, chips may be able to
enter lower powered runtime states by disabling clocks and/or
power domains.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: "Magnus Damm" <magnus.damm@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 04cb1d1..81797ec 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -35,6 +35,10 @@
* @label: for diagnostics
* @dev: optional device providing the GPIOs
* @owner: helps prevent removal of modules exporting active GPIOs
+ * @request: optional hook for chip-specific activation, such as
+ * enabling module power and clock; may sleep
+ * @free: optional hook for chip-specific deactivation, such as
+ * disabling module power and clock; may sleep
* @direction_input: configures signal "offset" as input, or returns error
* @get: returns value for signal "offset"; for output signals this
* returns either the value actually sensed, or zero
@@ -67,6 +71,11 @@
struct device *dev;
struct module *owner;
+ int (*request)(struct gpio_chip *chip,
+ unsigned offset);
+ void (*free)(struct gpio_chip *chip,
+ unsigned offset);
+
int (*direction_input)(struct gpio_chip *chip,
unsigned offset);
int (*get)(struct gpio_chip *chip,
