[PATCH] gpiolib: Add gpio_detect, gpio_debounce and gpio_alt_func features to GPIOLIB

[Alek Du]

Add some more functions to GPIOLIB, they are:
* gpio_detect is to set GPIO interrupt triggering method (edge, level, high,
  low, etc.)
* gpio_debounce is to set GPIO trigger HW debounce value if GPIO hw supports.
* gpio_alt_func is to set pin as alternative function or GPIO.

We will submit GPIO drivers that leverage this new interface later.

Signed-off-by: Alek Du <alek.du@xxxxxxxxx>
---
 drivers/gpio/gpiolib.c     |   33 +++++++++++++++++++++++++++++++++
 include/asm-generic/gpio.h |   25 ++++++++++++++++++++++++-
 include/linux/gpio.h       |   15 +++++++++++++++
 3 files changed, 72 insertions(+), 1 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 51a8d41..087efce 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1066,6 +1066,39 @@ void __gpio_set_value(unsigned gpio, int value)
 }
 EXPORT_SYMBOL_GPL(__gpio_set_value);
 
+void gpio_detect(unsigned gpio, enum gpio_trigger_t value)
+{
+	struct gpio_chip	*chip;
+
+	chip = gpio_to_chip(gpio);
+	WARN_ON(extra_checks && chip->can_sleep);
+	if (chip->detect)
+		chip->detect(chip, gpio - chip->base, value);
+}
+EXPORT_SYMBOL_GPL(gpio_detect);
+
+void gpio_debounce(unsigned gpio, int value)
+{
+	struct gpio_chip	*chip;
+
+	chip = gpio_to_chip(gpio);
+	WARN_ON(extra_checks && chip->can_sleep);
+	if (chip->debounce)
+		chip->debounce(chip, gpio - chip->base, value);
+}
+EXPORT_SYMBOL_GPL(gpio_debounce);
+
+void gpio_alt_func(unsigned gpio, int value)
+{
+	struct gpio_chip	*chip;
+
+	chip = gpio_to_chip(gpio);
+	WARN_ON(extra_checks && chip->can_sleep);
+	if (chip->alt_func)
+		chip->alt_func(chip, gpio - chip->base, value);
+}
+EXPORT_SYMBOL_GPL(gpio_alt_func);
+
 /**
  * __gpio_cansleep() - report whether gpio value access will sleep
  * @gpio: gpio in question
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index d6c379d..de9aaf9 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -30,6 +30,15 @@ static inline int gpio_is_valid(int number)
 struct seq_file;
 struct module;
 
+enum gpio_trigger_t {
+	DETECT_LEVEL_LOW = -2,
+	DETECT_EDGE_FALLING = -1,
+	DETECT_DISABLE = 0,
+	DETECT_EDGE_RISING = 1,
+	DETECT_LEVEL_HIGH = 2,
+	DETECT_EDGE_BOTH = 3,
+};
+
 /**
  * struct gpio_chip - abstract a GPIO controller
  * @label: for diagnostics
@@ -44,6 +53,9 @@ struct module;
  *	returns either the value actually sensed, or zero
  * @direction_output: configures signal "offset" as output, or returns error
  * @set: assigns output value for signal "offset"
+ * @detect: configures signal interrupt detection method, see gpio_trigger_t
+ * @debounce: configures signal interrupt detection debounce
+ * @alt_func: configure signal as GPIO or alternative function
  * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
  *	implementation may not sleep
  * @dbg_show: optional routine to show contents in debugfs; default code
@@ -89,6 +101,15 @@ struct gpio_chip {
 	void			(*set)(struct gpio_chip *chip,
 						unsigned offset, int value);
 
+	void			(*detect)(struct gpio_chip *chip,
+						unsigned offset,
+						enum gpio_trigger_t value);
+	void			(*debounce)(struct gpio_chip *chip,
+						unsigned offset,
+						int value);
+	void			(*alt_func)(struct gpio_chip *chip,
+						unsigned offset, int value);
+
 	int			(*to_irq)(struct gpio_chip *chip,
 						unsigned offset);
 
@@ -118,7 +139,9 @@ extern void gpio_free(unsigned gpio);
 
 extern int gpio_direction_input(unsigned gpio);
 extern int gpio_direction_output(unsigned gpio, int value);
-
+extern void gpio_detect(unsigned gpio, enum gpio_trigger_t value);
+extern void gpio_debounce(unsigned gpio, int value);
+extern void gpio_alt_func(unsigned gpio, int value);
 extern int gpio_get_value_cansleep(unsigned gpio);
 extern void gpio_set_value_cansleep(unsigned gpio, int value);
 
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index e10c49a..76dd5f9 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -82,6 +82,21 @@ static inline void gpio_set_value_cansleep(unsigned gpio, int value)
 	WARN_ON(1);
 }
 
+static inline void gpio_detect(unsigned gpio, int value)
+{
+	WARN_ON(1);
+}
+
+static inline void gpio_debounce(unsigned gpio, int value)
+{
+	WARN_ON(1);
+}
+
+static inline void gpio_alt_func(unsigned gpio, int value)
+{
+	WARN_ON(1);
+}
+
 static inline int gpio_export(unsigned gpio, bool direction_may_change)
 {
 	/* GPIO can never have been requested or set as {in,out}put */
-- 
1.6.0.4
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