[PATCH 1/5] gpiolib: introduce set_debounce method

[felipe.balbi@nokia.com]

From: Felipe Balbi <felipe.balbi@nokia.com>

Few architectures, like OMAP, allow you to set
a debouncing time for the gpio before generating
the IRQ. Teach gpiolib about that.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
---
 drivers/gpio/gpiolib.c     |   43 +++++++++++++++++++++++++++++++++++++++++++
 include/asm-generic/gpio.h |    5 +++++
 include/linux/gpio.h       |    5 +++++
 3 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index eb0c3fe..cd85fd1 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1447,6 +1447,49 @@ fail:
 }
 EXPORT_SYMBOL_GPL(gpio_direction_output);
 
+/**
+ * gpio_set_debounce - sets @debounce time for a @gpio
+ * @gpio: the gpio to set debounce time
+ * @debounce: debounce time is microseconds
+ */
+int gpio_set_debounce(unsigned gpio, unsigned debounce)
+{
+	unsigned long		flags;
+	struct gpio_chip	*chip;
+	struct gpio_desc	*desc = &gpio_desc[gpio];
+	int			status = -EINVAL;
+
+	spin_lock_irqsave(&gpio_lock, flags);
+
+	if (!gpio_is_valid(gpio))
+		goto fail;
+	chip = desc->chip;
+	if (!chip || !chip->set || !chip->set_debounce)
+		goto fail;
+	gpio -= chip->base;
+	if (gpio >= chip->ngpio)
+		goto fail;
+	status = gpio_ensure_requested(desc, gpio);
+	if (status < 0)
+		goto fail;
+
+	/* now we know the gpio is valid and chip won't vanish */
+
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	might_sleep_if(extra_checks && chip->can_sleep);
+
+	return chip->set_debounce(chip, gpio, debounce);
+
+fail:
+	spin_unlock_irqrestore(&gpio_lock, flags);
+	if (status)
+		pr_debug("%s: gpio-%d status %d\n",
+			__func__, gpio, status);
+
+	return status;
+}
+EXPORT_SYMBOL_GPL(gpio_set_debounce);
 
 /* I/O calls are only valid after configuration completed; the relevant
  * "is this a valid GPIO" error checks should already have been done.
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 979c6a5..ce3eb87 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -88,6 +88,9 @@ struct gpio_chip {
 						unsigned offset);
 	int			(*direction_output)(struct gpio_chip *chip,
 						unsigned offset, int value);
+	int			(*set_debounce)(struct gpio_chip *chip,
+						unsigned offset, unsigned debounce);
+
 	void			(*set)(struct gpio_chip *chip,
 						unsigned offset, int value);
 
@@ -121,6 +124,8 @@ extern void gpio_free(unsigned gpio);
 extern int gpio_direction_input(unsigned gpio);
 extern int gpio_direction_output(unsigned gpio, int value);
 
+extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
+
 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 4e949a5..03f616b 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -51,6 +51,11 @@ static inline int gpio_direction_output(unsigned gpio, int value)
 	return -ENOSYS;
 }
 
+static inline int gpio_set_debounce(unsigned gpio, unsigned debounce)
+{
+	return -ENOSYS;
+}
+
 static inline int gpio_get_value(unsigned gpio)
 {
 	/* GPIO can never have been requested or set as {in,out}put */
-- 
1.7.1