gpiolib: Implement set_debounce for WM831x GPIOs

The debounce times are approximate, they can be selected using the two
input functions.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/gpio/wm831x-gpio.c b/drivers/gpio/wm831x-gpio.c
index 1fa449a1a4cb..309644cf4d9b 100644
--- a/drivers/gpio/wm831x-gpio.c
+++ b/drivers/gpio/wm831x-gpio.c
@@ -108,6 +108,37 @@ static int wm831x_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
         return wm831x->irq_base + WM831X_IRQ_GPIO_1 + offset;
 }
 
+static int wm831x_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
+                                    unsigned debounce)
+{
+        struct wm831x_gpio *wm831x_gpio = to_wm831x_gpio(chip);
+        struct wm831x *wm831x = wm831x_gpio->wm831x;
+        int reg = WM831X_GPIO1_CONTROL + offset;
+        int ret, fn;
+
+        ret = wm831x_reg_read(wm831x, reg);
+        if (ret < 0)
+                return ret;
+
+        switch (ret & WM831X_GPN_FN_MASK) {
+        case 0:
+        case 1:
+                break;
+        default:
+                /* Not in GPIO mode */
+                return -EBUSY;
+        }
+
+        if (debounce >= 32 && debounce <= 64)
+                fn = 0;
+        else if (debounce >= 4000 && debounce <= 8000)
+                fn = 1;
+        else
+                return -EINVAL;
+
+        return wm831x_set_bits(wm831x, reg, WM831X_GPN_FN_MASK, fn);
+}
+
 #ifdef CONFIG_DEBUG_FS
 static void wm831x_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 {
@@ -208,6 +239,7 @@ static struct gpio_chip template_chip = {
         .direction_output       = wm831x_gpio_direction_out,
         .set                    = wm831x_gpio_set,
         .to_irq                 = wm831x_gpio_to_irq,
+        .set_debounce           = wm831x_gpio_set_debounce,
         .dbg_show               = wm831x_gpio_dbg_show,
         .can_sleep              = 1,
 };