gpiolib: Implement gpio_to_irq() for wm831x

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

drivers/gpio/wm831x-gpio.c

@@ -22,6 +22,7 @@
 #include <linux/mfd/wm831x/core.h>
 #include <linux/mfd/wm831x/pdata.h>
 #include <linux/mfd/wm831x/gpio.h>
+#include <linux/mfd/wm831x/irq.h>
 
 struct wm831x_gpio {
 	struct wm831x *wm831x;
@@ -78,6 +79,17 @@ static void wm831x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 			value << offset);
 }
 
+static int wm831x_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	struct wm831x_gpio *wm831x_gpio = to_wm831x_gpio(chip);
+	struct wm831x *wm831x = wm831x_gpio->wm831x;
+
+	if (!wm831x->irq_base)
+		return -EINVAL;
+
+	return wm831x->irq_base + WM831X_IRQ_GPIO_1 + offset;
+}
+
 #ifdef CONFIG_DEBUG_FS
 static void wm831x_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 {
@@ -173,6 +185,7 @@ static struct gpio_chip template_chip = {
 	.get			= wm831x_gpio_get,
 	.direction_output	= wm831x_gpio_direction_out,
 	.set			= wm831x_gpio_set,
+	.to_irq			= wm831x_gpio_to_irq,
 	.dbg_show		= wm831x_gpio_dbg_show,
 	.can_sleep		= 1,
 };