bcma: add gpio_to_irq

The old bcm47xx gpio code had support for gpio_to_irq, but the new
code did not provide this function, but returned -ENXIO all the time.
This patch adds the missing function.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/bcma/driver_gpio.c b/drivers/bcma/driver_gpio.c
index 9a6f585..0b5df53 100644
--- a/drivers/bcma/driver_gpio.c
+++ b/drivers/bcma/driver_gpio.c
@@ -73,6 +73,16 @@
 	bcma_chipco_gpio_pullup(cc, 1 << gpio, 0);
 }
 
+static int bcma_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
+{
+	struct bcma_drv_cc *cc = bcma_gpio_get_cc(chip);
+
+	if (cc->core->bus->hosttype == BCMA_HOSTTYPE_SOC)
+		return bcma_core_irq(cc->core);
+	else
+		return -EINVAL;
+}
+
 int bcma_gpio_init(struct bcma_drv_cc *cc)
 {
 	struct gpio_chip *chip = &cc->gpio;
@@ -85,6 +95,7 @@
 	chip->set		= bcma_gpio_set_value;
 	chip->direction_input	= bcma_gpio_direction_input;
 	chip->direction_output	= bcma_gpio_direction_output;
+	chip->to_irq		= bcma_gpio_to_irq;
 	chip->ngpio		= 16;
 	/* There is just one SoC in one device and its GPIO addresses should be
 	 * deterministic to address them more easily. The other buses could get