ASoC: Allow configuration of WM8904 GPIO pin functions

Provide platform data allowing the configuration of the GPIO pins
on the WM8904 to be selected, allowing alternate functions to be
enabled.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/sound/soc/codecs/wm8904.c b/sound/soc/codecs/wm8904.c
index 593e47d..ce3f004 100644
--- a/sound/soc/codecs/wm8904.c
+++ b/sound/soc/codecs/wm8904.c
@@ -2425,6 +2425,7 @@
 static int wm8904_register(struct wm8904_priv *wm8904,
 			   enum snd_soc_control_type control)
 {
+	struct wm8904_pdata *pdata = wm8904->pdata;
 	int ret;
 	struct snd_soc_codec *codec = &wm8904->codec;
 	int i;
@@ -2530,6 +2531,17 @@
 		WM8904_LINEOUTRZC;
 	wm8904->reg_cache[WM8904_CLOCK_RATES_0] &= ~WM8904_SR_MODE;
 
+	/* Apply configuration from the platform data. */
+	if (wm8904->pdata) {
+		for (i = 0; i < WM8904_GPIO_REGS; i++) {
+			if (!pdata->gpio_cfg[i])
+				continue;
+
+			wm8904->reg_cache[WM8904_GPIO_CONTROL_1 + i]
+				= pdata->gpio_cfg[i] & 0xffff;
+		}
+	}
+
 	/* Set Class W by default - this will be managed by the Class
 	 * G widget at runtime where bypass paths are available.
 	 */