ASoC: tlv320aic32x4: Add rstn gpio to platform data.

Add the possibility to specify a gpio through platform data
so that a HW reset can be issued to the codec.

Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/tlv320aic32x4.c b/sound/soc/codecs/tlv320aic32x4.c
index d7d0e18..e39e08d 100644
--- a/sound/soc/codecs/tlv320aic32x4.c
+++ b/sound/soc/codecs/tlv320aic32x4.c
@@ -28,6 +28,7 @@
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/pm.h>
+#include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/cdev.h>
 #include <linux/slab.h>
@@ -65,6 +66,7 @@
 	u32 power_cfg;
 	u32 micpga_routing;
 	bool swapdacs;
+	int rstn_gpio;
 };
 
 /* 0dB min, 1dB steps */
@@ -627,10 +629,20 @@
 {
 	struct aic32x4_priv *aic32x4 = snd_soc_codec_get_drvdata(codec);
 	u32 tmp_reg;
+	int ret;
 
 	codec->hw_write = (hw_write_t) i2c_master_send;
 	codec->control_data = aic32x4->control_data;
 
+	if (aic32x4->rstn_gpio >= 0) {
+		ret = devm_gpio_request_one(codec->dev, aic32x4->rstn_gpio,
+				GPIOF_OUT_INIT_LOW, "tlv320aic32x4 rstn");
+		if (ret != 0)
+			return ret;
+		ndelay(10);
+		gpio_set_value(aic32x4->rstn_gpio, 1);
+	}
+
 	snd_soc_write(codec, AIC32X4_RESET, 0x01);
 
 	/* Power platform configuration */
@@ -723,10 +735,12 @@
 		aic32x4->power_cfg = pdata->power_cfg;
 		aic32x4->swapdacs = pdata->swapdacs;
 		aic32x4->micpga_routing = pdata->micpga_routing;
+		aic32x4->rstn_gpio = pdata->rstn_gpio;
 	} else {
 		aic32x4->power_cfg = 0;
 		aic32x4->swapdacs = false;
 		aic32x4->micpga_routing = 0;
+		aic32x4->rstn_gpio = -1;
 	}
 
 	ret = snd_soc_register_codec(&i2c->dev,