[DRIVER][SOUND] wm8983: Add mute control functionality

sound/soc/codecs/wm8983.c

@@ -16,6 +16,7 @@
 #include <linux/regmap.h>
 #include <linux/spi/spi.h>
 #include <linux/slab.h>
+#include <linux/gpio/consumer.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -96,9 +97,11 @@ static const int vol_update_regs[] = {
 };
 
 struct wm8983_priv {
+	struct clk *mclk;
 	struct regmap *regmap;
 	u32 sysclk;
 	u32 bclk;
+	struct gpio_desc *mute;
 };
 
 static const struct {
@@ -567,6 +570,10 @@ static bool wm8983_writeable(struct device *dev, unsigned int reg)
 static int wm8983_dac_mute(struct snd_soc_dai *dai, int mute, int direction)
 {
 	struct snd_soc_component *component = dai->component;
+	struct wm8983_priv *wm8983 = snd_soc_component_get_drvdata(component);
+
+	if (wm8983->mute)
+		gpiod_set_value_cansleep(wm8983->mute, mute);
 
 	return snd_soc_component_update_bits(component, WM8983_DAC_CONTROL,
 				   WM8983_SOFTMUTE_MASK,
@@ -833,6 +840,9 @@ static int wm8983_startup(struct snd_pcm_substream *substream,
 	struct snd_soc_component *component = dai->component;
 	struct wm8983_priv *wm8983 = snd_soc_component_get_drvdata(component);
 
+	if (wm8983->mute)
+		gpiod_set_value_cansleep(wm8983->mute, 1);
+
 	return 0;
 }
 
@@ -841,6 +851,9 @@ static void wm8983_shutdown(struct snd_pcm_substream *substream,
 {
 	struct snd_soc_component *component = dai->component;
 	struct wm8983_priv *wm8983 = snd_soc_component_get_drvdata(component);
+
+	if (wm8983->mute)
+		gpiod_set_value_cansleep(wm8983->mute, 0);
 }
 
 static int wm8983_set_sysclk(struct snd_soc_dai *dai,
@@ -1044,6 +1057,12 @@ static int wm8983_i2c_probe(struct i2c_client *i2c,
 		return ret;
 	}
 
+	wm8983->mute = devm_gpiod_get(&i2c->dev, "mute", GPIOD_OUT_LOW);
+	if (IS_ERR(wm8983->mute)) {
+		dev_err(&i2c->dev, "Failed to get mute line: %ld\n", PTR_ERR(wm8983->mute));
+		wm8983->mute = NULL;
+	}
+
 	i2c_set_clientdata(i2c, wm8983);
 
 	ret = devm_snd_soc_register_component(&i2c->dev,