ASoC: tas2764: Add SDZ regulator

Multiple amps can be connected to the same SDZ GPIO. Using raw GPIOs for
this breaks, as there is no concept of refcounting/sharing. In order to
model these platforms, introduce support for an SDZ "regulator". This
allows us to represent the SDZ GPIO as a simple regulator-fixed, and
then the regulator core takes care of refcounting so that all codecs are
only powered down once all the driver instances are in the suspend
state.

Signed-off-by: Hector Martin <marcan@marcan.st>

Author: marcan

sound/soc/codecs/tas2764.c

@@ -34,6 +34,7 @@ struct tas2764_priv {
 	struct snd_soc_component *component;
 	struct gpio_desc *reset_gpio;
 	struct gpio_desc *sdz_gpio;
+	struct regulator *sdz_reg;
 	struct regmap *regmap;
 	struct device *dev;
 	int irq;
@@ -157,6 +158,8 @@ static int tas2764_codec_suspend(struct snd_soc_component *component)
 	if (tas2764->sdz_gpio)
 		gpiod_set_value_cansleep(tas2764->sdz_gpio, 0);
 
+	regulator_disable(tas2764->sdz_reg);
+
 	regcache_cache_only(tas2764->regmap, true);
 	regcache_mark_dirty(tas2764->regmap);
 
@@ -168,19 +171,26 @@ static int tas2764_codec_resume(struct snd_soc_component *component)
 	struct tas2764_priv *tas2764 = snd_soc_component_get_drvdata(component);
 	int ret;
 
+	ret = regulator_enable(tas2764->sdz_reg);
+
+	if (ret) {
+		dev_err(tas2764->dev, "Failed to enable regulator\n");
+		return ret;
+	}
+
 	if (tas2764->sdz_gpio) {
 		gpiod_set_value_cansleep(tas2764->sdz_gpio, 1);
-		usleep_range(1000, 2000);
 	}
 
-	ret = tas2764_update_pwr_ctrl(tas2764);
+	usleep_range(1000, 2000);
 
+	regcache_cache_only(tas2764->regmap, false);
+
+	ret = regcache_sync(tas2764->regmap);
 	if (ret < 0)
 		return ret;
 
-	regcache_cache_only(tas2764->regmap, false);
-
-	return regcache_sync(tas2764->regmap);
+	return tas2764_update_pwr_ctrl(tas2764);
 }
 #else
 #define tas2764_codec_suspend NULL
@@ -213,7 +223,7 @@ static const struct snd_soc_dapm_widget tas2764_dapm_widgets[] = {
 	SND_SOC_DAPM_DAC("DAC", NULL, SND_SOC_NOPM, 0, 0),
 	SND_SOC_DAPM_OUTPUT("OUT"),
 	SND_SOC_DAPM_SIGGEN("VMON"),
-	SND_SOC_DAPM_SIGGEN("IMON")
+	SND_SOC_DAPM_SIGGEN("IMON"),
 };
 
 static const struct snd_soc_dapm_route tas2764_audio_map[] = {
@@ -640,11 +650,18 @@ static int tas2764_codec_probe(struct snd_soc_component *component)
 
 	tas2764->component = component;
 
+	ret = regulator_enable(tas2764->sdz_reg);
+	if (ret != 0) {
+		dev_err(tas2764->dev, "Failed to enable regulator: %d\n", ret);
+		return ret;
+	}
+
 	if (tas2764->sdz_gpio) {
 		gpiod_set_value_cansleep(tas2764->sdz_gpio, 1);
-		usleep_range(1000, 2000);
 	}
 
+	usleep_range(1000, 2000);
+
 	tas2764_reset(tas2764);
 	regmap_reinit_cache(tas2764->regmap, &tas2764_i2c_regmap);
 
@@ -716,6 +733,9 @@ static int tas2764_codec_probe(struct snd_soc_component *component)
 
 static void tas2764_codec_remove(struct snd_soc_component *component)
 {
+	struct tas2764_priv *tas2764 = snd_soc_component_get_drvdata(component);
+
+	regulator_disable(tas2764->sdz_reg);
 	sysfs_remove_groups(&component->dev->kobj, tas2764_sysfs_groups);
 }
 
@@ -818,6 +838,11 @@ static int tas2764_parse_dt(struct device *dev, struct tas2764_priv *tas2764)
 {
 	int ret = 0;
 
+	tas2764->sdz_reg = devm_regulator_get(dev, "SDZ");
+	if (IS_ERR(tas2764->sdz_reg))
+		return dev_err_probe(dev, PTR_ERR(tas2764->sdz_reg),
+				"Failed to get SDZ supply\n");
+
 	tas2764->reset_gpio = devm_gpiod_get_optional(tas2764->dev, "reset",
 						      GPIOD_OUT_HIGH);
 	if (IS_ERR(tas2764->reset_gpio)) {