ASoC: tas2770: 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.

This also reworks the sleep/resume logic to copy what tas2764 does,
which makes more sense.

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

Author: marcan

sound/soc/codecs/tas2770.c

@@ -73,23 +73,21 @@ static int tas2770_codec_suspend(struct snd_soc_component *component)
 	struct tas2770_priv *tas2770 = snd_soc_component_get_drvdata(component);
 	int ret = 0;
 
-	regcache_cache_only(tas2770->regmap, true);
-	regcache_mark_dirty(tas2770->regmap);
+	ret = snd_soc_component_update_bits(component, TAS2770_PWR_CTRL,
+					    TAS2770_PWR_CTRL_MASK,
+					    TAS2770_PWR_CTRL_SHUTDOWN);
+	if (ret < 0)
+		return ret;
 
-	if (tas2770->sdz_gpio) {
+	if (tas2770->sdz_gpio)
 		gpiod_set_value_cansleep(tas2770->sdz_gpio, 0);
-	} else {
-		ret = snd_soc_component_update_bits(component, TAS2770_PWR_CTRL,
-						    TAS2770_PWR_CTRL_MASK,
-						    TAS2770_PWR_CTRL_SHUTDOWN);
-		if (ret < 0) {
-			regcache_cache_only(tas2770->regmap, false);
-			regcache_sync(tas2770->regmap);
-			return ret;
-		}
 
-		ret = 0;
-	}
+	regulator_disable(tas2770->sdz_reg);
+
+	regcache_cache_only(tas2770->regmap, true);
+	regcache_mark_dirty(tas2770->regmap);
+
+	usleep_range(6000, 7000);
 
 	return ret;
 }
@@ -99,18 +97,26 @@ static int tas2770_codec_resume(struct snd_soc_component *component)
 	struct tas2770_priv *tas2770 = snd_soc_component_get_drvdata(component);
 	int ret;
 
-	if (tas2770->sdz_gpio) {
-		gpiod_set_value_cansleep(tas2770->sdz_gpio, 1);
-		usleep_range(1000, 2000);
-	} else {
-		ret = tas2770_update_pwr_ctrl(tas2770);
-		if (ret < 0)
-			return ret;
+	ret = regulator_enable(tas2770->sdz_reg);
+
+	if (ret) {
+		dev_err(tas2770->dev, "Failed to enable regulator\n");
+		return ret;
 	}
 
+	if (tas2770->sdz_gpio)
+		gpiod_set_value_cansleep(tas2770->sdz_gpio, 1);
+
+
+	usleep_range(1000, 2000);
+
 	regcache_cache_only(tas2770->regmap, false);
 
-	return regcache_sync(tas2770->regmap);
+	ret = regcache_sync(tas2770->regmap);
+	if (ret < 0)
+		return ret;
+
+	return tas2770_update_pwr_ctrl(tas2770);
 }
 #else
 #define tas2770_codec_suspend NULL
@@ -545,6 +551,12 @@ static int tas2770_codec_probe(struct snd_soc_component *component)
 
 	tas2770->component = component;
 
+	ret = regulator_enable(tas2770->sdz_reg);
+	if (ret != 0) {
+		dev_err(tas2770->dev, "Failed to enable regulator: %d\n", ret);
+		return ret;
+	}
+
 	if (tas2770->sdz_gpio) {
 		gpiod_set_value_cansleep(tas2770->sdz_gpio, 1);
 		usleep_range(1000, 2000);
@@ -569,6 +581,13 @@ static int tas2770_codec_probe(struct snd_soc_component *component)
 	return 0;
 }
 
+static void tas2770_codec_remove(struct snd_soc_component *component)
+{
+	struct tas2770_priv *tas2770 = snd_soc_component_get_drvdata(component);
+
+	regulator_disable(tas2770->sdz_reg);
+}
+
 static DECLARE_TLV_DB_SCALE(tas2770_digital_tlv, 1100, 50, 0);
 static DECLARE_TLV_DB_SCALE(tas2770_playback_volume, -12750, 50, 0);
 
@@ -581,6 +600,7 @@ static const struct snd_kcontrol_new tas2770_snd_controls[] = {
 
 static const struct snd_soc_component_driver soc_component_driver_tas2770 = {
 	.probe			= tas2770_codec_probe,
+	.remove			= tas2770_codec_remove,
 	.suspend		= tas2770_codec_suspend,
 	.resume			= tas2770_codec_resume,
 	.controls		= tas2770_snd_controls,
@@ -705,6 +725,11 @@ static int tas2770_parse_dt(struct device *dev, struct tas2770_priv *tas2770)
 		tas2770->v_sense_slot = -1;
 	}
 
+	tas2770->sdz_reg = devm_regulator_get(dev, "SDZ");
+	if (IS_ERR(tas2770->sdz_reg))
+		return dev_err_probe(dev, PTR_ERR(tas2770->sdz_reg),
+				     "Failed to get SDZ supply\n");
+
 	tas2770->sdz_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
 	if (IS_ERR(tas2770->sdz_gpio)) {
 		if (PTR_ERR(tas2770->sdz_gpio) == -EPROBE_DEFER)

sound/soc/codecs/tas2770.h

@@ -134,6 +134,7 @@ struct tas2770_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 v_sense_slot;