ASoC: tlv320aic31xx: configure output common-mode voltage

The tlv320aic31xx devices allow to adjust the output common-mode voltage
for best analog performance. The datasheet states that the common mode
voltage should be set to be <= AVDD/2.

This changes allows to configure the output common-mode voltage via a DT
property. If the property is absent the voltage is automatically chosen
as the highest voltage below/equal to AVDD/2.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Link: https://lore.kernel.org/r/20191118151207.28576-1-l.stach@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/tlv320aic31xx.txt

@@ -29,6 +29,11 @@ Optional properties:
         3 or MICBIAS_AVDD - MICBIAS output is connected to AVDD
 	If this node is not mentioned or if the value is unknown, then
 	micbias	is set to 2.0V.
+- ai31xx-ocmv - output common-mode voltage setting
+        0 - 1.35V,
+        1 - 1.5V,
+        2 - 1.65V,
+        3 - 1.8V
 
 Deprecated properties:
 

sound/soc/codecs/tlv320aic31xx.c

@@ -171,6 +171,7 @@ struct aic31xx_priv {
 	int rate_div_line;
 	bool master_dapm_route_applied;
 	int irq;
+	u8 ocmv; /* output common-mode voltage */
 };
 
 struct aic31xx_rate_divs {
@@ -1312,6 +1313,11 @@ static int aic31xx_codec_probe(struct snd_soc_component *component)
 	if (ret)
 		return ret;
 
+	/* set output common-mode voltage */
+	snd_soc_component_update_bits(component, AIC31XX_HPDRIVER,
+				      AIC31XX_HPD_OCMV_MASK,
+				      aic31xx->ocmv << AIC31XX_HPD_OCMV_SHIFT);
+
 	return 0;
 }
 
@@ -1501,6 +1507,43 @@ static irqreturn_t aic31xx_irq(int irq, void *data)
 		return IRQ_NONE;
 }
 
+static void aic31xx_configure_ocmv(struct aic31xx_priv *priv)
+{
+	struct device *dev = priv->dev;
+	int dvdd, avdd;
+	u32 value;
+
+	if (dev->fwnode &&
+	    fwnode_property_read_u32(dev->fwnode, "ai31xx-ocmv", &value)) {
+		/* OCMV setting is forced by DT */
+		if (value <= 3) {
+			priv->ocmv = value;
+			return;
+		}
+	}
+
+	avdd = regulator_get_voltage(priv->supplies[3].consumer);
+	dvdd = regulator_get_voltage(priv->supplies[5].consumer);
+
+	if (avdd > 3600000 || dvdd > 1950000) {
+		dev_warn(dev,
+			 "Too high supply voltage(s) AVDD: %d, DVDD: %d\n",
+			 avdd, dvdd);
+	} else if (avdd == 3600000 && dvdd == 1950000) {
+		priv->ocmv = AIC31XX_HPD_OCMV_1_8V;
+	} else if (avdd >= 3300000 && dvdd >= 1800000) {
+		priv->ocmv = AIC31XX_HPD_OCMV_1_65V;
+	} else if (avdd >= 3000000 && dvdd >= 1650000) {
+		priv->ocmv = AIC31XX_HPD_OCMV_1_5V;
+	} else if (avdd >= 2700000 && dvdd >= 1525000) {
+		priv->ocmv = AIC31XX_HPD_OCMV_1_35V;
+	} else {
+		dev_warn(dev,
+			 "Invalid supply voltage(s) AVDD: %d, DVDD: %d\n",
+			 avdd, dvdd);
+	}
+}
+
 static int aic31xx_i2c_probe(struct i2c_client *i2c,
 			     const struct i2c_device_id *id)
 {
@@ -1570,6 +1613,8 @@ static int aic31xx_i2c_probe(struct i2c_client *i2c,
 		return ret;
 	}
 
+	aic31xx_configure_ocmv(aic31xx);
+
 	if (aic31xx->irq > 0) {
 		regmap_update_bits(aic31xx->regmap, AIC31XX_GPIO1,
 				   AIC31XX_GPIO1_FUNC_MASK,

sound/soc/codecs/tlv320aic31xx.h

@@ -232,6 +232,14 @@ struct aic31xx_pdata {
 #define AIC31XX_HSD_HP			0x01
 #define AIC31XX_HSD_HS			0x03
 
+/* AIC31XX_HPDRIVER */
+#define AIC31XX_HPD_OCMV_MASK		GENMASK(4, 3)
+#define AIC31XX_HPD_OCMV_SHIFT		3
+#define AIC31XX_HPD_OCMV_1_35V		0x0
+#define AIC31XX_HPD_OCMV_1_5V		0x1
+#define AIC31XX_HPD_OCMV_1_65V		0x2
+#define AIC31XX_HPD_OCMV_1_8V		0x3
+
 /* AIC31XX_MICBIAS */
 #define AIC31XX_MICBIAS_MASK		GENMASK(1, 0)
 #define AIC31XX_MICBIAS_SHIFT		0