ASoC: codecs: msm8916-wcd-analog: get micbias voltage from dt

This patch adds bindings in DT to provide required micbias voltage which
could be specific to board. With this new binding, now the mic bias
voltage is left at hardware default value if the device tree does not
specify any mic bias voltage value. Correct micbias value is required
for mbhc buttons to work.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/qcom,msm8916-wcd-analog.txt

@@ -33,6 +33,7 @@ Required properties
  - vdd-micbias-supply: phandle of VDD_MICBIAS supply's regulator DT node.
 
 Optional Properties:
+- qcom,micbias-lvl:  Voltage (mV) for Mic Bias
 - qcom,micbias1-ext-cap: boolean, present if micbias1 has external capacitor
 			 connected.
 - qcom,micbias2-ext-cap: boolean, present if micbias2 has external capacitor

sound/soc/codecs/msm8916-wcd-analog.c

@@ -93,8 +93,12 @@
 #define MICB_1_EN_TX3_GND_SEL_TX_GND	0
 
 #define CDC_A_MICB_1_VAL		(0xf141)
+#define MICB_MIN_VAL 1600
+#define MICB_STEP_SIZE 50
+#define MICB_VOLTAGE_REGVAL(v)		((v - MICB_MIN_VAL)/MICB_STEP_SIZE)
 #define MICB_1_VAL_MICB_OUT_VAL_MASK	GENMASK(7, 3)
 #define MICB_1_VAL_MICB_OUT_VAL_V2P70V	((0x16)  << 3)
+#define MICB_1_VAL_MICB_OUT_VAL_V1P80V	((0x4)  << 3)
 #define CDC_A_MICB_1_CTL		(0xf142)
 
 #define MICB_1_CTL_CFILT_REF_SEL_MASK		BIT(1)
@@ -225,6 +229,7 @@ struct pm8916_wcd_analog_priv {
 	struct regulator_bulk_data supplies[ARRAY_SIZE(supply_names)];
 	unsigned int micbias1_cap_mode;
 	unsigned int micbias2_cap_mode;
+	unsigned int micbias_mv;
 };
 
 static const char *const adc2_mux_text[] = { "ZERO", "INP2", "INP3" };
@@ -265,18 +270,25 @@ static const struct snd_kcontrol_new pm8916_wcd_analog_snd_controls[] = {
 
 static void pm8916_wcd_analog_micbias_enable(struct snd_soc_codec *codec)
 {
+	struct pm8916_wcd_analog_priv *wcd = snd_soc_codec_get_drvdata(codec);
+
 	snd_soc_update_bits(codec, CDC_A_MICB_1_CTL,
 			    MICB_1_CTL_EXT_PRECHARG_EN_MASK |
 			    MICB_1_CTL_INT_PRECHARG_BYP_MASK,
 			    MICB_1_CTL_INT_PRECHARG_BYP_EXT_PRECHRG_SEL
 			    | MICB_1_CTL_EXT_PRECHARG_EN_ENABLE);
 
-	snd_soc_write(codec, CDC_A_MICB_1_VAL, MICB_1_VAL_MICB_OUT_VAL_V2P70V);
+	if (wcd->micbias_mv) {
+		snd_soc_write(codec, CDC_A_MICB_1_VAL,
+			      MICB_VOLTAGE_REGVAL(wcd->micbias_mv));
 		/*
 		 * Special headset needs MICBIAS as 2.7V so wait for
 		 * 50 msec for the MICBIAS to reach 2.7 volts.
 		 */
+		if (wcd->micbias_mv >= 2700)
 			msleep(50);
+	}
+
 	snd_soc_update_bits(codec, CDC_A_MICB_1_CTL,
 			    MICB_1_CTL_EXT_PRECHARG_EN_MASK |
 			    MICB_1_CTL_INT_PRECHARG_BYP_MASK, 0);
@@ -795,6 +807,9 @@ static int pm8916_wcd_analog_parse_dt(struct device *dev,
 	else
 		priv->micbias2_cap_mode = MICB_1_EN_NO_EXT_BYP_CAP;
 
+	of_property_read_u32(dev->of_node, "qcom,micbias-lvl",
+			     &priv->micbias_mv);
+
 	return 0;
 }