[PATCH v2 3/3] ASoC: codec: tlv3204: Moving GPIO reset and add ADC reset

[Michael Sit Wei Hong]

Moving GPIO reset to a later stage and before clock registration to
ensure that the host system and codec clocks are in sync. If the host
register clock values prior to gpio reset, the last configured codec clock
is registered to the host. The codec then gets gpio resetted setting the
codec clocks to their default value, causing a mismatch. Host system will
skip clock setting thinking the codec clocks are already at the requested
rate.

ADC reset is added to ensure the next audio capture does not have
undesired artifacts. It is probably related to the original code
where the probe function resets the ADC prior to 1st record.

Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit at intel.com>
Reviewed-by: Sia Jee Heng <jee.heng.sia at intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 sound/soc/codecs/tlv320aic32x4.c | 47 ++++++++++++++++++++++++--------
 1 file changed, 35 insertions(+), 12 deletions(-)

diff --git a/sound/soc/codecs/tlv320aic32x4.c b/sound/soc/codecs/tlv320aic32x4.c
index 6c2338ea5d8d..8dcea566b375 100644
--- a/sound/soc/codecs/tlv320aic32x4.c
+++ b/sound/soc/codecs/tlv320aic32x4.c
@@ -50,6 +50,28 @@ struct aic32x4_priv {
 	struct device *dev;
 };
 
+static int aic32x4_reset_adc(struct snd_soc_dapm_widget *w,
+			     struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
+	u32 adc_reg;
+
+	/*
+	 * Workaround: the datasheet does not mention a required programming
+	 * sequence but experiments show the ADC needs to be reset after each
+	 * capture to avoid audible artifacts.
+	 */
+	switch (event) {
+	case SND_SOC_DAPM_POST_PMD:
+		adc_reg = snd_soc_component_read(component, AIC32X4_ADCSETUP);
+		snd_soc_component_write(component, AIC32X4_ADCSETUP, adc_reg |
+					AIC32X4_LADC_EN | AIC32X4_RADC_EN);
+		snd_soc_component_write(component, AIC32X4_ADCSETUP, adc_reg);
+		break;
+	}
+	return 0;
+};
+
 static int mic_bias_event(struct snd_soc_dapm_widget *w,
 	struct snd_kcontrol *kcontrol, int event)
 {
@@ -434,6 +456,7 @@ static const struct snd_soc_dapm_widget aic32x4_dapm_widgets[] = {
 	SND_SOC_DAPM_SUPPLY("Mic Bias", AIC32X4_MICBIAS, 6, 0, mic_bias_event,
 			SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_PRE_PMD),
 
+	SND_SOC_DAPM_POST("ADC Reset", aic32x4_reset_adc),
 
 	SND_SOC_DAPM_OUTPUT("HPL"),
 	SND_SOC_DAPM_OUTPUT("HPR"),
@@ -665,8 +688,8 @@ static int aic32x4_set_processing_blocks(struct snd_soc_component *component,
 }
 
 static int aic32x4_setup_clocks(struct snd_soc_component *component,
-			unsigned int sample_rate, unsigned int channel,
-			unsigned int bit_depth)
+				unsigned int sample_rate, unsigned int channel,
+				unsigned int bit_depth)
 {
 	u8 aosr;
 	u16 dosr;
@@ -958,12 +981,6 @@ static int aic32x4_component_probe(struct snd_soc_component *component)
 	if (ret)
 		return ret;
 
-	if (gpio_is_valid(aic32x4->rstn_gpio)) {
-		ndelay(10);
-		gpio_set_value(aic32x4->rstn_gpio, 1);
-		mdelay(1);
-	}
-
 	snd_soc_component_write(component, AIC32X4_RESET, 0x01);
 
 	if (aic32x4->setup)
@@ -1196,10 +1213,6 @@ int aic32x4_probe(struct device *dev, struct regmap *regmap)
 		aic32x4->mclk_name = "mclk";
 	}
 
-	ret = aic32x4_register_clocks(dev, aic32x4->mclk_name);
-	if (ret)
-		return ret;
-
 	if (gpio_is_valid(aic32x4->rstn_gpio)) {
 		ret = devm_gpio_request_one(dev, aic32x4->rstn_gpio,
 				GPIOF_OUT_INIT_LOW, "tlv320aic32x4 rstn");
@@ -1221,6 +1234,16 @@ int aic32x4_probe(struct device *dev, struct regmap *regmap)
 		return ret;
 	}
 
+	if (gpio_is_valid(aic32x4->rstn_gpio)) {
+		ndelay(10);
+		gpio_set_value_cansleep(aic32x4->rstn_gpio, 1);
+		mdelay(1);
+	}
+
+	ret = aic32x4_register_clocks(dev, aic32x4->mclk_name);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 EXPORT_SYMBOL(aic32x4_probe);
-- 
2.17.1