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From:   Srinivasa Rao Mandadapu <srivasam@codeaurora.org>
To:     agross@kernel.org, bjorn.andersson@linaro.org, lgirdwood@gmail.com,
        broonie@kernel.org, robh+dt@kernel.org, plai@codeaurora.org,
        bgoswami@codeaurora.org, perex@perex.cz, tiwai@suse.com,
        srinivas.kandagatla@linaro.org, rohitkr@codeaurora.org,
        linux-arm-msm@vger.kernel.org, alsa-devel@alsa-project.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        swboyd@chromium.org, judyhsiao@chromium.org
Cc:     Srinivasa Rao Mandadapu <srivasam@codeaurora.org>
Subject: [PATCH] ASoC: qcom: lpass-cpu: Fix pop noise during audio capture begin
Date:   Thu, 13 May 2021 17:15:39 +0530
Message-Id: <20210513114539.4813-1-srivasam@codeaurora.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

This patch fixes PoP noise of around 15ms observed during audio capture begin.
Enables BCLK and LRCLK in snd_soc_dai_ops startup call for introducing some delay
before capture start and clock enable.

Signed-off-by: Judy Hsiao <judyhsiao@chromium.org>
Signed-off-by: Srinivasa Rao Mandadapu <srivasam@codeaurora.org>
---
 sound/soc/qcom/lpass-cpu.c | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/sound/soc/qcom/lpass-cpu.c b/sound/soc/qcom/lpass-cpu.c
index c62d2612e8f5..3dcfc2f115a7 100644
--- a/sound/soc/qcom/lpass-cpu.c
+++ b/sound/soc/qcom/lpass-cpu.c
@@ -73,14 +73,28 @@ static int lpass_cpu_daiops_startup(struct snd_pcm_substream *substream,
 		struct snd_soc_dai *dai)
 {
 	struct lpass_data *drvdata = snd_soc_dai_get_drvdata(dai);
-	int ret;
+	struct lpaif_i2sctl *i2sctl = drvdata->i2sctl;
+	unsigned int id = dai->driver->id;
+	int ret = -EINVAL;
 
 	ret = clk_prepare_enable(drvdata->mi2s_osr_clk[dai->driver->id]);
 	if (ret) {
 		dev_err(dai->dev, "error in enabling mi2s osr clk: %d\n", ret);
 		return ret;
 	}
-	ret = clk_prepare(drvdata->mi2s_bit_clk[dai->driver->id]);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		ret = regmap_fields_write(i2sctl->spken, id,
+						 LPAIF_I2SCTL_SPKEN_ENABLE);
+	} else  {
+		ret = regmap_fields_write(i2sctl->micen, id,
+						 LPAIF_I2SCTL_MICEN_ENABLE);
+	}
+	if (ret)
+		dev_err(dai->dev, "error writing to i2sctl reg: %d\n",
+			ret);
+
+	ret = clk_prepare_enable(drvdata->mi2s_bit_clk[dai->driver->id]);
 	if (ret) {
 		dev_err(dai->dev, "error in enabling mi2s bit clk: %d\n", ret);
 		clk_disable_unprepare(drvdata->mi2s_osr_clk[dai->driver->id]);
@@ -93,9 +107,23 @@ static void lpass_cpu_daiops_shutdown(struct snd_pcm_substream *substream,
 		struct snd_soc_dai *dai)
 {
 	struct lpass_data *drvdata = snd_soc_dai_get_drvdata(dai);
+	struct lpaif_i2sctl *i2sctl = drvdata->i2sctl;
+	unsigned int id = dai->driver->id;
+	int ret = -EINVAL;
 
 	clk_disable_unprepare(drvdata->mi2s_osr_clk[dai->driver->id]);
-	clk_unprepare(drvdata->mi2s_bit_clk[dai->driver->id]);
+	clk_disable_unprepare(drvdata->mi2s_bit_clk[dai->driver->id]);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		ret = regmap_fields_write(i2sctl->spken, id,
+					 LPAIF_I2SCTL_SPKEN_DISABLE);
+	} else  {
+		ret = regmap_fields_write(i2sctl->micen, id,
+					 LPAIF_I2SCTL_MICEN_DISABLE);
+	}
+	if (ret)
+		dev_err(dai->dev, "error writing to i2sctl reg: %d\n",
+				ret);
 }
 
 static int lpass_cpu_daiops_hw_params(struct snd_pcm_substream *substream,
@@ -308,7 +336,8 @@ static int lpass_cpu_daiops_trigger(struct snd_pcm_substream *substream,
 				ret);
 
 		clk_disable(drvdata->mi2s_bit_clk[dai->driver->id]);
-
+		break;
+	default:
 		break;
 	}
 
-- 
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is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.