linux-kernel - [RFC PATCH 1/2] ASoC: soc-dai: add flag to mute and unmute stream during trigger

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Date:   Fri, 27 Oct 2023 11:57:46 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     broonie@...nel.org
Cc:     johan@...nel.org, perex@...ex.cz, tiwai@...e.com,
        lgirdwood@...il.com, linux-kernel@...r.kernel.org,
        alsa-devel@...a-project.org,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [RFC PATCH 1/2] ASoC: soc-dai: add flag to mute and unmute stream during trigger

In some setups like Speaker amps which are very sensitive, ex: keeping them
unmute without actual data stream for very short duration results in a
static charge and results in pop and clicks. To minimize this, provide a way
to mute and unmute such codecs during trigger callbacks.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 include/sound/soc-dai.h |  1 +
 sound/soc/soc-dai.c     |  7 +++++++
 sound/soc/soc-pcm.c     | 12 ++++++++----
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
index e3906ecda740..5827b4d882fc 100644
--- a/include/sound/soc-dai.h
+++ b/include/sound/soc-dai.h
@@ -355,6 +355,7 @@ struct snd_soc_dai_ops {
 
 	/* bit field */
 	unsigned int no_capture_mute:1;
+	unsigned int mute_unmute_on_trigger:1;
 };
 
 struct snd_soc_cdai_ops {
diff --git a/sound/soc/soc-dai.c b/sound/soc/soc-dai.c
index 02dd64dea179..28d8c6c3d3b2 100644
--- a/sound/soc/soc-dai.c
+++ b/sound/soc/soc-dai.c
@@ -641,6 +641,10 @@ int snd_soc_pcm_dai_trigger(struct snd_pcm_substream *substream,
 			ret = soc_dai_trigger(dai, substream, cmd);
 			if (ret < 0)
 				break;
+
+			if (dai->driver->ops && dai->driver->ops->mute_unmute_on_trigger)
+				snd_soc_dai_digital_mute(dai, 0, substream->stream);
+
 			soc_dai_mark_push(dai, substream, trigger);
 		}
 		break;
@@ -651,6 +655,9 @@ int snd_soc_pcm_dai_trigger(struct snd_pcm_substream *substream,
 			if (rollback && !soc_dai_mark_match(dai, substream, trigger))
 				continue;
 
+			if (dai->driver->ops && dai->driver->ops->mute_unmute_on_trigger)
+				snd_soc_dai_digital_mute(dai, 1, substream->stream);
+
 			r = soc_dai_trigger(dai, substream, cmd);
 			if (r < 0)
 				ret = r; /* use last ret */
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 3aa6b988cb4b..0f9f4da25158 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -703,8 +703,10 @@ static int soc_pcm_clean(struct snd_soc_pcm_runtime *rtd,
 			if (snd_soc_dai_active(dai) == 0)
 				soc_pcm_set_dai_params(dai, NULL);
 
-			if (snd_soc_dai_stream_active(dai, substream->stream) == 0)
-				snd_soc_dai_digital_mute(dai, 1, substream->stream);
+			if (snd_soc_dai_stream_active(dai, substream->stream) ==  0) {
+				if (dai->driver->ops && !dai->driver->ops->mute_unmute_on_trigger)
+					snd_soc_dai_digital_mute(dai, 1, substream->stream);
+			}
 		}
 	}
 
@@ -898,8 +900,10 @@ static int __soc_pcm_prepare(struct snd_soc_pcm_runtime *rtd,
 	snd_soc_dapm_stream_event(rtd, substream->stream,
 			SND_SOC_DAPM_STREAM_START);
 
-	for_each_rtd_dais(rtd, i, dai)
-		snd_soc_dai_digital_mute(dai, 0, substream->stream);
+	for_each_rtd_dais(rtd, i, dai) {
+		if (dai->driver->ops && !dai->driver->ops->mute_unmute_on_trigger)
+			snd_soc_dai_digital_mute(dai, 0, substream->stream);
+	}
 
 out:
 	return soc_pcm_ret(rtd, ret);
-- 
2.21.0