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Subject[PATCH] ASoC: AMD: Add delay before starting to capture
Date
On capture through dmic we observe a glitch at the start of record.
This is because we start capturing even before dmic is ready to send
out data. The glitch seen last for ~20msec.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
---
sound/soc/amd/acp-da7219-max98357a.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/sound/soc/amd/acp-da7219-max98357a.c b/sound/soc/amd/acp-da7219-max98357a.c
index a5daad9..72b1cf4 100644
--- a/sound/soc/amd/acp-da7219-max98357a.c
+++ b/sound/soc/amd/acp-da7219-max98357a.c
@@ -44,6 +44,8 @@

#define CZ_PLAT_CLK 48000000
#define DUAL_CHANNEL 2
+#define ADAU7002_DELAY_MS 20
+

static struct snd_soc_jack cz_jack;
static struct clk *da7219_dai_clk;
@@ -213,6 +215,7 @@ static int cz_dmic0_startup(struct snd_pcm_substream *substream)
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct snd_soc_card *card = rtd->card;
struct acp_platform_info *machine = snd_soc_card_get_drvdata(card);
+ int ret;

/*
* On this platform for PCM device we support stereo
@@ -225,7 +228,17 @@ static int cz_dmic0_startup(struct snd_pcm_substream *substream)
&constraints_rates);

machine->cap_i2s_instance = I2S_BT_INSTANCE;
- return da7219_clk_enable(substream);
+ ret = da7219_clk_enable(substream);
+ if (ret)
+ return ret;
+ /*
+ * On some platforms, it takes ~20 msec for PDM DMICs and ADAU7002
+ * to settle and start producing proper audio data.
+ */
+ msleep(ADAU7002_DELAY_MS);
+ /* Delay in frames for 48Khz, 16bit, 2 channel */
+ runtime->delay = ADAU7002_DELAY_MS * 48;
+ return 0;
}

static int cz_dmic1_startup(struct snd_pcm_substream *substream)
@@ -234,6 +247,7 @@ static int cz_dmic1_startup(struct snd_pcm_substream *substream)
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct snd_soc_card *card = rtd->card;
struct acp_platform_info *machine = snd_soc_card_get_drvdata(card);
+ int ret;

/*
* On this platform for PCM device we support stereo
@@ -247,7 +261,17 @@ static int cz_dmic1_startup(struct snd_pcm_substream *substream)

machine->cap_i2s_instance = I2S_SP_INSTANCE;
machine->capture_channel = CAP_CHANNEL0;
- return da7219_clk_enable(substream);
+ ret = da7219_clk_enable(substream);
+ if (ret)
+ return ret;
+ /*
+ * On some platforms, it takes ~20 msec for PDM DMICs and ADAU7002
+ * to settle and start producing proper audio data.
+ */
+ msleep(ADAU7002_DELAY_MS);
+ /* Delay in frames for 48Khz, 16bit, 2 channel */
+ runtime->delay = ADAU7002_DELAY_MS * 48;
+ return 0;
}

static void cz_dmic_shutdown(struct snd_pcm_substream *substream)
--
1.9.1
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