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ASoC: sophgo: cv1800b: document DAC overwrite handling

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Add comments to cv1800b_dac_mute() and its caller to explain how the
overwrite mechanism works and why we force it off before playback.

Signed-off-by: Anton D. Stavinskii <stavinsky@gmail.com>
Link: https://patch.msgid.link/20260127-incremental-for-i2s-dvier-v2-1-5f66b841f63d@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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Anton D. Stavinskii 2026-01-27 23:08:19 +04:00 • committed by Mark Brown
parent b3eb755e2d
commit a8e3e48829
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1 changed files with 5 additions and 1 deletions
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6
sound/soc/sophgo/cv1800b-sound-dac.c
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@ -57,6 +57,10 @@ static void cv1800b_dac_enable(struct cv1800b_priv *priv, bool enable)
writel(val, priv->regs + CV1800B_TXDAC_CTRL0);
}
/*
* Control the DAC overwrite bits. When enabled, the DAC outputs the fixed
* overwrite value instead of samples from the I2S input.
*/
static void cv1800b_dac_mute(struct cv1800b_priv *priv, bool enable)
{
u32 val;
@ -105,7 +109,7 @@ static int cv1800b_dac_hw_params(struct snd_pcm_substream *substream,
dev_err(priv->dev, "rate %u is not supported\n", rate);
return -EINVAL;
}
/* Clear DAC overwrite so playback uses I2S data. */
cv1800b_dac_mute(priv, false);
/* minimal decimation for 48kHz is 64*/
ret = cv1800b_dac_decimation(priv, DECIMATION_64);