[PATCH v2 1/2] ASoC: sophgo: cv1800b: document DAC overwrite handling
"Anton D. Stavinskii" <[email protected]>
| Newsgroups | dev.linux.lists.sophgo,org.infradead.lists.linux-riscv,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel,org.kernel.vger.linux-sound |
|---|---|
| Message-ID | <[email protected]> |
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 <[email protected]> --- sound/soc/sophgo/cv1800b-sound-dac.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/sound/soc/sophgo/cv1800b-sound-dac.c b/sound/soc/sophgo/cv1800b-sound-dac.c index ccf386174639..135322bcf6ad 100644 --- a/sound/soc/sophgo/cv1800b-sound-dac.c +++ b/sound/soc/sophgo/cv1800b-sound-dac.c @@ -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); -- 2.43.0