diff options
| author | Richard Fitzgerald <[email protected]> | 2021-08-05 17:11:10 +0100 |
|---|---|---|
| committer | Mark Brown <[email protected]> | 2021-08-05 23:33:45 +0100 |
| commit | c76d572c1ec82e305c97219e28952966958bc31a (patch) | |
| tree | 441f362a356f36dbc38c4b2938ba01f1476938ce | |
| parent | 24cdbb79bbfe690f7fe87507dd0489670eddb5b0 (diff) | |
ASoC: cs42l42: Assume 24-bit samples are in 32-bit slots
If the machine driver doesn't call snd_soc_dai_set_sysclk() the
SCLK is assumed to be sample_rate * sample_bits * 2 (that is, the
rate necessary for a standard I2S frame).
But 24-bit samples can be sent in either a 24-bit slot or a 32-bit
slot. If the PLL is configured for a 24-bit slot, but a 32-bit slot is
used, cs42l42 will be overclocked.
Ultimately it is the machine driver's responsibilty to call
snd_soc_dai_set_sysclk() if SLK will be different from the standard
I2S rate. However, it is convenient to assume 32-bit slots to allow
this common case without needing special machine driver support. The
machine driver then only has to set SCLK if the slots are 24-bit, but
if it fails to do this cs42l42 won't be overclocked.
Signed-off-by: Richard Fitzgerald <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>
| -rw-r--r-- | sound/soc/codecs/cs42l42.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/sound/soc/codecs/cs42l42.c b/sound/soc/codecs/cs42l42.c index b2ee51443a22..3677ed4670d0 100644 --- a/sound/soc/codecs/cs42l42.c +++ b/sound/soc/codecs/cs42l42.c @@ -844,6 +844,13 @@ static int cs42l42_pcm_hw_params(struct snd_pcm_substream *substream, if (channels == 1) cs42l42->bclk *= 2; + /* + * Assume 24-bit samples are in 32-bit slots, to prevent SCLK being + * more than assumed (which would result in overclocking). + */ + if (params_width(params) == 24) + cs42l42->bclk = (cs42l42->bclk / 3) * 4; + switch(substream->stream) { case SNDRV_PCM_STREAM_CAPTURE: if (channels == 2) { |