When capture and playback substreams are both running at the same time, cs42l42_pcm_hw_params() would be called for each direction. The first call will configure the PLL. The second call must not write the PLL configuration registers again if the first substream is already running, as this could destabilize the PLL.
The DAI is marked symmetric sample bits and sample rate, so the two directions will always have the same SCLK (I2S always has 2 channel slots so the DAI does not need to require symmetric channels to guarantee the same SCLK). However, since cs42l42_pll_config() is checking for an active stream it may as well test that the requested SCLK is the same as the currently active configuration.
Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com --- sound/soc/codecs/cs42l42.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/sound/soc/codecs/cs42l42.c b/sound/soc/codecs/cs42l42.c index 8de23e4732b3..26f6a3510a03 100644 --- a/sound/soc/codecs/cs42l42.c +++ b/sound/soc/codecs/cs42l42.c @@ -618,6 +618,14 @@ static int cs42l42_pll_config(struct snd_soc_component *component) else clk = cs42l42->sclk;
+ /* Don't reconfigure if there is an audio stream running */ + if (cs42l42->stream_use) { + if (pll_ratio_table[cs42l42->pll_config].sclk == clk) + return 0; + else + return -EBUSY; + } + for (i = 0; i < ARRAY_SIZE(pll_ratio_table); i++) { if (pll_ratio_table[i].sclk == clk) { cs42l42->pll_config = i;