On Tue, Jul 7, 2026 at 4:47 PM Chancel Liu <[email protected]> wrote: > > From: Chancel Liu <[email protected]> > > When the BCLK divider ratio is 1:1, fsl_sai_set_bclk() enables bypass > mode by setting BYP, but never clears the bit. The BYP=1 value remains > in the regcache, and is restored by regcache_sync() on the next runtime > resume. > > Since BYP=1 combined with BCD=1 immediately outputs the ungated MCLK > as BCLK without waiting for BCE/TE/RE to be enabled, the clock is > driven prematurely before the stream is fully configured, causing > noise on some codecs. > > Fix this by clearing BYP and BCI together in fsl_sai_config_disable(). > Also clear BCI, which is programmed together with the bypass case in > synchronous mode, so the cached CR2 state is clean and regcache_sync() > will not restore bypass mode prematurely on the next resume. > > Fixes: a50b7926d015 ("ASoC: fsl_sai: implement 1:1 bclk:mclk ratio support") > Signed-off-by: Chancel Liu <[email protected]>
Reviewed-by: Shengjiu Wang <[email protected]> Best regards Shengjiu Wang > --- > sound/soc/fsl/fsl_sai.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c > index 9661602b53c5..4c0626d572a5 100644 > --- a/sound/soc/fsl/fsl_sai.c > +++ b/sound/soc/fsl/fsl_sai.c > @@ -847,6 +847,9 @@ static void fsl_sai_config_disable(struct fsl_sai *sai, > int dir) > regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx, ofs), > FSL_SAI_CSR_FR, FSL_SAI_CSR_FR); > > + regmap_update_bits(sai->regmap, FSL_SAI_xCR2(tx, ofs), > + FSL_SAI_CR2_BCI | FSL_SAI_CR2_BYP, 0); > + > /* > * For sai master mode, after several open/close sai, > * there will be no frame clock, and can't recover > -- > 2.50.1 >
