ASoC: fsl_sai: Fix sync error in consumer mode

When configured for default synchronisation (Rx syncs to Tx) and the
SAI operates in consumer mode (clocks provided externally to Tx), a
synchronisation error occurs on Tx on the first attempt after device
initialisation when the playback stream is started while a capture
stream is already active. This results in channel shift/swap on the
playback stream.
Subsequent streams (ie after that first failing one) always work
correctly, no matter the order, with or without the other stream active.

This issue was observed (and fix tested) on an i.MX6UL board connected
to an ADAU1761 codec, where the codec provides both frame and bit clock
(connected to TX pins).

To fix this, always initialize the 'other' xCR4 and xCR5 registers when
we're starting a stream which is synced to the opposite one, irregardless
of the producer/consumer status.

Fixes: 51659ca069ce ("ASoC: fsl-sai: set xCR4/xCR5/xMR for SAI master mode")
Signed-off-by: Maarten Zanders <maarten@zanders.be>
Reviewed-by: Shengjiu Wang <shengjiu.wang@gmail.com>
Link: https://patch.msgid.link/20251024135716.584265-1-maarten@zanders.be
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index 65093325a6b6f4c7588176466004123a349518dc..72bfc91e21b9b4c9f410d382e6e9ab4effb5013a 100644 (file)
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -652,12 +652,12 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
                val_cr4 |= FSL_SAI_CR4_CHMOD;
 
        /*
-        * For SAI provider mode, when Tx(Rx) sync with Rx(Tx) clock, Rx(Tx) will
-        * generate bclk and frame clock for Tx(Rx), we should set RCR4(TCR4),
-        * RCR5(TCR5) for playback(capture), or there will be sync error.
+        * When Tx(Rx) sync with Rx(Tx) clock, Rx(Tx) will provide bclk and
+        * frame clock for Tx(Rx). We should set RCR4(TCR4), RCR5(TCR5)
+        * for playback(capture), or there will be sync error.
         */
 
-       if (!sai->is_consumer_mode[tx] && fsl_sai_dir_is_synced(sai, adir)) {
+       if (fsl_sai_dir_is_synced(sai, adir)) {
                regmap_update_bits(sai->regmap, FSL_SAI_xCR4(!tx, ofs),
                                   FSL_SAI_CR4_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK |
                                   FSL_SAI_CR4_CHMOD_MASK,