[PATCH] ASoC: fsl_sai: Fix no frame sync clock issue on i.MX8MP

[Shengjiu Wang]

On i.MX8MP, when the TERE and FSD_MSTR enabled before configuring
the word width, there will be no frame sync clock issue, because
old word width impact the generation of frame sync.

TERE enabled earlier only for i.MX8MP case for the hardware limitation,
So need to disable FSD_MSTR before configuring word width, then enable
FSD_MSTR bit for this specific case.

Fixes: 3e4a82612998 ("ASoC: fsl_sai: MCLK bind with TX/RX enable bit")
Signed-off-by: Shengjiu Wang <shengjiu.wang at nxp.com>
---
 sound/soc/fsl/fsl_sai.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index 79e7c6b98a75..32bbe5056a63 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -673,6 +673,20 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
 			   FSL_SAI_CR3_TRCE_MASK,
 			   FSL_SAI_CR3_TRCE((dl_cfg[dl_cfg_idx].mask[tx] & trce_mask)));
 
+	/*
+	 * When the TERE and FSD_MSTR enabled before configuring the word width
+	 * There will be no frame sync clock issue, because word width impact
+	 * the generation of frame sync clock.
+	 *
+	 * TERE enabled earlier only for i.MX8MP case for the hardware limitation,
+	 * We need to disable FSD_MSTR before configuring word width, then enable
+	 * FSD_MSTR bit for this specific case.
+	 */
+	if (sai->soc_data->mclk_with_tere && sai->mclk_direction_output &&
+	    !sai->is_consumer_mode)
+		regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx, ofs),
+				   FSL_SAI_CR4_FSD_MSTR, 0);
+
 	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,
@@ -680,6 +694,13 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
 	regmap_update_bits(sai->regmap, FSL_SAI_xCR5(tx, ofs),
 			   FSL_SAI_CR5_WNW_MASK | FSL_SAI_CR5_W0W_MASK |
 			   FSL_SAI_CR5_FBT_MASK, val_cr5);
+
+	/* Enable FSD_MSTR after configuring word width */
+	if (sai->soc_data->mclk_with_tere && sai->mclk_direction_output &&
+	    !sai->is_consumer_mode)
+		regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx, ofs),
+				   FSL_SAI_CR4_FSD_MSTR, FSL_SAI_CR4_FSD_MSTR);
+
 	regmap_write(sai->regmap, FSL_SAI_xMR(tx),
 		     ~0UL - ((1 << min(channels, slots)) - 1));
 
-- 
2.34.1