[alsa-devel] [PATCH v2] ASoC: fsl_ssi: Fix channel swap on playback start

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam at nxp.com>

Commit f8fdf5375e2005f2 ("ASoC: fsl-ssi: add SSIEN errata work around")
implemented  the workaround for the following erratum found on i.MX35
errata document:

ENGcm06222: SSI:Transmission does not take place in bit length early
frame sync configuration

and also for ENGcm06222 from the same document.

However it has been only applied for AC97 mode. Apply it to I2S mode
as well so that it can fix audio channel swap during playback start.

The channel swap can be noticed in about 10% of the times an audio track
starts.

With the recommended workaround in place no more channel swap
happened after running audio start/stop sequence in more than
2000 times.

Tested on a mx6dl-wandboard.

Signed-off-by: Fabio Estevam <fabio.estevam at nxp.com>
---
Changes since v1:
- Do not impact  61fcf10a0ee44763e0 ("ASoC: fsl_ssi: Fix channel slipping in
Playback at startup")

 sound/soc/fsl/fsl_ssi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index 17f92b8..549b2a5 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -575,7 +575,9 @@ static void fsl_ssi_config(struct fsl_ssi_private *ssi_private, bool enable,
 					"Timeout waiting TX FIFO filling\n");
 			}
 		}
-		regmap_update_bits(regs, CCSR_SSI_SCR, vals->scr, vals->scr);
+		regmap_update_bits(regs, CCSR_SSI_SCR,
+			CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_TE | CCSR_SSI_SCR_RE,
+			CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_TE | CCSR_SSI_SCR_RE);
 	}
 }
 
-- 
2.7.4