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Subject[PATCH 2/3] ASoC: fsl_sai: Don't reset FIFO until TE/RE bit is unset
Date
From: Nicolin Chen <Guangyu.Chen@freescale.com>

TE/RE bit of T/RCSR will remain set untill the current frame is physically
finished. The FIFO reset operation should wait this bit's totally cleared
rather than ignoring its status which might cause TE/RE disabling failed.

This patch adds delay and timeout to wait for its completion before FIFO
reset.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
sound/soc/fsl/fsl_sai.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index a437899..a79a9b0 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -327,7 +327,7 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
{
struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
- u32 xcsr;
+ u32 xcsr, count = 100;

/*
* The transmitter bit clock and frame sync are to be
@@ -369,11 +369,20 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
if (!(xcsr & FSL_SAI_CSR_FRDE)) {
/* Disable both directions and reset their FIFOs */
regmap_update_bits(sai->regmap, FSL_SAI_TCSR,
- FSL_SAI_CSR_TERE | FSL_SAI_CSR_FR,
- FSL_SAI_CSR_FR);
+ FSL_SAI_CSR_TERE, 0);
regmap_update_bits(sai->regmap, FSL_SAI_RCSR,
- FSL_SAI_CSR_TERE | FSL_SAI_CSR_FR,
- FSL_SAI_CSR_FR);
+ FSL_SAI_CSR_TERE, 0);
+
+ /* TERE will remain set till the end of current frame */
+ do {
+ udelay(10);
+ regmap_read(sai->regmap, FSL_SAI_xCSR(tx), &xcsr);
+ } while (--count && xcsr & FSL_SAI_CSR_TERE);
+
+ regmap_update_bits(sai->regmap, FSL_SAI_TCSR,
+ FSL_SAI_CSR_FR, FSL_SAI_CSR_FR);
+ regmap_update_bits(sai->regmap, FSL_SAI_RCSR,
+ FSL_SAI_CSR_FR, FSL_SAI_CSR_FR);
}
break;
default:
--
1.8.4


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