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ASoC: fsl_sai: Set SAI Channel Mode to Output Mode

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Transmit data pins will output zero when slots are masked or channels
are disabled. In CHMOD TDM mode, transmit data pins are tri-stated when
slots are masked or channels are disabled. When data pins are tri-stated,
there is noise on some channels when FS clock value is high and data is
read while fsclk is transitioning from high to low.

Signed-off-by: Cosmin-Gabriel Samoila <cosmin.samoila@nxp.com>
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/1599112427-22038-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Shengjiu Wang 2020-09-03 13:53:47 +08:00 committed by Mark Brown
parent 770f58d7d2
commit f4c4b1bb2f
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
2 changed files with 10 additions and 2 deletions
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10
sound/soc/fsl/fsl_sai.c
View File

@ -489,6 +489,10 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
val_cr4 |= FSL_SAI_CR4_FRSZ(slots);
/* Set to output mode to avoid tri-stated data pins */
if (tx)
val_cr4 |= FSL_SAI_CR4_CHMOD;
/*
* For SAI master 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),
@ -497,7 +501,8 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
if (!sai->is_slave_mode && 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_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK |
FSL_SAI_CR4_CHMOD_MASK,
val_cr4);
regmap_update_bits(sai->regmap, FSL_SAI_xCR5(!tx, ofs),
FSL_SAI_CR5_WNW_MASK | FSL_SAI_CR5_W0W_MASK |
@ -508,7 +513,8 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
FSL_SAI_CR3_TRCE_MASK,
FSL_SAI_CR3_TRCE((1 << pins) - 1));
regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx, ofs),
FSL_SAI_CR4_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK,
FSL_SAI_CR4_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK |
FSL_SAI_CR4_CHMOD_MASK,
val_cr4);
regmap_update_bits(sai->regmap, FSL_SAI_xCR5(tx, ofs),
FSL_SAI_CR5_WNW_MASK | FSL_SAI_CR5_W0W_MASK |

2
sound/soc/fsl/fsl_sai.h
View File

@ -119,6 +119,8 @@
#define FSL_SAI_CR4_FRSZ_MASK (0x1f << 16)
#define FSL_SAI_CR4_SYWD(x) (((x) - 1) << 8)
#define FSL_SAI_CR4_SYWD_MASK (0x1f << 8)
#define FSL_SAI_CR4_CHMOD BIT(5)
#define FSL_SAI_CR4_CHMOD_MASK BIT(5)
#define FSL_SAI_CR4_MF BIT(4)
#define FSL_SAI_CR4_FSE BIT(3)
#define FSL_SAI_CR4_FSP BIT(1)