linux-kernel - RE: [PATCH] ASoC: fsl_sai: Fix Bit Clock Polarity configurations

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Date:	Fri, 4 Apr 2014 07:37:00 +0000
From:	"Li.Xiubo@...escale.com" <Li.Xiubo@...escale.com>
To:	"guangyu.chen@...escale.com" <guangyu.chen@...escale.com>,
	"broonie@...nel.org" <broonie@...nel.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	"timur@...i.org" <timur@...i.org>
Subject: RE: [PATCH] ASoC: fsl_sai: Fix Bit Clock Polarity configurations


> Subject: [PATCH] ASoC: fsl_sai: Fix Bit Clock Polarity configurations
> 
> The BCP bit in TCR4/RCR4 register rules as followings:
>   0 Bit clock is active high with drive outputs on rising edge
>     and sample inputs on falling edge.
>   1 Bit clock is active low with drive outputs on falling edge
>     and sample inputs on rising edge.
> 
> For all formats currently supported in the fsl_sai driver, they're exactly
> sending data on the falling edge and sampling on the rising edge.
> 
> However, the driver clears this BCP bit for all of them which results click
> noise when working with SGTL5000 and big noise with WM8962.
> 
> Thus this patch corrects the BCP settings for all the formats here to fix
> the nosie issue.
> 
> Signed-off-by: Nicolin Chen <Guangyu.Chen@...escale.com>
> ---

Good catch.

Acked-by: Xiubo Li <Li.Xiubo@...escale.com>

Thanks,
--

BRs,
Xiubo


>  sound/soc/fsl/fsl_sai.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> index 99051c7..9bbebea 100644
> --- a/sound/soc/fsl/fsl_sai.c
> +++ b/sound/soc/fsl/fsl_sai.c
> @@ -180,7 +180,7 @@ static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai
> *cpu_dai,
>  		 * that is, together with the last bit of the previous
>  		 * data word.
>  		 */
> -		val_cr2 &= ~FSL_SAI_CR2_BCP;
> +		val_cr2 |= FSL_SAI_CR2_BCP;
>  		val_cr4 |= FSL_SAI_CR4_FSE | FSL_SAI_CR4_FSP;
>  		break;
>  	case SND_SOC_DAIFMT_LEFT_J:
> @@ -188,7 +188,7 @@ static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai
> *cpu_dai,
>  		 * Frame high, one word length for frame sync,
>  		 * frame sync asserts with the first bit of the frame.
>  		 */
> -		val_cr2 &= ~FSL_SAI_CR2_BCP;
> +		val_cr2 |= FSL_SAI_CR2_BCP;
>  		val_cr4 &= ~(FSL_SAI_CR4_FSE | FSL_SAI_CR4_FSP);
>  		break;
>  	case SND_SOC_DAIFMT_DSP_A:
> @@ -198,7 +198,7 @@ static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai
> *cpu_dai,
>  		 * that is, together with the last bit of the previous
>  		 * data word.
>  		 */
> -		val_cr2 &= ~FSL_SAI_CR2_BCP;
> +		val_cr2 |= FSL_SAI_CR2_BCP;
>  		val_cr4 &= ~FSL_SAI_CR4_FSP;
>  		val_cr4 |= FSL_SAI_CR4_FSE;
>  		sai->is_dsp_mode = true;
> @@ -208,7 +208,7 @@ static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai
> *cpu_dai,
>  		 * Frame high, one bit for frame sync,
>  		 * frame sync asserts with the first bit of the frame.
>  		 */
> -		val_cr2 &= ~FSL_SAI_CR2_BCP;
> +		val_cr2 |= FSL_SAI_CR2_BCP;
>  		val_cr4 &= ~(FSL_SAI_CR4_FSE | FSL_SAI_CR4_FSP);
>  		sai->is_dsp_mode = true;
>  		break;
> --
> 1.8.4
> 

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