Re: [PATCH] ASoC: fsl_sai: fix Rx synchrounous mode

From: Nicolin Chen
Date: Thu Oct 22 2015 - 14:57:52 EST


On Mon, Oct 19, 2015 at 05:42:23PM -0700, Stefan Agner wrote:
> When using the Rx clock for both, transmitter and receiver, the
> transmitter needs to be set to synchronous with receiver.
>
> This reverts 855675f6e6a6 ("ASoC: fsl_sai: Set SYNC bit of TCR2 to
> Asynchronous Mode"), which, judiging from the commit log, seems to
> mixed up between the two synchronous modes: The boolean

Actually my original patch I sent to the mail list was different:
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-August/079639.html

It should be applied before the asynchronous patches however they
are somehow disordered. I guess that's why now the commit appears
in such confusing way. But anyway it's a bug I should have noticed
long time ago.

Thanks a lot

> sai->synchronous[TX] is indicating wheather the SAI should work in
> Rx synchronous mode (sync Tx with Rx), hence if the value is true,
> the SYNC field of TCR2 needs to be set to 0x1 ("Synchronous with
> receiver").
>
> Signed-off-by: Stefan Agner <stefan@xxxxxxxx>

Acked-by: Nicolin Chen <nicoleotsuka@xxxxxxxxx>

> ---
> Hi Nicolin,
>
> I got this reported from a customer, he tried to use the device
> tree property "fsl,sai-synchronous-rx" according to the description
> but it failed. In a quick test, setting the SYNC field of TCR2 to
> 0x1 helped in his case. So I think this here is right. But given
> that you chaged the very same line can you review that again and
> give me a Ack/Nack?
>
> --
> Stefan
>
> sound/soc/fsl/fsl_sai.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> index a18fd92..1f0e552 100644
> --- a/sound/soc/fsl/fsl_sai.c
> +++ b/sound/soc/fsl/fsl_sai.c
> @@ -454,7 +454,8 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
> * Rx sync with Tx clocks: Clear SYNC for Tx, set it for Rx.
> * Tx sync with Rx clocks: Clear SYNC for Rx, set it for Tx.
> */
> - regmap_update_bits(sai->regmap, FSL_SAI_TCR2, FSL_SAI_CR2_SYNC, 0);
> + regmap_update_bits(sai->regmap, FSL_SAI_TCR2, FSL_SAI_CR2_SYNC,
> + sai->synchronous[TX] ? FSL_SAI_CR2_SYNC : 0);
> regmap_update_bits(sai->regmap, FSL_SAI_RCR2, FSL_SAI_CR2_SYNC,
> sai->synchronous[RX] ? FSL_SAI_CR2_SYNC : 0);
>
> --
> 2.6.1
>
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