[PATCH] ASoC: fsl_sai: Enable transmitter when generating MCLK

[Shengjiu Wang]

On Tue, Nov 8, 2022 at 5:52 AM Marek Vasut <marex at denx.de> wrote:

> For SAI to generate MCLK on external SoC pad, the transmitter must be
> enabled as well. With transmitter disabled, no clock are generated.
> Enable the transmitter using the TERE bit.
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
> Cc: Fabio Estevam <festevam at gmail.com>
> Cc: Jaroslav Kysela <perex at perex.cz>
> Cc: Liam Girdwood <lgirdwood at gmail.com>
> Cc: Mark Brown <broonie at kernel.org>
> Cc: Nicolin Chen <nicoleotsuka at gmail.com>
> Cc: Shengjiu Wang <shengjiu.wang at gmail.com>
> Cc: Takashi Iwai <tiwai at suse.com>
> Cc: Xiubo Li <Xiubo.Lee at gmail.com>
> To: alsa-devel at alsa-project.org
> ---
>  sound/soc/fsl/fsl_sai.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> index 1c9be8a5dcb13..98c62027e5799 100644
> --- a/sound/soc/fsl/fsl_sai.c
> +++ b/sound/soc/fsl/fsl_sai.c
> @@ -503,6 +503,10 @@ static int fsl_sai_set_bclk(struct snd_soc_dai *dai,
> bool tx, u32 freq)
>                 /* SAI is in master mode at this point, so enable MCLK */
>                 regmap_update_bits(sai->regmap, FSL_SAI_MCTL,
>                                    FSL_SAI_MCTL_MCLK_EN,
> FSL_SAI_MCTL_MCLK_EN);
> +
> +               /* Transmitter must be enabled to generate MCLK on pad */
> +               regmap_update_bits(sai->regmap, FSL_SAI_xCSR(1, ofs),
> +                                  FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
>

No need to fix the transmitter,   FSL_SAI_xCSR(tx, ofs) should work also.



>         }
>
>         return 0;
> @@ -1445,6 +1449,11 @@ static int fsl_sai_probe(struct platform_device
> *pdev)
>             sai->soc_data->max_register >= FSL_SAI_MCTL) {
>                 regmap_update_bits(sai->regmap, FSL_SAI_MCTL,
>                                    FSL_SAI_MCTL_MCLK_EN,
> FSL_SAI_MCTL_MCLK_EN);
> +
> +               /* Transmitter must be enabled to generate MCLK on pad */
> +               regmap_update_bits(sai->regmap,
> +                                  FSL_SAI_xCSR(1,
> sai->soc_data->reg_offset),
> +                                  FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
>

After one time playback or recording,  the TERE is disabled, so this changes
in probe() only for the first time.  There is the same issue for the second
time.

best regards
wang shengjiu

>         }
>
>         ret = pm_runtime_put_sync(dev);
> --
> 2.35.1
>
>