Subject: Re: [alsa-devel] [PATCH V1] ASoC: fsl_ssi: refine ipg clock usage in this module

From: Markus Pargmann <[email-masked]>
Date: Tue, 9 Sep 2014 11:49:13 +0200

Hi,

On Tue, Sep 09, 2014 at 05:18:07PM +0800, Shengjiu Wang wrote:
> Move the ipg clock enable and disable operation to startup and shutdown,
> that is only enable ipg clock when ssi is working. we don't need to enable
> ipg clock in probe.
> Another register accessing need the ipg clock, so use devm_regmap_init_mmio_clk
> instead of devm_regmap_init_mmio.
> 
> Signed-off-by: Shengjiu Wang <[email-masked]>
> ---
>  sound/soc/fsl/fsl_ssi.c |   38 +++++++++++++++++++++++++++-----------
>  1 file changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
> index 2fc3e66..d32d0f5 100644
> --- a/sound/soc/fsl/fsl_ssi.c
> +++ b/sound/soc/fsl/fsl_ssi.c
> @@ -531,6 +531,9 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
>  	struct fsl_ssi_private *ssi_private =
>  		snd_soc_dai_get_drvdata(rtd->cpu_dai);
>  
> +	if (ssi_private->soc->imx)
> +		clk_prepare_enable(ssi_private->clk);
> +
>  	/* When using dual fifo mode, it is safer to ensure an even period
>  	 * size. If appearing to an odd number while DMA always starts its
>  	 * task from fifo0, fifo1 would be neglected at the end of each
> @@ -544,6 +547,22 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
>  }
>  
>  /**
> + * fsl_ssi_shutdown: shutdown the SSI
> + *
> + */
> +static void fsl_ssi_shutdown(struct snd_pcm_substream *substream,
> +                             struct snd_soc_dai *dai)
> +{
> +	struct snd_soc_pcm_runtime *rtd = substream->private_data;
> +	struct fsl_ssi_private *ssi_private =
> +		snd_soc_dai_get_drvdata(rtd->cpu_dai);
> +
> +	if (ssi_private->soc->imx)
> +		clk_disable_unprepare(ssi_private->clk);
> +
> +}
> +
> +/**
>   * fsl_ssi_set_bclk - configure Digital Audio Interface bit clock
>   *
>   * Note: This function can be only called when using SSI as DAI master
> @@ -1043,6 +1062,7 @@ static int fsl_ssi_dai_probe(struct snd_soc_dai *dai)
>  
>  static const struct snd_soc_dai_ops fsl_ssi_dai_ops = {
>  	.startup	= fsl_ssi_startup,
> +	.shutdown       = fsl_ssi_shutdown,
>  	.hw_params	= fsl_ssi_hw_params,
>  	.hw_free	= fsl_ssi_hw_free,
>  	.set_fmt	= fsl_ssi_set_dai_fmt,
> @@ -1168,16 +1188,10 @@ static int fsl_ssi_imx_probe(struct platform_device *pdev,
>  	u32 dmas[4];
>  	int ret;
>  
> -	ssi_private->clk = devm_clk_get(&pdev->dev, NULL);
> +	ssi_private->clk = devm_clk_get(&pdev->dev, "ipg");

This does not work for most imx SoCs at the moment. imx27, imx35, imx51
etc. do not have clock-names defined in the devicetree.

Best regards,

Markus

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