Re: [PATCH v1 3/4] ASoC: Intel: bytcr_rt5640: use devm_clk_get_optional() for mclk

[Pierre-Louis Bossart]

On 10/6/21 10:04 AM, Andy Shevchenko wrote:
> The devm_clk_get_optional() helper returns NULL when devm_clk_get()
> returns -ENOENT. This makes things slightly cleaner. The added benefit
> is mostly cosmetic.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
>  sound/soc/intel/boards/bytcr_rt5640.c | 75 ++++++++++++---------------
>  1 file changed, 32 insertions(+), 43 deletions(-)
> 
> diff --git a/sound/soc/intel/boards/bytcr_rt5640.c b/sound/soc/intel/boards/bytcr_rt5640.c
> index 0f609a0b3527..2e7d45f0f05d 100644
> --- a/sound/soc/intel/boards/bytcr_rt5640.c
> +++ b/sound/soc/intel/boards/bytcr_rt5640.c
> @@ -269,13 +269,10 @@ static int platform_clock_control(struct snd_soc_dapm_widget *w,
>  		return -EIO;
>  
>  	if (SND_SOC_DAPM_EVENT_ON(event)) {
> -		if (byt_rt5640_quirk & BYT_RT5640_MCLK_EN) {

same comment as for rt5651, I don't see the point of removing the test
on this quirk?

> -			ret = clk_prepare_enable(priv->mclk);
> -			if (ret < 0) {
> -				dev_err(card->dev,
> -					"could not configure MCLK state\n");
> -				return ret;
> -			}
> +		ret = clk_prepare_enable(priv->mclk);
> +		if (ret < 0) {
> +			dev_err(card->dev, "could not configure MCLK state\n");
> +			return ret;
>  		}
>  		ret = byt_rt5640_prepare_and_enable_pll1(codec_dai, 48000);
>  	} else {
> @@ -287,10 +284,8 @@ static int platform_clock_control(struct snd_soc_dapm_widget *w,
>  		ret = snd_soc_dai_set_sysclk(codec_dai, RT5640_SCLK_S_RCCLK,
>  					     48000 * 512,
>  					     SND_SOC_CLOCK_IN);
> -		if (!ret) {
> -			if (byt_rt5640_quirk & BYT_RT5640_MCLK_EN)
> -				clk_disable_unprepare(priv->mclk);
> -		}
> +		if (!ret)
> +			clk_disable_unprepare(priv->mclk);
>  	}
>  
>  	if (ret < 0) {
> @@ -1217,30 +1212,25 @@ static int byt_rt5640_init(struct snd_soc_pcm_runtime *runtime)
>  			return ret;
>  	}
>  
> -	if (byt_rt5640_quirk & BYT_RT5640_MCLK_EN) {
> -		/*
> -		 * The firmware might enable the clock at
> -		 * boot (this information may or may not
> -		 * be reflected in the enable clock register).
> -		 * To change the rate we must disable the clock
> -		 * first to cover these cases. Due to common
> -		 * clock framework restrictions that do not allow
> -		 * to disable a clock that has not been enabled,
> -		 * we need to enable the clock first.
> -		 */
> -		ret = clk_prepare_enable(priv->mclk);
> -		if (!ret)
> -			clk_disable_unprepare(priv->mclk);
> -
> -		if (byt_rt5640_quirk & BYT_RT5640_MCLK_25MHZ)
> -			ret = clk_set_rate(priv->mclk, 25000000);
> -		else
> -			ret = clk_set_rate(priv->mclk, 19200000);
> +	/*
> +	 * The firmware might enable the clock at boot (this information
> +	 * may or may not be reflected in the enable clock register).
> +	 * To change the rate we must disable the clock first to cover
> +	 * these cases. Due to common clock framework restrictions that
> +	 * do not allow to disable a clock that has not been enabled,
> +	 * we need to enable the clock first.
> +	 */
> +	ret = clk_prepare_enable(priv->mclk);
> +	if (!ret)
> +		clk_disable_unprepare(priv->mclk);
>  
> -		if (ret) {
> -			dev_err(card->dev, "unable to set MCLK rate\n");
> -			return ret;
> -		}
> +	if (byt_rt5640_quirk & BYT_RT5640_MCLK_25MHZ)
> +		ret = clk_set_rate(priv->mclk, 25000000);
> +	else
> +		ret = clk_set_rate(priv->mclk, 19200000);
> +	if (ret) {
> +		dev_err(card->dev, "unable to set MCLK rate\n");
> +		return ret;
>  	}
>  
>  	if (BYT_RT5640_JDSRC(byt_rt5640_quirk)) {
> @@ -1653,7 +1643,7 @@ static int snd_byt_rt5640_mc_probe(struct platform_device *pdev)
>  		byt_rt5640_dais[dai_index].cpus->dai_name = "ssp0-port";
>  
>  	if (byt_rt5640_quirk & BYT_RT5640_MCLK_EN) {
> -		priv->mclk = devm_clk_get(dev, "pmc_plt_clk_3");
> +		priv->mclk = devm_clk_get_optional(dev, "pmc_plt_clk_3");
>  		if (IS_ERR(priv->mclk)) {
>  			ret_val = PTR_ERR(priv->mclk);
>  
> @@ -1661,15 +1651,14 @@ static int snd_byt_rt5640_mc_probe(struct platform_device *pdev)
>  				"Failed to get MCLK from pmc_plt_clk_3: %d\n",
>  				ret_val);
>  
> -			/*
> -			 * Fall back to bit clock usage for -ENOENT (clock not
> -			 * available likely due to missing dependencies), bail
> -			 * for all other errors, including -EPROBE_DEFER
> -			 */
> -			if (ret_val != -ENOENT)
> -				goto err;
> -			byt_rt5640_quirk &= ~BYT_RT5640_MCLK_EN;
> +			goto err;
>  		}
> +		/*
> +		 * Fall back to bit clock usage when clock is not
> +		 * available likely due to missing dependencies.
> +		 */
> +		if (!priv->mclk)
> +			byt_rt5640_quirk &= ~BYT_RT5640_MCLK_EN;
>  	}
>  
>  	if (byt_rt5640_quirk & BYT_RT5640_NO_SPEAKERS) {
>