Re: [alsa-devel] [PATCH 3/4] ASoC: da7213: Refactor sysclk(), pll() functions to improve handling

[Peter Meerwald-Stadler]

> Currently the handling of the PLL in the driver is a little clunky,
> and not ideal for all modes. This patch updates the code to make it
> cleaner and more sensible for the various PLL states.
> 
> Key items of note are:
>  - MCLK squaring is now handled directly as part of the sysclk()
>    function, removing the need for a private flag to set this feature.
>  - All PLL modes are defined as an enum, and are handled as a case
>    statement in pll() function to clean up configuration. This also
>    removes any need for a private flag for SRM.
>  - For 32KHz mode, checks are made on codec master mode and correct
>    MCLK rates, to avoid incorrect usage of PLL for this operation.
>  - For 32KHz mode, SRM flag now correctly enabled and fout set to
>    sensible value to achieve appropriate PLL dividers.

thanks, looks good
Tested-by: Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx>

nitpick: add extra newline at the end of 
if (da7213->mclk_rate == 32768) block
 
> Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>
> ---
>  sound/soc/codecs/da7213.c | 85 +++++++++++++++++++++++++++--------------------
>  sound/soc/codecs/da7213.h | 12 ++++---
>  2 files changed, 57 insertions(+), 40 deletions(-)
> 
> diff --git a/sound/soc/codecs/da7213.c b/sound/soc/codecs/da7213.c
> index 7701f4e..79b8324 100644
> --- a/sound/soc/codecs/da7213.c
> +++ b/sound/soc/codecs/da7213.c
> @@ -1297,10 +1297,13 @@ static int da7213_set_dai_sysclk(struct snd_soc_dai *codec_dai,
>  
>  	switch (clk_id) {
>  	case DA7213_CLKSRC_MCLK:
> -		da7213->mclk_squarer_en = false;
> +		snd_soc_update_bits(codec, DA7213_PLL_CTRL,
> +				    DA7213_PLL_MCLK_SQR_EN, 0);
>  		break;
>  	case DA7213_CLKSRC_MCLK_SQR:
> -		da7213->mclk_squarer_en = true;
> +		snd_soc_update_bits(codec, DA7213_PLL_CTRL,
> +				    DA7213_PLL_MCLK_SQR_EN,
> +				    DA7213_PLL_MCLK_SQR_EN);
>  		break;
>  	default:
>  		dev_err(codec_dai->dev, "Unknown clock source %d\n", clk_id);
> @@ -1324,7 +1327,7 @@ static int da7213_set_dai_sysclk(struct snd_soc_dai *codec_dai,
>  	return 0;
>  }
>  
> -/* Supported PLL input frequencies are 5MHz - 54MHz. */
> +/* Supported PLL input frequencies are 32KHz, 5MHz - 54MHz. */
>  static int da7213_set_dai_pll(struct snd_soc_dai *codec_dai, int pll_id,
>  			      int source, unsigned int fref, unsigned int fout)
>  {
> @@ -1336,22 +1339,26 @@ static int da7213_set_dai_pll(struct snd_soc_dai *codec_dai, int pll_id,
>  	u32 freq_ref;
>  	u64 frac_div;
>  
> -	/* Reset PLL configuration */
> -	snd_soc_write(codec, DA7213_PLL_CTRL, 0);
> -
> -	pll_ctrl = 0;
> -
>  	/* Workout input divider based on MCLK rate */
>  	if (da7213->mclk_rate == 32768) {
> +		if (!da7213->master) {
> +			dev_err(codec->dev,
> +				"32KHz only valid if codec is clock master\n");
> +			return -EINVAL;
> +		}
> +
>  		/* 32KHz PLL Mode */
>  		indiv_bits = DA7213_PLL_INDIV_9_TO_18_MHZ;
>  		indiv = DA7213_PLL_INDIV_9_TO_18_MHZ_VAL;
> +		source = DA7213_SYSCLK_PLL_32KHZ;
>  		freq_ref = 3750000;
> -		pll_ctrl |= DA7213_PLL_32K_MODE;
> +
>  	} else {
> -		/* 5 - 54MHz MCLK */
>  		if (da7213->mclk_rate < 5000000) {
> -			goto pll_err;
> +			dev_err(codec->dev,
> +				"PLL input clock %d below valid range\n",
> +				da7213->mclk_rate);
> +			return -EINVAL;
>  		} else if (da7213->mclk_rate <= 9000000) {
>  			indiv_bits = DA7213_PLL_INDIV_5_TO_9_MHZ;
>  			indiv = DA7213_PLL_INDIV_5_TO_9_MHZ_VAL;
> @@ -1365,32 +1372,44 @@ static int da7213_set_dai_pll(struct snd_soc_dai *codec_dai, int pll_id,
>  			indiv_bits = DA7213_PLL_INDIV_36_TO_54_MHZ;
>  			indiv = DA7213_PLL_INDIV_36_TO_54_MHZ_VAL;
>  		} else {
> -			goto pll_err;
> +			dev_err(codec->dev,
> +				"PLL input clock %d above valid range\n",
> +				da7213->mclk_rate);
> +			return -EINVAL;
>  		}
>  		freq_ref = (da7213->mclk_rate / indiv);
>  	}
>  
> -	pll_ctrl |= indiv_bits;
> +	pll_ctrl = indiv_bits;
>  
> -	/* PLL Bypass mode */
> -	if (source == DA7213_SYSCLK_MCLK) {
> -		snd_soc_write(codec, DA7213_PLL_CTRL, pll_ctrl);
> +	/* Configure PLL */
> +	switch (source) {
> +	case DA7213_SYSCLK_MCLK:
> +		snd_soc_update_bits(codec, DA7213_PLL_CTRL,
> +				    DA7213_PLL_INDIV_MASK |
> +				    DA7213_PLL_MODE_MASK, pll_ctrl);
>  		return 0;
> -	}
> +	case DA7213_SYSCLK_PLL:
> +		break;
> +	case DA7213_SYSCLK_PLL_SRM:
> +		pll_ctrl |= DA7213_PLL_SRM_EN;
> +		fout = DA7213_PLL_FREQ_OUT_94310400;
> +		break;
> +	case DA7213_SYSCLK_PLL_32KHZ:
> +		if (da7213->mclk_rate != 32768) {
> +			dev_err(codec->dev,
> +				"32KHz mode only valid with 32KHz MCLK\n");
> +			return -EINVAL;
> +		}
>  
> -	/*
> -	 * If Codec is slave and SRM enabled,
> -	 * freq_out is (98304000 + 90316800)/2 = 94310400
> -	 */
> -	if (!da7213->master && da7213->srm_en) {
> +		pll_ctrl |= DA7213_PLL_32K_MODE | DA7213_PLL_SRM_EN;
>  		fout = DA7213_PLL_FREQ_OUT_94310400;
> -		pll_ctrl |= DA7213_PLL_SRM_EN;
> +		break;
> +	default:
> +		dev_err(codec->dev, "Invalid PLL config\n");
> +		return -EINVAL;
>  	}
>  
> -	/* Enable MCLK squarer if required */
> -	if (da7213->mclk_squarer_en)
> -		pll_ctrl |= DA7213_PLL_MCLK_SQR_EN;
> -
>  	/* Calculate dividers for PLL */
>  	pll_integer = fout / freq_ref;
>  	frac_div = (u64)(fout % freq_ref) * 8192ULL;
> @@ -1405,14 +1424,11 @@ static int da7213_set_dai_pll(struct snd_soc_dai *codec_dai, int pll_id,
>  
>  	/* Enable PLL */
>  	pll_ctrl |= DA7213_PLL_EN;
> -	snd_soc_write(codec, DA7213_PLL_CTRL, pll_ctrl);
> +	snd_soc_update_bits(codec, DA7213_PLL_CTRL,
> +			    DA7213_PLL_INDIV_MASK | DA7213_PLL_MODE_MASK,
> +			    pll_ctrl);
>  
>  	return 0;
> -
> -pll_err:
> -	dev_err(codec_dai->dev, "Unsupported PLL input frequency %d\n",
> -		da7213->mclk_rate);
> -	return -EINVAL;
>  }
>  
>  /* DAI operations */
> @@ -1607,9 +1623,6 @@ static int da7213_probe(struct snd_soc_codec *codec)
>  			    DA7213_ALC_CALIB_MODE_MAN, 0);
>  	da7213->alc_calib_auto = true;
>  
> -	/* Default to using SRM for slave mode */
> -	da7213->srm_en = true;
> -
>  	/* Default PC counter to free-running */
>  	snd_soc_update_bits(codec, DA7213_PC_COUNT, DA7213_PC_FREERUN_MASK,
>  			    DA7213_PC_FREERUN_MASK);
> diff --git a/sound/soc/codecs/da7213.h b/sound/soc/codecs/da7213.h
> index fbb7a35..16ef56f 100644
> --- a/sound/soc/codecs/da7213.h
> +++ b/sound/soc/codecs/da7213.h
> @@ -172,6 +172,7 @@
>  #define DA7213_PLL_32K_MODE					(0x1 << 5)
>  #define DA7213_PLL_SRM_EN					(0x1 << 6)
>  #define DA7213_PLL_EN						(0x1 << 7)
> +#define DA7213_PLL_MODE_MASK					(0x7 << 5)
>  
>  /* DA7213_DAI_CLK_MODE = 0x28 */
>  #define DA7213_DAI_BCLKS_PER_WCLK_32				(0x0 << 0)
> @@ -499,8 +500,6 @@
>  #define DA7213_ALC_AVG_ITERATIONS	5
>  
>  /* PLL related */
> -#define DA7213_SYSCLK_MCLK			0
> -#define DA7213_SYSCLK_PLL			1
>  #define DA7213_PLL_FREQ_OUT_90316800		90316800
>  #define DA7213_PLL_FREQ_OUT_98304000		98304000
>  #define DA7213_PLL_FREQ_OUT_94310400		94310400
> @@ -515,6 +514,13 @@ enum da7213_clk_src {
>  	DA7213_CLKSRC_MCLK_SQR,
>  };
>  
> +enum da7213_sys_clk {
> +	DA7213_SYSCLK_MCLK = 0,
> +	DA7213_SYSCLK_PLL,
> +	DA7213_SYSCLK_PLL_SRM,
> +	DA7213_SYSCLK_PLL_32KHZ
> +};
> +
>  /* Codec private data */
>  struct da7213_priv {
>  	struct regmap *regmap;
> @@ -522,8 +528,6 @@ struct da7213_priv {
>  	unsigned int mclk_rate;
>  	int clk_src;
>  	bool master;
> -	bool mclk_squarer_en;
> -	bool srm_en;
>  	bool alc_calib_auto;
>  	bool alc_en;
>  	struct da7213_platform_data *pdata;
> 

-- 

Peter Meerwald-Stadler
+43-664-2444418 (mobile)