[alsa-devel] [PATCH v2] ASoC: rt5670: add set_bclk_ratio in dai ops

[Bard Liao]

> -----Original Message-----
> From: Pierre-Louis Bossart [mailto:pierre-louis.bossart at linux.intel.com]
> Sent: Tuesday, September 12, 2017 10:54 PM
> To: Bard Liao; broonie at kernel.org; lgirdwood at gmail.com
> Cc: Oder Chiou; Jack Yu; alsa-devel at alsa-project.org; lars at metafoo.de;
> tiwai at suse.de; Shuming [范書銘]; Flove(HsinFu)
> Subject: Re: [alsa-devel] [PATCH v2] ASoC: rt5670: add set_bclk_ratio in dai ops
> 
> On 9/12/17 3:12 AM, Bard Liao wrote:
> > We need to set a specific bit for 50 bclk rate. So add set_bclk_ratio
> > function to set the bit.
> 
> When is this supposed to be used? the cht_bsw_rt5672 machine driver uses
> a 19.2MHz MCLK/2.4 MHz bclk, so there's a typical 50x ratio.

I think it should be used for all Intel platform. The bit will only be
effective in PCM mode with TDM enabled. It will influence the data
allocation format.
0: the dummy bits will be allocate at the end of each slot.
1: the dummy bits will be allocate at the end of all slots.
For example, 50fs with 24 bits data length.
0: 24 bits slot0 data + 1 dummy bit + 24 bits slot1 data + 1 dummy bit
1: 24 bits slot0 data + 24 bits slot1 data + 2 dummy bits

I will do slight modification on the patch since the bit should be set for
all bclk rate which is divisible by 50.

> 
> >
> > Signed-off-by: Bard Liao <bardliao at realtek.com>
> > ---
> > v2:
> > * add define for tdm data format select bit.
> > ---
> >   sound/soc/codecs/rt5670.c | 19 +++++++++++++++++++
> >   sound/soc/codecs/rt5670.h |  4 ++++
> >   2 files changed, 23 insertions(+)
> >
> > diff --git a/sound/soc/codecs/rt5670.c b/sound/soc/codecs/rt5670.c
> > index 9545764..da7614c 100644
> > --- a/sound/soc/codecs/rt5670.c
> > +++ b/sound/soc/codecs/rt5670.c
> > @@ -2582,6 +2582,24 @@ static int rt5670_set_tdm_slot(struct snd_soc_dai
> *dai, unsigned int tx_mask,
> >   	return 0;
> >   }
> >
> > +static int rt5670_set_bclk_ratio(struct snd_soc_dai *dai, unsigned int ratio)
> > +{
> > +	struct snd_soc_codec *codec = dai->codec;
> > +
> > +	dev_dbg(codec->dev, "%s ratio=%d\n", __func__, ratio);
> > +	if (dai->id != RT5670_AIF1)
> > +		return 0;
> > +
> > +	if (ratio == 50)
> > +		snd_soc_update_bits(codec, RT5670_GEN_CTRL3,
> > +			RT5670_TDM_DATA_MODE_SEL,
> RT5670_TDM_DATA_MODE_50FS);
> > +	else
> > +		snd_soc_update_bits(codec, RT5670_GEN_CTRL3,
> > +			RT5670_TDM_DATA_MODE_SEL,
> RT5670_TDM_DATA_MODE_NOR);
> > +
> > +	return 0;
> > +}
> > +
> >   static int rt5670_set_bias_level(struct snd_soc_codec *codec,
> >   			enum snd_soc_bias_level level)
> >   {
> > @@ -2712,6 +2730,7 @@ static const struct snd_soc_dai_ops
> rt5670_aif_dai_ops = {
> >   	.set_fmt = rt5670_set_dai_fmt,
> >   	.set_tdm_slot = rt5670_set_tdm_slot,
> >   	.set_pll = rt5670_set_dai_pll,
> > +	.set_bclk_ratio = rt5670_set_bclk_ratio,
> >   };
> >
> >   static struct snd_soc_dai_driver rt5670_dai[] = {
> > diff --git a/sound/soc/codecs/rt5670.h b/sound/soc/codecs/rt5670.h
> > index 5ba485c..265df80 100644
> > --- a/sound/soc/codecs/rt5670.h
> > +++ b/sound/soc/codecs/rt5670.h
> > @@ -1816,6 +1816,10 @@
> >   #define RT5670_ZCD_HP_DIS			(0x0 << 15)
> >   #define RT5670_ZCD_HP_EN			(0x1 << 15)
> >
> > +/* General Control 3 (0xfc) */
> > +#define RT5670_TDM_DATA_MODE_SEL		(0x1 << 11)
> > +#define RT5670_TDM_DATA_MODE_NOR		(0x0 << 11)
> > +#define RT5670_TDM_DATA_MODE_50FS		(0x1 << 11)
> >
> >   /* Codec Private Register definition */
> >   /* 3D Speaker Control (0x63) */
> >
> 
> 
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