Re: [PATCH 20/21] ASoC: sun4i-i2s: Add support for TDM slots

[Sergey Suloev]

Hi, Maxime,

On 8/21/19 3:05 PM, Maxime Ripard wrote:
> Hi,
>
> On Tue, Aug 20, 2019 at 08:46:30AM +0300, Sergey Suloev wrote:
> > Hi, Maxime,
> >
> > On 8/19/19 10:25 PM, Maxime Ripard wrote:
> > > From: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
> > >
> > > The i2s controller supports TDM, for up to 8 slots. Let's support the TDM
> > > API.
> > >
> > > Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
> > > ---
> > >    sound/soc/sunxi/sun4i-i2s.c | 40 ++++++++++++++++++++++++++++++++------
> > >    1 file changed, 34 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> > > index 0dac09814b65..4f76daeaaed7 100644
> > > --- a/sound/soc/sunxi/sun4i-i2s.c
> > > +++ b/sound/soc/sunxi/sun4i-i2s.c
> > > @@ -168,6 +168,8 @@ struct sun4i_i2s {
> > >    	struct reset_control *rst;
> > >    	unsigned int	mclk_freq;
> > > +	unsigned int	slots;
> > > +	unsigned int	slot_width;
> > >    	struct snd_dmaengine_dai_dma_data	capture_dma_data;
> > >    	struct snd_dmaengine_dai_dma_data	playback_dma_data;
> > > @@ -287,7 +289,7 @@ static bool sun4i_i2s_oversample_is_valid(unsigned int oversample)
> > >    static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
> > >    				  unsigned int rate,
> > > -				  unsigned int channels,
> > > +				  unsigned int slots,
> > >    				  unsigned int word_size)
> > >    {
> > >    	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
> > > @@ -335,7 +337,7 @@ static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
> > >    	bclk_parent_rate = i2s->variant->get_bclk_parent_rate(i2s);
> > >    	bclk_div = sun4i_i2s_get_bclk_div(i2s, bclk_parent_rate,
> > > -					  rate, channels, word_size);
> > > +					  rate, slots, word_size);
> > >    	if (bclk_div < 0) {
> > >    		dev_err(dai->dev, "Unsupported BCLK divider: %d\n", bclk_div);
> > >    		return -EINVAL;
> > > @@ -419,6 +421,10 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> > >    				  const struct snd_pcm_hw_params *params)
> > >    {
> > >    	unsigned int channels = params_channels(params);
> > > +	unsigned int slots = channels;
> > > +
> > > +	if (i2s->slots)
> > > +		slots = i2s->slots;
> > >    	/* Map the channels for playback and capture */
> > >    	regmap_write(i2s->regmap, SUN8I_I2S_TX_CHAN_MAP_REG, 0x76543210);
> > > @@ -428,7 +434,6 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> > >    	regmap_update_bits(i2s->regmap, SUN8I_I2S_TX_CHAN_SEL_REG,
> > >    			   SUN4I_I2S_CHAN_SEL_MASK,
> > >    			   SUN4I_I2S_CHAN_SEL(channels));
> > > -
> > >    	regmap_update_bits(i2s->regmap, SUN8I_I2S_RX_CHAN_SEL_REG,
> > >    			   SUN4I_I2S_CHAN_SEL_MASK,
> > >    			   SUN4I_I2S_CHAN_SEL(channels));
> > > @@ -452,10 +457,18 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
> > >    			       struct snd_soc_dai *dai)
> > >    {
> > >    	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
> > > +	unsigned int word_size = params_width(params);
> > >    	unsigned int channels = params_channels(params);
> > > +	unsigned int slots = channels;
> > >    	int ret, sr, wss;
> > >    	u32 width;
> > > +	if (i2s->slots)
> > > +		slots = i2s->slots;
> > > +
> > > +	if (i2s->slot_width)
> > > +		word_size = i2s->slot_width;
> > > +
> > >    	ret = i2s->variant->set_chan_cfg(i2s, params);
> > >    	if (ret < 0) {
> > >    		dev_err(dai->dev, "Invalid channel configuration\n");
> > > @@ -477,15 +490,14 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
> > >    	if (sr < 0)
> > >    		return -EINVAL;
> > > -	wss = i2s->variant->get_wss(i2s, params_width(params));
> > > +	wss = i2s->variant->get_wss(i2s, word_size);
> > >    	if (wss < 0)
> > >    		return -EINVAL;
> > >    	regmap_field_write(i2s->field_fmt_wss, wss);
> > >    	regmap_field_write(i2s->field_fmt_sr, sr);
> > > -	return sun4i_i2s_set_clk_rate(dai, params_rate(params),
> > > -				      channels, params_width(params));
> > > +	return sun4i_i2s_set_clk_rate(dai, params_rate(params), slots, word_size);
> > >    }
> > >    static int sun4i_i2s_set_soc_fmt(const struct sun4i_i2s *i2s,
> > > @@ -785,10 +797,26 @@ static int sun4i_i2s_set_sysclk(struct snd_soc_dai *dai, int clk_id,
> > >    	return 0;
> > >    }
> > > +static int sun4i_i2s_set_tdm_slot(struct snd_soc_dai *dai,
> > > +				  unsigned int tx_mask, unsigned int rx_mask,
> > > +				  int slots, int slot_width)
> > > +{
> > > +	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
> > > +
> > > +	if (slots > 8)
> > > +		return -EINVAL;
> > > +
> > > +	i2s->slots = slots;
> > > +	i2s->slot_width = slot_width;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > >    static const struct snd_soc_dai_ops sun4i_i2s_dai_ops = {
> > >    	.hw_params	= sun4i_i2s_hw_params,
> > >    	.set_fmt	= sun4i_i2s_set_fmt,
> > >    	.set_sysclk	= sun4i_i2s_set_sysclk,
> > > +	.set_tdm_slot	= sun4i_i2s_set_tdm_slot,
> > >    	.trigger	= sun4i_i2s_trigger,
> > >    };
> > it seems like you forgot to implement sun4i_i2s_dai_ops.set_bclk_ratio
> > because, as I far as I understand, it should alter tdm slots functionality
> > indirectly.
> As far as I can see, while this indeed changes a few things on the TDM
> setup, it's optional, orthogonal and it has a single user in the tree
> (some intel platform card).
>
> So I'd say that if someone ever needs it, we can have it, but it's not
> a blocker.

"orthogonal" meaning that one can achieve the same effect with using 
"sun4i_i2s_set_tdm_slot" instead of "set_bclk_ratio" ?

For example, for WM8731 codec in "non-USB" master mode should generate 
BCLK = 64 * FS, and I had to implement "set_bclk_ratio" in order to 
setup it. Note, that this is 100% mandatory condition for the code to 
operate in this mode.

Did you mean that now the correct way would be using 
"sun4i_i2s_set_tdm_slot" instead ?


Thank you


> Maxime
>
> --
> Maxime Ripard, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com