Re: [PATCH v6 02/14] ASoC: sun4i-i2s: Change set_chan_cfg() params

[Maxime Ripard]

Hi Samuel,

On Mon, Oct 12, 2020 at 08:15:30PM -0500, Samuel Holland wrote:
> On 10/12/20 7:15 AM, Maxime Ripard wrote:
> > Hi,
> > 
> > On Mon, Oct 05, 2020 at 03:23:12PM +0200, Clément Péron wrote:
> >> On Mon, 5 Oct 2020 at 14:13, Maxime Ripard <maxime@xxxxxxxxxx> wrote:
> >>>
> >>> On Sat, Oct 03, 2020 at 04:19:38PM +0200, Clément Péron wrote:
> >>>> As slots and slot_width can be set manually using set_tdm().
> >>>> These values are then kept in sun4i_i2s struct.
> >>>> So we need to check if these values are setted or not
> >>>> in the struct.
> >>>>
> >>>> Avoid to check for this logic in set_chan_cfg(). This will
> >>>> duplicate the same check instead pass the required values
> >>>> as params to set_chan_cfg().
> >>>>
> >>>> This will also avoid a bug when we will enable 20/24bits support,
> >>>> i2s->slot_width is not actually used in the lrck_period computation.
> >>>>
> >>>> Suggested-by: Samuel Holland <samuel@xxxxxxxxxxxx>
> >>>> Signed-off-by: Clément Péron <peron.clem@xxxxxxxxx>
> >>>> ---
> >>>>  sound/soc/sunxi/sun4i-i2s.c | 36 ++++++++++++++----------------------
> >>>>  1 file changed, 14 insertions(+), 22 deletions(-)
> >>>>
> >>>> diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> >>>> index c5ccd423e6d3..1f577dbc20a6 100644
> >>>> --- a/sound/soc/sunxi/sun4i-i2s.c
> >>>> +++ b/sound/soc/sunxi/sun4i-i2s.c
> >>>> @@ -177,8 +177,9 @@ struct sun4i_i2s_quirks {
> >>>>       unsigned long (*get_bclk_parent_rate)(const struct sun4i_i2s *);
> >>>>       s8      (*get_sr)(const struct sun4i_i2s *, int);
> >>>>       s8      (*get_wss)(const struct sun4i_i2s *, int);
> >>>> -     int     (*set_chan_cfg)(const struct sun4i_i2s *,
> >>>> -                             const struct snd_pcm_hw_params *);
> >>>> +     int     (*set_chan_cfg)(const struct sun4i_i2s *i2s,
> >>>> +                             unsigned int channels,  unsigned int slots,
> >>>> +                             unsigned int slot_width);
> >>>>       int     (*set_fmt)(const struct sun4i_i2s *, unsigned int);
> >>>>  };
> >>>>
> >>>> @@ -414,10 +415,9 @@ static s8 sun8i_i2s_get_sr_wss(const struct sun4i_i2s *i2s, int width)
> >>>>  }
> >>>>
> >>>>  static int sun4i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> >>>> -                               const struct snd_pcm_hw_params *params)
> >>>> +                               unsigned int channels, unsigned int slots,
> >>>> +                               unsigned int slot_width)
> >>>>  {
> >>>> -     unsigned int channels = params_channels(params);
> >>>> -
> >>>>       /* Map the channels for playback and capture */
> >>>>       regmap_write(i2s->regmap, SUN4I_I2S_TX_CHAN_MAP_REG, 0x76543210);
> >>>>       regmap_write(i2s->regmap, SUN4I_I2S_RX_CHAN_MAP_REG, 0x00003210);
> >>>> @@ -434,15 +434,11 @@ static int sun4i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> >>>>  }
> >>>>
> >>>>  static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> >>>> -                               const struct snd_pcm_hw_params *params)
> >>>> +                               unsigned int channels, unsigned int slots,
> >>>> +                               unsigned int slot_width)
> >>>>  {
> >>>> -     unsigned int channels = params_channels(params);
> >>>> -     unsigned int slots = channels;
> >>>>       unsigned int lrck_period;
> >>>>
> >>>> -     if (i2s->slots)
> >>>> -             slots = i2s->slots;
> >>>> -
> >>>>       /* Map the channels for playback and capture */
> >>>>       regmap_write(i2s->regmap, SUN8I_I2S_TX_CHAN_MAP_REG, 0x76543210);
> >>>>       regmap_write(i2s->regmap, SUN8I_I2S_RX_CHAN_MAP_REG, 0x76543210);
> >>>> @@ -467,11 +463,11 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> >>>>       case SND_SOC_DAIFMT_DSP_B:
> >>>>       case SND_SOC_DAIFMT_LEFT_J:
> >>>>       case SND_SOC_DAIFMT_RIGHT_J:
> >>>> -             lrck_period = params_physical_width(params) * slots;
> >>>> +             lrck_period = slot_width * slots;
> >>>>               break;
> >>>>
> >>>>       case SND_SOC_DAIFMT_I2S:
> >>>> -             lrck_period = params_physical_width(params);
> >>>> +             lrck_period = slot_width;
> >>>>               break;
> >>>>
> >>>>       default:
> >>>> @@ -490,15 +486,11 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> >>>>  }
> >>>>
> >>>>  static int sun50i_h6_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> >>>> -                                   const struct snd_pcm_hw_params *params)
> >>>> +                                   unsigned int channels, unsigned int slots,
> >>>> +                                   unsigned int slot_width)
> >>>>  {
> >>>> -     unsigned int channels = params_channels(params);
> >>>> -     unsigned int slots = channels;
> >>>>       unsigned int lrck_period;
> >>>>
> >>>> -     if (i2s->slots)
> >>>> -             slots = i2s->slots;
> >>>> -
> >>>>       /* Map the channels for playback and capture */
> >>>>       regmap_write(i2s->regmap, SUN50I_H6_I2S_TX_CHAN_MAP0_REG, 0xFEDCBA98);
> >>>>       regmap_write(i2s->regmap, SUN50I_H6_I2S_TX_CHAN_MAP1_REG, 0x76543210);
> >>>> @@ -525,11 +517,11 @@ static int sun50i_h6_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> >>>>       case SND_SOC_DAIFMT_DSP_B:
> >>>>       case SND_SOC_DAIFMT_LEFT_J:
> >>>>       case SND_SOC_DAIFMT_RIGHT_J:
> >>>> -             lrck_period = params_physical_width(params) * slots;
> >>>> +             lrck_period = slot_width * slots;
> >>>>               break;
> >>>>
> >>>>       case SND_SOC_DAIFMT_I2S:
> >>>> -             lrck_period = params_physical_width(params);
> >>>> +             lrck_period = slot_width;
> >>>>               break;
> >>>>
> >>>>       default:
> >>>> @@ -565,7 +557,7 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
> >>>>       if (i2s->slot_width)
> >>>>               slot_width = i2s->slot_width;
> >>>>
> >>>> -     ret = i2s->variant->set_chan_cfg(i2s, params);
> >>>> +     ret = i2s->variant->set_chan_cfg(i2s, channels, slots, slot_width);
> >>>
> >>> Isn't slots and slot_width set to 0 here ?
> >>
> >> No, there is still a check before calling the set_cfg function.
> >>
> >>   unsigned int slot_width = params_physical_width(params);
> >>   unsigned int channels = params_channels(params);
> >>   unsigned int slots = channels;
> >>
> >>   if (i2s->slots)
> >>   slots = i2s->slots;
> >>
> >>   if (i2s->slot_width)
> >>   slot_width = i2s->slot_width;
> >>
> >> ret = i2s->variant->set_chan_cfg(i2s, channels, slots, slot_width);
> >>
> >> So slot_width will be equal to params_physical_width(params);
> >> like before
> > 
> > Still, it's not obvious what slots and slot_width are going to be set to
> > in a non-TDM setup where that doesn't really make much sense.
> 
> My understanding is:
> 
> "slots" is channels per frame + padding slots, regardless of format.
> "slot_width" is bits per sample + padding bits, regardless of format.
> 
> Some formats may require or prohibit certain padding, but that has no
> effect on the definitions.
> 
> That seems clear to me? At least that's what I implemented (and you
> acked) in sun8i-codec.

Yeah I guess you're right. I'd still like at least a comment on top of
the function making that clear so that no-one's confused

Maxime

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