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SubjectRe: [PATCH v5 02/15] ASoC: sun4i-i2s: Add set_tdm_slot functionality
On Wed, 14 Aug 2019 at 13:08, Maxime Ripard <maxime.ripard@bootlin.com> wrote:
>
> Hi,
>
> On Wed, Aug 14, 2019 at 08:08:41AM +0200, codekipper@gmail.com wrote:
> > From: Marcus Cooper <codekipper@gmail.com>
> >
> > Codecs without a control connection such as i2s based HDMI audio and
> > the Pine64 DAC require a different amount of bit clocks per frame than
> > what is calculated by the sample width. Use the tdm slot bindings to
> > provide this mechanism.
> >
> > Signed-off-by: Marcus Cooper <codekipper@gmail.com>
> > ---
> > sound/soc/sunxi/sun4i-i2s.c | 23 +++++++++++++++++++++--
> > 1 file changed, 21 insertions(+), 2 deletions(-)
> >
> > diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> > index 8201334a059b..7c37b6291df0 100644
> > --- a/sound/soc/sunxi/sun4i-i2s.c
> > +++ b/sound/soc/sunxi/sun4i-i2s.c
> > @@ -195,6 +195,9 @@ struct sun4i_i2s {
> > struct regmap_field *field_rxchansel;
> >
> > const struct sun4i_i2s_quirks *variant;
> > +
> > + unsigned int tdm_slots;
> > + unsigned int slot_width;
> > };
> >
> > struct sun4i_i2s_clk_div {
> > @@ -346,7 +349,7 @@ static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
> > if (i2s->variant->has_fmt_set_lrck_period)
> > regmap_update_bits(i2s->regmap, SUN4I_I2S_FMT0_REG,
> > SUN8I_I2S_FMT0_LRCK_PERIOD_MASK,
> > - SUN8I_I2S_FMT0_LRCK_PERIOD(32));
> > + SUN8I_I2S_FMT0_LRCK_PERIOD(word_size));
> >
> >
> > /* Set sign extension to pad out LSB with 0 */
> > regmap_field_write(i2s->field_fmt_sext, 0);
> > @@ -450,7 +453,8 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
> > regmap_field_write(i2s->field_fmt_sr, sr);
> >
> > return sun4i_i2s_set_clk_rate(dai, params_rate(params),
> > - params_width(params));
> > + i2s->tdm_slots ?
> > + i2s->slot_width : params_width(params));
>
> This is slightly more complicated than that.

At this point we're only supporting 2 channels with fixed slot
settings. I've added a comment to state
that we're using the tdm_slot at the moment as an indicator to
override the slot width. Do you think
that is enough for now?.

Thanks,
CK
>
> On the H3 (and all related ones), the CHAN_CFG_TX_SLOT_NUM and
> _RX_SLOT_NUM fields in the CHAN_CFG register need to be set to the
> number of slots as well.
>
> Maxime
>
> --
> Maxime Ripard, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com

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