Re: [PATCH RFC v2 2/6] ASoC: dt-bindings: qcom,sm8250: Add clocks properties for I2S

[Neil Armstrong]

On 10/9/25 16:29, Srinivas Kandagatla wrote:
> On 10/9/25 3:25 PM, Neil Armstrong wrote:
> > On 10/9/25 16:06, Srinivas Kandagatla wrote:
> > > On 10/9/25 3:03 PM, Neil Armstrong wrote:
> > > > On 10/9/25 15:36, Srinivas Kandagatla wrote:
> > > > > On 10/8/25 7:56 PM, Neil Armstrong wrote:
> > > > > > In order to describe the block and master clock of each I2S bus, add
> > > > > > the first 5 I2S busses clock entries.
> > > > > >
> > > > > > The names (primary, secondary, tertiarty, quaternary, quinary, senary)
> > > > > > uses the LPASS clock naming which were used for a long time on
> > > > > > Qualcomm
> > > > > > LPASS firmware interfaces.
> > > > > >
> > > > > > Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> > > > > > ---
> > > > > >     .../devicetree/bindings/sound/qcom,sm8250.yaml      | 21 ++++++++++
> > > > > > +++++++++++
> > > > > >     1 file changed, 21 insertions(+)
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/sound/qcom,sm8250.yaml
> > > > > > b/Documentation/devicetree/bindings/sound/qcom,sm8250.yaml
> > > > > > index
> > > > > > 8ac91625dce5ccba5c5f31748c36296b12fac1a6..d1420d138b7ed8152aa53769c4d495e1674275e6 100644
> > > > > > --- a/Documentation/devicetree/bindings/sound/qcom,sm8250.yaml
> > > > > > +++ b/Documentation/devicetree/bindings/sound/qcom,sm8250.yaml
> > > > > > @@ -64,6 +64,27 @@ properties:
> > > > > >         $ref: /schemas/types.yaml#/definitions/string
> > > > > >         description: User visible long sound card name
> > > > > >     +  clocks:
> > > > > > +    minItems: 2
> > > > > > +    maxItems: 12
> > > > > > +
> > > > > > +  clock-names:
> > > > > > +    minItems: 2
> > > > > > +    items:
> > > > > > +      # mclk is the I2S Master Clock, mi2s the I2S Bit Clock
> > > > > > +      - const: primary-mi2s
> > > > > > +      - const: primary-mclk
> > > > > > +      - const: secondary-mi2s
> > > > > > +      - const: secondary-mclk
> > > > > > +      - const: tertiary-mi2s
> > > > > > +      - const: tertiary-mclk
> > > > > > +      - const: quaternary-mi2s
> > > > > > +      - const: quaternary-mclk
> > > > > > +      - const: quinary-mi2s
> > > > > > +      - const: quinary-mclk
> > > > > > +      - const: senary-mi2s
> > > > > > +      - const: senary-mclk
> > > > > > +
> > > > >
> > > > > I don't this is correct way to handling bitclk and mclks for I2S, these
> > > > > are normally handled as part of snd_soc_dai_set_sysclk() transparently
> > > > > without need of any device tree description.
> > > > >
> > > > > Also doing this way is an issue as this is going to break existing
> > > > > Elite
> > > > > based platforms, and the device description should not change across
> > > > > these both audio firmwares.
> > > >
> > > > This is only for AudioReach platforms, on those platforms the
> > > > clocks are registered in DT and are not accessible by the card.
> > > Clocks will be acessable via snd_soc_dai_set_sysclk ->
> > > q6prm_set_lpass_clock once set_sysclk support is added to q6apm-lpass
> > > i2s dai ops.
> > >
> > >
> > > > Device description is obviously different for the AudioReach platforms.
> > >
> > > Why should it be different, its same device.
> > > We have platforms that use both Elite and Audioreach.
> >
> > I'm perfectly aware of that, it's the case for sc7280/qcm6490. And I agree
> > the card bindings is the same, but it doesn't mean the DSP elements are the
> > same and uses in the same manner.
> >
> > So let's forget the bindings and forget those clocks entries, and imagine
> > I'll implement those _sys_sysclk calls like for the Elite platforms.
> > This means I'll bypass the clock framework by directly setting the PRM
> > clocks, this is clearly a layer violation.
>
> You can claim clocks in the dsp layer (q6apm-lpass-dais) instead of
> claiming it in machine layer, it does not necessarily have to bypass the
> clk framework.

The current q6afe implementation totally bypasses the clock framework:

static int q6afe_set_lpass_clock_v2(struct q6afe_port *port,
				 struct afe_clk_set *cfg)
{
	return q6afe_port_set_param(port, cfg, AFE_PARAM_ID_CLOCK_SET,
				    AFE_MODULE_CLOCK_SET, sizeof(*cfg));
}

I have no time right now to implement all that for q6apm & q6prm in the
way you propose, so I'll probably not send a new version.

Neil

> --srini
> > Neil
> >
> > > --srini
> > > > Neil
> > > >
> > > > > thanks,
> > > > > Srini
> > > > >
> > > > > >     patternProperties:
> > > > > >       ".*-dai-link$":
> > > > > >         description: