Re: [PATCH v2 1/2] ASoC: dt-bindings: nau8821: Add DMIC slew rate selection

[Rob Herring <robh@kernel.org>]

On Fri, Oct 27, 2023 at 03:11:35PM +0100, Conor Dooley wrote:
> Hey,
> 
> On Fri, Oct 27, 2023 at 04:21:43PM +0800, Seven Lee wrote:
> > Add input with DMIC slew rate selection
> > 
> > Signed-off-by: Seven Lee <wtli@nuvoton.com>
> > ---
> >  .../devicetree/bindings/sound/nuvoton,nau8821.yaml        | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/sound/nuvoton,nau8821.yaml b/Documentation/devicetree/bindings/sound/nuvoton,nau8821.yaml
> > index 3e54abd4ca74..01028b7ff85c 100644
> > --- a/Documentation/devicetree/bindings/sound/nuvoton,nau8821.yaml
> > +++ b/Documentation/devicetree/bindings/sound/nuvoton,nau8821.yaml
> > @@ -89,6 +89,13 @@ properties:
> >      $ref: /schemas/types.yaml#/definitions/uint32
> >      default: 3072000
> >  
> > +  nuvoton,dmic-slew-rate-selection:
> > +    description: the number from 0 to 7 that sets the DMIC slew rate.
> > +        The unit is mV/ns. 0 is the slowest, and 7 is the fastest.
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    maximum: 7
> > +    default: 0
> 
> I meant make the property in terms of the unit, so
> nuvoton,dmic-slew-rate-volt-per-sec (or similar, Rob would likely know
> better how he likes the unit suffix for a more complex unit like this
> one) and then make it an enum with possible values corresponding to
> the real values that putting 0, 1, 2, 3 etc into the register produces.

From what I've seen, you often don't know what units the h/w settings 
correspond to. Often it's just fast, medium, slow or something. And 
here, 0 doesn't make sense if the units really are mV/ns. 

So I'd just drop '-selection' and be done with it. (And clear up the 
units part).

> 
> Cheers,
> Conor.
> 
> > +
> >    nuvoton,left-input-single-end:
> >      description: Enable left input with single-ended settings if set.
> >          For the headset mic application, the single-ended control is
> > @@ -127,6 +134,7 @@ examples:
> >              nuvoton,jack-insert-debounce = <7>;
> >              nuvoton,jack-eject-debounce = <0>;
> >              nuvoton,dmic-clk-threshold = <3072000>;
> > +            nuvoton,dmic-slew-rate-selection= <0>;
> >              #sound-dai-cells = <0>;
> >          };
> >      };
> > -- 
> > 2.25.1
> >