Re: [PATCH v10 2/6] dt-bindings: opp: v2-qcom-level: Document CPR3 open/closed loop volt adjustment

[AngeloGioacchino Del Regno]

Il 18/02/23 01:26, Konrad Dybcio ha scritto:
> On 18.02.2023 00:13, Rob Herring wrote:
> > On Fri, Feb 17, 2023 at 12:08:25PM +0100, Konrad Dybcio wrote:
> > > CPR3 and newer can be fed per-OPP voltage adjustment values for both
> > > open- and closed-loop paths to make better decisions about settling
> > > on the final voltage offset target. Document these properties.
> > >
> > > Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> > > ---
> > >   .../devicetree/bindings/opp/opp-v2-qcom-level.yaml         | 14 ++++++++++++++
> > >   1 file changed, 14 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/opp/opp-v2-qcom-level.yaml b/Documentation/devicetree/bindings/opp/opp-v2-qcom-level.yaml
> > > index a30ef93213c0..93cc88434dfe 100644
> > > --- a/Documentation/devicetree/bindings/opp/opp-v2-qcom-level.yaml
> > > +++ b/Documentation/devicetree/bindings/opp/opp-v2-qcom-level.yaml
> > > @@ -34,6 +34,20 @@ patternProperties:
> > >           minItems: 1
> > >           maxItems: 2
> > >   
> > > +      qcom,opp-cloop-vadj:
> > > +        description: |
> > > +          A value representing the closed-loop voltage adjustment value
> >
> > A value?
> >
> > > +          associated with this OPP node.
> > > +        $ref: /schemas/types.yaml#/definitions/int32-array
> > > +        maxItems: 2
> >
> > Or 2 values?
> Right, this description doesn't make any sense if you're just
> looking at the documentation without looking at the driver..
>
> Generally, each CPR3 instance can have multiple "threads"
> (each one of which regulates voltage for some on-SoC IP or
> part of it). The nth entry in the qcom,opp-[co]loop-vadj
> array corresponds to a voltage offset for the nth thread.
>
> If the nth entry in the array is missing, the driver assumes
> the arr[0] one is "global" to this CPR3 instance at this OPP
> level and applies it to all threads. ...and looking at it
> again, this is sorta just bad design, especially if you
> take into account that there's no known user of CPR3 that
> employs more than 2 threads.
>
> I'll remove that from the driver and make the description clearer.

description:
  Represents the closed-loop voltage adjustment associated with
  this OPP node.

P.S.: Drop '|' here and on oloop!

This binding is intended to support either single or multiple CPR threads;
the driver's behavior is unimportant as bindings describe the hardware,
not the driver.

Regards,
Angelo

> Also, only noticed now.. "qcom,sdm630-cprh" was not documented,
> so that's to be fixed for the next submission as well!
>
>
> Konrad
> > > +
> > > +      qcom,opp-oloop-vadj:
> > > +        description: |
> > > +          A value representing the open-loop voltage adjustment value
> > > +          associated with this OPP node.
> > > +        $ref: /schemas/types.yaml#/definitions/int32-array
> > > +        maxItems: 2
> > > +
> > >       required:
> > >         - opp-level
> > >         - qcom,opp-fuse-level
> > >
> > > --
> > > 2.39.1