Re: [PATCH v3 1/2] dt-bindings: thermal: generic-adc: Add optional io-channel-cells property

[Lukasz Luba]

On 3/5/25 10:03, Svyatoslav Ryhel wrote:
> ср, 5 бер. 2025 р. о 12:00 Lukasz Luba <lukasz.luba@xxxxxxx> пише:
> > On 3/3/25 12:21, Svyatoslav Ryhel wrote:
> > > This implements a mechanism to derive temperature values from an existing ADC IIO
> > > channel, effectively creating a temperature IIO channel. This approach avoids adding
> > > a new sensor and its associated conversion table, while providing IIO-based temperature
> > > data for devices that may not utilize hwmon.
> > >
> > > Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> > > ---
> > >    .../devicetree/bindings/thermal/generic-adc-thermal.yaml      | 4 ++++
> > >    1 file changed, 4 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/thermal/generic-adc-thermal.yaml b/Documentation/devicetree/bindings/thermal/generic-adc-thermal.yaml
> > > index 12e6418dc24d..4bc2cff0593c 100644
> > > --- a/Documentation/devicetree/bindings/thermal/generic-adc-thermal.yaml
> > > +++ b/Documentation/devicetree/bindings/thermal/generic-adc-thermal.yaml
> > > @@ -30,6 +30,9 @@ properties:
> > >      io-channel-names:
> > >        const: sensor-channel
> > >
> > > +  '#io-channel-cells':
> > > +    const: 1
> > > +
> > >      temperature-lookup-table:
> > >        description: |
> > >          Lookup table to map the relation between ADC value and temperature.
> > > @@ -60,6 +63,7 @@ examples:
> > >            #thermal-sensor-cells = <0>;
> > >            io-channels = <&ads1015 1>;
> > >            io-channel-names = "sensor-channel";
> > > +        #io-channel-cells = <1>;
> > >            temperature-lookup-table = <
> > >                  (-40000) 2578
> > >                  (-39000) 2577
> >
> > Do we really need this change in the DT?
> > Won't the code in the thermal driver that registers a new iio device
> > would just be enough?
> >
> > I agree with Rob that it looks odd.
>
> Building tree will complain on missing cells property if you try to
> bind it. It is not in required category anyway.

Fair enough, then I will leave it to DT folks.

For me it's looks OK-ish, assuming you add this property with the
comment describing it like Rob asked.

UUIC it will always be only 1 channel - with that temperature,
so shouldn't harm much the design in DT.