Re: [PATCH 1/4] dt-bindings: Add Raspberry Pi's RP1 ADC

Guenter Roeck
2025-09-25T20:37:36Z

On Thu, Sep 25, 2025 at 08:40:54PM +0100, Conor Dooley wrote:
> On Thu, Sep 25, 2025 at 03:04:13AM +0300, Stanimir Varbanov wrote:
> > Document dt-bindings for Raspberry Pi's RP1 ADC.
> >
> > Signed-off-by: Stanimir Varbanov <svarbanov@suse.de>
> > ---
> > .../bindings/hwmon/raspberrypi,rp1-adc.yaml | 46 +++++++++++++++++++
> > 1 file changed, 46 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/hwmon/raspberrypi,rp1-adc.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/hwmon/raspberrypi,rp1-adc.yaml b/Documentation/devicetree/bindings/hwmon/raspberrypi,rp1-adc.yaml
> > new file mode 100644
> > index 000000000000..5266b253fd2b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/hwmon/raspberrypi,rp1-adc.yaml
> > @@ -0,0 +1,46 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/hwmon/raspberrypi,rp1-adc.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Rasberry Pi RP1 ADC device
> > +
> > +maintainers:
> > + - Stanimir Varbanov <svarbanov@suse.de>
> > +
> > +description: |
> > + The RP1 ADC is a five input successive-approximation ADC with 12-bit
> > + resolution (ENOB 9.5-bit) at 500kSPS. It has four external inputs
> > + and one internal temperature sensor.
> > +
> > +properties:
> > + compatible:
> > + const: raspberrypi,rp1-adc
> > +
> > + reg:
> > + maxItems: 1
> > +
> > + clocks:
> > + maxItems: 1
> > +
> > + vref-supply:
> > + description:
> > + Reference voltage regulator 3.3V.
>
> Looks like you're missing the io-channels-cells property that allows
> this device to be a provider of adc channels to other devices.
>
Only makes sense if the driver is implemented as iio driver.
Which would be fine with me, assuming this is a generic ADC.
The iio -> hwmon bridge can then be used to instantiate a
hwmon device if needed.

Guenter