Re: [PATCH v4 1/2] dt-bindings: iio: adc: Add Nuvoton MA35D1 EADC

[Chi-Wen Weng]

Rob Herring 於 2026/11/11 上午 03:08 寫道:
> On Wed, Nov 04, 2026 at 05:11:35PM +0800, Chi-Wen Weng wrote:
> > From: Chi-Wen Weng <cwweng@xxxxxxxxxxx>
> >
> > Add a binding for the Enhanced Analog-to-Digital Converter found on
> > Nuvoton MA35D1 SoCs.
> >
> > The controller has eight external analog inputs. They can be used as
> > single-ended inputs or as the four fixed differential pairs 0-4, 1-5,
> > 2-6 and 3-7.
> >
> > Use the common ADC channel properties to describe the physical input
> > independently of the logical channel index.
> >
> > Signed-off-by: Chi-Wen Weng <cwweng@xxxxxxxxxxx>
> > ---
> >   .../bindings/iio/adc/nuvoton,ma35d1-eadc.yaml | 163 ++++++++++++++++++
> >   1 file changed, 163 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml b/Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml
> > new file mode 100644
> > index 000000000000..85b0feac0236
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml
> > @@ -0,0 +1,163 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/nuvoton,ma35d1-eadc.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Nuvoton MA35D1 Enhanced Analog-to-Digital Converter
> > +
> > +maintainers:
> > +  - Chi-Wen Weng <cwweng@xxxxxxxxxxx>
> > +
> > +description: |
> > +  The Nuvoton MA35D1 Enhanced Analog-to-Digital Converter (EADC) is a
> > +  12-bit successive approximation converter with eight external analog
> > +  inputs and one internally connected VBAT input.
> > +
> > +  The external inputs can be used as eight single-ended channels or as
> > +  four fixed differential pairs: 0-4, 1-5, 2-6 and 3-7. The internally
> > +  connected VBAT input is not described by a channel child node.
> > +
> > +  The controller provides four interrupt outputs, ADINT0 through ADINT3.
> > +
> > +properties:
> > +  compatible:
> > +    const: nuvoton,ma35d1-eadc
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    items:
> > +      - description: ADINT0
> > +      - description: ADINT1
> > +      - description: ADINT2
> > +      - description: ADINT3
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  resets:
> > +    maxItems: 1
> > +
> > +  vref-supply:
> > +    description:
> > +      Optional external reference voltage connected to the VREF pin. If this
> > +      supply is absent, the controller uses its internal 1.6 V reference.
> > +
> > +  dmas:
> > +    maxItems: 1
> > +
> > +  dma-names:
> > +    const: rx
> > +
> > +  '#io-channel-cells':
> > +    const: 1
> > +    description:
> > +      The cell selects the logical EADC channel identified by the reg value
> > +      of the corresponding channel child node.
> > +
> > +  '#address-cells':
> > +    const: 1
> > +
> > +  '#size-cells':
> > +    const: 0
> > +
> > +patternProperties:
> > +  '^channel@[0-7]$':
> > +    type: object
> > +    $ref: /schemas/iio/adc/adc.yaml#
> > +    description: |
> > +      External EADC channel description. The reg property identifies the
> > +      logical IIO channel index.
> > +
> > +      A single-ended channel may use single-channel to select an external
> > +      analog input independently of reg. If single-channel and diff-channels
> > +      are both absent, the external analog input is selected by reg.
> > +
> > +      A differential channel uses diff-channels to select one of the fixed
> > +      hardware input pairs: 0-4, 1-5, 2-6 or 3-7. Each single-ended input
> > +      and each differential input pair may be described at most once.
> > +
> > +    properties:
> > +      reg:
> > +        maximum: 7
> > +
> > +      single-channel:
> > +        maximum: 7
> > +
> > +      diff-channels:
> > +        oneOf:
> > +          - items:
> > +              - const: 0
> > +              - const: 4
> > +          - items:
> > +              - const: 1
> > +              - const: 5
> > +          - items:
> > +              - const: 2
> > +              - const: 6
> > +          - items:
> > +              - const: 3
> > +              - const: 7
> > +
> > +    allOf:
> > +      - not:
> > +          required:
> > +            - single-channel
> > +            - diff-channels
> > +
> > +    required:
> > +      - reg
>
> The allOf and required are effectively covered by adc.yaml already.
>
> Rob

Hi Rob,

> The allOf and required are effectively covered by adc.yaml already.

The channel-level required list is redundant; I'll remove it.

For the allOf, adc.yaml currently has:

anyOf:
  - oneOf:
      - required:
          - reg
          - diff-channels
      - required:
          - reg
          - single-channel
  - required:
      - reg

When both single-channel and diff-channels are present, the inner
oneOf fails, but the reg-only branch still satisfies the outer anyOf.
Removing the local constraint would therefore allow both properties
together, which the driver rejects.

Should I keep the local check, or move the mutual-exclusion constraint
into adc.yaml?

Thanks,
Chi-Wen