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

[Chi-Wen Weng <cwweng.linux@gmail.com>]

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@nuvoton.com>
>>
>> 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@nuvoton.com>
>> ---
>>   .../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@nuvoton.com>
>> +
>> +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