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

[David Lechner]

On 6/25/26 6:06 AM, Chi-Wen Weng wrote:
> From: Chi-Wen Weng <cwweng@xxxxxxxxxxx>
> 
> Add devicetree binding for the Enhanced ADC controller found on
> Nuvoton MA35D1 SoCs.
> 
> The controller has one register region, one interrupt and one functional
> clock. ADC inputs are described using standard channel child nodes,
> including optional differential channel pairs.
> 
> Signed-off-by: Chi-Wen Weng <cwweng@xxxxxxxxxxx>
> ---
>  .../bindings/iio/adc/nuvoton,ma35d1-eadc.yaml | 100 ++++++++++++++++++
>  1 file changed, 100 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..ae7ad0f7689a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml
> @@ -0,0 +1,100 @@
> +# 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 ADC controller integrated in the MA35D1 SoC. Each enabled ADC
> +  input is described by a child channel node.
> +
> +properties:
> +  compatible:
> +    const: nuvoton,ma35d1-eadc
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1

Datasheet says there are 4 interrupts.

> +
> +  clocks:
> +    maxItems: 1

Should there be an optional vref-supply for the V_REF pin?

Should there be a dmas property? Datasheet says it supports
PDMA transfer.

> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +patternProperties:
> +  '^channel@[0-8]$':
> +    type: object
> +    $ref: adc.yaml
> +    unevaluatedProperties: false
> +
> +    properties:
> +      reg:
> +        minimum: 0
> +        maximum: 8

I assume 8 is for the internal batter voltage channel? Often, we don't
include fixed internal channels like this in the devicetree since they
are always the same and don't depend on external wiring.

> +
> +      diff-channels:
> +        minItems: 2
> +        maxItems: 2

adc.yaml already specifies minItems and maxItems, so we don't need to repeat it.

> +        items:
> +          minimum: 0
> +          maximum: 8

This (and reg) are uint32, so don't really need minimum: 0.

Also, I assume that 8 is for the internal battery voltage channel, which
wouldn't make sense as part of a differential input.

> +
> +    required:
> +      - reg
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - '#address-cells'
> +  - '#size-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/nuvoton,ma35d1-clk.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        adc@40430000 {
> +            compatible = "nuvoton,ma35d1-eadc";
> +            reg = <0x0 0x40430000 0x0 0x10000>;
> +            interrupts = <GIC_SPI 65 IRQ_TYPE_LEVEL_HIGH>;
> +            clocks = <&clk EADC_GATE>;
> +
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            channel@0 {
> +                reg = <0>;
> +            };
> +
> +            channel@1 {
> +                reg = <1>;
> +            };
> +
> +            channel@2 {
> +                reg = <2>;
> +                diff-channels = <2 3>;
> +            };
> +        };
> +    };
> +...