Re: [PATCH 2/7] dt-bindings: iio: adc: document RZ/T2H and RZ/N2H ADC

[Conor Dooley <conor@kernel.org>]

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On Tue, Sep 23, 2025 at 07:05:16PM +0300, Cosmin Tanislav wrote:
> Document the A/D 12-Bit successive approximation converters found in the
> Renesas RZ/T2H (R9A09G077) and RZ/N2H (R9A09G087) SoCs.
> 
> RZ/T2H has two ADCs with 4 channels and one with 6.
> RZ/N2H has two ADCs with 4 channels and one with 15.
> 
> Signed-off-by: Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
> ---
>  .../iio/adc/renesas,r9a09g077-adc.yaml        | 170 ++++++++++++++++++
>  MAINTAINERS                                   |   7 +
>  2 files changed, 177 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/renesas,r9a09g077-adc.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/renesas,r9a09g077-adc.yaml b/Documentation/devicetree/bindings/iio/adc/renesas,r9a09g077-adc.yaml
> new file mode 100644
> index 000000000000..840108cd317e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/renesas,r9a09g077-adc.yaml
> @@ -0,0 +1,170 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/renesas,r9a09g077-adc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Renesas RZ/T2H / RZ/N2H ADC12
> +
> +maintainers:
> +  - Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
> +
> +description: |
> +  A/D Converter block is a successive approximation analog-to-digital converter
> +  with a 12-bit accuracy. Up to 15 analog input channels can be selected.
> +  Conversions can be performed in single or continuous mode. Result of the ADC
> +  is stored in a 16-bit data register corresponding to each channel.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - renesas,r9a09g077-adc # RZ/T2H
> +      - renesas,r9a09g087-adc # RZ/N2H
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    items:
> +      - description: A/D scan end interrupt
> +      - description: A/D scan end interrupt for Group B
> +      - description: A/D scan end interrupt for Group C
> +      - description: Window A compare match
> +      - description: Window B compare match
> +      - description: Compare match
> +      - description: Compare mismatch
> +
> +  interrupt-names:
> +    items:
> +      - const: adi
> +      - const: gbadi
> +      - const: gcadi
> +      - const: cmpai
> +      - const: cmpbi
> +      - const: wcmpm
> +      - const: wcmpum
> +
> +  clocks:
> +    items:
> +      - description: converter clock
> +      - description: peripheral clock
> +
> +  clock-names:
> +    items:
> +      - const: adclk
> +      - const: pclk
> +
> +  power-domains:
> +    maxItems: 1
> +
> +  renesas,max-channels:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Maximum number of channels supported by the ADC.
> +      RZ/T2H has two ADCs with 4 channels and one with 6 channels.
> +      RZ/N2H has two ADCs with 4 channels and one with 15 channels.

What is the point of this? Why do you need to know how many channels
there can be in the driver, isn't it enough to just figure out how many
child nodes you have?

> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +  "#io-channel-cells":
> +    const: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - clock-names
> +  - power-domains
> +  - renesas,max-channels

This should be after patternProperties.

> +
> +patternProperties:
> +  "^channel@[0-9a-e]$":
> +    $ref: adc.yaml
> +    type: object
> +    description: The external channels which are connected to the ADC.
> +
> +    properties:
> +      reg:
> +        description: The channel number.
> +        maximum: 14
> +
> +    required:
> +      - reg
> +

> +    additionalProperties: false

You don't include any properties other than reg from adc.yaml, and using
additionalProperties: false blocks their use. Is that intentional or
should this be unevaluatedProperties: false?

Cheers,
Conor.

> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: renesas,r9a09g077-adc
> +    then:
> +      properties:
> +        renesas,max-channels:
> +          enum: [4, 6]
> +
> +      patternProperties:
> +        "^channel@[6-9a-e]$": false
> +        "^channel@[0-5]$":
> +          properties:
> +            reg:
> +              maximum: 5
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - renesas,r9a09g087-adc
> +    then:
> +      properties:
> +        renesas,max-channels:
> +          enum: [4, 15]
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/renesas,r9a09g077-cpg-mssr.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    adc@80008000 {
> +      compatible = "renesas,r9a09g077-adc";
> +      reg = <0x80008000 0x400>;
> +      interrupts = <GIC_SPI 708 IRQ_TYPE_EDGE_RISING>,
> +                   <GIC_SPI 709 IRQ_TYPE_EDGE_RISING>,
> +                   <GIC_SPI 710 IRQ_TYPE_EDGE_RISING>,
> +                   <GIC_SPI 711 IRQ_TYPE_LEVEL_HIGH>,
> +                   <GIC_SPI 712 IRQ_TYPE_LEVEL_HIGH>,
> +                   <GIC_SPI 855 IRQ_TYPE_EDGE_RISING>,
> +                   <GIC_SPI 856 IRQ_TYPE_EDGE_RISING>;
> +      interrupt-names = "adi", "gbadi", "gcadi",
> +                        "cmpai", "cmpbi", "wcmpm", "wcmpum";
> +      clocks = <&cpg CPG_CORE R9A09G077_CLK_PCLKL>,
> +               <&cpg CPG_MOD 225>;
> +      clock-names = "adclk", "pclk";
> +      power-domains = <&cpg>;
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +      #io-channel-cells = <1>;
> +      renesas,max-channels = <6>;
> +
> +      channel@0 {
> +        reg = <0x0>;
> +      };
> +      channel@1 {
> +        reg = <0x1>;
> +      };
> +      channel@2 {
> +        reg = <0x2>;
> +      };
> +      channel@3 {
> +        reg = <0x3>;
> +      };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 9f4b48801879..07e0d37cf468 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21822,6 +21822,13 @@ S:	Supported
>  F:	Documentation/devicetree/bindings/timer/renesas,rz-mtu3.yaml
>  F:	drivers/counter/rz-mtu3-cnt.c
>  
> +RENESAS RZ/T2H / RZ/N2H A/D DRIVER
> +M:	Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
> +L:	linux-iio@vger.kernel.org
> +L:	linux-renesas-soc@vger.kernel.org
> +S:	Supported
> +F:	Documentation/devicetree/bindings/iio/adc/renesas,r9a09g077-adc.yaml
> +
>  RENESAS RTCA-3 RTC DRIVER
>  M:	Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>  L:	linux-rtc@vger.kernel.org
> -- 
> 2.51.0
> 

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