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Date:   Mon, 4 Oct 2021 11:57:27 -0500
From:   Rob Herring <robh@kernel.org>
To:     Olivier Moysan <olivier.moysan@foss.st.com>
Cc:     Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Fabrice Gasnier <fabrice.gasnier@st.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com
Subject: Re: [PATCH v3 1/7] dt-bindings: iio: stm32-adc: add generic channel
 binding
Message-ID: <YVsyd+O08h62NVwi@robh.at.kernel.org>
References: <20210924083410.12332-1-olivier.moysan@foss.st.com>
 <20210924083410.12332-2-olivier.moysan@foss.st.com>
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On Fri, Sep 24, 2021 at 10:34:04AM +0200, Olivier Moysan wrote:
> Add ADC generic channel binding. This binding should
> be used as an alternate to legacy channel properties
> whenever possible.
> ADC generic channel binding allows to identify supported
> internal channels through the following reserved label names:
> "vddcore", "vrefint" and "vbat".
> This binding also allows to set a different sampling time
> for each channel.
> 
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
> ---
>  .../bindings/iio/adc/st,stm32-adc.yaml        | 100 ++++++++++++++++--
>  1 file changed, 93 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
> index a58334c3bb76..1c13921b0556 100644
> --- a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
> @@ -222,6 +222,12 @@ patternProperties:
>        '#io-channel-cells':
>          const: 1
>  
> +      '#address-cells':
> +        const: 1
> +
> +      '#size-cells':
> +        const: 0
> +
>        interrupts:
>          description: |
>            IRQ Line for the ADC instance. Valid values are:
> @@ -256,6 +262,7 @@ patternProperties:
>              - 20 channels, numbered from 0 to 19 (for in0..in19) on stm32h7 and
>                stm32mp1.
>          $ref: /schemas/types.yaml#/definitions/uint32-array
> +        deprecated: true
>  
>        st,adc-diff-channels:
>          description: |
> @@ -265,7 +272,9 @@ patternProperties:
>            <vinp vinn>, <vinp vinn>,... vinp and vinn are numbered from 0 to 19.
>  
>            Note: At least one of "st,adc-channels" or "st,adc-diff-channels" is
> -          required. Both properties can be used together. Some channels can be
> +          required if no adc generic channel is defined. These legacy channel
> +          properties are exclusive with adc generic channel bindings.
> +          Both properties can be used together. Some channels can be
>            used as single-ended and some other ones as differential (mixed). But
>            channels can't be configured both as single-ended and differential.
>          $ref: /schemas/types.yaml#/definitions/uint32-matrix
> @@ -279,6 +288,7 @@ patternProperties:
>                  "vinn" indicates negative input number
>                minimum: 0
>                maximum: 19
> +        deprecated: true
>  
>        st,min-sample-time-nsecs:
>          description:
> @@ -289,6 +299,42 @@ patternProperties:
>            list, to set sample time resp. for all channels, or independently for
>            each channel.
>          $ref: /schemas/types.yaml#/definitions/uint32-array
> +        deprecated: true
> +
> +    patternProperties:
> +      "^channel@([0-9]|1[0-9])$":
> +        type: object
> +        $ref: "adc.yaml"

You need 'additionalProperties: false' here. Or unevaluatedProperties if 
there are properties used and defined in adc.yaml, but not here.

> +        description: |

Don't need '|' unless you need to maintain formatting (line breaks).

> +          Represents the external channels which are connected to the ADC.
> +
> +        properties:
> +          reg:
> +            items:
> +              minimum: 0
> +              maximum: 19
> +
> +          label:
> +            description: |
> +              Unique name to identify which channel this is.
> +              Reserved label names "vddcore", "vrefint" and "vbat"
> +              are used to identify internal channels with matching names.
> +
> +          diff-channels:
> +            $ref: /schemas/types.yaml#/definitions/uint32-array
> +            items:
> +              minimum: 0
> +              maximum: 19
> +
> +          st,min-sample-time-nsecs:

Use standard unit suffix (-ns).

> +            $ref: /schemas/types.yaml#/definitions/uint32

And then drop this.

> +            description: |
> +              Minimum sampling time in nanoseconds. Depending on hardware (board)
> +              e.g. high/low analog input source impedance, fine tune of ADC
> +              sampling time may be recommended.
> +
> +        required:
> +          - reg
>  
>      allOf:
>        - if:
> @@ -369,12 +415,6 @@ patternProperties:
>  
>      additionalProperties: false
>  
> -    anyOf:
> -      - required:
> -          - st,adc-channels
> -      - required:
> -          - st,adc-diff-channels
> -
>      required:
>        - compatible
>        - reg
> @@ -451,4 +491,50 @@ examples:
>          // other adc child node follow...
>        };
>  
> +  - |
> +    // Example 3: with stm32mp157c to setup ADC2 with:
> +    // - internal channels 13, 14, 15.
> +      #include <dt-bindings/interrupt-controller/arm-gic.h>
> +      #include <dt-bindings/clock/stm32mp1-clks.h>
> +      adc122: adc@48003000 {
> +        compatible = "st,stm32mp1-adc-core";
> +        reg = <0x48003000 0x400>;
> +        interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>,
> +                     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>;
> +        clocks = <&rcc ADC12>, <&rcc ADC12_K>;
> +        clock-names = "bus", "adc";
> +        booster-supply = <&booster>;
> +        vdd-supply = <&vdd>;
> +        vdda-supply = <&vdda>;
> +        vref-supply = <&vref>;
> +        st,syscfg = <&syscfg>;
> +        interrupt-controller;
> +        #interrupt-cells = <1>;
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        adc@100 {
> +          compatible = "st,stm32mp1-adc";
> +          #io-channel-cells = <1>;
> +          reg = <0x100>;
> +          interrupts = <1>;
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +          channel@13 {
> +            reg = <13>;
> +            label = "vrefint";
> +            st,min-sample-time-nsecs = <9000>;
> +          };
> +          channel@14 {
> +            reg = <14>;
> +            label = "vddcore";
> +            st,min-sample-time-nsecs = <9000>;
> +          };
> +          channel@15 {
> +            reg = <15>;
> +            label = "vbat";
> +            st,min-sample-time-nsecs = <9000>;
> +          };
> +        };
> +      };
> +
>  ...
> -- 
> 2.17.1
> 
>