Re: [PATCH 1/7] dt-bindings: iio: adc: Add support for QCOM PMIC5 Gen4 ADC

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 31 Jul 2026 23:36:14 +0530
Jishnu Prakash <jishnu.prakash@oss.qualcomm.com> wrote:

> PMIC5 Gen4 ADC is similar to PMIC5 Gen3 ADC, with several changes made for
> improved performance, mostly at the hardware level. The main differences are
> increased ratiometric conversion resolution (from 14 bits to 16 bits) and
> increased bit field width for PMIC SID (to allow communication with an
> increased number of PMICs, supported on latest SoCs).

Hi Jishnu,

The mixed case is enough of a surprise (to me least) that I'd expect
there to either be more discussion here or for it to be handled first
as a dt binding patch to allow for v4 channels on v3 hardware.

That would provide a place for a description of why that is necessary and
then the following gen4 dt-bindings patch with gen3 channels would seem
like a natural extension.

Other than that this seems fine to me.

Jonathan

> 
> Signed-off-by: Jishnu Prakash <jishnu.prakash@oss.qualcomm.com>
> ---
>  .../bindings/iio/adc/qcom,spmi-adc5-gen3.yaml      | 47 +++++++++++++++++++++-
>  1 file changed, 46 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-adc5-gen3.yaml b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-adc5-gen3.yaml
> index 149f4af8f4b8..e79ddc2acca0 100644
> --- a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-adc5-gen3.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-adc5-gen3.yaml
> @@ -21,9 +21,14 @@ description: |
>    All boards using a particular (SOC + master PMIC) combination will have the
>    same number of ADC SDAMs supported on that PMIC.
>  
> +  PMIC5 Gen4 ADC is similar to Gen3 ADC, with some differences such as
> +  improved ratiometric conversion resolution.
> +
>  properties:
>    compatible:
> -    const: qcom,spmi-adc5-gen3
> +    enum:
> +      - qcom,spmi-adc5-gen3
> +      - qcom,spmi-adc5-gen4
>  
>    reg:
>      items:
> @@ -83,6 +88,46 @@ patternProperties:
>            This property indicates ADC_TM monitoring is done on this channel.
>          type: boolean
>  
> +      qcom,adc5-gen4:
> +        description:
> +          Indicates channel is of type ADC5 Gen4. This may be needed in cases where the
> +          master PMIC has an ADC peripheral of type Gen3, but some of the other PMICs it
> +          communicates with have ADC peripherals of type Gen4, so channels of those PMICs
> +          need to be marked as Gen4 to ensure their conversions are handled correctly.
> +        type: boolean
> +
> +      qcom,adc5-gen3:
> +        description:
> +          Indicates channel is of type ADC5 Gen3. This may be needed in cases where the
> +          master PMIC has an ADC peripheral of type Gen4, but some of the other PMICs
> +          under it have ADC peripherals of type Gen3.
> +        type: boolean
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: qcom,spmi-adc5-gen4
> +
> +    then:
> +      patternProperties:
> +        "^channel@[0-9a-f]+$":
> +          properties:
> +            qcom,adc5-gen4: false
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: qcom,spmi-adc5-gen3
> +
> +    then:
> +      patternProperties:
> +        "^channel@[0-9a-f]+$":
> +          properties:
> +            qcom,adc5-gen3: false
> +
>  required:
>    - compatible
>    - reg
>