Re: [PATCH v3 1/2] dt-bindings: hwmon: pmbus: Add Infineon tda38740 and tda38725

[Conor Dooley <conor@kernel.org>]

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On Thu, Sep 10, 2026 at 02:18:55PM +0800, Colin Huang wrote:
> From: Colin Huang <u8813345@gmail.com>
> 
> Add devicetree bindings for the Infineon TDA38740 and TDA38725
> single-voltage synchronous buck regulators with PMBus interface.
> 
> Signed-off-by: Colin Huang <u8813345@gmail.com>
> ---
>  .../bindings/hwmon/pmbus/infineon,tda38740.yaml    | 87 ++++++++++++++++++++++
>  1 file changed, 87 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38740.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38740.yaml
> new file mode 100644
> index 000000000000..28e6ff9d9d9c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38740.yaml
> @@ -0,0 +1,87 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +
> +$id: http://devicetree.org/schemas/hwmon/pmbus/infineon,tda38740.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Infineon TDA38740 and TDA38725 PMBus Synchronous Buck Regulator
> +
> +maintainers:
> +  - Colin Huang <u8813345@gmail.com>
> +
> +description: |
> +  The Infineon TDA38740/TDA38725 is a 40A/25A single-voltage synchronous
> +  buck regulator with a PMBus interface designed for industrial use.
> +
> +  Datasheet:
> +  https://www.infineon.com/row/public/documents/24/49/infineon-tda38740-tda38725-datasheet-en.pdf
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - const: infineon,tda38740
> +      - const: infineon,tda38725
> +    description: |
> +      The Infineon TDA38740 and TDA38725 share the same PMBus programming
> +      model. Use infineon,tda38740 as the preferred compatible string;
> +      infineon,tda38725 is kept as a compatibility alias.

This is not how this should be done. Instead, tda38725 should list
tda38740 as a fallback compatible. Take a look at the example schema for
how this can be done.
Otherwise, this looks okay to me.

pw-bot: changes-requested

Thanks,
Conor.

> +
> +  reg:
> +    maxItems: 1
> +
> +  infineon,vout-scale-micro:
> +    description: |
> +      Scaling factor applied to READ_VOUT telemetry.
> +
> +      TDA38740/25 pin strap parts are available in two flavors of
> +      VOUT_SCALE_LOOP: 1:1 and 1:2.
> +
> +      For the 1:1 VOUT_SCALE_LOOP version, output voltage sense pins are
> +      directly connected to the output, and no resistor divider is used.
> +
> +      For the 1:2 version, a resistor divider is typically used (for example,
> +      499 ohms for both top and bottom resistors).
> +
> +      In some designs, users intentionally modify the feedback divider ratio
> +      to obtain an output voltage different from the internally configured
> +      VBOOT or VOUT value.
> +
> +      In such cases, the device telemetry (READ_VOUT) continues to report
> +      the internally programmed voltage and does not reflect the actual
> +      externally adjusted output voltage.
> +
> +      This property provides a multiplier to scale the reported telemetry
> +      value so that the monitoring system reflects the actual output voltage.
> +
> +      The value shall be expressed in micro units where 1,000,000 represents
> +      a scaling factor of 1.0.
> +
> +      Example:
> +        If actual Vout = 0.75V and READ_VOUT reports 0.7V:
> +        scaling factor = 0.75 / 0.7 = 1.071
> +        value = 1071000
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    default: 1000000
> +    minimum: 100000
> +    maximum: 2000000
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        sensor@40 {
> +            compatible = "infineon,tda38740";
> +            reg = <0x40>;
> +            infineon,vout-scale-micro = <1071000>;
> +        };
> +    };
> +
> 
> -- 
> 2.34.1
> 

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