Re: [PATCH v3 1/1] dt-bindings: hwmon: Add maxim max31790

[Conor Dooley <conor@kernel.org>]

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On Tue, Aug 13, 2024 at 08:41:52AM +0000, Chanh Nguyen wrote:
> Add device tree bindings and an example for max31790 device.
> 
> Signed-off-by: Chanh Nguyen <chanh@os.amperecomputing.com>
> ---
> Changes in v2:
>  - Update filename of the maxim,max31790.yaml                        [Krzysztof]
>  - Add the common fan schema to $ref                                 [Krzysztof]
>  - Update the node name to "fan-controller" in maxim,max31790.yaml   [Krzysztof]
>  - Drop "driver" in commit title                                     [Krzysztof]
> Changes in v3:
>  - Drop redundant "bindings" in commit title                         [Krzysztof]
>  - Add the clocks and resets property in example                     [Krzysztof]
>  - Add child node refer to fan-common.yaml                           [Krzysztof, Conor]
> ---
>  .../bindings/hwmon/maxim,max31790.yaml        | 81 +++++++++++++++++++
>  1 file changed, 81 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml b/Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml
> new file mode 100644
> index 000000000000..d28a6373edd3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml
> @@ -0,0 +1,81 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/maxim,max31790.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: The Maxim MAX31790 Fan Controller
> +
> +maintainers:
> +  - Guenter Roeck <linux@roeck-us.net>

Why Guenter and not you?

> +
> +description: >
> +  The MAX31790 controls the speeds of up to six fans using six
> +  independent PWM outputs. The desired fan speeds (or PWM duty cycles)
> +  are written through the I2C interface.
> +
> +  Datasheets:
> +    https://datasheets.maximintegrated.com/en/ds/MAX31790.pdf
> +
> +properties:
> +  compatible:
> +    const: maxim,max31790
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  resets:
> +    maxItems: 1
> +
> +  "#pwm-cells":
> +    const: 1
> +
> +patternProperties:
> +  "^fan-[0-9]+$":
> +    $ref: fan-common.yaml#
> +    unevaluatedProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +      fan-controller@21 {
> +        compatible = "maxim,max31790";
> +        reg = <0x21>;
> +        clocks = <&sys_clk>;
> +        resets = <&reset 0>;
> +      };
> +    };

What does this example demonstrate? The one below seems useful, this one
I don't quite understand - what's the point of a fan controller with no
fans connected to it? What am I missing?

Otherwise, this looks pretty good.

Cheers,
Conor.

> +  - |
> +    i2c {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +      pwm_provider: fan-controller@20 {
> +        compatible = "maxim,max31790";
> +        reg = <0x20>;
> +        clocks = <&sys_clk>;
> +        resets = <&reset 0>;
> +        #pwm-cells = <1>;
> +
> +        fan-0 {
> +          pwms = <&pwm_provider 1>;
> +        };
> +
> +        fan-1 {
> +          pwms = <&pwm_provider 2>;
> +        };
> +      };
> +    };
> +
> -- 
> 2.43.0
> 

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