Re: [RFC PATCH v2 1/2] dt-bindings: hwmon: emc2305: Add fan-shutdown-percent property

[Conor Dooley]

On Thu, Mar 12, 2026 at 02:22:47PM +0200, florin.leotescu@xxxxxxxxxxx wrote:
> From: Florin Leotescu <florin.leotescu@xxxxxxx>
> 
> The EMC2305 fan controller supports multiple independent PWM fan
> outputs. Some systems require fans to enter a defined safe state
> during system shutdown or reboot handoff, until firmware or the next
> boot stage reconfigures the controller.
> 
> Add an optional "fan-shutdown-percent" property to fan child nodes
> allowing the shutdown fan speed to be configured per fan output.
> 
> Signed-off-by: Florin Leotescu <florin.leotescu@xxxxxxx>
> ---
>  .../devicetree/bindings/hwmon/microchip,emc2305.yaml      | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/microchip,emc2305.yaml b/Documentation/devicetree/bindings/hwmon/microchip,emc2305.yaml
> index d3f06ebc19fa..7bcadfab9fc4 100644
> --- a/Documentation/devicetree/bindings/hwmon/microchip,emc2305.yaml
> +++ b/Documentation/devicetree/bindings/hwmon/microchip,emc2305.yaml
> @@ -54,6 +54,12 @@ patternProperties:
>            The fan number used to determine the associated PWM channel.
>          maxItems: 1
>  
> +      fan-shutdown-percent:
> +        description:
> +          Fan RPM in percent set during shutdown.

This sounds like something generic, that other devices might need and
should be in fan-common.yaml?

> +        minimum: 0
> +        maximum: 100
> +
>      required:
>        - reg
>  
> @@ -80,12 +86,14 @@ examples:
>              fan@0 {
>                  reg = <0x0>;
>                  pwms = <&fan_controller 26000 PWM_POLARITY_INVERTED 1>;
> +                fan-shutdown-percent = <100>;
>                  #cooling-cells = <2>;
>              };
>  
>              fan@1 {
>                  reg = <0x1>;
>                  pwms = <&fan_controller 26000 0 1>;
> +                fan-shutdown-percent = <50>;
>                  #cooling-cells = <2>;
>              };
>  
> -- 
> 2.34.1
>

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