Re: [PATCH v4 1/2] dt-bindings: hwmon: emc2305: Add fan-shutdown-percent property

[Daniel Baluta]

On 3/20/26 17:29, 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.
AI review suggests to update description to 'Fan speed percent' or 'PWM duty cycle in percent'. This could be an easy update.
More important question here is how should we proceed with the following observation:

"fan-shutdown-percent property is already defined identically in pwm-fan.yaml."

Guenter, should we move it from pwm-fan.yaml to fan-common.yaml and use it here?

Our initial thought was to add have it merged in microchip,emc2305.yaml as it is now

and then factor it out in fan-common.yaml in a later patch.


What do you think?