Re: [PATCH 1/2] dt-bindings: hwmon: pwm-fan: Document after shutdown fan settings

[Rob Herring <robh@kernel.org>]

On Mon, Jun 30, 2025 at 12:02:08AM +0200, Marek Vasut wrote:
> Document fan-shutdown-percent property, used to describe fan RPM in percent
> set during shutdown. This is used to keep the fan running at fixed RPM after
> the kernel shut down, which is useful on hardware that does keep heating
> itself even after the kernel did shut down, for example from some sort of
> management core.

This sounds more like "don't ever let the fan go below this RPM" or 
"don't ever turn off the fan". IOW, it is more than just shutdown.

> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Jean Delvare <jdelvare@suse.com>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: devicetree@vger.kernel.org
> Cc: linux-hwmon@vger.kernel.org
> Cc: linux-renesas-soc@vger.kernel.org
> ---
>  Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
> index 8b4ed5ee962f..a84cc3a4cfdc 100644
> --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
> +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
> @@ -31,6 +31,15 @@ properties:
>        it must be self resetting edge interrupts.
>      maxItems: 1
>  
> +  fan-shutdown-percent:
> +    description:
> +      Fan RPM in percent set during shutdown. This is used to keep the fan
> +      running at fixed RPM after the kernel shut down, which is useful on
> +      hardware that does keep heating itself even after the kernel did shut
> +      down, for example from some sort of management core.
> +    minimum: 0
> +    maximum: 100
> +
>    fan-stop-to-start-percent:
>      description:
>        Minimum fan RPM in percent to start when stopped.
> -- 
> 2.47.2
>