Re: [PATCH 1/2] arm64: dts: rockchip: Add finer-grained PWM states for the fan on Rock 5C

[Dragan Simic]

Hello Alexey,

On 2025-01-20 20:22, Alexey Charkov wrote:
> Radxa Heatsink 6540B, which is the official cooling accessory for the
> Rock 5C board, includes a small 5V fan, which in my testing spins up
> reliably at a PWM setting of 24 (out of 255). It is also quite loud
> at the current minimum setting of 64, and noticeably less so at 24.
>
> Introduce two intermediate PWM states at the lower end of the fan's
> operating range to enable better balance between noise and cooling.
>
> Note further that, in my testing, having the fan run at 44 is enough
> to keep the system from thermal throttling with sustained 100% load
> on its 8 CPU cores (in 22C ambient temperature and no case)
>
> Signed-off-by: Alexey Charkov <alchark@xxxxxxxxx>

Thanks for the patch, it's looking good to me and the explanations
are fine.  Please, feel free to include

Acked-by: Dragan Simic <dsimic@xxxxxxxxxxx>

> ---
>  arch/arm64/boot/dts/rockchip/rk3588s-rock-5c.dts | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/boot/dts/rockchip/rk3588s-rock-5c.dts
> b/arch/arm64/boot/dts/rockchip/rk3588s-rock-5c.dts
> index
> 9b14d5383cdc16947c955b1c6e2a32a50c5df3e6..1b66a69cf0f8795d7305852fa7fef3d0672ada7f
> 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3588s-rock-5c.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3588s-rock-5c.dts
> @@ -71,7 +71,7 @@ led-1 {
>  	fan {
>  		compatible = "pwm-fan";
>  		#cooling-cells = <2>;
> -		cooling-levels = <0 64 128 192 255>;
> +		cooling-levels = <0 24 44 64 128 192 255>;
>  		fan-supply = <&vcc_5v0>;
>  		pwms = <&pwm3 0 10000 0>;
>  	};