Re: [PATCH v5 03/12] arm64: dts: rockchip: Use a longer PWM period for the fan on Radxa ROCK 5C

Dragan Simic
2024-12-16T12:44:06Z

On 2024-12-16 12:30, FUKAUMI Naoki wrote:
> The fan on Radxa ROCK 5C is driven via an AO3416 MOSFET, which has a
> total switch-on time of 0,6us and a total switch-off time of 6us [1],
> meaning that the current PWM period of just 10us is too short for
> fine-grained fan speed control. Increase the PWM period to 60us, so
> that the switch-on and switch-off time of the MOSFET fall within a
> more reasonable ~10% of the full period, thus making lower PWM duty
> cycles meaningful.
>
> [1] https://www.aosmd.com/pdfs/datasheet/AO3416.pdf
>
> Fixes: 3ddf5cdb77e6 ("arm64: dts: rockchip: add Radxa ROCK 5C")
> Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>

Looking good to me. Please, feel free to include:

Reviewed-by: Dragan Simic <dsimic@manjaro.org>

> ---
> Changes in v5:
> - Reword commit message (Alexey Charkov)
> Changes in v4:
> - none
> Changes in v3:
> - none
> Changes in v2:
> - reword commit message
> ---
> 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 630f026d856c..85589d1a6d3b 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3588s-rock-5c.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3588s-rock-5c.dts
> @@ -73,7 +73,7 @@ pwm-fan {
> #cooling-cells = <2>;
> cooling-levels = <0 64 128 192 255>;
> fan-supply = <&vcc_5v0>;
> - pwms = <&pwm3 0 10000 0>;
> + pwms = <&pwm3 0 60000 0>;
> };
>
> pcie2x1l2_3v3: regulator-pcie2x1l2-3v3 {