| Message ID | 20241216113052.15696-4-naoki@radxa.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: dts: rockchip: Refine dts for Radxa ROCK 5C | expand |
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 {
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 {
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> --- 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(-)