[v2] arm64: dts: qcom: sc7280: Adjust zombie PWM frequency

[PATCH v2] arm64: dts: qcom: sc7280: Adjust zombie PWM frequency

Posted by Owen Yang 2 years, 7 months ago

Tune the PWM to solve screen flashing issue and high frequency noise.
While at it, the comment for the PWM settings incorrectly said we were using a 5kHz duty cycle. It should have said "period", not "duty cycle".
Correct this while updating the values.

Signed-off-by: Owen Yang <ecs.taipeikernel@gmail.com>
---

Changes in v2:
-Correct unit and update values in comment.

 arch/arm64/boot/dts/qcom/sc7280-herobrine-zombie.dtsi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7280-herobrine-zombie.dtsi b/arch/arm64/boot/dts/qcom/sc7280-herobrine-zombie.dtsi
index 64deaaabac0f..a4fde22e3355 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-herobrine-zombie.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280-herobrine-zombie.dtsi
@@ -61,8 +61,8 @@ ap_tp_i2c: &i2c0 {
 };
 
 &pm8350c_pwm_backlight {
-	/* Set the PWM period to 200 microseconds (5kHz duty cycle) */
-	pwms = <&pm8350c_pwm 3 200000>;
+	/* Set the PWM period to 320 microseconds (3.125kHz frequency) */
+	pwms = <&pm8350c_pwm 3 320000>;
 };
 
 &pwmleds {
-- 
2.17.1

Re: [PATCH v2] arm64: dts: qcom: sc7280: Adjust zombie PWM frequency

Posted by Bjorn Andersson 2 years, 7 months ago

On Mon, 13 Feb 2023 10:59:05 +0800, Owen Yang wrote:
> Tune the PWM to solve screen flashing issue and high frequency noise.
> While at it, the comment for the PWM settings incorrectly said we were using a 5kHz duty cycle. It should have said "period", not "duty cycle".
> Correct this while updating the values.
> 
> 

Applied, thanks!

[1/1] arm64: dts: qcom: sc7280: Adjust zombie PWM frequency
      commit: f15c1b1bd3c2b3a688d1139593be6c620bb9af6f

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>

Re: [PATCH v2] arm64: dts: qcom: sc7280: Adjust zombie PWM frequency

Posted by Matthias Kaehlcke 2 years, 7 months ago

On Mon, Feb 13, 2023 at 10:59:05AM +0800, Owen Yang wrote:
> Tune the PWM to solve screen flashing issue and high frequency noise.
> While at it, the comment for the PWM settings incorrectly said we were using a 5kHz duty cycle. It should have said "period", not "duty cycle".

Please split this into two lines

> Correct this while updating the values.
> 
> Signed-off-by: Owen Yang <ecs.taipeikernel@gmail.com>

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

Re: [PATCH v2] arm64: dts: qcom: sc7280: Adjust zombie PWM frequency

Posted by Doug Anderson 2 years, 7 months ago

Hi,

On Mon, Feb 13, 2023 at 8:45 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> On Mon, Feb 13, 2023 at 10:59:05AM +0800, Owen Yang wrote:
> > Tune the PWM to solve screen flashing issue and high frequency noise.
> > While at it, the comment for the PWM settings incorrectly said we were using a 5kHz duty cycle. It should have said "period", not "duty cycle".
>
> Please split this into two lines
>
> > Correct this while updating the values.
> >
> > Signed-off-by: Owen Yang <ecs.taipeikernel@gmail.com>
>
> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

Reviewed-by: Douglas Anderson <dianders@chromium.org>