Re: [PATCH] arm64: dts: qcom: Add backlight support for eDP panel

[Yongxing Mou <yongxing.mou@oss.qualcomm.com>]

On 10/28/2025 5:08 PM, Konrad Dybcio wrote:
> On 10/28/25 8:04 AM, Yongxing Mou wrote:
>> Previously, the eDP panel backlight was enabled via UEFI. Added backlight
>> control node in kernel DTS due to some meta may not enable the backlight.
>>
>> Aligned with other x1e80100-based platforms: the PWM signal is controlled
>> by PMK8550, and the backlight enable signal is handled by PMC8380.
>>
>> Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
>> ---
> 
> The subject must say "hamoa-iot-evk:"
Thanks and got it , will fix it in next version.>> 
arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts | 55 
++++++++++++++++++++++++++++++
>>   1 file changed, 55 insertions(+)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts b/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts
>> index 36dd6599402b4650b7f8ad2c0cd22212116a25fe..fda1b3a3c7673be74832c27849231cba4bc1f25f 100644
>> --- a/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts
>> +++ b/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts
>> @@ -17,6 +17,16 @@ aliases {
>>   		serial1 = &uart14;
>>   	};
>>   
>> +	backlight: backlight {
>> +		compatible = "pwm-backlight";
>> +		pwms = <&pmk8550_pwm 0 5000000>;
> 
> Try adjusting the backlight value.. you'll find some funny behavior
> near the max level.. which reminds me I should send some fixes for
> some laptop DTs
> 
  I tried sliding the backlight between the maximum and minimum values. 
It seems that at a certain sliding speed, when approaching the maximum 
value, there is some brightness flickering. Is this the phenomenon 
you’re referring to?> [...]
> 
>> +	vreg_edp_bl: regulator-edp-bl {
>> +		compatible = "regulator-fixed";
>> +
>> +		regulator-name = "VBL9";
>> +		regulator-min-microvolt = <3600000>;
>> +		regulator-max-microvolt = <3600000>;
>> +
>> +		gpio = <&pmc8380_3_gpios 10 GPIO_ACTIVE_HIGH>;
>> +		enable-active-high;
>> +
>> +		pinctrl-names = "default";
>> +		pinctrl-0 = <&edp_bl_reg_en>;
> 
> property-n
> property-names
> 
> in this order, please
> 
> KonradThanks and got it ,will fix it in next version.