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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0cf2521b-8d05-42f0-aab8-35cd370e599e@oss.qualcomm.com>
Date: Thu, 30 Oct 2025 17:08:25 +0800
From: Yongxing Mou <yongxing.mou@....qualcomm.com>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm64: dts: qcom: Add backlight support for eDP panel



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@....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.