linux-kernel - Re: [PATCH v3] arm64: dts: qcom: hamoa-iot-evk: Add backlight support for eDP panel

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Message-ID: <e28915a0-e263-46b7-8093-904dfefcc308@oss.qualcomm.com>
Date: Mon, 5 Jan 2026 11:07:37 +0800
From: Yongxing Mou <yongxing.mou@....qualcomm.com>
To: 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, Abel Vesa <abel.vesa@...aro.org>
Subject: Re: [PATCH v3] arm64: dts: qcom: hamoa-iot-evk: Add backlight support
 for eDP panel



On 11/12/2025 12:21 PM, Yongxing Mou wrote:
> The backlight on the Hamoa IoT EVK is controlled through a PWM signal.
> Aligned with other x1e80100-based platforms: the PWM signal is controlled
> by PMK8550, and the backlight enable signal is handled by PMC8380.
> 
> Describe the backlight device and connect it to the eDP panel to allow
> for brightness control.
> 
> Reviewed-by: Abel Vesa <abel.vesa@...aro.org>
> Signed-off-by: Yongxing Mou <yongxing.mou@....qualcomm.com>
> ---
> Changes in v3:
> - Optimize the description of the commit message. [Konrad]
> - Drop empty line. [Abel]
> - Link to v2: https://lore.kernel.org/r/20251106-hamoa_dvt_backlight-v2-1-9f844c8f8110@oss.qualcomm.com
> 
> Changes in v2:
> - Add hamoa-iot-evk to the commit subject. [Konrad]
> - Correct the property order in the vreg_edp_bl node. [Konrad]
> - Link to v1: https://lore.kernel.org/r/20251028-hamoa_dvt_backlight-v1-1-97ecb8d0ad01@oss.qualcomm.com
> ---
>   arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts | 54 ++++++++++++++++++++++++++++++
>   1 file changed, 54 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts b/arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts
> index 36dd6599402b..499db4d67583 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>;
> +		enable-gpios = <&pmc8380_3_gpios 4 GPIO_ACTIVE_HIGH>;
> +		power-supply = <&vreg_edp_bl>;
> +
> +		pinctrl-0 = <&edp_bl_en>, <&edp_bl_pwm>;
> +		pinctrl-names = "default";
> +	};
> +
>   	wcd938x: audio-codec {
>   		compatible = "qcom,wcd9385-codec";
>   
> @@ -183,6 +193,22 @@ vreg_edp_3p3: regulator-edp-3p3 {
>   		regulator-boot-on;
>   	};
>   
> +	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-0 = <&edp_bl_reg_en>;
> +		pinctrl-names = "default";
> +
> +		regulator-boot-on;
> +	};
> +
>   	vreg_nvme: regulator-nvme {
>   		compatible = "regulator-fixed";
>   
> @@ -819,6 +845,8 @@ &mdss_dp3 {
>   	aux-bus {
>   		panel {
>   			compatible = "edp-panel";
> +
> +			backlight = <&backlight>;
>   			power-supply = <&vreg_edp_3p3>;
>   
>   			port {
> @@ -879,6 +907,21 @@ usb0_1p8_reg_en: usb0-1p8-reg-en-state {
>   	};
>   };
>   
> +&pmc8380_3_gpios {
> +	edp_bl_en: edp-bl-en-state {
> +		pins = "gpio4";
> +		function = "normal";
> +		power-source = <1>;
> +		input-disable;
> +		output-enable;
> +	};
> +
> +	edp_bl_reg_en: edp-bl-reg-en-state {
> +		pins = "gpio10";
> +		function = "normal";
> +	};
> +};
> +
>   &pmc8380_5_gpios {
>   	usb0_pwr_1p15_reg_en: usb0-pwr-1p15-reg-en-state {
>   		pins = "gpio8";
> @@ -890,6 +933,17 @@ usb0_pwr_1p15_reg_en: usb0-pwr-1p15-reg-en-state {
>   	};
>   };
>   
> +&pmk8550_gpios {
> +	edp_bl_pwm: edp-bl-pwm-state {
> +		pins = "gpio5";
> +		function = "func3";
> +	};
> +};
> +
> +&pmk8550_pwm {
> +	status = "okay";
> +};
> +
>   &smb2360_0 {
>   	status = "okay";
>   };
> 
> ---
> base-commit: f7d2388eeec24966fc4d5cf32d706f0514f29ac5
> change-id: 20251028-hamoa_dvt_backlight-373528b7ce7e
> 
> Best regards,
Just a friendly reminder, can we pick this change to tree?