linux-kernel - Re: [PATCH v2] arm64: dts: qcom: hamoa-iot-evk: Add backlight support for eDP panel

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Message-ID: <29ef2def-4073-4a77-8437-41cdfac2fa9d@oss.qualcomm.com>
Date: Thu, 6 Nov 2025 11:15:45 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Yongxing Mou <yongxing.mou@....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 v2] arm64: dts: qcom: hamoa-iot-evk: Add backlight support
 for eDP panel

On 11/6/25 8:12 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.

Adding the hardware description to the DT with the reason that some prior
boot stage might not have taken care of it is not great

How about:

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

Konrad