linux-kernel - [PATCH 4/5] arm64: dts: qcom: x1e80100-crd: Fix backlight

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Message-Id: <20240710-x1e80100-crd-backlight-v1-4-eb242311a23e@linaro.org>
Date: Wed, 10 Jul 2024 19:05:00 +0200
From: Stephan Gerhold <stephan.gerhold@...aro.org>
To: Neil Armstrong <neil.armstrong@...aro.org>, 
 Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konrad.dybcio@...aro.org>
Cc: Jessica Zhang <quic_jesszhan@...cinc.com>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, 
 Douglas Anderson <dianders@...omium.org>, dri-devel@...ts.freedesktop.org, 
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-arm-msm@...r.kernel.org, Abel Vesa <abel.vesa@...aro.org>, 
 Johan Hovold <johan@...nel.org>
Subject: [PATCH 4/5] arm64: dts: qcom: x1e80100-crd: Fix backlight

The backlight does not work correctly with the current display panel
configuration: It works after boot, but once the display gets disabled it
is not possible to get it back on. It turns out that the ATNA45AF01 panel
needs exactly the same non-standard power sequence as implemented by the
panel-samsung-atna33xc20 driver for sc7180-trogdor-homestar.

Switch the panel in the DT to the new compatible and make two more changes
to make it work correctly:

 1. Add the missing GPIO for the panel EL_ON3 line (EDP_BL_EN on CRD and
    enable-gpios in the DT).
 2. Drop the regulator-always-on for the panel regulator. The panel does
    not seem to power off properly if the regulator stays on.

Signed-off-by: Stephan Gerhold <stephan.gerhold@...aro.org>
---
 arch/arm64/boot/dts/qcom/x1e80100-crd.dts | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/x1e80100-crd.dts b/arch/arm64/boot/dts/qcom/x1e80100-crd.dts
index 6152bcd0bc1f..7d6800dd9b8a 100644
--- a/arch/arm64/boot/dts/qcom/x1e80100-crd.dts
+++ b/arch/arm64/boot/dts/qcom/x1e80100-crd.dts
@@ -268,7 +268,6 @@ vreg_edp_3p3: regulator-edp-3p3 {
 		pinctrl-0 = <&edp_reg_en>;
 		pinctrl-names = "default";
 
-		regulator-always-on;
 		regulator-boot-on;
 	};
 
@@ -724,9 +723,13 @@ &mdss_dp3 {
 
 	aux-bus {
 		panel {
-			compatible = "edp-panel";
+			compatible = "samsung,atna45af01";
+			enable-gpios = <&pmc8380_3_gpios 4 GPIO_ACTIVE_HIGH>;
 			power-supply = <&vreg_edp_3p3>;
 
+			pinctrl-0 = <&edp_bl_en>;
+			pinctrl-names = "default";
+
 			port {
 				edp_panel_in: endpoint {
 					remote-endpoint = <&mdss_dp3_out>;
@@ -785,6 +788,16 @@ &pcie6a_phy {
 	status = "okay";
 };
 
+&pmc8380_3_gpios {
+	edp_bl_en: edp-bl-en-state {
+		pins = "gpio4";
+		function = "normal";
+		power-source = <1>; /* 1.8V */
+		input-disable;
+		output-enable;
+	};
+};
+
 &qupv3_0 {
 	status = "okay";
 };

-- 
2.44.1