arm64: dts: qcom: x1e78100-lenovo-thinkpad-t14s: add HDMI nodes

The Thinkpad T14s embeds a transparent 4lanes DP->HDMI transceiver
connected to the third QMP Combo PHY 4 lanes.

Add all the data routing, disable mode switching and specify the
QMP Combo PHY should be in DP-Only mode to route the 4 lanes to
the underlying DP phy.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20251119-topic-x1e80100-hdmi-v7-3-2bee0e66cc1b@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: superna9999

arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi

@@ -62,6 +62,45 @@
 		};
 	};
 
+	hdmi-bridge {
+		compatible = "realtek,rtd2171";
+
+		pinctrl-0 = <&hdmi_hpd_default>;
+		pinctrl-names = "default";
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
+				reg = <0>;
+
+				hdmi_bridge_dp_in: endpoint {
+					remote-endpoint = <&usb_1_ss2_qmpphy_out_dp>;
+				};
+			};
+
+			port@1 {
+				reg = <1>;
+
+				hdmi_bridge_tmds_out: endpoint {
+					remote-endpoint = <&hdmi_con>;
+				};
+			};
+		};
+	};
+
+	hdmi-connector {
+		compatible = "hdmi-connector";
+		type = "a";
+
+		port {
+			hdmi_con: endpoint {
+				remote-endpoint = <&hdmi_bridge_tmds_out>;
+			};
+		};
+	};
+
 	pmic-glink {
 		compatible = "qcom,x1e80100-pmic-glink",
 			     "qcom,sm8550-pmic-glink",
@@ -1076,6 +1115,14 @@
 	link-frequencies = /bits/ 64 <1620000000 2700000000 5400000000 8100000000>;
 };
 
+&mdss_dp2 {
+	status = "okay";
+};
+
+&mdss_dp2_out {
+	link-frequencies = /bits/ 64 <1620000000 2700000000 5400000000 8100000000>;
+};
+
 &mdss_dp3 {
 	/delete-property/ #sound-dai-cells;
 
@@ -1371,6 +1418,12 @@
 		output-low;
 	};
 
+	hdmi_hpd_default: hdmi-hpd-default-state {
+		pins = "gpio126";
+		function = "usb2_dp";
+		bias-disable;
+	};
+
 	tpad_default: tpad-default-state {
 		pins = "gpio3";
 		function = "gpio";
@@ -1602,6 +1655,34 @@
 	remote-endpoint = <&retimer_ss1_ss_in>;
 };
 
+&usb_1_ss2_qmpphy {
+	vdda-phy-supply = <&vreg_l2j_1p2>;
+	vdda-pll-supply = <&vreg_l2d_0p9>;
+
+	/delete-property/ mode-switch;
+	/delete-property/ orientation-switch;
+
+	status = "okay";
+
+	ports {
+		port@0 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			/delete-node/ endpoint;
+
+			usb_1_ss2_qmpphy_out_dp: endpoint@0 {
+				reg = <0>;
+
+				data-lanes = <3 2 1 0>;
+				remote-endpoint = <&hdmi_bridge_dp_in>;
+			};
+
+			/* No USB3 lanes connected */
+		};
+	};
+};
+
 &usb_2 {
 	status = "okay";
 };