arm64: dts: qcom: acer-aspire1: Add embedded controller

The laptop contains an embedded controller that provides a set of
features:

- Battery and charger monitoring
- USB Type-C DP alt mode HPD monitoring
- Lid status detection
- Small amount of keyboard configuration*

[*] The keyboard is handled by the same EC but it has a dedicated i2c
bus and is already enabled. This port only provides fn key behavior
configuration.

Add the EC to the device tree and describe the relationship between the
EC-managed type-c port and the SoC DisplayPort.

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Nikita Travkin <nikita@trvn.ru>
Link: https://lore.kernel.org/r/20240315-aspire1-ec-v5-4-f93381deff39@trvn.ru
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

arch/arm64/boot/dts/qcom/sc7180-acer-aspire1.dts

@@ -255,7 +255,25 @@ &i2c2 {
 	clock-frequency = <400000>;
 	status = "okay";
 
-	/* embedded-controller@76 */
+	embedded-controller@76 {
+		compatible = "acer,aspire1-ec";
+		reg = <0x76>;
+
+		interrupts-extended = <&tlmm 30 IRQ_TYPE_LEVEL_LOW>;
+
+		pinctrl-0 = <&ec_int_default>;
+		pinctrl-names = "default";
+
+		connector {
+			compatible = "usb-c-connector";
+
+			port {
+				ec_dp_in: endpoint {
+					remote-endpoint = <&mdss_dp_out>;
+				};
+			};
+		};
+	};
 };
 
 &i2c4 {
@@ -419,6 +437,19 @@ &mdss {
 	status = "okay";
 };
 
+&mdss_dp {
+	data-lanes = <0 1>;
+
+	vdda-1p2-supply = <&vreg_l3c_1p2>;
+	vdda-0p9-supply = <&vreg_l4a_0p8>;
+
+	status = "okay";
+};
+
+&mdss_dp_out {
+	remote-endpoint = <&ec_dp_in>;
+};
+
 &mdss_dsi0 {
 	vdda-supply = <&vreg_l3c_1p2>;
 	status = "okay";
@@ -857,6 +888,13 @@ codec_irq_default: codec-irq-deault-state {
 		bias-disable;
 	};
 
+	ec_int_default: ec-int-default-state {
+		pins = "gpio30";
+		function = "gpio";
+		drive-strength = <2>;
+		bias-disable;
+	};
+
 	edp_bridge_irq_default: edp-bridge-irq-default-state {
 		pins = "gpio11";
 		function = "gpio";