arm64: dts: apple: t8103: Add dp-altmode dts hacks

Enable DP alt mode for all M1 devices:
- Mac Mini (M1): USB-C port next to the HDMI port
- Macbook Pro (M1, 13-inch): front left USB-C port
- Macbook Air (M1, 13-inch): front left USB-C port
- iMac (M1, 2 USB-C ports): back left USB-C port
- iMac (M1, 4 USB-C ports): back right middle USB-C port

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

arch/arm64/boot/dts/apple/t8103-jxxx.dtsi

@@ -9,10 +9,15 @@
  * Copyright The Asahi Linux Contributors
  */
 
+#define ENABLE_DCPEXT_TYPEC
+
 / {
 	aliases {
 		bluetooth0 = &bluetooth0;
 		dcp = &dcp;
+#ifdef ENABLE_DCPEXT_TYPEC
+		dcpext = &dcpext;
+#endif
 		disp0 = &display;
 		disp0_piodma = &disp0_piodma;
 		serial0 = &serial0;
@@ -103,6 +108,11 @@
 			power-role = "dual";
 			data-role = "dual";
 
+#ifdef ENABLE_DCPEXT_TYPEC
+			/* hacks */
+			displayport = <&dcpext>;
+#endif
+
 			ports {
 				#address-cells = <1>;
 				#size-cells = <0>;
@@ -123,6 +133,41 @@
 	};
 };
 
+#ifdef ENABLE_DCPEXT_TYPEC
+&display {
+	iommus = <&disp0_dart 0>, <&dispext0_dart 0>;
+};
+
+&dispext0_dart {
+	status = "okay";
+};
+
+&dcpext_dart {
+	status = "okay";
+};
+
+&dcpext_mbox {
+	status = "okay";
+};
+
+&dcpext {
+	status = "okay";
+	apple,connector-type = "DP";
+
+	/* hacks */
+	apple,dptx-phy = <1>;
+	phys = <&atcphy1 PHY_TYPE_DP>;
+	phy-names = "dp-phy";
+	mux-controls = <&atcphy1_xbar 0>;
+	mux-control-names = "dp-xbar";
+	mux-index = <0>;
+};
+
+&dpaudio1 {
+	status = "okay";
+};
+#endif
+
 /* USB controllers */
 &dwc3_0 {
 	ports {