arm64: dts: apple: t8112-j473: Enable dcpext0/dptx-phy/dp2hdmi

After all parts are in place enable DCP on the M2 Mac Mini for HDMI
output. Use dcpext for HDMI out

dcp on t8112 and t602x does not wake up after sleep + reset but dcpext*
does. Use dcpext0 for sharing the code with M1* devices.
My interpretation of the tea leaves from Apple's marketing department
suggests that dcpext is more capable (6k 60Hz vs 5k 60Hz) so use dcpext
as long as only one is used.

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

Author: jannau

arch/arm64/boot/dts/apple/t8112-j473.dts

@@ -18,20 +18,52 @@
 
 	aliases {
 		bluetooth0 = &bluetooth0;
+		/delete-property/ dcp;
+		dcpext = &dcpext;
 		ethernet0 = &ethernet0;
 		wifi0 = &wifi0;
 	};
 };
 
 &framebuffer0 {
-	power-domains = <&ps_disp0_cpu0>, <&ps_dptx_ext_phy>;
+	power-domains = <&ps_dispext_cpu0>, <&ps_dptx_ext_phy>;
+};
+
+&dptxphy {
+	status = "okay";
 };
 
-/* disable dcp until it is supported */
 &dcp {
 	status = "disabled";
 };
 
+&display {
+	iommus = <&dispext0_dart 0>;
+};
+&dispext0_dart {
+	status = "okay";
+};
+&dcpext_dart {
+	status = "okay";
+};
+&dcpext_mbox {
+	status = "okay";
+};
+&dcpext {
+	status = "okay";
+	apple,connector-type = "HDMI-A";
+
+	/*  HDMI HPD gpio, used as interrupt*/
+	hdmi-hpd-gpios = <&pinctrl_aop 49 GPIO_ACTIVE_HIGH>;
+
+	hdmi-pwren-gpios = <&smc_gpio 21 GPIO_ACTIVE_HIGH>;
+	dp2hdmi-pwren-gpios = <&smc_gpio 22 GPIO_ACTIVE_HIGH>;
+
+	phys = <&dptxphy>;
+	phy-names = "dp-phy";
+	apple,dptx-phy = <5>;
+};
+
 /*
  * Provide labels for the USB type C ports.
  */