arm64: dts: apple: t8112-j473: Keep the HDMI port powered on

Add the display controller and DPTX phy power-domains to the framebuffer
node to keep the framebuffer and display out working after device probing
finished.
The OS has more control about the display pipeline used for the HDMI
output on M2 based devices. The HDMI output is driven by an integrated
DisplayPort to HDMI converter (Parade PS190). The DPTX phy is now
controlled by the OS and no longer by firmware running on the display
co-processor. This allows using the second display controller on the
second USB type-c port or tunneling 2 DisplayPort connections over
USB4/Thunderbolt.
The m1n1 bootloader uses the second display controller to drive the HDMI
output. Adjust for this difference compared to the notebooks as well.

Fixes: 2d5ce3f ("arm64: dts: apple: t8112: Initial t8112 (M2) device trees")
Cc: stable@vger.kernel.org
Signed-off-by: Janne Grunau <j@jannau.net>
Link: https://patch.msgid.link/20260108-apple-dt-pmgr-fixes-v1-1-cfdce629c0a8@jannau.net
Signed-off-by: Sven Peter <sven@kernel.org>

Author: jannau

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

@@ -22,6 +22,25 @@
 	};
 };
 
+/*
+ * Keep the power-domains used for the HDMI port on.
+ */
+&framebuffer0 {
+	power-domains = <&ps_dispext_cpu0>, <&ps_dptx_ext_phy>;
+};
+
+/*
+ * The M2 Mac mini uses dispext for the HDMI output so it's not necessary to
+ * keep disp0 power-domains always-on.
+ */
+&ps_disp0_sys {
+	/delete-property/ apple,always-on;
+};
+
+&ps_disp0_fe {
+	/delete-property/ apple,always-on;
+};
+
 /*
  * Force the bus number assignments so that we can declare some of the
  * on-board devices and properties that are populated by the bootloader