[PATCH] arm64: dts: rockchip: odroid-m2: Enable DisplayPort Alt Mode over USB-C

[Clemens Malten]

Enable USB-C DisplayPort Alt Mode on the ODROID-M2 board (RK3588S) by
adding the necessary DTS changes:

- Enable dp0 controller (dw-dp driver)
- Add VOP2 video pipeline endpoints: vp2 -> dp0 -> usbdp_phy0
- Fix try-power-role from 'source' to 'sink' to allow the board to
  receive power and trigger correct PD negotiation
- Add altmodes block to the USB-C connector with DP SVID (0xff01) and
  VDO. Note: svid must be declared as a 16-bit value (/bits/ 16) as
  required by the typec class driver (fwnode_property_read_u16)

Tested on ODROID-M2 (RK3588S) with a UGreen CM654 USB-C DP adapter
under mainline Linux 6.19-rc.

This patch depends on Andy Yan's RK3588 DisplayPort Controller series:
Link: https://lore.kernel.org/all/20250822063959.692098-1-andyshrk@xxxxxxx/

Signed-off-by: Clemens Malten <c.malten@xxxxxxxxx>
---
 .../boot/dts/rockchip/rk3588s-odroid-m2.dts   | 29 ++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3588s-odroid-m2.dts b/arch/arm64/boot/dts/rockchip/rk3588s-odroid-m2.dts
index a72063c55..dbc62f032 100644
--- a/arch/arm64/boot/dts/rockchip/rk3588s-odroid-m2.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3588s-odroid-m2.dts
@@ -352,7 +352,17 @@ connector {
 			power-role = "dual";
 			sink-pdos = <PDO_FIXED(5000, 1000, PDO_FIXED_USB_COMM)>;
 			source-pdos = <PDO_FIXED(5000, 3000, PDO_FIXED_USB_COMM)>;
-			try-power-role = "source";
+			try-power-role = "sink";
+
+			altmodes {
+				#address-cells = <1>;
+				#size-cells = <0>;
+				altmode@0 {
+					reg = <0>;
+					svid = /bits/ 16 <0xff01>;
+					vdo = <0xffffffff>;
+				};
+			};
 
 			ports {
 				#address-cells = <1>;
@@ -952,3 +962,20 @@ vp0_out_hdmi0: endpoint@ROCKCHIP_VOP2_EP_HDMI0 {
 		remote-endpoint = <&hdmi0_in_vp0>;
 	};
 };
+
+&dp0 {
+	status = "okay";
+};
+
+&dp0_in {
+	dp0_in_vp2: endpoint {
+		remote-endpoint = <&vp2_out_dp0>;
+	};
+};
+
+&vp2 {
+	vp2_out_dp0: endpoint@a {
+		reg = <ROCKCHIP_VOP2_EP_DP0>;
+		remote-endpoint = <&dp0_in_vp2>;
+	};
+};
-- 
2.53.0