[PATCH/RFC 1/1] arm64: dts: renesas: white-hawk: Add mini-DP output support

[Geert Uytterhoeven <geert+renesas@xxxxxxxxx>]

Add support for the mini-DisplayPort connector on the White Hawk
BreakOut board.  This port is driven by a TI SN65DSI86 DSI to eDP
bridge, which in turn gets the pixel data from the second DSI channel on
the R-Car V4H SoC.  Note that this port is not present on the White Hawk
Single development board.

Based on the work by Tomi Valkeinen for the mini-DP port on the White
Hawk CPU board, and by a patch in the BSP by LUU HOAI.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
This has a hard dependency on "[PATCH] drm/bridge: ti-sn65dsi86: Fix
multiple instances"[1], as the rcar-du driver fails to probe when any of
the encoders failed to initialize:

    platform feb00000.display: deferred probe pending: rcar-du: failed to initialize encoders

Does not work:
  - Display resolution is detected correctly (1920x1080 or 2560x1440),
  - Black screen, displays say no signal detected,
  - "modetest -M rcar-du -s 88:1920x1080@XR24" triggers:

	rcar-mipi-dsi fed90000.dsi-encoder: Failed to disable video transmission
	vsp1 fea20000.vsp: Underrun occurred at WPF0 (total underruns 2)

    Note that fea20000.vsp is vspd0, not vspd1. I do have a few similar
    messages for fea28000.vsp in my logs, so this may be a red herring.

[1] https://lore.kernel.org/8c2df6a903f87d4932586b25f1d3bd548fe8e6d1.1729180470.git.geert+renesas@xxxxxxxxx/
---
 .../boot/dts/renesas/r8a779g0-white-hawk.dts  | 90 +++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r8a779g0-white-hawk.dts b/arch/arm64/boot/dts/renesas/r8a779g0-white-hawk.dts
index 784d4e8b204ce85a..cb84fe5e9eea1f2f 100644
--- a/arch/arm64/boot/dts/renesas/r8a779g0-white-hawk.dts
+++ b/arch/arm64/boot/dts/renesas/r8a779g0-white-hawk.dts
@@ -12,4 +12,94 @@
 / {
 	model = "Renesas White Hawk CPU and Breakout boards based on r8a779g0";
 	compatible = "renesas,white-hawk-breakout", "renesas,white-hawk-cpu", "renesas,r8a779g0";
+
+	sn65dsi86_refclk2: clk-x16 {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <38400000>;
+	};
+
+	mini-dp-con2 {
+		compatible = "dp-connector";
+		label = "CN15";
+		type = "mini";
+
+		port {
+			mini_dp_con_in2: endpoint {
+				remote-endpoint = <&sn65dsi86_out2>;
+			};
+		};
+	};
+};
+
+&dsi1 {
+	status = "okay";
+
+	ports {
+		port@1 {
+			dsi1_out: endpoint {
+				remote-endpoint = <&sn65dsi86_in2>;
+				data-lanes = <1 2 3 4>;
+			};
+		};
+	};
+};
+
+&i2c4 {
+	pinctrl-0 = <&i2c4_pins>;
+	pinctrl-names = "default";
+
+	status = "okay";
+	clock-frequency = <400000>;
+
+	bridge@2c {
+		pinctrl-0 = <&irq1_pins>;
+		pinctrl-names = "default";
+
+		compatible = "ti,sn65dsi86";
+		reg = <0x2c>;
+
+		clocks = <&sn65dsi86_refclk2>;
+		clock-names = "refclk";
+
+		interrupts-extended = <&intc_ex 1 IRQ_TYPE_LEVEL_HIGH>;
+
+		enable-gpios = <&gpio1 27 GPIO_ACTIVE_HIGH>;
+
+		vccio-supply = <&reg_1p8v>;
+		vpll-supply = <&reg_1p8v>;
+		vcca-supply = <&reg_1p2v>;
+		vcc-supply = <&reg_1p2v>;
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
+				reg = <0>;
+				sn65dsi86_in2: endpoint {
+					remote-endpoint = <&dsi1_out>;
+				};
+			};
+
+			port@1 {
+				reg = <1>;
+				sn65dsi86_out2: endpoint {
+					remote-endpoint = <&mini_dp_con_in2>;
+				};
+			};
+		};
+	};
+};
+
+&pfc {
+	i2c4_pins: i2c4 {
+		groups = "i2c4";
+		function = "i2c4";
+	};
+
+	irq1_pins: irq1 {
+		groups = "intc_ex_irq1_a";
+		function = "intc_ex";
+	};
 };
-- 
2.34.1