dt-bindings: display: rockchip: Add binding for VOP2

The VOP2 is found on newer Rockchip SoCs like the rk3568 or the rk3566.
The binding differs slightly from the existing VOP binding, so add a new
binding file for it.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Tested-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220422072841.2206452-24-s.hauer@pengutronix.de

Documentation/devicetree/bindings/display/rockchip/rockchip-vop2.yaml

+# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/rockchip/rockchip-vop2.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Rockchip SoC display controller (VOP2)
+
+description:
+  VOP2 (Video Output Processor v2) is the display controller for the Rockchip
+  series of SoCs which transfers the image data from a video memory
+  buffer to an external LCD interface.
+
+maintainers:
+  - Sandy Huang <hjc@rock-chips.com>
+  - Heiko Stuebner <heiko@sntech.de>
+
+properties:
+  compatible:
+    enum:
+      - rockchip,rk3566-vop
+      - rockchip,rk3568-vop
+
+  reg:
+    minItems: 1
+    items:
+      - description:
+          Must contain one entry corresponding to the base address and length
+          of the register space.
+      - description:
+          Can optionally contain a second entry corresponding to
+          the CRTC gamma LUT address.
+
+  interrupts:
+    maxItems: 1
+    description:
+      The VOP interrupt is shared by several interrupt sources, such as
+      frame start (VSYNC), line flag and other status interrupts.
+
+  clocks:
+    items:
+      - description: Clock for ddr buffer transfer.
+      - description: Clock for the ahb bus to R/W the phy regs.
+      - description: Pixel clock for video port 0.
+      - description: Pixel clock for video port 1.
+      - description: Pixel clock for video port 2.
+
+  clock-names:
+    items:
+      - const: aclk
+      - const: hclk
+      - const: dclk_vp0
+      - const: dclk_vp1
+      - const: dclk_vp2
+
+  rockchip,grf:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to GRF regs used for misc control
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/properties/port
+        description:
+          Output endpoint of VP0
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description:
+          Output endpoint of VP1
+
+      port@2:
+        $ref: /schemas/graph.yaml#/properties/port
+        description:
+          Output endpoint of VP2
+
+  iommus:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+        #include <dt-bindings/clock/rk3568-cru.h>
+        #include <dt-bindings/interrupt-controller/arm-gic.h>
+        #include <dt-bindings/power/rk3568-power.h>
+        bus {
+            #address-cells = <2>;
+            #size-cells = <2>;
+            vop: vop@fe040000 {
+                compatible = "rockchip,rk3568-vop";
+                reg = <0x0 0xfe040000 0x0 0x3000>, <0x0 0xfe044000 0x0 0x1000>;
+                interrupts = <GIC_SPI 148 IRQ_TYPE_LEVEL_HIGH>;
+                clocks = <&cru ACLK_VOP>,
+                         <&cru HCLK_VOP>,
+                         <&cru DCLK_VOP0>,
+                         <&cru DCLK_VOP1>,
+                         <&cru DCLK_VOP2>;
+                clock-names = "aclk",
+                              "hclk",
+                              "dclk_vp0",
+                              "dclk_vp1",
+                              "dclk_vp2";
+                power-domains = <&power RK3568_PD_VO>;
+                iommus = <&vop_mmu>;
+                vop_out: ports {
+                    #address-cells = <1>;
+                    #size-cells = <0>;
+                    vp0: port@0 {
+                        reg = <0>;
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                    };
+                    vp1: port@1 {
+                        reg = <1>;
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                    };
+                    vp2: port@2 {
+                        reg = <2>;
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                    };
+                };
+            };
+        };