dt-bindings: display: xlnx: Add ZynqMP DP subsystem bindings

The bindings describe the ZynqMP DP subsystem. They don't support the
interface with the programmable logic (FPGA) or audio yet.
Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>

Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/xlnx/xlnx,zynqmp-dpsub.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xilinx ZynqMP DisplayPort Subsystem
+
+description: |
+  The DisplayPort subsystem of Xilinx ZynqMP (Zynq UltraScale+ MPSoC)
+  implements the display and audio pipelines based on the DisplayPort v1.2
+  standard. The subsystem includes multiple functional blocks as below:
+
+               +------------------------------------------------------------+
+  +--------+   | +----------------+     +-----------+                       |
+  | DPDMA  | --->|                | --> |   Video   | Video +-------------+ |
+  | 4x vid |   | |                |     | Rendering | -+--> |             | |   +------+
+  | 2x aud |   | |  Audio/Video   | --> | Pipeline  |  |    | DisplayPort |---> | PHY0 |
+  +--------+   | | Buffer Manager |     +-----------+  |    |   Source    | |   +------+
+               | |    and STC     |     +-----------+  |    | Controller  | |   +------+
+  Live Video --->|                | --> |   Audio   | Audio |             |---> | PHY1 |
+               | |                |     |   Mixer   | --+-> |             | |   +------+
+  Live Audio --->|                | --> |           |  ||   +-------------+ |
+               | +----------------+     +-----------+  ||                   |
+               +---------------------------------------||-------------------+
+                                                       vv
+                                                 Blended Video and
+                                                 Mixed Audio to PL
+
+  The Buffer Manager interacts with external interface such as DMA engines or
+  live audio/video streams from the programmable logic. The Video Rendering
+  Pipeline blends the video and graphics layers and performs colorspace
+  conversion. The Audio Mixer mixes the incoming audio streams. The DisplayPort
+  Source Controller handles the DisplayPort protocol and connects to external
+  PHYs.
+
+  The subsystem supports 2 video and 2 audio streams, and various pixel formats
+  and depths up to 4K@30 resolution.
+
+  Please refer to "Zynq UltraScale+ Device Technical Reference Manual"
+  (https://www.xilinx.com/support/documentation/user_guides/ug1085-zynq-ultrascale-trm.pdf)
+  for more details.
+
+maintainers:
+  - Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+
+properties:
+  compatible:
+    const: xlnx,zynqmp-dpsub-1.7
+
+  reg:
+    maxItems: 4
+  reg-names:
+    items:
+      - const: dp
+      - const: blend
+      - const: av_buf
+      - const: aud
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description:
+      The APB clock and at least one video clock are mandatory, the audio clock
+      is optional.
+    minItems: 2
+    maxItems: 4
+    items:
+      - description: dp_apb_clk is the APB clock
+      - description: dp_aud_clk is the Audio clock
+      - description:
+          dp_vtc_pixel_clk_in is the non-live video clock (from Processing
+          System)
+      - description:
+          dp_live_video_in_clk is the live video clock (from Programmable
+          Logic)
+  clock-names:
+    oneOf:
+      - minItems: 2
+        maxItems: 3
+        items:
+          - const: dp_apb_clk
+          - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
+          - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
+      - minItems: 3
+        maxItems: 4
+        items:
+          - const: dp_apb_clk
+          - const: dp_aud_clk
+          - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
+          - enum: [ dp_vtc_pixel_clk_in, dp_live_video_in_clk ]
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  dmas:
+    maxItems: 4
+    items:
+      - description: Video layer, plane 0 (RGB or luma)
+      - description: Video layer, plane 1 (U/V or U)
+      - description: Video layer, plane 2 (V)
+      - description: Graphics layer
+  dma-names:
+    items:
+      - const: vid0
+      - const: vid1
+      - const: vid2
+      - const: gfx0
+
+  phys:
+    description: PHYs for the DP data lanes
+    minItems: 1
+    maxItems: 2
+  phy-names:
+    minItems: 1
+    maxItems: 2
+    items:
+      - const: dp-phy0
+      - const: dp-phy1
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - clocks
+  - clock-names
+  - power-domains
+  - resets
+  - dmas
+  - dma-names
+  - phys
+  - phy-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/phy/phy.h>
+    #include <dt-bindings/reset/xlnx-zynqmp-resets.h>
+
+    display@fd4a0000 {
+        compatible = "xlnx,zynqmp-dpsub-1.7";
+        reg = <0x0 0xfd4a0000 0x0 0x1000>,
+              <0x0 0xfd4aa000 0x0 0x1000>,
+              <0x0 0xfd4ab000 0x0 0x1000>,
+              <0x0 0xfd4ac000 0x0 0x1000>;
+        reg-names = "dp", "blend", "av_buf", "aud";
+        interrupts = <0 119 4>;
+        interrupt-parent = <&gic>;
+
+        clock-names = "dp_apb_clk", "dp_aud_clk", "dp_live_video_in_clk";
+        clocks = <&dp_aclk>, <&clkc 17>, <&si570_1>;
+
+        power-domains = <&pd_dp>;
+        resets = <&reset ZYNQMP_RESET_DP>;
+
+        dma-names = "vid0", "vid1", "vid2", "gfx0";
+        dmas = <&xlnx_dpdma 0>,
+               <&xlnx_dpdma 1>,
+               <&xlnx_dpdma 2>,
+               <&xlnx_dpdma 3>;
+
+        phys = <&psgtr 1 PHY_TYPE_DP 0 3 27000000>,
+               <&psgtr 0 PHY_TYPE_DP 1 3 27000000>;
+
+        phy-names = "dp-phy0", "dp-phy1";
+    };
+
+...