Add bindings documentation for Xilinx MIPI CSI-2 Rx Subsystem.

The Xilinx MIPI CSI-2 Rx Subsystem consists of a CSI-2 Rx controller, a
D-PHY in Rx mode and a Video Format Bridge.

Signed-off-by: Vishal Sagar <redacted>
Reviewed-by: Hyun Kwon <redacted>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
v14
- Removed xlnx,csi-pxl-format from required properties
- Added dependency of xlnx,csi-pxl-format on xlnx,vfb
- End the yaml file with ...
- Added Reviewed by Laurent

v13
- Based on Laurent's suggestions
- Fixed the datatypes values as minimum and maximum
- condition added for en-vcx property

v12
- Moved to yaml format
- Update CSI-2 and D-PHY
- Mention that bindings for D-PHY not here
- reset -> video-reset

v11
- Modify compatible string from 4.0 to 5.0

v10
- No changes

v9
- Fix xlnx,vfb description.
- s/Optional/Required endpoint property.
- Move data-lanes description from Ports to endpoint property section.

v8
- Added reset-gpios optional property to assert video_aresetn

v7
- Removed the control name from dt bindings
- Updated the example dt node name to csi2rx

v6
- Added "control" after V4L2_CID_XILINX_MIPICSISS_ACT_LANES as suggested by Luca
- Added reviewed by Rob Herring

v5
- Incorporated comments by Luca Cersoli
- Removed DPHY clock from description and example
- Removed bayer pattern from device tree MIPI CSI IP
  doesn't deal with bayer pattern.

v4
- Added reviewed by Hyun Kwon

v3
- removed interrupt parent as suggested by Rob
- removed dphy clock
- moved vfb to optional properties
- Added required and optional port properties section
- Added endpoint property section

v2
- updated the compatible string to latest version supported
- removed DPHY related parameters
- added CSI v2.0 related property (including VCX for supporting upto 16
  virtual channels).
- modified csi-pxl-format from string to unsigned int type where the value
  is as per the CSI specification
- Defined port 0 and port 1 as sink and source ports.
- Removed max-lanes property as suggested by Rob and Sakari

 .../bindings/media/xilinx/xlnx,csi2rxss.yaml       | 237 +++++++++++++++++++++
 1 file changed, 237 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.yaml

diff --git a/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.yaml b/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.yaml
new file mode 100644
index 0000000..2282231
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.yaml

@@ -0,0 +1,237 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/xilinx/xlnx,csi2rxss.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xilinx MIPI CSI-2 Receiver Subsystem
+
+maintainers:
+  - Vishal Sagar <vishal.sagar@xilinx.com>
+
+description: |
+  The Xilinx MIPI CSI-2 Receiver Subsystem is used to capture MIPI CSI-2
+  traffic from compliant camera sensors and send the output as AXI4 Stream
+  video data for image processing.
+  The subsystem consists of a MIPI D-PHY in slave mode which captures the
+  data packets. This is passed along the MIPI CSI-2 Rx IP which extracts the
+  packet data. The optional Video Format Bridge (VFB) converts this data to
+  AXI4 Stream video data.
+  For more details, please refer to PG232 Xilinx MIPI CSI-2 Receiver Subsystem.
+  Please note that this bindings includes only the MIPI CSI-2 Rx controller
+  and Video Format Bridge and not D-PHY.
+
+properties:
+  compatible:
+    items:
+      - enum:
+        - xlnx,mipi-csi2-rx-subsystem-5.0
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: List of clock specifiers
+    items:
+      - description: AXI Lite clock
+      - description: Video clock
+
+  clock-names:
+    items:
+      - const: lite_aclk
+      - const: video_aclk
+
+  xlnx,csi-pxl-format:
+    description: |
+      This denotes the CSI Data type selected in hw design.
+      Packets other than this data type (except for RAW8 and
+      User defined data types) will be filtered out.
+      Possible values are as below -
+      0x1e - YUV4228B
+      0x1f - YUV42210B
+      0x20 - RGB444
+      0x21 - RGB555
+      0x22 - RGB565
+      0x23 - RGB666
+      0x24 - RGB888
+      0x28 - RAW6
+      0x29 - RAW7
+      0x2a - RAW8
+      0x2b - RAW10
+      0x2c - RAW12
+      0x2d - RAW14
+      0x2e - RAW16
+      0x2f - RAW20
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - anyOf:
+        - minimum: 0x1e
+        - maximum: 0x24
+        - minimum: 0x28
+        - maximum: 0x2f
+
+  xlnx,vfb:
+    type: boolean
+    description: Present when Video Format Bridge is enabled in IP configuration
+
+  xlnx,en-csi-v2-0:
+    type: boolean
+    description: Present if CSI v2 is enabled in IP configuration.
+
+  xlnx,en-vcx:
+    type: boolean
+    description: |
+      When present, there are maximum 16 virtual channels, else only 4.
+
+  xlnx,en-active-lanes:
+    type: boolean
+    description: |
+      Present if the number of active lanes can be re-configured at
+      runtime in the Protocol Configuration Register. Otherwise all lanes,
+      as set in IP configuration, are always active.
+
+  video-reset-gpios:
+    description: Optional specifier for a GPIO that asserts video_aresetn.
+    maxItems: 1
+
+  ports:
+    type: object
+
+    properties:
+      port@0:
+        type: object
+        description: |
+          Input / sink port node, single endpoint describing the
+          CSI-2 transmitter.
+
+        properties:
+          reg:
+            const: 0
+
+          endpoint:
+            type: object
+
+            properties:
+
+              data-lanes:
+                description: |
+                  This is required only in the sink port 0 endpoint which
+                  connects to MIPI CSI-2 source like sensor.
+                  The possible values are -
+                  1       - For 1 lane enabled in IP.
+                  1 2     - For 2 lanes enabled in IP.
+                  1 2 3   - For 3 lanes enabled in IP.
+                  1 2 3 4 - For 4 lanes enabled in IP.
+                items:
+                  - const: 1
+                  - const: 2
+                  - const: 3
+                  - const: 4
+
+              remote-endpoint: true
+
+            required:
+              - data-lanes
+              - remote-endpoint
+
+            additionalProperties: false
+
+        additionalProperties: false
+
+      port@1:
+        type: object
+        description: |
+          Output / source port node, endpoint describing modules
+          connected the CSI-2 receiver.
+
+        properties:
+
+          reg:
+            const: 1
+
+          endpoint:
+            type: object
+
+            properties:
+
+              remote-endpoint: true
+
+            required:
+              - remote-endpoint
+
+            additionalProperties: false
+
+        additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - ports
+
+allOf:
+  - if:
+    required:
+      - xlnx,vfb
+    then:
+      required:
+        - xlnx,csi-pxl-format
+    else:
+      properties:
+        xlnx,csi-pxl-format: false
+
+  - if:
+    not:
+      required:
+        - xlnx,en-csi-v2-0
+    then:
+      properties:
+        xlnx,en-vcx: false