media: dt-bindings: media: atmel: csi2dc: add bindings for microchip csi2dc

Add bindings documentation for Microchip CSI2 Demultiplexer controller.

CSI2DC is a demultiplexer from Synopsys IDI interface specification to
parallel interface connection or direct memory access.
CSI2DC can also act as a parallel bypass from a parallel sensor to the
image sensor controller/interface.
Signed-off-by: NEugen Hristev <eugen.hristev@microchip.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@kernel.org>

Documentation/devicetree/bindings/media/microchip,csi2dc.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/microchip,csi2dc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip CSI2 Demux Controller (CSI2DC)
+
+maintainers:
+  - Eugen Hristev <eugen.hristev@microchip.com>
+
+description:
+  CSI2DC - Camera Serial Interface 2 Demux Controller
+
+  CSI2DC is a hardware block that receives incoming data from either from an
+  IDI interface or from a parallel bus interface.
+  It filters IDI packets based on their data type and virtual channel
+  identifier, then converts the byte stream to a pixel stream into a cross
+  clock domain towards a parallel interface that can be read by a sensor
+  controller.
+  IDI interface is Synopsys proprietary.
+  CSI2DC can act a simple bypass bridge if the incoming data is coming from
+  a parallel interface.
+
+  CSI2DC provides two pipes, one video pipe and one data pipe. Video pipe
+  is connected at the output to a sensor controller and the data pipe is
+  accessible as a DMA slave port to a DMA controller.
+
+  CSI2DC supports a single 'port' node as a sink port with either Synopsys
+  32-bit IDI interface or a parallel interface.
+
+  CSI2DC supports one 'port' node as source port with parallel interface.
+  This is called video pipe.
+  This port has an 'endpoint' that can be connected to a sink port of another
+  controller (next in pipeline).
+
+  CSI2DC also supports direct access to the data through AHB, via DMA channel,
+  called data pipe.
+  For data pipe to be available, a dma controller and a dma channel must be
+  referenced.
+
+properties:
+  compatible:
+    const: microchip,sama7g5-csi2dc
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    minItems: 2
+    maxItems: 2
+
+  clock-names:
+    description:
+      CSI2DC must have two clocks to function correctly. One clock is the
+      peripheral clock for the inside functionality of the hardware block.
+      This is named 'pclk'. The second clock must be the cross domain clock,
+      in which CSI2DC will perform clock crossing. This clock must be fed
+      by the next controller in pipeline, which usually is a sensor controller.
+      Normally this clock should be given by this sensor controller who
+      is also a clock source. This clock is named 'scck', sensor controller clock.
+    items:
+      - const: pclk
+      - const: scck
+
+  dmas:
+    maxItems: 1
+
+  dma-names:
+    const: rx
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        description:
+          Input port node, single endpoint describing the input port.
+
+        properties:
+          endpoint:
+            $ref: video-interfaces.yaml#
+            unevaluatedProperties: false
+            description: Endpoint connected to input device
+
+            properties:
+              bus-type:
+                enum: [4, 5, 6]
+                default: 4
+
+              bus-width:
+                enum: [8, 9, 10, 11, 12, 13, 14]
+                default: 14
+
+              clock-noncontinuous:
+                type: boolean
+                description:
+                  Presence of this boolean property decides whether clock is
+                  continuous or noncontinuous.
+
+              remote-endpoint: true
+
+      port@1:
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        description:
+          Output port node, single endpoint describing the output port.
+
+        properties:
+          endpoint:
+            unevaluatedProperties: false
+            $ref: video-interfaces.yaml#
+            description: Endpoint connected to output device
+
+            properties:
+              bus-type:
+                enum: [5, 6]
+                default: 5
+
+              bus-width:
+                enum: [8, 9, 10, 11, 12, 13, 14]
+                default: 14
+
+              remote-endpoint: true
+
+    required:
+      - port@0
+      - port@1
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - ports
+
+examples:
+  # Example for connecting to a parallel sensor controller block (video pipe)
+  # and the input is received from Synopsys IDI interface
+  - |
+    csi2dc@e1404000 {
+        compatible = "microchip,sama7g5-csi2dc";
+        reg = <0xe1404000 0x500>;
+        clocks = <&pclk>, <&scck>;
+        clock-names = "pclk", "scck";
+
+        ports {
+               #address-cells = <1>;
+               #size-cells = <0>;
+               port@0 {
+                       reg = <0>; /* must be 0, first child port */
+                       csi2dc_in: endpoint { /* input from IDI interface */
+                               bus-type = <4>; /* MIPI CSI2 D-PHY */
+                               remote-endpoint = <&csi2host_out>;
+                       };
+               };
+
+               port@1 {
+                       reg = <1>; /* must be 1, second child port */
+                       csi2dc_out: endpoint {
+                               remote-endpoint = <&xisc_in>; /* output to sensor controller */
+                       };
+               };
+        };
+    };
+
+  # Example for connecting to a DMA master as an AHB slave
+  # and the input is received from Synopsys IDI interface
+  - |
+    #include <dt-bindings/dma/at91.h>
+    csi2dc@e1404000 {
+        compatible = "microchip,sama7g5-csi2dc";
+        reg = <0xe1404000 0x500>;
+        clocks = <&pclk>, <&scck>;
+        clock-names = "pclk", "scck";
+        dmas = <&dma0 AT91_XDMAC_DT_PERID(34)>;
+        dma-names = "rx";
+
+        ports {
+               #address-cells = <1>;
+               #size-cells = <0>;
+               port@0 {
+                       reg = <0>; /* must be 0, first child port */
+                       csi2dc_input: endpoint { /* input from IDI interface */
+                               remote-endpoint = <&csi2host_out>;
+                       };
+               };
+
+               port@1 {
+                       reg = <1>;
+               };
+        };
+    };
+
+...