dt-bindings: media: Add bindings for bcm2835-unicam

Introduce the dt-bindings documentation for bcm2835 CCP2/CSI2 Unicam
camera interface.

Signed-off-by: Dave Stevenson <[e-mail]>
Co-developed-by: Naushir Patuck <[e-mail]>
Signed-off-by: Naushir Patuck <[e-mail]>
Co-developed-by: Jean-Michel Hautbois <[e-mail]>
Signed-off-by: Jean-Michel Hautbois <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Sakari Ailus <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/brcm,bcm2835-unicam.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom BCM283x Camera Interface (Unicam)
+
+maintainers:
+  - Raspberry Pi Kernel Maintenance <[e-mail]>
+
+description: |-
+  The Unicam block on BCM283x SoCs is the receiver for either
+  CSI-2 or CCP2 data from image sensors or similar devices.
+
+  The main platform using this SoC is the Raspberry Pi family of boards.  On
+  the Pi the VideoCore firmware can also control this hardware block, and
+  driving it from two different processors will cause issues.  To avoid this,
+  the firmware checks the device tree configuration during boot. If it finds
+  device tree nodes whose name starts with 'csi' then it will stop the firmware
+  accessing the block, and it can then safely be used via the device tree
+  binding.
+
+properties:
+  compatible:
+    const: brcm,bcm2835-unicam
+
+  reg:
+    items:
+      - description: Unicam block.
+      - description: Clock Manager Image (CMI) block.
+
+  reg-names:
+    items:
+      - const: unicam
+      - const: cmi
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Clock to drive the LP state machine of Unicam.
+      - description: Clock for the VPU (core clock).
+
+  clock-names:
+    items:
+      - const: lp
+      - const: vpu
+
+  power-domains:
+    items:
+      - description: Unicam power domain
+
+  brcm,num-data-lanes:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [ 2, 4 ]
+    description: |
+      Number of CSI-2 data lanes supported by this Unicam instance. The number
+      of data lanes actively used is specified with the data-lanes endpoint
+      property.
+
+  port:
+    $ref: /schemas/graph.yaml#/$defs/port-base
+    unevaluatedProperties: false
+
+    properties:
+      endpoint:
+        $ref: /schemas/media/video-interfaces.yaml#
+        additionalProperties: false
+
+        properties:
+          bus-type:
+            enum: [ 3, 4 ]
+
+          clock-noncontinuous: true
+          data-lanes: true
+          remote-endpoint: true
+
+        required:
+          - bus-type
+          - data-lanes
+          - remote-endpoint
+
+    required:
+      - endpoint
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - clocks
+  - clock-names
+  - power-domains
+  - brcm,num-data-lanes
+  - port
+
+additionalProperties: False
+
+examples:
+  - |
+    #include <dt-bindings/clock/bcm2835.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/media/video-interfaces.h>
+    #include <dt-bindings/power/raspberrypi-power.h>
+
+    csi1: csi@7e801000 {
+        compatible = "brcm,bcm2835-unicam";
+        reg = <0x7e801000 0x800>,
+              <0x7e802004 0x4>;
+        reg-names = "unicam", "cmi";
+        interrupts = <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&clocks BCM2835_CLOCK_CAM1>,
+                 <&firmware_clocks 4>;
+        clock-names = "lp", "vpu";
+        power-domains = <&power RPI_POWER_DOMAIN_UNICAM1>;
+        brcm,num-data-lanes = <2>;
+        port {
+                csi1_ep: endpoint {
+                        remote-endpoint = <&imx219_0>;
+                        bus-type = <MEDIA_BUS_TYPE_CSI2_DPHY>;
+                        data-lanes = <1 2>;
+                };
+        };
+    };
+...

MAINTAINERS

···
 N:	bcm216*
 N:	kona
 
+BROADCOM BCM2835 CAMERA DRIVERS
+M:	Raspberry Pi Kernel Maintenance <[e-mail]>
+L:	[e-mail]
+S:	Maintained
+F:	Documentation/devicetree/bindings/media/brcm,bcm2835-unicam.yaml
+
 BROADCOM BCM47XX MIPS ARCHITECTURE
 M:	Hauke Mehrtens <[e-mail]>
 M:	Rafał Miłecki <[e-mail]>