media: dt-bindings: Convert Omnivision OV7251 to DT schema

Convert the OmniVision OV7251 Image Sensor binding to DT schema format.

vddd-supply was listed as required, but the example and actual user
don't have it. Also, the data brief says it has an internal regulator,
so perhaps it is truly optional.

Add missing common "link-frequencies" which is used and required by the
Linux driver.
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C
Link: https://lore.kernel.org/r/20230817202713.2180195-1-robh@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/i2c/qcom,i2c-cci.yaml

@@ -269,6 +269,7 @@ examples:
                 port {
                     ov7251_ep: endpoint {
                         data-lanes = <0 1>;
+                        link-frequencies = /bits/ 64 <240000000 319200000>;
                         remote-endpoint = <&csiphy3_ep>;
                     };
                 };

Documentation/devicetree/bindings/media/i2c/ov7251.txt

-* Omnivision 1/7.5-Inch B&W VGA CMOS Digital Image Sensor
-
-The Omnivision OV7251 is a 1/7.5-Inch CMOS active pixel digital image sensor
-with an active array size of 640H x 480V. It is programmable through a serial
-I2C interface.
-
-Required Properties:
-- compatible: Value should be "ovti,ov7251".
-- clocks: Reference to the xclk clock.
-- clock-names: Should be "xclk".
-- clock-frequency: Frequency of the xclk clock.
-- enable-gpios: Chip enable GPIO. Polarity is GPIO_ACTIVE_HIGH. This corresponds
-  to the hardware pin XSHUTDOWN which is physically active low.
-- vdddo-supply: Chip digital IO regulator.
-- vdda-supply: Chip analog regulator.
-- vddd-supply: Chip digital core regulator.
-
-The device node shall contain one 'port' child node with a single 'endpoint'
-subnode for its digital output video port, in accordance with the video
-interface bindings defined in
-Documentation/devicetree/bindings/media/video-interfaces.txt.
-
-Example:
-
-	&i2c1 {
-		...
-
-		ov7251: camera-sensor@60 {
-			compatible = "ovti,ov7251";
-			reg = <0x60>;
-
-			enable-gpios = <&gpio1 6 GPIO_ACTIVE_HIGH>;
-			pinctrl-names = "default";
-			pinctrl-0 = <&camera_bw_default>;
-
-			clocks = <&clks 200>;
-			clock-names = "xclk";
-			clock-frequency = <24000000>;
-
-			vdddo-supply = <&camera_dovdd_1v8>;
-			vdda-supply = <&camera_avdd_2v8>;
-			vddd-supply = <&camera_dvdd_1v2>;
-
-			port {
-				ov7251_ep: endpoint {
-					clock-lanes = <1>;
-					data-lanes = <0>;
-					remote-endpoint = <&csi0_ep>;
-				};
-			};
-		};
-	};

Documentation/devicetree/bindings/media/i2c/ovti,ov7251.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/i2c/ovti,ov7251.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: OmniVision OV7251 Image Sensor
+
+description:
+  The Omnivision OV7251 is a 1/7.5-Inch CMOS active pixel digital image sensor
+  with an active array size of 640H x 480V. It is programmable through a serial
+  I2C interface.
+
+maintainers:
+  - Todor Tomov <todor.too@gmail.com>
+
+properties:
+  compatible:
+    const: ovti,ov7251
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    description: XCLK Input Clock
+
+  clock-names:
+    const: xclk
+
+  clock-frequency:
+    description: Frequency of the xclk clock in Hz.
+
+  vdda-supply:
+    description: Analog voltage supply, 2.8 volts
+
+  vddd-supply:
+    description: Digital core voltage supply, 1.2 volts
+
+  vdddo-supply:
+    description: Digital I/O voltage supply, 1.8 volts
+
+  enable-gpios:
+    maxItems: 1
+    description:
+      Reference to the GPIO connected to the XSHUTDOWN pin, if any. Polarity
+      is GPIO_ACTIVE_HIGH.
+
+  port:
+    description: Digital Output Port
+    $ref: /schemas/graph.yaml#/$defs/port-base
+    additionalProperties: false
+
+    properties:
+      endpoint:
+        $ref: /schemas/media/video-interfaces.yaml#
+        unevaluatedProperties: false
+
+        properties:
+          clock-lanes:
+            maximum: 1
+
+          data-lanes:
+            maxItems: 1
+
+          link-frequencies: true
+
+        required:
+          - data-lanes
+          - link-frequencies
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - vdddo-supply
+  - vdda-supply
+  - port
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        camera@3c {
+            compatible = "ovti,ov7251";
+            reg = <0x3c>;
+            clocks = <&clks 1>;
+            clock-frequency = <24000000>;
+            vdddo-supply = <&ov7251_vdddo_1v8>;
+            vdda-supply = <&ov7251_vdda_2v8>;
+            vddd-supply = <&ov7251_vddd_1v5>;
+            enable-gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>;
+
+            port {
+                ov7251_ep: endpoint {
+                    remote-endpoint = <&csi0_ep>;
+                    clock-lanes = <1>;
+                    data-lanes = <0>;
+                    link-frequencies = /bits/ 64 <240000000 319200000>;
+                };
+            };
+        };
+    };
+...