Documentation: DT: Add bindings documentation for Gamma LUT IP

This commit adds device tree bindings for the Xilinx Video
Gamma Correction LUT IP

Signed-off-by: Rohit Athavale <rathaval@xilinx.com>

1 files changed, 74 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/media/xilinx/xlnx,v-gamma-lut-v1.0.txt b/Documentation/devicetree/bindings/media/xilinx/xlnx,v-gamma-lut-v1.0.txt
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+Xilinx Video Gamma Correction IP
+------------------------------------------------
+The Xilinx Video Gamma Correction IP is used to provide RGB gamma correction.
+The IP provides a look up table for each R,G and B components.
+
+It takes an a 24bit RBG streaming input and provides a gamma corrected 24 bit RGB format.
+Currently, the driver supports only the following configurations :
+	- 8 bit (bits per pixel)
+
+All other configurations are not supported.
+
+The V4L2 subdevice driver exposes a control interface through which you can specify
+gamma values for R,G and B components individually.
+
+Example :
+A value of  1 represents a gamma of 0.1
+A value of 10 represents a gamma of 1.0 (default)
+A value of 40 represents a gamma of 4.0 (maximum)
+
+Note : A gamma of value 1.0 is a linear curve or pass through design, with
+no corrective action.
+
+Required properties:
+
+- compatible: Must be "xlnx,v-gamma-lut-v1.0".
+
+- reg: Physical base address and length of the registers set for the device.
+
+- clocks: Reference to the video core clock.
+
+- reset-gpios: Specifier for a GPIO that assert gamma IP (AP_RST_N) reset.
+
+- ports: Video ports, using the DT bindings defined in ../video-interfaces.txt.
+  The scaler has an input port (0) and an output port (1).
+
+
+Required port properties:
+- reg: This value represents the media pad of the V4L2 sub-device.
+  A Sink Pad is represented by reg = <0>
+  A Source Pad is represented by reg = <1>
+
+- xlnx,video-width: Video width as defined in video.txt
+
+
+Example :
+
+	gamma_lut_1: gamma_lut_1@0xa0080000 {
+		compatible = "xlnx,v-gamma-lut-v1.0";
+		reg = <0x0 0xa0080000 0x0 0x10000>;
+		clocks = <&vid_stream_clk>;
+		reset-gpios = <&gpio 83 1>;
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
+				reg = <0>;
+				xlnx,video-width = <8>;
+
+				gamma_in: endpoint {
+					remote-endpoint = <&demosaic_out>;
+				};
+			};
+
+			port@1 {
+				reg = <1>;
+				xlnx,video-width = <8>;
+
+				gamma_out: endpoint {
+					remote-endpoint = <&csc_in>;
+				};
+			};
+		};
+	};