[media] v4l: vsp1: Add DT bindings documentation

All parameters supplied through platform data can now be passed through
the device tree.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

Documentation/devicetree/bindings/media/renesas,vsp1.txt

+* Renesas VSP1 Video Processing Engine
+
+The VSP1 is a video processing engine that supports up-/down-scaling, alpha
+blending, color space conversion and various other image processing features.
+It can be found in the Renesas R-Car second generation SoCs.
+
+Required properties:
+
+  - compatible: Must contain "renesas,vsp1"
+
+  - reg: Base address and length of the registers block for the VSP1.
+  - interrupts: VSP1 interrupt specifier.
+  - clocks: A phandle + clock-specifier pair for the VSP1 functional clock.
+
+  - renesas,#rpf: Number of Read Pixel Formatter (RPF) modules in the VSP1.
+  - renesas,#uds: Number of Up Down Scaler (UDS) modules in the VSP1.
+  - renesas,#wpf: Number of Write Pixel Formatter (WPF) modules in the VSP1.
+
+
+Optional properties:
+
+  - renesas,has-lif: Boolean, indicates that the LCD Interface (LIF) module is
+    available.
+  - renesas,has-lut: Boolean, indicates that the Look Up Table (LUT) module is
+    available.
+  - renesas,has-sru: Boolean, indicates that the Super Resolution Unit (SRU)
+    module is available.
+
+
+Example: R8A7790 (R-Car H2) VSP1-S node
+
+	vsp1@fe928000 {
+		compatible = "renesas,vsp1";
+		reg = <0 0xfe928000 0 0x8000>;
+		interrupts = <0 267 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&mstp1_clks R8A7790_CLK_VSP1_S>;
+
+		renesas,has-lut;
+		renesas,has-sru;
+		renesas,#rpf = <5>;
+		renesas,#uds = <3>;
+		renesas,#wpf = <4>;
+	};