media: dt-bindings: media: add Amlogic Video Decoder Bindings

Add documentation for the meson vdec dts node.
Signed-off-by: Maxime Jourdan <mjourdan@baylibre.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/devicetree/bindings/media/amlogic,vdec.txt

+Amlogic Video Decoder
+================================
+
+The video decoding IP lies within the DOS memory region,
+except for the hardware bitstream parser that makes use of an undocumented
+region.
+
+It makes use of the following blocks:
+
+- ESPARSER is a bitstream parser that outputs to a VIFIFO. Further VDEC blocks
+then feed from this VIFIFO.
+- VDEC_1 can decode MPEG-1, MPEG-2, MPEG-4 part 2, MJPEG, H.263, H.264, VC-1.
+- VDEC_HEVC can decode HEVC and VP9.
+
+Both VDEC_1 and VDEC_HEVC share the "vdec" IRQ and as such cannot run
+concurrently.
+
+Device Tree Bindings:
+---------------------
+
+VDEC: Video Decoder
+--------------------------
+
+Required properties:
+- compatible: value should be different for each SoC family as :
+	- GXBB (S905) : "amlogic,gxbb-vdec"
+	- GXL (S905X, S905D) : "amlogic,gxl-vdec"
+	- GXM (S912) : "amlogic,gxm-vdec"
+- reg: base address and size of he following memory-mapped regions :
+	- dos
+	- esparser
+- reg-names: should contain the names of the previous memory regions
+- interrupts: should contain the following IRQs:
+	- vdec
+	- esparser
+- interrupt-names: should contain the names of the previous interrupts
+- amlogic,ao-sysctrl: should point to the AOBUS sysctrl node
+- amlogic,canvas: should point to a canvas provider node
+- clocks: should contain the following clocks :
+	- dos_parser
+	- dos
+	- vdec_1
+	- vdec_hevc
+- clock-names: should contain the names of the previous clocks
+- resets: should contain the parser reset
+- reset-names: should be "esparser"
+
+Example:
+
+vdec: video-decoder@c8820000 {
+	compatible = "amlogic,gxbb-vdec";
+	reg = <0x0 0xc8820000 0x0 0x10000>,
+	      <0x0 0xc110a580 0x0 0xe4>;
+	reg-names = "dos", "esparser";
+
+	interrupts = <GIC_SPI 44 IRQ_TYPE_EDGE_RISING>,
+		     <GIC_SPI 32 IRQ_TYPE_EDGE_RISING>;
+	interrupt-names = "vdec", "esparser";
+
+	amlogic,ao-sysctrl = <&sysctrl_AO>;
+	amlogic,canvas = <&canvas>;
+
+	clocks = <&clkc CLKID_DOS_PARSER>,
+		 <&clkc CLKID_DOS>,
+		 <&clkc CLKID_VDEC_1>,
+		 <&clkc CLKID_VDEC_HEVC>;
+	clock-names = "dos_parser", "dos", "vdec_1", "vdec_hevc";
+
+	resets = <&reset RESET_PARSER>;
+	reset-names = "esparser";
+};