media: dt-bindings: media: Add Amlogic Meson AO-CEC bindings

The Amlogic SoCs embeds a standalone CEC Controller, this patch adds this
device bindings.

Signed-off-by: Neil Armstrong <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

Documentation/devicetree/bindings/media/meson-ao-cec.txt

···
+* Amlogic Meson AO-CEC driver
+
+The Amlogic Meson AO-CEC module is present is Amlogic SoCs and its purpose is
+to handle communication between HDMI connected devices over the CEC bus.
+
+Required properties:
+  - compatible : value should be following
+	"amlogic,meson-gx-ao-cec"
+
+  - reg : Physical base address of the IP registers and length of memory
+	  mapped region.
+
+  - interrupts : AO-CEC interrupt number to the CPU.
+  - clocks : from common clock binding: handle to AO-CEC clock.
+  - clock-names : from common clock binding: must contain "core",
+		  corresponding to entry in the clocks property.
+  - hdmi-phandle: phandle to the HDMI controller
+
+Example:
+
+cec_AO: cec@100 {
+	compatible = "amlogic,meson-gx-ao-cec";
+	reg = <0x0 0x00100 0x0 0x14>;
+	interrupts = <GIC_SPI 199 IRQ_TYPE_EDGE_RISING>;
+	clocks = <&clkc_AO CLKID_AO_CEC_32K>;
+	clock-names = "core";
+	hdmi-phandle = <&hdmi_tx>;
+};