media: dt-bindings: media: meson-ao-cec: Add G12A AO-CEC-B Compatible

The Amlogic G12A embeds a second CEC controller named AO-CEC-B, and
the other one is AO-CEC-A described by the current bindings.

The register interface is very close but the internal architecture
is totally different.

The other difference is the clock source, the AO-CEC-B takes the
"oscin", the Always-On Oscillator clock, as input and embeds a
dual-divider clock divider to provide the precise 32768Hz base
clock for CEC communication.
Signed-off-by: Neil Armstrong <narmstrong@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/meson-ao-cec.txt

@@ -4,15 +4,22 @@ 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
+  - compatible : value should be following depending on the SoC :
+	For GXBB, GXL, GXM and G12A (AO_CEC_A module) :
 	"amlogic,meson-gx-ao-cec"
+	For G12A (AO_CEC_B module) :
+	"amlogic,meson-g12a-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",
+  - clock-names : from common clock binding, must contain :
+		For GXBB, GXL, GXM and G12A (AO_CEC_A module) :
+		- "core"
+		For G12A (AO_CEC_B module) :
+		- "oscin"
 		corresponding to entry in the clocks property.
   - hdmi-phandle: phandle to the HDMI controller