media: dt: bindings: Document DT bindings for Analog devices as3645a

Document DT bindings for Analog Devices as3645a flash LED controller which
also supports an indicator LED.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/devicetree/bindings/leds/ams,as3645a.txt

+Analog devices AS3645A device tree bindings
+
+The AS3645A flash LED controller can drive two LEDs, one high current
+flash LED and one indicator LED. The high current flash LED can be
+used in torch mode as well.
+
+Ranges below noted as [a, b] are closed ranges between a and b, i.e. a
+and b are included in the range.
+
+Please also see common.txt in the same directory.
+
+
+Required properties
+===================
+
+compatible	: Must be "ams,as3645a".
+reg		: The I2C address of the device. Typically 0x30.
+
+
+Required properties of the "flash" child node
+=============================================
+
+flash-timeout-us: Flash timeout in microseconds. The value must be in
+		  the range [100000, 850000] and divisible by 50000.
+flash-max-microamp: Maximum flash current in microamperes. Has to be
+		    in the range between [200000, 500000] and
+		    divisible by 20000.
+led-max-microamp: Maximum torch (assist) current in microamperes. The
+		  value must be in the range between [20000, 160000] and
+		  divisible by 20000.
+ams,input-max-microamp: Maximum flash controller input current. The
+			value must be in the range [1250000, 2000000]
+			and divisible by 50000.
+
+
+Optional properties of the "flash" child node
+=============================================
+
+label		: The label of the flash LED.
+
+
+Required properties of the "indicator" child node
+=================================================
+
+led-max-microamp: Maximum indicator current. The allowed values are
+		  2500, 5000, 7500 and 10000.
+
+Optional properties of the "indicator" child node
+=================================================
+
+label		: The label of the indicator LED.
+
+
+Example
+=======
+
+	as3645a@30 {
+		reg = <0x30>;
+		compatible = "ams,as3645a";
+		flash {
+			flash-timeout-us = <150000>;
+			flash-max-microamp = <320000>;
+			led-max-microamp = <60000>;
+			ams,input-max-microamp = <1750000>;
+			label = "as3645a:flash";
+		};
+		indicator {
+			led-max-microamp = <10000>;
+			label = "as3645a:indicator";
+		};
+	};