* Skyworks Solutions, Inc. AAT1290 Current Regulator for Flash LEDs

The device is controlled through two pins: FL_EN and EN_SET. The pins when,
asserted high, enable flash strobe and movie mode (max 1/2 of flash current)
respectively.

Required properties:

- compatible : Must be "skyworks,aat1290".
- flen-gpios : Must be device tree identifier of the flash device FL_EN pin.
- enset-gpios : Must be device tree identifier of the flash device EN_SET pin.

A discrete LED element connected to the device must be represented by a child
node - see Documentation/devicetree/bindings/leds/common.txt.

Required properties of the LED child node:
- led-max-microamp : see Documentation/devicetree/bindings/leds/common.txt
- flash-max-microamp : see Documentation/devicetree/bindings/leds/common.txt
                       Maximum flash LED supply current can be calculated using
                       following formula: I = 1A * 162kohm / Rset.
- flash-timeout-us : see Documentation/devicetree/bindings/leds/common.txt
                     Maximum flash timeout can be calculated using following
                     formula: T = 8.82 * 10^9 * Ct.

Optional properties of the LED child node:
- label : see Documentation/devicetree/bindings/leds/common.txt

Example (by Ct = 220nF, Rset = 160kohm):

aat1290 {
	compatible = "skyworks,aat1290";
	flen-gpios = <&gpj1 1 GPIO_ACTIVE_HIGH>;
	enset-gpios = <&gpj1 2 GPIO_ACTIVE_HIGH>;

	camera_flash: flash-led {
		label = "aat1290-flash";
		led-max-microamp = <520833>;
		flash-max-microamp = <1012500>;
		flash-timeout-us = <1940000>;
	};
};

Add documentation for the Skyworks AAT1290
DT: Add documentation for the Skyworks AAT1290

This patch adds device tree binding documentation for
1.5A Step-Up Current Regulator for Flash LEDs.

Signed-off-by: Jacek Anaszewski <6a953cb1c532e2765a42e582ecefff5a01106214@samsung.com>
Acked-by: Kyungmin Park <504c23c4986a3760712724894be3105092c27331@samsung.com>
Acked-by: Sakari Ailus <8d98c2be02a446df653daa2c00496b87f3f016e4@linux.intel.com>
Cc: Richard Purdie <a03894c799ea916bd571ce8f12ed88f6fb3400f7@rpsys.net>
Cc: eb682e570f95b554c8a7dc560ee59b91b930a718@vger.kernel.org
Signed-off-by: Bryan Wu <956b36c0f472d2edb239225c10f7e4411d1efbb9@gmail.com>
