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 <j.anaszewski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: devicetree@vger.kernel.org
Signed-off-by: Bryan Wu <cooloney@gmail.com>
diff --git a/Documentation/devicetree/bindings/leds/leds-aat1290.txt b/Documentation/devicetree/bindings/leds/leds-aat1290.txt
new file mode 100644
index 0000000..ef88b9c
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-aat1290.txt
@@ -0,0 +1,41 @@
+* 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>;
+ };
+};