leds: Add LED driver for lm3556 chip

LM3556 :
The LM3556 is a 4 MHz fixed-frequency synchronous boost
converter plus 1.5A constant current driver for a high-current white LED.
Datasheet: www.national.com/ds/LM/LM3556.pdf

Tested on OMAP4430

(bryan.wu@canonical.com: use module_i2c_driver() rather than
lm3556_init/lm3556_exit for code simplicity; fixed some typo
pointed out by Rob Landley)

Signed-off-by: G.Shark Jeong <gshark.jeong@gmail.com>
Reviewed-by: Axel Lin <axel.lin@gmail.com>
Reviewed-by: Kim, Milo <Milo.Kim@ti.com>
Acked-by: Rob Landley <rob@landley.net>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 52f1d45..f028f03 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -415,6 +415,14 @@
 	  This option enables support for on-chip LED drivers on
 	  MAXIM MAX8997 PMIC.
 
+config LEDS_LM3556
+	tristate "LED support for LM3556 Chip"
+	depends on LEDS_CLASS && I2C
+	select REGMAP_I2C
+	help
+	  This option enables support for LEDs connected to LM3556.
+	  LM3556 includes Torch, Flash and Indicator functions.
+
 config LEDS_OT200
 	tristate "LED support for the Bachmann OT200"
 	depends on LEDS_CLASS && HAS_IOMEM