leds: introduce lp5521 led driver

LP5521 is a three channel led driver with support
for hardware accelerated patterns (currently used
via lp5521-only sysfs interface).

Currently, it's used on n810 device.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

drivers/leds/Kconfig

@@ -145,6 +145,16 @@ config LEDS_GPIO_OF
 	  of_platform devices.  For instance, LEDs which are listed in a "dts"
 	  file.
 
+config LEDS_LP5521
+	tristate "LED Support for the LP5521 LEDs"
+	depends on LEDS_CLASS && I2C
+	help
+	  If you say 'Y' here you get support for the National Semiconductor
+	  LP5521 LED driver used in n8x0 boards.
+
+	  This driver can be built as a module by choosing 'M'. The module
+	  will be called leds-lp5521.
+
 config LEDS_CLEVO_MAIL
 	tristate "Mail LED on Clevo notebook"
 	depends on LEDS_CLASS && X86 && SERIO_I8042 && DMI