backlight: Add GPIO-based backlight driver

The GPIO backlight driver controls the backlight in on/off mode through
a single GPIO.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 92711fe..65698a8 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -32,6 +32,7 @@
 obj-$(CONFIG_BACKLIGHT_DA9052)		+= da9052_bl.o
 obj-$(CONFIG_BACKLIGHT_EP93XX)		+= ep93xx_bl.o
 obj-$(CONFIG_BACKLIGHT_GENERIC)		+= generic_bl.o
+obj-$(CONFIG_BACKLIGHT_GPIO)		+= gpio_backlight.o
 obj-$(CONFIG_BACKLIGHT_HP680)		+= hp680_bl.o
 obj-$(CONFIG_BACKLIGHT_HP700)		+= jornada720_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3533)		+= lm3533_bl.o