Input: generic driver for rotary encoders on GPIOs

This patch adds a generic driver for rotary encoders connected to GPIO
pins of a system. It relies on gpiolib and generic hardware irqs. The
documentation that also comes with this patch explains the concept and
how to use the driver.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index bb62e6e..e86cee6 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -22,3 +22,5 @@
 obj-$(CONFIG_INPUT_APANEL)		+= apanel.o
 obj-$(CONFIG_INPUT_SGI_BTNS)		+= sgi_btns.o
 obj-$(CONFIG_INPUT_PCF50633_PMU)	+= pcf50633-input.o
+obj-$(CONFIG_INPUT_GPIO_ROTARY_ENCODER)	+= rotary_encoder.o
+