Input: psmouse - add OLPC touchpad driver

This adds support for OLPC's touchpad.  It has lots of neat features,
none of which are enabled because the hardware is too buggy.  Instead,
we use it like a normal touchpad, but with a number of workarounds in
place to deal with the frequent hardware spasms.  Humidity changes,
sweat, tinfoil underwear, plugging in AC, drinks, evil felines.. All
tend to cause the touchpad to freak out.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/mouse/Kconfig

@@ -96,6 +96,16 @@ config MOUSE_PS2_TOUCHKIT
 
 	  If unsure, say N.
 
+config MOUSE_PS2_OLPC
+	bool "OLPC PS/2 mouse protocol extension"
+	depends on MOUSE_PS2 && OLPC
+	help
+	  Say Y here if you have an OLPC XO-1 laptop (with built-in
+	  PS/2 touchpad/tablet device).  The manufacturer calls the
+	  touchpad an HGPK.
+
+	  If unsure, say N.
+
 config MOUSE_SERIAL
 	tristate "Serial mouse"
 	select SERIO

drivers/input/mouse/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_MOUSE_GPIO)	+= gpio_mouse.o
 psmouse-objs := psmouse-base.o synaptics.o
 
 psmouse-$(CONFIG_MOUSE_PS2_ALPS)	+= alps.o
+psmouse-$(CONFIG_MOUSE_PS2_OLPC)	+= hgpk.o
 psmouse-$(CONFIG_MOUSE_PS2_LOGIPS2PP)	+= logips2pp.o
 psmouse-$(CONFIG_MOUSE_PS2_LIFEBOOK)	+= lifebook.o
 psmouse-$(CONFIG_MOUSE_PS2_TRACKPOINT)	+= trackpoint.o