Input: add driver for slidebar on Lenovo IdeaPad laptops

This driver adds support for slidebars found on some Lenovo IdeaPad
laptops (the slidebars work with SlideNav/Desktop Navigator under
Windows).

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=16004

Registers 'IdeaPad Slidebar' input device and
/sys/devices/platform/ideapad_slidebar/slidebar_mode
for switching slidebar's modes.

Now works on:
IdeaPad Y550, Y550P.

May work on (testing and adding new models is needed):
Ideapad Y560, Y460, Y450, Y650,
and, probably, some others.

Signed-off-by: Andrey Moiseev <o2g.org.ru@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 250dc97..bd1c48e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4038,6 +4038,13 @@
 S:	Maintained
 F:	drivers/platform/x86/ideapad-laptop.c
 
+IDEAPAD LAPTOP SLIDEBAR DRIVER
+M:	Andrey Moiseev <o2g.org.ru@gmail.com>
+L:	linux-input@vger.kernel.org
+W:	https://github.com/o2genum/ideapad-slidebar
+S:	Maintained
+F:	drivers/input/misc/ideapad_slidebar.c
+
 IDE/ATAPI DRIVERS
 M:	Borislav Petkov <bp@alien8.de>
 L:	linux-ide@vger.kernel.org