Fixes the following sparse warning:
drivers/input/input-mt.c:138:40: warning: Using plain integer as NULL pointer
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NHenrik Rydberg <rydberg@euromail.se>

These files are not modules but are exporting symbols and/or
making use of THIS_MODULE macro.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

"4-finger scroll" is a gesture supported by some applications and
operating systems.

"Resting thumb" is when a clickpad user rests a finger (e.g., a
thumb), in a "click zone" (typically the bottom of the touchpad) in
anticipation of click+move=select gestures.

Thus, "4-finger scroll + resting thumb" is a 5-finger gesture.
To allow userspace to detect this gesture, we send BTN_TOOL_QUINTTAP.
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Acked-by: NChase Douglas <chase.douglas@canonical.com>
Acked-by: NHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

The drivers using the type B protocol all report tracking information
the same way. The contact id is semantically equivalent to
ABS_MT_SLOT, and the handling of ABS_MT_TRACKING_ID only complicates
the driver. The situation can be improved upon by providing a common
pointer emulation code, thereby removing the need for the tracking id
in the driver.  This patch moves all tracking event handling over to
the input core, simplifying both the existing drivers and the ones
currently in preparation.
Acked-by: NPing Cheng <pingc@wacom.com>
Acked-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NHenrik Rydberg <rydberg@euromail.se>

The MT slots devices all follow the same initialization pattern
of creating slots and hinting about buffer size. Let drivers call
an initialization function instead, and make sure it can be called
repeatedly without side effects.
Signed-off-by: NHenrik Rydberg <rydberg@euromail.se>

In preparation for common code to handle a larger set of MT slots
devices, move the slots handling over to a separate file.
Signed-off-by: NHenrik Rydberg <rydberg@euromail.se>