Input: fix used slots detection breakage

Commit f8ec894945e7d205ce62be59e55e72c4304e4739 allowed external callers
use slot dropping logic, unfortunately it also broke external users of
input_mt_is_used() as we stopped incrementing frame count unless input
device was set up to automatically drop unused slots.

Fixes: f8ec894945e7d ("Input: MT - make slot cleanup callable outside
mt_sync_frame()")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=83081

Reported-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Input: ALPS - suppress message about 'Unknown touchpad'

When we fail to match data returned by E7 and EC reports we state that we
found "Unknown ALPS touchpad" whereas it is most likely it is not ALPS
touchpad at all. Change wording a bit and reduce the message to debug so
that it does not litter users logs and confuse them.

Reported-by: Paul Menzel <paulepanter@users.sourceforge.net>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Input: elantech - reset the device when elantech probe fails

elantech_init() calls elantech_set_absolute_mode which sets the driver in
an absolute mode. When after this the elantech_init fails, it is best to
turn the ps/2 mouse emulation mode back on by calling psmouse_reset() so
that it can work as a regular mouse.

Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulrik De Bie <ulrik.debie-os@e2big.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Input: elantech - add support for trackpoint found on some v3 models

Some elantech v3 touchpad equipped laptops also have a trackpoint, before
this commit, these give sync errors. With this patch, the trackpoint is
provided as another input device: 'Elantech PS/2 TrackPoint'

The patch will also output messages that do not follow the expected pattern.
In the mean time I've seen 2 unknown packets occasionally:
0x04 , 0x00 , 0x00 , 0x00 , 0x00 , 0x00
0x00 , 0x00 , 0x00 , 0x02 , 0x00 , 0x00
I don't know what those are for, but they can be safely ignored.

Currently all packets that are not known to v3 touchpad and where
packet[3] (the fourth byte) lowest nibble is 6 are now recognized as
PACKET_TRACKPOINT and processed by the new elantech_report_trackpoint.

This has been verified to work on a laptop Lenovo L530 where the
touchpad/trackpoint combined identify themselves as:
psmouse serio1: elantech: assuming hardware version 3 (with firmware version 0x350f02)
psmouse serio1: elantech: Synaptics capabilities query result 0xb9, 0x15, 0x0c.

Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulrik De Bie <ulrik.debie-os@e2big.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>