The touchpad on the Acer Aspire One D250 will report out of range values
in the extreme lower portion of the touchpad. These appear as abrupt
changes in the values reported by the hardware from very low values to
very high values, which can cause unexpected vertical jumps in the
position of the mouse pointer.

What seems to be happening is that the value is wrapping to a two's
compliment negative value of higher resolution than the 13-bit value
reported by the hardware, with the high-order bits being truncated. This
patch adds handling for these values by converting them to the
appropriate negative values.

The only tricky part about this is deciding when to treat a number as
negative. It stands to reason that if out of range values can be
reported on the low end then it could also happen on the high end, so
not all out of range values should be treated as negative. The approach
taken here is to split the difference between the maximum legitimate
value for the axis and the maximum possible value that the hardware can
report, treating values greater than this number as negative and all
other values as positive. This can be tweaked later if hardware is found
that operates outside of these parameters.

BugLink: http://bugs.launchpad.net/bugs/1001251
Cc: stable@vger.kernel.org
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Read the Firmware ID and Board Number from a synaptics device at init
and display them in the system log.

Device behavior is very board and firmware dependent.
It may prove useful for users to include this information when providing
bug reports or other feedback.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Move synaptics_invert_y() inside CONFIG_MOUSE_PS2_SYNAPTICS to get rid of
a compile warning when we don't select synaptics support.

drivers/input/mouse/synaptics.c:53:12: warning: ‘synaptics_invert_y’ defined but not used [-Wunused-function]

Signed-off-by: JJ Ding <dgdunix@gmail.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

commit 7968a5dd492ccc38345013e534ad4c8d6eb60ed1
Input: synaptics - add support for Relative mode

Accidentally broke support for advanced gestures (multitouch)
on some trackpads such as the one in my ThinkPad X220 by
incorretly changing the condition for enabling them. This
restores it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: stable@kernel.org [3.3]
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Synaptics touchpads on several Dell laptops, particularly Vostro V13
systems, may not respond properly to PS/2 commands and queries immediately
after resuming from suspend to RAM. This leads to unresponsive touchpad
after suspend/resume cycle.

Adding a 1-second delay after resetting the device allows touchpad to
finish initializing (calibrating?) and start reacting properly.

Reported-by: Daniel Manrique <daniel.manrique@canonical.com>
Tested-by: Daniel Manrique <daniel.manrique@canonical.com>
Cc: stable@kernel.org
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

We have determined that the jumpiness previously seen when using
the synaptics kernel mouse driver on OLPC XO was due to not using
the synaptics X11 userspace driver - the xf86-input-evdev driver was
interpreting 'finger near pad' signals as movements. Newer versions
of xf86-input-evdev fix this issue.

Additionally, the synaptics kernel driver is now usable on this
platform, but only when run in relative mode.

Update the comment and refine the check to allow the synaptics driver
to run on OLPC XO in relative mode.

We will continue investigating the EC issue as time becomes available.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Currently, the synaptics driver puts the device into Absolute mode.
As explained in the synaptics documentation section 3.2, in this mode,
the device sends a continuous stream of packets at the maximum rate
to the host when the user's fingers are near or on the pad or
pressing buttons, and continues streaming for 1 second afterwards.
These packets are even sent when there is no new information to report,
even when they are duplicates of the previous packet.

For embedded systems this is a bit much - it results in a huge
and uninterrupted stream of interrupts at high rate.

This patch adds support for Relative mode, which can be selected as
a new psmouse protocol. In this mode, the device does not send duplicate
packets and acts like a standard PS/2 mouse. However, synaptics-specific
functionality is still available, such as the ability to set the packet
rate, and rather than disabling gestures and taps at the hardware level
unconditionally, a 'synaptics_disable_gesture' sysfs attribute has
been added to allow control of this functionality.

This solves a long standing OLPC issue: synaptics hardware enables
tap to click by default (even in the default relative mode), but we
have found this to be inappropriate for young children and first
time computer users. Enabling the synaptics driver disables tap-to-click,
but we have previously been unable to use this because it also enables
Absolute mode, which is too "spammy" for our desires and actually
overloads our EC with its continuous stream of packets. Now we can enable
the synaptics driver, disabling tap to click while retaining the less
noisy Relative mode.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

This will ensure our reporting is consistent with the rest of the system
and we do not refer to obsolete source file names.

Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: JJ Ding <dgdunix@gmail.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>