Add support for Apple Magic Trackpad
Apple Magic Trackpad can track individual touch contact but
its driver follows MT-A protocol instead of MT-B protocol.
Specifically, the driver reports event ABS_MT_TRACKING_ID as
the indication of state machine change, instead of reporting
ABS_MT_SLOT event.
This CL makes mtplot work with Apple Magic Trackpad by:
1. Current slot is updated with new ABS_MT_TRACKING_ID.
2. 0 touch major value means current slot (touch contact) is
removed.
3. Use a touch_major value for drawing since the touchpad
does not report pressure value.
BUG=chromium-os:29435
TEST=Connect Stumpy with Apple Magic Trackpad and check that
mtplot works.
Change-Id: Iea827ff36590b7edf9602ca6a3db60c00f0efc66
1 file changed
