diff options
Diffstat (limited to 'Documentation/input/event-codes.rst')
| -rw-r--r-- | Documentation/input/event-codes.rst | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst index b24b5343f5eb..3118fc1c1e26 100644 --- a/Documentation/input/event-codes.rst +++ b/Documentation/input/event-codes.rst @@ -236,6 +236,21 @@ A few EV_ABS codes have special meanings: - Used to describe multitouch input events. Please see multi-touch-protocol.txt for details. +* ABS_PRESSURE/ABS_MT_PRESSURE: + + - For touch devices, many devices converted contact size into pressure. + A finger flattens with pressure, causing a larger contact area and thus + pressure and contact size are directly related. This is not the case + for other devices, for example digitizers and touchpads with a true + pressure sensor ("pressure pads"). + + A device should set the resolution of the axis to indicate whether the + pressure is in measurable units. If the resolution is zero, the + pressure data is in arbitrary units. If the resolution is nonzero, the + pressure data is in units/gram. For example, a value of 10 with a + resolution of 1 represents 10 gram, a value of 10 with a resolution on + 1000 represents 10 microgram. + EV_SW ----- |