input: mt: Add hovering distance axis

Touch devices capable of hovering, i.e., fingers detected a
distance from the surface, are not supported by the current
input MT protocol. This patch adds ABS_MT_DISTANCE, which may
be used to indicate the distance between the contact and the
surface.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/input.h b/include/linux/input.h
index 6de145df4c1c..b3a1e02080c0 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -733,11 +733,12 @@ struct input_keymap_entry {
 #define ABS_MT_BLOB_ID          0x38    /* Group a set of packets as a blob */
 #define ABS_MT_TRACKING_ID      0x39    /* Unique ID of initiated contact */
 #define ABS_MT_PRESSURE         0x3a    /* Pressure on contact area */
+#define ABS_MT_DISTANCE         0x3b    /* Contact hover distance */
 
 #ifdef __KERNEL__
 /* Implementation details, userspace should not care about these */
 #define ABS_MT_FIRST            ABS_MT_TOUCH_MAJOR
-#define ABS_MT_LAST             ABS_MT_PRESSURE
+#define ABS_MT_LAST             ABS_MT_DISTANCE
 #endif
 
 #define ABS_MAX                 0x3f