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Commit e42a98b5 authored by Henrik Rydberg's avatar Henrik Rydberg
Browse files

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: default avatarHenrik Rydberg <rydberg@euromail.se>
parent c5f4dec1

Documentation/input/multi-touch-protocol.txt

+8 −1
Original line number Diff line number Diff line
@@ -161,7 +161,8 @@ against the glass. The inner region will increase, and in general, the 
ratio ABS_MT_TOUCH_MAJOR / ABS_MT_WIDTH_MAJOR, which is always smaller than

unity, is related to the contact pressure. For pressure-based devices,

ABS_MT_PRESSURE may be used to provide the pressure on the contact area

instead.

instead. Devices capable of contact hovering can use ABS_MT_DISTANCE to

indicate the distance between the contact and the surface.



In addition to the MAJOR parameters, the oval shape of the contact can be

described by adding the MINOR parameters, such that MAJOR and MINOR are the
@@ -213,6 +214,12 @@ The pressure, in arbitrary units, on the contact area. May be used instead 
of TOUCH and WIDTH for pressure-based devices or any device with a spatial

signal intensity distribution.



ABS_MT_DISTANCE



The distance, in surface units, between the contact and the surface. Zero

distance means the contact is touching the surface. A positive number means

the contact is hovering above the surface.



ABS_MT_ORIENTATION



The orientation of the ellipse. The value should describe a signed quarter

include/linux/input.h

+2 −1
Original line number Diff line number Diff line
@@ -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