diff options
authorHenrik Rydberg <rydberg@euromail.se>2010-12-06 10:05:43 +0100
committerHenrik Rydberg <rydberg@euromail.se>2010-12-16 10:42:29 +0100
commite42a98b520bb22535687ead3120e80edc268279a (patch)
parentc5f4dec1ceb6ab773bbbefbe64a7c990c7d6b17f (diff)
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>
2 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/input/multi-touch-protocol.txt b/Documentation/input/multi-touch-protocol.txt
index bdcba154b83..07215fa0c58 100644
--- a/Documentation/input/multi-touch-protocol.txt
+++ b/Documentation/input/multi-touch-protocol.txt
@@ -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. 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.
+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.
The orientation of the ellipse. The value should describe a signed quarter
diff --git a/include/linux/input.h b/include/linux/input.h
index 6de145df4c1..b3a1e02080c 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_MAX 0x3f