Input: add detailed multi-touch finger data report protocol

In order to utilize the full power of the new multi-touch devices, a
way to report detailed finger data to user space is needed. This patch
adds a multi-touch (MT) protocol which allows drivers to report details
for an arbitrary number of fingers.

The driver sends a SYN_MT_REPORT event via the input_mt_sync() function
when a complete finger has been reported.

In order to stay compatible with existing applications, the data
reported in a finger packet must not be recognized as single-touch
events. In addition, all finger data must bypass input filtering,
since subsequent events of the same type refer to different fingers.

A set of ABS_MT events with the desired properties are defined. The
events are divided into categories, to allow for partial implementation.
The minimum set consists of ABS_MT_TOUCH_MAJOR, ABS_MT_POSITION_X and
ABS_MT_POSITION_Y, which allows for multiple fingers to be tracked.
If the device supports it, the ABS_MT_WIDTH_MAJOR may be used to provide
the size of the approaching finger. Anisotropy and direction may be
specified with ABS_MT_TOUCH_MINOR, ABS_MT_WIDTH_MINOR and
ABS_MT_ORIENTATION. Devices with more granular information may specify
general shapes as blobs, i.e., as a sequence of rectangular shapes
grouped together by a ABS_MT_BLOB_ID. Finally, the ABS_MT_TOOL_TYPE
may be used to specify whether the touching tool is a finger or a pen.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/input.h b/include/linux/input.h
index 32cb825939be..0e6ff5de3588 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -106,6 +106,7 @@ struct input_absinfo {
 
 #define SYN_REPORT              0
 #define SYN_CONFIG              1
+#define SYN_MT_REPORT           2
 
 /*
  * Keys and buttons
@@ -645,6 +646,17 @@ struct input_absinfo {
 #define ABS_TOOL_WIDTH          0x1c
 #define ABS_VOLUME              0x20
 #define ABS_MISC                0x28
+
+#define ABS_MT_TOUCH_MAJOR      0x30    /* Major axis of touching ellipse */
+#define ABS_MT_TOUCH_MINOR      0x31    /* Minor axis (omit if circular) */
+#define ABS_MT_WIDTH_MAJOR      0x32    /* Major axis of approaching ellipse */
+#define ABS_MT_WIDTH_MINOR      0x33    /* Minor axis (omit if circular) */
+#define ABS_MT_ORIENTATION      0x34    /* Ellipse orientation */
+#define ABS_MT_POSITION_X       0x35    /* Center X ellipse position */
+#define ABS_MT_POSITION_Y       0x36    /* Center Y ellipse position */
+#define ABS_MT_TOOL_TYPE        0x37    /* Type of touching device */
+#define ABS_MT_BLOB_ID          0x38    /* Group a set of packets as a blob */
+
 #define ABS_MAX                 0x3f
 #define ABS_CNT                 (ABS_MAX+1)
 
@@ -744,6 +756,12 @@ struct input_absinfo {
 #define BUS_ATARI               0x1B
 
 /*
+ * MT_TOOL types
+ */
+#define MT_TOOL_FINGER          0
+#define MT_TOOL_PEN             1
+
+/*
  * Values describing the status of a force-feedback effect
  */
 #define FF_STATUS_STOPPED       0x00
@@ -1312,6 +1330,11 @@ static inline void input_sync(struct input_dev *dev)
         input_event(dev, EV_SYN, SYN_REPORT, 0);
 }
 
+static inline void input_mt_sync(struct input_dev *dev)
+{
+        input_event(dev, EV_SYN, SYN_MT_REPORT, 0);
+}
+
 void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code);
 
 static inline void input_set_abs_params(struct input_dev *dev, int axis, int min, int max, int fuzz, int flat)