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, 13 insertions, 0 deletions

diff --git a/drivers/input/input.c b/drivers/input/input.c
index 8ff92aa..e54e002 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -33,6 +33,15 @@ MODULE_LICENSE("GPL");
  * EV_ABS events which should not be cached are listed here.
  */
 static unsigned int input_abs_bypass_init_data[] __initdata = {
+	ABS_MT_TOUCH_MAJOR,
+	ABS_MT_TOUCH_MINOR,
+	ABS_MT_WIDTH_MAJOR,
+	ABS_MT_WIDTH_MINOR,
+	ABS_MT_ORIENTATION,
+	ABS_MT_POSITION_X,
+	ABS_MT_POSITION_Y,
+	ABS_MT_TOOL_TYPE,
+	ABS_MT_BLOB_ID,
 	0
 };
 static unsigned long input_abs_bypass[BITS_TO_LONGS(ABS_CNT)];
@@ -169,6 +178,10 @@ static void input_handle_event(struct input_dev *dev,
 				disposition = INPUT_PASS_TO_HANDLERS;
 			}
 			break;
+		case SYN_MT_REPORT:
+			dev->sync = 0;
+			disposition = INPUT_PASS_TO_HANDLERS;
+			break;
 		}
 		break;