From df391e0eda1e678add56a8e34226edf05d89af6a Mon Sep 17 00:00:00 2001
From: Henrik Rydberg <rydberg@euromail.se>
Date: Sat, 23 May 2009 09:51:20 -0700
Subject: Input: multitouch - add tracking ID to the protocol
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

There are a few multi-touch devices that support finger tracking
well in hardware, Stantum being the prime example. By exposing the
tracking ID in the MT protocol, evdev bandwidth and cpu usage in
user space can be reduced.

This patch adds the ABS_MT_TRACKING_ID to the MT protocol.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Tested-by: Stéphane Chatty <chatty@enac.fr>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
 drivers/input/input.c | 1 +
 include/linux/input.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/input/input.c b/drivers/input/input.c
index e54e002665b..5d445f48789 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -42,6 +42,7 @@ static unsigned int input_abs_bypass_init_data[] __initdata = {
 	ABS_MT_POSITION_Y,
 	ABS_MT_TOOL_TYPE,
 	ABS_MT_BLOB_ID,
+	ABS_MT_TRACKING_ID,
 	0
 };
 static unsigned long input_abs_bypass[BITS_TO_LONGS(ABS_CNT)];
diff --git a/include/linux/input.h b/include/linux/input.h
index 0e6ff5de358..6fed4f6a9c9 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -656,6 +656,7 @@ struct input_absinfo {
 #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_MT_TRACKING_ID	0x39	/* Unique ID of initiated contact */
 
 #define ABS_MAX			0x3f
 #define ABS_CNT			(ABS_MAX+1)
-- 
cgit v1.2.3-70-g09d2