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authorBenjamin Tissoires <benjamin.tissoires@gmail.com>2012-11-14 16:59:21 +0100
committerJiri Kosina <jkosina@suse.cz>2012-11-15 10:13:52 +0100
commitaf8036dd749fbf4e732161ff0f3874759b73be40 (patch)
tree67968eee829e6dc6c3020400e7501e60808591f2 /Documentation/input
parent20b60e6dee316cba4092cc7aef391fc6f4491028 (diff)
downloadlinux-af8036dd749fbf4e732161ff0f3874759b73be40.tar.gz
Input: introduce EV_MSC Timestamp
Some devices provides the actual timestamp (hid_dg_scan_time in win8 ones) computed by the hardware itself. This value is global to the frame and is not specific to the multitouch protocol. Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com> Reviewed-by: Henrik Rydberg <rydberg@euromail.se> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'Documentation/input')
-rw-r--r--Documentation/input/event-codes.txt11
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/input/event-codes.txt b/Documentation/input/event-codes.txt
index 53305bd0818..f1ea2c69648 100644
--- a/Documentation/input/event-codes.txt
+++ b/Documentation/input/event-codes.txt
@@ -196,6 +196,17 @@ EV_MSC:
EV_MSC events are used for input and output events that do not fall under other
categories.
+A few EV_MSC codes have special meaning:
+
+* MSC_TIMESTAMP:
+ - Used to report the number of microseconds since the last reset. This event
+ should be coded as an uint32 value, which is allowed to wrap around with
+ no special consequence. It is assumed that the time difference between two
+ consecutive events is reliable on a reasonable time scale (hours).
+ A reset to zero can happen, in which case the time since the last event is
+ unknown. If the device does not provide this information, the driver must
+ not provide it to user space.
+
EV_LED:
----------
EV_LED events are used for input and output to set and query the state of