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Input: allow drivers specify timestamp for input events

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Currently, evdev stamps events with timestamps acquired in evdev_events()
However, this timestamping may not be accurate in terms of measuring
when the actual event happened.

Let's allow individual drivers specify timestamp in order to provide a more
accurate sense of time for the event. It is expected that drivers will set the
timestamp in their hard interrupt routine.

Signed-off-by: Atif Niyaz <atifniyaz@google.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Atif Niyaz
2019-07-24 22:26:31 +03:00
committed by Dmitry Torokhov
parent c2433827c1
commit 3b51c44bd6
3 changed files with 62 additions and 27 deletions
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40
drivers/input/input.c
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@@ -1894,6 +1894,46 @@ void input_free_device(struct input_dev *dev)
}
EXPORT_SYMBOL(input_free_device);
/**
* input_set_timestamp - set timestamp for input events
* @dev: input device to set timestamp for
* @timestamp: the time at which the event has occurred
* in CLOCK_MONOTONIC
*
* This function is intended to provide to the input system a more
* accurate time of when an event actually occurred. The driver should
* call this function as soon as a timestamp is acquired ensuring
* clock conversions in input_set_timestamp are done correctly.
*
* The system entering suspend state between timestamp acquisition and
* calling input_set_timestamp can result in inaccurate conversions.
*/
void input_set_timestamp(struct input_dev *dev, ktime_t timestamp)
{
dev->timestamp[INPUT_CLK_MONO] = timestamp;
dev->timestamp[INPUT_CLK_REAL] = ktime_mono_to_real(timestamp);
dev->timestamp[INPUT_CLK_BOOT] = ktime_mono_to_any(timestamp,
TK_OFFS_BOOT);
}
EXPORT_SYMBOL(input_set_timestamp);
/**
* input_get_timestamp - get timestamp for input events
* @dev: input device to get timestamp from
*
* A valid timestamp is a timestamp of non-zero value.
*/
ktime_t *input_get_timestamp(struct input_dev *dev)
{
const ktime_t invalid_timestamp = ktime_set(0, 0);
if (!ktime_compare(dev->timestamp[INPUT_CLK_MONO], invalid_timestamp))
input_set_timestamp(dev, ktime_get());
return dev->timestamp;
}
EXPORT_SYMBOL(input_get_timestamp);
/**
* input_set_capability - mark device as capable of a certain event
* @dev: device that is capable of emitting or accepting event