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greybus: loopback: add gb_loopback_nsec_to_usec_latency

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A helper function to convert from a nanosecond value to a latency value
expressed in mircoseconds. This will be used again in subsequent patches.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Bryan O'Donoghue 2015-08-17 00:55:05 +01:00 committed by Greg Kroah-Hartman
parent 67d1eeceb1
commit bd416103b2
1 changed files with 10 additions and 3 deletions
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13
drivers/staging/greybus/loopback.c
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@ -283,6 +283,15 @@ static struct attribute *loopback_attrs[] = {
};
ATTRIBUTE_GROUPS(loopback);
static u32 gb_loopback_nsec_to_usec_latency(u64 elapsed_nsecs)
{
u32 lat;
do_div(elapsed_nsecs, NSEC_PER_USEC);
lat = elapsed_nsecs;
return lat;
}
static u64 gb_loopback_calc_latency(struct timeval *ts, struct timeval *te)
{
u64 t1, t2;
@ -532,9 +541,7 @@ static void gb_loopback_calculate_stats(struct gb_loopback *gb)
u64 tmp;
/* Express latency in terms of microseconds */
tmp = gb->elapsed_nsecs;
do_div(tmp, NSEC_PER_USEC);
lat = tmp;
lat = gb_loopback_nsec_to_usec_latency(gb->elapsed_nsecs);
/* Log latency statistic */
gb_loopback_update_stats(&gb_dev.latency, lat);