greybus: loopback: add gb_loopback_nsec_to_usec_latency

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>

diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c
index b46ded2..4879edd 100644 (file)
--- a/drivers/staging/greybus/loopback.c
+++ b/drivers/staging/greybus/loopback.c
@@ -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);