diff --git a/drivers/timers/arch_alarm.c b/drivers/timers/arch_alarm.c
index f77cec97e63..8c73d5591c7 100644
--- a/drivers/timers/arch_alarm.c
+++ b/drivers/timers/arch_alarm.c
@@ -36,8 +36,8 @@
 #define CONFIG_BOARD_LOOPSPER10USEC  ((CONFIG_BOARD_LOOPSPERMSEC+50)/100)
 #define CONFIG_BOARD_LOOPSPERUSEC    ((CONFIG_BOARD_LOOPSPERMSEC+500)/1000)
 
-#define timespec_to_usec(ts) \
-    ((uint64_t)(ts)->tv_sec * USEC_PER_SEC + (ts)->tv_nsec / NSEC_PER_USEC)
+#define timespec_to_nsec(ts) \
+    ((uint64_t)(ts)->tv_sec * NSEC_PER_SEC + (ts)->tv_nsec)
 
 /****************************************************************************
  * Private Data
@@ -53,12 +53,12 @@ static clock_t g_current_tick;
  * Private Functions
  ****************************************************************************/
 
-static inline void timespec_from_usec(FAR struct timespec *ts,
-                                      uint64_t microseconds)
+static inline void timespec_from_nsec(FAR struct timespec *ts,
+                                      uint64_t nanoseconds)
 {
-  ts->tv_sec    = microseconds / USEC_PER_SEC;
-  microseconds -= (uint64_t)ts->tv_sec * USEC_PER_SEC;
-  ts->tv_nsec   = microseconds * NSEC_PER_USEC;
+  ts->tv_sec    = nanoseconds / NSEC_PER_SEC;
+  nanoseconds -= (uint64_t)ts->tv_sec * NSEC_PER_SEC;
+  ts->tv_nsec   = nanoseconds;
 }
 
 static void udelay_accurate(useconds_t microseconds)
@@ -68,7 +68,7 @@ static void udelay_accurate(useconds_t microseconds)
   struct timespec delta;
 
   ONESHOT_CURRENT(g_oneshot_lower, &now);
-  timespec_from_usec(&delta, microseconds);
+  timespec_from_nsec(&delta, (uint64_t)microseconds * NSEC_PER_USEC);
   clock_timespec_add(&now, &delta, &end);
 
   while (clock_timespec_compare(&now, &end) < 0)
@@ -375,7 +375,7 @@ unsigned long up_perf_gettime(void)
       struct timespec ts;
 
       ONESHOT_CURRENT(g_oneshot_lower, &ts);
-      ret = timespec_to_usec(&ts);
+      ret = timespec_to_nsec(&ts);
     }
 
   return ret;
@@ -383,13 +383,12 @@ unsigned long up_perf_gettime(void)
 
 unsigned long up_perf_getfreq(void)
 {
-  return USEC_PER_SEC;
+  return NSEC_PER_SEC;
 }
 
-void up_perf_convert(unsigned long elapsed,
-                                   FAR struct timespec *ts)
+void up_perf_convert(unsigned long elapsed, FAR struct timespec *ts)
 {
-  timespec_from_usec(ts, elapsed);
+  timespec_from_nsec(ts, elapsed);
 }
 #endif /* CONFIG_ARCH_PERF_EVENTS */