diff --git a/include/time.h b/include/time.h
index 5952f1b69da..bf5d0c1be7a 100644
--- a/include/time.h
+++ b/include/time.h
@@ -102,7 +102,7 @@
 
 /* Scalar types */
 
-typedef uint32_t  time_t;         /* Holds time in seconds */
+typedef long      time_t;         /* Holds time in seconds */
 typedef uint8_t   clockid_t;      /* Identifies one time base source */
 typedef FAR void *timer_t;        /* Represents one POSIX timer */
 
diff --git a/sched/clock/clock_settime.c b/sched/clock/clock_settime.c
index 6eb8233a8ad..b0f8de9a1b5 100644
--- a/sched/clock/clock_settime.c
+++ b/sched/clock/clock_settime.c
@@ -65,7 +65,8 @@ int clock_settime(clockid_t clock_id, FAR const struct timespec *tp)
    */
 
   if (clock_id == CLOCK_REALTIME &&
-      tp->tv_nsec >= 0 && tp->tv_nsec < 1000000000)
+      tp->tv_nsec >= 0 && tp->tv_nsec < 1000000000 &&
+      tp->tv_sec >= 0)
     {
 #ifndef CONFIG_CLOCK_TIMEKEEPING
       /* Interrupts are disabled here so that the in-memory time