diff --git a/tools/testing/selftests/ptp/testptp.c b/tools/testing/selftests/ptp/testptp.c
index c0dd10257df5..49e6eddcb361 100644
--- a/tools/testing/selftests/ptp/testptp.c
+++ b/tools/testing/selftests/ptp/testptp.c
@@ -455,11 +455,11 @@ int main(int argc, char *argv[])
 			interval = t2 - t1;
 			offset = (t2 + t1) / 2 - tp;
 
-			printf("system time: %lld.%u\n",
+			printf("system time: %lld.%09u\n",
 				(pct+2*i)->sec, (pct+2*i)->nsec);
-			printf("phc    time: %lld.%u\n",
+			printf("phc    time: %lld.%09u\n",
 				(pct+2*i+1)->sec, (pct+2*i+1)->nsec);
-			printf("system time: %lld.%u\n",
+			printf("system time: %lld.%09u\n",
 				(pct+2*i+2)->sec, (pct+2*i+2)->nsec);
 			printf("system/phc clock time offset is %" PRId64 " ns\n"
 			       "system     clock time delay  is %" PRId64 " ns\n",