diff --git a/tools/testing/selftests/timers/Makefile b/tools/testing/selftests/timers/Makefile
index d0bfb2d..01b5a2e 100644
--- a/tools/testing/selftests/timers/Makefile
+++ b/tools/testing/selftests/timers/Makefile
@@ -3,10 +3,12 @@ BUILD_FLAGS = -DKTEST
 CFLAGS += -O3 -Wl,-no-as-needed -Wall $(BUILD_FLAGS)
 LDFLAGS += -lrt -lpthread
 bins = posix_timers nanosleep inconsistency-check nsleep-lat raw_skew \
-	set-timer-lat threadtest mqueue-lat
+	set-timer-lat threadtest mqueue-lat valid-adjtimex
 
 all: ${bins}
 
+# these are all "safe" tests that don't modify
+# system time or require escalated privledges
 run_tests: all
 	./posix_timers
 	./nanosleep
@@ -16,5 +18,12 @@ run_tests: all
 	./inconsistency-check
 	./raw_skew
 	./threadtest -t 30 -n 8
+
+# these tests require escalated privledges
+# and may modify the system time or trigger
+# other behavior like suspend
+run_destructive_tests: all
+	./valid-adjtimex
+
 clean:
 	rm -f ${bins}
diff --git a/tools/testing/selftests/timers/valid-adjtimex.c b/tools/testing/selftests/timers/valid-adjtimex.c
new file mode 100644
index 0000000..e86d937
--- /dev/null
+++ b/tools/testing/selftests/timers/valid-adjtimex.c
@@ -0,0 +1,202 @@
+/* valid adjtimex test
+ *              by: John Stultz <john.stultz@linaro.org>
+ *              (C) Copyright Linaro 2015
+ *              Licensed under the GPLv2
+ *
+ *  This test validates adjtimex interface with valid
+ *  and invalid test data.
+ *
+ *  Usage: valid-adjtimex
+ *
+ *  To build:
+ *	$ gcc valid-adjtimex.c -o valid-adjtimex -lrt
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/time.h>
+#include <sys/timex.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#ifdef KTEST
+#include "../kselftest.h"
+#else
+static inline int ksft_exit_pass(void)
+{
+	exit(0);
+}
+static inline int ksft_exit_fail(void)
+{
+	exit(1);
+}
+#endif
+
+#define NSEC_PER_SEC 1000000000L
+
+/* clear NTP time_status & time_state */
+int clear_time_state(void)
+{
+	struct timex tx;
+	int ret;
+
+	tx.modes = ADJ_STATUS;
+	tx.status = 0;
+	ret = adjtimex(&tx);
+	return ret;
+}
+
+#define NUM_FREQ_VALID 32
+#define NUM_FREQ_OUTOFRANGE 4
+#define NUM_FREQ_INVALID 2
+
+long valid_freq[NUM_FREQ_VALID] = {
+	-499<<16,
+	-450<<16,
+	-400<<16,
+	-350<<16,
+	-300<<16,
+	-250<<16,
+	-200<<16,
+	-150<<16,
+	-100<<16,
+	-75<<16,
+	-50<<16,
+	-25<<16,
+	-10<<16,
+	-5<<16,
+	-1<<16,
+	-1000,
+	1<<16,
+	5<<16,
+	10<<16,
+	25<<16,
+	50<<16,
+	75<<16,
+	100<<16,
+	150<<16,
+	200<<16,
+	250<<16,
+	300<<16,
+	350<<16,
+	400<<16,
+	450<<16,
+	499<<16,
+};
+
+long outofrange_freq[NUM_FREQ_OUTOFRANGE] = {
+	-1000<<16,
+	-550<<16,
+	550<<16,
+	1000<<16,
+};
+
+#define LONG_MAX (~0UL>>1)
+#define LONG_MIN (-LONG_MAX - 1)
+
+long invalid_freq[NUM_FREQ_INVALID] = {
+	LONG_MAX,
+	LONG_MIN,
+};
+
+int validate_freq(void)
+{
+	struct timex tx;
+	int ret, pass = 0;
+	int i;
+
+	clear_time_state();
+
+	memset(&tx, 0, sizeof(struct timex));
+	/* Set the leap second insert flag */
+
+	printf("Testing ADJ_FREQ... ");
+	for (i = 0; i < NUM_FREQ_VALID; i++) {
+		tx.modes = ADJ_FREQUENCY;
+		tx.freq = valid_freq[i];
+
+		ret = adjtimex(&tx);
+		if (ret < 0) {
+			printf("[FAIL]\n");
+			printf("Error: adjtimex(ADJ_FREQ, %ld - %ld ppm\n",
+				valid_freq[i], valid_freq[i]>>16);
+			pass = -1;
+			goto out;
+		}
+		tx.modes = 0;
+		ret = adjtimex(&tx);
+		if (tx.freq != valid_freq[i]) {
+			printf("Warning: freq value %ld not what we set it (%ld)!\n",
+					tx.freq, valid_freq[i]);
+		}
+	}
+	for (i = 0; i < NUM_FREQ_OUTOFRANGE; i++) {
+		tx.modes = ADJ_FREQUENCY;
+		tx.freq = outofrange_freq[i];
+
+		ret = adjtimex(&tx);
+		if (ret < 0) {
+			printf("[FAIL]\n");
+			printf("Error: adjtimex(ADJ_FREQ, %ld - %ld ppm\n",
+				outofrange_freq[i], outofrange_freq[i]>>16);
+			pass = -1;
+			goto out;
+		}
+		tx.modes = 0;
+		ret = adjtimex(&tx);
+		if (tx.freq == outofrange_freq[i]) {
+			printf("[FAIL]\n");
+			printf("ERROR: out of range value %ld actually set!\n",
+					tx.freq);
+			pass = -1;
+			goto out;
+		}
+	}
+
+
+	if (sizeof(long) == 8) { /* this case only applies to 64bit systems */
+		for (i = 0; i < NUM_FREQ_INVALID; i++) {
+			tx.modes = ADJ_FREQUENCY;
+			tx.freq = invalid_freq[i];
+			ret = adjtimex(&tx);
+			if (ret >= 0) {
+				printf("[FAIL]\n");
+				printf("Error: No failure on invalid ADJ_FREQUENCY %ld\n",
+					invalid_freq[i]);
+				pass = -1;
+				goto out;
+			}
+		}
+	}
+
+	printf("[OK]\n");
+out:
+	/* reset freq to zero */
+	tx.modes = ADJ_FREQUENCY;
+	tx.freq = 0;
+	ret = adjtimex(&tx);
+
+	return pass;
+}
+
+
+int main(int argc, char **argv)
+{
+	if (validate_freq())
+		return ksft_exit_fail();
+
+	return ksft_exit_pass();
+}
