testptp: Add support for testing ptp_clock_info .adjphase callback

Invoke clock_adjtime syscall with tx.modes set with ADJ_OFFSET when testptp
is invoked with a phase adjustment offset value. Support seconds and
nanoseconds for the offset value.

Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Maciek Machnikowski <maciek@machnikowski.net>
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/ptp/testptp.c

@@ -134,6 +134,7 @@ static void usage(char *progname)
 		"            1 - external time stamp\n"
 		"            2 - periodic output\n"
 		" -n val     shift the ptp clock time by 'val' nanoseconds\n"
+		" -o val     phase offset (in nanoseconds) to be provided to the PHC servo\n"
 		" -p val     enable output with a period of 'val' nanoseconds\n"
 		" -H val     set output phase to 'val' nanoseconds (requires -p)\n"
 		" -w val     set output pulse width to 'val' nanoseconds (requires -p)\n"
@@ -167,6 +168,7 @@ int main(int argc, char *argv[])
 	int adjfreq = 0x7fffffff;
 	int adjtime = 0;
 	int adjns = 0;
+	int adjphase = 0;
 	int capabilities = 0;
 	int extts = 0;
 	int flagtest = 0;
@@ -188,7 +190,7 @@ int main(int argc, char *argv[])
 
 	progname = strrchr(argv[0], '/');
 	progname = progname ? 1+progname : argv[0];
-	while (EOF != (c = getopt(argc, argv, "cd:e:f:ghH:i:k:lL:n:p:P:sSt:T:w:z"))) {
+	while (EOF != (c = getopt(argc, argv, "cd:e:f:ghH:i:k:lL:n:o:p:P:sSt:T:w:z"))) {
 		switch (c) {
 		case 'c':
 			capabilities = 1;
@@ -228,6 +230,9 @@ int main(int argc, char *argv[])
 		case 'n':
 			adjns = atoi(optarg);
 			break;
+		case 'o':
+			adjphase = atoi(optarg);
+			break;
 		case 'p':
 			perout = atoll(optarg);
 			break;
@@ -327,6 +332,18 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	if (adjphase) {
+		memset(&tx, 0, sizeof(tx));
+		tx.modes = ADJ_OFFSET | ADJ_NANO;
+		tx.offset = adjphase;
+
+		if (clock_adjtime(clkid, &tx) < 0) {
+			perror("clock_adjtime");
+		} else {
+			puts("phase adjustment okay");
+		}
+	}
+
 	if (gettime) {
 		if (clock_gettime(clkid, &ts)) {
 			perror("clock_gettime");