From: Rodolfo Giometti <giometti@linux.it>

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/pps/Makefile |    2 -
 Documentation/pps/ppsctl.c |   62 +++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)

diff -puN Documentation/pps/Makefile~pps-example-program-to-enable-pps-support-on-serial-ports Documentation/pps/Makefile
--- a/Documentation/pps/Makefile~pps-example-program-to-enable-pps-support-on-serial-ports
+++ a/Documentation/pps/Makefile
@@ -1,4 +1,4 @@
-TARGETS = ppstest
+TARGETS = ppstest ppsctl
 
 CFLAGS += -Wall -O2 -D_GNU_SOURCE
 CFLAGS += -I .
diff -puN /dev/null Documentation/pps/ppsctl.c
--- /dev/null
+++ a/Documentation/pps/ppsctl.c
@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <linux/serial.h>
+
+void usage(char *name)
+{
+	fprintf(stderr, "usage: %s <ttyS> [enable|disable]\n", name);
+
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[])
+{
+	int fd;
+	int ret;
+	struct serial_struct ss;
+
+	if (argc < 2)
+		usage(argv[0]);
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		perror("open");
+		exit(EXIT_FAILURE);
+	}
+
+	ret = ioctl(fd, TIOCGSERIAL, &ss);
+	if (ret < 0) {
+		perror("ioctl(TIOCGSERIAL)");
+		exit(EXIT_FAILURE);
+	}
+
+	if (argc < 3) {		/* just read PPS status */
+		printf("PPS is %sabled\n",
+		       ss.flags & ASYNC_HARDPPS_CD ? "en" : "dis");
+		exit(EXIT_SUCCESS);
+	}
+
+	if (argv[2][0] == 'e' || argv[2][0] == '1')
+		ss.flags |= ASYNC_HARDPPS_CD;
+	else if (argv[2][0] == 'd' || argv[2][0] == '0')
+		ss.flags &= ~ASYNC_HARDPPS_CD;
+	else {
+		fprintf(stderr, "invalid state argument \"%s\"\n", argv[2]);
+		exit(EXIT_FAILURE);
+	}
+
+	ret = ioctl(fd, TIOCSSERIAL, &ss);
+	if (ret < 0) {
+		perror("ioctl(TIOCSSERIAL)");
+		exit(EXIT_FAILURE);
+	}
+
+	return 0;
+}
_