diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index bf6468c56419..c86a31395cdf 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -108,16 +108,20 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
 {
 	struct ptp_clock *ptp =
 		container_of(pccontext->clk, struct ptp_clock, clock);
+	struct ptp_private_ctxdata *ctxdata;
 	struct timestamp_event_queue *queue;
 	char debugfsname[32];
 	unsigned long flags;
 
-	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
-	if (!queue)
+	ctxdata = kzalloc(sizeof(*ctxdata), GFP_KERNEL);
+	if (!ctxdata)
 		return -EINVAL;
+	ctxdata->fmode = fmode;
+
+	queue = &ctxdata->queue;
 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
 	if (!queue->mask) {
-		kfree(queue);
+		kfree(ctxdata);
 		return -EINVAL;
 	}
 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
@@ -125,7 +129,7 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
 	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
 	list_add_tail(&queue->qlist, &ptp->tsevqs);
 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
-	pccontext->private_clkdata = queue;
+	pccontext->private_clkdata = ctxdata;
 
 	/* Debugfs contents */
 	sprintf(debugfsname, "0x%p", queue);
@@ -142,7 +146,8 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
 
 int ptp_release(struct posix_clock_context *pccontext)
 {
-	struct timestamp_event_queue *queue = pccontext->private_clkdata;
+	struct ptp_private_ctxdata *ctxdata = pccontext->private_clkdata;
+	struct timestamp_event_queue *queue = &ctxdata->queue;
 	unsigned long flags;
 	struct ptp_clock *ptp =
 		container_of(pccontext->clk, struct ptp_clock, clock);
@@ -153,7 +158,7 @@ int ptp_release(struct posix_clock_context *pccontext)
 	list_del(&queue->qlist);
 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
 	bitmap_free(queue->mask);
-	kfree(queue);
+	kfree(ctxdata);
 	return 0;
 }
 
@@ -167,6 +172,7 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
 	struct system_device_crosststamp xtstamp;
 	struct ptp_clock_info *ops = ptp->info;
 	struct ptp_sys_offset *sysoff = NULL;
+	struct ptp_private_ctxdata *ctxdata;
 	struct timestamp_event_queue *tsevq;
 	struct ptp_system_timestamp sts;
 	struct ptp_clock_request req;
@@ -180,7 +186,8 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
 	if (in_compat_syscall() && cmd != PTP_ENABLE_PPS && cmd != PTP_ENABLE_PPS2)
 		arg = (unsigned long)compat_ptr(arg);
 
-	tsevq = pccontext->private_clkdata;
+	ctxdata = pccontext->private_clkdata;
+	tsevq = &ctxdata->queue;
 
 	switch (cmd) {
 
@@ -205,6 +212,11 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
 
 	case PTP_EXTTS_REQUEST:
 	case PTP_EXTTS_REQUEST2:
+		if ((ctxdata->fmode & FMODE_WRITE) == 0) {
+			err = -EACCES;
+			break;
+		}
+
 		memset(&req, 0, sizeof(req));
 
 		if (copy_from_user(&req.extts, (void __user *)arg,
@@ -246,6 +258,10 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
 
 	case PTP_PEROUT_REQUEST:
 	case PTP_PEROUT_REQUEST2:
+		if ((ctxdata->fmode & FMODE_WRITE) == 0) {
+			err = -EACCES;
+			break;
+		}
 		memset(&req, 0, sizeof(req));
 
 		if (copy_from_user(&req.perout, (void __user *)arg,
@@ -314,6 +330,10 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
 
 	case PTP_ENABLE_PPS:
 	case PTP_ENABLE_PPS2:
+		if ((ctxdata->fmode & FMODE_WRITE) == 0) {
+			err = -EACCES;
+			break;
+		}
 		memset(&req, 0, sizeof(req));
 
 		if (!capable(CAP_SYS_TIME))
@@ -456,6 +476,10 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
 
 	case PTP_PIN_SETFUNC:
 	case PTP_PIN_SETFUNC2:
+		if ((ctxdata->fmode & FMODE_WRITE) == 0) {
+			err = -EACCES;
+			break;
+		}
 		if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
 			err = -EFAULT;
 			break;
@@ -516,15 +540,15 @@ __poll_t ptp_poll(struct posix_clock_context *pccontext, struct file *fp,
 {
 	struct ptp_clock *ptp =
 		container_of(pccontext->clk, struct ptp_clock, clock);
-	struct timestamp_event_queue *queue;
+	struct ptp_private_ctxdata *ctxdata;
 
-	queue = pccontext->private_clkdata;
-	if (!queue)
+	ctxdata = pccontext->private_clkdata;
+	if (!ctxdata)
 		return EPOLLERR;
 
 	poll_wait(fp, &ptp->tsev_wq, wait);
 
-	return queue_cnt(queue) ? EPOLLIN : 0;
+	return queue_cnt(&ctxdata->queue) ? EPOLLIN : 0;
 }
 
 #define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))
@@ -534,17 +558,19 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags,
 {
 	struct ptp_clock *ptp =
 		container_of(pccontext->clk, struct ptp_clock, clock);
+	struct ptp_private_ctxdata *ctxdata;
 	struct timestamp_event_queue *queue;
 	struct ptp_extts_event *event;
 	unsigned long flags;
 	size_t qcnt, i;
 	int result;
 
-	queue = pccontext->private_clkdata;
-	if (!queue) {
+	ctxdata = pccontext->private_clkdata;
+	if (!ctxdata) {
 		result = -EINVAL;
 		goto exit;
 	}
+	queue = &ctxdata->queue;
 
 	if (cnt % sizeof(struct ptp_extts_event) != 0) {
 		result = -EINVAL;
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index 18934e28469e..b14e7d26a11c 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -35,6 +35,11 @@ struct timestamp_event_queue {
 	struct debugfs_u32_array dfs_bitmap;
 };
 
+struct ptp_private_ctxdata {
+	struct timestamp_event_queue queue;
+	fmode_t fmode;
+};
+
 struct ptp_clock {
 	struct posix_clock clock;
 	struct device dev;
diff --git a/tools/testing/selftests/ptp/testptp.c b/tools/testing/selftests/ptp/testptp.c
index 58064151f2c8..edc08a4433fd 100644
--- a/tools/testing/selftests/ptp/testptp.c
+++ b/tools/testing/selftests/ptp/testptp.c
@@ -140,6 +140,7 @@ static void usage(char *progname)
 		" -H val     set output phase to 'val' nanoseconds (requires -p)\n"
 		" -w val     set output pulse width to 'val' nanoseconds (requires -p)\n"
 		" -P val     enable or disable (val=1|0) the system clock PPS\n"
+		" -r         open the ptp clock in readonly mode\n"
 		" -s         set the ptp clock time from the system time\n"
 		" -S         set the system time from the ptp clock time\n"
 		" -t val     shift the ptp clock time by 'val' seconds\n"
@@ -188,6 +189,7 @@ int main(int argc, char *argv[])
 	int pin_index = -1, pin_func;
 	int pps = -1;
 	int seconds = 0;
+	int readonly = 0;
 	int settime = 0;
 	int channel = -1;
 	clockid_t ext_clockid = CLOCK_REALTIME;
@@ -200,7 +202,7 @@ 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:F:ghH:i:k:lL:n:o:p:P:sSt:T:w:x:Xy:z"))) {
+	while (EOF != (c = getopt(argc, argv, "cd:e:f:F:ghH:i:k:lL:n:o:p:P:rsSt:T:w:x:Xy:z"))) {
 		switch (c) {
 		case 'c':
 			capabilities = 1;
@@ -252,6 +254,9 @@ int main(int argc, char *argv[])
 		case 'P':
 			pps = atoi(optarg);
 			break;
+		case 'r':
+			readonly = 1;
+			break;
 		case 's':
 			settime = 1;
 			break;
@@ -308,7 +313,7 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	fd = open(device, O_RDWR);
+	fd = open(device, readonly ? O_RDONLY : O_RDWR);
 	if (fd < 0) {
 		fprintf(stderr, "opening %s: %s\n", device, strerror(errno));
 		return -1;
@@ -436,14 +441,16 @@ int main(int argc, char *argv[])
 	}
 
 	if (extts) {
-		memset(&extts_request, 0, sizeof(extts_request));
-		extts_request.index = index;
-		extts_request.flags = PTP_ENABLE_FEATURE;
-		if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
-			perror("PTP_EXTTS_REQUEST");
-			extts = 0;
-		} else {
-			puts("external time stamp request okay");
+		if (!readonly) {
+			memset(&extts_request, 0, sizeof(extts_request));
+			extts_request.index = index;
+			extts_request.flags = PTP_ENABLE_FEATURE;
+			if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
+				perror("PTP_EXTTS_REQUEST");
+				extts = 0;
+			} else {
+				puts("external time stamp request okay");
+			}
 		}
 		for (; extts; extts--) {
 			cnt = read(fd, &event, sizeof(event));
@@ -455,10 +462,12 @@ int main(int argc, char *argv[])
 			       event.t.sec, event.t.nsec);
 			fflush(stdout);
 		}
-		/* Disable the feature again. */
-		extts_request.flags = 0;
-		if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
-			perror("PTP_EXTTS_REQUEST");
+		if (!readonly) {
+			/* Disable the feature again. */
+			extts_request.flags = 0;
+			if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
+				perror("PTP_EXTTS_REQUEST");
+			}
 		}
 	}
 
