diff --git a/include/uapi/linux/ptp_clock.h b/include/uapi/linux/ptp_clock.h
index d73d83950265dfb315880e0a252e7ac9c6f8431f..1bc794ad957a72729c352ea6eebf40e96b63dffc 100644
--- a/include/uapi/linux/ptp_clock.h
+++ b/include/uapi/linux/ptp_clock.h
@@ -147,7 +147,7 @@ struct ptp_pin_desc {
 #define PTP_SYS_OFFSET_PRECISE \
 	_IOWR(PTP_CLK_MAGIC, 8, struct ptp_sys_offset_precise)
 #define PTP_SYS_OFFSET_EXTENDED \
-	_IOW(PTP_CLK_MAGIC, 9, struct ptp_sys_offset_extended)
+	_IOWR(PTP_CLK_MAGIC, 9, struct ptp_sys_offset_extended)
 
 struct ptp_extts_event {
 	struct ptp_clock_time t; /* Time event occured. */