diff --git a/msg.h b/msg.h
index cd07c55..5da50e1 100644
--- a/msg.h
+++ b/msg.h
@@ -27,6 +27,7 @@
 #include "address.h"
 #include "ddt.h"
 #include "tlv.h"
+#include "tmv.h"
 
 #define PTP_VERSION 2
 
@@ -65,7 +66,7 @@ enum timestamp_type {
 struct hw_timestamp {
 	enum timestamp_type type;
 	tmv_t ts;
-	struct timespec sw;
+	tmv_t sw;
 };
 
 enum controlField {
diff --git a/port.c b/port.c
index 08eb363..17ae5cd 100644
--- a/port.c
+++ b/port.c
@@ -555,8 +555,8 @@ static void free_foreign_masters(struct port *p)
 static int fup_sync_ok(struct ptp_message *fup, struct ptp_message *sync)
 {
 	int64_t tfup, tsync;
-	tfup = tmv_to_nanoseconds(timespec_to_tmv(fup->hwts.sw));
-	tsync = tmv_to_nanoseconds(timespec_to_tmv(sync->hwts.sw));
+	tfup = tmv_to_nanoseconds(fup->hwts.sw);
+	tsync = tmv_to_nanoseconds(sync->hwts.sw);
 	/*
 	 * NB - If the sk_check_fupsync option is not enabled, then
 	 * both of these time stamps will be zero.
diff --git a/sk.c b/sk.c
index a1a695e..72926ab 100644
--- a/sk.c
+++ b/sk.c
@@ -341,7 +341,7 @@ int sk_receive(int fd, void *buf, int buflen,
 				return -1;
 			}
 			sw = (struct timespec *) CMSG_DATA(cm);
-			hwts->sw = *sw;
+			hwts->sw = timespec_to_tmv(*sw);
 		}
 	}