diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 580cc035536bd..be9b58b2abf9b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
@@ -102,7 +102,7 @@ static int stmmac_adjust_time(struct ptp_clock_info *ptp, s64 delta)
 		time.tv_nsec = priv->plat->est->btr_reserve[0];
 		time.tv_sec = priv->plat->est->btr_reserve[1];
 		basetime = timespec64_to_ktime(time);
-		cycle_time = priv->plat->est->ctr[1] * NSEC_PER_SEC +
+		cycle_time = (u64)priv->plat->est->ctr[1] * NSEC_PER_SEC +
 			     priv->plat->est->ctr[0];
 		time = stmmac_calc_tas_basetime(basetime,
 						current_time_ns,