diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
index 819097d9b583..43f97601b500 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
@@ -243,6 +243,12 @@ static int mlx5_extts_configure(struct ptp_clock_info *ptp,
 				PTP_STRICT_FLAGS))
 		return -EOPNOTSUPP;
 
+	/* Reject requests to enable time stamping on both edges. */
+	if ((rq->extts.flags & PTP_STRICT_FLAGS) &&
+	    (rq->extts.flags & PTP_ENABLE_FEATURE) &&
+	    (rq->extts.flags & PTP_EXTTS_EDGES) == PTP_EXTTS_EDGES)
+		return -EOPNOTSUPP;
+
 	if (rq->extts.index >= clock->ptp_info.n_pins)
 		return -EINVAL;