diff --git a/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h b/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h
index 6033f2f6260a464418fcc981e5430e155e836bc3..166b513ff751b65bb61c7be40cdb7a8cf76ccf56 100644
--- a/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h
+++ b/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h
@@ -944,6 +944,11 @@ static inline unsigned int mv88e6xxx_num_ports(struct mv88e6xxx_chip *chip)
 	return chip->info->num_ports;
 }
 
+static inline u16 mv88e6xxx_port_mask(struct mv88e6xxx_chip *chip)
+{
+	return GENMASK(mv88e6xxx_num_ports(chip) - 1, 0);
+}
+
 int mv88e6xxx_read(struct mv88e6xxx_chip *chip, int addr, int reg, u16 *val);
 int mv88e6xxx_write(struct mv88e6xxx_chip *chip, int addr, int reg, u16 val);
 int mv88e6xxx_update(struct mv88e6xxx_chip *chip, int addr, int reg,
diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index 8875784c4718feee699355f91c2092622417cce1..9bb0f2134cba76bc3f9daff0d4cafcfe6d49a4d3 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -539,7 +539,7 @@ int mv88e6351_port_set_egress_unknowns(struct mv88e6xxx_chip *chip, int port,
 
 int mv88e6xxx_port_set_vlan_map(struct mv88e6xxx_chip *chip, int port, u16 map)
 {
-	const u16 mask = GENMASK(mv88e6xxx_num_ports(chip) - 1, 0);
+	const u16 mask = mv88e6xxx_port_mask(chip);
 	u16 reg;
 	int err;