diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index 92945841c8e882e0e582372778d5c81603052236..2c75460ad57aa4d50301580e0494b6aa64a71d2d 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -190,7 +190,7 @@ int mv88e6xxx_port_set_duplex(struct mv88e6xxx_chip *chip, int port, int dup)
 		/* normal duplex detection */
 		break;
 	default:
-		return -EINVAL;
+		return -EOPNOTSUPP;
 	}
 
 	err = mv88e6xxx_port_write(chip, port, MV88E6XXX_PORT_MAC_CTL, reg);