[PATCH 4.20 20/76] net: dsa: mv88e6xxx: handle unknown duplex modes gracefully in mv88e6xxx_port_set_duplex

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heiner Kallweit <hkallweit1@xxxxxxxxx>

[ Upstream commit c6195a8bdfc62a7cecf7df685e64847a4b700275 ]

When testing another issue I faced the problem that
mv88e6xxx_port_setup_mac() failed due to DUPLEX_UNKNOWN being passed
as argument to mv88e6xxx_port_set_duplex(). We should handle this case
gracefully and return -EOPNOTSUPP, like e.g. mv88e6xxx_port_set_speed()
is doing it.

Fixes: 7f1ae07b51e8 ("net: dsa: mv88e6xxx: add port duplex setter")
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/dsa/mv88e6xxx/port.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -190,7 +190,7 @@ int mv88e6xxx_port_set_duplex(struct mv8
 		/* normal duplex detection */
 		break;
 	default:
-		return -EINVAL;
+		return -EOPNOTSUPP;
 	}
 
 	err = mv88e6xxx_port_write(chip, port, MV88E6XXX_PORT_MAC_CTL, reg);