From: Heiner Kallweit <hkallweit1@gmail.com>
Subject: net: dsa: mv88e6xxx: handle unknown duplex modes gracefully in mv88e6xxx_port_set_duplex
Patch-mainline: v5.1-rc1
Git-commit: c6195a8bdfc62a7cecf7df685e64847a4b700275
References: git-fixes

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@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Denis Kirjanov <dkirjanov@suse.com>
---
 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
@@ -122,7 +122,7 @@ int mv88e6xxx_port_set_link(struct mv88e
 		/* normal link detection */
 		break;
 	default:
-		return -EINVAL;
+		return -EOPNOTSUPP;
 	}
 
 	err = mv88e6xxx_port_write(chip, port, PORT_PCS_CTRL, reg);