net: dsa: mv88e6xxx: wait after reset deactivation

[ Upstream commit 7b75e49d ]

Add a 1ms delay after reset deactivation. Otherwise the chip returns
bogus ID value. This is observed with 88E6390 (Peridot) chip.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/dsa/mv88e6xxx/chip.c

@@ -4910,6 +4910,8 @@ static int mv88e6xxx_probe(struct mdio_device *mdiodev)
 		err = PTR_ERR(chip->reset);
 		goto out;
 	}
+	if (chip->reset)
+		usleep_range(1000, 2000);
 
 	err = mv88e6xxx_detect(chip);
 	if (err)