Expose the PHY device interface mode through sysfs since this is an
useful piece of information for knowing how the attached networking
device will have configured its transmit/receive path.
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This adds a phy_id sysfs attribute to MDIO devices, containing the
32-bit PHY identifier reported by the device.  This attribute can
be useful when debugging problems related to phy drivers.  Other
enumerable buses already have similar attributes.
Signed-off-by: NNick Bowler <nbowler@elliptictech.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>