Man page 9 : get_phy_device

get_phy_device - reads the specified PHY device and returns its phy_device struct

struct phy_device * get_phy_device(struct mii_bus *  bus , int  addr , bool  is_c45 );

bus
    the target MII bus

addr
    PHY address on the MII bus

is_c45
    If true the PHY uses the 802.3 clause 45 protocol

Reads the ID registers of the PHY at addr on the bus, then allocates and returns the phy_device to represent it.