How to access the phy layer under the Linux hardware registers, and how to use drive function-CodePudding

Am335 series development board, so the chip with dp83640, now the whole network can run, but I want to change the contents of the register dp83640 chip, as well as about dp83640 driver, how to make, like a character device we can use the open function to open the device, then use the write functions such as operations, but this not so chip device name, only the eth0 network device node, how do I access to the dp83640? And how to use the inside of the drive function? Please great god answers,

 static struct phy_driver dp83640_driver={
Phy_id=DP83640_PHY_ID, 
Xfffffff0 phy_id_mask=0, 
.name="NatSemi DP83640," 
The features=PHY_BASIC_FEATURES, 
. The flags=0, 
The probe=dp83640_probe, 
Remove=dp83640_remove, 
Config_aneg=genphy_config_aneg, 
Read_status=genphy_read_status, 
Hwtstamp=dp83640_hwtstamp, 
Rxtstamp=dp83640_rxtstamp, 
Txtstamp=dp83640_txtstamp, 
. The driver={owner=THIS_MODULE,} 
};