Article on PHY API

Hello,

I’m posting a request for article which would cover the PHY when writing
network driver. The only source of information on that is Network DDK pcnet
driver source. Which functions are in PHY api, what’s the purpose of them?

Also do I need to initialize the phy if my driver is “software emulated”, i
mean virtual driver, which does not have any hardware, but simply transmits
the data through /dev/serX, for ex.

Thanks in advance,

Arunas