Subject: Re: [RFC 04/11] net: phy: Handle c22 regs presence better

From: Andrew Lunn <[email-masked]>
Date: Tue, 26 May 2020 00:06:14 +0200

> Yes, we know even for the NXP reference hardware, one of the phy's doesn't
> probe out correctly because it doesn't respond to the ieee defined
> registers. I think at this point, there really isn't anything we can do
> about that unless we involve the (ACPI) firmware in currently nonstandard
> behaviors.
> 
> So, my goals here have been to first, not break anything, and then do a
> slightly better job finding phy's that are (mostly?) responding correctly to
> the 802.3 spec. So we can say "if you hardware is ACPI conformant, and you
> have IEEE conformant phy's you should be ok". So, for your example phy, I
> guess the immediate answer is "use DT" or "find a conformant phy", or even
> "abstract it in the firmware and use a mailbox interface".
 
Hi Jeremy

You need to be careful here, when you say "use DT". With a c45 PHY
of_mdiobus_register_phy() calls get_phy_device() to see if the device
exists on the bus. So your changes to get_phy_device() etc, needs to
continue to find devices it used to find, even if they are not fully
complient to 802.3.

	  Andrew