Re: [PATCH] net: phy: mscc: enable MAC SerDes autonegotiation

From: Andrew Lunn
Date: Mon Feb 07 2022 - 21:10:43 EST


> MAC implementation[1] in a lot of NXP SoCs comes with in-band aneg enabled
> by default, and it does expect Clause 37 auto-negotiation to complete
> between MAC and PHY before the actual data transfer happens.
>
> [1] https://community.nxp.com/pwmxy87654/attachments/pwmxy87654/t-series/3241/1/AN3869(1).pdf
>
> I faced such issue while integrating VSC85xx PHY
> with one of the recent NXP SoC having similar MAC implementation.
> Not sure if this is a problem on MAC side or PHY side,
> But having Clause 37 support should help in most cases I believe.

So please use this information in the commit message.

The only danger with this change is, is the PHY O.K with auto-neg
turned on, with a MAC which does not actually perform auto-neg? It
could be we have boards which work now because PHY autoneg is turned
off.

Andrew