Re: [PATCH net-next RFC 8/9] net: dsa: mv88e6xxx: add rx/tx timestamping support

[Richard Cochran]

On Thu, Sep 28, 2017 at 10:25:40AM -0500, Brandon Streiff wrote:
> We also utilize a feature of the "generation 3" PTP hardware that lets
> us to embed the timestamp value into one of the reserved fields in the
> PTP header. This lets us extract the timestamp out of the header and
> avoid an SMI access in the RX codepath. (This implementation does not
> presently support the older generations.)

That is fine for the later models, but we really need the code to read
over MDIO as well.  You added .ptp_support = true for those older
switches, and so the present series won't work.

If it helps, maybe I can adapt the relevant code from my driver to
your work.

Thanks,
Richard