Re: [PATCH net-next 2/2] net: pcs: xpcs: fix incorrect CL37 AN sequence

From: Vladimir Oltean
Date: Tue Sep 28 2021 - 06:41:10 EST

On Tue, Sep 28, 2021 at 12:19:38PM +0800, Wong Vee Khee wrote:
> According to Synopsys DesignWare Cores Ethernet PCS databook, it is
> required to disable Clause 37 auto-negotiation by programming bit-12
> (AN_ENABLE) to 0 if it is already enabled, before programming various
> fields of VR_MII_AN_CTRL registers.
> After all these programming are done, it is then required to enable
> Clause 37 auto-negotiation by programming bit-12 (AN_ENABLE) to 1.
> Cc: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> Signed-off-by: Wong Vee Khee <vee.khee.wong@xxxxxxxxxxxxxxx>
> ---

Other comments:

- please provide a Fixes: tag, like:

Fixes: b97b5331b8ab ("net: pcs: add C37 SGMII AN support for intel mGbE controller")

(just like that, not split on multiple lines)

- please target the patches to the "net" tree. I see the xpcs_modify
patch has other stuff in its context (nxp_sja1105) that will conflict
with the tree in which the bad commit was originally introduced, so I
think the easiest way would be if you could just open-code the initial
clearing of bit MDIO_AN_CTRL1_ENABLE. You could then wait until "net"
merges with "net-next" again and do the other cleanups afterwards - it
looks like other places could use a _modify method as well, just
looking at DW_VR_MII_AN_CTRL, DW_VR_MII_DIG_CTRL1. Also, the complete
replacement of DW_VR_MII_MMD_CTRL with MDIO_CTRL1 can also be done in
net-next. Just try to keep the fix minimally self-contained.