Re: [PATCH net v5 0/4] net: phy: bcm54811: Fix the PHY initialization

From: Kamil Horák (2N)
Date: Fri Jul 04 2025 - 04:41:06 EST




On 7/3/25 12:03, Paolo Abeni wrote:
On 7/3/25 11:03 AM, Kamil Horák (2N) wrote:
On 7/3/25 01:46, Florian Fainelli wrote:
On 7/2/25 15:02, Jakub Kicinski wrote:
On Tue, 1 Jul 2025 09:50:11 +0200 Kamil Horák - 2N wrote:
PATCH 1 - Add MII-Lite PHY interface mode as defined by Broadcom for
    their two-wire PHYs. It can be used with most Ethernet controllers
    under certain limitations (no half-duplex link modes etc.).

PATCH 2 - Add MII-Lite PHY interface type

PATCH 3 - Activation of MII-Lite interface mode on Broadcom bcm5481x
    PHYs

PATCH 4 - Fix the BCM54811 PHY initialization so that it conforms
    to the datasheet regarding a reserved bit in the LRE Control
    register, which must be written to zero after every device reset.
    Also fix the LRE Status register reading, there is another bit to
    be ignored on bcm54811.

I'm a bit lost why the first 3 patches are included in a series for net.
My naive reading is we didn't support this extra mode, now we do,
which sounds like a new feature.. Patch 4, sure, but the dependency
is not obvious.

I don't see the dependency either, at least not in an explicit way.
Kamil, could patch #4 stand on its own and routed through "net" while
patches 1-3 are routed through "net-next"?
It can be done this way, however, even the patch #3 is effectively a
fix, not new feature, because the bcm54811 PHY in MLP package only has
MII-Lite interface available externally. As far I know, there is no BGA
casing available for bcm54811 (unlike bcm54810, that one having both MLP
and BGA). Thus, it cannot function without being switched to MII-Lite
mode. The introduction of MII-Lite itself is clearly a new feature and
it is even (theoretically) available for any MII-capable PHY. So if
putting it all to net it is really impossible or contrary to the
net-next vs. net selection rules, let's divide it....
To get fully functional, bcm54811-based networking, all patches are
necessary so any other user out there must wait for both branches to join.

The above makes sense to me, but I think it would be nice to capture
some of this info in the cover letter - the fact that many people were
confused by the series is an hint the info was indeed missing and required.
OK, tried to write more about it

Please resubmit with an extended cover letter, thanks!
(unless Florian jumps in and explicitly asks for something different :-P)

No such request appeared since yesterday, so submitting an updated text version

Paolo



Kamil