says:
====================
net: phy: bcm54811: PHY initialization
Proper bcm54811 PHY driver initialization for MII-Lite.
The bcm54811 PHY in MLP package must be setup for MII-Lite interface
mode by software. Normally, the PHY to MAC interface is selected in
hardware by setting the bootstrap pins of the PHY. However, MII and
MII-Lite share the same hardware setup and must be distinguished by
software, setting appropriate bit in a configuration register.
The MII-Lite interface mode is non-standard one, defined by Broadcom
for some of their PHYs. The MII-Lite lightness consist in omitting
RXER, TXER, CRS and COL signals of the standard MII interface.
Absence of COL them makes half-duplex links modes impossible but
does not interfere with Broadcom's BroadR-Reach link modes, because
they are full-duplex only.
To do it in a clean way, MII-Lite must be introduced first, including
its limitation to link modes (no half-duplex), because it is a
prerequisite for the patch #3 of this series. The patch #4 does not
depend on MII-Lite directly but both #3 and #4 are necessary for
bcm54811 to work properly without additional configuration steps to be
done - for example in the bootloader, before the kernel starts.
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 - Initialize the BCM54811 PHY properly 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.
Ignore the LDS capability bit in LRE Status register on bcm54811.
====================
Link: https://patch.msgid.link/20250708090140.61355-1-kamilh@axis.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>