net: mdio: Add RTL9300 MDIO driver
Add a driver for the MDIO controller on the RTL9300 family of Ethernet
switches with integrated SoC. There are 4 physical SMI interfaces on the
RTL9300 however access is done using the switch ports. The driver takes
the MDIO bus hierarchy from the DTS and uses this to configure the
switch ports so they are associated with the correct PHY. This mapping
is also used when dealing with software requests from phylib.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250409231554.3943115-1-chris.packham@alliedtelesis.co.nz
Signed-off-by: Paolo Abeni <pabeni@redhat.com>