The MDIO address of the MT7530 and MT7531 switch ICs can be configured
using bootstrap pins. However, there are only 4 possible options for the
switch itself: 7, 15, 23 and 31. As in MediaTek's SDK the address of the
switch is wrongly stated in the device tree as 0 (while in reality it is
31), warn the user about such broken device tree and make a good guess
what was actually intended.
This is imporant also to not break compatibility with older Device Trees
as with commit 868ff5f4944a ("net: dsa: mt7530-mdio: read PHY address of
switch from device tree") the address in device tree will be taken into
account, while before it was hard-coded to 0x1f.
Fixes: b8f126a8d543 ("net-next: dsa: add dsa support for Mediatek MT7530 switch")
Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
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Only tested on BPi-R3 (with various deliberately broken DT) for now!