net: usb: lan78xx: scan all MDIO addresses on LAN7801

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[ Upstream commit f1e2f0ce70 ]

The LAN7801 is designed exclusively for external PHYs (unlike the
LAN7800/LAN7850 which have internal PHYs), but lan78xx_mdio_init()
restricts PHY scanning to MDIO addresses 0-7 by setting phy_mask to
~(0xFF). This prevents discovery of external PHYs wired to addresses
outside that range.

One such case is the DP83TC814 100BASE-T1 PHY, which is typically
configured at MDIO address 10 via PHYAD bootstrap pins and goes
undetected with the current mask.

Remove the restrictive phy_mask assignment for the LAN7801 so that the
default mask of 0 applies, allowing all 32 MDIO addresses to be
scanned during bus registration.

Fixes: 02dc1f3d61 ("lan78xx: add LAN7801 MAC only support")
Signed-off-by: Martin Pålsson <martin@poleshift.se>
Link: https://patch.msgid.link/0110019c6f388aff-98d99cf0-4425-4fff-b16b-dea5ad8fafe0-000000@eu-north-1.amazonses.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Martin Pålsson 2026-02-18 05:28:22 +00:00 • committed by Sasha Levin

parent fc393af769

commit f3970be26a

1 changed files with 0 additions and 2 deletions

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drivers/net/usb/lan78xx.c

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