net: phy: clear link parameters on admin link down

When a PHY is halted (e.g. `ip link set dev lan2 down`), several
fields in struct phy_device may still reflect the last active
connection. This leads to ethtool showing stale values even though
the link is down.

Reset selected fields in _phy_state_machine() when transitioning
to PHY_HALTED and the link was previously up:

- speed/duplex -> UNKNOWN, but only in autoneg mode (in forced mode
  these fields carry configuration, not status)
- master_slave_state -> UNKNOWN if previously supported
- mdix -> INVALID (state only, same meaning as "unknown")
- lp_advertising -> always cleared

The cleanup is skipped if the PHY is in PHY_ERROR state, so the
last values remain available for diagnostics.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250917094751.2101285-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions