net: phy: microchip: Use genphy_soft_reset() to purge stale LPA bits

Enable .soft_reset for the LAN88xx PHY driver by assigning
genphy_soft_reset() to ensure that the phylib core performs a proper
soft reset during reconfiguration.

Previously, the driver left .soft_reset unimplemented, so calls to
phy_init_hw() (e.g., from lan88xx_link_change_notify()) did not fully
reset the PHY. As a result, stale contents in the Link Partner Ability
(LPA) register could persist, causing the PHY to incorrectly report
that the link partner advertised autonegotiation even when it did not.

Using genphy_soft_reset() guarantees a clean reset of the PHY and
corrects the false autoneg reporting in these scenarios.

Fixes: ccb989e ("net: phy: microchip: Reset LAN88xx PHY to ensure clean link state on LAN7800/7850")
Signed-off-by: Oleksij Rempel <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: olerem

drivers/net/phy/microchip.c

@@ -488,6 +488,7 @@ static struct phy_driver microchip_phy_driver[] = {
 	.config_init	= lan88xx_config_init,
 	.config_aneg	= lan88xx_config_aneg,
 	.link_change_notify = lan88xx_link_change_notify,
+	.soft_reset	= genphy_soft_reset,
 
 	/* Interrupt handling is broken, do not define related
 	 * functions to force polling.