When the hardware platform goes down for reboot, there's always the
chance that the PHY device doesn't get reset, or fully reconfigured by
the bootloader, which could rely on strap settings.

Therefore, when special modes from the PHY are being used, which could
make it non-functional at reboot, introduce a phy_shutdown helper to
pull the PHY out of the non-functional mode it is currently in.

Currently, this applies to the isolation mode.

Suggested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
V2 : New patch

 drivers/net/phy/phy_device.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index c468e72bef4b..a0d8ff995024 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -3733,6 +3733,17 @@ static int phy_remove(struct device *dev)
 	return 0;
 }
 
+static void phy_shutdown(struct device *dev)
+{
+	struct phy_device *phydev = to_phy_device(dev);
+
+	/* If the PHY isn't reset and reconfigured by the bootloader, the PHY
+	 * will stay isolated. Make sure to un-isolate PHYs during shutdown.
+	 */
+	if (phydev->isolated)
+		phy_isolate(phydev, false);
+}
+
 /**
  * phy_driver_register - register a phy_driver with the PHY layer
  * @new_driver: new phy_driver to register
@@ -3766,6 +3777,7 @@ int phy_driver_register(struct phy_driver *new_driver, struct module *owner)
 	new_driver->mdiodrv.driver.bus = &mdio_bus_type;
 	new_driver->mdiodrv.driver.probe = phy_probe;
 	new_driver->mdiodrv.driver.remove = phy_remove;
+	new_driver->mdiodrv.driver.shutdown = phy_shutdown;
 	new_driver->mdiodrv.driver.owner = owner;
 	new_driver->mdiodrv.driver.probe_type = PROBE_FORCE_SYNCHRONOUS;
 
-- 
2.46.1