net: phy: fix MDIO bus PM PHY resuming

[ Upstream commit 611d779a ]

So far we have the unfortunate situation that mdio_bus_phy_may_suspend()
is called in suspend AND resume path, assuming that function result is
the same. After the original change this is no longer the case,
resulting in broken resume as reported by Geert.

To fix this call mdio_bus_phy_may_suspend() in the suspend path only,
and let the phy_device store the info whether it was suspended by
MDIO bus PM.

Fixes: 503ba7c6 ("net: phy: Avoid multiple suspends")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/phy/phy_device.c

@@ -129,6 +129,8 @@ static int mdio_bus_phy_suspend(struct device *dev)
 	if (!mdio_bus_phy_may_suspend(phydev))
 		return 0;
 
+	phydev->suspended_by_mdio_bus = true;
+
 	return phy_suspend(phydev);
 }
 
@@ -137,9 +139,11 @@ static int mdio_bus_phy_resume(struct device *dev)
 	struct phy_device *phydev = to_phy_device(dev);
 	int ret;
 
-	if (!mdio_bus_phy_may_suspend(phydev))
+	if (!phydev->suspended_by_mdio_bus)
 		goto no_resume;
 
+	phydev->suspended_by_mdio_bus = false;
+
 	ret = phy_resume(phydev);
 	if (ret < 0)
 		return ret;

include/linux/phy.h

@@ -333,6 +333,7 @@ struct phy_c45_device_ids {
  * is_pseudo_fixed_link: Set to true if this phy is an Ethernet switch, etc.
  * has_fixups: Set to true if this phy has fixups/quirks.
  * suspended: Set to true if this phy has been suspended successfully.
+ * suspended_by_mdio_bus: Set to true if this phy was suspended by MDIO bus.
  * state: state of the PHY for management purposes
  * dev_flags: Device-specific flags used by the PHY driver.
  * link_timeout: The number of timer firings to wait before the
@@ -369,6 +370,7 @@ struct phy_device {
 	bool is_pseudo_fixed_link;
 	bool has_fixups;
 	bool suspended;
+	bool suspended_by_mdio_bus;
 
 	enum phy_state state;