net: phy: fix MDIO bus PM PHY resuming

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: 503ba7c69610 ("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>
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index c8b0c34..28e3c5c 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -286,6 +286,8 @@
 	if (!mdio_bus_phy_may_suspend(phydev))
 		return 0;
 
+	phydev->suspended_by_mdio_bus = 1;
+
 	return phy_suspend(phydev);
 }
 
@@ -294,9 +296,11 @@
 	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 = 0;
+
 	ret = phy_resume(phydev);
 	if (ret < 0)
 		return ret;
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 22f5e76..452e8ba 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -357,6 +357,7 @@
  * is_gigabit_capable: Set to true if PHY supports 1000Mbps
  * 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.
  * sysfs_links: Internal boolean tracking sysfs symbolic links setup/removal.
  * loopback_enabled: Set true if this phy has been loopbacked successfully.
  * state: state of the PHY for management purposes
@@ -396,6 +397,7 @@
 	unsigned is_gigabit_capable:1;
 	unsigned has_fixups:1;
 	unsigned suspended:1;
+	unsigned suspended_by_mdio_bus:1;
 	unsigned sysfs_links:1;
 	unsigned loopback_enabled:1;