phy: power management support

This patch adds the power management support into the physical
abstraction layer.

Suspend and resume functions respectively turns on/off the bit 11
into the PHY Basic mode control register.
Generic PHY device starts supporting PM.

In order to support the wake-on LAN and avoid to put in power down
the PHY device, the MDIO is aware of what the Ethernet device wants to do.

Voluntary, no CONFIG_PM defines were added into the sources.
Also generic suspend/resume functions are exported to allow
other drivers use them (such as genphy_config_aneg etc.).

Within the phy_driver_register function, we need to remove the
memset. It overrides the device driver owner and it is not good.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 868812f..8755d8c 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -284,9 +284,12 @@
 {
 	int ret = 0;
 	struct device_driver *drv = dev->driver;
+	struct phy_driver *phydrv = to_phy_driver(drv);
+	struct phy_device *phydev = to_phy_device(dev);
 
-	if (drv && drv->suspend)
-		ret = drv->suspend(dev, state);
+	if ((!device_may_wakeup(phydev->dev.parent)) &&
+		(phydrv && phydrv->suspend))
+			ret = phydrv->suspend(phydev);
 
 	return ret;
 }
@@ -295,9 +298,12 @@
 {
 	int ret = 0;
 	struct device_driver *drv = dev->driver;
+	struct phy_driver *phydrv = to_phy_driver(drv);
+	struct phy_device *phydev = to_phy_device(dev);
 
-	if (drv && drv->resume)
-		ret = drv->resume(dev);
+	if ((!device_may_wakeup(phydev->dev.parent)) &&
+		(phydrv && phydrv->resume))
+		ret = phydrv->resume(phydev);
 
 	return ret;
 }