EMAC driver: add power down mode

This patch puts phy in power-down mode when interface is down.
Also we should think about energy detect power-down mode, that will
decrease power consumption when no link.

Signed-off-by: Vitja Makarov <vitja.makarov@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bfin_mac.c

@@ -884,10 +884,10 @@ static int bf537mac_open(struct net_device *dev)
 		return retval;
 
 	phy_start(lp->phydev);
+	phy_write(lp->phydev, MII_BMCR, BMCR_RESET);
 	setup_system_regs(dev);
 	bf537mac_disable();
 	bf537mac_enable();
-
 	pr_debug("hardware init finished\n");
 	netif_start_queue(dev);
 	netif_carrier_on(dev);
@@ -910,6 +910,7 @@ static int bf537mac_close(struct net_device *dev)
 	netif_carrier_off(dev);
 
 	phy_stop(lp->phydev);
+	phy_write(lp->phydev, MII_BMCR, BMCR_PDOWN);
 
 	/* clear everything */
 	bf537mac_shutdown(dev);