tg3 / broadcom: Refine AC131 APD support

Auto power-down (APD) support is a power-saving feature.  It should be
selectively enabled since it might expose MAC bugs.  This patch changes
the code to enable APD only if the PHY_BRCM_AUTO_PWRDWN_ENABLE flag is
set.  The tg3 driver was changed to set this bit.
Signed-off-by: NMatt Carlson <mcarlson@broadcom.com>
Reviewed-by: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/phy/broadcom.c

@@ -561,9 +561,11 @@ static int brcm_fet_config_init(struct phy_device *phydev)
 	if (err < 0)
 		goto done;
 
+	if (phydev->dev_flags & PHY_BRCM_AUTO_PWRDWN_ENABLE) {
 		/* Enable auto power down */
 		err = brcm_phy_setbits(phydev, MII_BRCM_FET_SHDW_AUXSTAT2,
 					       MII_BRCM_FET_SHDW_AS2_APDE);
+	}
 
 done:
 	/* Disable shadow register access */

drivers/net/tg3.c

@@ -1114,6 +1114,7 @@ static int tg3_mdio_init(struct tg3 *tp)
 	case TG3_PHY_ID_RTL8201E:
 	case TG3_PHY_ID_BCMAC131:
 		phydev->interface = PHY_INTERFACE_MODE_MII;
+		phydev->dev_flags |= PHY_BRCM_AUTO_PWRDWN_ENABLE;
 		tp->tg3_flags3 |= TG3_FLG3_PHY_IS_FET;
 		break;
 	}