MII_BCM54XX_EXP_EXP75
err = bcm_phy_write_exp(phydev, MII_BCM54XX_EXP_EXP75,
val = bcm_phy_read_exp(phydev, MII_BCM54XX_EXP_EXP75);
err = bcm_phy_write_exp(phydev, MII_BCM54XX_EXP_EXP75, val);