net: phy: broadcom: Move bcm54xx_auxctl_{read, write} to common library

We are going to need these functions to implement support for Broadcom
Wirespeed, aka downshift.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/phy/bcm-phy-lib.c b/drivers/net/phy/bcm-phy-lib.c
index df0416d..18e11b3 100644
--- a/drivers/net/phy/bcm-phy-lib.c
+++ b/drivers/net/phy/bcm-phy-lib.c
@@ -50,6 +50,23 @@ int bcm_phy_read_exp(struct phy_device *phydev, u16 reg)
 }
 EXPORT_SYMBOL_GPL(bcm_phy_read_exp);
 
+int bcm54xx_auxctl_read(struct phy_device *phydev, u16 regnum)
+{
+	/* The register must be written to both the Shadow Register Select and
+	 * the Shadow Read Register Selector
+	 */
+	phy_write(phydev, MII_BCM54XX_AUX_CTL, regnum |
+		  regnum << MII_BCM54XX_AUXCTL_SHDWSEL_READ_SHIFT);
+	return phy_read(phydev, MII_BCM54XX_AUX_CTL);
+}
+EXPORT_SYMBOL_GPL(bcm54xx_auxctl_read);
+
+int bcm54xx_auxctl_write(struct phy_device *phydev, u16 regnum, u16 val)
+{
+	return phy_write(phydev, MII_BCM54XX_AUX_CTL, regnum | val);
+}
+EXPORT_SYMBOL(bcm54xx_auxctl_write);
+
 int bcm_phy_write_misc(struct phy_device *phydev,
 		       u16 reg, u16 chl, u16 val)
 {