net: phy: broadcom: add bcm_phy_modify_exp()

Add the convenience function to do a read-modify-write. This has the
additional benefit of saving one write to the selection register.
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/bcm-phy-lib.c

@@ -67,6 +67,38 @@ int bcm_phy_read_exp(struct phy_device *phydev, u16 reg)
 }
 EXPORT_SYMBOL_GPL(bcm_phy_read_exp);
 
+int __bcm_phy_modify_exp(struct phy_device *phydev, u16 reg, u16 mask, u16 set)
+{
+	int new, ret;
+
+	ret = __phy_write(phydev, MII_BCM54XX_EXP_SEL, reg);
+	if (ret < 0)
+		return ret;
+
+	ret = __phy_read(phydev, MII_BCM54XX_EXP_DATA);
+	if (ret < 0)
+		return ret;
+
+	new = (ret & ~mask) | set;
+	if (new == ret)
+		return 0;
+
+	return __phy_write(phydev, MII_BCM54XX_EXP_DATA, new);
+}
+EXPORT_SYMBOL_GPL(__bcm_phy_modify_exp);
+
+int bcm_phy_modify_exp(struct phy_device *phydev, u16 reg, u16 mask, u16 set)
+{
+	int ret;
+
+	phy_lock_mdio_bus(phydev);
+	ret = __bcm_phy_modify_exp(phydev, reg, mask, set);
+	phy_unlock_mdio_bus(phydev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(bcm_phy_modify_exp);
+
 int bcm54xx_auxctl_read(struct phy_device *phydev, u16 regnum)
 {
 	/* The register must be written to both the Shadow Register Select and

drivers/net/phy/bcm-phy-lib.h

@@ -29,8 +29,10 @@
 
 int __bcm_phy_write_exp(struct phy_device *phydev, u16 reg, u16 val);
 int __bcm_phy_read_exp(struct phy_device *phydev, u16 reg);
+int __bcm_phy_modify_exp(struct phy_device *phydev, u16 reg, u16 mask, u16 set);
 int bcm_phy_write_exp(struct phy_device *phydev, u16 reg, u16 val);
 int bcm_phy_read_exp(struct phy_device *phydev, u16 reg);
+int bcm_phy_modify_exp(struct phy_device *phydev, u16 reg, u16 mask, u16 set);
 
 static inline int bcm_phy_write_exp_sel(struct phy_device *phydev,
 					u16 reg, u16 val)