net: mdiobus: add APIs for modifying a MDIO device register

Add APIs for modifying a MDIO device register, similar to the existing
phy_modify() group of functions, but at mdiobus level instead.  Adapt
__phy_modify_changed() to use the new mdiobus level helper.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/phy.h b/include/linux/phy.h
index ac956ea1a87c..8f73e4ea288c 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -753,6 +753,25 @@ static inline int __phy_write(struct phy_device *phydev, u32 regnum, u16 val)
 }
 
 /**
+ * __phy_modify_changed() - Convenience function for modifying a PHY register
+ * @phydev: a pointer to a &struct phy_device
+ * @regnum: register number
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ *
+ * Unlocked helper function which allows a PHY register to be modified as
+ * new register value = (old register value & ~mask) | set
+ *
+ * Returns negative errno, 0 if there was no change, and 1 in case of change
+ */
+static inline int __phy_modify_changed(struct phy_device *phydev, u32 regnum,
+				       u16 mask, u16 set)
+{
+	return __mdiobus_modify_changed(phydev->mdio.bus, phydev->mdio.addr,
+					regnum, mask, set);
+}
+
+/**
  * phy_read_mmd - Convenience function for reading a register
  * from an MMD on a given PHY.
  * @phydev: The phy_device struct