+/**
+ * phy_mmd_start_indirect - Convenience function for writing MMD registers
+ * @phydev: the phy_device struct
+ * @devad: The MMD to read from
+ * @regnum: register number to write
+ * @return: None
+ */
+static inline void phy_mmd_start_indirect(struct phy_device *phydev, int devad,
+ int regnum)
+{
+ /* Write the desired MMD Devad */
+ phy_write(phydev, MDIO_DEVAD_NONE, MII_MMD_CTRL, devad);
+
+ /* Write the desired MMD register address */
+ phy_write(phydev, MDIO_DEVAD_NONE, MII_MMD_DATA, regnum);
+
+ /* Select the Function : DATA with no post increment */
+ phy_write(phydev, MDIO_DEVAD_NONE, MII_MMD_CTRL,
+ (devad | MII_MMD_CTRL_NOINCR));
+}
+
+/**
+ * phy_read_mmd - Convenience function for reading a register
+ * from an MMD on a given PHY.
+ * @phydev: The phy_device struct
+ * @devad: The MMD to read from
+ * @regnum: The register on the MMD to read
+ * @return: Value for success or negative errno for failure
+ */
+static inline int phy_read_mmd(struct phy_device *phydev, int devad,
+ int regnum)
+{
+ struct phy_driver *drv = phydev->drv;
+
+ if (regnum > (u16)~0 || devad > 32)
+ return -EINVAL;
+
+ /* driver-specific access */
+ if (drv->read_mmd)
+ return drv->read_mmd(phydev, devad, regnum);
+
+ /* direct C45 / C22 access */
+ if ((drv->features & PHY_10G_FEATURES) == PHY_10G_FEATURES ||
+ devad == MDIO_DEVAD_NONE || !devad)
+ return phy_read(phydev, devad, regnum);
+
+ /* indirect C22 access */
+ phy_mmd_start_indirect(phydev, devad, regnum);
+
+ /* Read the content of the MMD's selected register */
+ return phy_read(phydev, MDIO_DEVAD_NONE, MII_MMD_DATA);
+}
+
+/**
+ * phy_write_mmd - Convenience function for writing a register
+ * on an MMD on a given PHY.
+ * @phydev: The phy_device struct
+ * @devad: The MMD to read from
+ * @regnum: The register on the MMD to read
+ * @val: value to write to @regnum
+ * @return: 0 for success or negative errno for failure
+ */
+static inline int phy_write_mmd(struct phy_device *phydev, int devad,
+ int regnum, u16 val)
+{
+ struct phy_driver *drv = phydev->drv;
+
+ if (regnum > (u16)~0 || devad > 32)
+ return -EINVAL;
+
+ /* driver-specific access */
+ if (drv->write_mmd)
+ return drv->write_mmd(phydev, devad, regnum, val);
+
+ /* direct C45 / C22 access */
+ if ((drv->features & PHY_10G_FEATURES) == PHY_10G_FEATURES ||
+ devad == MDIO_DEVAD_NONE || !devad)
+ return phy_write(phydev, devad, regnum, val);
+
+ /* indirect C22 access */
+ phy_mmd_start_indirect(phydev, devad, regnum);
+
+ /* Write the data into MMD's selected register */
+ return phy_write(phydev, MDIO_DEVAD_NONE, MII_MMD_DATA, val);
+}
+
+/**
+ * phy_set_bits_mmd - Convenience function for setting bits in a register
+ * on MMD
+ * @phydev: the phy_device struct
+ * @devad: the MMD containing register to modify
+ * @regnum: register number to modify
+ * @val: bits to set
+ * @return: 0 for success or negative errno for failure
+ */
+static inline int phy_set_bits_mmd(struct phy_device *phydev, int devad,
+ u32 regnum, u16 val)
+{
+ int value, ret;
+
+ value = phy_read_mmd(phydev, devad, regnum);
+ if (value < 0)
+ return value;
+
+ value |= val;
+
+ ret = phy_write_mmd(phydev, devad, regnum, value);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+/**
+ * phy_clear_bits_mmd - Convenience function for clearing bits in a register
+ * on MMD
+ * @phydev: the phy_device struct
+ * @devad: the MMD containing register to modify
+ * @regnum: register number to modify
+ * @val: bits to clear
+ * @return: 0 for success or negative errno for failure
+ */
+static inline int phy_clear_bits_mmd(struct phy_device *phydev, int devad,
+ u32 regnum, u16 val)
+{
+ int value, ret;
+
+ value = phy_read_mmd(phydev, devad, regnum);
+ if (value < 0)
+ return value;
+
+ value &= ~val;
+
+ ret = phy_write_mmd(phydev, devad, regnum, value);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+