net: phylink: add interface to configure clause 22 PCS PHY

Add an interface to configure the advertisement for a clause 22 PCS
PHY, and set the AN enable flag in the BMCR appropriately.
Reviewed-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/phy/phylink.c

@@ -2442,6 +2442,43 @@ int phylink_mii_c22_pcs_set_advertisement(struct mdio_device *pcs,
 }
 EXPORT_SYMBOL_GPL(phylink_mii_c22_pcs_set_advertisement);
 
+/**
+ * phylink_mii_c22_pcs_config() - configure clause 22 PCS
+ * @pcs: a pointer to a &struct mdio_device.
+ * @mode: link autonegotiation mode
+ * @interface: the PHY interface mode being configured
+ * @advertising: the ethtool advertisement mask
+ *
+ * Configure a Clause 22 PCS PHY with the appropriate negotiation
+ * parameters for the @mode, @interface and @advertising parameters.
+ * Returns negative error number on failure, zero if the advertisement
+ * has not changed, or positive if there is a change.
+ */
+int phylink_mii_c22_pcs_config(struct mdio_device *pcs, unsigned int mode,
+			       phy_interface_t interface,
+			       const unsigned long *advertising)
+{
+	bool changed;
+	u16 bmcr;
+	int ret;
+
+	ret = phylink_mii_c22_pcs_set_advertisement(pcs, interface,
+						    advertising);
+	if (ret < 0)
+		return ret;
+
+	changed = ret > 0;
+
+	bmcr = mode == MLO_AN_INBAND ? BMCR_ANENABLE : 0;
+	ret = mdiobus_modify(pcs->bus, pcs->addr, MII_BMCR,
+			     BMCR_ANENABLE, bmcr);
+	if (ret < 0)
+		return ret;
+
+	return changed ? 1 : 0;
+}
+EXPORT_SYMBOL_GPL(phylink_mii_c22_pcs_config);
+
 /**
  * phylink_mii_c22_pcs_an_restart() - restart 802.3z autonegotiation
  * @pcs: a pointer to a &struct mdio_device.

include/linux/phylink.h

@@ -478,6 +478,9 @@ void phylink_mii_c22_pcs_get_state(struct mdio_device *pcs,
 int phylink_mii_c22_pcs_set_advertisement(struct mdio_device *pcs,
 					  phy_interface_t interface,
 					  const unsigned long *advertising);
+int phylink_mii_c22_pcs_config(struct mdio_device *pcs, unsigned int mode,
+			       phy_interface_t interface,
+			       const unsigned long *advertising);
 void phylink_mii_c22_pcs_an_restart(struct mdio_device *pcs);
 
 void phylink_mii_c45_pcs_get_state(struct mdio_device *pcs,