Add genphy_c45_config_aneg() function to phy-c45.c

Commit 34786005 ("net: phy: prevent PHYs w/o Clause 22 regs from calling
genphy_config_aneg") introduced a check that aborts phy_config_aneg()
if the phy is a C45 phy.
This causes phy_state_machine() to call phy_error() so that the phy
ends up in PHY_HALTED state.

Instead of returning -EOPNOTSUPP, call genphy_c45_config_aneg()
(analogous to the C22 case) so that the state machine can run
correctly.

genphy_c45_config_aneg() closely resembles mv3310_config_aneg()
in drivers/net/phy/marvell10g.c, excluding vendor specific
configurations for 1000BaseT.

Fixes: 22b56e82 ("net: phy: replace genphy_10g_driver with genphy_c45_driver")
Signed-off-by: Marco Hartmann <marco.hartmann@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phy-c45.c

@@ -523,6 +523,32 @@ int genphy_c45_read_status(struct phy_device *phydev)
 }
 EXPORT_SYMBOL_GPL(genphy_c45_read_status);
 
+/**
+ * genphy_c45_config_aneg - restart auto-negotiation or forced setup
+ * @phydev: target phy_device struct
+ *
+ * Description: If auto-negotiation is enabled, we configure the
+ *   advertising, and then restart auto-negotiation.  If it is not
+ *   enabled, then we force a configuration.
+ */
+int genphy_c45_config_aneg(struct phy_device *phydev)
+{
+	bool changed = false;
+	int ret;
+
+	if (phydev->autoneg == AUTONEG_DISABLE)
+		return genphy_c45_pma_setup_forced(phydev);
+
+	ret = genphy_c45_an_config_aneg(phydev);
+	if (ret < 0)
+		return ret;
+	if (ret > 0)
+		changed = true;
+
+	return genphy_c45_check_and_restart_aneg(phydev, changed);
+}
+EXPORT_SYMBOL_GPL(genphy_c45_config_aneg);
+
 /* The gen10g_* functions are the old Clause 45 stub */
 
 int gen10g_config_aneg(struct phy_device *phydev)

drivers/net/phy/phy.c

@@ -507,7 +507,7 @@ static int phy_config_aneg(struct phy_device *phydev)
 	 * allowed to call genphy_config_aneg()
 	 */
 	if (phydev->is_c45 && !(phydev->c45_ids.devices_in_package & BIT(0)))
-		return -EOPNOTSUPP;
+		return genphy_c45_config_aneg(phydev);
 
 	return genphy_config_aneg(phydev);
 }

include/linux/phy.h

@@ -1107,6 +1107,7 @@ int genphy_c45_an_disable_aneg(struct phy_device *phydev);
 int genphy_c45_read_mdix(struct phy_device *phydev);
 int genphy_c45_pma_read_abilities(struct phy_device *phydev);
 int genphy_c45_read_status(struct phy_device *phydev);
+int genphy_c45_config_aneg(struct phy_device *phydev);
 
 /* The gen10g_* functions are the old Clause 45 stub */
 int gen10g_config_aneg(struct phy_device *phydev);