net: phy: micrel: add MDI/MDI-X control support for KSZ9477 switch-integrated PHYs

Add MDI/MDI-X configuration support for PHYs integrated in the KSZ9477
family of Ethernet switches.

All MDI/MDI-X configuration modes are supported:
  - Automatic MDI/MDI-X (ETH_TP_MDI_AUTO)
  - Forced MDI (ETH_TP_MDI)
  - Forced MDI-X (ETH_TP_MDI_X)

However, when operating in automatic mode, the PHY does not expose the
resolved crossover status (i.e., whether MDI or MDI-X is active).
Therefore, in auto mode, the driver reports ETH_TP_MDI_INVALID as
the current status.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250610091354.4060454-2-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 64aa03aed770098744f11cfbed8d9d47602d6223..a51010e644444e2dd27f413bfe8e66e558d9656e 100644 (file)
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -1948,6 +1948,56 @@ static int ksz886x_read_status(struct phy_device *phydev)
        return genphy_read_status(phydev);
 }
 
+static int ksz9477_mdix_update(struct phy_device *phydev)
+{
+       if (phydev->mdix_ctrl != ETH_TP_MDI_AUTO)
+               phydev->mdix = phydev->mdix_ctrl;
+       else
+               phydev->mdix = ETH_TP_MDI_INVALID;
+
+       return 0;
+}
+
+static int ksz9477_read_mdix_ctrl(struct phy_device *phydev)
+{
+       int val;
+
+       val = phy_read(phydev, MII_KSZ9131_AUTO_MDIX);
+       if (val < 0)
+               return val;
+
+       if (!(val & MII_KSZ9131_AUTO_MDIX_SWAP_OFF))
+               phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
+       else if (val & MII_KSZ9131_AUTO_MDI_SET)
+               phydev->mdix_ctrl = ETH_TP_MDI;
+       else
+               phydev->mdix_ctrl = ETH_TP_MDI_X;
+
+       return 0;
+}
+
+static int ksz9477_read_status(struct phy_device *phydev)
+{
+       int ret;
+
+       ret = ksz9477_mdix_update(phydev);
+       if (ret)
+               return ret;
+
+       return genphy_read_status(phydev);
+}
+
+static int ksz9477_config_aneg(struct phy_device *phydev)
+{
+       int ret;
+
+       ret = ksz9131_config_mdix(phydev, phydev->mdix_ctrl);
+       if (ret)
+               return ret;
+
+       return genphy_config_aneg(phydev);
+}
+
 struct ksz9477_errata_write {
        u8 dev_addr;
        u8 reg_addr;
@@ -2029,6 +2079,13 @@ static int ksz9477_config_init(struct phy_device *phydev)
                        return err;
        }
 
+       /* Read initial MDI-X config state. So, we do not need to poll it
+        * later on.
+        */
+       err = ksz9477_read_mdix_ctrl(phydev);
+       if (err)
+               return err;
+
        return kszphy_config_init(phydev);
 }
 
@@ -5691,6 +5748,8 @@ static struct phy_driver ksphy_driver[] = {
        /* PHY_GBIT_FEATURES */
        .config_init    = ksz9477_config_init,
        .config_intr    = kszphy_config_intr,
+       .config_aneg    = ksz9477_config_aneg,
+       .read_status    = ksz9477_read_status,
        .handle_interrupt = kszphy_handle_interrupt,
        .suspend        = genphy_suspend,
        .resume         = ksz9477_resume,