net: phy: microchip: lan937x: add support for 100BaseTX PHY

Add support of 100BaseTX PHY build in to LAN9371 and LAN9372 switches.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Link: https://patch.msgid.link/20240706154201.1456098-1-o.rempel@pengutronix.deSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/phy/microchip.c

@@ -12,8 +12,14 @@
 #include <linux/of.h>
 #include <dt-bindings/net/microchip-lan78xx.h>
 
+#define PHY_ID_LAN937X_TX			0x0007c190
+
+#define LAN937X_MODE_CTRL_STATUS_REG		0x11
+#define LAN937X_AUTOMDIX_EN			BIT(7)
+#define LAN937X_MDI_MODE			BIT(6)
+
 #define DRIVER_AUTHOR	"WOOJUNG HUH <woojung.huh@microchip.com>"
-#define DRIVER_DESC	"Microchip LAN88XX PHY driver"
+#define DRIVER_DESC	"Microchip LAN88XX/LAN937X TX PHY driver"
 
 struct lan88xx_priv {
 	int	chip_id;
@@ -373,6 +379,115 @@ static void lan88xx_link_change_notify(struct phy_device *phydev)
 	}
 }
 
+/**
+ * lan937x_tx_read_mdix_status - Read the MDIX status for the LAN937x TX PHY.
+ * @phydev: Pointer to the phy_device structure.
+ *
+ * This function reads the MDIX status of the LAN937x TX PHY and sets the
+ * mdix_ctrl and mdix fields of the phy_device structure accordingly.
+ * Note that MDIX status is not supported in AUTO mode, and will be set
+ * to invalid in such cases.
+ *
+ * Return: 0 on success, a negative error code on failure.
+ */
+static int lan937x_tx_read_mdix_status(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = phy_read(phydev, LAN937X_MODE_CTRL_STATUS_REG);
+	if (ret < 0)
+		return ret;
+
+	if (ret & LAN937X_AUTOMDIX_EN) {
+		phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
+		/* MDI/MDIX status is unknown */
+		phydev->mdix = ETH_TP_MDI_INVALID;
+	} else if (ret & LAN937X_MDI_MODE) {
+		phydev->mdix_ctrl = ETH_TP_MDI_X;
+		phydev->mdix = ETH_TP_MDI_X;
+	} else {
+		phydev->mdix_ctrl = ETH_TP_MDI;
+		phydev->mdix = ETH_TP_MDI;
+	}
+
+	return 0;
+}
+
+/**
+ * lan937x_tx_read_status - Read the status for the LAN937x TX PHY.
+ * @phydev: Pointer to the phy_device structure.
+ *
+ * This function reads the status of the LAN937x TX PHY and updates the
+ * phy_device structure accordingly.
+ *
+ * Return: 0 on success, a negative error code on failure.
+ */
+static int lan937x_tx_read_status(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = genphy_read_status(phydev);
+	if (ret < 0)
+		return ret;
+
+	return lan937x_tx_read_mdix_status(phydev);
+}
+
+/**
+ * lan937x_tx_set_mdix - Set the MDIX mode for the LAN937x TX PHY.
+ * @phydev: Pointer to the phy_device structure.
+ *
+ * This function configures the MDIX mode of the LAN937x TX PHY based on the
+ * mdix_ctrl field of the phy_device structure. The MDIX mode can be set to
+ * MDI (straight-through), MDIX (crossover), or AUTO (auto-MDIX). If the mode
+ * is not recognized, it returns 0 without making any changes.
+ *
+ * Return: 0 on success, a negative error code on failure.
+ */
+static int lan937x_tx_set_mdix(struct phy_device *phydev)
+{
+	u16 val;
+
+	switch (phydev->mdix_ctrl) {
+	case ETH_TP_MDI:
+		val = 0;
+		break;
+	case ETH_TP_MDI_X:
+		val = LAN937X_MDI_MODE;
+		break;
+	case ETH_TP_MDI_AUTO:
+		val = LAN937X_AUTOMDIX_EN;
+		break;
+	default:
+		return 0;
+	}
+
+	return phy_modify(phydev, LAN937X_MODE_CTRL_STATUS_REG,
+			  LAN937X_AUTOMDIX_EN | LAN937X_MDI_MODE, val);
+}
+
+/**
+ * lan937x_tx_config_aneg - Configure auto-negotiation and fixed modes for the
+ *                          LAN937x TX PHY.
+ * @phydev: Pointer to the phy_device structure.
+ *
+ * This function configures the MDIX mode for the LAN937x TX PHY and then
+ * proceeds to configure the auto-negotiation or fixed mode settings
+ * based on the phy_device structure.
+ *
+ * Return: 0 on success, a negative error code on failure.
+ */
+static int lan937x_tx_config_aneg(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = lan937x_tx_set_mdix(phydev);
+	if (ret < 0)
+		return ret;
+
+	return genphy_config_aneg(phydev);
+}
+
 static struct phy_driver microchip_phy_driver[] = {
 {
 	.phy_id		= 0x0007c132,
@@ -400,12 +515,21 @@ static struct phy_driver microchip_phy_driver[] = {
 	.set_wol	= lan88xx_set_wol,
 	.read_page	= lan88xx_read_page,
 	.write_page	= lan88xx_write_page,
+},
+{
+	PHY_ID_MATCH_MODEL(PHY_ID_LAN937X_TX),
+	.name		= "Microchip LAN937x TX",
+	.suspend	= genphy_suspend,
+	.resume		= genphy_resume,
+	.config_aneg	= lan937x_tx_config_aneg,
+	.read_status	= lan937x_tx_read_status,
 } };
 
 module_phy_driver(microchip_phy_driver);
 
 static struct mdio_device_id __maybe_unused microchip_tbl[] = {
 	{ 0x0007c132, 0xfffffff2 },
+	{ PHY_ID_MATCH_MODEL(PHY_ID_LAN937X_TX) },
 	{ }
 };