[PATCH 2/2] net: ks8851: Register MDIO bus and the internal PHY

[Marek Vasut <marex@denx.de>]

The KS8851 has a reduced internal PHY, which is accessible through its
registers at offset 0xe4. The PHY is compatible with KS886x PHY present
in Micrel switches, except the PHY ID Low/High registers are swapped.
Register MDIO bus so this PHY can be detected and probed by phylib.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Lukas Wunner <lukas@wunner.de>
To: netdev@vger.kernel.org
---
 drivers/net/ethernet/micrel/ks8851.h        |  1 +
 drivers/net/ethernet/micrel/ks8851_common.c | 69 ++++++++++++++++++++-
 2 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/micrel/ks8851.h b/drivers/net/ethernet/micrel/ks8851.h
index 2b319e451121..9bed9e024d81 100644
--- a/drivers/net/ethernet/micrel/ks8851.h
+++ b/drivers/net/ethernet/micrel/ks8851.h
@@ -403,6 +403,7 @@ struct ks8851_net {
 	struct regulator	*vdd_reg;
 	struct regulator	*vdd_io;
 	int			gpio;
+	struct mii_bus		*mii_bus;
 
 	void			(*lock)(struct ks8851_net *ks,
 					unsigned long *flags);
diff --git a/drivers/net/ethernet/micrel/ks8851_common.c b/drivers/net/ethernet/micrel/ks8851_common.c
index 6fc7483aea03..c4f5cb9768ef 100644
--- a/drivers/net/ethernet/micrel/ks8851_common.c
+++ b/drivers/net/ethernet/micrel/ks8851_common.c
@@ -23,6 +23,7 @@
 
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
+#include <linux/of_mdio.h>
 #include <linux/of_net.h>
 
 #include "ks8851.h"
@@ -983,6 +984,24 @@ static void ks8851_phy_write(struct net_device *dev,
 	}
 }
 
+static int ks8851_mdio_read(struct mii_bus *bus, int phy_id, int reg)
+{
+	struct ks8851_net *ks = bus->priv;
+
+	if (phy_id != 0)
+		return 0xffffffff;
+
+	return ks8851_phy_read(ks->netdev, phy_id, reg);
+}
+
+static int ks8851_mdio_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
+{
+	struct ks8851_net *ks = bus->priv;
+
+	ks8851_phy_write(ks->netdev, phy_id, reg, val);
+	return 0;
+}
+
 /**
  * ks8851_read_selftest - read the selftest memory info.
  * @ks: The device state
@@ -1046,6 +1065,42 @@ int ks8851_resume(struct device *dev)
 }
 #endif
 
+static int ks8851_register_mdiobus(struct ks8851_net *ks, struct device *dev)
+{
+	struct mii_bus *mii_bus;
+	int ret;
+
+	mii_bus = mdiobus_alloc();
+	if (!mii_bus)
+		return -ENOMEM;
+
+	mii_bus->name = "ks8851_eth_mii";
+	mii_bus->read = ks8851_mdio_read;
+	mii_bus->write = ks8851_mdio_write;
+	mii_bus->priv = ks;
+	mii_bus->parent = dev;
+	mii_bus->phy_mask = ~BIT(0);
+	snprintf(mii_bus->id, MII_BUS_ID_SIZE, "%s", dev_name(dev));
+
+	ret = mdiobus_register(mii_bus);
+	if (ret)
+		goto err_mdiobus_register;
+
+	ks->mii_bus = mii_bus;
+
+	return 0;
+
+err_mdiobus_register:
+	mdiobus_free(mii_bus);
+	return ret;
+}
+
+static void ks8851_unregister_mdiobus(struct ks8851_net *ks)
+{
+	mdiobus_unregister(ks->mii_bus);
+	mdiobus_free(ks->mii_bus);
+}
+
 int ks8851_probe_common(struct net_device *netdev, struct device *dev,
 			int msg_en)
 {
@@ -1104,6 +1159,8 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev,
 
 	INIT_WORK(&ks->rxctrl_work, ks8851_rxctrl_work);
 
+	SET_NETDEV_DEV(netdev, dev);
+
 	/* setup EEPROM state */
 	ks->eeprom.data = ks;
 	ks->eeprom.width = PCI_EEPROM_WIDTH_93C46;
@@ -1120,6 +1177,10 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev,
 
 	dev_info(dev, "message enable is %d\n", msg_en);
 
+	ret = ks8851_register_mdiobus(ks, dev);
+	if (ret)
+		goto err_mdio;
+
 	/* set the default message enable */
 	ks->msg_enable = netif_msg_init(msg_en, NETIF_MSG_DRV |
 						NETIF_MSG_PROBE |
@@ -1128,7 +1189,6 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev,
 	skb_queue_head_init(&ks->txq);
 
 	netdev->ethtool_ops = &ks8851_ethtool_ops;
-	SET_NETDEV_DEV(netdev, dev);
 
 	dev_set_drvdata(dev, ks);
 
@@ -1156,7 +1216,7 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev,
 	ret = register_netdev(netdev);
 	if (ret) {
 		dev_err(dev, "failed to register network device\n");
-		goto err_netdev;
+		goto err_id;
 	}
 
 	netdev_info(netdev, "revision %d, MAC %pM, IRQ %d, %s EEPROM\n",
@@ -1165,8 +1225,9 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev,
 
 	return 0;
 
-err_netdev:
 err_id:
+	ks8851_unregister_mdiobus(ks);
+err_mdio:
 	if (gpio_is_valid(gpio))
 		gpio_set_value(gpio, 0);
 	regulator_disable(ks->vdd_reg);
@@ -1180,6 +1241,8 @@ int ks8851_remove_common(struct device *dev)
 {
 	struct ks8851_net *priv = dev_get_drvdata(dev);
 
+	ks8851_unregister_mdiobus(priv);
+
 	if (netif_msg_drv(priv))
 		dev_info(dev, "remove\n");
 
-- 
2.29.2