[PATCH 4/6] net: fec: add support for DM_MDIO

[Tim Harvey <tharvey@gateworks.com>]

Add support for DM_MDIO by registering a UCLASS_MDIO driver and
attempting to use it. This is necessary if wanting to use a DSA
driver for example hanging off of the FEC MAC.

Care is taken to fallback to non DM_MDIO as several boards define
DM_MDIO without having the proper device-tree configuration necessary
such as an mdio subnode, a phy-mode prop, and either a valid phy-handle
prop or fixed-phy subnode.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
---
 drivers/net/fec_mxc.c | 113 ++++++++++++++++++++++++++++++++++++++----
 drivers/net/fec_mxc.h |   1 +
 2 files changed, 104 insertions(+), 10 deletions(-)

diff --git a/drivers/net/fec_mxc.c b/drivers/net/fec_mxc.c
index e8ebef09032a..374ef9d67d5e 100644
--- a/drivers/net/fec_mxc.c
+++ b/drivers/net/fec_mxc.c
@@ -30,6 +30,8 @@
 #include <asm/arch/imx-regs.h>
 #include <asm/mach-imx/sys_proto.h>
 #include <asm-generic/gpio.h>
+#include <dm/device_compat.h>
+#include <dm/lists.h>
 
 #include "fec_mxc.h"
 #include <eth_phy.h>
@@ -1025,6 +1027,80 @@ struct mii_dev *fec_get_miibus(ulong base_addr, int dev_id)
 	return bus;
 }
 
+#ifdef CONFIG_DM_MDIO
+struct dm_fec_mdio_priv {
+	struct ethernet_regs *regs;
+};
+
+static int dm_fec_mdio_read(struct udevice *dev, int addr, int devad, int reg)
+{
+	struct dm_fec_mdio_priv *priv = dev_get_priv(dev);
+
+	return fec_mdio_read(priv->regs, addr, reg);
+}
+
+static int dm_fec_mdio_write(struct udevice *dev, int addr, int devad, int reg, u16 data)
+{
+	struct dm_fec_mdio_priv *priv = dev_get_priv(dev);
+
+	return fec_mdio_write(priv->regs, addr, reg, data);
+}
+
+static const struct mdio_ops dm_fec_mdio_ops = {
+	.read = dm_fec_mdio_read,
+	.write = dm_fec_mdio_write,
+};
+
+static int dm_fec_mdio_probe(struct udevice *dev)
+{
+	struct dm_fec_mdio_priv *priv = dev_get_priv(dev);
+
+	priv->regs = (struct ethernet_regs *)ofnode_get_addr(dev_ofnode(dev->parent));
+
+	return 0;
+}
+
+U_BOOT_DRIVER(fec_mdio) = {
+	.name		= "fec_mdio",
+	.id		= UCLASS_MDIO,
+	.probe		= dm_fec_mdio_probe,
+	.ops		= &dm_fec_mdio_ops,
+	.priv_auto	= sizeof(struct dm_fec_mdio_priv),
+};
+
+static int dm_fec_bind_mdio(struct udevice *dev)
+{
+	struct udevice *mdiodev;
+	const char *name;
+	ofnode mdio;
+	int ret;
+
+	/* for a UCLASS_MDIO driver we need to bind and probe manually
+	 * for an internal MDIO bus that has no dt compatible of its own
+	 */
+	ofnode_for_each_subnode(mdio, dev_ofnode(dev)) {
+		name = ofnode_get_name(mdio);
+
+		if (strcmp(name, "mdio"))
+			continue;
+
+		ret = device_bind_driver_to_node(dev, "fec_mdio",
+						 name, mdio, &mdiodev);
+		if (ret)
+			return ret;
+
+		/* need to probe it as there is no compatible to do so */
+		ret = uclass_get_device_by_ofnode(UCLASS_MDIO, mdio, &mdiodev);
+		if (!ret)
+			return 0;
+
+		break;
+	}
+
+	return ret;
+}
+#endif
+
 static int fecmxc_read_rom_hwaddr(struct udevice *dev)
 {
 	struct fec_priv *priv = dev_get_priv(dev);
@@ -1088,7 +1164,7 @@ static int device_get_phy_addr(struct fec_priv *priv, struct udevice *dev)
 
 static int fec_phy_init(struct fec_priv *priv, struct udevice *dev)
 {
-	struct phy_device *phydev;
+	struct phy_device *phydev = NULL;
 	int addr;
 
 	addr = device_get_phy_addr(priv, dev);
@@ -1096,7 +1172,12 @@ static int fec_phy_init(struct fec_priv *priv, struct udevice *dev)
 	addr = CONFIG_FEC_MXC_PHYADDR;
 #endif
 
-	phydev = phy_connect(priv->bus, addr, dev, priv->interface);
+#ifdef CONFIG_DM_MDIO
+	if (priv->dm_mdio)
+		phydev = dm_eth_phy_connect(dev);
+#endif
+	if (!phydev)
+		phydev = phy_connect(priv->bus, addr, dev, priv->interface);
 	if (!phydev)
 		return -ENODEV;
 
@@ -1227,11 +1308,19 @@ static int fecmxc_probe(struct udevice *dev)
 
 	priv->dev_id = dev_seq(dev);
 
+#ifdef CONFIG_DM_MDIO
+	ret = dm_fec_bind_mdio(dev);
+	if (!ret) {
+		ret = fec_phy_init(priv, dev);
+		if (!ret)
+			priv->dm_mdio = true;
+	}
+#endif
 #ifdef CONFIG_DM_ETH_PHY
 	bus = eth_phy_get_mdio_bus(dev);
 #endif
 
-	if (!bus) {
+	if (!bus && !priv->dm_mdio) {
 		dm_mii_bus = false;
 #ifdef CONFIG_FEC_MXC_MDIO_BASE
 		bus = fec_get_miibus((ulong)CONFIG_FEC_MXC_MDIO_BASE,
@@ -1240,7 +1329,7 @@ static int fecmxc_probe(struct udevice *dev)
 		bus = fec_get_miibus((ulong)priv->eth, dev_seq(dev));
 #endif
 	}
-	if (!bus) {
+	if (!bus && !priv->dm_mdio) {
 		ret = -ENOMEM;
 		goto err_mii;
 	}
@@ -1271,14 +1360,16 @@ static int fecmxc_probe(struct udevice *dev)
 		break;
 	}
 
-	ret = fec_phy_init(priv, dev);
-	if (ret)
-		goto err_phy;
+	if (!priv->dm_mdio) {
+		ret = fec_phy_init(priv, dev);
+		if (ret)
+			goto err_phy;
+	}
 
 	return 0;
 
 err_phy:
-	if (!dm_mii_bus) {
+	if (!dm_mii_bus && !priv->dm_mdio) {
 		mdio_unregister(bus);
 		free(bus);
 	}
@@ -1294,8 +1385,10 @@ static int fecmxc_remove(struct udevice *dev)
 
 	free(priv->phydev);
 	fec_free_descs(priv);
-	mdio_unregister(priv->bus);
-	mdio_free(priv->bus);
+	if (priv->bus) {
+		mdio_unregister(priv->bus);
+		mdio_free(priv->bus);
+	}
 
 #ifdef CONFIG_DM_REGULATOR
 	if (priv->phy_supply)
diff --git a/drivers/net/fec_mxc.h b/drivers/net/fec_mxc.h
index 48faa33d66ec..c297880ccc54 100644
--- a/drivers/net/fec_mxc.h
+++ b/drivers/net/fec_mxc.h
@@ -248,6 +248,7 @@ struct fec_priv {
 	uint8_t *tdb_ptr;
 	int dev_id;
 	struct mii_dev *bus;
+	bool dm_mdio;
 #ifdef CONFIG_PHYLIB
 	struct phy_device *phydev;
 	ofnode phy_of_node;
-- 
2.17.1