common: miiphyutil: Add helper function for mdio bus name

The most of ethernet drivers are using this mdio registration sequence.
strcpy(priv->bus->name, "emac");
mdio_register(priv->bus);
Where driver can be used only with one MDIO bus because only unique
name should be used.

Other drivers are using unique device name for MDIO registration to
support multiple instances.
snprintf(priv->bus->name, sizeof(bus->name), "%s", name);

With DM dev->seq is used more even in logs
(like random MAC address generation:
printf("\nWarning: %s (eth%d) using random MAC address - %pM\n",
       dev->name, dev->seq, pdata->enetaddr);
)
where eth%d prefix is used.

Simplify driver code to register mdio device with dev->seq number
to simplify mdio registration and reduce code duplication across
all drivers. With DM_SEQ_ALIAS enabled dev->seq reflects alias setting.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

common/miiphyutil.c

@@ -107,6 +107,18 @@ int mdio_register(struct mii_dev *bus)
 	return 0;
 }
 
+int mdio_register_seq(struct mii_dev *bus, int seq)
+{
+	int ret;
+
+	/* Setup a unique name for each mdio bus */
+	ret = snprintf(bus->name, MDIO_NAME_LEN, "eth%d", seq);
+	if (ret < 0)
+		return ret;
+
+	return mdio_register(bus);
+}
+
 int mdio_unregister(struct mii_dev *bus)
 {
 	if (!bus)

include/miiphy.h

@@ -48,6 +48,15 @@ void miiphy_listdev(void);
 struct mii_dev *mdio_alloc(void);
 void mdio_free(struct mii_dev *bus);
 int mdio_register(struct mii_dev *bus);
+
+/**
+ * mdio_register_seq - Register mdio bus with sequence number
+ * @bus: mii device structure
+ * @seq: sequence number
+ *
+ * Return: 0 if success, negative value if error
+ */
+int mdio_register_seq(struct mii_dev *bus, int seq);
 int mdio_unregister(struct mii_dev *bus);
 void mdio_list_devices(void);