Re: [PATCH 2/2] net: mdio: Add BCM6368 MDIO mux bus controller

+static int bcm6368_mdiomux_probe(struct platform_device *pdev)
+{
+	struct bcm6368_mdiomux_desc *md;
+	struct mii_bus *bus;
+	struct resource *res;
+	int rc;
+
+	md = devm_kzalloc(&pdev->dev, sizeof(*md), GFP_KERNEL);
+	if (!md)
+		return -ENOMEM;
+	md->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+
+	/* Just ioremap, as this MDIO block is usually integrated into an
+	 * Ethernet MAC controller register range
+	 */
+	md->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+	if (!md->base) {
+		dev_err(&pdev->dev, "failed to ioremap register\n");
+		return -ENOMEM;
+	}
+
+	md->mii_bus = devm_mdiobus_alloc(&pdev->dev);
+	if (!md->mii_bus) {
+		dev_err(&pdev->dev, "mdiomux bus alloc failed\n");
+		return ENOMEM;
+	}
+
+	bus = md->mii_bus;
+	bus->priv = md;
+	bus->name = "BCM6368 MDIO mux bus";
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
+	bus->parent = &pdev->dev;
+	bus->read = bcm6368_mdiomux_read;
+	bus->write = bcm6368_mdiomux_write;
+	bus->phy_mask = 0x3f;
+	bus->dev.of_node = pdev->dev.of_node;
+
+	rc = mdiobus_register(bus);
+	if (rc) {
+		dev_err(&pdev->dev, "mdiomux registration failed\n");
+		return rc;
+	}

So this is different to all the other mux drivers. Normally there is
an MDIO driver. And there is a mux driver. Two separate drivers. The
mux driver uses a phandle to reference the MDIO driver. Here we have
both in one driver.

Does this MDIO bus device exist as a standalone device? Without the
mux? If silicon does exist like that, having two separate drivers
would be better.

     Andrew