mdio: Add support for mdio drivers.

Not all devices on an MDIO bus are PHYs. Meaning not all MDIO drivers
are PHY drivers. Add support for generic MDIO drivers.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/mdio_device.c

@@ -0,0 +1,169 @@
+/* Framework for MDIO devices, other than PHYs.
+ *
+ * Copyright (c) 2016 Andrew Lunn <andrew@lunn.ch>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mdio.h>
+#include <linux/mii.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/unistd.h>
+
+void mdio_device_free(struct mdio_device *mdiodev)
+{
+	put_device(&mdiodev->dev);
+}
+EXPORT_SYMBOL(mdio_device_free);
+
+static void mdio_device_release(struct device *dev)
+{
+	kfree(to_mdio_device(dev));
+}
+
+struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr)
+{
+	struct mdio_device *mdiodev;
+
+	/* We allocate the device, and initialize the default values */
+	mdiodev = kzalloc(sizeof(*mdiodev), GFP_KERNEL);
+	if (!mdiodev)
+		return ERR_PTR(-ENOMEM);
+
+	mdiodev->dev.release = mdio_device_release;
+	mdiodev->dev.parent = &bus->dev;
+	mdiodev->dev.bus = &mdio_bus_type;
+	mdiodev->bus = bus;
+	mdiodev->addr = addr;
+
+	dev_set_name(&mdiodev->dev, PHY_ID_FMT, bus->id, addr);
+
+	device_initialize(&mdiodev->dev);
+
+	return mdiodev;
+}
+EXPORT_SYMBOL(mdio_device_create);
+
+/**
+ * mdio_device_register - Register the mdio device on the MDIO bus
+ * @mdiodev: mdio_device structure to be added to the MDIO bus
+ */
+int mdio_device_register(struct mdio_device *mdiodev)
+{
+	int err;
+
+	dev_info(&mdiodev->dev, "mdio_device_register\n");
+
+	err = mdiobus_register_device(mdiodev);
+	if (err)
+		return err;
+
+	err = device_add(&mdiodev->dev);
+	if (err) {
+		pr_err("MDIO %d failed to add\n", mdiodev->addr);
+		goto out;
+	}
+
+	return 0;
+
+ out:
+	mdiobus_unregister_device(mdiodev);
+	return err;
+}
+EXPORT_SYMBOL(mdio_device_register);
+
+/**
+ * mdio_device_remove - Remove a previously registered mdio device from the
+ *			MDIO bus
+ * @mdiodev: mdio_device structure to remove
+ *
+ * This doesn't free the mdio_device itself, it merely reverses the effects
+ * of mdio_device_register(). Use mdio_device_free() to free the device
+ * after calling this function.
+ */
+void mdio_device_remove(struct mdio_device *mdiodev)
+{
+	device_del(&mdiodev->dev);
+	mdiobus_unregister_device(mdiodev);
+}
+EXPORT_SYMBOL(mdio_device_remove);
+
+/**
+ * mdio_probe - probe an MDIO device
+ * @dev: device to probe
+ *
+ * Description: Take care of setting up the mdio_device structure
+ * and calling the driver to probe the device.
+ */
+static int mdio_probe(struct device *dev)
+{
+	struct mdio_device *mdiodev = to_mdio_device(dev);
+	struct device_driver *drv = mdiodev->dev.driver;
+	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
+	int err = 0;
+
+	if (mdiodrv->probe)
+		err = mdiodrv->probe(mdiodev);
+
+	return err;
+}
+
+static int mdio_remove(struct device *dev)
+{
+	struct mdio_device *mdiodev = to_mdio_device(dev);
+	struct device_driver *drv = mdiodev->dev.driver;
+	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
+
+	if (mdiodrv->remove)
+		mdiodrv->remove(mdiodev);
+
+	return 0;
+}
+
+/**
+ * mdio_driver_register - register an mdio_driver with the MDIO layer
+ * @new_driver: new mdio_driver to register
+ */
+int mdio_driver_register(struct mdio_driver *drv)
+{
+	struct mdio_driver_common *mdiodrv = &drv->mdiodrv;
+	int retval;
+
+	pr_info("mdio_driver_register: %s\n", mdiodrv->driver.name);
+
+	mdiodrv->driver.bus = &mdio_bus_type;
+	mdiodrv->driver.probe = mdio_probe;
+	mdiodrv->driver.remove = mdio_remove;
+
+	retval = driver_register(&mdiodrv->driver);
+	if (retval) {
+		pr_err("%s: Error %d in registering driver\n",
+		       mdiodrv->driver.name, retval);
+
+		return retval;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(mdio_driver_register);
+
+void mdio_driver_unregister(struct mdio_driver *drv)
+{
+	struct mdio_driver_common *mdiodrv = &drv->mdiodrv;
+
+	driver_unregister(&mdiodrv->driver);
+}
+EXPORT_SYMBOL(mdio_driver_unregister);