/*
 * OF helpers for the MDIO (Ethernet PHY) API
 *
 * Copyright (c) 2009 Secret Lab Technologies, Ltd.
 *
 * This file is released under the GPLv2
 *
 * This file provides helper functions for extracting PHY device information
 * out of the OpenFirmware device tree and using it to populate an mii_bus.
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/netdevice.h>
#include <linux/err.h>
#include <linux/phy.h>
#include <linux/phy_fixed.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/of_irq.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include <linux/module.h>

#define DEFAULT_GPIO_RESET_DELAY	10	/* in microseconds */

MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
MODULE_LICENSE("GPL");

/* Extract the clause 22 phy ID from the compatible string of the form
 * ethernet-phy-idAAAA.BBBB */
static int of_get_phy_id(struct device_node *device, u32 *phy_id)
{
	struct property *prop;
	const char *cp;
	unsigned int upper, lower;

	of_property_for_each_string(device, "compatible", prop, cp) {
		if (sscanf(cp, "ethernet-phy-id%4x.%4x", &upper, &lower) == 2) {
			*phy_id = ((upper & 0xFFFF) << 16) | (lower & 0xFFFF);
			return 0;
		}
	}
	return -EINVAL;
}

static int of_mdiobus_register_phy(struct mii_bus *mdio,
				    struct device_node *child, u32 addr)
{
	struct phy_device *phy;
	bool is_c45;
	int rc;
	u32 phy_id;

	is_c45 = of_device_is_compatible(child,
					 "ethernet-phy-ieee802.3-c45");

	if (!is_c45 && !of_get_phy_id(child, &phy_id))
		phy = phy_device_create(mdio, addr, phy_id, 0, NULL);
	else
		phy = get_phy_device(mdio, addr, is_c45);
	if (IS_ERR(phy))
		return PTR_ERR(phy);

	rc = of_irq_get(child, 0);
	if (rc == -EPROBE_DEFER) {
		phy_device_free(phy);
		return rc;
	}
	if (rc > 0) {
		phy->irq = rc;
		mdio->irq[addr] = rc;
	} else {
		phy->irq = mdio->irq[addr];
	}

	if (of_property_read_bool(child, "broken-turn-around"))
		mdio->phy_ignore_ta_mask |= 1 << addr;

	/* Associate the OF node with the device structure so it
	 * can be looked up later */
	of_node_get(child);
	phy->mdio.dev.of_node = child;

	/* All data is now stored in the phy struct;
	 * register it */
	rc = phy_device_register(phy);
	if (rc) {
		phy_device_free(phy);
		of_node_put(child);
		return rc;
	}

	dev_dbg(&mdio->dev, "registered phy %s at address %i\n",
		child->name, addr);
	return 0;
}

static int of_mdiobus_register_device(struct mii_bus *mdio,
				      struct device_node *child, u32 addr)
{
	struct mdio_device *mdiodev;
	int rc;

	mdiodev = mdio_device_create(mdio, addr);
	if (IS_ERR(mdiodev))
		return PTR_ERR(mdiodev);

	/* Associate the OF node with the device structure so it
	 * can be looked up later.
	 */
	of_node_get(child);
	mdiodev->dev.of_node = child;

	/* All data is now stored in the mdiodev struct; register it. */
	rc = mdio_device_register(mdiodev);
	if (rc) {
		mdio_device_free(mdiodev);
		of_node_put(child);
		return rc;
	}

	dev_dbg(&mdio->dev, "registered mdio device %s at address %i\n",
		child->name, addr);
	return 0;
}

/* The following is a list of PHY compatible strings which appear in
 * some DTBs. The compatible string is never matched against a PHY
 * driver, so is pointless. We only expect devices which are not PHYs
 * to have a compatible string, so they can be matched to an MDIO
 * driver.  Encourage users to upgrade their DT blobs to remove these.
 */
static const struct of_device_id whitelist_phys[] = {
	{ .compatible = "brcm,40nm-ephy" },
	{ .compatible = "broadcom,bcm5241" },
	{ .compatible = "marvell,88E1111", },
	{ .compatible = "marvell,88e1116", },
	{ .compatible = "marvell,88e1118", },
	{ .compatible = "marvell,88e1145", },
	{ .compatible = "marvell,88e1149r", },
	{ .compatible = "marvell,88e1310", },
	{ .compatible = "marvell,88E1510", },
	{ .compatible = "marvell,88E1514", },
	{ .compatible = "moxa,moxart-rtl8201cp", },
	{}
};

/*
 * Return true if the child node is for a phy. It must either:
 * o Compatible string of "ethernet-phy-idX.X"
 * o Compatible string of "ethernet-phy-ieee802.3-c45"
 * o Compatible string of "ethernet-phy-ieee802.3-c22"
 * o In the white list above (and issue a warning)
 * o No compatibility string
 *
 * A device which is not a phy is expected to have a compatible string
 * indicating what sort of device it is.
 */
static bool of_mdiobus_child_is_phy(struct device_node *child)
{
	u32 phy_id;

	if (of_get_phy_id(child, &phy_id) != -EINVAL)
		return true;

	if (of_device_is_compatible(child, "ethernet-phy-ieee802.3-c45"))
		return true;

	if (of_device_is_compatible(child, "ethernet-phy-ieee802.3-c22"))
		return true;

	if (of_match_node(whitelist_phys, child)) {
		pr_warn(FW_WARN
			"%pOF: Whitelisted compatible string. Please remove\n",
			child);
		return true;
	}

	if (!of_find_property(child, "compatible", NULL))
		return true;

	return false;
}

/**
 * of_mdiobus_register - Register mii_bus and create PHYs from the device tree
 * @mdio: pointer to mii_bus structure
 * @np: pointer to device_node of MDIO bus.
 *
 * This function registers the mii_bus structure and registers a phy_device
 * for each child node of @np.
 */
int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
{
	struct device_node *child;
	bool scanphys = false;
	int addr, rc;

	/* Do not continue if the node is disabled */
	if (!of_device_is_available(np))
		return -ENODEV;

	/* Mask out all PHYs from auto probing.  Instead the PHYs listed in
	 * the device tree are populated after the bus has been registered */
	mdio->phy_mask = ~0;

	mdio->dev.of_node = np;

	/* Get bus level PHY reset GPIO details */
	mdio->reset_delay_us = DEFAULT_GPIO_RESET_DELAY;
	of_property_read_u32(np, "reset-delay-us", &mdio->reset_delay_us);

	/* Register the MDIO bus */
	rc = mdiobus_register(mdio);
	if (rc)
		return rc;

	/* Loop over the child nodes and register a phy_device for each phy */
	for_each_available_child_of_node(np, child) {
		addr = of_mdio_parse_addr(&mdio->dev, child);
		if (addr < 0) {
			scanphys = true;
			continue;
		}

		if (of_mdiobus_child_is_phy(child))
			rc = of_mdiobus_register_phy(mdio, child, addr);
		else
			rc = of_mdiobus_register_device(mdio, child, addr);

		if (rc == -ENODEV)
			dev_err(&mdio->dev,
				"MDIO device at address %d is missing.\n",
				addr);
		else if (rc)
			goto unregister;
	}

	if (!scanphys)
		return 0;

	/* auto scan for PHYs with empty reg property */
	for_each_available_child_of_node(np, child) {
		/* Skip PHYs with reg property set */
		if (of_find_property(child, "reg", NULL))
			continue;

		for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
			/* skip already registered PHYs */
			if (mdiobus_is_registered_device(mdio, addr))
				continue;

			/* be noisy to encourage people to set reg property */
			dev_info(&mdio->dev, "scan phy %s at address %i\n",
				 child->name, addr);

			if (of_mdiobus_child_is_phy(child)) {
				/* -ENODEV is the return code that PHYLIB has
				 * standardized on to indicate that bus
				 * scanning should continue.
				 */
				rc = of_mdiobus_register_phy(mdio, child, addr);
				if (!rc)
					break;
				if (rc != -ENODEV)
					goto unregister;
			}
		}
	}

	return 0;

unregister:
	of_node_put(child);
	mdiobus_unregister(mdio);
	return rc;
}
EXPORT_SYMBOL(of_mdiobus_register);

/* Helper function for of_phy_find_device */
static int of_phy_match(struct device *dev, void *phy_np)
{
	return dev->of_node == phy_np;
}

/**
 * of_phy_find_device - Give a PHY node, find the phy_device
 * @phy_np: Pointer to the phy's device tree node
 *
 * If successful, returns a pointer to the phy_device with the embedded
 * struct device refcount incremented by one, or NULL on failure.
 */
struct phy_device *of_phy_find_device(struct device_node *phy_np)
{
	struct device *d;
	struct mdio_device *mdiodev;

	if (!phy_np)
		return NULL;

	d = bus_find_device(&mdio_bus_type, NULL, phy_np, of_phy_match);
	if (d) {
		mdiodev = to_mdio_device(d);
		if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY)
			return to_phy_device(d);
		put_device(d);
	}

	return NULL;
}
EXPORT_SYMBOL(of_phy_find_device);

/**
 * of_phy_connect - Connect to the phy described in the device tree
 * @dev: pointer to net_device claiming the phy
 * @phy_np: Pointer to device tree node for the PHY
 * @hndlr: Link state callback for the network device
 * @flags: flags to pass to the PHY
 * @iface: PHY data interface type
 *
 * If successful, returns a pointer to the phy_device with the embedded
 * struct device refcount incremented by one, or NULL on failure. The
 * refcount must be dropped by calling phy_disconnect() or phy_detach().
 */
struct phy_device *of_phy_connect(struct net_device *dev,
				  struct device_node *phy_np,
				  void (*hndlr)(struct net_device *), u32 flags,
				  phy_interface_t iface)
{
	struct phy_device *phy = of_phy_find_device(phy_np);
	int ret;

	if (!phy)
		return NULL;

	phy->dev_flags = flags;

	ret = phy_connect_direct(dev, phy, hndlr, iface);

	/* refcount is held by phy_connect_direct() on success */
	put_device(&phy->mdio.dev);

	return ret ? NULL : phy;
}
EXPORT_SYMBOL(of_phy_connect);

/**
 * of_phy_get_and_connect
 * - Get phy node and connect to the phy described in the device tree
 * @dev: pointer to net_device claiming the phy
 * @np: Pointer to device tree node for the net_device claiming the phy
 * @hndlr: Link state callback for the network device
 *
 * If successful, returns a pointer to the phy_device with the embedded
 * struct device refcount incremented by one, or NULL on failure. The
 * refcount must be dropped by calling phy_disconnect() or phy_detach().
 */
struct phy_device *of_phy_get_and_connect(struct net_device *dev,
					  struct device_node *np,
					  void (*hndlr)(struct net_device *))
{
	phy_interface_t iface;
	struct device_node *phy_np;
	struct phy_device *phy;

	iface = of_get_phy_mode(np);
	if ((int)iface < 0)
		return NULL;

	phy_np = of_parse_phandle(np, "phy-handle", 0);
	if (!phy_np)
		return NULL;

	phy = of_phy_connect(dev, phy_np, hndlr, 0, iface);

	of_node_put(phy_np);

	return phy;
}
EXPORT_SYMBOL(of_phy_get_and_connect);

/**
 * of_phy_attach - Attach to a PHY without starting the state machine
 * @dev: pointer to net_device claiming the phy
 * @phy_np: Node pointer for the PHY
 * @flags: flags to pass to the PHY
 * @iface: PHY data interface type
 *
 * If successful, returns a pointer to the phy_device with the embedded
 * struct device refcount incremented by one, or NULL on failure. The
 * refcount must be dropped by calling phy_disconnect() or phy_detach().
 */
struct phy_device *of_phy_attach(struct net_device *dev,
				 struct device_node *phy_np, u32 flags,
				 phy_interface_t iface)
{
	struct phy_device *phy = of_phy_find_device(phy_np);
	int ret;

	if (!phy)
		return NULL;

	ret = phy_attach_direct(dev, phy, flags, iface);

	/* refcount is held by phy_attach_direct() on success */
	put_device(&phy->mdio.dev);

	return ret ? NULL : phy;
}
EXPORT_SYMBOL(of_phy_attach);

/*
 * of_phy_is_fixed_link() and of_phy_register_fixed_link() must
 * support two DT bindings:
 * - the old DT binding, where 'fixed-link' was a property with 5
 *   cells encoding various informations about the fixed PHY
 * - the new DT binding, where 'fixed-link' is a sub-node of the
 *   Ethernet device.
 */
bool of_phy_is_fixed_link(struct device_node *np)
{
	struct device_node *dn;
	int len, err;
	const char *managed;

	/* New binding */
	dn = of_get_child_by_name(np, "fixed-link");
	if (dn) {
		of_node_put(dn);
		return true;
	}

	err = of_property_read_string(np, "managed", &managed);
	if (err == 0 && strcmp(managed, "auto") != 0)
		return true;

	/* Old binding */
	if (of_get_property(np, "fixed-link", &len) &&
	    len == (5 * sizeof(__be32)))
		return true;

	return false;
}
EXPORT_SYMBOL(of_phy_is_fixed_link);

int of_phy_register_fixed_link(struct device_node *np)
{
	struct fixed_phy_status status = {};
	struct device_node *fixed_link_node;
	u32 fixed_link_prop[5];
	const char *managed;
	int link_gpio = -1;

	if (of_property_read_string(np, "managed", &managed) == 0 &&
	    strcmp(managed, "in-band-status") == 0) {
		/* status is zeroed, namely its .link member */
		goto register_phy;
	}

	/* New binding */
	fixed_link_node = of_get_child_by_name(np, "fixed-link");
	if (fixed_link_node) {
		status.link = 1;
		status.duplex = of_property_read_bool(fixed_link_node,
						      "full-duplex");
		if (of_property_read_u32(fixed_link_node, "speed",
					 &status.speed)) {
			of_node_put(fixed_link_node);
			return -EINVAL;
		}
		status.pause = of_property_read_bool(fixed_link_node, "pause");
		status.asym_pause = of_property_read_bool(fixed_link_node,
							  "asym-pause");
		link_gpio = of_get_named_gpio_flags(fixed_link_node,
						    "link-gpios", 0, NULL);
		of_node_put(fixed_link_node);
		if (link_gpio == -EPROBE_DEFER)
			return -EPROBE_DEFER;

		goto register_phy;
	}

	/* Old binding */
	if (of_property_read_u32_array(np, "fixed-link", fixed_link_prop,
				       ARRAY_SIZE(fixed_link_prop)) == 0) {
		status.link = 1;
		status.duplex = fixed_link_prop[1];
		status.speed  = fixed_link_prop[2];
		status.pause  = fixed_link_prop[3];
		status.asym_pause = fixed_link_prop[4];
		goto register_phy;
	}

	return -ENODEV;

register_phy:
	return PTR_ERR_OR_ZERO(fixed_phy_register(PHY_POLL, &status, link_gpio,
						  np));
}
EXPORT_SYMBOL(of_phy_register_fixed_link);

void of_phy_deregister_fixed_link(struct device_node *np)
{
	struct phy_device *phydev;

	phydev = of_phy_find_device(np);
	if (!phydev)
		return;

	fixed_phy_unregister(phydev);

	put_device(&phydev->mdio.dev);	/* of_phy_find_device() */
	phy_device_free(phydev);	/* fixed_phy_register() */
}
EXPORT_SYMBOL(of_phy_deregister_fixed_link);