/*
   * 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/module.h>
  
  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 (!phy || IS_ERR(phy))
  		return 1;
  
  	rc = irq_of_parse_and_map(child, 0);
  	if (rc > 0) {
  		phy->irq = rc;
  		if (mdio->irq)
  			mdio->irq[addr] = rc;
  	} else {
  		if (mdio->irq)
  			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->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 1;
  	}
  
  	dev_dbg(&mdio->dev, "registered phy %s at address %i
  ",
  		child->name, addr);
  
  	return 0;
  }
  
  int of_mdio_parse_addr(struct device *dev, const struct device_node *np)
  {
  	u32 addr;
  	int ret;
  
  	ret = of_property_read_u32(np, "reg", &addr);
  	if (ret < 0) {
  		dev_err(dev, "%s has invalid PHY address
  ", np->full_name);
  		return ret;
  	}
  
  	/* A PHY must have a reg property in the range [0-31] */
  	if (addr >= PHY_MAX_ADDR) {
  		dev_err(dev, "%s PHY address %i is too large
  ",
  			np->full_name, addr);
  		return -EINVAL;
  	}
  
  	return addr;
  }
  EXPORT_SYMBOL(of_mdio_parse_addr);
  
  /**
   * 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;
  	const __be32 *paddr;
  	bool scanphys = false;
  	int addr, rc, i;
  
  	/* 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;
  
  	/* Clear all the IRQ properties */
  	if (mdio->irq)
  		for (i=0; i<PHY_MAX_ADDR; i++)
  			mdio->irq[i] = PHY_POLL;
  
  	mdio->dev.of_node = np;
  
  	/* Register the MDIO bus */
  	rc = mdiobus_register(mdio);
  	if (rc)
  		return rc;
  
  	/* Loop over the child nodes and register a phy_device for each one */
  	for_each_available_child_of_node(np, child) {
  		addr = of_mdio_parse_addr(&mdio->dev, child);
  		if (addr < 0) {
  			scanphys = true;
  			continue;
  		}
  
  		rc = of_mdiobus_register_phy(mdio, child, addr);
  		if (rc)
  			continue;
  	}
  
  	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 */
  		paddr = of_get_property(child, "reg", NULL);
  		if (paddr)
  			continue;
  
  		for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
  			/* skip already registered PHYs */
  			if (mdio->phy_map[addr])
  				continue;
  
  			/* be noisy to encourage people to set reg property */
  			dev_info(&mdio->dev, "scan phy %s at address %i
  ",
  				 child->name, addr);
  
  			rc = of_mdiobus_register_phy(mdio, child, addr);
  			if (rc)
  				continue;
  		}
  	}
  
  	return 0;
  }
  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;
  	if (!phy_np)
  		return NULL;
  
  	d = bus_find_device(&mdio_bus_type, NULL, phy_np, of_phy_match);
  	return d ? to_phy_device(d) : 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
   * @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->dev);
  
  	return ret ? NULL : phy;
  }
  EXPORT_SYMBOL(of_phy_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->dev);
  
  	return ret ? NULL : phy;
  }
  EXPORT_SYMBOL(of_phy_attach);
  
  #if defined(CONFIG_FIXED_PHY)
  /*
   * 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;
  	const __be32 *fixed_link_prop;
  	int link_gpio;
  	int len, err;
  	struct phy_device *phy;
  	const char *managed;
  
  	err = of_property_read_string(np, "managed", &managed);
  	if (err == 0) {
  		if (strcmp(managed, "in-band-status") == 0) {
  			/* status is zeroed, namely its .link member */
  			phy = fixed_phy_register(PHY_POLL, &status, -1, np);
  			return IS_ERR(phy) ? PTR_ERR(phy) : 0;
  		}
  	}
  
  	/* 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))
  			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;
  
  		phy = fixed_phy_register(PHY_POLL, &status, link_gpio, np);
  		return IS_ERR(phy) ? PTR_ERR(phy) : 0;
  	}
  
  	/* Old binding */
  	fixed_link_prop = of_get_property(np, "fixed-link", &len);
  	if (fixed_link_prop && len == (5 * sizeof(__be32))) {
  		status.link = 1;
  		status.duplex = be32_to_cpu(fixed_link_prop[1]);
  		status.speed = be32_to_cpu(fixed_link_prop[2]);
  		status.pause = be32_to_cpu(fixed_link_prop[3]);
  		status.asym_pause = be32_to_cpu(fixed_link_prop[4]);
  		phy = fixed_phy_register(PHY_POLL, &status, -1, np);
  		return IS_ERR(phy) ? PTR_ERR(phy) : 0;
  	}
  
  	return -ENODEV;
  }
  EXPORT_SYMBOL(of_phy_register_fixed_link);
  #endif