/*
   * Copyright (c) 2013 Google, Inc
   *
   * (C) Copyright 2012
   * Pavel Herrmann <morpheus.ibis@gmail.com>
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #ifndef _DM_UCLASS_H
  #define _DM_UCLASS_H
  
  #include <dm/uclass-id.h>
  #include <linker_lists.h>
  #include <linux/list.h>
  
  /**
   * struct uclass - a U-Boot drive class, collecting together similar drivers
   *
   * A uclass provides an interface to a particular function, which is
   * implemented by one or more drivers. Every driver belongs to a uclass even
   * if it is the only driver in that uclass. An example uclass is GPIO, which
   * provides the ability to change read inputs, set and clear outputs, etc.
   * There may be drivers for on-chip SoC GPIO banks, I2C GPIO expanders and
   * PMIC IO lines, all made available in a unified way through the uclass.
   *
   * @priv: Private data for this uclass
   * @uc_drv: The driver for the uclass itself, not to be confused with a
   * 'struct driver'
   * @dev_head: List of devices in this uclass (devices are attached to their
   * uclass when their bind method is called)
   * @sibling_node: Next uclass in the linked list of uclasses
   */
  struct uclass {
  	void *priv;
  	struct uclass_driver *uc_drv;
  	struct list_head dev_head;
  	struct list_head sibling_node;
  };
  
  struct udevice;
  
  /* Members of this uclass sequence themselves with aliases */
  #define DM_UC_FLAG_SEQ_ALIAS			(1 << 0)
  
  /**
   * struct uclass_driver - Driver for the uclass
   *
   * A uclass_driver provides a consistent interface to a set of related
   * drivers.
   *
   * @name: Name of uclass driver
   * @id: ID number of this uclass
   * @post_bind: Called after a new device is bound to this uclass
   * @pre_unbind: Called before a device is unbound from this uclass
   * @post_probe: Called after a new device is probed
   * @pre_remove: Called before a device is removed
   * @child_post_bind: Called after a child is bound to a device in this uclass
   * @init: Called to set up the uclass
   * @destroy: Called to destroy the uclass
   * @priv_auto_alloc_size: If non-zero this is the size of the private data
   * to be allocated in the uclass's ->priv pointer. If zero, then the uclass
   * driver is responsible for allocating any data required.
   * @per_device_auto_alloc_size: Each device can hold private data owned
   * by the uclass. If required this will be automatically allocated if this
   * value is non-zero.
   * @per_child_auto_alloc_size: Each child device (of a parent in this
   * uclass) can hold parent data for the device/uclass. This value is only
   * used as a falback if this member is 0 in the driver.
   * @per_child_platdata_auto_alloc_size: A bus likes to store information about
   * its children. If non-zero this is the size of this data, to be allocated
   * in the child device's parent_platdata pointer. This value is only used as
   * a falback if this member is 0 in the driver.
   * @ops: Uclass operations, providing the consistent interface to devices
   * within the uclass.
   * @flags: Flags for this uclass (DM_UC_...)
   */
  struct uclass_driver {
  	const char *name;
  	enum uclass_id id;
  	int (*post_bind)(struct udevice *dev);
  	int (*pre_unbind)(struct udevice *dev);
  	int (*post_probe)(struct udevice *dev);
  	int (*pre_remove)(struct udevice *dev);
  	int (*child_post_bind)(struct udevice *dev);
  	int (*child_pre_probe)(struct udevice *dev);
  	int (*init)(struct uclass *class);
  	int (*destroy)(struct uclass *class);
  	int priv_auto_alloc_size;
  	int per_device_auto_alloc_size;
  	int per_child_auto_alloc_size;
  	int per_child_platdata_auto_alloc_size;
  	const void *ops;
  	uint32_t flags;
  };
  
  /* Declare a new uclass_driver */
  #define UCLASS_DRIVER(__name)						\
  	ll_entry_declare(struct uclass_driver, __name, uclass)
  
  /**
   * uclass_get() - Get a uclass based on an ID, creating it if needed
   *
   * Every uclass is identified by an ID, a number from 0 to n-1 where n is
   * the number of uclasses. This function allows looking up a uclass by its
   * ID.
   *
   * @key: ID to look up
   * @ucp: Returns pointer to uclass (there is only one per ID)
   * @return 0 if OK, -ve on error
   */
  int uclass_get(enum uclass_id key, struct uclass **ucp);
  
  /**
   * uclass_get_device() - Get a uclass device based on an ID and index
   *
   * The device is probed to activate it ready for use.
   *
   * @id: ID to look up
   * @index: Device number within that uclass (0=first)
   * @devp: Returns pointer to device (there is only one per for each ID)
   * @return 0 if OK, -ve on error
   */
  int uclass_get_device(enum uclass_id id, int index, struct udevice **devp);
  
  /**
   * uclass_get_device_by_seq() - Get a uclass device based on an ID and sequence
   *
   * If an active device has this sequence it will be returned. If there is no
   * such device then this will check for a device that is requesting this
   * sequence.
   *
   * The device is probed to activate it ready for use.
   *
   * @id: ID to look up
   * @seq: Sequence number to find (0=first)
   * @devp: Returns pointer to device (there is only one for each seq)
   * @return 0 if OK, -ve on error
   */
  int uclass_get_device_by_seq(enum uclass_id id, int seq, struct udevice **devp);
  
  /**
   * uclass_get_device_by_of_offset() - Get a uclass device by device tree node
   *
   * This searches the devices in the uclass for one attached to the given
   * device tree node.
   *
   * The device is probed to activate it ready for use.
   *
   * @id: ID to look up
   * @node: Device tree offset to search for (if -ve then -ENODEV is returned)
   * @devp: Returns pointer to device (there is only one for each node)
   * @return 0 if OK, -ve on error
   */
  int uclass_get_device_by_of_offset(enum uclass_id id, int node,
  				   struct udevice **devp);
  
  /**
   * uclass_first_device() - Get the first device in a uclass
   *
   * The device returned is probed if necessary, and ready for use
   *
   * @id: Uclass ID to look up
   * @devp: Returns pointer to the first device in that uclass, or NULL if none
   * @return 0 if OK (found or not found), -1 on error
   */
  int uclass_first_device(enum uclass_id id, struct udevice **devp);
  
  /**
   * uclass_next_device() - Get the next device in a uclass
   *
   * The device returned is probed if necessary, and ready for use
   *
   * @devp: On entry, pointer to device to lookup. On exit, returns pointer
   * to the next device in the same uclass, or NULL if none
   * @return 0 if OK (found or not found), -1 on error
   */
  int uclass_next_device(struct udevice **devp);
  
  /**
   * uclass_resolve_seq() - Resolve a device's sequence number
   *
   * On entry dev->seq is -1, and dev->req_seq may be -1 (to allocate a
   * sequence number automatically, or >= 0 to select a particular number.
   * If the requested sequence number is in use, then this device will
   * be allocated another one.
   *
   * Note that the device's seq value is not changed by this function.
   *
   * @dev: Device for which to allocate sequence number
   * @return sequence number allocated, or -ve on error
   */
  int uclass_resolve_seq(struct udevice *dev);
  
  /**
   * uclass_foreach_dev() - Helper function to iteration through devices
   *
   * This creates a for() loop which works through the available devices in
   * a uclass in order from start to end.
   *
   * @pos: struct udevice * to hold the current device. Set to NULL when there
   * are no more devices.
   * @uc: uclass to scan
   */
  #define uclass_foreach_dev(pos, uc)					\
  	for (pos = list_entry((&(uc)->dev_head)->next, typeof(*pos),	\
  			uclass_node);					\
  	     prefetch(pos->uclass_node.next),				\
  			&pos->uclass_node != (&(uc)->dev_head);		\
  	     pos = list_entry(pos->uclass_node.next, typeof(*pos),	\
  			uclass_node))
  
  #endif