include/dm/uclass.h - filogic/uboot - Gitiles

 /* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Copyright (c) 2013 Google, Inc
  *
  * (C) Copyright 2012
  * Pavel Herrmann <morpheus.ibis@gmail.com>
  */

 #ifndef _DM_UCLASS_H
 #define _DM_UCLASS_H

 #include <dm/ofnode.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 (do not access outside driver model)
  * @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 driver;
 struct udevice;

 /* Members of this uclass sequence themselves with aliases */
 #define DM_UC_FLAG_SEQ_ALIAS			(1 << 0)

 /* Members of this uclass without aliases don't get a sequence number */
 #define DM_UC_FLAG_NO_AUTO_SEQ			(1 << 1)

 /* Same as DM_FLAG_ALLOC_PRIV_DMA */
 #define DM_UC_FLAG_ALLOC_PRIV_DMA		(1 << 5)

 /**
  * 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
  * @pre_probe: Called before a new device is probed
  * @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
  * @child_pre_probe: Called before a child in this uclass is probed
  * @child_post_probe: Called after a child in this uclass is probed
  * @init: Called to set up the uclass
  * @destroy: Called to destroy the uclass
  * @priv_auto: 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: Each device can hold private data owned
  * by the uclass. If required this will be automatically allocated if this
  * value is non-zero.
  * @per_device_plat_auto: Each device can hold platform data
  * owned by the uclass as 'dev->uclass_plat'. If the value is non-zero,
  * then this will be automatically allocated.
  * @per_child_auto: Each child device (of a parent in this
  * uclass) can hold parent data for the device/uclass. This value is only
  * used as a fallback if this member is 0 in the driver.
  * @per_child_plat_auto: 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_plat pointer. This value is only used as
  * a fallback if this member is 0 in the driver.
  * @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 (*pre_probe)(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 (*child_post_probe)(struct udevice *dev);
 	int (*init)(struct uclass *class);
 	int (*destroy)(struct uclass *class);
 	int priv_auto;
 	int per_device_auto;
 	int per_device_plat_auto;
 	int per_child_auto;
 	int per_child_plat_auto;
 	uint32_t flags;
 };

 /* Declare a new uclass_driver */
 #define UCLASS_DRIVER(__name)						\
 	ll_entry_declare(struct uclass_driver, __name, uclass_driver)

 /*
  * These two macros DM_UCLASS_DRIVER_REF and DM_UCLASS_DRIVER_REF are only
  * allowed in code generated by dtoc, because the ordering is important and if
  * other instances creep in then they may mess up the ordering expected by dtoc.
  *
  * It is OK to use them with 'extern' though, since that does not actually
  * add a new record to the linker_list.
  */

 /**
  * DM_UCLASS_DRIVER_REF() - Get a reference to a uclass driver
  *
  * This is useful in data structures and code for referencing a uclass_driver at
  * build time. Before this is used, an extern UCLASS_DRIVER() must have been
  * declared.
  *
  * For example::
  *
  *   extern UCLASS_DRIVER(clk);
  *   struct uclass_driver *drvs[] = {
  *       DM_UCLASS_DRIVER_REF(clk),
  *   };
  *
  * @_name: Name of the uclass_driver. This must be a valid C identifier, used by
  *	the linker_list.
  * Return: struct uclass_driver * for the uclass driver
  */
 #define DM_UCLASS_DRIVER_REF(_name)					\
 	ll_entry_ref(struct uclass_driver, _name, uclass_driver)

 /**
  * uclass_get_priv() - Get the private data for a uclass
  *
  * @uc:	Uclass to check
  * Return: private data, or NULL if none
  */
 void *uclass_get_priv(const struct uclass *uc);

 /**
  * 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, -EDEADLK if driver model is not yet inited,
  * other -ve on other error
  */
 int uclass_get(enum uclass_id key, struct uclass **ucp);

 /**
  * uclass_get_name() - Get the name of a uclass driver
  *
  * @id: ID to look up
  * Return: the name of the uclass driver for that ID, or NULL if none
  */
 const char *uclass_get_name(enum uclass_id id);

 /**
  * uclass_get_by_namelen() - Look up a uclass by its driver name
  *
  * @name: Name to look up
  * @len: Length of @name (the uclass driver name must have the same length)
  * Return: the associated uclass ID, or UCLASS_INVALID if not found
  */
 enum uclass_id uclass_get_by_namelen(const char *name, int len);

 /**
  * uclass_get_by_name() - Look up a uclass by its driver name
  *
  * @name: Name to look up
  * Return: the associated uclass ID, or UCLASS_INVALID if not found
  */
 enum uclass_id uclass_get_by_name(const char *name);

 /**
  * 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_name() - Get a uclass device by its name
  *
  * This searches the devices in the uclass for one with the exactly given name.
  *
  * The device is probed to activate it ready for use.
  *
  * @id: ID to look up
  * @name: name of a device to get
  * @devp: Returns pointer to device (the first one with the name)
  * Return: 0 if OK, -ve on error
  */
 int uclass_get_device_by_name(enum uclass_id id, const char *name,
 			      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_get_device_by_ofnode() - 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 node to search for (if NULL 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_ofnode(enum uclass_id id, ofnode node,
 				struct udevice **devp);

 /**
  * uclass_get_device_by_phandle_id() - Get a uclass device by phandle id
  *
  * This searches the devices in the uclass for one with the given phandle id.
  *
  * The device is probed to activate it ready for use.
  *
  * @id:		uclass ID to look up
  * @phandle_id: the phandle id to look up
  * @devp:	Returns pointer to device (there is only one for each node).
  *		NULL if there is no such device.
  * Return:
  * 0 if OK, -ENODEV if there is no device match the phandle,
  * other -ve on error
  */
 int uclass_get_device_by_phandle_id(enum uclass_id id, uint phandle_id,
 				    struct udevice **devp);

 /**
  * uclass_get_device_by_phandle() - Get a uclass device by phandle
  *
  * This searches the devices in the uclass for one with the given phandle.
  *
  * The device is probed to activate it ready for use.
  *
  * @id: uclass ID to look up
  * @parent: Parent device containing the phandle pointer
  * @name: Name of property in the parent device node
  * @devp: Returns pointer to device (there is only one for each node)
  * Return: 0 if OK, -ENOENT if there is no @name present in the node, other
  * -ve on error
  */
 int uclass_get_device_by_phandle(enum uclass_id id, struct udevice *parent,
 				 const char *name, struct udevice **devp);

 /**
  * uclass_get_device_by_driver() - Get a uclass device for a driver
  *
  * This searches the devices in the uclass for one that uses the given
  * driver. Use DM_DRIVER_GET(name) for the @drv argument, where 'name' is
  * the driver name - as used in U_BOOT_DRIVER(name).
  *
  * The device is probed to activate it ready for use.
  *
  * @id: ID to look up
  * @drv: Driver to look for
  * @devp: Returns pointer to the first device with that driver
  * Return: 0 if OK, -ve on error
  */
 int uclass_get_device_by_driver(enum uclass_id id, const struct driver *drv,
 				struct udevice **devp);

 /**
  * uclass_first_device() - Get the first device in a uclass
  *
  * The device returned is probed if necessary, and ready for use
  *
  * This function is useful to start iterating through a list of devices which
  * are functioning correctly and can be probed.
  *
  * @id: Uclass ID to look up
  * @devp: Returns pointer to the first device in that uclass if no error
  * occurred, or NULL if there is no first device, or an error occurred with
  * that device.
  * Return: 0 if OK (found or not found), other -ve 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
  *
  * This function is useful to iterate through a list of devices which
  * are functioning correctly and can be probed.
  *
  * @devp: On entry, pointer to device to lookup. On exit, returns pointer
  * to the next device in the uclass if no error occurred, or NULL if there is
  * no next device, or an error occurred with that next device.
  * Return: 0 if OK (found or not found), other -ve on error
  */
 int uclass_next_device(struct udevice **devp);

 /**
  * uclass_first_device_err() - 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 found, -ENODEV if not found, other -ve on error
  */
 int uclass_first_device_err(enum uclass_id id, struct udevice **devp);

 /**
  * uclass_next_device_err() - 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 uclass if no error occurred, or NULL if
  * there is no next device.
  * Return: 0 if found, -ENODEV if not found, other -ve on error
  */
 int uclass_next_device_err(struct udevice **devp);

 /**
  * uclass_first_device_check() - Get the first device in a uclass
  *
  * The device returned is probed if necessary, and ready for use
  *
  * This function is useful to start iterating through a list of devices which
  * are functioning correctly and can be probed.
  *
  * @id: Uclass ID to look up
  * @devp: Returns pointer to the first device in that uclass, or NULL if there
  * is no first device
  * Return: 0 if OK (found or not found), other -ve on error. If an error occurs
  * it is still possible to move to the next device.
  */
 int uclass_first_device_check(enum uclass_id id, struct udevice **devp);

 /**
  * uclass_next_device_check() - Get the next device in a uclass
  *
  * The device returned is probed if necessary, and ready for use
  *
  * This function is useful to start iterating through a list of devices which
  * are functioning correctly and can be probed.
  *
  * @devp: On entry, pointer to device to lookup. On exit, returns pointer
  * to the next device in the uclass if any
  * Return: 0 if OK (found or not found), other -ve on error. If an error occurs
  * it is still possible to move to the next device.
  */
 int uclass_next_device_check(struct udevice **devp);

 /**
  * uclass_first_device_drvdata() - Find the first device with given driver data
  *
  * This searches through the devices for a particular uclass looking for one
  * that has the given driver data.
  *
  * @id: Uclass ID to check
  * @driver_data: Driver data to search for
  * @devp: Returns pointer to the first matching device in that uclass, if found
  * Return: 0 if found, -ENODEV if not found, other -ve on error
  */
 int uclass_first_device_drvdata(enum uclass_id id, ulong driver_data,
 				struct udevice **devp);

 /**
  * uclass_probe_all() - Probe all devices based on an uclass ID
  *
  * This function probes all devices associated with a uclass by
  * looking for its ID.
  *
  * @id: uclass ID to look up
  * Return: 0 if OK, other -ve on error
  */
 int uclass_probe_all(enum uclass_id id);

 /**
  * uclass_id_count() - Count the number of devices in a uclass
  *
  * @id: uclass ID to look up
  * Return: number of devices in that uclass (0 if none)
  */
 int uclass_id_count(enum uclass_id id);

 /**
  * uclass_id_foreach_dev() - iterate through devices of a given uclass ID
  *
  * This creates a for() loop which works through the available devices in
  * a uclass ID in order from start to end.
  *
  * If for some reason the uclass cannot be found, this does nothing.
  *
  * @id: enum uclass_id ID to use
  * @pos: struct udevice * to hold the current device. Set to NULL when there
  * are no more devices.
  * @uc: temporary uclass variable (``struct uclass *``)
  */
 #define uclass_id_foreach_dev(id, pos, uc) \
 	if (!uclass_get(id, &uc)) \
 		list_for_each_entry(pos, &uc->dev_head, uclass_node)

 /**
  * uclass_foreach_dev() - iterate through devices of a given uclass
  *
  * 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 (`struct uclass *`)
  */
 #define uclass_foreach_dev(pos, uc)	\
 	list_for_each_entry(pos, &uc->dev_head, uclass_node)

 /**
  * uclass_foreach_dev_safe() - safely iterate through devices of a given uclass
  *
  * This creates a for() loop which works through the available devices in
  * a uclass in order from start to end. Inside the loop, it is safe to remove
  * @pos if required.
  *
  * @pos: struct udevice * to hold the current device. Set to NULL when there
  * are no more devices.
  * @next: struct udevice * to hold the next next
  * @uc: uclass to scan (`struct uclass *`)
  */
 #define uclass_foreach_dev_safe(pos, next, uc)	\
 	list_for_each_entry_safe(pos, next, &uc->dev_head, uclass_node)

 /**
  * uclass_foreach_dev_probe() - iterate through devices of a given uclass ID
  *
  * This creates a for() loop which works through the available devices in
  * a uclass in order from start to end. Devices are probed if necessary,
  * and ready for use.
  *
  * @id: Uclass ID
  * @dev: struct udevice * to hold the current device. Set to NULL when there
  * are no more devices.
  */
 #define uclass_foreach_dev_probe(id, dev)	\
 	for (uclass_first_device(id, &dev); dev; \
 	     uclass_next_device(&dev))

 #endif
	/* SPDX-License-Identifier: GPL-2.0+ */
	/*
	* Copyright (c) 2013 Google, Inc
	*
	* (C) Copyright 2012
	* Pavel Herrmann <morpheus.ibis@gmail.com>
	*/

	#ifndef _DM_UCLASS_H
	#define _DM_UCLASS_H

	#include <dm/ofnode.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 (do not access outside driver model)
	* @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 driver;
	struct udevice;

	/* Members of this uclass sequence themselves with aliases */
	#define DM_UC_FLAG_SEQ_ALIAS (1 << 0)

	/* Members of this uclass without aliases don't get a sequence number */
	#define DM_UC_FLAG_NO_AUTO_SEQ (1 << 1)

	/* Same as DM_FLAG_ALLOC_PRIV_DMA */
	#define DM_UC_FLAG_ALLOC_PRIV_DMA (1 << 5)

	/**
	* 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
	* @pre_probe: Called before a new device is probed
	* @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
	* @child_pre_probe: Called before a child in this uclass is probed
	* @child_post_probe: Called after a child in this uclass is probed
	* @init: Called to set up the uclass
	* @destroy: Called to destroy the uclass
	* @priv_auto: 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: Each device can hold private data owned
	* by the uclass. If required this will be automatically allocated if this
	* value is non-zero.
	* @per_device_plat_auto: Each device can hold platform data
	* owned by the uclass as 'dev->uclass_plat'. If the value is non-zero,
	* then this will be automatically allocated.
	* @per_child_auto: Each child device (of a parent in this
	* uclass) can hold parent data for the device/uclass. This value is only
	* used as a fallback if this member is 0 in the driver.
	* @per_child_plat_auto: 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_plat pointer. This value is only used as
	* a fallback if this member is 0 in the driver.
	* @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 (pre_probe)(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 (child_post_probe)(struct udevice dev);
	int (init)(struct uclass class);
	int (destroy)(struct uclass class);
	int priv_auto;
	int per_device_auto;
	int per_device_plat_auto;
	int per_child_auto;
	int per_child_plat_auto;
	uint32_t flags;
	};

	/* Declare a new uclass_driver */
	#define UCLASS_DRIVER(__name) \
	ll_entry_declare(struct uclass_driver, __name, uclass_driver)

	/*
	* These two macros DM_UCLASS_DRIVER_REF and DM_UCLASS_DRIVER_REF are only
	* allowed in code generated by dtoc, because the ordering is important and if
	* other instances creep in then they may mess up the ordering expected by dtoc.
	*
	* It is OK to use them with 'extern' though, since that does not actually
	* add a new record to the linker_list.
	*/

	/**
	* DM_UCLASS_DRIVER_REF() - Get a reference to a uclass driver
	*
	* This is useful in data structures and code for referencing a uclass_driver at
	* build time. Before this is used, an extern UCLASS_DRIVER() must have been
	* declared.
	*
	* For example::
	*
	* extern UCLASS_DRIVER(clk);
	* struct uclass_driver *drvs[] = {
	* DM_UCLASS_DRIVER_REF(clk),
	* };
	*
	* @_name: Name of the uclass_driver. This must be a valid C identifier, used by
	* the linker_list.
	* Return: struct uclass_driver * for the uclass driver
	*/
	#define DM_UCLASS_DRIVER_REF(_name) \
	ll_entry_ref(struct uclass_driver, _name, uclass_driver)

	/**
	* uclass_get_priv() - Get the private data for a uclass
	*
	* @uc: Uclass to check
	* Return: private data, or NULL if none
	*/
	void uclass_get_priv(const struct uclass uc);

	/**
	* 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, -EDEADLK if driver model is not yet inited,
	* other -ve on other error
	*/
	int uclass_get(enum uclass_id key, struct uclass **ucp);

	/**
	* uclass_get_name() - Get the name of a uclass driver
	*
	* @id: ID to look up
	* Return: the name of the uclass driver for that ID, or NULL if none
	*/
	const char *uclass_get_name(enum uclass_id id);

	/**
	* uclass_get_by_namelen() - Look up a uclass by its driver name
	*
	* @name: Name to look up
	* @len: Length of @name (the uclass driver name must have the same length)
	* Return: the associated uclass ID, or UCLASS_INVALID if not found
	*/
	enum uclass_id uclass_get_by_namelen(const char *name, int len);

	/**
	* uclass_get_by_name() - Look up a uclass by its driver name
	*
	* @name: Name to look up
	* Return: the associated uclass ID, or UCLASS_INVALID if not found
	*/
	enum uclass_id uclass_get_by_name(const char *name);

	/**
	* 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_name() - Get a uclass device by its name
	*
	* This searches the devices in the uclass for one with the exactly given name.
	*
	* The device is probed to activate it ready for use.
	*
	* @id: ID to look up
	* @name: name of a device to get
	* @devp: Returns pointer to device (the first one with the name)
	* Return: 0 if OK, -ve on error
	*/
	int uclass_get_device_by_name(enum uclass_id id, const char *name,
	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_get_device_by_ofnode() - 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 node to search for (if NULL 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_ofnode(enum uclass_id id, ofnode node,
	struct udevice **devp);

	/**
	* uclass_get_device_by_phandle_id() - Get a uclass device by phandle id
	*
	* This searches the devices in the uclass for one with the given phandle id.
	*
	* The device is probed to activate it ready for use.
	*
	* @id: uclass ID to look up
	* @phandle_id: the phandle id to look up
	* @devp: Returns pointer to device (there is only one for each node).
	* NULL if there is no such device.
	* Return:
	* 0 if OK, -ENODEV if there is no device match the phandle,
	* other -ve on error
	*/
	int uclass_get_device_by_phandle_id(enum uclass_id id, uint phandle_id,
	struct udevice **devp);

	/**
	* uclass_get_device_by_phandle() - Get a uclass device by phandle
	*
	* This searches the devices in the uclass for one with the given phandle.
	*
	* The device is probed to activate it ready for use.
	*
	* @id: uclass ID to look up
	* @parent: Parent device containing the phandle pointer
	* @name: Name of property in the parent device node
	* @devp: Returns pointer to device (there is only one for each node)
	* Return: 0 if OK, -ENOENT if there is no @name present in the node, other
	* -ve on error
	*/
	int uclass_get_device_by_phandle(enum uclass_id id, struct udevice *parent,
	const char name, struct udevice *devp);

	/**
	* uclass_get_device_by_driver() - Get a uclass device for a driver
	*
	* This searches the devices in the uclass for one that uses the given
	* driver. Use DM_DRIVER_GET(name) for the @drv argument, where 'name' is
	* the driver name - as used in U_BOOT_DRIVER(name).
	*
	* The device is probed to activate it ready for use.
	*
	* @id: ID to look up
	* @drv: Driver to look for
	* @devp: Returns pointer to the first device with that driver
	* Return: 0 if OK, -ve on error
	*/
	int uclass_get_device_by_driver(enum uclass_id id, const struct driver *drv,
	struct udevice **devp);

	/**
	* uclass_first_device() - Get the first device in a uclass
	*
	* The device returned is probed if necessary, and ready for use
	*
	* This function is useful to start iterating through a list of devices which
	* are functioning correctly and can be probed.
	*
	* @id: Uclass ID to look up
	* @devp: Returns pointer to the first device in that uclass if no error
	* occurred, or NULL if there is no first device, or an error occurred with
	* that device.
	* Return: 0 if OK (found or not found), other -ve 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
	*
	* This function is useful to iterate through a list of devices which
	* are functioning correctly and can be probed.
	*
	* @devp: On entry, pointer to device to lookup. On exit, returns pointer
	* to the next device in the uclass if no error occurred, or NULL if there is
	* no next device, or an error occurred with that next device.
	* Return: 0 if OK (found or not found), other -ve on error
	*/
	int uclass_next_device(struct udevice **devp);

	/**
	* uclass_first_device_err() - 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 found, -ENODEV if not found, other -ve on error
	*/
	int uclass_first_device_err(enum uclass_id id, struct udevice **devp);

	/**
	* uclass_next_device_err() - 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 uclass if no error occurred, or NULL if
	* there is no next device.
	* Return: 0 if found, -ENODEV if not found, other -ve on error
	*/
	int uclass_next_device_err(struct udevice **devp);

	/**
	* uclass_first_device_check() - Get the first device in a uclass
	*
	* The device returned is probed if necessary, and ready for use
	*
	* This function is useful to start iterating through a list of devices which
	* are functioning correctly and can be probed.
	*
	* @id: Uclass ID to look up
	* @devp: Returns pointer to the first device in that uclass, or NULL if there
	* is no first device
	* Return: 0 if OK (found or not found), other -ve on error. If an error occurs
	* it is still possible to move to the next device.
	*/
	int uclass_first_device_check(enum uclass_id id, struct udevice **devp);

	/**
	* uclass_next_device_check() - Get the next device in a uclass
	*
	* The device returned is probed if necessary, and ready for use
	*
	* This function is useful to start iterating through a list of devices which
	* are functioning correctly and can be probed.
	*
	* @devp: On entry, pointer to device to lookup. On exit, returns pointer
	* to the next device in the uclass if any
	* Return: 0 if OK (found or not found), other -ve on error. If an error occurs
	* it is still possible to move to the next device.
	*/
	int uclass_next_device_check(struct udevice **devp);

	/**
	* uclass_first_device_drvdata() - Find the first device with given driver data
	*
	* This searches through the devices for a particular uclass looking for one
	* that has the given driver data.
	*
	* @id: Uclass ID to check
	* @driver_data: Driver data to search for
	* @devp: Returns pointer to the first matching device in that uclass, if found
	* Return: 0 if found, -ENODEV if not found, other -ve on error
	*/
	int uclass_first_device_drvdata(enum uclass_id id, ulong driver_data,
	struct udevice **devp);

	/**
	* uclass_probe_all() - Probe all devices based on an uclass ID
	*
	* This function probes all devices associated with a uclass by
	* looking for its ID.
	*
	* @id: uclass ID to look up
	* Return: 0 if OK, other -ve on error
	*/
	int uclass_probe_all(enum uclass_id id);

	/**
	* uclass_id_count() - Count the number of devices in a uclass
	*
	* @id: uclass ID to look up
	* Return: number of devices in that uclass (0 if none)
	*/
	int uclass_id_count(enum uclass_id id);

	/**
	* uclass_id_foreach_dev() - iterate through devices of a given uclass ID
	*
	* This creates a for() loop which works through the available devices in
	* a uclass ID in order from start to end.
	*
	* If for some reason the uclass cannot be found, this does nothing.
	*
	* @id: enum uclass_id ID to use
	* @pos: struct udevice * to hold the current device. Set to NULL when there
	* are no more devices.
	* @uc: temporary uclass variable (``struct uclass *``)
	*/
	#define uclass_id_foreach_dev(id, pos, uc) \
	if (!uclass_get(id, &uc)) \
	list_for_each_entry(pos, &uc->dev_head, uclass_node)

	/**
	* uclass_foreach_dev() - iterate through devices of a given uclass
	*
	* 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 (`struct uclass *`)
	*/
	#define uclass_foreach_dev(pos, uc) \
	list_for_each_entry(pos, &uc->dev_head, uclass_node)

	/**
	* uclass_foreach_dev_safe() - safely iterate through devices of a given uclass
	*
	* This creates a for() loop which works through the available devices in
	* a uclass in order from start to end. Inside the loop, it is safe to remove
	* @pos if required.
	*
	* @pos: struct udevice * to hold the current device. Set to NULL when there
	* are no more devices.
	* @next: struct udevice * to hold the next next
	* @uc: uclass to scan (`struct uclass *`)
	*/
	#define uclass_foreach_dev_safe(pos, next, uc) \
	list_for_each_entry_safe(pos, next, &uc->dev_head, uclass_node)

	/**
	* uclass_foreach_dev_probe() - iterate through devices of a given uclass ID
	*
	* This creates a for() loop which works through the available devices in
	* a uclass in order from start to end. Devices are probed if necessary,
	* and ready for use.
	*
	* @id: Uclass ID
	* @dev: struct udevice * to hold the current device. Set to NULL when there
	* are no more devices.
	*/
	#define uclass_foreach_dev_probe(id, dev) \
	for (uclass_first_device(id, &dev); dev; \
	uclass_next_device(&dev))

	#endif