include/dm/device.h - platform/external/u-boot - Gitiles

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

 #ifndef _DM_DEVICE_H
 #define _DM_DEVICE_H

 #include <dm/uclass-id.h>
 #include <fdtdec.h>
 #include <linker_lists.h>
 #include <linux/list.h>

 struct driver_info;

 /* Driver is active (probed). Cleared when it is removed */
 #define DM_FLAG_ACTIVATED	(1 << 0)

 /* DM is responsible for allocating and freeing platdata */
 #define DM_FLAG_ALLOC_PDATA	(1 << 1)

 /* DM should init this device prior to relocation */
 #define DM_FLAG_PRE_RELOC	(1 << 2)

 /* DM is responsible for allocating and freeing parent_platdata */
 #define DM_FLAG_ALLOC_PARENT_PDATA	(1 << 3)

 /* DM is responsible for allocating and freeing uclass_platdata */
 #define DM_FLAG_ALLOC_UCLASS_PDATA	(1 << 4)

 /* Allocate driver private data on a DMA boundary */
 #define DM_FLAG_ALLOC_PRIV_DMA	(1 << 5)

 /* Device is bound */
 #define DM_FLAG_BOUND	(1 << 6)

 /**
  * struct udevice - An instance of a driver
  *
  * This holds information about a device, which is a driver bound to a
  * particular port or peripheral (essentially a driver instance).
  *
  * A device will come into existence through a 'bind' call, either due to
  * a U_BOOT_DEVICE() macro (in which case platdata is non-NULL) or a node
  * in the device tree (in which case of_offset is >= 0). In the latter case
  * we translate the device tree information into platdata in a function
  * implemented by the driver ofdata_to_platdata method (called just before the
  * probe method if the device has a device tree node.
  *
  * All three of platdata, priv and uclass_priv can be allocated by the
  * driver, or you can use the auto_alloc_size members of struct driver and
  * struct uclass_driver to have driver model do this automatically.
  *
  * @driver: The driver used by this device
  * @name: Name of device, typically the FDT node name
  * @platdata: Configuration data for this device
  * @parent_platdata: The parent bus's configuration data for this device
  * @uclass_platdata: The uclass's configuration data for this device
  * @of_offset: Device tree node offset for this device (- for none)
  * @driver_data: Driver data word for the entry that matched this device with
  *		its driver
  * @parent: Parent of this device, or NULL for the top level device
  * @priv: Private data for this device
  * @uclass: Pointer to uclass for this device
  * @uclass_priv: The uclass's private data for this device
  * @parent_priv: The parent's private data for this device
  * @uclass_node: Used by uclass to link its devices
  * @child_head: List of children of this device
  * @sibling_node: Next device in list of all devices
  * @flags: Flags for this device DM_FLAG_...
  * @req_seq: Requested sequence number for this device (-1 = any)
  * @seq: Allocated sequence number for this device (-1 = none). This is set up
  * when the device is probed and will be unique within the device's uclass.
  */
 struct udevice {
 	const struct driver *driver;
 	const char *name;
 	void *platdata;
 	void *parent_platdata;
 	void *uclass_platdata;
 	int of_offset;
 	ulong driver_data;
 	struct udevice *parent;
 	void *priv;
 	struct uclass *uclass;
 	void *uclass_priv;
 	void *parent_priv;
 	struct list_head uclass_node;
 	struct list_head child_head;
 	struct list_head sibling_node;
 	uint32_t flags;
 	int req_seq;
 	int seq;
 	struct list_head devres_head;
 };

 /* Maximum sequence number supported */
 #define DM_MAX_SEQ	999

 /* Returns the operations for a device */
 #define device_get_ops(dev)	(dev->driver->ops)

 /* Returns non-zero if the device is active (probed and not removed) */
 #define device_active(dev)	((dev)->flags & DM_FLAG_ACTIVATED)

 /**
  * struct udevice_id - Lists the compatible strings supported by a driver
  * @compatible: Compatible string
  * @data: Data for this compatible string
  */
 struct udevice_id {
 	const char *compatible;
 	ulong data;
 };

 #ifdef CONFIG_OF_CONTROL
 #define of_match_ptr(_ptr)	(_ptr)
 #else
 #define of_match_ptr(_ptr)	NULL
 #endif /* CONFIG_OF_CONTROL */

 /**
  * struct driver - A driver for a feature or peripheral
  *
  * This holds methods for setting up a new device, and also removing it.
  * The device needs information to set itself up - this is provided either
  * by platdata or a device tree node (which we find by looking up
  * matching compatible strings with of_match).
  *
  * Drivers all belong to a uclass, representing a class of devices of the
  * same type. Common elements of the drivers can be implemented in the uclass,
  * or the uclass can provide a consistent interface to the drivers within
  * it.
  *
  * @name: Device name
  * @id: Identiies the uclass we belong to
  * @of_match: List of compatible strings to match, and any identifying data
  * for each.
  * @bind: Called to bind a device to its driver
  * @probe: Called to probe a device, i.e. activate it
  * @remove: Called to remove a device, i.e. de-activate it
  * @unbind: Called to unbind a device from its driver
  * @ofdata_to_platdata: Called before probe to decode device tree data
  * @child_post_bind: Called after a new child has been bound
  * @child_pre_probe: Called before a child device is probed. The device has
  * memory allocated but it has not yet been probed.
  * @child_post_remove: Called after a child device is removed. The device
  * has memory allocated but its device_remove() method has been called.
  * @priv_auto_alloc_size: If non-zero this is the size of the private data
  * to be allocated in the device's ->priv pointer. If zero, then the driver
  * is responsible for allocating any data required.
  * @platdata_auto_alloc_size: If non-zero this is the size of the
  * platform data to be allocated in the device's ->platdata pointer.
  * This is typically only useful for device-tree-aware drivers (those with
  * an of_match), since drivers which use platdata will have the data
  * provided in the U_BOOT_DEVICE() instantiation.
  * @per_child_auto_alloc_size: Each device can hold private data owned by
  * its parent. If required this will be automatically allocated if this
  * value is non-zero.
  * TODO(sjg@chromium.org): I'm considering dropping this, and just having
  * device_probe_child() pass it in. So far the use case for allocating it
  * is SPI, but I found that unsatisfactory. Since it is here I will leave it
  * until things are clearer.
  * @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's parent_platdata pointer.
  * @ops: Driver-specific operations. This is typically a list of function
  * pointers defined by the driver, to implement driver functions required by
  * the uclass.
  * @flags: driver flags - see DM_FLAGS_...
  */
 struct driver {
 	char *name;
 	enum uclass_id id;
 	const struct udevice_id *of_match;
 	int (*bind)(struct udevice *dev);
 	int (*probe)(struct udevice *dev);
 	int (*remove)(struct udevice *dev);
 	int (*unbind)(struct udevice *dev);
 	int (*ofdata_to_platdata)(struct udevice *dev);
 	int (*child_post_bind)(struct udevice *dev);
 	int (*child_pre_probe)(struct udevice *dev);
 	int (*child_post_remove)(struct udevice *dev);
 	int priv_auto_alloc_size;
 	int platdata_auto_alloc_size;
 	int per_child_auto_alloc_size;
 	int per_child_platdata_auto_alloc_size;
 	const void *ops;	/* driver-specific operations */
 	uint32_t flags;
 };

 /* Declare a new U-Boot driver */
 #define U_BOOT_DRIVER(__name)						\
 	ll_entry_declare(struct driver, __name, driver)

 /**
  * dev_get_platdata() - Get the platform data for a device
  *
  * This checks that dev is not NULL, but no other checks for now
  *
  * @dev		Device to check
  * @return platform data, or NULL if none
  */
 void *dev_get_platdata(struct udevice *dev);

 /**
  * dev_get_parent_platdata() - Get the parent platform data for a device
  *
  * This checks that dev is not NULL, but no other checks for now
  *
  * @dev		Device to check
  * @return parent's platform data, or NULL if none
  */
 void *dev_get_parent_platdata(struct udevice *dev);

 /**
  * dev_get_uclass_platdata() - Get the uclass platform data for a device
  *
  * This checks that dev is not NULL, but no other checks for now
  *
  * @dev		Device to check
  * @return uclass's platform data, or NULL if none
  */
 void *dev_get_uclass_platdata(struct udevice *dev);

 /**
  * dev_get_parentdata() - Get the parent data for a device
  *
  * The parent data is data stored in the device but owned by the parent.
  * For example, a USB device may have parent data which contains information
  * about how to talk to the device over USB.
  *
  * This checks that dev is not NULL, but no other checks for now
  *
  * @dev		Device to check
  * @return parent data, or NULL if none
  */
 void *dev_get_parentdata(struct udevice *dev);

 /**
  * dev_get_priv() - Get the private data for a device
  *
  * This checks that dev is not NULL, but no other checks for now
  *
  * @dev		Device to check
  * @return private data, or NULL if none
  */
 void *dev_get_priv(struct udevice *dev);

 /**
  * struct dev_get_parent() - Get the parent of a device
  *
  * @child:	Child to check
  * @return parent of child, or NULL if this is the root device
  */
 struct udevice *dev_get_parent(struct udevice *child);

 /**
  * dev_get_uclass_priv() - Get the private uclass data for a device
  *
  * This checks that dev is not NULL, but no other checks for now
  *
  * @dev		Device to check
  * @return private uclass data for this device, or NULL if none
  */
 void *dev_get_uclass_priv(struct udevice *dev);

 /**
  * dev_get_driver_data() - get the driver data used to bind a device
  *
  * When a device is bound using a device tree node, it matches a
  * particular compatible string as in struct udevice_id. This function
  * returns the associated data value for that compatible string. This is
  * the 'data' field in struct udevice_id.
  *
  * For USB devices, this is the driver_info field in struct usb_device_id.
  *
  * @dev:	Device to check
  */
 ulong dev_get_driver_data(struct udevice *dev);

 /**
  * dev_get_driver_ops() - get the device's driver's operations
  *
  * This checks that dev is not NULL, and returns the pointer to device's
  * driver's operations.
  *
  * @dev:	Device to check
  * @return void pointer to driver's operations or NULL for NULL-dev or NULL-ops
  */
 const void *dev_get_driver_ops(struct udevice *dev);

 /*
  * device_get_uclass_id() - return the uclass ID of a device
  *
  * @dev:	Device to check
  * @return uclass ID for the device
  */
 enum uclass_id device_get_uclass_id(struct udevice *dev);

 /*
  * dev_get_uclass_name() - return the uclass name of a device
  *
  * This checks that dev is not NULL.
  *
  * @dev:	Device to check
  * @return  pointer to the uclass name for the device
  */
 const char *dev_get_uclass_name(struct udevice *dev);

 /**
  * device_get_child() - Get the child of a device by index
  *
  * Returns the numbered child, 0 being the first. This does not use
  * sequence numbers, only the natural order.
  *
  * @dev:	Parent device to check
  * @index:	Child index
  * @devp:	Returns pointer to device
  * @return 0 if OK, -ENODEV if no such device, other error if the device fails
  *	   to probe
  */
 int device_get_child(struct udevice *parent, int index, struct udevice **devp);

 /**
  * device_find_child_by_seq() - Find a child device based on a sequence
  *
  * This searches for a device with the given seq or req_seq.
  *
  * For seq, if an active device has this sequence it will be returned.
  * If there is no such device then this will return -ENODEV.
  *
  * For req_seq, if a device (whether activated or not) has this req_seq
  * value, that device will be returned. This is a strong indication that
  * the device will receive that sequence when activated.
  *
  * @parent: Parent device
  * @seq_or_req_seq: Sequence number to find (0=first)
  * @find_req_seq: true to find req_seq, false to find seq
  * @devp: Returns pointer to device (there is only one per for each seq).
  * Set to NULL if none is found
  * @return 0 if OK, -ve on error
  */
 int device_find_child_by_seq(struct udevice *parent, int seq_or_req_seq,
 			     bool find_req_seq, struct udevice **devp);

 /**
  * device_get_child_by_seq() - Get a child device based on a 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.
  *
  * @parent: Parent device
  * @seq: Sequence number to find (0=first)
  * @devp: Returns pointer to device (there is only one per for each seq)
  * Set to NULL if none is found
  * @return 0 if OK, -ve on error
  */
 int device_get_child_by_seq(struct udevice *parent, int seq,
 			    struct udevice **devp);

 /**
  * device_find_child_by_of_offset() - Find a child device based on FDT offset
  *
  * Locates a child device by its device tree offset.
  *
  * @parent: Parent device
  * @of_offset: Device tree offset to find
  * @devp: Returns pointer to device if found, otherwise this is set to NULL
  * @return 0 if OK, -ve on error
  */
 int device_find_child_by_of_offset(struct udevice *parent, int of_offset,
 				   struct udevice **devp);

 /**
  * device_get_child_by_of_offset() - Get a child device based on FDT offset
  *
  * Locates a child device by its device tree offset.
  *
  * The device is probed to activate it ready for use.
  *
  * @parent: Parent device
  * @of_offset: Device tree offset to find
  * @devp: Returns pointer to device if found, otherwise this is set to NULL
  * @return 0 if OK, -ve on error
  */
 int device_get_child_by_of_offset(struct udevice *parent, int of_offset,
 				  struct udevice **devp);

 /**
  * device_get_global_by_of_offset() - Get a device based on FDT offset
  *
  * Locates a device by its device tree offset, searching globally throughout
  * the all driver model devices.
  *
  * The device is probed to activate it ready for use.
  *
  * @of_offset: Device tree offset to find
  * @devp: Returns pointer to device if found, otherwise this is set to NULL
  * @return 0 if OK, -ve on error
  */
 int device_get_global_by_of_offset(int of_offset, struct udevice **devp);

 /**
  * device_find_first_child() - Find the first child of a device
  *
  * @parent: Parent device to search
  * @devp: Returns first child device, or NULL if none
  * @return 0
  */
 int device_find_first_child(struct udevice *parent, struct udevice **devp);

 /**
  * device_find_next_child() - Find the next child of a device
  *
  * @devp: Pointer to previous child device on entry. Returns pointer to next
  *		child device, or NULL if none
  * @return 0
  */
 int device_find_next_child(struct udevice **devp);

 /**
  * dev_get_addr() - Get the reg property of a device
  *
  * @dev: Pointer to a device
  *
  * @return addr
  */
 fdt_addr_t dev_get_addr(struct udevice *dev);

 /**
  * device_has_children() - check if a device has any children
  *
  * @dev:	Device to check
  * @return true if the device has one or more children
  */
 bool device_has_children(struct udevice *dev);

 /**
  * device_has_active_children() - check if a device has any active children
  *
  * @dev:	Device to check
  * @return true if the device has one or more children and at least one of
  * them is active (probed).
  */
 bool device_has_active_children(struct udevice *dev);

 /**
  * device_is_last_sibling() - check if a device is the last sibling
  *
  * This function can be useful for display purposes, when special action needs
  * to be taken when displaying the last sibling. This can happen when a tree
  * view of devices is being displayed.
  *
  * @dev:	Device to check
  * @return true if there are no more siblings after this one - i.e. is it
  * last in the list.
  */
 bool device_is_last_sibling(struct udevice *dev);

 /* device resource management */
 typedef void (*dr_release_t)(struct udevice *dev, void *res);
 typedef int (*dr_match_t)(struct udevice *dev, void *res, void *match_data);

 #ifdef CONFIG_DEBUG_DEVRES
 void *__devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
 		     const char *name);
 #define _devres_alloc(release, size, gfp) \
 	__devres_alloc(release, size, gfp, #release)
 #else
 void *_devres_alloc(dr_release_t release, size_t size, gfp_t gfp);
 #endif

 /**
  * devres_alloc - Allocate device resource data
  * @release: Release function devres will be associated with
  * @size: Allocation size
  * @gfp: Allocation flags
  *
  * Allocate devres of @size bytes.  The allocated area is associated
  * with @release.  The returned pointer can be passed to
  * other devres_*() functions.
  *
  * RETURNS:
  * Pointer to allocated devres on success, NULL on failure.
  */
 #define devres_alloc(release, size, gfp) \
 	_devres_alloc(release, size, gfp | __GFP_ZERO)

 /**
  * devres_free - Free device resource data
  * @res: Pointer to devres data to free
  *
  * Free devres created with devres_alloc().
  */
 void devres_free(void *res);

 /**
  * devres_add - Register device resource
  * @dev: Device to add resource to
  * @res: Resource to register
  *
  * Register devres @res to @dev.  @res should have been allocated
  * using devres_alloc().  On driver detach, the associated release
  * function will be invoked and devres will be freed automatically.
  */
 void devres_add(struct udevice *dev, void *res);

 /**
  * devres_find - Find device resource
  * @dev: Device to lookup resource from
  * @release: Look for resources associated with this release function
  * @match: Match function (optional)
  * @match_data: Data for the match function
  *
  * Find the latest devres of @dev which is associated with @release
  * and for which @match returns 1.  If @match is NULL, it's considered
  * to match all.
  *
  * RETURNS:
  * Pointer to found devres, NULL if not found.
  */
 void *devres_find(struct udevice *dev, dr_release_t release,
 		  dr_match_t match, void *match_data);

 /**
  * devres_get - Find devres, if non-existent, add one atomically
  * @dev: Device to lookup or add devres for
  * @new_res: Pointer to new initialized devres to add if not found
  * @match: Match function (optional)
  * @match_data: Data for the match function
  *
  * Find the latest devres of @dev which has the same release function
  * as @new_res and for which @match return 1.  If found, @new_res is
  * freed; otherwise, @new_res is added atomically.
  *
  * RETURNS:
  * Pointer to found or added devres.
  */
 void *devres_get(struct udevice *dev, void *new_res,
 		 dr_match_t match, void *match_data);

 /**
  * devres_remove - Find a device resource and remove it
  * @dev: Device to find resource from
  * @release: Look for resources associated with this release function
  * @match: Match function (optional)
  * @match_data: Data for the match function
  *
  * Find the latest devres of @dev associated with @release and for
  * which @match returns 1.  If @match is NULL, it's considered to
  * match all.  If found, the resource is removed atomically and
  * returned.
  *
  * RETURNS:
  * Pointer to removed devres on success, NULL if not found.
  */
 void *devres_remove(struct udevice *dev, dr_release_t release,
 		    dr_match_t match, void *match_data);

 /**
  * devres_destroy - Find a device resource and destroy it
  * @dev: Device to find resource from
  * @release: Look for resources associated with this release function
  * @match: Match function (optional)
  * @match_data: Data for the match function
  *
  * Find the latest devres of @dev associated with @release and for
  * which @match returns 1.  If @match is NULL, it's considered to
  * match all.  If found, the resource is removed atomically and freed.
  *
  * Note that the release function for the resource will not be called,
  * only the devres-allocated data will be freed.  The caller becomes
  * responsible for freeing any other data.
  *
  * RETURNS:
  * 0 if devres is found and freed, -ENOENT if not found.
  */
 int devres_destroy(struct udevice *dev, dr_release_t release,
 		   dr_match_t match, void *match_data);

 /**
  * devres_release - Find a device resource and destroy it, calling release
  * @dev: Device to find resource from
  * @release: Look for resources associated with this release function
  * @match: Match function (optional)
  * @match_data: Data for the match function
  *
  * Find the latest devres of @dev associated with @release and for
  * which @match returns 1.  If @match is NULL, it's considered to
  * match all.  If found, the resource is removed atomically, the
  * release function called and the resource freed.
  *
  * RETURNS:
  * 0 if devres is found and freed, -ENOENT if not found.
  */
 int devres_release(struct udevice *dev, dr_release_t release,
 		   dr_match_t match, void *match_data);

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

	#ifndef _DM_DEVICE_H
	#define _DM_DEVICE_H

	#include <dm/uclass-id.h>
	#include <fdtdec.h>
	#include <linker_lists.h>
	#include <linux/list.h>

	struct driver_info;

	/* Driver is active (probed). Cleared when it is removed */
	#define DM_FLAG_ACTIVATED (1 << 0)

	/* DM is responsible for allocating and freeing platdata */
	#define DM_FLAG_ALLOC_PDATA (1 << 1)

	/* DM should init this device prior to relocation */
	#define DM_FLAG_PRE_RELOC (1 << 2)

	/* DM is responsible for allocating and freeing parent_platdata */
	#define DM_FLAG_ALLOC_PARENT_PDATA (1 << 3)

	/* DM is responsible for allocating and freeing uclass_platdata */
	#define DM_FLAG_ALLOC_UCLASS_PDATA (1 << 4)

	/* Allocate driver private data on a DMA boundary */
	#define DM_FLAG_ALLOC_PRIV_DMA (1 << 5)

	/* Device is bound */
	#define DM_FLAG_BOUND (1 << 6)

	/**
	* struct udevice - An instance of a driver
	*
	* This holds information about a device, which is a driver bound to a
	* particular port or peripheral (essentially a driver instance).
	*
	* A device will come into existence through a 'bind' call, either due to
	* a U_BOOT_DEVICE() macro (in which case platdata is non-NULL) or a node
	* in the device tree (in which case of_offset is >= 0). In the latter case
	* we translate the device tree information into platdata in a function
	* implemented by the driver ofdata_to_platdata method (called just before the
	* probe method if the device has a device tree node.
	*
	* All three of platdata, priv and uclass_priv can be allocated by the
	* driver, or you can use the auto_alloc_size members of struct driver and
	* struct uclass_driver to have driver model do this automatically.
	*
	* @driver: The driver used by this device
	* @name: Name of device, typically the FDT node name
	* @platdata: Configuration data for this device
	* @parent_platdata: The parent bus's configuration data for this device
	* @uclass_platdata: The uclass's configuration data for this device
	* @of_offset: Device tree node offset for this device (- for none)
	* @driver_data: Driver data word for the entry that matched this device with
	* its driver
	* @parent: Parent of this device, or NULL for the top level device
	* @priv: Private data for this device
	* @uclass: Pointer to uclass for this device
	* @uclass_priv: The uclass's private data for this device
	* @parent_priv: The parent's private data for this device
	* @uclass_node: Used by uclass to link its devices
	* @child_head: List of children of this device
	* @sibling_node: Next device in list of all devices
	* @flags: Flags for this device DM_FLAG_...
	* @req_seq: Requested sequence number for this device (-1 = any)
	* @seq: Allocated sequence number for this device (-1 = none). This is set up
	* when the device is probed and will be unique within the device's uclass.
	*/
	struct udevice {
	const struct driver *driver;
	const char *name;
	void *platdata;
	void *parent_platdata;
	void *uclass_platdata;
	int of_offset;
	ulong driver_data;
	struct udevice *parent;
	void *priv;
	struct uclass *uclass;
	void *uclass_priv;
	void *parent_priv;
	struct list_head uclass_node;
	struct list_head child_head;
	struct list_head sibling_node;
	uint32_t flags;
	int req_seq;
	int seq;
	struct list_head devres_head;
	};

	/* Maximum sequence number supported */
	#define DM_MAX_SEQ 999

	/* Returns the operations for a device */
	#define device_get_ops(dev) (dev->driver->ops)

	/* Returns non-zero if the device is active (probed and not removed) */
	#define device_active(dev) ((dev)->flags & DM_FLAG_ACTIVATED)

	/**
	* struct udevice_id - Lists the compatible strings supported by a driver
	* @compatible: Compatible string
	* @data: Data for this compatible string
	*/
	struct udevice_id {
	const char *compatible;
	ulong data;
	};

	#ifdef CONFIG_OF_CONTROL
	#define of_match_ptr(_ptr) (_ptr)
	#else
	#define of_match_ptr(_ptr) NULL
	#endif /* CONFIG_OF_CONTROL */

	/**
	* struct driver - A driver for a feature or peripheral
	*
	* This holds methods for setting up a new device, and also removing it.
	* The device needs information to set itself up - this is provided either
	* by platdata or a device tree node (which we find by looking up
	* matching compatible strings with of_match).
	*
	* Drivers all belong to a uclass, representing a class of devices of the
	* same type. Common elements of the drivers can be implemented in the uclass,
	* or the uclass can provide a consistent interface to the drivers within
	* it.
	*
	* @name: Device name
	* @id: Identiies the uclass we belong to
	* @of_match: List of compatible strings to match, and any identifying data
	* for each.
	* @bind: Called to bind a device to its driver
	* @probe: Called to probe a device, i.e. activate it
	* @remove: Called to remove a device, i.e. de-activate it
	* @unbind: Called to unbind a device from its driver
	* @ofdata_to_platdata: Called before probe to decode device tree data
	* @child_post_bind: Called after a new child has been bound
	* @child_pre_probe: Called before a child device is probed. The device has
	* memory allocated but it has not yet been probed.
	* @child_post_remove: Called after a child device is removed. The device
	* has memory allocated but its device_remove() method has been called.
	* @priv_auto_alloc_size: If non-zero this is the size of the private data
	* to be allocated in the device's ->priv pointer. If zero, then the driver
	* is responsible for allocating any data required.
	* @platdata_auto_alloc_size: If non-zero this is the size of the
	* platform data to be allocated in the device's ->platdata pointer.
	* This is typically only useful for device-tree-aware drivers (those with
	* an of_match), since drivers which use platdata will have the data
	* provided in the U_BOOT_DEVICE() instantiation.
	* @per_child_auto_alloc_size: Each device can hold private data owned by
	* its parent. If required this will be automatically allocated if this
	* value is non-zero.
	* TODO(sjg@chromium.org): I'm considering dropping this, and just having
	* device_probe_child() pass it in. So far the use case for allocating it
	* is SPI, but I found that unsatisfactory. Since it is here I will leave it
	* until things are clearer.
	* @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's parent_platdata pointer.
	* @ops: Driver-specific operations. This is typically a list of function
	* pointers defined by the driver, to implement driver functions required by
	* the uclass.
	* @flags: driver flags - see DM_FLAGS_...
	*/
	struct driver {
	char *name;
	enum uclass_id id;
	const struct udevice_id *of_match;
	int (bind)(struct udevice dev);
	int (probe)(struct udevice dev);
	int (remove)(struct udevice dev);
	int (unbind)(struct udevice dev);
	int (ofdata_to_platdata)(struct udevice dev);
	int (child_post_bind)(struct udevice dev);
	int (child_pre_probe)(struct udevice dev);
	int (child_post_remove)(struct udevice dev);
	int priv_auto_alloc_size;
	int platdata_auto_alloc_size;
	int per_child_auto_alloc_size;
	int per_child_platdata_auto_alloc_size;
	const void ops; / driver-specific operations */
	uint32_t flags;
	};

	/* Declare a new U-Boot driver */
	#define U_BOOT_DRIVER(__name) \
	ll_entry_declare(struct driver, __name, driver)

	/**
	* dev_get_platdata() - Get the platform data for a device
	*
	* This checks that dev is not NULL, but no other checks for now
	*
	* @dev Device to check
	* @return platform data, or NULL if none
	*/
	void dev_get_platdata(struct udevice dev);

	/**
	* dev_get_parent_platdata() - Get the parent platform data for a device
	*
	* This checks that dev is not NULL, but no other checks for now
	*
	* @dev Device to check
	* @return parent's platform data, or NULL if none
	*/
	void dev_get_parent_platdata(struct udevice dev);

	/**
	* dev_get_uclass_platdata() - Get the uclass platform data for a device
	*
	* This checks that dev is not NULL, but no other checks for now
	*
	* @dev Device to check
	* @return uclass's platform data, or NULL if none
	*/
	void dev_get_uclass_platdata(struct udevice dev);

	/**
	* dev_get_parentdata() - Get the parent data for a device
	*
	* The parent data is data stored in the device but owned by the parent.
	* For example, a USB device may have parent data which contains information
	* about how to talk to the device over USB.
	*
	* This checks that dev is not NULL, but no other checks for now
	*
	* @dev Device to check
	* @return parent data, or NULL if none
	*/
	void dev_get_parentdata(struct udevice dev);

	/**
	* dev_get_priv() - Get the private data for a device
	*
	* This checks that dev is not NULL, but no other checks for now
	*
	* @dev Device to check
	* @return private data, or NULL if none
	*/
	void dev_get_priv(struct udevice dev);

	/**
	* struct dev_get_parent() - Get the parent of a device
	*
	* @child: Child to check
	* @return parent of child, or NULL if this is the root device
	*/
	struct udevice dev_get_parent(struct udevice child);

	/**
	* dev_get_uclass_priv() - Get the private uclass data for a device
	*
	* This checks that dev is not NULL, but no other checks for now
	*
	* @dev Device to check
	* @return private uclass data for this device, or NULL if none
	*/
	void dev_get_uclass_priv(struct udevice dev);

	/**
	* dev_get_driver_data() - get the driver data used to bind a device
	*
	* When a device is bound using a device tree node, it matches a
	* particular compatible string as in struct udevice_id. This function
	* returns the associated data value for that compatible string. This is
	* the 'data' field in struct udevice_id.
	*
	* For USB devices, this is the driver_info field in struct usb_device_id.
	*
	* @dev: Device to check
	*/
	ulong dev_get_driver_data(struct udevice *dev);

	/**
	* dev_get_driver_ops() - get the device's driver's operations
	*
	* This checks that dev is not NULL, and returns the pointer to device's
	* driver's operations.
	*
	* @dev: Device to check
	* @return void pointer to driver's operations or NULL for NULL-dev or NULL-ops
	*/
	const void dev_get_driver_ops(struct udevice dev);

	/*
	* device_get_uclass_id() - return the uclass ID of a device
	*
	* @dev: Device to check
	* @return uclass ID for the device
	*/
	enum uclass_id device_get_uclass_id(struct udevice *dev);

	/*
	* dev_get_uclass_name() - return the uclass name of a device
	*
	* This checks that dev is not NULL.
	*
	* @dev: Device to check
	* @return pointer to the uclass name for the device
	*/
	const char dev_get_uclass_name(struct udevice dev);

	/**
	* device_get_child() - Get the child of a device by index
	*
	* Returns the numbered child, 0 being the first. This does not use
	* sequence numbers, only the natural order.
	*
	* @dev: Parent device to check
	* @index: Child index
	* @devp: Returns pointer to device
	* @return 0 if OK, -ENODEV if no such device, other error if the device fails
	* to probe
	*/
	int device_get_child(struct udevice parent, int index, struct udevice *devp);

	/**
	* device_find_child_by_seq() - Find a child device based on a sequence
	*
	* This searches for a device with the given seq or req_seq.
	*
	* For seq, if an active device has this sequence it will be returned.
	* If there is no such device then this will return -ENODEV.
	*
	* For req_seq, if a device (whether activated or not) has this req_seq
	* value, that device will be returned. This is a strong indication that
	* the device will receive that sequence when activated.
	*
	* @parent: Parent device
	* @seq_or_req_seq: Sequence number to find (0=first)
	* @find_req_seq: true to find req_seq, false to find seq
	* @devp: Returns pointer to device (there is only one per for each seq).
	* Set to NULL if none is found
	* @return 0 if OK, -ve on error
	*/
	int device_find_child_by_seq(struct udevice *parent, int seq_or_req_seq,
	bool find_req_seq, struct udevice **devp);

	/**
	* device_get_child_by_seq() - Get a child device based on a 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.
	*
	* @parent: Parent device
	* @seq: Sequence number to find (0=first)
	* @devp: Returns pointer to device (there is only one per for each seq)
	* Set to NULL if none is found
	* @return 0 if OK, -ve on error
	*/
	int device_get_child_by_seq(struct udevice *parent, int seq,
	struct udevice **devp);

	/**
	* device_find_child_by_of_offset() - Find a child device based on FDT offset
	*
	* Locates a child device by its device tree offset.
	*
	* @parent: Parent device
	* @of_offset: Device tree offset to find
	* @devp: Returns pointer to device if found, otherwise this is set to NULL
	* @return 0 if OK, -ve on error
	*/
	int device_find_child_by_of_offset(struct udevice *parent, int of_offset,
	struct udevice **devp);

	/**
	* device_get_child_by_of_offset() - Get a child device based on FDT offset
	*
	* Locates a child device by its device tree offset.
	*
	* The device is probed to activate it ready for use.
	*
	* @parent: Parent device
	* @of_offset: Device tree offset to find
	* @devp: Returns pointer to device if found, otherwise this is set to NULL
	* @return 0 if OK, -ve on error
	*/
	int device_get_child_by_of_offset(struct udevice *parent, int of_offset,
	struct udevice **devp);

	/**
	* device_get_global_by_of_offset() - Get a device based on FDT offset
	*
	* Locates a device by its device tree offset, searching globally throughout
	* the all driver model devices.
	*
	* The device is probed to activate it ready for use.
	*
	* @of_offset: Device tree offset to find
	* @devp: Returns pointer to device if found, otherwise this is set to NULL
	* @return 0 if OK, -ve on error
	*/
	int device_get_global_by_of_offset(int of_offset, struct udevice **devp);

	/**
	* device_find_first_child() - Find the first child of a device
	*
	* @parent: Parent device to search
	* @devp: Returns first child device, or NULL if none
	* @return 0
	*/
	int device_find_first_child(struct udevice parent, struct udevice *devp);

	/**
	* device_find_next_child() - Find the next child of a device
	*
	* @devp: Pointer to previous child device on entry. Returns pointer to next
	* child device, or NULL if none
	* @return 0
	*/
	int device_find_next_child(struct udevice **devp);

	/**
	* dev_get_addr() - Get the reg property of a device
	*
	* @dev: Pointer to a device
	*
	* @return addr
	*/
	fdt_addr_t dev_get_addr(struct udevice *dev);

	/**
	* device_has_children() - check if a device has any children
	*
	* @dev: Device to check
	* @return true if the device has one or more children
	*/
	bool device_has_children(struct udevice *dev);

	/**
	* device_has_active_children() - check if a device has any active children
	*
	* @dev: Device to check
	* @return true if the device has one or more children and at least one of
	* them is active (probed).
	*/
	bool device_has_active_children(struct udevice *dev);

	/**
	* device_is_last_sibling() - check if a device is the last sibling
	*
	* This function can be useful for display purposes, when special action needs
	* to be taken when displaying the last sibling. This can happen when a tree
	* view of devices is being displayed.
	*
	* @dev: Device to check
	* @return true if there are no more siblings after this one - i.e. is it
	* last in the list.
	*/
	bool device_is_last_sibling(struct udevice *dev);

	/* device resource management */
	typedef void (dr_release_t)(struct udevice dev, void *res);
	typedef int (dr_match_t)(struct udevice dev, void res, void match_data);

	#ifdef CONFIG_DEBUG_DEVRES
	void *__devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
	const char *name);
	#define _devres_alloc(release, size, gfp) \
	__devres_alloc(release, size, gfp, #release)
	#else
	void *_devres_alloc(dr_release_t release, size_t size, gfp_t gfp);
	#endif

	/**
	* devres_alloc - Allocate device resource data
	* @release: Release function devres will be associated with
	* @size: Allocation size
	* @gfp: Allocation flags
	*
	* Allocate devres of @size bytes. The allocated area is associated
	* with @release. The returned pointer can be passed to
	* other devres_*() functions.
	*
	* RETURNS:
	* Pointer to allocated devres on success, NULL on failure.
	*/
	#define devres_alloc(release, size, gfp) \
	_devres_alloc(release, size, gfp \| __GFP_ZERO)

	/**
	* devres_free - Free device resource data
	* @res: Pointer to devres data to free
	*
	* Free devres created with devres_alloc().
	*/
	void devres_free(void *res);

	/**
	* devres_add - Register device resource
	* @dev: Device to add resource to
	* @res: Resource to register
	*
	* Register devres @res to @dev. @res should have been allocated
	* using devres_alloc(). On driver detach, the associated release
	* function will be invoked and devres will be freed automatically.
	*/
	void devres_add(struct udevice dev, void res);

	/**
	* devres_find - Find device resource
	* @dev: Device to lookup resource from
	* @release: Look for resources associated with this release function
	* @match: Match function (optional)
	* @match_data: Data for the match function
	*
	* Find the latest devres of @dev which is associated with @release
	* and for which @match returns 1. If @match is NULL, it's considered
	* to match all.
	*
	* RETURNS:
	* Pointer to found devres, NULL if not found.
	*/
	void devres_find(struct udevice dev, dr_release_t release,
	dr_match_t match, void *match_data);

	/**
	* devres_get - Find devres, if non-existent, add one atomically
	* @dev: Device to lookup or add devres for
	* @new_res: Pointer to new initialized devres to add if not found
	* @match: Match function (optional)
	* @match_data: Data for the match function
	*
	* Find the latest devres of @dev which has the same release function
	* as @new_res and for which @match return 1. If found, @new_res is
	* freed; otherwise, @new_res is added atomically.
	*
	* RETURNS:
	* Pointer to found or added devres.
	*/
	void devres_get(struct udevice dev, void *new_res,
	dr_match_t match, void *match_data);

	/**
	* devres_remove - Find a device resource and remove it
	* @dev: Device to find resource from
	* @release: Look for resources associated with this release function
	* @match: Match function (optional)
	* @match_data: Data for the match function
	*
	* Find the latest devres of @dev associated with @release and for
	* which @match returns 1. If @match is NULL, it's considered to
	* match all. If found, the resource is removed atomically and
	* returned.
	*
	* RETURNS:
	* Pointer to removed devres on success, NULL if not found.
	*/
	void devres_remove(struct udevice dev, dr_release_t release,
	dr_match_t match, void *match_data);

	/**
	* devres_destroy - Find a device resource and destroy it
	* @dev: Device to find resource from
	* @release: Look for resources associated with this release function
	* @match: Match function (optional)
	* @match_data: Data for the match function
	*
	* Find the latest devres of @dev associated with @release and for
	* which @match returns 1. If @match is NULL, it's considered to
	* match all. If found, the resource is removed atomically and freed.
	*
	* Note that the release function for the resource will not be called,
	* only the devres-allocated data will be freed. The caller becomes
	* responsible for freeing any other data.
	*
	* RETURNS:
	* 0 if devres is found and freed, -ENOENT if not found.
	*/
	int devres_destroy(struct udevice *dev, dr_release_t release,
	dr_match_t match, void *match_data);

	/**
	* devres_release - Find a device resource and destroy it, calling release
	* @dev: Device to find resource from
	* @release: Look for resources associated with this release function
	* @match: Match function (optional)
	* @match_data: Data for the match function
	*
	* Find the latest devres of @dev associated with @release and for
	* which @match returns 1. If @match is NULL, it's considered to
	* match all. If found, the resource is removed atomically, the
	* release function called and the resource freed.
	*
	* RETURNS:
	* 0 if devres is found and freed, -ENOENT if not found.
	*/
	int devres_release(struct udevice *dev, dr_release_t release,
	dr_match_t match, void *match_data);

	#endif