include/dm/uclass.h

   1 /*
   2  * Copyright (c) 2013 Google, Inc
   3  *
   4  * (C) Copyright 2012
   5  * Pavel Herrmann <morpheus.ibis@gmail.com>
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 #ifndef _DM_UCLASS_H
  11 #define _DM_UCLASS_H
  12
  13 #include <dm/uclass-id.h>
  14 #include <linker_lists.h>
  15 #include <linux/list.h>
  16
  17 /**
  18  * struct uclass - a U-Boot drive class, collecting together similar drivers
  19  *
  20  * A uclass provides an interface to a particular function, which is
  21  * implemented by one or more drivers. Every driver belongs to a uclass even
  22  * if it is the only driver in that uclass. An example uclass is GPIO, which
  23  * provides the ability to change read inputs, set and clear outputs, etc.
  24  * There may be drivers for on-chip SoC GPIO banks, I2C GPIO expanders and
  25  * PMIC IO lines, all made available in a unified way through the uclass.
  26  *
  27  * @priv: Private data for this uclass
  28  * @uc_drv: The driver for the uclass itself, not to be confused with a
  29  * 'struct driver'
  30  * @dev_head: List of devices in this uclass (devices are attached to their
  31  * uclass when their bind method is called)
  32  * @sibling_node: Next uclass in the linked list of uclasses
  33  */
  34 struct uclass {
  35         void *priv;
  36         struct uclass_driver *uc_drv;
  37         struct list_head dev_head;
  38         struct list_head sibling_node;
  39 };
  40
  41 struct udevice;
  42
  43 /* Members of this uclass sequence themselves with aliases */
  44 #define DM_UC_FLAG_SEQ_ALIAS                    (1 << 0)
  45
  46 /**
  47  * struct uclass_driver - Driver for the uclass
  48  *
  49  * A uclass_driver provides a consistent interface to a set of related
  50  * drivers.
  51  *
  52  * @name: Name of uclass driver
  53  * @id: ID number of this uclass
  54  * @post_bind: Called after a new device is bound to this uclass
  55  * @pre_unbind: Called before a device is unbound from this uclass
  56  * @post_probe: Called after a new device is probed
  57  * @pre_remove: Called before a device is removed
  58  * @child_post_bind: Called after a child is bound to a device in this uclass
  59  * @init: Called to set up the uclass
  60  * @destroy: Called to destroy the uclass
  61  * @priv_auto_alloc_size: If non-zero this is the size of the private data
  62  * to be allocated in the uclass's ->priv pointer. If zero, then the uclass
  63  * driver is responsible for allocating any data required.
  64  * @per_device_auto_alloc_size: Each device can hold private data owned
  65  * by the uclass. If required this will be automatically allocated if this
  66  * value is non-zero.
  67  * @per_child_auto_alloc_size: Each child device (of a parent in this
  68  * uclass) can hold parent data for the device/uclass. This value is only
  69  * used as a falback if this member is 0 in the driver.
  70  * @per_child_platdata_auto_alloc_size: A bus likes to store information about
  71  * its children. If non-zero this is the size of this data, to be allocated
  72  * in the child device's parent_platdata pointer. This value is only used as
  73  * a falback if this member is 0 in the driver.
  74  * @ops: Uclass operations, providing the consistent interface to devices
  75  * within the uclass.
  76  * @flags: Flags for this uclass (DM_UC_...)
  77  */
  78 struct uclass_driver {
  79         const char *name;
  80         enum uclass_id id;
  81         int (*post_bind)(struct udevice *dev);
  82         int (*pre_unbind)(struct udevice *dev);
  83         int (*post_probe)(struct udevice *dev);
  84         int (*pre_remove)(struct udevice *dev);
  85         int (*child_post_bind)(struct udevice *dev);
  86         int (*child_pre_probe)(struct udevice *dev);
  87         int (*init)(struct uclass *class);
  88         int (*destroy)(struct uclass *class);
  89         int priv_auto_alloc_size;
  90         int per_device_auto_alloc_size;
  91         int per_child_auto_alloc_size;
  92         int per_child_platdata_auto_alloc_size;
  93         const void *ops;
  94         uint32_t flags;
  95 };
  96
  97 /* Declare a new uclass_driver */
  98 #define UCLASS_DRIVER(__name)                                           \
  99         ll_entry_declare(struct uclass_driver, __name, uclass)
 100
 101 /**
 102  * uclass_get() - Get a uclass based on an ID, creating it if needed
 103  *
 104  * Every uclass is identified by an ID, a number from 0 to n-1 where n is
 105  * the number of uclasses. This function allows looking up a uclass by its
 106  * ID.
 107  *
 108  * @key: ID to look up
 109  * @ucp: Returns pointer to uclass (there is only one per ID)
 110  * @return 0 if OK, -ve on error
 111  */
 112 int uclass_get(enum uclass_id key, struct uclass **ucp);
 113
 114 /**
 115  * uclass_get_device() - Get a uclass device based on an ID and index
 116  *
 117  * The device is probed to activate it ready for use.
 118  *
 119  * @id: ID to look up
 120  * @index: Device number within that uclass (0=first)
 121  * @devp: Returns pointer to device (there is only one per for each ID)
 122  * @return 0 if OK, -ve on error
 123  */
 124 int uclass_get_device(enum uclass_id id, int index, struct udevice **devp);
 125
 126 /**
 127  * uclass_get_device_by_seq() - Get a uclass device based on an ID and sequence
 128  *
 129  * If an active device has this sequence it will be returned. If there is no
 130  * such device then this will check for a device that is requesting this
 131  * sequence.
 132  *
 133  * The device is probed to activate it ready for use.
 134  *
 135  * @id: ID to look up
 136  * @seq: Sequence number to find (0=first)
 137  * @devp: Returns pointer to device (there is only one for each seq)
 138  * @return 0 if OK, -ve on error
 139  */
 140 int uclass_get_device_by_seq(enum uclass_id id, int seq, struct udevice **devp);
 141
 142 /**
 143  * uclass_get_device_by_of_offset() - Get a uclass device by device tree node
 144  *
 145  * This searches the devices in the uclass for one attached to the given
 146  * device tree node.
 147  *
 148  * The device is probed to activate it ready for use.
 149  *
 150  * @id: ID to look up
 151  * @node: Device tree offset to search for (if -ve then -ENODEV is returned)
 152  * @devp: Returns pointer to device (there is only one for each node)
 153  * @return 0 if OK, -ve on error
 154  */
 155 int uclass_get_device_by_of_offset(enum uclass_id id, int node,
 156                                    struct udevice **devp);
 157
 158 /**
 159  * uclass_first_device() - Get the first device in a uclass
 160  *
 161  * The device returned is probed if necessary, and ready for use
 162  *
 163  * @id: Uclass ID to look up
 164  * @devp: Returns pointer to the first device in that uclass, or NULL if none
 165  * @return 0 if OK (found or not found), -1 on error
 166  */
 167 int uclass_first_device(enum uclass_id id, struct udevice **devp);
 168
 169 /**
 170  * uclass_next_device() - Get the next device in a uclass
 171  *
 172  * The device returned is probed if necessary, and ready for use
 173  *
 174  * @devp: On entry, pointer to device to lookup. On exit, returns pointer
 175  * to the next device in the same uclass, or NULL if none
 176  * @return 0 if OK (found or not found), -1 on error
 177  */
 178 int uclass_next_device(struct udevice **devp);
 179
 180 /**
 181  * uclass_resolve_seq() - Resolve a device's sequence number
 182  *
 183  * On entry dev->seq is -1, and dev->req_seq may be -1 (to allocate a
 184  * sequence number automatically, or >= 0 to select a particular number.
 185  * If the requested sequence number is in use, then this device will
 186  * be allocated another one.
 187  *
 188  * Note that the device's seq value is not changed by this function.
 189  *
 190  * @dev: Device for which to allocate sequence number
 191  * @return sequence number allocated, or -ve on error
 192  */
 193 int uclass_resolve_seq(struct udevice *dev);
 194
 195 /**
 196  * uclass_foreach_dev() - Helper function to iteration through devices
 197  *
 198  * This creates a for() loop which works through the available devices in
 199  * a uclass in order from start to end.
 200  *
 201  * @pos: struct udevice * to hold the current device. Set to NULL when there
 202  * are no more devices.
 203  * @uc: uclass to scan
 204  */
 205 #define uclass_foreach_dev(pos, uc)                                     \
 206         for (pos = list_entry((&(uc)->dev_head)->next, typeof(*pos),    \
 207                         uclass_node);                                   \
 208              prefetch(pos->uclass_node.next),                           \
 209                         &pos->uclass_node != (&(uc)->dev_head);         \
 210              pos = list_entry(pos->uclass_node.next, typeof(*pos),      \
 211                         uclass_node))
 212
 213 #endif