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 /** 44 * struct uclass_driver - Driver for the uclass 45 * 46 * A uclass_driver provides a consistent interface to a set of related 47 * drivers. 48 * 49 * @name: Name of uclass driver 50 * @id: ID number of this uclass 51 * @post_bind: Called after a new device is bound to this uclass 52 * @pre_unbind: Called before a device is unbound from this uclass 53 * @post_probe: Called after a new device is probed 54 * @pre_remove: Called before a device is removed 55 * @init: Called to set up the uclass 56 * @destroy: Called to destroy the uclass 57 * @priv_auto_alloc_size: If non-zero this is the size of the private data 58 * to be allocated in the uclass's ->priv pointer. If zero, then the uclass 59 * driver is responsible for allocating any data required. 60 * @per_device_auto_alloc_size: Each device can hold private data owned 61 * by the uclass. If required this will be automatically allocated if this 62 * value is non-zero. 63 * @ops: Uclass operations, providing the consistent interface to devices 64 * within the uclass. 65 */ 66 struct uclass_driver { 67 const char *name; 68 enum uclass_id id; 69 int (*post_bind)(struct udevice *dev); 70 int (*pre_unbind)(struct udevice *dev); 71 int (*post_probe)(struct udevice *dev); 72 int (*pre_remove)(struct udevice *dev); 73 int (*init)(struct uclass *class); 74 int (*destroy)(struct uclass *class); 75 int priv_auto_alloc_size; 76 int per_device_auto_alloc_size; 77 const void *ops; 78 }; 79 80 /* Declare a new uclass_driver */ 81 #define UCLASS_DRIVER(__name) \ 82 ll_entry_declare(struct uclass_driver, __name, uclass) 83 84 /** 85 * uclass_get() - Get a uclass based on an ID, creating it if needed 86 * 87 * Every uclass is identified by an ID, a number from 0 to n-1 where n is 88 * the number of uclasses. This function allows looking up a uclass by its 89 * ID. 90 * 91 * @key: ID to look up 92 * @ucp: Returns pointer to uclass (there is only one per ID) 93 * @return 0 if OK, -ve on error 94 */ 95 int uclass_get(enum uclass_id key, struct uclass **ucp); 96 97 /** 98 * uclass_get_device() - Get a uclass device based on an ID and index 99 * 100 * The device is probed to activate it ready for use. 101 * 102 * @id: ID to look up 103 * @index: Device number within that uclass (0=first) 104 * @devp: Returns pointer to device (there is only one per for each ID) 105 * @return 0 if OK, -ve on error 106 */ 107 int uclass_get_device(enum uclass_id id, int index, struct udevice **devp); 108 109 /** 110 * uclass_get_device_by_seq() - Get a uclass device based on an ID and sequence 111 * 112 * If an active device has this sequence it will be returned. If there is no 113 * such device then this will check for a device that is requesting this 114 * sequence. 115 * 116 * The device is probed to activate it ready for use. 117 * 118 * @id: ID to look up 119 * @seq: Sequence number to find (0=first) 120 * @devp: Returns pointer to device (there is only one for each seq) 121 * @return 0 if OK, -ve on error 122 */ 123 int uclass_get_device_by_seq(enum uclass_id id, int seq, struct udevice **devp); 124 125 /** 126 * uclass_get_device_by_of_offset() - Get a uclass device by device tree node 127 * 128 * This searches the devices in the uclass for one attached to the given 129 * device tree node. 130 * 131 * The device is probed to activate it ready for use. 132 * 133 * @id: ID to look up 134 * @node: Device tree offset to search for (if -ve then -ENODEV is returned) 135 * @devp: Returns pointer to device (there is only one for each node) 136 * @return 0 if OK, -ve on error 137 */ 138 int uclass_get_device_by_of_offset(enum uclass_id id, int node, 139 struct udevice **devp); 140 141 /** 142 * uclass_first_device() - Get the first device in a uclass 143 * 144 * @id: Uclass ID to look up 145 * @devp: Returns pointer to the first device in that uclass, or NULL if none 146 * @return 0 if OK (found or not found), -1 on error 147 */ 148 int uclass_first_device(enum uclass_id id, struct udevice **devp); 149 150 /** 151 * uclass_next_device() - Get the next device in a uclass 152 * 153 * @devp: On entry, pointer to device to lookup. On exit, returns pointer 154 * to the next device in the same uclass, or NULL if none 155 * @return 0 if OK (found or not found), -1 on error 156 */ 157 int uclass_next_device(struct udevice **devp); 158 159 /** 160 * uclass_resolve_seq() - Resolve a device's sequence number 161 * 162 * On entry dev->seq is -1, and dev->req_seq may be -1 (to allocate a 163 * sequence number automatically, or >= 0 to select a particular number. 164 * If the requested sequence number is in use, then this device will 165 * be allocated another one. 166 * 167 * Note that the device's seq value is not changed by this function. 168 * 169 * @dev: Device for which to allocate sequence number 170 * @return sequence number allocated, or -ve on error 171 */ 172 int uclass_resolve_seq(struct udevice *dev); 173 174 /** 175 * uclass_foreach_dev() - Helper function to iteration through devices 176 * 177 * This creates a for() loop which works through the available devices in 178 * a uclass in order from start to end. 179 * 180 * @pos: struct udevice * to hold the current device. Set to NULL when there 181 * are no more devices. 182 * @uc: uclass to scan 183 */ 184 #define uclass_foreach_dev(pos, uc) \ 185 for (pos = list_entry((&(uc)->dev_head)->next, typeof(*pos), \ 186 uclass_node); \ 187 prefetch(pos->uclass_node.next), \ 188 &pos->uclass_node != (&(uc)->dev_head); \ 189 pos = list_entry(pos->uclass_node.next, typeof(*pos), \ 190 uclass_node)) 191 192 #endif 193