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 * @init: Called to set up the uclass 59 * @destroy: Called to destroy the uclass 60 * @priv_auto_alloc_size: If non-zero this is the size of the private data 61 * to be allocated in the uclass's ->priv pointer. If zero, then the uclass 62 * driver is responsible for allocating any data required. 63 * @per_device_auto_alloc_size: Each device can hold private data owned 64 * by the uclass. If required this will be automatically allocated if this 65 * value is non-zero. 66 * @per_child_platdata_auto_alloc_size: A bus likes to store information about 67 * its children. If non-zero this is the size of this data, to be allocated 68 * in the child device's parent_platdata pointer. This value is only used as 69 * a falback if this member is 0 in the driver. 70 * @ops: Uclass operations, providing the consistent interface to devices 71 * within the uclass. 72 * @flags: Flags for this uclass (DM_UC_...) 73 */ 74 struct uclass_driver { 75 const char *name; 76 enum uclass_id id; 77 int (*post_bind)(struct udevice *dev); 78 int (*pre_unbind)(struct udevice *dev); 79 int (*post_probe)(struct udevice *dev); 80 int (*pre_remove)(struct udevice *dev); 81 int (*init)(struct uclass *class); 82 int (*destroy)(struct uclass *class); 83 int priv_auto_alloc_size; 84 int per_device_auto_alloc_size; 85 int per_child_platdata_auto_alloc_size; 86 const void *ops; 87 uint32_t flags; 88 }; 89 90 /* Declare a new uclass_driver */ 91 #define UCLASS_DRIVER(__name) \ 92 ll_entry_declare(struct uclass_driver, __name, uclass) 93 94 /** 95 * uclass_get() - Get a uclass based on an ID, creating it if needed 96 * 97 * Every uclass is identified by an ID, a number from 0 to n-1 where n is 98 * the number of uclasses. This function allows looking up a uclass by its 99 * ID. 100 * 101 * @key: ID to look up 102 * @ucp: Returns pointer to uclass (there is only one per ID) 103 * @return 0 if OK, -ve on error 104 */ 105 int uclass_get(enum uclass_id key, struct uclass **ucp); 106 107 /** 108 * uclass_get_device() - Get a uclass device based on an ID and index 109 * 110 * The device is probed to activate it ready for use. 111 * 112 * @id: ID to look up 113 * @index: Device number within that uclass (0=first) 114 * @devp: Returns pointer to device (there is only one per for each ID) 115 * @return 0 if OK, -ve on error 116 */ 117 int uclass_get_device(enum uclass_id id, int index, struct udevice **devp); 118 119 /** 120 * uclass_get_device_by_seq() - Get a uclass device based on an ID and sequence 121 * 122 * If an active device has this sequence it will be returned. If there is no 123 * such device then this will check for a device that is requesting this 124 * sequence. 125 * 126 * The device is probed to activate it ready for use. 127 * 128 * @id: ID to look up 129 * @seq: Sequence number to find (0=first) 130 * @devp: Returns pointer to device (there is only one for each seq) 131 * @return 0 if OK, -ve on error 132 */ 133 int uclass_get_device_by_seq(enum uclass_id id, int seq, struct udevice **devp); 134 135 /** 136 * uclass_get_device_by_of_offset() - Get a uclass device by device tree node 137 * 138 * This searches the devices in the uclass for one attached to the given 139 * device tree node. 140 * 141 * The device is probed to activate it ready for use. 142 * 143 * @id: ID to look up 144 * @node: Device tree offset to search for (if -ve then -ENODEV is returned) 145 * @devp: Returns pointer to device (there is only one for each node) 146 * @return 0 if OK, -ve on error 147 */ 148 int uclass_get_device_by_of_offset(enum uclass_id id, int node, 149 struct udevice **devp); 150 151 /** 152 * uclass_first_device() - Get the first device in a uclass 153 * 154 * The device returned is probed if necessary, and ready for use 155 * 156 * @id: Uclass ID to look up 157 * @devp: Returns pointer to the first device in that uclass, or NULL if none 158 * @return 0 if OK (found or not found), -1 on error 159 */ 160 int uclass_first_device(enum uclass_id id, struct udevice **devp); 161 162 /** 163 * uclass_next_device() - Get the next device in a uclass 164 * 165 * The device returned is probed if necessary, and ready for use 166 * 167 * @devp: On entry, pointer to device to lookup. On exit, returns pointer 168 * to the next device in the same uclass, or NULL if none 169 * @return 0 if OK (found or not found), -1 on error 170 */ 171 int uclass_next_device(struct udevice **devp); 172 173 /** 174 * uclass_resolve_seq() - Resolve a device's sequence number 175 * 176 * On entry dev->seq is -1, and dev->req_seq may be -1 (to allocate a 177 * sequence number automatically, or >= 0 to select a particular number. 178 * If the requested sequence number is in use, then this device will 179 * be allocated another one. 180 * 181 * Note that the device's seq value is not changed by this function. 182 * 183 * @dev: Device for which to allocate sequence number 184 * @return sequence number allocated, or -ve on error 185 */ 186 int uclass_resolve_seq(struct udevice *dev); 187 188 /** 189 * uclass_foreach_dev() - Helper function to iteration through devices 190 * 191 * This creates a for() loop which works through the available devices in 192 * a uclass in order from start to end. 193 * 194 * @pos: struct udevice * to hold the current device. Set to NULL when there 195 * are no more devices. 196 * @uc: uclass to scan 197 */ 198 #define uclass_foreach_dev(pos, uc) \ 199 for (pos = list_entry((&(uc)->dev_head)->next, typeof(*pos), \ 200 uclass_node); \ 201 prefetch(pos->uclass_node.next), \ 202 &pos->uclass_node != (&(uc)->dev_head); \ 203 pos = list_entry(pos->uclass_node.next, typeof(*pos), \ 204 uclass_node)) 205 206 #endif 207