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 214