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_auto_alloc_size: Each child device (of a parent in this 67 * uclass) can hold parent data for the device/uclass. This value is only 68 * used as a falback if this member is 0 in the driver. 69 * @per_child_platdata_auto_alloc_size: A bus likes to store information about 70 * its children. If non-zero this is the size of this data, to be allocated 71 * in the child device's parent_platdata pointer. This value is only used as 72 * a falback if this member is 0 in the driver. 73 * @ops: Uclass operations, providing the consistent interface to devices 74 * within the uclass. 75 * @flags: Flags for this uclass (DM_UC_...) 76 */ 77 struct uclass_driver { 78 const char *name; 79 enum uclass_id id; 80 int (*post_bind)(struct udevice *dev); 81 int (*pre_unbind)(struct udevice *dev); 82 int (*post_probe)(struct udevice *dev); 83 int (*pre_remove)(struct udevice *dev); 84 int (*init)(struct uclass *class); 85 int (*destroy)(struct uclass *class); 86 int priv_auto_alloc_size; 87 int per_device_auto_alloc_size; 88 int per_child_auto_alloc_size; 89 int per_child_platdata_auto_alloc_size; 90 const void *ops; 91 uint32_t flags; 92 }; 93 94 /* Declare a new uclass_driver */ 95 #define UCLASS_DRIVER(__name) \ 96 ll_entry_declare(struct uclass_driver, __name, uclass) 97 98 /** 99 * uclass_get() - Get a uclass based on an ID, creating it if needed 100 * 101 * Every uclass is identified by an ID, a number from 0 to n-1 where n is 102 * the number of uclasses. This function allows looking up a uclass by its 103 * ID. 104 * 105 * @key: ID to look up 106 * @ucp: Returns pointer to uclass (there is only one per ID) 107 * @return 0 if OK, -ve on error 108 */ 109 int uclass_get(enum uclass_id key, struct uclass **ucp); 110 111 /** 112 * uclass_get_device() - Get a uclass device based on an ID and index 113 * 114 * The device is probed to activate it ready for use. 115 * 116 * @id: ID to look up 117 * @index: Device number within that uclass (0=first) 118 * @devp: Returns pointer to device (there is only one per for each ID) 119 * @return 0 if OK, -ve on error 120 */ 121 int uclass_get_device(enum uclass_id id, int index, struct udevice **devp); 122 123 /** 124 * uclass_get_device_by_seq() - Get a uclass device based on an ID and sequence 125 * 126 * If an active device has this sequence it will be returned. If there is no 127 * such device then this will check for a device that is requesting this 128 * sequence. 129 * 130 * The device is probed to activate it ready for use. 131 * 132 * @id: ID to look up 133 * @seq: Sequence number to find (0=first) 134 * @devp: Returns pointer to device (there is only one for each seq) 135 * @return 0 if OK, -ve on error 136 */ 137 int uclass_get_device_by_seq(enum uclass_id id, int seq, struct udevice **devp); 138 139 /** 140 * uclass_get_device_by_of_offset() - Get a uclass device by device tree node 141 * 142 * This searches the devices in the uclass for one attached to the given 143 * device tree node. 144 * 145 * The device is probed to activate it ready for use. 146 * 147 * @id: ID to look up 148 * @node: Device tree offset to search for (if -ve then -ENODEV is returned) 149 * @devp: Returns pointer to device (there is only one for each node) 150 * @return 0 if OK, -ve on error 151 */ 152 int uclass_get_device_by_of_offset(enum uclass_id id, int node, 153 struct udevice **devp); 154 155 /** 156 * uclass_first_device() - Get the first device in a uclass 157 * 158 * The device returned is probed if necessary, and ready for use 159 * 160 * @id: Uclass ID to look up 161 * @devp: Returns pointer to the first device in that uclass, or NULL if none 162 * @return 0 if OK (found or not found), -1 on error 163 */ 164 int uclass_first_device(enum uclass_id id, struct udevice **devp); 165 166 /** 167 * uclass_next_device() - Get the next device in a uclass 168 * 169 * The device returned is probed if necessary, and ready for use 170 * 171 * @devp: On entry, pointer to device to lookup. On exit, returns pointer 172 * to the next device in the same uclass, or NULL if none 173 * @return 0 if OK (found or not found), -1 on error 174 */ 175 int uclass_next_device(struct udevice **devp); 176 177 /** 178 * uclass_resolve_seq() - Resolve a device's sequence number 179 * 180 * On entry dev->seq is -1, and dev->req_seq may be -1 (to allocate a 181 * sequence number automatically, or >= 0 to select a particular number. 182 * If the requested sequence number is in use, then this device will 183 * be allocated another one. 184 * 185 * Note that the device's seq value is not changed by this function. 186 * 187 * @dev: Device for which to allocate sequence number 188 * @return sequence number allocated, or -ve on error 189 */ 190 int uclass_resolve_seq(struct udevice *dev); 191 192 /** 193 * uclass_foreach_dev() - Helper function to iteration through devices 194 * 195 * This creates a for() loop which works through the available devices in 196 * a uclass in order from start to end. 197 * 198 * @pos: struct udevice * to hold the current device. Set to NULL when there 199 * are no more devices. 200 * @uc: uclass to scan 201 */ 202 #define uclass_foreach_dev(pos, uc) \ 203 for (pos = list_entry((&(uc)->dev_head)->next, typeof(*pos), \ 204 uclass_node); \ 205 prefetch(pos->uclass_node.next), \ 206 &pos->uclass_node != (&(uc)->dev_head); \ 207 pos = list_entry(pos->uclass_node.next, typeof(*pos), \ 208 uclass_node)) 209 210 #endif 211