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