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 device; 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 device *dev); 69 int (*pre_unbind)(struct device *dev); 70 int (*post_probe)(struct device *dev); 71 int (*pre_remove)(struct device *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 * id: ID to look up 100 * @index: Device number within that uclass (0=first) 101 * @ucp: Returns pointer to uclass (there is only one per for each ID) 102 * @return 0 if OK, -ve on error 103 */ 104 int uclass_get_device(enum uclass_id id, int index, struct device **ucp); 105 106 /** 107 * uclass_first_device() - Get the first device in a uclass 108 * 109 * @id: Uclass ID to look up 110 * @devp: Returns pointer to the first device in that uclass, or NULL if none 111 * @return 0 if OK (found or not found), -1 on error 112 */ 113 int uclass_first_device(enum uclass_id id, struct device **devp); 114 115 /** 116 * uclass_next_device() - Get the next device in a uclass 117 * 118 * @devp: On entry, pointer to device to lookup. On exit, returns pointer 119 * to the next device in the same uclass, or NULL if none 120 * @return 0 if OK (found or not found), -1 on error 121 */ 122 int uclass_next_device(struct device **devp); 123 124 /** 125 * uclass_foreach_dev() - Helper function to iteration through devices 126 * 127 * This creates a for() loop which works through the available devices in 128 * a uclass in order from start to end. 129 * 130 * @pos: struct device * to hold the current device. Set to NULL when there 131 * are no more devices. 132 * uc: uclass to scan 133 */ 134 #define uclass_foreach_dev(pos, uc) \ 135 for (pos = list_entry((&(uc)->dev_head)->next, typeof(*pos), \ 136 uclass_node); \ 137 prefetch(pos->uclass_node.next), \ 138 &pos->uclass_node != (&(uc)->dev_head); \ 139 pos = list_entry(pos->uclass_node.next, typeof(*pos), \ 140 uclass_node)) 141 142 #endif 143