1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * driver.c - centralized device driver management 4 * 5 * Copyright (c) 2002-3 Patrick Mochel 6 * Copyright (c) 2002-3 Open Source Development Labs 7 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> 8 * Copyright (c) 2007 Novell Inc. 9 */ 10 11 #include <linux/device/driver.h> 12 #include <linux/device.h> 13 #include <linux/module.h> 14 #include <linux/errno.h> 15 #include <linux/slab.h> 16 #include <linux/string.h> 17 #include <linux/sysfs.h> 18 #include "base.h" 19 20 static struct device *next_device(struct klist_iter *i) 21 { 22 struct klist_node *n = klist_next(i); 23 struct device *dev = NULL; 24 struct device_private *dev_prv; 25 26 if (n) { 27 dev_prv = to_device_private_driver(n); 28 dev = dev_prv->device; 29 } 30 return dev; 31 } 32 33 /** 34 * driver_for_each_device - Iterator for devices bound to a driver. 35 * @drv: Driver we're iterating. 36 * @start: Device to begin with 37 * @data: Data to pass to the callback. 38 * @fn: Function to call for each device. 39 * 40 * Iterate over the @drv's list of devices calling @fn for each one. 41 */ 42 int driver_for_each_device(struct device_driver *drv, struct device *start, 43 void *data, device_iter_t fn) 44 { 45 struct klist_iter i; 46 struct device *dev; 47 int error = 0; 48 49 if (!drv) 50 return -EINVAL; 51 52 klist_iter_init_node(&drv->p->klist_devices, &i, 53 start ? &start->p->knode_driver : NULL); 54 while (!error && (dev = next_device(&i))) 55 error = fn(dev, data); 56 klist_iter_exit(&i); 57 return error; 58 } 59 EXPORT_SYMBOL_GPL(driver_for_each_device); 60 61 /** 62 * driver_find_device - device iterator for locating a particular device. 63 * @drv: The device's driver 64 * @start: Device to begin with 65 * @data: Data to pass to match function 66 * @match: Callback function to check device 67 * 68 * This is similar to the driver_for_each_device() function above, but 69 * it returns a reference to a device that is 'found' for later use, as 70 * determined by the @match callback. 71 * 72 * The callback should return 0 if the device doesn't match and non-zero 73 * if it does. If the callback returns non-zero, this function will 74 * return to the caller and not iterate over any more devices. 75 */ 76 struct device *driver_find_device(const struct device_driver *drv, 77 struct device *start, const void *data, 78 device_match_t match) 79 { 80 struct klist_iter i; 81 struct device *dev; 82 83 if (!drv || !drv->p) 84 return NULL; 85 86 klist_iter_init_node(&drv->p->klist_devices, &i, 87 (start ? &start->p->knode_driver : NULL)); 88 while ((dev = next_device(&i))) { 89 if (match(dev, data)) { 90 get_device(dev); 91 break; 92 } 93 } 94 klist_iter_exit(&i); 95 return dev; 96 } 97 EXPORT_SYMBOL_GPL(driver_find_device); 98 99 /** 100 * driver_create_file - create sysfs file for driver. 101 * @drv: driver. 102 * @attr: driver attribute descriptor. 103 */ 104 int driver_create_file(const struct device_driver *drv, 105 const struct driver_attribute *attr) 106 { 107 int error; 108 109 if (drv) 110 error = sysfs_create_file(&drv->p->kobj, &attr->attr); 111 else 112 error = -EINVAL; 113 return error; 114 } 115 EXPORT_SYMBOL_GPL(driver_create_file); 116 117 /** 118 * driver_remove_file - remove sysfs file for driver. 119 * @drv: driver. 120 * @attr: driver attribute descriptor. 121 */ 122 void driver_remove_file(const struct device_driver *drv, 123 const struct driver_attribute *attr) 124 { 125 if (drv) 126 sysfs_remove_file(&drv->p->kobj, &attr->attr); 127 } 128 EXPORT_SYMBOL_GPL(driver_remove_file); 129 130 int driver_add_groups(const struct device_driver *drv, 131 const struct attribute_group *const *groups) 132 { 133 return sysfs_create_groups(&drv->p->kobj, groups); 134 } 135 136 void driver_remove_groups(const struct device_driver *drv, 137 const struct attribute_group *const *groups) 138 { 139 sysfs_remove_groups(&drv->p->kobj, groups); 140 } 141 142 /** 143 * driver_register - register driver with bus 144 * @drv: driver to register 145 * 146 * We pass off most of the work to the bus_add_driver() call, 147 * since most of the things we have to do deal with the bus 148 * structures. 149 */ 150 int driver_register(struct device_driver *drv) 151 { 152 int ret; 153 struct device_driver *other; 154 155 if (!bus_is_registered(drv->bus)) { 156 pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n", 157 drv->name, drv->bus->name); 158 return -EINVAL; 159 } 160 161 if ((drv->bus->probe && drv->probe) || 162 (drv->bus->remove && drv->remove) || 163 (drv->bus->shutdown && drv->shutdown)) 164 pr_warn("Driver '%s' needs updating - please use " 165 "bus_type methods\n", drv->name); 166 167 other = driver_find(drv->name, drv->bus); 168 if (other) { 169 pr_err("Error: Driver '%s' is already registered, " 170 "aborting...\n", drv->name); 171 return -EBUSY; 172 } 173 174 ret = bus_add_driver(drv); 175 if (ret) 176 return ret; 177 ret = driver_add_groups(drv, drv->groups); 178 if (ret) { 179 bus_remove_driver(drv); 180 return ret; 181 } 182 kobject_uevent(&drv->p->kobj, KOBJ_ADD); 183 deferred_probe_extend_timeout(); 184 185 return ret; 186 } 187 EXPORT_SYMBOL_GPL(driver_register); 188 189 /** 190 * driver_unregister - remove driver from system. 191 * @drv: driver. 192 * 193 * Again, we pass off most of the work to the bus-level call. 194 */ 195 void driver_unregister(struct device_driver *drv) 196 { 197 if (!drv || !drv->p) { 198 WARN(1, "Unexpected driver unregister!\n"); 199 return; 200 } 201 driver_remove_groups(drv, drv->groups); 202 bus_remove_driver(drv); 203 } 204 EXPORT_SYMBOL_GPL(driver_unregister); 205