2 * driver.c - centralized device driver management
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
7 * This file is released under the GPLv2
11 #include <linux/config.h>
12 #include <linux/device.h>
13 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/string.h>
18 #define to_dev(node) container_of(node, struct device, driver_list)
19 #define to_drv(obj) container_of(obj, struct device_driver, kobj)
22 static struct device * next_device(struct klist_iter * i)
24 struct klist_node * n = klist_next(i);
25 return n ? container_of(n, struct device, knode_driver) : NULL;
29 * driver_for_each_device - Iterator for devices bound to a driver.
30 * @drv: Driver we're iterating.
31 * @data: Data to pass to the callback.
32 * @fn: Function to call for each device.
34 * Take the bus's rwsem and iterate over the @drv's list of devices,
35 * calling @fn for each one.
38 int driver_for_each_device(struct device_driver * drv, struct device * start,
39 void * data, int (*fn)(struct device *, void *))
48 klist_iter_init_node(&drv->klist_devices, &i,
49 start ? &start->knode_driver : NULL);
50 while ((dev = next_device(&i)) && !error)
51 error = fn(dev, data);
56 EXPORT_SYMBOL(driver_for_each_device);
60 * driver_create_file - create sysfs file for driver.
62 * @attr: driver attribute descriptor.
65 int driver_create_file(struct device_driver * drv, struct driver_attribute * attr)
68 if (get_driver(drv)) {
69 error = sysfs_create_file(&drv->kobj, &attr->attr);
78 * driver_remove_file - remove sysfs file for driver.
80 * @attr: driver attribute descriptor.
83 void driver_remove_file(struct device_driver * drv, struct driver_attribute * attr)
85 if (get_driver(drv)) {
86 sysfs_remove_file(&drv->kobj, &attr->attr);
93 * get_driver - increment driver reference count.
96 struct device_driver * get_driver(struct device_driver * drv)
98 return drv ? to_drv(kobject_get(&drv->kobj)) : NULL;
103 * put_driver - decrement driver's refcount.
106 void put_driver(struct device_driver * drv)
108 kobject_put(&drv->kobj);
113 * driver_register - register driver with bus
114 * @drv: driver to register
116 * We pass off most of the work to the bus_add_driver() call,
117 * since most of the things we have to do deal with the bus
120 * The one interesting aspect is that we setup @drv->unloaded
121 * as a completion that gets complete when the driver reference
124 int driver_register(struct device_driver * drv)
126 klist_init(&drv->klist_devices);
127 init_completion(&drv->unloaded);
128 return bus_add_driver(drv);
133 * driver_unregister - remove driver from system.
136 * Again, we pass off most of the work to the bus-level call.
138 * Though, once that is done, we wait until @drv->unloaded is completed.
139 * This will block until the driver refcount reaches 0, and it is
140 * released. Only modular drivers will call this function, and we
141 * have to guarantee that it won't complete, letting the driver
142 * unload until all references are gone.
145 void driver_unregister(struct device_driver * drv)
147 bus_remove_driver(drv);
148 wait_for_completion(&drv->unloaded);
152 * driver_find - locate driver on a bus by its name.
153 * @name: name of the driver.
154 * @bus: bus to scan for the driver.
156 * Call kset_find_obj() to iterate over list of drivers on
157 * a bus to find driver by name. Return driver if found.
159 * Note that kset_find_obj increments driver's reference count.
161 struct device_driver *driver_find(const char *name, struct bus_type *bus)
163 struct kobject *k = kset_find_obj(&bus->drivers, name);
169 EXPORT_SYMBOL_GPL(driver_register);
170 EXPORT_SYMBOL_GPL(driver_unregister);
171 EXPORT_SYMBOL_GPL(get_driver);
172 EXPORT_SYMBOL_GPL(put_driver);
173 EXPORT_SYMBOL_GPL(driver_find);
175 EXPORT_SYMBOL_GPL(driver_create_file);
176 EXPORT_SYMBOL_GPL(driver_remove_file);