Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * driver.c - centralized device driver management
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 *
7 * This file is released under the GPLv2
8 *
9 */
10
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>
16#include "base.h"
17
18#define to_dev(node) container_of(node, struct device, driver_list)
19#define to_drv(obj) container_of(obj, struct device_driver, kobj)
20
21/**
22 * driver_create_file - create sysfs file for driver.
23 * @drv: driver.
24 * @attr: driver attribute descriptor.
25 */
26
27int driver_create_file(struct device_driver * drv, struct driver_attribute * attr)
28{
29 int error;
30 if (get_driver(drv)) {
31 error = sysfs_create_file(&drv->kobj, &attr->attr);
32 put_driver(drv);
33 } else
34 error = -EINVAL;
35 return error;
36}
37
38
39/**
40 * driver_remove_file - remove sysfs file for driver.
41 * @drv: driver.
42 * @attr: driver attribute descriptor.
43 */
44
45void driver_remove_file(struct device_driver * drv, struct driver_attribute * attr)
46{
47 if (get_driver(drv)) {
48 sysfs_remove_file(&drv->kobj, &attr->attr);
49 put_driver(drv);
50 }
51}
52
53
54/**
55 * get_driver - increment driver reference count.
56 * @drv: driver.
57 */
58struct device_driver * get_driver(struct device_driver * drv)
59{
60 return drv ? to_drv(kobject_get(&drv->kobj)) : NULL;
61}
62
63
64/**
65 * put_driver - decrement driver's refcount.
66 * @drv: driver.
67 */
68void put_driver(struct device_driver * drv)
69{
70 kobject_put(&drv->kobj);
71}
72
73
74/**
75 * driver_register - register driver with bus
76 * @drv: driver to register
77 *
78 * We pass off most of the work to the bus_add_driver() call,
79 * since most of the things we have to do deal with the bus
80 * structures.
81 *
82 * The one interesting aspect is that we setup @drv->unloaded
83 * as a completion that gets complete when the driver reference
84 * count reaches 0.
85 */
86int driver_register(struct device_driver * drv)
87{
88 INIT_LIST_HEAD(&drv->devices);
89 init_completion(&drv->unloaded);
90 return bus_add_driver(drv);
91}
92
93
94/**
95 * driver_unregister - remove driver from system.
96 * @drv: driver.
97 *
98 * Again, we pass off most of the work to the bus-level call.
99 *
100 * Though, once that is done, we wait until @drv->unloaded is completed.
101 * This will block until the driver refcount reaches 0, and it is
102 * released. Only modular drivers will call this function, and we
103 * have to guarantee that it won't complete, letting the driver
104 * unload until all references are gone.
105 */
106
107void driver_unregister(struct device_driver * drv)
108{
109 bus_remove_driver(drv);
110 wait_for_completion(&drv->unloaded);
111}
112
113/**
114 * driver_find - locate driver on a bus by its name.
115 * @name: name of the driver.
116 * @bus: bus to scan for the driver.
117 *
118 * Call kset_find_obj() to iterate over list of drivers on
119 * a bus to find driver by name. Return driver if found.
120 *
121 * Note that kset_find_obj increments driver's reference count.
122 */
123struct device_driver *driver_find(const char *name, struct bus_type *bus)
124{
125 struct kobject *k = kset_find_obj(&bus->drivers, name);
126 if (k)
127 return to_drv(k);
128 return NULL;
129}
130
131EXPORT_SYMBOL_GPL(driver_register);
132EXPORT_SYMBOL_GPL(driver_unregister);
133EXPORT_SYMBOL_GPL(get_driver);
134EXPORT_SYMBOL_GPL(put_driver);
135EXPORT_SYMBOL_GPL(driver_find);
136
137EXPORT_SYMBOL_GPL(driver_create_file);
138EXPORT_SYMBOL_GPL(driver_remove_file);