[PATCH] Fix up bogus comment.
[deliverable/linux.git] / drivers / base / driver.c
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1da177e4
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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
fae3cd00 21
94e7b1c5 22static struct device * next_device(struct klist_iter * i)
23{
24 struct klist_node * n = klist_next(i);
25 return n ? container_of(n, struct device, knode_driver) : NULL;
26}
27
fae3cd00 28/**
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.
33 *
4d12d2d9 34 * Iterate over the @drv's list of devices calling @fn for each one.
fae3cd00 35 */
36
37int driver_for_each_device(struct device_driver * drv, struct device * start,
38 void * data, int (*fn)(struct device *, void *))
39{
94e7b1c5 40 struct klist_iter i;
fae3cd00 41 struct device * dev;
42 int error = 0;
43
94e7b1c5 44 if (!drv)
45 return -EINVAL;
46
47 klist_iter_init_node(&drv->klist_devices, &i,
48 start ? &start->knode_driver : NULL);
49 while ((dev = next_device(&i)) && !error)
fae3cd00 50 error = fn(dev, data);
94e7b1c5 51 klist_iter_exit(&i);
fae3cd00 52 return error;
53}
54
55EXPORT_SYMBOL(driver_for_each_device);
56
57
1da177e4
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58/**
59 * driver_create_file - create sysfs file for driver.
60 * @drv: driver.
61 * @attr: driver attribute descriptor.
62 */
63
64int driver_create_file(struct device_driver * drv, struct driver_attribute * attr)
65{
66 int error;
67 if (get_driver(drv)) {
68 error = sysfs_create_file(&drv->kobj, &attr->attr);
69 put_driver(drv);
70 } else
71 error = -EINVAL;
72 return error;
73}
74
75
76/**
77 * driver_remove_file - remove sysfs file for driver.
78 * @drv: driver.
79 * @attr: driver attribute descriptor.
80 */
81
82void driver_remove_file(struct device_driver * drv, struct driver_attribute * attr)
83{
84 if (get_driver(drv)) {
85 sysfs_remove_file(&drv->kobj, &attr->attr);
86 put_driver(drv);
87 }
88}
89
90
91/**
92 * get_driver - increment driver reference count.
93 * @drv: driver.
94 */
95struct device_driver * get_driver(struct device_driver * drv)
96{
97 return drv ? to_drv(kobject_get(&drv->kobj)) : NULL;
98}
99
100
101/**
102 * put_driver - decrement driver's refcount.
103 * @drv: driver.
104 */
105void put_driver(struct device_driver * drv)
106{
107 kobject_put(&drv->kobj);
108}
109
110
111/**
112 * driver_register - register driver with bus
113 * @drv: driver to register
114 *
115 * We pass off most of the work to the bus_add_driver() call,
116 * since most of the things we have to do deal with the bus
117 * structures.
118 *
119 * The one interesting aspect is that we setup @drv->unloaded
120 * as a completion that gets complete when the driver reference
121 * count reaches 0.
122 */
123int driver_register(struct device_driver * drv)
124{
94e7b1c5 125 klist_init(&drv->klist_devices);
1da177e4
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126 init_completion(&drv->unloaded);
127 return bus_add_driver(drv);
128}
129
130
131/**
132 * driver_unregister - remove driver from system.
133 * @drv: driver.
134 *
135 * Again, we pass off most of the work to the bus-level call.
136 *
137 * Though, once that is done, we wait until @drv->unloaded is completed.
138 * This will block until the driver refcount reaches 0, and it is
139 * released. Only modular drivers will call this function, and we
140 * have to guarantee that it won't complete, letting the driver
141 * unload until all references are gone.
142 */
143
144void driver_unregister(struct device_driver * drv)
145{
146 bus_remove_driver(drv);
147 wait_for_completion(&drv->unloaded);
148}
149
150/**
151 * driver_find - locate driver on a bus by its name.
152 * @name: name of the driver.
153 * @bus: bus to scan for the driver.
154 *
155 * Call kset_find_obj() to iterate over list of drivers on
156 * a bus to find driver by name. Return driver if found.
157 *
158 * Note that kset_find_obj increments driver's reference count.
159 */
160struct device_driver *driver_find(const char *name, struct bus_type *bus)
161{
162 struct kobject *k = kset_find_obj(&bus->drivers, name);
163 if (k)
164 return to_drv(k);
165 return NULL;
166}
167
168EXPORT_SYMBOL_GPL(driver_register);
169EXPORT_SYMBOL_GPL(driver_unregister);
170EXPORT_SYMBOL_GPL(get_driver);
171EXPORT_SYMBOL_GPL(put_driver);
172EXPORT_SYMBOL_GPL(driver_find);
173
174EXPORT_SYMBOL_GPL(driver_create_file);
175EXPORT_SYMBOL_GPL(driver_remove_file);
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