V4L/DVB (8495): usb/anysee.c: make struct anysee_usb_mutex static
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / base / dd.c
blob3ac443b2ac08579b978b7f49de2a2b73034a88cf
1 /*
2 * drivers/base/dd.c - The core device/driver interactions.
4 * This file contains the (sometimes tricky) code that controls the
5 * interactions between devices and drivers, which primarily includes
6 * driver binding and unbinding.
8 * All of this code used to exist in drivers/base/bus.c, but was
9 * relocated to here in the name of compartmentalization (since it wasn't
10 * strictly code just for the 'struct bus_type'.
12 * Copyright (c) 2002-5 Patrick Mochel
13 * Copyright (c) 2002-3 Open Source Development Labs
14 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
15 * Copyright (c) 2007 Novell Inc.
17 * This file is released under the GPLv2
20 #include <linux/device.h>
21 #include <linux/module.h>
22 #include <linux/kthread.h>
23 #include <linux/wait.h>
25 #include "base.h"
26 #include "power/power.h"
29 static void driver_bound(struct device *dev)
31 if (klist_node_attached(&dev->knode_driver)) {
32 printk(KERN_WARNING "%s: device %s already bound\n",
33 __func__, kobject_name(&dev->kobj));
34 return;
37 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->bus_id,
38 __func__, dev->driver->name);
40 if (dev->bus)
41 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
42 BUS_NOTIFY_BOUND_DRIVER, dev);
44 klist_add_tail(&dev->knode_driver, &dev->driver->p->klist_devices);
47 static int driver_sysfs_add(struct device *dev)
49 int ret;
51 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
52 kobject_name(&dev->kobj));
53 if (ret == 0) {
54 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
55 "driver");
56 if (ret)
57 sysfs_remove_link(&dev->driver->p->kobj,
58 kobject_name(&dev->kobj));
60 return ret;
63 static void driver_sysfs_remove(struct device *dev)
65 struct device_driver *drv = dev->driver;
67 if (drv) {
68 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
69 sysfs_remove_link(&dev->kobj, "driver");
73 /**
74 * device_bind_driver - bind a driver to one device.
75 * @dev: device.
77 * Allow manual attachment of a driver to a device.
78 * Caller must have already set @dev->driver.
80 * Note that this does not modify the bus reference count
81 * nor take the bus's rwsem. Please verify those are accounted
82 * for before calling this. (It is ok to call with no other effort
83 * from a driver's probe() method.)
85 * This function must be called with @dev->sem held.
87 int device_bind_driver(struct device *dev)
89 int ret;
91 ret = driver_sysfs_add(dev);
92 if (!ret)
93 driver_bound(dev);
94 return ret;
96 EXPORT_SYMBOL_GPL(device_bind_driver);
98 static atomic_t probe_count = ATOMIC_INIT(0);
99 static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
101 static int really_probe(struct device *dev, struct device_driver *drv)
103 int ret = 0;
105 atomic_inc(&probe_count);
106 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
107 drv->bus->name, __func__, drv->name, dev->bus_id);
108 WARN_ON(!list_empty(&dev->devres_head));
110 dev->driver = drv;
111 if (driver_sysfs_add(dev)) {
112 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
113 __func__, dev->bus_id);
114 goto probe_failed;
117 if (dev->bus->probe) {
118 ret = dev->bus->probe(dev);
119 if (ret)
120 goto probe_failed;
121 } else if (drv->probe) {
122 ret = drv->probe(dev);
123 if (ret)
124 goto probe_failed;
127 driver_bound(dev);
128 ret = 1;
129 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
130 drv->bus->name, __func__, dev->bus_id, drv->name);
131 goto done;
133 probe_failed:
134 devres_release_all(dev);
135 driver_sysfs_remove(dev);
136 dev->driver = NULL;
138 if (ret != -ENODEV && ret != -ENXIO) {
139 /* driver matched but the probe failed */
140 printk(KERN_WARNING
141 "%s: probe of %s failed with error %d\n",
142 drv->name, dev->bus_id, ret);
145 * Ignore errors returned by ->probe so that the next driver can try
146 * its luck.
148 ret = 0;
149 done:
150 atomic_dec(&probe_count);
151 wake_up(&probe_waitqueue);
152 return ret;
156 * driver_probe_done
157 * Determine if the probe sequence is finished or not.
159 * Should somehow figure out how to use a semaphore, not an atomic variable...
161 int driver_probe_done(void)
163 pr_debug("%s: probe_count = %d\n", __func__,
164 atomic_read(&probe_count));
165 if (atomic_read(&probe_count))
166 return -EBUSY;
167 return 0;
171 * driver_probe_device - attempt to bind device & driver together
172 * @drv: driver to bind a device to
173 * @dev: device to try to bind to the driver
175 * First, we call the bus's match function, if one present, which should
176 * compare the device IDs the driver supports with the device IDs of the
177 * device. Note we don't do this ourselves because we don't know the
178 * format of the ID structures, nor what is to be considered a match and
179 * what is not.
181 * This function returns 1 if a match is found, -ENODEV if the device is
182 * not registered, and 0 otherwise.
184 * This function must be called with @dev->sem held. When called for a
185 * USB interface, @dev->parent->sem must be held as well.
187 int driver_probe_device(struct device_driver *drv, struct device *dev)
189 int ret = 0;
191 if (!device_is_registered(dev))
192 return -ENODEV;
193 if (drv->bus->match && !drv->bus->match(dev, drv))
194 goto done;
196 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
197 drv->bus->name, __func__, dev->bus_id, drv->name);
199 ret = really_probe(dev, drv);
201 done:
202 return ret;
205 static int __device_attach(struct device_driver *drv, void *data)
207 struct device *dev = data;
208 return driver_probe_device(drv, dev);
212 * device_attach - try to attach device to a driver.
213 * @dev: device.
215 * Walk the list of drivers that the bus has and call
216 * driver_probe_device() for each pair. If a compatible
217 * pair is found, break out and return.
219 * Returns 1 if the device was bound to a driver;
220 * 0 if no matching device was found;
221 * -ENODEV if the device is not registered.
223 * When called for a USB interface, @dev->parent->sem must be held.
225 int device_attach(struct device *dev)
227 int ret = 0;
229 down(&dev->sem);
230 if (dev->driver) {
231 ret = device_bind_driver(dev);
232 if (ret == 0)
233 ret = 1;
234 else {
235 dev->driver = NULL;
236 ret = 0;
238 } else {
239 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
241 up(&dev->sem);
242 return ret;
244 EXPORT_SYMBOL_GPL(device_attach);
246 static int __driver_attach(struct device *dev, void *data)
248 struct device_driver *drv = data;
251 * Lock device and try to bind to it. We drop the error
252 * here and always return 0, because we need to keep trying
253 * to bind to devices and some drivers will return an error
254 * simply if it didn't support the device.
256 * driver_probe_device() will spit a warning if there
257 * is an error.
260 if (dev->parent) /* Needed for USB */
261 down(&dev->parent->sem);
262 down(&dev->sem);
263 if (!dev->driver)
264 driver_probe_device(drv, dev);
265 up(&dev->sem);
266 if (dev->parent)
267 up(&dev->parent->sem);
269 return 0;
273 * driver_attach - try to bind driver to devices.
274 * @drv: driver.
276 * Walk the list of devices that the bus has on it and try to
277 * match the driver with each one. If driver_probe_device()
278 * returns 0 and the @dev->driver is set, we've found a
279 * compatible pair.
281 int driver_attach(struct device_driver *drv)
283 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
285 EXPORT_SYMBOL_GPL(driver_attach);
288 * __device_release_driver() must be called with @dev->sem held.
289 * When called for a USB interface, @dev->parent->sem must be held as well.
291 static void __device_release_driver(struct device *dev)
293 struct device_driver *drv;
295 drv = dev->driver;
296 if (drv) {
297 driver_sysfs_remove(dev);
298 sysfs_remove_link(&dev->kobj, "driver");
300 if (dev->bus)
301 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
302 BUS_NOTIFY_UNBIND_DRIVER,
303 dev);
305 if (dev->bus && dev->bus->remove)
306 dev->bus->remove(dev);
307 else if (drv->remove)
308 drv->remove(dev);
309 devres_release_all(dev);
310 dev->driver = NULL;
311 klist_remove(&dev->knode_driver);
316 * device_release_driver - manually detach device from driver.
317 * @dev: device.
319 * Manually detach device from driver.
320 * When called for a USB interface, @dev->parent->sem must be held.
322 void device_release_driver(struct device *dev)
325 * If anyone calls device_release_driver() recursively from
326 * within their ->remove callback for the same device, they
327 * will deadlock right here.
329 down(&dev->sem);
330 __device_release_driver(dev);
331 up(&dev->sem);
333 EXPORT_SYMBOL_GPL(device_release_driver);
336 * driver_detach - detach driver from all devices it controls.
337 * @drv: driver.
339 void driver_detach(struct device_driver *drv)
341 struct device *dev;
343 for (;;) {
344 spin_lock(&drv->p->klist_devices.k_lock);
345 if (list_empty(&drv->p->klist_devices.k_list)) {
346 spin_unlock(&drv->p->klist_devices.k_lock);
347 break;
349 dev = list_entry(drv->p->klist_devices.k_list.prev,
350 struct device, knode_driver.n_node);
351 get_device(dev);
352 spin_unlock(&drv->p->klist_devices.k_lock);
354 if (dev->parent) /* Needed for USB */
355 down(&dev->parent->sem);
356 down(&dev->sem);
357 if (dev->driver == drv)
358 __device_release_driver(dev);
359 up(&dev->sem);
360 if (dev->parent)
361 up(&dev->parent->sem);
362 put_device(dev);