Driver core: keep PHYSDEV for old struct class_device
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / base / dd.c
blob92428e55b0c210a8c00cf8e656a934fa9e21f2d3
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
15 * This file is released under the GPLv2
18 #include <linux/device.h>
19 #include <linux/module.h>
20 #include <linux/kthread.h>
21 #include <linux/wait.h>
23 #include "base.h"
24 #include "power/power.h"
26 #define to_drv(node) container_of(node, struct device_driver, kobj.entry)
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 __FUNCTION__, kobject_name(&dev->kobj));
34 return;
37 pr_debug("bound device '%s' to driver '%s'\n",
38 dev->bus_id, dev->driver->name);
40 if (dev->bus)
41 blocking_notifier_call_chain(&dev->bus->bus_notifier,
42 BUS_NOTIFY_BOUND_DRIVER, dev);
44 klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices);
47 static int driver_sysfs_add(struct device *dev)
49 int ret;
51 ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj,
52 kobject_name(&dev->kobj));
53 if (ret == 0) {
54 ret = sysfs_create_link(&dev->kobj, &dev->driver->kobj,
55 "driver");
56 if (ret)
57 sysfs_remove_link(&dev->driver->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->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;
97 static atomic_t probe_count = ATOMIC_INIT(0);
98 static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
100 static int really_probe(struct device *dev, struct device_driver *drv)
102 int ret = 0;
104 atomic_inc(&probe_count);
105 pr_debug("%s: Probing driver %s with device %s\n",
106 drv->bus->name, drv->name, dev->bus_id);
107 WARN_ON(!list_empty(&dev->devres_head));
109 dev->driver = drv;
110 if (driver_sysfs_add(dev)) {
111 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
112 __FUNCTION__, dev->bus_id);
113 goto probe_failed;
116 if (dev->bus->probe) {
117 ret = dev->bus->probe(dev);
118 if (ret)
119 goto probe_failed;
120 } else if (drv->probe) {
121 ret = drv->probe(dev);
122 if (ret)
123 goto probe_failed;
126 driver_bound(dev);
127 ret = 1;
128 pr_debug("%s: Bound Device %s to Driver %s\n",
129 drv->bus->name, dev->bus_id, drv->name);
130 goto done;
132 probe_failed:
133 devres_release_all(dev);
134 driver_sysfs_remove(dev);
135 dev->driver = NULL;
137 if (ret != -ENODEV && ret != -ENXIO) {
138 /* driver matched but the probe failed */
139 printk(KERN_WARNING
140 "%s: probe of %s failed with error %d\n",
141 drv->name, dev->bus_id, ret);
144 * Ignore errors returned by ->probe so that the next driver can try
145 * its luck.
147 ret = 0;
148 done:
149 atomic_dec(&probe_count);
150 wake_up(&probe_waitqueue);
151 return ret;
155 * driver_probe_done
156 * Determine if the probe sequence is finished or not.
158 * Should somehow figure out how to use a semaphore, not an atomic variable...
160 int driver_probe_done(void)
162 pr_debug("%s: probe_count = %d\n", __FUNCTION__,
163 atomic_read(&probe_count));
164 if (atomic_read(&probe_count))
165 return -EBUSY;
166 return 0;
170 * driver_probe_device - attempt to bind device & driver together
171 * @drv: driver to bind a device to
172 * @dev: device to try to bind to the driver
174 * First, we call the bus's match function, if one present, which should
175 * compare the device IDs the driver supports with the device IDs of the
176 * device. Note we don't do this ourselves because we don't know the
177 * format of the ID structures, nor what is to be considered a match and
178 * what is not.
180 * This function returns 1 if a match is found, -ENODEV if the device is
181 * not registered, and 0 otherwise.
183 * This function must be called with @dev->sem held. When called for a
184 * USB interface, @dev->parent->sem must be held as well.
186 int driver_probe_device(struct device_driver * drv, struct device * dev)
188 int ret = 0;
190 if (!device_is_registered(dev))
191 return -ENODEV;
192 if (drv->bus->match && !drv->bus->match(dev, drv))
193 goto done;
195 pr_debug("%s: Matched Device %s with Driver %s\n",
196 drv->bus->name, dev->bus_id, drv->name);
198 ret = really_probe(dev, drv);
200 done:
201 return ret;
204 static int __device_attach(struct device_driver * drv, void * data)
206 struct device * dev = data;
207 return driver_probe_device(drv, dev);
210 static int device_probe_drivers(void *data)
212 struct device *dev = data;
213 int ret = 0;
215 if (dev->bus) {
216 down(&dev->sem);
217 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
218 up(&dev->sem);
220 return ret;
224 * device_attach - try to attach device to a driver.
225 * @dev: device.
227 * Walk the list of drivers that the bus has and call
228 * driver_probe_device() for each pair. If a compatible
229 * pair is found, break out and return.
231 * Returns 1 if the device was bound to a driver;
232 * 0 if no matching device was found;
233 * -ENODEV if the device is not registered.
235 * When called for a USB interface, @dev->parent->sem must be held.
237 int device_attach(struct device * dev)
239 int ret = 0;
241 down(&dev->sem);
242 if (dev->driver) {
243 ret = device_bind_driver(dev);
244 if (ret == 0)
245 ret = 1;
246 else {
247 dev->driver = NULL;
248 ret = 0;
250 } else {
251 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
253 up(&dev->sem);
254 return ret;
257 static int __driver_attach(struct device * dev, void * data)
259 struct device_driver * drv = data;
262 * Lock device and try to bind to it. We drop the error
263 * here and always return 0, because we need to keep trying
264 * to bind to devices and some drivers will return an error
265 * simply if it didn't support the device.
267 * driver_probe_device() will spit a warning if there
268 * is an error.
271 if (dev->parent) /* Needed for USB */
272 down(&dev->parent->sem);
273 down(&dev->sem);
274 if (!dev->driver)
275 driver_probe_device(drv, dev);
276 up(&dev->sem);
277 if (dev->parent)
278 up(&dev->parent->sem);
280 return 0;
284 * driver_attach - try to bind driver to devices.
285 * @drv: driver.
287 * Walk the list of devices that the bus has on it and try to
288 * match the driver with each one. If driver_probe_device()
289 * returns 0 and the @dev->driver is set, we've found a
290 * compatible pair.
292 int driver_attach(struct device_driver * drv)
294 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
298 * device_release_driver - manually detach device from driver.
299 * @dev: device.
301 * Manually detach device from driver.
303 * __device_release_driver() must be called with @dev->sem held.
304 * When called for a USB interface, @dev->parent->sem must be held
305 * as well.
308 static void __device_release_driver(struct device * dev)
310 struct device_driver * drv;
312 drv = dev->driver;
313 if (drv) {
314 get_driver(drv);
315 driver_sysfs_remove(dev);
316 sysfs_remove_link(&dev->kobj, "driver");
317 klist_remove(&dev->knode_driver);
319 if (dev->bus)
320 blocking_notifier_call_chain(&dev->bus->bus_notifier,
321 BUS_NOTIFY_UNBIND_DRIVER,
322 dev);
324 if (dev->bus && dev->bus->remove)
325 dev->bus->remove(dev);
326 else if (drv->remove)
327 drv->remove(dev);
328 devres_release_all(dev);
329 dev->driver = NULL;
330 put_driver(drv);
334 void device_release_driver(struct device * dev)
337 * If anyone calls device_release_driver() recursively from
338 * within their ->remove callback for the same device, they
339 * will deadlock right here.
341 down(&dev->sem);
342 __device_release_driver(dev);
343 up(&dev->sem);
348 * driver_detach - detach driver from all devices it controls.
349 * @drv: driver.
351 void driver_detach(struct device_driver * drv)
353 struct device * dev;
355 for (;;) {
356 spin_lock(&drv->klist_devices.k_lock);
357 if (list_empty(&drv->klist_devices.k_list)) {
358 spin_unlock(&drv->klist_devices.k_lock);
359 break;
361 dev = list_entry(drv->klist_devices.k_list.prev,
362 struct device, knode_driver.n_node);
363 get_device(dev);
364 spin_unlock(&drv->klist_devices.k_lock);
366 if (dev->parent) /* Needed for USB */
367 down(&dev->parent->sem);
368 down(&dev->sem);
369 if (dev->driver == drv)
370 __device_release_driver(dev);
371 up(&dev->sem);
372 if (dev->parent)
373 up(&dev->parent->sem);
374 put_device(dev);
378 EXPORT_SYMBOL_GPL(device_bind_driver);
379 EXPORT_SYMBOL_GPL(device_release_driver);
380 EXPORT_SYMBOL_GPL(device_attach);
381 EXPORT_SYMBOL_GPL(driver_attach);