[PATCH] Add a klist to struct device_driver for the devices bound to it.
[linux-3.10.git] / drivers / base / dd.c
1 /*
2  *      drivers/base/dd.c - The core device/driver interactions.
3  *
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.
7  *
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'.
11  *
12  *      Copyright (c) 2002-5 Patrick Mochel
13  *      Copyright (c) 2002-3 Open Source Development Labs
14  *
15  *      This file is released under the GPLv2
16  */
17
18 #include <linux/device.h>
19 #include <linux/module.h>
20
21 #include "base.h"
22 #include "power/power.h"
23
24 #define to_drv(node) container_of(node, struct device_driver, kobj.entry)
25
26
27 /**
28  *      device_bind_driver - bind a driver to one device.
29  *      @dev:   device.
30  *
31  *      Allow manual attachment of a driver to a device.
32  *      Caller must have already set @dev->driver.
33  *
34  *      Note that this does not modify the bus reference count
35  *      nor take the bus's rwsem. Please verify those are accounted
36  *      for before calling this. (It is ok to call with no other effort
37  *      from a driver's probe() method.)
38  */
39 void device_bind_driver(struct device * dev)
40 {
41         pr_debug("bound device '%s' to driver '%s'\n",
42                  dev->bus_id, dev->driver->name);
43         klist_add_tail(&dev->driver->klist_devices, &dev->knode_driver);
44         sysfs_create_link(&dev->driver->kobj, &dev->kobj,
45                           kobject_name(&dev->kobj));
46         sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
47 }
48
49 /**
50  *      driver_probe_device - attempt to bind device & driver.
51  *      @drv:   driver.
52  *      @dev:   device.
53  *
54  *      First, we call the bus's match function, if one present, which
55  *      should compare the device IDs the driver supports with the
56  *      device IDs of the device. Note we don't do this ourselves
57  *      because we don't know the format of the ID structures, nor what
58  *      is to be considered a match and what is not.
59  *
60  *      If we find a match, we call @drv->probe(@dev) if it exists, and
61  *      call device_bind_driver() above.
62  */
63 int driver_probe_device(struct device_driver * drv, struct device * dev)
64 {
65         int error = 0;
66
67         if (drv->bus->match && !drv->bus->match(dev, drv))
68                 return -ENODEV;
69
70         down(&dev->sem);
71         dev->driver = drv;
72         if (drv->probe) {
73                 error = drv->probe(dev);
74                 if (error) {
75                         dev->driver = NULL;
76                         up(&dev->sem);
77                         return error;
78                 }
79         }
80         up(&dev->sem);
81         device_bind_driver(dev);
82         return 0;
83 }
84
85 /**
86  *      device_attach - try to attach device to a driver.
87  *      @dev:   device.
88  *
89  *      Walk the list of drivers that the bus has and call
90  *      driver_probe_device() for each pair. If a compatible
91  *      pair is found, break out and return.
92  */
93 int device_attach(struct device * dev)
94 {
95         struct bus_type * bus = dev->bus;
96         struct list_head * entry;
97         int error;
98
99         if (dev->driver) {
100                 device_bind_driver(dev);
101                 return 1;
102         }
103
104         if (bus->match) {
105                 list_for_each(entry, &bus->drivers.list) {
106                         struct device_driver * drv = to_drv(entry);
107                         error = driver_probe_device(drv, dev);
108                         if (!error)
109                                 /* success, driver matched */
110                                 return 1;
111                         if (error != -ENODEV && error != -ENXIO)
112                                 /* driver matched but the probe failed */
113                                 printk(KERN_WARNING
114                                     "%s: probe of %s failed with error %d\n",
115                                     drv->name, dev->bus_id, error);
116                 }
117         }
118
119         return 0;
120 }
121
122 /**
123  *      driver_attach - try to bind driver to devices.
124  *      @drv:   driver.
125  *
126  *      Walk the list of devices that the bus has on it and try to
127  *      match the driver with each one.  If driver_probe_device()
128  *      returns 0 and the @dev->driver is set, we've found a
129  *      compatible pair.
130  *
131  *      Note that we ignore the -ENODEV error from driver_probe_device(),
132  *      since it's perfectly valid for a driver not to bind to any devices.
133  */
134 void driver_attach(struct device_driver * drv)
135 {
136         struct bus_type * bus = drv->bus;
137         struct list_head * entry;
138         int error;
139
140         if (!bus->match)
141                 return;
142
143         list_for_each(entry, &bus->devices.list) {
144                 struct device * dev = container_of(entry, struct device, bus_list);
145                 if (!dev->driver) {
146                         error = driver_probe_device(drv, dev);
147                         if (error && (error != -ENODEV))
148                                 /* driver matched but the probe failed */
149                                 printk(KERN_WARNING
150                                     "%s: probe of %s failed with error %d\n",
151                                     drv->name, dev->bus_id, error);
152                 }
153         }
154 }
155
156 /**
157  *      device_release_driver - manually detach device from driver.
158  *      @dev:   device.
159  *
160  *      Manually detach device from driver.
161  *      Note that this is called without incrementing the bus
162  *      reference count nor taking the bus's rwsem. Be sure that
163  *      those are accounted for before calling this function.
164  */
165 void device_release_driver(struct device * dev)
166 {
167         struct device_driver * drv = dev->driver;
168
169         if (!drv)
170                 return;
171
172         sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
173         sysfs_remove_link(&dev->kobj, "driver");
174         klist_remove(&dev->knode_driver);
175
176         down(&dev->sem);
177         if (drv->remove)
178                 drv->remove(dev);
179         dev->driver = NULL;
180         up(&dev->sem);
181 }
182
183 static int __remove_driver(struct device * dev, void * unused)
184 {
185         device_release_driver(dev);
186         return 0;
187 }
188
189 /**
190  * driver_detach - detach driver from all devices it controls.
191  * @drv: driver.
192  */
193 void driver_detach(struct device_driver * drv)
194 {
195         driver_for_each_device(drv, NULL, NULL, __remove_driver);
196 }
197
198
199 EXPORT_SYMBOL_GPL(driver_probe_device);
200 EXPORT_SYMBOL_GPL(device_bind_driver);
201 EXPORT_SYMBOL_GPL(device_release_driver);
202 EXPORT_SYMBOL_GPL(device_attach);
203 EXPORT_SYMBOL_GPL(driver_attach);
204