drivers/base/driver.c

   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  * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
   7  * Copyright (c) 2007 Novell Inc.
   8  *
   9  * This file is released under the GPLv2
  10  *
  11  */
  12
  13 #include <linux/device.h>
  14 #include <linux/module.h>
  15 #include <linux/errno.h>
  16 #include <linux/string.h>
  17 #include "base.h"
  18
  19 #define to_dev(node) container_of(node, struct device, driver_list)
  20
  21
  22 static 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
  28 /**
  29  *      driver_for_each_device - Iterator for devices bound to a driver.
  30  *      @drv:   Driver we're iterating.
  31  *      @start: Device to begin with
  32  *      @data:  Data to pass to the callback.
  33  *      @fn:    Function to call for each device.
  34  *
  35  *      Iterate over the @drv's list of devices calling @fn for each one.
  36  */
  37
  38 int driver_for_each_device(struct device_driver * drv, struct device * start,
  39                            void * data, int (*fn)(struct device *, void *))
  40 {
  41         struct klist_iter i;
  42         struct device * dev;
  43         int error = 0;
  44
  45         if (!drv)
  46                 return -EINVAL;
  47
  48         klist_iter_init_node(&drv->p->klist_devices, &i,
  49                              start ? &start->knode_driver : NULL);
  50         while ((dev = next_device(&i)) && !error)
  51                 error = fn(dev, data);
  52         klist_iter_exit(&i);
  53         return error;
  54 }
  55
  56 EXPORT_SYMBOL_GPL(driver_for_each_device);
  57
  58
  59 /**
  60  * driver_find_device - device iterator for locating a particular device.
  61  * @drv: The device's driver
  62  * @start: Device to begin with
  63  * @data: Data to pass to match function
  64  * @match: Callback function to check device
  65  *
  66  * This is similar to the driver_for_each_device() function above, but
  67  * it returns a reference to a device that is 'found' for later use, as
  68  * determined by the @match callback.
  69  *
  70  * The callback should return 0 if the device doesn't match and non-zero
  71  * if it does.  If the callback returns non-zero, this function will
  72  * return to the caller and not iterate over any more devices.
  73  */
  74 struct device * driver_find_device(struct device_driver *drv,
  75                                    struct device * start, void * data,
  76                                    int (*match)(struct device *, void *))
  77 {
  78         struct klist_iter i;
  79         struct device *dev;
  80
  81         if (!drv)
  82                 return NULL;
  83
  84         klist_iter_init_node(&drv->p->klist_devices, &i,
  85                              (start ? &start->knode_driver : NULL));
  86         while ((dev = next_device(&i)))
  87                 if (match(dev, data) && get_device(dev))
  88                         break;
  89         klist_iter_exit(&i);
  90         return dev;
  91 }
  92 EXPORT_SYMBOL_GPL(driver_find_device);
  93
  94 /**
  95  *      driver_create_file - create sysfs file for driver.
  96  *      @drv:   driver.
  97  *      @attr:  driver attribute descriptor.
  98  */
  99
 100 int driver_create_file(struct device_driver * drv, struct driver_attribute * attr)
 101 {
 102         int error;
 103         if (get_driver(drv)) {
 104                 error = sysfs_create_file(&drv->p->kobj, &attr->attr);
 105                 put_driver(drv);
 106         } else
 107                 error = -EINVAL;
 108         return error;
 109 }
 110
 111
 112 /**
 113  *      driver_remove_file - remove sysfs file for driver.
 114  *      @drv:   driver.
 115  *      @attr:  driver attribute descriptor.
 116  */
 117
 118 void driver_remove_file(struct device_driver * drv, struct driver_attribute * attr)
 119 {
 120         if (get_driver(drv)) {
 121                 sysfs_remove_file(&drv->p->kobj, &attr->attr);
 122                 put_driver(drv);
 123         }
 124 }
 125
 126
 127 /**
 128  * driver_add_kobj - add a kobject below the specified driver
 129  *
 130  * You really don't want to do this, this is only here due to one looney
 131  * iseries driver, go poke those developers if you are annoyed about
 132  * this...
 133  */
 134 int driver_add_kobj(struct device_driver *drv, struct kobject *kobj,
 135                     const char *fmt, ...)
 136 {
 137         va_list args;
 138         char *name;
 139
 140         va_start(args, fmt);
 141         name = kvasprintf(GFP_KERNEL, fmt, args);
 142         va_end(args);
 143
 144         if (!name)
 145                 return -ENOMEM;
 146
 147         return kobject_add_ng(kobj, &drv->p->kobj, "%s", name);
 148 }
 149 EXPORT_SYMBOL_GPL(driver_add_kobj);
 150
 151 /**
 152  *      get_driver - increment driver reference count.
 153  *      @drv:   driver.
 154  */
 155 struct device_driver * get_driver(struct device_driver * drv)
 156 {
 157         if (drv) {
 158                 struct driver_private *priv;
 159                 struct kobject *kobj;
 160
 161                 kobj = kobject_get(&drv->p->kobj);
 162                 priv = to_driver(kobj);
 163                 return priv->driver;
 164         }
 165         return NULL;
 166 }
 167
 168
 169 /**
 170  *      put_driver - decrement driver's refcount.
 171  *      @drv:   driver.
 172  */
 173 void put_driver(struct device_driver * drv)
 174 {
 175         kobject_put(&drv->p->kobj);
 176 }
 177
 178 static int driver_add_groups(struct device_driver *drv,
 179                              struct attribute_group **groups)
 180 {
 181         int error = 0;
 182         int i;
 183
 184         if (groups) {
 185                 for (i = 0; groups[i]; i++) {
 186                         error = sysfs_create_group(&drv->p->kobj, groups[i]);
 187                         if (error) {
 188                                 while (--i >= 0)
 189                                         sysfs_remove_group(&drv->p->kobj,
 190                                                            groups[i]);
 191                                 break;
 192                         }
 193                 }
 194         }
 195         return error;
 196 }
 197
 198 static void driver_remove_groups(struct device_driver *drv,
 199                                  struct attribute_group **groups)
 200 {
 201         int i;
 202
 203         if (groups)
 204                 for (i = 0; groups[i]; i++)
 205                         sysfs_remove_group(&drv->p->kobj, groups[i]);
 206 }
 207
 208
 209 /**
 210  *      driver_register - register driver with bus
 211  *      @drv:   driver to register
 212  *
 213  *      We pass off most of the work to the bus_add_driver() call,
 214  *      since most of the things we have to do deal with the bus
 215  *      structures.
 216  */
 217 int driver_register(struct device_driver * drv)
 218 {
 219         int ret;
 220
 221         if ((drv->bus->probe && drv->probe) ||
 222             (drv->bus->remove && drv->remove) ||
 223             (drv->bus->shutdown && drv->shutdown)) {
 224                 printk(KERN_WARNING "Driver '%s' needs updating - please use bus_type methods\n", drv->name);
 225         }
 226         ret = bus_add_driver(drv);
 227         if (ret)
 228                 return ret;
 229         ret = driver_add_groups(drv, drv->groups);
 230         if (ret)
 231                 bus_remove_driver(drv);
 232         return ret;
 233 }
 234
 235 /**
 236  *      driver_unregister - remove driver from system.
 237  *      @drv:   driver.
 238  *
 239  *      Again, we pass off most of the work to the bus-level call.
 240  */
 241
 242 void driver_unregister(struct device_driver * drv)
 243 {
 244         driver_remove_groups(drv, drv->groups);
 245         bus_remove_driver(drv);
 246 }
 247
 248 /**
 249  *      driver_find - locate driver on a bus by its name.
 250  *      @name:  name of the driver.
 251  *      @bus:   bus to scan for the driver.
 252  *
 253  *      Call kset_find_obj() to iterate over list of drivers on
 254  *      a bus to find driver by name. Return driver if found.
 255  *
 256  *      Note that kset_find_obj increments driver's reference count.
 257  */
 258 struct device_driver *driver_find(const char *name, struct bus_type *bus)
 259 {
 260         struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
 261         struct driver_private *priv;
 262
 263         if (k) {
 264                 priv = to_driver(k);
 265                 return priv->driver;
 266         }
 267         return NULL;
 268 }
 269
 270 EXPORT_SYMBOL_GPL(driver_register);
 271 EXPORT_SYMBOL_GPL(driver_unregister);
 272 EXPORT_SYMBOL_GPL(get_driver);
 273 EXPORT_SYMBOL_GPL(put_driver);
 274 EXPORT_SYMBOL_GPL(driver_find);
 275
 276 EXPORT_SYMBOL_GPL(driver_create_file);
 277 EXPORT_SYMBOL_GPL(driver_remove_file);