+
+
+static void device_create_release(struct device *dev)
+{
+ pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
+ kfree(dev);
+}
+
+/**
+ * device_create - creates a device and registers it with sysfs
+ * @cs: pointer to the struct class that this device should be registered to.
+ * @parent: pointer to the parent struct device of this new device, if any.
+ * @dev: the dev_t for the char device to be added.
+ * @fmt: string for the class device's name
+ *
+ * This function can be used by char device classes. A struct
+ * device will be created in sysfs, registered to the specified
+ * class.
+ * A "dev" file will be created, showing the dev_t for the device, if
+ * the dev_t is not 0,0.
+ * If a pointer to a parent struct device is passed in, the newly
+ * created struct device will be a child of that device in sysfs. The
+ * pointer to the struct device will be returned from the call. Any
+ * further sysfs files that might be required can be created using this
+ * pointer.
+ *
+ * Note: the struct class passed to this function must have previously
+ * been created with a call to class_create().
+ */
+struct device *device_create(struct class *class, struct device *parent,
+ dev_t devt, char *fmt, ...)
+{
+ va_list args;
+ struct device *dev = NULL;
+ int retval = -ENODEV;
+
+ if (class == NULL || IS_ERR(class))
+ goto error;
+ if (parent == NULL) {
+ printk(KERN_WARNING "%s does not work yet for NULL parents\n", __FUNCTION__);
+ goto error;
+ }
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev) {
+ retval = -ENOMEM;
+ goto error;
+ }
+
+ dev->devt = devt;
+ dev->class = class;
+ dev->parent = parent;
+ dev->release = device_create_release;
+
+ va_start(args, fmt);
+ vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
+ va_end(args);
+ retval = device_register(dev);
+ if (retval)
+ goto error;
+
+ return dev;
+
+error:
+ kfree(dev);
+ return ERR_PTR(retval);
+}
+EXPORT_SYMBOL_GPL(device_create);
+
+/**
+ * device_destroy - removes a device that was created with device_create()
+ * @class: the pointer to the struct class that this device was registered * with.
+ * @dev: the dev_t of the device that was previously registered.
+ *
+ * This call unregisters and cleans up a class device that was created with a
+ * call to class_device_create()
+ */
+void device_destroy(struct class *class, dev_t devt)
+{
+ struct device *dev = NULL;
+ struct device *dev_tmp;
+
+ down(&class->sem);
+ list_for_each_entry(dev_tmp, &class->devices, node) {
+ if (dev_tmp->devt == devt) {
+ dev = dev_tmp;
+ break;
+ }
+ }
+ up(&class->sem);
+
+ if (dev)
+ device_unregister(dev);
+}
+EXPORT_SYMBOL_GPL(device_destroy);