input.c

linux 内核源代码

/*
 * Input uevent interface - loading event handlers based on
 * device bitfields.
 */
static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
				   const char *name, unsigned long *bitmap, int max)
{
	int len;

	if (add_uevent_var(env, "%s=", name))
		return -ENOMEM;

	len = input_print_bitmap(&env->buf[env->buflen - 1],
				 sizeof(env->buf) - env->buflen,
				 bitmap, max, 0);
	if (len >= (sizeof(env->buf) - env->buflen))
		return -ENOMEM;

	env->buflen += len;
	return 0;
}

static int input_add_uevent_modalias_var(struct kobj_uevent_env *env,
					 struct input_dev *dev)
{
	int len;

	if (add_uevent_var(env, "MODALIAS="))
		return -ENOMEM;

	len = input_print_modalias(&env->buf[env->buflen - 1],
				   sizeof(env->buf) - env->buflen,
				   dev, 0);
	if (len >= (sizeof(env->buf) - env->buflen))
		return -ENOMEM;

	env->buflen += len;
	return 0;
}

#define INPUT_ADD_HOTPLUG_VAR(fmt, val...)				\
	do {								\
		int err = add_uevent_var(env, fmt, val);		\
		if (err)						\
			return err;					\
	} while (0)

#define INPUT_ADD_HOTPLUG_BM_VAR(name, bm, max)				\
	do {								\
		int err = input_add_uevent_bm_var(env, name, bm, max);	\
		if (err)						\
			return err;					\
	} while (0)

#define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev)				\
	do {								\
		int err = input_add_uevent_modalias_var(env, dev);	\
		if (err)						\
			return err;					\
	} while (0)

static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
{
	struct input_dev *dev = to_input_dev(device);

	INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
				dev->id.bustype, dev->id.vendor,
				dev->id.product, dev->id.version);
	if (dev->name)
		INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name);
	if (dev->phys)
		INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys);
	if (dev->uniq)
		INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq);

	INPUT_ADD_HOTPLUG_BM_VAR("EV=", dev->evbit, EV_MAX);
	if (test_bit(EV_KEY, dev->evbit))
		INPUT_ADD_HOTPLUG_BM_VAR("KEY=", dev->keybit, KEY_MAX);
	if (test_bit(EV_REL, dev->evbit))
		INPUT_ADD_HOTPLUG_BM_VAR("REL=", dev->relbit, REL_MAX);
	if (test_bit(EV_ABS, dev->evbit))
		INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX);
	if (test_bit(EV_MSC, dev->evbit))
		INPUT_ADD_HOTPLUG_BM_VAR("MSC=", dev->mscbit, MSC_MAX);
	if (test_bit(EV_LED, dev->evbit))
		INPUT_ADD_HOTPLUG_BM_VAR("LED=", dev->ledbit, LED_MAX);
	if (test_bit(EV_SND, dev->evbit))
		INPUT_ADD_HOTPLUG_BM_VAR("SND=", dev->sndbit, SND_MAX);
	if (test_bit(EV_FF, dev->evbit))
		INPUT_ADD_HOTPLUG_BM_VAR("FF=", dev->ffbit, FF_MAX);
	if (test_bit(EV_SW, dev->evbit))
		INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX);

	INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);

	return 0;
}

static struct device_type input_dev_type = {
	.groups		= input_dev_attr_groups,
	.release	= input_dev_release,
	.uevent		= input_dev_uevent,
};

struct class input_class = {
	.name		= "input",
};
EXPORT_SYMBOL_GPL(input_class);

/**
 * input_allocate_device - allocate memory for new input device
 *
 * Returns prepared struct input_dev or NULL.
 *
 * NOTE: Use input_free_device() to free devices that have not been
 * registered; input_unregister_device() should be used for already
 * registered devices.
 */
struct input_dev *input_allocate_device(void)
{
	struct input_dev *dev;

	dev = kzalloc(sizeof(struct input_dev), GFP_KERNEL);
	if (dev) {
		dev->dev.type = &input_dev_type;
		dev->dev.class = &input_class;
		device_initialize(&dev->dev);
		mutex_init(&dev->mutex);
		spin_lock_init(&dev->event_lock);
		INIT_LIST_HEAD(&dev->h_list);
		INIT_LIST_HEAD(&dev->node);

		__module_get(THIS_MODULE);
	}

	return dev;
}
EXPORT_SYMBOL(input_allocate_device);

/**
 * input_free_device - free memory occupied by input_dev structure
 * @dev: input device to free
 *
 * This function should only be used if input_register_device()
 * was not called yet or if it failed. Once device was registered
 * use input_unregister_device() and memory will be freed once last
 * reference to the device is dropped.
 *
 * Device should be allocated by input_allocate_device().
 *
 * NOTE: If there are references to the input device then memory
 * will not be freed until last reference is dropped.
 */
void input_free_device(struct input_dev *dev)
{
	if (dev)
		input_put_device(dev);
}
EXPORT_SYMBOL(input_free_device);

/**
 * input_set_capability - mark device as capable of a certain event
 * @dev: device that is capable of emitting or accepting event
 * @type: type of the event (EV_KEY, EV_REL, etc...)
 * @code: event code
 *
 * In addition to setting up corresponding bit in appropriate capability
 * bitmap the function also adjusts dev->evbit.
 */
void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code)
{
	switch (type) {
	case EV_KEY:
		__set_bit(code, dev->keybit);
		break;

	case EV_REL:
		__set_bit(code, dev->relbit);
		break;

	case EV_ABS:
		__set_bit(code, dev->absbit);
		break;

	case EV_MSC:
		__set_bit(code, dev->mscbit);
		break;

	case EV_SW:
		__set_bit(code, dev->swbit);
		break;

	case EV_LED:
		__set_bit(code, dev->ledbit);
		break;

	case EV_SND:
		__set_bit(code, dev->sndbit);
		break;

	case EV_FF:
		__set_bit(code, dev->ffbit);
		break;

	case EV_PWR:
		/* do nothing */
		break;

	default:
		printk(KERN_ERR
			"input_set_capability: unknown type %u (code %u)\n",
			type, code);
		dump_stack();
		return;
	}

	__set_bit(type, dev->evbit);
}
EXPORT_SYMBOL(input_set_capability);

/**
 * input_register_device - register device with input core
 * @dev: device to be registered
 *
 * This function registers device with input core. The device must be
 * allocated with input_allocate_device() and all it's capabilities
 * set up before registering.
 * If function fails the device must be freed with input_free_device().
 * Once device has been successfully registered it can be unregistered
 * with input_unregister_device(); input_free_device() should not be
 * called in this case.
 */
int input_register_device(struct input_dev *dev)
{
	static atomic_t input_no = ATOMIC_INIT(0);
	struct input_handler *handler;
	const char *path;
	int error;

	__set_bit(EV_SYN, dev->evbit);

	/*
	 * If delay and period are pre-set by the driver, then autorepeating
	 * is handled by the driver itself and we don't do it in input.c.
	 */

	init_timer(&dev->timer);
	if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
		dev->timer.data = (long) dev;
		dev->timer.function = input_repeat_key;
		dev->rep[REP_DELAY] = 250;
		dev->rep[REP_PERIOD] = 33;
	}

	if (!dev->getkeycode)
		dev->getkeycode = input_default_getkeycode;

	if (!dev->setkeycode)
		dev->setkeycode = input_default_setkeycode;

	snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
		 "input%ld", (unsigned long) atomic_inc_return(&input_no) - 1);

	if (dev->cdev.dev)
		dev->dev.parent = dev->cdev.dev;

	error = device_add(&dev->dev);
	if (error)
		return error;

	path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
	printk(KERN_INFO "input: %s as %s\n",
		dev->name ? dev->name : "Unspecified device", path ? path : "N/A");
	kfree(path);

	error = mutex_lock_interruptible(&input_mutex);
	if (error) {
		device_del(&dev->dev);
		return error;
	}

	list_add_tail(&dev->node, &input_dev_list);

	list_for_each_entry(handler, &input_handler_list, node)
		input_attach_handler(dev, handler);

	input_wakeup_procfs_readers();

	mutex_unlock(&input_mutex);

	return 0;
}
EXPORT_SYMBOL(input_register_device);

/**
 * input_unregister_device - unregister previously registered device
 * @dev: device to be unregistered
 *
 * This function unregisters an input device. Once device is unregistered
 * the caller should not try to access it as it may get freed at any moment.
 */
void input_unregister_device(struct input_dev *dev)
{
	struct input_handle *handle, *next;

	input_disconnect_device(dev);

	mutex_lock(&input_mutex);

	list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
		handle->handler->disconnect(handle);
	WARN_ON(!list_empty(&dev->h_list));

	del_timer_sync(&dev->timer);
	list_del_init(&dev->node);

	input_wakeup_procfs_readers();

	mutex_unlock(&input_mutex);

	device_unregister(&dev->dev);
}
EXPORT_SYMBOL(input_unregister_device);

/**
 * input_register_handler - register a new input handler
 * @handler: handler to be registered
 *
 * This function registers a new input handler (interface) for input
 * devices in the system and attaches it to all input devices that
 * are compatible with the handler.
 */
int input_register_handler(struct input_handler *handler)
{
	struct input_dev *dev;
	int retval;

	retval = mutex_lock_interruptible(&input_mutex);
	if (retval)
		return retval;

	INIT_LIST_HEAD(&handler->h_list);

	if (handler->fops != NULL) {
		if (input_table[handler->minor >> 5]) {
			retval = -EBUSY;
			goto out;
		}
		input_table[handler->minor >> 5] = handler;
	}

	list_add_tail(&handler->node, &input_handler_list);

	list_for_each_entry(dev, &input_dev_list, node)
		input_attach_handler(dev, handler);

	input_wakeup_procfs_readers();

 out:
	mutex_unlock(&input_mutex);
	return retval;
}
EXPORT_SYMBOL(input_register_handler);

/**
 * input_unregister_handler - unregisters an input handler
 * @handler: handler to be unregistered
 *
 * This function disconnects a handler from its input devices and
 * removes it from lists of known handlers.
 */
void input_unregister_handler(struct input_handler *handler)
{
	struct input_handle *handle, *next;

	mutex_lock(&input_mutex);

	list_for_each_entry_safe(handle, next, &handler->h_list, h_node)
		handler->disconnect(handle);
	WARN_ON(!list_empty(&handler->h_list));

	list_del_init(&handler->node);

	if (handler->fops != NULL)
		input_table[handler->minor >> 5] = NULL;

	input_wakeup_procfs_readers();

	mutex_unlock(&input_mutex);
}
EXPORT_SYMBOL(input_unregister_handler);

/**
 * input_register_handle - register a new input handle
 * @handle: handle to register
 *
 * This function puts a new input handle onto device's
 * and handler's lists so that events can flow through
 * it once it is opened using input_open_device().
 *
 * This function is supposed to be called from handler's
 * connect() method.
 */
int input_register_handle(struct input_handle *handle)
{
	struct input_handler *handler = handle->handler;
	struct input_dev *dev = handle->dev;
	int error;

	/*
	 * We take dev->mutex here to prevent race with
	 * input_release_device().
	 */
	error = mutex_lock_interruptible(&dev->mutex);
	if (error)
		return error;
	list_add_tail_rcu(&handle->d_node, &dev->h_list);
	mutex_unlock(&dev->mutex);
	synchronize_rcu();

	/*
	 * Since we are supposed to be called from ->connect()
	 * which is mutually exclusive with ->disconnect()
	 * we can't be racing with input_unregister_handle()
	 * and so separate lock is not needed here.
	 */
	list_add_tail(&handle->h_node, &handler->h_list);

	if (handler->start)
		handler->start(handle);

	return 0;
}
EXPORT_SYMBOL(input_register_handle);

/**
 * input_unregister_handle - unregister an input handle
 * @handle: handle to unregister
 *
 * This function removes input handle from device's
 * and handler's lists.
 *
 * This function is supposed to be called from handler's
 * disconnect() method.
 */
void input_unregister_handle(struct input_handle *handle)
{
	struct input_dev *dev = handle->dev;

	list_del_init(&handle->h_node);

	/*
	 * Take dev->mutex to prevent race with input_release_device().
	 */
	mutex_lock(&dev->mutex);
	list_del_rcu(&handle->d_node);
	mutex_unlock(&dev->mutex);
	synchronize_rcu();
}
EXPORT_SYMBOL(input_unregister_handle);

static int input_open_file(struct inode *inode, struct file *file)
{
	struct input_handler *handler = input_table[iminor(inode) >> 5];
	const struct file_operations *old_fops, *new_fops = NULL;
	int err;

	/* No load-on-demand here? */
	if (!handler || !(new_fops = fops_get(handler->fops)))
		return -ENODEV;

	/*
	 * That's _really_ odd. Usually NULL ->open means "nothing special",
	 * not "no device". Oh, well...
	 */
	if (!new_fops->open) {
		fops_put(new_fops);
		return -ENODEV;
	}
	old_fops = file->f_op;
	file->f_op = new_fops;

	err = new_fops->open(inode, file);

	if (err) {
		fops_put(file->f_op);
		file->f_op = fops_get(old_fops);
	}
	fops_put(old_fops);
	return err;
}

static const struct file_operations input_fops = {
	.owner = THIS_MODULE,
	.open = input_open_file,
};

static int __init input_init(void)
{
	int err;

	err = class_register(&input_class);
	if (err) {
		printk(KERN_ERR "input: unable to register input_dev class\n");
		return err;
	}

	err = input_proc_init();
	if (err)
		goto fail1;

	err = register_chrdev(INPUT_MAJOR, "input", &input_fops);
	if (err) {
		printk(KERN_ERR "input: unable to register char major %d", INPUT_MAJOR);
		goto fail2;
	}

	return 0;

 fail2:	input_proc_exit();
 fail1:	class_unregister(&input_class);
	return err;
}

static void __exit input_exit(void)
{
	input_proc_exit();
	unregister_chrdev(INPUT_MAJOR, "input");
	class_unregister(&input_class);
}

subsys_initcall(input_init);
module_exit(input_exit);