/* * Generic implementation of a polled input device  * Copyright (c) 2007 Dmitry Torokhov * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published by * the Free Software Foundation. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/jiffies.h>#include <linux/slab.h>#include <linux/mutex.h>#include <linux/input-polldev.h> MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");MODULE_DESCRIPTION("Generic implementation of a polled input device");MODULE_LICENSE("GPL v2");MODULE_VERSION("0.1"); static DEFINE_MUTEX(polldev_mutex);static int polldev_users;static struct workqueue_struct *polldev_wq; static int input_polldev_start_workqueue(void){	int retval; 	retval = mutex_lock_interruptible(&polldev_mutex);	if (retval)		return retval; 	if (!polldev_users) {		polldev_wq = create_singlethread_workqueue("ipolldevd");		if (!polldev_wq) {			pr_err("failed to create ipolldevd workqueue\n");			retval = -ENOMEM;			goto out;		}	} 	polldev_users++;  out:	mutex_unlock(&polldev_mutex);	return retval;} static void input_polldev_stop_workqueue(void){	mutex_lock(&polldev_mutex); 	if (!--polldev_users)		destroy_workqueue(polldev_wq); 	mutex_unlock(&polldev_mutex);} static void input_polldev_queue_work(struct input_polled_dev *dev){	unsigned long delay; 	delay = msecs_to_jiffies(dev->poll_interval);	if (delay >= HZ)		delay = round_jiffies_relative(delay); 	queue_delayed_work(polldev_wq, &dev->work, delay);} static void input_polled_device_work(struct work_struct *work){	struct input_polled_dev *dev =		container_of(work, struct input_polled_dev, work.work); 	dev->poll(dev);	input_polldev_queue_work(dev);} static int input_open_polled_device(struct input_dev *input){	struct input_polled_dev *dev = input_get_drvdata(input);	int error; 	error = input_polldev_start_workqueue();	if (error)		return error; 	if (dev->open)		dev->open(dev); 	/* Only start polling if polling is enabled */	if (dev->poll_interval > 0)		queue_delayed_work(polldev_wq, &dev->work, 0); 	return 0;} static void input_close_polled_device(struct input_dev *input){	struct input_polled_dev *dev = input_get_drvdata(input); 	cancel_delayed_work_sync(&dev->work);	/*	 * Clean up work struct to remove references to the workqueue.	 * It may be destroyed by the next call. This causes problems	 * at next device open-close in case of poll_interval == 0.	 */	INIT_DELAYED_WORK(&dev->work, dev->work.work.func);	input_polldev_stop_workqueue(); 	if (dev->close)		dev->close(dev);} /* SYSFS interface */ static ssize_t input_polldev_get_poll(struct device *dev,				      struct device_attribute *attr, char *buf){	struct input_polled_dev *polldev = dev_get_drvdata(dev); 	return sprintf(buf, "%d\n", polldev->poll_interval);} static ssize_t input_polldev_set_poll(struct device *dev,				struct device_attribute *attr, const char *buf,				size_t count){	struct input_polled_dev *polldev = dev_get_drvdata(dev);	struct input_dev *input = polldev->input;	unsigned long interval; 	if (strict_strtoul(buf, 0, &interval))		return -EINVAL; 	if (interval < polldev->poll_interval_min)		return -EINVAL; 	if (interval > polldev->poll_interval_max)		return -EINVAL; 	mutex_lock(&input->mutex); 	polldev->poll_interval = interval; 	if (input->users) {		cancel_delayed_work_sync(&polldev->work);		if (polldev->poll_interval > 0)			input_polldev_queue_work(polldev);	} 	mutex_unlock(&input->mutex); 	return count;} static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,					    input_polldev_set_poll);  static ssize_t input_polldev_get_max(struct device *dev,				     struct device_attribute *attr, char *buf){	struct input_polled_dev *polldev = dev_get_drvdata(dev); 	return sprintf(buf, "%d\n", polldev->poll_interval_max);} static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL); static ssize_t input_polldev_get_min(struct device *dev,				     struct device_attribute *attr, char *buf){	struct input_polled_dev *polldev = dev_get_drvdata(dev); 	return sprintf(buf, "%d\n", polldev->poll_interval_min);} static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL); static struct attribute *sysfs_attrs[] = {	&dev_attr_poll.attr,	&dev_attr_max.attr,	&dev_attr_min.attr,	NULL}; static struct attribute_group input_polldev_attribute_group = {	.attrs = sysfs_attrs}; /** * input_allocate_polled_device - allocate memory for polled device * * The function allocates memory for a polled device and also * for an input device associated with this polled device. */struct input_polled_dev *input_allocate_polled_device(void){	struct input_polled_dev *dev; 	dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);	if (!dev)		return NULL; 	dev->input = input_allocate_device();	if (!dev->input) {		kfree(dev);		return NULL;	} 	return dev;}EXPORT_SYMBOL(input_allocate_polled_device); /** * input_free_polled_device - free memory allocated for polled device * @dev: device to free * * The function frees memory allocated for polling device and drops * reference to the associated input device. */void input_free_polled_device(struct input_polled_dev *dev){	if (dev) {		input_free_device(dev->input);		kfree(dev);	}}EXPORT_SYMBOL(input_free_polled_device); /** * input_register_polled_device - register polled device * @dev: device to register * * The function registers previously initialized polled input device * with input layer. The device should be allocated with call to * input_allocate_polled_device(). Callers should also set up poll() * method and set up capabilities (id, name, phys, bits) of the * corresponding input_dev structure. */int input_register_polled_device(struct input_polled_dev *dev){	struct input_dev *input = dev->input;	int error; 	input_set_drvdata(input, dev);	INIT_DELAYED_WORK(&dev->work, input_polled_device_work);	if (!dev->poll_interval)		dev->poll_interval = 500;	if (!dev->poll_interval_max)		dev->poll_interval_max = dev->poll_interval;	input->open = input_open_polled_device;	input->close = input_close_polled_device; 	error = input_register_device(input);	if (error)		return error; 	error = sysfs_create_group(&input->dev.kobj,				   &input_polldev_attribute_group);	if (error) {		input_unregister_device(input);		return error;	} 	/*	 * Take extra reference to the underlying input device so	 * that it survives call to input_unregister_polled_device()	 * and is deleted only after input_free_polled_device()	 * has been invoked. This is needed to ease task of freeing	 * sparse keymaps.	 */	input_get_device(input); 	return 0;}EXPORT_SYMBOL(input_register_polled_device); /** * input_unregister_polled_device - unregister polled device * @dev: device to unregister * * The function unregisters previously registered polled input * device from input layer. Polling is stopped and device is * ready to be freed with call to input_free_polled_device(). */void input_unregister_polled_device(struct input_polled_dev *dev){	sysfs_remove_group(&dev->input->dev.kobj,			   &input_polldev_attribute_group); 	input_unregister_device(dev->input);}EXPORT_SYMBOL(input_unregister_polled_device);