/* * 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/workqueue.h>#include <linux/module.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"); 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(system_freezable_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); 	if (dev->open)		dev->open(dev); 	/* Only start polling if polling is enabled */	if (dev->poll_interval > 0) {		dev->poll(dev);		input_polldev_queue_work(dev);	} 	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); 	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 int interval;	int err; 	err = kstrtouint(buf, 0, &interval);	if (err)		return err; 	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}; static const struct attribute_group *input_polldev_attribute_groups[] = {	&input_polldev_attribute_group,	NULL}; /** * 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); struct input_polled_devres {	struct input_polled_dev *polldev;}; static int devm_input_polldev_match(struct device *dev, void *res, void *data){	struct input_polled_devres *devres = res; 	return devres->polldev == data;} static void devm_input_polldev_release(struct device *dev, void *res){	struct input_polled_devres *devres = res;	struct input_polled_dev *polldev = devres->polldev; 	dev_dbg(dev, "%s: dropping reference/freeing %s\n",		__func__, dev_name(&polldev->input->dev)); 	input_put_device(polldev->input);	kfree(polldev);} static void devm_input_polldev_unregister(struct device *dev, void *res){	struct input_polled_devres *devres = res;	struct input_polled_dev *polldev = devres->polldev; 	dev_dbg(dev, "%s: unregistering device %s\n",		__func__, dev_name(&polldev->input->dev));	input_unregister_device(polldev->input); 	/*	 * Note that we are still holding extra reference to the input	 * device so it will stick around until devm_input_polldev_release()	 * is called.	 */} /** * devm_input_allocate_polled_device - allocate managed polled device * @dev: device owning the polled device being created * * Returns prepared &struct input_polled_dev or %NULL. * * Managed polled input devices do not need to be explicitly unregistered * or freed as it will be done automatically when owner device unbinds * from * its driver (or binding fails). Once such managed polled device * is allocated, it is ready to be set up and registered in the same * fashion as regular polled input devices (using * input_register_polled_device() function). * * If you want to manually unregister and free such managed polled devices, * it can be still done by calling input_unregister_polled_device() and * input_free_polled_device(), although it is rarely needed. * * NOTE: the owner device is set up as parent of input device and users * should not override it. */struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev){	struct input_polled_dev *polldev;	struct input_polled_devres *devres; 	devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),			      GFP_KERNEL);	if (!devres)		return NULL; 	polldev = input_allocate_polled_device();	if (!polldev) {		devres_free(devres);		return NULL;	} 	polldev->input->dev.parent = dev;	polldev->devres_managed = true; 	devres->polldev = polldev;	devres_add(dev, devres); 	return polldev;}EXPORT_SYMBOL(devm_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) {		if (dev->devres_managed)			WARN_ON(devres_destroy(dev->input->dev.parent,						devm_input_polldev_release,						devm_input_polldev_match,						dev));		input_put_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_polled_devres *devres = NULL;	struct input_dev *input = dev->input;	int error; 	if (dev->devres_managed) {		devres = devres_alloc(devm_input_polldev_unregister,				      sizeof(*devres), GFP_KERNEL);		if (!devres)			return -ENOMEM; 		devres->polldev = dev;	} 	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; 	input->dev.groups = input_polldev_attribute_groups; 	error = input_register_device(input);	if (error) {		devres_free(devres);		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); 	if (dev->devres_managed) {		dev_dbg(input->dev.parent, "%s: registering %s with devres.\n",			__func__, dev_name(&input->dev));		devres_add(input->dev.parent, devres);	} 	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){	if (dev->devres_managed)		WARN_ON(devres_destroy(dev->input->dev.parent,					devm_input_polldev_unregister,					devm_input_polldev_match,					dev)); 	input_unregister_device(dev->input);}EXPORT_SYMBOL(input_unregister_polled_device);