// SPDX-License-Identifier: GPL-2.0-only/* * Support for polling mode for input devices. */ #include <linux/device.h>#include <linux/input.h>#include <linux/jiffies.h>#include <linux/mutex.h>#include <linux/slab.h>#include <linux/types.h>#include <linux/workqueue.h>#include "input-poller.h" struct input_dev_poller {	void (*poll)(struct input_dev *dev); 	unsigned int poll_interval; /* msec */	unsigned int poll_interval_max; /* msec */	unsigned int poll_interval_min; /* msec */ 	struct input_dev *input;	struct delayed_work work;}; static void input_dev_poller_queue_work(struct input_dev_poller *poller){	unsigned long delay; 	delay = msecs_to_jiffies(poller->poll_interval);	if (delay >= HZ)		delay = round_jiffies_relative(delay); 	queue_delayed_work(system_freezable_wq, &poller->work, delay);} static void input_dev_poller_work(struct work_struct *work){	struct input_dev_poller *poller =		container_of(work, struct input_dev_poller, work.work); 	poller->poll(poller->input);	input_dev_poller_queue_work(poller);} void input_dev_poller_finalize(struct input_dev_poller *poller){	if (!poller->poll_interval)		poller->poll_interval = 500;	if (!poller->poll_interval_max)		poller->poll_interval_max = poller->poll_interval;} void input_dev_poller_start(struct input_dev_poller *poller){	/* Only start polling if polling is enabled */	if (poller->poll_interval > 0) {		poller->poll(poller->input);		input_dev_poller_queue_work(poller);	}} void input_dev_poller_stop(struct input_dev_poller *poller){	cancel_delayed_work_sync(&poller->work);} int input_setup_polling(struct input_dev *dev,			void (*poll_fn)(struct input_dev *dev)){	struct input_dev_poller *poller; 	poller = kzalloc(sizeof(*poller), GFP_KERNEL);	if (!poller) {		/*		 * We want to show message even though kzalloc() may have		 * printed backtrace as knowing what instance of input		 * device we were dealing with is helpful.		 */		dev_err(dev->dev.parent ?: &dev->dev,			"%s: unable to allocate poller structure\n", __func__);		return -ENOMEM;	} 	INIT_DELAYED_WORK(&poller->work, input_dev_poller_work);	poller->input = dev;	poller->poll = poll_fn; 	dev->poller = poller;	return 0;}EXPORT_SYMBOL(input_setup_polling); static bool input_dev_ensure_poller(struct input_dev *dev){	if (!dev->poller) {		dev_err(dev->dev.parent ?: &dev->dev,			"poller structure has not been set up\n");		return false;	} 	return true;} void input_set_poll_interval(struct input_dev *dev, unsigned int interval){	if (input_dev_ensure_poller(dev))		dev->poller->poll_interval = interval;}EXPORT_SYMBOL(input_set_poll_interval); void input_set_min_poll_interval(struct input_dev *dev, unsigned int interval){	if (input_dev_ensure_poller(dev))		dev->poller->poll_interval_min = interval;}EXPORT_SYMBOL(input_set_min_poll_interval); void input_set_max_poll_interval(struct input_dev *dev, unsigned int interval){	if (input_dev_ensure_poller(dev))		dev->poller->poll_interval_max = interval;}EXPORT_SYMBOL(input_set_max_poll_interval); /* SYSFS interface */ static ssize_t input_dev_get_poll_interval(struct device *dev,					   struct device_attribute *attr,					   char *buf){	struct input_dev *input = to_input_dev(dev); 	return sprintf(buf, "%d\n", input->poller->poll_interval);} static ssize_t input_dev_set_poll_interval(struct device *dev,					   struct device_attribute *attr,					   const char *buf, size_t count){	struct input_dev *input = to_input_dev(dev);	struct input_dev_poller *poller = input->poller;	unsigned int interval;	int err; 	err = kstrtouint(buf, 0, &interval);	if (err)		return err; 	if (interval < poller->poll_interval_min)		return -EINVAL; 	if (interval > poller->poll_interval_max)		return -EINVAL; 	mutex_lock(&input->mutex); 	poller->poll_interval = interval; 	if (input->users) {		cancel_delayed_work_sync(&poller->work);		if (poller->poll_interval > 0)			input_dev_poller_queue_work(poller);	} 	mutex_unlock(&input->mutex); 	return count;} static DEVICE_ATTR(poll, 0644,		   input_dev_get_poll_interval, input_dev_set_poll_interval); static ssize_t input_dev_get_poll_max(struct device *dev,				      struct device_attribute *attr, char *buf){	struct input_dev *input = to_input_dev(dev); 	return sprintf(buf, "%d\n", input->poller->poll_interval_max);} static DEVICE_ATTR(max, 0444, input_dev_get_poll_max, NULL); static ssize_t input_dev_get_poll_min(struct device *dev,				     struct device_attribute *attr, char *buf){	struct input_dev *input = to_input_dev(dev); 	return sprintf(buf, "%d\n", input->poller->poll_interval_min);} static DEVICE_ATTR(min, 0444, input_dev_get_poll_min, NULL); static umode_t input_poller_attrs_visible(struct kobject *kobj,					  struct attribute *attr, int n){	struct device *dev = kobj_to_dev(kobj);	struct input_dev *input = to_input_dev(dev); 	return input->poller ? attr->mode : 0;} static struct attribute *input_poller_attrs[] = {	&dev_attr_poll.attr,	&dev_attr_max.attr,	&dev_attr_min.attr,	NULL}; struct attribute_group input_poller_attribute_group = {	.is_visible	= input_poller_attrs_visible,	.attrs		= input_poller_attrs,};