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// 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);
int input_get_poll_interval(struct input_dev *dev)
{
if (!dev->poller)
return -EINVAL;
return dev->poller->poll_interval;
}
EXPORT_SYMBOL(input_get_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,
};
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