/*
* 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);
