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/*
* 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.
*/
#include <linux/jiffies.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) {
printk(KERN_ERR "input-polldev: 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_polled_device_work(struct work_struct *work)
{
struct input_polled_dev *dev =
container_of(work, struct input_polled_dev, work.work);
dev->poll(dev);
queue_delayed_work(polldev_wq, &dev->work,
msecs_to_jiffies(dev->poll_interval));
}
static int input_open_polled_device(struct input_dev *input)
{
struct input_polled_dev *dev = input->private;
int error;
unsigned long ticks;
error = input_polldev_start_workqueue();
if (error)
return error;
if (dev->flush)
dev->flush(dev);
ticks = msecs_to_jiffies(dev->poll_interval);
if (ticks >= HZ)
ticks = round_jiffies(ticks);
queue_delayed_work(polldev_wq, &dev->work, ticks);
return 0;
}
static void input_close_polled_device(struct input_dev *input)
{
struct input_polled_dev *dev = input->private;
cancel_rearming_delayed_workqueue(polldev_wq, &dev->work);
input_polldev_stop_workqueue();
}
/**
* input_allocate_polled_device - allocated memory 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 (if present).
*/
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
* corresponing input_dev structure.
*/
int input_register_polled_device(struct input_polled_dev *dev)
{
struct input_dev *input = dev->input;
INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
if (!dev->poll_interval)
dev->poll_interval = 500;
input->private = dev;
input->open = input_open_polled_device;
input->close = input_close_polled_device;
return input_register_device(input);
}
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().
* Callers should not attempt to access dev->input pointer
* after calling this function.
*/
void input_unregister_polled_device(struct input_polled_dev *dev)
{
input_unregister_device(dev->input);
dev->input = NULL;
}
EXPORT_SYMBOL(input_unregister_polled_device);
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