180 lines
4.4 KiB
C
180 lines
4.4 KiB
C
/*
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* Generic implementation of a polled input device
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* Copyright (c) 2007 Dmitry Torokhov
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/jiffies.h>
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#include <linux/mutex.h>
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#include <linux/input-polldev.h>
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MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
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MODULE_DESCRIPTION("Generic implementation of a polled input device");
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MODULE_LICENSE("GPL v2");
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MODULE_VERSION("0.1");
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static DEFINE_MUTEX(polldev_mutex);
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static int polldev_users;
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static struct workqueue_struct *polldev_wq;
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static int input_polldev_start_workqueue(void)
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{
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int retval;
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retval = mutex_lock_interruptible(&polldev_mutex);
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if (retval)
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return retval;
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if (!polldev_users) {
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polldev_wq = create_singlethread_workqueue("ipolldevd");
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if (!polldev_wq) {
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printk(KERN_ERR "input-polldev: failed to create "
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"ipolldevd workqueue\n");
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retval = -ENOMEM;
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goto out;
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}
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}
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polldev_users++;
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out:
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mutex_unlock(&polldev_mutex);
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return retval;
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}
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static void input_polldev_stop_workqueue(void)
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{
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mutex_lock(&polldev_mutex);
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if (!--polldev_users)
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destroy_workqueue(polldev_wq);
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mutex_unlock(&polldev_mutex);
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}
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static void input_polled_device_work(struct work_struct *work)
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{
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struct input_polled_dev *dev =
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container_of(work, struct input_polled_dev, work.work);
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dev->poll(dev);
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queue_delayed_work(polldev_wq, &dev->work,
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msecs_to_jiffies(dev->poll_interval));
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}
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static int input_open_polled_device(struct input_dev *input)
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{
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struct input_polled_dev *dev = input->private;
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int error;
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unsigned long ticks;
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error = input_polldev_start_workqueue();
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if (error)
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return error;
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if (dev->flush)
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dev->flush(dev);
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ticks = msecs_to_jiffies(dev->poll_interval);
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if (ticks >= HZ)
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ticks = round_jiffies(ticks);
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queue_delayed_work(polldev_wq, &dev->work, ticks);
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return 0;
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}
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static void input_close_polled_device(struct input_dev *input)
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{
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struct input_polled_dev *dev = input->private;
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cancel_rearming_delayed_workqueue(polldev_wq, &dev->work);
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input_polldev_stop_workqueue();
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}
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/**
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* input_allocate_polled_device - allocated memory polled device
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*
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* The function allocates memory for a polled device and also
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* for an input device associated with this polled device.
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*/
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struct input_polled_dev *input_allocate_polled_device(void)
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{
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struct input_polled_dev *dev;
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dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
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if (!dev)
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return NULL;
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dev->input = input_allocate_device();
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if (!dev->input) {
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kfree(dev);
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return NULL;
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}
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return dev;
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}
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EXPORT_SYMBOL(input_allocate_polled_device);
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/**
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* input_free_polled_device - free memory allocated for polled device
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* @dev: device to free
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*
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* The function frees memory allocated for polling device and drops
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* reference to the associated input device (if present).
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*/
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void input_free_polled_device(struct input_polled_dev *dev)
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{
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if (dev) {
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input_free_device(dev->input);
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kfree(dev);
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}
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}
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EXPORT_SYMBOL(input_free_polled_device);
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/**
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* input_register_polled_device - register polled device
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* @dev: device to register
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*
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* The function registers previously initialized polled input device
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* with input layer. The device should be allocated with call to
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* input_allocate_polled_device(). Callers should also set up poll()
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* method and set up capabilities (id, name, phys, bits) of the
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* corresponing input_dev structure.
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*/
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int input_register_polled_device(struct input_polled_dev *dev)
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{
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struct input_dev *input = dev->input;
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INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
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if (!dev->poll_interval)
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dev->poll_interval = 500;
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input->private = dev;
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input->open = input_open_polled_device;
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input->close = input_close_polled_device;
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return input_register_device(input);
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}
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EXPORT_SYMBOL(input_register_polled_device);
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/**
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* input_unregister_polled_device - unregister polled device
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* @dev: device to unregister
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*
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* The function unregisters previously registered polled input
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* device from input layer. Polling is stopped and device is
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* ready to be freed with call to input_free_polled_device().
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* Callers should not attempt to access dev->input pointer
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* after calling this function.
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*/
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void input_unregister_polled_device(struct input_polled_dev *dev)
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{
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input_unregister_device(dev->input);
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dev->input = NULL;
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}
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EXPORT_SYMBOL(input_unregister_polled_device);
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