Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1/*
2 * Generic implementation of a polled input device
3
4 * Copyright (c) 2007 Dmitry Torokhov
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 */
10
11#include <linux/jiffies.h>
12#include <linux/mutex.h>
13#include <linux/input-polldev.h>
14
15static DEFINE_MUTEX(polldev_mutex);
16static int polldev_users;
17static struct workqueue_struct *polldev_wq;
18
19static int input_polldev_start_workqueue(void)
20{
21 int retval;
22
23 retval = mutex_lock_interruptible(&polldev_mutex);
24 if (retval)
25 return retval;
26
27 if (!polldev_users) {
28 polldev_wq = create_singlethread_workqueue("ipolldevd");
29 if (!polldev_wq) {
30 printk(KERN_ERR "input-polldev: failed to create "
31 "ipolldevd workqueue\n");
32 retval = -ENOMEM;
33 goto out;
34 }
35 }
36
37 polldev_users++;
38
39 out:
40 mutex_unlock(&polldev_mutex);
41 return retval;
42}
43
44static void input_polldev_stop_workqueue(void)
45{
46 mutex_lock(&polldev_mutex);
47
48 if (!--polldev_users)
49 destroy_workqueue(polldev_wq);
50
51 mutex_unlock(&polldev_mutex);
52}
53
54static void input_polled_device_work(struct work_struct *work)
55{
56 struct input_polled_dev *dev =
57 container_of(work, struct input_polled_dev, work.work);
58
59 dev->poll(dev);
60 queue_delayed_work(polldev_wq, &dev->work,
61 msecs_to_jiffies(dev->poll_interval));
62}
63
64static int input_open_polled_device(struct input_dev *input)
65{
66 struct input_polled_dev *dev = input->private;
67 int error;
68
69 error = input_polldev_start_workqueue();
70 if (error)
71 return error;
72
73 if (dev->flush)
74 dev->flush(dev);
75
76 queue_delayed_work(polldev_wq, &dev->work,
77 msecs_to_jiffies(dev->poll_interval));
78
79 return 0;
80}
81
82static void input_close_polled_device(struct input_dev *input)
83{
84 struct input_polled_dev *dev = input->private;
85
86 cancel_rearming_delayed_workqueue(polldev_wq, &dev->work);
87 input_polldev_stop_workqueue();
88}
89
90/**
91 * input_allocate_polled_device - allocated memory polled device
92 *
93 * The function allocates memory for a polled device and also
94 * for an input device associated with this polled device.
95 */
96struct input_polled_dev *input_allocate_polled_device(void)
97{
98 struct input_polled_dev *dev;
99
100 dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
101 if (!dev)
102 return NULL;
103
104 dev->input = input_allocate_device();
105 if (!dev->input) {
106 kfree(dev);
107 return NULL;
108 }
109
110 return dev;
111}
112EXPORT_SYMBOL(input_allocate_polled_device);
113
114/**
115 * input_free_polled_device - free memory allocated for polled device
116 * @dev: device to free
117 *
118 * The function frees memory allocated for polling device and drops
119 * reference to the associated input device (if present).
120 */
121void input_free_polled_device(struct input_polled_dev *dev)
122{
123 if (dev) {
124 input_free_device(dev->input);
125 kfree(dev);
126 }
127}
128EXPORT_SYMBOL(input_free_polled_device);
129
130/**
131 * input_register_polled_device - register polled device
132 * @dev: device to register
133 *
134 * The function registers previously initialized polled input device
135 * with input layer. The device should be allocated with call to
136 * input_allocate_polled_device(). Callers should also set up poll()
137 * method and set up capabilities (id, name, phys, bits) of the
138 * corresponing input_dev structure.
139 */
140int input_register_polled_device(struct input_polled_dev *dev)
141{
142 struct input_dev *input = dev->input;
143
144 INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
145 if (!dev->poll_interval)
146 dev->poll_interval = 500;
147 input->private = dev;
148 input->open = input_open_polled_device;
149 input->close = input_close_polled_device;
150
151 return input_register_device(input);
152}
153EXPORT_SYMBOL(input_register_polled_device);
154
155/**
156 * input_unregister_polled_device - unregister polled device
157 * @dev: device to unregister
158 *
159 * The function unregisters previously registered polled input
160 * device from input layer. Polling is stopped and device is
161 * ready to be freed with call to input_free_polled_device().
162 * Callers should not attempt to access dev->input pointer
163 * after calling this function.
164 */
165void input_unregister_polled_device(struct input_polled_dev *dev)
166{
167 input_unregister_device(dev->input);
168 dev->input = NULL;
169}
170EXPORT_SYMBOL(input_unregister_polled_device);
171