projects/linux·blob v2.6.36 · refs

297 lines · 7.1 KiB

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/slab.h>
13#include <linux/mutex.h>
14#include <linux/input-polldev.h>
15
16MODULE_AUTHOR("Dmitry Torokhov <[email protected]>");
17MODULE_DESCRIPTION("Generic implementation of a polled input device");
18MODULE_LICENSE("GPL v2");
19MODULE_VERSION("0.1");
20
21static DEFINE_MUTEX(polldev_mutex);
22static int polldev_users;
23static struct workqueue_struct *polldev_wq;
24
25static int input_polldev_start_workqueue(void)
26{
27 int retval;
28
29 retval = mutex_lock_interruptible(&polldev_mutex);
30 if (retval)
31 return retval;
32
33 if (!polldev_users) {
34 polldev_wq = create_singlethread_workqueue("ipolldevd");
35 if (!polldev_wq) {
36 printk(KERN_ERR "input-polldev: failed to create "
37 "ipolldevd workqueue\n");
38 retval = -ENOMEM;
39 goto out;
40 }
41 }
42
43 polldev_users++;
44
45 out:
46 mutex_unlock(&polldev_mutex);
47 return retval;
48}
49
50static void input_polldev_stop_workqueue(void)
51{
52 mutex_lock(&polldev_mutex);
53
54 if (!--polldev_users)
55 destroy_workqueue(polldev_wq);
56
57 mutex_unlock(&polldev_mutex);
58}
59
60static void input_polldev_queue_work(struct input_polled_dev *dev)
61{
62 unsigned long delay;
63
64 delay = msecs_to_jiffies(dev->poll_interval);
65 if (delay >= HZ)
66 delay = round_jiffies_relative(delay);
67
68 queue_delayed_work(polldev_wq, &dev->work, delay);
69}
70
71static void input_polled_device_work(struct work_struct *work)
72{
73 struct input_polled_dev *dev =
74 container_of(work, struct input_polled_dev, work.work);
75
76 dev->poll(dev);
77 input_polldev_queue_work(dev);
78}
79
80static int input_open_polled_device(struct input_dev *input)
81{
82 struct input_polled_dev *dev = input_get_drvdata(input);
83 int error;
84
85 error = input_polldev_start_workqueue();
86 if (error)
87 return error;
88
89 if (dev->open)
90 dev->open(dev);
91
92 /* Only start polling if polling is enabled */
93 if (dev->poll_interval > 0)
94 queue_delayed_work(polldev_wq, &dev->work, 0);
95
96 return 0;
97}
98
99static void input_close_polled_device(struct input_dev *input)
100{
101 struct input_polled_dev *dev = input_get_drvdata(input);
102
103 cancel_delayed_work_sync(&dev->work);
104 /*
105 * Clean up work struct to remove references to the workqueue.
106 * It may be destroyed by the next call. This causes problems
107 * at next device open-close in case of poll_interval == 0.
108 */
109 INIT_DELAYED_WORK(&dev->work, dev->work.work.func);
110 input_polldev_stop_workqueue();
111
112 if (dev->close)
113 dev->close(dev);
114}
115
116/* SYSFS interface */
117
118static ssize_t input_polldev_get_poll(struct device *dev,
119 struct device_attribute *attr, char *buf)
120{
121 struct input_polled_dev *polldev = dev_get_drvdata(dev);
122
123 return sprintf(buf, "%d\n", polldev->poll_interval);
124}
125
126static ssize_t input_polldev_set_poll(struct device *dev,
127 struct device_attribute *attr, const char *buf,
128 size_t count)
129{
130 struct input_polled_dev *polldev = dev_get_drvdata(dev);
131 struct input_dev *input = polldev->input;
132 unsigned long interval;
133
134 if (strict_strtoul(buf, 0, &interval))
135 return -EINVAL;
136
137 if (interval < polldev->poll_interval_min)
138 return -EINVAL;
139
140 if (interval > polldev->poll_interval_max)
141 return -EINVAL;
142
143 mutex_lock(&input->mutex);
144
145 polldev->poll_interval = interval;
146
147 if (input->users) {
148 cancel_delayed_work_sync(&polldev->work);
149 if (polldev->poll_interval > 0)
150 input_polldev_queue_work(polldev);
151 }
152
153 mutex_unlock(&input->mutex);
154
155 return count;
156}
157
158static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
159 input_polldev_set_poll);
160
161
162static ssize_t input_polldev_get_max(struct device *dev,
163 struct device_attribute *attr, char *buf)
164{
165 struct input_polled_dev *polldev = dev_get_drvdata(dev);
166
167 return sprintf(buf, "%d\n", polldev->poll_interval_max);
168}
169
170static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
171
172static ssize_t input_polldev_get_min(struct device *dev,
173 struct device_attribute *attr, char *buf)
174{
175 struct input_polled_dev *polldev = dev_get_drvdata(dev);
176
177 return sprintf(buf, "%d\n", polldev->poll_interval_min);
178}
179
180static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
181
182static struct attribute *sysfs_attrs[] = {
183 &dev_attr_poll.attr,
184 &dev_attr_max.attr,
185 &dev_attr_min.attr,
186 NULL
187};
188
189static struct attribute_group input_polldev_attribute_group = {
190 .attrs = sysfs_attrs
191};
192
193/**
194 * input_allocate_polled_device - allocated memory polled device
195 *
196 * The function allocates memory for a polled device and also
197 * for an input device associated with this polled device.
198 */
199struct input_polled_dev *input_allocate_polled_device(void)
200{
201 struct input_polled_dev *dev;
202
203 dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
204 if (!dev)
205 return NULL;
206
207 dev->input = input_allocate_device();
208 if (!dev->input) {
209 kfree(dev);
210 return NULL;
211 }
212
213 return dev;
214}
215EXPORT_SYMBOL(input_allocate_polled_device);
216
217/**
218 * input_free_polled_device - free memory allocated for polled device
219 * @dev: device to free
220 *
221 * The function frees memory allocated for polling device and drops
222 * reference to the associated input device.
223 */
224void input_free_polled_device(struct input_polled_dev *dev)
225{
226 if (dev) {
227 input_free_device(dev->input);
228 kfree(dev);
229 }
230}
231EXPORT_SYMBOL(input_free_polled_device);
232
233/**
234 * input_register_polled_device - register polled device
235 * @dev: device to register
236 *
237 * The function registers previously initialized polled input device
238 * with input layer. The device should be allocated with call to
239 * input_allocate_polled_device(). Callers should also set up poll()
240 * method and set up capabilities (id, name, phys, bits) of the
241 * corresponing input_dev structure.
242 */
243int input_register_polled_device(struct input_polled_dev *dev)
244{
245 struct input_dev *input = dev->input;
246 int error;
247
248 input_set_drvdata(input, dev);
249 INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
250 if (!dev->poll_interval)
251 dev->poll_interval = 500;
252 if (!dev->poll_interval_max)
253 dev->poll_interval_max = dev->poll_interval;
254 input->open = input_open_polled_device;
255 input->close = input_close_polled_device;
256
257 error = input_register_device(input);
258 if (error)
259 return error;
260
261 error = sysfs_create_group(&input->dev.kobj,
262 &input_polldev_attribute_group);
263 if (error) {
264 input_unregister_device(input);
265 return error;
266 }
267
268 /*
269 * Take extra reference to the underlying input device so
270 * that it survives call to input_unregister_polled_device()
271 * and is deleted only after input_free_polled_device()
272 * has been invoked. This is needed to ease task of freeing
273 * sparse keymaps.
274 */
275 input_get_device(input);
276
277 return 0;
278}
279EXPORT_SYMBOL(input_register_polled_device);
280
281/**
282 * input_unregister_polled_device - unregister polled device
283 * @dev: device to unregister
284 *
285 * The function unregisters previously registered polled input
286 * device from input layer. Polling is stopped and device is
287 * ready to be freed with call to input_free_polled_device().
288 */
289void input_unregister_polled_device(struct input_polled_dev *dev)
290{
291 sysfs_remove_group(&dev->input->dev.kobj,
292 &input_polldev_attribute_group);
293
294 input_unregister_device(dev->input);
295}
296EXPORT_SYMBOL(input_unregister_polled_device);
297