projects/linux·blob v2.6.33 · refs

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