2 * Generic implementation of a polled input device
4 * Copyright (c) 2007 Dmitry Torokhov
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.
11 #include <linux/jiffies.h>
12 #include <linux/slab.h>
13 #include <linux/mutex.h>
14 #include <linux/input-polldev.h>
16 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
17 MODULE_DESCRIPTION("Generic implementation of a polled input device");
18 MODULE_LICENSE("GPL v2");
19 MODULE_VERSION("0.1");
21 static DEFINE_MUTEX(polldev_mutex);
22 static int polldev_users;
23 static struct workqueue_struct *polldev_wq;
25 static int input_polldev_start_workqueue(void)
29 retval = mutex_lock_interruptible(&polldev_mutex);
34 polldev_wq = create_singlethread_workqueue("ipolldevd");
36 printk(KERN_ERR "input-polldev: failed to create "
37 "ipolldevd workqueue\n");
46 mutex_unlock(&polldev_mutex);
50 static void input_polldev_stop_workqueue(void)
52 mutex_lock(&polldev_mutex);
55 destroy_workqueue(polldev_wq);
57 mutex_unlock(&polldev_mutex);
60 static void input_polldev_queue_work(struct input_polled_dev *dev)
64 delay = msecs_to_jiffies(dev->poll_interval);
66 delay = round_jiffies_relative(delay);
68 queue_delayed_work(polldev_wq, &dev->work, delay);
71 static void input_polled_device_work(struct work_struct *work)
73 struct input_polled_dev *dev =
74 container_of(work, struct input_polled_dev, work.work);
77 input_polldev_queue_work(dev);
80 static int input_open_polled_device(struct input_dev *input)
82 struct input_polled_dev *dev = input_get_drvdata(input);
85 error = input_polldev_start_workqueue();
92 /* Only start polling if polling is enabled */
93 if (dev->poll_interval > 0)
94 queue_delayed_work(polldev_wq, &dev->work, 0);
99 static void input_close_polled_device(struct input_dev *input)
101 struct input_polled_dev *dev = input_get_drvdata(input);
103 cancel_delayed_work_sync(&dev->work);
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.
109 INIT_DELAYED_WORK(&dev->work, dev->work.work.func);
110 input_polldev_stop_workqueue();
116 /* SYSFS interface */
118 static ssize_t input_polldev_get_poll(struct device *dev,
119 struct device_attribute *attr, char *buf)
121 struct input_polled_dev *polldev = dev_get_drvdata(dev);
123 return sprintf(buf, "%d\n", polldev->poll_interval);
126 static ssize_t input_polldev_set_poll(struct device *dev,
127 struct device_attribute *attr, const char *buf,
130 struct input_polled_dev *polldev = dev_get_drvdata(dev);
131 struct input_dev *input = polldev->input;
132 unsigned long interval;
134 if (strict_strtoul(buf, 0, &interval))
137 if (interval < polldev->poll_interval_min)
140 if (interval > polldev->poll_interval_max)
143 mutex_lock(&input->mutex);
145 polldev->poll_interval = interval;
148 cancel_delayed_work_sync(&polldev->work);
149 if (polldev->poll_interval > 0)
150 input_polldev_queue_work(polldev);
153 mutex_unlock(&input->mutex);
158 static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
159 input_polldev_set_poll);
162 static ssize_t input_polldev_get_max(struct device *dev,
163 struct device_attribute *attr, char *buf)
165 struct input_polled_dev *polldev = dev_get_drvdata(dev);
167 return sprintf(buf, "%d\n", polldev->poll_interval_max);
170 static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
172 static ssize_t input_polldev_get_min(struct device *dev,
173 struct device_attribute *attr, char *buf)
175 struct input_polled_dev *polldev = dev_get_drvdata(dev);
177 return sprintf(buf, "%d\n", polldev->poll_interval_min);
180 static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
182 static struct attribute *sysfs_attrs[] = {
189 static struct attribute_group input_polldev_attribute_group = {
194 * input_allocate_polled_device - allocated memory polled device
196 * The function allocates memory for a polled device and also
197 * for an input device associated with this polled device.
199 struct input_polled_dev *input_allocate_polled_device(void)
201 struct input_polled_dev *dev;
203 dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
207 dev->input = input_allocate_device();
215 EXPORT_SYMBOL(input_allocate_polled_device);
218 * input_free_polled_device - free memory allocated for polled device
219 * @dev: device to free
221 * The function frees memory allocated for polling device and drops
222 * reference to the associated input device.
224 void input_free_polled_device(struct input_polled_dev *dev)
227 input_free_device(dev->input);
231 EXPORT_SYMBOL(input_free_polled_device);
234 * input_register_polled_device - register polled device
235 * @dev: device to register
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.
243 int input_register_polled_device(struct input_polled_dev *dev)
245 struct input_dev *input = dev->input;
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;
257 error = input_register_device(input);
261 error = sysfs_create_group(&input->dev.kobj,
262 &input_polldev_attribute_group);
264 input_unregister_device(input);
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
275 input_get_device(input);
279 EXPORT_SYMBOL(input_register_polled_device);
282 * input_unregister_polled_device - unregister polled device
283 * @dev: device to unregister
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().
289 void input_unregister_polled_device(struct input_polled_dev *dev)
291 sysfs_remove_group(&dev->input->dev.kobj,
292 &input_polldev_attribute_group);
294 input_unregister_device(dev->input);
296 EXPORT_SYMBOL(input_unregister_polled_device);