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/mutex.h>
13 #include <linux/input-polldev.h>
15 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
16 MODULE_DESCRIPTION("Generic implementation of a polled input device");
17 MODULE_LICENSE("GPL v2");
18 MODULE_VERSION("0.1");
20 static DEFINE_MUTEX(polldev_mutex);
21 static int polldev_users;
22 static struct workqueue_struct *polldev_wq;
24 static int input_polldev_start_workqueue(void)
28 retval = mutex_lock_interruptible(&polldev_mutex);
33 polldev_wq = create_singlethread_workqueue("ipolldevd");
35 printk(KERN_ERR "input-polldev: failed to create "
36 "ipolldevd workqueue\n");
45 mutex_unlock(&polldev_mutex);
49 static void input_polldev_stop_workqueue(void)
51 mutex_lock(&polldev_mutex);
54 destroy_workqueue(polldev_wq);
56 mutex_unlock(&polldev_mutex);
59 static void input_polldev_queue_work(struct input_polled_dev *dev)
63 delay = msecs_to_jiffies(dev->poll_interval);
65 delay = round_jiffies_relative(delay);
67 queue_delayed_work(polldev_wq, &dev->work, delay);
70 static void input_polled_device_work(struct work_struct *work)
72 struct input_polled_dev *dev =
73 container_of(work, struct input_polled_dev, work.work);
76 input_polldev_queue_work(dev);
79 static int input_open_polled_device(struct input_dev *input)
81 struct input_polled_dev *dev = input_get_drvdata(input);
84 error = input_polldev_start_workqueue();
91 queue_delayed_work(polldev_wq, &dev->work, 0);
96 static void input_close_polled_device(struct input_dev *input)
98 struct input_polled_dev *dev = input_get_drvdata(input);
100 cancel_delayed_work_sync(&dev->work);
101 input_polldev_stop_workqueue();
107 /* SYSFS interface */
109 static ssize_t input_polldev_get_poll(struct device *dev,
110 struct device_attribute *attr, char *buf)
112 struct input_polled_dev *polldev = dev_get_drvdata(dev);
114 return sprintf(buf, "%d\n", polldev->poll_interval);
117 static ssize_t input_polldev_set_poll(struct device *dev,
118 struct device_attribute *attr, const char *buf,
121 struct input_polled_dev *polldev = dev_get_drvdata(dev);
122 struct input_dev *input = polldev->input;
123 unsigned long interval;
125 if (strict_strtoul(buf, 0, &interval))
128 if (interval < polldev->poll_interval_min)
131 if (interval > polldev->poll_interval_max)
134 mutex_lock(&input->mutex);
136 polldev->poll_interval = interval;
139 cancel_delayed_work_sync(&polldev->work);
140 if (polldev->poll_interval > 0)
141 input_polldev_queue_work(polldev);
144 mutex_unlock(&input->mutex);
149 static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
150 input_polldev_set_poll);
153 static ssize_t input_polldev_get_max(struct device *dev,
154 struct device_attribute *attr, char *buf)
156 struct input_polled_dev *polldev = dev_get_drvdata(dev);
158 return sprintf(buf, "%d\n", polldev->poll_interval_max);
161 static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
163 static ssize_t input_polldev_get_min(struct device *dev,
164 struct device_attribute *attr, char *buf)
166 struct input_polled_dev *polldev = dev_get_drvdata(dev);
168 return sprintf(buf, "%d\n", polldev->poll_interval_min);
171 static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
173 static struct attribute *sysfs_attrs[] = {
180 static struct attribute_group input_polldev_attribute_group = {
185 * input_allocate_polled_device - allocated memory polled device
187 * The function allocates memory for a polled device and also
188 * for an input device associated with this polled device.
190 struct input_polled_dev *input_allocate_polled_device(void)
192 struct input_polled_dev *dev;
194 dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
198 dev->input = input_allocate_device();
206 EXPORT_SYMBOL(input_allocate_polled_device);
209 * input_free_polled_device - free memory allocated for polled device
210 * @dev: device to free
212 * The function frees memory allocated for polling device and drops
213 * reference to the associated input device (if present).
215 void input_free_polled_device(struct input_polled_dev *dev)
218 input_free_device(dev->input);
222 EXPORT_SYMBOL(input_free_polled_device);
225 * input_register_polled_device - register polled device
226 * @dev: device to register
228 * The function registers previously initialized polled input device
229 * with input layer. The device should be allocated with call to
230 * input_allocate_polled_device(). Callers should also set up poll()
231 * method and set up capabilities (id, name, phys, bits) of the
232 * corresponing input_dev structure.
234 int input_register_polled_device(struct input_polled_dev *dev)
236 struct input_dev *input = dev->input;
239 input_set_drvdata(input, dev);
240 INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
241 if (!dev->poll_interval)
242 dev->poll_interval = 500;
243 if (!dev->poll_interval_max)
244 dev->poll_interval_max = dev->poll_interval;
245 input->open = input_open_polled_device;
246 input->close = input_close_polled_device;
248 error = input_register_device(input);
252 error = sysfs_create_group(&input->dev.kobj,
253 &input_polldev_attribute_group);
255 input_unregister_device(input);
261 EXPORT_SYMBOL(input_register_polled_device);
264 * input_unregister_polled_device - unregister polled device
265 * @dev: device to unregister
267 * The function unregisters previously registered polled input
268 * device from input layer. Polling is stopped and device is
269 * ready to be freed with call to input_free_polled_device().
270 * Callers should not attempt to access dev->input pointer
271 * after calling this function.
273 void input_unregister_polled_device(struct input_polled_dev *dev)
275 sysfs_remove_group(&dev->input->dev.kobj,
276 &input_polldev_attribute_group);
278 input_unregister_device(dev->input);
281 EXPORT_SYMBOL(input_unregister_polled_device);