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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/jiffies.h>
14 #include <linux/slab.h>
15 #include <linux/mutex.h>
16 #include <linux/workqueue.h>
17 #include <linux/module.h>
18 #include <linux/input-polldev.h>
20 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
21 MODULE_DESCRIPTION("Generic implementation of a polled input device");
22 MODULE_LICENSE("GPL v2");
23 MODULE_VERSION("0.1");
25 static void input_polldev_queue_work(struct input_polled_dev *dev)
29 delay = msecs_to_jiffies(dev->poll_interval);
31 delay = round_jiffies_relative(delay);
33 queue_delayed_work(system_freezable_wq, &dev->work, delay);
36 static void input_polled_device_work(struct work_struct *work)
38 struct input_polled_dev *dev =
39 container_of(work, struct input_polled_dev, work.work);
42 input_polldev_queue_work(dev);
45 static int input_open_polled_device(struct input_dev *input)
47 struct input_polled_dev *dev = input_get_drvdata(input);
52 /* Only start polling if polling is enabled */
53 if (dev->poll_interval > 0) {
55 input_polldev_queue_work(dev);
61 static void input_close_polled_device(struct input_dev *input)
63 struct input_polled_dev *dev = input_get_drvdata(input);
65 cancel_delayed_work_sync(&dev->work);
73 static ssize_t input_polldev_get_poll(struct device *dev,
74 struct device_attribute *attr, char *buf)
76 struct input_polled_dev *polldev = dev_get_drvdata(dev);
78 return sprintf(buf, "%d\n", polldev->poll_interval);
81 static ssize_t input_polldev_set_poll(struct device *dev,
82 struct device_attribute *attr, const char *buf,
85 struct input_polled_dev *polldev = dev_get_drvdata(dev);
86 struct input_dev *input = polldev->input;
87 unsigned long interval;
89 if (strict_strtoul(buf, 0, &interval))
92 if (interval < polldev->poll_interval_min)
95 if (interval > polldev->poll_interval_max)
98 mutex_lock(&input->mutex);
100 polldev->poll_interval = interval;
103 cancel_delayed_work_sync(&polldev->work);
104 if (polldev->poll_interval > 0)
105 input_polldev_queue_work(polldev);
108 mutex_unlock(&input->mutex);
113 static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
114 input_polldev_set_poll);
117 static ssize_t input_polldev_get_max(struct device *dev,
118 struct device_attribute *attr, char *buf)
120 struct input_polled_dev *polldev = dev_get_drvdata(dev);
122 return sprintf(buf, "%d\n", polldev->poll_interval_max);
125 static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
127 static ssize_t input_polldev_get_min(struct device *dev,
128 struct device_attribute *attr, char *buf)
130 struct input_polled_dev *polldev = dev_get_drvdata(dev);
132 return sprintf(buf, "%d\n", polldev->poll_interval_min);
135 static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
137 static struct attribute *sysfs_attrs[] = {
144 static struct attribute_group input_polldev_attribute_group = {
149 * input_allocate_polled_device - allocate memory for polled device
151 * The function allocates memory for a polled device and also
152 * for an input device associated with this polled device.
154 struct input_polled_dev *input_allocate_polled_device(void)
156 struct input_polled_dev *dev;
158 dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
162 dev->input = input_allocate_device();
170 EXPORT_SYMBOL(input_allocate_polled_device);
173 * input_free_polled_device - free memory allocated for polled device
174 * @dev: device to free
176 * The function frees memory allocated for polling device and drops
177 * reference to the associated input device.
179 void input_free_polled_device(struct input_polled_dev *dev)
182 input_free_device(dev->input);
186 EXPORT_SYMBOL(input_free_polled_device);
189 * input_register_polled_device - register polled device
190 * @dev: device to register
192 * The function registers previously initialized polled input device
193 * with input layer. The device should be allocated with call to
194 * input_allocate_polled_device(). Callers should also set up poll()
195 * method and set up capabilities (id, name, phys, bits) of the
196 * corresponding input_dev structure.
198 int input_register_polled_device(struct input_polled_dev *dev)
200 struct input_dev *input = dev->input;
203 input_set_drvdata(input, dev);
204 INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
205 if (!dev->poll_interval)
206 dev->poll_interval = 500;
207 if (!dev->poll_interval_max)
208 dev->poll_interval_max = dev->poll_interval;
209 input->open = input_open_polled_device;
210 input->close = input_close_polled_device;
212 error = input_register_device(input);
216 error = sysfs_create_group(&input->dev.kobj,
217 &input_polldev_attribute_group);
219 input_unregister_device(input);
224 * Take extra reference to the underlying input device so
225 * that it survives call to input_unregister_polled_device()
226 * and is deleted only after input_free_polled_device()
227 * has been invoked. This is needed to ease task of freeing
230 input_get_device(input);
234 EXPORT_SYMBOL(input_register_polled_device);
237 * input_unregister_polled_device - unregister polled device
238 * @dev: device to unregister
240 * The function unregisters previously registered polled input
241 * device from input layer. Polling is stopped and device is
242 * ready to be freed with call to input_free_polled_device().
244 void input_unregister_polled_device(struct input_polled_dev *dev)
246 sysfs_remove_group(&dev->input->dev.kobj,
247 &input_polldev_attribute_group);
249 input_unregister_device(dev->input);
251 EXPORT_SYMBOL(input_unregister_polled_device);