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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 12
 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>
 19
 20MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
 21MODULE_DESCRIPTION("Generic implementation of a polled input device");
 22MODULE_LICENSE("GPL v2");
 23
 24static void input_polldev_queue_work(struct input_polled_dev *dev)
 25{
 26	unsigned long delay;
 27
 28	delay = msecs_to_jiffies(dev->poll_interval);
 29	if (delay >= HZ)
 30		delay = round_jiffies_relative(delay);
 31
 32	queue_delayed_work(system_freezable_wq, &dev->work, delay);
 33}
 34
 35static void input_polled_device_work(struct work_struct *work)
 36{
 37	struct input_polled_dev *dev =
 38		container_of(work, struct input_polled_dev, work.work);
 39
 40	dev->poll(dev);
 41	input_polldev_queue_work(dev);
 42}
 43
 44static int input_open_polled_device(struct input_dev *input)
 45{
 46	struct input_polled_dev *dev = input_get_drvdata(input);
 47
 48	if (dev->open)
 49		dev->open(dev);
 50
 51	/* Only start polling if polling is enabled */
 52	if (dev->poll_interval > 0) {
 53		dev->poll(dev);
 54		input_polldev_queue_work(dev);
 55	}
 56
 57	return 0;
 58}
 59
 60static void input_close_polled_device(struct input_dev *input)
 61{
 62	struct input_polled_dev *dev = input_get_drvdata(input);
 63
 64	cancel_delayed_work_sync(&dev->work);
 65
 66	if (dev->close)
 67		dev->close(dev);
 68}
 69
 70/* SYSFS interface */
 71
 72static ssize_t input_polldev_get_poll(struct device *dev,
 73				      struct device_attribute *attr, char *buf)
 74{
 75	struct input_polled_dev *polldev = dev_get_drvdata(dev);
 76
 77	return sprintf(buf, "%d\n", polldev->poll_interval);
 78}
 79
 80static ssize_t input_polldev_set_poll(struct device *dev,
 81				struct device_attribute *attr, const char *buf,
 82				size_t count)
 83{
 84	struct input_polled_dev *polldev = dev_get_drvdata(dev);
 85	struct input_dev *input = polldev->input;
 86	unsigned int interval;
 87	int err;
 88
 89	err = kstrtouint(buf, 0, &interval);
 90	if (err)
 91		return err;
 92
 93	if (interval < polldev->poll_interval_min)
 94		return -EINVAL;
 95
 96	if (interval > polldev->poll_interval_max)
 97		return -EINVAL;
 98
 99	mutex_lock(&input->mutex);
100
101	polldev->poll_interval = interval;
102
103	if (input->users) {
104		cancel_delayed_work_sync(&polldev->work);
105		if (polldev->poll_interval > 0)
106			input_polldev_queue_work(polldev);
107	}
108
109	mutex_unlock(&input->mutex);
110
111	return count;
112}
113
114static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
115					    input_polldev_set_poll);
116
117
118static ssize_t input_polldev_get_max(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_max);
124}
125
126static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
127
128static ssize_t input_polldev_get_min(struct device *dev,
129				     struct device_attribute *attr, char *buf)
130{
131	struct input_polled_dev *polldev = dev_get_drvdata(dev);
132
133	return sprintf(buf, "%d\n", polldev->poll_interval_min);
134}
135
136static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
137
138static struct attribute *sysfs_attrs[] = {
139	&dev_attr_poll.attr,
140	&dev_attr_max.attr,
141	&dev_attr_min.attr,
142	NULL
143};
144
145static struct attribute_group input_polldev_attribute_group = {
146	.attrs = sysfs_attrs
147};
148
149static const struct attribute_group *input_polldev_attribute_groups[] = {
150	&input_polldev_attribute_group,
151	NULL
152};
153
154/**
155 * input_allocate_polled_device - allocate memory for polled device
156 *
157 * The function allocates memory for a polled device and also
158 * for an input device associated with this polled device.
159 */
160struct input_polled_dev *input_allocate_polled_device(void)
161{
162	struct input_polled_dev *dev;
163
164	dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
165	if (!dev)
166		return NULL;
167
168	dev->input = input_allocate_device();
169	if (!dev->input) {
170		kfree(dev);
171		return NULL;
172	}
173
174	return dev;
175}
176EXPORT_SYMBOL(input_allocate_polled_device);
177
178struct input_polled_devres {
179	struct input_polled_dev *polldev;
180};
181
182static int devm_input_polldev_match(struct device *dev, void *res, void *data)
183{
184	struct input_polled_devres *devres = res;
185
186	return devres->polldev == data;
187}
188
189static void devm_input_polldev_release(struct device *dev, void *res)
190{
191	struct input_polled_devres *devres = res;
192	struct input_polled_dev *polldev = devres->polldev;
193
194	dev_dbg(dev, "%s: dropping reference/freeing %s\n",
195		__func__, dev_name(&polldev->input->dev));
196
197	input_put_device(polldev->input);
198	kfree(polldev);
199}
200
201static void devm_input_polldev_unregister(struct device *dev, void *res)
202{
203	struct input_polled_devres *devres = res;
204	struct input_polled_dev *polldev = devres->polldev;
205
206	dev_dbg(dev, "%s: unregistering device %s\n",
207		__func__, dev_name(&polldev->input->dev));
208	input_unregister_device(polldev->input);
209
210	/*
211	 * Note that we are still holding extra reference to the input
212	 * device so it will stick around until devm_input_polldev_release()
213	 * is called.
214	 */
215}
216
217/**
218 * devm_input_allocate_polled_device - allocate managed polled device
219 * @dev: device owning the polled device being created
220 *
221 * Returns prepared &struct input_polled_dev or %NULL.
222 *
223 * Managed polled input devices do not need to be explicitly unregistered
224 * or freed as it will be done automatically when owner device unbinds
225 * from * its driver (or binding fails). Once such managed polled device
226 * is allocated, it is ready to be set up and registered in the same
227 * fashion as regular polled input devices (using
228 * input_register_polled_device() function).
229 *
230 * If you want to manually unregister and free such managed polled devices,
231 * it can be still done by calling input_unregister_polled_device() and
232 * input_free_polled_device(), although it is rarely needed.
233 *
234 * NOTE: the owner device is set up as parent of input device and users
235 * should not override it.
236 */
237struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev)
238{
239	struct input_polled_dev *polldev;
240	struct input_polled_devres *devres;
241
242	devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),
243			      GFP_KERNEL);
244	if (!devres)
245		return NULL;
246
247	polldev = input_allocate_polled_device();
248	if (!polldev) {
249		devres_free(devres);
250		return NULL;
251	}
252
253	polldev->input->dev.parent = dev;
254	polldev->devres_managed = true;
255
256	devres->polldev = polldev;
257	devres_add(dev, devres);
258
259	return polldev;
260}
261EXPORT_SYMBOL(devm_input_allocate_polled_device);
262
263/**
264 * input_free_polled_device - free memory allocated for polled device
265 * @dev: device to free
266 *
267 * The function frees memory allocated for polling device and drops
268 * reference to the associated input device.
269 */
270void input_free_polled_device(struct input_polled_dev *dev)
271{
272	if (dev) {
273		if (dev->devres_managed)
274			WARN_ON(devres_destroy(dev->input->dev.parent,
275						devm_input_polldev_release,
276						devm_input_polldev_match,
277						dev));
278		input_put_device(dev->input);
279		kfree(dev);
280	}
281}
282EXPORT_SYMBOL(input_free_polled_device);
283
284/**
285 * input_register_polled_device - register polled device
286 * @dev: device to register
287 *
288 * The function registers previously initialized polled input device
289 * with input layer. The device should be allocated with call to
290 * input_allocate_polled_device(). Callers should also set up poll()
291 * method and set up capabilities (id, name, phys, bits) of the
292 * corresponding input_dev structure.
293 */
294int input_register_polled_device(struct input_polled_dev *dev)
295{
296	struct input_polled_devres *devres = NULL;
297	struct input_dev *input = dev->input;
298	int error;
299
300	if (dev->devres_managed) {
301		devres = devres_alloc(devm_input_polldev_unregister,
302				      sizeof(*devres), GFP_KERNEL);
303		if (!devres)
304			return -ENOMEM;
305
306		devres->polldev = dev;
307	}
308
309	input_set_drvdata(input, dev);
310	INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
311
312	if (!dev->poll_interval)
313		dev->poll_interval = 500;
314	if (!dev->poll_interval_max)
315		dev->poll_interval_max = dev->poll_interval;
316
317	input->open = input_open_polled_device;
318	input->close = input_close_polled_device;
319
320	input->dev.groups = input_polldev_attribute_groups;
321
322	error = input_register_device(input);
323	if (error) {
324		devres_free(devres);
325		return error;
326	}
327
328	/*
329	 * Take extra reference to the underlying input device so
330	 * that it survives call to input_unregister_polled_device()
331	 * and is deleted only after input_free_polled_device()
332	 * has been invoked. This is needed to ease task of freeing
333	 * sparse keymaps.
334	 */
335	input_get_device(input);
336
337	if (dev->devres_managed) {
338		dev_dbg(input->dev.parent, "%s: registering %s with devres.\n",
339			__func__, dev_name(&input->dev));
340		devres_add(input->dev.parent, devres);
341	}
342
343	return 0;
344}
345EXPORT_SYMBOL(input_register_polled_device);
346
347/**
348 * input_unregister_polled_device - unregister polled device
349 * @dev: device to unregister
350 *
351 * The function unregisters previously registered polled input
352 * device from input layer. Polling is stopped and device is
353 * ready to be freed with call to input_free_polled_device().
354 */
355void input_unregister_polled_device(struct input_polled_dev *dev)
356{
357	if (dev->devres_managed)
358		WARN_ON(devres_destroy(dev->input->dev.parent,
359					devm_input_polldev_unregister,
360					devm_input_polldev_match,
361					dev));
362
363	input_unregister_device(dev->input);
364}
365EXPORT_SYMBOL(input_unregister_polled_device);