1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Generic implementation of a polled input device
4
5 * Copyright (c) 2007 Dmitry Torokhov
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/jiffies.h>
11#include <linux/slab.h>
12#include <linux/mutex.h>
13#include <linux/workqueue.h>
14#include <linux/module.h>
15#include <linux/input-polldev.h>
16
17MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
18MODULE_DESCRIPTION("Generic implementation of a polled input device");
19MODULE_LICENSE("GPL v2");
20
21static void input_polldev_queue_work(struct input_polled_dev *dev)
22{
23	unsigned long delay;
24
25	delay = msecs_to_jiffies(dev->poll_interval);
26	if (delay >= HZ)
27		delay = round_jiffies_relative(delay);
28
29	queue_delayed_work(system_freezable_wq, &dev->work, delay);
30}
31
32static void input_polled_device_work(struct work_struct *work)
33{
34	struct input_polled_dev *dev =
35		container_of(work, struct input_polled_dev, work.work);
36
37	dev->poll(dev);
38	input_polldev_queue_work(dev);
39}
40
41static int input_open_polled_device(struct input_dev *input)
42{
43	struct input_polled_dev *dev = input_get_drvdata(input);
44
45	if (dev->open)
46		dev->open(dev);
47
48	/* Only start polling if polling is enabled */
49	if (dev->poll_interval > 0) {
50		dev->poll(dev);
51		input_polldev_queue_work(dev);
52	}
53
54	return 0;
55}
56
57static void input_close_polled_device(struct input_dev *input)
58{
59	struct input_polled_dev *dev = input_get_drvdata(input);
60
61	cancel_delayed_work_sync(&dev->work);
62
63	if (dev->close)
64		dev->close(dev);
65}
66
67/* SYSFS interface */
68
69static ssize_t input_polldev_get_poll(struct device *dev,
70				      struct device_attribute *attr, char *buf)
71{
72	struct input_polled_dev *polldev = dev_get_drvdata(dev);
73
74	return sprintf(buf, "%d\n", polldev->poll_interval);
75}
76
77static ssize_t input_polldev_set_poll(struct device *dev,
78				struct device_attribute *attr, const char *buf,
79				size_t count)
80{
81	struct input_polled_dev *polldev = dev_get_drvdata(dev);
82	struct input_dev *input = polldev->input;
83	unsigned int interval;
84	int err;
85
86	err = kstrtouint(buf, 0, &interval);
87	if (err)
88		return err;
89
90	if (interval < polldev->poll_interval_min)
91		return -EINVAL;
92
93	if (interval > polldev->poll_interval_max)
94		return -EINVAL;
95
96	mutex_lock(&input->mutex);
97
98	polldev->poll_interval = interval;
99
100	if (input->users) {
101		cancel_delayed_work_sync(&polldev->work);
102		if (polldev->poll_interval > 0)
103			input_polldev_queue_work(polldev);
104	}
105
106	mutex_unlock(&input->mutex);
107
108	return count;
109}
110
111static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
112					    input_polldev_set_poll);
113
114
115static ssize_t input_polldev_get_max(struct device *dev,
116				     struct device_attribute *attr, char *buf)
117{
118	struct input_polled_dev *polldev = dev_get_drvdata(dev);
119
120	return sprintf(buf, "%d\n", polldev->poll_interval_max);
121}
122
123static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
124
125static ssize_t input_polldev_get_min(struct device *dev,
126				     struct device_attribute *attr, char *buf)
127{
128	struct input_polled_dev *polldev = dev_get_drvdata(dev);
129
130	return sprintf(buf, "%d\n", polldev->poll_interval_min);
131}
132
133static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
134
135static struct attribute *sysfs_attrs[] = {
136	&dev_attr_poll.attr,
137	&dev_attr_max.attr,
138	&dev_attr_min.attr,
139	NULL
140};
141
142static struct attribute_group input_polldev_attribute_group = {
143	.attrs = sysfs_attrs
144};
145
146static const struct attribute_group *input_polldev_attribute_groups[] = {
147	&input_polldev_attribute_group,
148	NULL
149};
150
151/**
152 * input_allocate_polled_device - allocate memory for polled device
153 *
154 * The function allocates memory for a polled device and also
155 * for an input device associated with this polled device.
156 */
157struct input_polled_dev *input_allocate_polled_device(void)
158{
159	struct input_polled_dev *dev;
160
161	dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
162	if (!dev)
163		return NULL;
164
165	dev->input = input_allocate_device();
166	if (!dev->input) {
167		kfree(dev);
168		return NULL;
169	}
170
171	return dev;
172}
173EXPORT_SYMBOL(input_allocate_polled_device);
174
175struct input_polled_devres {
176	struct input_polled_dev *polldev;
177};
178
179static int devm_input_polldev_match(struct device *dev, void *res, void *data)
180{
181	struct input_polled_devres *devres = res;
182
183	return devres->polldev == data;
184}
185
186static void devm_input_polldev_release(struct device *dev, void *res)
187{
188	struct input_polled_devres *devres = res;
189	struct input_polled_dev *polldev = devres->polldev;
190
191	dev_dbg(dev, "%s: dropping reference/freeing %s\n",
192		__func__, dev_name(&polldev->input->dev));
193
194	input_put_device(polldev->input);
195	kfree(polldev);
196}
197
198static void devm_input_polldev_unregister(struct device *dev, void *res)
199{
200	struct input_polled_devres *devres = res;
201	struct input_polled_dev *polldev = devres->polldev;
202
203	dev_dbg(dev, "%s: unregistering device %s\n",
204		__func__, dev_name(&polldev->input->dev));
205	input_unregister_device(polldev->input);
206
207	/*
208	 * Note that we are still holding extra reference to the input
209	 * device so it will stick around until devm_input_polldev_release()
210	 * is called.
211	 */
212}
213
214/**
215 * devm_input_allocate_polled_device - allocate managed polled device
216 * @dev: device owning the polled device being created
217 *
218 * Returns prepared &struct input_polled_dev or %NULL.
219 *
220 * Managed polled input devices do not need to be explicitly unregistered
221 * or freed as it will be done automatically when owner device unbinds
222 * from * its driver (or binding fails). Once such managed polled device
223 * is allocated, it is ready to be set up and registered in the same
224 * fashion as regular polled input devices (using
225 * input_register_polled_device() function).
226 *
227 * If you want to manually unregister and free such managed polled devices,
228 * it can be still done by calling input_unregister_polled_device() and
229 * input_free_polled_device(), although it is rarely needed.
230 *
231 * NOTE: the owner device is set up as parent of input device and users
232 * should not override it.
233 */
234struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev)
235{
236	struct input_polled_dev *polldev;
237	struct input_polled_devres *devres;
238
239	devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),
240			      GFP_KERNEL);
241	if (!devres)
242		return NULL;
243
244	polldev = input_allocate_polled_device();
245	if (!polldev) {
246		devres_free(devres);
247		return NULL;
248	}
249
250	polldev->input->dev.parent = dev;
251	polldev->devres_managed = true;
252
253	devres->polldev = polldev;
254	devres_add(dev, devres);
255
256	return polldev;
257}
258EXPORT_SYMBOL(devm_input_allocate_polled_device);
259
260/**
261 * input_free_polled_device - free memory allocated for polled device
262 * @dev: device to free
263 *
264 * The function frees memory allocated for polling device and drops
265 * reference to the associated input device.
266 */
267void input_free_polled_device(struct input_polled_dev *dev)
268{
269	if (dev) {
270		if (dev->devres_managed)
271			WARN_ON(devres_destroy(dev->input->dev.parent,
272						devm_input_polldev_release,
273						devm_input_polldev_match,
274						dev));
275		input_put_device(dev->input);
276		kfree(dev);
277	}
278}
279EXPORT_SYMBOL(input_free_polled_device);
280
281/**
282 * input_register_polled_device - register polled device
283 * @dev: device to register
284 *
285 * The function registers previously initialized polled input device
286 * with input layer. The device should be allocated with call to
287 * input_allocate_polled_device(). Callers should also set up poll()
288 * method and set up capabilities (id, name, phys, bits) of the
289 * corresponding input_dev structure.
290 */
291int input_register_polled_device(struct input_polled_dev *dev)
292{
293	struct input_polled_devres *devres = NULL;
294	struct input_dev *input = dev->input;
295	int error;
296
297	if (dev->devres_managed) {
298		devres = devres_alloc(devm_input_polldev_unregister,
299				      sizeof(*devres), GFP_KERNEL);
300		if (!devres)
301			return -ENOMEM;
302
303		devres->polldev = dev;
304	}
305
306	input_set_drvdata(input, dev);
307	INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
308
309	if (!dev->poll_interval)
310		dev->poll_interval = 500;
311	if (!dev->poll_interval_max)
312		dev->poll_interval_max = dev->poll_interval;
313
314	input->open = input_open_polled_device;
315	input->close = input_close_polled_device;
316
317	input->dev.groups = input_polldev_attribute_groups;
318
319	error = input_register_device(input);
320	if (error) {
321		devres_free(devres);
322		return error;
323	}
324
325	/*
326	 * Take extra reference to the underlying input device so
327	 * that it survives call to input_unregister_polled_device()
328	 * and is deleted only after input_free_polled_device()
329	 * has been invoked. This is needed to ease task of freeing
330	 * sparse keymaps.
331	 */
332	input_get_device(input);
333
334	if (dev->devres_managed) {
335		dev_dbg(input->dev.parent, "%s: registering %s with devres.\n",
336			__func__, dev_name(&input->dev));
337		devres_add(input->dev.parent, devres);
338	}
339
340	return 0;
341}
342EXPORT_SYMBOL(input_register_polled_device);
343
344/**
345 * input_unregister_polled_device - unregister polled device
346 * @dev: device to unregister
347 *
348 * The function unregisters previously registered polled input
349 * device from input layer. Polling is stopped and device is
350 * ready to be freed with call to input_free_polled_device().
351 */
352void input_unregister_polled_device(struct input_polled_dev *dev)
353{
354	if (dev->devres_managed)
355		WARN_ON(devres_destroy(dev->input->dev.parent,
356					devm_input_polldev_unregister,
357					devm_input_polldev_match,
358					dev));
359
360	input_unregister_device(dev->input);
361}
362EXPORT_SYMBOL(input_unregister_polled_device);
363