summaryrefslogtreecommitdiff
path: root/drivers/input/input-polldev.c
blob: 78df5a74822eb5d875f7928920230204930f1ce0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
/*
 * Generic implementation of a polled input device

 * Copyright (c) 2007 Dmitry Torokhov
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/jiffies.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <linux/module.h>
#include <linux/input-polldev.h>

MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
MODULE_DESCRIPTION("Generic implementation of a polled input device");
MODULE_LICENSE("GPL v2");

static void input_polldev_queue_work(struct input_polled_dev *dev)
{
	unsigned long delay;

	delay = msecs_to_jiffies(dev->poll_interval);
	if (delay >= HZ)
		delay = round_jiffies_relative(delay);

	queue_delayed_work(system_freezable_wq, &dev->work, delay);
}

static void input_polled_device_work(struct work_struct *work)
{
	struct input_polled_dev *dev =
		container_of(work, struct input_polled_dev, work.work);

	dev->poll(dev);
	input_polldev_queue_work(dev);
}

static int input_open_polled_device(struct input_dev *input)
{
	struct input_polled_dev *dev = input_get_drvdata(input);

	if (dev->open)
		dev->open(dev);

	/* Only start polling if polling is enabled */
	if (dev->poll_interval > 0) {
		dev->poll(dev);
		input_polldev_queue_work(dev);
	}

	return 0;
}

static void input_close_polled_device(struct input_dev *input)
{
	struct input_polled_dev *dev = input_get_drvdata(input);

	cancel_delayed_work_sync(&dev->work);

	if (dev->close)
		dev->close(dev);
}

/* SYSFS interface */

static ssize_t input_polldev_get_poll(struct device *dev,
				      struct device_attribute *attr, char *buf)
{
	struct input_polled_dev *polldev = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", polldev->poll_interval);
}

static ssize_t input_polldev_set_poll(struct device *dev,
				struct device_attribute *attr, const char *buf,
				size_t count)
{
	struct input_polled_dev *polldev = dev_get_drvdata(dev);
	struct input_dev *input = polldev->input;
	unsigned int interval;
	int err;

	err = kstrtouint(buf, 0, &interval);
	if (err)
		return err;

	if (interval < polldev->poll_interval_min)
		return -EINVAL;

	if (interval > polldev->poll_interval_max)
		return -EINVAL;

	mutex_lock(&input->mutex);

	polldev->poll_interval = interval;

	if (input->users) {
		cancel_delayed_work_sync(&polldev->work);
		if (polldev->poll_interval > 0)
			input_polldev_queue_work(polldev);
	}

	mutex_unlock(&input->mutex);

	return count;
}

static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
					    input_polldev_set_poll);


static ssize_t input_polldev_get_max(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct input_polled_dev *polldev = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", polldev->poll_interval_max);
}

static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);

static ssize_t input_polldev_get_min(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct input_polled_dev *polldev = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", polldev->poll_interval_min);
}

static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);

static struct attribute *sysfs_attrs[] = {
	&dev_attr_poll.attr,
	&dev_attr_max.attr,
	&dev_attr_min.attr,
	NULL
};

static struct attribute_group input_polldev_attribute_group = {
	.attrs = sysfs_attrs
};

static const struct attribute_group *input_polldev_attribute_groups[] = {
	&input_polldev_attribute_group,
	NULL
};

/**
 * input_allocate_polled_device - allocate memory for polled device
 *
 * The function allocates memory for a polled device and also
 * for an input device associated with this polled device.
 */
struct input_polled_dev *input_allocate_polled_device(void)
{
	struct input_polled_dev *dev;

	dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
	if (!dev)
		return NULL;

	dev->input = input_allocate_device();
	if (!dev->input) {
		kfree(dev);
		return NULL;
	}

	return dev;
}
EXPORT_SYMBOL(input_allocate_polled_device);

struct input_polled_devres {
	struct input_polled_dev *polldev;
};

static int devm_input_polldev_match(struct device *dev, void *res, void *data)
{
	struct input_polled_devres *devres = res;

	return devres->polldev == data;
}

static void devm_input_polldev_release(struct device *dev, void *res)
{
	struct input_polled_devres *devres = res;
	struct input_polled_dev *polldev = devres->polldev;

	dev_dbg(dev, "%s: dropping reference/freeing %s\n",
		__func__, dev_name(&polldev->input->dev));

	input_put_device(polldev->input);
	kfree(polldev);
}

static void devm_input_polldev_unregister(struct device *dev, void *res)
{
	struct input_polled_devres *devres = res;
	struct input_polled_dev *polldev = devres->polldev;

	dev_dbg(dev, "%s: unregistering device %s\n",
		__func__, dev_name(&polldev->input->dev));
	input_unregister_device(polldev->input);

	/*
	 * Note that we are still holding extra reference to the input
	 * device so it will stick around until devm_input_polldev_release()
	 * is called.
	 */
}

/**
 * devm_input_allocate_polled_device - allocate managed polled device
 * @dev: device owning the polled device being created
 *
 * Returns prepared &struct input_polled_dev or %NULL.
 *
 * Managed polled input devices do not need to be explicitly unregistered
 * or freed as it will be done automatically when owner device unbinds
 * from * its driver (or binding fails). Once such managed polled device
 * is allocated, it is ready to be set up and registered in the same
 * fashion as regular polled input devices (using
 * input_register_polled_device() function).
 *
 * If you want to manually unregister and free such managed polled devices,
 * it can be still done by calling input_unregister_polled_device() and
 * input_free_polled_device(), although it is rarely needed.
 *
 * NOTE: the owner device is set up as parent of input device and users
 * should not override it.
 */
struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev)
{
	struct input_polled_dev *polldev;
	struct input_polled_devres *devres;

	devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),
			      GFP_KERNEL);
	if (!devres)
		return NULL;

	polldev = input_allocate_polled_device();
	if (!polldev) {
		devres_free(devres);
		return NULL;
	}

	polldev->input->dev.parent = dev;
	polldev->devres_managed = true;

	devres->polldev = polldev;
	devres_add(dev, devres);

	return polldev;
}
EXPORT_SYMBOL(devm_input_allocate_polled_device);

/**
 * input_free_polled_device - free memory allocated for polled device
 * @dev: device to free
 *
 * The function frees memory allocated for polling device and drops
 * reference to the associated input device.
 */
void input_free_polled_device(struct input_polled_dev *dev)
{
	if (dev) {
		if (dev->devres_managed)
			WARN_ON(devres_destroy(dev->input->dev.parent,
						devm_input_polldev_release,
						devm_input_polldev_match,
						dev));
		input_put_device(dev->input);
		kfree(dev);
	}
}
EXPORT_SYMBOL(input_free_polled_device);

/**
 * input_register_polled_device - register polled device
 * @dev: device to register
 *
 * The function registers previously initialized polled input device
 * with input layer. The device should be allocated with call to
 * input_allocate_polled_device(). Callers should also set up poll()
 * method and set up capabilities (id, name, phys, bits) of the
 * corresponding input_dev structure.
 */
int input_register_polled_device(struct input_polled_dev *dev)
{
	struct input_polled_devres *devres = NULL;
	struct input_dev *input = dev->input;
	int error;

	if (dev->devres_managed) {
		devres = devres_alloc(devm_input_polldev_unregister,
				      sizeof(*devres), GFP_KERNEL);
		if (!devres)
			return -ENOMEM;

		devres->polldev = dev;
	}

	input_set_drvdata(input, dev);
	INIT_DELAYED_WORK(&dev->work, input_polled_device_work);

	if (!dev->poll_interval)
		dev->poll_interval = 500;
	if (!dev->poll_interval_max)
		dev->poll_interval_max = dev->poll_interval;

	input->open = input_open_polled_device;
	input->close = input_close_polled_device;

	input->dev.groups = input_polldev_attribute_groups;

	error = input_register_device(input);
	if (error) {
		devres_free(devres);
		return error;
	}

	/*
	 * Take extra reference to the underlying input device so
	 * that it survives call to input_unregister_polled_device()
	 * and is deleted only after input_free_polled_device()
	 * has been invoked. This is needed to ease task of freeing
	 * sparse keymaps.
	 */
	input_get_device(input);

	if (dev->devres_managed) {
		dev_dbg(input->dev.parent, "%s: registering %s with devres.\n",
			__func__, dev_name(&input->dev));
		devres_add(input->dev.parent, devres);
	}

	return 0;
}
EXPORT_SYMBOL(input_register_polled_device);

/**
 * input_unregister_polled_device - unregister polled device
 * @dev: device to unregister
 *
 * The function unregisters previously registered polled input
 * device from input layer. Polling is stopped and device is
 * ready to be freed with call to input_free_polled_device().
 */
void input_unregister_polled_device(struct input_polled_dev *dev)
{
	if (dev->devres_managed)
		WARN_ON(devres_destroy(dev->input->dev.parent,
					devm_input_polldev_unregister,
					devm_input_polldev_match,
					dev));

	input_unregister_device(dev->input);
}
EXPORT_SYMBOL(input_unregister_polled_device);