projects/linux·blob v5.13 · refs

222 lines · 5.3 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Support for polling mode for input devices.
4 */
5
6#include <linux/device.h>
7#include <linux/input.h>
8#include <linux/jiffies.h>
9#include <linux/mutex.h>
10#include <linux/slab.h>
11#include <linux/types.h>
12#include <linux/workqueue.h>
13#include "input-poller.h"
14
15struct input_dev_poller {
16 void (*poll)(struct input_dev *dev);
17
18 unsigned int poll_interval; /* msec */
19 unsigned int poll_interval_max; /* msec */
20 unsigned int poll_interval_min; /* msec */
21
22 struct input_dev *input;
23 struct delayed_work work;
24};
25
26static void input_dev_poller_queue_work(struct input_dev_poller *poller)
27{
28 unsigned long delay;
29
30 delay = msecs_to_jiffies(poller->poll_interval);
31 if (delay >= HZ)
32 delay = round_jiffies_relative(delay);
33
34 queue_delayed_work(system_freezable_wq, &poller->work, delay);
35}
36
37static void input_dev_poller_work(struct work_struct *work)
38{
39 struct input_dev_poller *poller =
40 container_of(work, struct input_dev_poller, work.work);
41
42 poller->poll(poller->input);
43 input_dev_poller_queue_work(poller);
44}
45
46void input_dev_poller_finalize(struct input_dev_poller *poller)
47{
48 if (!poller->poll_interval)
49 poller->poll_interval = 500;
50 if (!poller->poll_interval_max)
51 poller->poll_interval_max = poller->poll_interval;
52}
53
54void input_dev_poller_start(struct input_dev_poller *poller)
55{
56 /* Only start polling if polling is enabled */
57 if (poller->poll_interval > 0) {
58 poller->poll(poller->input);
59 input_dev_poller_queue_work(poller);
60 }
61}
62
63void input_dev_poller_stop(struct input_dev_poller *poller)
64{
65 cancel_delayed_work_sync(&poller->work);
66}
67
68int input_setup_polling(struct input_dev *dev,
69 void (*poll_fn)(struct input_dev *dev))
70{
71 struct input_dev_poller *poller;
72
73 poller = kzalloc(sizeof(*poller), GFP_KERNEL);
74 if (!poller) {
75 /*
76 * We want to show message even though kzalloc() may have
77 * printed backtrace as knowing what instance of input
78 * device we were dealing with is helpful.
79 */
80 dev_err(dev->dev.parent ?: &dev->dev,
81 "%s: unable to allocate poller structure\n", __func__);
82 return -ENOMEM;
83 }
84
85 INIT_DELAYED_WORK(&poller->work, input_dev_poller_work);
86 poller->input = dev;
87 poller->poll = poll_fn;
88
89 dev->poller = poller;
90 return 0;
91}
92EXPORT_SYMBOL(input_setup_polling);
93
94static bool input_dev_ensure_poller(struct input_dev *dev)
95{
96 if (!dev->poller) {
97 dev_err(dev->dev.parent ?: &dev->dev,
98 "poller structure has not been set up\n");
99 return false;
100 }
101
102 return true;
103}
104
105void input_set_poll_interval(struct input_dev *dev, unsigned int interval)
106{
107 if (input_dev_ensure_poller(dev))
108 dev->poller->poll_interval = interval;
109}
110EXPORT_SYMBOL(input_set_poll_interval);
111
112void input_set_min_poll_interval(struct input_dev *dev, unsigned int interval)
113{
114 if (input_dev_ensure_poller(dev))
115 dev->poller->poll_interval_min = interval;
116}
117EXPORT_SYMBOL(input_set_min_poll_interval);
118
119void input_set_max_poll_interval(struct input_dev *dev, unsigned int interval)
120{
121 if (input_dev_ensure_poller(dev))
122 dev->poller->poll_interval_max = interval;
123}
124EXPORT_SYMBOL(input_set_max_poll_interval);
125
126int input_get_poll_interval(struct input_dev *dev)
127{
128 if (!dev->poller)
129 return -EINVAL;
130
131 return dev->poller->poll_interval;
132}
133EXPORT_SYMBOL(input_get_poll_interval);
134
135/* SYSFS interface */
136
137static ssize_t input_dev_get_poll_interval(struct device *dev,
138 struct device_attribute *attr,
139 char *buf)
140{
141 struct input_dev *input = to_input_dev(dev);
142
143 return sprintf(buf, "%d\n", input->poller->poll_interval);
144}
145
146static ssize_t input_dev_set_poll_interval(struct device *dev,
147 struct device_attribute *attr,
148 const char *buf, size_t count)
149{
150 struct input_dev *input = to_input_dev(dev);
151 struct input_dev_poller *poller = input->poller;
152 unsigned int interval;
153 int err;
154
155 err = kstrtouint(buf, 0, &interval);
156 if (err)
157 return err;
158
159 if (interval < poller->poll_interval_min)
160 return -EINVAL;
161
162 if (interval > poller->poll_interval_max)
163 return -EINVAL;
164
165 mutex_lock(&input->mutex);
166
167 poller->poll_interval = interval;
168
169 if (input_device_enabled(input)) {
170 cancel_delayed_work_sync(&poller->work);
171 if (poller->poll_interval > 0)
172 input_dev_poller_queue_work(poller);
173 }
174
175 mutex_unlock(&input->mutex);
176
177 return count;
178}
179
180static DEVICE_ATTR(poll, 0644,
181 input_dev_get_poll_interval, input_dev_set_poll_interval);
182
183static ssize_t input_dev_get_poll_max(struct device *dev,
184 struct device_attribute *attr, char *buf)
185{
186 struct input_dev *input = to_input_dev(dev);
187
188 return sprintf(buf, "%d\n", input->poller->poll_interval_max);
189}
190
191static DEVICE_ATTR(max, 0444, input_dev_get_poll_max, NULL);
192
193static ssize_t input_dev_get_poll_min(struct device *dev,
194 struct device_attribute *attr, char *buf)
195{
196 struct input_dev *input = to_input_dev(dev);
197
198 return sprintf(buf, "%d\n", input->poller->poll_interval_min);
199}
200
201static DEVICE_ATTR(min, 0444, input_dev_get_poll_min, NULL);
202
203static umode_t input_poller_attrs_visible(struct kobject *kobj,
204 struct attribute *attr, int n)
205{
206 struct device *dev = kobj_to_dev(kobj);
207 struct input_dev *input = to_input_dev(dev);
208
209 return input->poller ? attr->mode : 0;
210}
211
212static struct attribute *input_poller_attrs[] = {
213 &dev_attr_poll.attr,
214 &dev_attr_max.attr,
215 &dev_attr_min.attr,
216 NULL
217};
218
219struct attribute_group input_poller_attribute_group = {
220 .is_visible = input_poller_attrs_visible,
221 .attrs = input_poller_attrs,
222};