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

source code of linux/drivers/input/input-poller.c

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