1 // SPDX-License-Identifier: GPL-2.0-only
3 * Support for polling mode for input devices.
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"
15 struct input_dev_poller {
16 void (*poll)(struct input_dev *dev);
18 unsigned int poll_interval; /* msec */
19 unsigned int poll_interval_max; /* msec */
20 unsigned int poll_interval_min; /* msec */
22 struct input_dev *input;
23 struct delayed_work work;
26 static void input_dev_poller_queue_work(struct input_dev_poller *poller)
30 delay = msecs_to_jiffies(poller->poll_interval);
32 delay = round_jiffies_relative(delay);
34 queue_delayed_work(system_freezable_wq, &poller->work, delay);
37 static void input_dev_poller_work(struct work_struct *work)
39 struct input_dev_poller *poller =
40 container_of(work, struct input_dev_poller, work.work);
42 poller->poll(poller->input);
43 input_dev_poller_queue_work(poller);
46 void input_dev_poller_finalize(struct input_dev_poller *poller)
48 if (!poller->poll_interval)
49 poller->poll_interval = 500;
50 if (!poller->poll_interval_max)
51 poller->poll_interval_max = poller->poll_interval;
54 void input_dev_poller_start(struct input_dev_poller *poller)
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);
63 void input_dev_poller_stop(struct input_dev_poller *poller)
65 cancel_delayed_work_sync(&poller->work);
68 int input_setup_polling(struct input_dev *dev,
69 void (*poll_fn)(struct input_dev *dev))
71 struct input_dev_poller *poller;
73 poller = kzalloc(sizeof(*poller), GFP_KERNEL);
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.
80 dev_err(dev->dev.parent ?: &dev->dev,
81 "%s: unable to allocate poller structure\n", __func__);
85 INIT_DELAYED_WORK(&poller->work, input_dev_poller_work);
87 poller->poll = poll_fn;
92 EXPORT_SYMBOL(input_setup_polling);
94 static bool input_dev_ensure_poller(struct input_dev *dev)
97 dev_err(dev->dev.parent ?: &dev->dev,
98 "poller structure has not been set up\n");
105 void input_set_poll_interval(struct input_dev *dev, unsigned int interval)
107 if (input_dev_ensure_poller(dev))
108 dev->poller->poll_interval = interval;
110 EXPORT_SYMBOL(input_set_poll_interval);
112 void input_set_min_poll_interval(struct input_dev *dev, unsigned int interval)
114 if (input_dev_ensure_poller(dev))
115 dev->poller->poll_interval_min = interval;
117 EXPORT_SYMBOL(input_set_min_poll_interval);
119 void input_set_max_poll_interval(struct input_dev *dev, unsigned int interval)
121 if (input_dev_ensure_poller(dev))
122 dev->poller->poll_interval_max = interval;
124 EXPORT_SYMBOL(input_set_max_poll_interval);
126 /* SYSFS interface */
128 static ssize_t input_dev_get_poll_interval(struct device *dev,
129 struct device_attribute *attr,
132 struct input_dev *input = to_input_dev(dev);
134 return sprintf(buf, "%d\n", input->poller->poll_interval);
137 static ssize_t input_dev_set_poll_interval(struct device *dev,
138 struct device_attribute *attr,
139 const char *buf, size_t count)
141 struct input_dev *input = to_input_dev(dev);
142 struct input_dev_poller *poller = input->poller;
143 unsigned int interval;
146 err = kstrtouint(buf, 0, &interval);
150 if (interval < poller->poll_interval_min)
153 if (interval > poller->poll_interval_max)
156 mutex_lock(&input->mutex);
158 poller->poll_interval = interval;
161 cancel_delayed_work_sync(&poller->work);
162 if (poller->poll_interval > 0)
163 input_dev_poller_queue_work(poller);
166 mutex_unlock(&input->mutex);
171 static DEVICE_ATTR(poll, 0644,
172 input_dev_get_poll_interval, input_dev_set_poll_interval);
174 static ssize_t input_dev_get_poll_max(struct device *dev,
175 struct device_attribute *attr, char *buf)
177 struct input_dev *input = to_input_dev(dev);
179 return sprintf(buf, "%d\n", input->poller->poll_interval_max);
182 static DEVICE_ATTR(max, 0444, input_dev_get_poll_max, NULL);
184 static ssize_t input_dev_get_poll_min(struct device *dev,
185 struct device_attribute *attr, char *buf)
187 struct input_dev *input = to_input_dev(dev);
189 return sprintf(buf, "%d\n", input->poller->poll_interval_min);
192 static DEVICE_ATTR(min, 0444, input_dev_get_poll_min, NULL);
194 static umode_t input_poller_attrs_visible(struct kobject *kobj,
195 struct attribute *attr, int n)
197 struct device *dev = kobj_to_dev(kobj);
198 struct input_dev *input = to_input_dev(dev);
200 return input->poller ? attr->mode : 0;
203 static struct attribute *input_poller_attrs[] = {
210 struct attribute_group input_poller_attribute_group = {
211 .is_visible = input_poller_attrs_visible,
212 .attrs = input_poller_attrs,