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 | |
15 | struct 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 | |
26 | static void input_dev_poller_queue_work(struct input_dev_poller *poller) |
27 | { |
28 | unsigned long delay; |
29 | |
30 | delay = msecs_to_jiffies(m: poller->poll_interval); |
31 | if (delay >= HZ) |
32 | delay = round_jiffies_relative(j: delay); |
33 | |
34 | queue_delayed_work(wq: system_freezable_wq, dwork: &poller->work, delay); |
35 | } |
36 | |
37 | static 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 | |
46 | void 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 | |
54 | void 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 | |
63 | void input_dev_poller_stop(struct input_dev_poller *poller) |
64 | { |
65 | cancel_delayed_work_sync(dwork: &poller->work); |
66 | } |
67 | |
68 | int 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(size: 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 | } |
92 | EXPORT_SYMBOL(input_setup_polling); |
93 | |
94 | static 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 | |
105 | void 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 | } |
110 | EXPORT_SYMBOL(input_set_poll_interval); |
111 | |
112 | void 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 | } |
117 | EXPORT_SYMBOL(input_set_min_poll_interval); |
118 | |
119 | void 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 | } |
124 | EXPORT_SYMBOL(input_set_max_poll_interval); |
125 | |
126 | int input_get_poll_interval(struct input_dev *dev) |
127 | { |
128 | if (!dev->poller) |
129 | return -EINVAL; |
130 | |
131 | return dev->poller->poll_interval; |
132 | } |
133 | EXPORT_SYMBOL(input_get_poll_interval); |
134 | |
135 | /* SYSFS interface */ |
136 | |
137 | static 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, fmt: "%d\n" , input->poller->poll_interval); |
144 | } |
145 | |
146 | static 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(s: buf, base: 0, res: &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(dev: input)) { |
170 | cancel_delayed_work_sync(dwork: &poller->work); |
171 | if (poller->poll_interval > 0) |
172 | input_dev_poller_queue_work(poller); |
173 | } |
174 | |
175 | mutex_unlock(lock: &input->mutex); |
176 | |
177 | return count; |
178 | } |
179 | |
180 | static DEVICE_ATTR(poll, 0644, |
181 | input_dev_get_poll_interval, input_dev_set_poll_interval); |
182 | |
183 | static 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, fmt: "%d\n" , input->poller->poll_interval_max); |
189 | } |
190 | |
191 | static DEVICE_ATTR(max, 0444, input_dev_get_poll_max, NULL); |
192 | |
193 | static 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, fmt: "%d\n" , input->poller->poll_interval_min); |
199 | } |
200 | |
201 | static DEVICE_ATTR(min, 0444, input_dev_get_poll_min, NULL); |
202 | |
203 | static 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 | |
212 | static struct attribute *input_poller_attrs[] = { |
213 | &dev_attr_poll.attr, |
214 | &dev_attr_max.attr, |
215 | &dev_attr_min.attr, |
216 | NULL |
217 | }; |
218 | |
219 | struct attribute_group input_poller_attribute_group = { |
220 | .is_visible = input_poller_attrs_visible, |
221 | .attrs = input_poller_attrs, |
222 | }; |
223 | |