input-poller.c (5401B)
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};