drivers/input/input-polldev.c

   1 /*
   2  * Generic implementation of a polled input device
   3
   4  * Copyright (c) 2007 Dmitry Torokhov
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/jiffies.h>
  14 #include <linux/slab.h>
  15 #include <linux/mutex.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/input-polldev.h>
  18
  19 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
  20 MODULE_DESCRIPTION("Generic implementation of a polled input device");
  21 MODULE_LICENSE("GPL v2");
  22 MODULE_VERSION("0.1");
  23
  24 static void input_polldev_queue_work(struct input_polled_dev *dev)
  25 {
  26         unsigned long delay;
  27
  28         delay = msecs_to_jiffies(dev->poll_interval);
  29         if (delay >= HZ)
  30                 delay = round_jiffies_relative(delay);
  31
  32         queue_delayed_work(system_freezable_wq, &dev->work, delay);
  33 }
  34
  35 static void input_polled_device_work(struct work_struct *work)
  36 {
  37         struct input_polled_dev *dev =
  38                 container_of(work, struct input_polled_dev, work.work);
  39
  40         dev->poll(dev);
  41         input_polldev_queue_work(dev);
  42 }
  43
  44 static int input_open_polled_device(struct input_dev *input)
  45 {
  46         struct input_polled_dev *dev = input_get_drvdata(input);
  47
  48         if (dev->open)
  49                 dev->open(dev);
  50
  51         /* Only start polling if polling is enabled */
  52         if (dev->poll_interval > 0)
  53                 queue_delayed_work(system_freezable_wq, &dev->work, 0);
  54
  55         return 0;
  56 }
  57
  58 static void input_close_polled_device(struct input_dev *input)
  59 {
  60         struct input_polled_dev *dev = input_get_drvdata(input);
  61
  62         cancel_delayed_work_sync(&dev->work);
  63
  64         if (dev->close)
  65                 dev->close(dev);
  66 }
  67
  68 /* SYSFS interface */
  69
  70 static ssize_t input_polldev_get_poll(struct device *dev,
  71                                       struct device_attribute *attr, char *buf)
  72 {
  73         struct input_polled_dev *polldev = dev_get_drvdata(dev);
  74
  75         return sprintf(buf, "%d\n", polldev->poll_interval);
  76 }
  77
  78 static ssize_t input_polldev_set_poll(struct device *dev,
  79                                 struct device_attribute *attr, const char *buf,
  80                                 size_t count)
  81 {
  82         struct input_polled_dev *polldev = dev_get_drvdata(dev);
  83         struct input_dev *input = polldev->input;
  84         unsigned long interval;
  85
  86         if (strict_strtoul(buf, 0, &interval))
  87                 return -EINVAL;
  88
  89         if (interval < polldev->poll_interval_min)
  90                 return -EINVAL;
  91
  92         if (interval > polldev->poll_interval_max)
  93                 return -EINVAL;
  94
  95         mutex_lock(&input->mutex);
  96
  97         polldev->poll_interval = interval;
  98
  99         if (input->users) {
 100                 cancel_delayed_work_sync(&polldev->work);
 101                 if (polldev->poll_interval > 0)
 102                         input_polldev_queue_work(polldev);
 103         }
 104
 105         mutex_unlock(&input->mutex);
 106
 107         return count;
 108 }
 109
 110 static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
 111                                             input_polldev_set_poll);
 112
 113
 114 static ssize_t input_polldev_get_max(struct device *dev,
 115                                      struct device_attribute *attr, char *buf)
 116 {
 117         struct input_polled_dev *polldev = dev_get_drvdata(dev);
 118
 119         return sprintf(buf, "%d\n", polldev->poll_interval_max);
 120 }
 121
 122 static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
 123
 124 static ssize_t input_polldev_get_min(struct device *dev,
 125                                      struct device_attribute *attr, char *buf)
 126 {
 127         struct input_polled_dev *polldev = dev_get_drvdata(dev);
 128
 129         return sprintf(buf, "%d\n", polldev->poll_interval_min);
 130 }
 131
 132 static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
 133
 134 static struct attribute *sysfs_attrs[] = {
 135         &dev_attr_poll.attr,
 136         &dev_attr_max.attr,
 137         &dev_attr_min.attr,
 138         NULL
 139 };
 140
 141 static struct attribute_group input_polldev_attribute_group = {
 142         .attrs = sysfs_attrs
 143 };
 144
 145 /**
 146  * input_allocate_polled_device - allocate memory for polled device
 147  *
 148  * The function allocates memory for a polled device and also
 149  * for an input device associated with this polled device.
 150  */
 151 struct input_polled_dev *input_allocate_polled_device(void)
 152 {
 153         struct input_polled_dev *dev;
 154
 155         dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
 156         if (!dev)
 157                 return NULL;
 158
 159         dev->input = input_allocate_device();
 160         if (!dev->input) {
 161                 kfree(dev);
 162                 return NULL;
 163         }
 164
 165         return dev;
 166 }
 167 EXPORT_SYMBOL(input_allocate_polled_device);
 168
 169 /**
 170  * input_free_polled_device - free memory allocated for polled device
 171  * @dev: device to free
 172  *
 173  * The function frees memory allocated for polling device and drops
 174  * reference to the associated input device.
 175  */
 176 void input_free_polled_device(struct input_polled_dev *dev)
 177 {
 178         if (dev) {
 179                 input_free_device(dev->input);
 180                 kfree(dev);
 181         }
 182 }
 183 EXPORT_SYMBOL(input_free_polled_device);
 184
 185 /**
 186  * input_register_polled_device - register polled device
 187  * @dev: device to register
 188  *
 189  * The function registers previously initialized polled input device
 190  * with input layer. The device should be allocated with call to
 191  * input_allocate_polled_device(). Callers should also set up poll()
 192  * method and set up capabilities (id, name, phys, bits) of the
 193  * corresponding input_dev structure.
 194  */
 195 int input_register_polled_device(struct input_polled_dev *dev)
 196 {
 197         struct input_dev *input = dev->input;
 198         int error;
 199
 200         input_set_drvdata(input, dev);
 201         INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
 202         if (!dev->poll_interval)
 203                 dev->poll_interval = 500;
 204         if (!dev->poll_interval_max)
 205                 dev->poll_interval_max = dev->poll_interval;
 206         input->open = input_open_polled_device;
 207         input->close = input_close_polled_device;
 208
 209         error = input_register_device(input);
 210         if (error)
 211                 return error;
 212
 213         error = sysfs_create_group(&input->dev.kobj,
 214                                    &input_polldev_attribute_group);
 215         if (error) {
 216                 input_unregister_device(input);
 217                 return error;
 218         }
 219
 220         /*
 221          * Take extra reference to the underlying input device so
 222          * that it survives call to input_unregister_polled_device()
 223          * and is deleted only after input_free_polled_device()
 224          * has been invoked. This is needed to ease task of freeing
 225          * sparse keymaps.
 226          */
 227         input_get_device(input);
 228
 229         return 0;
 230 }
 231 EXPORT_SYMBOL(input_register_polled_device);
 232
 233 /**
 234  * input_unregister_polled_device - unregister polled device
 235  * @dev: device to unregister
 236  *
 237  * The function unregisters previously registered polled input
 238  * device from input layer. Polling is stopped and device is
 239  * ready to be freed with call to input_free_polled_device().
 240  */
 241 void input_unregister_polled_device(struct input_polled_dev *dev)
 242 {
 243         sysfs_remove_group(&dev->input->dev.kobj,
 244                            &input_polldev_attribute_group);
 245
 246         input_unregister_device(dev->input);
 247 }
 248 EXPORT_SYMBOL(input_unregister_polled_device);