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