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