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