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 int interval;
  88         int err;
  89
  90         err = kstrtouint(buf, 0, &interval);
  91         if (err)
  92                 return err;
  93
  94         if (interval < polldev->poll_interval_min)
  95                 return -EINVAL;
  96
  97         if (interval > polldev->poll_interval_max)
  98                 return -EINVAL;
  99
 100         mutex_lock(&input->mutex);
 101
 102         polldev->poll_interval = interval;
 103
 104         if (input->users) {
 105                 cancel_delayed_work_sync(&polldev->work);
 106                 if (polldev->poll_interval > 0)
 107                         input_polldev_queue_work(polldev);
 108         }
 109
 110         mutex_unlock(&input->mutex);
 111
 112         return count;
 113 }
 114
 115 static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
 116                                             input_polldev_set_poll);
 117
 118
 119 static ssize_t input_polldev_get_max(struct device *dev,
 120                                      struct device_attribute *attr, char *buf)
 121 {
 122         struct input_polled_dev *polldev = dev_get_drvdata(dev);
 123
 124         return sprintf(buf, "%d\n", polldev->poll_interval_max);
 125 }
 126
 127 static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
 128
 129 static ssize_t input_polldev_get_min(struct device *dev,
 130                                      struct device_attribute *attr, char *buf)
 131 {
 132         struct input_polled_dev *polldev = dev_get_drvdata(dev);
 133
 134         return sprintf(buf, "%d\n", polldev->poll_interval_min);
 135 }
 136
 137 static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
 138
 139 static struct attribute *sysfs_attrs[] = {
 140         &dev_attr_poll.attr,
 141         &dev_attr_max.attr,
 142         &dev_attr_min.attr,
 143         NULL
 144 };
 145
 146 static struct attribute_group input_polldev_attribute_group = {
 147         .attrs = sysfs_attrs
 148 };
 149
 150 /**
 151  * input_allocate_polled_device - allocate memory for polled device
 152  *
 153  * The function allocates memory for a polled device and also
 154  * for an input device associated with this polled device.
 155  */
 156 struct input_polled_dev *input_allocate_polled_device(void)
 157 {
 158         struct input_polled_dev *dev;
 159
 160         dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
 161         if (!dev)
 162                 return NULL;
 163
 164         dev->input = input_allocate_device();
 165         if (!dev->input) {
 166                 kfree(dev);
 167                 return NULL;
 168         }
 169
 170         return dev;
 171 }
 172 EXPORT_SYMBOL(input_allocate_polled_device);
 173
 174 /**
 175  * input_free_polled_device - free memory allocated for polled device
 176  * @dev: device to free
 177  *
 178  * The function frees memory allocated for polling device and drops
 179  * reference to the associated input device.
 180  */
 181 void input_free_polled_device(struct input_polled_dev *dev)
 182 {
 183         if (dev) {
 184                 input_free_device(dev->input);
 185                 kfree(dev);
 186         }
 187 }
 188 EXPORT_SYMBOL(input_free_polled_device);
 189
 190 /**
 191  * input_register_polled_device - register polled device
 192  * @dev: device to register
 193  *
 194  * The function registers previously initialized polled input device
 195  * with input layer. The device should be allocated with call to
 196  * input_allocate_polled_device(). Callers should also set up poll()
 197  * method and set up capabilities (id, name, phys, bits) of the
 198  * corresponding input_dev structure.
 199  */
 200 int input_register_polled_device(struct input_polled_dev *dev)
 201 {
 202         struct input_dev *input = dev->input;
 203         int error;
 204
 205         input_set_drvdata(input, dev);
 206         INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
 207         if (!dev->poll_interval)
 208                 dev->poll_interval = 500;
 209         if (!dev->poll_interval_max)
 210                 dev->poll_interval_max = dev->poll_interval;
 211         input->open = input_open_polled_device;
 212         input->close = input_close_polled_device;
 213
 214         error = input_register_device(input);
 215         if (error)
 216                 return error;
 217
 218         error = sysfs_create_group(&input->dev.kobj,
 219                                    &input_polldev_attribute_group);
 220         if (error) {
 221                 input_unregister_device(input);
 222                 return error;
 223         }
 224
 225         /*
 226          * Take extra reference to the underlying input device so
 227          * that it survives call to input_unregister_polled_device()
 228          * and is deleted only after input_free_polled_device()
 229          * has been invoked. This is needed to ease task of freeing
 230          * sparse keymaps.
 231          */
 232         input_get_device(input);
 233
 234         return 0;
 235 }
 236 EXPORT_SYMBOL(input_register_polled_device);
 237
 238 /**
 239  * input_unregister_polled_device - unregister polled device
 240  * @dev: device to unregister
 241  *
 242  * The function unregisters previously registered polled input
 243  * device from input layer. Polling is stopped and device is
 244  * ready to be freed with call to input_free_polled_device().
 245  */
 246 void input_unregister_polled_device(struct input_polled_dev *dev)
 247 {
 248         sysfs_remove_group(&dev->input->dev.kobj,
 249                            &input_polldev_attribute_group);
 250
 251         input_unregister_device(dev->input);
 252 }
 253 EXPORT_SYMBOL(input_unregister_polled_device);