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 static const struct attribute_group *input_polldev_attribute_groups[] = {
 151         &input_polldev_attribute_group,
 152         NULL
 153 };
 154
 155 /**
 156  * input_allocate_polled_device - allocate memory for polled device
 157  *
 158  * The function allocates memory for a polled device and also
 159  * for an input device associated with this polled device.
 160  */
 161 struct input_polled_dev *input_allocate_polled_device(void)
 162 {
 163         struct input_polled_dev *dev;
 164
 165         dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
 166         if (!dev)
 167                 return NULL;
 168
 169         dev->input = input_allocate_device();
 170         if (!dev->input) {
 171                 kfree(dev);
 172                 return NULL;
 173         }
 174
 175         return dev;
 176 }
 177 EXPORT_SYMBOL(input_allocate_polled_device);
 178
 179 struct input_polled_devres {
 180         struct input_polled_dev *polldev;
 181 };
 182
 183 static int devm_input_polldev_match(struct device *dev, void *res, void *data)
 184 {
 185         struct input_polled_devres *devres = res;
 186
 187         return devres->polldev == data;
 188 }
 189
 190 static void devm_input_polldev_release(struct device *dev, void *res)
 191 {
 192         struct input_polled_devres *devres = res;
 193         struct input_polled_dev *polldev = devres->polldev;
 194
 195         dev_dbg(dev, "%s: dropping reference/freeing %s\n",
 196                 __func__, dev_name(&polldev->input->dev));
 197
 198         input_put_device(polldev->input);
 199         kfree(polldev);
 200 }
 201
 202 static void devm_input_polldev_unregister(struct device *dev, void *res)
 203 {
 204         struct input_polled_devres *devres = res;
 205         struct input_polled_dev *polldev = devres->polldev;
 206
 207         dev_dbg(dev, "%s: unregistering device %s\n",
 208                 __func__, dev_name(&polldev->input->dev));
 209         input_unregister_device(polldev->input);
 210
 211         /*
 212          * Note that we are still holding extra reference to the input
 213          * device so it will stick around until devm_input_polldev_release()
 214          * is called.
 215          */
 216 }
 217
 218 /**
 219  * devm_input_allocate_polled_device - allocate managed polled device
 220  * @dev: device owning the polled device being created
 221  *
 222  * Returns prepared &struct input_polled_dev or %NULL.
 223  *
 224  * Managed polled input devices do not need to be explicitly unregistered
 225  * or freed as it will be done automatically when owner device unbinds
 226  * from * its driver (or binding fails). Once such managed polled device
 227  * is allocated, it is ready to be set up and registered in the same
 228  * fashion as regular polled input devices (using
 229  * input_register_polled_device() function).
 230  *
 231  * If you want to manually unregister and free such managed polled devices,
 232  * it can be still done by calling input_unregister_polled_device() and
 233  * input_free_polled_device(), although it is rarely needed.
 234  *
 235  * NOTE: the owner device is set up as parent of input device and users
 236  * should not override it.
 237  */
 238 struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev)
 239 {
 240         struct input_polled_dev *polldev;
 241         struct input_polled_devres *devres;
 242
 243         devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),
 244                               GFP_KERNEL);
 245         if (!devres)
 246                 return NULL;
 247
 248         polldev = input_allocate_polled_device();
 249         if (!polldev) {
 250                 devres_free(devres);
 251                 return NULL;
 252         }
 253
 254         polldev->input->dev.parent = dev;
 255         polldev->devres_managed = true;
 256
 257         devres->polldev = polldev;
 258         devres_add(dev, devres);
 259
 260         return polldev;
 261 }
 262 EXPORT_SYMBOL(devm_input_allocate_polled_device);
 263
 264 /**
 265  * input_free_polled_device - free memory allocated for polled device
 266  * @dev: device to free
 267  *
 268  * The function frees memory allocated for polling device and drops
 269  * reference to the associated input device.
 270  */
 271 void input_free_polled_device(struct input_polled_dev *dev)
 272 {
 273         if (dev) {
 274                 if (dev->devres_managed)
 275                         WARN_ON(devres_destroy(dev->input->dev.parent,
 276                                                 devm_input_polldev_release,
 277                                                 devm_input_polldev_match,
 278                                                 dev));
 279                 input_put_device(dev->input);
 280                 kfree(dev);
 281         }
 282 }
 283 EXPORT_SYMBOL(input_free_polled_device);
 284
 285 /**
 286  * input_register_polled_device - register polled device
 287  * @dev: device to register
 288  *
 289  * The function registers previously initialized polled input device
 290  * with input layer. The device should be allocated with call to
 291  * input_allocate_polled_device(). Callers should also set up poll()
 292  * method and set up capabilities (id, name, phys, bits) of the
 293  * corresponding input_dev structure.
 294  */
 295 int input_register_polled_device(struct input_polled_dev *dev)
 296 {
 297         struct input_polled_devres *devres = NULL;
 298         struct input_dev *input = dev->input;
 299         int error;
 300
 301         if (dev->devres_managed) {
 302                 devres = devres_alloc(devm_input_polldev_unregister,
 303                                       sizeof(*devres), GFP_KERNEL);
 304                 if (!devres)
 305                         return -ENOMEM;
 306
 307                 devres->polldev = dev;
 308         }
 309
 310         input_set_drvdata(input, dev);
 311         INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
 312
 313         if (!dev->poll_interval)
 314                 dev->poll_interval = 500;
 315         if (!dev->poll_interval_max)
 316                 dev->poll_interval_max = dev->poll_interval;
 317
 318         input->open = input_open_polled_device;
 319         input->close = input_close_polled_device;
 320
 321         input->dev.groups = input_polldev_attribute_groups;
 322
 323         error = input_register_device(input);
 324         if (error) {
 325                 devres_free(devres);
 326                 return error;
 327         }
 328
 329         /*
 330          * Take extra reference to the underlying input device so
 331          * that it survives call to input_unregister_polled_device()
 332          * and is deleted only after input_free_polled_device()
 333          * has been invoked. This is needed to ease task of freeing
 334          * sparse keymaps.
 335          */
 336         input_get_device(input);
 337
 338         if (dev->devres_managed) {
 339                 dev_dbg(input->dev.parent, "%s: registering %s with devres.\n",
 340                         __func__, dev_name(&input->dev));
 341                 devres_add(input->dev.parent, devres);
 342         }
 343
 344         return 0;
 345 }
 346 EXPORT_SYMBOL(input_register_polled_device);
 347
 348 /**
 349  * input_unregister_polled_device - unregister polled device
 350  * @dev: device to unregister
 351  *
 352  * The function unregisters previously registered polled input
 353  * device from input layer. Polling is stopped and device is
 354  * ready to be freed with call to input_free_polled_device().
 355  */
 356 void input_unregister_polled_device(struct input_polled_dev *dev)
 357 {
 358         if (dev->devres_managed)
 359                 WARN_ON(devres_destroy(dev->input->dev.parent,
 360                                         devm_input_polldev_unregister,
 361                                         devm_input_polldev_match,
 362                                         dev));
 363
 364         input_unregister_device(dev->input);
 365 }
 366 EXPORT_SYMBOL(input_unregister_polled_device);