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
  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 int interval;
  87         int err;
  88
  89         err = kstrtouint(buf, 0, &interval);
  90         if (err)
  91                 return err;
  92
  93         if (interval < polldev->poll_interval_min)
  94                 return -EINVAL;
  95
  96         if (interval > polldev->poll_interval_max)
  97                 return -EINVAL;
  98
  99         mutex_lock(&input->mutex);
 100
 101         polldev->poll_interval = interval;
 102
 103         if (input->users) {
 104                 cancel_delayed_work_sync(&polldev->work);
 105                 if (polldev->poll_interval > 0)
 106                         input_polldev_queue_work(polldev);
 107         }
 108
 109         mutex_unlock(&input->mutex);
 110
 111         return count;
 112 }
 113
 114 static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
 115                                             input_polldev_set_poll);
 116
 117
 118 static ssize_t input_polldev_get_max(struct device *dev,
 119                                      struct device_attribute *attr, char *buf)
 120 {
 121         struct input_polled_dev *polldev = dev_get_drvdata(dev);
 122
 123         return sprintf(buf, "%d\n", polldev->poll_interval_max);
 124 }
 125
 126 static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
 127
 128 static ssize_t input_polldev_get_min(struct device *dev,
 129                                      struct device_attribute *attr, char *buf)
 130 {
 131         struct input_polled_dev *polldev = dev_get_drvdata(dev);
 132
 133         return sprintf(buf, "%d\n", polldev->poll_interval_min);
 134 }
 135
 136 static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
 137
 138 static struct attribute *sysfs_attrs[] = {
 139         &dev_attr_poll.attr,
 140         &dev_attr_max.attr,
 141         &dev_attr_min.attr,
 142         NULL
 143 };
 144
 145 static struct attribute_group input_polldev_attribute_group = {
 146         .attrs = sysfs_attrs
 147 };
 148
 149 static const struct attribute_group *input_polldev_attribute_groups[] = {
 150         &input_polldev_attribute_group,
 151         NULL
 152 };
 153
 154 /**
 155  * input_allocate_polled_device - allocate memory for polled device
 156  *
 157  * The function allocates memory for a polled device and also
 158  * for an input device associated with this polled device.
 159  */
 160 struct input_polled_dev *input_allocate_polled_device(void)
 161 {
 162         struct input_polled_dev *dev;
 163
 164         dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
 165         if (!dev)
 166                 return NULL;
 167
 168         dev->input = input_allocate_device();
 169         if (!dev->input) {
 170                 kfree(dev);
 171                 return NULL;
 172         }
 173
 174         return dev;
 175 }
 176 EXPORT_SYMBOL(input_allocate_polled_device);
 177
 178 struct input_polled_devres {
 179         struct input_polled_dev *polldev;
 180 };
 181
 182 static int devm_input_polldev_match(struct device *dev, void *res, void *data)
 183 {
 184         struct input_polled_devres *devres = res;
 185
 186         return devres->polldev == data;
 187 }
 188
 189 static void devm_input_polldev_release(struct device *dev, void *res)
 190 {
 191         struct input_polled_devres *devres = res;
 192         struct input_polled_dev *polldev = devres->polldev;
 193
 194         dev_dbg(dev, "%s: dropping reference/freeing %s\n",
 195                 __func__, dev_name(&polldev->input->dev));
 196
 197         input_put_device(polldev->input);
 198         kfree(polldev);
 199 }
 200
 201 static void devm_input_polldev_unregister(struct device *dev, void *res)
 202 {
 203         struct input_polled_devres *devres = res;
 204         struct input_polled_dev *polldev = devres->polldev;
 205
 206         dev_dbg(dev, "%s: unregistering device %s\n",
 207                 __func__, dev_name(&polldev->input->dev));
 208         input_unregister_device(polldev->input);
 209
 210         /*
 211          * Note that we are still holding extra reference to the input
 212          * device so it will stick around until devm_input_polldev_release()
 213          * is called.
 214          */
 215 }
 216
 217 /**
 218  * devm_input_allocate_polled_device - allocate managed polled device
 219  * @dev: device owning the polled device being created
 220  *
 221  * Returns prepared &struct input_polled_dev or %NULL.
 222  *
 223  * Managed polled input devices do not need to be explicitly unregistered
 224  * or freed as it will be done automatically when owner device unbinds
 225  * from * its driver (or binding fails). Once such managed polled device
 226  * is allocated, it is ready to be set up and registered in the same
 227  * fashion as regular polled input devices (using
 228  * input_register_polled_device() function).
 229  *
 230  * If you want to manually unregister and free such managed polled devices,
 231  * it can be still done by calling input_unregister_polled_device() and
 232  * input_free_polled_device(), although it is rarely needed.
 233  *
 234  * NOTE: the owner device is set up as parent of input device and users
 235  * should not override it.
 236  */
 237 struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev)
 238 {
 239         struct input_polled_dev *polldev;
 240         struct input_polled_devres *devres;
 241
 242         devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),
 243                               GFP_KERNEL);
 244         if (!devres)
 245                 return NULL;
 246
 247         polldev = input_allocate_polled_device();
 248         if (!polldev) {
 249                 devres_free(devres);
 250                 return NULL;
 251         }
 252
 253         polldev->input->dev.parent = dev;
 254         polldev->devres_managed = true;
 255
 256         devres->polldev = polldev;
 257         devres_add(dev, devres);
 258
 259         return polldev;
 260 }
 261 EXPORT_SYMBOL(devm_input_allocate_polled_device);
 262
 263 /**
 264  * input_free_polled_device - free memory allocated for polled device
 265  * @dev: device to free
 266  *
 267  * The function frees memory allocated for polling device and drops
 268  * reference to the associated input device.
 269  */
 270 void input_free_polled_device(struct input_polled_dev *dev)
 271 {
 272         if (dev) {
 273                 if (dev->devres_managed)
 274                         WARN_ON(devres_destroy(dev->input->dev.parent,
 275                                                 devm_input_polldev_release,
 276                                                 devm_input_polldev_match,
 277                                                 dev));
 278                 input_put_device(dev->input);
 279                 kfree(dev);
 280         }
 281 }
 282 EXPORT_SYMBOL(input_free_polled_device);
 283
 284 /**
 285  * input_register_polled_device - register polled device
 286  * @dev: device to register
 287  *
 288  * The function registers previously initialized polled input device
 289  * with input layer. The device should be allocated with call to
 290  * input_allocate_polled_device(). Callers should also set up poll()
 291  * method and set up capabilities (id, name, phys, bits) of the
 292  * corresponding input_dev structure.
 293  */
 294 int input_register_polled_device(struct input_polled_dev *dev)
 295 {
 296         struct input_polled_devres *devres = NULL;
 297         struct input_dev *input = dev->input;
 298         int error;
 299
 300         if (dev->devres_managed) {
 301                 devres = devres_alloc(devm_input_polldev_unregister,
 302                                       sizeof(*devres), GFP_KERNEL);
 303                 if (!devres)
 304                         return -ENOMEM;
 305
 306                 devres->polldev = dev;
 307         }
 308
 309         input_set_drvdata(input, dev);
 310         INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
 311
 312         if (!dev->poll_interval)
 313                 dev->poll_interval = 500;
 314         if (!dev->poll_interval_max)
 315                 dev->poll_interval_max = dev->poll_interval;
 316
 317         input->open = input_open_polled_device;
 318         input->close = input_close_polled_device;
 319
 320         input->dev.groups = input_polldev_attribute_groups;
 321
 322         error = input_register_device(input);
 323         if (error) {
 324                 devres_free(devres);
 325                 return error;
 326         }
 327
 328         /*
 329          * Take extra reference to the underlying input device so
 330          * that it survives call to input_unregister_polled_device()
 331          * and is deleted only after input_free_polled_device()
 332          * has been invoked. This is needed to ease task of freeing
 333          * sparse keymaps.
 334          */
 335         input_get_device(input);
 336
 337         if (dev->devres_managed) {
 338                 dev_dbg(input->dev.parent, "%s: registering %s with devres.\n",
 339                         __func__, dev_name(&input->dev));
 340                 devres_add(input->dev.parent, devres);
 341         }
 342
 343         return 0;
 344 }
 345 EXPORT_SYMBOL(input_register_polled_device);
 346
 347 /**
 348  * input_unregister_polled_device - unregister polled device
 349  * @dev: device to unregister
 350  *
 351  * The function unregisters previously registered polled input
 352  * device from input layer. Polling is stopped and device is
 353  * ready to be freed with call to input_free_polled_device().
 354  */
 355 void input_unregister_polled_device(struct input_polled_dev *dev)
 356 {
 357         if (dev->devres_managed)
 358                 WARN_ON(devres_destroy(dev->input->dev.parent,
 359                                         devm_input_polldev_unregister,
 360                                         devm_input_polldev_match,
 361                                         dev));
 362
 363         input_unregister_device(dev->input);
 364 }
 365 EXPORT_SYMBOL(input_unregister_polled_device);