drivers/input/input-polldev.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Generic implementation of a polled input device
   4
   5  * Copyright (c) 2007 Dmitry Torokhov
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/jiffies.h>
  11 #include <linux/slab.h>
  12 #include <linux/mutex.h>
  13 #include <linux/workqueue.h>
  14 #include <linux/module.h>
  15 #include <linux/input-polldev.h>
  16
  17 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
  18 MODULE_DESCRIPTION("Generic implementation of a polled input device");
  19 MODULE_LICENSE("GPL v2");
  20
  21 static void input_polldev_queue_work(struct input_polled_dev *dev)
  22 {
  23         unsigned long delay;
  24
  25         delay = msecs_to_jiffies(dev->poll_interval);
  26         if (delay >= HZ)
  27                 delay = round_jiffies_relative(delay);
  28
  29         queue_delayed_work(system_freezable_wq, &dev->work, delay);
  30 }
  31
  32 static void input_polled_device_work(struct work_struct *work)
  33 {
  34         struct input_polled_dev *dev =
  35                 container_of(work, struct input_polled_dev, work.work);
  36
  37         dev->poll(dev);
  38         input_polldev_queue_work(dev);
  39 }
  40
  41 static int input_open_polled_device(struct input_dev *input)
  42 {
  43         struct input_polled_dev *dev = input_get_drvdata(input);
  44
  45         if (dev->open)
  46                 dev->open(dev);
  47
  48         /* Only start polling if polling is enabled */
  49         if (dev->poll_interval > 0) {
  50                 dev->poll(dev);
  51                 input_polldev_queue_work(dev);
  52         }
  53
  54         return 0;
  55 }
  56
  57 static void input_close_polled_device(struct input_dev *input)
  58 {
  59         struct input_polled_dev *dev = input_get_drvdata(input);
  60
  61         cancel_delayed_work_sync(&dev->work);
  62
  63         if (dev->close)
  64                 dev->close(dev);
  65 }
  66
  67 /* SYSFS interface */
  68
  69 static ssize_t input_polldev_get_poll(struct device *dev,
  70                                       struct device_attribute *attr, char *buf)
  71 {
  72         struct input_polled_dev *polldev = dev_get_drvdata(dev);
  73
  74         return sprintf(buf, "%d\n", polldev->poll_interval);
  75 }
  76
  77 static ssize_t input_polldev_set_poll(struct device *dev,
  78                                 struct device_attribute *attr, const char *buf,
  79                                 size_t count)
  80 {
  81         struct input_polled_dev *polldev = dev_get_drvdata(dev);
  82         struct input_dev *input = polldev->input;
  83         unsigned int interval;
  84         int err;
  85
  86         err = kstrtouint(buf, 0, &interval);
  87         if (err)
  88                 return err;
  89
  90         if (interval < polldev->poll_interval_min)
  91                 return -EINVAL;
  92
  93         if (interval > polldev->poll_interval_max)
  94                 return -EINVAL;
  95
  96         mutex_lock(&input->mutex);
  97
  98         polldev->poll_interval = interval;
  99
 100         if (input->users) {
 101                 cancel_delayed_work_sync(&polldev->work);
 102                 if (polldev->poll_interval > 0)
 103                         input_polldev_queue_work(polldev);
 104         }
 105
 106         mutex_unlock(&input->mutex);
 107
 108         return count;
 109 }
 110
 111 static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
 112                                             input_polldev_set_poll);
 113
 114
 115 static ssize_t input_polldev_get_max(struct device *dev,
 116                                      struct device_attribute *attr, char *buf)
 117 {
 118         struct input_polled_dev *polldev = dev_get_drvdata(dev);
 119
 120         return sprintf(buf, "%d\n", polldev->poll_interval_max);
 121 }
 122
 123 static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
 124
 125 static ssize_t input_polldev_get_min(struct device *dev,
 126                                      struct device_attribute *attr, char *buf)
 127 {
 128         struct input_polled_dev *polldev = dev_get_drvdata(dev);
 129
 130         return sprintf(buf, "%d\n", polldev->poll_interval_min);
 131 }
 132
 133 static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
 134
 135 static struct attribute *sysfs_attrs[] = {
 136         &dev_attr_poll.attr,
 137         &dev_attr_max.attr,
 138         &dev_attr_min.attr,
 139         NULL
 140 };
 141
 142 static struct attribute_group input_polldev_attribute_group = {
 143         .attrs = sysfs_attrs
 144 };
 145
 146 static const struct attribute_group *input_polldev_attribute_groups[] = {
 147         &input_polldev_attribute_group,
 148         NULL
 149 };
 150
 151 /**
 152  * input_allocate_polled_device - allocate memory for polled device
 153  *
 154  * The function allocates memory for a polled device and also
 155  * for an input device associated with this polled device.
 156  */
 157 struct input_polled_dev *input_allocate_polled_device(void)
 158 {
 159         struct input_polled_dev *dev;
 160
 161         dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
 162         if (!dev)
 163                 return NULL;
 164
 165         dev->input = input_allocate_device();
 166         if (!dev->input) {
 167                 kfree(dev);
 168                 return NULL;
 169         }
 170
 171         return dev;
 172 }
 173 EXPORT_SYMBOL(input_allocate_polled_device);
 174
 175 struct input_polled_devres {
 176         struct input_polled_dev *polldev;
 177 };
 178
 179 static int devm_input_polldev_match(struct device *dev, void *res, void *data)
 180 {
 181         struct input_polled_devres *devres = res;
 182
 183         return devres->polldev == data;
 184 }
 185
 186 static void devm_input_polldev_release(struct device *dev, void *res)
 187 {
 188         struct input_polled_devres *devres = res;
 189         struct input_polled_dev *polldev = devres->polldev;
 190
 191         dev_dbg(dev, "%s: dropping reference/freeing %s\n",
 192                 __func__, dev_name(&polldev->input->dev));
 193
 194         input_put_device(polldev->input);
 195         kfree(polldev);
 196 }
 197
 198 static void devm_input_polldev_unregister(struct device *dev, void *res)
 199 {
 200         struct input_polled_devres *devres = res;
 201         struct input_polled_dev *polldev = devres->polldev;
 202
 203         dev_dbg(dev, "%s: unregistering device %s\n",
 204                 __func__, dev_name(&polldev->input->dev));
 205         input_unregister_device(polldev->input);
 206
 207         /*
 208          * Note that we are still holding extra reference to the input
 209          * device so it will stick around until devm_input_polldev_release()
 210          * is called.
 211          */
 212 }
 213
 214 /**
 215  * devm_input_allocate_polled_device - allocate managed polled device
 216  * @dev: device owning the polled device being created
 217  *
 218  * Returns prepared &struct input_polled_dev or %NULL.
 219  *
 220  * Managed polled input devices do not need to be explicitly unregistered
 221  * or freed as it will be done automatically when owner device unbinds
 222  * from * its driver (or binding fails). Once such managed polled device
 223  * is allocated, it is ready to be set up and registered in the same
 224  * fashion as regular polled input devices (using
 225  * input_register_polled_device() function).
 226  *
 227  * If you want to manually unregister and free such managed polled devices,
 228  * it can be still done by calling input_unregister_polled_device() and
 229  * input_free_polled_device(), although it is rarely needed.
 230  *
 231  * NOTE: the owner device is set up as parent of input device and users
 232  * should not override it.
 233  */
 234 struct input_polled_dev *devm_input_allocate_polled_device(struct device *dev)
 235 {
 236         struct input_polled_dev *polldev;
 237         struct input_polled_devres *devres;
 238
 239         devres = devres_alloc(devm_input_polldev_release, sizeof(*devres),
 240                               GFP_KERNEL);
 241         if (!devres)
 242                 return NULL;
 243
 244         polldev = input_allocate_polled_device();
 245         if (!polldev) {
 246                 devres_free(devres);
 247                 return NULL;
 248         }
 249
 250         polldev->input->dev.parent = dev;
 251         polldev->devres_managed = true;
 252
 253         devres->polldev = polldev;
 254         devres_add(dev, devres);
 255
 256         return polldev;
 257 }
 258 EXPORT_SYMBOL(devm_input_allocate_polled_device);
 259
 260 /**
 261  * input_free_polled_device - free memory allocated for polled device
 262  * @dev: device to free
 263  *
 264  * The function frees memory allocated for polling device and drops
 265  * reference to the associated input device.
 266  */
 267 void input_free_polled_device(struct input_polled_dev *dev)
 268 {
 269         if (dev) {
 270                 if (dev->devres_managed)
 271                         WARN_ON(devres_destroy(dev->input->dev.parent,
 272                                                 devm_input_polldev_release,
 273                                                 devm_input_polldev_match,
 274                                                 dev));
 275                 input_put_device(dev->input);
 276                 kfree(dev);
 277         }
 278 }
 279 EXPORT_SYMBOL(input_free_polled_device);
 280
 281 /**
 282  * input_register_polled_device - register polled device
 283  * @dev: device to register
 284  *
 285  * The function registers previously initialized polled input device
 286  * with input layer. The device should be allocated with call to
 287  * input_allocate_polled_device(). Callers should also set up poll()
 288  * method and set up capabilities (id, name, phys, bits) of the
 289  * corresponding input_dev structure.
 290  */
 291 int input_register_polled_device(struct input_polled_dev *dev)
 292 {
 293         struct input_polled_devres *devres = NULL;
 294         struct input_dev *input = dev->input;
 295         int error;
 296
 297         if (dev->devres_managed) {
 298                 devres = devres_alloc(devm_input_polldev_unregister,
 299                                       sizeof(*devres), GFP_KERNEL);
 300                 if (!devres)
 301                         return -ENOMEM;
 302
 303                 devres->polldev = dev;
 304         }
 305
 306         input_set_drvdata(input, dev);
 307         INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
 308
 309         if (!dev->poll_interval)
 310                 dev->poll_interval = 500;
 311         if (!dev->poll_interval_max)
 312                 dev->poll_interval_max = dev->poll_interval;
 313
 314         input->open = input_open_polled_device;
 315         input->close = input_close_polled_device;
 316
 317         input->dev.groups = input_polldev_attribute_groups;
 318
 319         error = input_register_device(input);
 320         if (error) {
 321                 devres_free(devres);
 322                 return error;
 323         }
 324
 325         /*
 326          * Take extra reference to the underlying input device so
 327          * that it survives call to input_unregister_polled_device()
 328          * and is deleted only after input_free_polled_device()
 329          * has been invoked. This is needed to ease task of freeing
 330          * sparse keymaps.
 331          */
 332         input_get_device(input);
 333
 334         if (dev->devres_managed) {
 335                 dev_dbg(input->dev.parent, "%s: registering %s with devres.\n",
 336                         __func__, dev_name(&input->dev));
 337                 devres_add(input->dev.parent, devres);
 338         }
 339
 340         return 0;
 341 }
 342 EXPORT_SYMBOL(input_register_polled_device);
 343
 344 /**
 345  * input_unregister_polled_device - unregister polled device
 346  * @dev: device to unregister
 347  *
 348  * The function unregisters previously registered polled input
 349  * device from input layer. Polling is stopped and device is
 350  * ready to be freed with call to input_free_polled_device().
 351  */
 352 void input_unregister_polled_device(struct input_polled_dev *dev)
 353 {
 354         if (dev->devres_managed)
 355                 WARN_ON(devres_destroy(dev->input->dev.parent,
 356                                         devm_input_polldev_unregister,
 357                                         devm_input_polldev_match,
 358                                         dev));
 359
 360         input_unregister_device(dev->input);
 361 }
 362 EXPORT_SYMBOL(input_unregister_polled_device);