drivers/devfreq/devfreq-event.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * devfreq-event: a framework to provide raw data and events of devfreq devices
   4  *
   5  * Copyright (C) 2015 Samsung Electronics
   6  * Author: Chanwoo Choi <cw00.choi@samsung.com>
   7  *
   8  * This driver is based on drivers/devfreq/devfreq.c.
   9  */
  10
  11 #include <linux/devfreq-event.h>
  12 #include <linux/kernel.h>
  13 #include <linux/err.h>
  14 #include <linux/init.h>
  15 #include <linux/export.h>
  16 #include <linux/slab.h>
  17 #include <linux/list.h>
  18 #include <linux/of.h>
  19
  20 static struct class *devfreq_event_class;
  21
  22 /* The list of all devfreq event list */
  23 static LIST_HEAD(devfreq_event_list);
  24 static DEFINE_MUTEX(devfreq_event_list_lock);
  25
  26 #define to_devfreq_event(DEV) container_of(DEV, struct devfreq_event_dev, dev)
  27
  28 /**
  29  * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
  30  *                               the enable_count of devfreq-event dev.
  31  * @edev        : the devfreq-event device
  32  *
  33  * Note that this function increase the enable_count and enable the
  34  * devfreq-event device. The devfreq-event device should be enabled before
  35  * using it by devfreq device.
  36  */
  37 int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
  38 {
  39         int ret = 0;
  40
  41         if (!edev || !edev->desc)
  42                 return -EINVAL;
  43
  44         mutex_lock(&edev->lock);
  45         if (edev->desc->ops && edev->desc->ops->enable
  46                         && edev->enable_count == 0) {
  47                 ret = edev->desc->ops->enable(edev);
  48                 if (ret < 0)
  49                         goto err;
  50         }
  51         edev->enable_count++;
  52 err:
  53         mutex_unlock(&edev->lock);
  54
  55         return ret;
  56 }
  57 EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
  58
  59 /**
  60  * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
  61  *                                the enable_count of the devfreq-event dev.
  62  * @edev        : the devfreq-event device
  63  *
  64  * Note that this function decrease the enable_count and disable the
  65  * devfreq-event device. After the devfreq-event device is disabled,
  66  * devfreq device can't use the devfreq-event device for get/set/reset
  67  * operations.
  68  */
  69 int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
  70 {
  71         int ret = 0;
  72
  73         if (!edev || !edev->desc)
  74                 return -EINVAL;
  75
  76         mutex_lock(&edev->lock);
  77         if (edev->enable_count <= 0) {
  78                 dev_warn(&edev->dev, "unbalanced enable_count\n");
  79                 ret = -EIO;
  80                 goto err;
  81         }
  82
  83         if (edev->desc->ops && edev->desc->ops->disable
  84                         && edev->enable_count == 1) {
  85                 ret = edev->desc->ops->disable(edev);
  86                 if (ret < 0)
  87                         goto err;
  88         }
  89         edev->enable_count--;
  90 err:
  91         mutex_unlock(&edev->lock);
  92
  93         return ret;
  94 }
  95 EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
  96
  97 /**
  98  * devfreq_event_is_enabled() - Check whether devfreq-event dev is enabled or
  99  *                              not.
 100  * @edev        : the devfreq-event device
 101  *
 102  * Note that this function check whether devfreq-event dev is enabled or not.
 103  * If return true, the devfreq-event dev is enabeld. If return false, the
 104  * devfreq-event dev is disabled.
 105  */
 106 bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
 107 {
 108         bool enabled = false;
 109
 110         if (!edev || !edev->desc)
 111                 return enabled;
 112
 113         mutex_lock(&edev->lock);
 114
 115         if (edev->enable_count > 0)
 116                 enabled = true;
 117
 118         mutex_unlock(&edev->lock);
 119
 120         return enabled;
 121 }
 122 EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
 123
 124 /**
 125  * devfreq_event_set_event() - Set event to devfreq-event dev to start.
 126  * @edev        : the devfreq-event device
 127  *
 128  * Note that this function set the event to the devfreq-event device to start
 129  * for getting the event data which could be various event type.
 130  */
 131 int devfreq_event_set_event(struct devfreq_event_dev *edev)
 132 {
 133         int ret;
 134
 135         if (!edev || !edev->desc)
 136                 return -EINVAL;
 137
 138         if (!edev->desc->ops || !edev->desc->ops->set_event)
 139                 return -EINVAL;
 140
 141         if (!devfreq_event_is_enabled(edev))
 142                 return -EPERM;
 143
 144         mutex_lock(&edev->lock);
 145         ret = edev->desc->ops->set_event(edev);
 146         mutex_unlock(&edev->lock);
 147
 148         return ret;
 149 }
 150 EXPORT_SYMBOL_GPL(devfreq_event_set_event);
 151
 152 /**
 153  * devfreq_event_get_event() - Get {load|total}_count from devfreq-event dev.
 154  * @edev        : the devfreq-event device
 155  * @edata       : the calculated data of devfreq-event device
 156  *
 157  * Note that this function get the calculated event data from devfreq-event dev
 158  * after stoping the progress of whole sequence of devfreq-event dev.
 159  */
 160 int devfreq_event_get_event(struct devfreq_event_dev *edev,
 161                             struct devfreq_event_data *edata)
 162 {
 163         int ret;
 164
 165         if (!edev || !edev->desc)
 166                 return -EINVAL;
 167
 168         if (!edev->desc->ops || !edev->desc->ops->get_event)
 169                 return -EINVAL;
 170
 171         if (!devfreq_event_is_enabled(edev))
 172                 return -EINVAL;
 173
 174         edata->total_count = edata->load_count = 0;
 175
 176         mutex_lock(&edev->lock);
 177         ret = edev->desc->ops->get_event(edev, edata);
 178         if (ret < 0)
 179                 edata->total_count = edata->load_count = 0;
 180         mutex_unlock(&edev->lock);
 181
 182         return ret;
 183 }
 184 EXPORT_SYMBOL_GPL(devfreq_event_get_event);
 185
 186 /**
 187  * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
 188  * @edev        : the devfreq-event device
 189  *
 190  * Note that this function stop all operations of devfreq-event dev and reset
 191  * the current event data to make the devfreq-event device into initial state.
 192  */
 193 int devfreq_event_reset_event(struct devfreq_event_dev *edev)
 194 {
 195         int ret = 0;
 196
 197         if (!edev || !edev->desc)
 198                 return -EINVAL;
 199
 200         if (!devfreq_event_is_enabled(edev))
 201                 return -EPERM;
 202
 203         mutex_lock(&edev->lock);
 204         if (edev->desc->ops && edev->desc->ops->reset)
 205                 ret = edev->desc->ops->reset(edev);
 206         mutex_unlock(&edev->lock);
 207
 208         return ret;
 209 }
 210 EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
 211
 212 /**
 213  * devfreq_event_get_edev_by_phandle() - Get the devfreq-event dev from
 214  *                                       devicetree.
 215  * @dev         : the pointer to the given device
 216  * @index       : the index into list of devfreq-event device
 217  *
 218  * Note that this function return the pointer of devfreq-event device.
 219  */
 220 struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
 221                                                       int index)
 222 {
 223         struct device_node *node;
 224         struct devfreq_event_dev *edev;
 225
 226         if (!dev->of_node)
 227                 return ERR_PTR(-EINVAL);
 228
 229         node = of_parse_phandle(dev->of_node, "devfreq-events", index);
 230         if (!node)
 231                 return ERR_PTR(-ENODEV);
 232
 233         mutex_lock(&devfreq_event_list_lock);
 234         list_for_each_entry(edev, &devfreq_event_list, node) {
 235                 if (edev->dev.parent && edev->dev.parent->of_node == node)
 236                         goto out;
 237         }
 238
 239         list_for_each_entry(edev, &devfreq_event_list, node) {
 240                 if (of_node_name_eq(node, edev->desc->name))
 241                         goto out;
 242         }
 243         edev = NULL;
 244 out:
 245         mutex_unlock(&devfreq_event_list_lock);
 246
 247         if (!edev) {
 248                 of_node_put(node);
 249                 return ERR_PTR(-ENODEV);
 250         }
 251
 252         of_node_put(node);
 253
 254         return edev;
 255 }
 256 EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
 257
 258 /**
 259  * devfreq_event_get_edev_count() - Get the count of devfreq-event dev
 260  * @dev         : the pointer to the given device
 261  *
 262  * Note that this function return the count of devfreq-event devices.
 263  */
 264 int devfreq_event_get_edev_count(struct device *dev)
 265 {
 266         int count;
 267
 268         if (!dev->of_node) {
 269                 dev_err(dev, "device does not have a device node entry\n");
 270                 return -EINVAL;
 271         }
 272
 273         count = of_property_count_elems_of_size(dev->of_node, "devfreq-events",
 274                                                 sizeof(u32));
 275         if (count < 0) {
 276                 dev_err(dev,
 277                         "failed to get the count of devfreq-event in %pOF node\n",
 278                         dev->of_node);
 279                 return count;
 280         }
 281
 282         return count;
 283 }
 284 EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
 285
 286 static void devfreq_event_release_edev(struct device *dev)
 287 {
 288         struct devfreq_event_dev *edev = to_devfreq_event(dev);
 289
 290         kfree(edev);
 291 }
 292
 293 /**
 294  * devfreq_event_add_edev() - Add new devfreq-event device.
 295  * @dev         : the device owning the devfreq-event device being created
 296  * @desc        : the devfreq-event device's decriptor which include essential
 297  *                data for devfreq-event device.
 298  *
 299  * Note that this function add new devfreq-event device to devfreq-event class
 300  * list and register the device of the devfreq-event device.
 301  */
 302 struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
 303                                                 struct devfreq_event_desc *desc)
 304 {
 305         struct devfreq_event_dev *edev;
 306         static atomic_t event_no = ATOMIC_INIT(-1);
 307         int ret;
 308
 309         if (!dev || !desc)
 310                 return ERR_PTR(-EINVAL);
 311
 312         if (!desc->name || !desc->ops)
 313                 return ERR_PTR(-EINVAL);
 314
 315         if (!desc->ops->set_event || !desc->ops->get_event)
 316                 return ERR_PTR(-EINVAL);
 317
 318         edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
 319         if (!edev)
 320                 return ERR_PTR(-ENOMEM);
 321
 322         mutex_init(&edev->lock);
 323         edev->desc = desc;
 324         edev->enable_count = 0;
 325         edev->dev.parent = dev;
 326         edev->dev.class = devfreq_event_class;
 327         edev->dev.release = devfreq_event_release_edev;
 328
 329         dev_set_name(&edev->dev, "event%d", atomic_inc_return(&event_no));
 330         ret = device_register(&edev->dev);
 331         if (ret < 0) {
 332                 put_device(&edev->dev);
 333                 return ERR_PTR(ret);
 334         }
 335         dev_set_drvdata(&edev->dev, edev);
 336
 337         INIT_LIST_HEAD(&edev->node);
 338
 339         mutex_lock(&devfreq_event_list_lock);
 340         list_add(&edev->node, &devfreq_event_list);
 341         mutex_unlock(&devfreq_event_list_lock);
 342
 343         return edev;
 344 }
 345 EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
 346
 347 /**
 348  * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
 349  * @edev        : the devfreq-event device
 350  *
 351  * Note that this function removes the registered devfreq-event device.
 352  */
 353 int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
 354 {
 355         if (!edev)
 356                 return -EINVAL;
 357
 358         WARN_ON(edev->enable_count);
 359
 360         mutex_lock(&devfreq_event_list_lock);
 361         list_del(&edev->node);
 362         mutex_unlock(&devfreq_event_list_lock);
 363
 364         device_unregister(&edev->dev);
 365
 366         return 0;
 367 }
 368 EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
 369
 370 static int devm_devfreq_event_match(struct device *dev, void *res, void *data)
 371 {
 372         struct devfreq_event_dev **r = res;
 373
 374         if (WARN_ON(!r || !*r))
 375                 return 0;
 376
 377         return *r == data;
 378 }
 379
 380 static void devm_devfreq_event_release(struct device *dev, void *res)
 381 {
 382         devfreq_event_remove_edev(*(struct devfreq_event_dev **)res);
 383 }
 384
 385 /**
 386  * devm_devfreq_event_add_edev() - Resource-managed devfreq_event_add_edev()
 387  * @dev         : the device owning the devfreq-event device being created
 388  * @desc        : the devfreq-event device's decriptor which include essential
 389  *                data for devfreq-event device.
 390  *
 391  * Note that this function manages automatically the memory of devfreq-event
 392  * device using device resource management and simplify the free operation
 393  * for memory of devfreq-event device.
 394  */
 395 struct devfreq_event_dev *devm_devfreq_event_add_edev(struct device *dev,
 396                                                 struct devfreq_event_desc *desc)
 397 {
 398         struct devfreq_event_dev **ptr, *edev;
 399
 400         ptr = devres_alloc(devm_devfreq_event_release, sizeof(*ptr),
 401                                 GFP_KERNEL);
 402         if (!ptr)
 403                 return ERR_PTR(-ENOMEM);
 404
 405         edev = devfreq_event_add_edev(dev, desc);
 406         if (IS_ERR(edev)) {
 407                 devres_free(ptr);
 408                 return ERR_PTR(-ENOMEM);
 409         }
 410
 411         *ptr = edev;
 412         devres_add(dev, ptr);
 413
 414         return edev;
 415 }
 416 EXPORT_SYMBOL_GPL(devm_devfreq_event_add_edev);
 417
 418 /**
 419  * devm_devfreq_event_remove_edev()- Resource-managed devfreq_event_remove_edev()
 420  * @dev         : the device owning the devfreq-event device being created
 421  * @edev        : the devfreq-event device
 422  *
 423  * Note that this function manages automatically the memory of devfreq-event
 424  * device using device resource management.
 425  */
 426 void devm_devfreq_event_remove_edev(struct device *dev,
 427                                 struct devfreq_event_dev *edev)
 428 {
 429         WARN_ON(devres_release(dev, devm_devfreq_event_release,
 430                                devm_devfreq_event_match, edev));
 431 }
 432 EXPORT_SYMBOL_GPL(devm_devfreq_event_remove_edev);
 433
 434 /*
 435  * Device attributes for devfreq-event class.
 436  */
 437 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 438                          char *buf)
 439 {
 440         struct devfreq_event_dev *edev = to_devfreq_event(dev);
 441
 442         if (!edev || !edev->desc)
 443                 return -EINVAL;
 444
 445         return sprintf(buf, "%s\n", edev->desc->name);
 446 }
 447 static DEVICE_ATTR_RO(name);
 448
 449 static ssize_t enable_count_show(struct device *dev,
 450                                   struct device_attribute *attr, char *buf)
 451 {
 452         struct devfreq_event_dev *edev = to_devfreq_event(dev);
 453
 454         if (!edev || !edev->desc)
 455                 return -EINVAL;
 456
 457         return sprintf(buf, "%d\n", edev->enable_count);
 458 }
 459 static DEVICE_ATTR_RO(enable_count);
 460
 461 static struct attribute *devfreq_event_attrs[] = {
 462         &dev_attr_name.attr,
 463         &dev_attr_enable_count.attr,
 464         NULL,
 465 };
 466 ATTRIBUTE_GROUPS(devfreq_event);
 467
 468 static int __init devfreq_event_init(void)
 469 {
 470         devfreq_event_class = class_create(THIS_MODULE, "devfreq-event");
 471         if (IS_ERR(devfreq_event_class)) {
 472                 pr_err("%s: couldn't create class\n", __FILE__);
 473                 return PTR_ERR(devfreq_event_class);
 474         }
 475
 476         devfreq_event_class->dev_groups = devfreq_event_groups;
 477
 478         return 0;
 479 }
 480 subsys_initcall(devfreq_event_init);