drivers/devfreq/devfreq.c

   1 /*
   2  * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
   3  *          for Non-CPU Devices.
   4  *
   5  * Copyright (C) 2011 Samsung Electronics
   6  *      MyungJoo Ham <myungjoo.ham@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/errno.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/module.h>
  19 #include <linux/slab.h>
  20 #include <linux/stat.h>
  21 #include <linux/pm_opp.h>
  22 #include <linux/devfreq.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/list.h>
  26 #include <linux/printk.h>
  27 #include <linux/hrtimer.h>
  28 #include <linux/of.h>
  29 #include "governor.h"
  30
  31 static struct class *devfreq_class;
  32
  33 /*
  34  * devfreq core provides delayed work based load monitoring helper
  35  * functions. Governors can use these or can implement their own
  36  * monitoring mechanism.
  37  */
  38 static struct workqueue_struct *devfreq_wq;
  39
  40 /* The list of all device-devfreq governors */
  41 static LIST_HEAD(devfreq_governor_list);
  42 /* The list of all device-devfreq */
  43 static LIST_HEAD(devfreq_list);
  44 static DEFINE_MUTEX(devfreq_list_lock);
  45
  46 /**
  47  * find_device_devfreq() - find devfreq struct using device pointer
  48  * @dev:        device pointer used to lookup device devfreq.
  49  *
  50  * Search the list of device devfreqs and return the matched device's
  51  * devfreq info. devfreq_list_lock should be held by the caller.
  52  */
  53 static struct devfreq *find_device_devfreq(struct device *dev)
  54 {
  55         struct devfreq *tmp_devfreq;
  56
  57         if (IS_ERR_OR_NULL(dev)) {
  58                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  59                 return ERR_PTR(-EINVAL);
  60         }
  61         WARN(!mutex_is_locked(&devfreq_list_lock),
  62              "devfreq_list_lock must be locked.");
  63
  64         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  65                 if (tmp_devfreq->dev.parent == dev)
  66                         return tmp_devfreq;
  67         }
  68
  69         return ERR_PTR(-ENODEV);
  70 }
  71
  72 /**
  73  * devfreq_get_freq_level() - Lookup freq_table for the frequency
  74  * @devfreq:    the devfreq instance
  75  * @freq:       the target frequency
  76  */
  77 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
  78 {
  79         int lev;
  80
  81         for (lev = 0; lev < devfreq->profile->max_state; lev++)
  82                 if (freq == devfreq->profile->freq_table[lev])
  83                         return lev;
  84
  85         return -EINVAL;
  86 }
  87
  88 /**
  89  * devfreq_update_status() - Update statistics of devfreq behavior
  90  * @devfreq:    the devfreq instance
  91  * @freq:       the update target frequency
  92  */
  93 static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
  94 {
  95         int lev, prev_lev, ret = 0;
  96         unsigned long cur_time;
  97
  98         cur_time = jiffies;
  99
 100         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 101         if (prev_lev < 0) {
 102                 ret = prev_lev;
 103                 goto out;
 104         }
 105
 106         devfreq->time_in_state[prev_lev] +=
 107                          cur_time - devfreq->last_stat_updated;
 108
 109         lev = devfreq_get_freq_level(devfreq, freq);
 110         if (lev < 0) {
 111                 ret = lev;
 112                 goto out;
 113         }
 114
 115         if (lev != prev_lev) {
 116                 devfreq->trans_table[(prev_lev *
 117                                 devfreq->profile->max_state) + lev]++;
 118                 devfreq->total_trans++;
 119         }
 120
 121 out:
 122         devfreq->last_stat_updated = cur_time;
 123         return ret;
 124 }
 125
 126 /**
 127  * find_devfreq_governor() - find devfreq governor from name
 128  * @name:       name of the governor
 129  *
 130  * Search the list of devfreq governors and return the matched
 131  * governor's pointer. devfreq_list_lock should be held by the caller.
 132  */
 133 static struct devfreq_governor *find_devfreq_governor(const char *name)
 134 {
 135         struct devfreq_governor *tmp_governor;
 136
 137         if (IS_ERR_OR_NULL(name)) {
 138                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 139                 return ERR_PTR(-EINVAL);
 140         }
 141         WARN(!mutex_is_locked(&devfreq_list_lock),
 142              "devfreq_list_lock must be locked.");
 143
 144         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 145                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 146                         return tmp_governor;
 147         }
 148
 149         return ERR_PTR(-ENODEV);
 150 }
 151
 152 static int devfreq_notify_transition(struct devfreq *devfreq,
 153                 struct devfreq_freqs *freqs, unsigned int state)
 154 {
 155         if (!devfreq)
 156                 return -EINVAL;
 157
 158         switch (state) {
 159         case DEVFREQ_PRECHANGE:
 160                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 161                                 DEVFREQ_PRECHANGE, freqs);
 162                 break;
 163
 164         case DEVFREQ_POSTCHANGE:
 165                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 166                                 DEVFREQ_POSTCHANGE, freqs);
 167                 break;
 168         default:
 169                 return -EINVAL;
 170         }
 171
 172         return 0;
 173 }
 174
 175 /* Load monitoring helper functions for governors use */
 176
 177 /**
 178  * update_devfreq() - Reevaluate the device and configure frequency.
 179  * @devfreq:    the devfreq instance.
 180  *
 181  * Note: Lock devfreq->lock before calling update_devfreq
 182  *       This function is exported for governors.
 183  */
 184 int update_devfreq(struct devfreq *devfreq)
 185 {
 186         struct devfreq_freqs freqs;
 187         unsigned long freq, cur_freq;
 188         int err = 0;
 189         u32 flags = 0;
 190
 191         if (!mutex_is_locked(&devfreq->lock)) {
 192                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 193                 return -EINVAL;
 194         }
 195
 196         if (!devfreq->governor)
 197                 return -EINVAL;
 198
 199         /* Reevaluate the proper frequency */
 200         err = devfreq->governor->get_target_freq(devfreq, &freq);
 201         if (err)
 202                 return err;
 203
 204         /*
 205          * Adjust the frequency with user freq and QoS.
 206          *
 207          * List from the highest priority
 208          * max_freq
 209          * min_freq
 210          */
 211
 212         if (devfreq->min_freq && freq < devfreq->min_freq) {
 213                 freq = devfreq->min_freq;
 214                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 215         }
 216         if (devfreq->max_freq && freq > devfreq->max_freq) {
 217                 freq = devfreq->max_freq;
 218                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 219         }
 220
 221         if (devfreq->profile->get_cur_freq)
 222                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 223         else
 224                 cur_freq = devfreq->previous_freq;
 225
 226         freqs.old = cur_freq;
 227         freqs.new = freq;
 228         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 229
 230         err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 231         if (err) {
 232                 freqs.new = cur_freq;
 233                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 234                 return err;
 235         }
 236
 237         freqs.new = freq;
 238         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 239
 240         if (devfreq->profile->freq_table)
 241                 if (devfreq_update_status(devfreq, freq))
 242                         dev_err(&devfreq->dev,
 243                                 "Couldn't update frequency transition information.\n");
 244
 245         devfreq->previous_freq = freq;
 246         return err;
 247 }
 248 EXPORT_SYMBOL(update_devfreq);
 249
 250 /**
 251  * devfreq_monitor() - Periodically poll devfreq objects.
 252  * @work:       the work struct used to run devfreq_monitor periodically.
 253  *
 254  */
 255 static void devfreq_monitor(struct work_struct *work)
 256 {
 257         int err;
 258         struct devfreq *devfreq = container_of(work,
 259                                         struct devfreq, work.work);
 260
 261         mutex_lock(&devfreq->lock);
 262         err = update_devfreq(devfreq);
 263         if (err)
 264                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 265
 266         queue_delayed_work(devfreq_wq, &devfreq->work,
 267                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 268         mutex_unlock(&devfreq->lock);
 269 }
 270
 271 /**
 272  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 273  * @devfreq:    the devfreq instance.
 274  *
 275  * Helper function for starting devfreq device load monitoing. By
 276  * default delayed work based monitoring is supported. Function
 277  * to be called from governor in response to DEVFREQ_GOV_START
 278  * event when device is added to devfreq framework.
 279  */
 280 void devfreq_monitor_start(struct devfreq *devfreq)
 281 {
 282         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 283         if (devfreq->profile->polling_ms)
 284                 queue_delayed_work(devfreq_wq, &devfreq->work,
 285                         msecs_to_jiffies(devfreq->profile->polling_ms));
 286 }
 287 EXPORT_SYMBOL(devfreq_monitor_start);
 288
 289 /**
 290  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 291  * @devfreq:    the devfreq instance.
 292  *
 293  * Helper function to stop devfreq device load monitoing. Function
 294  * to be called from governor in response to DEVFREQ_GOV_STOP
 295  * event when device is removed from devfreq framework.
 296  */
 297 void devfreq_monitor_stop(struct devfreq *devfreq)
 298 {
 299         cancel_delayed_work_sync(&devfreq->work);
 300 }
 301 EXPORT_SYMBOL(devfreq_monitor_stop);
 302
 303 /**
 304  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 305  * @devfreq:    the devfreq instance.
 306  *
 307  * Helper function to suspend devfreq device load monitoing. Function
 308  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 309  * event or when polling interval is set to zero.
 310  *
 311  * Note: Though this function is same as devfreq_monitor_stop(),
 312  * intentionally kept separate to provide hooks for collecting
 313  * transition statistics.
 314  */
 315 void devfreq_monitor_suspend(struct devfreq *devfreq)
 316 {
 317         mutex_lock(&devfreq->lock);
 318         if (devfreq->stop_polling) {
 319                 mutex_unlock(&devfreq->lock);
 320                 return;
 321         }
 322
 323         devfreq_update_status(devfreq, devfreq->previous_freq);
 324         devfreq->stop_polling = true;
 325         mutex_unlock(&devfreq->lock);
 326         cancel_delayed_work_sync(&devfreq->work);
 327 }
 328 EXPORT_SYMBOL(devfreq_monitor_suspend);
 329
 330 /**
 331  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 332  * @devfreq:    the devfreq instance.
 333  *
 334  * Helper function to resume devfreq device load monitoing. Function
 335  * to be called from governor in response to DEVFREQ_GOV_RESUME
 336  * event or when polling interval is set to non-zero.
 337  */
 338 void devfreq_monitor_resume(struct devfreq *devfreq)
 339 {
 340         unsigned long freq;
 341
 342         mutex_lock(&devfreq->lock);
 343         if (!devfreq->stop_polling)
 344                 goto out;
 345
 346         if (!delayed_work_pending(&devfreq->work) &&
 347                         devfreq->profile->polling_ms)
 348                 queue_delayed_work(devfreq_wq, &devfreq->work,
 349                         msecs_to_jiffies(devfreq->profile->polling_ms));
 350
 351         devfreq->last_stat_updated = jiffies;
 352         devfreq->stop_polling = false;
 353
 354         if (devfreq->profile->get_cur_freq &&
 355                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 356                 devfreq->previous_freq = freq;
 357
 358 out:
 359         mutex_unlock(&devfreq->lock);
 360 }
 361 EXPORT_SYMBOL(devfreq_monitor_resume);
 362
 363 /**
 364  * devfreq_interval_update() - Update device devfreq monitoring interval
 365  * @devfreq:    the devfreq instance.
 366  * @delay:      new polling interval to be set.
 367  *
 368  * Helper function to set new load monitoring polling interval. Function
 369  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 370  */
 371 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 372 {
 373         unsigned int cur_delay = devfreq->profile->polling_ms;
 374         unsigned int new_delay = *delay;
 375
 376         mutex_lock(&devfreq->lock);
 377         devfreq->profile->polling_ms = new_delay;
 378
 379         if (devfreq->stop_polling)
 380                 goto out;
 381
 382         /* if new delay is zero, stop polling */
 383         if (!new_delay) {
 384                 mutex_unlock(&devfreq->lock);
 385                 cancel_delayed_work_sync(&devfreq->work);
 386                 return;
 387         }
 388
 389         /* if current delay is zero, start polling with new delay */
 390         if (!cur_delay) {
 391                 queue_delayed_work(devfreq_wq, &devfreq->work,
 392                         msecs_to_jiffies(devfreq->profile->polling_ms));
 393                 goto out;
 394         }
 395
 396         /* if current delay is greater than new delay, restart polling */
 397         if (cur_delay > new_delay) {
 398                 mutex_unlock(&devfreq->lock);
 399                 cancel_delayed_work_sync(&devfreq->work);
 400                 mutex_lock(&devfreq->lock);
 401                 if (!devfreq->stop_polling)
 402                         queue_delayed_work(devfreq_wq, &devfreq->work,
 403                               msecs_to_jiffies(devfreq->profile->polling_ms));
 404         }
 405 out:
 406         mutex_unlock(&devfreq->lock);
 407 }
 408 EXPORT_SYMBOL(devfreq_interval_update);
 409
 410 /**
 411  * devfreq_notifier_call() - Notify that the device frequency requirements
 412  *                         has been changed out of devfreq framework.
 413  * @nb:         the notifier_block (supposed to be devfreq->nb)
 414  * @type:       not used
 415  * @devp:       not used
 416  *
 417  * Called by a notifier that uses devfreq->nb.
 418  */
 419 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 420                                  void *devp)
 421 {
 422         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 423         int ret;
 424
 425         mutex_lock(&devfreq->lock);
 426         ret = update_devfreq(devfreq);
 427         mutex_unlock(&devfreq->lock);
 428
 429         return ret;
 430 }
 431
 432 /**
 433  * _remove_devfreq() - Remove devfreq from the list and release its resources.
 434  * @devfreq:    the devfreq struct
 435  */
 436 static void _remove_devfreq(struct devfreq *devfreq)
 437 {
 438         mutex_lock(&devfreq_list_lock);
 439         if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
 440                 mutex_unlock(&devfreq_list_lock);
 441                 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
 442                 return;
 443         }
 444         list_del(&devfreq->node);
 445         mutex_unlock(&devfreq_list_lock);
 446
 447         if (devfreq->governor)
 448                 devfreq->governor->event_handler(devfreq,
 449                                                  DEVFREQ_GOV_STOP, NULL);
 450
 451         if (devfreq->profile->exit)
 452                 devfreq->profile->exit(devfreq->dev.parent);
 453
 454         mutex_destroy(&devfreq->lock);
 455         kfree(devfreq);
 456 }
 457
 458 /**
 459  * devfreq_dev_release() - Callback for struct device to release the device.
 460  * @dev:        the devfreq device
 461  *
 462  * This calls _remove_devfreq() if _remove_devfreq() is not called.
 463  */
 464 static void devfreq_dev_release(struct device *dev)
 465 {
 466         struct devfreq *devfreq = to_devfreq(dev);
 467
 468         _remove_devfreq(devfreq);
 469 }
 470
 471 /**
 472  * devfreq_add_device() - Add devfreq feature to the device
 473  * @dev:        the device to add devfreq feature.
 474  * @profile:    device-specific profile to run devfreq.
 475  * @governor_name:      name of the policy to choose frequency.
 476  * @data:       private data for the governor. The devfreq framework does not
 477  *              touch this value.
 478  */
 479 struct devfreq *devfreq_add_device(struct device *dev,
 480                                    struct devfreq_dev_profile *profile,
 481                                    const char *governor_name,
 482                                    void *data)
 483 {
 484         struct devfreq *devfreq;
 485         struct devfreq_governor *governor;
 486         int err = 0;
 487
 488         if (!dev || !profile || !governor_name) {
 489                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 490                 return ERR_PTR(-EINVAL);
 491         }
 492
 493         mutex_lock(&devfreq_list_lock);
 494         devfreq = find_device_devfreq(dev);
 495         mutex_unlock(&devfreq_list_lock);
 496         if (!IS_ERR(devfreq)) {
 497                 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
 498                 err = -EINVAL;
 499                 goto err_out;
 500         }
 501
 502         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 503         if (!devfreq) {
 504                 dev_err(dev, "%s: Unable to create devfreq for the device\n",
 505                         __func__);
 506                 err = -ENOMEM;
 507                 goto err_out;
 508         }
 509
 510         mutex_init(&devfreq->lock);
 511         mutex_lock(&devfreq->lock);
 512         devfreq->dev.parent = dev;
 513         devfreq->dev.class = devfreq_class;
 514         devfreq->dev.release = devfreq_dev_release;
 515         devfreq->profile = profile;
 516         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 517         devfreq->previous_freq = profile->initial_freq;
 518         devfreq->data = data;
 519         devfreq->nb.notifier_call = devfreq_notifier_call;
 520
 521         devfreq->trans_table =  devm_kzalloc(dev, sizeof(unsigned int) *
 522                                                 devfreq->profile->max_state *
 523                                                 devfreq->profile->max_state,
 524                                                 GFP_KERNEL);
 525         devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned long) *
 526                                                 devfreq->profile->max_state,
 527                                                 GFP_KERNEL);
 528         devfreq->last_stat_updated = jiffies;
 529
 530         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 531         err = device_register(&devfreq->dev);
 532         if (err) {
 533                 put_device(&devfreq->dev);
 534                 mutex_unlock(&devfreq->lock);
 535                 goto err_out;
 536         }
 537
 538         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 539
 540         mutex_unlock(&devfreq->lock);
 541
 542         mutex_lock(&devfreq_list_lock);
 543         list_add(&devfreq->node, &devfreq_list);
 544
 545         governor = find_devfreq_governor(devfreq->governor_name);
 546         if (!IS_ERR(governor))
 547                 devfreq->governor = governor;
 548         if (devfreq->governor)
 549                 err = devfreq->governor->event_handler(devfreq,
 550                                         DEVFREQ_GOV_START, NULL);
 551         mutex_unlock(&devfreq_list_lock);
 552         if (err) {
 553                 dev_err(dev, "%s: Unable to start governor for the device\n",
 554                         __func__);
 555                 goto err_init;
 556         }
 557
 558         return devfreq;
 559
 560 err_init:
 561         list_del(&devfreq->node);
 562         device_unregister(&devfreq->dev);
 563         kfree(devfreq);
 564 err_out:
 565         return ERR_PTR(err);
 566 }
 567 EXPORT_SYMBOL(devfreq_add_device);
 568
 569 /**
 570  * devfreq_remove_device() - Remove devfreq feature from a device.
 571  * @devfreq:    the devfreq instance to be removed
 572  *
 573  * The opposite of devfreq_add_device().
 574  */
 575 int devfreq_remove_device(struct devfreq *devfreq)
 576 {
 577         if (!devfreq)
 578                 return -EINVAL;
 579
 580         device_unregister(&devfreq->dev);
 581         put_device(&devfreq->dev);
 582
 583         return 0;
 584 }
 585 EXPORT_SYMBOL(devfreq_remove_device);
 586
 587 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 588 {
 589         struct devfreq **r = res;
 590
 591         if (WARN_ON(!r || !*r))
 592                 return 0;
 593
 594         return *r == data;
 595 }
 596
 597 static void devm_devfreq_dev_release(struct device *dev, void *res)
 598 {
 599         devfreq_remove_device(*(struct devfreq **)res);
 600 }
 601
 602 /**
 603  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 604  * @dev:        the device to add devfreq feature.
 605  * @profile:    device-specific profile to run devfreq.
 606  * @governor_name:      name of the policy to choose frequency.
 607  * @data:       private data for the governor. The devfreq framework does not
 608  *              touch this value.
 609  *
 610  * This function manages automatically the memory of devfreq device using device
 611  * resource management and simplify the free operation for memory of devfreq
 612  * device.
 613  */
 614 struct devfreq *devm_devfreq_add_device(struct device *dev,
 615                                         struct devfreq_dev_profile *profile,
 616                                         const char *governor_name,
 617                                         void *data)
 618 {
 619         struct devfreq **ptr, *devfreq;
 620
 621         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 622         if (!ptr)
 623                 return ERR_PTR(-ENOMEM);
 624
 625         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 626         if (IS_ERR(devfreq)) {
 627                 devres_free(ptr);
 628                 return ERR_PTR(-ENOMEM);
 629         }
 630
 631         *ptr = devfreq;
 632         devres_add(dev, ptr);
 633
 634         return devfreq;
 635 }
 636 EXPORT_SYMBOL(devm_devfreq_add_device);
 637
 638 #ifdef CONFIG_OF
 639 /*
 640  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 641  * @dev - instance to the given device
 642  * @index - index into list of devfreq
 643  *
 644  * return the instance of devfreq device
 645  */
 646 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 647 {
 648         struct device_node *node;
 649         struct devfreq *devfreq;
 650
 651         if (!dev)
 652                 return ERR_PTR(-EINVAL);
 653
 654         if (!dev->of_node)
 655                 return ERR_PTR(-EINVAL);
 656
 657         node = of_parse_phandle(dev->of_node, "devfreq", index);
 658         if (!node)
 659                 return ERR_PTR(-ENODEV);
 660
 661         mutex_lock(&devfreq_list_lock);
 662         list_for_each_entry(devfreq, &devfreq_list, node) {
 663                 if (devfreq->dev.parent
 664                         && devfreq->dev.parent->of_node == node) {
 665                         mutex_unlock(&devfreq_list_lock);
 666                         of_node_put(node);
 667                         return devfreq;
 668                 }
 669         }
 670         mutex_unlock(&devfreq_list_lock);
 671         of_node_put(node);
 672
 673         return ERR_PTR(-EPROBE_DEFER);
 674 }
 675 #else
 676 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 677 {
 678         return ERR_PTR(-ENODEV);
 679 }
 680 #endif /* CONFIG_OF */
 681 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 682
 683 /**
 684  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 685  * @dev:        the device to add devfreq feature.
 686  * @devfreq:    the devfreq instance to be removed
 687  */
 688 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 689 {
 690         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 691                                devm_devfreq_dev_match, devfreq));
 692 }
 693 EXPORT_SYMBOL(devm_devfreq_remove_device);
 694
 695 /**
 696  * devfreq_suspend_device() - Suspend devfreq of a device.
 697  * @devfreq: the devfreq instance to be suspended
 698  *
 699  * This function is intended to be called by the pm callbacks
 700  * (e.g., runtime_suspend, suspend) of the device driver that
 701  * holds the devfreq.
 702  */
 703 int devfreq_suspend_device(struct devfreq *devfreq)
 704 {
 705         if (!devfreq)
 706                 return -EINVAL;
 707
 708         if (!devfreq->governor)
 709                 return 0;
 710
 711         return devfreq->governor->event_handler(devfreq,
 712                                 DEVFREQ_GOV_SUSPEND, NULL);
 713 }
 714 EXPORT_SYMBOL(devfreq_suspend_device);
 715
 716 /**
 717  * devfreq_resume_device() - Resume devfreq of a device.
 718  * @devfreq: the devfreq instance to be resumed
 719  *
 720  * This function is intended to be called by the pm callbacks
 721  * (e.g., runtime_resume, resume) of the device driver that
 722  * holds the devfreq.
 723  */
 724 int devfreq_resume_device(struct devfreq *devfreq)
 725 {
 726         if (!devfreq)
 727                 return -EINVAL;
 728
 729         if (!devfreq->governor)
 730                 return 0;
 731
 732         return devfreq->governor->event_handler(devfreq,
 733                                 DEVFREQ_GOV_RESUME, NULL);
 734 }
 735 EXPORT_SYMBOL(devfreq_resume_device);
 736
 737 /**
 738  * devfreq_add_governor() - Add devfreq governor
 739  * @governor:   the devfreq governor to be added
 740  */
 741 int devfreq_add_governor(struct devfreq_governor *governor)
 742 {
 743         struct devfreq_governor *g;
 744         struct devfreq *devfreq;
 745         int err = 0;
 746
 747         if (!governor) {
 748                 pr_err("%s: Invalid parameters.\n", __func__);
 749                 return -EINVAL;
 750         }
 751
 752         mutex_lock(&devfreq_list_lock);
 753         g = find_devfreq_governor(governor->name);
 754         if (!IS_ERR(g)) {
 755                 pr_err("%s: governor %s already registered\n", __func__,
 756                        g->name);
 757                 err = -EINVAL;
 758                 goto err_out;
 759         }
 760
 761         list_add(&governor->node, &devfreq_governor_list);
 762
 763         list_for_each_entry(devfreq, &devfreq_list, node) {
 764                 int ret = 0;
 765                 struct device *dev = devfreq->dev.parent;
 766
 767                 if (!strncmp(devfreq->governor_name, governor->name,
 768                              DEVFREQ_NAME_LEN)) {
 769                         /* The following should never occur */
 770                         if (devfreq->governor) {
 771                                 dev_warn(dev,
 772                                          "%s: Governor %s already present\n",
 773                                          __func__, devfreq->governor->name);
 774                                 ret = devfreq->governor->event_handler(devfreq,
 775                                                         DEVFREQ_GOV_STOP, NULL);
 776                                 if (ret) {
 777                                         dev_warn(dev,
 778                                                  "%s: Governor %s stop = %d\n",
 779                                                  __func__,
 780                                                  devfreq->governor->name, ret);
 781                                 }
 782                                 /* Fall through */
 783                         }
 784                         devfreq->governor = governor;
 785                         ret = devfreq->governor->event_handler(devfreq,
 786                                                 DEVFREQ_GOV_START, NULL);
 787                         if (ret) {
 788                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 789                                          __func__, devfreq->governor->name,
 790                                          ret);
 791                         }
 792                 }
 793         }
 794
 795 err_out:
 796         mutex_unlock(&devfreq_list_lock);
 797
 798         return err;
 799 }
 800 EXPORT_SYMBOL(devfreq_add_governor);
 801
 802 /**
 803  * devfreq_remove_device() - Remove devfreq feature from a device.
 804  * @governor:   the devfreq governor to be removed
 805  */
 806 int devfreq_remove_governor(struct devfreq_governor *governor)
 807 {
 808         struct devfreq_governor *g;
 809         struct devfreq *devfreq;
 810         int err = 0;
 811
 812         if (!governor) {
 813                 pr_err("%s: Invalid parameters.\n", __func__);
 814                 return -EINVAL;
 815         }
 816
 817         mutex_lock(&devfreq_list_lock);
 818         g = find_devfreq_governor(governor->name);
 819         if (IS_ERR(g)) {
 820                 pr_err("%s: governor %s not registered\n", __func__,
 821                        governor->name);
 822                 err = PTR_ERR(g);
 823                 goto err_out;
 824         }
 825         list_for_each_entry(devfreq, &devfreq_list, node) {
 826                 int ret;
 827                 struct device *dev = devfreq->dev.parent;
 828
 829                 if (!strncmp(devfreq->governor_name, governor->name,
 830                              DEVFREQ_NAME_LEN)) {
 831                         /* we should have a devfreq governor! */
 832                         if (!devfreq->governor) {
 833                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 834                                          __func__, governor->name);
 835                                 continue;
 836                                 /* Fall through */
 837                         }
 838                         ret = devfreq->governor->event_handler(devfreq,
 839                                                 DEVFREQ_GOV_STOP, NULL);
 840                         if (ret) {
 841                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 842                                          __func__, devfreq->governor->name,
 843                                          ret);
 844                         }
 845                         devfreq->governor = NULL;
 846                 }
 847         }
 848
 849         list_del(&governor->node);
 850 err_out:
 851         mutex_unlock(&devfreq_list_lock);
 852
 853         return err;
 854 }
 855 EXPORT_SYMBOL(devfreq_remove_governor);
 856
 857 static ssize_t governor_show(struct device *dev,
 858                              struct device_attribute *attr, char *buf)
 859 {
 860         if (!to_devfreq(dev)->governor)
 861                 return -EINVAL;
 862
 863         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 864 }
 865
 866 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 867                               const char *buf, size_t count)
 868 {
 869         struct devfreq *df = to_devfreq(dev);
 870         int ret;
 871         char str_governor[DEVFREQ_NAME_LEN + 1];
 872         struct devfreq_governor *governor;
 873
 874         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 875         if (ret != 1)
 876                 return -EINVAL;
 877
 878         mutex_lock(&devfreq_list_lock);
 879         governor = find_devfreq_governor(str_governor);
 880         if (IS_ERR(governor)) {
 881                 ret = PTR_ERR(governor);
 882                 goto out;
 883         }
 884         if (df->governor == governor) {
 885                 ret = 0;
 886                 goto out;
 887         }
 888
 889         if (df->governor) {
 890                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
 891                 if (ret) {
 892                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
 893                                  __func__, df->governor->name, ret);
 894                         goto out;
 895                 }
 896         }
 897         df->governor = governor;
 898         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
 899         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
 900         if (ret)
 901                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
 902                          __func__, df->governor->name, ret);
 903 out:
 904         mutex_unlock(&devfreq_list_lock);
 905
 906         if (!ret)
 907                 ret = count;
 908         return ret;
 909 }
 910 static DEVICE_ATTR_RW(governor);
 911
 912 static ssize_t available_governors_show(struct device *d,
 913                                         struct device_attribute *attr,
 914                                         char *buf)
 915 {
 916         struct devfreq_governor *tmp_governor;
 917         ssize_t count = 0;
 918
 919         mutex_lock(&devfreq_list_lock);
 920         list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
 921                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
 922                                    "%s ", tmp_governor->name);
 923         mutex_unlock(&devfreq_list_lock);
 924
 925         /* Truncate the trailing space */
 926         if (count)
 927                 count--;
 928
 929         count += sprintf(&buf[count], "\n");
 930
 931         return count;
 932 }
 933 static DEVICE_ATTR_RO(available_governors);
 934
 935 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
 936                              char *buf)
 937 {
 938         unsigned long freq;
 939         struct devfreq *devfreq = to_devfreq(dev);
 940
 941         if (devfreq->profile->get_cur_freq &&
 942                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 943                         return sprintf(buf, "%lu\n", freq);
 944
 945         return sprintf(buf, "%lu\n", devfreq->previous_freq);
 946 }
 947 static DEVICE_ATTR_RO(cur_freq);
 948
 949 static ssize_t target_freq_show(struct device *dev,
 950                                 struct device_attribute *attr, char *buf)
 951 {
 952         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
 953 }
 954 static DEVICE_ATTR_RO(target_freq);
 955
 956 static ssize_t polling_interval_show(struct device *dev,
 957                                      struct device_attribute *attr, char *buf)
 958 {
 959         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
 960 }
 961
 962 static ssize_t polling_interval_store(struct device *dev,
 963                                       struct device_attribute *attr,
 964                                       const char *buf, size_t count)
 965 {
 966         struct devfreq *df = to_devfreq(dev);
 967         unsigned int value;
 968         int ret;
 969
 970         if (!df->governor)
 971                 return -EINVAL;
 972
 973         ret = sscanf(buf, "%u", &value);
 974         if (ret != 1)
 975                 return -EINVAL;
 976
 977         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
 978         ret = count;
 979
 980         return ret;
 981 }
 982 static DEVICE_ATTR_RW(polling_interval);
 983
 984 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
 985                               const char *buf, size_t count)
 986 {
 987         struct devfreq *df = to_devfreq(dev);
 988         unsigned long value;
 989         int ret;
 990         unsigned long max;
 991
 992         ret = sscanf(buf, "%lu", &value);
 993         if (ret != 1)
 994                 return -EINVAL;
 995
 996         mutex_lock(&df->lock);
 997         max = df->max_freq;
 998         if (value && max && value > max) {
 999                 ret = -EINVAL;
1000                 goto unlock;
1001         }
1002
1003         df->min_freq = value;
1004         update_devfreq(df);
1005         ret = count;
1006 unlock:
1007         mutex_unlock(&df->lock);
1008         return ret;
1009 }
1010
1011 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1012                              char *buf)
1013 {
1014         return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq);
1015 }
1016
1017 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1018                               const char *buf, size_t count)
1019 {
1020         struct devfreq *df = to_devfreq(dev);
1021         unsigned long value;
1022         int ret;
1023         unsigned long min;
1024
1025         ret = sscanf(buf, "%lu", &value);
1026         if (ret != 1)
1027                 return -EINVAL;
1028
1029         mutex_lock(&df->lock);
1030         min = df->min_freq;
1031         if (value && min && value < min) {
1032                 ret = -EINVAL;
1033                 goto unlock;
1034         }
1035
1036         df->max_freq = value;
1037         update_devfreq(df);
1038         ret = count;
1039 unlock:
1040         mutex_unlock(&df->lock);
1041         return ret;
1042 }
1043 static DEVICE_ATTR_RW(min_freq);
1044
1045 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1046                              char *buf)
1047 {
1048         return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
1049 }
1050 static DEVICE_ATTR_RW(max_freq);
1051
1052 static ssize_t available_frequencies_show(struct device *d,
1053                                           struct device_attribute *attr,
1054                                           char *buf)
1055 {
1056         struct devfreq *df = to_devfreq(d);
1057         struct device *dev = df->dev.parent;
1058         struct dev_pm_opp *opp;
1059         ssize_t count = 0;
1060         unsigned long freq = 0;
1061
1062         rcu_read_lock();
1063         do {
1064                 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1065                 if (IS_ERR(opp))
1066                         break;
1067
1068                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1069                                    "%lu ", freq);
1070                 freq++;
1071         } while (1);
1072         rcu_read_unlock();
1073
1074         /* Truncate the trailing space */
1075         if (count)
1076                 count--;
1077
1078         count += sprintf(&buf[count], "\n");
1079
1080         return count;
1081 }
1082 static DEVICE_ATTR_RO(available_frequencies);
1083
1084 static ssize_t trans_stat_show(struct device *dev,
1085                                struct device_attribute *attr, char *buf)
1086 {
1087         struct devfreq *devfreq = to_devfreq(dev);
1088         ssize_t len;
1089         int i, j;
1090         unsigned int max_state = devfreq->profile->max_state;
1091
1092         if (!devfreq->stop_polling &&
1093                         devfreq_update_status(devfreq, devfreq->previous_freq))
1094                 return 0;
1095
1096         len = sprintf(buf, "   From  :   To\n");
1097         len += sprintf(buf + len, "         :");
1098         for (i = 0; i < max_state; i++)
1099                 len += sprintf(buf + len, "%8u",
1100                                 devfreq->profile->freq_table[i]);
1101
1102         len += sprintf(buf + len, "   time(ms)\n");
1103
1104         for (i = 0; i < max_state; i++) {
1105                 if (devfreq->profile->freq_table[i]
1106                                         == devfreq->previous_freq) {
1107                         len += sprintf(buf + len, "*");
1108                 } else {
1109                         len += sprintf(buf + len, " ");
1110                 }
1111                 len += sprintf(buf + len, "%8u:",
1112                                 devfreq->profile->freq_table[i]);
1113                 for (j = 0; j < max_state; j++)
1114                         len += sprintf(buf + len, "%8u",
1115                                 devfreq->trans_table[(i * max_state) + j]);
1116                 len += sprintf(buf + len, "%10u\n",
1117                         jiffies_to_msecs(devfreq->time_in_state[i]));
1118         }
1119
1120         len += sprintf(buf + len, "Total transition : %u\n",
1121                                         devfreq->total_trans);
1122         return len;
1123 }
1124 static DEVICE_ATTR_RO(trans_stat);
1125
1126 static ssize_t load_show(struct device *dev, struct device_attribute *attr,
1127                          char *buf)
1128 {
1129         int err;
1130         struct devfreq *devfreq = to_devfreq(dev);
1131         struct devfreq_dev_status stat = devfreq->last_status;
1132         unsigned long freq;
1133         ssize_t len;
1134
1135         err = devfreq_update_stats(devfreq);
1136         if (err)
1137                 return err;
1138
1139         if (stat.total_time < stat.busy_time) {
1140                 err = devfreq_update_stats(devfreq);
1141                 if (err)
1142                         return err;
1143         };
1144
1145         if (!stat.total_time)
1146                 return 0;
1147
1148         len = sprintf(buf, "%lu", stat.busy_time * 100 / stat.total_time);
1149
1150         if (devfreq->profile->get_cur_freq &&
1151                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1152                         len += sprintf(buf + len, "@%luHz\n", freq);
1153         else
1154                 len += sprintf(buf + len, "@%luHz\n", devfreq->previous_freq);
1155
1156         return len;
1157 }
1158 static DEVICE_ATTR_RO(load);
1159
1160 static struct attribute *devfreq_attrs[] = {
1161         &dev_attr_governor.attr,
1162         &dev_attr_available_governors.attr,
1163         &dev_attr_cur_freq.attr,
1164         &dev_attr_available_frequencies.attr,
1165         &dev_attr_target_freq.attr,
1166         &dev_attr_polling_interval.attr,
1167         &dev_attr_min_freq.attr,
1168         &dev_attr_max_freq.attr,
1169         &dev_attr_trans_stat.attr,
1170         &dev_attr_load.attr,
1171         NULL,
1172 };
1173 ATTRIBUTE_GROUPS(devfreq);
1174
1175 static int __init devfreq_init(void)
1176 {
1177         devfreq_class = class_create(THIS_MODULE, "devfreq");
1178         if (IS_ERR(devfreq_class)) {
1179                 pr_err("%s: couldn't create class\n", __FILE__);
1180                 return PTR_ERR(devfreq_class);
1181         }
1182
1183         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1184         if (!devfreq_wq) {
1185                 class_destroy(devfreq_class);
1186                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1187                 return -ENOMEM;
1188         }
1189         devfreq_class->dev_groups = devfreq_groups;
1190
1191         return 0;
1192 }
1193 subsys_initcall(devfreq_init);
1194
1195 static void __exit devfreq_exit(void)
1196 {
1197         class_destroy(devfreq_class);
1198         destroy_workqueue(devfreq_wq);
1199 }
1200 module_exit(devfreq_exit);
1201
1202 /*
1203  * The followings are helper functions for devfreq user device drivers with
1204  * OPP framework.
1205  */
1206
1207 /**
1208  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1209  *                           freq value given to target callback.
1210  * @dev:        The devfreq user device. (parent of devfreq)
1211  * @freq:       The frequency given to target function
1212  * @flags:      Flags handed from devfreq framework.
1213  *
1214  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1215  * protected pointer. The reason for the same is that the opp pointer which is
1216  * returned will remain valid for use with opp_get_{voltage, freq} only while
1217  * under the locked area. The pointer returned must be used prior to unlocking
1218  * with rcu_read_unlock() to maintain the integrity of the pointer.
1219  */
1220 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1221                                            unsigned long *freq,
1222                                            u32 flags)
1223 {
1224         struct dev_pm_opp *opp;
1225
1226         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1227                 /* The freq is an upper bound. opp should be lower */
1228                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1229
1230                 /* If not available, use the closest opp */
1231                 if (opp == ERR_PTR(-ERANGE))
1232                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1233         } else {
1234                 /* The freq is an lower bound. opp should be higher */
1235                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1236
1237                 /* If not available, use the closest opp */
1238                 if (opp == ERR_PTR(-ERANGE))
1239                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1240         }
1241
1242         return opp;
1243 }
1244 EXPORT_SYMBOL(devfreq_recommended_opp);
1245
1246 /**
1247  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1248  *                                 for any changes in the OPP availability
1249  *                                 changes
1250  * @dev:        The devfreq user device. (parent of devfreq)
1251  * @devfreq:    The devfreq object.
1252  */
1253 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1254 {
1255         struct srcu_notifier_head *nh;
1256         int ret = 0;
1257
1258         rcu_read_lock();
1259         nh = dev_pm_opp_get_notifier(dev);
1260         if (IS_ERR(nh))
1261                 ret = PTR_ERR(nh);
1262         rcu_read_unlock();
1263         if (!ret)
1264                 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1265
1266         return ret;
1267 }
1268 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1269
1270 /**
1271  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1272  *                                   notified for any changes in the OPP
1273  *                                   availability changes anymore.
1274  * @dev:        The devfreq user device. (parent of devfreq)
1275  * @devfreq:    The devfreq object.
1276  *
1277  * At exit() callback of devfreq_dev_profile, this must be included if
1278  * devfreq_recommended_opp is used.
1279  */
1280 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1281 {
1282         struct srcu_notifier_head *nh;
1283         int ret = 0;
1284
1285         rcu_read_lock();
1286         nh = dev_pm_opp_get_notifier(dev);
1287         if (IS_ERR(nh))
1288                 ret = PTR_ERR(nh);
1289         rcu_read_unlock();
1290         if (!ret)
1291                 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1292
1293         return ret;
1294 }
1295 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1296
1297 static void devm_devfreq_opp_release(struct device *dev, void *res)
1298 {
1299         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1300 }
1301
1302 /**
1303  * devm_ devfreq_register_opp_notifier()
1304  *              - Resource-managed devfreq_register_opp_notifier()
1305  * @dev:        The devfreq user device. (parent of devfreq)
1306  * @devfreq:    The devfreq object.
1307  */
1308 int devm_devfreq_register_opp_notifier(struct device *dev,
1309                                        struct devfreq *devfreq)
1310 {
1311         struct devfreq **ptr;
1312         int ret;
1313
1314         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1315         if (!ptr)
1316                 return -ENOMEM;
1317
1318         ret = devfreq_register_opp_notifier(dev, devfreq);
1319         if (ret) {
1320                 devres_free(ptr);
1321                 return ret;
1322         }
1323
1324         *ptr = devfreq;
1325         devres_add(dev, ptr);
1326
1327         return 0;
1328 }
1329 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1330
1331 /**
1332  * devm_devfreq_unregister_opp_notifier()
1333  *              - Resource-managed devfreq_unregister_opp_notifier()
1334  * @dev:        The devfreq user device. (parent of devfreq)
1335  * @devfreq:    The devfreq object.
1336  */
1337 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1338                                          struct devfreq *devfreq)
1339 {
1340         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1341                                devm_devfreq_dev_match, devfreq));
1342 }
1343 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1344
1345 /**
1346  * devfreq_register_notifier() - Register a driver with devfreq
1347  * @devfreq:    The devfreq object.
1348  * @nb:         The notifier block to register.
1349  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1350  */
1351 int devfreq_register_notifier(struct devfreq *devfreq,
1352                                 struct notifier_block *nb,
1353                                 unsigned int list)
1354 {
1355         int ret = 0;
1356
1357         if (!devfreq)
1358                 return -EINVAL;
1359
1360         switch (list) {
1361         case DEVFREQ_TRANSITION_NOTIFIER:
1362                 ret = srcu_notifier_chain_register(
1363                                 &devfreq->transition_notifier_list, nb);
1364                 break;
1365         default:
1366                 ret = -EINVAL;
1367         }
1368
1369         return ret;
1370 }
1371 EXPORT_SYMBOL(devfreq_register_notifier);
1372
1373 /*
1374  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1375  * @devfreq:    The devfreq object.
1376  * @nb:         The notifier block to be unregistered.
1377  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1378  */
1379 int devfreq_unregister_notifier(struct devfreq *devfreq,
1380                                 struct notifier_block *nb,
1381                                 unsigned int list)
1382 {
1383         int ret = 0;
1384
1385         if (!devfreq)
1386                 return -EINVAL;
1387
1388         switch (list) {
1389         case DEVFREQ_TRANSITION_NOTIFIER:
1390                 ret = srcu_notifier_chain_unregister(
1391                                 &devfreq->transition_notifier_list, nb);
1392                 break;
1393         default:
1394                 ret = -EINVAL;
1395         }
1396
1397         return ret;
1398 }
1399 EXPORT_SYMBOL(devfreq_unregister_notifier);
1400
1401 struct devfreq_notifier_devres {
1402         struct devfreq *devfreq;
1403         struct notifier_block *nb;
1404         unsigned int list;
1405 };
1406
1407 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1408 {
1409         struct devfreq_notifier_devres *this = res;
1410
1411         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1412 }
1413
1414 /**
1415  * devm_devfreq_register_notifier()
1416         - Resource-managed devfreq_register_notifier()
1417  * @dev:        The devfreq user device. (parent of devfreq)
1418  * @devfreq:    The devfreq object.
1419  * @nb:         The notifier block to be unregistered.
1420  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1421  */
1422 int devm_devfreq_register_notifier(struct device *dev,
1423                                 struct devfreq *devfreq,
1424                                 struct notifier_block *nb,
1425                                 unsigned int list)
1426 {
1427         struct devfreq_notifier_devres *ptr;
1428         int ret;
1429
1430         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1431                                 GFP_KERNEL);
1432         if (!ptr)
1433                 return -ENOMEM;
1434
1435         ret = devfreq_register_notifier(devfreq, nb, list);
1436         if (ret) {
1437                 devres_free(ptr);
1438                 return ret;
1439         }
1440
1441         ptr->devfreq = devfreq;
1442         ptr->nb = nb;
1443         ptr->list = list;
1444         devres_add(dev, ptr);
1445
1446         return 0;
1447 }
1448 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1449
1450 /**
1451  * devm_devfreq_unregister_notifier()
1452         - Resource-managed devfreq_unregister_notifier()
1453  * @dev:        The devfreq user device. (parent of devfreq)
1454  * @devfreq:    The devfreq object.
1455  * @nb:         The notifier block to be unregistered.
1456  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1457  */
1458 void devm_devfreq_unregister_notifier(struct device *dev,
1459                                 struct devfreq *devfreq,
1460                                 struct notifier_block *nb,
1461                                 unsigned int list)
1462 {
1463         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1464                                devm_devfreq_dev_match, devfreq));
1465 }
1466 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);
1467
1468 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1469 MODULE_DESCRIPTION("devfreq class support");
1470 MODULE_LICENSE("GPL");