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/export.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_set_freq_table() - Initialize freq_table for the frequency
  90  * @devfreq:    the devfreq instance
  91  */
  92 static void devfreq_set_freq_table(struct devfreq *devfreq)
  93 {
  94         struct devfreq_dev_profile *profile = devfreq->profile;
  95         struct dev_pm_opp *opp;
  96         unsigned long freq;
  97         int i, count;
  98
  99         /* Initialize the freq_table from OPP table */
 100         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 101         if (count <= 0)
 102                 return;
 103
 104         profile->max_state = count;
 105         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 106                                         profile->max_state,
 107                                         sizeof(*profile->freq_table),
 108                                         GFP_KERNEL);
 109         if (!profile->freq_table) {
 110                 profile->max_state = 0;
 111                 return;
 112         }
 113
 114         rcu_read_lock();
 115         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 116                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 117                 if (IS_ERR(opp)) {
 118                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 119                         profile->max_state = 0;
 120                         rcu_read_unlock();
 121                         return;
 122                 }
 123                 profile->freq_table[i] = freq;
 124         }
 125         rcu_read_unlock();
 126 }
 127
 128 /**
 129  * devfreq_update_status() - Update statistics of devfreq behavior
 130  * @devfreq:    the devfreq instance
 131  * @freq:       the update target frequency
 132  */
 133 static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 134 {
 135         int lev, prev_lev, ret = 0;
 136         unsigned long cur_time;
 137
 138         cur_time = jiffies;
 139
 140         /* Immediately exit if previous_freq is not initialized yet. */
 141         if (!devfreq->previous_freq)
 142                 goto out;
 143
 144         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 145         if (prev_lev < 0) {
 146                 ret = prev_lev;
 147                 goto out;
 148         }
 149
 150         devfreq->time_in_state[prev_lev] +=
 151                          cur_time - devfreq->last_stat_updated;
 152
 153         lev = devfreq_get_freq_level(devfreq, freq);
 154         if (lev < 0) {
 155                 ret = lev;
 156                 goto out;
 157         }
 158
 159         if (lev != prev_lev) {
 160                 devfreq->trans_table[(prev_lev *
 161                                 devfreq->profile->max_state) + lev]++;
 162                 devfreq->total_trans++;
 163         }
 164
 165 out:
 166         devfreq->last_stat_updated = cur_time;
 167         return ret;
 168 }
 169
 170 /**
 171  * find_devfreq_governor() - find devfreq governor from name
 172  * @name:       name of the governor
 173  *
 174  * Search the list of devfreq governors and return the matched
 175  * governor's pointer. devfreq_list_lock should be held by the caller.
 176  */
 177 static struct devfreq_governor *find_devfreq_governor(const char *name)
 178 {
 179         struct devfreq_governor *tmp_governor;
 180
 181         if (IS_ERR_OR_NULL(name)) {
 182                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 183                 return ERR_PTR(-EINVAL);
 184         }
 185         WARN(!mutex_is_locked(&devfreq_list_lock),
 186              "devfreq_list_lock must be locked.");
 187
 188         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 189                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 190                         return tmp_governor;
 191         }
 192
 193         return ERR_PTR(-ENODEV);
 194 }
 195
 196 static int devfreq_notify_transition(struct devfreq *devfreq,
 197                 struct devfreq_freqs *freqs, unsigned int state)
 198 {
 199         if (!devfreq)
 200                 return -EINVAL;
 201
 202         switch (state) {
 203         case DEVFREQ_PRECHANGE:
 204                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 205                                 DEVFREQ_PRECHANGE, freqs);
 206                 break;
 207
 208         case DEVFREQ_POSTCHANGE:
 209                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 210                                 DEVFREQ_POSTCHANGE, freqs);
 211                 break;
 212         default:
 213                 return -EINVAL;
 214         }
 215
 216         return 0;
 217 }
 218
 219 /* Load monitoring helper functions for governors use */
 220
 221 /**
 222  * update_devfreq() - Reevaluate the device and configure frequency.
 223  * @devfreq:    the devfreq instance.
 224  *
 225  * Note: Lock devfreq->lock before calling update_devfreq
 226  *       This function is exported for governors.
 227  */
 228 int update_devfreq(struct devfreq *devfreq)
 229 {
 230         struct devfreq_freqs freqs;
 231         unsigned long freq, cur_freq;
 232         int err = 0;
 233         u32 flags = 0;
 234
 235         if (!mutex_is_locked(&devfreq->lock)) {
 236                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 237                 return -EINVAL;
 238         }
 239
 240         if (!devfreq->governor)
 241                 return -EINVAL;
 242
 243         /* Reevaluate the proper frequency */
 244         err = devfreq->governor->get_target_freq(devfreq, &freq);
 245         if (err)
 246                 return err;
 247
 248         /*
 249          * Adjust the frequency with user freq and QoS.
 250          *
 251          * List from the highest priority
 252          * max_freq
 253          * min_freq
 254          */
 255
 256         if (devfreq->min_freq && freq < devfreq->min_freq) {
 257                 freq = devfreq->min_freq;
 258                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 259         }
 260         if (devfreq->max_freq && freq > devfreq->max_freq) {
 261                 freq = devfreq->max_freq;
 262                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 263         }
 264
 265         if (devfreq->profile->get_cur_freq)
 266                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 267         else
 268                 cur_freq = devfreq->previous_freq;
 269
 270         freqs.old = cur_freq;
 271         freqs.new = freq;
 272         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 273
 274         err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 275         if (err) {
 276                 freqs.new = cur_freq;
 277                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 278                 return err;
 279         }
 280
 281         freqs.new = freq;
 282         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 283
 284         if (devfreq->profile->freq_table)
 285                 if (devfreq_update_status(devfreq, freq))
 286                         dev_err(&devfreq->dev,
 287                                 "Couldn't update frequency transition information.\n");
 288
 289         devfreq->previous_freq = freq;
 290         return err;
 291 }
 292 EXPORT_SYMBOL(update_devfreq);
 293
 294 /**
 295  * devfreq_monitor() - Periodically poll devfreq objects.
 296  * @work:       the work struct used to run devfreq_monitor periodically.
 297  *
 298  */
 299 static void devfreq_monitor(struct work_struct *work)
 300 {
 301         int err;
 302         struct devfreq *devfreq = container_of(work,
 303                                         struct devfreq, work.work);
 304
 305         mutex_lock(&devfreq->lock);
 306         err = update_devfreq(devfreq);
 307         if (err)
 308                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 309
 310         queue_delayed_work(devfreq_wq, &devfreq->work,
 311                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 312         mutex_unlock(&devfreq->lock);
 313 }
 314
 315 /**
 316  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 317  * @devfreq:    the devfreq instance.
 318  *
 319  * Helper function for starting devfreq device load monitoing. By
 320  * default delayed work based monitoring is supported. Function
 321  * to be called from governor in response to DEVFREQ_GOV_START
 322  * event when device is added to devfreq framework.
 323  */
 324 void devfreq_monitor_start(struct devfreq *devfreq)
 325 {
 326         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 327         if (devfreq->profile->polling_ms)
 328                 queue_delayed_work(devfreq_wq, &devfreq->work,
 329                         msecs_to_jiffies(devfreq->profile->polling_ms));
 330 }
 331 EXPORT_SYMBOL(devfreq_monitor_start);
 332
 333 /**
 334  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 335  * @devfreq:    the devfreq instance.
 336  *
 337  * Helper function to stop devfreq device load monitoing. Function
 338  * to be called from governor in response to DEVFREQ_GOV_STOP
 339  * event when device is removed from devfreq framework.
 340  */
 341 void devfreq_monitor_stop(struct devfreq *devfreq)
 342 {
 343         cancel_delayed_work_sync(&devfreq->work);
 344 }
 345 EXPORT_SYMBOL(devfreq_monitor_stop);
 346
 347 /**
 348  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 349  * @devfreq:    the devfreq instance.
 350  *
 351  * Helper function to suspend devfreq device load monitoing. Function
 352  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 353  * event or when polling interval is set to zero.
 354  *
 355  * Note: Though this function is same as devfreq_monitor_stop(),
 356  * intentionally kept separate to provide hooks for collecting
 357  * transition statistics.
 358  */
 359 void devfreq_monitor_suspend(struct devfreq *devfreq)
 360 {
 361         mutex_lock(&devfreq->lock);
 362         if (devfreq->stop_polling) {
 363                 mutex_unlock(&devfreq->lock);
 364                 return;
 365         }
 366
 367         devfreq_update_status(devfreq, devfreq->previous_freq);
 368         devfreq->stop_polling = true;
 369         mutex_unlock(&devfreq->lock);
 370         cancel_delayed_work_sync(&devfreq->work);
 371 }
 372 EXPORT_SYMBOL(devfreq_monitor_suspend);
 373
 374 /**
 375  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 376  * @devfreq:    the devfreq instance.
 377  *
 378  * Helper function to resume devfreq device load monitoing. Function
 379  * to be called from governor in response to DEVFREQ_GOV_RESUME
 380  * event or when polling interval is set to non-zero.
 381  */
 382 void devfreq_monitor_resume(struct devfreq *devfreq)
 383 {
 384         unsigned long freq;
 385
 386         mutex_lock(&devfreq->lock);
 387         if (!devfreq->stop_polling)
 388                 goto out;
 389
 390         if (!delayed_work_pending(&devfreq->work) &&
 391                         devfreq->profile->polling_ms)
 392                 queue_delayed_work(devfreq_wq, &devfreq->work,
 393                         msecs_to_jiffies(devfreq->profile->polling_ms));
 394
 395         devfreq->last_stat_updated = jiffies;
 396         devfreq->stop_polling = false;
 397
 398         if (devfreq->profile->get_cur_freq &&
 399                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 400                 devfreq->previous_freq = freq;
 401
 402 out:
 403         mutex_unlock(&devfreq->lock);
 404 }
 405 EXPORT_SYMBOL(devfreq_monitor_resume);
 406
 407 /**
 408  * devfreq_interval_update() - Update device devfreq monitoring interval
 409  * @devfreq:    the devfreq instance.
 410  * @delay:      new polling interval to be set.
 411  *
 412  * Helper function to set new load monitoring polling interval. Function
 413  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 414  */
 415 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 416 {
 417         unsigned int cur_delay = devfreq->profile->polling_ms;
 418         unsigned int new_delay = *delay;
 419
 420         mutex_lock(&devfreq->lock);
 421         devfreq->profile->polling_ms = new_delay;
 422
 423         if (devfreq->stop_polling)
 424                 goto out;
 425
 426         /* if new delay is zero, stop polling */
 427         if (!new_delay) {
 428                 mutex_unlock(&devfreq->lock);
 429                 cancel_delayed_work_sync(&devfreq->work);
 430                 return;
 431         }
 432
 433         /* if current delay is zero, start polling with new delay */
 434         if (!cur_delay) {
 435                 queue_delayed_work(devfreq_wq, &devfreq->work,
 436                         msecs_to_jiffies(devfreq->profile->polling_ms));
 437                 goto out;
 438         }
 439
 440         /* if current delay is greater than new delay, restart polling */
 441         if (cur_delay > new_delay) {
 442                 mutex_unlock(&devfreq->lock);
 443                 cancel_delayed_work_sync(&devfreq->work);
 444                 mutex_lock(&devfreq->lock);
 445                 if (!devfreq->stop_polling)
 446                         queue_delayed_work(devfreq_wq, &devfreq->work,
 447                               msecs_to_jiffies(devfreq->profile->polling_ms));
 448         }
 449 out:
 450         mutex_unlock(&devfreq->lock);
 451 }
 452 EXPORT_SYMBOL(devfreq_interval_update);
 453
 454 /**
 455  * devfreq_notifier_call() - Notify that the device frequency requirements
 456  *                         has been changed out of devfreq framework.
 457  * @nb:         the notifier_block (supposed to be devfreq->nb)
 458  * @type:       not used
 459  * @devp:       not used
 460  *
 461  * Called by a notifier that uses devfreq->nb.
 462  */
 463 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 464                                  void *devp)
 465 {
 466         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 467         int ret;
 468
 469         mutex_lock(&devfreq->lock);
 470         ret = update_devfreq(devfreq);
 471         mutex_unlock(&devfreq->lock);
 472
 473         return ret;
 474 }
 475
 476 /**
 477  * _remove_devfreq() - Remove devfreq from the list and release its resources.
 478  * @devfreq:    the devfreq struct
 479  */
 480 static void _remove_devfreq(struct devfreq *devfreq)
 481 {
 482         mutex_lock(&devfreq_list_lock);
 483         if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
 484                 mutex_unlock(&devfreq_list_lock);
 485                 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
 486                 return;
 487         }
 488         list_del(&devfreq->node);
 489         mutex_unlock(&devfreq_list_lock);
 490
 491         if (devfreq->governor)
 492                 devfreq->governor->event_handler(devfreq,
 493                                                  DEVFREQ_GOV_STOP, NULL);
 494
 495         if (devfreq->profile->exit)
 496                 devfreq->profile->exit(devfreq->dev.parent);
 497
 498         mutex_destroy(&devfreq->lock);
 499         kfree(devfreq);
 500 }
 501
 502 /**
 503  * devfreq_dev_release() - Callback for struct device to release the device.
 504  * @dev:        the devfreq device
 505  *
 506  * This calls _remove_devfreq() if _remove_devfreq() is not called.
 507  */
 508 static void devfreq_dev_release(struct device *dev)
 509 {
 510         struct devfreq *devfreq = to_devfreq(dev);
 511
 512         _remove_devfreq(devfreq);
 513 }
 514
 515 /**
 516  * devfreq_add_device() - Add devfreq feature to the device
 517  * @dev:        the device to add devfreq feature.
 518  * @profile:    device-specific profile to run devfreq.
 519  * @governor_name:      name of the policy to choose frequency.
 520  * @data:       private data for the governor. The devfreq framework does not
 521  *              touch this value.
 522  */
 523 struct devfreq *devfreq_add_device(struct device *dev,
 524                                    struct devfreq_dev_profile *profile,
 525                                    const char *governor_name,
 526                                    void *data)
 527 {
 528         struct devfreq *devfreq;
 529         struct devfreq_governor *governor;
 530         int err = 0;
 531
 532         if (!dev || !profile || !governor_name) {
 533                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 534                 return ERR_PTR(-EINVAL);
 535         }
 536
 537         mutex_lock(&devfreq_list_lock);
 538         devfreq = find_device_devfreq(dev);
 539         mutex_unlock(&devfreq_list_lock);
 540         if (!IS_ERR(devfreq)) {
 541                 dev_err(dev, "%s: Unable to create devfreq for the device.\n",
 542                         __func__);
 543                 err = -EINVAL;
 544                 goto err_out;
 545         }
 546
 547         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 548         if (!devfreq) {
 549                 err = -ENOMEM;
 550                 goto err_out;
 551         }
 552
 553         mutex_init(&devfreq->lock);
 554         mutex_lock(&devfreq->lock);
 555         devfreq->dev.parent = dev;
 556         devfreq->dev.class = devfreq_class;
 557         devfreq->dev.release = devfreq_dev_release;
 558         devfreq->profile = profile;
 559         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 560         devfreq->previous_freq = profile->initial_freq;
 561         devfreq->last_status.current_frequency = profile->initial_freq;
 562         devfreq->data = data;
 563         devfreq->nb.notifier_call = devfreq_notifier_call;
 564
 565         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 566                 mutex_unlock(&devfreq->lock);
 567                 devfreq_set_freq_table(devfreq);
 568                 mutex_lock(&devfreq->lock);
 569         }
 570
 571         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 572         err = device_register(&devfreq->dev);
 573         if (err) {
 574                 mutex_unlock(&devfreq->lock);
 575                 goto err_out;
 576         }
 577
 578         devfreq->trans_table =  devm_kzalloc(&devfreq->dev,
 579                                                 sizeof(unsigned int) *
 580                                                 devfreq->profile->max_state *
 581                                                 devfreq->profile->max_state,
 582                                                 GFP_KERNEL);
 583         devfreq->time_in_state = devm_kzalloc(&devfreq->dev,
 584                                                 sizeof(unsigned long) *
 585                                                 devfreq->profile->max_state,
 586                                                 GFP_KERNEL);
 587         devfreq->last_stat_updated = jiffies;
 588
 589         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 590
 591         mutex_unlock(&devfreq->lock);
 592
 593         mutex_lock(&devfreq_list_lock);
 594         list_add(&devfreq->node, &devfreq_list);
 595
 596         governor = find_devfreq_governor(devfreq->governor_name);
 597         if (IS_ERR(governor)) {
 598                 dev_err(dev, "%s: Unable to find governor for the device\n",
 599                         __func__);
 600                 err = PTR_ERR(governor);
 601                 goto err_init;
 602         }
 603
 604         devfreq->governor = governor;
 605         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 606                                                 NULL);
 607         if (err) {
 608                 dev_err(dev, "%s: Unable to start governor for the device\n",
 609                         __func__);
 610                 goto err_init;
 611         }
 612         mutex_unlock(&devfreq_list_lock);
 613
 614         return devfreq;
 615
 616 err_init:
 617         list_del(&devfreq->node);
 618         mutex_unlock(&devfreq_list_lock);
 619
 620         device_unregister(&devfreq->dev);
 621 err_out:
 622         return ERR_PTR(err);
 623 }
 624 EXPORT_SYMBOL(devfreq_add_device);
 625
 626 /**
 627  * devfreq_remove_device() - Remove devfreq feature from a device.
 628  * @devfreq:    the devfreq instance to be removed
 629  *
 630  * The opposite of devfreq_add_device().
 631  */
 632 int devfreq_remove_device(struct devfreq *devfreq)
 633 {
 634         if (!devfreq)
 635                 return -EINVAL;
 636
 637         device_unregister(&devfreq->dev);
 638
 639         return 0;
 640 }
 641 EXPORT_SYMBOL(devfreq_remove_device);
 642
 643 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 644 {
 645         struct devfreq **r = res;
 646
 647         if (WARN_ON(!r || !*r))
 648                 return 0;
 649
 650         return *r == data;
 651 }
 652
 653 static void devm_devfreq_dev_release(struct device *dev, void *res)
 654 {
 655         devfreq_remove_device(*(struct devfreq **)res);
 656 }
 657
 658 /**
 659  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 660  * @dev:        the device to add devfreq feature.
 661  * @profile:    device-specific profile to run devfreq.
 662  * @governor_name:      name of the policy to choose frequency.
 663  * @data:       private data for the governor. The devfreq framework does not
 664  *              touch this value.
 665  *
 666  * This function manages automatically the memory of devfreq device using device
 667  * resource management and simplify the free operation for memory of devfreq
 668  * device.
 669  */
 670 struct devfreq *devm_devfreq_add_device(struct device *dev,
 671                                         struct devfreq_dev_profile *profile,
 672                                         const char *governor_name,
 673                                         void *data)
 674 {
 675         struct devfreq **ptr, *devfreq;
 676
 677         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 678         if (!ptr)
 679                 return ERR_PTR(-ENOMEM);
 680
 681         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 682         if (IS_ERR(devfreq)) {
 683                 devres_free(ptr);
 684                 return ERR_PTR(-ENOMEM);
 685         }
 686
 687         *ptr = devfreq;
 688         devres_add(dev, ptr);
 689
 690         return devfreq;
 691 }
 692 EXPORT_SYMBOL(devm_devfreq_add_device);
 693
 694 #ifdef CONFIG_OF
 695 /*
 696  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 697  * @dev - instance to the given device
 698  * @index - index into list of devfreq
 699  *
 700  * return the instance of devfreq device
 701  */
 702 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 703 {
 704         struct device_node *node;
 705         struct devfreq *devfreq;
 706
 707         if (!dev)
 708                 return ERR_PTR(-EINVAL);
 709
 710         if (!dev->of_node)
 711                 return ERR_PTR(-EINVAL);
 712
 713         node = of_parse_phandle(dev->of_node, "devfreq", index);
 714         if (!node)
 715                 return ERR_PTR(-ENODEV);
 716
 717         mutex_lock(&devfreq_list_lock);
 718         list_for_each_entry(devfreq, &devfreq_list, node) {
 719                 if (devfreq->dev.parent
 720                         && devfreq->dev.parent->of_node == node) {
 721                         mutex_unlock(&devfreq_list_lock);
 722                         of_node_put(node);
 723                         return devfreq;
 724                 }
 725         }
 726         mutex_unlock(&devfreq_list_lock);
 727         of_node_put(node);
 728
 729         return ERR_PTR(-EPROBE_DEFER);
 730 }
 731 #else
 732 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 733 {
 734         return ERR_PTR(-ENODEV);
 735 }
 736 #endif /* CONFIG_OF */
 737 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 738
 739 /**
 740  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 741  * @dev:        the device to add devfreq feature.
 742  * @devfreq:    the devfreq instance to be removed
 743  */
 744 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 745 {
 746         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 747                                devm_devfreq_dev_match, devfreq));
 748 }
 749 EXPORT_SYMBOL(devm_devfreq_remove_device);
 750
 751 /**
 752  * devfreq_suspend_device() - Suspend devfreq of a device.
 753  * @devfreq: the devfreq instance to be suspended
 754  *
 755  * This function is intended to be called by the pm callbacks
 756  * (e.g., runtime_suspend, suspend) of the device driver that
 757  * holds the devfreq.
 758  */
 759 int devfreq_suspend_device(struct devfreq *devfreq)
 760 {
 761         if (!devfreq)
 762                 return -EINVAL;
 763
 764         if (!devfreq->governor)
 765                 return 0;
 766
 767         return devfreq->governor->event_handler(devfreq,
 768                                 DEVFREQ_GOV_SUSPEND, NULL);
 769 }
 770 EXPORT_SYMBOL(devfreq_suspend_device);
 771
 772 /**
 773  * devfreq_resume_device() - Resume devfreq of a device.
 774  * @devfreq: the devfreq instance to be resumed
 775  *
 776  * This function is intended to be called by the pm callbacks
 777  * (e.g., runtime_resume, resume) of the device driver that
 778  * holds the devfreq.
 779  */
 780 int devfreq_resume_device(struct devfreq *devfreq)
 781 {
 782         if (!devfreq)
 783                 return -EINVAL;
 784
 785         if (!devfreq->governor)
 786                 return 0;
 787
 788         return devfreq->governor->event_handler(devfreq,
 789                                 DEVFREQ_GOV_RESUME, NULL);
 790 }
 791 EXPORT_SYMBOL(devfreq_resume_device);
 792
 793 /**
 794  * devfreq_add_governor() - Add devfreq governor
 795  * @governor:   the devfreq governor to be added
 796  */
 797 int devfreq_add_governor(struct devfreq_governor *governor)
 798 {
 799         struct devfreq_governor *g;
 800         struct devfreq *devfreq;
 801         int err = 0;
 802
 803         if (!governor) {
 804                 pr_err("%s: Invalid parameters.\n", __func__);
 805                 return -EINVAL;
 806         }
 807
 808         mutex_lock(&devfreq_list_lock);
 809         g = find_devfreq_governor(governor->name);
 810         if (!IS_ERR(g)) {
 811                 pr_err("%s: governor %s already registered\n", __func__,
 812                        g->name);
 813                 err = -EINVAL;
 814                 goto err_out;
 815         }
 816
 817         list_add(&governor->node, &devfreq_governor_list);
 818
 819         list_for_each_entry(devfreq, &devfreq_list, node) {
 820                 int ret = 0;
 821                 struct device *dev = devfreq->dev.parent;
 822
 823                 if (!strncmp(devfreq->governor_name, governor->name,
 824                              DEVFREQ_NAME_LEN)) {
 825                         /* The following should never occur */
 826                         if (devfreq->governor) {
 827                                 dev_warn(dev,
 828                                          "%s: Governor %s already present\n",
 829                                          __func__, devfreq->governor->name);
 830                                 ret = devfreq->governor->event_handler(devfreq,
 831                                                         DEVFREQ_GOV_STOP, NULL);
 832                                 if (ret) {
 833                                         dev_warn(dev,
 834                                                  "%s: Governor %s stop = %d\n",
 835                                                  __func__,
 836                                                  devfreq->governor->name, ret);
 837                                 }
 838                                 /* Fall through */
 839                         }
 840                         devfreq->governor = governor;
 841                         ret = devfreq->governor->event_handler(devfreq,
 842                                                 DEVFREQ_GOV_START, NULL);
 843                         if (ret) {
 844                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 845                                          __func__, devfreq->governor->name,
 846                                          ret);
 847                         }
 848                 }
 849         }
 850
 851 err_out:
 852         mutex_unlock(&devfreq_list_lock);
 853
 854         return err;
 855 }
 856 EXPORT_SYMBOL(devfreq_add_governor);
 857
 858 /**
 859  * devfreq_remove_governor() - Remove devfreq feature from a device.
 860  * @governor:   the devfreq governor to be removed
 861  */
 862 int devfreq_remove_governor(struct devfreq_governor *governor)
 863 {
 864         struct devfreq_governor *g;
 865         struct devfreq *devfreq;
 866         int err = 0;
 867
 868         if (!governor) {
 869                 pr_err("%s: Invalid parameters.\n", __func__);
 870                 return -EINVAL;
 871         }
 872
 873         mutex_lock(&devfreq_list_lock);
 874         g = find_devfreq_governor(governor->name);
 875         if (IS_ERR(g)) {
 876                 pr_err("%s: governor %s not registered\n", __func__,
 877                        governor->name);
 878                 err = PTR_ERR(g);
 879                 goto err_out;
 880         }
 881         list_for_each_entry(devfreq, &devfreq_list, node) {
 882                 int ret;
 883                 struct device *dev = devfreq->dev.parent;
 884
 885                 if (!strncmp(devfreq->governor_name, governor->name,
 886                              DEVFREQ_NAME_LEN)) {
 887                         /* we should have a devfreq governor! */
 888                         if (!devfreq->governor) {
 889                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 890                                          __func__, governor->name);
 891                                 continue;
 892                                 /* Fall through */
 893                         }
 894                         ret = devfreq->governor->event_handler(devfreq,
 895                                                 DEVFREQ_GOV_STOP, NULL);
 896                         if (ret) {
 897                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 898                                          __func__, devfreq->governor->name,
 899                                          ret);
 900                         }
 901                         devfreq->governor = NULL;
 902                 }
 903         }
 904
 905         list_del(&governor->node);
 906 err_out:
 907         mutex_unlock(&devfreq_list_lock);
 908
 909         return err;
 910 }
 911 EXPORT_SYMBOL(devfreq_remove_governor);
 912
 913 static ssize_t governor_show(struct device *dev,
 914                              struct device_attribute *attr, char *buf)
 915 {
 916         if (!to_devfreq(dev)->governor)
 917                 return -EINVAL;
 918
 919         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 920 }
 921
 922 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 923                               const char *buf, size_t count)
 924 {
 925         struct devfreq *df = to_devfreq(dev);
 926         int ret;
 927         char str_governor[DEVFREQ_NAME_LEN + 1];
 928         struct devfreq_governor *governor;
 929
 930         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 931         if (ret != 1)
 932                 return -EINVAL;
 933
 934         mutex_lock(&devfreq_list_lock);
 935         governor = find_devfreq_governor(str_governor);
 936         if (IS_ERR(governor)) {
 937                 ret = PTR_ERR(governor);
 938                 goto out;
 939         }
 940         if (df->governor == governor) {
 941                 ret = 0;
 942                 goto out;
 943         }
 944
 945         if (df->governor) {
 946                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
 947                 if (ret) {
 948                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
 949                                  __func__, df->governor->name, ret);
 950                         goto out;
 951                 }
 952         }
 953         df->governor = governor;
 954         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
 955         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
 956         if (ret)
 957                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
 958                          __func__, df->governor->name, ret);
 959 out:
 960         mutex_unlock(&devfreq_list_lock);
 961
 962         if (!ret)
 963                 ret = count;
 964         return ret;
 965 }
 966 static DEVICE_ATTR_RW(governor);
 967
 968 static ssize_t available_governors_show(struct device *d,
 969                                         struct device_attribute *attr,
 970                                         char *buf)
 971 {
 972         struct devfreq_governor *tmp_governor;
 973         ssize_t count = 0;
 974
 975         mutex_lock(&devfreq_list_lock);
 976         list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
 977                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
 978                                    "%s ", tmp_governor->name);
 979         mutex_unlock(&devfreq_list_lock);
 980
 981         /* Truncate the trailing space */
 982         if (count)
 983                 count--;
 984
 985         count += sprintf(&buf[count], "\n");
 986
 987         return count;
 988 }
 989 static DEVICE_ATTR_RO(available_governors);
 990
 991 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
 992                              char *buf)
 993 {
 994         unsigned long freq;
 995         struct devfreq *devfreq = to_devfreq(dev);
 996
 997         if (devfreq->profile->get_cur_freq &&
 998                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 999                 return sprintf(buf, "%lu\n", freq);
1000
1001         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1002 }
1003 static DEVICE_ATTR_RO(cur_freq);
1004
1005 static ssize_t target_freq_show(struct device *dev,
1006                                 struct device_attribute *attr, char *buf)
1007 {
1008         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1009 }
1010 static DEVICE_ATTR_RO(target_freq);
1011
1012 static ssize_t polling_interval_show(struct device *dev,
1013                                      struct device_attribute *attr, char *buf)
1014 {
1015         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1016 }
1017
1018 static ssize_t polling_interval_store(struct device *dev,
1019                                       struct device_attribute *attr,
1020                                       const char *buf, size_t count)
1021 {
1022         struct devfreq *df = to_devfreq(dev);
1023         unsigned int value;
1024         int ret;
1025
1026         if (!df->governor)
1027                 return -EINVAL;
1028
1029         ret = sscanf(buf, "%u", &value);
1030         if (ret != 1)
1031                 return -EINVAL;
1032
1033         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1034         ret = count;
1035
1036         return ret;
1037 }
1038 static DEVICE_ATTR_RW(polling_interval);
1039
1040 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1041                               const char *buf, size_t count)
1042 {
1043         struct devfreq *df = to_devfreq(dev);
1044         unsigned long value;
1045         int ret;
1046         unsigned long max;
1047
1048         ret = sscanf(buf, "%lu", &value);
1049         if (ret != 1)
1050                 return -EINVAL;
1051
1052         mutex_lock(&df->lock);
1053         max = df->max_freq;
1054         if (value && max && value > max) {
1055                 ret = -EINVAL;
1056                 goto unlock;
1057         }
1058
1059         df->min_freq = value;
1060         update_devfreq(df);
1061         ret = count;
1062 unlock:
1063         mutex_unlock(&df->lock);
1064         return ret;
1065 }
1066
1067 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1068                               const char *buf, size_t count)
1069 {
1070         struct devfreq *df = to_devfreq(dev);
1071         unsigned long value;
1072         int ret;
1073         unsigned long min;
1074
1075         ret = sscanf(buf, "%lu", &value);
1076         if (ret != 1)
1077                 return -EINVAL;
1078
1079         mutex_lock(&df->lock);
1080         min = df->min_freq;
1081         if (value && min && value < min) {
1082                 ret = -EINVAL;
1083                 goto unlock;
1084         }
1085
1086         df->max_freq = value;
1087         update_devfreq(df);
1088         ret = count;
1089 unlock:
1090         mutex_unlock(&df->lock);
1091         return ret;
1092 }
1093
1094 #define show_one(name)                                          \
1095 static ssize_t name##_show                                      \
1096 (struct device *dev, struct device_attribute *attr, char *buf)  \
1097 {                                                               \
1098         return sprintf(buf, "%lu\n", to_devfreq(dev)->name);    \
1099 }
1100 show_one(min_freq);
1101 show_one(max_freq);
1102
1103 static DEVICE_ATTR_RW(min_freq);
1104 static DEVICE_ATTR_RW(max_freq);
1105
1106 static ssize_t available_frequencies_show(struct device *d,
1107                                           struct device_attribute *attr,
1108                                           char *buf)
1109 {
1110         struct devfreq *df = to_devfreq(d);
1111         struct device *dev = df->dev.parent;
1112         struct dev_pm_opp *opp;
1113         ssize_t count = 0;
1114         unsigned long freq = 0;
1115
1116         rcu_read_lock();
1117         do {
1118                 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1119                 if (IS_ERR(opp))
1120                         break;
1121
1122                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1123                                    "%lu ", freq);
1124                 freq++;
1125         } while (1);
1126         rcu_read_unlock();
1127
1128         /* Truncate the trailing space */
1129         if (count)
1130                 count--;
1131
1132         count += sprintf(&buf[count], "\n");
1133
1134         return count;
1135 }
1136 static DEVICE_ATTR_RO(available_frequencies);
1137
1138 static ssize_t trans_stat_show(struct device *dev,
1139                                struct device_attribute *attr, char *buf)
1140 {
1141         struct devfreq *devfreq = to_devfreq(dev);
1142         ssize_t len;
1143         int i, j;
1144         unsigned int max_state = devfreq->profile->max_state;
1145
1146         if (!devfreq->stop_polling &&
1147                         devfreq_update_status(devfreq, devfreq->previous_freq))
1148                 return 0;
1149         if (max_state == 0)
1150                 return sprintf(buf, "Not Supported.\n");
1151
1152         len = sprintf(buf, "     From  :   To\n");
1153         len += sprintf(buf + len, "           :");
1154         for (i = 0; i < max_state; i++)
1155                 len += sprintf(buf + len, "%10lu",
1156                                 devfreq->profile->freq_table[i]);
1157
1158         len += sprintf(buf + len, "   time(ms)\n");
1159
1160         for (i = 0; i < max_state; i++) {
1161                 if (devfreq->profile->freq_table[i]
1162                                         == devfreq->previous_freq) {
1163                         len += sprintf(buf + len, "*");
1164                 } else {
1165                         len += sprintf(buf + len, " ");
1166                 }
1167                 len += sprintf(buf + len, "%10lu:",
1168                                 devfreq->profile->freq_table[i]);
1169                 for (j = 0; j < max_state; j++)
1170                         len += sprintf(buf + len, "%10u",
1171                                 devfreq->trans_table[(i * max_state) + j]);
1172                 len += sprintf(buf + len, "%10u\n",
1173                         jiffies_to_msecs(devfreq->time_in_state[i]));
1174         }
1175
1176         len += sprintf(buf + len, "Total transition : %u\n",
1177                                         devfreq->total_trans);
1178         return len;
1179 }
1180 static DEVICE_ATTR_RO(trans_stat);
1181
1182 static struct attribute *devfreq_attrs[] = {
1183         &dev_attr_governor.attr,
1184         &dev_attr_available_governors.attr,
1185         &dev_attr_cur_freq.attr,
1186         &dev_attr_available_frequencies.attr,
1187         &dev_attr_target_freq.attr,
1188         &dev_attr_polling_interval.attr,
1189         &dev_attr_min_freq.attr,
1190         &dev_attr_max_freq.attr,
1191         &dev_attr_trans_stat.attr,
1192         NULL,
1193 };
1194 ATTRIBUTE_GROUPS(devfreq);
1195
1196 static int __init devfreq_init(void)
1197 {
1198         devfreq_class = class_create(THIS_MODULE, "devfreq");
1199         if (IS_ERR(devfreq_class)) {
1200                 pr_err("%s: couldn't create class\n", __FILE__);
1201                 return PTR_ERR(devfreq_class);
1202         }
1203
1204         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1205         if (!devfreq_wq) {
1206                 class_destroy(devfreq_class);
1207                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1208                 return -ENOMEM;
1209         }
1210         devfreq_class->dev_groups = devfreq_groups;
1211
1212         return 0;
1213 }
1214 subsys_initcall(devfreq_init);
1215
1216 /*
1217  * The followings are helper functions for devfreq user device drivers with
1218  * OPP framework.
1219  */
1220
1221 /**
1222  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1223  *                           freq value given to target callback.
1224  * @dev:        The devfreq user device. (parent of devfreq)
1225  * @freq:       The frequency given to target function
1226  * @flags:      Flags handed from devfreq framework.
1227  *
1228  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1229  * protected pointer. The reason for the same is that the opp pointer which is
1230  * returned will remain valid for use with opp_get_{voltage, freq} only while
1231  * under the locked area. The pointer returned must be used prior to unlocking
1232  * with rcu_read_unlock() to maintain the integrity of the pointer.
1233  */
1234 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1235                                            unsigned long *freq,
1236                                            u32 flags)
1237 {
1238         struct dev_pm_opp *opp;
1239
1240         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1241                 /* The freq is an upper bound. opp should be lower */
1242                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1243
1244                 /* If not available, use the closest opp */
1245                 if (opp == ERR_PTR(-ERANGE))
1246                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1247         } else {
1248                 /* The freq is an lower bound. opp should be higher */
1249                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1250
1251                 /* If not available, use the closest opp */
1252                 if (opp == ERR_PTR(-ERANGE))
1253                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1254         }
1255
1256         return opp;
1257 }
1258 EXPORT_SYMBOL(devfreq_recommended_opp);
1259
1260 /**
1261  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1262  *                                 for any changes in the OPP availability
1263  *                                 changes
1264  * @dev:        The devfreq user device. (parent of devfreq)
1265  * @devfreq:    The devfreq object.
1266  */
1267 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1268 {
1269         struct srcu_notifier_head *nh;
1270         int ret = 0;
1271
1272         rcu_read_lock();
1273         nh = dev_pm_opp_get_notifier(dev);
1274         if (IS_ERR(nh))
1275                 ret = PTR_ERR(nh);
1276         rcu_read_unlock();
1277         if (!ret)
1278                 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1279
1280         return ret;
1281 }
1282 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1283
1284 /**
1285  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1286  *                                   notified for any changes in the OPP
1287  *                                   availability changes anymore.
1288  * @dev:        The devfreq user device. (parent of devfreq)
1289  * @devfreq:    The devfreq object.
1290  *
1291  * At exit() callback of devfreq_dev_profile, this must be included if
1292  * devfreq_recommended_opp is used.
1293  */
1294 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1295 {
1296         struct srcu_notifier_head *nh;
1297         int ret = 0;
1298
1299         rcu_read_lock();
1300         nh = dev_pm_opp_get_notifier(dev);
1301         if (IS_ERR(nh))
1302                 ret = PTR_ERR(nh);
1303         rcu_read_unlock();
1304         if (!ret)
1305                 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1306
1307         return ret;
1308 }
1309 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1310
1311 static void devm_devfreq_opp_release(struct device *dev, void *res)
1312 {
1313         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1314 }
1315
1316 /**
1317  * devm_ devfreq_register_opp_notifier()
1318  *              - Resource-managed devfreq_register_opp_notifier()
1319  * @dev:        The devfreq user device. (parent of devfreq)
1320  * @devfreq:    The devfreq object.
1321  */
1322 int devm_devfreq_register_opp_notifier(struct device *dev,
1323                                        struct devfreq *devfreq)
1324 {
1325         struct devfreq **ptr;
1326         int ret;
1327
1328         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1329         if (!ptr)
1330                 return -ENOMEM;
1331
1332         ret = devfreq_register_opp_notifier(dev, devfreq);
1333         if (ret) {
1334                 devres_free(ptr);
1335                 return ret;
1336         }
1337
1338         *ptr = devfreq;
1339         devres_add(dev, ptr);
1340
1341         return 0;
1342 }
1343 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1344
1345 /**
1346  * devm_devfreq_unregister_opp_notifier()
1347  *              - Resource-managed devfreq_unregister_opp_notifier()
1348  * @dev:        The devfreq user device. (parent of devfreq)
1349  * @devfreq:    The devfreq object.
1350  */
1351 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1352                                          struct devfreq *devfreq)
1353 {
1354         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1355                                devm_devfreq_dev_match, devfreq));
1356 }
1357 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1358
1359 /**
1360  * devfreq_register_notifier() - Register a driver with devfreq
1361  * @devfreq:    The devfreq object.
1362  * @nb:         The notifier block to register.
1363  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1364  */
1365 int devfreq_register_notifier(struct devfreq *devfreq,
1366                                 struct notifier_block *nb,
1367                                 unsigned int list)
1368 {
1369         int ret = 0;
1370
1371         if (!devfreq)
1372                 return -EINVAL;
1373
1374         switch (list) {
1375         case DEVFREQ_TRANSITION_NOTIFIER:
1376                 ret = srcu_notifier_chain_register(
1377                                 &devfreq->transition_notifier_list, nb);
1378                 break;
1379         default:
1380                 ret = -EINVAL;
1381         }
1382
1383         return ret;
1384 }
1385 EXPORT_SYMBOL(devfreq_register_notifier);
1386
1387 /*
1388  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1389  * @devfreq:    The devfreq object.
1390  * @nb:         The notifier block to be unregistered.
1391  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1392  */
1393 int devfreq_unregister_notifier(struct devfreq *devfreq,
1394                                 struct notifier_block *nb,
1395                                 unsigned int list)
1396 {
1397         int ret = 0;
1398
1399         if (!devfreq)
1400                 return -EINVAL;
1401
1402         switch (list) {
1403         case DEVFREQ_TRANSITION_NOTIFIER:
1404                 ret = srcu_notifier_chain_unregister(
1405                                 &devfreq->transition_notifier_list, nb);
1406                 break;
1407         default:
1408                 ret = -EINVAL;
1409         }
1410
1411         return ret;
1412 }
1413 EXPORT_SYMBOL(devfreq_unregister_notifier);
1414
1415 struct devfreq_notifier_devres {
1416         struct devfreq *devfreq;
1417         struct notifier_block *nb;
1418         unsigned int list;
1419 };
1420
1421 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1422 {
1423         struct devfreq_notifier_devres *this = res;
1424
1425         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1426 }
1427
1428 /**
1429  * devm_devfreq_register_notifier()
1430         - Resource-managed devfreq_register_notifier()
1431  * @dev:        The devfreq user device. (parent of devfreq)
1432  * @devfreq:    The devfreq object.
1433  * @nb:         The notifier block to be unregistered.
1434  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1435  */
1436 int devm_devfreq_register_notifier(struct device *dev,
1437                                 struct devfreq *devfreq,
1438                                 struct notifier_block *nb,
1439                                 unsigned int list)
1440 {
1441         struct devfreq_notifier_devres *ptr;
1442         int ret;
1443
1444         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1445                                 GFP_KERNEL);
1446         if (!ptr)
1447                 return -ENOMEM;
1448
1449         ret = devfreq_register_notifier(devfreq, nb, list);
1450         if (ret) {
1451                 devres_free(ptr);
1452                 return ret;
1453         }
1454
1455         ptr->devfreq = devfreq;
1456         ptr->nb = nb;
1457         ptr->list = list;
1458         devres_add(dev, ptr);
1459
1460         return 0;
1461 }
1462 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1463
1464 /**
1465  * devm_devfreq_unregister_notifier()
1466         - Resource-managed devfreq_unregister_notifier()
1467  * @dev:        The devfreq user device. (parent of devfreq)
1468  * @devfreq:    The devfreq object.
1469  * @nb:         The notifier block to be unregistered.
1470  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1471  */
1472 void devm_devfreq_unregister_notifier(struct device *dev,
1473                                 struct devfreq *devfreq,
1474                                 struct notifier_block *nb,
1475                                 unsigned int list)
1476 {
1477         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1478                                devm_devfreq_dev_match, devfreq));
1479 }
1480 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);