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 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 EXPORT_SYMBOL(devfreq_update_status);
 170
 171 /**
 172  * find_devfreq_governor() - find devfreq governor from name
 173  * @name:       name of the governor
 174  *
 175  * Search the list of devfreq governors and return the matched
 176  * governor's pointer. devfreq_list_lock should be held by the caller.
 177  */
 178 static struct devfreq_governor *find_devfreq_governor(const char *name)
 179 {
 180         struct devfreq_governor *tmp_governor;
 181
 182         if (IS_ERR_OR_NULL(name)) {
 183                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 184                 return ERR_PTR(-EINVAL);
 185         }
 186         WARN(!mutex_is_locked(&devfreq_list_lock),
 187              "devfreq_list_lock must be locked.");
 188
 189         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 190                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 191                         return tmp_governor;
 192         }
 193
 194         return ERR_PTR(-ENODEV);
 195 }
 196
 197 static int devfreq_notify_transition(struct devfreq *devfreq,
 198                 struct devfreq_freqs *freqs, unsigned int state)
 199 {
 200         if (!devfreq)
 201                 return -EINVAL;
 202
 203         switch (state) {
 204         case DEVFREQ_PRECHANGE:
 205                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 206                                 DEVFREQ_PRECHANGE, freqs);
 207                 break;
 208
 209         case DEVFREQ_POSTCHANGE:
 210                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 211                                 DEVFREQ_POSTCHANGE, freqs);
 212                 break;
 213         default:
 214                 return -EINVAL;
 215         }
 216
 217         return 0;
 218 }
 219
 220 /* Load monitoring helper functions for governors use */
 221
 222 /**
 223  * update_devfreq() - Reevaluate the device and configure frequency.
 224  * @devfreq:    the devfreq instance.
 225  *
 226  * Note: Lock devfreq->lock before calling update_devfreq
 227  *       This function is exported for governors.
 228  */
 229 int update_devfreq(struct devfreq *devfreq)
 230 {
 231         struct devfreq_freqs freqs;
 232         unsigned long freq, cur_freq;
 233         int err = 0;
 234         u32 flags = 0;
 235
 236         if (!mutex_is_locked(&devfreq->lock)) {
 237                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 238                 return -EINVAL;
 239         }
 240
 241         if (!devfreq->governor)
 242                 return -EINVAL;
 243
 244         /* Reevaluate the proper frequency */
 245         err = devfreq->governor->get_target_freq(devfreq, &freq);
 246         if (err)
 247                 return err;
 248
 249         /*
 250          * Adjust the frequency with user freq and QoS.
 251          *
 252          * List from the highest priority
 253          * max_freq
 254          * min_freq
 255          */
 256
 257         if (devfreq->min_freq && freq < devfreq->min_freq) {
 258                 freq = devfreq->min_freq;
 259                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 260         }
 261         if (devfreq->max_freq && freq > devfreq->max_freq) {
 262                 freq = devfreq->max_freq;
 263                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 264         }
 265
 266         if (devfreq->profile->get_cur_freq)
 267                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 268         else
 269                 cur_freq = devfreq->previous_freq;
 270
 271         freqs.old = cur_freq;
 272         freqs.new = freq;
 273         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 274
 275         err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 276         if (err) {
 277                 freqs.new = cur_freq;
 278                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 279                 return err;
 280         }
 281
 282         freqs.new = freq;
 283         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 284
 285         if (devfreq->profile->freq_table)
 286                 if (devfreq_update_status(devfreq, freq))
 287                         dev_err(&devfreq->dev,
 288                                 "Couldn't update frequency transition information.\n");
 289
 290         devfreq->previous_freq = freq;
 291         return err;
 292 }
 293 EXPORT_SYMBOL(update_devfreq);
 294
 295 /**
 296  * devfreq_monitor() - Periodically poll devfreq objects.
 297  * @work:       the work struct used to run devfreq_monitor periodically.
 298  *
 299  */
 300 static void devfreq_monitor(struct work_struct *work)
 301 {
 302         int err;
 303         struct devfreq *devfreq = container_of(work,
 304                                         struct devfreq, work.work);
 305
 306         mutex_lock(&devfreq->lock);
 307         err = update_devfreq(devfreq);
 308         if (err)
 309                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 310
 311         queue_delayed_work(devfreq_wq, &devfreq->work,
 312                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 313         mutex_unlock(&devfreq->lock);
 314 }
 315
 316 /**
 317  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 318  * @devfreq:    the devfreq instance.
 319  *
 320  * Helper function for starting devfreq device load monitoing. By
 321  * default delayed work based monitoring is supported. Function
 322  * to be called from governor in response to DEVFREQ_GOV_START
 323  * event when device is added to devfreq framework.
 324  */
 325 void devfreq_monitor_start(struct devfreq *devfreq)
 326 {
 327         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 328         if (devfreq->profile->polling_ms)
 329                 queue_delayed_work(devfreq_wq, &devfreq->work,
 330                         msecs_to_jiffies(devfreq->profile->polling_ms));
 331 }
 332 EXPORT_SYMBOL(devfreq_monitor_start);
 333
 334 /**
 335  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 336  * @devfreq:    the devfreq instance.
 337  *
 338  * Helper function to stop devfreq device load monitoing. Function
 339  * to be called from governor in response to DEVFREQ_GOV_STOP
 340  * event when device is removed from devfreq framework.
 341  */
 342 void devfreq_monitor_stop(struct devfreq *devfreq)
 343 {
 344         cancel_delayed_work_sync(&devfreq->work);
 345 }
 346 EXPORT_SYMBOL(devfreq_monitor_stop);
 347
 348 /**
 349  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 350  * @devfreq:    the devfreq instance.
 351  *
 352  * Helper function to suspend devfreq device load monitoing. Function
 353  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 354  * event or when polling interval is set to zero.
 355  *
 356  * Note: Though this function is same as devfreq_monitor_stop(),
 357  * intentionally kept separate to provide hooks for collecting
 358  * transition statistics.
 359  */
 360 void devfreq_monitor_suspend(struct devfreq *devfreq)
 361 {
 362         mutex_lock(&devfreq->lock);
 363         if (devfreq->stop_polling) {
 364                 mutex_unlock(&devfreq->lock);
 365                 return;
 366         }
 367
 368         devfreq_update_status(devfreq, devfreq->previous_freq);
 369         devfreq->stop_polling = true;
 370         mutex_unlock(&devfreq->lock);
 371         cancel_delayed_work_sync(&devfreq->work);
 372 }
 373 EXPORT_SYMBOL(devfreq_monitor_suspend);
 374
 375 /**
 376  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 377  * @devfreq:    the devfreq instance.
 378  *
 379  * Helper function to resume devfreq device load monitoing. Function
 380  * to be called from governor in response to DEVFREQ_GOV_RESUME
 381  * event or when polling interval is set to non-zero.
 382  */
 383 void devfreq_monitor_resume(struct devfreq *devfreq)
 384 {
 385         unsigned long freq;
 386
 387         mutex_lock(&devfreq->lock);
 388         if (!devfreq->stop_polling)
 389                 goto out;
 390
 391         if (!delayed_work_pending(&devfreq->work) &&
 392                         devfreq->profile->polling_ms)
 393                 queue_delayed_work(devfreq_wq, &devfreq->work,
 394                         msecs_to_jiffies(devfreq->profile->polling_ms));
 395
 396         devfreq->last_stat_updated = jiffies;
 397         devfreq->stop_polling = false;
 398
 399         if (devfreq->profile->get_cur_freq &&
 400                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 401                 devfreq->previous_freq = freq;
 402
 403 out:
 404         mutex_unlock(&devfreq->lock);
 405 }
 406 EXPORT_SYMBOL(devfreq_monitor_resume);
 407
 408 /**
 409  * devfreq_interval_update() - Update device devfreq monitoring interval
 410  * @devfreq:    the devfreq instance.
 411  * @delay:      new polling interval to be set.
 412  *
 413  * Helper function to set new load monitoring polling interval. Function
 414  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 415  */
 416 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 417 {
 418         unsigned int cur_delay = devfreq->profile->polling_ms;
 419         unsigned int new_delay = *delay;
 420
 421         mutex_lock(&devfreq->lock);
 422         devfreq->profile->polling_ms = new_delay;
 423
 424         if (devfreq->stop_polling)
 425                 goto out;
 426
 427         /* if new delay is zero, stop polling */
 428         if (!new_delay) {
 429                 mutex_unlock(&devfreq->lock);
 430                 cancel_delayed_work_sync(&devfreq->work);
 431                 return;
 432         }
 433
 434         /* if current delay is zero, start polling with new delay */
 435         if (!cur_delay) {
 436                 queue_delayed_work(devfreq_wq, &devfreq->work,
 437                         msecs_to_jiffies(devfreq->profile->polling_ms));
 438                 goto out;
 439         }
 440
 441         /* if current delay is greater than new delay, restart polling */
 442         if (cur_delay > new_delay) {
 443                 mutex_unlock(&devfreq->lock);
 444                 cancel_delayed_work_sync(&devfreq->work);
 445                 mutex_lock(&devfreq->lock);
 446                 if (!devfreq->stop_polling)
 447                         queue_delayed_work(devfreq_wq, &devfreq->work,
 448                               msecs_to_jiffies(devfreq->profile->polling_ms));
 449         }
 450 out:
 451         mutex_unlock(&devfreq->lock);
 452 }
 453 EXPORT_SYMBOL(devfreq_interval_update);
 454
 455 /**
 456  * devfreq_notifier_call() - Notify that the device frequency requirements
 457  *                         has been changed out of devfreq framework.
 458  * @nb:         the notifier_block (supposed to be devfreq->nb)
 459  * @type:       not used
 460  * @devp:       not used
 461  *
 462  * Called by a notifier that uses devfreq->nb.
 463  */
 464 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 465                                  void *devp)
 466 {
 467         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 468         int ret;
 469
 470         mutex_lock(&devfreq->lock);
 471         ret = update_devfreq(devfreq);
 472         mutex_unlock(&devfreq->lock);
 473
 474         return ret;
 475 }
 476
 477 /**
 478  * devfreq_dev_release() - Callback for struct device to release the device.
 479  * @dev:        the devfreq device
 480  *
 481  * Remove devfreq from the list and release its resources.
 482  */
 483 static void devfreq_dev_release(struct device *dev)
 484 {
 485         struct devfreq *devfreq = to_devfreq(dev);
 486
 487         mutex_lock(&devfreq_list_lock);
 488         if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
 489                 mutex_unlock(&devfreq_list_lock);
 490                 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
 491                 return;
 492         }
 493         list_del(&devfreq->node);
 494         mutex_unlock(&devfreq_list_lock);
 495
 496         if (devfreq->governor)
 497                 devfreq->governor->event_handler(devfreq,
 498                                                  DEVFREQ_GOV_STOP, NULL);
 499
 500         if (devfreq->profile->exit)
 501                 devfreq->profile->exit(devfreq->dev.parent);
 502
 503         mutex_destroy(&devfreq->lock);
 504         kfree(devfreq);
 505 }
 506
 507 /**
 508  * devfreq_add_device() - Add devfreq feature to the device
 509  * @dev:        the device to add devfreq feature.
 510  * @profile:    device-specific profile to run devfreq.
 511  * @governor_name:      name of the policy to choose frequency.
 512  * @data:       private data for the governor. The devfreq framework does not
 513  *              touch this value.
 514  */
 515 struct devfreq *devfreq_add_device(struct device *dev,
 516                                    struct devfreq_dev_profile *profile,
 517                                    const char *governor_name,
 518                                    void *data)
 519 {
 520         struct devfreq *devfreq;
 521         struct devfreq_governor *governor;
 522         static atomic_t devfreq_no = ATOMIC_INIT(-1);
 523         int err = 0;
 524
 525         if (!dev || !profile || !governor_name) {
 526                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 527                 return ERR_PTR(-EINVAL);
 528         }
 529
 530         mutex_lock(&devfreq_list_lock);
 531         devfreq = find_device_devfreq(dev);
 532         mutex_unlock(&devfreq_list_lock);
 533         if (!IS_ERR(devfreq)) {
 534                 dev_err(dev, "%s: Unable to create devfreq for the device.\n",
 535                         __func__);
 536                 err = -EINVAL;
 537                 goto err_out;
 538         }
 539
 540         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 541         if (!devfreq) {
 542                 err = -ENOMEM;
 543                 goto err_out;
 544         }
 545
 546         mutex_init(&devfreq->lock);
 547         mutex_lock(&devfreq->lock);
 548         devfreq->dev.parent = dev;
 549         devfreq->dev.class = devfreq_class;
 550         devfreq->dev.release = devfreq_dev_release;
 551         devfreq->profile = profile;
 552         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 553         devfreq->previous_freq = profile->initial_freq;
 554         devfreq->last_status.current_frequency = profile->initial_freq;
 555         devfreq->data = data;
 556         devfreq->nb.notifier_call = devfreq_notifier_call;
 557
 558         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 559                 mutex_unlock(&devfreq->lock);
 560                 devfreq_set_freq_table(devfreq);
 561                 mutex_lock(&devfreq->lock);
 562         }
 563
 564         dev_set_name(&devfreq->dev, "devfreq%d",
 565                                 atomic_inc_return(&devfreq_no));
 566         err = device_register(&devfreq->dev);
 567         if (err) {
 568                 mutex_unlock(&devfreq->lock);
 569                 goto err_out;
 570         }
 571
 572         devfreq->trans_table =  devm_kzalloc(&devfreq->dev,
 573                                                 sizeof(unsigned int) *
 574                                                 devfreq->profile->max_state *
 575                                                 devfreq->profile->max_state,
 576                                                 GFP_KERNEL);
 577         devfreq->time_in_state = devm_kzalloc(&devfreq->dev,
 578                                                 sizeof(unsigned long) *
 579                                                 devfreq->profile->max_state,
 580                                                 GFP_KERNEL);
 581         devfreq->last_stat_updated = jiffies;
 582
 583         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 584
 585         mutex_unlock(&devfreq->lock);
 586
 587         mutex_lock(&devfreq_list_lock);
 588         list_add(&devfreq->node, &devfreq_list);
 589
 590         governor = find_devfreq_governor(devfreq->governor_name);
 591         if (IS_ERR(governor)) {
 592                 dev_err(dev, "%s: Unable to find governor for the device\n",
 593                         __func__);
 594                 err = PTR_ERR(governor);
 595                 goto err_init;
 596         }
 597
 598         devfreq->governor = governor;
 599         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 600                                                 NULL);
 601         if (err) {
 602                 dev_err(dev, "%s: Unable to start governor for the device\n",
 603                         __func__);
 604                 goto err_init;
 605         }
 606         mutex_unlock(&devfreq_list_lock);
 607
 608         return devfreq;
 609
 610 err_init:
 611         list_del(&devfreq->node);
 612         mutex_unlock(&devfreq_list_lock);
 613
 614         device_unregister(&devfreq->dev);
 615 err_out:
 616         return ERR_PTR(err);
 617 }
 618 EXPORT_SYMBOL(devfreq_add_device);
 619
 620 /**
 621  * devfreq_remove_device() - Remove devfreq feature from a device.
 622  * @devfreq:    the devfreq instance to be removed
 623  *
 624  * The opposite of devfreq_add_device().
 625  */
 626 int devfreq_remove_device(struct devfreq *devfreq)
 627 {
 628         if (!devfreq)
 629                 return -EINVAL;
 630
 631         device_unregister(&devfreq->dev);
 632
 633         return 0;
 634 }
 635 EXPORT_SYMBOL(devfreq_remove_device);
 636
 637 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 638 {
 639         struct devfreq **r = res;
 640
 641         if (WARN_ON(!r || !*r))
 642                 return 0;
 643
 644         return *r == data;
 645 }
 646
 647 static void devm_devfreq_dev_release(struct device *dev, void *res)
 648 {
 649         devfreq_remove_device(*(struct devfreq **)res);
 650 }
 651
 652 /**
 653  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 654  * @dev:        the device to add devfreq feature.
 655  * @profile:    device-specific profile to run devfreq.
 656  * @governor_name:      name of the policy to choose frequency.
 657  * @data:       private data for the governor. The devfreq framework does not
 658  *              touch this value.
 659  *
 660  * This function manages automatically the memory of devfreq device using device
 661  * resource management and simplify the free operation for memory of devfreq
 662  * device.
 663  */
 664 struct devfreq *devm_devfreq_add_device(struct device *dev,
 665                                         struct devfreq_dev_profile *profile,
 666                                         const char *governor_name,
 667                                         void *data)
 668 {
 669         struct devfreq **ptr, *devfreq;
 670
 671         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 672         if (!ptr)
 673                 return ERR_PTR(-ENOMEM);
 674
 675         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 676         if (IS_ERR(devfreq)) {
 677                 devres_free(ptr);
 678                 return ERR_PTR(-ENOMEM);
 679         }
 680
 681         *ptr = devfreq;
 682         devres_add(dev, ptr);
 683
 684         return devfreq;
 685 }
 686 EXPORT_SYMBOL(devm_devfreq_add_device);
 687
 688 #ifdef CONFIG_OF
 689 /*
 690  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 691  * @dev - instance to the given device
 692  * @index - index into list of devfreq
 693  *
 694  * return the instance of devfreq device
 695  */
 696 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 697 {
 698         struct device_node *node;
 699         struct devfreq *devfreq;
 700
 701         if (!dev)
 702                 return ERR_PTR(-EINVAL);
 703
 704         if (!dev->of_node)
 705                 return ERR_PTR(-EINVAL);
 706
 707         node = of_parse_phandle(dev->of_node, "devfreq", index);
 708         if (!node)
 709                 return ERR_PTR(-ENODEV);
 710
 711         mutex_lock(&devfreq_list_lock);
 712         list_for_each_entry(devfreq, &devfreq_list, node) {
 713                 if (devfreq->dev.parent
 714                         && devfreq->dev.parent->of_node == node) {
 715                         mutex_unlock(&devfreq_list_lock);
 716                         of_node_put(node);
 717                         return devfreq;
 718                 }
 719         }
 720         mutex_unlock(&devfreq_list_lock);
 721         of_node_put(node);
 722
 723         return ERR_PTR(-EPROBE_DEFER);
 724 }
 725 #else
 726 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 727 {
 728         return ERR_PTR(-ENODEV);
 729 }
 730 #endif /* CONFIG_OF */
 731 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 732
 733 /**
 734  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 735  * @dev:        the device to add devfreq feature.
 736  * @devfreq:    the devfreq instance to be removed
 737  */
 738 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 739 {
 740         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 741                                devm_devfreq_dev_match, devfreq));
 742 }
 743 EXPORT_SYMBOL(devm_devfreq_remove_device);
 744
 745 /**
 746  * devfreq_suspend_device() - Suspend devfreq of a device.
 747  * @devfreq: the devfreq instance to be suspended
 748  *
 749  * This function is intended to be called by the pm callbacks
 750  * (e.g., runtime_suspend, suspend) of the device driver that
 751  * holds the devfreq.
 752  */
 753 int devfreq_suspend_device(struct devfreq *devfreq)
 754 {
 755         if (!devfreq)
 756                 return -EINVAL;
 757
 758         if (!devfreq->governor)
 759                 return 0;
 760
 761         return devfreq->governor->event_handler(devfreq,
 762                                 DEVFREQ_GOV_SUSPEND, NULL);
 763 }
 764 EXPORT_SYMBOL(devfreq_suspend_device);
 765
 766 /**
 767  * devfreq_resume_device() - Resume devfreq of a device.
 768  * @devfreq: the devfreq instance to be resumed
 769  *
 770  * This function is intended to be called by the pm callbacks
 771  * (e.g., runtime_resume, resume) of the device driver that
 772  * holds the devfreq.
 773  */
 774 int devfreq_resume_device(struct devfreq *devfreq)
 775 {
 776         if (!devfreq)
 777                 return -EINVAL;
 778
 779         if (!devfreq->governor)
 780                 return 0;
 781
 782         return devfreq->governor->event_handler(devfreq,
 783                                 DEVFREQ_GOV_RESUME, NULL);
 784 }
 785 EXPORT_SYMBOL(devfreq_resume_device);
 786
 787 /**
 788  * devfreq_add_governor() - Add devfreq governor
 789  * @governor:   the devfreq governor to be added
 790  */
 791 int devfreq_add_governor(struct devfreq_governor *governor)
 792 {
 793         struct devfreq_governor *g;
 794         struct devfreq *devfreq;
 795         int err = 0;
 796
 797         if (!governor) {
 798                 pr_err("%s: Invalid parameters.\n", __func__);
 799                 return -EINVAL;
 800         }
 801
 802         mutex_lock(&devfreq_list_lock);
 803         g = find_devfreq_governor(governor->name);
 804         if (!IS_ERR(g)) {
 805                 pr_err("%s: governor %s already registered\n", __func__,
 806                        g->name);
 807                 err = -EINVAL;
 808                 goto err_out;
 809         }
 810
 811         list_add(&governor->node, &devfreq_governor_list);
 812
 813         list_for_each_entry(devfreq, &devfreq_list, node) {
 814                 int ret = 0;
 815                 struct device *dev = devfreq->dev.parent;
 816
 817                 if (!strncmp(devfreq->governor_name, governor->name,
 818                              DEVFREQ_NAME_LEN)) {
 819                         /* The following should never occur */
 820                         if (devfreq->governor) {
 821                                 dev_warn(dev,
 822                                          "%s: Governor %s already present\n",
 823                                          __func__, devfreq->governor->name);
 824                                 ret = devfreq->governor->event_handler(devfreq,
 825                                                         DEVFREQ_GOV_STOP, NULL);
 826                                 if (ret) {
 827                                         dev_warn(dev,
 828                                                  "%s: Governor %s stop = %d\n",
 829                                                  __func__,
 830                                                  devfreq->governor->name, ret);
 831                                 }
 832                                 /* Fall through */
 833                         }
 834                         devfreq->governor = governor;
 835                         ret = devfreq->governor->event_handler(devfreq,
 836                                                 DEVFREQ_GOV_START, NULL);
 837                         if (ret) {
 838                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 839                                          __func__, devfreq->governor->name,
 840                                          ret);
 841                         }
 842                 }
 843         }
 844
 845 err_out:
 846         mutex_unlock(&devfreq_list_lock);
 847
 848         return err;
 849 }
 850 EXPORT_SYMBOL(devfreq_add_governor);
 851
 852 /**
 853  * devfreq_remove_governor() - Remove devfreq feature from a device.
 854  * @governor:   the devfreq governor to be removed
 855  */
 856 int devfreq_remove_governor(struct devfreq_governor *governor)
 857 {
 858         struct devfreq_governor *g;
 859         struct devfreq *devfreq;
 860         int err = 0;
 861
 862         if (!governor) {
 863                 pr_err("%s: Invalid parameters.\n", __func__);
 864                 return -EINVAL;
 865         }
 866
 867         mutex_lock(&devfreq_list_lock);
 868         g = find_devfreq_governor(governor->name);
 869         if (IS_ERR(g)) {
 870                 pr_err("%s: governor %s not registered\n", __func__,
 871                        governor->name);
 872                 err = PTR_ERR(g);
 873                 goto err_out;
 874         }
 875         list_for_each_entry(devfreq, &devfreq_list, node) {
 876                 int ret;
 877                 struct device *dev = devfreq->dev.parent;
 878
 879                 if (!strncmp(devfreq->governor_name, governor->name,
 880                              DEVFREQ_NAME_LEN)) {
 881                         /* we should have a devfreq governor! */
 882                         if (!devfreq->governor) {
 883                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 884                                          __func__, governor->name);
 885                                 continue;
 886                                 /* Fall through */
 887                         }
 888                         ret = devfreq->governor->event_handler(devfreq,
 889                                                 DEVFREQ_GOV_STOP, NULL);
 890                         if (ret) {
 891                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 892                                          __func__, devfreq->governor->name,
 893                                          ret);
 894                         }
 895                         devfreq->governor = NULL;
 896                 }
 897         }
 898
 899         list_del(&governor->node);
 900 err_out:
 901         mutex_unlock(&devfreq_list_lock);
 902
 903         return err;
 904 }
 905 EXPORT_SYMBOL(devfreq_remove_governor);
 906
 907 static ssize_t governor_show(struct device *dev,
 908                              struct device_attribute *attr, char *buf)
 909 {
 910         if (!to_devfreq(dev)->governor)
 911                 return -EINVAL;
 912
 913         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 914 }
 915
 916 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 917                               const char *buf, size_t count)
 918 {
 919         struct devfreq *df = to_devfreq(dev);
 920         int ret;
 921         char str_governor[DEVFREQ_NAME_LEN + 1];
 922         struct devfreq_governor *governor;
 923
 924         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 925         if (ret != 1)
 926                 return -EINVAL;
 927
 928         mutex_lock(&devfreq_list_lock);
 929         governor = find_devfreq_governor(str_governor);
 930         if (IS_ERR(governor)) {
 931                 ret = PTR_ERR(governor);
 932                 goto out;
 933         }
 934         if (df->governor == governor) {
 935                 ret = 0;
 936                 goto out;
 937         } else if (df->governor->immutable || governor->immutable) {
 938                 ret = -EINVAL;
 939                 goto out;
 940         }
 941
 942         if (df->governor) {
 943                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
 944                 if (ret) {
 945                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
 946                                  __func__, df->governor->name, ret);
 947                         goto out;
 948                 }
 949         }
 950         df->governor = governor;
 951         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
 952         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
 953         if (ret)
 954                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
 955                          __func__, df->governor->name, ret);
 956 out:
 957         mutex_unlock(&devfreq_list_lock);
 958
 959         if (!ret)
 960                 ret = count;
 961         return ret;
 962 }
 963 static DEVICE_ATTR_RW(governor);
 964
 965 static ssize_t available_governors_show(struct device *d,
 966                                         struct device_attribute *attr,
 967                                         char *buf)
 968 {
 969         struct devfreq *df = to_devfreq(d);
 970         ssize_t count = 0;
 971
 972         mutex_lock(&devfreq_list_lock);
 973
 974         /*
 975          * The devfreq with immutable governor (e.g., passive) shows
 976          * only own governor.
 977          */
 978         if (df->governor->immutable) {
 979                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
 980                                    "%s ", df->governor_name);
 981         /*
 982          * The devfreq device shows the registered governor except for
 983          * immutable governors such as passive governor .
 984          */
 985         } else {
 986                 struct devfreq_governor *governor;
 987
 988                 list_for_each_entry(governor, &devfreq_governor_list, node) {
 989                         if (governor->immutable)
 990                                 continue;
 991                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
 992                                            "%s ", governor->name);
 993                 }
 994         }
 995
 996         mutex_unlock(&devfreq_list_lock);
 997
 998         /* Truncate the trailing space */
 999         if (count)
1000                 count--;
1001
1002         count += sprintf(&buf[count], "\n");
1003
1004         return count;
1005 }
1006 static DEVICE_ATTR_RO(available_governors);
1007
1008 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1009                              char *buf)
1010 {
1011         unsigned long freq;
1012         struct devfreq *devfreq = to_devfreq(dev);
1013
1014         if (devfreq->profile->get_cur_freq &&
1015                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1016                 return sprintf(buf, "%lu\n", freq);
1017
1018         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1019 }
1020 static DEVICE_ATTR_RO(cur_freq);
1021
1022 static ssize_t target_freq_show(struct device *dev,
1023                                 struct device_attribute *attr, char *buf)
1024 {
1025         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1026 }
1027 static DEVICE_ATTR_RO(target_freq);
1028
1029 static ssize_t polling_interval_show(struct device *dev,
1030                                      struct device_attribute *attr, char *buf)
1031 {
1032         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1033 }
1034
1035 static ssize_t polling_interval_store(struct device *dev,
1036                                       struct device_attribute *attr,
1037                                       const char *buf, size_t count)
1038 {
1039         struct devfreq *df = to_devfreq(dev);
1040         unsigned int value;
1041         int ret;
1042
1043         if (!df->governor)
1044                 return -EINVAL;
1045
1046         ret = sscanf(buf, "%u", &value);
1047         if (ret != 1)
1048                 return -EINVAL;
1049
1050         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1051         ret = count;
1052
1053         return ret;
1054 }
1055 static DEVICE_ATTR_RW(polling_interval);
1056
1057 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1058                               const char *buf, size_t count)
1059 {
1060         struct devfreq *df = to_devfreq(dev);
1061         unsigned long value;
1062         int ret;
1063         unsigned long max;
1064
1065         ret = sscanf(buf, "%lu", &value);
1066         if (ret != 1)
1067                 return -EINVAL;
1068
1069         mutex_lock(&df->lock);
1070         max = df->max_freq;
1071         if (value && max && value > max) {
1072                 ret = -EINVAL;
1073                 goto unlock;
1074         }
1075
1076         df->min_freq = value;
1077         update_devfreq(df);
1078         ret = count;
1079 unlock:
1080         mutex_unlock(&df->lock);
1081         return ret;
1082 }
1083
1084 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1085                               const char *buf, size_t count)
1086 {
1087         struct devfreq *df = to_devfreq(dev);
1088         unsigned long value;
1089         int ret;
1090         unsigned long min;
1091
1092         ret = sscanf(buf, "%lu", &value);
1093         if (ret != 1)
1094                 return -EINVAL;
1095
1096         mutex_lock(&df->lock);
1097         min = df->min_freq;
1098         if (value && min && value < min) {
1099                 ret = -EINVAL;
1100                 goto unlock;
1101         }
1102
1103         df->max_freq = value;
1104         update_devfreq(df);
1105         ret = count;
1106 unlock:
1107         mutex_unlock(&df->lock);
1108         return ret;
1109 }
1110
1111 #define show_one(name)                                          \
1112 static ssize_t name##_show                                      \
1113 (struct device *dev, struct device_attribute *attr, char *buf)  \
1114 {                                                               \
1115         return sprintf(buf, "%lu\n", to_devfreq(dev)->name);    \
1116 }
1117 show_one(min_freq);
1118 show_one(max_freq);
1119
1120 static DEVICE_ATTR_RW(min_freq);
1121 static DEVICE_ATTR_RW(max_freq);
1122
1123 static ssize_t available_frequencies_show(struct device *d,
1124                                           struct device_attribute *attr,
1125                                           char *buf)
1126 {
1127         struct devfreq *df = to_devfreq(d);
1128         struct device *dev = df->dev.parent;
1129         struct dev_pm_opp *opp;
1130         ssize_t count = 0;
1131         unsigned long freq = 0;
1132
1133         rcu_read_lock();
1134         do {
1135                 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1136                 if (IS_ERR(opp))
1137                         break;
1138
1139                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1140                                    "%lu ", freq);
1141                 freq++;
1142         } while (1);
1143         rcu_read_unlock();
1144
1145         /* Truncate the trailing space */
1146         if (count)
1147                 count--;
1148
1149         count += sprintf(&buf[count], "\n");
1150
1151         return count;
1152 }
1153 static DEVICE_ATTR_RO(available_frequencies);
1154
1155 static ssize_t trans_stat_show(struct device *dev,
1156                                struct device_attribute *attr, char *buf)
1157 {
1158         struct devfreq *devfreq = to_devfreq(dev);
1159         ssize_t len;
1160         int i, j;
1161         unsigned int max_state = devfreq->profile->max_state;
1162
1163         if (!devfreq->stop_polling &&
1164                         devfreq_update_status(devfreq, devfreq->previous_freq))
1165                 return 0;
1166         if (max_state == 0)
1167                 return sprintf(buf, "Not Supported.\n");
1168
1169         len = sprintf(buf, "     From  :   To\n");
1170         len += sprintf(buf + len, "           :");
1171         for (i = 0; i < max_state; i++)
1172                 len += sprintf(buf + len, "%10lu",
1173                                 devfreq->profile->freq_table[i]);
1174
1175         len += sprintf(buf + len, "   time(ms)\n");
1176
1177         for (i = 0; i < max_state; i++) {
1178                 if (devfreq->profile->freq_table[i]
1179                                         == devfreq->previous_freq) {
1180                         len += sprintf(buf + len, "*");
1181                 } else {
1182                         len += sprintf(buf + len, " ");
1183                 }
1184                 len += sprintf(buf + len, "%10lu:",
1185                                 devfreq->profile->freq_table[i]);
1186                 for (j = 0; j < max_state; j++)
1187                         len += sprintf(buf + len, "%10u",
1188                                 devfreq->trans_table[(i * max_state) + j]);
1189                 len += sprintf(buf + len, "%10u\n",
1190                         jiffies_to_msecs(devfreq->time_in_state[i]));
1191         }
1192
1193         len += sprintf(buf + len, "Total transition : %u\n",
1194                                         devfreq->total_trans);
1195         return len;
1196 }
1197 static DEVICE_ATTR_RO(trans_stat);
1198
1199 static struct attribute *devfreq_attrs[] = {
1200         &dev_attr_governor.attr,
1201         &dev_attr_available_governors.attr,
1202         &dev_attr_cur_freq.attr,
1203         &dev_attr_available_frequencies.attr,
1204         &dev_attr_target_freq.attr,
1205         &dev_attr_polling_interval.attr,
1206         &dev_attr_min_freq.attr,
1207         &dev_attr_max_freq.attr,
1208         &dev_attr_trans_stat.attr,
1209         NULL,
1210 };
1211 ATTRIBUTE_GROUPS(devfreq);
1212
1213 static int __init devfreq_init(void)
1214 {
1215         devfreq_class = class_create(THIS_MODULE, "devfreq");
1216         if (IS_ERR(devfreq_class)) {
1217                 pr_err("%s: couldn't create class\n", __FILE__);
1218                 return PTR_ERR(devfreq_class);
1219         }
1220
1221         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1222         if (!devfreq_wq) {
1223                 class_destroy(devfreq_class);
1224                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1225                 return -ENOMEM;
1226         }
1227         devfreq_class->dev_groups = devfreq_groups;
1228
1229         return 0;
1230 }
1231 subsys_initcall(devfreq_init);
1232
1233 /*
1234  * The followings are helper functions for devfreq user device drivers with
1235  * OPP framework.
1236  */
1237
1238 /**
1239  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1240  *                           freq value given to target callback.
1241  * @dev:        The devfreq user device. (parent of devfreq)
1242  * @freq:       The frequency given to target function
1243  * @flags:      Flags handed from devfreq framework.
1244  *
1245  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1246  * protected pointer. The reason for the same is that the opp pointer which is
1247  * returned will remain valid for use with opp_get_{voltage, freq} only while
1248  * under the locked area. The pointer returned must be used prior to unlocking
1249  * with rcu_read_unlock() to maintain the integrity of the pointer.
1250  */
1251 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1252                                            unsigned long *freq,
1253                                            u32 flags)
1254 {
1255         struct dev_pm_opp *opp;
1256
1257         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1258                 /* The freq is an upper bound. opp should be lower */
1259                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1260
1261                 /* If not available, use the closest opp */
1262                 if (opp == ERR_PTR(-ERANGE))
1263                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1264         } else {
1265                 /* The freq is an lower bound. opp should be higher */
1266                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1267
1268                 /* If not available, use the closest opp */
1269                 if (opp == ERR_PTR(-ERANGE))
1270                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1271         }
1272
1273         return opp;
1274 }
1275 EXPORT_SYMBOL(devfreq_recommended_opp);
1276
1277 /**
1278  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1279  *                                 for any changes in the OPP availability
1280  *                                 changes
1281  * @dev:        The devfreq user device. (parent of devfreq)
1282  * @devfreq:    The devfreq object.
1283  */
1284 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1285 {
1286         struct srcu_notifier_head *nh;
1287         int ret = 0;
1288
1289         rcu_read_lock();
1290         nh = dev_pm_opp_get_notifier(dev);
1291         if (IS_ERR(nh))
1292                 ret = PTR_ERR(nh);
1293         rcu_read_unlock();
1294         if (!ret)
1295                 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1296
1297         return ret;
1298 }
1299 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1300
1301 /**
1302  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1303  *                                   notified for any changes in the OPP
1304  *                                   availability changes anymore.
1305  * @dev:        The devfreq user device. (parent of devfreq)
1306  * @devfreq:    The devfreq object.
1307  *
1308  * At exit() callback of devfreq_dev_profile, this must be included if
1309  * devfreq_recommended_opp is used.
1310  */
1311 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1312 {
1313         struct srcu_notifier_head *nh;
1314         int ret = 0;
1315
1316         rcu_read_lock();
1317         nh = dev_pm_opp_get_notifier(dev);
1318         if (IS_ERR(nh))
1319                 ret = PTR_ERR(nh);
1320         rcu_read_unlock();
1321         if (!ret)
1322                 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1323
1324         return ret;
1325 }
1326 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1327
1328 static void devm_devfreq_opp_release(struct device *dev, void *res)
1329 {
1330         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1331 }
1332
1333 /**
1334  * devm_ devfreq_register_opp_notifier()
1335  *              - Resource-managed devfreq_register_opp_notifier()
1336  * @dev:        The devfreq user device. (parent of devfreq)
1337  * @devfreq:    The devfreq object.
1338  */
1339 int devm_devfreq_register_opp_notifier(struct device *dev,
1340                                        struct devfreq *devfreq)
1341 {
1342         struct devfreq **ptr;
1343         int ret;
1344
1345         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1346         if (!ptr)
1347                 return -ENOMEM;
1348
1349         ret = devfreq_register_opp_notifier(dev, devfreq);
1350         if (ret) {
1351                 devres_free(ptr);
1352                 return ret;
1353         }
1354
1355         *ptr = devfreq;
1356         devres_add(dev, ptr);
1357
1358         return 0;
1359 }
1360 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1361
1362 /**
1363  * devm_devfreq_unregister_opp_notifier()
1364  *              - Resource-managed devfreq_unregister_opp_notifier()
1365  * @dev:        The devfreq user device. (parent of devfreq)
1366  * @devfreq:    The devfreq object.
1367  */
1368 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1369                                          struct devfreq *devfreq)
1370 {
1371         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1372                                devm_devfreq_dev_match, devfreq));
1373 }
1374 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1375
1376 /**
1377  * devfreq_register_notifier() - Register a driver with devfreq
1378  * @devfreq:    The devfreq object.
1379  * @nb:         The notifier block to register.
1380  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1381  */
1382 int devfreq_register_notifier(struct devfreq *devfreq,
1383                                 struct notifier_block *nb,
1384                                 unsigned int list)
1385 {
1386         int ret = 0;
1387
1388         if (!devfreq)
1389                 return -EINVAL;
1390
1391         switch (list) {
1392         case DEVFREQ_TRANSITION_NOTIFIER:
1393                 ret = srcu_notifier_chain_register(
1394                                 &devfreq->transition_notifier_list, nb);
1395                 break;
1396         default:
1397                 ret = -EINVAL;
1398         }
1399
1400         return ret;
1401 }
1402 EXPORT_SYMBOL(devfreq_register_notifier);
1403
1404 /*
1405  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1406  * @devfreq:    The devfreq object.
1407  * @nb:         The notifier block to be unregistered.
1408  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1409  */
1410 int devfreq_unregister_notifier(struct devfreq *devfreq,
1411                                 struct notifier_block *nb,
1412                                 unsigned int list)
1413 {
1414         int ret = 0;
1415
1416         if (!devfreq)
1417                 return -EINVAL;
1418
1419         switch (list) {
1420         case DEVFREQ_TRANSITION_NOTIFIER:
1421                 ret = srcu_notifier_chain_unregister(
1422                                 &devfreq->transition_notifier_list, nb);
1423                 break;
1424         default:
1425                 ret = -EINVAL;
1426         }
1427
1428         return ret;
1429 }
1430 EXPORT_SYMBOL(devfreq_unregister_notifier);
1431
1432 struct devfreq_notifier_devres {
1433         struct devfreq *devfreq;
1434         struct notifier_block *nb;
1435         unsigned int list;
1436 };
1437
1438 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1439 {
1440         struct devfreq_notifier_devres *this = res;
1441
1442         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1443 }
1444
1445 /**
1446  * devm_devfreq_register_notifier()
1447         - Resource-managed devfreq_register_notifier()
1448  * @dev:        The devfreq user device. (parent of devfreq)
1449  * @devfreq:    The devfreq object.
1450  * @nb:         The notifier block to be unregistered.
1451  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1452  */
1453 int devm_devfreq_register_notifier(struct device *dev,
1454                                 struct devfreq *devfreq,
1455                                 struct notifier_block *nb,
1456                                 unsigned int list)
1457 {
1458         struct devfreq_notifier_devres *ptr;
1459         int ret;
1460
1461         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1462                                 GFP_KERNEL);
1463         if (!ptr)
1464                 return -ENOMEM;
1465
1466         ret = devfreq_register_notifier(devfreq, nb, list);
1467         if (ret) {
1468                 devres_free(ptr);
1469                 return ret;
1470         }
1471
1472         ptr->devfreq = devfreq;
1473         ptr->nb = nb;
1474         ptr->list = list;
1475         devres_add(dev, ptr);
1476
1477         return 0;
1478 }
1479 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1480
1481 /**
1482  * devm_devfreq_unregister_notifier()
1483         - Resource-managed devfreq_unregister_notifier()
1484  * @dev:        The devfreq user device. (parent of devfreq)
1485  * @devfreq:    The devfreq object.
1486  * @nb:         The notifier block to be unregistered.
1487  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1488  */
1489 void devm_devfreq_unregister_notifier(struct device *dev,
1490                                 struct devfreq *devfreq,
1491                                 struct notifier_block *nb,
1492                                 unsigned int list)
1493 {
1494         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1495                                devm_devfreq_dev_match, devfreq));
1496 }
1497 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);