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 <[email protected]>
   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 #define MAX(a,b)        ((a > b) ? a : b)
  32 #define MIN(a,b)        ((a < b) ? a : b)
  33
  34 static struct class *devfreq_class;
  35
  36 /*
  37  * devfreq core provides delayed work based load monitoring helper
  38  * functions. Governors can use these or can implement their own
  39  * monitoring mechanism.
  40  */
  41 static struct workqueue_struct *devfreq_wq;
  42
  43 /* The list of all device-devfreq governors */
  44 static LIST_HEAD(devfreq_governor_list);
  45 /* The list of all device-devfreq */
  46 static LIST_HEAD(devfreq_list);
  47 static DEFINE_MUTEX(devfreq_list_lock);
  48
  49 /**
  50  * find_device_devfreq() - find devfreq struct using device pointer
  51  * @dev:        device pointer used to lookup device devfreq.
  52  *
  53  * Search the list of device devfreqs and return the matched device's
  54  * devfreq info. devfreq_list_lock should be held by the caller.
  55  */
  56 static struct devfreq *find_device_devfreq(struct device *dev)
  57 {
  58         struct devfreq *tmp_devfreq;
  59
  60         if (IS_ERR_OR_NULL(dev)) {
  61                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  62                 return ERR_PTR(-EINVAL);
  63         }
  64         WARN(!mutex_is_locked(&devfreq_list_lock),
  65              "devfreq_list_lock must be locked.");
  66
  67         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  68                 if (tmp_devfreq->dev.parent == dev)
  69                         return tmp_devfreq;
  70         }
  71
  72         return ERR_PTR(-ENODEV);
  73 }
  74
  75 static unsigned long find_available_min_freq(struct devfreq *devfreq)
  76 {
  77         struct dev_pm_opp *opp;
  78         unsigned long min_freq = 0;
  79
  80         opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
  81         if (IS_ERR(opp))
  82                 min_freq = 0;
  83         else
  84                 dev_pm_opp_put(opp);
  85
  86         return min_freq;
  87 }
  88
  89 static unsigned long find_available_max_freq(struct devfreq *devfreq)
  90 {
  91         struct dev_pm_opp *opp;
  92         unsigned long max_freq = ULONG_MAX;
  93
  94         opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
  95         if (IS_ERR(opp))
  96                 max_freq = 0;
  97         else
  98                 dev_pm_opp_put(opp);
  99
 100         return max_freq;
 101 }
 102
 103 /**
 104  * devfreq_get_freq_level() - Lookup freq_table for the frequency
 105  * @devfreq:    the devfreq instance
 106  * @freq:       the target frequency
 107  */
 108 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 109 {
 110         int lev;
 111
 112         for (lev = 0; lev < devfreq->profile->max_state; lev++)
 113                 if (freq == devfreq->profile->freq_table[lev])
 114                         return lev;
 115
 116         return -EINVAL;
 117 }
 118
 119 static int set_freq_table(struct devfreq *devfreq)
 120 {
 121         struct devfreq_dev_profile *profile = devfreq->profile;
 122         struct dev_pm_opp *opp;
 123         unsigned long freq;
 124         int i, count;
 125
 126         /* Initialize the freq_table from OPP table */
 127         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 128         if (count <= 0)
 129                 return -EINVAL;
 130
 131         profile->max_state = count;
 132         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 133                                         profile->max_state,
 134                                         sizeof(*profile->freq_table),
 135                                         GFP_KERNEL);
 136         if (!profile->freq_table) {
 137                 profile->max_state = 0;
 138                 return -ENOMEM;
 139         }
 140
 141         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 142                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 143                 if (IS_ERR(opp)) {
 144                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 145                         profile->max_state = 0;
 146                         return PTR_ERR(opp);
 147                 }
 148                 dev_pm_opp_put(opp);
 149                 profile->freq_table[i] = freq;
 150         }
 151
 152         return 0;
 153 }
 154
 155 /**
 156  * devfreq_update_status() - Update statistics of devfreq behavior
 157  * @devfreq:    the devfreq instance
 158  * @freq:       the update target frequency
 159  */
 160 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 161 {
 162         int lev, prev_lev, ret = 0;
 163         unsigned long cur_time;
 164
 165         cur_time = jiffies;
 166
 167         /* Immediately exit if previous_freq is not initialized yet. */
 168         if (!devfreq->previous_freq)
 169                 goto out;
 170
 171         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 172         if (prev_lev < 0) {
 173                 ret = prev_lev;
 174                 goto out;
 175         }
 176
 177         devfreq->time_in_state[prev_lev] +=
 178                          cur_time - devfreq->last_stat_updated;
 179
 180         lev = devfreq_get_freq_level(devfreq, freq);
 181         if (lev < 0) {
 182                 ret = lev;
 183                 goto out;
 184         }
 185
 186         if (lev != prev_lev) {
 187                 devfreq->trans_table[(prev_lev *
 188                                 devfreq->profile->max_state) + lev]++;
 189                 devfreq->total_trans++;
 190         }
 191
 192 out:
 193         devfreq->last_stat_updated = cur_time;
 194         return ret;
 195 }
 196 EXPORT_SYMBOL(devfreq_update_status);
 197
 198 /**
 199  * find_devfreq_governor() - find devfreq governor from name
 200  * @name:       name of the governor
 201  *
 202  * Search the list of devfreq governors and return the matched
 203  * governor's pointer. devfreq_list_lock should be held by the caller.
 204  */
 205 static struct devfreq_governor *find_devfreq_governor(const char *name)
 206 {
 207         struct devfreq_governor *tmp_governor;
 208
 209         if (IS_ERR_OR_NULL(name)) {
 210                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 211                 return ERR_PTR(-EINVAL);
 212         }
 213         WARN(!mutex_is_locked(&devfreq_list_lock),
 214              "devfreq_list_lock must be locked.");
 215
 216         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 217                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 218                         return tmp_governor;
 219         }
 220
 221         return ERR_PTR(-ENODEV);
 222 }
 223
 224 static int devfreq_notify_transition(struct devfreq *devfreq,
 225                 struct devfreq_freqs *freqs, unsigned int state)
 226 {
 227         if (!devfreq)
 228                 return -EINVAL;
 229
 230         switch (state) {
 231         case DEVFREQ_PRECHANGE:
 232                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 233                                 DEVFREQ_PRECHANGE, freqs);
 234                 break;
 235
 236         case DEVFREQ_POSTCHANGE:
 237                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 238                                 DEVFREQ_POSTCHANGE, freqs);
 239                 break;
 240         default:
 241                 return -EINVAL;
 242         }
 243
 244         return 0;
 245 }
 246
 247 /* Load monitoring helper functions for governors use */
 248
 249 /**
 250  * update_devfreq() - Reevaluate the device and configure frequency.
 251  * @devfreq:    the devfreq instance.
 252  *
 253  * Note: Lock devfreq->lock before calling update_devfreq
 254  *       This function is exported for governors.
 255  */
 256 int update_devfreq(struct devfreq *devfreq)
 257 {
 258         struct devfreq_freqs freqs;
 259         unsigned long freq, cur_freq, min_freq, max_freq;
 260         int err = 0;
 261         u32 flags = 0;
 262
 263         if (!mutex_is_locked(&devfreq->lock)) {
 264                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 265                 return -EINVAL;
 266         }
 267
 268         if (!devfreq->governor)
 269                 return -EINVAL;
 270
 271         /* Reevaluate the proper frequency */
 272         err = devfreq->governor->get_target_freq(devfreq, &freq);
 273         if (err)
 274                 return err;
 275
 276         /*
 277          * Adjust the frequency with user freq, QoS and available freq.
 278          *
 279          * List from the highest priority
 280          * max_freq
 281          * min_freq
 282          */
 283         max_freq = MIN(devfreq->scaling_max_freq, devfreq->max_freq);
 284         min_freq = MAX(devfreq->scaling_min_freq, devfreq->min_freq);
 285
 286         if (min_freq && freq < min_freq) {
 287                 freq = min_freq;
 288                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 289         }
 290         if (max_freq && freq > max_freq) {
 291                 freq = max_freq;
 292                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 293         }
 294
 295         if (devfreq->profile->get_cur_freq)
 296                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 297         else
 298                 cur_freq = devfreq->previous_freq;
 299
 300         freqs.old = cur_freq;
 301         freqs.new = freq;
 302         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 303
 304         err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 305         if (err) {
 306                 freqs.new = cur_freq;
 307                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 308                 return err;
 309         }
 310
 311         freqs.new = freq;
 312         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 313
 314         if (devfreq_update_status(devfreq, freq))
 315                 dev_err(&devfreq->dev,
 316                         "Couldn't update frequency transition information.\n");
 317
 318         devfreq->previous_freq = freq;
 319         return err;
 320 }
 321 EXPORT_SYMBOL(update_devfreq);
 322
 323 /**
 324  * devfreq_monitor() - Periodically poll devfreq objects.
 325  * @work:       the work struct used to run devfreq_monitor periodically.
 326  *
 327  */
 328 static void devfreq_monitor(struct work_struct *work)
 329 {
 330         int err;
 331         struct devfreq *devfreq = container_of(work,
 332                                         struct devfreq, work.work);
 333
 334         mutex_lock(&devfreq->lock);
 335         err = update_devfreq(devfreq);
 336         if (err)
 337                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 338
 339         queue_delayed_work(devfreq_wq, &devfreq->work,
 340                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 341         mutex_unlock(&devfreq->lock);
 342 }
 343
 344 /**
 345  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 346  * @devfreq:    the devfreq instance.
 347  *
 348  * Helper function for starting devfreq device load monitoing. By
 349  * default delayed work based monitoring is supported. Function
 350  * to be called from governor in response to DEVFREQ_GOV_START
 351  * event when device is added to devfreq framework.
 352  */
 353 void devfreq_monitor_start(struct devfreq *devfreq)
 354 {
 355         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 356         if (devfreq->profile->polling_ms)
 357                 queue_delayed_work(devfreq_wq, &devfreq->work,
 358                         msecs_to_jiffies(devfreq->profile->polling_ms));
 359 }
 360 EXPORT_SYMBOL(devfreq_monitor_start);
 361
 362 /**
 363  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 364  * @devfreq:    the devfreq instance.
 365  *
 366  * Helper function to stop devfreq device load monitoing. Function
 367  * to be called from governor in response to DEVFREQ_GOV_STOP
 368  * event when device is removed from devfreq framework.
 369  */
 370 void devfreq_monitor_stop(struct devfreq *devfreq)
 371 {
 372         cancel_delayed_work_sync(&devfreq->work);
 373 }
 374 EXPORT_SYMBOL(devfreq_monitor_stop);
 375
 376 /**
 377  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 378  * @devfreq:    the devfreq instance.
 379  *
 380  * Helper function to suspend devfreq device load monitoing. Function
 381  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 382  * event or when polling interval is set to zero.
 383  *
 384  * Note: Though this function is same as devfreq_monitor_stop(),
 385  * intentionally kept separate to provide hooks for collecting
 386  * transition statistics.
 387  */
 388 void devfreq_monitor_suspend(struct devfreq *devfreq)
 389 {
 390         mutex_lock(&devfreq->lock);
 391         if (devfreq->stop_polling) {
 392                 mutex_unlock(&devfreq->lock);
 393                 return;
 394         }
 395
 396         devfreq_update_status(devfreq, devfreq->previous_freq);
 397         devfreq->stop_polling = true;
 398         mutex_unlock(&devfreq->lock);
 399         cancel_delayed_work_sync(&devfreq->work);
 400 }
 401 EXPORT_SYMBOL(devfreq_monitor_suspend);
 402
 403 /**
 404  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 405  * @devfreq:    the devfreq instance.
 406  *
 407  * Helper function to resume devfreq device load monitoing. Function
 408  * to be called from governor in response to DEVFREQ_GOV_RESUME
 409  * event or when polling interval is set to non-zero.
 410  */
 411 void devfreq_monitor_resume(struct devfreq *devfreq)
 412 {
 413         unsigned long freq;
 414
 415         mutex_lock(&devfreq->lock);
 416         if (!devfreq->stop_polling)
 417                 goto out;
 418
 419         if (!delayed_work_pending(&devfreq->work) &&
 420                         devfreq->profile->polling_ms)
 421                 queue_delayed_work(devfreq_wq, &devfreq->work,
 422                         msecs_to_jiffies(devfreq->profile->polling_ms));
 423
 424         devfreq->last_stat_updated = jiffies;
 425         devfreq->stop_polling = false;
 426
 427         if (devfreq->profile->get_cur_freq &&
 428                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 429                 devfreq->previous_freq = freq;
 430
 431 out:
 432         mutex_unlock(&devfreq->lock);
 433 }
 434 EXPORT_SYMBOL(devfreq_monitor_resume);
 435
 436 /**
 437  * devfreq_interval_update() - Update device devfreq monitoring interval
 438  * @devfreq:    the devfreq instance.
 439  * @delay:      new polling interval to be set.
 440  *
 441  * Helper function to set new load monitoring polling interval. Function
 442  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 443  */
 444 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 445 {
 446         unsigned int cur_delay = devfreq->profile->polling_ms;
 447         unsigned int new_delay = *delay;
 448
 449         mutex_lock(&devfreq->lock);
 450         devfreq->profile->polling_ms = new_delay;
 451
 452         if (devfreq->stop_polling)
 453                 goto out;
 454
 455         /* if new delay is zero, stop polling */
 456         if (!new_delay) {
 457                 mutex_unlock(&devfreq->lock);
 458                 cancel_delayed_work_sync(&devfreq->work);
 459                 return;
 460         }
 461
 462         /* if current delay is zero, start polling with new delay */
 463         if (!cur_delay) {
 464                 queue_delayed_work(devfreq_wq, &devfreq->work,
 465                         msecs_to_jiffies(devfreq->profile->polling_ms));
 466                 goto out;
 467         }
 468
 469         /* if current delay is greater than new delay, restart polling */
 470         if (cur_delay > new_delay) {
 471                 mutex_unlock(&devfreq->lock);
 472                 cancel_delayed_work_sync(&devfreq->work);
 473                 mutex_lock(&devfreq->lock);
 474                 if (!devfreq->stop_polling)
 475                         queue_delayed_work(devfreq_wq, &devfreq->work,
 476                               msecs_to_jiffies(devfreq->profile->polling_ms));
 477         }
 478 out:
 479         mutex_unlock(&devfreq->lock);
 480 }
 481 EXPORT_SYMBOL(devfreq_interval_update);
 482
 483 /**
 484  * devfreq_notifier_call() - Notify that the device frequency requirements
 485  *                         has been changed out of devfreq framework.
 486  * @nb:         the notifier_block (supposed to be devfreq->nb)
 487  * @type:       not used
 488  * @devp:       not used
 489  *
 490  * Called by a notifier that uses devfreq->nb.
 491  */
 492 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 493                                  void *devp)
 494 {
 495         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 496         int ret;
 497
 498         mutex_lock(&devfreq->lock);
 499
 500         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 501         if (!devfreq->scaling_min_freq) {
 502                 mutex_unlock(&devfreq->lock);
 503                 return -EINVAL;
 504         }
 505
 506         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 507         if (!devfreq->scaling_max_freq) {
 508                 mutex_unlock(&devfreq->lock);
 509                 return -EINVAL;
 510         }
 511
 512         ret = update_devfreq(devfreq);
 513         mutex_unlock(&devfreq->lock);
 514
 515         return ret;
 516 }
 517
 518 /**
 519  * devfreq_dev_release() - Callback for struct device to release the device.
 520  * @dev:        the devfreq device
 521  *
 522  * Remove devfreq from the list and release its resources.
 523  */
 524 static void devfreq_dev_release(struct device *dev)
 525 {
 526         struct devfreq *devfreq = to_devfreq(dev);
 527
 528         mutex_lock(&devfreq_list_lock);
 529         if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
 530                 mutex_unlock(&devfreq_list_lock);
 531                 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
 532                 return;
 533         }
 534         list_del(&devfreq->node);
 535         mutex_unlock(&devfreq_list_lock);
 536
 537         if (devfreq->governor)
 538                 devfreq->governor->event_handler(devfreq,
 539                                                  DEVFREQ_GOV_STOP, NULL);
 540
 541         if (devfreq->profile->exit)
 542                 devfreq->profile->exit(devfreq->dev.parent);
 543
 544         mutex_destroy(&devfreq->lock);
 545         kfree(devfreq);
 546 }
 547
 548 /**
 549  * devfreq_add_device() - Add devfreq feature to the device
 550  * @dev:        the device to add devfreq feature.
 551  * @profile:    device-specific profile to run devfreq.
 552  * @governor_name:      name of the policy to choose frequency.
 553  * @data:       private data for the governor. The devfreq framework does not
 554  *              touch this value.
 555  */
 556 struct devfreq *devfreq_add_device(struct device *dev,
 557                                    struct devfreq_dev_profile *profile,
 558                                    const char *governor_name,
 559                                    void *data)
 560 {
 561         struct devfreq *devfreq;
 562         struct devfreq_governor *governor;
 563         static atomic_t devfreq_no = ATOMIC_INIT(-1);
 564         int err = 0;
 565
 566         if (!dev || !profile || !governor_name) {
 567                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 568                 return ERR_PTR(-EINVAL);
 569         }
 570
 571         mutex_lock(&devfreq_list_lock);
 572         devfreq = find_device_devfreq(dev);
 573         mutex_unlock(&devfreq_list_lock);
 574         if (!IS_ERR(devfreq)) {
 575                 dev_err(dev, "%s: Unable to create devfreq for the device.\n",
 576                         __func__);
 577                 err = -EINVAL;
 578                 goto err_out;
 579         }
 580
 581         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 582         if (!devfreq) {
 583                 err = -ENOMEM;
 584                 goto err_out;
 585         }
 586
 587         mutex_init(&devfreq->lock);
 588         mutex_lock(&devfreq->lock);
 589         devfreq->dev.parent = dev;
 590         devfreq->dev.class = devfreq_class;
 591         devfreq->dev.release = devfreq_dev_release;
 592         devfreq->profile = profile;
 593         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 594         devfreq->previous_freq = profile->initial_freq;
 595         devfreq->last_status.current_frequency = profile->initial_freq;
 596         devfreq->data = data;
 597         devfreq->nb.notifier_call = devfreq_notifier_call;
 598
 599         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 600                 mutex_unlock(&devfreq->lock);
 601                 err = set_freq_table(devfreq);
 602                 if (err < 0)
 603                         goto err_out;
 604                 mutex_lock(&devfreq->lock);
 605         }
 606
 607         devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 608         if (!devfreq->scaling_min_freq) {
 609                 mutex_unlock(&devfreq->lock);
 610                 err = -EINVAL;
 611                 goto err_dev;
 612         }
 613         devfreq->min_freq = devfreq->scaling_min_freq;
 614
 615         devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 616         if (!devfreq->scaling_max_freq) {
 617                 mutex_unlock(&devfreq->lock);
 618                 err = -EINVAL;
 619                 goto err_dev;
 620         }
 621         devfreq->max_freq = devfreq->scaling_max_freq;
 622
 623         dev_set_name(&devfreq->dev, "devfreq%d",
 624                                 atomic_inc_return(&devfreq_no));
 625         err = device_register(&devfreq->dev);
 626         if (err) {
 627                 mutex_unlock(&devfreq->lock);
 628                 put_device(&devfreq->dev);
 629                 goto err_out;
 630         }
 631
 632         devfreq->trans_table =
 633                 devm_kzalloc(&devfreq->dev,
 634                              array3_size(sizeof(unsigned int),
 635                                          devfreq->profile->max_state,
 636                                          devfreq->profile->max_state),
 637                              GFP_KERNEL);
 638         devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
 639                                                 devfreq->profile->max_state,
 640                                                 sizeof(unsigned long),
 641                                                 GFP_KERNEL);
 642         devfreq->last_stat_updated = jiffies;
 643
 644         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 645
 646         mutex_unlock(&devfreq->lock);
 647
 648         mutex_lock(&devfreq_list_lock);
 649         list_add(&devfreq->node, &devfreq_list);
 650
 651         governor = find_devfreq_governor(devfreq->governor_name);
 652         if (IS_ERR(governor)) {
 653                 dev_err(dev, "%s: Unable to find governor for the device\n",
 654                         __func__);
 655                 err = PTR_ERR(governor);
 656                 goto err_init;
 657         }
 658
 659         devfreq->governor = governor;
 660         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 661                                                 NULL);
 662         if (err) {
 663                 dev_err(dev, "%s: Unable to start governor for the device\n",
 664                         __func__);
 665                 goto err_init;
 666         }
 667         mutex_unlock(&devfreq_list_lock);
 668
 669         return devfreq;
 670
 671 err_init:
 672         list_del(&devfreq->node);
 673         mutex_unlock(&devfreq_list_lock);
 674
 675         device_unregister(&devfreq->dev);
 676         devfreq = NULL;
 677 err_dev:
 678         if (devfreq)
 679                 kfree(devfreq);
 680 err_out:
 681         return ERR_PTR(err);
 682 }
 683 EXPORT_SYMBOL(devfreq_add_device);
 684
 685 /**
 686  * devfreq_remove_device() - Remove devfreq feature from a device.
 687  * @devfreq:    the devfreq instance to be removed
 688  *
 689  * The opposite of devfreq_add_device().
 690  */
 691 int devfreq_remove_device(struct devfreq *devfreq)
 692 {
 693         if (!devfreq)
 694                 return -EINVAL;
 695
 696         device_unregister(&devfreq->dev);
 697
 698         return 0;
 699 }
 700 EXPORT_SYMBOL(devfreq_remove_device);
 701
 702 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 703 {
 704         struct devfreq **r = res;
 705
 706         if (WARN_ON(!r || !*r))
 707                 return 0;
 708
 709         return *r == data;
 710 }
 711
 712 static void devm_devfreq_dev_release(struct device *dev, void *res)
 713 {
 714         devfreq_remove_device(*(struct devfreq **)res);
 715 }
 716
 717 /**
 718  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 719  * @dev:        the device to add devfreq feature.
 720  * @profile:    device-specific profile to run devfreq.
 721  * @governor_name:      name of the policy to choose frequency.
 722  * @data:       private data for the governor. The devfreq framework does not
 723  *              touch this value.
 724  *
 725  * This function manages automatically the memory of devfreq device using device
 726  * resource management and simplify the free operation for memory of devfreq
 727  * device.
 728  */
 729 struct devfreq *devm_devfreq_add_device(struct device *dev,
 730                                         struct devfreq_dev_profile *profile,
 731                                         const char *governor_name,
 732                                         void *data)
 733 {
 734         struct devfreq **ptr, *devfreq;
 735
 736         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 737         if (!ptr)
 738                 return ERR_PTR(-ENOMEM);
 739
 740         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 741         if (IS_ERR(devfreq)) {
 742                 devres_free(ptr);
 743                 return devfreq;
 744         }
 745
 746         *ptr = devfreq;
 747         devres_add(dev, ptr);
 748
 749         return devfreq;
 750 }
 751 EXPORT_SYMBOL(devm_devfreq_add_device);
 752
 753 #ifdef CONFIG_OF
 754 /*
 755  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 756  * @dev - instance to the given device
 757  * @index - index into list of devfreq
 758  *
 759  * return the instance of devfreq device
 760  */
 761 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 762 {
 763         struct device_node *node;
 764         struct devfreq *devfreq;
 765
 766         if (!dev)
 767                 return ERR_PTR(-EINVAL);
 768
 769         if (!dev->of_node)
 770                 return ERR_PTR(-EINVAL);
 771
 772         node = of_parse_phandle(dev->of_node, "devfreq", index);
 773         if (!node)
 774                 return ERR_PTR(-ENODEV);
 775
 776         mutex_lock(&devfreq_list_lock);
 777         list_for_each_entry(devfreq, &devfreq_list, node) {
 778                 if (devfreq->dev.parent
 779                         && devfreq->dev.parent->of_node == node) {
 780                         mutex_unlock(&devfreq_list_lock);
 781                         of_node_put(node);
 782                         return devfreq;
 783                 }
 784         }
 785         mutex_unlock(&devfreq_list_lock);
 786         of_node_put(node);
 787
 788         return ERR_PTR(-EPROBE_DEFER);
 789 }
 790 #else
 791 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 792 {
 793         return ERR_PTR(-ENODEV);
 794 }
 795 #endif /* CONFIG_OF */
 796 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 797
 798 /**
 799  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 800  * @dev:        the device to add devfreq feature.
 801  * @devfreq:    the devfreq instance to be removed
 802  */
 803 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 804 {
 805         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 806                                devm_devfreq_dev_match, devfreq));
 807 }
 808 EXPORT_SYMBOL(devm_devfreq_remove_device);
 809
 810 /**
 811  * devfreq_suspend_device() - Suspend devfreq of a device.
 812  * @devfreq: the devfreq instance to be suspended
 813  *
 814  * This function is intended to be called by the pm callbacks
 815  * (e.g., runtime_suspend, suspend) of the device driver that
 816  * holds the devfreq.
 817  */
 818 int devfreq_suspend_device(struct devfreq *devfreq)
 819 {
 820         if (!devfreq)
 821                 return -EINVAL;
 822
 823         if (!devfreq->governor)
 824                 return 0;
 825
 826         return devfreq->governor->event_handler(devfreq,
 827                                 DEVFREQ_GOV_SUSPEND, NULL);
 828 }
 829 EXPORT_SYMBOL(devfreq_suspend_device);
 830
 831 /**
 832  * devfreq_resume_device() - Resume devfreq of a device.
 833  * @devfreq: the devfreq instance to be resumed
 834  *
 835  * This function is intended to be called by the pm callbacks
 836  * (e.g., runtime_resume, resume) of the device driver that
 837  * holds the devfreq.
 838  */
 839 int devfreq_resume_device(struct devfreq *devfreq)
 840 {
 841         if (!devfreq)
 842                 return -EINVAL;
 843
 844         if (!devfreq->governor)
 845                 return 0;
 846
 847         return devfreq->governor->event_handler(devfreq,
 848                                 DEVFREQ_GOV_RESUME, NULL);
 849 }
 850 EXPORT_SYMBOL(devfreq_resume_device);
 851
 852 /**
 853  * devfreq_add_governor() - Add devfreq governor
 854  * @governor:   the devfreq governor to be added
 855  */
 856 int devfreq_add_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 already registered\n", __func__,
 871                        g->name);
 872                 err = -EINVAL;
 873                 goto err_out;
 874         }
 875
 876         list_add(&governor->node, &devfreq_governor_list);
 877
 878         list_for_each_entry(devfreq, &devfreq_list, node) {
 879                 int ret = 0;
 880                 struct device *dev = devfreq->dev.parent;
 881
 882                 if (!strncmp(devfreq->governor_name, governor->name,
 883                              DEVFREQ_NAME_LEN)) {
 884                         /* The following should never occur */
 885                         if (devfreq->governor) {
 886                                 dev_warn(dev,
 887                                          "%s: Governor %s already present\n",
 888                                          __func__, devfreq->governor->name);
 889                                 ret = devfreq->governor->event_handler(devfreq,
 890                                                         DEVFREQ_GOV_STOP, NULL);
 891                                 if (ret) {
 892                                         dev_warn(dev,
 893                                                  "%s: Governor %s stop = %d\n",
 894                                                  __func__,
 895                                                  devfreq->governor->name, ret);
 896                                 }
 897                                 /* Fall through */
 898                         }
 899                         devfreq->governor = governor;
 900                         ret = devfreq->governor->event_handler(devfreq,
 901                                                 DEVFREQ_GOV_START, NULL);
 902                         if (ret) {
 903                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 904                                          __func__, devfreq->governor->name,
 905                                          ret);
 906                         }
 907                 }
 908         }
 909
 910 err_out:
 911         mutex_unlock(&devfreq_list_lock);
 912
 913         return err;
 914 }
 915 EXPORT_SYMBOL(devfreq_add_governor);
 916
 917 /**
 918  * devfreq_remove_governor() - Remove devfreq feature from a device.
 919  * @governor:   the devfreq governor to be removed
 920  */
 921 int devfreq_remove_governor(struct devfreq_governor *governor)
 922 {
 923         struct devfreq_governor *g;
 924         struct devfreq *devfreq;
 925         int err = 0;
 926
 927         if (!governor) {
 928                 pr_err("%s: Invalid parameters.\n", __func__);
 929                 return -EINVAL;
 930         }
 931
 932         mutex_lock(&devfreq_list_lock);
 933         g = find_devfreq_governor(governor->name);
 934         if (IS_ERR(g)) {
 935                 pr_err("%s: governor %s not registered\n", __func__,
 936                        governor->name);
 937                 err = PTR_ERR(g);
 938                 goto err_out;
 939         }
 940         list_for_each_entry(devfreq, &devfreq_list, node) {
 941                 int ret;
 942                 struct device *dev = devfreq->dev.parent;
 943
 944                 if (!strncmp(devfreq->governor_name, governor->name,
 945                              DEVFREQ_NAME_LEN)) {
 946                         /* we should have a devfreq governor! */
 947                         if (!devfreq->governor) {
 948                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 949                                          __func__, governor->name);
 950                                 continue;
 951                                 /* Fall through */
 952                         }
 953                         ret = devfreq->governor->event_handler(devfreq,
 954                                                 DEVFREQ_GOV_STOP, NULL);
 955                         if (ret) {
 956                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 957                                          __func__, devfreq->governor->name,
 958                                          ret);
 959                         }
 960                         devfreq->governor = NULL;
 961                 }
 962         }
 963
 964         list_del(&governor->node);
 965 err_out:
 966         mutex_unlock(&devfreq_list_lock);
 967
 968         return err;
 969 }
 970 EXPORT_SYMBOL(devfreq_remove_governor);
 971
 972 static ssize_t governor_show(struct device *dev,
 973                              struct device_attribute *attr, char *buf)
 974 {
 975         if (!to_devfreq(dev)->governor)
 976                 return -EINVAL;
 977
 978         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 979 }
 980
 981 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 982                               const char *buf, size_t count)
 983 {
 984         struct devfreq *df = to_devfreq(dev);
 985         int ret;
 986         char str_governor[DEVFREQ_NAME_LEN + 1];
 987         struct devfreq_governor *governor;
 988
 989         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 990         if (ret != 1)
 991                 return -EINVAL;
 992
 993         mutex_lock(&devfreq_list_lock);
 994         governor = find_devfreq_governor(str_governor);
 995         if (IS_ERR(governor)) {
 996                 ret = PTR_ERR(governor);
 997                 goto out;
 998         }
 999         if (df->governor == governor) {
1000                 ret = 0;
1001                 goto out;
1002         } else if ((df->governor && df->governor->immutable) ||
1003                                         governor->immutable) {
1004                 ret = -EINVAL;
1005                 goto out;
1006         }
1007
1008         if (df->governor) {
1009                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1010                 if (ret) {
1011                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1012                                  __func__, df->governor->name, ret);
1013                         goto out;
1014                 }
1015         }
1016         df->governor = governor;
1017         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1018         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1019         if (ret)
1020                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1021                          __func__, df->governor->name, ret);
1022 out:
1023         mutex_unlock(&devfreq_list_lock);
1024
1025         if (!ret)
1026                 ret = count;
1027         return ret;
1028 }
1029 static DEVICE_ATTR_RW(governor);
1030
1031 static ssize_t available_governors_show(struct device *d,
1032                                         struct device_attribute *attr,
1033                                         char *buf)
1034 {
1035         struct devfreq *df = to_devfreq(d);
1036         ssize_t count = 0;
1037
1038         mutex_lock(&devfreq_list_lock);
1039
1040         /*
1041          * The devfreq with immutable governor (e.g., passive) shows
1042          * only own governor.
1043          */
1044         if (df->governor->immutable) {
1045                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1046                                    "%s ", df->governor_name);
1047         /*
1048          * The devfreq device shows the registered governor except for
1049          * immutable governors such as passive governor .
1050          */
1051         } else {
1052                 struct devfreq_governor *governor;
1053
1054                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1055                         if (governor->immutable)
1056                                 continue;
1057                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1058                                            "%s ", governor->name);
1059                 }
1060         }
1061
1062         mutex_unlock(&devfreq_list_lock);
1063
1064         /* Truncate the trailing space */
1065         if (count)
1066                 count--;
1067
1068         count += sprintf(&buf[count], "\n");
1069
1070         return count;
1071 }
1072 static DEVICE_ATTR_RO(available_governors);
1073
1074 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1075                              char *buf)
1076 {
1077         unsigned long freq;
1078         struct devfreq *devfreq = to_devfreq(dev);
1079
1080         if (devfreq->profile->get_cur_freq &&
1081                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1082                 return sprintf(buf, "%lu\n", freq);
1083
1084         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1085 }
1086 static DEVICE_ATTR_RO(cur_freq);
1087
1088 static ssize_t target_freq_show(struct device *dev,
1089                                 struct device_attribute *attr, char *buf)
1090 {
1091         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1092 }
1093 static DEVICE_ATTR_RO(target_freq);
1094
1095 static ssize_t polling_interval_show(struct device *dev,
1096                                      struct device_attribute *attr, char *buf)
1097 {
1098         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1099 }
1100
1101 static ssize_t polling_interval_store(struct device *dev,
1102                                       struct device_attribute *attr,
1103                                       const char *buf, size_t count)
1104 {
1105         struct devfreq *df = to_devfreq(dev);
1106         unsigned int value;
1107         int ret;
1108
1109         if (!df->governor)
1110                 return -EINVAL;
1111
1112         ret = sscanf(buf, "%u", &value);
1113         if (ret != 1)
1114                 return -EINVAL;
1115
1116         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1117         ret = count;
1118
1119         return ret;
1120 }
1121 static DEVICE_ATTR_RW(polling_interval);
1122
1123 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1124                               const char *buf, size_t count)
1125 {
1126         struct devfreq *df = to_devfreq(dev);
1127         unsigned long value;
1128         int ret;
1129         unsigned long max;
1130
1131         ret = sscanf(buf, "%lu", &value);
1132         if (ret != 1)
1133                 return -EINVAL;
1134
1135         mutex_lock(&df->lock);
1136         max = df->max_freq;
1137         if (value && max && value > max) {
1138                 ret = -EINVAL;
1139                 goto unlock;
1140         }
1141
1142         df->min_freq = value;
1143         update_devfreq(df);
1144         ret = count;
1145 unlock:
1146         mutex_unlock(&df->lock);
1147         return ret;
1148 }
1149
1150 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1151                              char *buf)
1152 {
1153         struct devfreq *df = to_devfreq(dev);
1154
1155         return sprintf(buf, "%lu\n", MAX(df->scaling_min_freq, df->min_freq));
1156 }
1157
1158 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1159                               const char *buf, size_t count)
1160 {
1161         struct devfreq *df = to_devfreq(dev);
1162         unsigned long value;
1163         int ret;
1164         unsigned long min;
1165
1166         ret = sscanf(buf, "%lu", &value);
1167         if (ret != 1)
1168                 return -EINVAL;
1169
1170         mutex_lock(&df->lock);
1171         min = df->min_freq;
1172         if (value && min && value < min) {
1173                 ret = -EINVAL;
1174                 goto unlock;
1175         }
1176
1177         df->max_freq = value;
1178         update_devfreq(df);
1179         ret = count;
1180 unlock:
1181         mutex_unlock(&df->lock);
1182         return ret;
1183 }
1184 static DEVICE_ATTR_RW(min_freq);
1185
1186 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1187                              char *buf)
1188 {
1189         struct devfreq *df = to_devfreq(dev);
1190
1191         return sprintf(buf, "%lu\n", MIN(df->scaling_max_freq, df->max_freq));
1192 }
1193 static DEVICE_ATTR_RW(max_freq);
1194
1195 static ssize_t available_frequencies_show(struct device *d,
1196                                           struct device_attribute *attr,
1197                                           char *buf)
1198 {
1199         struct devfreq *df = to_devfreq(d);
1200         ssize_t count = 0;
1201         int i;
1202
1203         mutex_lock(&df->lock);
1204
1205         for (i = 0; i < df->profile->max_state; i++)
1206                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1207                                 "%lu ", df->profile->freq_table[i]);
1208
1209         mutex_unlock(&df->lock);
1210         /* Truncate the trailing space */
1211         if (count)
1212                 count--;
1213
1214         count += sprintf(&buf[count], "\n");
1215
1216         return count;
1217 }
1218 static DEVICE_ATTR_RO(available_frequencies);
1219
1220 static ssize_t trans_stat_show(struct device *dev,
1221                                struct device_attribute *attr, char *buf)
1222 {
1223         struct devfreq *devfreq = to_devfreq(dev);
1224         ssize_t len;
1225         int i, j;
1226         unsigned int max_state = devfreq->profile->max_state;
1227
1228         if (!devfreq->stop_polling &&
1229                         devfreq_update_status(devfreq, devfreq->previous_freq))
1230                 return 0;
1231         if (max_state == 0)
1232                 return sprintf(buf, "Not Supported.\n");
1233
1234         len = sprintf(buf, "     From  :   To\n");
1235         len += sprintf(buf + len, "           :");
1236         for (i = 0; i < max_state; i++)
1237                 len += sprintf(buf + len, "%10lu",
1238                                 devfreq->profile->freq_table[i]);
1239
1240         len += sprintf(buf + len, "   time(ms)\n");
1241
1242         for (i = 0; i < max_state; i++) {
1243                 if (devfreq->profile->freq_table[i]
1244                                         == devfreq->previous_freq) {
1245                         len += sprintf(buf + len, "*");
1246                 } else {
1247                         len += sprintf(buf + len, " ");
1248                 }
1249                 len += sprintf(buf + len, "%10lu:",
1250                                 devfreq->profile->freq_table[i]);
1251                 for (j = 0; j < max_state; j++)
1252                         len += sprintf(buf + len, "%10u",
1253                                 devfreq->trans_table[(i * max_state) + j]);
1254                 len += sprintf(buf + len, "%10u\n",
1255                         jiffies_to_msecs(devfreq->time_in_state[i]));
1256         }
1257
1258         len += sprintf(buf + len, "Total transition : %u\n",
1259                                         devfreq->total_trans);
1260         return len;
1261 }
1262 static DEVICE_ATTR_RO(trans_stat);
1263
1264 static struct attribute *devfreq_attrs[] = {
1265         &dev_attr_governor.attr,
1266         &dev_attr_available_governors.attr,
1267         &dev_attr_cur_freq.attr,
1268         &dev_attr_available_frequencies.attr,
1269         &dev_attr_target_freq.attr,
1270         &dev_attr_polling_interval.attr,
1271         &dev_attr_min_freq.attr,
1272         &dev_attr_max_freq.attr,
1273         &dev_attr_trans_stat.attr,
1274         NULL,
1275 };
1276 ATTRIBUTE_GROUPS(devfreq);
1277
1278 static int __init devfreq_init(void)
1279 {
1280         devfreq_class = class_create(THIS_MODULE, "devfreq");
1281         if (IS_ERR(devfreq_class)) {
1282                 pr_err("%s: couldn't create class\n", __FILE__);
1283                 return PTR_ERR(devfreq_class);
1284         }
1285
1286         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1287         if (!devfreq_wq) {
1288                 class_destroy(devfreq_class);
1289                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1290                 return -ENOMEM;
1291         }
1292         devfreq_class->dev_groups = devfreq_groups;
1293
1294         return 0;
1295 }
1296 subsys_initcall(devfreq_init);
1297
1298 /*
1299  * The following are helper functions for devfreq user device drivers with
1300  * OPP framework.
1301  */
1302
1303 /**
1304  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1305  *                           freq value given to target callback.
1306  * @dev:        The devfreq user device. (parent of devfreq)
1307  * @freq:       The frequency given to target function
1308  * @flags:      Flags handed from devfreq framework.
1309  *
1310  * The callers are required to call dev_pm_opp_put() for the returned OPP after
1311  * use.
1312  */
1313 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1314                                            unsigned long *freq,
1315                                            u32 flags)
1316 {
1317         struct dev_pm_opp *opp;
1318
1319         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1320                 /* The freq is an upper bound. opp should be lower */
1321                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1322
1323                 /* If not available, use the closest opp */
1324                 if (opp == ERR_PTR(-ERANGE))
1325                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1326         } else {
1327                 /* The freq is an lower bound. opp should be higher */
1328                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1329
1330                 /* If not available, use the closest opp */
1331                 if (opp == ERR_PTR(-ERANGE))
1332                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1333         }
1334
1335         return opp;
1336 }
1337 EXPORT_SYMBOL(devfreq_recommended_opp);
1338
1339 /**
1340  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1341  *                                 for any changes in the OPP availability
1342  *                                 changes
1343  * @dev:        The devfreq user device. (parent of devfreq)
1344  * @devfreq:    The devfreq object.
1345  */
1346 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1347 {
1348         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1349 }
1350 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1351
1352 /**
1353  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1354  *                                   notified for any changes in the OPP
1355  *                                   availability changes anymore.
1356  * @dev:        The devfreq user device. (parent of devfreq)
1357  * @devfreq:    The devfreq object.
1358  *
1359  * At exit() callback of devfreq_dev_profile, this must be included if
1360  * devfreq_recommended_opp is used.
1361  */
1362 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1363 {
1364         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1365 }
1366 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1367
1368 static void devm_devfreq_opp_release(struct device *dev, void *res)
1369 {
1370         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1371 }
1372
1373 /**
1374  * devm_ devfreq_register_opp_notifier()
1375  *              - Resource-managed devfreq_register_opp_notifier()
1376  * @dev:        The devfreq user device. (parent of devfreq)
1377  * @devfreq:    The devfreq object.
1378  */
1379 int devm_devfreq_register_opp_notifier(struct device *dev,
1380                                        struct devfreq *devfreq)
1381 {
1382         struct devfreq **ptr;
1383         int ret;
1384
1385         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1386         if (!ptr)
1387                 return -ENOMEM;
1388
1389         ret = devfreq_register_opp_notifier(dev, devfreq);
1390         if (ret) {
1391                 devres_free(ptr);
1392                 return ret;
1393         }
1394
1395         *ptr = devfreq;
1396         devres_add(dev, ptr);
1397
1398         return 0;
1399 }
1400 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1401
1402 /**
1403  * devm_devfreq_unregister_opp_notifier()
1404  *              - Resource-managed devfreq_unregister_opp_notifier()
1405  * @dev:        The devfreq user device. (parent of devfreq)
1406  * @devfreq:    The devfreq object.
1407  */
1408 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1409                                          struct devfreq *devfreq)
1410 {
1411         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1412                                devm_devfreq_dev_match, devfreq));
1413 }
1414 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1415
1416 /**
1417  * devfreq_register_notifier() - Register a driver with devfreq
1418  * @devfreq:    The devfreq object.
1419  * @nb:         The notifier block to register.
1420  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1421  */
1422 int devfreq_register_notifier(struct devfreq *devfreq,
1423                                 struct notifier_block *nb,
1424                                 unsigned int list)
1425 {
1426         int ret = 0;
1427
1428         if (!devfreq)
1429                 return -EINVAL;
1430
1431         switch (list) {
1432         case DEVFREQ_TRANSITION_NOTIFIER:
1433                 ret = srcu_notifier_chain_register(
1434                                 &devfreq->transition_notifier_list, nb);
1435                 break;
1436         default:
1437                 ret = -EINVAL;
1438         }
1439
1440         return ret;
1441 }
1442 EXPORT_SYMBOL(devfreq_register_notifier);
1443
1444 /*
1445  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1446  * @devfreq:    The devfreq object.
1447  * @nb:         The notifier block to be unregistered.
1448  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1449  */
1450 int devfreq_unregister_notifier(struct devfreq *devfreq,
1451                                 struct notifier_block *nb,
1452                                 unsigned int list)
1453 {
1454         int ret = 0;
1455
1456         if (!devfreq)
1457                 return -EINVAL;
1458
1459         switch (list) {
1460         case DEVFREQ_TRANSITION_NOTIFIER:
1461                 ret = srcu_notifier_chain_unregister(
1462                                 &devfreq->transition_notifier_list, nb);
1463                 break;
1464         default:
1465                 ret = -EINVAL;
1466         }
1467
1468         return ret;
1469 }
1470 EXPORT_SYMBOL(devfreq_unregister_notifier);
1471
1472 struct devfreq_notifier_devres {
1473         struct devfreq *devfreq;
1474         struct notifier_block *nb;
1475         unsigned int list;
1476 };
1477
1478 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1479 {
1480         struct devfreq_notifier_devres *this = res;
1481
1482         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1483 }
1484
1485 /**
1486  * devm_devfreq_register_notifier()
1487         - Resource-managed devfreq_register_notifier()
1488  * @dev:        The devfreq user device. (parent of devfreq)
1489  * @devfreq:    The devfreq object.
1490  * @nb:         The notifier block to be unregistered.
1491  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1492  */
1493 int devm_devfreq_register_notifier(struct device *dev,
1494                                 struct devfreq *devfreq,
1495                                 struct notifier_block *nb,
1496                                 unsigned int list)
1497 {
1498         struct devfreq_notifier_devres *ptr;
1499         int ret;
1500
1501         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1502                                 GFP_KERNEL);
1503         if (!ptr)
1504                 return -ENOMEM;
1505
1506         ret = devfreq_register_notifier(devfreq, nb, list);
1507         if (ret) {
1508                 devres_free(ptr);
1509                 return ret;
1510         }
1511
1512         ptr->devfreq = devfreq;
1513         ptr->nb = nb;
1514         ptr->list = list;
1515         devres_add(dev, ptr);
1516
1517         return 0;
1518 }
1519 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1520
1521 /**
1522  * devm_devfreq_unregister_notifier()
1523         - Resource-managed devfreq_unregister_notifier()
1524  * @dev:        The devfreq user device. (parent of devfreq)
1525  * @devfreq:    The devfreq object.
1526  * @nb:         The notifier block to be unregistered.
1527  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1528  */
1529 void devm_devfreq_unregister_notifier(struct device *dev,
1530                                 struct devfreq *devfreq,
1531                                 struct notifier_block *nb,
1532                                 unsigned int list)
1533 {
1534         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1535                                devm_devfreq_dev_match, devfreq));
1536 }
1537 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);