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 #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->min_freq = find_available_min_freq(devfreq);
 608         if (!devfreq->min_freq) {
 609                 mutex_unlock(&devfreq->lock);
 610                 err = -EINVAL;
 611                 goto err_dev;
 612         }
 613         devfreq->scaling_min_freq = devfreq->min_freq;
 614
 615         devfreq->max_freq = find_available_max_freq(devfreq);
 616         if (!devfreq->max_freq) {
 617                 mutex_unlock(&devfreq->lock);
 618                 err = -EINVAL;
 619                 goto err_dev;
 620         }
 621         devfreq->scaling_max_freq = devfreq->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                 goto err_dev;
 629         }
 630
 631         devfreq->trans_table =  devm_kzalloc(&devfreq->dev,
 632                                                 sizeof(unsigned int) *
 633                                                 devfreq->profile->max_state *
 634                                                 devfreq->profile->max_state,
 635                                                 GFP_KERNEL);
 636         devfreq->time_in_state = devm_kzalloc(&devfreq->dev,
 637                                                 sizeof(unsigned long) *
 638                                                 devfreq->profile->max_state,
 639                                                 GFP_KERNEL);
 640         devfreq->last_stat_updated = jiffies;
 641
 642         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 643
 644         mutex_unlock(&devfreq->lock);
 645
 646         mutex_lock(&devfreq_list_lock);
 647         list_add(&devfreq->node, &devfreq_list);
 648
 649         governor = find_devfreq_governor(devfreq->governor_name);
 650         if (IS_ERR(governor)) {
 651                 dev_err(dev, "%s: Unable to find governor for the device\n",
 652                         __func__);
 653                 err = PTR_ERR(governor);
 654                 goto err_init;
 655         }
 656
 657         devfreq->governor = governor;
 658         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 659                                                 NULL);
 660         if (err) {
 661                 dev_err(dev, "%s: Unable to start governor for the device\n",
 662                         __func__);
 663                 goto err_init;
 664         }
 665         mutex_unlock(&devfreq_list_lock);
 666
 667         return devfreq;
 668
 669 err_init:
 670         list_del(&devfreq->node);
 671         mutex_unlock(&devfreq_list_lock);
 672
 673         device_unregister(&devfreq->dev);
 674 err_dev:
 675         if (devfreq)
 676                 kfree(devfreq);
 677 err_out:
 678         return ERR_PTR(err);
 679 }
 680 EXPORT_SYMBOL(devfreq_add_device);
 681
 682 /**
 683  * devfreq_remove_device() - Remove devfreq feature from a device.
 684  * @devfreq:    the devfreq instance to be removed
 685  *
 686  * The opposite of devfreq_add_device().
 687  */
 688 int devfreq_remove_device(struct devfreq *devfreq)
 689 {
 690         if (!devfreq)
 691                 return -EINVAL;
 692
 693         device_unregister(&devfreq->dev);
 694
 695         return 0;
 696 }
 697 EXPORT_SYMBOL(devfreq_remove_device);
 698
 699 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 700 {
 701         struct devfreq **r = res;
 702
 703         if (WARN_ON(!r || !*r))
 704                 return 0;
 705
 706         return *r == data;
 707 }
 708
 709 static void devm_devfreq_dev_release(struct device *dev, void *res)
 710 {
 711         devfreq_remove_device(*(struct devfreq **)res);
 712 }
 713
 714 /**
 715  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 716  * @dev:        the device to add devfreq feature.
 717  * @profile:    device-specific profile to run devfreq.
 718  * @governor_name:      name of the policy to choose frequency.
 719  * @data:       private data for the governor. The devfreq framework does not
 720  *              touch this value.
 721  *
 722  * This function manages automatically the memory of devfreq device using device
 723  * resource management and simplify the free operation for memory of devfreq
 724  * device.
 725  */
 726 struct devfreq *devm_devfreq_add_device(struct device *dev,
 727                                         struct devfreq_dev_profile *profile,
 728                                         const char *governor_name,
 729                                         void *data)
 730 {
 731         struct devfreq **ptr, *devfreq;
 732
 733         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 734         if (!ptr)
 735                 return ERR_PTR(-ENOMEM);
 736
 737         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 738         if (IS_ERR(devfreq)) {
 739                 devres_free(ptr);
 740                 return ERR_PTR(-ENOMEM);
 741         }
 742
 743         *ptr = devfreq;
 744         devres_add(dev, ptr);
 745
 746         return devfreq;
 747 }
 748 EXPORT_SYMBOL(devm_devfreq_add_device);
 749
 750 #ifdef CONFIG_OF
 751 /*
 752  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 753  * @dev - instance to the given device
 754  * @index - index into list of devfreq
 755  *
 756  * return the instance of devfreq device
 757  */
 758 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 759 {
 760         struct device_node *node;
 761         struct devfreq *devfreq;
 762
 763         if (!dev)
 764                 return ERR_PTR(-EINVAL);
 765
 766         if (!dev->of_node)
 767                 return ERR_PTR(-EINVAL);
 768
 769         node = of_parse_phandle(dev->of_node, "devfreq", index);
 770         if (!node)
 771                 return ERR_PTR(-ENODEV);
 772
 773         mutex_lock(&devfreq_list_lock);
 774         list_for_each_entry(devfreq, &devfreq_list, node) {
 775                 if (devfreq->dev.parent
 776                         && devfreq->dev.parent->of_node == node) {
 777                         mutex_unlock(&devfreq_list_lock);
 778                         of_node_put(node);
 779                         return devfreq;
 780                 }
 781         }
 782         mutex_unlock(&devfreq_list_lock);
 783         of_node_put(node);
 784
 785         return ERR_PTR(-EPROBE_DEFER);
 786 }
 787 #else
 788 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 789 {
 790         return ERR_PTR(-ENODEV);
 791 }
 792 #endif /* CONFIG_OF */
 793 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 794
 795 /**
 796  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 797  * @dev:        the device to add devfreq feature.
 798  * @devfreq:    the devfreq instance to be removed
 799  */
 800 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 801 {
 802         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 803                                devm_devfreq_dev_match, devfreq));
 804 }
 805 EXPORT_SYMBOL(devm_devfreq_remove_device);
 806
 807 /**
 808  * devfreq_suspend_device() - Suspend devfreq of a device.
 809  * @devfreq: the devfreq instance to be suspended
 810  *
 811  * This function is intended to be called by the pm callbacks
 812  * (e.g., runtime_suspend, suspend) of the device driver that
 813  * holds the devfreq.
 814  */
 815 int devfreq_suspend_device(struct devfreq *devfreq)
 816 {
 817         if (!devfreq)
 818                 return -EINVAL;
 819
 820         if (!devfreq->governor)
 821                 return 0;
 822
 823         return devfreq->governor->event_handler(devfreq,
 824                                 DEVFREQ_GOV_SUSPEND, NULL);
 825 }
 826 EXPORT_SYMBOL(devfreq_suspend_device);
 827
 828 /**
 829  * devfreq_resume_device() - Resume devfreq of a device.
 830  * @devfreq: the devfreq instance to be resumed
 831  *
 832  * This function is intended to be called by the pm callbacks
 833  * (e.g., runtime_resume, resume) of the device driver that
 834  * holds the devfreq.
 835  */
 836 int devfreq_resume_device(struct devfreq *devfreq)
 837 {
 838         if (!devfreq)
 839                 return -EINVAL;
 840
 841         if (!devfreq->governor)
 842                 return 0;
 843
 844         return devfreq->governor->event_handler(devfreq,
 845                                 DEVFREQ_GOV_RESUME, NULL);
 846 }
 847 EXPORT_SYMBOL(devfreq_resume_device);
 848
 849 /**
 850  * devfreq_add_governor() - Add devfreq governor
 851  * @governor:   the devfreq governor to be added
 852  */
 853 int devfreq_add_governor(struct devfreq_governor *governor)
 854 {
 855         struct devfreq_governor *g;
 856         struct devfreq *devfreq;
 857         int err = 0;
 858
 859         if (!governor) {
 860                 pr_err("%s: Invalid parameters.\n", __func__);
 861                 return -EINVAL;
 862         }
 863
 864         mutex_lock(&devfreq_list_lock);
 865         g = find_devfreq_governor(governor->name);
 866         if (!IS_ERR(g)) {
 867                 pr_err("%s: governor %s already registered\n", __func__,
 868                        g->name);
 869                 err = -EINVAL;
 870                 goto err_out;
 871         }
 872
 873         list_add(&governor->node, &devfreq_governor_list);
 874
 875         list_for_each_entry(devfreq, &devfreq_list, node) {
 876                 int ret = 0;
 877                 struct device *dev = devfreq->dev.parent;
 878
 879                 if (!strncmp(devfreq->governor_name, governor->name,
 880                              DEVFREQ_NAME_LEN)) {
 881                         /* The following should never occur */
 882                         if (devfreq->governor) {
 883                                 dev_warn(dev,
 884                                          "%s: Governor %s already present\n",
 885                                          __func__, devfreq->governor->name);
 886                                 ret = devfreq->governor->event_handler(devfreq,
 887                                                         DEVFREQ_GOV_STOP, NULL);
 888                                 if (ret) {
 889                                         dev_warn(dev,
 890                                                  "%s: Governor %s stop = %d\n",
 891                                                  __func__,
 892                                                  devfreq->governor->name, ret);
 893                                 }
 894                                 /* Fall through */
 895                         }
 896                         devfreq->governor = governor;
 897                         ret = devfreq->governor->event_handler(devfreq,
 898                                                 DEVFREQ_GOV_START, NULL);
 899                         if (ret) {
 900                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 901                                          __func__, devfreq->governor->name,
 902                                          ret);
 903                         }
 904                 }
 905         }
 906
 907 err_out:
 908         mutex_unlock(&devfreq_list_lock);
 909
 910         return err;
 911 }
 912 EXPORT_SYMBOL(devfreq_add_governor);
 913
 914 /**
 915  * devfreq_remove_governor() - Remove devfreq feature from a device.
 916  * @governor:   the devfreq governor to be removed
 917  */
 918 int devfreq_remove_governor(struct devfreq_governor *governor)
 919 {
 920         struct devfreq_governor *g;
 921         struct devfreq *devfreq;
 922         int err = 0;
 923
 924         if (!governor) {
 925                 pr_err("%s: Invalid parameters.\n", __func__);
 926                 return -EINVAL;
 927         }
 928
 929         mutex_lock(&devfreq_list_lock);
 930         g = find_devfreq_governor(governor->name);
 931         if (IS_ERR(g)) {
 932                 pr_err("%s: governor %s not registered\n", __func__,
 933                        governor->name);
 934                 err = PTR_ERR(g);
 935                 goto err_out;
 936         }
 937         list_for_each_entry(devfreq, &devfreq_list, node) {
 938                 int ret;
 939                 struct device *dev = devfreq->dev.parent;
 940
 941                 if (!strncmp(devfreq->governor_name, governor->name,
 942                              DEVFREQ_NAME_LEN)) {
 943                         /* we should have a devfreq governor! */
 944                         if (!devfreq->governor) {
 945                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 946                                          __func__, governor->name);
 947                                 continue;
 948                                 /* Fall through */
 949                         }
 950                         ret = devfreq->governor->event_handler(devfreq,
 951                                                 DEVFREQ_GOV_STOP, NULL);
 952                         if (ret) {
 953                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 954                                          __func__, devfreq->governor->name,
 955                                          ret);
 956                         }
 957                         devfreq->governor = NULL;
 958                 }
 959         }
 960
 961         list_del(&governor->node);
 962 err_out:
 963         mutex_unlock(&devfreq_list_lock);
 964
 965         return err;
 966 }
 967 EXPORT_SYMBOL(devfreq_remove_governor);
 968
 969 static ssize_t governor_show(struct device *dev,
 970                              struct device_attribute *attr, char *buf)
 971 {
 972         if (!to_devfreq(dev)->governor)
 973                 return -EINVAL;
 974
 975         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 976 }
 977
 978 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 979                               const char *buf, size_t count)
 980 {
 981         struct devfreq *df = to_devfreq(dev);
 982         int ret;
 983         char str_governor[DEVFREQ_NAME_LEN + 1];
 984         struct devfreq_governor *governor;
 985
 986         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 987         if (ret != 1)
 988                 return -EINVAL;
 989
 990         mutex_lock(&devfreq_list_lock);
 991         governor = find_devfreq_governor(str_governor);
 992         if (IS_ERR(governor)) {
 993                 ret = PTR_ERR(governor);
 994                 goto out;
 995         }
 996         if (df->governor == governor) {
 997                 ret = 0;
 998                 goto out;
 999         } else if (df->governor->immutable || governor->immutable) {
1000                 ret = -EINVAL;
1001                 goto out;
1002         }
1003
1004         if (df->governor) {
1005                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1006                 if (ret) {
1007                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1008                                  __func__, df->governor->name, ret);
1009                         goto out;
1010                 }
1011         }
1012         df->governor = governor;
1013         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1014         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1015         if (ret)
1016                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1017                          __func__, df->governor->name, ret);
1018 out:
1019         mutex_unlock(&devfreq_list_lock);
1020
1021         if (!ret)
1022                 ret = count;
1023         return ret;
1024 }
1025 static DEVICE_ATTR_RW(governor);
1026
1027 static ssize_t available_governors_show(struct device *d,
1028                                         struct device_attribute *attr,
1029                                         char *buf)
1030 {
1031         struct devfreq *df = to_devfreq(d);
1032         ssize_t count = 0;
1033
1034         mutex_lock(&devfreq_list_lock);
1035
1036         /*
1037          * The devfreq with immutable governor (e.g., passive) shows
1038          * only own governor.
1039          */
1040         if (df->governor->immutable) {
1041                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1042                                    "%s ", df->governor_name);
1043         /*
1044          * The devfreq device shows the registered governor except for
1045          * immutable governors such as passive governor .
1046          */
1047         } else {
1048                 struct devfreq_governor *governor;
1049
1050                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1051                         if (governor->immutable)
1052                                 continue;
1053                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1054                                            "%s ", governor->name);
1055                 }
1056         }
1057
1058         mutex_unlock(&devfreq_list_lock);
1059
1060         /* Truncate the trailing space */
1061         if (count)
1062                 count--;
1063
1064         count += sprintf(&buf[count], "\n");
1065
1066         return count;
1067 }
1068 static DEVICE_ATTR_RO(available_governors);
1069
1070 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1071                              char *buf)
1072 {
1073         unsigned long freq;
1074         struct devfreq *devfreq = to_devfreq(dev);
1075
1076         if (devfreq->profile->get_cur_freq &&
1077                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1078                 return sprintf(buf, "%lu\n", freq);
1079
1080         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1081 }
1082 static DEVICE_ATTR_RO(cur_freq);
1083
1084 static ssize_t target_freq_show(struct device *dev,
1085                                 struct device_attribute *attr, char *buf)
1086 {
1087         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1088 }
1089 static DEVICE_ATTR_RO(target_freq);
1090
1091 static ssize_t polling_interval_show(struct device *dev,
1092                                      struct device_attribute *attr, char *buf)
1093 {
1094         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1095 }
1096
1097 static ssize_t polling_interval_store(struct device *dev,
1098                                       struct device_attribute *attr,
1099                                       const char *buf, size_t count)
1100 {
1101         struct devfreq *df = to_devfreq(dev);
1102         unsigned int value;
1103         int ret;
1104
1105         if (!df->governor)
1106                 return -EINVAL;
1107
1108         ret = sscanf(buf, "%u", &value);
1109         if (ret != 1)
1110                 return -EINVAL;
1111
1112         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1113         ret = count;
1114
1115         return ret;
1116 }
1117 static DEVICE_ATTR_RW(polling_interval);
1118
1119 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1120                               const char *buf, size_t count)
1121 {
1122         struct devfreq *df = to_devfreq(dev);
1123         unsigned long value;
1124         int ret;
1125         unsigned long max;
1126
1127         ret = sscanf(buf, "%lu", &value);
1128         if (ret != 1)
1129                 return -EINVAL;
1130
1131         mutex_lock(&df->lock);
1132         max = df->max_freq;
1133         if (value && max && value > max) {
1134                 ret = -EINVAL;
1135                 goto unlock;
1136         }
1137
1138         df->min_freq = value;
1139         update_devfreq(df);
1140         ret = count;
1141 unlock:
1142         mutex_unlock(&df->lock);
1143         return ret;
1144 }
1145
1146 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1147                              char *buf)
1148 {
1149         struct devfreq *df = to_devfreq(dev);
1150
1151         return sprintf(buf, "%lu\n", MAX(df->scaling_min_freq, df->min_freq));
1152 }
1153
1154 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1155                               const char *buf, size_t count)
1156 {
1157         struct devfreq *df = to_devfreq(dev);
1158         unsigned long value;
1159         int ret;
1160         unsigned long min;
1161
1162         ret = sscanf(buf, "%lu", &value);
1163         if (ret != 1)
1164                 return -EINVAL;
1165
1166         mutex_lock(&df->lock);
1167         min = df->min_freq;
1168         if (value && min && value < min) {
1169                 ret = -EINVAL;
1170                 goto unlock;
1171         }
1172
1173         df->max_freq = value;
1174         update_devfreq(df);
1175         ret = count;
1176 unlock:
1177         mutex_unlock(&df->lock);
1178         return ret;
1179 }
1180 static DEVICE_ATTR_RW(min_freq);
1181
1182 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1183                              char *buf)
1184 {
1185         struct devfreq *df = to_devfreq(dev);
1186
1187         return sprintf(buf, "%lu\n", MIN(df->scaling_max_freq, df->max_freq));
1188 }
1189 static DEVICE_ATTR_RW(max_freq);
1190
1191 static ssize_t available_frequencies_show(struct device *d,
1192                                           struct device_attribute *attr,
1193                                           char *buf)
1194 {
1195         struct devfreq *df = to_devfreq(d);
1196         ssize_t count = 0;
1197         int i;
1198
1199         mutex_lock(&df->lock);
1200
1201         for (i = 0; i < df->profile->max_state; i++)
1202                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1203                                 "%lu ", df->profile->freq_table[i]);
1204
1205         mutex_unlock(&df->lock);
1206         /* Truncate the trailing space */
1207         if (count)
1208                 count--;
1209
1210         count += sprintf(&buf[count], "\n");
1211
1212         return count;
1213 }
1214 static DEVICE_ATTR_RO(available_frequencies);
1215
1216 static ssize_t trans_stat_show(struct device *dev,
1217                                struct device_attribute *attr, char *buf)
1218 {
1219         struct devfreq *devfreq = to_devfreq(dev);
1220         ssize_t len;
1221         int i, j;
1222         unsigned int max_state = devfreq->profile->max_state;
1223
1224         if (!devfreq->stop_polling &&
1225                         devfreq_update_status(devfreq, devfreq->previous_freq))
1226                 return 0;
1227         if (max_state == 0)
1228                 return sprintf(buf, "Not Supported.\n");
1229
1230         len = sprintf(buf, "     From  :   To\n");
1231         len += sprintf(buf + len, "           :");
1232         for (i = 0; i < max_state; i++)
1233                 len += sprintf(buf + len, "%10lu",
1234                                 devfreq->profile->freq_table[i]);
1235
1236         len += sprintf(buf + len, "   time(ms)\n");
1237
1238         for (i = 0; i < max_state; i++) {
1239                 if (devfreq->profile->freq_table[i]
1240                                         == devfreq->previous_freq) {
1241                         len += sprintf(buf + len, "*");
1242                 } else {
1243                         len += sprintf(buf + len, " ");
1244                 }
1245                 len += sprintf(buf + len, "%10lu:",
1246                                 devfreq->profile->freq_table[i]);
1247                 for (j = 0; j < max_state; j++)
1248                         len += sprintf(buf + len, "%10u",
1249                                 devfreq->trans_table[(i * max_state) + j]);
1250                 len += sprintf(buf + len, "%10u\n",
1251                         jiffies_to_msecs(devfreq->time_in_state[i]));
1252         }
1253
1254         len += sprintf(buf + len, "Total transition : %u\n",
1255                                         devfreq->total_trans);
1256         return len;
1257 }
1258 static DEVICE_ATTR_RO(trans_stat);
1259
1260 static struct attribute *devfreq_attrs[] = {
1261         &dev_attr_governor.attr,
1262         &dev_attr_available_governors.attr,
1263         &dev_attr_cur_freq.attr,
1264         &dev_attr_available_frequencies.attr,
1265         &dev_attr_target_freq.attr,
1266         &dev_attr_polling_interval.attr,
1267         &dev_attr_min_freq.attr,
1268         &dev_attr_max_freq.attr,
1269         &dev_attr_trans_stat.attr,
1270         NULL,
1271 };
1272 ATTRIBUTE_GROUPS(devfreq);
1273
1274 static int __init devfreq_init(void)
1275 {
1276         devfreq_class = class_create(THIS_MODULE, "devfreq");
1277         if (IS_ERR(devfreq_class)) {
1278                 pr_err("%s: couldn't create class\n", __FILE__);
1279                 return PTR_ERR(devfreq_class);
1280         }
1281
1282         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1283         if (!devfreq_wq) {
1284                 class_destroy(devfreq_class);
1285                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1286                 return -ENOMEM;
1287         }
1288         devfreq_class->dev_groups = devfreq_groups;
1289
1290         return 0;
1291 }
1292 subsys_initcall(devfreq_init);
1293
1294 /*
1295  * The following are helper functions for devfreq user device drivers with
1296  * OPP framework.
1297  */
1298
1299 /**
1300  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1301  *                           freq value given to target callback.
1302  * @dev:        The devfreq user device. (parent of devfreq)
1303  * @freq:       The frequency given to target function
1304  * @flags:      Flags handed from devfreq framework.
1305  *
1306  * The callers are required to call dev_pm_opp_put() for the returned OPP after
1307  * use.
1308  */
1309 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1310                                            unsigned long *freq,
1311                                            u32 flags)
1312 {
1313         struct dev_pm_opp *opp;
1314
1315         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1316                 /* The freq is an upper bound. opp should be lower */
1317                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1318
1319                 /* If not available, use the closest opp */
1320                 if (opp == ERR_PTR(-ERANGE))
1321                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1322         } else {
1323                 /* The freq is an lower bound. opp should be higher */
1324                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1325
1326                 /* If not available, use the closest opp */
1327                 if (opp == ERR_PTR(-ERANGE))
1328                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1329         }
1330
1331         return opp;
1332 }
1333 EXPORT_SYMBOL(devfreq_recommended_opp);
1334
1335 /**
1336  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1337  *                                 for any changes in the OPP availability
1338  *                                 changes
1339  * @dev:        The devfreq user device. (parent of devfreq)
1340  * @devfreq:    The devfreq object.
1341  */
1342 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1343 {
1344         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1345 }
1346 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1347
1348 /**
1349  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1350  *                                   notified for any changes in the OPP
1351  *                                   availability changes anymore.
1352  * @dev:        The devfreq user device. (parent of devfreq)
1353  * @devfreq:    The devfreq object.
1354  *
1355  * At exit() callback of devfreq_dev_profile, this must be included if
1356  * devfreq_recommended_opp is used.
1357  */
1358 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1359 {
1360         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1361 }
1362 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1363
1364 static void devm_devfreq_opp_release(struct device *dev, void *res)
1365 {
1366         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1367 }
1368
1369 /**
1370  * devm_ devfreq_register_opp_notifier()
1371  *              - Resource-managed devfreq_register_opp_notifier()
1372  * @dev:        The devfreq user device. (parent of devfreq)
1373  * @devfreq:    The devfreq object.
1374  */
1375 int devm_devfreq_register_opp_notifier(struct device *dev,
1376                                        struct devfreq *devfreq)
1377 {
1378         struct devfreq **ptr;
1379         int ret;
1380
1381         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1382         if (!ptr)
1383                 return -ENOMEM;
1384
1385         ret = devfreq_register_opp_notifier(dev, devfreq);
1386         if (ret) {
1387                 devres_free(ptr);
1388                 return ret;
1389         }
1390
1391         *ptr = devfreq;
1392         devres_add(dev, ptr);
1393
1394         return 0;
1395 }
1396 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1397
1398 /**
1399  * devm_devfreq_unregister_opp_notifier()
1400  *              - Resource-managed devfreq_unregister_opp_notifier()
1401  * @dev:        The devfreq user device. (parent of devfreq)
1402  * @devfreq:    The devfreq object.
1403  */
1404 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1405                                          struct devfreq *devfreq)
1406 {
1407         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1408                                devm_devfreq_dev_match, devfreq));
1409 }
1410 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1411
1412 /**
1413  * devfreq_register_notifier() - Register a driver with devfreq
1414  * @devfreq:    The devfreq object.
1415  * @nb:         The notifier block to register.
1416  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1417  */
1418 int devfreq_register_notifier(struct devfreq *devfreq,
1419                                 struct notifier_block *nb,
1420                                 unsigned int list)
1421 {
1422         int ret = 0;
1423
1424         if (!devfreq)
1425                 return -EINVAL;
1426
1427         switch (list) {
1428         case DEVFREQ_TRANSITION_NOTIFIER:
1429                 ret = srcu_notifier_chain_register(
1430                                 &devfreq->transition_notifier_list, nb);
1431                 break;
1432         default:
1433                 ret = -EINVAL;
1434         }
1435
1436         return ret;
1437 }
1438 EXPORT_SYMBOL(devfreq_register_notifier);
1439
1440 /*
1441  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1442  * @devfreq:    The devfreq object.
1443  * @nb:         The notifier block to be unregistered.
1444  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1445  */
1446 int devfreq_unregister_notifier(struct devfreq *devfreq,
1447                                 struct notifier_block *nb,
1448                                 unsigned int list)
1449 {
1450         int ret = 0;
1451
1452         if (!devfreq)
1453                 return -EINVAL;
1454
1455         switch (list) {
1456         case DEVFREQ_TRANSITION_NOTIFIER:
1457                 ret = srcu_notifier_chain_unregister(
1458                                 &devfreq->transition_notifier_list, nb);
1459                 break;
1460         default:
1461                 ret = -EINVAL;
1462         }
1463
1464         return ret;
1465 }
1466 EXPORT_SYMBOL(devfreq_unregister_notifier);
1467
1468 struct devfreq_notifier_devres {
1469         struct devfreq *devfreq;
1470         struct notifier_block *nb;
1471         unsigned int list;
1472 };
1473
1474 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1475 {
1476         struct devfreq_notifier_devres *this = res;
1477
1478         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1479 }
1480
1481 /**
1482  * devm_devfreq_register_notifier()
1483         - Resource-managed devfreq_register_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 int devm_devfreq_register_notifier(struct device *dev,
1490                                 struct devfreq *devfreq,
1491                                 struct notifier_block *nb,
1492                                 unsigned int list)
1493 {
1494         struct devfreq_notifier_devres *ptr;
1495         int ret;
1496
1497         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1498                                 GFP_KERNEL);
1499         if (!ptr)
1500                 return -ENOMEM;
1501
1502         ret = devfreq_register_notifier(devfreq, nb, list);
1503         if (ret) {
1504                 devres_free(ptr);
1505                 return ret;
1506         }
1507
1508         ptr->devfreq = devfreq;
1509         ptr->nb = nb;
1510         ptr->list = list;
1511         devres_add(dev, ptr);
1512
1513         return 0;
1514 }
1515 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1516
1517 /**
1518  * devm_devfreq_unregister_notifier()
1519         - Resource-managed devfreq_unregister_notifier()
1520  * @dev:        The devfreq user device. (parent of devfreq)
1521  * @devfreq:    The devfreq object.
1522  * @nb:         The notifier block to be unregistered.
1523  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1524  */
1525 void devm_devfreq_unregister_notifier(struct device *dev,
1526                                 struct devfreq *devfreq,
1527                                 struct notifier_block *nb,
1528                                 unsigned int list)
1529 {
1530         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1531                                devm_devfreq_dev_match, devfreq));
1532 }
1533 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);