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 devfreq;
 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 && df->governor->immutable) ||
1000                                         governor->immutable) {
1001                 ret = -EINVAL;
1002                 goto out;
1003         }
1004
1005         if (df->governor) {
1006                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1007                 if (ret) {
1008                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1009                                  __func__, df->governor->name, ret);
1010                         goto out;
1011                 }
1012         }
1013         df->governor = governor;
1014         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1015         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1016         if (ret)
1017                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1018                          __func__, df->governor->name, ret);
1019 out:
1020         mutex_unlock(&devfreq_list_lock);
1021
1022         if (!ret)
1023                 ret = count;
1024         return ret;
1025 }
1026 static DEVICE_ATTR_RW(governor);
1027
1028 static ssize_t available_governors_show(struct device *d,
1029                                         struct device_attribute *attr,
1030                                         char *buf)
1031 {
1032         struct devfreq *df = to_devfreq(d);
1033         ssize_t count = 0;
1034
1035         mutex_lock(&devfreq_list_lock);
1036
1037         /*
1038          * The devfreq with immutable governor (e.g., passive) shows
1039          * only own governor.
1040          */
1041         if (df->governor->immutable) {
1042                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1043                                    "%s ", df->governor_name);
1044         /*
1045          * The devfreq device shows the registered governor except for
1046          * immutable governors such as passive governor .
1047          */
1048         } else {
1049                 struct devfreq_governor *governor;
1050
1051                 list_for_each_entry(governor, &devfreq_governor_list, node) {
1052                         if (governor->immutable)
1053                                 continue;
1054                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1055                                            "%s ", governor->name);
1056                 }
1057         }
1058
1059         mutex_unlock(&devfreq_list_lock);
1060
1061         /* Truncate the trailing space */
1062         if (count)
1063                 count--;
1064
1065         count += sprintf(&buf[count], "\n");
1066
1067         return count;
1068 }
1069 static DEVICE_ATTR_RO(available_governors);
1070
1071 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1072                              char *buf)
1073 {
1074         unsigned long freq;
1075         struct devfreq *devfreq = to_devfreq(dev);
1076
1077         if (devfreq->profile->get_cur_freq &&
1078                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1079                 return sprintf(buf, "%lu\n", freq);
1080
1081         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1082 }
1083 static DEVICE_ATTR_RO(cur_freq);
1084
1085 static ssize_t target_freq_show(struct device *dev,
1086                                 struct device_attribute *attr, char *buf)
1087 {
1088         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1089 }
1090 static DEVICE_ATTR_RO(target_freq);
1091
1092 static ssize_t polling_interval_show(struct device *dev,
1093                                      struct device_attribute *attr, char *buf)
1094 {
1095         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1096 }
1097
1098 static ssize_t polling_interval_store(struct device *dev,
1099                                       struct device_attribute *attr,
1100                                       const char *buf, size_t count)
1101 {
1102         struct devfreq *df = to_devfreq(dev);
1103         unsigned int value;
1104         int ret;
1105
1106         if (!df->governor)
1107                 return -EINVAL;
1108
1109         ret = sscanf(buf, "%u", &value);
1110         if (ret != 1)
1111                 return -EINVAL;
1112
1113         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1114         ret = count;
1115
1116         return ret;
1117 }
1118 static DEVICE_ATTR_RW(polling_interval);
1119
1120 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1121                               const char *buf, size_t count)
1122 {
1123         struct devfreq *df = to_devfreq(dev);
1124         unsigned long value;
1125         int ret;
1126         unsigned long max;
1127
1128         ret = sscanf(buf, "%lu", &value);
1129         if (ret != 1)
1130                 return -EINVAL;
1131
1132         mutex_lock(&df->lock);
1133         max = df->max_freq;
1134         if (value && max && value > max) {
1135                 ret = -EINVAL;
1136                 goto unlock;
1137         }
1138
1139         df->min_freq = value;
1140         update_devfreq(df);
1141         ret = count;
1142 unlock:
1143         mutex_unlock(&df->lock);
1144         return ret;
1145 }
1146
1147 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1148                              char *buf)
1149 {
1150         struct devfreq *df = to_devfreq(dev);
1151
1152         return sprintf(buf, "%lu\n", MAX(df->scaling_min_freq, df->min_freq));
1153 }
1154
1155 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1156                               const char *buf, size_t count)
1157 {
1158         struct devfreq *df = to_devfreq(dev);
1159         unsigned long value;
1160         int ret;
1161         unsigned long min;
1162
1163         ret = sscanf(buf, "%lu", &value);
1164         if (ret != 1)
1165                 return -EINVAL;
1166
1167         mutex_lock(&df->lock);
1168         min = df->min_freq;
1169         if (value && min && value < min) {
1170                 ret = -EINVAL;
1171                 goto unlock;
1172         }
1173
1174         df->max_freq = value;
1175         update_devfreq(df);
1176         ret = count;
1177 unlock:
1178         mutex_unlock(&df->lock);
1179         return ret;
1180 }
1181 static DEVICE_ATTR_RW(min_freq);
1182
1183 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1184                              char *buf)
1185 {
1186         struct devfreq *df = to_devfreq(dev);
1187
1188         return sprintf(buf, "%lu\n", MIN(df->scaling_max_freq, df->max_freq));
1189 }
1190 static DEVICE_ATTR_RW(max_freq);
1191
1192 static ssize_t available_frequencies_show(struct device *d,
1193                                           struct device_attribute *attr,
1194                                           char *buf)
1195 {
1196         struct devfreq *df = to_devfreq(d);
1197         ssize_t count = 0;
1198         int i;
1199
1200         mutex_lock(&df->lock);
1201
1202         for (i = 0; i < df->profile->max_state; i++)
1203                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1204                                 "%lu ", df->profile->freq_table[i]);
1205
1206         mutex_unlock(&df->lock);
1207         /* Truncate the trailing space */
1208         if (count)
1209                 count--;
1210
1211         count += sprintf(&buf[count], "\n");
1212
1213         return count;
1214 }
1215 static DEVICE_ATTR_RO(available_frequencies);
1216
1217 static ssize_t trans_stat_show(struct device *dev,
1218                                struct device_attribute *attr, char *buf)
1219 {
1220         struct devfreq *devfreq = to_devfreq(dev);
1221         ssize_t len;
1222         int i, j;
1223         unsigned int max_state = devfreq->profile->max_state;
1224
1225         if (!devfreq->stop_polling &&
1226                         devfreq_update_status(devfreq, devfreq->previous_freq))
1227                 return 0;
1228         if (max_state == 0)
1229                 return sprintf(buf, "Not Supported.\n");
1230
1231         len = sprintf(buf, "     From  :   To\n");
1232         len += sprintf(buf + len, "           :");
1233         for (i = 0; i < max_state; i++)
1234                 len += sprintf(buf + len, "%10lu",
1235                                 devfreq->profile->freq_table[i]);
1236
1237         len += sprintf(buf + len, "   time(ms)\n");
1238
1239         for (i = 0; i < max_state; i++) {
1240                 if (devfreq->profile->freq_table[i]
1241                                         == devfreq->previous_freq) {
1242                         len += sprintf(buf + len, "*");
1243                 } else {
1244                         len += sprintf(buf + len, " ");
1245                 }
1246                 len += sprintf(buf + len, "%10lu:",
1247                                 devfreq->profile->freq_table[i]);
1248                 for (j = 0; j < max_state; j++)
1249                         len += sprintf(buf + len, "%10u",
1250                                 devfreq->trans_table[(i * max_state) + j]);
1251                 len += sprintf(buf + len, "%10u\n",
1252                         jiffies_to_msecs(devfreq->time_in_state[i]));
1253         }
1254
1255         len += sprintf(buf + len, "Total transition : %u\n",
1256                                         devfreq->total_trans);
1257         return len;
1258 }
1259 static DEVICE_ATTR_RO(trans_stat);
1260
1261 static struct attribute *devfreq_attrs[] = {
1262         &dev_attr_governor.attr,
1263         &dev_attr_available_governors.attr,
1264         &dev_attr_cur_freq.attr,
1265         &dev_attr_available_frequencies.attr,
1266         &dev_attr_target_freq.attr,
1267         &dev_attr_polling_interval.attr,
1268         &dev_attr_min_freq.attr,
1269         &dev_attr_max_freq.attr,
1270         &dev_attr_trans_stat.attr,
1271         NULL,
1272 };
1273 ATTRIBUTE_GROUPS(devfreq);
1274
1275 static int __init devfreq_init(void)
1276 {
1277         devfreq_class = class_create(THIS_MODULE, "devfreq");
1278         if (IS_ERR(devfreq_class)) {
1279                 pr_err("%s: couldn't create class\n", __FILE__);
1280                 return PTR_ERR(devfreq_class);
1281         }
1282
1283         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1284         if (!devfreq_wq) {
1285                 class_destroy(devfreq_class);
1286                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1287                 return -ENOMEM;
1288         }
1289         devfreq_class->dev_groups = devfreq_groups;
1290
1291         return 0;
1292 }
1293 subsys_initcall(devfreq_init);
1294
1295 /*
1296  * The following are helper functions for devfreq user device drivers with
1297  * OPP framework.
1298  */
1299
1300 /**
1301  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1302  *                           freq value given to target callback.
1303  * @dev:        The devfreq user device. (parent of devfreq)
1304  * @freq:       The frequency given to target function
1305  * @flags:      Flags handed from devfreq framework.
1306  *
1307  * The callers are required to call dev_pm_opp_put() for the returned OPP after
1308  * use.
1309  */
1310 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1311                                            unsigned long *freq,
1312                                            u32 flags)
1313 {
1314         struct dev_pm_opp *opp;
1315
1316         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1317                 /* The freq is an upper bound. opp should be lower */
1318                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1319
1320                 /* If not available, use the closest opp */
1321                 if (opp == ERR_PTR(-ERANGE))
1322                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1323         } else {
1324                 /* The freq is an lower bound. opp should be higher */
1325                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1326
1327                 /* If not available, use the closest opp */
1328                 if (opp == ERR_PTR(-ERANGE))
1329                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1330         }
1331
1332         return opp;
1333 }
1334 EXPORT_SYMBOL(devfreq_recommended_opp);
1335
1336 /**
1337  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1338  *                                 for any changes in the OPP availability
1339  *                                 changes
1340  * @dev:        The devfreq user device. (parent of devfreq)
1341  * @devfreq:    The devfreq object.
1342  */
1343 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1344 {
1345         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1346 }
1347 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1348
1349 /**
1350  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1351  *                                   notified for any changes in the OPP
1352  *                                   availability changes anymore.
1353  * @dev:        The devfreq user device. (parent of devfreq)
1354  * @devfreq:    The devfreq object.
1355  *
1356  * At exit() callback of devfreq_dev_profile, this must be included if
1357  * devfreq_recommended_opp is used.
1358  */
1359 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1360 {
1361         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1362 }
1363 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1364
1365 static void devm_devfreq_opp_release(struct device *dev, void *res)
1366 {
1367         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1368 }
1369
1370 /**
1371  * devm_ devfreq_register_opp_notifier()
1372  *              - Resource-managed devfreq_register_opp_notifier()
1373  * @dev:        The devfreq user device. (parent of devfreq)
1374  * @devfreq:    The devfreq object.
1375  */
1376 int devm_devfreq_register_opp_notifier(struct device *dev,
1377                                        struct devfreq *devfreq)
1378 {
1379         struct devfreq **ptr;
1380         int ret;
1381
1382         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1383         if (!ptr)
1384                 return -ENOMEM;
1385
1386         ret = devfreq_register_opp_notifier(dev, devfreq);
1387         if (ret) {
1388                 devres_free(ptr);
1389                 return ret;
1390         }
1391
1392         *ptr = devfreq;
1393         devres_add(dev, ptr);
1394
1395         return 0;
1396 }
1397 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1398
1399 /**
1400  * devm_devfreq_unregister_opp_notifier()
1401  *              - Resource-managed devfreq_unregister_opp_notifier()
1402  * @dev:        The devfreq user device. (parent of devfreq)
1403  * @devfreq:    The devfreq object.
1404  */
1405 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1406                                          struct devfreq *devfreq)
1407 {
1408         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1409                                devm_devfreq_dev_match, devfreq));
1410 }
1411 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1412
1413 /**
1414  * devfreq_register_notifier() - Register a driver with devfreq
1415  * @devfreq:    The devfreq object.
1416  * @nb:         The notifier block to register.
1417  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1418  */
1419 int devfreq_register_notifier(struct devfreq *devfreq,
1420                                 struct notifier_block *nb,
1421                                 unsigned int list)
1422 {
1423         int ret = 0;
1424
1425         if (!devfreq)
1426                 return -EINVAL;
1427
1428         switch (list) {
1429         case DEVFREQ_TRANSITION_NOTIFIER:
1430                 ret = srcu_notifier_chain_register(
1431                                 &devfreq->transition_notifier_list, nb);
1432                 break;
1433         default:
1434                 ret = -EINVAL;
1435         }
1436
1437         return ret;
1438 }
1439 EXPORT_SYMBOL(devfreq_register_notifier);
1440
1441 /*
1442  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1443  * @devfreq:    The devfreq object.
1444  * @nb:         The notifier block to be unregistered.
1445  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1446  */
1447 int devfreq_unregister_notifier(struct devfreq *devfreq,
1448                                 struct notifier_block *nb,
1449                                 unsigned int list)
1450 {
1451         int ret = 0;
1452
1453         if (!devfreq)
1454                 return -EINVAL;
1455
1456         switch (list) {
1457         case DEVFREQ_TRANSITION_NOTIFIER:
1458                 ret = srcu_notifier_chain_unregister(
1459                                 &devfreq->transition_notifier_list, nb);
1460                 break;
1461         default:
1462                 ret = -EINVAL;
1463         }
1464
1465         return ret;
1466 }
1467 EXPORT_SYMBOL(devfreq_unregister_notifier);
1468
1469 struct devfreq_notifier_devres {
1470         struct devfreq *devfreq;
1471         struct notifier_block *nb;
1472         unsigned int list;
1473 };
1474
1475 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1476 {
1477         struct devfreq_notifier_devres *this = res;
1478
1479         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1480 }
1481
1482 /**
1483  * devm_devfreq_register_notifier()
1484         - Resource-managed devfreq_register_notifier()
1485  * @dev:        The devfreq user device. (parent of devfreq)
1486  * @devfreq:    The devfreq object.
1487  * @nb:         The notifier block to be unregistered.
1488  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1489  */
1490 int devm_devfreq_register_notifier(struct device *dev,
1491                                 struct devfreq *devfreq,
1492                                 struct notifier_block *nb,
1493                                 unsigned int list)
1494 {
1495         struct devfreq_notifier_devres *ptr;
1496         int ret;
1497
1498         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1499                                 GFP_KERNEL);
1500         if (!ptr)
1501                 return -ENOMEM;
1502
1503         ret = devfreq_register_notifier(devfreq, nb, list);
1504         if (ret) {
1505                 devres_free(ptr);
1506                 return ret;
1507         }
1508
1509         ptr->devfreq = devfreq;
1510         ptr->nb = nb;
1511         ptr->list = list;
1512         devres_add(dev, ptr);
1513
1514         return 0;
1515 }
1516 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1517
1518 /**
1519  * devm_devfreq_unregister_notifier()
1520         - Resource-managed devfreq_unregister_notifier()
1521  * @dev:        The devfreq user device. (parent of devfreq)
1522  * @devfreq:    The devfreq object.
1523  * @nb:         The notifier block to be unregistered.
1524  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1525  */
1526 void devm_devfreq_unregister_notifier(struct device *dev,
1527                                 struct devfreq *devfreq,
1528                                 struct notifier_block *nb,
1529                                 unsigned int list)
1530 {
1531         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1532                                devm_devfreq_dev_match, devfreq));
1533 }
1534 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);