drivers/devfreq/devfreq.c

   1 /*
   2  * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
   3  *          for Non-CPU Devices.
   4  *
   5  * Copyright (C) 2011 Samsung Electronics
   6  *      MyungJoo Ham <myungjoo.ham@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/errno.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/export.h>
  19 #include <linux/slab.h>
  20 #include <linux/stat.h>
  21 #include <linux/pm_opp.h>
  22 #include <linux/devfreq.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/list.h>
  26 #include <linux/printk.h>
  27 #include <linux/hrtimer.h>
  28 #include <linux/of.h>
  29 #include "governor.h"
  30
  31 static struct class *devfreq_class;
  32
  33 /*
  34  * devfreq core provides delayed work based load monitoring helper
  35  * functions. Governors can use these or can implement their own
  36  * monitoring mechanism.
  37  */
  38 static struct workqueue_struct *devfreq_wq;
  39
  40 /* The list of all device-devfreq governors */
  41 static LIST_HEAD(devfreq_governor_list);
  42 /* The list of all device-devfreq */
  43 static LIST_HEAD(devfreq_list);
  44 static DEFINE_MUTEX(devfreq_list_lock);
  45
  46 /**
  47  * find_device_devfreq() - find devfreq struct using device pointer
  48  * @dev:        device pointer used to lookup device devfreq.
  49  *
  50  * Search the list of device devfreqs and return the matched device's
  51  * devfreq info. devfreq_list_lock should be held by the caller.
  52  */
  53 static struct devfreq *find_device_devfreq(struct device *dev)
  54 {
  55         struct devfreq *tmp_devfreq;
  56
  57         if (IS_ERR_OR_NULL(dev)) {
  58                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  59                 return ERR_PTR(-EINVAL);
  60         }
  61         WARN(!mutex_is_locked(&devfreq_list_lock),
  62              "devfreq_list_lock must be locked.");
  63
  64         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  65                 if (tmp_devfreq->dev.parent == dev)
  66                         return tmp_devfreq;
  67         }
  68
  69         return ERR_PTR(-ENODEV);
  70 }
  71
  72 /**
  73  * devfreq_get_freq_level() - Lookup freq_table for the frequency
  74  * @devfreq:    the devfreq instance
  75  * @freq:       the target frequency
  76  */
  77 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
  78 {
  79         int lev;
  80
  81         for (lev = 0; lev < devfreq->profile->max_state; lev++)
  82                 if (freq == devfreq->profile->freq_table[lev])
  83                         return lev;
  84
  85         return -EINVAL;
  86 }
  87
  88 /**
  89  * devfreq_set_freq_table() - Initialize freq_table for the frequency
  90  * @devfreq:    the devfreq instance
  91  */
  92 static void devfreq_set_freq_table(struct devfreq *devfreq)
  93 {
  94         struct devfreq_dev_profile *profile = devfreq->profile;
  95         struct dev_pm_opp *opp;
  96         unsigned long freq;
  97         int i, count;
  98
  99         /* Initialize the freq_table from OPP table */
 100         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 101         if (count <= 0)
 102                 return;
 103
 104         profile->max_state = count;
 105         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 106                                         profile->max_state,
 107                                         sizeof(*profile->freq_table),
 108                                         GFP_KERNEL);
 109         if (!profile->freq_table) {
 110                 profile->max_state = 0;
 111                 return;
 112         }
 113
 114         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 115                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 116                 if (IS_ERR(opp)) {
 117                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 118                         profile->max_state = 0;
 119                         return;
 120                 }
 121                 dev_pm_opp_put(opp);
 122                 profile->freq_table[i] = freq;
 123         }
 124 }
 125
 126 /**
 127  * devfreq_update_status() - Update statistics of devfreq behavior
 128  * @devfreq:    the devfreq instance
 129  * @freq:       the update target frequency
 130  */
 131 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 132 {
 133         int lev, prev_lev, ret = 0;
 134         unsigned long cur_time;
 135
 136         lockdep_assert_held(&devfreq->lock);
 137         cur_time = jiffies;
 138
 139         /* Immediately exit if previous_freq is not initialized yet. */
 140         if (!devfreq->previous_freq)
 141                 goto out;
 142
 143         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 144         if (prev_lev < 0) {
 145                 ret = prev_lev;
 146                 goto out;
 147         }
 148
 149         devfreq->time_in_state[prev_lev] +=
 150                          cur_time - devfreq->last_stat_updated;
 151
 152         lev = devfreq_get_freq_level(devfreq, freq);
 153         if (lev < 0) {
 154                 ret = lev;
 155                 goto out;
 156         }
 157
 158         if (lev != prev_lev) {
 159                 devfreq->trans_table[(prev_lev *
 160                                 devfreq->profile->max_state) + lev]++;
 161                 devfreq->total_trans++;
 162         }
 163
 164 out:
 165         devfreq->last_stat_updated = cur_time;
 166         return ret;
 167 }
 168 EXPORT_SYMBOL(devfreq_update_status);
 169
 170 /**
 171  * find_devfreq_governor() - find devfreq governor from name
 172  * @name:       name of the governor
 173  *
 174  * Search the list of devfreq governors and return the matched
 175  * governor's pointer. devfreq_list_lock should be held by the caller.
 176  */
 177 static struct devfreq_governor *find_devfreq_governor(const char *name)
 178 {
 179         struct devfreq_governor *tmp_governor;
 180
 181         if (IS_ERR_OR_NULL(name)) {
 182                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 183                 return ERR_PTR(-EINVAL);
 184         }
 185         WARN(!mutex_is_locked(&devfreq_list_lock),
 186              "devfreq_list_lock must be locked.");
 187
 188         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 189                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 190                         return tmp_governor;
 191         }
 192
 193         return ERR_PTR(-ENODEV);
 194 }
 195
 196 static int devfreq_notify_transition(struct devfreq *devfreq,
 197                 struct devfreq_freqs *freqs, unsigned int state)
 198 {
 199         if (!devfreq)
 200                 return -EINVAL;
 201
 202         switch (state) {
 203         case DEVFREQ_PRECHANGE:
 204                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 205                                 DEVFREQ_PRECHANGE, freqs);
 206                 break;
 207
 208         case DEVFREQ_POSTCHANGE:
 209                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 210                                 DEVFREQ_POSTCHANGE, freqs);
 211                 break;
 212         default:
 213                 return -EINVAL;
 214         }
 215
 216         return 0;
 217 }
 218
 219 /* Load monitoring helper functions for governors use */
 220
 221 /**
 222  * update_devfreq() - Reevaluate the device and configure frequency.
 223  * @devfreq:    the devfreq instance.
 224  *
 225  * Note: Lock devfreq->lock before calling update_devfreq
 226  *       This function is exported for governors.
 227  */
 228 int update_devfreq(struct devfreq *devfreq)
 229 {
 230         struct devfreq_freqs freqs;
 231         unsigned long freq, cur_freq;
 232         int err = 0;
 233         u32 flags = 0;
 234
 235         if (!mutex_is_locked(&devfreq->lock)) {
 236                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 237                 return -EINVAL;
 238         }
 239
 240         if (!devfreq->governor)
 241                 return -EINVAL;
 242
 243         /* Reevaluate the proper frequency */
 244         err = devfreq->governor->get_target_freq(devfreq, &freq);
 245         if (err)
 246                 return err;
 247
 248         /*
 249          * Adjust the frequency with user freq and QoS.
 250          *
 251          * List from the highest priority
 252          * max_freq
 253          * min_freq
 254          */
 255
 256         if (devfreq->min_freq && freq < devfreq->min_freq) {
 257                 freq = devfreq->min_freq;
 258                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 259         }
 260         if (devfreq->max_freq && freq > devfreq->max_freq) {
 261                 freq = devfreq->max_freq;
 262                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 263         }
 264
 265         if (devfreq->profile->get_cur_freq)
 266                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 267         else
 268                 cur_freq = devfreq->previous_freq;
 269
 270         freqs.old = cur_freq;
 271         freqs.new = freq;
 272         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 273
 274         err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 275         if (err) {
 276                 freqs.new = cur_freq;
 277                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 278                 return err;
 279         }
 280
 281         freqs.new = freq;
 282         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 283
 284         if (devfreq->profile->freq_table)
 285                 if (devfreq_update_status(devfreq, freq))
 286                         dev_err(&devfreq->dev,
 287                                 "Couldn't update frequency transition information.\n");
 288
 289         devfreq->previous_freq = freq;
 290         return err;
 291 }
 292 EXPORT_SYMBOL(update_devfreq);
 293
 294 /**
 295  * devfreq_monitor() - Periodically poll devfreq objects.
 296  * @work:       the work struct used to run devfreq_monitor periodically.
 297  *
 298  */
 299 static void devfreq_monitor(struct work_struct *work)
 300 {
 301         int err;
 302         struct devfreq *devfreq = container_of(work,
 303                                         struct devfreq, work.work);
 304
 305         mutex_lock(&devfreq->lock);
 306         err = update_devfreq(devfreq);
 307         if (err)
 308                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 309
 310         queue_delayed_work(devfreq_wq, &devfreq->work,
 311                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 312         mutex_unlock(&devfreq->lock);
 313 }
 314
 315 /**
 316  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 317  * @devfreq:    the devfreq instance.
 318  *
 319  * Helper function for starting devfreq device load monitoing. By
 320  * default delayed work based monitoring is supported. Function
 321  * to be called from governor in response to DEVFREQ_GOV_START
 322  * event when device is added to devfreq framework.
 323  */
 324 void devfreq_monitor_start(struct devfreq *devfreq)
 325 {
 326         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 327         if (devfreq->profile->polling_ms)
 328                 queue_delayed_work(devfreq_wq, &devfreq->work,
 329                         msecs_to_jiffies(devfreq->profile->polling_ms));
 330 }
 331 EXPORT_SYMBOL(devfreq_monitor_start);
 332
 333 /**
 334  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 335  * @devfreq:    the devfreq instance.
 336  *
 337  * Helper function to stop devfreq device load monitoing. Function
 338  * to be called from governor in response to DEVFREQ_GOV_STOP
 339  * event when device is removed from devfreq framework.
 340  */
 341 void devfreq_monitor_stop(struct devfreq *devfreq)
 342 {
 343         cancel_delayed_work_sync(&devfreq->work);
 344 }
 345 EXPORT_SYMBOL(devfreq_monitor_stop);
 346
 347 /**
 348  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 349  * @devfreq:    the devfreq instance.
 350  *
 351  * Helper function to suspend devfreq device load monitoing. Function
 352  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 353  * event or when polling interval is set to zero.
 354  *
 355  * Note: Though this function is same as devfreq_monitor_stop(),
 356  * intentionally kept separate to provide hooks for collecting
 357  * transition statistics.
 358  */
 359 void devfreq_monitor_suspend(struct devfreq *devfreq)
 360 {
 361         mutex_lock(&devfreq->lock);
 362         if (devfreq->stop_polling) {
 363                 mutex_unlock(&devfreq->lock);
 364                 return;
 365         }
 366
 367         devfreq_update_status(devfreq, devfreq->previous_freq);
 368         devfreq->stop_polling = true;
 369         mutex_unlock(&devfreq->lock);
 370         cancel_delayed_work_sync(&devfreq->work);
 371 }
 372 EXPORT_SYMBOL(devfreq_monitor_suspend);
 373
 374 /**
 375  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 376  * @devfreq:    the devfreq instance.
 377  *
 378  * Helper function to resume devfreq device load monitoing. Function
 379  * to be called from governor in response to DEVFREQ_GOV_RESUME
 380  * event or when polling interval is set to non-zero.
 381  */
 382 void devfreq_monitor_resume(struct devfreq *devfreq)
 383 {
 384         unsigned long freq;
 385
 386         mutex_lock(&devfreq->lock);
 387         if (!devfreq->stop_polling)
 388                 goto out;
 389
 390         if (!delayed_work_pending(&devfreq->work) &&
 391                         devfreq->profile->polling_ms)
 392                 queue_delayed_work(devfreq_wq, &devfreq->work,
 393                         msecs_to_jiffies(devfreq->profile->polling_ms));
 394
 395         devfreq->last_stat_updated = jiffies;
 396         devfreq->stop_polling = false;
 397
 398         if (devfreq->profile->get_cur_freq &&
 399                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 400                 devfreq->previous_freq = freq;
 401
 402 out:
 403         mutex_unlock(&devfreq->lock);
 404 }
 405 EXPORT_SYMBOL(devfreq_monitor_resume);
 406
 407 /**
 408  * devfreq_interval_update() - Update device devfreq monitoring interval
 409  * @devfreq:    the devfreq instance.
 410  * @delay:      new polling interval to be set.
 411  *
 412  * Helper function to set new load monitoring polling interval. Function
 413  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 414  */
 415 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 416 {
 417         unsigned int cur_delay = devfreq->profile->polling_ms;
 418         unsigned int new_delay = *delay;
 419
 420         mutex_lock(&devfreq->lock);
 421         devfreq->profile->polling_ms = new_delay;
 422
 423         if (devfreq->stop_polling)
 424                 goto out;
 425
 426         /* if new delay is zero, stop polling */
 427         if (!new_delay) {
 428                 mutex_unlock(&devfreq->lock);
 429                 cancel_delayed_work_sync(&devfreq->work);
 430                 return;
 431         }
 432
 433         /* if current delay is zero, start polling with new delay */
 434         if (!cur_delay) {
 435                 queue_delayed_work(devfreq_wq, &devfreq->work,
 436                         msecs_to_jiffies(devfreq->profile->polling_ms));
 437                 goto out;
 438         }
 439
 440         /* if current delay is greater than new delay, restart polling */
 441         if (cur_delay > new_delay) {
 442                 mutex_unlock(&devfreq->lock);
 443                 cancel_delayed_work_sync(&devfreq->work);
 444                 mutex_lock(&devfreq->lock);
 445                 if (!devfreq->stop_polling)
 446                         queue_delayed_work(devfreq_wq, &devfreq->work,
 447                               msecs_to_jiffies(devfreq->profile->polling_ms));
 448         }
 449 out:
 450         mutex_unlock(&devfreq->lock);
 451 }
 452 EXPORT_SYMBOL(devfreq_interval_update);
 453
 454 /**
 455  * devfreq_notifier_call() - Notify that the device frequency requirements
 456  *                         has been changed out of devfreq framework.
 457  * @nb:         the notifier_block (supposed to be devfreq->nb)
 458  * @type:       not used
 459  * @devp:       not used
 460  *
 461  * Called by a notifier that uses devfreq->nb.
 462  */
 463 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 464                                  void *devp)
 465 {
 466         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 467         int ret;
 468
 469         mutex_lock(&devfreq->lock);
 470         ret = update_devfreq(devfreq);
 471         mutex_unlock(&devfreq->lock);
 472
 473         return ret;
 474 }
 475
 476 /**
 477  * devfreq_dev_release() - Callback for struct device to release the device.
 478  * @dev:        the devfreq device
 479  *
 480  * Remove devfreq from the list and release its resources.
 481  */
 482 static void devfreq_dev_release(struct device *dev)
 483 {
 484         struct devfreq *devfreq = to_devfreq(dev);
 485
 486         mutex_lock(&devfreq_list_lock);
 487         list_del(&devfreq->node);
 488         mutex_unlock(&devfreq_list_lock);
 489
 490         if (devfreq->governor)
 491                 devfreq->governor->event_handler(devfreq,
 492                                                  DEVFREQ_GOV_STOP, NULL);
 493
 494         if (devfreq->profile->exit)
 495                 devfreq->profile->exit(devfreq->dev.parent);
 496
 497         mutex_destroy(&devfreq->lock);
 498         kfree(devfreq);
 499 }
 500
 501 /**
 502  * devfreq_add_device() - Add devfreq feature to the device
 503  * @dev:        the device to add devfreq feature.
 504  * @profile:    device-specific profile to run devfreq.
 505  * @governor_name:      name of the policy to choose frequency.
 506  * @data:       private data for the governor. The devfreq framework does not
 507  *              touch this value.
 508  */
 509 struct devfreq *devfreq_add_device(struct device *dev,
 510                                    struct devfreq_dev_profile *profile,
 511                                    const char *governor_name,
 512                                    void *data)
 513 {
 514         struct devfreq *devfreq;
 515         struct devfreq_governor *governor;
 516         int err = 0;
 517
 518         if (!dev || !profile || !governor_name) {
 519                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 520                 return ERR_PTR(-EINVAL);
 521         }
 522
 523         mutex_lock(&devfreq_list_lock);
 524         devfreq = find_device_devfreq(dev);
 525         mutex_unlock(&devfreq_list_lock);
 526         if (!IS_ERR(devfreq)) {
 527                 dev_err(dev, "%s: Unable to create devfreq for the device.\n",
 528                         __func__);
 529                 err = -EINVAL;
 530                 goto err_out;
 531         }
 532
 533         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 534         if (!devfreq) {
 535                 err = -ENOMEM;
 536                 goto err_out;
 537         }
 538
 539         mutex_init(&devfreq->lock);
 540         mutex_lock(&devfreq->lock);
 541         devfreq->dev.parent = dev;
 542         devfreq->dev.class = devfreq_class;
 543         devfreq->dev.release = devfreq_dev_release;
 544         INIT_LIST_HEAD(&devfreq->node);
 545         devfreq->profile = profile;
 546         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 547         devfreq->previous_freq = profile->initial_freq;
 548         devfreq->last_status.current_frequency = profile->initial_freq;
 549         devfreq->data = data;
 550         devfreq->nb.notifier_call = devfreq_notifier_call;
 551
 552         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 553                 mutex_unlock(&devfreq->lock);
 554                 devfreq_set_freq_table(devfreq);
 555                 mutex_lock(&devfreq->lock);
 556         }
 557
 558         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 559         err = device_register(&devfreq->dev);
 560         if (err) {
 561                 mutex_unlock(&devfreq->lock);
 562                 goto err_dev;
 563         }
 564
 565         devfreq->trans_table =  devm_kzalloc(&devfreq->dev,
 566                                                 sizeof(unsigned int) *
 567                                                 devfreq->profile->max_state *
 568                                                 devfreq->profile->max_state,
 569                                                 GFP_KERNEL);
 570         devfreq->time_in_state = devm_kzalloc(&devfreq->dev,
 571                                                 sizeof(unsigned long) *
 572                                                 devfreq->profile->max_state,
 573                                                 GFP_KERNEL);
 574         devfreq->last_stat_updated = jiffies;
 575
 576         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 577
 578         mutex_unlock(&devfreq->lock);
 579
 580         mutex_lock(&devfreq_list_lock);
 581         list_add(&devfreq->node, &devfreq_list);
 582
 583         governor = find_devfreq_governor(devfreq->governor_name);
 584         if (IS_ERR(governor)) {
 585                 dev_err(dev, "%s: Unable to find governor for the device\n",
 586                         __func__);
 587                 err = PTR_ERR(governor);
 588                 goto err_init;
 589         }
 590
 591         devfreq->governor = governor;
 592         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 593                                                 NULL);
 594         if (err) {
 595                 dev_err(dev, "%s: Unable to start governor for the device\n",
 596                         __func__);
 597                 goto err_init;
 598         }
 599         mutex_unlock(&devfreq_list_lock);
 600
 601         return devfreq;
 602
 603 err_init:
 604         list_del(&devfreq->node);
 605         mutex_unlock(&devfreq_list_lock);
 606
 607         device_unregister(&devfreq->dev);
 608 err_dev:
 609         if (devfreq)
 610                 kfree(devfreq);
 611 err_out:
 612         return ERR_PTR(err);
 613 }
 614 EXPORT_SYMBOL(devfreq_add_device);
 615
 616 /**
 617  * devfreq_remove_device() - Remove devfreq feature from a device.
 618  * @devfreq:    the devfreq instance to be removed
 619  *
 620  * The opposite of devfreq_add_device().
 621  */
 622 int devfreq_remove_device(struct devfreq *devfreq)
 623 {
 624         if (!devfreq)
 625                 return -EINVAL;
 626
 627         device_unregister(&devfreq->dev);
 628
 629         return 0;
 630 }
 631 EXPORT_SYMBOL(devfreq_remove_device);
 632
 633 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 634 {
 635         struct devfreq **r = res;
 636
 637         if (WARN_ON(!r || !*r))
 638                 return 0;
 639
 640         return *r == data;
 641 }
 642
 643 static void devm_devfreq_dev_release(struct device *dev, void *res)
 644 {
 645         devfreq_remove_device(*(struct devfreq **)res);
 646 }
 647
 648 /**
 649  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 650  * @dev:        the device to add devfreq feature.
 651  * @profile:    device-specific profile to run devfreq.
 652  * @governor_name:      name of the policy to choose frequency.
 653  * @data:       private data for the governor. The devfreq framework does not
 654  *              touch this value.
 655  *
 656  * This function manages automatically the memory of devfreq device using device
 657  * resource management and simplify the free operation for memory of devfreq
 658  * device.
 659  */
 660 struct devfreq *devm_devfreq_add_device(struct device *dev,
 661                                         struct devfreq_dev_profile *profile,
 662                                         const char *governor_name,
 663                                         void *data)
 664 {
 665         struct devfreq **ptr, *devfreq;
 666
 667         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 668         if (!ptr)
 669                 return ERR_PTR(-ENOMEM);
 670
 671         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 672         if (IS_ERR(devfreq)) {
 673                 devres_free(ptr);
 674                 return devfreq;
 675         }
 676
 677         *ptr = devfreq;
 678         devres_add(dev, ptr);
 679
 680         return devfreq;
 681 }
 682 EXPORT_SYMBOL(devm_devfreq_add_device);
 683
 684 #ifdef CONFIG_OF
 685 /*
 686  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 687  * @dev - instance to the given device
 688  * @index - index into list of devfreq
 689  *
 690  * return the instance of devfreq device
 691  */
 692 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 693 {
 694         struct device_node *node;
 695         struct devfreq *devfreq;
 696
 697         if (!dev)
 698                 return ERR_PTR(-EINVAL);
 699
 700         if (!dev->of_node)
 701                 return ERR_PTR(-EINVAL);
 702
 703         node = of_parse_phandle(dev->of_node, "devfreq", index);
 704         if (!node)
 705                 return ERR_PTR(-ENODEV);
 706
 707         mutex_lock(&devfreq_list_lock);
 708         list_for_each_entry(devfreq, &devfreq_list, node) {
 709                 if (devfreq->dev.parent
 710                         && devfreq->dev.parent->of_node == node) {
 711                         mutex_unlock(&devfreq_list_lock);
 712                         of_node_put(node);
 713                         return devfreq;
 714                 }
 715         }
 716         mutex_unlock(&devfreq_list_lock);
 717         of_node_put(node);
 718
 719         return ERR_PTR(-EPROBE_DEFER);
 720 }
 721 #else
 722 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 723 {
 724         return ERR_PTR(-ENODEV);
 725 }
 726 #endif /* CONFIG_OF */
 727 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 728
 729 /**
 730  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 731  * @dev:        the device to add devfreq feature.
 732  * @devfreq:    the devfreq instance to be removed
 733  */
 734 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 735 {
 736         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 737                                devm_devfreq_dev_match, devfreq));
 738 }
 739 EXPORT_SYMBOL(devm_devfreq_remove_device);
 740
 741 /**
 742  * devfreq_suspend_device() - Suspend devfreq of a device.
 743  * @devfreq: the devfreq instance to be suspended
 744  *
 745  * This function is intended to be called by the pm callbacks
 746  * (e.g., runtime_suspend, suspend) of the device driver that
 747  * holds the devfreq.
 748  */
 749 int devfreq_suspend_device(struct devfreq *devfreq)
 750 {
 751         if (!devfreq)
 752                 return -EINVAL;
 753
 754         if (!devfreq->governor)
 755                 return 0;
 756
 757         return devfreq->governor->event_handler(devfreq,
 758                                 DEVFREQ_GOV_SUSPEND, NULL);
 759 }
 760 EXPORT_SYMBOL(devfreq_suspend_device);
 761
 762 /**
 763  * devfreq_resume_device() - Resume devfreq of a device.
 764  * @devfreq: the devfreq instance to be resumed
 765  *
 766  * This function is intended to be called by the pm callbacks
 767  * (e.g., runtime_resume, resume) of the device driver that
 768  * holds the devfreq.
 769  */
 770 int devfreq_resume_device(struct devfreq *devfreq)
 771 {
 772         if (!devfreq)
 773                 return -EINVAL;
 774
 775         if (!devfreq->governor)
 776                 return 0;
 777
 778         return devfreq->governor->event_handler(devfreq,
 779                                 DEVFREQ_GOV_RESUME, NULL);
 780 }
 781 EXPORT_SYMBOL(devfreq_resume_device);
 782
 783 /**
 784  * devfreq_add_governor() - Add devfreq governor
 785  * @governor:   the devfreq governor to be added
 786  */
 787 int devfreq_add_governor(struct devfreq_governor *governor)
 788 {
 789         struct devfreq_governor *g;
 790         struct devfreq *devfreq;
 791         int err = 0;
 792
 793         if (!governor) {
 794                 pr_err("%s: Invalid parameters.\n", __func__);
 795                 return -EINVAL;
 796         }
 797
 798         mutex_lock(&devfreq_list_lock);
 799         g = find_devfreq_governor(governor->name);
 800         if (!IS_ERR(g)) {
 801                 pr_err("%s: governor %s already registered\n", __func__,
 802                        g->name);
 803                 err = -EINVAL;
 804                 goto err_out;
 805         }
 806
 807         list_add(&governor->node, &devfreq_governor_list);
 808
 809         list_for_each_entry(devfreq, &devfreq_list, node) {
 810                 int ret = 0;
 811                 struct device *dev = devfreq->dev.parent;
 812
 813                 if (!strncmp(devfreq->governor_name, governor->name,
 814                              DEVFREQ_NAME_LEN)) {
 815                         /* The following should never occur */
 816                         if (devfreq->governor) {
 817                                 dev_warn(dev,
 818                                          "%s: Governor %s already present\n",
 819                                          __func__, devfreq->governor->name);
 820                                 ret = devfreq->governor->event_handler(devfreq,
 821                                                         DEVFREQ_GOV_STOP, NULL);
 822                                 if (ret) {
 823                                         dev_warn(dev,
 824                                                  "%s: Governor %s stop = %d\n",
 825                                                  __func__,
 826                                                  devfreq->governor->name, ret);
 827                                 }
 828                                 /* Fall through */
 829                         }
 830                         devfreq->governor = governor;
 831                         ret = devfreq->governor->event_handler(devfreq,
 832                                                 DEVFREQ_GOV_START, NULL);
 833                         if (ret) {
 834                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 835                                          __func__, devfreq->governor->name,
 836                                          ret);
 837                         }
 838                 }
 839         }
 840
 841 err_out:
 842         mutex_unlock(&devfreq_list_lock);
 843
 844         return err;
 845 }
 846 EXPORT_SYMBOL(devfreq_add_governor);
 847
 848 /**
 849  * devfreq_remove_governor() - Remove devfreq feature from a device.
 850  * @governor:   the devfreq governor to be removed
 851  */
 852 int devfreq_remove_governor(struct devfreq_governor *governor)
 853 {
 854         struct devfreq_governor *g;
 855         struct devfreq *devfreq;
 856         int err = 0;
 857
 858         if (!governor) {
 859                 pr_err("%s: Invalid parameters.\n", __func__);
 860                 return -EINVAL;
 861         }
 862
 863         mutex_lock(&devfreq_list_lock);
 864         g = find_devfreq_governor(governor->name);
 865         if (IS_ERR(g)) {
 866                 pr_err("%s: governor %s not registered\n", __func__,
 867                        governor->name);
 868                 err = PTR_ERR(g);
 869                 goto err_out;
 870         }
 871         list_for_each_entry(devfreq, &devfreq_list, node) {
 872                 int ret;
 873                 struct device *dev = devfreq->dev.parent;
 874
 875                 if (!strncmp(devfreq->governor_name, governor->name,
 876                              DEVFREQ_NAME_LEN)) {
 877                         /* we should have a devfreq governor! */
 878                         if (!devfreq->governor) {
 879                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 880                                          __func__, governor->name);
 881                                 continue;
 882                                 /* Fall through */
 883                         }
 884                         ret = devfreq->governor->event_handler(devfreq,
 885                                                 DEVFREQ_GOV_STOP, NULL);
 886                         if (ret) {
 887                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 888                                          __func__, devfreq->governor->name,
 889                                          ret);
 890                         }
 891                         devfreq->governor = NULL;
 892                 }
 893         }
 894
 895         list_del(&governor->node);
 896 err_out:
 897         mutex_unlock(&devfreq_list_lock);
 898
 899         return err;
 900 }
 901 EXPORT_SYMBOL(devfreq_remove_governor);
 902
 903 static ssize_t name_show(struct device *dev,
 904                         struct device_attribute *attr, char *buf)
 905 {
 906         struct devfreq *devfreq = to_devfreq(dev);
 907         return sprintf(buf, "%s\n", dev_name(devfreq->dev.parent));
 908 }
 909 static DEVICE_ATTR_RO(name);
 910
 911 static ssize_t governor_show(struct device *dev,
 912                              struct device_attribute *attr, char *buf)
 913 {
 914         if (!to_devfreq(dev)->governor)
 915                 return -EINVAL;
 916
 917         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 918 }
 919
 920 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 921                               const char *buf, size_t count)
 922 {
 923         struct devfreq *df = to_devfreq(dev);
 924         int ret;
 925         char str_governor[DEVFREQ_NAME_LEN + 1];
 926         struct devfreq_governor *governor;
 927
 928         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 929         if (ret != 1)
 930                 return -EINVAL;
 931
 932         mutex_lock(&devfreq_list_lock);
 933         governor = find_devfreq_governor(str_governor);
 934         if (IS_ERR(governor)) {
 935                 ret = PTR_ERR(governor);
 936                 goto out;
 937         }
 938         if (df->governor == governor) {
 939                 ret = 0;
 940                 goto out;
 941         } else if ((df->governor && df->governor->immutable) ||
 942                                         governor->immutable) {
 943                 ret = -EINVAL;
 944                 goto out;
 945         }
 946
 947         if (df->governor) {
 948                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
 949                 if (ret) {
 950                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
 951                                  __func__, df->governor->name, ret);
 952                         goto out;
 953                 }
 954         }
 955         df->governor = governor;
 956         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
 957         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
 958         if (ret)
 959                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
 960                          __func__, df->governor->name, ret);
 961 out:
 962         mutex_unlock(&devfreq_list_lock);
 963
 964         if (!ret)
 965                 ret = count;
 966         return ret;
 967 }
 968 static DEVICE_ATTR_RW(governor);
 969
 970 static ssize_t available_governors_show(struct device *d,
 971                                         struct device_attribute *attr,
 972                                         char *buf)
 973 {
 974         struct devfreq *df = to_devfreq(d);
 975         ssize_t count = 0;
 976
 977         mutex_lock(&devfreq_list_lock);
 978
 979         /*
 980          * The devfreq with immutable governor (e.g., passive) shows
 981          * only own governor.
 982          */
 983         if (df->governor && df->governor->immutable) {
 984                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
 985                                    "%s ", df->governor_name);
 986         /*
 987          * The devfreq device shows the registered governor except for
 988          * immutable governors such as passive governor .
 989          */
 990         } else {
 991                 struct devfreq_governor *governor;
 992
 993                 list_for_each_entry(governor, &devfreq_governor_list, node) {
 994                         if (governor->immutable)
 995                                 continue;
 996                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
 997                                            "%s ", governor->name);
 998                 }
 999         }
1000
1001         mutex_unlock(&devfreq_list_lock);
1002
1003         /* Truncate the trailing space */
1004         if (count)
1005                 count--;
1006
1007         count += sprintf(&buf[count], "\n");
1008
1009         return count;
1010 }
1011 static DEVICE_ATTR_RO(available_governors);
1012
1013 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1014                              char *buf)
1015 {
1016         unsigned long freq;
1017         struct devfreq *devfreq = to_devfreq(dev);
1018
1019         if (devfreq->profile->get_cur_freq &&
1020                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1021                 return sprintf(buf, "%lu\n", freq);
1022
1023         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1024 }
1025 static DEVICE_ATTR_RO(cur_freq);
1026
1027 static ssize_t target_freq_show(struct device *dev,
1028                                 struct device_attribute *attr, char *buf)
1029 {
1030         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1031 }
1032 static DEVICE_ATTR_RO(target_freq);
1033
1034 static ssize_t polling_interval_show(struct device *dev,
1035                                      struct device_attribute *attr, char *buf)
1036 {
1037         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1038 }
1039
1040 static ssize_t polling_interval_store(struct device *dev,
1041                                       struct device_attribute *attr,
1042                                       const char *buf, size_t count)
1043 {
1044         struct devfreq *df = to_devfreq(dev);
1045         unsigned int value;
1046         int ret;
1047
1048         if (!df->governor)
1049                 return -EINVAL;
1050
1051         ret = sscanf(buf, "%u", &value);
1052         if (ret != 1)
1053                 return -EINVAL;
1054
1055         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1056         ret = count;
1057
1058         return ret;
1059 }
1060 static DEVICE_ATTR_RW(polling_interval);
1061
1062 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1063                               const char *buf, size_t count)
1064 {
1065         struct devfreq *df = to_devfreq(dev);
1066         unsigned long value;
1067         int ret;
1068         unsigned long max;
1069
1070         ret = sscanf(buf, "%lu", &value);
1071         if (ret != 1)
1072                 return -EINVAL;
1073
1074         mutex_lock(&df->lock);
1075         max = df->max_freq;
1076         if (value && max && value > max) {
1077                 ret = -EINVAL;
1078                 goto unlock;
1079         }
1080
1081         df->min_freq = value;
1082         update_devfreq(df);
1083         ret = count;
1084 unlock:
1085         mutex_unlock(&df->lock);
1086         return ret;
1087 }
1088
1089 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1090                               const char *buf, size_t count)
1091 {
1092         struct devfreq *df = to_devfreq(dev);
1093         unsigned long value;
1094         int ret;
1095         unsigned long min;
1096
1097         ret = sscanf(buf, "%lu", &value);
1098         if (ret != 1)
1099                 return -EINVAL;
1100
1101         mutex_lock(&df->lock);
1102         min = df->min_freq;
1103         if (value && min && value < min) {
1104                 ret = -EINVAL;
1105                 goto unlock;
1106         }
1107
1108         df->max_freq = value;
1109         update_devfreq(df);
1110         ret = count;
1111 unlock:
1112         mutex_unlock(&df->lock);
1113         return ret;
1114 }
1115
1116 #define show_one(name)                                          \
1117 static ssize_t name##_show                                      \
1118 (struct device *dev, struct device_attribute *attr, char *buf)  \
1119 {                                                               \
1120         return sprintf(buf, "%lu\n", to_devfreq(dev)->name);    \
1121 }
1122 show_one(min_freq);
1123 show_one(max_freq);
1124
1125 static DEVICE_ATTR_RW(min_freq);
1126 static DEVICE_ATTR_RW(max_freq);
1127
1128 static ssize_t available_frequencies_show(struct device *d,
1129                                           struct device_attribute *attr,
1130                                           char *buf)
1131 {
1132         struct devfreq *df = to_devfreq(d);
1133         struct device *dev = df->dev.parent;
1134         struct dev_pm_opp *opp;
1135         ssize_t count = 0;
1136         unsigned long freq = 0;
1137
1138         do {
1139                 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1140                 if (IS_ERR(opp))
1141                         break;
1142
1143                 dev_pm_opp_put(opp);
1144                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1145                                    "%lu ", freq);
1146                 freq++;
1147         } while (1);
1148
1149         /* Truncate the trailing space */
1150         if (count)
1151                 count--;
1152
1153         count += sprintf(&buf[count], "\n");
1154
1155         return count;
1156 }
1157 static DEVICE_ATTR_RO(available_frequencies);
1158
1159 static ssize_t trans_stat_show(struct device *dev,
1160                                struct device_attribute *attr, char *buf)
1161 {
1162         struct devfreq *devfreq = to_devfreq(dev);
1163         ssize_t len;
1164         int i, j;
1165         unsigned int max_state = devfreq->profile->max_state;
1166
1167         if (max_state == 0)
1168                 return sprintf(buf, "Not Supported.\n");
1169
1170         mutex_lock(&devfreq->lock);
1171         if (!devfreq->stop_polling &&
1172                         devfreq_update_status(devfreq, devfreq->previous_freq)) {
1173                 mutex_unlock(&devfreq->lock);
1174                 return 0;
1175         }
1176         mutex_unlock(&devfreq->lock);
1177
1178         len = sprintf(buf, "     From  :   To\n");
1179         len += sprintf(buf + len, "           :");
1180         for (i = 0; i < max_state; i++)
1181                 len += sprintf(buf + len, "%10lu",
1182                                 devfreq->profile->freq_table[i]);
1183
1184         len += sprintf(buf + len, "   time(ms)\n");
1185
1186         for (i = 0; i < max_state; i++) {
1187                 if (devfreq->profile->freq_table[i]
1188                                         == devfreq->previous_freq) {
1189                         len += sprintf(buf + len, "*");
1190                 } else {
1191                         len += sprintf(buf + len, " ");
1192                 }
1193                 len += sprintf(buf + len, "%10lu:",
1194                                 devfreq->profile->freq_table[i]);
1195                 for (j = 0; j < max_state; j++)
1196                         len += sprintf(buf + len, "%10u",
1197                                 devfreq->trans_table[(i * max_state) + j]);
1198                 len += sprintf(buf + len, "%10u\n",
1199                         jiffies_to_msecs(devfreq->time_in_state[i]));
1200         }
1201
1202         len += sprintf(buf + len, "Total transition : %u\n",
1203                                         devfreq->total_trans);
1204         return len;
1205 }
1206 static DEVICE_ATTR_RO(trans_stat);
1207
1208 static struct attribute *devfreq_attrs[] = {
1209         &dev_attr_name.attr,
1210         &dev_attr_governor.attr,
1211         &dev_attr_available_governors.attr,
1212         &dev_attr_cur_freq.attr,
1213         &dev_attr_available_frequencies.attr,
1214         &dev_attr_target_freq.attr,
1215         &dev_attr_polling_interval.attr,
1216         &dev_attr_min_freq.attr,
1217         &dev_attr_max_freq.attr,
1218         &dev_attr_trans_stat.attr,
1219         NULL,
1220 };
1221 ATTRIBUTE_GROUPS(devfreq);
1222
1223 static int __init devfreq_init(void)
1224 {
1225         devfreq_class = class_create(THIS_MODULE, "devfreq");
1226         if (IS_ERR(devfreq_class)) {
1227                 pr_err("%s: couldn't create class\n", __FILE__);
1228                 return PTR_ERR(devfreq_class);
1229         }
1230
1231         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1232         if (!devfreq_wq) {
1233                 class_destroy(devfreq_class);
1234                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1235                 return -ENOMEM;
1236         }
1237         devfreq_class->dev_groups = devfreq_groups;
1238
1239         return 0;
1240 }
1241 subsys_initcall(devfreq_init);
1242
1243 /*
1244  * The following are helper functions for devfreq user device drivers with
1245  * OPP framework.
1246  */
1247
1248 /**
1249  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1250  *                           freq value given to target callback.
1251  * @dev:        The devfreq user device. (parent of devfreq)
1252  * @freq:       The frequency given to target function
1253  * @flags:      Flags handed from devfreq framework.
1254  *
1255  * The callers are required to call dev_pm_opp_put() for the returned OPP after
1256  * use.
1257  */
1258 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1259                                            unsigned long *freq,
1260                                            u32 flags)
1261 {
1262         struct dev_pm_opp *opp;
1263
1264         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1265                 /* The freq is an upper bound. opp should be lower */
1266                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1267
1268                 /* If not available, use the closest opp */
1269                 if (opp == ERR_PTR(-ERANGE))
1270                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1271         } else {
1272                 /* The freq is an lower bound. opp should be higher */
1273                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1274
1275                 /* If not available, use the closest opp */
1276                 if (opp == ERR_PTR(-ERANGE))
1277                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1278         }
1279
1280         return opp;
1281 }
1282 EXPORT_SYMBOL(devfreq_recommended_opp);
1283
1284 /**
1285  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1286  *                                 for any changes in the OPP availability
1287  *                                 changes
1288  * @dev:        The devfreq user device. (parent of devfreq)
1289  * @devfreq:    The devfreq object.
1290  */
1291 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1292 {
1293         return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1294 }
1295 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1296
1297 /**
1298  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1299  *                                   notified for any changes in the OPP
1300  *                                   availability changes anymore.
1301  * @dev:        The devfreq user device. (parent of devfreq)
1302  * @devfreq:    The devfreq object.
1303  *
1304  * At exit() callback of devfreq_dev_profile, this must be included if
1305  * devfreq_recommended_opp is used.
1306  */
1307 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1308 {
1309         return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1310 }
1311 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1312
1313 static void devm_devfreq_opp_release(struct device *dev, void *res)
1314 {
1315         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1316 }
1317
1318 /**
1319  * devm_ devfreq_register_opp_notifier()
1320  *              - Resource-managed devfreq_register_opp_notifier()
1321  * @dev:        The devfreq user device. (parent of devfreq)
1322  * @devfreq:    The devfreq object.
1323  */
1324 int devm_devfreq_register_opp_notifier(struct device *dev,
1325                                        struct devfreq *devfreq)
1326 {
1327         struct devfreq **ptr;
1328         int ret;
1329
1330         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1331         if (!ptr)
1332                 return -ENOMEM;
1333
1334         ret = devfreq_register_opp_notifier(dev, devfreq);
1335         if (ret) {
1336                 devres_free(ptr);
1337                 return ret;
1338         }
1339
1340         *ptr = devfreq;
1341         devres_add(dev, ptr);
1342
1343         return 0;
1344 }
1345 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1346
1347 /**
1348  * devm_devfreq_unregister_opp_notifier()
1349  *              - Resource-managed devfreq_unregister_opp_notifier()
1350  * @dev:        The devfreq user device. (parent of devfreq)
1351  * @devfreq:    The devfreq object.
1352  */
1353 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1354                                          struct devfreq *devfreq)
1355 {
1356         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1357                                devm_devfreq_dev_match, devfreq));
1358 }
1359 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1360
1361 /**
1362  * devfreq_register_notifier() - Register a driver with devfreq
1363  * @devfreq:    The devfreq object.
1364  * @nb:         The notifier block to register.
1365  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1366  */
1367 int devfreq_register_notifier(struct devfreq *devfreq,
1368                                 struct notifier_block *nb,
1369                                 unsigned int list)
1370 {
1371         int ret = 0;
1372
1373         if (!devfreq)
1374                 return -EINVAL;
1375
1376         switch (list) {
1377         case DEVFREQ_TRANSITION_NOTIFIER:
1378                 ret = srcu_notifier_chain_register(
1379                                 &devfreq->transition_notifier_list, nb);
1380                 break;
1381         default:
1382                 ret = -EINVAL;
1383         }
1384
1385         return ret;
1386 }
1387 EXPORT_SYMBOL(devfreq_register_notifier);
1388
1389 /*
1390  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1391  * @devfreq:    The devfreq object.
1392  * @nb:         The notifier block to be unregistered.
1393  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1394  */
1395 int devfreq_unregister_notifier(struct devfreq *devfreq,
1396                                 struct notifier_block *nb,
1397                                 unsigned int list)
1398 {
1399         int ret = 0;
1400
1401         if (!devfreq)
1402                 return -EINVAL;
1403
1404         switch (list) {
1405         case DEVFREQ_TRANSITION_NOTIFIER:
1406                 ret = srcu_notifier_chain_unregister(
1407                                 &devfreq->transition_notifier_list, nb);
1408                 break;
1409         default:
1410                 ret = -EINVAL;
1411         }
1412
1413         return ret;
1414 }
1415 EXPORT_SYMBOL(devfreq_unregister_notifier);
1416
1417 struct devfreq_notifier_devres {
1418         struct devfreq *devfreq;
1419         struct notifier_block *nb;
1420         unsigned int list;
1421 };
1422
1423 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1424 {
1425         struct devfreq_notifier_devres *this = res;
1426
1427         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1428 }
1429
1430 /**
1431  * devm_devfreq_register_notifier()
1432         - Resource-managed devfreq_register_notifier()
1433  * @dev:        The devfreq user device. (parent of devfreq)
1434  * @devfreq:    The devfreq object.
1435  * @nb:         The notifier block to be unregistered.
1436  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1437  */
1438 int devm_devfreq_register_notifier(struct device *dev,
1439                                 struct devfreq *devfreq,
1440                                 struct notifier_block *nb,
1441                                 unsigned int list)
1442 {
1443         struct devfreq_notifier_devres *ptr;
1444         int ret;
1445
1446         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1447                                 GFP_KERNEL);
1448         if (!ptr)
1449                 return -ENOMEM;
1450
1451         ret = devfreq_register_notifier(devfreq, nb, list);
1452         if (ret) {
1453                 devres_free(ptr);
1454                 return ret;
1455         }
1456
1457         ptr->devfreq = devfreq;
1458         ptr->nb = nb;
1459         ptr->list = list;
1460         devres_add(dev, ptr);
1461
1462         return 0;
1463 }
1464 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1465
1466 /**
1467  * devm_devfreq_unregister_notifier()
1468         - Resource-managed devfreq_unregister_notifier()
1469  * @dev:        The devfreq user device. (parent of devfreq)
1470  * @devfreq:    The devfreq object.
1471  * @nb:         The notifier block to be unregistered.
1472  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1473  */
1474 void devm_devfreq_unregister_notifier(struct device *dev,
1475                                 struct devfreq *devfreq,
1476                                 struct notifier_block *nb,
1477                                 unsigned int list)
1478 {
1479         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1480                                devm_devfreq_dev_match, devfreq));
1481 }
1482 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);