drivers/devfreq/devfreq.c

   1 /*
   2  * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
   3  *          for Non-CPU Devices.
   4  *
   5  * Copyright (C) 2011 Samsung Electronics
   6  *      MyungJoo Ham <myungjoo.ham@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/errno.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/export.h>
  19 #include <linux/slab.h>
  20 #include <linux/stat.h>
  21 #include <linux/pm_opp.h>
  22 #include <linux/devfreq.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/list.h>
  26 #include <linux/printk.h>
  27 #include <linux/hrtimer.h>
  28 #include <linux/of.h>
  29 #include "governor.h"
  30
  31 static struct class *devfreq_class;
  32
  33 /*
  34  * devfreq core provides delayed work based load monitoring helper
  35  * functions. Governors can use these or can implement their own
  36  * monitoring mechanism.
  37  */
  38 static struct workqueue_struct *devfreq_wq;
  39
  40 /* The list of all device-devfreq governors */
  41 static LIST_HEAD(devfreq_governor_list);
  42 /* The list of all device-devfreq */
  43 static LIST_HEAD(devfreq_list);
  44 static DEFINE_MUTEX(devfreq_list_lock);
  45
  46 /**
  47  * find_device_devfreq() - find devfreq struct using device pointer
  48  * @dev:        device pointer used to lookup device devfreq.
  49  *
  50  * Search the list of device devfreqs and return the matched device's
  51  * devfreq info. devfreq_list_lock should be held by the caller.
  52  */
  53 static struct devfreq *find_device_devfreq(struct device *dev)
  54 {
  55         struct devfreq *tmp_devfreq;
  56
  57         if (IS_ERR_OR_NULL(dev)) {
  58                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  59                 return ERR_PTR(-EINVAL);
  60         }
  61         WARN(!mutex_is_locked(&devfreq_list_lock),
  62              "devfreq_list_lock must be locked.");
  63
  64         list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  65                 if (tmp_devfreq->dev.parent == dev)
  66                         return tmp_devfreq;
  67         }
  68
  69         return ERR_PTR(-ENODEV);
  70 }
  71
  72 /**
  73  * devfreq_get_freq_level() - Lookup freq_table for the frequency
  74  * @devfreq:    the devfreq instance
  75  * @freq:       the target frequency
  76  */
  77 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
  78 {
  79         int lev;
  80
  81         for (lev = 0; lev < devfreq->profile->max_state; lev++)
  82                 if (freq == devfreq->profile->freq_table[lev])
  83                         return lev;
  84
  85         return -EINVAL;
  86 }
  87
  88 /**
  89  * devfreq_set_freq_table() - Initialize freq_table for the frequency
  90  * @devfreq:    the devfreq instance
  91  */
  92 static void devfreq_set_freq_table(struct devfreq *devfreq)
  93 {
  94         struct devfreq_dev_profile *profile = devfreq->profile;
  95         struct dev_pm_opp *opp;
  96         unsigned long freq;
  97         int i, count;
  98
  99         /* Initialize the freq_table from OPP table */
 100         count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 101         if (count <= 0)
 102                 return;
 103
 104         profile->max_state = count;
 105         profile->freq_table = devm_kcalloc(devfreq->dev.parent,
 106                                         profile->max_state,
 107                                         sizeof(*profile->freq_table),
 108                                         GFP_KERNEL);
 109         if (!profile->freq_table) {
 110                 profile->max_state = 0;
 111                 return;
 112         }
 113
 114         rcu_read_lock();
 115         for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
 116                 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 117                 if (IS_ERR(opp)) {
 118                         devm_kfree(devfreq->dev.parent, profile->freq_table);
 119                         profile->max_state = 0;
 120                         rcu_read_unlock();
 121                         return;
 122                 }
 123                 profile->freq_table[i] = freq;
 124         }
 125         rcu_read_unlock();
 126 }
 127
 128 /**
 129  * devfreq_update_status() - Update statistics of devfreq behavior
 130  * @devfreq:    the devfreq instance
 131  * @freq:       the update target frequency
 132  */
 133 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 134 {
 135         int lev, prev_lev, ret = 0;
 136         unsigned long cur_time;
 137
 138         cur_time = jiffies;
 139
 140         /* Immediately exit if previous_freq is not initialized yet. */
 141         if (!devfreq->previous_freq)
 142                 goto out;
 143
 144         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 145         if (prev_lev < 0) {
 146                 ret = prev_lev;
 147                 goto out;
 148         }
 149
 150         devfreq->time_in_state[prev_lev] +=
 151                          cur_time - devfreq->last_stat_updated;
 152
 153         lev = devfreq_get_freq_level(devfreq, freq);
 154         if (lev < 0) {
 155                 ret = lev;
 156                 goto out;
 157         }
 158
 159         if (lev != prev_lev) {
 160                 devfreq->trans_table[(prev_lev *
 161                                 devfreq->profile->max_state) + lev]++;
 162                 devfreq->total_trans++;
 163         }
 164
 165 out:
 166         devfreq->last_stat_updated = cur_time;
 167         return ret;
 168 }
 169 EXPORT_SYMBOL(devfreq_update_status);
 170
 171 /**
 172  * find_devfreq_governor() - find devfreq governor from name
 173  * @name:       name of the governor
 174  *
 175  * Search the list of devfreq governors and return the matched
 176  * governor's pointer. devfreq_list_lock should be held by the caller.
 177  */
 178 static struct devfreq_governor *find_devfreq_governor(const char *name)
 179 {
 180         struct devfreq_governor *tmp_governor;
 181
 182         if (IS_ERR_OR_NULL(name)) {
 183                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 184                 return ERR_PTR(-EINVAL);
 185         }
 186         WARN(!mutex_is_locked(&devfreq_list_lock),
 187              "devfreq_list_lock must be locked.");
 188
 189         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 190                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 191                         return tmp_governor;
 192         }
 193
 194         return ERR_PTR(-ENODEV);
 195 }
 196
 197 static int devfreq_notify_transition(struct devfreq *devfreq,
 198                 struct devfreq_freqs *freqs, unsigned int state)
 199 {
 200         if (!devfreq)
 201                 return -EINVAL;
 202
 203         switch (state) {
 204         case DEVFREQ_PRECHANGE:
 205                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 206                                 DEVFREQ_PRECHANGE, freqs);
 207                 break;
 208
 209         case DEVFREQ_POSTCHANGE:
 210                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 211                                 DEVFREQ_POSTCHANGE, freqs);
 212                 break;
 213         default:
 214                 return -EINVAL;
 215         }
 216
 217         return 0;
 218 }
 219
 220 /* Load monitoring helper functions for governors use */
 221
 222 /**
 223  * update_devfreq() - Reevaluate the device and configure frequency.
 224  * @devfreq:    the devfreq instance.
 225  *
 226  * Note: Lock devfreq->lock before calling update_devfreq
 227  *       This function is exported for governors.
 228  */
 229 int update_devfreq(struct devfreq *devfreq)
 230 {
 231         struct devfreq_freqs freqs;
 232         unsigned long freq, cur_freq;
 233         int err = 0;
 234         u32 flags = 0;
 235
 236         if (!mutex_is_locked(&devfreq->lock)) {
 237                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 238                 return -EINVAL;
 239         }
 240
 241         if (!devfreq->governor)
 242                 return -EINVAL;
 243
 244         /* Reevaluate the proper frequency */
 245         err = devfreq->governor->get_target_freq(devfreq, &freq);
 246         if (err)
 247                 return err;
 248
 249         /*
 250          * Adjust the frequency with user freq and QoS.
 251          *
 252          * List from the highest priority
 253          * max_freq
 254          * min_freq
 255          */
 256
 257         if (devfreq->min_freq && freq < devfreq->min_freq) {
 258                 freq = devfreq->min_freq;
 259                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 260         }
 261         if (devfreq->max_freq && freq > devfreq->max_freq) {
 262                 freq = devfreq->max_freq;
 263                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 264         }
 265
 266         if (devfreq->profile->get_cur_freq)
 267                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 268         else
 269                 cur_freq = devfreq->previous_freq;
 270
 271         freqs.old = cur_freq;
 272         freqs.new = freq;
 273         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 274
 275         err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 276         if (err) {
 277                 freqs.new = cur_freq;
 278                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 279                 return err;
 280         }
 281
 282         freqs.new = freq;
 283         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 284
 285         if (devfreq->profile->freq_table)
 286                 if (devfreq_update_status(devfreq, freq))
 287                         dev_err(&devfreq->dev,
 288                                 "Couldn't update frequency transition information.\n");
 289
 290         devfreq->previous_freq = freq;
 291         return err;
 292 }
 293 EXPORT_SYMBOL(update_devfreq);
 294
 295 /**
 296  * devfreq_monitor() - Periodically poll devfreq objects.
 297  * @work:       the work struct used to run devfreq_monitor periodically.
 298  *
 299  */
 300 static void devfreq_monitor(struct work_struct *work)
 301 {
 302         int err;
 303         struct devfreq *devfreq = container_of(work,
 304                                         struct devfreq, work.work);
 305
 306         mutex_lock(&devfreq->lock);
 307         err = update_devfreq(devfreq);
 308         if (err)
 309                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 310
 311         queue_delayed_work(devfreq_wq, &devfreq->work,
 312                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 313         mutex_unlock(&devfreq->lock);
 314 }
 315
 316 /**
 317  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 318  * @devfreq:    the devfreq instance.
 319  *
 320  * Helper function for starting devfreq device load monitoing. By
 321  * default delayed work based monitoring is supported. Function
 322  * to be called from governor in response to DEVFREQ_GOV_START
 323  * event when device is added to devfreq framework.
 324  */
 325 void devfreq_monitor_start(struct devfreq *devfreq)
 326 {
 327         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 328         if (devfreq->profile->polling_ms)
 329                 queue_delayed_work(devfreq_wq, &devfreq->work,
 330                         msecs_to_jiffies(devfreq->profile->polling_ms));
 331 }
 332 EXPORT_SYMBOL(devfreq_monitor_start);
 333
 334 /**
 335  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 336  * @devfreq:    the devfreq instance.
 337  *
 338  * Helper function to stop devfreq device load monitoing. Function
 339  * to be called from governor in response to DEVFREQ_GOV_STOP
 340  * event when device is removed from devfreq framework.
 341  */
 342 void devfreq_monitor_stop(struct devfreq *devfreq)
 343 {
 344         cancel_delayed_work_sync(&devfreq->work);
 345 }
 346 EXPORT_SYMBOL(devfreq_monitor_stop);
 347
 348 /**
 349  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 350  * @devfreq:    the devfreq instance.
 351  *
 352  * Helper function to suspend devfreq device load monitoing. Function
 353  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 354  * event or when polling interval is set to zero.
 355  *
 356  * Note: Though this function is same as devfreq_monitor_stop(),
 357  * intentionally kept separate to provide hooks for collecting
 358  * transition statistics.
 359  */
 360 void devfreq_monitor_suspend(struct devfreq *devfreq)
 361 {
 362         mutex_lock(&devfreq->lock);
 363         if (devfreq->stop_polling) {
 364                 mutex_unlock(&devfreq->lock);
 365                 return;
 366         }
 367
 368         devfreq_update_status(devfreq, devfreq->previous_freq);
 369         devfreq->stop_polling = true;
 370         mutex_unlock(&devfreq->lock);
 371         cancel_delayed_work_sync(&devfreq->work);
 372 }
 373 EXPORT_SYMBOL(devfreq_monitor_suspend);
 374
 375 /**
 376  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 377  * @devfreq:    the devfreq instance.
 378  *
 379  * Helper function to resume devfreq device load monitoing. Function
 380  * to be called from governor in response to DEVFREQ_GOV_RESUME
 381  * event or when polling interval is set to non-zero.
 382  */
 383 void devfreq_monitor_resume(struct devfreq *devfreq)
 384 {
 385         unsigned long freq;
 386
 387         mutex_lock(&devfreq->lock);
 388         if (!devfreq->stop_polling)
 389                 goto out;
 390
 391         if (!delayed_work_pending(&devfreq->work) &&
 392                         devfreq->profile->polling_ms)
 393                 queue_delayed_work(devfreq_wq, &devfreq->work,
 394                         msecs_to_jiffies(devfreq->profile->polling_ms));
 395
 396         devfreq->last_stat_updated = jiffies;
 397         devfreq->stop_polling = false;
 398
 399         if (devfreq->profile->get_cur_freq &&
 400                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 401                 devfreq->previous_freq = freq;
 402
 403 out:
 404         mutex_unlock(&devfreq->lock);
 405 }
 406 EXPORT_SYMBOL(devfreq_monitor_resume);
 407
 408 /**
 409  * devfreq_interval_update() - Update device devfreq monitoring interval
 410  * @devfreq:    the devfreq instance.
 411  * @delay:      new polling interval to be set.
 412  *
 413  * Helper function to set new load monitoring polling interval. Function
 414  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 415  */
 416 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 417 {
 418         unsigned int cur_delay = devfreq->profile->polling_ms;
 419         unsigned int new_delay = *delay;
 420
 421         mutex_lock(&devfreq->lock);
 422         devfreq->profile->polling_ms = new_delay;
 423
 424         if (devfreq->stop_polling)
 425                 goto out;
 426
 427         /* if new delay is zero, stop polling */
 428         if (!new_delay) {
 429                 mutex_unlock(&devfreq->lock);
 430                 cancel_delayed_work_sync(&devfreq->work);
 431                 return;
 432         }
 433
 434         /* if current delay is zero, start polling with new delay */
 435         if (!cur_delay) {
 436                 queue_delayed_work(devfreq_wq, &devfreq->work,
 437                         msecs_to_jiffies(devfreq->profile->polling_ms));
 438                 goto out;
 439         }
 440
 441         /* if current delay is greater than new delay, restart polling */
 442         if (cur_delay > new_delay) {
 443                 mutex_unlock(&devfreq->lock);
 444                 cancel_delayed_work_sync(&devfreq->work);
 445                 mutex_lock(&devfreq->lock);
 446                 if (!devfreq->stop_polling)
 447                         queue_delayed_work(devfreq_wq, &devfreq->work,
 448                               msecs_to_jiffies(devfreq->profile->polling_ms));
 449         }
 450 out:
 451         mutex_unlock(&devfreq->lock);
 452 }
 453 EXPORT_SYMBOL(devfreq_interval_update);
 454
 455 /**
 456  * devfreq_notifier_call() - Notify that the device frequency requirements
 457  *                         has been changed out of devfreq framework.
 458  * @nb:         the notifier_block (supposed to be devfreq->nb)
 459  * @type:       not used
 460  * @devp:       not used
 461  *
 462  * Called by a notifier that uses devfreq->nb.
 463  */
 464 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 465                                  void *devp)
 466 {
 467         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 468         int ret;
 469
 470         mutex_lock(&devfreq->lock);
 471         ret = update_devfreq(devfreq);
 472         mutex_unlock(&devfreq->lock);
 473
 474         return ret;
 475 }
 476
 477 /**
 478  * _remove_devfreq() - Remove devfreq from the list and release its resources.
 479  * @devfreq:    the devfreq struct
 480  */
 481 static void _remove_devfreq(struct devfreq *devfreq)
 482 {
 483         mutex_lock(&devfreq_list_lock);
 484         if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
 485                 mutex_unlock(&devfreq_list_lock);
 486                 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
 487                 return;
 488         }
 489         list_del(&devfreq->node);
 490         mutex_unlock(&devfreq_list_lock);
 491
 492         if (devfreq->governor)
 493                 devfreq->governor->event_handler(devfreq,
 494                                                  DEVFREQ_GOV_STOP, NULL);
 495
 496         if (devfreq->profile->exit)
 497                 devfreq->profile->exit(devfreq->dev.parent);
 498
 499         mutex_destroy(&devfreq->lock);
 500         kfree(devfreq);
 501 }
 502
 503 /**
 504  * devfreq_dev_release() - Callback for struct device to release the device.
 505  * @dev:        the devfreq device
 506  *
 507  * This calls _remove_devfreq() if _remove_devfreq() is not called.
 508  */
 509 static void devfreq_dev_release(struct device *dev)
 510 {
 511         struct devfreq *devfreq = to_devfreq(dev);
 512
 513         _remove_devfreq(devfreq);
 514 }
 515
 516 /**
 517  * devfreq_add_device() - Add devfreq feature to the device
 518  * @dev:        the device to add devfreq feature.
 519  * @profile:    device-specific profile to run devfreq.
 520  * @governor_name:      name of the policy to choose frequency.
 521  * @data:       private data for the governor. The devfreq framework does not
 522  *              touch this value.
 523  */
 524 struct devfreq *devfreq_add_device(struct device *dev,
 525                                    struct devfreq_dev_profile *profile,
 526                                    const char *governor_name,
 527                                    void *data)
 528 {
 529         struct devfreq *devfreq;
 530         struct devfreq_governor *governor;
 531         int err = 0;
 532
 533         if (!dev || !profile || !governor_name) {
 534                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 535                 return ERR_PTR(-EINVAL);
 536         }
 537
 538         mutex_lock(&devfreq_list_lock);
 539         devfreq = find_device_devfreq(dev);
 540         mutex_unlock(&devfreq_list_lock);
 541         if (!IS_ERR(devfreq)) {
 542                 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
 543                 err = -EINVAL;
 544                 goto err_out;
 545         }
 546
 547         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 548         if (!devfreq) {
 549                 dev_err(dev, "%s: Unable to create devfreq for the device\n",
 550                         __func__);
 551                 err = -ENOMEM;
 552                 goto err_out;
 553         }
 554
 555         mutex_init(&devfreq->lock);
 556         mutex_lock(&devfreq->lock);
 557         devfreq->dev.parent = dev;
 558         devfreq->dev.class = devfreq_class;
 559         devfreq->dev.release = devfreq_dev_release;
 560         devfreq->profile = profile;
 561         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 562         devfreq->previous_freq = profile->initial_freq;
 563         devfreq->last_status.current_frequency = profile->initial_freq;
 564         devfreq->data = data;
 565         devfreq->nb.notifier_call = devfreq_notifier_call;
 566
 567         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 568                 mutex_unlock(&devfreq->lock);
 569                 devfreq_set_freq_table(devfreq);
 570                 mutex_lock(&devfreq->lock);
 571         }
 572
 573         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 574         err = device_register(&devfreq->dev);
 575         if (err) {
 576                 mutex_unlock(&devfreq->lock);
 577                 goto err_dev;
 578         }
 579
 580         devfreq->trans_table =  devm_kzalloc(&devfreq->dev, sizeof(unsigned int) *
 581                                                 devfreq->profile->max_state *
 582                                                 devfreq->profile->max_state,
 583                                                 GFP_KERNEL);
 584         devfreq->time_in_state = devm_kzalloc(&devfreq->dev, sizeof(unsigned long) *
 585                                                 devfreq->profile->max_state,
 586                                                 GFP_KERNEL);
 587         devfreq->last_stat_updated = jiffies;
 588
 589         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 590
 591         mutex_unlock(&devfreq->lock);
 592
 593         mutex_lock(&devfreq_list_lock);
 594         list_add(&devfreq->node, &devfreq_list);
 595
 596         governor = find_devfreq_governor(devfreq->governor_name);
 597         if (IS_ERR(governor)) {
 598                 dev_err(dev, "%s: Unable to find governor for the device\n",
 599                         __func__);
 600                 err = PTR_ERR(governor);
 601                 goto err_init;
 602         }
 603
 604         devfreq->governor = governor;
 605         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 606                                                 NULL);
 607         if (err) {
 608                 dev_err(dev, "%s: Unable to start governor for the device\n",
 609                         __func__);
 610                 goto err_init;
 611         }
 612         mutex_unlock(&devfreq_list_lock);
 613
 614         return devfreq;
 615
 616 err_init:
 617         list_del(&devfreq->node);
 618         mutex_unlock(&devfreq_list_lock);
 619
 620         device_unregister(&devfreq->dev);
 621 err_dev:
 622         if (devfreq)
 623                 kfree(devfreq);
 624 err_out:
 625         return ERR_PTR(err);
 626 }
 627 EXPORT_SYMBOL(devfreq_add_device);
 628
 629 /**
 630  * devfreq_remove_device() - Remove devfreq feature from a device.
 631  * @devfreq:    the devfreq instance to be removed
 632  *
 633  * The opposite of devfreq_add_device().
 634  */
 635 int devfreq_remove_device(struct devfreq *devfreq)
 636 {
 637         if (!devfreq)
 638                 return -EINVAL;
 639
 640         device_unregister(&devfreq->dev);
 641
 642         return 0;
 643 }
 644 EXPORT_SYMBOL(devfreq_remove_device);
 645
 646 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 647 {
 648         struct devfreq **r = res;
 649
 650         if (WARN_ON(!r || !*r))
 651                 return 0;
 652
 653         return *r == data;
 654 }
 655
 656 static void devm_devfreq_dev_release(struct device *dev, void *res)
 657 {
 658         devfreq_remove_device(*(struct devfreq **)res);
 659 }
 660
 661 /**
 662  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 663  * @dev:        the device to add devfreq feature.
 664  * @profile:    device-specific profile to run devfreq.
 665  * @governor_name:      name of the policy to choose frequency.
 666  * @data:       private data for the governor. The devfreq framework does not
 667  *              touch this value.
 668  *
 669  * This function manages automatically the memory of devfreq device using device
 670  * resource management and simplify the free operation for memory of devfreq
 671  * device.
 672  */
 673 struct devfreq *devm_devfreq_add_device(struct device *dev,
 674                                         struct devfreq_dev_profile *profile,
 675                                         const char *governor_name,
 676                                         void *data)
 677 {
 678         struct devfreq **ptr, *devfreq;
 679
 680         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 681         if (!ptr)
 682                 return ERR_PTR(-ENOMEM);
 683
 684         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 685         if (IS_ERR(devfreq)) {
 686                 devres_free(ptr);
 687                 return devfreq;
 688         }
 689
 690         *ptr = devfreq;
 691         devres_add(dev, ptr);
 692
 693         return devfreq;
 694 }
 695 EXPORT_SYMBOL(devm_devfreq_add_device);
 696
 697 #ifdef CONFIG_OF
 698 /*
 699  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 700  * @dev - instance to the given device
 701  * @index - index into list of devfreq
 702  *
 703  * return the instance of devfreq device
 704  */
 705 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 706 {
 707         struct device_node *node;
 708         struct devfreq *devfreq;
 709
 710         if (!dev)
 711                 return ERR_PTR(-EINVAL);
 712
 713         if (!dev->of_node)
 714                 return ERR_PTR(-EINVAL);
 715
 716         node = of_parse_phandle(dev->of_node, "devfreq", index);
 717         if (!node)
 718                 return ERR_PTR(-ENODEV);
 719
 720         mutex_lock(&devfreq_list_lock);
 721         list_for_each_entry(devfreq, &devfreq_list, node) {
 722                 if (devfreq->dev.parent
 723                         && devfreq->dev.parent->of_node == node) {
 724                         mutex_unlock(&devfreq_list_lock);
 725                         of_node_put(node);
 726                         return devfreq;
 727                 }
 728         }
 729         mutex_unlock(&devfreq_list_lock);
 730         of_node_put(node);
 731
 732         return ERR_PTR(-EPROBE_DEFER);
 733 }
 734 #else
 735 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 736 {
 737         return ERR_PTR(-ENODEV);
 738 }
 739 #endif /* CONFIG_OF */
 740 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 741
 742 /**
 743  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 744  * @dev:        the device to add devfreq feature.
 745  * @devfreq:    the devfreq instance to be removed
 746  */
 747 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 748 {
 749         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 750                                devm_devfreq_dev_match, devfreq));
 751 }
 752 EXPORT_SYMBOL(devm_devfreq_remove_device);
 753
 754 /**
 755  * devfreq_suspend_device() - Suspend devfreq of a device.
 756  * @devfreq: the devfreq instance to be suspended
 757  *
 758  * This function is intended to be called by the pm callbacks
 759  * (e.g., runtime_suspend, suspend) of the device driver that
 760  * holds the devfreq.
 761  */
 762 int devfreq_suspend_device(struct devfreq *devfreq)
 763 {
 764         if (!devfreq)
 765                 return -EINVAL;
 766
 767         if (!devfreq->governor)
 768                 return 0;
 769
 770         return devfreq->governor->event_handler(devfreq,
 771                                 DEVFREQ_GOV_SUSPEND, NULL);
 772 }
 773 EXPORT_SYMBOL(devfreq_suspend_device);
 774
 775 /**
 776  * devfreq_resume_device() - Resume devfreq of a device.
 777  * @devfreq: the devfreq instance to be resumed
 778  *
 779  * This function is intended to be called by the pm callbacks
 780  * (e.g., runtime_resume, resume) of the device driver that
 781  * holds the devfreq.
 782  */
 783 int devfreq_resume_device(struct devfreq *devfreq)
 784 {
 785         if (!devfreq)
 786                 return -EINVAL;
 787
 788         if (!devfreq->governor)
 789                 return 0;
 790
 791         return devfreq->governor->event_handler(devfreq,
 792                                 DEVFREQ_GOV_RESUME, NULL);
 793 }
 794 EXPORT_SYMBOL(devfreq_resume_device);
 795
 796 /**
 797  * devfreq_add_governor() - Add devfreq governor
 798  * @governor:   the devfreq governor to be added
 799  */
 800 int devfreq_add_governor(struct devfreq_governor *governor)
 801 {
 802         struct devfreq_governor *g;
 803         struct devfreq *devfreq;
 804         int err = 0;
 805
 806         if (!governor) {
 807                 pr_err("%s: Invalid parameters.\n", __func__);
 808                 return -EINVAL;
 809         }
 810
 811         mutex_lock(&devfreq_list_lock);
 812         g = find_devfreq_governor(governor->name);
 813         if (!IS_ERR(g)) {
 814                 pr_err("%s: governor %s already registered\n", __func__,
 815                        g->name);
 816                 err = -EINVAL;
 817                 goto err_out;
 818         }
 819
 820         list_add(&governor->node, &devfreq_governor_list);
 821
 822         list_for_each_entry(devfreq, &devfreq_list, node) {
 823                 int ret = 0;
 824                 struct device *dev = devfreq->dev.parent;
 825
 826                 if (!strncmp(devfreq->governor_name, governor->name,
 827                              DEVFREQ_NAME_LEN)) {
 828                         /* The following should never occur */
 829                         if (devfreq->governor) {
 830                                 dev_warn(dev,
 831                                          "%s: Governor %s already present\n",
 832                                          __func__, devfreq->governor->name);
 833                                 ret = devfreq->governor->event_handler(devfreq,
 834                                                         DEVFREQ_GOV_STOP, NULL);
 835                                 if (ret) {
 836                                         dev_warn(dev,
 837                                                  "%s: Governor %s stop = %d\n",
 838                                                  __func__,
 839                                                  devfreq->governor->name, ret);
 840                                 }
 841                                 /* Fall through */
 842                         }
 843                         devfreq->governor = governor;
 844                         ret = devfreq->governor->event_handler(devfreq,
 845                                                 DEVFREQ_GOV_START, NULL);
 846                         if (ret) {
 847                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 848                                          __func__, devfreq->governor->name,
 849                                          ret);
 850                         }
 851                 }
 852         }
 853
 854 err_out:
 855         mutex_unlock(&devfreq_list_lock);
 856
 857         return err;
 858 }
 859 EXPORT_SYMBOL(devfreq_add_governor);
 860
 861 /**
 862  * devfreq_remove_device() - Remove devfreq feature from a device.
 863  * @governor:   the devfreq governor to be removed
 864  */
 865 int devfreq_remove_governor(struct devfreq_governor *governor)
 866 {
 867         struct devfreq_governor *g;
 868         struct devfreq *devfreq;
 869         int err = 0;
 870
 871         if (!governor) {
 872                 pr_err("%s: Invalid parameters.\n", __func__);
 873                 return -EINVAL;
 874         }
 875
 876         mutex_lock(&devfreq_list_lock);
 877         g = find_devfreq_governor(governor->name);
 878         if (IS_ERR(g)) {
 879                 pr_err("%s: governor %s not registered\n", __func__,
 880                        governor->name);
 881                 err = PTR_ERR(g);
 882                 goto err_out;
 883         }
 884         list_for_each_entry(devfreq, &devfreq_list, node) {
 885                 int ret;
 886                 struct device *dev = devfreq->dev.parent;
 887
 888                 if (!strncmp(devfreq->governor_name, governor->name,
 889                              DEVFREQ_NAME_LEN)) {
 890                         /* we should have a devfreq governor! */
 891                         if (!devfreq->governor) {
 892                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 893                                          __func__, governor->name);
 894                                 continue;
 895                                 /* Fall through */
 896                         }
 897                         ret = devfreq->governor->event_handler(devfreq,
 898                                                 DEVFREQ_GOV_STOP, NULL);
 899                         if (ret) {
 900                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 901                                          __func__, devfreq->governor->name,
 902                                          ret);
 903                         }
 904                         devfreq->governor = NULL;
 905                 }
 906         }
 907
 908         list_del(&governor->node);
 909 err_out:
 910         mutex_unlock(&devfreq_list_lock);
 911
 912         return err;
 913 }
 914 EXPORT_SYMBOL(devfreq_remove_governor);
 915
 916 static ssize_t governor_show(struct device *dev,
 917                              struct device_attribute *attr, char *buf)
 918 {
 919         if (!to_devfreq(dev)->governor)
 920                 return -EINVAL;
 921
 922         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 923 }
 924
 925 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 926                               const char *buf, size_t count)
 927 {
 928         struct devfreq *df = to_devfreq(dev);
 929         int ret;
 930         char str_governor[DEVFREQ_NAME_LEN + 1];
 931         struct devfreq_governor *governor;
 932
 933         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 934         if (ret != 1)
 935                 return -EINVAL;
 936
 937         mutex_lock(&devfreq_list_lock);
 938         governor = find_devfreq_governor(str_governor);
 939         if (IS_ERR(governor)) {
 940                 ret = PTR_ERR(governor);
 941                 goto out;
 942         }
 943         if (df->governor == governor) {
 944                 ret = 0;
 945                 goto out;
 946         } else if ((df->governor && df->governor->immutable) ||
 947                                         governor->immutable) {
 948                 ret = -EINVAL;
 949                 goto out;
 950         }
 951
 952         if (df->governor) {
 953                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
 954                 if (ret) {
 955                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
 956                                  __func__, df->governor->name, ret);
 957                         goto out;
 958                 }
 959         }
 960         df->governor = governor;
 961         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
 962         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
 963         if (ret)
 964                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
 965                          __func__, df->governor->name, ret);
 966 out:
 967         mutex_unlock(&devfreq_list_lock);
 968
 969         if (!ret)
 970                 ret = count;
 971         return ret;
 972 }
 973 static DEVICE_ATTR_RW(governor);
 974
 975 static ssize_t available_governors_show(struct device *d,
 976                                         struct device_attribute *attr,
 977                                         char *buf)
 978 {
 979         struct devfreq *df = to_devfreq(d);
 980         ssize_t count = 0;
 981
 982         mutex_lock(&devfreq_list_lock);
 983
 984         /*
 985          * The devfreq with immutable governor (e.g., passive) shows
 986          * only own governor.
 987          */
 988         if (df->governor->immutable) {
 989                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
 990                                    "%s ", df->governor_name);
 991         /*
 992          * The devfreq device shows the registered governor except for
 993          * immutable governors such as passive governor .
 994          */
 995         } else {
 996                 struct devfreq_governor *governor;
 997
 998                 list_for_each_entry(governor, &devfreq_governor_list, node) {
 999                         if (governor->immutable)
1000                                 continue;
1001                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1002                                            "%s ", governor->name);
1003                 }
1004         }
1005
1006         mutex_unlock(&devfreq_list_lock);
1007
1008         /* Truncate the trailing space */
1009         if (count)
1010                 count--;
1011
1012         count += sprintf(&buf[count], "\n");
1013
1014         return count;
1015 }
1016 static DEVICE_ATTR_RO(available_governors);
1017
1018 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1019                              char *buf)
1020 {
1021         unsigned long freq;
1022         struct devfreq *devfreq = to_devfreq(dev);
1023
1024         if (devfreq->profile->get_cur_freq &&
1025                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1026                         return sprintf(buf, "%lu\n", freq);
1027
1028         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1029 }
1030 static DEVICE_ATTR_RO(cur_freq);
1031
1032 static ssize_t target_freq_show(struct device *dev,
1033                                 struct device_attribute *attr, char *buf)
1034 {
1035         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1036 }
1037 static DEVICE_ATTR_RO(target_freq);
1038
1039 static ssize_t polling_interval_show(struct device *dev,
1040                                      struct device_attribute *attr, char *buf)
1041 {
1042         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1043 }
1044
1045 static ssize_t polling_interval_store(struct device *dev,
1046                                       struct device_attribute *attr,
1047                                       const char *buf, size_t count)
1048 {
1049         struct devfreq *df = to_devfreq(dev);
1050         unsigned int value;
1051         int ret;
1052
1053         if (!df->governor)
1054                 return -EINVAL;
1055
1056         ret = sscanf(buf, "%u", &value);
1057         if (ret != 1)
1058                 return -EINVAL;
1059
1060         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1061         ret = count;
1062
1063         return ret;
1064 }
1065 static DEVICE_ATTR_RW(polling_interval);
1066
1067 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1068                               const char *buf, size_t count)
1069 {
1070         struct devfreq *df = to_devfreq(dev);
1071         unsigned long value;
1072         int ret;
1073         unsigned long max;
1074
1075         ret = sscanf(buf, "%lu", &value);
1076         if (ret != 1)
1077                 return -EINVAL;
1078
1079         mutex_lock(&df->lock);
1080         max = df->max_freq;
1081         if (value && max && value > max) {
1082                 ret = -EINVAL;
1083                 goto unlock;
1084         }
1085
1086         df->min_freq = value;
1087         update_devfreq(df);
1088         ret = count;
1089 unlock:
1090         mutex_unlock(&df->lock);
1091         return ret;
1092 }
1093
1094 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1095                               const char *buf, size_t count)
1096 {
1097         struct devfreq *df = to_devfreq(dev);
1098         unsigned long value;
1099         int ret;
1100         unsigned long min;
1101
1102         ret = sscanf(buf, "%lu", &value);
1103         if (ret != 1)
1104                 return -EINVAL;
1105
1106         mutex_lock(&df->lock);
1107         min = df->min_freq;
1108         if (value && min && value < min) {
1109                 ret = -EINVAL;
1110                 goto unlock;
1111         }
1112
1113         df->max_freq = value;
1114         update_devfreq(df);
1115         ret = count;
1116 unlock:
1117         mutex_unlock(&df->lock);
1118         return ret;
1119 }
1120
1121 #define show_one(name)                                          \
1122 static ssize_t name##_show                                      \
1123 (struct device *dev, struct device_attribute *attr, char *buf)  \
1124 {                                                               \
1125         return sprintf(buf, "%lu\n", to_devfreq(dev)->name);    \
1126 }
1127 show_one(min_freq);
1128 show_one(max_freq);
1129
1130 static DEVICE_ATTR_RW(min_freq);
1131 static DEVICE_ATTR_RW(max_freq);
1132
1133 static ssize_t available_frequencies_show(struct device *d,
1134                                           struct device_attribute *attr,
1135                                           char *buf)
1136 {
1137         struct devfreq *df = to_devfreq(d);
1138         struct device *dev = df->dev.parent;
1139         struct dev_pm_opp *opp;
1140         ssize_t count = 0;
1141         unsigned long freq = 0;
1142
1143         rcu_read_lock();
1144         do {
1145                 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1146                 if (IS_ERR(opp))
1147                         break;
1148
1149                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1150                                    "%lu ", freq);
1151                 freq++;
1152         } while (1);
1153         rcu_read_unlock();
1154
1155         /* Truncate the trailing space */
1156         if (count)
1157                 count--;
1158
1159         count += sprintf(&buf[count], "\n");
1160
1161         return count;
1162 }
1163 static DEVICE_ATTR_RO(available_frequencies);
1164
1165 static ssize_t trans_stat_show(struct device *dev,
1166                                struct device_attribute *attr, char *buf)
1167 {
1168         struct devfreq *devfreq = to_devfreq(dev);
1169         ssize_t len;
1170         int i, j;
1171         unsigned int max_state = devfreq->profile->max_state;
1172
1173         if (!devfreq->stop_polling &&
1174                         devfreq_update_status(devfreq, devfreq->previous_freq))
1175                 return 0;
1176         if (max_state == 0)
1177                 return sprintf(buf, "Not Supported.\n");
1178
1179         len = sprintf(buf, "     From  :   To\n");
1180         len += sprintf(buf + len, "           :");
1181         for (i = 0; i < max_state; i++)
1182                 len += sprintf(buf + len, "%10lu",
1183                                 devfreq->profile->freq_table[i]);
1184
1185         len += sprintf(buf + len, "   time(ms)\n");
1186
1187         for (i = 0; i < max_state; i++) {
1188                 if (devfreq->profile->freq_table[i]
1189                                         == devfreq->previous_freq) {
1190                         len += sprintf(buf + len, "*");
1191                 } else {
1192                         len += sprintf(buf + len, " ");
1193                 }
1194                 len += sprintf(buf + len, "%10lu:",
1195                                 devfreq->profile->freq_table[i]);
1196                 for (j = 0; j < max_state; j++)
1197                         len += sprintf(buf + len, "%10u",
1198                                 devfreq->trans_table[(i * max_state) + j]);
1199                 len += sprintf(buf + len, "%10u\n",
1200                         jiffies_to_msecs(devfreq->time_in_state[i]));
1201         }
1202
1203         len += sprintf(buf + len, "Total transition : %u\n",
1204                                         devfreq->total_trans);
1205         return len;
1206 }
1207 static DEVICE_ATTR_RO(trans_stat);
1208
1209 static struct attribute *devfreq_attrs[] = {
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 followings 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  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1256  * protected pointer. The reason for the same is that the opp pointer which is
1257  * returned will remain valid for use with opp_get_{voltage, freq} only while
1258  * under the locked area. The pointer returned must be used prior to unlocking
1259  * with rcu_read_unlock() to maintain the integrity of the pointer.
1260  */
1261 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1262                                            unsigned long *freq,
1263                                            u32 flags)
1264 {
1265         struct dev_pm_opp *opp;
1266
1267         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1268                 /* The freq is an upper bound. opp should be lower */
1269                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1270
1271                 /* If not available, use the closest opp */
1272                 if (opp == ERR_PTR(-ERANGE))
1273                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1274         } else {
1275                 /* The freq is an lower bound. opp should be higher */
1276                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1277
1278                 /* If not available, use the closest opp */
1279                 if (opp == ERR_PTR(-ERANGE))
1280                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1281         }
1282
1283         return opp;
1284 }
1285 EXPORT_SYMBOL(devfreq_recommended_opp);
1286
1287 /**
1288  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1289  *                                 for any changes in the OPP availability
1290  *                                 changes
1291  * @dev:        The devfreq user device. (parent of devfreq)
1292  * @devfreq:    The devfreq object.
1293  */
1294 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1295 {
1296         struct srcu_notifier_head *nh;
1297         int ret = 0;
1298
1299         rcu_read_lock();
1300         nh = dev_pm_opp_get_notifier(dev);
1301         if (IS_ERR(nh))
1302                 ret = PTR_ERR(nh);
1303         rcu_read_unlock();
1304         if (!ret)
1305                 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1306
1307         return ret;
1308 }
1309 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1310
1311 /**
1312  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1313  *                                   notified for any changes in the OPP
1314  *                                   availability changes anymore.
1315  * @dev:        The devfreq user device. (parent of devfreq)
1316  * @devfreq:    The devfreq object.
1317  *
1318  * At exit() callback of devfreq_dev_profile, this must be included if
1319  * devfreq_recommended_opp is used.
1320  */
1321 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1322 {
1323         struct srcu_notifier_head *nh;
1324         int ret = 0;
1325
1326         rcu_read_lock();
1327         nh = dev_pm_opp_get_notifier(dev);
1328         if (IS_ERR(nh))
1329                 ret = PTR_ERR(nh);
1330         rcu_read_unlock();
1331         if (!ret)
1332                 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1333
1334         return ret;
1335 }
1336 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1337
1338 static void devm_devfreq_opp_release(struct device *dev, void *res)
1339 {
1340         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1341 }
1342
1343 /**
1344  * devm_ devfreq_register_opp_notifier()
1345  *              - Resource-managed devfreq_register_opp_notifier()
1346  * @dev:        The devfreq user device. (parent of devfreq)
1347  * @devfreq:    The devfreq object.
1348  */
1349 int devm_devfreq_register_opp_notifier(struct device *dev,
1350                                        struct devfreq *devfreq)
1351 {
1352         struct devfreq **ptr;
1353         int ret;
1354
1355         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1356         if (!ptr)
1357                 return -ENOMEM;
1358
1359         ret = devfreq_register_opp_notifier(dev, devfreq);
1360         if (ret) {
1361                 devres_free(ptr);
1362                 return ret;
1363         }
1364
1365         *ptr = devfreq;
1366         devres_add(dev, ptr);
1367
1368         return 0;
1369 }
1370 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1371
1372 /**
1373  * devm_devfreq_unregister_opp_notifier()
1374  *              - Resource-managed devfreq_unregister_opp_notifier()
1375  * @dev:        The devfreq user device. (parent of devfreq)
1376  * @devfreq:    The devfreq object.
1377  */
1378 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1379                                          struct devfreq *devfreq)
1380 {
1381         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1382                                devm_devfreq_dev_match, devfreq));
1383 }
1384 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1385
1386 /**
1387  * devfreq_register_notifier() - Register a driver with devfreq
1388  * @devfreq:    The devfreq object.
1389  * @nb:         The notifier block to register.
1390  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1391  */
1392 int devfreq_register_notifier(struct devfreq *devfreq,
1393                                 struct notifier_block *nb,
1394                                 unsigned int list)
1395 {
1396         int ret = 0;
1397
1398         if (!devfreq)
1399                 return -EINVAL;
1400
1401         switch (list) {
1402         case DEVFREQ_TRANSITION_NOTIFIER:
1403                 ret = srcu_notifier_chain_register(
1404                                 &devfreq->transition_notifier_list, nb);
1405                 break;
1406         default:
1407                 ret = -EINVAL;
1408         }
1409
1410         return ret;
1411 }
1412 EXPORT_SYMBOL(devfreq_register_notifier);
1413
1414 /*
1415  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1416  * @devfreq:    The devfreq object.
1417  * @nb:         The notifier block to be unregistered.
1418  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1419  */
1420 int devfreq_unregister_notifier(struct devfreq *devfreq,
1421                                 struct notifier_block *nb,
1422                                 unsigned int list)
1423 {
1424         int ret = 0;
1425
1426         if (!devfreq)
1427                 return -EINVAL;
1428
1429         switch (list) {
1430         case DEVFREQ_TRANSITION_NOTIFIER:
1431                 ret = srcu_notifier_chain_unregister(
1432                                 &devfreq->transition_notifier_list, nb);
1433                 break;
1434         default:
1435                 ret = -EINVAL;
1436         }
1437
1438         return ret;
1439 }
1440 EXPORT_SYMBOL(devfreq_unregister_notifier);
1441
1442 struct devfreq_notifier_devres {
1443         struct devfreq *devfreq;
1444         struct notifier_block *nb;
1445         unsigned int list;
1446 };
1447
1448 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1449 {
1450         struct devfreq_notifier_devres *this = res;
1451
1452         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1453 }
1454
1455 /**
1456  * devm_devfreq_register_notifier()
1457         - Resource-managed devfreq_register_notifier()
1458  * @dev:        The devfreq user device. (parent of devfreq)
1459  * @devfreq:    The devfreq object.
1460  * @nb:         The notifier block to be unregistered.
1461  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1462  */
1463 int devm_devfreq_register_notifier(struct device *dev,
1464                                 struct devfreq *devfreq,
1465                                 struct notifier_block *nb,
1466                                 unsigned int list)
1467 {
1468         struct devfreq_notifier_devres *ptr;
1469         int ret;
1470
1471         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1472                                 GFP_KERNEL);
1473         if (!ptr)
1474                 return -ENOMEM;
1475
1476         ret = devfreq_register_notifier(devfreq, nb, list);
1477         if (ret) {
1478                 devres_free(ptr);
1479                 return ret;
1480         }
1481
1482         ptr->devfreq = devfreq;
1483         ptr->nb = nb;
1484         ptr->list = list;
1485         devres_add(dev, ptr);
1486
1487         return 0;
1488 }
1489 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1490
1491 /**
1492  * devm_devfreq_unregister_notifier()
1493         - Resource-managed devfreq_unregister_notifier()
1494  * @dev:        The devfreq user device. (parent of devfreq)
1495  * @devfreq:    The devfreq object.
1496  * @nb:         The notifier block to be unregistered.
1497  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1498  */
1499 void devm_devfreq_unregister_notifier(struct device *dev,
1500                                 struct devfreq *devfreq,
1501                                 struct notifier_block *nb,
1502                                 unsigned int list)
1503 {
1504         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1505                                devm_devfreq_dev_match, devfreq));
1506 }
1507 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);