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         lockdep_assert_held(&devfreq->lock);
 139         cur_time = jiffies;
 140
 141         /* Immediately exit if previous_freq is not initialized yet. */
 142         if (!devfreq->previous_freq)
 143                 goto out;
 144
 145         prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 146         if (prev_lev < 0) {
 147                 ret = prev_lev;
 148                 goto out;
 149         }
 150
 151         devfreq->time_in_state[prev_lev] +=
 152                          cur_time - devfreq->last_stat_updated;
 153
 154         lev = devfreq_get_freq_level(devfreq, freq);
 155         if (lev < 0) {
 156                 ret = lev;
 157                 goto out;
 158         }
 159
 160         if (lev != prev_lev) {
 161                 devfreq->trans_table[(prev_lev *
 162                                 devfreq->profile->max_state) + lev]++;
 163                 devfreq->total_trans++;
 164         }
 165
 166 out:
 167         devfreq->last_stat_updated = cur_time;
 168         return ret;
 169 }
 170 EXPORT_SYMBOL(devfreq_update_status);
 171
 172 /**
 173  * find_devfreq_governor() - find devfreq governor from name
 174  * @name:       name of the governor
 175  *
 176  * Search the list of devfreq governors and return the matched
 177  * governor's pointer. devfreq_list_lock should be held by the caller.
 178  */
 179 static struct devfreq_governor *find_devfreq_governor(const char *name)
 180 {
 181         struct devfreq_governor *tmp_governor;
 182
 183         if (IS_ERR_OR_NULL(name)) {
 184                 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 185                 return ERR_PTR(-EINVAL);
 186         }
 187         WARN(!mutex_is_locked(&devfreq_list_lock),
 188              "devfreq_list_lock must be locked.");
 189
 190         list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 191                 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 192                         return tmp_governor;
 193         }
 194
 195         return ERR_PTR(-ENODEV);
 196 }
 197
 198 static int devfreq_notify_transition(struct devfreq *devfreq,
 199                 struct devfreq_freqs *freqs, unsigned int state)
 200 {
 201         if (!devfreq)
 202                 return -EINVAL;
 203
 204         switch (state) {
 205         case DEVFREQ_PRECHANGE:
 206                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 207                                 DEVFREQ_PRECHANGE, freqs);
 208                 break;
 209
 210         case DEVFREQ_POSTCHANGE:
 211                 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 212                                 DEVFREQ_POSTCHANGE, freqs);
 213                 break;
 214         default:
 215                 return -EINVAL;
 216         }
 217
 218         return 0;
 219 }
 220
 221 /* Load monitoring helper functions for governors use */
 222
 223 /**
 224  * update_devfreq() - Reevaluate the device and configure frequency.
 225  * @devfreq:    the devfreq instance.
 226  *
 227  * Note: Lock devfreq->lock before calling update_devfreq
 228  *       This function is exported for governors.
 229  */
 230 int update_devfreq(struct devfreq *devfreq)
 231 {
 232         struct devfreq_freqs freqs;
 233         unsigned long freq, cur_freq;
 234         int err = 0;
 235         u32 flags = 0;
 236
 237         if (!mutex_is_locked(&devfreq->lock)) {
 238                 WARN(true, "devfreq->lock must be locked by the caller.\n");
 239                 return -EINVAL;
 240         }
 241
 242         if (!devfreq->governor)
 243                 return -EINVAL;
 244
 245         /* Reevaluate the proper frequency */
 246         err = devfreq->governor->get_target_freq(devfreq, &freq);
 247         if (err)
 248                 return err;
 249
 250         /*
 251          * Adjust the frequency with user freq and QoS.
 252          *
 253          * List from the highest priority
 254          * max_freq
 255          * min_freq
 256          */
 257
 258         if (devfreq->min_freq && freq < devfreq->min_freq) {
 259                 freq = devfreq->min_freq;
 260                 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 261         }
 262         if (devfreq->max_freq && freq > devfreq->max_freq) {
 263                 freq = devfreq->max_freq;
 264                 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 265         }
 266
 267         if (devfreq->profile->get_cur_freq)
 268                 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 269         else
 270                 cur_freq = devfreq->previous_freq;
 271
 272         freqs.old = cur_freq;
 273         freqs.new = freq;
 274         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 275
 276         err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 277         if (err) {
 278                 freqs.new = cur_freq;
 279                 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 280                 return err;
 281         }
 282
 283         freqs.new = freq;
 284         devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 285
 286         if (devfreq->profile->freq_table)
 287                 if (devfreq_update_status(devfreq, freq))
 288                         dev_err(&devfreq->dev,
 289                                 "Couldn't update frequency transition information.\n");
 290
 291         devfreq->previous_freq = freq;
 292         return err;
 293 }
 294 EXPORT_SYMBOL(update_devfreq);
 295
 296 /**
 297  * devfreq_monitor() - Periodically poll devfreq objects.
 298  * @work:       the work struct used to run devfreq_monitor periodically.
 299  *
 300  */
 301 static void devfreq_monitor(struct work_struct *work)
 302 {
 303         int err;
 304         struct devfreq *devfreq = container_of(work,
 305                                         struct devfreq, work.work);
 306
 307         mutex_lock(&devfreq->lock);
 308         err = update_devfreq(devfreq);
 309         if (err)
 310                 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 311
 312         queue_delayed_work(devfreq_wq, &devfreq->work,
 313                                 msecs_to_jiffies(devfreq->profile->polling_ms));
 314         mutex_unlock(&devfreq->lock);
 315 }
 316
 317 /**
 318  * devfreq_monitor_start() - Start load monitoring of devfreq instance
 319  * @devfreq:    the devfreq instance.
 320  *
 321  * Helper function for starting devfreq device load monitoing. By
 322  * default delayed work based monitoring is supported. Function
 323  * to be called from governor in response to DEVFREQ_GOV_START
 324  * event when device is added to devfreq framework.
 325  */
 326 void devfreq_monitor_start(struct devfreq *devfreq)
 327 {
 328         INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 329         if (devfreq->profile->polling_ms)
 330                 queue_delayed_work(devfreq_wq, &devfreq->work,
 331                         msecs_to_jiffies(devfreq->profile->polling_ms));
 332 }
 333 EXPORT_SYMBOL(devfreq_monitor_start);
 334
 335 /**
 336  * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 337  * @devfreq:    the devfreq instance.
 338  *
 339  * Helper function to stop devfreq device load monitoing. Function
 340  * to be called from governor in response to DEVFREQ_GOV_STOP
 341  * event when device is removed from devfreq framework.
 342  */
 343 void devfreq_monitor_stop(struct devfreq *devfreq)
 344 {
 345         cancel_delayed_work_sync(&devfreq->work);
 346 }
 347 EXPORT_SYMBOL(devfreq_monitor_stop);
 348
 349 /**
 350  * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 351  * @devfreq:    the devfreq instance.
 352  *
 353  * Helper function to suspend devfreq device load monitoing. Function
 354  * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 355  * event or when polling interval is set to zero.
 356  *
 357  * Note: Though this function is same as devfreq_monitor_stop(),
 358  * intentionally kept separate to provide hooks for collecting
 359  * transition statistics.
 360  */
 361 void devfreq_monitor_suspend(struct devfreq *devfreq)
 362 {
 363         mutex_lock(&devfreq->lock);
 364         if (devfreq->stop_polling) {
 365                 mutex_unlock(&devfreq->lock);
 366                 return;
 367         }
 368
 369         devfreq_update_status(devfreq, devfreq->previous_freq);
 370         devfreq->stop_polling = true;
 371         mutex_unlock(&devfreq->lock);
 372         cancel_delayed_work_sync(&devfreq->work);
 373 }
 374 EXPORT_SYMBOL(devfreq_monitor_suspend);
 375
 376 /**
 377  * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 378  * @devfreq:    the devfreq instance.
 379  *
 380  * Helper function to resume devfreq device load monitoing. Function
 381  * to be called from governor in response to DEVFREQ_GOV_RESUME
 382  * event or when polling interval is set to non-zero.
 383  */
 384 void devfreq_monitor_resume(struct devfreq *devfreq)
 385 {
 386         unsigned long freq;
 387
 388         mutex_lock(&devfreq->lock);
 389         if (!devfreq->stop_polling)
 390                 goto out;
 391
 392         if (!delayed_work_pending(&devfreq->work) &&
 393                         devfreq->profile->polling_ms)
 394                 queue_delayed_work(devfreq_wq, &devfreq->work,
 395                         msecs_to_jiffies(devfreq->profile->polling_ms));
 396
 397         devfreq->last_stat_updated = jiffies;
 398         devfreq->stop_polling = false;
 399
 400         if (devfreq->profile->get_cur_freq &&
 401                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 402                 devfreq->previous_freq = freq;
 403
 404 out:
 405         mutex_unlock(&devfreq->lock);
 406 }
 407 EXPORT_SYMBOL(devfreq_monitor_resume);
 408
 409 /**
 410  * devfreq_interval_update() - Update device devfreq monitoring interval
 411  * @devfreq:    the devfreq instance.
 412  * @delay:      new polling interval to be set.
 413  *
 414  * Helper function to set new load monitoring polling interval. Function
 415  * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
 416  */
 417 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 418 {
 419         unsigned int cur_delay = devfreq->profile->polling_ms;
 420         unsigned int new_delay = *delay;
 421
 422         mutex_lock(&devfreq->lock);
 423         devfreq->profile->polling_ms = new_delay;
 424
 425         if (devfreq->stop_polling)
 426                 goto out;
 427
 428         /* if new delay is zero, stop polling */
 429         if (!new_delay) {
 430                 mutex_unlock(&devfreq->lock);
 431                 cancel_delayed_work_sync(&devfreq->work);
 432                 return;
 433         }
 434
 435         /* if current delay is zero, start polling with new delay */
 436         if (!cur_delay) {
 437                 queue_delayed_work(devfreq_wq, &devfreq->work,
 438                         msecs_to_jiffies(devfreq->profile->polling_ms));
 439                 goto out;
 440         }
 441
 442         /* if current delay is greater than new delay, restart polling */
 443         if (cur_delay > new_delay) {
 444                 mutex_unlock(&devfreq->lock);
 445                 cancel_delayed_work_sync(&devfreq->work);
 446                 mutex_lock(&devfreq->lock);
 447                 if (!devfreq->stop_polling)
 448                         queue_delayed_work(devfreq_wq, &devfreq->work,
 449                               msecs_to_jiffies(devfreq->profile->polling_ms));
 450         }
 451 out:
 452         mutex_unlock(&devfreq->lock);
 453 }
 454 EXPORT_SYMBOL(devfreq_interval_update);
 455
 456 /**
 457  * devfreq_notifier_call() - Notify that the device frequency requirements
 458  *                         has been changed out of devfreq framework.
 459  * @nb:         the notifier_block (supposed to be devfreq->nb)
 460  * @type:       not used
 461  * @devp:       not used
 462  *
 463  * Called by a notifier that uses devfreq->nb.
 464  */
 465 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 466                                  void *devp)
 467 {
 468         struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 469         int ret;
 470
 471         mutex_lock(&devfreq->lock);
 472         ret = update_devfreq(devfreq);
 473         mutex_unlock(&devfreq->lock);
 474
 475         return ret;
 476 }
 477
 478 /**
 479  * _remove_devfreq() - Remove devfreq from the list and release its resources.
 480  * @devfreq:    the devfreq struct
 481  */
 482 static void _remove_devfreq(struct devfreq *devfreq)
 483 {
 484         mutex_lock(&devfreq_list_lock);
 485         list_del(&devfreq->node);
 486         mutex_unlock(&devfreq_list_lock);
 487
 488         if (devfreq->governor)
 489                 devfreq->governor->event_handler(devfreq,
 490                                                  DEVFREQ_GOV_STOP, NULL);
 491
 492         if (devfreq->profile->exit)
 493                 devfreq->profile->exit(devfreq->dev.parent);
 494
 495         mutex_destroy(&devfreq->lock);
 496         kfree(devfreq);
 497 }
 498
 499 /**
 500  * devfreq_dev_release() - Callback for struct device to release the device.
 501  * @dev:        the devfreq device
 502  *
 503  * This calls _remove_devfreq() if _remove_devfreq() is not called.
 504  */
 505 static void devfreq_dev_release(struct device *dev)
 506 {
 507         struct devfreq *devfreq = to_devfreq(dev);
 508
 509         _remove_devfreq(devfreq);
 510 }
 511
 512 /**
 513  * devfreq_add_device() - Add devfreq feature to the device
 514  * @dev:        the device to add devfreq feature.
 515  * @profile:    device-specific profile to run devfreq.
 516  * @governor_name:      name of the policy to choose frequency.
 517  * @data:       private data for the governor. The devfreq framework does not
 518  *              touch this value.
 519  */
 520 struct devfreq *devfreq_add_device(struct device *dev,
 521                                    struct devfreq_dev_profile *profile,
 522                                    const char *governor_name,
 523                                    void *data)
 524 {
 525         struct devfreq *devfreq;
 526         struct devfreq_governor *governor;
 527         int err = 0;
 528
 529         if (!dev || !profile || !governor_name) {
 530                 dev_err(dev, "%s: Invalid parameters.\n", __func__);
 531                 return ERR_PTR(-EINVAL);
 532         }
 533
 534         mutex_lock(&devfreq_list_lock);
 535         devfreq = find_device_devfreq(dev);
 536         mutex_unlock(&devfreq_list_lock);
 537         if (!IS_ERR(devfreq)) {
 538                 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
 539                 err = -EINVAL;
 540                 goto err_out;
 541         }
 542
 543         devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 544         if (!devfreq) {
 545                 dev_err(dev, "%s: Unable to create devfreq for the device\n",
 546                         __func__);
 547                 err = -ENOMEM;
 548                 goto err_out;
 549         }
 550
 551         mutex_init(&devfreq->lock);
 552         mutex_lock(&devfreq->lock);
 553         devfreq->dev.parent = dev;
 554         devfreq->dev.class = devfreq_class;
 555         devfreq->dev.release = devfreq_dev_release;
 556         INIT_LIST_HEAD(&devfreq->node);
 557         devfreq->profile = profile;
 558         strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 559         devfreq->previous_freq = profile->initial_freq;
 560         devfreq->last_status.current_frequency = profile->initial_freq;
 561         devfreq->data = data;
 562         devfreq->nb.notifier_call = devfreq_notifier_call;
 563
 564         if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
 565                 mutex_unlock(&devfreq->lock);
 566                 devfreq_set_freq_table(devfreq);
 567                 mutex_lock(&devfreq->lock);
 568         }
 569
 570         dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 571         err = device_register(&devfreq->dev);
 572         if (err) {
 573                 mutex_unlock(&devfreq->lock);
 574                 goto err_dev;
 575         }
 576
 577         devfreq->trans_table =  devm_kzalloc(&devfreq->dev, sizeof(unsigned int) *
 578                                                 devfreq->profile->max_state *
 579                                                 devfreq->profile->max_state,
 580                                                 GFP_KERNEL);
 581         devfreq->time_in_state = devm_kzalloc(&devfreq->dev, sizeof(unsigned long) *
 582                                                 devfreq->profile->max_state,
 583                                                 GFP_KERNEL);
 584         devfreq->last_stat_updated = jiffies;
 585
 586         srcu_init_notifier_head(&devfreq->transition_notifier_list);
 587
 588         mutex_unlock(&devfreq->lock);
 589
 590         mutex_lock(&devfreq_list_lock);
 591         list_add(&devfreq->node, &devfreq_list);
 592
 593         governor = find_devfreq_governor(devfreq->governor_name);
 594         if (IS_ERR(governor)) {
 595                 dev_err(dev, "%s: Unable to find governor for the device\n",
 596                         __func__);
 597                 err = PTR_ERR(governor);
 598                 goto err_init;
 599         }
 600
 601         devfreq->governor = governor;
 602         err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 603                                                 NULL);
 604         if (err) {
 605                 dev_err(dev, "%s: Unable to start governor for the device\n",
 606                         __func__);
 607                 goto err_init;
 608         }
 609         mutex_unlock(&devfreq_list_lock);
 610
 611         return devfreq;
 612
 613 err_init:
 614         list_del(&devfreq->node);
 615         mutex_unlock(&devfreq_list_lock);
 616
 617         device_unregister(&devfreq->dev);
 618 err_dev:
 619         if (devfreq)
 620                 kfree(devfreq);
 621 err_out:
 622         return ERR_PTR(err);
 623 }
 624 EXPORT_SYMBOL(devfreq_add_device);
 625
 626 /**
 627  * devfreq_remove_device() - Remove devfreq feature from a device.
 628  * @devfreq:    the devfreq instance to be removed
 629  *
 630  * The opposite of devfreq_add_device().
 631  */
 632 int devfreq_remove_device(struct devfreq *devfreq)
 633 {
 634         if (!devfreq)
 635                 return -EINVAL;
 636
 637         device_unregister(&devfreq->dev);
 638
 639         return 0;
 640 }
 641 EXPORT_SYMBOL(devfreq_remove_device);
 642
 643 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 644 {
 645         struct devfreq **r = res;
 646
 647         if (WARN_ON(!r || !*r))
 648                 return 0;
 649
 650         return *r == data;
 651 }
 652
 653 static void devm_devfreq_dev_release(struct device *dev, void *res)
 654 {
 655         devfreq_remove_device(*(struct devfreq **)res);
 656 }
 657
 658 /**
 659  * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 660  * @dev:        the device to add devfreq feature.
 661  * @profile:    device-specific profile to run devfreq.
 662  * @governor_name:      name of the policy to choose frequency.
 663  * @data:       private data for the governor. The devfreq framework does not
 664  *              touch this value.
 665  *
 666  * This function manages automatically the memory of devfreq device using device
 667  * resource management and simplify the free operation for memory of devfreq
 668  * device.
 669  */
 670 struct devfreq *devm_devfreq_add_device(struct device *dev,
 671                                         struct devfreq_dev_profile *profile,
 672                                         const char *governor_name,
 673                                         void *data)
 674 {
 675         struct devfreq **ptr, *devfreq;
 676
 677         ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
 678         if (!ptr)
 679                 return ERR_PTR(-ENOMEM);
 680
 681         devfreq = devfreq_add_device(dev, profile, governor_name, data);
 682         if (IS_ERR(devfreq)) {
 683                 devres_free(ptr);
 684                 return devfreq;
 685         }
 686
 687         *ptr = devfreq;
 688         devres_add(dev, ptr);
 689
 690         return devfreq;
 691 }
 692 EXPORT_SYMBOL(devm_devfreq_add_device);
 693
 694 #ifdef CONFIG_OF
 695 /*
 696  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 697  * @dev - instance to the given device
 698  * @index - index into list of devfreq
 699  *
 700  * return the instance of devfreq device
 701  */
 702 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 703 {
 704         struct device_node *node;
 705         struct devfreq *devfreq;
 706
 707         if (!dev)
 708                 return ERR_PTR(-EINVAL);
 709
 710         if (!dev->of_node)
 711                 return ERR_PTR(-EINVAL);
 712
 713         node = of_parse_phandle(dev->of_node, "devfreq", index);
 714         if (!node)
 715                 return ERR_PTR(-ENODEV);
 716
 717         mutex_lock(&devfreq_list_lock);
 718         list_for_each_entry(devfreq, &devfreq_list, node) {
 719                 if (devfreq->dev.parent
 720                         && devfreq->dev.parent->of_node == node) {
 721                         mutex_unlock(&devfreq_list_lock);
 722                         of_node_put(node);
 723                         return devfreq;
 724                 }
 725         }
 726         mutex_unlock(&devfreq_list_lock);
 727         of_node_put(node);
 728
 729         return ERR_PTR(-EPROBE_DEFER);
 730 }
 731 #else
 732 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 733 {
 734         return ERR_PTR(-ENODEV);
 735 }
 736 #endif /* CONFIG_OF */
 737 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 738
 739 /**
 740  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 741  * @dev:        the device to add devfreq feature.
 742  * @devfreq:    the devfreq instance to be removed
 743  */
 744 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
 745 {
 746         WARN_ON(devres_release(dev, devm_devfreq_dev_release,
 747                                devm_devfreq_dev_match, devfreq));
 748 }
 749 EXPORT_SYMBOL(devm_devfreq_remove_device);
 750
 751 /**
 752  * devfreq_suspend_device() - Suspend devfreq of a device.
 753  * @devfreq: the devfreq instance to be suspended
 754  *
 755  * This function is intended to be called by the pm callbacks
 756  * (e.g., runtime_suspend, suspend) of the device driver that
 757  * holds the devfreq.
 758  */
 759 int devfreq_suspend_device(struct devfreq *devfreq)
 760 {
 761         if (!devfreq)
 762                 return -EINVAL;
 763
 764         if (!devfreq->governor)
 765                 return 0;
 766
 767         return devfreq->governor->event_handler(devfreq,
 768                                 DEVFREQ_GOV_SUSPEND, NULL);
 769 }
 770 EXPORT_SYMBOL(devfreq_suspend_device);
 771
 772 /**
 773  * devfreq_resume_device() - Resume devfreq of a device.
 774  * @devfreq: the devfreq instance to be resumed
 775  *
 776  * This function is intended to be called by the pm callbacks
 777  * (e.g., runtime_resume, resume) of the device driver that
 778  * holds the devfreq.
 779  */
 780 int devfreq_resume_device(struct devfreq *devfreq)
 781 {
 782         if (!devfreq)
 783                 return -EINVAL;
 784
 785         if (!devfreq->governor)
 786                 return 0;
 787
 788         return devfreq->governor->event_handler(devfreq,
 789                                 DEVFREQ_GOV_RESUME, NULL);
 790 }
 791 EXPORT_SYMBOL(devfreq_resume_device);
 792
 793 /**
 794  * devfreq_add_governor() - Add devfreq governor
 795  * @governor:   the devfreq governor to be added
 796  */
 797 int devfreq_add_governor(struct devfreq_governor *governor)
 798 {
 799         struct devfreq_governor *g;
 800         struct devfreq *devfreq;
 801         int err = 0;
 802
 803         if (!governor) {
 804                 pr_err("%s: Invalid parameters.\n", __func__);
 805                 return -EINVAL;
 806         }
 807
 808         mutex_lock(&devfreq_list_lock);
 809         g = find_devfreq_governor(governor->name);
 810         if (!IS_ERR(g)) {
 811                 pr_err("%s: governor %s already registered\n", __func__,
 812                        g->name);
 813                 err = -EINVAL;
 814                 goto err_out;
 815         }
 816
 817         list_add(&governor->node, &devfreq_governor_list);
 818
 819         list_for_each_entry(devfreq, &devfreq_list, node) {
 820                 int ret = 0;
 821                 struct device *dev = devfreq->dev.parent;
 822
 823                 if (!strncmp(devfreq->governor_name, governor->name,
 824                              DEVFREQ_NAME_LEN)) {
 825                         /* The following should never occur */
 826                         if (devfreq->governor) {
 827                                 dev_warn(dev,
 828                                          "%s: Governor %s already present\n",
 829                                          __func__, devfreq->governor->name);
 830                                 ret = devfreq->governor->event_handler(devfreq,
 831                                                         DEVFREQ_GOV_STOP, NULL);
 832                                 if (ret) {
 833                                         dev_warn(dev,
 834                                                  "%s: Governor %s stop = %d\n",
 835                                                  __func__,
 836                                                  devfreq->governor->name, ret);
 837                                 }
 838                                 /* Fall through */
 839                         }
 840                         devfreq->governor = governor;
 841                         ret = devfreq->governor->event_handler(devfreq,
 842                                                 DEVFREQ_GOV_START, NULL);
 843                         if (ret) {
 844                                 dev_warn(dev, "%s: Governor %s start=%d\n",
 845                                          __func__, devfreq->governor->name,
 846                                          ret);
 847                         }
 848                 }
 849         }
 850
 851 err_out:
 852         mutex_unlock(&devfreq_list_lock);
 853
 854         return err;
 855 }
 856 EXPORT_SYMBOL(devfreq_add_governor);
 857
 858 /**
 859  * devfreq_remove_device() - Remove devfreq feature from a device.
 860  * @governor:   the devfreq governor to be removed
 861  */
 862 int devfreq_remove_governor(struct devfreq_governor *governor)
 863 {
 864         struct devfreq_governor *g;
 865         struct devfreq *devfreq;
 866         int err = 0;
 867
 868         if (!governor) {
 869                 pr_err("%s: Invalid parameters.\n", __func__);
 870                 return -EINVAL;
 871         }
 872
 873         mutex_lock(&devfreq_list_lock);
 874         g = find_devfreq_governor(governor->name);
 875         if (IS_ERR(g)) {
 876                 pr_err("%s: governor %s not registered\n", __func__,
 877                        governor->name);
 878                 err = PTR_ERR(g);
 879                 goto err_out;
 880         }
 881         list_for_each_entry(devfreq, &devfreq_list, node) {
 882                 int ret;
 883                 struct device *dev = devfreq->dev.parent;
 884
 885                 if (!strncmp(devfreq->governor_name, governor->name,
 886                              DEVFREQ_NAME_LEN)) {
 887                         /* we should have a devfreq governor! */
 888                         if (!devfreq->governor) {
 889                                 dev_warn(dev, "%s: Governor %s NOT present\n",
 890                                          __func__, governor->name);
 891                                 continue;
 892                                 /* Fall through */
 893                         }
 894                         ret = devfreq->governor->event_handler(devfreq,
 895                                                 DEVFREQ_GOV_STOP, NULL);
 896                         if (ret) {
 897                                 dev_warn(dev, "%s: Governor %s stop=%d\n",
 898                                          __func__, devfreq->governor->name,
 899                                          ret);
 900                         }
 901                         devfreq->governor = NULL;
 902                 }
 903         }
 904
 905         list_del(&governor->node);
 906 err_out:
 907         mutex_unlock(&devfreq_list_lock);
 908
 909         return err;
 910 }
 911 EXPORT_SYMBOL(devfreq_remove_governor);
 912
 913 static ssize_t governor_show(struct device *dev,
 914                              struct device_attribute *attr, char *buf)
 915 {
 916         if (!to_devfreq(dev)->governor)
 917                 return -EINVAL;
 918
 919         return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
 920 }
 921
 922 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 923                               const char *buf, size_t count)
 924 {
 925         struct devfreq *df = to_devfreq(dev);
 926         int ret;
 927         char str_governor[DEVFREQ_NAME_LEN + 1];
 928         struct devfreq_governor *governor;
 929
 930         ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
 931         if (ret != 1)
 932                 return -EINVAL;
 933
 934         mutex_lock(&devfreq_list_lock);
 935         governor = find_devfreq_governor(str_governor);
 936         if (IS_ERR(governor)) {
 937                 ret = PTR_ERR(governor);
 938                 goto out;
 939         }
 940         if (df->governor == governor) {
 941                 ret = 0;
 942                 goto out;
 943         } else if ((df->governor && df->governor->immutable) ||
 944                                         governor->immutable) {
 945                 ret = -EINVAL;
 946                 goto out;
 947         }
 948
 949         if (df->governor) {
 950                 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
 951                 if (ret) {
 952                         dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
 953                                  __func__, df->governor->name, ret);
 954                         goto out;
 955                 }
 956         }
 957         df->governor = governor;
 958         strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
 959         ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
 960         if (ret)
 961                 dev_warn(dev, "%s: Governor %s not started(%d)\n",
 962                          __func__, df->governor->name, ret);
 963 out:
 964         mutex_unlock(&devfreq_list_lock);
 965
 966         if (!ret)
 967                 ret = count;
 968         return ret;
 969 }
 970 static DEVICE_ATTR_RW(governor);
 971
 972 static ssize_t available_governors_show(struct device *d,
 973                                         struct device_attribute *attr,
 974                                         char *buf)
 975 {
 976         struct devfreq *df = to_devfreq(d);
 977         ssize_t count = 0;
 978
 979         mutex_lock(&devfreq_list_lock);
 980
 981         /*
 982          * The devfreq with immutable governor (e.g., passive) shows
 983          * only own governor.
 984          */
 985         if (df->governor && df->governor->immutable) {
 986                 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
 987                                    "%s ", df->governor_name);
 988         /*
 989          * The devfreq device shows the registered governor except for
 990          * immutable governors such as passive governor .
 991          */
 992         } else {
 993                 struct devfreq_governor *governor;
 994
 995                 list_for_each_entry(governor, &devfreq_governor_list, node) {
 996                         if (governor->immutable)
 997                                 continue;
 998                         count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
 999                                            "%s ", governor->name);
1000                 }
1001         }
1002
1003         mutex_unlock(&devfreq_list_lock);
1004
1005         /* Truncate the trailing space */
1006         if (count)
1007                 count--;
1008
1009         count += sprintf(&buf[count], "\n");
1010
1011         return count;
1012 }
1013 static DEVICE_ATTR_RO(available_governors);
1014
1015 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1016                              char *buf)
1017 {
1018         unsigned long freq;
1019         struct devfreq *devfreq = to_devfreq(dev);
1020
1021         if (devfreq->profile->get_cur_freq &&
1022                 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1023                         return sprintf(buf, "%lu\n", freq);
1024
1025         return sprintf(buf, "%lu\n", devfreq->previous_freq);
1026 }
1027 static DEVICE_ATTR_RO(cur_freq);
1028
1029 static ssize_t target_freq_show(struct device *dev,
1030                                 struct device_attribute *attr, char *buf)
1031 {
1032         return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1033 }
1034 static DEVICE_ATTR_RO(target_freq);
1035
1036 static ssize_t polling_interval_show(struct device *dev,
1037                                      struct device_attribute *attr, char *buf)
1038 {
1039         return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1040 }
1041
1042 static ssize_t polling_interval_store(struct device *dev,
1043                                       struct device_attribute *attr,
1044                                       const char *buf, size_t count)
1045 {
1046         struct devfreq *df = to_devfreq(dev);
1047         unsigned int value;
1048         int ret;
1049
1050         if (!df->governor)
1051                 return -EINVAL;
1052
1053         ret = sscanf(buf, "%u", &value);
1054         if (ret != 1)
1055                 return -EINVAL;
1056
1057         df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1058         ret = count;
1059
1060         return ret;
1061 }
1062 static DEVICE_ATTR_RW(polling_interval);
1063
1064 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1065                               const char *buf, size_t count)
1066 {
1067         struct devfreq *df = to_devfreq(dev);
1068         unsigned long value;
1069         int ret;
1070         unsigned long max;
1071
1072         ret = sscanf(buf, "%lu", &value);
1073         if (ret != 1)
1074                 return -EINVAL;
1075
1076         mutex_lock(&df->lock);
1077         max = df->max_freq;
1078         if (value && max && value > max) {
1079                 ret = -EINVAL;
1080                 goto unlock;
1081         }
1082
1083         df->min_freq = value;
1084         update_devfreq(df);
1085         ret = count;
1086 unlock:
1087         mutex_unlock(&df->lock);
1088         return ret;
1089 }
1090
1091 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1092                               const char *buf, size_t count)
1093 {
1094         struct devfreq *df = to_devfreq(dev);
1095         unsigned long value;
1096         int ret;
1097         unsigned long min;
1098
1099         ret = sscanf(buf, "%lu", &value);
1100         if (ret != 1)
1101                 return -EINVAL;
1102
1103         mutex_lock(&df->lock);
1104         min = df->min_freq;
1105         if (value && min && value < min) {
1106                 ret = -EINVAL;
1107                 goto unlock;
1108         }
1109
1110         df->max_freq = value;
1111         update_devfreq(df);
1112         ret = count;
1113 unlock:
1114         mutex_unlock(&df->lock);
1115         return ret;
1116 }
1117
1118 #define show_one(name)                                          \
1119 static ssize_t name##_show                                      \
1120 (struct device *dev, struct device_attribute *attr, char *buf)  \
1121 {                                                               \
1122         return sprintf(buf, "%lu\n", to_devfreq(dev)->name);    \
1123 }
1124 show_one(min_freq);
1125 show_one(max_freq);
1126
1127 static DEVICE_ATTR_RW(min_freq);
1128 static DEVICE_ATTR_RW(max_freq);
1129
1130 static ssize_t available_frequencies_show(struct device *d,
1131                                           struct device_attribute *attr,
1132                                           char *buf)
1133 {
1134         struct devfreq *df = to_devfreq(d);
1135         struct device *dev = df->dev.parent;
1136         struct dev_pm_opp *opp;
1137         ssize_t count = 0;
1138         unsigned long freq = 0;
1139
1140         rcu_read_lock();
1141         do {
1142                 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1143                 if (IS_ERR(opp))
1144                         break;
1145
1146                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1147                                    "%lu ", freq);
1148                 freq++;
1149         } while (1);
1150         rcu_read_unlock();
1151
1152         /* Truncate the trailing space */
1153         if (count)
1154                 count--;
1155
1156         count += sprintf(&buf[count], "\n");
1157
1158         return count;
1159 }
1160 static DEVICE_ATTR_RO(available_frequencies);
1161
1162 static ssize_t trans_stat_show(struct device *dev,
1163                                struct device_attribute *attr, char *buf)
1164 {
1165         struct devfreq *devfreq = to_devfreq(dev);
1166         ssize_t len;
1167         int i, j;
1168         unsigned int max_state = devfreq->profile->max_state;
1169
1170         if (max_state == 0)
1171                 return sprintf(buf, "Not Supported.\n");
1172
1173         mutex_lock(&devfreq->lock);
1174         if (!devfreq->stop_polling &&
1175                         devfreq_update_status(devfreq, devfreq->previous_freq)) {
1176                 mutex_unlock(&devfreq->lock);
1177                 return 0;
1178         }
1179         mutex_unlock(&devfreq->lock);
1180
1181         len = sprintf(buf, "     From  :   To\n");
1182         len += sprintf(buf + len, "           :");
1183         for (i = 0; i < max_state; i++)
1184                 len += sprintf(buf + len, "%10lu",
1185                                 devfreq->profile->freq_table[i]);
1186
1187         len += sprintf(buf + len, "   time(ms)\n");
1188
1189         for (i = 0; i < max_state; i++) {
1190                 if (devfreq->profile->freq_table[i]
1191                                         == devfreq->previous_freq) {
1192                         len += sprintf(buf + len, "*");
1193                 } else {
1194                         len += sprintf(buf + len, " ");
1195                 }
1196                 len += sprintf(buf + len, "%10lu:",
1197                                 devfreq->profile->freq_table[i]);
1198                 for (j = 0; j < max_state; j++)
1199                         len += sprintf(buf + len, "%10u",
1200                                 devfreq->trans_table[(i * max_state) + j]);
1201                 len += sprintf(buf + len, "%10u\n",
1202                         jiffies_to_msecs(devfreq->time_in_state[i]));
1203         }
1204
1205         len += sprintf(buf + len, "Total transition : %u\n",
1206                                         devfreq->total_trans);
1207         return len;
1208 }
1209 static DEVICE_ATTR_RO(trans_stat);
1210
1211 static struct attribute *devfreq_attrs[] = {
1212         &dev_attr_governor.attr,
1213         &dev_attr_available_governors.attr,
1214         &dev_attr_cur_freq.attr,
1215         &dev_attr_available_frequencies.attr,
1216         &dev_attr_target_freq.attr,
1217         &dev_attr_polling_interval.attr,
1218         &dev_attr_min_freq.attr,
1219         &dev_attr_max_freq.attr,
1220         &dev_attr_trans_stat.attr,
1221         NULL,
1222 };
1223 ATTRIBUTE_GROUPS(devfreq);
1224
1225 static int __init devfreq_init(void)
1226 {
1227         devfreq_class = class_create(THIS_MODULE, "devfreq");
1228         if (IS_ERR(devfreq_class)) {
1229                 pr_err("%s: couldn't create class\n", __FILE__);
1230                 return PTR_ERR(devfreq_class);
1231         }
1232
1233         devfreq_wq = create_freezable_workqueue("devfreq_wq");
1234         if (!devfreq_wq) {
1235                 class_destroy(devfreq_class);
1236                 pr_err("%s: couldn't create workqueue\n", __FILE__);
1237                 return -ENOMEM;
1238         }
1239         devfreq_class->dev_groups = devfreq_groups;
1240
1241         return 0;
1242 }
1243 subsys_initcall(devfreq_init);
1244
1245 /*
1246  * The followings are helper functions for devfreq user device drivers with
1247  * OPP framework.
1248  */
1249
1250 /**
1251  * devfreq_recommended_opp() - Helper function to get proper OPP for the
1252  *                           freq value given to target callback.
1253  * @dev:        The devfreq user device. (parent of devfreq)
1254  * @freq:       The frequency given to target function
1255  * @flags:      Flags handed from devfreq framework.
1256  *
1257  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1258  * protected pointer. The reason for the same is that the opp pointer which is
1259  * returned will remain valid for use with opp_get_{voltage, freq} only while
1260  * under the locked area. The pointer returned must be used prior to unlocking
1261  * with rcu_read_unlock() to maintain the integrity of the pointer.
1262  */
1263 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1264                                            unsigned long *freq,
1265                                            u32 flags)
1266 {
1267         struct dev_pm_opp *opp;
1268
1269         if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1270                 /* The freq is an upper bound. opp should be lower */
1271                 opp = dev_pm_opp_find_freq_floor(dev, freq);
1272
1273                 /* If not available, use the closest opp */
1274                 if (opp == ERR_PTR(-ERANGE))
1275                         opp = dev_pm_opp_find_freq_ceil(dev, freq);
1276         } else {
1277                 /* The freq is an lower bound. opp should be higher */
1278                 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1279
1280                 /* If not available, use the closest opp */
1281                 if (opp == ERR_PTR(-ERANGE))
1282                         opp = dev_pm_opp_find_freq_floor(dev, freq);
1283         }
1284
1285         return opp;
1286 }
1287 EXPORT_SYMBOL(devfreq_recommended_opp);
1288
1289 /**
1290  * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1291  *                                 for any changes in the OPP availability
1292  *                                 changes
1293  * @dev:        The devfreq user device. (parent of devfreq)
1294  * @devfreq:    The devfreq object.
1295  */
1296 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1297 {
1298         struct srcu_notifier_head *nh;
1299         int ret = 0;
1300
1301         rcu_read_lock();
1302         nh = dev_pm_opp_get_notifier(dev);
1303         if (IS_ERR(nh))
1304                 ret = PTR_ERR(nh);
1305         rcu_read_unlock();
1306         if (!ret)
1307                 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1308
1309         return ret;
1310 }
1311 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1312
1313 /**
1314  * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1315  *                                   notified for any changes in the OPP
1316  *                                   availability changes anymore.
1317  * @dev:        The devfreq user device. (parent of devfreq)
1318  * @devfreq:    The devfreq object.
1319  *
1320  * At exit() callback of devfreq_dev_profile, this must be included if
1321  * devfreq_recommended_opp is used.
1322  */
1323 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1324 {
1325         struct srcu_notifier_head *nh;
1326         int ret = 0;
1327
1328         rcu_read_lock();
1329         nh = dev_pm_opp_get_notifier(dev);
1330         if (IS_ERR(nh))
1331                 ret = PTR_ERR(nh);
1332         rcu_read_unlock();
1333         if (!ret)
1334                 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1335
1336         return ret;
1337 }
1338 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1339
1340 static void devm_devfreq_opp_release(struct device *dev, void *res)
1341 {
1342         devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1343 }
1344
1345 /**
1346  * devm_ devfreq_register_opp_notifier()
1347  *              - Resource-managed devfreq_register_opp_notifier()
1348  * @dev:        The devfreq user device. (parent of devfreq)
1349  * @devfreq:    The devfreq object.
1350  */
1351 int devm_devfreq_register_opp_notifier(struct device *dev,
1352                                        struct devfreq *devfreq)
1353 {
1354         struct devfreq **ptr;
1355         int ret;
1356
1357         ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1358         if (!ptr)
1359                 return -ENOMEM;
1360
1361         ret = devfreq_register_opp_notifier(dev, devfreq);
1362         if (ret) {
1363                 devres_free(ptr);
1364                 return ret;
1365         }
1366
1367         *ptr = devfreq;
1368         devres_add(dev, ptr);
1369
1370         return 0;
1371 }
1372 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1373
1374 /**
1375  * devm_devfreq_unregister_opp_notifier()
1376  *              - Resource-managed devfreq_unregister_opp_notifier()
1377  * @dev:        The devfreq user device. (parent of devfreq)
1378  * @devfreq:    The devfreq object.
1379  */
1380 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1381                                          struct devfreq *devfreq)
1382 {
1383         WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1384                                devm_devfreq_dev_match, devfreq));
1385 }
1386 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1387
1388 /**
1389  * devfreq_register_notifier() - Register a driver with devfreq
1390  * @devfreq:    The devfreq object.
1391  * @nb:         The notifier block to register.
1392  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1393  */
1394 int devfreq_register_notifier(struct devfreq *devfreq,
1395                                 struct notifier_block *nb,
1396                                 unsigned int list)
1397 {
1398         int ret = 0;
1399
1400         if (!devfreq)
1401                 return -EINVAL;
1402
1403         switch (list) {
1404         case DEVFREQ_TRANSITION_NOTIFIER:
1405                 ret = srcu_notifier_chain_register(
1406                                 &devfreq->transition_notifier_list, nb);
1407                 break;
1408         default:
1409                 ret = -EINVAL;
1410         }
1411
1412         return ret;
1413 }
1414 EXPORT_SYMBOL(devfreq_register_notifier);
1415
1416 /*
1417  * devfreq_unregister_notifier() - Unregister a driver with devfreq
1418  * @devfreq:    The devfreq object.
1419  * @nb:         The notifier block to be unregistered.
1420  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1421  */
1422 int devfreq_unregister_notifier(struct devfreq *devfreq,
1423                                 struct notifier_block *nb,
1424                                 unsigned int list)
1425 {
1426         int ret = 0;
1427
1428         if (!devfreq)
1429                 return -EINVAL;
1430
1431         switch (list) {
1432         case DEVFREQ_TRANSITION_NOTIFIER:
1433                 ret = srcu_notifier_chain_unregister(
1434                                 &devfreq->transition_notifier_list, nb);
1435                 break;
1436         default:
1437                 ret = -EINVAL;
1438         }
1439
1440         return ret;
1441 }
1442 EXPORT_SYMBOL(devfreq_unregister_notifier);
1443
1444 struct devfreq_notifier_devres {
1445         struct devfreq *devfreq;
1446         struct notifier_block *nb;
1447         unsigned int list;
1448 };
1449
1450 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1451 {
1452         struct devfreq_notifier_devres *this = res;
1453
1454         devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1455 }
1456
1457 /**
1458  * devm_devfreq_register_notifier()
1459         - Resource-managed devfreq_register_notifier()
1460  * @dev:        The devfreq user device. (parent of devfreq)
1461  * @devfreq:    The devfreq object.
1462  * @nb:         The notifier block to be unregistered.
1463  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1464  */
1465 int devm_devfreq_register_notifier(struct device *dev,
1466                                 struct devfreq *devfreq,
1467                                 struct notifier_block *nb,
1468                                 unsigned int list)
1469 {
1470         struct devfreq_notifier_devres *ptr;
1471         int ret;
1472
1473         ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1474                                 GFP_KERNEL);
1475         if (!ptr)
1476                 return -ENOMEM;
1477
1478         ret = devfreq_register_notifier(devfreq, nb, list);
1479         if (ret) {
1480                 devres_free(ptr);
1481                 return ret;
1482         }
1483
1484         ptr->devfreq = devfreq;
1485         ptr->nb = nb;
1486         ptr->list = list;
1487         devres_add(dev, ptr);
1488
1489         return 0;
1490 }
1491 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1492
1493 /**
1494  * devm_devfreq_unregister_notifier()
1495         - Resource-managed devfreq_unregister_notifier()
1496  * @dev:        The devfreq user device. (parent of devfreq)
1497  * @devfreq:    The devfreq object.
1498  * @nb:         The notifier block to be unregistered.
1499  * @list:       DEVFREQ_TRANSITION_NOTIFIER.
1500  */
1501 void devm_devfreq_unregister_notifier(struct device *dev,
1502                                 struct devfreq *devfreq,
1503                                 struct notifier_block *nb,
1504                                 unsigned int list)
1505 {
1506         WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1507                                devm_devfreq_dev_match, devfreq));
1508 }
1509 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);