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