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1/*
2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
3 * for Non-CPU Devices.
4 *
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/errno.h>
16#include <linux/err.h>
17#include <linux/init.h>
18#include <linux/export.h>
19#include <linux/slab.h>
20#include <linux/stat.h>
21#include <linux/pm_opp.h>
22#include <linux/devfreq.h>
23#include <linux/workqueue.h>
24#include <linux/platform_device.h>
25#include <linux/list.h>
26#include <linux/printk.h>
27#include <linux/hrtimer.h>
28#include <linux/of.h>
29#include "governor.h"
30
31#define MAX(a,b) ((a > b) ? a : b)
32#define MIN(a,b) ((a < b) ? a : b)
33
34static struct class *devfreq_class;
35
36/*
37 * devfreq core provides delayed work based load monitoring helper
38 * functions. Governors can use these or can implement their own
39 * monitoring mechanism.
40 */
41static struct workqueue_struct *devfreq_wq;
42
43/* The list of all device-devfreq governors */
44static LIST_HEAD(devfreq_governor_list);
45/* The list of all device-devfreq */
46static LIST_HEAD(devfreq_list);
47static DEFINE_MUTEX(devfreq_list_lock);
48
49/**
50 * find_device_devfreq() - find devfreq struct using device pointer
51 * @dev: device pointer used to lookup device devfreq.
52 *
53 * Search the list of device devfreqs and return the matched device's
54 * devfreq info. devfreq_list_lock should be held by the caller.
55 */
56static struct devfreq *find_device_devfreq(struct device *dev)
57{
58 struct devfreq *tmp_devfreq;
59
60 if (IS_ERR_OR_NULL(dev)) {
61 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
62 return ERR_PTR(-EINVAL);
63 }
64 WARN(!mutex_is_locked(&devfreq_list_lock),
65 "devfreq_list_lock must be locked.");
66
67 list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
68 if (tmp_devfreq->dev.parent == dev)
69 return tmp_devfreq;
70 }
71
72 return ERR_PTR(-ENODEV);
73}
74
75static unsigned long find_available_min_freq(struct devfreq *devfreq)
76{
77 struct dev_pm_opp *opp;
78 unsigned long min_freq = 0;
79
80 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
81 if (IS_ERR(opp))
82 min_freq = 0;
83 else
84 dev_pm_opp_put(opp);
85
86 return min_freq;
87}
88
89static unsigned long find_available_max_freq(struct devfreq *devfreq)
90{
91 struct dev_pm_opp *opp;
92 unsigned long max_freq = ULONG_MAX;
93
94 opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
95 if (IS_ERR(opp))
96 max_freq = 0;
97 else
98 dev_pm_opp_put(opp);
99
100 return max_freq;
101}
102
103/**
104 * devfreq_get_freq_level() - Lookup freq_table for the frequency
105 * @devfreq: the devfreq instance
106 * @freq: the target frequency
107 */
108static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
109{
110 int lev;
111
112 for (lev = 0; lev < devfreq->profile->max_state; lev++)
113 if (freq == devfreq->profile->freq_table[lev])
114 return lev;
115
116 return -EINVAL;
117}
118
119static int set_freq_table(struct devfreq *devfreq)
120{
121 struct devfreq_dev_profile *profile = devfreq->profile;
122 struct dev_pm_opp *opp;
123 unsigned long freq;
124 int i, count;
125
126 /* Initialize the freq_table from OPP table */
127 count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
128 if (count <= 0)
129 return -EINVAL;
130
131 profile->max_state = count;
132 profile->freq_table = devm_kcalloc(devfreq->dev.parent,
133 profile->max_state,
134 sizeof(*profile->freq_table),
135 GFP_KERNEL);
136 if (!profile->freq_table) {
137 profile->max_state = 0;
138 return -ENOMEM;
139 }
140
141 for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
142 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
143 if (IS_ERR(opp)) {
144 devm_kfree(devfreq->dev.parent, profile->freq_table);
145 profile->max_state = 0;
146 return PTR_ERR(opp);
147 }
148 dev_pm_opp_put(opp);
149 profile->freq_table[i] = freq;
150 }
151
152 return 0;
153}
154
155/**
156 * devfreq_update_status() - Update statistics of devfreq behavior
157 * @devfreq: the devfreq instance
158 * @freq: the update target frequency
159 */
160int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
161{
162 int lev, prev_lev, ret = 0;
163 unsigned long cur_time;
164
165 cur_time = jiffies;
166
167 /* Immediately exit if previous_freq is not initialized yet. */
168 if (!devfreq->previous_freq)
169 goto out;
170
171 prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
172 if (prev_lev < 0) {
173 ret = prev_lev;
174 goto out;
175 }
176
177 devfreq->time_in_state[prev_lev] +=
178 cur_time - devfreq->last_stat_updated;
179
180 lev = devfreq_get_freq_level(devfreq, freq);
181 if (lev < 0) {
182 ret = lev;
183 goto out;
184 }
185
186 if (lev != prev_lev) {
187 devfreq->trans_table[(prev_lev *
188 devfreq->profile->max_state) + lev]++;
189 devfreq->total_trans++;
190 }
191
192out:
193 devfreq->last_stat_updated = cur_time;
194 return ret;
195}
196EXPORT_SYMBOL(devfreq_update_status);
197
198/**
199 * find_devfreq_governor() - find devfreq governor from name
200 * @name: name of the governor
201 *
202 * Search the list of devfreq governors and return the matched
203 * governor's pointer. devfreq_list_lock should be held by the caller.
204 */
205static struct devfreq_governor *find_devfreq_governor(const char *name)
206{
207 struct devfreq_governor *tmp_governor;
208
209 if (IS_ERR_OR_NULL(name)) {
210 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
211 return ERR_PTR(-EINVAL);
212 }
213 WARN(!mutex_is_locked(&devfreq_list_lock),
214 "devfreq_list_lock must be locked.");
215
216 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
217 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
218 return tmp_governor;
219 }
220
221 return ERR_PTR(-ENODEV);
222}
223
224static int devfreq_notify_transition(struct devfreq *devfreq,
225 struct devfreq_freqs *freqs, unsigned int state)
226{
227 if (!devfreq)
228 return -EINVAL;
229
230 switch (state) {
231 case DEVFREQ_PRECHANGE:
232 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
233 DEVFREQ_PRECHANGE, freqs);
234 break;
235
236 case DEVFREQ_POSTCHANGE:
237 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
238 DEVFREQ_POSTCHANGE, freqs);
239 break;
240 default:
241 return -EINVAL;
242 }
243
244 return 0;
245}
246
247/* Load monitoring helper functions for governors use */
248
249/**
250 * update_devfreq() - Reevaluate the device and configure frequency.
251 * @devfreq: the devfreq instance.
252 *
253 * Note: Lock devfreq->lock before calling update_devfreq
254 * This function is exported for governors.
255 */
256int update_devfreq(struct devfreq *devfreq)
257{
258 struct devfreq_freqs freqs;
259 unsigned long freq, cur_freq, min_freq, max_freq;
260 int err = 0;
261 u32 flags = 0;
262
263 if (!mutex_is_locked(&devfreq->lock)) {
264 WARN(true, "devfreq->lock must be locked by the caller.\n");
265 return -EINVAL;
266 }
267
268 if (!devfreq->governor)
269 return -EINVAL;
270
271 /* Reevaluate the proper frequency */
272 err = devfreq->governor->get_target_freq(devfreq, &freq);
273 if (err)
274 return err;
275
276 /*
277 * Adjust the frequency with user freq, QoS and available freq.
278 *
279 * List from the highest priority
280 * max_freq
281 * min_freq
282 */
283 max_freq = MIN(devfreq->scaling_max_freq, devfreq->max_freq);
284 min_freq = MAX(devfreq->scaling_min_freq, devfreq->min_freq);
285
286 if (min_freq && freq < min_freq) {
287 freq = min_freq;
288 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
289 }
290 if (max_freq && freq > max_freq) {
291 freq = max_freq;
292 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
293 }
294
295 if (devfreq->profile->get_cur_freq)
296 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
297 else
298 cur_freq = devfreq->previous_freq;
299
300 freqs.old = cur_freq;
301 freqs.new = freq;
302 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
303
304 err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
305 if (err) {
306 freqs.new = cur_freq;
307 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
308 return err;
309 }
310
311 freqs.new = freq;
312 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
313
314 if (devfreq_update_status(devfreq, freq))
315 dev_err(&devfreq->dev,
316 "Couldn't update frequency transition information.\n");
317
318 devfreq->previous_freq = freq;
319 return err;
320}
321EXPORT_SYMBOL(update_devfreq);
322
323/**
324 * devfreq_monitor() - Periodically poll devfreq objects.
325 * @work: the work struct used to run devfreq_monitor periodically.
326 *
327 */
328static void devfreq_monitor(struct work_struct *work)
329{
330 int err;
331 struct devfreq *devfreq = container_of(work,
332 struct devfreq, work.work);
333
334 mutex_lock(&devfreq->lock);
335 err = update_devfreq(devfreq);
336 if (err)
337 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
338
339 queue_delayed_work(devfreq_wq, &devfreq->work,
340 msecs_to_jiffies(devfreq->profile->polling_ms));
341 mutex_unlock(&devfreq->lock);
342}
343
344/**
345 * devfreq_monitor_start() - Start load monitoring of devfreq instance
346 * @devfreq: the devfreq instance.
347 *
348 * Helper function for starting devfreq device load monitoing. By
349 * default delayed work based monitoring is supported. Function
350 * to be called from governor in response to DEVFREQ_GOV_START
351 * event when device is added to devfreq framework.
352 */
353void devfreq_monitor_start(struct devfreq *devfreq)
354{
355 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
356 if (devfreq->profile->polling_ms)
357 queue_delayed_work(devfreq_wq, &devfreq->work,
358 msecs_to_jiffies(devfreq->profile->polling_ms));
359}
360EXPORT_SYMBOL(devfreq_monitor_start);
361
362/**
363 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
364 * @devfreq: the devfreq instance.
365 *
366 * Helper function to stop devfreq device load monitoing. Function
367 * to be called from governor in response to DEVFREQ_GOV_STOP
368 * event when device is removed from devfreq framework.
369 */
370void devfreq_monitor_stop(struct devfreq *devfreq)
371{
372 cancel_delayed_work_sync(&devfreq->work);
373}
374EXPORT_SYMBOL(devfreq_monitor_stop);
375
376/**
377 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
378 * @devfreq: the devfreq instance.
379 *
380 * Helper function to suspend devfreq device load monitoing. Function
381 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
382 * event or when polling interval is set to zero.
383 *
384 * Note: Though this function is same as devfreq_monitor_stop(),
385 * intentionally kept separate to provide hooks for collecting
386 * transition statistics.
387 */
388void devfreq_monitor_suspend(struct devfreq *devfreq)
389{
390 mutex_lock(&devfreq->lock);
391 if (devfreq->stop_polling) {
392 mutex_unlock(&devfreq->lock);
393 return;
394 }
395
396 devfreq_update_status(devfreq, devfreq->previous_freq);
397 devfreq->stop_polling = true;
398 mutex_unlock(&devfreq->lock);
399 cancel_delayed_work_sync(&devfreq->work);
400}
401EXPORT_SYMBOL(devfreq_monitor_suspend);
402
403/**
404 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
405 * @devfreq: the devfreq instance.
406 *
407 * Helper function to resume devfreq device load monitoing. Function
408 * to be called from governor in response to DEVFREQ_GOV_RESUME
409 * event or when polling interval is set to non-zero.
410 */
411void devfreq_monitor_resume(struct devfreq *devfreq)
412{
413 unsigned long freq;
414
415 mutex_lock(&devfreq->lock);
416 if (!devfreq->stop_polling)
417 goto out;
418
419 if (!delayed_work_pending(&devfreq->work) &&
420 devfreq->profile->polling_ms)
421 queue_delayed_work(devfreq_wq, &devfreq->work,
422 msecs_to_jiffies(devfreq->profile->polling_ms));
423
424 devfreq->last_stat_updated = jiffies;
425 devfreq->stop_polling = false;
426
427 if (devfreq->profile->get_cur_freq &&
428 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
429 devfreq->previous_freq = freq;
430
431out:
432 mutex_unlock(&devfreq->lock);
433}
434EXPORT_SYMBOL(devfreq_monitor_resume);
435
436/**
437 * devfreq_interval_update() - Update device devfreq monitoring interval
438 * @devfreq: the devfreq instance.
439 * @delay: new polling interval to be set.
440 *
441 * Helper function to set new load monitoring polling interval. Function
442 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
443 */
444void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
445{
446 unsigned int cur_delay = devfreq->profile->polling_ms;
447 unsigned int new_delay = *delay;
448
449 mutex_lock(&devfreq->lock);
450 devfreq->profile->polling_ms = new_delay;
451
452 if (devfreq->stop_polling)
453 goto out;
454
455 /* if new delay is zero, stop polling */
456 if (!new_delay) {
457 mutex_unlock(&devfreq->lock);
458 cancel_delayed_work_sync(&devfreq->work);
459 return;
460 }
461
462 /* if current delay is zero, start polling with new delay */
463 if (!cur_delay) {
464 queue_delayed_work(devfreq_wq, &devfreq->work,
465 msecs_to_jiffies(devfreq->profile->polling_ms));
466 goto out;
467 }
468
469 /* if current delay is greater than new delay, restart polling */
470 if (cur_delay > new_delay) {
471 mutex_unlock(&devfreq->lock);
472 cancel_delayed_work_sync(&devfreq->work);
473 mutex_lock(&devfreq->lock);
474 if (!devfreq->stop_polling)
475 queue_delayed_work(devfreq_wq, &devfreq->work,
476 msecs_to_jiffies(devfreq->profile->polling_ms));
477 }
478out:
479 mutex_unlock(&devfreq->lock);
480}
481EXPORT_SYMBOL(devfreq_interval_update);
482
483/**
484 * devfreq_notifier_call() - Notify that the device frequency requirements
485 * has been changed out of devfreq framework.
486 * @nb: the notifier_block (supposed to be devfreq->nb)
487 * @type: not used
488 * @devp: not used
489 *
490 * Called by a notifier that uses devfreq->nb.
491 */
492static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
493 void *devp)
494{
495 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
496 int ret;
497
498 mutex_lock(&devfreq->lock);
499
500 devfreq->scaling_min_freq = find_available_min_freq(devfreq);
501 if (!devfreq->scaling_min_freq) {
502 mutex_unlock(&devfreq->lock);
503 return -EINVAL;
504 }
505
506 devfreq->scaling_max_freq = find_available_max_freq(devfreq);
507 if (!devfreq->scaling_max_freq) {
508 mutex_unlock(&devfreq->lock);
509 return -EINVAL;
510 }
511
512 ret = update_devfreq(devfreq);
513 mutex_unlock(&devfreq->lock);
514
515 return ret;
516}
517
518/**
519 * devfreq_dev_release() - Callback for struct device to release the device.
520 * @dev: the devfreq device
521 *
522 * Remove devfreq from the list and release its resources.
523 */
524static void devfreq_dev_release(struct device *dev)
525{
526 struct devfreq *devfreq = to_devfreq(dev);
527
528 mutex_lock(&devfreq_list_lock);
529 if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
530 mutex_unlock(&devfreq_list_lock);
531 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
532 return;
533 }
534 list_del(&devfreq->node);
535 mutex_unlock(&devfreq_list_lock);
536
537 if (devfreq->governor)
538 devfreq->governor->event_handler(devfreq,
539 DEVFREQ_GOV_STOP, NULL);
540
541 if (devfreq->profile->exit)
542 devfreq->profile->exit(devfreq->dev.parent);
543
544 mutex_destroy(&devfreq->lock);
545 kfree(devfreq);
546}
547
548/**
549 * devfreq_add_device() - Add devfreq feature to the device
550 * @dev: the device to add devfreq feature.
551 * @profile: device-specific profile to run devfreq.
552 * @governor_name: name of the policy to choose frequency.
553 * @data: private data for the governor. The devfreq framework does not
554 * touch this value.
555 */
556struct devfreq *devfreq_add_device(struct device *dev,
557 struct devfreq_dev_profile *profile,
558 const char *governor_name,
559 void *data)
560{
561 struct devfreq *devfreq;
562 struct devfreq_governor *governor;
563 static atomic_t devfreq_no = ATOMIC_INIT(-1);
564 int err = 0;
565
566 if (!dev || !profile || !governor_name) {
567 dev_err(dev, "%s: Invalid parameters.\n", __func__);
568 return ERR_PTR(-EINVAL);
569 }
570
571 mutex_lock(&devfreq_list_lock);
572 devfreq = find_device_devfreq(dev);
573 mutex_unlock(&devfreq_list_lock);
574 if (!IS_ERR(devfreq)) {
575 dev_err(dev, "%s: Unable to create devfreq for the device.\n",
576 __func__);
577 err = -EINVAL;
578 goto err_out;
579 }
580
581 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
582 if (!devfreq) {
583 err = -ENOMEM;
584 goto err_out;
585 }
586
587 mutex_init(&devfreq->lock);
588 mutex_lock(&devfreq->lock);
589 devfreq->dev.parent = dev;
590 devfreq->dev.class = devfreq_class;
591 devfreq->dev.release = devfreq_dev_release;
592 devfreq->profile = profile;
593 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
594 devfreq->previous_freq = profile->initial_freq;
595 devfreq->last_status.current_frequency = profile->initial_freq;
596 devfreq->data = data;
597 devfreq->nb.notifier_call = devfreq_notifier_call;
598
599 if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
600 mutex_unlock(&devfreq->lock);
601 err = set_freq_table(devfreq);
602 if (err < 0)
603 goto err_out;
604 mutex_lock(&devfreq->lock);
605 }
606
607 devfreq->min_freq = find_available_min_freq(devfreq);
608 if (!devfreq->min_freq) {
609 mutex_unlock(&devfreq->lock);
610 err = -EINVAL;
611 goto err_dev;
612 }
613 devfreq->scaling_min_freq = devfreq->min_freq;
614
615 devfreq->max_freq = find_available_max_freq(devfreq);
616 if (!devfreq->max_freq) {
617 mutex_unlock(&devfreq->lock);
618 err = -EINVAL;
619 goto err_dev;
620 }
621 devfreq->scaling_max_freq = devfreq->max_freq;
622
623 dev_set_name(&devfreq->dev, "devfreq%d",
624 atomic_inc_return(&devfreq_no));
625 err = device_register(&devfreq->dev);
626 if (err) {
627 mutex_unlock(&devfreq->lock);
628 goto err_dev;
629 }
630
631 devfreq->trans_table = devm_kzalloc(&devfreq->dev,
632 sizeof(unsigned int) *
633 devfreq->profile->max_state *
634 devfreq->profile->max_state,
635 GFP_KERNEL);
636 devfreq->time_in_state = devm_kzalloc(&devfreq->dev,
637 sizeof(unsigned long) *
638 devfreq->profile->max_state,
639 GFP_KERNEL);
640 devfreq->last_stat_updated = jiffies;
641
642 srcu_init_notifier_head(&devfreq->transition_notifier_list);
643
644 mutex_unlock(&devfreq->lock);
645
646 mutex_lock(&devfreq_list_lock);
647 list_add(&devfreq->node, &devfreq_list);
648
649 governor = find_devfreq_governor(devfreq->governor_name);
650 if (IS_ERR(governor)) {
651 dev_err(dev, "%s: Unable to find governor for the device\n",
652 __func__);
653 err = PTR_ERR(governor);
654 goto err_init;
655 }
656
657 devfreq->governor = governor;
658 err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
659 NULL);
660 if (err) {
661 dev_err(dev, "%s: Unable to start governor for the device\n",
662 __func__);
663 goto err_init;
664 }
665 mutex_unlock(&devfreq_list_lock);
666
667 return devfreq;
668
669err_init:
670 list_del(&devfreq->node);
671 mutex_unlock(&devfreq_list_lock);
672
673 device_unregister(&devfreq->dev);
674err_dev:
675 if (devfreq)
676 kfree(devfreq);
677err_out:
678 return ERR_PTR(err);
679}
680EXPORT_SYMBOL(devfreq_add_device);
681
682/**
683 * devfreq_remove_device() - Remove devfreq feature from a device.
684 * @devfreq: the devfreq instance to be removed
685 *
686 * The opposite of devfreq_add_device().
687 */
688int devfreq_remove_device(struct devfreq *devfreq)
689{
690 if (!devfreq)
691 return -EINVAL;
692
693 device_unregister(&devfreq->dev);
694
695 return 0;
696}
697EXPORT_SYMBOL(devfreq_remove_device);
698
699static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
700{
701 struct devfreq **r = res;
702
703 if (WARN_ON(!r || !*r))
704 return 0;
705
706 return *r == data;
707}
708
709static void devm_devfreq_dev_release(struct device *dev, void *res)
710{
711 devfreq_remove_device(*(struct devfreq **)res);
712}
713
714/**
715 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
716 * @dev: the device to add devfreq feature.
717 * @profile: device-specific profile to run devfreq.
718 * @governor_name: name of the policy to choose frequency.
719 * @data: private data for the governor. The devfreq framework does not
720 * touch this value.
721 *
722 * This function manages automatically the memory of devfreq device using device
723 * resource management and simplify the free operation for memory of devfreq
724 * device.
725 */
726struct devfreq *devm_devfreq_add_device(struct device *dev,
727 struct devfreq_dev_profile *profile,
728 const char *governor_name,
729 void *data)
730{
731 struct devfreq **ptr, *devfreq;
732
733 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
734 if (!ptr)
735 return ERR_PTR(-ENOMEM);
736
737 devfreq = devfreq_add_device(dev, profile, governor_name, data);
738 if (IS_ERR(devfreq)) {
739 devres_free(ptr);
740 return devfreq;
741 }
742
743 *ptr = devfreq;
744 devres_add(dev, ptr);
745
746 return devfreq;
747}
748EXPORT_SYMBOL(devm_devfreq_add_device);
749
750#ifdef CONFIG_OF
751/*
752 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
753 * @dev - instance to the given device
754 * @index - index into list of devfreq
755 *
756 * return the instance of devfreq device
757 */
758struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
759{
760 struct device_node *node;
761 struct devfreq *devfreq;
762
763 if (!dev)
764 return ERR_PTR(-EINVAL);
765
766 if (!dev->of_node)
767 return ERR_PTR(-EINVAL);
768
769 node = of_parse_phandle(dev->of_node, "devfreq", index);
770 if (!node)
771 return ERR_PTR(-ENODEV);
772
773 mutex_lock(&devfreq_list_lock);
774 list_for_each_entry(devfreq, &devfreq_list, node) {
775 if (devfreq->dev.parent
776 && devfreq->dev.parent->of_node == node) {
777 mutex_unlock(&devfreq_list_lock);
778 of_node_put(node);
779 return devfreq;
780 }
781 }
782 mutex_unlock(&devfreq_list_lock);
783 of_node_put(node);
784
785 return ERR_PTR(-EPROBE_DEFER);
786}
787#else
788struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
789{
790 return ERR_PTR(-ENODEV);
791}
792#endif /* CONFIG_OF */
793EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
794
795/**
796 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
797 * @dev: the device to add devfreq feature.
798 * @devfreq: the devfreq instance to be removed
799 */
800void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
801{
802 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
803 devm_devfreq_dev_match, devfreq));
804}
805EXPORT_SYMBOL(devm_devfreq_remove_device);
806
807/**
808 * devfreq_suspend_device() - Suspend devfreq of a device.
809 * @devfreq: the devfreq instance to be suspended
810 *
811 * This function is intended to be called by the pm callbacks
812 * (e.g., runtime_suspend, suspend) of the device driver that
813 * holds the devfreq.
814 */
815int devfreq_suspend_device(struct devfreq *devfreq)
816{
817 if (!devfreq)
818 return -EINVAL;
819
820 if (!devfreq->governor)
821 return 0;
822
823 return devfreq->governor->event_handler(devfreq,
824 DEVFREQ_GOV_SUSPEND, NULL);
825}
826EXPORT_SYMBOL(devfreq_suspend_device);
827
828/**
829 * devfreq_resume_device() - Resume devfreq of a device.
830 * @devfreq: the devfreq instance to be resumed
831 *
832 * This function is intended to be called by the pm callbacks
833 * (e.g., runtime_resume, resume) of the device driver that
834 * holds the devfreq.
835 */
836int devfreq_resume_device(struct devfreq *devfreq)
837{
838 if (!devfreq)
839 return -EINVAL;
840
841 if (!devfreq->governor)
842 return 0;
843
844 return devfreq->governor->event_handler(devfreq,
845 DEVFREQ_GOV_RESUME, NULL);
846}
847EXPORT_SYMBOL(devfreq_resume_device);
848
849/**
850 * devfreq_add_governor() - Add devfreq governor
851 * @governor: the devfreq governor to be added
852 */
853int devfreq_add_governor(struct devfreq_governor *governor)
854{
855 struct devfreq_governor *g;
856 struct devfreq *devfreq;
857 int err = 0;
858
859 if (!governor) {
860 pr_err("%s: Invalid parameters.\n", __func__);
861 return -EINVAL;
862 }
863
864 mutex_lock(&devfreq_list_lock);
865 g = find_devfreq_governor(governor->name);
866 if (!IS_ERR(g)) {
867 pr_err("%s: governor %s already registered\n", __func__,
868 g->name);
869 err = -EINVAL;
870 goto err_out;
871 }
872
873 list_add(&governor->node, &devfreq_governor_list);
874
875 list_for_each_entry(devfreq, &devfreq_list, node) {
876 int ret = 0;
877 struct device *dev = devfreq->dev.parent;
878
879 if (!strncmp(devfreq->governor_name, governor->name,
880 DEVFREQ_NAME_LEN)) {
881 /* The following should never occur */
882 if (devfreq->governor) {
883 dev_warn(dev,
884 "%s: Governor %s already present\n",
885 __func__, devfreq->governor->name);
886 ret = devfreq->governor->event_handler(devfreq,
887 DEVFREQ_GOV_STOP, NULL);
888 if (ret) {
889 dev_warn(dev,
890 "%s: Governor %s stop = %d\n",
891 __func__,
892 devfreq->governor->name, ret);
893 }
894 /* Fall through */
895 }
896 devfreq->governor = governor;
897 ret = devfreq->governor->event_handler(devfreq,
898 DEVFREQ_GOV_START, NULL);
899 if (ret) {
900 dev_warn(dev, "%s: Governor %s start=%d\n",
901 __func__, devfreq->governor->name,
902 ret);
903 }
904 }
905 }
906
907err_out:
908 mutex_unlock(&devfreq_list_lock);
909
910 return err;
911}
912EXPORT_SYMBOL(devfreq_add_governor);
913
914/**
915 * devfreq_remove_governor() - Remove devfreq feature from a device.
916 * @governor: the devfreq governor to be removed
917 */
918int devfreq_remove_governor(struct devfreq_governor *governor)
919{
920 struct devfreq_governor *g;
921 struct devfreq *devfreq;
922 int err = 0;
923
924 if (!governor) {
925 pr_err("%s: Invalid parameters.\n", __func__);
926 return -EINVAL;
927 }
928
929 mutex_lock(&devfreq_list_lock);
930 g = find_devfreq_governor(governor->name);
931 if (IS_ERR(g)) {
932 pr_err("%s: governor %s not registered\n", __func__,
933 governor->name);
934 err = PTR_ERR(g);
935 goto err_out;
936 }
937 list_for_each_entry(devfreq, &devfreq_list, node) {
938 int ret;
939 struct device *dev = devfreq->dev.parent;
940
941 if (!strncmp(devfreq->governor_name, governor->name,
942 DEVFREQ_NAME_LEN)) {
943 /* we should have a devfreq governor! */
944 if (!devfreq->governor) {
945 dev_warn(dev, "%s: Governor %s NOT present\n",
946 __func__, governor->name);
947 continue;
948 /* Fall through */
949 }
950 ret = devfreq->governor->event_handler(devfreq,
951 DEVFREQ_GOV_STOP, NULL);
952 if (ret) {
953 dev_warn(dev, "%s: Governor %s stop=%d\n",
954 __func__, devfreq->governor->name,
955 ret);
956 }
957 devfreq->governor = NULL;
958 }
959 }
960
961 list_del(&governor->node);
962err_out:
963 mutex_unlock(&devfreq_list_lock);
964
965 return err;
966}
967EXPORT_SYMBOL(devfreq_remove_governor);
968
969static ssize_t governor_show(struct device *dev,
970 struct device_attribute *attr, char *buf)
971{
972 if (!to_devfreq(dev)->governor)
973 return -EINVAL;
974
975 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
976}
977
978static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
979 const char *buf, size_t count)
980{
981 struct devfreq *df = to_devfreq(dev);
982 int ret;
983 char str_governor[DEVFREQ_NAME_LEN + 1];
984 struct devfreq_governor *governor;
985
986 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
987 if (ret != 1)
988 return -EINVAL;
989
990 mutex_lock(&devfreq_list_lock);
991 governor = find_devfreq_governor(str_governor);
992 if (IS_ERR(governor)) {
993 ret = PTR_ERR(governor);
994 goto out;
995 }
996 if (df->governor == governor) {
997 ret = 0;
998 goto out;
999 } else if ((df->governor && df->governor->immutable) ||
1000 governor->immutable) {
1001 ret = -EINVAL;
1002 goto out;
1003 }
1004
1005 if (df->governor) {
1006 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1007 if (ret) {
1008 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1009 __func__, df->governor->name, ret);
1010 goto out;
1011 }
1012 }
1013 df->governor = governor;
1014 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1015 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1016 if (ret)
1017 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1018 __func__, df->governor->name, ret);
1019out:
1020 mutex_unlock(&devfreq_list_lock);
1021
1022 if (!ret)
1023 ret = count;
1024 return ret;
1025}
1026static DEVICE_ATTR_RW(governor);
1027
1028static ssize_t available_governors_show(struct device *d,
1029 struct device_attribute *attr,
1030 char *buf)
1031{
1032 struct devfreq *df = to_devfreq(d);
1033 ssize_t count = 0;
1034
1035 mutex_lock(&devfreq_list_lock);
1036
1037 /*
1038 * The devfreq with immutable governor (e.g., passive) shows
1039 * only own governor.
1040 */
1041 if (df->governor->immutable) {
1042 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1043 "%s ", df->governor_name);
1044 /*
1045 * The devfreq device shows the registered governor except for
1046 * immutable governors such as passive governor .
1047 */
1048 } else {
1049 struct devfreq_governor *governor;
1050
1051 list_for_each_entry(governor, &devfreq_governor_list, node) {
1052 if (governor->immutable)
1053 continue;
1054 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1055 "%s ", governor->name);
1056 }
1057 }
1058
1059 mutex_unlock(&devfreq_list_lock);
1060
1061 /* Truncate the trailing space */
1062 if (count)
1063 count--;
1064
1065 count += sprintf(&buf[count], "\n");
1066
1067 return count;
1068}
1069static DEVICE_ATTR_RO(available_governors);
1070
1071static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1072 char *buf)
1073{
1074 unsigned long freq;
1075 struct devfreq *devfreq = to_devfreq(dev);
1076
1077 if (devfreq->profile->get_cur_freq &&
1078 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1079 return sprintf(buf, "%lu\n", freq);
1080
1081 return sprintf(buf, "%lu\n", devfreq->previous_freq);
1082}
1083static DEVICE_ATTR_RO(cur_freq);
1084
1085static ssize_t target_freq_show(struct device *dev,
1086 struct device_attribute *attr, char *buf)
1087{
1088 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1089}
1090static DEVICE_ATTR_RO(target_freq);
1091
1092static ssize_t polling_interval_show(struct device *dev,
1093 struct device_attribute *attr, char *buf)
1094{
1095 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1096}
1097
1098static ssize_t polling_interval_store(struct device *dev,
1099 struct device_attribute *attr,
1100 const char *buf, size_t count)
1101{
1102 struct devfreq *df = to_devfreq(dev);
1103 unsigned int value;
1104 int ret;
1105
1106 if (!df->governor)
1107 return -EINVAL;
1108
1109 ret = sscanf(buf, "%u", &value);
1110 if (ret != 1)
1111 return -EINVAL;
1112
1113 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1114 ret = count;
1115
1116 return ret;
1117}
1118static DEVICE_ATTR_RW(polling_interval);
1119
1120static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1121 const char *buf, size_t count)
1122{
1123 struct devfreq *df = to_devfreq(dev);
1124 unsigned long value;
1125 int ret;
1126 unsigned long max;
1127
1128 ret = sscanf(buf, "%lu", &value);
1129 if (ret != 1)
1130 return -EINVAL;
1131
1132 mutex_lock(&df->lock);
1133 max = df->max_freq;
1134 if (value && max && value > max) {
1135 ret = -EINVAL;
1136 goto unlock;
1137 }
1138
1139 df->min_freq = value;
1140 update_devfreq(df);
1141 ret = count;
1142unlock:
1143 mutex_unlock(&df->lock);
1144 return ret;
1145}
1146
1147static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1148 char *buf)
1149{
1150 struct devfreq *df = to_devfreq(dev);
1151
1152 return sprintf(buf, "%lu\n", MAX(df->scaling_min_freq, df->min_freq));
1153}
1154
1155static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1156 const char *buf, size_t count)
1157{
1158 struct devfreq *df = to_devfreq(dev);
1159 unsigned long value;
1160 int ret;
1161 unsigned long min;
1162
1163 ret = sscanf(buf, "%lu", &value);
1164 if (ret != 1)
1165 return -EINVAL;
1166
1167 mutex_lock(&df->lock);
1168 min = df->min_freq;
1169 if (value && min && value < min) {
1170 ret = -EINVAL;
1171 goto unlock;
1172 }
1173
1174 df->max_freq = value;
1175 update_devfreq(df);
1176 ret = count;
1177unlock:
1178 mutex_unlock(&df->lock);
1179 return ret;
1180}
1181static DEVICE_ATTR_RW(min_freq);
1182
1183static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1184 char *buf)
1185{
1186 struct devfreq *df = to_devfreq(dev);
1187
1188 return sprintf(buf, "%lu\n", MIN(df->scaling_max_freq, df->max_freq));
1189}
1190static DEVICE_ATTR_RW(max_freq);
1191
1192static ssize_t available_frequencies_show(struct device *d,
1193 struct device_attribute *attr,
1194 char *buf)
1195{
1196 struct devfreq *df = to_devfreq(d);
1197 ssize_t count = 0;
1198 int i;
1199
1200 mutex_lock(&df->lock);
1201
1202 for (i = 0; i < df->profile->max_state; i++)
1203 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1204 "%lu ", df->profile->freq_table[i]);
1205
1206 mutex_unlock(&df->lock);
1207 /* Truncate the trailing space */
1208 if (count)
1209 count--;
1210
1211 count += sprintf(&buf[count], "\n");
1212
1213 return count;
1214}
1215static DEVICE_ATTR_RO(available_frequencies);
1216
1217static ssize_t trans_stat_show(struct device *dev,
1218 struct device_attribute *attr, char *buf)
1219{
1220 struct devfreq *devfreq = to_devfreq(dev);
1221 ssize_t len;
1222 int i, j;
1223 unsigned int max_state = devfreq->profile->max_state;
1224
1225 if (!devfreq->stop_polling &&
1226 devfreq_update_status(devfreq, devfreq->previous_freq))
1227 return 0;
1228 if (max_state == 0)
1229 return sprintf(buf, "Not Supported.\n");
1230
1231 len = sprintf(buf, " From : To\n");
1232 len += sprintf(buf + len, " :");
1233 for (i = 0; i < max_state; i++)
1234 len += sprintf(buf + len, "%10lu",
1235 devfreq->profile->freq_table[i]);
1236
1237 len += sprintf(buf + len, " time(ms)\n");
1238
1239 for (i = 0; i < max_state; i++) {
1240 if (devfreq->profile->freq_table[i]
1241 == devfreq->previous_freq) {
1242 len += sprintf(buf + len, "*");
1243 } else {
1244 len += sprintf(buf + len, " ");
1245 }
1246 len += sprintf(buf + len, "%10lu:",
1247 devfreq->profile->freq_table[i]);
1248 for (j = 0; j < max_state; j++)
1249 len += sprintf(buf + len, "%10u",
1250 devfreq->trans_table[(i * max_state) + j]);
1251 len += sprintf(buf + len, "%10u\n",
1252 jiffies_to_msecs(devfreq->time_in_state[i]));
1253 }
1254
1255 len += sprintf(buf + len, "Total transition : %u\n",
1256 devfreq->total_trans);
1257 return len;
1258}
1259static DEVICE_ATTR_RO(trans_stat);
1260
1261static struct attribute *devfreq_attrs[] = {
1262 &dev_attr_governor.attr,
1263 &dev_attr_available_governors.attr,
1264 &dev_attr_cur_freq.attr,
1265 &dev_attr_available_frequencies.attr,
1266 &dev_attr_target_freq.attr,
1267 &dev_attr_polling_interval.attr,
1268 &dev_attr_min_freq.attr,
1269 &dev_attr_max_freq.attr,
1270 &dev_attr_trans_stat.attr,
1271 NULL,
1272};
1273ATTRIBUTE_GROUPS(devfreq);
1274
1275static int __init devfreq_init(void)
1276{
1277 devfreq_class = class_create(THIS_MODULE, "devfreq");
1278 if (IS_ERR(devfreq_class)) {
1279 pr_err("%s: couldn't create class\n", __FILE__);
1280 return PTR_ERR(devfreq_class);
1281 }
1282
1283 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1284 if (!devfreq_wq) {
1285 class_destroy(devfreq_class);
1286 pr_err("%s: couldn't create workqueue\n", __FILE__);
1287 return -ENOMEM;
1288 }
1289 devfreq_class->dev_groups = devfreq_groups;
1290
1291 return 0;
1292}
1293subsys_initcall(devfreq_init);
1294
1295/*
1296 * The following are helper functions for devfreq user device drivers with
1297 * OPP framework.
1298 */
1299
1300/**
1301 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1302 * freq value given to target callback.
1303 * @dev: The devfreq user device. (parent of devfreq)
1304 * @freq: The frequency given to target function
1305 * @flags: Flags handed from devfreq framework.
1306 *
1307 * The callers are required to call dev_pm_opp_put() for the returned OPP after
1308 * use.
1309 */
1310struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1311 unsigned long *freq,
1312 u32 flags)
1313{
1314 struct dev_pm_opp *opp;
1315
1316 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1317 /* The freq is an upper bound. opp should be lower */
1318 opp = dev_pm_opp_find_freq_floor(dev, freq);
1319
1320 /* If not available, use the closest opp */
1321 if (opp == ERR_PTR(-ERANGE))
1322 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1323 } else {
1324 /* The freq is an lower bound. opp should be higher */
1325 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1326
1327 /* If not available, use the closest opp */
1328 if (opp == ERR_PTR(-ERANGE))
1329 opp = dev_pm_opp_find_freq_floor(dev, freq);
1330 }
1331
1332 return opp;
1333}
1334EXPORT_SYMBOL(devfreq_recommended_opp);
1335
1336/**
1337 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1338 * for any changes in the OPP availability
1339 * changes
1340 * @dev: The devfreq user device. (parent of devfreq)
1341 * @devfreq: The devfreq object.
1342 */
1343int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1344{
1345 return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1346}
1347EXPORT_SYMBOL(devfreq_register_opp_notifier);
1348
1349/**
1350 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1351 * notified for any changes in the OPP
1352 * availability changes anymore.
1353 * @dev: The devfreq user device. (parent of devfreq)
1354 * @devfreq: The devfreq object.
1355 *
1356 * At exit() callback of devfreq_dev_profile, this must be included if
1357 * devfreq_recommended_opp is used.
1358 */
1359int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1360{
1361 return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1362}
1363EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1364
1365static void devm_devfreq_opp_release(struct device *dev, void *res)
1366{
1367 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1368}
1369
1370/**
1371 * devm_ devfreq_register_opp_notifier()
1372 * - Resource-managed devfreq_register_opp_notifier()
1373 * @dev: The devfreq user device. (parent of devfreq)
1374 * @devfreq: The devfreq object.
1375 */
1376int devm_devfreq_register_opp_notifier(struct device *dev,
1377 struct devfreq *devfreq)
1378{
1379 struct devfreq **ptr;
1380 int ret;
1381
1382 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1383 if (!ptr)
1384 return -ENOMEM;
1385
1386 ret = devfreq_register_opp_notifier(dev, devfreq);
1387 if (ret) {
1388 devres_free(ptr);
1389 return ret;
1390 }
1391
1392 *ptr = devfreq;
1393 devres_add(dev, ptr);
1394
1395 return 0;
1396}
1397EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1398
1399/**
1400 * devm_devfreq_unregister_opp_notifier()
1401 * - Resource-managed devfreq_unregister_opp_notifier()
1402 * @dev: The devfreq user device. (parent of devfreq)
1403 * @devfreq: The devfreq object.
1404 */
1405void devm_devfreq_unregister_opp_notifier(struct device *dev,
1406 struct devfreq *devfreq)
1407{
1408 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1409 devm_devfreq_dev_match, devfreq));
1410}
1411EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1412
1413/**
1414 * devfreq_register_notifier() - Register a driver with devfreq
1415 * @devfreq: The devfreq object.
1416 * @nb: The notifier block to register.
1417 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1418 */
1419int devfreq_register_notifier(struct devfreq *devfreq,
1420 struct notifier_block *nb,
1421 unsigned int list)
1422{
1423 int ret = 0;
1424
1425 if (!devfreq)
1426 return -EINVAL;
1427
1428 switch (list) {
1429 case DEVFREQ_TRANSITION_NOTIFIER:
1430 ret = srcu_notifier_chain_register(
1431 &devfreq->transition_notifier_list, nb);
1432 break;
1433 default:
1434 ret = -EINVAL;
1435 }
1436
1437 return ret;
1438}
1439EXPORT_SYMBOL(devfreq_register_notifier);
1440
1441/*
1442 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1443 * @devfreq: The devfreq object.
1444 * @nb: The notifier block to be unregistered.
1445 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1446 */
1447int devfreq_unregister_notifier(struct devfreq *devfreq,
1448 struct notifier_block *nb,
1449 unsigned int list)
1450{
1451 int ret = 0;
1452
1453 if (!devfreq)
1454 return -EINVAL;
1455
1456 switch (list) {
1457 case DEVFREQ_TRANSITION_NOTIFIER:
1458 ret = srcu_notifier_chain_unregister(
1459 &devfreq->transition_notifier_list, nb);
1460 break;
1461 default:
1462 ret = -EINVAL;
1463 }
1464
1465 return ret;
1466}
1467EXPORT_SYMBOL(devfreq_unregister_notifier);
1468
1469struct devfreq_notifier_devres {
1470 struct devfreq *devfreq;
1471 struct notifier_block *nb;
1472 unsigned int list;
1473};
1474
1475static void devm_devfreq_notifier_release(struct device *dev, void *res)
1476{
1477 struct devfreq_notifier_devres *this = res;
1478
1479 devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1480}
1481
1482/**
1483 * devm_devfreq_register_notifier()
1484 - Resource-managed devfreq_register_notifier()
1485 * @dev: The devfreq user device. (parent of devfreq)
1486 * @devfreq: The devfreq object.
1487 * @nb: The notifier block to be unregistered.
1488 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1489 */
1490int devm_devfreq_register_notifier(struct device *dev,
1491 struct devfreq *devfreq,
1492 struct notifier_block *nb,
1493 unsigned int list)
1494{
1495 struct devfreq_notifier_devres *ptr;
1496 int ret;
1497
1498 ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1499 GFP_KERNEL);
1500 if (!ptr)
1501 return -ENOMEM;
1502
1503 ret = devfreq_register_notifier(devfreq, nb, list);
1504 if (ret) {
1505 devres_free(ptr);
1506 return ret;
1507 }
1508
1509 ptr->devfreq = devfreq;
1510 ptr->nb = nb;
1511 ptr->list = list;
1512 devres_add(dev, ptr);
1513
1514 return 0;
1515}
1516EXPORT_SYMBOL(devm_devfreq_register_notifier);
1517
1518/**
1519 * devm_devfreq_unregister_notifier()
1520 - Resource-managed devfreq_unregister_notifier()
1521 * @dev: The devfreq user device. (parent of devfreq)
1522 * @devfreq: The devfreq object.
1523 * @nb: The notifier block to be unregistered.
1524 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1525 */
1526void devm_devfreq_unregister_notifier(struct device *dev,
1527 struct devfreq *devfreq,
1528 struct notifier_block *nb,
1529 unsigned int list)
1530{
1531 WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1532 devm_devfreq_dev_match, devfreq));
1533}
1534EXPORT_SYMBOL(devm_devfreq_unregister_notifier);