projects/linux·blob v4.18 · refs

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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 <[email protected]>
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 =
632 devm_kzalloc(&devfreq->dev,
633 array3_size(sizeof(unsigned int),
634 devfreq->profile->max_state,
635 devfreq->profile->max_state),
636 GFP_KERNEL);
637 devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
638 devfreq->profile->max_state,
639 sizeof(unsigned long),
640 GFP_KERNEL);
641 devfreq->last_stat_updated = jiffies;
642
643 srcu_init_notifier_head(&devfreq->transition_notifier_list);
644
645 mutex_unlock(&devfreq->lock);
646
647 mutex_lock(&devfreq_list_lock);
648 list_add(&devfreq->node, &devfreq_list);
649
650 governor = find_devfreq_governor(devfreq->governor_name);
651 if (IS_ERR(governor)) {
652 dev_err(dev, "%s: Unable to find governor for the device\n",
653 __func__);
654 err = PTR_ERR(governor);
655 goto err_init;
656 }
657
658 devfreq->governor = governor;
659 err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
660 NULL);
661 if (err) {
662 dev_err(dev, "%s: Unable to start governor for the device\n",
663 __func__);
664 goto err_init;
665 }
666 mutex_unlock(&devfreq_list_lock);
667
668 return devfreq;
669
670err_init:
671 list_del(&devfreq->node);
672 mutex_unlock(&devfreq_list_lock);
673
674 device_unregister(&devfreq->dev);
675err_dev:
676 if (devfreq)
677 kfree(devfreq);
678err_out:
679 return ERR_PTR(err);
680}
681EXPORT_SYMBOL(devfreq_add_device);
682
683/**
684 * devfreq_remove_device() - Remove devfreq feature from a device.
685 * @devfreq: the devfreq instance to be removed
686 *
687 * The opposite of devfreq_add_device().
688 */
689int devfreq_remove_device(struct devfreq *devfreq)
690{
691 if (!devfreq)
692 return -EINVAL;
693
694 device_unregister(&devfreq->dev);
695
696 return 0;
697}
698EXPORT_SYMBOL(devfreq_remove_device);
699
700static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
701{
702 struct devfreq **r = res;
703
704 if (WARN_ON(!r || !*r))
705 return 0;
706
707 return *r == data;
708}
709
710static void devm_devfreq_dev_release(struct device *dev, void *res)
711{
712 devfreq_remove_device(*(struct devfreq **)res);
713}
714
715/**
716 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
717 * @dev: the device to add devfreq feature.
718 * @profile: device-specific profile to run devfreq.
719 * @governor_name: name of the policy to choose frequency.
720 * @data: private data for the governor. The devfreq framework does not
721 * touch this value.
722 *
723 * This function manages automatically the memory of devfreq device using device
724 * resource management and simplify the free operation for memory of devfreq
725 * device.
726 */
727struct devfreq *devm_devfreq_add_device(struct device *dev,
728 struct devfreq_dev_profile *profile,
729 const char *governor_name,
730 void *data)
731{
732 struct devfreq **ptr, *devfreq;
733
734 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
735 if (!ptr)
736 return ERR_PTR(-ENOMEM);
737
738 devfreq = devfreq_add_device(dev, profile, governor_name, data);
739 if (IS_ERR(devfreq)) {
740 devres_free(ptr);
741 return devfreq;
742 }
743
744 *ptr = devfreq;
745 devres_add(dev, ptr);
746
747 return devfreq;
748}
749EXPORT_SYMBOL(devm_devfreq_add_device);
750
751#ifdef CONFIG_OF
752/*
753 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
754 * @dev - instance to the given device
755 * @index - index into list of devfreq
756 *
757 * return the instance of devfreq device
758 */
759struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
760{
761 struct device_node *node;
762 struct devfreq *devfreq;
763
764 if (!dev)
765 return ERR_PTR(-EINVAL);
766
767 if (!dev->of_node)
768 return ERR_PTR(-EINVAL);
769
770 node = of_parse_phandle(dev->of_node, "devfreq", index);
771 if (!node)
772 return ERR_PTR(-ENODEV);
773
774 mutex_lock(&devfreq_list_lock);
775 list_for_each_entry(devfreq, &devfreq_list, node) {
776 if (devfreq->dev.parent
777 && devfreq->dev.parent->of_node == node) {
778 mutex_unlock(&devfreq_list_lock);
779 of_node_put(node);
780 return devfreq;
781 }
782 }
783 mutex_unlock(&devfreq_list_lock);
784 of_node_put(node);
785
786 return ERR_PTR(-EPROBE_DEFER);
787}
788#else
789struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
790{
791 return ERR_PTR(-ENODEV);
792}
793#endif /* CONFIG_OF */
794EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
795
796/**
797 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
798 * @dev: the device to add devfreq feature.
799 * @devfreq: the devfreq instance to be removed
800 */
801void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
802{
803 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
804 devm_devfreq_dev_match, devfreq));
805}
806EXPORT_SYMBOL(devm_devfreq_remove_device);
807
808/**
809 * devfreq_suspend_device() - Suspend devfreq of a device.
810 * @devfreq: the devfreq instance to be suspended
811 *
812 * This function is intended to be called by the pm callbacks
813 * (e.g., runtime_suspend, suspend) of the device driver that
814 * holds the devfreq.
815 */
816int devfreq_suspend_device(struct devfreq *devfreq)
817{
818 if (!devfreq)
819 return -EINVAL;
820
821 if (!devfreq->governor)
822 return 0;
823
824 return devfreq->governor->event_handler(devfreq,
825 DEVFREQ_GOV_SUSPEND, NULL);
826}
827EXPORT_SYMBOL(devfreq_suspend_device);
828
829/**
830 * devfreq_resume_device() - Resume devfreq of a device.
831 * @devfreq: the devfreq instance to be resumed
832 *
833 * This function is intended to be called by the pm callbacks
834 * (e.g., runtime_resume, resume) of the device driver that
835 * holds the devfreq.
836 */
837int devfreq_resume_device(struct devfreq *devfreq)
838{
839 if (!devfreq)
840 return -EINVAL;
841
842 if (!devfreq->governor)
843 return 0;
844
845 return devfreq->governor->event_handler(devfreq,
846 DEVFREQ_GOV_RESUME, NULL);
847}
848EXPORT_SYMBOL(devfreq_resume_device);
849
850/**
851 * devfreq_add_governor() - Add devfreq governor
852 * @governor: the devfreq governor to be added
853 */
854int devfreq_add_governor(struct devfreq_governor *governor)
855{
856 struct devfreq_governor *g;
857 struct devfreq *devfreq;
858 int err = 0;
859
860 if (!governor) {
861 pr_err("%s: Invalid parameters.\n", __func__);
862 return -EINVAL;
863 }
864
865 mutex_lock(&devfreq_list_lock);
866 g = find_devfreq_governor(governor->name);
867 if (!IS_ERR(g)) {
868 pr_err("%s: governor %s already registered\n", __func__,
869 g->name);
870 err = -EINVAL;
871 goto err_out;
872 }
873
874 list_add(&governor->node, &devfreq_governor_list);
875
876 list_for_each_entry(devfreq, &devfreq_list, node) {
877 int ret = 0;
878 struct device *dev = devfreq->dev.parent;
879
880 if (!strncmp(devfreq->governor_name, governor->name,
881 DEVFREQ_NAME_LEN)) {
882 /* The following should never occur */
883 if (devfreq->governor) {
884 dev_warn(dev,
885 "%s: Governor %s already present\n",
886 __func__, devfreq->governor->name);
887 ret = devfreq->governor->event_handler(devfreq,
888 DEVFREQ_GOV_STOP, NULL);
889 if (ret) {
890 dev_warn(dev,
891 "%s: Governor %s stop = %d\n",
892 __func__,
893 devfreq->governor->name, ret);
894 }
895 /* Fall through */
896 }
897 devfreq->governor = governor;
898 ret = devfreq->governor->event_handler(devfreq,
899 DEVFREQ_GOV_START, NULL);
900 if (ret) {
901 dev_warn(dev, "%s: Governor %s start=%d\n",
902 __func__, devfreq->governor->name,
903 ret);
904 }
905 }
906 }
907
908err_out:
909 mutex_unlock(&devfreq_list_lock);
910
911 return err;
912}
913EXPORT_SYMBOL(devfreq_add_governor);
914
915/**
916 * devfreq_remove_governor() - Remove devfreq feature from a device.
917 * @governor: the devfreq governor to be removed
918 */
919int devfreq_remove_governor(struct devfreq_governor *governor)
920{
921 struct devfreq_governor *g;
922 struct devfreq *devfreq;
923 int err = 0;
924
925 if (!governor) {
926 pr_err("%s: Invalid parameters.\n", __func__);
927 return -EINVAL;
928 }
929
930 mutex_lock(&devfreq_list_lock);
931 g = find_devfreq_governor(governor->name);
932 if (IS_ERR(g)) {
933 pr_err("%s: governor %s not registered\n", __func__,
934 governor->name);
935 err = PTR_ERR(g);
936 goto err_out;
937 }
938 list_for_each_entry(devfreq, &devfreq_list, node) {
939 int ret;
940 struct device *dev = devfreq->dev.parent;
941
942 if (!strncmp(devfreq->governor_name, governor->name,
943 DEVFREQ_NAME_LEN)) {
944 /* we should have a devfreq governor! */
945 if (!devfreq->governor) {
946 dev_warn(dev, "%s: Governor %s NOT present\n",
947 __func__, governor->name);
948 continue;
949 /* Fall through */
950 }
951 ret = devfreq->governor->event_handler(devfreq,
952 DEVFREQ_GOV_STOP, NULL);
953 if (ret) {
954 dev_warn(dev, "%s: Governor %s stop=%d\n",
955 __func__, devfreq->governor->name,
956 ret);
957 }
958 devfreq->governor = NULL;
959 }
960 }
961
962 list_del(&governor->node);
963err_out:
964 mutex_unlock(&devfreq_list_lock);
965
966 return err;
967}
968EXPORT_SYMBOL(devfreq_remove_governor);
969
970static ssize_t governor_show(struct device *dev,
971 struct device_attribute *attr, char *buf)
972{
973 if (!to_devfreq(dev)->governor)
974 return -EINVAL;
975
976 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
977}
978
979static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
980 const char *buf, size_t count)
981{
982 struct devfreq *df = to_devfreq(dev);
983 int ret;
984 char str_governor[DEVFREQ_NAME_LEN + 1];
985 struct devfreq_governor *governor;
986
987 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
988 if (ret != 1)
989 return -EINVAL;
990
991 mutex_lock(&devfreq_list_lock);
992 governor = find_devfreq_governor(str_governor);
993 if (IS_ERR(governor)) {
994 ret = PTR_ERR(governor);
995 goto out;
996 }
997 if (df->governor == governor) {
998 ret = 0;
999 goto out;
1000 } else if ((df->governor && df->governor->immutable) ||
1001 governor->immutable) {
1002 ret = -EINVAL;
1003 goto out;
1004 }
1005
1006 if (df->governor) {
1007 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1008 if (ret) {
1009 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1010 __func__, df->governor->name, ret);
1011 goto out;
1012 }
1013 }
1014 df->governor = governor;
1015 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
1016 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1017 if (ret)
1018 dev_warn(dev, "%s: Governor %s not started(%d)\n",
1019 __func__, df->governor->name, ret);
1020out:
1021 mutex_unlock(&devfreq_list_lock);
1022
1023 if (!ret)
1024 ret = count;
1025 return ret;
1026}
1027static DEVICE_ATTR_RW(governor);
1028
1029static ssize_t available_governors_show(struct device *d,
1030 struct device_attribute *attr,
1031 char *buf)
1032{
1033 struct devfreq *df = to_devfreq(d);
1034 ssize_t count = 0;
1035
1036 mutex_lock(&devfreq_list_lock);
1037
1038 /*
1039 * The devfreq with immutable governor (e.g., passive) shows
1040 * only own governor.
1041 */
1042 if (df->governor->immutable) {
1043 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1044 "%s ", df->governor_name);
1045 /*
1046 * The devfreq device shows the registered governor except for
1047 * immutable governors such as passive governor .
1048 */
1049 } else {
1050 struct devfreq_governor *governor;
1051
1052 list_for_each_entry(governor, &devfreq_governor_list, node) {
1053 if (governor->immutable)
1054 continue;
1055 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1056 "%s ", governor->name);
1057 }
1058 }
1059
1060 mutex_unlock(&devfreq_list_lock);
1061
1062 /* Truncate the trailing space */
1063 if (count)
1064 count--;
1065
1066 count += sprintf(&buf[count], "\n");
1067
1068 return count;
1069}
1070static DEVICE_ATTR_RO(available_governors);
1071
1072static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1073 char *buf)
1074{
1075 unsigned long freq;
1076 struct devfreq *devfreq = to_devfreq(dev);
1077
1078 if (devfreq->profile->get_cur_freq &&
1079 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1080 return sprintf(buf, "%lu\n", freq);
1081
1082 return sprintf(buf, "%lu\n", devfreq->previous_freq);
1083}
1084static DEVICE_ATTR_RO(cur_freq);
1085
1086static ssize_t target_freq_show(struct device *dev,
1087 struct device_attribute *attr, char *buf)
1088{
1089 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1090}
1091static DEVICE_ATTR_RO(target_freq);
1092
1093static ssize_t polling_interval_show(struct device *dev,
1094 struct device_attribute *attr, char *buf)
1095{
1096 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1097}
1098
1099static ssize_t polling_interval_store(struct device *dev,
1100 struct device_attribute *attr,
1101 const char *buf, size_t count)
1102{
1103 struct devfreq *df = to_devfreq(dev);
1104 unsigned int value;
1105 int ret;
1106
1107 if (!df->governor)
1108 return -EINVAL;
1109
1110 ret = sscanf(buf, "%u", &value);
1111 if (ret != 1)
1112 return -EINVAL;
1113
1114 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1115 ret = count;
1116
1117 return ret;
1118}
1119static DEVICE_ATTR_RW(polling_interval);
1120
1121static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1122 const char *buf, size_t count)
1123{
1124 struct devfreq *df = to_devfreq(dev);
1125 unsigned long value;
1126 int ret;
1127 unsigned long max;
1128
1129 ret = sscanf(buf, "%lu", &value);
1130 if (ret != 1)
1131 return -EINVAL;
1132
1133 mutex_lock(&df->lock);
1134 max = df->max_freq;
1135 if (value && max && value > max) {
1136 ret = -EINVAL;
1137 goto unlock;
1138 }
1139
1140 df->min_freq = value;
1141 update_devfreq(df);
1142 ret = count;
1143unlock:
1144 mutex_unlock(&df->lock);
1145 return ret;
1146}
1147
1148static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1149 char *buf)
1150{
1151 struct devfreq *df = to_devfreq(dev);
1152
1153 return sprintf(buf, "%lu\n", MAX(df->scaling_min_freq, df->min_freq));
1154}
1155
1156static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1157 const char *buf, size_t count)
1158{
1159 struct devfreq *df = to_devfreq(dev);
1160 unsigned long value;
1161 int ret;
1162 unsigned long min;
1163
1164 ret = sscanf(buf, "%lu", &value);
1165 if (ret != 1)
1166 return -EINVAL;
1167
1168 mutex_lock(&df->lock);
1169 min = df->min_freq;
1170 if (value && min && value < min) {
1171 ret = -EINVAL;
1172 goto unlock;
1173 }
1174
1175 df->max_freq = value;
1176 update_devfreq(df);
1177 ret = count;
1178unlock:
1179 mutex_unlock(&df->lock);
1180 return ret;
1181}
1182static DEVICE_ATTR_RW(min_freq);
1183
1184static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1185 char *buf)
1186{
1187 struct devfreq *df = to_devfreq(dev);
1188
1189 return sprintf(buf, "%lu\n", MIN(df->scaling_max_freq, df->max_freq));
1190}
1191static DEVICE_ATTR_RW(max_freq);
1192
1193static ssize_t available_frequencies_show(struct device *d,
1194 struct device_attribute *attr,
1195 char *buf)
1196{
1197 struct devfreq *df = to_devfreq(d);
1198 ssize_t count = 0;
1199 int i;
1200
1201 mutex_lock(&df->lock);
1202
1203 for (i = 0; i < df->profile->max_state; i++)
1204 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1205 "%lu ", df->profile->freq_table[i]);
1206
1207 mutex_unlock(&df->lock);
1208 /* Truncate the trailing space */
1209 if (count)
1210 count--;
1211
1212 count += sprintf(&buf[count], "\n");
1213
1214 return count;
1215}
1216static DEVICE_ATTR_RO(available_frequencies);
1217
1218static ssize_t trans_stat_show(struct device *dev,
1219 struct device_attribute *attr, char *buf)
1220{
1221 struct devfreq *devfreq = to_devfreq(dev);
1222 ssize_t len;
1223 int i, j;
1224 unsigned int max_state = devfreq->profile->max_state;
1225
1226 if (!devfreq->stop_polling &&
1227 devfreq_update_status(devfreq, devfreq->previous_freq))
1228 return 0;
1229 if (max_state == 0)
1230 return sprintf(buf, "Not Supported.\n");
1231
1232 len = sprintf(buf, " From : To\n");
1233 len += sprintf(buf + len, " :");
1234 for (i = 0; i < max_state; i++)
1235 len += sprintf(buf + len, "%10lu",
1236 devfreq->profile->freq_table[i]);
1237
1238 len += sprintf(buf + len, " time(ms)\n");
1239
1240 for (i = 0; i < max_state; i++) {
1241 if (devfreq->profile->freq_table[i]
1242 == devfreq->previous_freq) {
1243 len += sprintf(buf + len, "*");
1244 } else {
1245 len += sprintf(buf + len, " ");
1246 }
1247 len += sprintf(buf + len, "%10lu:",
1248 devfreq->profile->freq_table[i]);
1249 for (j = 0; j < max_state; j++)
1250 len += sprintf(buf + len, "%10u",
1251 devfreq->trans_table[(i * max_state) + j]);
1252 len += sprintf(buf + len, "%10u\n",
1253 jiffies_to_msecs(devfreq->time_in_state[i]));
1254 }
1255
1256 len += sprintf(buf + len, "Total transition : %u\n",
1257 devfreq->total_trans);
1258 return len;
1259}
1260static DEVICE_ATTR_RO(trans_stat);
1261
1262static struct attribute *devfreq_attrs[] = {
1263 &dev_attr_governor.attr,
1264 &dev_attr_available_governors.attr,
1265 &dev_attr_cur_freq.attr,
1266 &dev_attr_available_frequencies.attr,
1267 &dev_attr_target_freq.attr,
1268 &dev_attr_polling_interval.attr,
1269 &dev_attr_min_freq.attr,
1270 &dev_attr_max_freq.attr,
1271 &dev_attr_trans_stat.attr,
1272 NULL,
1273};
1274ATTRIBUTE_GROUPS(devfreq);
1275
1276static int __init devfreq_init(void)
1277{
1278 devfreq_class = class_create(THIS_MODULE, "devfreq");
1279 if (IS_ERR(devfreq_class)) {
1280 pr_err("%s: couldn't create class\n", __FILE__);
1281 return PTR_ERR(devfreq_class);
1282 }
1283
1284 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1285 if (!devfreq_wq) {
1286 class_destroy(devfreq_class);
1287 pr_err("%s: couldn't create workqueue\n", __FILE__);
1288 return -ENOMEM;
1289 }
1290 devfreq_class->dev_groups = devfreq_groups;
1291
1292 return 0;
1293}
1294subsys_initcall(devfreq_init);
1295
1296/*
1297 * The following are helper functions for devfreq user device drivers with
1298 * OPP framework.
1299 */
1300
1301/**
1302 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1303 * freq value given to target callback.
1304 * @dev: The devfreq user device. (parent of devfreq)
1305 * @freq: The frequency given to target function
1306 * @flags: Flags handed from devfreq framework.
1307 *
1308 * The callers are required to call dev_pm_opp_put() for the returned OPP after
1309 * use.
1310 */
1311struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1312 unsigned long *freq,
1313 u32 flags)
1314{
1315 struct dev_pm_opp *opp;
1316
1317 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1318 /* The freq is an upper bound. opp should be lower */
1319 opp = dev_pm_opp_find_freq_floor(dev, freq);
1320
1321 /* If not available, use the closest opp */
1322 if (opp == ERR_PTR(-ERANGE))
1323 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1324 } else {
1325 /* The freq is an lower bound. opp should be higher */
1326 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1327
1328 /* If not available, use the closest opp */
1329 if (opp == ERR_PTR(-ERANGE))
1330 opp = dev_pm_opp_find_freq_floor(dev, freq);
1331 }
1332
1333 return opp;
1334}
1335EXPORT_SYMBOL(devfreq_recommended_opp);
1336
1337/**
1338 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1339 * for any changes in the OPP availability
1340 * changes
1341 * @dev: The devfreq user device. (parent of devfreq)
1342 * @devfreq: The devfreq object.
1343 */
1344int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1345{
1346 return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1347}
1348EXPORT_SYMBOL(devfreq_register_opp_notifier);
1349
1350/**
1351 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1352 * notified for any changes in the OPP
1353 * availability changes anymore.
1354 * @dev: The devfreq user device. (parent of devfreq)
1355 * @devfreq: The devfreq object.
1356 *
1357 * At exit() callback of devfreq_dev_profile, this must be included if
1358 * devfreq_recommended_opp is used.
1359 */
1360int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1361{
1362 return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1363}
1364EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1365
1366static void devm_devfreq_opp_release(struct device *dev, void *res)
1367{
1368 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1369}
1370
1371/**
1372 * devm_ devfreq_register_opp_notifier()
1373 * - Resource-managed devfreq_register_opp_notifier()
1374 * @dev: The devfreq user device. (parent of devfreq)
1375 * @devfreq: The devfreq object.
1376 */
1377int devm_devfreq_register_opp_notifier(struct device *dev,
1378 struct devfreq *devfreq)
1379{
1380 struct devfreq **ptr;
1381 int ret;
1382
1383 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1384 if (!ptr)
1385 return -ENOMEM;
1386
1387 ret = devfreq_register_opp_notifier(dev, devfreq);
1388 if (ret) {
1389 devres_free(ptr);
1390 return ret;
1391 }
1392
1393 *ptr = devfreq;
1394 devres_add(dev, ptr);
1395
1396 return 0;
1397}
1398EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1399
1400/**
1401 * devm_devfreq_unregister_opp_notifier()
1402 * - Resource-managed devfreq_unregister_opp_notifier()
1403 * @dev: The devfreq user device. (parent of devfreq)
1404 * @devfreq: The devfreq object.
1405 */
1406void devm_devfreq_unregister_opp_notifier(struct device *dev,
1407 struct devfreq *devfreq)
1408{
1409 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1410 devm_devfreq_dev_match, devfreq));
1411}
1412EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1413
1414/**
1415 * devfreq_register_notifier() - Register a driver with devfreq
1416 * @devfreq: The devfreq object.
1417 * @nb: The notifier block to register.
1418 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1419 */
1420int devfreq_register_notifier(struct devfreq *devfreq,
1421 struct notifier_block *nb,
1422 unsigned int list)
1423{
1424 int ret = 0;
1425
1426 if (!devfreq)
1427 return -EINVAL;
1428
1429 switch (list) {
1430 case DEVFREQ_TRANSITION_NOTIFIER:
1431 ret = srcu_notifier_chain_register(
1432 &devfreq->transition_notifier_list, nb);
1433 break;
1434 default:
1435 ret = -EINVAL;
1436 }
1437
1438 return ret;
1439}
1440EXPORT_SYMBOL(devfreq_register_notifier);
1441
1442/*
1443 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1444 * @devfreq: The devfreq object.
1445 * @nb: The notifier block to be unregistered.
1446 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1447 */
1448int devfreq_unregister_notifier(struct devfreq *devfreq,
1449 struct notifier_block *nb,
1450 unsigned int list)
1451{
1452 int ret = 0;
1453
1454 if (!devfreq)
1455 return -EINVAL;
1456
1457 switch (list) {
1458 case DEVFREQ_TRANSITION_NOTIFIER:
1459 ret = srcu_notifier_chain_unregister(
1460 &devfreq->transition_notifier_list, nb);
1461 break;
1462 default:
1463 ret = -EINVAL;
1464 }
1465
1466 return ret;
1467}
1468EXPORT_SYMBOL(devfreq_unregister_notifier);
1469
1470struct devfreq_notifier_devres {
1471 struct devfreq *devfreq;
1472 struct notifier_block *nb;
1473 unsigned int list;
1474};
1475
1476static void devm_devfreq_notifier_release(struct device *dev, void *res)
1477{
1478 struct devfreq_notifier_devres *this = res;
1479
1480 devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1481}
1482
1483/**
1484 * devm_devfreq_register_notifier()
1485 - Resource-managed devfreq_register_notifier()
1486 * @dev: The devfreq user device. (parent of devfreq)
1487 * @devfreq: The devfreq object.
1488 * @nb: The notifier block to be unregistered.
1489 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1490 */
1491int devm_devfreq_register_notifier(struct device *dev,
1492 struct devfreq *devfreq,
1493 struct notifier_block *nb,
1494 unsigned int list)
1495{
1496 struct devfreq_notifier_devres *ptr;
1497 int ret;
1498
1499 ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1500 GFP_KERNEL);
1501 if (!ptr)
1502 return -ENOMEM;
1503
1504 ret = devfreq_register_notifier(devfreq, nb, list);
1505 if (ret) {
1506 devres_free(ptr);
1507 return ret;
1508 }
1509
1510 ptr->devfreq = devfreq;
1511 ptr->nb = nb;
1512 ptr->list = list;
1513 devres_add(dev, ptr);
1514
1515 return 0;
1516}
1517EXPORT_SYMBOL(devm_devfreq_register_notifier);
1518
1519/**
1520 * devm_devfreq_unregister_notifier()
1521 - Resource-managed devfreq_unregister_notifier()
1522 * @dev: The devfreq user device. (parent of devfreq)
1523 * @devfreq: The devfreq object.
1524 * @nb: The notifier block to be unregistered.
1525 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1526 */
1527void devm_devfreq_unregister_notifier(struct device *dev,
1528 struct devfreq *devfreq,
1529 struct notifier_block *nb,
1530 unsigned int list)
1531{
1532 WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1533 devm_devfreq_dev_match, devfreq));
1534}
1535EXPORT_SYMBOL(devm_devfreq_unregister_notifier);