2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
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.
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>
31 static struct class *devfreq_class;
34 * devfreq core provides delayed work based load monitoring helper
35 * functions. Governors can use these or can implement their own
36 * monitoring mechanism.
38 static struct workqueue_struct *devfreq_wq;
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);
47 * find_device_devfreq() - find devfreq struct using device pointer
48 * @dev: device pointer used to lookup device devfreq.
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.
53 static struct devfreq *find_device_devfreq(struct device *dev)
55 struct devfreq *tmp_devfreq;
57 if (IS_ERR_OR_NULL(dev)) {
58 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
59 return ERR_PTR(-EINVAL);
61 WARN(!mutex_is_locked(&devfreq_list_lock),
62 "devfreq_list_lock must be locked.");
64 list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
65 if (tmp_devfreq->dev.parent == dev)
69 return ERR_PTR(-ENODEV);
73 * devfreq_get_freq_level() - Lookup freq_table for the frequency
74 * @devfreq: the devfreq instance
75 * @freq: the target frequency
77 static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
81 for (lev = 0; lev < devfreq->profile->max_state; lev++)
82 if (freq == devfreq->profile->freq_table[lev])
89 * devfreq_set_freq_table() - Initialize freq_table for the frequency
90 * @devfreq: the devfreq instance
92 static void devfreq_set_freq_table(struct devfreq *devfreq)
94 struct devfreq_dev_profile *profile = devfreq->profile;
95 struct dev_pm_opp *opp;
99 /* Initialize the freq_table from OPP table */
100 count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
104 profile->max_state = count;
105 profile->freq_table = devm_kcalloc(devfreq->dev.parent,
107 sizeof(*profile->freq_table),
109 if (!profile->freq_table) {
110 profile->max_state = 0;
115 for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
116 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
118 devm_kfree(devfreq->dev.parent, profile->freq_table);
119 profile->max_state = 0;
123 profile->freq_table[i] = freq;
129 * devfreq_update_status() - Update statistics of devfreq behavior
130 * @devfreq: the devfreq instance
131 * @freq: the update target frequency
133 static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
135 int lev, prev_lev, ret = 0;
136 unsigned long cur_time;
140 prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
146 devfreq->time_in_state[prev_lev] +=
147 cur_time - devfreq->last_stat_updated;
149 lev = devfreq_get_freq_level(devfreq, freq);
155 if (lev != prev_lev) {
156 devfreq->trans_table[(prev_lev *
157 devfreq->profile->max_state) + lev]++;
158 devfreq->total_trans++;
162 devfreq->last_stat_updated = cur_time;
167 * find_devfreq_governor() - find devfreq governor from name
168 * @name: name of the governor
170 * Search the list of devfreq governors and return the matched
171 * governor's pointer. devfreq_list_lock should be held by the caller.
173 static struct devfreq_governor *find_devfreq_governor(const char *name)
175 struct devfreq_governor *tmp_governor;
177 if (IS_ERR_OR_NULL(name)) {
178 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
179 return ERR_PTR(-EINVAL);
181 WARN(!mutex_is_locked(&devfreq_list_lock),
182 "devfreq_list_lock must be locked.");
184 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
185 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
189 return ERR_PTR(-ENODEV);
192 static int devfreq_notify_transition(struct devfreq *devfreq,
193 struct devfreq_freqs *freqs, unsigned int state)
199 case DEVFREQ_PRECHANGE:
200 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
201 DEVFREQ_PRECHANGE, freqs);
204 case DEVFREQ_POSTCHANGE:
205 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
206 DEVFREQ_POSTCHANGE, freqs);
215 /* Load monitoring helper functions for governors use */
218 * update_devfreq() - Reevaluate the device and configure frequency.
219 * @devfreq: the devfreq instance.
221 * Note: Lock devfreq->lock before calling update_devfreq
222 * This function is exported for governors.
224 int update_devfreq(struct devfreq *devfreq)
226 struct devfreq_freqs freqs;
227 unsigned long freq, cur_freq;
231 if (!mutex_is_locked(&devfreq->lock)) {
232 WARN(true, "devfreq->lock must be locked by the caller.\n");
236 if (!devfreq->governor)
239 /* Reevaluate the proper frequency */
240 err = devfreq->governor->get_target_freq(devfreq, &freq);
245 * Adjust the frequency with user freq and QoS.
247 * List from the highest priority
252 if (devfreq->min_freq && freq < devfreq->min_freq) {
253 freq = devfreq->min_freq;
254 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
256 if (devfreq->max_freq && freq > devfreq->max_freq) {
257 freq = devfreq->max_freq;
258 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
261 if (devfreq->profile->get_cur_freq)
262 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
264 cur_freq = devfreq->previous_freq;
266 freqs.old = cur_freq;
268 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
270 err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
272 freqs.new = cur_freq;
273 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
278 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
280 if (devfreq->profile->freq_table)
281 if (devfreq_update_status(devfreq, freq))
282 dev_err(&devfreq->dev,
283 "Couldn't update frequency transition information.\n");
285 devfreq->previous_freq = freq;
288 EXPORT_SYMBOL(update_devfreq);
291 * devfreq_monitor() - Periodically poll devfreq objects.
292 * @work: the work struct used to run devfreq_monitor periodically.
295 static void devfreq_monitor(struct work_struct *work)
298 struct devfreq *devfreq = container_of(work,
299 struct devfreq, work.work);
301 mutex_lock(&devfreq->lock);
302 err = update_devfreq(devfreq);
304 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
306 queue_delayed_work(devfreq_wq, &devfreq->work,
307 msecs_to_jiffies(devfreq->profile->polling_ms));
308 mutex_unlock(&devfreq->lock);
312 * devfreq_monitor_start() - Start load monitoring of devfreq instance
313 * @devfreq: the devfreq instance.
315 * Helper function for starting devfreq device load monitoing. By
316 * default delayed work based monitoring is supported. Function
317 * to be called from governor in response to DEVFREQ_GOV_START
318 * event when device is added to devfreq framework.
320 void devfreq_monitor_start(struct devfreq *devfreq)
322 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
323 if (devfreq->profile->polling_ms)
324 queue_delayed_work(devfreq_wq, &devfreq->work,
325 msecs_to_jiffies(devfreq->profile->polling_ms));
327 EXPORT_SYMBOL(devfreq_monitor_start);
330 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
331 * @devfreq: the devfreq instance.
333 * Helper function to stop devfreq device load monitoing. Function
334 * to be called from governor in response to DEVFREQ_GOV_STOP
335 * event when device is removed from devfreq framework.
337 void devfreq_monitor_stop(struct devfreq *devfreq)
339 cancel_delayed_work_sync(&devfreq->work);
341 EXPORT_SYMBOL(devfreq_monitor_stop);
344 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
345 * @devfreq: the devfreq instance.
347 * Helper function to suspend devfreq device load monitoing. Function
348 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
349 * event or when polling interval is set to zero.
351 * Note: Though this function is same as devfreq_monitor_stop(),
352 * intentionally kept separate to provide hooks for collecting
353 * transition statistics.
355 void devfreq_monitor_suspend(struct devfreq *devfreq)
357 mutex_lock(&devfreq->lock);
358 if (devfreq->stop_polling) {
359 mutex_unlock(&devfreq->lock);
363 devfreq_update_status(devfreq, devfreq->previous_freq);
364 devfreq->stop_polling = true;
365 mutex_unlock(&devfreq->lock);
366 cancel_delayed_work_sync(&devfreq->work);
368 EXPORT_SYMBOL(devfreq_monitor_suspend);
371 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
372 * @devfreq: the devfreq instance.
374 * Helper function to resume devfreq device load monitoing. Function
375 * to be called from governor in response to DEVFREQ_GOV_RESUME
376 * event or when polling interval is set to non-zero.
378 void devfreq_monitor_resume(struct devfreq *devfreq)
382 mutex_lock(&devfreq->lock);
383 if (!devfreq->stop_polling)
386 if (!delayed_work_pending(&devfreq->work) &&
387 devfreq->profile->polling_ms)
388 queue_delayed_work(devfreq_wq, &devfreq->work,
389 msecs_to_jiffies(devfreq->profile->polling_ms));
391 devfreq->last_stat_updated = jiffies;
392 devfreq->stop_polling = false;
394 if (devfreq->profile->get_cur_freq &&
395 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
396 devfreq->previous_freq = freq;
399 mutex_unlock(&devfreq->lock);
401 EXPORT_SYMBOL(devfreq_monitor_resume);
404 * devfreq_interval_update() - Update device devfreq monitoring interval
405 * @devfreq: the devfreq instance.
406 * @delay: new polling interval to be set.
408 * Helper function to set new load monitoring polling interval. Function
409 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
411 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
413 unsigned int cur_delay = devfreq->profile->polling_ms;
414 unsigned int new_delay = *delay;
416 mutex_lock(&devfreq->lock);
417 devfreq->profile->polling_ms = new_delay;
419 if (devfreq->stop_polling)
422 /* if new delay is zero, stop polling */
424 mutex_unlock(&devfreq->lock);
425 cancel_delayed_work_sync(&devfreq->work);
429 /* if current delay is zero, start polling with new delay */
431 queue_delayed_work(devfreq_wq, &devfreq->work,
432 msecs_to_jiffies(devfreq->profile->polling_ms));
436 /* if current delay is greater than new delay, restart polling */
437 if (cur_delay > new_delay) {
438 mutex_unlock(&devfreq->lock);
439 cancel_delayed_work_sync(&devfreq->work);
440 mutex_lock(&devfreq->lock);
441 if (!devfreq->stop_polling)
442 queue_delayed_work(devfreq_wq, &devfreq->work,
443 msecs_to_jiffies(devfreq->profile->polling_ms));
446 mutex_unlock(&devfreq->lock);
448 EXPORT_SYMBOL(devfreq_interval_update);
451 * devfreq_notifier_call() - Notify that the device frequency requirements
452 * has been changed out of devfreq framework.
453 * @nb: the notifier_block (supposed to be devfreq->nb)
457 * Called by a notifier that uses devfreq->nb.
459 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
462 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
465 mutex_lock(&devfreq->lock);
466 ret = update_devfreq(devfreq);
467 mutex_unlock(&devfreq->lock);
473 * _remove_devfreq() - Remove devfreq from the list and release its resources.
474 * @devfreq: the devfreq struct
476 static void _remove_devfreq(struct devfreq *devfreq)
478 mutex_lock(&devfreq_list_lock);
479 if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
480 mutex_unlock(&devfreq_list_lock);
481 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
484 list_del(&devfreq->node);
485 mutex_unlock(&devfreq_list_lock);
487 if (devfreq->governor)
488 devfreq->governor->event_handler(devfreq,
489 DEVFREQ_GOV_STOP, NULL);
491 if (devfreq->profile->exit)
492 devfreq->profile->exit(devfreq->dev.parent);
494 mutex_destroy(&devfreq->lock);
499 * devfreq_dev_release() - Callback for struct device to release the device.
500 * @dev: the devfreq device
502 * This calls _remove_devfreq() if _remove_devfreq() is not called.
504 static void devfreq_dev_release(struct device *dev)
506 struct devfreq *devfreq = to_devfreq(dev);
508 _remove_devfreq(devfreq);
512 * devfreq_add_device() - Add devfreq feature to the device
513 * @dev: the device to add devfreq feature.
514 * @profile: device-specific profile to run devfreq.
515 * @governor_name: name of the policy to choose frequency.
516 * @data: private data for the governor. The devfreq framework does not
519 struct devfreq *devfreq_add_device(struct device *dev,
520 struct devfreq_dev_profile *profile,
521 const char *governor_name,
524 struct devfreq *devfreq;
525 struct devfreq_governor *governor;
528 if (!dev || !profile || !governor_name) {
529 dev_err(dev, "%s: Invalid parameters.\n", __func__);
530 return ERR_PTR(-EINVAL);
533 mutex_lock(&devfreq_list_lock);
534 devfreq = find_device_devfreq(dev);
535 mutex_unlock(&devfreq_list_lock);
536 if (!IS_ERR(devfreq)) {
537 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
542 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
544 dev_err(dev, "%s: Unable to create devfreq for the device\n",
550 mutex_init(&devfreq->lock);
551 mutex_lock(&devfreq->lock);
552 devfreq->dev.parent = dev;
553 devfreq->dev.class = devfreq_class;
554 devfreq->dev.release = devfreq_dev_release;
555 devfreq->profile = profile;
556 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
557 devfreq->previous_freq = profile->initial_freq;
558 devfreq->last_status.current_frequency = profile->initial_freq;
559 devfreq->data = data;
560 devfreq->nb.notifier_call = devfreq_notifier_call;
562 if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
563 mutex_unlock(&devfreq->lock);
564 devfreq_set_freq_table(devfreq);
565 mutex_lock(&devfreq->lock);
568 dev_set_name(&devfreq->dev, "%s", dev_name(dev));
569 err = device_register(&devfreq->dev);
571 mutex_unlock(&devfreq->lock);
575 devfreq->trans_table = devm_kzalloc(&devfreq->dev, sizeof(unsigned int) *
576 devfreq->profile->max_state *
577 devfreq->profile->max_state,
579 devfreq->time_in_state = devm_kzalloc(&devfreq->dev, sizeof(unsigned long) *
580 devfreq->profile->max_state,
582 devfreq->last_stat_updated = jiffies;
584 srcu_init_notifier_head(&devfreq->transition_notifier_list);
586 mutex_unlock(&devfreq->lock);
588 mutex_lock(&devfreq_list_lock);
589 list_add(&devfreq->node, &devfreq_list);
591 governor = find_devfreq_governor(devfreq->governor_name);
592 if (!IS_ERR(governor))
593 devfreq->governor = governor;
594 if (devfreq->governor)
595 err = devfreq->governor->event_handler(devfreq,
596 DEVFREQ_GOV_START, NULL);
597 mutex_unlock(&devfreq_list_lock);
599 dev_err(dev, "%s: Unable to start governor for the device\n",
607 list_del(&devfreq->node);
608 device_unregister(&devfreq->dev);
612 EXPORT_SYMBOL(devfreq_add_device);
615 * devfreq_remove_device() - Remove devfreq feature from a device.
616 * @devfreq: the devfreq instance to be removed
618 * The opposite of devfreq_add_device().
620 int devfreq_remove_device(struct devfreq *devfreq)
625 device_unregister(&devfreq->dev);
629 EXPORT_SYMBOL(devfreq_remove_device);
631 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
633 struct devfreq **r = res;
635 if (WARN_ON(!r || !*r))
641 static void devm_devfreq_dev_release(struct device *dev, void *res)
643 devfreq_remove_device(*(struct devfreq **)res);
647 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
648 * @dev: the device to add devfreq feature.
649 * @profile: device-specific profile to run devfreq.
650 * @governor_name: name of the policy to choose frequency.
651 * @data: private data for the governor. The devfreq framework does not
654 * This function manages automatically the memory of devfreq device using device
655 * resource management and simplify the free operation for memory of devfreq
658 struct devfreq *devm_devfreq_add_device(struct device *dev,
659 struct devfreq_dev_profile *profile,
660 const char *governor_name,
663 struct devfreq **ptr, *devfreq;
665 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
667 return ERR_PTR(-ENOMEM);
669 devfreq = devfreq_add_device(dev, profile, governor_name, data);
670 if (IS_ERR(devfreq)) {
672 return ERR_PTR(-ENOMEM);
676 devres_add(dev, ptr);
680 EXPORT_SYMBOL(devm_devfreq_add_device);
684 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
685 * @dev - instance to the given device
686 * @index - index into list of devfreq
688 * return the instance of devfreq device
690 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
692 struct device_node *node;
693 struct devfreq *devfreq;
696 return ERR_PTR(-EINVAL);
699 return ERR_PTR(-EINVAL);
701 node = of_parse_phandle(dev->of_node, "devfreq", index);
703 return ERR_PTR(-ENODEV);
705 mutex_lock(&devfreq_list_lock);
706 list_for_each_entry(devfreq, &devfreq_list, node) {
707 if (devfreq->dev.parent
708 && devfreq->dev.parent->of_node == node) {
709 mutex_unlock(&devfreq_list_lock);
713 mutex_unlock(&devfreq_list_lock);
715 return ERR_PTR(-EPROBE_DEFER);
718 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
720 return ERR_PTR(-ENODEV);
722 #endif /* CONFIG_OF */
723 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
726 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
727 * @dev: the device to add devfreq feature.
728 * @devfreq: the devfreq instance to be removed
730 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
732 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
733 devm_devfreq_dev_match, devfreq));
735 EXPORT_SYMBOL(devm_devfreq_remove_device);
738 * devfreq_suspend_device() - Suspend devfreq of a device.
739 * @devfreq: the devfreq instance to be suspended
741 * This function is intended to be called by the pm callbacks
742 * (e.g., runtime_suspend, suspend) of the device driver that
745 int devfreq_suspend_device(struct devfreq *devfreq)
750 if (!devfreq->governor)
753 return devfreq->governor->event_handler(devfreq,
754 DEVFREQ_GOV_SUSPEND, NULL);
756 EXPORT_SYMBOL(devfreq_suspend_device);
759 * devfreq_resume_device() - Resume devfreq of a device.
760 * @devfreq: the devfreq instance to be resumed
762 * This function is intended to be called by the pm callbacks
763 * (e.g., runtime_resume, resume) of the device driver that
766 int devfreq_resume_device(struct devfreq *devfreq)
771 if (!devfreq->governor)
774 return devfreq->governor->event_handler(devfreq,
775 DEVFREQ_GOV_RESUME, NULL);
777 EXPORT_SYMBOL(devfreq_resume_device);
780 * devfreq_add_governor() - Add devfreq governor
781 * @governor: the devfreq governor to be added
783 int devfreq_add_governor(struct devfreq_governor *governor)
785 struct devfreq_governor *g;
786 struct devfreq *devfreq;
790 pr_err("%s: Invalid parameters.\n", __func__);
794 mutex_lock(&devfreq_list_lock);
795 g = find_devfreq_governor(governor->name);
797 pr_err("%s: governor %s already registered\n", __func__,
803 list_add(&governor->node, &devfreq_governor_list);
805 list_for_each_entry(devfreq, &devfreq_list, node) {
807 struct device *dev = devfreq->dev.parent;
809 if (!strncmp(devfreq->governor_name, governor->name,
811 /* The following should never occur */
812 if (devfreq->governor) {
814 "%s: Governor %s already present\n",
815 __func__, devfreq->governor->name);
816 ret = devfreq->governor->event_handler(devfreq,
817 DEVFREQ_GOV_STOP, NULL);
820 "%s: Governor %s stop = %d\n",
822 devfreq->governor->name, ret);
826 devfreq->governor = governor;
827 ret = devfreq->governor->event_handler(devfreq,
828 DEVFREQ_GOV_START, NULL);
830 dev_warn(dev, "%s: Governor %s start=%d\n",
831 __func__, devfreq->governor->name,
838 mutex_unlock(&devfreq_list_lock);
842 EXPORT_SYMBOL(devfreq_add_governor);
845 * devfreq_remove_device() - Remove devfreq feature from a device.
846 * @governor: the devfreq governor to be removed
848 int devfreq_remove_governor(struct devfreq_governor *governor)
850 struct devfreq_governor *g;
851 struct devfreq *devfreq;
855 pr_err("%s: Invalid parameters.\n", __func__);
859 mutex_lock(&devfreq_list_lock);
860 g = find_devfreq_governor(governor->name);
862 pr_err("%s: governor %s not registered\n", __func__,
867 list_for_each_entry(devfreq, &devfreq_list, node) {
869 struct device *dev = devfreq->dev.parent;
871 if (!strncmp(devfreq->governor_name, governor->name,
873 /* we should have a devfreq governor! */
874 if (!devfreq->governor) {
875 dev_warn(dev, "%s: Governor %s NOT present\n",
876 __func__, governor->name);
880 ret = devfreq->governor->event_handler(devfreq,
881 DEVFREQ_GOV_STOP, NULL);
883 dev_warn(dev, "%s: Governor %s stop=%d\n",
884 __func__, devfreq->governor->name,
887 devfreq->governor = NULL;
891 list_del(&governor->node);
893 mutex_unlock(&devfreq_list_lock);
897 EXPORT_SYMBOL(devfreq_remove_governor);
899 static ssize_t governor_show(struct device *dev,
900 struct device_attribute *attr, char *buf)
902 if (!to_devfreq(dev)->governor)
905 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
908 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
909 const char *buf, size_t count)
911 struct devfreq *df = to_devfreq(dev);
913 char str_governor[DEVFREQ_NAME_LEN + 1];
914 struct devfreq_governor *governor;
916 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
920 mutex_lock(&devfreq_list_lock);
921 governor = find_devfreq_governor(str_governor);
922 if (IS_ERR(governor)) {
923 ret = PTR_ERR(governor);
926 if (df->governor == governor) {
932 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
934 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
935 __func__, df->governor->name, ret);
939 df->governor = governor;
940 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
941 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
943 dev_warn(dev, "%s: Governor %s not started(%d)\n",
944 __func__, df->governor->name, ret);
946 mutex_unlock(&devfreq_list_lock);
952 static DEVICE_ATTR_RW(governor);
954 static ssize_t available_governors_show(struct device *d,
955 struct device_attribute *attr,
958 struct devfreq_governor *tmp_governor;
961 mutex_lock(&devfreq_list_lock);
962 list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
963 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
964 "%s ", tmp_governor->name);
965 mutex_unlock(&devfreq_list_lock);
967 /* Truncate the trailing space */
971 count += sprintf(&buf[count], "\n");
975 static DEVICE_ATTR_RO(available_governors);
977 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
981 struct devfreq *devfreq = to_devfreq(dev);
983 if (devfreq->profile->get_cur_freq &&
984 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
985 return sprintf(buf, "%lu\n", freq);
987 return sprintf(buf, "%lu\n", devfreq->previous_freq);
989 static DEVICE_ATTR_RO(cur_freq);
991 static ssize_t target_freq_show(struct device *dev,
992 struct device_attribute *attr, char *buf)
994 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
996 static DEVICE_ATTR_RO(target_freq);
998 static ssize_t polling_interval_show(struct device *dev,
999 struct device_attribute *attr, char *buf)
1001 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1004 static ssize_t polling_interval_store(struct device *dev,
1005 struct device_attribute *attr,
1006 const char *buf, size_t count)
1008 struct devfreq *df = to_devfreq(dev);
1015 ret = sscanf(buf, "%u", &value);
1019 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1024 static DEVICE_ATTR_RW(polling_interval);
1026 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1027 const char *buf, size_t count)
1029 struct devfreq *df = to_devfreq(dev);
1030 unsigned long value;
1034 ret = sscanf(buf, "%lu", &value);
1038 mutex_lock(&df->lock);
1040 if (value && max && value > max) {
1045 df->min_freq = value;
1049 mutex_unlock(&df->lock);
1053 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1054 const char *buf, size_t count)
1056 struct devfreq *df = to_devfreq(dev);
1057 unsigned long value;
1061 ret = sscanf(buf, "%lu", &value);
1065 mutex_lock(&df->lock);
1067 if (value && min && value < min) {
1072 df->max_freq = value;
1076 mutex_unlock(&df->lock);
1080 #define show_one(name) \
1081 static ssize_t name##_show \
1082 (struct device *dev, struct device_attribute *attr, char *buf) \
1084 return sprintf(buf, "%lu\n", to_devfreq(dev)->name); \
1089 static DEVICE_ATTR_RW(min_freq);
1090 static DEVICE_ATTR_RW(max_freq);
1092 static ssize_t available_frequencies_show(struct device *d,
1093 struct device_attribute *attr,
1096 struct devfreq *df = to_devfreq(d);
1097 struct device *dev = df->dev.parent;
1098 struct dev_pm_opp *opp;
1100 unsigned long freq = 0;
1104 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1108 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1114 /* Truncate the trailing space */
1118 count += sprintf(&buf[count], "\n");
1122 static DEVICE_ATTR_RO(available_frequencies);
1124 static ssize_t trans_stat_show(struct device *dev,
1125 struct device_attribute *attr, char *buf)
1127 struct devfreq *devfreq = to_devfreq(dev);
1130 unsigned int max_state = devfreq->profile->max_state;
1132 if (!devfreq->stop_polling &&
1133 devfreq_update_status(devfreq, devfreq->previous_freq))
1136 return sprintf(buf, "Not Supported.\n");
1138 len = sprintf(buf, " From : To\n");
1139 len += sprintf(buf + len, " :");
1140 for (i = 0; i < max_state; i++)
1141 len += sprintf(buf + len, "%10lu",
1142 devfreq->profile->freq_table[i]);
1144 len += sprintf(buf + len, " time(ms)\n");
1146 for (i = 0; i < max_state; i++) {
1147 if (devfreq->profile->freq_table[i]
1148 == devfreq->previous_freq) {
1149 len += sprintf(buf + len, "*");
1151 len += sprintf(buf + len, " ");
1153 len += sprintf(buf + len, "%10lu:",
1154 devfreq->profile->freq_table[i]);
1155 for (j = 0; j < max_state; j++)
1156 len += sprintf(buf + len, "%10u",
1157 devfreq->trans_table[(i * max_state) + j]);
1158 len += sprintf(buf + len, "%10u\n",
1159 jiffies_to_msecs(devfreq->time_in_state[i]));
1162 len += sprintf(buf + len, "Total transition : %u\n",
1163 devfreq->total_trans);
1166 static DEVICE_ATTR_RO(trans_stat);
1168 static struct attribute *devfreq_attrs[] = {
1169 &dev_attr_governor.attr,
1170 &dev_attr_available_governors.attr,
1171 &dev_attr_cur_freq.attr,
1172 &dev_attr_available_frequencies.attr,
1173 &dev_attr_target_freq.attr,
1174 &dev_attr_polling_interval.attr,
1175 &dev_attr_min_freq.attr,
1176 &dev_attr_max_freq.attr,
1177 &dev_attr_trans_stat.attr,
1180 ATTRIBUTE_GROUPS(devfreq);
1182 static int __init devfreq_init(void)
1184 devfreq_class = class_create(THIS_MODULE, "devfreq");
1185 if (IS_ERR(devfreq_class)) {
1186 pr_err("%s: couldn't create class\n", __FILE__);
1187 return PTR_ERR(devfreq_class);
1190 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1192 class_destroy(devfreq_class);
1193 pr_err("%s: couldn't create workqueue\n", __FILE__);
1196 devfreq_class->dev_groups = devfreq_groups;
1200 subsys_initcall(devfreq_init);
1202 static void __exit devfreq_exit(void)
1204 class_destroy(devfreq_class);
1205 destroy_workqueue(devfreq_wq);
1207 module_exit(devfreq_exit);
1210 * The followings are helper functions for devfreq user device drivers with
1215 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1216 * freq value given to target callback.
1217 * @dev: The devfreq user device. (parent of devfreq)
1218 * @freq: The frequency given to target function
1219 * @flags: Flags handed from devfreq framework.
1221 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1222 * protected pointer. The reason for the same is that the opp pointer which is
1223 * returned will remain valid for use with opp_get_{voltage, freq} only while
1224 * under the locked area. The pointer returned must be used prior to unlocking
1225 * with rcu_read_unlock() to maintain the integrity of the pointer.
1227 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1228 unsigned long *freq,
1231 struct dev_pm_opp *opp;
1233 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1234 /* The freq is an upper bound. opp should be lower */
1235 opp = dev_pm_opp_find_freq_floor(dev, freq);
1237 /* If not available, use the closest opp */
1238 if (opp == ERR_PTR(-ERANGE))
1239 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1241 /* The freq is an lower bound. opp should be higher */
1242 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1244 /* If not available, use the closest opp */
1245 if (opp == ERR_PTR(-ERANGE))
1246 opp = dev_pm_opp_find_freq_floor(dev, freq);
1251 EXPORT_SYMBOL(devfreq_recommended_opp);
1254 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1255 * for any changes in the OPP availability
1257 * @dev: The devfreq user device. (parent of devfreq)
1258 * @devfreq: The devfreq object.
1260 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1262 struct srcu_notifier_head *nh;
1266 nh = dev_pm_opp_get_notifier(dev);
1271 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1275 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1278 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1279 * notified for any changes in the OPP
1280 * availability changes anymore.
1281 * @dev: The devfreq user device. (parent of devfreq)
1282 * @devfreq: The devfreq object.
1284 * At exit() callback of devfreq_dev_profile, this must be included if
1285 * devfreq_recommended_opp is used.
1287 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1289 struct srcu_notifier_head *nh;
1293 nh = dev_pm_opp_get_notifier(dev);
1298 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1302 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1304 static void devm_devfreq_opp_release(struct device *dev, void *res)
1306 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1310 * devm_ devfreq_register_opp_notifier()
1311 * - Resource-managed devfreq_register_opp_notifier()
1312 * @dev: The devfreq user device. (parent of devfreq)
1313 * @devfreq: The devfreq object.
1315 int devm_devfreq_register_opp_notifier(struct device *dev,
1316 struct devfreq *devfreq)
1318 struct devfreq **ptr;
1321 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1325 ret = devfreq_register_opp_notifier(dev, devfreq);
1332 devres_add(dev, ptr);
1336 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1339 * devm_devfreq_unregister_opp_notifier()
1340 * - Resource-managed devfreq_unregister_opp_notifier()
1341 * @dev: The devfreq user device. (parent of devfreq)
1342 * @devfreq: The devfreq object.
1344 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1345 struct devfreq *devfreq)
1347 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1348 devm_devfreq_dev_match, devfreq));
1350 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1353 * devfreq_register_notifier() - Register a driver with devfreq
1354 * @devfreq: The devfreq object.
1355 * @nb: The notifier block to register.
1356 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1358 int devfreq_register_notifier(struct devfreq *devfreq,
1359 struct notifier_block *nb,
1368 case DEVFREQ_TRANSITION_NOTIFIER:
1369 ret = srcu_notifier_chain_register(
1370 &devfreq->transition_notifier_list, nb);
1378 EXPORT_SYMBOL(devfreq_register_notifier);
1381 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1382 * @devfreq: The devfreq object.
1383 * @nb: The notifier block to be unregistered.
1384 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1386 int devfreq_unregister_notifier(struct devfreq *devfreq,
1387 struct notifier_block *nb,
1396 case DEVFREQ_TRANSITION_NOTIFIER:
1397 ret = srcu_notifier_chain_unregister(
1398 &devfreq->transition_notifier_list, nb);
1406 EXPORT_SYMBOL(devfreq_unregister_notifier);
1408 struct devfreq_notifier_devres {
1409 struct devfreq *devfreq;
1410 struct notifier_block *nb;
1414 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1416 struct devfreq_notifier_devres *this = res;
1418 devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1422 * devm_devfreq_register_notifier()
1423 - Resource-managed devfreq_register_notifier()
1424 * @dev: The devfreq user device. (parent of devfreq)
1425 * @devfreq: The devfreq object.
1426 * @nb: The notifier block to be unregistered.
1427 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1429 int devm_devfreq_register_notifier(struct device *dev,
1430 struct devfreq *devfreq,
1431 struct notifier_block *nb,
1434 struct devfreq_notifier_devres *ptr;
1437 ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1442 ret = devfreq_register_notifier(devfreq, nb, list);
1448 ptr->devfreq = devfreq;
1451 devres_add(dev, ptr);
1455 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1458 * devm_devfreq_unregister_notifier()
1459 - Resource-managed devfreq_unregister_notifier()
1460 * @dev: The devfreq user device. (parent of devfreq)
1461 * @devfreq: The devfreq object.
1462 * @nb: The notifier block to be unregistered.
1463 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1465 void devm_devfreq_unregister_notifier(struct device *dev,
1466 struct devfreq *devfreq,
1467 struct notifier_block *nb,
1470 WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1471 devm_devfreq_dev_match, devfreq));
1473 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);
1475 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1476 MODULE_DESCRIPTION("devfreq class support");
1477 MODULE_LICENSE("GPL");