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/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>
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;
114 for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
115 opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
117 devm_kfree(devfreq->dev.parent, profile->freq_table);
118 profile->max_state = 0;
122 profile->freq_table[i] = freq;
127 * devfreq_update_status() - Update statistics of devfreq behavior
128 * @devfreq: the devfreq instance
129 * @freq: the update target frequency
131 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
133 int lev, prev_lev, ret = 0;
134 unsigned long cur_time;
136 lockdep_assert_held(&devfreq->lock);
139 /* Immediately exit if previous_freq is not initialized yet. */
140 if (!devfreq->previous_freq)
143 prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
149 devfreq->time_in_state[prev_lev] +=
150 cur_time - devfreq->last_stat_updated;
152 lev = devfreq_get_freq_level(devfreq, freq);
158 if (lev != prev_lev) {
159 devfreq->trans_table[(prev_lev *
160 devfreq->profile->max_state) + lev]++;
161 devfreq->total_trans++;
165 devfreq->last_stat_updated = cur_time;
168 EXPORT_SYMBOL(devfreq_update_status);
171 * find_devfreq_governor() - find devfreq governor from name
172 * @name: name of the governor
174 * Search the list of devfreq governors and return the matched
175 * governor's pointer. devfreq_list_lock should be held by the caller.
177 static struct devfreq_governor *find_devfreq_governor(const char *name)
179 struct devfreq_governor *tmp_governor;
181 if (IS_ERR_OR_NULL(name)) {
182 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
183 return ERR_PTR(-EINVAL);
185 WARN(!mutex_is_locked(&devfreq_list_lock),
186 "devfreq_list_lock must be locked.");
188 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
189 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
193 return ERR_PTR(-ENODEV);
196 static int devfreq_notify_transition(struct devfreq *devfreq,
197 struct devfreq_freqs *freqs, unsigned int state)
203 case DEVFREQ_PRECHANGE:
204 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
205 DEVFREQ_PRECHANGE, freqs);
208 case DEVFREQ_POSTCHANGE:
209 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
210 DEVFREQ_POSTCHANGE, freqs);
219 /* Load monitoring helper functions for governors use */
222 * update_devfreq() - Reevaluate the device and configure frequency.
223 * @devfreq: the devfreq instance.
225 * Note: Lock devfreq->lock before calling update_devfreq
226 * This function is exported for governors.
228 int update_devfreq(struct devfreq *devfreq)
230 struct devfreq_freqs freqs;
231 unsigned long freq, cur_freq;
235 if (!mutex_is_locked(&devfreq->lock)) {
236 WARN(true, "devfreq->lock must be locked by the caller.\n");
240 if (!devfreq->governor)
243 /* Reevaluate the proper frequency */
244 err = devfreq->governor->get_target_freq(devfreq, &freq);
249 * Adjust the frequency with user freq and QoS.
251 * List from the highest priority
256 if (devfreq->min_freq && freq < devfreq->min_freq) {
257 freq = devfreq->min_freq;
258 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
260 if (devfreq->max_freq && freq > devfreq->max_freq) {
261 freq = devfreq->max_freq;
262 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
265 if (devfreq->profile->get_cur_freq)
266 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
268 cur_freq = devfreq->previous_freq;
270 freqs.old = cur_freq;
272 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
274 err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
276 freqs.new = cur_freq;
277 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
282 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
284 if (devfreq->profile->freq_table)
285 if (devfreq_update_status(devfreq, freq))
286 dev_err(&devfreq->dev,
287 "Couldn't update frequency transition information.\n");
289 devfreq->previous_freq = freq;
292 EXPORT_SYMBOL(update_devfreq);
295 * devfreq_monitor() - Periodically poll devfreq objects.
296 * @work: the work struct used to run devfreq_monitor periodically.
299 static void devfreq_monitor(struct work_struct *work)
302 struct devfreq *devfreq = container_of(work,
303 struct devfreq, work.work);
305 mutex_lock(&devfreq->lock);
306 err = update_devfreq(devfreq);
308 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
310 queue_delayed_work(devfreq_wq, &devfreq->work,
311 msecs_to_jiffies(devfreq->profile->polling_ms));
312 mutex_unlock(&devfreq->lock);
316 * devfreq_monitor_start() - Start load monitoring of devfreq instance
317 * @devfreq: the devfreq instance.
319 * Helper function for starting devfreq device load monitoing. By
320 * default delayed work based monitoring is supported. Function
321 * to be called from governor in response to DEVFREQ_GOV_START
322 * event when device is added to devfreq framework.
324 void devfreq_monitor_start(struct devfreq *devfreq)
326 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
327 if (devfreq->profile->polling_ms)
328 queue_delayed_work(devfreq_wq, &devfreq->work,
329 msecs_to_jiffies(devfreq->profile->polling_ms));
331 EXPORT_SYMBOL(devfreq_monitor_start);
334 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
335 * @devfreq: the devfreq instance.
337 * Helper function to stop devfreq device load monitoing. Function
338 * to be called from governor in response to DEVFREQ_GOV_STOP
339 * event when device is removed from devfreq framework.
341 void devfreq_monitor_stop(struct devfreq *devfreq)
343 cancel_delayed_work_sync(&devfreq->work);
345 EXPORT_SYMBOL(devfreq_monitor_stop);
348 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
349 * @devfreq: the devfreq instance.
351 * Helper function to suspend devfreq device load monitoing. Function
352 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
353 * event or when polling interval is set to zero.
355 * Note: Though this function is same as devfreq_monitor_stop(),
356 * intentionally kept separate to provide hooks for collecting
357 * transition statistics.
359 void devfreq_monitor_suspend(struct devfreq *devfreq)
361 mutex_lock(&devfreq->lock);
362 if (devfreq->stop_polling) {
363 mutex_unlock(&devfreq->lock);
367 devfreq_update_status(devfreq, devfreq->previous_freq);
368 devfreq->stop_polling = true;
369 mutex_unlock(&devfreq->lock);
370 cancel_delayed_work_sync(&devfreq->work);
372 EXPORT_SYMBOL(devfreq_monitor_suspend);
375 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
376 * @devfreq: the devfreq instance.
378 * Helper function to resume devfreq device load monitoing. Function
379 * to be called from governor in response to DEVFREQ_GOV_RESUME
380 * event or when polling interval is set to non-zero.
382 void devfreq_monitor_resume(struct devfreq *devfreq)
386 mutex_lock(&devfreq->lock);
387 if (!devfreq->stop_polling)
390 if (!delayed_work_pending(&devfreq->work) &&
391 devfreq->profile->polling_ms)
392 queue_delayed_work(devfreq_wq, &devfreq->work,
393 msecs_to_jiffies(devfreq->profile->polling_ms));
395 devfreq->last_stat_updated = jiffies;
396 devfreq->stop_polling = false;
398 if (devfreq->profile->get_cur_freq &&
399 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
400 devfreq->previous_freq = freq;
403 mutex_unlock(&devfreq->lock);
405 EXPORT_SYMBOL(devfreq_monitor_resume);
408 * devfreq_interval_update() - Update device devfreq monitoring interval
409 * @devfreq: the devfreq instance.
410 * @delay: new polling interval to be set.
412 * Helper function to set new load monitoring polling interval. Function
413 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
415 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
417 unsigned int cur_delay = devfreq->profile->polling_ms;
418 unsigned int new_delay = *delay;
420 mutex_lock(&devfreq->lock);
421 devfreq->profile->polling_ms = new_delay;
423 if (devfreq->stop_polling)
426 /* if new delay is zero, stop polling */
428 mutex_unlock(&devfreq->lock);
429 cancel_delayed_work_sync(&devfreq->work);
433 /* if current delay is zero, start polling with new delay */
435 queue_delayed_work(devfreq_wq, &devfreq->work,
436 msecs_to_jiffies(devfreq->profile->polling_ms));
440 /* if current delay is greater than new delay, restart polling */
441 if (cur_delay > new_delay) {
442 mutex_unlock(&devfreq->lock);
443 cancel_delayed_work_sync(&devfreq->work);
444 mutex_lock(&devfreq->lock);
445 if (!devfreq->stop_polling)
446 queue_delayed_work(devfreq_wq, &devfreq->work,
447 msecs_to_jiffies(devfreq->profile->polling_ms));
450 mutex_unlock(&devfreq->lock);
452 EXPORT_SYMBOL(devfreq_interval_update);
455 * devfreq_notifier_call() - Notify that the device frequency requirements
456 * has been changed out of devfreq framework.
457 * @nb: the notifier_block (supposed to be devfreq->nb)
461 * Called by a notifier that uses devfreq->nb.
463 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
466 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
469 mutex_lock(&devfreq->lock);
470 ret = update_devfreq(devfreq);
471 mutex_unlock(&devfreq->lock);
477 * devfreq_dev_release() - Callback for struct device to release the device.
478 * @dev: the devfreq device
480 * Remove devfreq from the list and release its resources.
482 static void devfreq_dev_release(struct device *dev)
484 struct devfreq *devfreq = to_devfreq(dev);
486 mutex_lock(&devfreq_list_lock);
487 list_del(&devfreq->node);
488 mutex_unlock(&devfreq_list_lock);
490 if (devfreq->governor)
491 devfreq->governor->event_handler(devfreq,
492 DEVFREQ_GOV_STOP, NULL);
494 if (devfreq->profile->exit)
495 devfreq->profile->exit(devfreq->dev.parent);
497 mutex_destroy(&devfreq->lock);
502 * devfreq_add_device() - Add devfreq feature to the device
503 * @dev: the device to add devfreq feature.
504 * @profile: device-specific profile to run devfreq.
505 * @governor_name: name of the policy to choose frequency.
506 * @data: private data for the governor. The devfreq framework does not
509 struct devfreq *devfreq_add_device(struct device *dev,
510 struct devfreq_dev_profile *profile,
511 const char *governor_name,
514 struct devfreq *devfreq;
515 struct devfreq_governor *governor;
518 if (!dev || !profile || !governor_name) {
519 dev_err(dev, "%s: Invalid parameters.\n", __func__);
520 return ERR_PTR(-EINVAL);
523 mutex_lock(&devfreq_list_lock);
524 devfreq = find_device_devfreq(dev);
525 mutex_unlock(&devfreq_list_lock);
526 if (!IS_ERR(devfreq)) {
527 dev_err(dev, "%s: Unable to create devfreq for the device.\n",
533 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
539 mutex_init(&devfreq->lock);
540 mutex_lock(&devfreq->lock);
541 devfreq->dev.parent = dev;
542 devfreq->dev.class = devfreq_class;
543 devfreq->dev.release = devfreq_dev_release;
544 INIT_LIST_HEAD(&devfreq->node);
545 devfreq->profile = profile;
546 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
547 devfreq->previous_freq = profile->initial_freq;
548 devfreq->last_status.current_frequency = profile->initial_freq;
549 devfreq->data = data;
550 devfreq->nb.notifier_call = devfreq_notifier_call;
552 if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
553 mutex_unlock(&devfreq->lock);
554 devfreq_set_freq_table(devfreq);
555 mutex_lock(&devfreq->lock);
558 dev_set_name(&devfreq->dev, "%s", dev_name(dev));
559 err = device_register(&devfreq->dev);
561 mutex_unlock(&devfreq->lock);
565 devfreq->trans_table = devm_kzalloc(&devfreq->dev,
566 sizeof(unsigned int) *
567 devfreq->profile->max_state *
568 devfreq->profile->max_state,
570 devfreq->time_in_state = devm_kzalloc(&devfreq->dev,
571 sizeof(unsigned long) *
572 devfreq->profile->max_state,
574 devfreq->last_stat_updated = jiffies;
576 srcu_init_notifier_head(&devfreq->transition_notifier_list);
578 mutex_unlock(&devfreq->lock);
580 mutex_lock(&devfreq_list_lock);
581 list_add(&devfreq->node, &devfreq_list);
583 governor = find_devfreq_governor(devfreq->governor_name);
584 if (IS_ERR(governor)) {
585 dev_err(dev, "%s: Unable to find governor for the device\n",
587 err = PTR_ERR(governor);
591 devfreq->governor = governor;
592 err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
595 dev_err(dev, "%s: Unable to start governor for the device\n",
599 mutex_unlock(&devfreq_list_lock);
604 list_del(&devfreq->node);
605 mutex_unlock(&devfreq_list_lock);
607 device_unregister(&devfreq->dev);
614 EXPORT_SYMBOL(devfreq_add_device);
617 * devfreq_remove_device() - Remove devfreq feature from a device.
618 * @devfreq: the devfreq instance to be removed
620 * The opposite of devfreq_add_device().
622 int devfreq_remove_device(struct devfreq *devfreq)
627 device_unregister(&devfreq->dev);
631 EXPORT_SYMBOL(devfreq_remove_device);
633 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
635 struct devfreq **r = res;
637 if (WARN_ON(!r || !*r))
643 static void devm_devfreq_dev_release(struct device *dev, void *res)
645 devfreq_remove_device(*(struct devfreq **)res);
649 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
650 * @dev: the device to add devfreq feature.
651 * @profile: device-specific profile to run devfreq.
652 * @governor_name: name of the policy to choose frequency.
653 * @data: private data for the governor. The devfreq framework does not
656 * This function manages automatically the memory of devfreq device using device
657 * resource management and simplify the free operation for memory of devfreq
660 struct devfreq *devm_devfreq_add_device(struct device *dev,
661 struct devfreq_dev_profile *profile,
662 const char *governor_name,
665 struct devfreq **ptr, *devfreq;
667 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
669 return ERR_PTR(-ENOMEM);
671 devfreq = devfreq_add_device(dev, profile, governor_name, data);
672 if (IS_ERR(devfreq)) {
678 devres_add(dev, ptr);
682 EXPORT_SYMBOL(devm_devfreq_add_device);
686 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
687 * @dev - instance to the given device
688 * @index - index into list of devfreq
690 * return the instance of devfreq device
692 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
694 struct device_node *node;
695 struct devfreq *devfreq;
698 return ERR_PTR(-EINVAL);
701 return ERR_PTR(-EINVAL);
703 node = of_parse_phandle(dev->of_node, "devfreq", index);
705 return ERR_PTR(-ENODEV);
707 mutex_lock(&devfreq_list_lock);
708 list_for_each_entry(devfreq, &devfreq_list, node) {
709 if (devfreq->dev.parent
710 && devfreq->dev.parent->of_node == node) {
711 mutex_unlock(&devfreq_list_lock);
716 mutex_unlock(&devfreq_list_lock);
719 return ERR_PTR(-EPROBE_DEFER);
722 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
724 return ERR_PTR(-ENODEV);
726 #endif /* CONFIG_OF */
727 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
730 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
731 * @dev: the device to add devfreq feature.
732 * @devfreq: the devfreq instance to be removed
734 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
736 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
737 devm_devfreq_dev_match, devfreq));
739 EXPORT_SYMBOL(devm_devfreq_remove_device);
742 * devfreq_suspend_device() - Suspend devfreq of a device.
743 * @devfreq: the devfreq instance to be suspended
745 * This function is intended to be called by the pm callbacks
746 * (e.g., runtime_suspend, suspend) of the device driver that
749 int devfreq_suspend_device(struct devfreq *devfreq)
754 if (!devfreq->governor)
757 return devfreq->governor->event_handler(devfreq,
758 DEVFREQ_GOV_SUSPEND, NULL);
760 EXPORT_SYMBOL(devfreq_suspend_device);
763 * devfreq_resume_device() - Resume devfreq of a device.
764 * @devfreq: the devfreq instance to be resumed
766 * This function is intended to be called by the pm callbacks
767 * (e.g., runtime_resume, resume) of the device driver that
770 int devfreq_resume_device(struct devfreq *devfreq)
775 if (!devfreq->governor)
778 return devfreq->governor->event_handler(devfreq,
779 DEVFREQ_GOV_RESUME, NULL);
781 EXPORT_SYMBOL(devfreq_resume_device);
784 * devfreq_add_governor() - Add devfreq governor
785 * @governor: the devfreq governor to be added
787 int devfreq_add_governor(struct devfreq_governor *governor)
789 struct devfreq_governor *g;
790 struct devfreq *devfreq;
794 pr_err("%s: Invalid parameters.\n", __func__);
798 mutex_lock(&devfreq_list_lock);
799 g = find_devfreq_governor(governor->name);
801 pr_err("%s: governor %s already registered\n", __func__,
807 list_add(&governor->node, &devfreq_governor_list);
809 list_for_each_entry(devfreq, &devfreq_list, node) {
811 struct device *dev = devfreq->dev.parent;
813 if (!strncmp(devfreq->governor_name, governor->name,
815 /* The following should never occur */
816 if (devfreq->governor) {
818 "%s: Governor %s already present\n",
819 __func__, devfreq->governor->name);
820 ret = devfreq->governor->event_handler(devfreq,
821 DEVFREQ_GOV_STOP, NULL);
824 "%s: Governor %s stop = %d\n",
826 devfreq->governor->name, ret);
830 devfreq->governor = governor;
831 ret = devfreq->governor->event_handler(devfreq,
832 DEVFREQ_GOV_START, NULL);
834 dev_warn(dev, "%s: Governor %s start=%d\n",
835 __func__, devfreq->governor->name,
842 mutex_unlock(&devfreq_list_lock);
846 EXPORT_SYMBOL(devfreq_add_governor);
849 * devfreq_remove_governor() - Remove devfreq feature from a device.
850 * @governor: the devfreq governor to be removed
852 int devfreq_remove_governor(struct devfreq_governor *governor)
854 struct devfreq_governor *g;
855 struct devfreq *devfreq;
859 pr_err("%s: Invalid parameters.\n", __func__);
863 mutex_lock(&devfreq_list_lock);
864 g = find_devfreq_governor(governor->name);
866 pr_err("%s: governor %s not registered\n", __func__,
871 list_for_each_entry(devfreq, &devfreq_list, node) {
873 struct device *dev = devfreq->dev.parent;
875 if (!strncmp(devfreq->governor_name, governor->name,
877 /* we should have a devfreq governor! */
878 if (!devfreq->governor) {
879 dev_warn(dev, "%s: Governor %s NOT present\n",
880 __func__, governor->name);
884 ret = devfreq->governor->event_handler(devfreq,
885 DEVFREQ_GOV_STOP, NULL);
887 dev_warn(dev, "%s: Governor %s stop=%d\n",
888 __func__, devfreq->governor->name,
891 devfreq->governor = NULL;
895 list_del(&governor->node);
897 mutex_unlock(&devfreq_list_lock);
901 EXPORT_SYMBOL(devfreq_remove_governor);
903 static ssize_t name_show(struct device *dev,
904 struct device_attribute *attr, char *buf)
906 struct devfreq *devfreq = to_devfreq(dev);
907 return sprintf(buf, "%s\n", dev_name(devfreq->dev.parent));
909 static DEVICE_ATTR_RO(name);
911 static ssize_t governor_show(struct device *dev,
912 struct device_attribute *attr, char *buf)
914 if (!to_devfreq(dev)->governor)
917 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
920 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
921 const char *buf, size_t count)
923 struct devfreq *df = to_devfreq(dev);
925 char str_governor[DEVFREQ_NAME_LEN + 1];
926 struct devfreq_governor *governor;
928 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
932 mutex_lock(&devfreq_list_lock);
933 governor = find_devfreq_governor(str_governor);
934 if (IS_ERR(governor)) {
935 ret = PTR_ERR(governor);
938 if (df->governor == governor) {
941 } else if ((df->governor && df->governor->immutable) ||
942 governor->immutable) {
948 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
950 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
951 __func__, df->governor->name, ret);
955 df->governor = governor;
956 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
957 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
959 dev_warn(dev, "%s: Governor %s not started(%d)\n",
960 __func__, df->governor->name, ret);
962 mutex_unlock(&devfreq_list_lock);
968 static DEVICE_ATTR_RW(governor);
970 static ssize_t available_governors_show(struct device *d,
971 struct device_attribute *attr,
974 struct devfreq *df = to_devfreq(d);
977 mutex_lock(&devfreq_list_lock);
980 * The devfreq with immutable governor (e.g., passive) shows
983 if (df->governor && df->governor->immutable) {
984 count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
985 "%s ", df->governor_name);
987 * The devfreq device shows the registered governor except for
988 * immutable governors such as passive governor .
991 struct devfreq_governor *governor;
993 list_for_each_entry(governor, &devfreq_governor_list, node) {
994 if (governor->immutable)
996 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
997 "%s ", governor->name);
1001 mutex_unlock(&devfreq_list_lock);
1003 /* Truncate the trailing space */
1007 count += sprintf(&buf[count], "\n");
1011 static DEVICE_ATTR_RO(available_governors);
1013 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1017 struct devfreq *devfreq = to_devfreq(dev);
1019 if (devfreq->profile->get_cur_freq &&
1020 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
1021 return sprintf(buf, "%lu\n", freq);
1023 return sprintf(buf, "%lu\n", devfreq->previous_freq);
1025 static DEVICE_ATTR_RO(cur_freq);
1027 static ssize_t target_freq_show(struct device *dev,
1028 struct device_attribute *attr, char *buf)
1030 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
1032 static DEVICE_ATTR_RO(target_freq);
1034 static ssize_t polling_interval_show(struct device *dev,
1035 struct device_attribute *attr, char *buf)
1037 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
1040 static ssize_t polling_interval_store(struct device *dev,
1041 struct device_attribute *attr,
1042 const char *buf, size_t count)
1044 struct devfreq *df = to_devfreq(dev);
1051 ret = sscanf(buf, "%u", &value);
1055 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
1060 static DEVICE_ATTR_RW(polling_interval);
1062 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1063 const char *buf, size_t count)
1065 struct devfreq *df = to_devfreq(dev);
1066 unsigned long value;
1070 ret = sscanf(buf, "%lu", &value);
1074 mutex_lock(&df->lock);
1076 if (value && max && value > max) {
1081 df->min_freq = value;
1085 mutex_unlock(&df->lock);
1089 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1090 const char *buf, size_t count)
1092 struct devfreq *df = to_devfreq(dev);
1093 unsigned long value;
1097 ret = sscanf(buf, "%lu", &value);
1101 mutex_lock(&df->lock);
1103 if (value && min && value < min) {
1108 df->max_freq = value;
1112 mutex_unlock(&df->lock);
1116 #define show_one(name) \
1117 static ssize_t name##_show \
1118 (struct device *dev, struct device_attribute *attr, char *buf) \
1120 return sprintf(buf, "%lu\n", to_devfreq(dev)->name); \
1125 static DEVICE_ATTR_RW(min_freq);
1126 static DEVICE_ATTR_RW(max_freq);
1128 static ssize_t available_frequencies_show(struct device *d,
1129 struct device_attribute *attr,
1132 struct devfreq *df = to_devfreq(d);
1133 struct device *dev = df->dev.parent;
1134 struct dev_pm_opp *opp;
1136 unsigned long freq = 0;
1139 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1143 dev_pm_opp_put(opp);
1144 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1149 /* Truncate the trailing space */
1153 count += sprintf(&buf[count], "\n");
1157 static DEVICE_ATTR_RO(available_frequencies);
1159 static ssize_t trans_stat_show(struct device *dev,
1160 struct device_attribute *attr, char *buf)
1162 struct devfreq *devfreq = to_devfreq(dev);
1165 unsigned int max_state = devfreq->profile->max_state;
1168 return sprintf(buf, "Not Supported.\n");
1170 mutex_lock(&devfreq->lock);
1171 if (!devfreq->stop_polling &&
1172 devfreq_update_status(devfreq, devfreq->previous_freq)) {
1173 mutex_unlock(&devfreq->lock);
1176 mutex_unlock(&devfreq->lock);
1178 len = sprintf(buf, " From : To\n");
1179 len += sprintf(buf + len, " :");
1180 for (i = 0; i < max_state; i++)
1181 len += sprintf(buf + len, "%10lu",
1182 devfreq->profile->freq_table[i]);
1184 len += sprintf(buf + len, " time(ms)\n");
1186 for (i = 0; i < max_state; i++) {
1187 if (devfreq->profile->freq_table[i]
1188 == devfreq->previous_freq) {
1189 len += sprintf(buf + len, "*");
1191 len += sprintf(buf + len, " ");
1193 len += sprintf(buf + len, "%10lu:",
1194 devfreq->profile->freq_table[i]);
1195 for (j = 0; j < max_state; j++)
1196 len += sprintf(buf + len, "%10u",
1197 devfreq->trans_table[(i * max_state) + j]);
1198 len += sprintf(buf + len, "%10u\n",
1199 jiffies_to_msecs(devfreq->time_in_state[i]));
1202 len += sprintf(buf + len, "Total transition : %u\n",
1203 devfreq->total_trans);
1206 static DEVICE_ATTR_RO(trans_stat);
1208 static struct attribute *devfreq_attrs[] = {
1209 &dev_attr_name.attr,
1210 &dev_attr_governor.attr,
1211 &dev_attr_available_governors.attr,
1212 &dev_attr_cur_freq.attr,
1213 &dev_attr_available_frequencies.attr,
1214 &dev_attr_target_freq.attr,
1215 &dev_attr_polling_interval.attr,
1216 &dev_attr_min_freq.attr,
1217 &dev_attr_max_freq.attr,
1218 &dev_attr_trans_stat.attr,
1221 ATTRIBUTE_GROUPS(devfreq);
1223 static int __init devfreq_init(void)
1225 devfreq_class = class_create(THIS_MODULE, "devfreq");
1226 if (IS_ERR(devfreq_class)) {
1227 pr_err("%s: couldn't create class\n", __FILE__);
1228 return PTR_ERR(devfreq_class);
1231 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1233 class_destroy(devfreq_class);
1234 pr_err("%s: couldn't create workqueue\n", __FILE__);
1237 devfreq_class->dev_groups = devfreq_groups;
1241 subsys_initcall(devfreq_init);
1244 * The following are helper functions for devfreq user device drivers with
1249 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1250 * freq value given to target callback.
1251 * @dev: The devfreq user device. (parent of devfreq)
1252 * @freq: The frequency given to target function
1253 * @flags: Flags handed from devfreq framework.
1255 * The callers are required to call dev_pm_opp_put() for the returned OPP after
1258 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1259 unsigned long *freq,
1262 struct dev_pm_opp *opp;
1264 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1265 /* The freq is an upper bound. opp should be lower */
1266 opp = dev_pm_opp_find_freq_floor(dev, freq);
1268 /* If not available, use the closest opp */
1269 if (opp == ERR_PTR(-ERANGE))
1270 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1272 /* The freq is an lower bound. opp should be higher */
1273 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1275 /* If not available, use the closest opp */
1276 if (opp == ERR_PTR(-ERANGE))
1277 opp = dev_pm_opp_find_freq_floor(dev, freq);
1282 EXPORT_SYMBOL(devfreq_recommended_opp);
1285 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1286 * for any changes in the OPP availability
1288 * @dev: The devfreq user device. (parent of devfreq)
1289 * @devfreq: The devfreq object.
1291 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1293 return dev_pm_opp_register_notifier(dev, &devfreq->nb);
1295 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1298 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1299 * notified for any changes in the OPP
1300 * availability changes anymore.
1301 * @dev: The devfreq user device. (parent of devfreq)
1302 * @devfreq: The devfreq object.
1304 * At exit() callback of devfreq_dev_profile, this must be included if
1305 * devfreq_recommended_opp is used.
1307 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1309 return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
1311 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1313 static void devm_devfreq_opp_release(struct device *dev, void *res)
1315 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1319 * devm_ devfreq_register_opp_notifier()
1320 * - Resource-managed devfreq_register_opp_notifier()
1321 * @dev: The devfreq user device. (parent of devfreq)
1322 * @devfreq: The devfreq object.
1324 int devm_devfreq_register_opp_notifier(struct device *dev,
1325 struct devfreq *devfreq)
1327 struct devfreq **ptr;
1330 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1334 ret = devfreq_register_opp_notifier(dev, devfreq);
1341 devres_add(dev, ptr);
1345 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1348 * devm_devfreq_unregister_opp_notifier()
1349 * - Resource-managed devfreq_unregister_opp_notifier()
1350 * @dev: The devfreq user device. (parent of devfreq)
1351 * @devfreq: The devfreq object.
1353 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1354 struct devfreq *devfreq)
1356 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1357 devm_devfreq_dev_match, devfreq));
1359 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1362 * devfreq_register_notifier() - Register a driver with devfreq
1363 * @devfreq: The devfreq object.
1364 * @nb: The notifier block to register.
1365 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1367 int devfreq_register_notifier(struct devfreq *devfreq,
1368 struct notifier_block *nb,
1377 case DEVFREQ_TRANSITION_NOTIFIER:
1378 ret = srcu_notifier_chain_register(
1379 &devfreq->transition_notifier_list, nb);
1387 EXPORT_SYMBOL(devfreq_register_notifier);
1390 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1391 * @devfreq: The devfreq object.
1392 * @nb: The notifier block to be unregistered.
1393 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1395 int devfreq_unregister_notifier(struct devfreq *devfreq,
1396 struct notifier_block *nb,
1405 case DEVFREQ_TRANSITION_NOTIFIER:
1406 ret = srcu_notifier_chain_unregister(
1407 &devfreq->transition_notifier_list, nb);
1415 EXPORT_SYMBOL(devfreq_unregister_notifier);
1417 struct devfreq_notifier_devres {
1418 struct devfreq *devfreq;
1419 struct notifier_block *nb;
1423 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1425 struct devfreq_notifier_devres *this = res;
1427 devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1431 * devm_devfreq_register_notifier()
1432 - Resource-managed devfreq_register_notifier()
1433 * @dev: The devfreq user device. (parent of devfreq)
1434 * @devfreq: The devfreq object.
1435 * @nb: The notifier block to be unregistered.
1436 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1438 int devm_devfreq_register_notifier(struct device *dev,
1439 struct devfreq *devfreq,
1440 struct notifier_block *nb,
1443 struct devfreq_notifier_devres *ptr;
1446 ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1451 ret = devfreq_register_notifier(devfreq, nb, list);
1457 ptr->devfreq = devfreq;
1460 devres_add(dev, ptr);
1464 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1467 * devm_devfreq_unregister_notifier()
1468 - Resource-managed devfreq_unregister_notifier()
1469 * @dev: The devfreq user device. (parent of devfreq)
1470 * @devfreq: The devfreq object.
1471 * @nb: The notifier block to be unregistered.
1472 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1474 void devm_devfreq_unregister_notifier(struct device *dev,
1475 struct devfreq *devfreq,
1476 struct notifier_block *nb,
1479 WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1480 devm_devfreq_dev_match, devfreq));
1482 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);