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_update_status() - Update statistics of devfreq behavior
90 * @devfreq: the devfreq instance
91 * @freq: the update target frequency
93 static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
95 int lev, prev_lev, ret = 0;
96 unsigned long cur_time;
100 prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
106 devfreq->time_in_state[prev_lev] +=
107 cur_time - devfreq->last_stat_updated;
109 lev = devfreq_get_freq_level(devfreq, freq);
115 if (lev != prev_lev) {
116 devfreq->trans_table[(prev_lev *
117 devfreq->profile->max_state) + lev]++;
118 devfreq->total_trans++;
122 devfreq->last_stat_updated = cur_time;
127 * find_devfreq_governor() - find devfreq governor from name
128 * @name: name of the governor
130 * Search the list of devfreq governors and return the matched
131 * governor's pointer. devfreq_list_lock should be held by the caller.
133 static struct devfreq_governor *find_devfreq_governor(const char *name)
135 struct devfreq_governor *tmp_governor;
137 if (IS_ERR_OR_NULL(name)) {
138 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
139 return ERR_PTR(-EINVAL);
141 WARN(!mutex_is_locked(&devfreq_list_lock),
142 "devfreq_list_lock must be locked.");
144 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
145 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
149 return ERR_PTR(-ENODEV);
152 static int devfreq_notify_transition(struct devfreq *devfreq,
153 struct devfreq_freqs *freqs, unsigned int state)
159 case DEVFREQ_PRECHANGE:
160 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
161 DEVFREQ_PRECHANGE, freqs);
164 case DEVFREQ_POSTCHANGE:
165 srcu_notifier_call_chain(&devfreq->transition_notifier_list,
166 DEVFREQ_POSTCHANGE, freqs);
175 /* Load monitoring helper functions for governors use */
178 * update_devfreq() - Reevaluate the device and configure frequency.
179 * @devfreq: the devfreq instance.
181 * Note: Lock devfreq->lock before calling update_devfreq
182 * This function is exported for governors.
184 int update_devfreq(struct devfreq *devfreq)
186 struct devfreq_freqs freqs;
187 unsigned long freq, cur_freq;
191 if (!mutex_is_locked(&devfreq->lock)) {
192 WARN(true, "devfreq->lock must be locked by the caller.\n");
196 if (!devfreq->governor)
199 /* Reevaluate the proper frequency */
200 err = devfreq->governor->get_target_freq(devfreq, &freq);
205 * Adjust the frequency with user freq and QoS.
207 * List from the highest priority
212 if (devfreq->min_freq && freq < devfreq->min_freq) {
213 freq = devfreq->min_freq;
214 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
216 if (devfreq->max_freq && freq > devfreq->max_freq) {
217 freq = devfreq->max_freq;
218 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
221 if (devfreq->profile->get_cur_freq)
222 devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
224 cur_freq = devfreq->previous_freq;
226 freqs.old = cur_freq;
228 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
230 err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
232 freqs.new = cur_freq;
233 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
238 devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
240 if (devfreq->profile->freq_table)
241 if (devfreq_update_status(devfreq, freq))
242 dev_err(&devfreq->dev,
243 "Couldn't update frequency transition information.\n");
245 devfreq->previous_freq = freq;
248 EXPORT_SYMBOL(update_devfreq);
251 * devfreq_monitor() - Periodically poll devfreq objects.
252 * @work: the work struct used to run devfreq_monitor periodically.
255 static void devfreq_monitor(struct work_struct *work)
258 struct devfreq *devfreq = container_of(work,
259 struct devfreq, work.work);
261 mutex_lock(&devfreq->lock);
262 err = update_devfreq(devfreq);
264 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
266 queue_delayed_work(devfreq_wq, &devfreq->work,
267 msecs_to_jiffies(devfreq->profile->polling_ms));
268 mutex_unlock(&devfreq->lock);
272 * devfreq_monitor_start() - Start load monitoring of devfreq instance
273 * @devfreq: the devfreq instance.
275 * Helper function for starting devfreq device load monitoing. By
276 * default delayed work based monitoring is supported. Function
277 * to be called from governor in response to DEVFREQ_GOV_START
278 * event when device is added to devfreq framework.
280 void devfreq_monitor_start(struct devfreq *devfreq)
282 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
283 if (devfreq->profile->polling_ms)
284 queue_delayed_work(devfreq_wq, &devfreq->work,
285 msecs_to_jiffies(devfreq->profile->polling_ms));
287 EXPORT_SYMBOL(devfreq_monitor_start);
290 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
291 * @devfreq: the devfreq instance.
293 * Helper function to stop devfreq device load monitoing. Function
294 * to be called from governor in response to DEVFREQ_GOV_STOP
295 * event when device is removed from devfreq framework.
297 void devfreq_monitor_stop(struct devfreq *devfreq)
299 cancel_delayed_work_sync(&devfreq->work);
301 EXPORT_SYMBOL(devfreq_monitor_stop);
304 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
305 * @devfreq: the devfreq instance.
307 * Helper function to suspend devfreq device load monitoing. Function
308 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
309 * event or when polling interval is set to zero.
311 * Note: Though this function is same as devfreq_monitor_stop(),
312 * intentionally kept separate to provide hooks for collecting
313 * transition statistics.
315 void devfreq_monitor_suspend(struct devfreq *devfreq)
317 mutex_lock(&devfreq->lock);
318 if (devfreq->stop_polling) {
319 mutex_unlock(&devfreq->lock);
323 devfreq_update_status(devfreq, devfreq->previous_freq);
324 devfreq->stop_polling = true;
325 mutex_unlock(&devfreq->lock);
326 cancel_delayed_work_sync(&devfreq->work);
328 EXPORT_SYMBOL(devfreq_monitor_suspend);
331 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
332 * @devfreq: the devfreq instance.
334 * Helper function to resume devfreq device load monitoing. Function
335 * to be called from governor in response to DEVFREQ_GOV_RESUME
336 * event or when polling interval is set to non-zero.
338 void devfreq_monitor_resume(struct devfreq *devfreq)
342 mutex_lock(&devfreq->lock);
343 if (!devfreq->stop_polling)
346 if (!delayed_work_pending(&devfreq->work) &&
347 devfreq->profile->polling_ms)
348 queue_delayed_work(devfreq_wq, &devfreq->work,
349 msecs_to_jiffies(devfreq->profile->polling_ms));
351 devfreq->last_stat_updated = jiffies;
352 devfreq->stop_polling = false;
354 if (devfreq->profile->get_cur_freq &&
355 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
356 devfreq->previous_freq = freq;
359 mutex_unlock(&devfreq->lock);
361 EXPORT_SYMBOL(devfreq_monitor_resume);
364 * devfreq_interval_update() - Update device devfreq monitoring interval
365 * @devfreq: the devfreq instance.
366 * @delay: new polling interval to be set.
368 * Helper function to set new load monitoring polling interval. Function
369 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
371 void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
373 unsigned int cur_delay = devfreq->profile->polling_ms;
374 unsigned int new_delay = *delay;
376 mutex_lock(&devfreq->lock);
377 devfreq->profile->polling_ms = new_delay;
379 if (devfreq->stop_polling)
382 /* if new delay is zero, stop polling */
384 mutex_unlock(&devfreq->lock);
385 cancel_delayed_work_sync(&devfreq->work);
389 /* if current delay is zero, start polling with new delay */
391 queue_delayed_work(devfreq_wq, &devfreq->work,
392 msecs_to_jiffies(devfreq->profile->polling_ms));
396 /* if current delay is greater than new delay, restart polling */
397 if (cur_delay > new_delay) {
398 mutex_unlock(&devfreq->lock);
399 cancel_delayed_work_sync(&devfreq->work);
400 mutex_lock(&devfreq->lock);
401 if (!devfreq->stop_polling)
402 queue_delayed_work(devfreq_wq, &devfreq->work,
403 msecs_to_jiffies(devfreq->profile->polling_ms));
406 mutex_unlock(&devfreq->lock);
408 EXPORT_SYMBOL(devfreq_interval_update);
411 * devfreq_notifier_call() - Notify that the device frequency requirements
412 * has been changed out of devfreq framework.
413 * @nb: the notifier_block (supposed to be devfreq->nb)
417 * Called by a notifier that uses devfreq->nb.
419 static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
422 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
425 mutex_lock(&devfreq->lock);
426 ret = update_devfreq(devfreq);
427 mutex_unlock(&devfreq->lock);
433 * _remove_devfreq() - Remove devfreq from the list and release its resources.
434 * @devfreq: the devfreq struct
436 static void _remove_devfreq(struct devfreq *devfreq)
438 mutex_lock(&devfreq_list_lock);
439 if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
440 mutex_unlock(&devfreq_list_lock);
441 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
444 list_del(&devfreq->node);
445 mutex_unlock(&devfreq_list_lock);
447 if (devfreq->governor)
448 devfreq->governor->event_handler(devfreq,
449 DEVFREQ_GOV_STOP, NULL);
451 if (devfreq->profile->exit)
452 devfreq->profile->exit(devfreq->dev.parent);
454 mutex_destroy(&devfreq->lock);
459 * devfreq_dev_release() - Callback for struct device to release the device.
460 * @dev: the devfreq device
462 * This calls _remove_devfreq() if _remove_devfreq() is not called.
464 static void devfreq_dev_release(struct device *dev)
466 struct devfreq *devfreq = to_devfreq(dev);
468 _remove_devfreq(devfreq);
472 * devfreq_add_device() - Add devfreq feature to the device
473 * @dev: the device to add devfreq feature.
474 * @profile: device-specific profile to run devfreq.
475 * @governor_name: name of the policy to choose frequency.
476 * @data: private data for the governor. The devfreq framework does not
479 struct devfreq *devfreq_add_device(struct device *dev,
480 struct devfreq_dev_profile *profile,
481 const char *governor_name,
484 struct devfreq *devfreq;
485 struct devfreq_governor *governor;
488 if (!dev || !profile || !governor_name) {
489 dev_err(dev, "%s: Invalid parameters.\n", __func__);
490 return ERR_PTR(-EINVAL);
493 mutex_lock(&devfreq_list_lock);
494 devfreq = find_device_devfreq(dev);
495 mutex_unlock(&devfreq_list_lock);
496 if (!IS_ERR(devfreq)) {
497 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
502 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
504 dev_err(dev, "%s: Unable to create devfreq for the device\n",
510 mutex_init(&devfreq->lock);
511 mutex_lock(&devfreq->lock);
512 devfreq->dev.parent = dev;
513 devfreq->dev.class = devfreq_class;
514 devfreq->dev.release = devfreq_dev_release;
515 devfreq->profile = profile;
516 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
517 devfreq->previous_freq = profile->initial_freq;
518 devfreq->data = data;
519 devfreq->nb.notifier_call = devfreq_notifier_call;
521 devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) *
522 devfreq->profile->max_state *
523 devfreq->profile->max_state,
525 devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned long) *
526 devfreq->profile->max_state,
528 devfreq->last_stat_updated = jiffies;
530 dev_set_name(&devfreq->dev, "%s", dev_name(dev));
531 err = device_register(&devfreq->dev);
533 put_device(&devfreq->dev);
534 mutex_unlock(&devfreq->lock);
538 srcu_init_notifier_head(&devfreq->transition_notifier_list);
540 mutex_unlock(&devfreq->lock);
542 mutex_lock(&devfreq_list_lock);
543 list_add(&devfreq->node, &devfreq_list);
545 governor = find_devfreq_governor(devfreq->governor_name);
546 if (!IS_ERR(governor))
547 devfreq->governor = governor;
548 if (devfreq->governor)
549 err = devfreq->governor->event_handler(devfreq,
550 DEVFREQ_GOV_START, NULL);
551 mutex_unlock(&devfreq_list_lock);
553 dev_err(dev, "%s: Unable to start governor for the device\n",
561 list_del(&devfreq->node);
562 device_unregister(&devfreq->dev);
567 EXPORT_SYMBOL(devfreq_add_device);
570 * devfreq_remove_device() - Remove devfreq feature from a device.
571 * @devfreq: the devfreq instance to be removed
573 * The opposite of devfreq_add_device().
575 int devfreq_remove_device(struct devfreq *devfreq)
580 device_unregister(&devfreq->dev);
581 put_device(&devfreq->dev);
585 EXPORT_SYMBOL(devfreq_remove_device);
587 static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
589 struct devfreq **r = res;
591 if (WARN_ON(!r || !*r))
597 static void devm_devfreq_dev_release(struct device *dev, void *res)
599 devfreq_remove_device(*(struct devfreq **)res);
603 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
604 * @dev: the device to add devfreq feature.
605 * @profile: device-specific profile to run devfreq.
606 * @governor_name: name of the policy to choose frequency.
607 * @data: private data for the governor. The devfreq framework does not
610 * This function manages automatically the memory of devfreq device using device
611 * resource management and simplify the free operation for memory of devfreq
614 struct devfreq *devm_devfreq_add_device(struct device *dev,
615 struct devfreq_dev_profile *profile,
616 const char *governor_name,
619 struct devfreq **ptr, *devfreq;
621 ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
623 return ERR_PTR(-ENOMEM);
625 devfreq = devfreq_add_device(dev, profile, governor_name, data);
626 if (IS_ERR(devfreq)) {
628 return ERR_PTR(-ENOMEM);
632 devres_add(dev, ptr);
636 EXPORT_SYMBOL(devm_devfreq_add_device);
640 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
641 * @dev - instance to the given device
642 * @index - index into list of devfreq
644 * return the instance of devfreq device
646 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
648 struct device_node *node;
649 struct devfreq *devfreq;
652 return ERR_PTR(-EINVAL);
655 return ERR_PTR(-EINVAL);
657 node = of_parse_phandle(dev->of_node, "devfreq", index);
659 return ERR_PTR(-ENODEV);
661 mutex_lock(&devfreq_list_lock);
662 list_for_each_entry(devfreq, &devfreq_list, node) {
663 if (devfreq->dev.parent
664 && devfreq->dev.parent->of_node == node) {
665 mutex_unlock(&devfreq_list_lock);
670 mutex_unlock(&devfreq_list_lock);
673 return ERR_PTR(-EPROBE_DEFER);
676 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
678 return ERR_PTR(-ENODEV);
680 #endif /* CONFIG_OF */
681 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
684 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
685 * @dev: the device to add devfreq feature.
686 * @devfreq: the devfreq instance to be removed
688 void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
690 WARN_ON(devres_release(dev, devm_devfreq_dev_release,
691 devm_devfreq_dev_match, devfreq));
693 EXPORT_SYMBOL(devm_devfreq_remove_device);
696 * devfreq_suspend_device() - Suspend devfreq of a device.
697 * @devfreq: the devfreq instance to be suspended
699 * This function is intended to be called by the pm callbacks
700 * (e.g., runtime_suspend, suspend) of the device driver that
703 int devfreq_suspend_device(struct devfreq *devfreq)
708 if (!devfreq->governor)
711 return devfreq->governor->event_handler(devfreq,
712 DEVFREQ_GOV_SUSPEND, NULL);
714 EXPORT_SYMBOL(devfreq_suspend_device);
717 * devfreq_resume_device() - Resume devfreq of a device.
718 * @devfreq: the devfreq instance to be resumed
720 * This function is intended to be called by the pm callbacks
721 * (e.g., runtime_resume, resume) of the device driver that
724 int devfreq_resume_device(struct devfreq *devfreq)
729 if (!devfreq->governor)
732 return devfreq->governor->event_handler(devfreq,
733 DEVFREQ_GOV_RESUME, NULL);
735 EXPORT_SYMBOL(devfreq_resume_device);
738 * devfreq_add_governor() - Add devfreq governor
739 * @governor: the devfreq governor to be added
741 int devfreq_add_governor(struct devfreq_governor *governor)
743 struct devfreq_governor *g;
744 struct devfreq *devfreq;
748 pr_err("%s: Invalid parameters.\n", __func__);
752 mutex_lock(&devfreq_list_lock);
753 g = find_devfreq_governor(governor->name);
755 pr_err("%s: governor %s already registered\n", __func__,
761 list_add(&governor->node, &devfreq_governor_list);
763 list_for_each_entry(devfreq, &devfreq_list, node) {
765 struct device *dev = devfreq->dev.parent;
767 if (!strncmp(devfreq->governor_name, governor->name,
769 /* The following should never occur */
770 if (devfreq->governor) {
772 "%s: Governor %s already present\n",
773 __func__, devfreq->governor->name);
774 ret = devfreq->governor->event_handler(devfreq,
775 DEVFREQ_GOV_STOP, NULL);
778 "%s: Governor %s stop = %d\n",
780 devfreq->governor->name, ret);
784 devfreq->governor = governor;
785 ret = devfreq->governor->event_handler(devfreq,
786 DEVFREQ_GOV_START, NULL);
788 dev_warn(dev, "%s: Governor %s start=%d\n",
789 __func__, devfreq->governor->name,
796 mutex_unlock(&devfreq_list_lock);
800 EXPORT_SYMBOL(devfreq_add_governor);
803 * devfreq_remove_device() - Remove devfreq feature from a device.
804 * @governor: the devfreq governor to be removed
806 int devfreq_remove_governor(struct devfreq_governor *governor)
808 struct devfreq_governor *g;
809 struct devfreq *devfreq;
813 pr_err("%s: Invalid parameters.\n", __func__);
817 mutex_lock(&devfreq_list_lock);
818 g = find_devfreq_governor(governor->name);
820 pr_err("%s: governor %s not registered\n", __func__,
825 list_for_each_entry(devfreq, &devfreq_list, node) {
827 struct device *dev = devfreq->dev.parent;
829 if (!strncmp(devfreq->governor_name, governor->name,
831 /* we should have a devfreq governor! */
832 if (!devfreq->governor) {
833 dev_warn(dev, "%s: Governor %s NOT present\n",
834 __func__, governor->name);
838 ret = devfreq->governor->event_handler(devfreq,
839 DEVFREQ_GOV_STOP, NULL);
841 dev_warn(dev, "%s: Governor %s stop=%d\n",
842 __func__, devfreq->governor->name,
845 devfreq->governor = NULL;
849 list_del(&governor->node);
851 mutex_unlock(&devfreq_list_lock);
855 EXPORT_SYMBOL(devfreq_remove_governor);
857 static ssize_t governor_show(struct device *dev,
858 struct device_attribute *attr, char *buf)
860 if (!to_devfreq(dev)->governor)
863 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
866 static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
867 const char *buf, size_t count)
869 struct devfreq *df = to_devfreq(dev);
871 char str_governor[DEVFREQ_NAME_LEN + 1];
872 struct devfreq_governor *governor;
874 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
878 mutex_lock(&devfreq_list_lock);
879 governor = find_devfreq_governor(str_governor);
880 if (IS_ERR(governor)) {
881 ret = PTR_ERR(governor);
884 if (df->governor == governor) {
890 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
892 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
893 __func__, df->governor->name, ret);
897 df->governor = governor;
898 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
899 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
901 dev_warn(dev, "%s: Governor %s not started(%d)\n",
902 __func__, df->governor->name, ret);
904 mutex_unlock(&devfreq_list_lock);
910 static DEVICE_ATTR_RW(governor);
912 static ssize_t available_governors_show(struct device *d,
913 struct device_attribute *attr,
916 struct devfreq_governor *tmp_governor;
919 mutex_lock(&devfreq_list_lock);
920 list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
921 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
922 "%s ", tmp_governor->name);
923 mutex_unlock(&devfreq_list_lock);
925 /* Truncate the trailing space */
929 count += sprintf(&buf[count], "\n");
933 static DEVICE_ATTR_RO(available_governors);
935 static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
939 struct devfreq *devfreq = to_devfreq(dev);
941 if (devfreq->profile->get_cur_freq &&
942 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
943 return sprintf(buf, "%lu\n", freq);
945 return sprintf(buf, "%lu\n", devfreq->previous_freq);
947 static DEVICE_ATTR_RO(cur_freq);
949 static ssize_t target_freq_show(struct device *dev,
950 struct device_attribute *attr, char *buf)
952 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
954 static DEVICE_ATTR_RO(target_freq);
956 static ssize_t polling_interval_show(struct device *dev,
957 struct device_attribute *attr, char *buf)
959 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
962 static ssize_t polling_interval_store(struct device *dev,
963 struct device_attribute *attr,
964 const char *buf, size_t count)
966 struct devfreq *df = to_devfreq(dev);
973 ret = sscanf(buf, "%u", &value);
977 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
982 static DEVICE_ATTR_RW(polling_interval);
984 static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
985 const char *buf, size_t count)
987 struct devfreq *df = to_devfreq(dev);
992 ret = sscanf(buf, "%lu", &value);
996 mutex_lock(&df->lock);
998 if (value && max && value > max) {
1003 df->min_freq = value;
1007 mutex_unlock(&df->lock);
1011 static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1014 return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq);
1017 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1018 const char *buf, size_t count)
1020 struct devfreq *df = to_devfreq(dev);
1021 unsigned long value;
1025 ret = sscanf(buf, "%lu", &value);
1029 mutex_lock(&df->lock);
1031 if (value && min && value < min) {
1036 df->max_freq = value;
1040 mutex_unlock(&df->lock);
1043 static DEVICE_ATTR_RW(min_freq);
1045 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1048 return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
1050 static DEVICE_ATTR_RW(max_freq);
1052 static ssize_t available_frequencies_show(struct device *d,
1053 struct device_attribute *attr,
1056 struct devfreq *df = to_devfreq(d);
1057 struct device *dev = df->dev.parent;
1058 struct dev_pm_opp *opp;
1060 unsigned long freq = 0;
1064 opp = dev_pm_opp_find_freq_ceil(dev, &freq);
1068 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1074 /* Truncate the trailing space */
1078 count += sprintf(&buf[count], "\n");
1082 static DEVICE_ATTR_RO(available_frequencies);
1084 static ssize_t trans_stat_show(struct device *dev,
1085 struct device_attribute *attr, char *buf)
1087 struct devfreq *devfreq = to_devfreq(dev);
1090 unsigned int max_state = devfreq->profile->max_state;
1092 if (!devfreq->stop_polling &&
1093 devfreq_update_status(devfreq, devfreq->previous_freq))
1096 len = sprintf(buf, " From : To\n");
1097 len += sprintf(buf + len, " :");
1098 for (i = 0; i < max_state; i++)
1099 len += sprintf(buf + len, "%8u",
1100 devfreq->profile->freq_table[i]);
1102 len += sprintf(buf + len, " time(ms)\n");
1104 for (i = 0; i < max_state; i++) {
1105 if (devfreq->profile->freq_table[i]
1106 == devfreq->previous_freq) {
1107 len += sprintf(buf + len, "*");
1109 len += sprintf(buf + len, " ");
1111 len += sprintf(buf + len, "%8u:",
1112 devfreq->profile->freq_table[i]);
1113 for (j = 0; j < max_state; j++)
1114 len += sprintf(buf + len, "%8u",
1115 devfreq->trans_table[(i * max_state) + j]);
1116 len += sprintf(buf + len, "%10u\n",
1117 jiffies_to_msecs(devfreq->time_in_state[i]));
1120 len += sprintf(buf + len, "Total transition : %u\n",
1121 devfreq->total_trans);
1124 static DEVICE_ATTR_RO(trans_stat);
1126 static struct attribute *devfreq_attrs[] = {
1127 &dev_attr_governor.attr,
1128 &dev_attr_available_governors.attr,
1129 &dev_attr_cur_freq.attr,
1130 &dev_attr_available_frequencies.attr,
1131 &dev_attr_target_freq.attr,
1132 &dev_attr_polling_interval.attr,
1133 &dev_attr_min_freq.attr,
1134 &dev_attr_max_freq.attr,
1135 &dev_attr_trans_stat.attr,
1138 ATTRIBUTE_GROUPS(devfreq);
1140 static int __init devfreq_init(void)
1142 devfreq_class = class_create(THIS_MODULE, "devfreq");
1143 if (IS_ERR(devfreq_class)) {
1144 pr_err("%s: couldn't create class\n", __FILE__);
1145 return PTR_ERR(devfreq_class);
1148 devfreq_wq = create_freezable_workqueue("devfreq_wq");
1150 class_destroy(devfreq_class);
1151 pr_err("%s: couldn't create workqueue\n", __FILE__);
1154 devfreq_class->dev_groups = devfreq_groups;
1158 subsys_initcall(devfreq_init);
1160 static void __exit devfreq_exit(void)
1162 class_destroy(devfreq_class);
1163 destroy_workqueue(devfreq_wq);
1165 module_exit(devfreq_exit);
1168 * The followings are helper functions for devfreq user device drivers with
1173 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1174 * freq value given to target callback.
1175 * @dev: The devfreq user device. (parent of devfreq)
1176 * @freq: The frequency given to target function
1177 * @flags: Flags handed from devfreq framework.
1179 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1180 * protected pointer. The reason for the same is that the opp pointer which is
1181 * returned will remain valid for use with opp_get_{voltage, freq} only while
1182 * under the locked area. The pointer returned must be used prior to unlocking
1183 * with rcu_read_unlock() to maintain the integrity of the pointer.
1185 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
1186 unsigned long *freq,
1189 struct dev_pm_opp *opp;
1191 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1192 /* The freq is an upper bound. opp should be lower */
1193 opp = dev_pm_opp_find_freq_floor(dev, freq);
1195 /* If not available, use the closest opp */
1196 if (opp == ERR_PTR(-ERANGE))
1197 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1199 /* The freq is an lower bound. opp should be higher */
1200 opp = dev_pm_opp_find_freq_ceil(dev, freq);
1202 /* If not available, use the closest opp */
1203 if (opp == ERR_PTR(-ERANGE))
1204 opp = dev_pm_opp_find_freq_floor(dev, freq);
1209 EXPORT_SYMBOL(devfreq_recommended_opp);
1212 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1213 * for any changes in the OPP availability
1215 * @dev: The devfreq user device. (parent of devfreq)
1216 * @devfreq: The devfreq object.
1218 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1220 struct srcu_notifier_head *nh;
1224 nh = dev_pm_opp_get_notifier(dev);
1229 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1233 EXPORT_SYMBOL(devfreq_register_opp_notifier);
1236 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1237 * notified for any changes in the OPP
1238 * availability changes anymore.
1239 * @dev: The devfreq user device. (parent of devfreq)
1240 * @devfreq: The devfreq object.
1242 * At exit() callback of devfreq_dev_profile, this must be included if
1243 * devfreq_recommended_opp is used.
1245 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1247 struct srcu_notifier_head *nh;
1251 nh = dev_pm_opp_get_notifier(dev);
1256 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1260 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
1262 static void devm_devfreq_opp_release(struct device *dev, void *res)
1264 devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
1268 * devm_ devfreq_register_opp_notifier()
1269 * - Resource-managed devfreq_register_opp_notifier()
1270 * @dev: The devfreq user device. (parent of devfreq)
1271 * @devfreq: The devfreq object.
1273 int devm_devfreq_register_opp_notifier(struct device *dev,
1274 struct devfreq *devfreq)
1276 struct devfreq **ptr;
1279 ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
1283 ret = devfreq_register_opp_notifier(dev, devfreq);
1290 devres_add(dev, ptr);
1294 EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
1297 * devm_devfreq_unregister_opp_notifier()
1298 * - Resource-managed devfreq_unregister_opp_notifier()
1299 * @dev: The devfreq user device. (parent of devfreq)
1300 * @devfreq: The devfreq object.
1302 void devm_devfreq_unregister_opp_notifier(struct device *dev,
1303 struct devfreq *devfreq)
1305 WARN_ON(devres_release(dev, devm_devfreq_opp_release,
1306 devm_devfreq_dev_match, devfreq));
1308 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
1311 * devfreq_register_notifier() - Register a driver with devfreq
1312 * @devfreq: The devfreq object.
1313 * @nb: The notifier block to register.
1314 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1316 int devfreq_register_notifier(struct devfreq *devfreq,
1317 struct notifier_block *nb,
1326 case DEVFREQ_TRANSITION_NOTIFIER:
1327 ret = srcu_notifier_chain_register(
1328 &devfreq->transition_notifier_list, nb);
1336 EXPORT_SYMBOL(devfreq_register_notifier);
1339 * devfreq_unregister_notifier() - Unregister a driver with devfreq
1340 * @devfreq: The devfreq object.
1341 * @nb: The notifier block to be unregistered.
1342 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1344 int devfreq_unregister_notifier(struct devfreq *devfreq,
1345 struct notifier_block *nb,
1354 case DEVFREQ_TRANSITION_NOTIFIER:
1355 ret = srcu_notifier_chain_unregister(
1356 &devfreq->transition_notifier_list, nb);
1364 EXPORT_SYMBOL(devfreq_unregister_notifier);
1366 struct devfreq_notifier_devres {
1367 struct devfreq *devfreq;
1368 struct notifier_block *nb;
1372 static void devm_devfreq_notifier_release(struct device *dev, void *res)
1374 struct devfreq_notifier_devres *this = res;
1376 devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
1380 * devm_devfreq_register_notifier()
1381 - Resource-managed devfreq_register_notifier()
1382 * @dev: The devfreq user device. (parent of devfreq)
1383 * @devfreq: The devfreq object.
1384 * @nb: The notifier block to be unregistered.
1385 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1387 int devm_devfreq_register_notifier(struct device *dev,
1388 struct devfreq *devfreq,
1389 struct notifier_block *nb,
1392 struct devfreq_notifier_devres *ptr;
1395 ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
1400 ret = devfreq_register_notifier(devfreq, nb, list);
1406 ptr->devfreq = devfreq;
1409 devres_add(dev, ptr);
1413 EXPORT_SYMBOL(devm_devfreq_register_notifier);
1416 * devm_devfreq_unregister_notifier()
1417 - Resource-managed devfreq_unregister_notifier()
1418 * @dev: The devfreq user device. (parent of devfreq)
1419 * @devfreq: The devfreq object.
1420 * @nb: The notifier block to be unregistered.
1421 * @list: DEVFREQ_TRANSITION_NOTIFIER.
1423 void devm_devfreq_unregister_notifier(struct device *dev,
1424 struct devfreq *devfreq,
1425 struct notifier_block *nb,
1428 WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
1429 devm_devfreq_dev_match, devfreq));
1431 EXPORT_SYMBOL(devm_devfreq_unregister_notifier);
1433 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1434 MODULE_DESCRIPTION("devfreq class support");
1435 MODULE_LICENSE("GPL");