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MyungJoo Hama3c98b82011-10-02 00:19:15 +02001/*
2 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
3 * for Non-CPU Devices.
4 *
5 * Copyright (C) 2011 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/errno.h>
16#include <linux/err.h>
17#include <linux/init.h>
MyungJoo Ham952f6d12011-11-10 10:16:23 +010018#include <linux/module.h>
MyungJoo Hama3c98b82011-10-02 00:19:15 +020019#include <linux/slab.h>
MyungJoo Ham952f6d12011-11-10 10:16:23 +010020#include <linux/stat.h>
MyungJoo Hama3c98b82011-10-02 00:19:15 +020021#include <linux/opp.h>
22#include <linux/devfreq.h>
23#include <linux/workqueue.h>
24#include <linux/platform_device.h>
25#include <linux/list.h>
26#include <linux/printk.h>
27#include <linux/hrtimer.h>
28#include "governor.h"
29
Nishanth Menon1a1357e2012-10-26 01:50:53 +020030static struct class *devfreq_class;
MyungJoo Hama3c98b82011-10-02 00:19:15 +020031
32/*
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +020033 * devfreq core provides delayed work based load monitoring helper
34 * functions. Governors can use these or can implement their own
35 * monitoring mechanism.
MyungJoo Hama3c98b82011-10-02 00:19:15 +020036 */
MyungJoo Hama3c98b82011-10-02 00:19:15 +020037static struct workqueue_struct *devfreq_wq;
MyungJoo Hama3c98b82011-10-02 00:19:15 +020038
Nishanth Menon3aa173b2012-10-29 15:01:43 -050039/* The list of all device-devfreq governors */
40static LIST_HEAD(devfreq_governor_list);
MyungJoo Hama3c98b82011-10-02 00:19:15 +020041/* The list of all device-devfreq */
42static LIST_HEAD(devfreq_list);
43static DEFINE_MUTEX(devfreq_list_lock);
44
45/**
46 * find_device_devfreq() - find devfreq struct using device pointer
47 * @dev: device pointer used to lookup device devfreq.
48 *
49 * Search the list of device devfreqs and return the matched device's
50 * devfreq info. devfreq_list_lock should be held by the caller.
51 */
52static struct devfreq *find_device_devfreq(struct device *dev)
53{
54 struct devfreq *tmp_devfreq;
55
56 if (unlikely(IS_ERR_OR_NULL(dev))) {
57 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
58 return ERR_PTR(-EINVAL);
59 }
60 WARN(!mutex_is_locked(&devfreq_list_lock),
61 "devfreq_list_lock must be locked.");
62
63 list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
64 if (tmp_devfreq->dev.parent == dev)
65 return tmp_devfreq;
66 }
67
68 return ERR_PTR(-ENODEV);
69}
70
71/**
Jonghwa Leee552bba2012-08-23 20:00:46 +090072 * devfreq_get_freq_level() - Lookup freq_table for the frequency
73 * @devfreq: the devfreq instance
74 * @freq: the target frequency
75 */
76static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
77{
78 int lev;
79
80 for (lev = 0; lev < devfreq->profile->max_state; lev++)
81 if (freq == devfreq->profile->freq_table[lev])
82 return lev;
83
84 return -EINVAL;
85}
86
87/**
88 * devfreq_update_status() - Update statistics of devfreq behavior
89 * @devfreq: the devfreq instance
90 * @freq: the update target frequency
91 */
92static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
93{
94 int lev, prev_lev;
95 unsigned long cur_time;
96
97 lev = devfreq_get_freq_level(devfreq, freq);
98 if (lev < 0)
99 return lev;
100
101 cur_time = jiffies;
102 devfreq->time_in_state[lev] +=
103 cur_time - devfreq->last_stat_updated;
104 if (freq != devfreq->previous_freq) {
105 prev_lev = devfreq_get_freq_level(devfreq,
106 devfreq->previous_freq);
107 devfreq->trans_table[(prev_lev *
108 devfreq->profile->max_state) + lev]++;
109 devfreq->total_trans++;
110 }
111 devfreq->last_stat_updated = cur_time;
112
113 return 0;
114}
115
Nishanth Menon3aa173b2012-10-29 15:01:43 -0500116/**
117 * find_devfreq_governor() - find devfreq governor from name
118 * @name: name of the governor
119 *
120 * Search the list of devfreq governors and return the matched
121 * governor's pointer. devfreq_list_lock should be held by the caller.
122 */
123static struct devfreq_governor *find_devfreq_governor(const char *name)
124{
125 struct devfreq_governor *tmp_governor;
126
127 if (unlikely(IS_ERR_OR_NULL(name))) {
128 pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
129 return ERR_PTR(-EINVAL);
130 }
131 WARN(!mutex_is_locked(&devfreq_list_lock),
132 "devfreq_list_lock must be locked.");
133
134 list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
135 if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
136 return tmp_governor;
137 }
138
139 return ERR_PTR(-ENODEV);
140}
141
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200142/* Load monitoring helper functions for governors use */
143
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200144/**
145 * update_devfreq() - Reevaluate the device and configure frequency.
146 * @devfreq: the devfreq instance.
147 *
148 * Note: Lock devfreq->lock before calling update_devfreq
149 * This function is exported for governors.
150 */
151int update_devfreq(struct devfreq *devfreq)
152{
153 unsigned long freq;
154 int err = 0;
MyungJoo Hamab5f2992012-03-16 21:54:53 +0100155 u32 flags = 0;
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200156
157 if (!mutex_is_locked(&devfreq->lock)) {
158 WARN(true, "devfreq->lock must be locked by the caller.\n");
159 return -EINVAL;
160 }
161
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500162 if (!devfreq->governor)
163 return -EINVAL;
164
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200165 /* Reevaluate the proper frequency */
166 err = devfreq->governor->get_target_freq(devfreq, &freq);
167 if (err)
168 return err;
169
MyungJoo Hamab5f2992012-03-16 21:54:53 +0100170 /*
171 * Adjust the freuqency with user freq and QoS.
172 *
173 * List from the highest proiority
174 * max_freq (probably called by thermal when it's too hot)
175 * min_freq
176 */
177
178 if (devfreq->min_freq && freq < devfreq->min_freq) {
179 freq = devfreq->min_freq;
180 flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
181 }
182 if (devfreq->max_freq && freq > devfreq->max_freq) {
183 freq = devfreq->max_freq;
184 flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
185 }
186
187 err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200188 if (err)
189 return err;
190
Jonghwa Leee552bba2012-08-23 20:00:46 +0900191 if (devfreq->profile->freq_table)
192 if (devfreq_update_status(devfreq, freq))
193 dev_err(&devfreq->dev,
194 "Couldn't update frequency transition information.\n");
195
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200196 devfreq->previous_freq = freq;
197 return err;
198}
Nishanth Menon2df50212012-10-29 15:01:42 -0500199EXPORT_SYMBOL(update_devfreq);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200200
201/**
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200202 * devfreq_monitor() - Periodically poll devfreq objects.
203 * @work: the work struct used to run devfreq_monitor periodically.
204 *
205 */
206static void devfreq_monitor(struct work_struct *work)
207{
208 int err;
209 struct devfreq *devfreq = container_of(work,
210 struct devfreq, work.work);
211
212 mutex_lock(&devfreq->lock);
213 err = update_devfreq(devfreq);
214 if (err)
215 dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
216
217 queue_delayed_work(devfreq_wq, &devfreq->work,
218 msecs_to_jiffies(devfreq->profile->polling_ms));
219 mutex_unlock(&devfreq->lock);
220}
221
222/**
223 * devfreq_monitor_start() - Start load monitoring of devfreq instance
224 * @devfreq: the devfreq instance.
225 *
226 * Helper function for starting devfreq device load monitoing. By
227 * default delayed work based monitoring is supported. Function
228 * to be called from governor in response to DEVFREQ_GOV_START
229 * event when device is added to devfreq framework.
230 */
231void devfreq_monitor_start(struct devfreq *devfreq)
232{
233 INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
234 if (devfreq->profile->polling_ms)
235 queue_delayed_work(devfreq_wq, &devfreq->work,
236 msecs_to_jiffies(devfreq->profile->polling_ms));
237}
MyungJoo Ham6dcdd8e2012-11-28 20:29:17 +0100238EXPORT_SYMBOL(devfreq_monitor_start);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200239
240/**
241 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
242 * @devfreq: the devfreq instance.
243 *
244 * Helper function to stop devfreq device load monitoing. Function
245 * to be called from governor in response to DEVFREQ_GOV_STOP
246 * event when device is removed from devfreq framework.
247 */
248void devfreq_monitor_stop(struct devfreq *devfreq)
249{
250 cancel_delayed_work_sync(&devfreq->work);
251}
MyungJoo Ham6dcdd8e2012-11-28 20:29:17 +0100252EXPORT_SYMBOL(devfreq_monitor_stop);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200253
254/**
255 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
256 * @devfreq: the devfreq instance.
257 *
258 * Helper function to suspend devfreq device load monitoing. Function
259 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
260 * event or when polling interval is set to zero.
261 *
262 * Note: Though this function is same as devfreq_monitor_stop(),
263 * intentionally kept separate to provide hooks for collecting
264 * transition statistics.
265 */
266void devfreq_monitor_suspend(struct devfreq *devfreq)
267{
268 mutex_lock(&devfreq->lock);
269 if (devfreq->stop_polling) {
270 mutex_unlock(&devfreq->lock);
271 return;
272 }
273
Rajagopal Venkat39688ce2013-01-08 11:20:39 +0530274 devfreq_update_status(devfreq, devfreq->previous_freq);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200275 devfreq->stop_polling = true;
276 mutex_unlock(&devfreq->lock);
277 cancel_delayed_work_sync(&devfreq->work);
278}
MyungJoo Ham6dcdd8e2012-11-28 20:29:17 +0100279EXPORT_SYMBOL(devfreq_monitor_suspend);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200280
281/**
282 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
283 * @devfreq: the devfreq instance.
284 *
285 * Helper function to resume devfreq device load monitoing. Function
286 * to be called from governor in response to DEVFREQ_GOV_RESUME
287 * event or when polling interval is set to non-zero.
288 */
289void devfreq_monitor_resume(struct devfreq *devfreq)
290{
Rajagopal Venkat39688ce2013-01-08 11:20:39 +0530291 unsigned long freq;
292
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200293 mutex_lock(&devfreq->lock);
294 if (!devfreq->stop_polling)
295 goto out;
296
297 if (!delayed_work_pending(&devfreq->work) &&
298 devfreq->profile->polling_ms)
299 queue_delayed_work(devfreq_wq, &devfreq->work,
300 msecs_to_jiffies(devfreq->profile->polling_ms));
Rajagopal Venkat39688ce2013-01-08 11:20:39 +0530301
302 devfreq->last_stat_updated = jiffies;
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200303 devfreq->stop_polling = false;
304
Rajagopal Venkat39688ce2013-01-08 11:20:39 +0530305 if (devfreq->profile->get_cur_freq &&
306 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
307 devfreq->previous_freq = freq;
308
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200309out:
310 mutex_unlock(&devfreq->lock);
311}
MyungJoo Ham6dcdd8e2012-11-28 20:29:17 +0100312EXPORT_SYMBOL(devfreq_monitor_resume);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200313
314/**
315 * devfreq_interval_update() - Update device devfreq monitoring interval
316 * @devfreq: the devfreq instance.
317 * @delay: new polling interval to be set.
318 *
319 * Helper function to set new load monitoring polling interval. Function
320 * to be called from governor in response to DEVFREQ_GOV_INTERVAL event.
321 */
322void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
323{
324 unsigned int cur_delay = devfreq->profile->polling_ms;
325 unsigned int new_delay = *delay;
326
327 mutex_lock(&devfreq->lock);
328 devfreq->profile->polling_ms = new_delay;
329
330 if (devfreq->stop_polling)
331 goto out;
332
333 /* if new delay is zero, stop polling */
334 if (!new_delay) {
335 mutex_unlock(&devfreq->lock);
336 cancel_delayed_work_sync(&devfreq->work);
337 return;
338 }
339
340 /* if current delay is zero, start polling with new delay */
341 if (!cur_delay) {
342 queue_delayed_work(devfreq_wq, &devfreq->work,
343 msecs_to_jiffies(devfreq->profile->polling_ms));
344 goto out;
345 }
346
347 /* if current delay is greater than new delay, restart polling */
348 if (cur_delay > new_delay) {
349 mutex_unlock(&devfreq->lock);
350 cancel_delayed_work_sync(&devfreq->work);
351 mutex_lock(&devfreq->lock);
352 if (!devfreq->stop_polling)
353 queue_delayed_work(devfreq_wq, &devfreq->work,
354 msecs_to_jiffies(devfreq->profile->polling_ms));
355 }
356out:
357 mutex_unlock(&devfreq->lock);
358}
MyungJoo Ham6dcdd8e2012-11-28 20:29:17 +0100359EXPORT_SYMBOL(devfreq_interval_update);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200360
361/**
362 * devfreq_notifier_call() - Notify that the device frequency requirements
363 * has been changed out of devfreq framework.
Nishanth Menonc5b4a1c12012-10-26 01:50:35 +0200364 * @nb: the notifier_block (supposed to be devfreq->nb)
365 * @type: not used
366 * @devp: not used
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200367 *
368 * Called by a notifier that uses devfreq->nb.
369 */
370static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
371 void *devp)
372{
373 struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
374 int ret;
375
376 mutex_lock(&devfreq->lock);
377 ret = update_devfreq(devfreq);
378 mutex_unlock(&devfreq->lock);
379
380 return ret;
381}
382
383/**
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200384 * _remove_devfreq() - Remove devfreq from the list and release its resources.
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200385 * @devfreq: the devfreq struct
386 * @skip: skip calling device_unregister().
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200387 */
388static void _remove_devfreq(struct devfreq *devfreq, bool skip)
389{
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200390 mutex_lock(&devfreq_list_lock);
391 if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
392 mutex_unlock(&devfreq_list_lock);
393 dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n");
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200394 return;
395 }
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200396 list_del(&devfreq->node);
397 mutex_unlock(&devfreq_list_lock);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200398
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500399 if (devfreq->governor)
400 devfreq->governor->event_handler(devfreq,
401 DEVFREQ_GOV_STOP, NULL);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200402
403 if (devfreq->profile->exit)
404 devfreq->profile->exit(devfreq->dev.parent);
405
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200406 if (!skip && get_device(&devfreq->dev)) {
407 device_unregister(&devfreq->dev);
408 put_device(&devfreq->dev);
409 }
410
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200411 mutex_destroy(&devfreq->lock);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200412 kfree(devfreq);
413}
414
415/**
416 * devfreq_dev_release() - Callback for struct device to release the device.
417 * @dev: the devfreq device
418 *
419 * This calls _remove_devfreq() if _remove_devfreq() is not called.
420 * Note that devfreq_dev_release() could be called by _remove_devfreq() as
421 * well as by others unregistering the device.
422 */
423static void devfreq_dev_release(struct device *dev)
424{
425 struct devfreq *devfreq = to_devfreq(dev);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200426
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200427 _remove_devfreq(devfreq, true);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200428}
429
430/**
431 * devfreq_add_device() - Add devfreq feature to the device
432 * @dev: the device to add devfreq feature.
433 * @profile: device-specific profile to run devfreq.
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500434 * @governor_name: name of the policy to choose frequency.
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200435 * @data: private data for the governor. The devfreq framework does not
436 * touch this value.
437 */
438struct devfreq *devfreq_add_device(struct device *dev,
439 struct devfreq_dev_profile *profile,
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500440 const char *governor_name,
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200441 void *data)
442{
443 struct devfreq *devfreq;
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500444 struct devfreq_governor *governor;
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200445 int err = 0;
446
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500447 if (!dev || !profile || !governor_name) {
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200448 dev_err(dev, "%s: Invalid parameters.\n", __func__);
449 return ERR_PTR(-EINVAL);
450 }
451
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200452 mutex_lock(&devfreq_list_lock);
453 devfreq = find_device_devfreq(dev);
454 mutex_unlock(&devfreq_list_lock);
455 if (!IS_ERR(devfreq)) {
456 dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
457 err = -EINVAL;
458 goto err_out;
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200459 }
460
461 devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
462 if (!devfreq) {
463 dev_err(dev, "%s: Unable to create devfreq for the device\n",
464 __func__);
465 err = -ENOMEM;
Axel Lin3f19f082011-11-15 21:59:09 +0100466 goto err_out;
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200467 }
468
469 mutex_init(&devfreq->lock);
470 mutex_lock(&devfreq->lock);
471 devfreq->dev.parent = dev;
472 devfreq->dev.class = devfreq_class;
473 devfreq->dev.release = devfreq_dev_release;
474 devfreq->profile = profile;
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500475 strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200476 devfreq->previous_freq = profile->initial_freq;
477 devfreq->data = data;
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200478 devfreq->nb.notifier_call = devfreq_notifier_call;
479
Jonghwa Leee552bba2012-08-23 20:00:46 +0900480 devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) *
481 devfreq->profile->max_state *
482 devfreq->profile->max_state,
483 GFP_KERNEL);
484 devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned int) *
485 devfreq->profile->max_state,
486 GFP_KERNEL);
487 devfreq->last_stat_updated = jiffies;
488
Kees Cook02aa2a32013-07-03 15:04:56 -0700489 dev_set_name(&devfreq->dev, "%s", dev_name(dev));
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200490 err = device_register(&devfreq->dev);
491 if (err) {
492 put_device(&devfreq->dev);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200493 mutex_unlock(&devfreq->lock);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200494 goto err_dev;
495 }
496
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200497 mutex_unlock(&devfreq->lock);
498
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200499 mutex_lock(&devfreq_list_lock);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200500 list_add(&devfreq->node, &devfreq_list);
501
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500502 governor = find_devfreq_governor(devfreq->governor_name);
503 if (!IS_ERR(governor))
504 devfreq->governor = governor;
505 if (devfreq->governor)
506 err = devfreq->governor->event_handler(devfreq,
507 DEVFREQ_GOV_START, NULL);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200508 mutex_unlock(&devfreq_list_lock);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200509 if (err) {
510 dev_err(dev, "%s: Unable to start governor for the device\n",
511 __func__);
512 goto err_init;
513 }
514
Axel Lin3f19f082011-11-15 21:59:09 +0100515 return devfreq;
516
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200517err_init:
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200518 list_del(&devfreq->node);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200519 device_unregister(&devfreq->dev);
520err_dev:
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200521 kfree(devfreq);
Axel Lin3f19f082011-11-15 21:59:09 +0100522err_out:
523 return ERR_PTR(err);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200524}
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200525EXPORT_SYMBOL(devfreq_add_device);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200526
527/**
528 * devfreq_remove_device() - Remove devfreq feature from a device.
Nishanth Menonc5b4a1c12012-10-26 01:50:35 +0200529 * @devfreq: the devfreq instance to be removed
MyungJoo Hamde9c7392013-02-05 18:40:17 +0900530 *
531 * The opposite of devfreq_add_device().
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200532 */
533int devfreq_remove_device(struct devfreq *devfreq)
534{
535 if (!devfreq)
536 return -EINVAL;
537
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200538 _remove_devfreq(devfreq, false);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200539
540 return 0;
541}
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200542EXPORT_SYMBOL(devfreq_remove_device);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200543
Rajagopal Venkat206c30c2012-10-26 01:50:18 +0200544/**
545 * devfreq_suspend_device() - Suspend devfreq of a device.
546 * @devfreq: the devfreq instance to be suspended
MyungJoo Hamde9c7392013-02-05 18:40:17 +0900547 *
548 * This function is intended to be called by the pm callbacks
549 * (e.g., runtime_suspend, suspend) of the device driver that
550 * holds the devfreq.
Rajagopal Venkat206c30c2012-10-26 01:50:18 +0200551 */
552int devfreq_suspend_device(struct devfreq *devfreq)
553{
554 if (!devfreq)
555 return -EINVAL;
556
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500557 if (!devfreq->governor)
558 return 0;
559
Rajagopal Venkat206c30c2012-10-26 01:50:18 +0200560 return devfreq->governor->event_handler(devfreq,
561 DEVFREQ_GOV_SUSPEND, NULL);
562}
563EXPORT_SYMBOL(devfreq_suspend_device);
564
565/**
566 * devfreq_resume_device() - Resume devfreq of a device.
567 * @devfreq: the devfreq instance to be resumed
MyungJoo Hamde9c7392013-02-05 18:40:17 +0900568 *
569 * This function is intended to be called by the pm callbacks
570 * (e.g., runtime_resume, resume) of the device driver that
571 * holds the devfreq.
Rajagopal Venkat206c30c2012-10-26 01:50:18 +0200572 */
573int devfreq_resume_device(struct devfreq *devfreq)
574{
575 if (!devfreq)
576 return -EINVAL;
577
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500578 if (!devfreq->governor)
579 return 0;
580
Rajagopal Venkat206c30c2012-10-26 01:50:18 +0200581 return devfreq->governor->event_handler(devfreq,
582 DEVFREQ_GOV_RESUME, NULL);
583}
584EXPORT_SYMBOL(devfreq_resume_device);
585
Nishanth Menon3aa173b2012-10-29 15:01:43 -0500586/**
587 * devfreq_add_governor() - Add devfreq governor
588 * @governor: the devfreq governor to be added
589 */
590int devfreq_add_governor(struct devfreq_governor *governor)
591{
592 struct devfreq_governor *g;
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500593 struct devfreq *devfreq;
Nishanth Menon3aa173b2012-10-29 15:01:43 -0500594 int err = 0;
595
596 if (!governor) {
597 pr_err("%s: Invalid parameters.\n", __func__);
598 return -EINVAL;
599 }
600
601 mutex_lock(&devfreq_list_lock);
602 g = find_devfreq_governor(governor->name);
603 if (!IS_ERR(g)) {
604 pr_err("%s: governor %s already registered\n", __func__,
605 g->name);
606 err = -EINVAL;
607 goto err_out;
608 }
609
610 list_add(&governor->node, &devfreq_governor_list);
611
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500612 list_for_each_entry(devfreq, &devfreq_list, node) {
613 int ret = 0;
614 struct device *dev = devfreq->dev.parent;
615
616 if (!strncmp(devfreq->governor_name, governor->name,
617 DEVFREQ_NAME_LEN)) {
618 /* The following should never occur */
619 if (devfreq->governor) {
620 dev_warn(dev,
621 "%s: Governor %s already present\n",
622 __func__, devfreq->governor->name);
623 ret = devfreq->governor->event_handler(devfreq,
624 DEVFREQ_GOV_STOP, NULL);
625 if (ret) {
626 dev_warn(dev,
627 "%s: Governor %s stop = %d\n",
628 __func__,
629 devfreq->governor->name, ret);
630 }
631 /* Fall through */
632 }
633 devfreq->governor = governor;
634 ret = devfreq->governor->event_handler(devfreq,
635 DEVFREQ_GOV_START, NULL);
636 if (ret) {
637 dev_warn(dev, "%s: Governor %s start=%d\n",
638 __func__, devfreq->governor->name,
639 ret);
640 }
641 }
642 }
643
Nishanth Menon3aa173b2012-10-29 15:01:43 -0500644err_out:
645 mutex_unlock(&devfreq_list_lock);
646
647 return err;
648}
649EXPORT_SYMBOL(devfreq_add_governor);
650
651/**
652 * devfreq_remove_device() - Remove devfreq feature from a device.
653 * @governor: the devfreq governor to be removed
654 */
655int devfreq_remove_governor(struct devfreq_governor *governor)
656{
657 struct devfreq_governor *g;
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500658 struct devfreq *devfreq;
Nishanth Menon3aa173b2012-10-29 15:01:43 -0500659 int err = 0;
660
661 if (!governor) {
662 pr_err("%s: Invalid parameters.\n", __func__);
663 return -EINVAL;
664 }
665
666 mutex_lock(&devfreq_list_lock);
667 g = find_devfreq_governor(governor->name);
668 if (IS_ERR(g)) {
669 pr_err("%s: governor %s not registered\n", __func__,
Sachin Kamatb9e1c8e2012-11-21 10:36:13 +0530670 governor->name);
Sachin Kamatf9c08e22012-11-21 10:36:14 +0530671 err = PTR_ERR(g);
Nishanth Menon3aa173b2012-10-29 15:01:43 -0500672 goto err_out;
673 }
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500674 list_for_each_entry(devfreq, &devfreq_list, node) {
675 int ret;
676 struct device *dev = devfreq->dev.parent;
677
678 if (!strncmp(devfreq->governor_name, governor->name,
679 DEVFREQ_NAME_LEN)) {
680 /* we should have a devfreq governor! */
681 if (!devfreq->governor) {
682 dev_warn(dev, "%s: Governor %s NOT present\n",
683 __func__, governor->name);
684 continue;
685 /* Fall through */
686 }
687 ret = devfreq->governor->event_handler(devfreq,
688 DEVFREQ_GOV_STOP, NULL);
689 if (ret) {
690 dev_warn(dev, "%s: Governor %s stop=%d\n",
691 __func__, devfreq->governor->name,
692 ret);
693 }
694 devfreq->governor = NULL;
695 }
696 }
Nishanth Menon3aa173b2012-10-29 15:01:43 -0500697
698 list_del(&governor->node);
699err_out:
700 mutex_unlock(&devfreq_list_lock);
701
702 return err;
703}
704EXPORT_SYMBOL(devfreq_remove_governor);
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200705
MyungJoo Ham9005b652011-10-02 00:19:28 +0200706static ssize_t show_governor(struct device *dev,
707 struct device_attribute *attr, char *buf)
708{
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500709 if (!to_devfreq(dev)->governor)
710 return -EINVAL;
711
MyungJoo Ham9005b652011-10-02 00:19:28 +0200712 return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name);
713}
714
Nishanth Menon0359d1a2012-10-29 15:01:47 -0500715static ssize_t store_governor(struct device *dev, struct device_attribute *attr,
716 const char *buf, size_t count)
717{
718 struct devfreq *df = to_devfreq(dev);
719 int ret;
720 char str_governor[DEVFREQ_NAME_LEN + 1];
721 struct devfreq_governor *governor;
722
723 ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
724 if (ret != 1)
725 return -EINVAL;
726
727 mutex_lock(&devfreq_list_lock);
728 governor = find_devfreq_governor(str_governor);
729 if (IS_ERR(governor)) {
730 ret = PTR_ERR(governor);
731 goto out;
732 }
733 if (df->governor == governor)
734 goto out;
735
736 if (df->governor) {
737 ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
738 if (ret) {
739 dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
740 __func__, df->governor->name, ret);
741 goto out;
742 }
743 }
744 df->governor = governor;
745 strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
746 ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
747 if (ret)
748 dev_warn(dev, "%s: Governor %s not started(%d)\n",
749 __func__, df->governor->name, ret);
750out:
751 mutex_unlock(&devfreq_list_lock);
752
753 if (!ret)
754 ret = count;
755 return ret;
756}
Nishanth Menon50a5b332012-10-29 15:01:48 -0500757static ssize_t show_available_governors(struct device *d,
758 struct device_attribute *attr,
759 char *buf)
760{
761 struct devfreq_governor *tmp_governor;
762 ssize_t count = 0;
763
764 mutex_lock(&devfreq_list_lock);
765 list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
766 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
767 "%s ", tmp_governor->name);
768 mutex_unlock(&devfreq_list_lock);
769
770 /* Truncate the trailing space */
771 if (count)
772 count--;
773
774 count += sprintf(&buf[count], "\n");
775
776 return count;
777}
Nishanth Menon0359d1a2012-10-29 15:01:47 -0500778
MyungJoo Ham9005b652011-10-02 00:19:28 +0200779static ssize_t show_freq(struct device *dev,
780 struct device_attribute *attr, char *buf)
781{
Rajagopal Venkat7f98a902012-10-26 01:50:26 +0200782 unsigned long freq;
783 struct devfreq *devfreq = to_devfreq(dev);
784
785 if (devfreq->profile->get_cur_freq &&
786 !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
787 return sprintf(buf, "%lu\n", freq);
788
789 return sprintf(buf, "%lu\n", devfreq->previous_freq);
790}
791
792static ssize_t show_target_freq(struct device *dev,
793 struct device_attribute *attr, char *buf)
794{
MyungJoo Ham9005b652011-10-02 00:19:28 +0200795 return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
796}
797
798static ssize_t show_polling_interval(struct device *dev,
799 struct device_attribute *attr, char *buf)
800{
801 return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
802}
803
804static ssize_t store_polling_interval(struct device *dev,
805 struct device_attribute *attr,
806 const char *buf, size_t count)
807{
808 struct devfreq *df = to_devfreq(dev);
809 unsigned int value;
810 int ret;
811
Nishanth Menon1b5c1be2012-10-29 15:01:45 -0500812 if (!df->governor)
813 return -EINVAL;
814
MyungJoo Ham9005b652011-10-02 00:19:28 +0200815 ret = sscanf(buf, "%u", &value);
816 if (ret != 1)
Nishanth Menon12e26262012-10-26 01:50:43 +0200817 return -EINVAL;
MyungJoo Ham9005b652011-10-02 00:19:28 +0200818
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200819 df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value);
MyungJoo Ham9005b652011-10-02 00:19:28 +0200820 ret = count;
821
MyungJoo Ham9005b652011-10-02 00:19:28 +0200822 return ret;
823}
824
MyungJoo Ham6530b9de2011-12-09 16:42:19 +0900825static ssize_t store_min_freq(struct device *dev, struct device_attribute *attr,
826 const char *buf, size_t count)
827{
828 struct devfreq *df = to_devfreq(dev);
829 unsigned long value;
830 int ret;
831 unsigned long max;
832
833 ret = sscanf(buf, "%lu", &value);
834 if (ret != 1)
Nishanth Menon12e26262012-10-26 01:50:43 +0200835 return -EINVAL;
MyungJoo Ham6530b9de2011-12-09 16:42:19 +0900836
837 mutex_lock(&df->lock);
838 max = df->max_freq;
839 if (value && max && value > max) {
840 ret = -EINVAL;
841 goto unlock;
842 }
843
844 df->min_freq = value;
845 update_devfreq(df);
846 ret = count;
847unlock:
848 mutex_unlock(&df->lock);
MyungJoo Ham6530b9de2011-12-09 16:42:19 +0900849 return ret;
850}
851
852static ssize_t show_min_freq(struct device *dev, struct device_attribute *attr,
853 char *buf)
854{
855 return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq);
856}
857
858static ssize_t store_max_freq(struct device *dev, struct device_attribute *attr,
859 const char *buf, size_t count)
860{
861 struct devfreq *df = to_devfreq(dev);
862 unsigned long value;
863 int ret;
864 unsigned long min;
865
866 ret = sscanf(buf, "%lu", &value);
867 if (ret != 1)
Nishanth Menon12e26262012-10-26 01:50:43 +0200868 return -EINVAL;
MyungJoo Ham6530b9de2011-12-09 16:42:19 +0900869
870 mutex_lock(&df->lock);
871 min = df->min_freq;
872 if (value && min && value < min) {
873 ret = -EINVAL;
874 goto unlock;
875 }
876
877 df->max_freq = value;
878 update_devfreq(df);
879 ret = count;
880unlock:
881 mutex_unlock(&df->lock);
MyungJoo Ham6530b9de2011-12-09 16:42:19 +0900882 return ret;
883}
884
885static ssize_t show_max_freq(struct device *dev, struct device_attribute *attr,
886 char *buf)
887{
888 return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
889}
890
Nishanth Menond287de82012-10-25 19:48:59 -0500891static ssize_t show_available_freqs(struct device *d,
892 struct device_attribute *attr,
893 char *buf)
894{
895 struct devfreq *df = to_devfreq(d);
896 struct device *dev = df->dev.parent;
897 struct opp *opp;
898 ssize_t count = 0;
899 unsigned long freq = 0;
900
901 rcu_read_lock();
902 do {
903 opp = opp_find_freq_ceil(dev, &freq);
904 if (IS_ERR(opp))
905 break;
906
907 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
908 "%lu ", freq);
909 freq++;
910 } while (1);
911 rcu_read_unlock();
912
913 /* Truncate the trailing space */
914 if (count)
915 count--;
916
917 count += sprintf(&buf[count], "\n");
918
919 return count;
920}
921
Jonghwa Leee552bba2012-08-23 20:00:46 +0900922static ssize_t show_trans_table(struct device *dev, struct device_attribute *attr,
923 char *buf)
924{
925 struct devfreq *devfreq = to_devfreq(dev);
926 ssize_t len;
Rajagopal Venkat39688ce2013-01-08 11:20:39 +0530927 int i, j;
Jonghwa Leee552bba2012-08-23 20:00:46 +0900928 unsigned int max_state = devfreq->profile->max_state;
929
Rajagopal Venkat39688ce2013-01-08 11:20:39 +0530930 if (!devfreq->stop_polling &&
931 devfreq_update_status(devfreq, devfreq->previous_freq))
Jonghwa Leee552bba2012-08-23 20:00:46 +0900932 return 0;
933
934 len = sprintf(buf, " From : To\n");
935 len += sprintf(buf + len, " :");
936 for (i = 0; i < max_state; i++)
937 len += sprintf(buf + len, "%8u",
938 devfreq->profile->freq_table[i]);
939
940 len += sprintf(buf + len, " time(ms)\n");
941
942 for (i = 0; i < max_state; i++) {
943 if (devfreq->profile->freq_table[i]
944 == devfreq->previous_freq) {
945 len += sprintf(buf + len, "*");
946 } else {
947 len += sprintf(buf + len, " ");
948 }
949 len += sprintf(buf + len, "%8u:",
950 devfreq->profile->freq_table[i]);
951 for (j = 0; j < max_state; j++)
952 len += sprintf(buf + len, "%8u",
953 devfreq->trans_table[(i * max_state) + j]);
954 len += sprintf(buf + len, "%10u\n",
955 jiffies_to_msecs(devfreq->time_in_state[i]));
956 }
957
958 len += sprintf(buf + len, "Total transition : %u\n",
959 devfreq->total_trans);
960 return len;
961}
962
MyungJoo Ham9005b652011-10-02 00:19:28 +0200963static struct device_attribute devfreq_attrs[] = {
Nishanth Menon0359d1a2012-10-29 15:01:47 -0500964 __ATTR(governor, S_IRUGO | S_IWUSR, show_governor, store_governor),
Nishanth Menon50a5b332012-10-29 15:01:48 -0500965 __ATTR(available_governors, S_IRUGO, show_available_governors, NULL),
MyungJoo Ham9005b652011-10-02 00:19:28 +0200966 __ATTR(cur_freq, S_IRUGO, show_freq, NULL),
Nishanth Menond287de82012-10-25 19:48:59 -0500967 __ATTR(available_frequencies, S_IRUGO, show_available_freqs, NULL),
Rajagopal Venkat7f98a902012-10-26 01:50:26 +0200968 __ATTR(target_freq, S_IRUGO, show_target_freq, NULL),
MyungJoo Ham9005b652011-10-02 00:19:28 +0200969 __ATTR(polling_interval, S_IRUGO | S_IWUSR, show_polling_interval,
970 store_polling_interval),
MyungJoo Ham6530b9de2011-12-09 16:42:19 +0900971 __ATTR(min_freq, S_IRUGO | S_IWUSR, show_min_freq, store_min_freq),
972 __ATTR(max_freq, S_IRUGO | S_IWUSR, show_max_freq, store_max_freq),
Jonghwa Leee552bba2012-08-23 20:00:46 +0900973 __ATTR(trans_stat, S_IRUGO, show_trans_table, NULL),
MyungJoo Ham9005b652011-10-02 00:19:28 +0200974 { },
975};
976
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200977static int __init devfreq_init(void)
978{
979 devfreq_class = class_create(THIS_MODULE, "devfreq");
980 if (IS_ERR(devfreq_class)) {
981 pr_err("%s: couldn't create class\n", __FILE__);
982 return PTR_ERR(devfreq_class);
983 }
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200984
985 devfreq_wq = create_freezable_workqueue("devfreq_wq");
986 if (IS_ERR(devfreq_wq)) {
987 class_destroy(devfreq_class);
988 pr_err("%s: couldn't create workqueue\n", __FILE__);
989 return PTR_ERR(devfreq_wq);
990 }
MyungJoo Ham9005b652011-10-02 00:19:28 +0200991 devfreq_class->dev_attrs = devfreq_attrs;
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +0200992
MyungJoo Hama3c98b82011-10-02 00:19:15 +0200993 return 0;
994}
995subsys_initcall(devfreq_init);
996
997static void __exit devfreq_exit(void)
998{
999 class_destroy(devfreq_class);
Rajagopal Venkat7e6fdd42012-10-26 01:50:09 +02001000 destroy_workqueue(devfreq_wq);
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001001}
1002module_exit(devfreq_exit);
1003
1004/*
1005 * The followings are helper functions for devfreq user device drivers with
1006 * OPP framework.
1007 */
1008
1009/**
1010 * devfreq_recommended_opp() - Helper function to get proper OPP for the
1011 * freq value given to target callback.
Nishanth Menonc5b4a1c12012-10-26 01:50:35 +02001012 * @dev: The devfreq user device. (parent of devfreq)
1013 * @freq: The frequency given to target function
1014 * @flags: Flags handed from devfreq framework.
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001015 *
Nishanth Menonbcb27542013-01-18 19:52:34 +00001016 * Locking: This function must be called under rcu_read_lock(). opp is a rcu
1017 * protected pointer. The reason for the same is that the opp pointer which is
1018 * returned will remain valid for use with opp_get_{voltage, freq} only while
1019 * under the locked area. The pointer returned must be used prior to unlocking
1020 * with rcu_read_unlock() to maintain the integrity of the pointer.
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001021 */
MyungJoo Hamab5f2992012-03-16 21:54:53 +01001022struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq,
1023 u32 flags)
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001024{
MyungJoo Hamab5f2992012-03-16 21:54:53 +01001025 struct opp *opp;
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001026
MyungJoo Hamab5f2992012-03-16 21:54:53 +01001027 if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
1028 /* The freq is an upper bound. opp should be lower */
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001029 opp = opp_find_freq_floor(dev, freq);
MyungJoo Hamab5f2992012-03-16 21:54:53 +01001030
1031 /* If not available, use the closest opp */
Nishanth Menon07797262012-10-24 22:00:12 +02001032 if (opp == ERR_PTR(-ERANGE))
MyungJoo Hamab5f2992012-03-16 21:54:53 +01001033 opp = opp_find_freq_ceil(dev, freq);
1034 } else {
1035 /* The freq is an lower bound. opp should be higher */
1036 opp = opp_find_freq_ceil(dev, freq);
1037
1038 /* If not available, use the closest opp */
Nishanth Menon07797262012-10-24 22:00:12 +02001039 if (opp == ERR_PTR(-ERANGE))
MyungJoo Hamab5f2992012-03-16 21:54:53 +01001040 opp = opp_find_freq_floor(dev, freq);
1041 }
1042
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001043 return opp;
1044}
1045
1046/**
1047 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
1048 * for any changes in the OPP availability
1049 * changes
Nishanth Menonc5b4a1c12012-10-26 01:50:35 +02001050 * @dev: The devfreq user device. (parent of devfreq)
1051 * @devfreq: The devfreq object.
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001052 */
1053int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
1054{
MyungJoo Ham389baed2012-11-21 19:04:51 +09001055 struct srcu_notifier_head *nh;
1056 int ret = 0;
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001057
MyungJoo Ham389baed2012-11-21 19:04:51 +09001058 rcu_read_lock();
1059 nh = opp_get_notifier(dev);
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001060 if (IS_ERR(nh))
MyungJoo Ham389baed2012-11-21 19:04:51 +09001061 ret = PTR_ERR(nh);
1062 rcu_read_unlock();
1063 if (!ret)
1064 ret = srcu_notifier_chain_register(nh, &devfreq->nb);
1065
1066 return ret;
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001067}
1068
1069/**
1070 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
1071 * notified for any changes in the OPP
1072 * availability changes anymore.
Nishanth Menonc5b4a1c12012-10-26 01:50:35 +02001073 * @dev: The devfreq user device. (parent of devfreq)
1074 * @devfreq: The devfreq object.
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001075 *
1076 * At exit() callback of devfreq_dev_profile, this must be included if
1077 * devfreq_recommended_opp is used.
1078 */
1079int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
1080{
MyungJoo Ham389baed2012-11-21 19:04:51 +09001081 struct srcu_notifier_head *nh;
1082 int ret = 0;
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001083
MyungJoo Ham389baed2012-11-21 19:04:51 +09001084 rcu_read_lock();
1085 nh = opp_get_notifier(dev);
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001086 if (IS_ERR(nh))
MyungJoo Ham389baed2012-11-21 19:04:51 +09001087 ret = PTR_ERR(nh);
1088 rcu_read_unlock();
1089 if (!ret)
1090 ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
1091
1092 return ret;
MyungJoo Hama3c98b82011-10-02 00:19:15 +02001093}
1094
1095MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1096MODULE_DESCRIPTION("devfreq class support");
1097MODULE_LICENSE("GPL");