Commit | Line | Data |
---|---|---|
a3c98b8b MH |
1 | /* |
2 | * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework | |
3 | * for Non-CPU Devices. | |
4 | * | |
5 | * Copyright (C) 2011 Samsung Electronics | |
6 | * MyungJoo Ham <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> | |
952f6d13 | 18 | #include <linux/module.h> |
a3c98b8b | 19 | #include <linux/slab.h> |
952f6d13 | 20 | #include <linux/stat.h> |
a3c98b8b MH |
21 | #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 | ||
1a1357ea | 30 | static struct class *devfreq_class; |
a3c98b8b MH |
31 | |
32 | /* | |
7e6fdd4b RV |
33 | * devfreq core provides delayed work based load monitoring helper |
34 | * functions. Governors can use these or can implement their own | |
35 | * monitoring mechanism. | |
a3c98b8b | 36 | */ |
a3c98b8b | 37 | static struct workqueue_struct *devfreq_wq; |
a3c98b8b | 38 | |
3aa173b8 NM |
39 | /* The list of all device-devfreq governors */ |
40 | static LIST_HEAD(devfreq_governor_list); | |
a3c98b8b MH |
41 | /* The list of all device-devfreq */ |
42 | static LIST_HEAD(devfreq_list); | |
43 | static 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 | */ | |
52 | static 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 | ||
e552bbaf JL |
71 | /** |
72 | * devfreq_get_freq_level() - Lookup freq_table for the frequency | |
73 | * @devfreq: the devfreq instance | |
74 | * @freq: the target frequency | |
75 | */ | |
76 | static 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 | */ | |
92 | static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) | |
93 | { | |
3c2a0909 | 94 | int lev, prev_lev, ret = 0; |
e552bbaf JL |
95 | unsigned long cur_time; |
96 | ||
e552bbaf | 97 | cur_time = jiffies; |
3c2a0909 S |
98 | |
99 | prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); | |
100 | if (prev_lev < 0) { | |
101 | pr_err("DEVFREQ: invalid index to update status\n"); | |
102 | ret = prev_lev; | |
103 | goto out; | |
104 | } | |
105 | ||
106 | devfreq->time_in_state[prev_lev] += | |
e552bbaf | 107 | cur_time - devfreq->last_stat_updated; |
3c2a0909 S |
108 | |
109 | lev = devfreq_get_freq_level(devfreq, freq); | |
110 | if (lev < 0) { | |
111 | ret = lev; | |
112 | goto out; | |
113 | } | |
114 | ||
115 | if (lev != prev_lev) { | |
e552bbaf JL |
116 | devfreq->trans_table[(prev_lev * |
117 | devfreq->profile->max_state) + lev]++; | |
118 | devfreq->total_trans++; | |
119 | } | |
e552bbaf | 120 | |
3c2a0909 S |
121 | out: |
122 | devfreq->last_stat_updated = cur_time; | |
123 | return ret; | |
e552bbaf JL |
124 | } |
125 | ||
3aa173b8 NM |
126 | /** |
127 | * find_devfreq_governor() - find devfreq governor from name | |
128 | * @name: name of the governor | |
129 | * | |
130 | * Search the list of devfreq governors and return the matched | |
131 | * governor's pointer. devfreq_list_lock should be held by the caller. | |
132 | */ | |
133 | static struct devfreq_governor *find_devfreq_governor(const char *name) | |
134 | { | |
135 | struct devfreq_governor *tmp_governor; | |
136 | ||
137 | if (unlikely(IS_ERR_OR_NULL(name))) { | |
138 | pr_err("DEVFREQ: %s: Invalid parameters\n", __func__); | |
139 | return ERR_PTR(-EINVAL); | |
140 | } | |
141 | WARN(!mutex_is_locked(&devfreq_list_lock), | |
142 | "devfreq_list_lock must be locked."); | |
143 | ||
144 | list_for_each_entry(tmp_governor, &devfreq_governor_list, node) { | |
145 | if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN)) | |
146 | return tmp_governor; | |
147 | } | |
148 | ||
149 | return ERR_PTR(-ENODEV); | |
150 | } | |
151 | ||
7e6fdd4b RV |
152 | /* Load monitoring helper functions for governors use */ |
153 | ||
a3c98b8b MH |
154 | /** |
155 | * update_devfreq() - Reevaluate the device and configure frequency. | |
156 | * @devfreq: the devfreq instance. | |
157 | * | |
158 | * Note: Lock devfreq->lock before calling update_devfreq | |
159 | * This function is exported for governors. | |
160 | */ | |
161 | int update_devfreq(struct devfreq *devfreq) | |
162 | { | |
163 | unsigned long freq; | |
164 | int err = 0; | |
ab5f299f | 165 | u32 flags = 0; |
a3c98b8b MH |
166 | |
167 | if (!mutex_is_locked(&devfreq->lock)) { | |
168 | WARN(true, "devfreq->lock must be locked by the caller.\n"); | |
169 | return -EINVAL; | |
170 | } | |
171 | ||
1b5c1be2 NM |
172 | if (!devfreq->governor) |
173 | return -EINVAL; | |
174 | ||
a3c98b8b MH |
175 | /* Reevaluate the proper frequency */ |
176 | err = devfreq->governor->get_target_freq(devfreq, &freq); | |
177 | if (err) | |
178 | return err; | |
179 | ||
ab5f299f MH |
180 | /* |
181 | * Adjust the freuqency with user freq and QoS. | |
182 | * | |
183 | * List from the highest proiority | |
184 | * max_freq (probably called by thermal when it's too hot) | |
185 | * min_freq | |
186 | */ | |
187 | ||
188 | if (devfreq->min_freq && freq < devfreq->min_freq) { | |
189 | freq = devfreq->min_freq; | |
190 | flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */ | |
191 | } | |
192 | if (devfreq->max_freq && freq > devfreq->max_freq) { | |
193 | freq = devfreq->max_freq; | |
194 | flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */ | |
195 | } | |
196 | ||
197 | err = devfreq->profile->target(devfreq->dev.parent, &freq, flags); | |
a3c98b8b MH |
198 | if (err) |
199 | return err; | |
200 | ||
e552bbaf JL |
201 | if (devfreq->profile->freq_table) |
202 | if (devfreq_update_status(devfreq, freq)) | |
203 | dev_err(&devfreq->dev, | |
204 | "Couldn't update frequency transition information.\n"); | |
205 | ||
a3c98b8b MH |
206 | devfreq->previous_freq = freq; |
207 | return err; | |
208 | } | |
2df5021f | 209 | EXPORT_SYMBOL(update_devfreq); |
a3c98b8b | 210 | |
7e6fdd4b RV |
211 | /** |
212 | * devfreq_monitor() - Periodically poll devfreq objects. | |
213 | * @work: the work struct used to run devfreq_monitor periodically. | |
214 | * | |
215 | */ | |
216 | static void devfreq_monitor(struct work_struct *work) | |
217 | { | |
218 | int err; | |
219 | struct devfreq *devfreq = container_of(work, | |
220 | struct devfreq, work.work); | |
221 | ||
222 | mutex_lock(&devfreq->lock); | |
223 | err = update_devfreq(devfreq); | |
3c2a0909 | 224 | if (err && err != -EAGAIN) |
7e6fdd4b | 225 | dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err); |
3c2a0909 S |
226 | #ifdef CONFIG_SCHED_HMP |
227 | mod_delayed_work_on(0, devfreq_wq, &devfreq->work, | |
228 | msecs_to_jiffies(devfreq->profile->polling_ms)); | |
229 | #else | |
7e6fdd4b RV |
230 | queue_delayed_work(devfreq_wq, &devfreq->work, |
231 | msecs_to_jiffies(devfreq->profile->polling_ms)); | |
3c2a0909 | 232 | #endif |
7e6fdd4b RV |
233 | mutex_unlock(&devfreq->lock); |
234 | } | |
235 | ||
236 | /** | |
237 | * devfreq_monitor_start() - Start load monitoring of devfreq instance | |
238 | * @devfreq: the devfreq instance. | |
239 | * | |
240 | * Helper function for starting devfreq device load monitoing. By | |
241 | * default delayed work based monitoring is supported. Function | |
242 | * to be called from governor in response to DEVFREQ_GOV_START | |
243 | * event when device is added to devfreq framework. | |
244 | */ | |
245 | void devfreq_monitor_start(struct devfreq *devfreq) | |
246 | { | |
3c2a0909 | 247 | INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor); |
7e6fdd4b RV |
248 | if (devfreq->profile->polling_ms) |
249 | queue_delayed_work(devfreq_wq, &devfreq->work, | |
250 | msecs_to_jiffies(devfreq->profile->polling_ms)); | |
251 | } | |
6dcdd8e3 | 252 | EXPORT_SYMBOL(devfreq_monitor_start); |
7e6fdd4b RV |
253 | |
254 | /** | |
255 | * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance | |
256 | * @devfreq: the devfreq instance. | |
257 | * | |
258 | * Helper function to stop devfreq device load monitoing. Function | |
259 | * to be called from governor in response to DEVFREQ_GOV_STOP | |
260 | * event when device is removed from devfreq framework. | |
261 | */ | |
262 | void devfreq_monitor_stop(struct devfreq *devfreq) | |
263 | { | |
264 | cancel_delayed_work_sync(&devfreq->work); | |
265 | } | |
6dcdd8e3 | 266 | EXPORT_SYMBOL(devfreq_monitor_stop); |
7e6fdd4b RV |
267 | |
268 | /** | |
269 | * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance | |
270 | * @devfreq: the devfreq instance. | |
271 | * | |
272 | * Helper function to suspend devfreq device load monitoing. Function | |
273 | * to be called from governor in response to DEVFREQ_GOV_SUSPEND | |
274 | * event or when polling interval is set to zero. | |
275 | * | |
276 | * Note: Though this function is same as devfreq_monitor_stop(), | |
277 | * intentionally kept separate to provide hooks for collecting | |
278 | * transition statistics. | |
279 | */ | |
280 | void devfreq_monitor_suspend(struct devfreq *devfreq) | |
281 | { | |
282 | mutex_lock(&devfreq->lock); | |
283 | if (devfreq->stop_polling) { | |
284 | mutex_unlock(&devfreq->lock); | |
285 | return; | |
286 | } | |
287 | ||
288 | devfreq->stop_polling = true; | |
289 | mutex_unlock(&devfreq->lock); | |
290 | cancel_delayed_work_sync(&devfreq->work); | |
291 | } | |
6dcdd8e3 | 292 | EXPORT_SYMBOL(devfreq_monitor_suspend); |
7e6fdd4b RV |
293 | |
294 | /** | |
295 | * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance | |
296 | * @devfreq: the devfreq instance. | |
297 | * | |
298 | * Helper function to resume devfreq device load monitoing. Function | |
299 | * to be called from governor in response to DEVFREQ_GOV_RESUME | |
300 | * event or when polling interval is set to non-zero. | |
301 | */ | |
302 | void devfreq_monitor_resume(struct devfreq *devfreq) | |
303 | { | |
304 | mutex_lock(&devfreq->lock); | |
305 | if (!devfreq->stop_polling) | |
306 | goto out; | |
307 | ||
308 | if (!delayed_work_pending(&devfreq->work) && | |
309 | devfreq->profile->polling_ms) | |
310 | queue_delayed_work(devfreq_wq, &devfreq->work, | |
311 | msecs_to_jiffies(devfreq->profile->polling_ms)); | |
312 | devfreq->stop_polling = false; | |
313 | ||
314 | out: | |
315 | mutex_unlock(&devfreq->lock); | |
316 | } | |
6dcdd8e3 | 317 | EXPORT_SYMBOL(devfreq_monitor_resume); |
7e6fdd4b RV |
318 | |
319 | /** | |
320 | * devfreq_interval_update() - Update device devfreq monitoring interval | |
321 | * @devfreq: the devfreq instance. | |
322 | * @delay: new polling interval to be set. | |
323 | * | |
324 | * Helper function to set new load monitoring polling interval. Function | |
325 | * to be called from governor in response to DEVFREQ_GOV_INTERVAL event. | |
326 | */ | |
327 | void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay) | |
328 | { | |
329 | unsigned int cur_delay = devfreq->profile->polling_ms; | |
330 | unsigned int new_delay = *delay; | |
331 | ||
332 | mutex_lock(&devfreq->lock); | |
333 | devfreq->profile->polling_ms = new_delay; | |
334 | ||
335 | if (devfreq->stop_polling) | |
336 | goto out; | |
337 | ||
338 | /* if new delay is zero, stop polling */ | |
339 | if (!new_delay) { | |
340 | mutex_unlock(&devfreq->lock); | |
341 | cancel_delayed_work_sync(&devfreq->work); | |
342 | return; | |
343 | } | |
344 | ||
345 | /* if current delay is zero, start polling with new delay */ | |
346 | if (!cur_delay) { | |
347 | queue_delayed_work(devfreq_wq, &devfreq->work, | |
348 | msecs_to_jiffies(devfreq->profile->polling_ms)); | |
349 | goto out; | |
350 | } | |
351 | ||
352 | /* if current delay is greater than new delay, restart polling */ | |
353 | if (cur_delay > new_delay) { | |
354 | mutex_unlock(&devfreq->lock); | |
355 | cancel_delayed_work_sync(&devfreq->work); | |
356 | mutex_lock(&devfreq->lock); | |
357 | if (!devfreq->stop_polling) | |
358 | queue_delayed_work(devfreq_wq, &devfreq->work, | |
359 | msecs_to_jiffies(devfreq->profile->polling_ms)); | |
360 | } | |
361 | out: | |
362 | mutex_unlock(&devfreq->lock); | |
363 | } | |
6dcdd8e3 | 364 | EXPORT_SYMBOL(devfreq_interval_update); |
a3c98b8b MH |
365 | |
366 | /** | |
367 | * devfreq_notifier_call() - Notify that the device frequency requirements | |
368 | * has been changed out of devfreq framework. | |
c5b4a1c1 NM |
369 | * @nb: the notifier_block (supposed to be devfreq->nb) |
370 | * @type: not used | |
371 | * @devp: not used | |
a3c98b8b MH |
372 | * |
373 | * Called by a notifier that uses devfreq->nb. | |
374 | */ | |
375 | static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type, | |
376 | void *devp) | |
377 | { | |
378 | struct devfreq *devfreq = container_of(nb, struct devfreq, nb); | |
379 | int ret; | |
380 | ||
381 | mutex_lock(&devfreq->lock); | |
382 | ret = update_devfreq(devfreq); | |
383 | mutex_unlock(&devfreq->lock); | |
384 | ||
385 | return ret; | |
386 | } | |
387 | ||
388 | /** | |
7e6fdd4b | 389 | * _remove_devfreq() - Remove devfreq from the list and release its resources. |
a3c98b8b MH |
390 | * @devfreq: the devfreq struct |
391 | * @skip: skip calling device_unregister(). | |
a3c98b8b MH |
392 | */ |
393 | static void _remove_devfreq(struct devfreq *devfreq, bool skip) | |
394 | { | |
7e6fdd4b RV |
395 | mutex_lock(&devfreq_list_lock); |
396 | if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) { | |
397 | mutex_unlock(&devfreq_list_lock); | |
398 | dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n"); | |
a3c98b8b MH |
399 | return; |
400 | } | |
7e6fdd4b RV |
401 | list_del(&devfreq->node); |
402 | mutex_unlock(&devfreq_list_lock); | |
a3c98b8b | 403 | |
1b5c1be2 NM |
404 | if (devfreq->governor) |
405 | devfreq->governor->event_handler(devfreq, | |
406 | DEVFREQ_GOV_STOP, NULL); | |
a3c98b8b MH |
407 | |
408 | if (devfreq->profile->exit) | |
409 | devfreq->profile->exit(devfreq->dev.parent); | |
410 | ||
a3c98b8b MH |
411 | if (!skip && get_device(&devfreq->dev)) { |
412 | device_unregister(&devfreq->dev); | |
413 | put_device(&devfreq->dev); | |
414 | } | |
415 | ||
a3c98b8b | 416 | mutex_destroy(&devfreq->lock); |
a3c98b8b MH |
417 | kfree(devfreq); |
418 | } | |
419 | ||
420 | /** | |
421 | * devfreq_dev_release() - Callback for struct device to release the device. | |
422 | * @dev: the devfreq device | |
423 | * | |
424 | * This calls _remove_devfreq() if _remove_devfreq() is not called. | |
425 | * Note that devfreq_dev_release() could be called by _remove_devfreq() as | |
426 | * well as by others unregistering the device. | |
427 | */ | |
428 | static void devfreq_dev_release(struct device *dev) | |
429 | { | |
430 | struct devfreq *devfreq = to_devfreq(dev); | |
a3c98b8b | 431 | |
a3c98b8b | 432 | _remove_devfreq(devfreq, true); |
a3c98b8b MH |
433 | } |
434 | ||
435 | /** | |
436 | * devfreq_add_device() - Add devfreq feature to the device | |
437 | * @dev: the device to add devfreq feature. | |
438 | * @profile: device-specific profile to run devfreq. | |
1b5c1be2 | 439 | * @governor_name: name of the policy to choose frequency. |
a3c98b8b MH |
440 | * @data: private data for the governor. The devfreq framework does not |
441 | * touch this value. | |
442 | */ | |
443 | struct devfreq *devfreq_add_device(struct device *dev, | |
444 | struct devfreq_dev_profile *profile, | |
1b5c1be2 | 445 | const char *governor_name, |
a3c98b8b MH |
446 | void *data) |
447 | { | |
448 | struct devfreq *devfreq; | |
1b5c1be2 | 449 | struct devfreq_governor *governor; |
a3c98b8b MH |
450 | int err = 0; |
451 | ||
1b5c1be2 | 452 | if (!dev || !profile || !governor_name) { |
a3c98b8b MH |
453 | dev_err(dev, "%s: Invalid parameters.\n", __func__); |
454 | return ERR_PTR(-EINVAL); | |
455 | } | |
456 | ||
7e6fdd4b RV |
457 | mutex_lock(&devfreq_list_lock); |
458 | devfreq = find_device_devfreq(dev); | |
459 | mutex_unlock(&devfreq_list_lock); | |
460 | if (!IS_ERR(devfreq)) { | |
461 | dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__); | |
462 | err = -EINVAL; | |
463 | goto err_out; | |
a3c98b8b MH |
464 | } |
465 | ||
466 | devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL); | |
467 | if (!devfreq) { | |
468 | dev_err(dev, "%s: Unable to create devfreq for the device\n", | |
469 | __func__); | |
470 | err = -ENOMEM; | |
3f19f08a | 471 | goto err_out; |
a3c98b8b MH |
472 | } |
473 | ||
474 | mutex_init(&devfreq->lock); | |
475 | mutex_lock(&devfreq->lock); | |
476 | devfreq->dev.parent = dev; | |
477 | devfreq->dev.class = devfreq_class; | |
478 | devfreq->dev.release = devfreq_dev_release; | |
479 | devfreq->profile = profile; | |
1b5c1be2 | 480 | strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN); |
a3c98b8b MH |
481 | devfreq->previous_freq = profile->initial_freq; |
482 | devfreq->data = data; | |
a3c98b8b MH |
483 | devfreq->nb.notifier_call = devfreq_notifier_call; |
484 | ||
e552bbaf JL |
485 | devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) * |
486 | devfreq->profile->max_state * | |
487 | devfreq->profile->max_state, | |
488 | GFP_KERNEL); | |
3c2a0909 | 489 | devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned long) * |
e552bbaf JL |
490 | devfreq->profile->max_state, |
491 | GFP_KERNEL); | |
492 | devfreq->last_stat_updated = jiffies; | |
493 | ||
a3c98b8b MH |
494 | dev_set_name(&devfreq->dev, dev_name(dev)); |
495 | err = device_register(&devfreq->dev); | |
496 | if (err) { | |
497 | put_device(&devfreq->dev); | |
7e6fdd4b | 498 | mutex_unlock(&devfreq->lock); |
a3c98b8b MH |
499 | goto err_dev; |
500 | } | |
501 | ||
a3c98b8b MH |
502 | mutex_unlock(&devfreq->lock); |
503 | ||
a3c98b8b | 504 | mutex_lock(&devfreq_list_lock); |
a3c98b8b MH |
505 | list_add(&devfreq->node, &devfreq_list); |
506 | ||
1b5c1be2 NM |
507 | governor = find_devfreq_governor(devfreq->governor_name); |
508 | if (!IS_ERR(governor)) | |
509 | devfreq->governor = governor; | |
510 | if (devfreq->governor) | |
511 | err = devfreq->governor->event_handler(devfreq, | |
512 | DEVFREQ_GOV_START, NULL); | |
a3c98b8b | 513 | mutex_unlock(&devfreq_list_lock); |
7e6fdd4b RV |
514 | if (err) { |
515 | dev_err(dev, "%s: Unable to start governor for the device\n", | |
516 | __func__); | |
517 | goto err_init; | |
a3c98b8b | 518 | } |
7e6fdd4b | 519 | |
3f19f08a AL |
520 | return devfreq; |
521 | ||
a3c98b8b | 522 | err_init: |
7e6fdd4b | 523 | list_del(&devfreq->node); |
a3c98b8b MH |
524 | device_unregister(&devfreq->dev); |
525 | err_dev: | |
a3c98b8b | 526 | kfree(devfreq); |
3f19f08a AL |
527 | err_out: |
528 | return ERR_PTR(err); | |
a3c98b8b | 529 | } |
7e6fdd4b | 530 | EXPORT_SYMBOL(devfreq_add_device); |
a3c98b8b MH |
531 | |
532 | /** | |
533 | * devfreq_remove_device() - Remove devfreq feature from a device. | |
c5b4a1c1 | 534 | * @devfreq: the devfreq instance to be removed |
a3c98b8b MH |
535 | */ |
536 | int devfreq_remove_device(struct devfreq *devfreq) | |
537 | { | |
538 | if (!devfreq) | |
539 | return -EINVAL; | |
540 | ||
7e6fdd4b | 541 | _remove_devfreq(devfreq, false); |
9f3bdd4f | 542 | |
a3c98b8b MH |
543 | return 0; |
544 | } | |
7e6fdd4b | 545 | EXPORT_SYMBOL(devfreq_remove_device); |
a3c98b8b | 546 | |
206c30cf RV |
547 | /** |
548 | * devfreq_suspend_device() - Suspend devfreq of a device. | |
549 | * @devfreq: the devfreq instance to be suspended | |
550 | */ | |
551 | int devfreq_suspend_device(struct devfreq *devfreq) | |
552 | { | |
a3c98b8b MH |
553 | if (!devfreq) |
554 | return -EINVAL; | |
555 | ||
1b5c1be2 NM |
556 | if (!devfreq->governor) |
557 | return 0; | |
558 | ||
206c30cf RV |
559 | return devfreq->governor->event_handler(devfreq, |
560 | DEVFREQ_GOV_SUSPEND, NULL); | |
561 | } | |
562 | EXPORT_SYMBOL(devfreq_suspend_device); | |
563 | ||
564 | /** | |
565 | * devfreq_resume_device() - Resume devfreq of a device. | |
566 | * @devfreq: the devfreq instance to be resumed | |
567 | */ | |
568 | int devfreq_resume_device(struct devfreq *devfreq) | |
569 | { | |
570 | if (!devfreq) | |
571 | return -EINVAL; | |
572 | ||
1b5c1be2 NM |
573 | if (!devfreq->governor) |
574 | return 0; | |
575 | ||
206c30cf RV |
576 | return devfreq->governor->event_handler(devfreq, |
577 | DEVFREQ_GOV_RESUME, NULL); | |
578 | } | |
579 | EXPORT_SYMBOL(devfreq_resume_device); | |
580 | ||
3aa173b8 NM |
581 | /** |
582 | * devfreq_add_governor() - Add devfreq governor | |
583 | * @governor: the devfreq governor to be added | |
584 | */ | |
585 | int devfreq_add_governor(struct devfreq_governor *governor) | |
586 | { | |
587 | struct devfreq_governor *g; | |
1b5c1be2 | 588 | struct devfreq *devfreq; |
3aa173b8 NM |
589 | int err = 0; |
590 | ||
591 | if (!governor) { | |
592 | pr_err("%s: Invalid parameters.\n", __func__); | |
593 | return -EINVAL; | |
594 | } | |
595 | ||
596 | mutex_lock(&devfreq_list_lock); | |
597 | g = find_devfreq_governor(governor->name); | |
598 | if (!IS_ERR(g)) { | |
599 | pr_err("%s: governor %s already registered\n", __func__, | |
600 | g->name); | |
601 | err = -EINVAL; | |
602 | goto err_out; | |
603 | } | |
9f3bdd4f | 604 | |
3aa173b8 NM |
605 | list_add(&governor->node, &devfreq_governor_list); |
606 | ||
1b5c1be2 NM |
607 | list_for_each_entry(devfreq, &devfreq_list, node) { |
608 | int ret = 0; | |
609 | struct device *dev = devfreq->dev.parent; | |
610 | ||
611 | if (!strncmp(devfreq->governor_name, governor->name, | |
612 | DEVFREQ_NAME_LEN)) { | |
613 | /* The following should never occur */ | |
614 | if (devfreq->governor) { | |
615 | dev_warn(dev, | |
616 | "%s: Governor %s already present\n", | |
617 | __func__, devfreq->governor->name); | |
618 | ret = devfreq->governor->event_handler(devfreq, | |
619 | DEVFREQ_GOV_STOP, NULL); | |
620 | if (ret) { | |
621 | dev_warn(dev, | |
622 | "%s: Governor %s stop = %d\n", | |
623 | __func__, | |
624 | devfreq->governor->name, ret); | |
625 | } | |
626 | /* Fall through */ | |
627 | } | |
628 | devfreq->governor = governor; | |
629 | ret = devfreq->governor->event_handler(devfreq, | |
630 | DEVFREQ_GOV_START, NULL); | |
631 | if (ret) { | |
632 | dev_warn(dev, "%s: Governor %s start=%d\n", | |
633 | __func__, devfreq->governor->name, | |
634 | ret); | |
635 | } | |
a3c98b8b MH |
636 | } |
637 | } | |
638 | ||
3aa173b8 NM |
639 | err_out: |
640 | mutex_unlock(&devfreq_list_lock); | |
a3c98b8b | 641 | |
3aa173b8 NM |
642 | return err; |
643 | } | |
644 | EXPORT_SYMBOL(devfreq_add_governor); | |
a3c98b8b | 645 | |
3aa173b8 NM |
646 | /** |
647 | * devfreq_remove_device() - Remove devfreq feature from a device. | |
648 | * @governor: the devfreq governor to be removed | |
649 | */ | |
650 | int devfreq_remove_governor(struct devfreq_governor *governor) | |
651 | { | |
652 | struct devfreq_governor *g; | |
1b5c1be2 | 653 | struct devfreq *devfreq; |
3aa173b8 NM |
654 | int err = 0; |
655 | ||
656 | if (!governor) { | |
657 | pr_err("%s: Invalid parameters.\n", __func__); | |
658 | return -EINVAL; | |
659 | } | |
660 | ||
661 | mutex_lock(&devfreq_list_lock); | |
662 | g = find_devfreq_governor(governor->name); | |
663 | if (IS_ERR(g)) { | |
664 | pr_err("%s: governor %s not registered\n", __func__, | |
b9e1c8e8 | 665 | governor->name); |
f9c08e2a | 666 | err = PTR_ERR(g); |
3aa173b8 NM |
667 | goto err_out; |
668 | } | |
1b5c1be2 NM |
669 | list_for_each_entry(devfreq, &devfreq_list, node) { |
670 | int ret; | |
671 | struct device *dev = devfreq->dev.parent; | |
672 | ||
673 | if (!strncmp(devfreq->governor_name, governor->name, | |
674 | DEVFREQ_NAME_LEN)) { | |
675 | /* we should have a devfreq governor! */ | |
676 | if (!devfreq->governor) { | |
677 | dev_warn(dev, "%s: Governor %s NOT present\n", | |
678 | __func__, governor->name); | |
679 | continue; | |
680 | /* Fall through */ | |
681 | } | |
682 | ret = devfreq->governor->event_handler(devfreq, | |
683 | DEVFREQ_GOV_STOP, NULL); | |
684 | if (ret) { | |
685 | dev_warn(dev, "%s: Governor %s stop=%d\n", | |
686 | __func__, devfreq->governor->name, | |
687 | ret); | |
688 | } | |
689 | devfreq->governor = NULL; | |
690 | } | |
691 | } | |
3aa173b8 NM |
692 | |
693 | list_del(&governor->node); | |
694 | err_out: | |
695 | mutex_unlock(&devfreq_list_lock); | |
696 | ||
697 | return err; | |
a3c98b8b | 698 | } |
3aa173b8 | 699 | EXPORT_SYMBOL(devfreq_remove_governor); |
a3c98b8b | 700 | |
9005b650 MH |
701 | static ssize_t show_governor(struct device *dev, |
702 | struct device_attribute *attr, char *buf) | |
703 | { | |
1b5c1be2 NM |
704 | if (!to_devfreq(dev)->governor) |
705 | return -EINVAL; | |
706 | ||
9005b650 MH |
707 | return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name); |
708 | } | |
709 | ||
0359d1af NM |
710 | static ssize_t store_governor(struct device *dev, struct device_attribute *attr, |
711 | const char *buf, size_t count) | |
712 | { | |
713 | struct devfreq *df = to_devfreq(dev); | |
714 | int ret; | |
715 | char str_governor[DEVFREQ_NAME_LEN + 1]; | |
716 | struct devfreq_governor *governor; | |
717 | ||
718 | ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor); | |
719 | if (ret != 1) | |
720 | return -EINVAL; | |
721 | ||
722 | mutex_lock(&devfreq_list_lock); | |
723 | governor = find_devfreq_governor(str_governor); | |
724 | if (IS_ERR(governor)) { | |
725 | ret = PTR_ERR(governor); | |
726 | goto out; | |
727 | } | |
728 | if (df->governor == governor) | |
729 | goto out; | |
730 | ||
731 | if (df->governor) { | |
732 | ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL); | |
733 | if (ret) { | |
734 | dev_warn(dev, "%s: Governor %s not stopped(%d)\n", | |
735 | __func__, df->governor->name, ret); | |
736 | goto out; | |
737 | } | |
738 | } | |
739 | df->governor = governor; | |
740 | strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN); | |
741 | ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL); | |
742 | if (ret) | |
743 | dev_warn(dev, "%s: Governor %s not started(%d)\n", | |
744 | __func__, df->governor->name, ret); | |
745 | out: | |
746 | mutex_unlock(&devfreq_list_lock); | |
747 | ||
748 | if (!ret) | |
749 | ret = count; | |
750 | return ret; | |
751 | } | |
50a5b33e NM |
752 | static ssize_t show_available_governors(struct device *d, |
753 | struct device_attribute *attr, | |
754 | char *buf) | |
755 | { | |
756 | struct devfreq_governor *tmp_governor; | |
757 | ssize_t count = 0; | |
758 | ||
759 | mutex_lock(&devfreq_list_lock); | |
760 | list_for_each_entry(tmp_governor, &devfreq_governor_list, node) | |
761 | count += scnprintf(&buf[count], (PAGE_SIZE - count - 2), | |
762 | "%s ", tmp_governor->name); | |
763 | mutex_unlock(&devfreq_list_lock); | |
764 | ||
765 | /* Truncate the trailing space */ | |
766 | if (count) | |
767 | count--; | |
768 | ||
769 | count += sprintf(&buf[count], "\n"); | |
770 | ||
771 | return count; | |
772 | } | |
0359d1af | 773 | |
9005b650 MH |
774 | static ssize_t show_freq(struct device *dev, |
775 | struct device_attribute *attr, char *buf) | |
7f98a905 RV |
776 | { |
777 | unsigned long freq; | |
778 | struct devfreq *devfreq = to_devfreq(dev); | |
779 | ||
780 | if (devfreq->profile->get_cur_freq && | |
781 | !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq)) | |
782 | return sprintf(buf, "%lu\n", freq); | |
783 | ||
784 | return sprintf(buf, "%lu\n", devfreq->previous_freq); | |
785 | } | |
786 | ||
787 | static ssize_t show_target_freq(struct device *dev, | |
788 | struct device_attribute *attr, char *buf) | |
9005b650 MH |
789 | { |
790 | return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq); | |
791 | } | |
792 | ||
793 | static ssize_t show_polling_interval(struct device *dev, | |
794 | struct device_attribute *attr, char *buf) | |
795 | { | |
796 | return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms); | |
797 | } | |
798 | ||
799 | static ssize_t store_polling_interval(struct device *dev, | |
800 | struct device_attribute *attr, | |
801 | const char *buf, size_t count) | |
802 | { | |
803 | struct devfreq *df = to_devfreq(dev); | |
804 | unsigned int value; | |
805 | int ret; | |
806 | ||
1b5c1be2 NM |
807 | if (!df->governor) |
808 | return -EINVAL; | |
809 | ||
9005b650 MH |
810 | ret = sscanf(buf, "%u", &value); |
811 | if (ret != 1) | |
12e26265 | 812 | return -EINVAL; |
9005b650 | 813 | |
7e6fdd4b | 814 | df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value); |
9005b650 MH |
815 | ret = count; |
816 | ||
9005b650 MH |
817 | return ret; |
818 | } | |
819 | ||
6530b9de MH |
820 | static ssize_t store_min_freq(struct device *dev, struct device_attribute *attr, |
821 | const char *buf, size_t count) | |
822 | { | |
823 | struct devfreq *df = to_devfreq(dev); | |
824 | unsigned long value; | |
825 | int ret; | |
826 | unsigned long max; | |
827 | ||
828 | ret = sscanf(buf, "%lu", &value); | |
829 | if (ret != 1) | |
12e26265 | 830 | return -EINVAL; |
6530b9de MH |
831 | |
832 | mutex_lock(&df->lock); | |
833 | max = df->max_freq; | |
834 | if (value && max && value > max) { | |
835 | ret = -EINVAL; | |
836 | goto unlock; | |
837 | } | |
838 | ||
839 | df->min_freq = value; | |
840 | update_devfreq(df); | |
841 | ret = count; | |
842 | unlock: | |
843 | mutex_unlock(&df->lock); | |
6530b9de MH |
844 | return ret; |
845 | } | |
846 | ||
847 | static ssize_t show_min_freq(struct device *dev, struct device_attribute *attr, | |
848 | char *buf) | |
849 | { | |
850 | return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq); | |
851 | } | |
852 | ||
853 | static ssize_t store_max_freq(struct device *dev, struct device_attribute *attr, | |
854 | const char *buf, size_t count) | |
855 | { | |
856 | struct devfreq *df = to_devfreq(dev); | |
857 | unsigned long value; | |
858 | int ret; | |
859 | unsigned long min; | |
860 | ||
861 | ret = sscanf(buf, "%lu", &value); | |
862 | if (ret != 1) | |
12e26265 | 863 | return -EINVAL; |
6530b9de MH |
864 | |
865 | mutex_lock(&df->lock); | |
866 | min = df->min_freq; | |
867 | if (value && min && value < min) { | |
868 | ret = -EINVAL; | |
869 | goto unlock; | |
870 | } | |
871 | ||
872 | df->max_freq = value; | |
873 | update_devfreq(df); | |
874 | ret = count; | |
875 | unlock: | |
876 | mutex_unlock(&df->lock); | |
6530b9de MH |
877 | return ret; |
878 | } | |
879 | ||
880 | static ssize_t show_max_freq(struct device *dev, struct device_attribute *attr, | |
881 | char *buf) | |
882 | { | |
883 | return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq); | |
884 | } | |
885 | ||
d287de85 NM |
886 | static ssize_t show_available_freqs(struct device *d, |
887 | struct device_attribute *attr, | |
888 | char *buf) | |
889 | { | |
890 | struct devfreq *df = to_devfreq(d); | |
891 | struct device *dev = df->dev.parent; | |
892 | struct opp *opp; | |
893 | ssize_t count = 0; | |
894 | unsigned long freq = 0; | |
895 | ||
896 | rcu_read_lock(); | |
897 | do { | |
898 | opp = opp_find_freq_ceil(dev, &freq); | |
899 | if (IS_ERR(opp)) | |
900 | break; | |
901 | ||
902 | count += scnprintf(&buf[count], (PAGE_SIZE - count - 2), | |
903 | "%lu ", freq); | |
904 | freq++; | |
905 | } while (1); | |
906 | rcu_read_unlock(); | |
907 | ||
908 | /* Truncate the trailing space */ | |
909 | if (count) | |
910 | count--; | |
911 | ||
912 | count += sprintf(&buf[count], "\n"); | |
913 | ||
914 | return count; | |
915 | } | |
916 | ||
e552bbaf JL |
917 | static ssize_t show_trans_table(struct device *dev, struct device_attribute *attr, |
918 | char *buf) | |
919 | { | |
920 | struct devfreq *devfreq = to_devfreq(dev); | |
921 | ssize_t len; | |
922 | int i, j, err; | |
923 | unsigned int max_state = devfreq->profile->max_state; | |
924 | ||
925 | err = devfreq_update_status(devfreq, devfreq->previous_freq); | |
926 | if (err) | |
927 | return 0; | |
928 | ||
929 | len = sprintf(buf, " From : To\n"); | |
930 | len += sprintf(buf + len, " :"); | |
931 | for (i = 0; i < max_state; i++) | |
932 | len += sprintf(buf + len, "%8u", | |
933 | devfreq->profile->freq_table[i]); | |
934 | ||
935 | len += sprintf(buf + len, " time(ms)\n"); | |
936 | ||
937 | for (i = 0; i < max_state; i++) { | |
938 | if (devfreq->profile->freq_table[i] | |
939 | == devfreq->previous_freq) { | |
940 | len += sprintf(buf + len, "*"); | |
941 | } else { | |
942 | len += sprintf(buf + len, " "); | |
943 | } | |
944 | len += sprintf(buf + len, "%8u:", | |
945 | devfreq->profile->freq_table[i]); | |
946 | for (j = 0; j < max_state; j++) | |
947 | len += sprintf(buf + len, "%8u", | |
948 | devfreq->trans_table[(i * max_state) + j]); | |
949 | len += sprintf(buf + len, "%10u\n", | |
950 | jiffies_to_msecs(devfreq->time_in_state[i])); | |
951 | } | |
952 | ||
953 | len += sprintf(buf + len, "Total transition : %u\n", | |
954 | devfreq->total_trans); | |
955 | return len; | |
956 | } | |
957 | ||
3c2a0909 S |
958 | static ssize_t show_time_in_state(struct device *dev, |
959 | struct device_attribute *attr, char *buf) | |
960 | { | |
961 | struct devfreq *devfreq = to_devfreq(dev); | |
962 | ssize_t len = 0; | |
963 | int i, err; | |
964 | unsigned int max_state = devfreq->profile->max_state; | |
965 | ||
966 | err = devfreq_update_status(devfreq, devfreq->previous_freq); | |
967 | if (err) | |
968 | return 0; | |
969 | ||
970 | for (i = 0; i < max_state; i++) { | |
971 | len += sprintf(buf + len, "%8u", | |
972 | devfreq->profile->freq_table[i]); | |
973 | len += sprintf(buf + len, "%10u\n", | |
974 | jiffies_to_msecs(devfreq->time_in_state[i])); | |
975 | } | |
976 | return len; | |
977 | } | |
978 | ||
9005b650 | 979 | static struct device_attribute devfreq_attrs[] = { |
0359d1af | 980 | __ATTR(governor, S_IRUGO | S_IWUSR, show_governor, store_governor), |
50a5b33e | 981 | __ATTR(available_governors, S_IRUGO, show_available_governors, NULL), |
9005b650 | 982 | __ATTR(cur_freq, S_IRUGO, show_freq, NULL), |
d287de85 | 983 | __ATTR(available_frequencies, S_IRUGO, show_available_freqs, NULL), |
7f98a905 | 984 | __ATTR(target_freq, S_IRUGO, show_target_freq, NULL), |
9005b650 MH |
985 | __ATTR(polling_interval, S_IRUGO | S_IWUSR, show_polling_interval, |
986 | store_polling_interval), | |
6530b9de MH |
987 | __ATTR(min_freq, S_IRUGO | S_IWUSR, show_min_freq, store_min_freq), |
988 | __ATTR(max_freq, S_IRUGO | S_IWUSR, show_max_freq, store_max_freq), | |
e552bbaf | 989 | __ATTR(trans_stat, S_IRUGO, show_trans_table, NULL), |
3c2a0909 | 990 | __ATTR(time_in_state_raw, S_IRUGO, show_time_in_state, NULL), |
9005b650 MH |
991 | { }, |
992 | }; | |
993 | ||
a3c98b8b MH |
994 | static int __init devfreq_init(void) |
995 | { | |
996 | devfreq_class = class_create(THIS_MODULE, "devfreq"); | |
997 | if (IS_ERR(devfreq_class)) { | |
998 | pr_err("%s: couldn't create class\n", __FILE__); | |
999 | return PTR_ERR(devfreq_class); | |
1000 | } | |
7e6fdd4b RV |
1001 | |
1002 | devfreq_wq = create_freezable_workqueue("devfreq_wq"); | |
1003 | if (IS_ERR(devfreq_wq)) { | |
1004 | class_destroy(devfreq_class); | |
1005 | pr_err("%s: couldn't create workqueue\n", __FILE__); | |
1006 | return PTR_ERR(devfreq_wq); | |
1007 | } | |
9005b650 | 1008 | devfreq_class->dev_attrs = devfreq_attrs; |
7e6fdd4b | 1009 | |
a3c98b8b MH |
1010 | return 0; |
1011 | } | |
1012 | subsys_initcall(devfreq_init); | |
1013 | ||
1014 | static void __exit devfreq_exit(void) | |
1015 | { | |
1016 | class_destroy(devfreq_class); | |
7e6fdd4b | 1017 | destroy_workqueue(devfreq_wq); |
a3c98b8b MH |
1018 | } |
1019 | module_exit(devfreq_exit); | |
1020 | ||
1021 | /* | |
1022 | * The followings are helper functions for devfreq user device drivers with | |
1023 | * OPP framework. | |
1024 | */ | |
1025 | ||
1026 | /** | |
1027 | * devfreq_recommended_opp() - Helper function to get proper OPP for the | |
1028 | * freq value given to target callback. | |
c5b4a1c1 NM |
1029 | * @dev: The devfreq user device. (parent of devfreq) |
1030 | * @freq: The frequency given to target function | |
1031 | * @flags: Flags handed from devfreq framework. | |
a3c98b8b | 1032 | * |
bcb27549 NM |
1033 | * Locking: This function must be called under rcu_read_lock(). opp is a rcu |
1034 | * protected pointer. The reason for the same is that the opp pointer which is | |
1035 | * returned will remain valid for use with opp_get_{voltage, freq} only while | |
1036 | * under the locked area. The pointer returned must be used prior to unlocking | |
1037 | * with rcu_read_unlock() to maintain the integrity of the pointer. | |
a3c98b8b | 1038 | */ |
ab5f299f MH |
1039 | struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq, |
1040 | u32 flags) | |
a3c98b8b | 1041 | { |
ab5f299f | 1042 | struct opp *opp; |
a3c98b8b | 1043 | |
ab5f299f MH |
1044 | if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) { |
1045 | /* The freq is an upper bound. opp should be lower */ | |
a3c98b8b | 1046 | opp = opp_find_freq_floor(dev, freq); |
ab5f299f MH |
1047 | |
1048 | /* If not available, use the closest opp */ | |
0779726c | 1049 | if (opp == ERR_PTR(-ERANGE)) |
ab5f299f MH |
1050 | opp = opp_find_freq_ceil(dev, freq); |
1051 | } else { | |
1052 | /* The freq is an lower bound. opp should be higher */ | |
1053 | opp = opp_find_freq_ceil(dev, freq); | |
1054 | ||
1055 | /* If not available, use the closest opp */ | |
0779726c | 1056 | if (opp == ERR_PTR(-ERANGE)) |
ab5f299f MH |
1057 | opp = opp_find_freq_floor(dev, freq); |
1058 | } | |
1059 | ||
a3c98b8b MH |
1060 | return opp; |
1061 | } | |
1062 | ||
1063 | /** | |
1064 | * devfreq_register_opp_notifier() - Helper function to get devfreq notified | |
1065 | * for any changes in the OPP availability | |
1066 | * changes | |
c5b4a1c1 NM |
1067 | * @dev: The devfreq user device. (parent of devfreq) |
1068 | * @devfreq: The devfreq object. | |
a3c98b8b MH |
1069 | */ |
1070 | int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq) | |
1071 | { | |
389baed0 MH |
1072 | struct srcu_notifier_head *nh; |
1073 | int ret = 0; | |
a3c98b8b | 1074 | |
389baed0 MH |
1075 | rcu_read_lock(); |
1076 | nh = opp_get_notifier(dev); | |
a3c98b8b | 1077 | if (IS_ERR(nh)) |
389baed0 MH |
1078 | ret = PTR_ERR(nh); |
1079 | rcu_read_unlock(); | |
1080 | if (!ret) | |
1081 | ret = srcu_notifier_chain_register(nh, &devfreq->nb); | |
1082 | ||
1083 | return ret; | |
a3c98b8b MH |
1084 | } |
1085 | ||
1086 | /** | |
1087 | * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq | |
1088 | * notified for any changes in the OPP | |
1089 | * availability changes anymore. | |
c5b4a1c1 NM |
1090 | * @dev: The devfreq user device. (parent of devfreq) |
1091 | * @devfreq: The devfreq object. | |
a3c98b8b MH |
1092 | * |
1093 | * At exit() callback of devfreq_dev_profile, this must be included if | |
1094 | * devfreq_recommended_opp is used. | |
1095 | */ | |
1096 | int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq) | |
1097 | { | |
389baed0 MH |
1098 | struct srcu_notifier_head *nh; |
1099 | int ret = 0; | |
a3c98b8b | 1100 | |
389baed0 MH |
1101 | rcu_read_lock(); |
1102 | nh = opp_get_notifier(dev); | |
a3c98b8b | 1103 | if (IS_ERR(nh)) |
389baed0 MH |
1104 | ret = PTR_ERR(nh); |
1105 | rcu_read_unlock(); | |
1106 | if (!ret) | |
1107 | ret = srcu_notifier_chain_unregister(nh, &devfreq->nb); | |
1108 | ||
1109 | return ret; | |
a3c98b8b MH |
1110 | } |
1111 | ||
1112 | MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); | |
1113 | MODULE_DESCRIPTION("devfreq class support"); | |
1114 | MODULE_LICENSE("GPL"); |