blob: 9955ad7e786e5a3eabcff56ebc8516100db46928 [file] [log] [blame]
Mike Turquetteb24764902012-03-15 23:11:19 -07001/*
2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Standard functionality for the common clock API. See Documentation/clk.txt
10 */
11
12#include <linux/clk-private.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/spinlock.h>
16#include <linux/err.h>
17#include <linux/list.h>
18#include <linux/slab.h>
Grant Likely766e6a42012-04-09 14:50:06 -050019#include <linux/of.h>
Stephen Boyd46c87732012-09-24 13:38:04 -070020#include <linux/device.h>
Mike Turquetteb24764902012-03-15 23:11:19 -070021
22static DEFINE_SPINLOCK(enable_lock);
23static DEFINE_MUTEX(prepare_lock);
24
25static HLIST_HEAD(clk_root_list);
26static HLIST_HEAD(clk_orphan_list);
27static LIST_HEAD(clk_notifier_list);
28
29/*** debugfs support ***/
30
31#ifdef CONFIG_COMMON_CLK_DEBUG
32#include <linux/debugfs.h>
33
34static struct dentry *rootdir;
35static struct dentry *orphandir;
36static int inited = 0;
37
38/* caller must hold prepare_lock */
39static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
40{
41 struct dentry *d;
42 int ret = -ENOMEM;
43
44 if (!clk || !pdentry) {
45 ret = -EINVAL;
46 goto out;
47 }
48
49 d = debugfs_create_dir(clk->name, pdentry);
50 if (!d)
51 goto out;
52
53 clk->dentry = d;
54
55 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
56 (u32 *)&clk->rate);
57 if (!d)
58 goto err_out;
59
60 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
61 (u32 *)&clk->flags);
62 if (!d)
63 goto err_out;
64
65 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
66 (u32 *)&clk->prepare_count);
67 if (!d)
68 goto err_out;
69
70 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
71 (u32 *)&clk->enable_count);
72 if (!d)
73 goto err_out;
74
75 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
76 (u32 *)&clk->notifier_count);
77 if (!d)
78 goto err_out;
79
80 ret = 0;
81 goto out;
82
83err_out:
84 debugfs_remove(clk->dentry);
85out:
86 return ret;
87}
88
89/* caller must hold prepare_lock */
90static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
91{
92 struct clk *child;
93 struct hlist_node *tmp;
94 int ret = -EINVAL;;
95
96 if (!clk || !pdentry)
97 goto out;
98
99 ret = clk_debug_create_one(clk, pdentry);
100
101 if (ret)
102 goto out;
103
104 hlist_for_each_entry(child, tmp, &clk->children, child_node)
105 clk_debug_create_subtree(child, clk->dentry);
106
107 ret = 0;
108out:
109 return ret;
110}
111
112/**
113 * clk_debug_register - add a clk node to the debugfs clk tree
114 * @clk: the clk being added to the debugfs clk tree
115 *
116 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
117 * initialized. Otherwise it bails out early since the debugfs clk tree
118 * will be created lazily by clk_debug_init as part of a late_initcall.
119 *
120 * Caller must hold prepare_lock. Only clk_init calls this function (so
121 * far) so this is taken care.
122 */
123static int clk_debug_register(struct clk *clk)
124{
125 struct clk *parent;
126 struct dentry *pdentry;
127 int ret = 0;
128
129 if (!inited)
130 goto out;
131
132 parent = clk->parent;
133
134 /*
135 * Check to see if a clk is a root clk. Also check that it is
136 * safe to add this clk to debugfs
137 */
138 if (!parent)
139 if (clk->flags & CLK_IS_ROOT)
140 pdentry = rootdir;
141 else
142 pdentry = orphandir;
143 else
144 if (parent->dentry)
145 pdentry = parent->dentry;
146 else
147 goto out;
148
149 ret = clk_debug_create_subtree(clk, pdentry);
150
151out:
152 return ret;
153}
154
155/**
156 * clk_debug_init - lazily create the debugfs clk tree visualization
157 *
158 * clks are often initialized very early during boot before memory can
159 * be dynamically allocated and well before debugfs is setup.
160 * clk_debug_init walks the clk tree hierarchy while holding
161 * prepare_lock and creates the topology as part of a late_initcall,
162 * thus insuring that clks initialized very early will still be
163 * represented in the debugfs clk tree. This function should only be
164 * called once at boot-time, and all other clks added dynamically will
165 * be done so with clk_debug_register.
166 */
167static int __init clk_debug_init(void)
168{
169 struct clk *clk;
170 struct hlist_node *tmp;
171
172 rootdir = debugfs_create_dir("clk", NULL);
173
174 if (!rootdir)
175 return -ENOMEM;
176
177 orphandir = debugfs_create_dir("orphans", rootdir);
178
179 if (!orphandir)
180 return -ENOMEM;
181
182 mutex_lock(&prepare_lock);
183
184 hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
185 clk_debug_create_subtree(clk, rootdir);
186
187 hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
188 clk_debug_create_subtree(clk, orphandir);
189
190 inited = 1;
191
192 mutex_unlock(&prepare_lock);
193
194 return 0;
195}
196late_initcall(clk_debug_init);
197#else
198static inline int clk_debug_register(struct clk *clk) { return 0; }
Mike Turquette70d347e2012-03-26 11:53:47 -0700199#endif
Mike Turquetteb24764902012-03-15 23:11:19 -0700200
Mike Turquetteb24764902012-03-15 23:11:19 -0700201/* caller must hold prepare_lock */
202static void clk_disable_unused_subtree(struct clk *clk)
203{
204 struct clk *child;
205 struct hlist_node *tmp;
206 unsigned long flags;
207
208 if (!clk)
209 goto out;
210
211 hlist_for_each_entry(child, tmp, &clk->children, child_node)
212 clk_disable_unused_subtree(child);
213
214 spin_lock_irqsave(&enable_lock, flags);
215
216 if (clk->enable_count)
217 goto unlock_out;
218
219 if (clk->flags & CLK_IGNORE_UNUSED)
220 goto unlock_out;
221
222 if (__clk_is_enabled(clk) && clk->ops->disable)
223 clk->ops->disable(clk->hw);
224
225unlock_out:
226 spin_unlock_irqrestore(&enable_lock, flags);
227
228out:
229 return;
230}
231
232static int clk_disable_unused(void)
233{
234 struct clk *clk;
235 struct hlist_node *tmp;
236
237 mutex_lock(&prepare_lock);
238
239 hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
240 clk_disable_unused_subtree(clk);
241
242 hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
243 clk_disable_unused_subtree(clk);
244
245 mutex_unlock(&prepare_lock);
246
247 return 0;
248}
249late_initcall(clk_disable_unused);
Mike Turquetteb24764902012-03-15 23:11:19 -0700250
251/*** helper functions ***/
252
253inline const char *__clk_get_name(struct clk *clk)
254{
255 return !clk ? NULL : clk->name;
256}
257
258inline struct clk_hw *__clk_get_hw(struct clk *clk)
259{
260 return !clk ? NULL : clk->hw;
261}
262
263inline u8 __clk_get_num_parents(struct clk *clk)
264{
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700265 return !clk ? 0 : clk->num_parents;
Mike Turquetteb24764902012-03-15 23:11:19 -0700266}
267
268inline struct clk *__clk_get_parent(struct clk *clk)
269{
270 return !clk ? NULL : clk->parent;
271}
272
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700273inline unsigned int __clk_get_enable_count(struct clk *clk)
Mike Turquetteb24764902012-03-15 23:11:19 -0700274{
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700275 return !clk ? 0 : clk->enable_count;
Mike Turquetteb24764902012-03-15 23:11:19 -0700276}
277
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700278inline unsigned int __clk_get_prepare_count(struct clk *clk)
Mike Turquetteb24764902012-03-15 23:11:19 -0700279{
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700280 return !clk ? 0 : clk->prepare_count;
Mike Turquetteb24764902012-03-15 23:11:19 -0700281}
282
283unsigned long __clk_get_rate(struct clk *clk)
284{
285 unsigned long ret;
286
287 if (!clk) {
Rajendra Nayak34e44fe2012-03-26 19:01:48 +0530288 ret = 0;
Mike Turquetteb24764902012-03-15 23:11:19 -0700289 goto out;
290 }
291
292 ret = clk->rate;
293
294 if (clk->flags & CLK_IS_ROOT)
295 goto out;
296
297 if (!clk->parent)
Rajendra Nayak34e44fe2012-03-26 19:01:48 +0530298 ret = 0;
Mike Turquetteb24764902012-03-15 23:11:19 -0700299
300out:
301 return ret;
302}
303
304inline unsigned long __clk_get_flags(struct clk *clk)
305{
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700306 return !clk ? 0 : clk->flags;
Mike Turquetteb24764902012-03-15 23:11:19 -0700307}
308
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700309bool __clk_is_enabled(struct clk *clk)
Mike Turquetteb24764902012-03-15 23:11:19 -0700310{
311 int ret;
312
313 if (!clk)
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700314 return false;
Mike Turquetteb24764902012-03-15 23:11:19 -0700315
316 /*
317 * .is_enabled is only mandatory for clocks that gate
318 * fall back to software usage counter if .is_enabled is missing
319 */
320 if (!clk->ops->is_enabled) {
321 ret = clk->enable_count ? 1 : 0;
322 goto out;
323 }
324
325 ret = clk->ops->is_enabled(clk->hw);
326out:
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700327 return !!ret;
Mike Turquetteb24764902012-03-15 23:11:19 -0700328}
329
330static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
331{
332 struct clk *child;
333 struct clk *ret;
334 struct hlist_node *tmp;
335
336 if (!strcmp(clk->name, name))
337 return clk;
338
339 hlist_for_each_entry(child, tmp, &clk->children, child_node) {
340 ret = __clk_lookup_subtree(name, child);
341 if (ret)
342 return ret;
343 }
344
345 return NULL;
346}
347
348struct clk *__clk_lookup(const char *name)
349{
350 struct clk *root_clk;
351 struct clk *ret;
352 struct hlist_node *tmp;
353
354 if (!name)
355 return NULL;
356
357 /* search the 'proper' clk tree first */
358 hlist_for_each_entry(root_clk, tmp, &clk_root_list, child_node) {
359 ret = __clk_lookup_subtree(name, root_clk);
360 if (ret)
361 return ret;
362 }
363
364 /* if not found, then search the orphan tree */
365 hlist_for_each_entry(root_clk, tmp, &clk_orphan_list, child_node) {
366 ret = __clk_lookup_subtree(name, root_clk);
367 if (ret)
368 return ret;
369 }
370
371 return NULL;
372}
373
374/*** clk api ***/
375
376void __clk_unprepare(struct clk *clk)
377{
378 if (!clk)
379 return;
380
381 if (WARN_ON(clk->prepare_count == 0))
382 return;
383
384 if (--clk->prepare_count > 0)
385 return;
386
387 WARN_ON(clk->enable_count > 0);
388
389 if (clk->ops->unprepare)
390 clk->ops->unprepare(clk->hw);
391
392 __clk_unprepare(clk->parent);
393}
394
395/**
396 * clk_unprepare - undo preparation of a clock source
397 * @clk: the clk being unprepare
398 *
399 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
400 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
401 * if the operation may sleep. One example is a clk which is accessed over
402 * I2c. In the complex case a clk gate operation may require a fast and a slow
403 * part. It is this reason that clk_unprepare and clk_disable are not mutually
404 * exclusive. In fact clk_disable must be called before clk_unprepare.
405 */
406void clk_unprepare(struct clk *clk)
407{
408 mutex_lock(&prepare_lock);
409 __clk_unprepare(clk);
410 mutex_unlock(&prepare_lock);
411}
412EXPORT_SYMBOL_GPL(clk_unprepare);
413
414int __clk_prepare(struct clk *clk)
415{
416 int ret = 0;
417
418 if (!clk)
419 return 0;
420
421 if (clk->prepare_count == 0) {
422 ret = __clk_prepare(clk->parent);
423 if (ret)
424 return ret;
425
426 if (clk->ops->prepare) {
427 ret = clk->ops->prepare(clk->hw);
428 if (ret) {
429 __clk_unprepare(clk->parent);
430 return ret;
431 }
432 }
433 }
434
435 clk->prepare_count++;
436
437 return 0;
438}
439
440/**
441 * clk_prepare - prepare a clock source
442 * @clk: the clk being prepared
443 *
444 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
445 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
446 * operation may sleep. One example is a clk which is accessed over I2c. In
447 * the complex case a clk ungate operation may require a fast and a slow part.
448 * It is this reason that clk_prepare and clk_enable are not mutually
449 * exclusive. In fact clk_prepare must be called before clk_enable.
450 * Returns 0 on success, -EERROR otherwise.
451 */
452int clk_prepare(struct clk *clk)
453{
454 int ret;
455
456 mutex_lock(&prepare_lock);
457 ret = __clk_prepare(clk);
458 mutex_unlock(&prepare_lock);
459
460 return ret;
461}
462EXPORT_SYMBOL_GPL(clk_prepare);
463
464static void __clk_disable(struct clk *clk)
465{
466 if (!clk)
467 return;
468
Fengguang Wue47c6a32012-07-30 14:39:54 -0700469 if (WARN_ON(IS_ERR(clk)))
470 return;
471
Mike Turquetteb24764902012-03-15 23:11:19 -0700472 if (WARN_ON(clk->enable_count == 0))
473 return;
474
475 if (--clk->enable_count > 0)
476 return;
477
478 if (clk->ops->disable)
479 clk->ops->disable(clk->hw);
480
481 __clk_disable(clk->parent);
482}
483
484/**
485 * clk_disable - gate a clock
486 * @clk: the clk being gated
487 *
488 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
489 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
490 * clk if the operation is fast and will never sleep. One example is a
491 * SoC-internal clk which is controlled via simple register writes. In the
492 * complex case a clk gate operation may require a fast and a slow part. It is
493 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
494 * In fact clk_disable must be called before clk_unprepare.
495 */
496void clk_disable(struct clk *clk)
497{
498 unsigned long flags;
499
500 spin_lock_irqsave(&enable_lock, flags);
501 __clk_disable(clk);
502 spin_unlock_irqrestore(&enable_lock, flags);
503}
504EXPORT_SYMBOL_GPL(clk_disable);
505
506static int __clk_enable(struct clk *clk)
507{
508 int ret = 0;
509
510 if (!clk)
511 return 0;
512
513 if (WARN_ON(clk->prepare_count == 0))
514 return -ESHUTDOWN;
515
516 if (clk->enable_count == 0) {
517 ret = __clk_enable(clk->parent);
518
519 if (ret)
520 return ret;
521
522 if (clk->ops->enable) {
523 ret = clk->ops->enable(clk->hw);
524 if (ret) {
525 __clk_disable(clk->parent);
526 return ret;
527 }
528 }
529 }
530
531 clk->enable_count++;
532 return 0;
533}
534
535/**
536 * clk_enable - ungate a clock
537 * @clk: the clk being ungated
538 *
539 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
540 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
541 * if the operation will never sleep. One example is a SoC-internal clk which
542 * is controlled via simple register writes. In the complex case a clk ungate
543 * operation may require a fast and a slow part. It is this reason that
544 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
545 * must be called before clk_enable. Returns 0 on success, -EERROR
546 * otherwise.
547 */
548int clk_enable(struct clk *clk)
549{
550 unsigned long flags;
551 int ret;
552
553 spin_lock_irqsave(&enable_lock, flags);
554 ret = __clk_enable(clk);
555 spin_unlock_irqrestore(&enable_lock, flags);
556
557 return ret;
558}
559EXPORT_SYMBOL_GPL(clk_enable);
560
561/**
Mike Turquetteb24764902012-03-15 23:11:19 -0700562 * __clk_round_rate - round the given rate for a clk
563 * @clk: round the rate of this clock
564 *
565 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
566 */
567unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
568{
Shawn Guo81536e02012-04-12 20:50:17 +0800569 unsigned long parent_rate = 0;
Mike Turquetteb24764902012-03-15 23:11:19 -0700570
571 if (!clk)
Stephen Boyd2ac6b1f2012-10-03 23:38:55 -0700572 return 0;
Mike Turquetteb24764902012-03-15 23:11:19 -0700573
Shawn Guof4d8af22012-04-12 20:50:19 +0800574 if (!clk->ops->round_rate) {
575 if (clk->flags & CLK_SET_RATE_PARENT)
576 return __clk_round_rate(clk->parent, rate);
577 else
578 return clk->rate;
579 }
Mike Turquetteb24764902012-03-15 23:11:19 -0700580
Shawn Guo81536e02012-04-12 20:50:17 +0800581 if (clk->parent)
582 parent_rate = clk->parent->rate;
583
584 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
Mike Turquetteb24764902012-03-15 23:11:19 -0700585}
586
587/**
588 * clk_round_rate - round the given rate for a clk
589 * @clk: the clk for which we are rounding a rate
590 * @rate: the rate which is to be rounded
591 *
592 * Takes in a rate as input and rounds it to a rate that the clk can actually
593 * use which is then returned. If clk doesn't support round_rate operation
594 * then the parent rate is returned.
595 */
596long clk_round_rate(struct clk *clk, unsigned long rate)
597{
598 unsigned long ret;
599
600 mutex_lock(&prepare_lock);
601 ret = __clk_round_rate(clk, rate);
602 mutex_unlock(&prepare_lock);
603
604 return ret;
605}
606EXPORT_SYMBOL_GPL(clk_round_rate);
607
608/**
609 * __clk_notify - call clk notifier chain
610 * @clk: struct clk * that is changing rate
611 * @msg: clk notifier type (see include/linux/clk.h)
612 * @old_rate: old clk rate
613 * @new_rate: new clk rate
614 *
615 * Triggers a notifier call chain on the clk rate-change notification
616 * for 'clk'. Passes a pointer to the struct clk and the previous
617 * and current rates to the notifier callback. Intended to be called by
618 * internal clock code only. Returns NOTIFY_DONE from the last driver
619 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
620 * a driver returns that.
621 */
622static int __clk_notify(struct clk *clk, unsigned long msg,
623 unsigned long old_rate, unsigned long new_rate)
624{
625 struct clk_notifier *cn;
626 struct clk_notifier_data cnd;
627 int ret = NOTIFY_DONE;
628
629 cnd.clk = clk;
630 cnd.old_rate = old_rate;
631 cnd.new_rate = new_rate;
632
633 list_for_each_entry(cn, &clk_notifier_list, node) {
634 if (cn->clk == clk) {
635 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
636 &cnd);
637 break;
638 }
639 }
640
641 return ret;
642}
643
644/**
645 * __clk_recalc_rates
646 * @clk: first clk in the subtree
647 * @msg: notification type (see include/linux/clk.h)
648 *
649 * Walks the subtree of clks starting with clk and recalculates rates as it
650 * goes. Note that if a clk does not implement the .recalc_rate callback then
651 * it is assumed that the clock will take on the rate of it's parent.
652 *
653 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
654 * if necessary.
655 *
656 * Caller must hold prepare_lock.
657 */
658static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
659{
660 unsigned long old_rate;
661 unsigned long parent_rate = 0;
662 struct hlist_node *tmp;
663 struct clk *child;
664
665 old_rate = clk->rate;
666
667 if (clk->parent)
668 parent_rate = clk->parent->rate;
669
670 if (clk->ops->recalc_rate)
671 clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
672 else
673 clk->rate = parent_rate;
674
675 /*
676 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
677 * & ABORT_RATE_CHANGE notifiers
678 */
679 if (clk->notifier_count && msg)
680 __clk_notify(clk, msg, old_rate, clk->rate);
681
682 hlist_for_each_entry(child, tmp, &clk->children, child_node)
683 __clk_recalc_rates(child, msg);
684}
685
686/**
Ulf Hanssona093bde2012-08-31 14:21:28 +0200687 * clk_get_rate - return the rate of clk
688 * @clk: the clk whose rate is being returned
689 *
690 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
691 * is set, which means a recalc_rate will be issued.
692 * If clk is NULL then returns 0.
693 */
694unsigned long clk_get_rate(struct clk *clk)
695{
696 unsigned long rate;
697
698 mutex_lock(&prepare_lock);
699
700 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
701 __clk_recalc_rates(clk, 0);
702
703 rate = __clk_get_rate(clk);
704 mutex_unlock(&prepare_lock);
705
706 return rate;
707}
708EXPORT_SYMBOL_GPL(clk_get_rate);
709
710/**
Mike Turquetteb24764902012-03-15 23:11:19 -0700711 * __clk_speculate_rates
712 * @clk: first clk in the subtree
713 * @parent_rate: the "future" rate of clk's parent
714 *
715 * Walks the subtree of clks starting with clk, speculating rates as it
716 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
717 *
718 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
719 * pre-rate change notifications and returns early if no clks in the
720 * subtree have subscribed to the notifications. Note that if a clk does not
721 * implement the .recalc_rate callback then it is assumed that the clock will
722 * take on the rate of it's parent.
723 *
724 * Caller must hold prepare_lock.
725 */
726static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
727{
728 struct hlist_node *tmp;
729 struct clk *child;
730 unsigned long new_rate;
731 int ret = NOTIFY_DONE;
732
733 if (clk->ops->recalc_rate)
734 new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
735 else
736 new_rate = parent_rate;
737
738 /* abort the rate change if a driver returns NOTIFY_BAD */
739 if (clk->notifier_count)
740 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
741
742 if (ret == NOTIFY_BAD)
743 goto out;
744
745 hlist_for_each_entry(child, tmp, &clk->children, child_node) {
746 ret = __clk_speculate_rates(child, new_rate);
747 if (ret == NOTIFY_BAD)
748 break;
749 }
750
751out:
752 return ret;
753}
754
755static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
756{
757 struct clk *child;
758 struct hlist_node *tmp;
759
760 clk->new_rate = new_rate;
761
762 hlist_for_each_entry(child, tmp, &clk->children, child_node) {
763 if (child->ops->recalc_rate)
764 child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
765 else
766 child->new_rate = new_rate;
767 clk_calc_subtree(child, child->new_rate);
768 }
769}
770
771/*
772 * calculate the new rates returning the topmost clock that has to be
773 * changed.
774 */
775static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
776{
777 struct clk *top = clk;
Shawn Guo81536e02012-04-12 20:50:17 +0800778 unsigned long best_parent_rate = 0;
Mike Turquetteb24764902012-03-15 23:11:19 -0700779 unsigned long new_rate;
780
Mike Turquette7452b212012-03-26 14:45:36 -0700781 /* sanity */
782 if (IS_ERR_OR_NULL(clk))
783 return NULL;
784
Mike Turquette63f5c3b2012-05-02 16:23:43 -0700785 /* save parent rate, if it exists */
786 if (clk->parent)
787 best_parent_rate = clk->parent->rate;
788
Mike Turquette7452b212012-03-26 14:45:36 -0700789 /* never propagate up to the parent */
790 if (!(clk->flags & CLK_SET_RATE_PARENT)) {
791 if (!clk->ops->round_rate) {
792 clk->new_rate = clk->rate;
793 return NULL;
Mike Turquette7452b212012-03-26 14:45:36 -0700794 }
Mike Turquette63f5c3b2012-05-02 16:23:43 -0700795 new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
796 goto out;
Mike Turquette7452b212012-03-26 14:45:36 -0700797 }
798
799 /* need clk->parent from here on out */
800 if (!clk->parent) {
801 pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
Mike Turquetteb24764902012-03-15 23:11:19 -0700802 return NULL;
803 }
804
Mike Turquette7452b212012-03-26 14:45:36 -0700805 if (!clk->ops->round_rate) {
Mike Turquetteb24764902012-03-15 23:11:19 -0700806 top = clk_calc_new_rates(clk->parent, rate);
Viresh Kumar1b2f9902012-04-17 16:45:38 +0530807 new_rate = clk->parent->new_rate;
Mike Turquetteb24764902012-03-15 23:11:19 -0700808
809 goto out;
810 }
811
Mike Turquette7452b212012-03-26 14:45:36 -0700812 new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
Mike Turquetteb24764902012-03-15 23:11:19 -0700813
814 if (best_parent_rate != clk->parent->rate) {
815 top = clk_calc_new_rates(clk->parent, best_parent_rate);
816
817 goto out;
818 }
819
820out:
821 clk_calc_subtree(clk, new_rate);
822
823 return top;
824}
825
826/*
827 * Notify about rate changes in a subtree. Always walk down the whole tree
828 * so that in case of an error we can walk down the whole tree again and
829 * abort the change.
830 */
831static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
832{
833 struct hlist_node *tmp;
834 struct clk *child, *fail_clk = NULL;
835 int ret = NOTIFY_DONE;
836
837 if (clk->rate == clk->new_rate)
838 return 0;
839
840 if (clk->notifier_count) {
841 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
842 if (ret == NOTIFY_BAD)
843 fail_clk = clk;
844 }
845
846 hlist_for_each_entry(child, tmp, &clk->children, child_node) {
847 clk = clk_propagate_rate_change(child, event);
848 if (clk)
849 fail_clk = clk;
850 }
851
852 return fail_clk;
853}
854
855/*
856 * walk down a subtree and set the new rates notifying the rate
857 * change on the way
858 */
859static void clk_change_rate(struct clk *clk)
860{
861 struct clk *child;
862 unsigned long old_rate;
Pawel Mollbf47b4f2012-06-08 14:04:06 +0100863 unsigned long best_parent_rate = 0;
Mike Turquetteb24764902012-03-15 23:11:19 -0700864 struct hlist_node *tmp;
865
866 old_rate = clk->rate;
867
Pawel Mollbf47b4f2012-06-08 14:04:06 +0100868 if (clk->parent)
869 best_parent_rate = clk->parent->rate;
870
Mike Turquetteb24764902012-03-15 23:11:19 -0700871 if (clk->ops->set_rate)
Pawel Mollbf47b4f2012-06-08 14:04:06 +0100872 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
Mike Turquetteb24764902012-03-15 23:11:19 -0700873
874 if (clk->ops->recalc_rate)
Pawel Mollbf47b4f2012-06-08 14:04:06 +0100875 clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
Mike Turquetteb24764902012-03-15 23:11:19 -0700876 else
Pawel Mollbf47b4f2012-06-08 14:04:06 +0100877 clk->rate = best_parent_rate;
Mike Turquetteb24764902012-03-15 23:11:19 -0700878
879 if (clk->notifier_count && old_rate != clk->rate)
880 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
881
882 hlist_for_each_entry(child, tmp, &clk->children, child_node)
883 clk_change_rate(child);
884}
885
886/**
887 * clk_set_rate - specify a new rate for clk
888 * @clk: the clk whose rate is being changed
889 * @rate: the new rate for clk
890 *
Mike Turquette5654dc92012-03-26 11:51:34 -0700891 * In the simplest case clk_set_rate will only adjust the rate of clk.
Mike Turquetteb24764902012-03-15 23:11:19 -0700892 *
Mike Turquette5654dc92012-03-26 11:51:34 -0700893 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
894 * propagate up to clk's parent; whether or not this happens depends on the
895 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
896 * after calling .round_rate then upstream parent propagation is ignored. If
897 * *parent_rate comes back with a new rate for clk's parent then we propagate
898 * up to clk's parent and set it's rate. Upward propagation will continue
899 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
900 * .round_rate stops requesting changes to clk's parent_rate.
Mike Turquetteb24764902012-03-15 23:11:19 -0700901 *
Mike Turquette5654dc92012-03-26 11:51:34 -0700902 * Rate changes are accomplished via tree traversal that also recalculates the
903 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
Mike Turquetteb24764902012-03-15 23:11:19 -0700904 *
905 * Returns 0 on success, -EERROR otherwise.
906 */
907int clk_set_rate(struct clk *clk, unsigned long rate)
908{
909 struct clk *top, *fail_clk;
910 int ret = 0;
911
912 /* prevent racing with updates to the clock topology */
913 mutex_lock(&prepare_lock);
914
915 /* bail early if nothing to do */
916 if (rate == clk->rate)
917 goto out;
918
Saravana Kannan7e0fa1b2012-05-15 13:43:42 -0700919 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
Viresh Kumar0e1c0302012-04-11 16:03:42 +0530920 ret = -EBUSY;
921 goto out;
922 }
923
Mike Turquetteb24764902012-03-15 23:11:19 -0700924 /* calculate new rates and get the topmost changed clock */
925 top = clk_calc_new_rates(clk, rate);
926 if (!top) {
927 ret = -EINVAL;
928 goto out;
929 }
930
931 /* notify that we are about to change rates */
932 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
933 if (fail_clk) {
934 pr_warn("%s: failed to set %s rate\n", __func__,
935 fail_clk->name);
936 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
937 ret = -EBUSY;
938 goto out;
939 }
940
941 /* change the rates */
942 clk_change_rate(top);
943
944 mutex_unlock(&prepare_lock);
945
946 return 0;
947out:
948 mutex_unlock(&prepare_lock);
949
950 return ret;
951}
952EXPORT_SYMBOL_GPL(clk_set_rate);
953
954/**
955 * clk_get_parent - return the parent of a clk
956 * @clk: the clk whose parent gets returned
957 *
958 * Simply returns clk->parent. Returns NULL if clk is NULL.
959 */
960struct clk *clk_get_parent(struct clk *clk)
961{
962 struct clk *parent;
963
964 mutex_lock(&prepare_lock);
965 parent = __clk_get_parent(clk);
966 mutex_unlock(&prepare_lock);
967
968 return parent;
969}
970EXPORT_SYMBOL_GPL(clk_get_parent);
971
972/*
973 * .get_parent is mandatory for clocks with multiple possible parents. It is
974 * optional for single-parent clocks. Always call .get_parent if it is
975 * available and WARN if it is missing for multi-parent clocks.
976 *
977 * For single-parent clocks without .get_parent, first check to see if the
978 * .parents array exists, and if so use it to avoid an expensive tree
979 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
980 */
981static struct clk *__clk_init_parent(struct clk *clk)
982{
983 struct clk *ret = NULL;
984 u8 index;
985
986 /* handle the trivial cases */
987
988 if (!clk->num_parents)
989 goto out;
990
991 if (clk->num_parents == 1) {
992 if (IS_ERR_OR_NULL(clk->parent))
993 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
994 ret = clk->parent;
995 goto out;
996 }
997
998 if (!clk->ops->get_parent) {
999 WARN(!clk->ops->get_parent,
1000 "%s: multi-parent clocks must implement .get_parent\n",
1001 __func__);
1002 goto out;
1003 };
1004
1005 /*
1006 * Do our best to cache parent clocks in clk->parents. This prevents
1007 * unnecessary and expensive calls to __clk_lookup. We don't set
1008 * clk->parent here; that is done by the calling function
1009 */
1010
1011 index = clk->ops->get_parent(clk->hw);
1012
1013 if (!clk->parents)
1014 clk->parents =
Rajendra Nayak79750592012-06-06 14:41:31 +05301015 kzalloc((sizeof(struct clk*) * clk->num_parents),
Mike Turquetteb24764902012-03-15 23:11:19 -07001016 GFP_KERNEL);
1017
1018 if (!clk->parents)
1019 ret = __clk_lookup(clk->parent_names[index]);
1020 else if (!clk->parents[index])
1021 ret = clk->parents[index] =
1022 __clk_lookup(clk->parent_names[index]);
1023 else
1024 ret = clk->parents[index];
1025
1026out:
1027 return ret;
1028}
1029
1030void __clk_reparent(struct clk *clk, struct clk *new_parent)
1031{
1032#ifdef CONFIG_COMMON_CLK_DEBUG
1033 struct dentry *d;
1034 struct dentry *new_parent_d;
1035#endif
1036
1037 if (!clk || !new_parent)
1038 return;
1039
1040 hlist_del(&clk->child_node);
1041
1042 if (new_parent)
1043 hlist_add_head(&clk->child_node, &new_parent->children);
1044 else
1045 hlist_add_head(&clk->child_node, &clk_orphan_list);
1046
1047#ifdef CONFIG_COMMON_CLK_DEBUG
1048 if (!inited)
1049 goto out;
1050
1051 if (new_parent)
1052 new_parent_d = new_parent->dentry;
1053 else
1054 new_parent_d = orphandir;
1055
1056 d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
1057 new_parent_d, clk->name);
1058 if (d)
1059 clk->dentry = d;
1060 else
1061 pr_debug("%s: failed to rename debugfs entry for %s\n",
1062 __func__, clk->name);
1063out:
1064#endif
1065
1066 clk->parent = new_parent;
1067
1068 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1069}
1070
1071static int __clk_set_parent(struct clk *clk, struct clk *parent)
1072{
1073 struct clk *old_parent;
1074 unsigned long flags;
1075 int ret = -EINVAL;
1076 u8 i;
1077
1078 old_parent = clk->parent;
1079
Rajendra Nayak863b1322012-07-03 12:11:41 +05301080 if (!clk->parents)
Rajendra Nayak79750592012-06-06 14:41:31 +05301081 clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1082 GFP_KERNEL);
Mike Turquetteb24764902012-03-15 23:11:19 -07001083
1084 /*
Rajendra Nayak863b1322012-07-03 12:11:41 +05301085 * find index of new parent clock using cached parent ptrs,
1086 * or if not yet cached, use string name comparison and cache
1087 * them now to avoid future calls to __clk_lookup.
Mike Turquetteb24764902012-03-15 23:11:19 -07001088 */
Rajendra Nayak863b1322012-07-03 12:11:41 +05301089 for (i = 0; i < clk->num_parents; i++) {
1090 if (clk->parents && clk->parents[i] == parent)
1091 break;
1092 else if (!strcmp(clk->parent_names[i], parent->name)) {
1093 if (clk->parents)
1094 clk->parents[i] = __clk_lookup(parent->name);
1095 break;
1096 }
1097 }
Mike Turquetteb24764902012-03-15 23:11:19 -07001098
1099 if (i == clk->num_parents) {
1100 pr_debug("%s: clock %s is not a possible parent of clock %s\n",
1101 __func__, parent->name, clk->name);
1102 goto out;
1103 }
1104
1105 /* migrate prepare and enable */
1106 if (clk->prepare_count)
1107 __clk_prepare(parent);
1108
1109 /* FIXME replace with clk_is_enabled(clk) someday */
1110 spin_lock_irqsave(&enable_lock, flags);
1111 if (clk->enable_count)
1112 __clk_enable(parent);
1113 spin_unlock_irqrestore(&enable_lock, flags);
1114
1115 /* change clock input source */
1116 ret = clk->ops->set_parent(clk->hw, i);
1117
1118 /* clean up old prepare and enable */
1119 spin_lock_irqsave(&enable_lock, flags);
1120 if (clk->enable_count)
1121 __clk_disable(old_parent);
1122 spin_unlock_irqrestore(&enable_lock, flags);
1123
1124 if (clk->prepare_count)
1125 __clk_unprepare(old_parent);
1126
1127out:
1128 return ret;
1129}
1130
1131/**
1132 * clk_set_parent - switch the parent of a mux clk
1133 * @clk: the mux clk whose input we are switching
1134 * @parent: the new input to clk
1135 *
1136 * Re-parent clk to use parent as it's new input source. If clk has the
1137 * CLK_SET_PARENT_GATE flag set then clk must be gated for this
1138 * operation to succeed. After successfully changing clk's parent
1139 * clk_set_parent will update the clk topology, sysfs topology and
1140 * propagate rate recalculation via __clk_recalc_rates. Returns 0 on
1141 * success, -EERROR otherwise.
1142 */
1143int clk_set_parent(struct clk *clk, struct clk *parent)
1144{
1145 int ret = 0;
1146
1147 if (!clk || !clk->ops)
1148 return -EINVAL;
1149
1150 if (!clk->ops->set_parent)
1151 return -ENOSYS;
1152
1153 /* prevent racing with updates to the clock topology */
1154 mutex_lock(&prepare_lock);
1155
1156 if (clk->parent == parent)
1157 goto out;
1158
1159 /* propagate PRE_RATE_CHANGE notifications */
1160 if (clk->notifier_count)
1161 ret = __clk_speculate_rates(clk, parent->rate);
1162
1163 /* abort if a driver objects */
1164 if (ret == NOTIFY_STOP)
1165 goto out;
1166
1167 /* only re-parent if the clock is not in use */
1168 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count)
1169 ret = -EBUSY;
1170 else
1171 ret = __clk_set_parent(clk, parent);
1172
1173 /* propagate ABORT_RATE_CHANGE if .set_parent failed */
1174 if (ret) {
1175 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1176 goto out;
1177 }
1178
1179 /* propagate rate recalculation downstream */
1180 __clk_reparent(clk, parent);
1181
1182out:
1183 mutex_unlock(&prepare_lock);
1184
1185 return ret;
1186}
1187EXPORT_SYMBOL_GPL(clk_set_parent);
1188
1189/**
1190 * __clk_init - initialize the data structures in a struct clk
1191 * @dev: device initializing this clk, placeholder for now
1192 * @clk: clk being initialized
1193 *
1194 * Initializes the lists in struct clk, queries the hardware for the
1195 * parent and rate and sets them both.
Mike Turquetteb24764902012-03-15 23:11:19 -07001196 */
Mike Turquetted1302a32012-03-29 14:30:40 -07001197int __clk_init(struct device *dev, struct clk *clk)
Mike Turquetteb24764902012-03-15 23:11:19 -07001198{
Mike Turquetted1302a32012-03-29 14:30:40 -07001199 int i, ret = 0;
Mike Turquetteb24764902012-03-15 23:11:19 -07001200 struct clk *orphan;
1201 struct hlist_node *tmp, *tmp2;
1202
1203 if (!clk)
Mike Turquetted1302a32012-03-29 14:30:40 -07001204 return -EINVAL;
Mike Turquetteb24764902012-03-15 23:11:19 -07001205
1206 mutex_lock(&prepare_lock);
1207
1208 /* check to see if a clock with this name is already registered */
Mike Turquetted1302a32012-03-29 14:30:40 -07001209 if (__clk_lookup(clk->name)) {
1210 pr_debug("%s: clk %s already initialized\n",
1211 __func__, clk->name);
1212 ret = -EEXIST;
Mike Turquetteb24764902012-03-15 23:11:19 -07001213 goto out;
Mike Turquetted1302a32012-03-29 14:30:40 -07001214 }
Mike Turquetteb24764902012-03-15 23:11:19 -07001215
Mike Turquetted4d7e3d2012-03-26 16:15:52 -07001216 /* check that clk_ops are sane. See Documentation/clk.txt */
1217 if (clk->ops->set_rate &&
1218 !(clk->ops->round_rate && clk->ops->recalc_rate)) {
1219 pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
1220 __func__, clk->name);
Mike Turquetted1302a32012-03-29 14:30:40 -07001221 ret = -EINVAL;
Mike Turquetted4d7e3d2012-03-26 16:15:52 -07001222 goto out;
1223 }
1224
1225 if (clk->ops->set_parent && !clk->ops->get_parent) {
1226 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1227 __func__, clk->name);
Mike Turquetted1302a32012-03-29 14:30:40 -07001228 ret = -EINVAL;
Mike Turquetted4d7e3d2012-03-26 16:15:52 -07001229 goto out;
1230 }
1231
Mike Turquetteb24764902012-03-15 23:11:19 -07001232 /* throw a WARN if any entries in parent_names are NULL */
1233 for (i = 0; i < clk->num_parents; i++)
1234 WARN(!clk->parent_names[i],
1235 "%s: invalid NULL in %s's .parent_names\n",
1236 __func__, clk->name);
1237
1238 /*
1239 * Allocate an array of struct clk *'s to avoid unnecessary string
1240 * look-ups of clk's possible parents. This can fail for clocks passed
1241 * in to clk_init during early boot; thus any access to clk->parents[]
1242 * must always check for a NULL pointer and try to populate it if
1243 * necessary.
1244 *
1245 * If clk->parents is not NULL we skip this entire block. This allows
1246 * for clock drivers to statically initialize clk->parents.
1247 */
Rajendra Nayak9ca1c5a2012-06-06 14:41:30 +05301248 if (clk->num_parents > 1 && !clk->parents) {
1249 clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
Mike Turquetteb24764902012-03-15 23:11:19 -07001250 GFP_KERNEL);
1251 /*
1252 * __clk_lookup returns NULL for parents that have not been
1253 * clk_init'd; thus any access to clk->parents[] must check
1254 * for a NULL pointer. We can always perform lazy lookups for
1255 * missing parents later on.
1256 */
1257 if (clk->parents)
1258 for (i = 0; i < clk->num_parents; i++)
1259 clk->parents[i] =
1260 __clk_lookup(clk->parent_names[i]);
1261 }
1262
1263 clk->parent = __clk_init_parent(clk);
1264
1265 /*
1266 * Populate clk->parent if parent has already been __clk_init'd. If
1267 * parent has not yet been __clk_init'd then place clk in the orphan
1268 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1269 * clk list.
1270 *
1271 * Every time a new clk is clk_init'd then we walk the list of orphan
1272 * clocks and re-parent any that are children of the clock currently
1273 * being clk_init'd.
1274 */
1275 if (clk->parent)
1276 hlist_add_head(&clk->child_node,
1277 &clk->parent->children);
1278 else if (clk->flags & CLK_IS_ROOT)
1279 hlist_add_head(&clk->child_node, &clk_root_list);
1280 else
1281 hlist_add_head(&clk->child_node, &clk_orphan_list);
1282
1283 /*
1284 * Set clk's rate. The preferred method is to use .recalc_rate. For
1285 * simple clocks and lazy developers the default fallback is to use the
1286 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1287 * then rate is set to zero.
1288 */
1289 if (clk->ops->recalc_rate)
1290 clk->rate = clk->ops->recalc_rate(clk->hw,
1291 __clk_get_rate(clk->parent));
1292 else if (clk->parent)
1293 clk->rate = clk->parent->rate;
1294 else
1295 clk->rate = 0;
1296
1297 /*
1298 * walk the list of orphan clocks and reparent any that are children of
1299 * this clock
1300 */
Martin Fuzzey1f61e5f2012-11-22 20:15:05 +01001301 hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node) {
1302 if (orphan->ops->get_parent) {
1303 i = orphan->ops->get_parent(orphan->hw);
1304 if (!strcmp(clk->name, orphan->parent_names[i]))
1305 __clk_reparent(orphan, clk);
1306 continue;
1307 }
1308
Mike Turquetteb24764902012-03-15 23:11:19 -07001309 for (i = 0; i < orphan->num_parents; i++)
1310 if (!strcmp(clk->name, orphan->parent_names[i])) {
1311 __clk_reparent(orphan, clk);
1312 break;
1313 }
Martin Fuzzey1f61e5f2012-11-22 20:15:05 +01001314 }
Mike Turquetteb24764902012-03-15 23:11:19 -07001315
1316 /*
1317 * optional platform-specific magic
1318 *
1319 * The .init callback is not used by any of the basic clock types, but
1320 * exists for weird hardware that must perform initialization magic.
1321 * Please consider other ways of solving initialization problems before
1322 * using this callback, as it's use is discouraged.
1323 */
1324 if (clk->ops->init)
1325 clk->ops->init(clk->hw);
1326
1327 clk_debug_register(clk);
1328
1329out:
1330 mutex_unlock(&prepare_lock);
1331
Mike Turquetted1302a32012-03-29 14:30:40 -07001332 return ret;
Mike Turquetteb24764902012-03-15 23:11:19 -07001333}
1334
1335/**
Saravana Kannan0197b3e2012-04-25 22:58:56 -07001336 * __clk_register - register a clock and return a cookie.
1337 *
1338 * Same as clk_register, except that the .clk field inside hw shall point to a
1339 * preallocated (generally statically allocated) struct clk. None of the fields
1340 * of the struct clk need to be initialized.
1341 *
1342 * The data pointed to by .init and .clk field shall NOT be marked as init
1343 * data.
1344 *
1345 * __clk_register is only exposed via clk-private.h and is intended for use with
1346 * very large numbers of clocks that need to be statically initialized. It is
1347 * a layering violation to include clk-private.h from any code which implements
1348 * a clock's .ops; as such any statically initialized clock data MUST be in a
1349 * separate C file from the logic that implements it's operations. Returns 0
1350 * on success, otherwise an error code.
1351 */
1352struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1353{
1354 int ret;
1355 struct clk *clk;
1356
1357 clk = hw->clk;
1358 clk->name = hw->init->name;
1359 clk->ops = hw->init->ops;
1360 clk->hw = hw;
1361 clk->flags = hw->init->flags;
1362 clk->parent_names = hw->init->parent_names;
1363 clk->num_parents = hw->init->num_parents;
1364
1365 ret = __clk_init(dev, clk);
1366 if (ret)
1367 return ERR_PTR(ret);
1368
1369 return clk;
1370}
1371EXPORT_SYMBOL_GPL(__clk_register);
1372
Stephen Boyd46c87732012-09-24 13:38:04 -07001373static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
Mike Turquetteb24764902012-03-15 23:11:19 -07001374{
Mike Turquetted1302a32012-03-29 14:30:40 -07001375 int i, ret;
Mike Turquetteb24764902012-03-15 23:11:19 -07001376
Saravana Kannan0197b3e2012-04-25 22:58:56 -07001377 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1378 if (!clk->name) {
1379 pr_err("%s: could not allocate clk->name\n", __func__);
1380 ret = -ENOMEM;
1381 goto fail_name;
1382 }
1383 clk->ops = hw->init->ops;
Mike Turquetteb24764902012-03-15 23:11:19 -07001384 clk->hw = hw;
Saravana Kannan0197b3e2012-04-25 22:58:56 -07001385 clk->flags = hw->init->flags;
1386 clk->num_parents = hw->init->num_parents;
Mike Turquetteb24764902012-03-15 23:11:19 -07001387 hw->clk = clk;
1388
Mike Turquetted1302a32012-03-29 14:30:40 -07001389 /* allocate local copy in case parent_names is __initdata */
Saravana Kannan0197b3e2012-04-25 22:58:56 -07001390 clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents),
Mike Turquetted1302a32012-03-29 14:30:40 -07001391 GFP_KERNEL);
Mike Turquetteb24764902012-03-15 23:11:19 -07001392
Mike Turquetted1302a32012-03-29 14:30:40 -07001393 if (!clk->parent_names) {
1394 pr_err("%s: could not allocate clk->parent_names\n", __func__);
1395 ret = -ENOMEM;
1396 goto fail_parent_names;
1397 }
1398
1399
1400 /* copy each string name in case parent_names is __initdata */
Saravana Kannan0197b3e2012-04-25 22:58:56 -07001401 for (i = 0; i < clk->num_parents; i++) {
1402 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1403 GFP_KERNEL);
Mike Turquetted1302a32012-03-29 14:30:40 -07001404 if (!clk->parent_names[i]) {
1405 pr_err("%s: could not copy parent_names\n", __func__);
1406 ret = -ENOMEM;
1407 goto fail_parent_names_copy;
1408 }
1409 }
1410
1411 ret = __clk_init(dev, clk);
1412 if (!ret)
Stephen Boyd46c87732012-09-24 13:38:04 -07001413 return 0;
Mike Turquetted1302a32012-03-29 14:30:40 -07001414
1415fail_parent_names_copy:
1416 while (--i >= 0)
1417 kfree(clk->parent_names[i]);
1418 kfree(clk->parent_names);
1419fail_parent_names:
Saravana Kannan0197b3e2012-04-25 22:58:56 -07001420 kfree(clk->name);
1421fail_name:
Stephen Boyd46c87732012-09-24 13:38:04 -07001422 return ret;
1423}
1424
1425/**
1426 * clk_register - allocate a new clock, register it and return an opaque cookie
1427 * @dev: device that is registering this clock
1428 * @hw: link to hardware-specific clock data
1429 *
1430 * clk_register is the primary interface for populating the clock tree with new
1431 * clock nodes. It returns a pointer to the newly allocated struct clk which
1432 * cannot be dereferenced by driver code but may be used in conjuction with the
1433 * rest of the clock API. In the event of an error clk_register will return an
1434 * error code; drivers must test for an error code after calling clk_register.
1435 */
1436struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1437{
1438 int ret;
1439 struct clk *clk;
1440
1441 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1442 if (!clk) {
1443 pr_err("%s: could not allocate clk\n", __func__);
1444 ret = -ENOMEM;
1445 goto fail_out;
1446 }
1447
1448 ret = _clk_register(dev, hw, clk);
1449 if (!ret)
1450 return clk;
1451
Mike Turquetted1302a32012-03-29 14:30:40 -07001452 kfree(clk);
1453fail_out:
1454 return ERR_PTR(ret);
Mike Turquetteb24764902012-03-15 23:11:19 -07001455}
1456EXPORT_SYMBOL_GPL(clk_register);
1457
Mark Brown1df5c932012-04-18 09:07:12 +01001458/**
1459 * clk_unregister - unregister a currently registered clock
1460 * @clk: clock to unregister
1461 *
1462 * Currently unimplemented.
1463 */
1464void clk_unregister(struct clk *clk) {}
1465EXPORT_SYMBOL_GPL(clk_unregister);
1466
Stephen Boyd46c87732012-09-24 13:38:04 -07001467static void devm_clk_release(struct device *dev, void *res)
1468{
1469 clk_unregister(res);
1470}
1471
1472/**
1473 * devm_clk_register - resource managed clk_register()
1474 * @dev: device that is registering this clock
1475 * @hw: link to hardware-specific clock data
1476 *
1477 * Managed clk_register(). Clocks returned from this function are
1478 * automatically clk_unregister()ed on driver detach. See clk_register() for
1479 * more information.
1480 */
1481struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
1482{
1483 struct clk *clk;
1484 int ret;
1485
1486 clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
1487 if (!clk)
1488 return ERR_PTR(-ENOMEM);
1489
1490 ret = _clk_register(dev, hw, clk);
1491 if (!ret) {
1492 devres_add(dev, clk);
1493 } else {
1494 devres_free(clk);
1495 clk = ERR_PTR(ret);
1496 }
1497
1498 return clk;
1499}
1500EXPORT_SYMBOL_GPL(devm_clk_register);
1501
1502static int devm_clk_match(struct device *dev, void *res, void *data)
1503{
1504 struct clk *c = res;
1505 if (WARN_ON(!c))
1506 return 0;
1507 return c == data;
1508}
1509
1510/**
1511 * devm_clk_unregister - resource managed clk_unregister()
1512 * @clk: clock to unregister
1513 *
1514 * Deallocate a clock allocated with devm_clk_register(). Normally
1515 * this function will not need to be called and the resource management
1516 * code will ensure that the resource is freed.
1517 */
1518void devm_clk_unregister(struct device *dev, struct clk *clk)
1519{
1520 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
1521}
1522EXPORT_SYMBOL_GPL(devm_clk_unregister);
1523
Mike Turquetteb24764902012-03-15 23:11:19 -07001524/*** clk rate change notifiers ***/
1525
1526/**
1527 * clk_notifier_register - add a clk rate change notifier
1528 * @clk: struct clk * to watch
1529 * @nb: struct notifier_block * with callback info
1530 *
1531 * Request notification when clk's rate changes. This uses an SRCU
1532 * notifier because we want it to block and notifier unregistrations are
1533 * uncommon. The callbacks associated with the notifier must not
1534 * re-enter into the clk framework by calling any top-level clk APIs;
1535 * this will cause a nested prepare_lock mutex.
1536 *
1537 * Pre-change notifier callbacks will be passed the current, pre-change
1538 * rate of the clk via struct clk_notifier_data.old_rate. The new,
1539 * post-change rate of the clk is passed via struct
1540 * clk_notifier_data.new_rate.
1541 *
1542 * Post-change notifiers will pass the now-current, post-change rate of
1543 * the clk in both struct clk_notifier_data.old_rate and struct
1544 * clk_notifier_data.new_rate.
1545 *
1546 * Abort-change notifiers are effectively the opposite of pre-change
1547 * notifiers: the original pre-change clk rate is passed in via struct
1548 * clk_notifier_data.new_rate and the failed post-change rate is passed
1549 * in via struct clk_notifier_data.old_rate.
1550 *
1551 * clk_notifier_register() must be called from non-atomic context.
1552 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1553 * allocation failure; otherwise, passes along the return value of
1554 * srcu_notifier_chain_register().
1555 */
1556int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
1557{
1558 struct clk_notifier *cn;
1559 int ret = -ENOMEM;
1560
1561 if (!clk || !nb)
1562 return -EINVAL;
1563
1564 mutex_lock(&prepare_lock);
1565
1566 /* search the list of notifiers for this clk */
1567 list_for_each_entry(cn, &clk_notifier_list, node)
1568 if (cn->clk == clk)
1569 break;
1570
1571 /* if clk wasn't in the notifier list, allocate new clk_notifier */
1572 if (cn->clk != clk) {
1573 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
1574 if (!cn)
1575 goto out;
1576
1577 cn->clk = clk;
1578 srcu_init_notifier_head(&cn->notifier_head);
1579
1580 list_add(&cn->node, &clk_notifier_list);
1581 }
1582
1583 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
1584
1585 clk->notifier_count++;
1586
1587out:
1588 mutex_unlock(&prepare_lock);
1589
1590 return ret;
1591}
1592EXPORT_SYMBOL_GPL(clk_notifier_register);
1593
1594/**
1595 * clk_notifier_unregister - remove a clk rate change notifier
1596 * @clk: struct clk *
1597 * @nb: struct notifier_block * with callback info
1598 *
1599 * Request no further notification for changes to 'clk' and frees memory
1600 * allocated in clk_notifier_register.
1601 *
1602 * Returns -EINVAL if called with null arguments; otherwise, passes
1603 * along the return value of srcu_notifier_chain_unregister().
1604 */
1605int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
1606{
1607 struct clk_notifier *cn = NULL;
1608 int ret = -EINVAL;
1609
1610 if (!clk || !nb)
1611 return -EINVAL;
1612
1613 mutex_lock(&prepare_lock);
1614
1615 list_for_each_entry(cn, &clk_notifier_list, node)
1616 if (cn->clk == clk)
1617 break;
1618
1619 if (cn->clk == clk) {
1620 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
1621
1622 clk->notifier_count--;
1623
1624 /* XXX the notifier code should handle this better */
1625 if (!cn->notifier_head.head) {
1626 srcu_cleanup_notifier_head(&cn->notifier_head);
1627 kfree(cn);
1628 }
1629
1630 } else {
1631 ret = -ENOENT;
1632 }
1633
1634 mutex_unlock(&prepare_lock);
1635
1636 return ret;
1637}
1638EXPORT_SYMBOL_GPL(clk_notifier_unregister);
Grant Likely766e6a42012-04-09 14:50:06 -05001639
1640#ifdef CONFIG_OF
1641/**
1642 * struct of_clk_provider - Clock provider registration structure
1643 * @link: Entry in global list of clock providers
1644 * @node: Pointer to device tree node of clock provider
1645 * @get: Get clock callback. Returns NULL or a struct clk for the
1646 * given clock specifier
1647 * @data: context pointer to be passed into @get callback
1648 */
1649struct of_clk_provider {
1650 struct list_head link;
1651
1652 struct device_node *node;
1653 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
1654 void *data;
1655};
1656
1657static LIST_HEAD(of_clk_providers);
1658static DEFINE_MUTEX(of_clk_lock);
1659
1660struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
1661 void *data)
1662{
1663 return data;
1664}
1665EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
1666
Shawn Guo494bfec2012-08-22 21:36:27 +08001667struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
1668{
1669 struct clk_onecell_data *clk_data = data;
1670 unsigned int idx = clkspec->args[0];
1671
1672 if (idx >= clk_data->clk_num) {
1673 pr_err("%s: invalid clock index %d\n", __func__, idx);
1674 return ERR_PTR(-EINVAL);
1675 }
1676
1677 return clk_data->clks[idx];
1678}
1679EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
1680
Grant Likely766e6a42012-04-09 14:50:06 -05001681/**
1682 * of_clk_add_provider() - Register a clock provider for a node
1683 * @np: Device node pointer associated with clock provider
1684 * @clk_src_get: callback for decoding clock
1685 * @data: context pointer for @clk_src_get callback.
1686 */
1687int of_clk_add_provider(struct device_node *np,
1688 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
1689 void *data),
1690 void *data)
1691{
1692 struct of_clk_provider *cp;
1693
1694 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
1695 if (!cp)
1696 return -ENOMEM;
1697
1698 cp->node = of_node_get(np);
1699 cp->data = data;
1700 cp->get = clk_src_get;
1701
1702 mutex_lock(&of_clk_lock);
1703 list_add(&cp->link, &of_clk_providers);
1704 mutex_unlock(&of_clk_lock);
1705 pr_debug("Added clock from %s\n", np->full_name);
1706
1707 return 0;
1708}
1709EXPORT_SYMBOL_GPL(of_clk_add_provider);
1710
1711/**
1712 * of_clk_del_provider() - Remove a previously registered clock provider
1713 * @np: Device node pointer associated with clock provider
1714 */
1715void of_clk_del_provider(struct device_node *np)
1716{
1717 struct of_clk_provider *cp;
1718
1719 mutex_lock(&of_clk_lock);
1720 list_for_each_entry(cp, &of_clk_providers, link) {
1721 if (cp->node == np) {
1722 list_del(&cp->link);
1723 of_node_put(cp->node);
1724 kfree(cp);
1725 break;
1726 }
1727 }
1728 mutex_unlock(&of_clk_lock);
1729}
1730EXPORT_SYMBOL_GPL(of_clk_del_provider);
1731
1732struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
1733{
1734 struct of_clk_provider *provider;
1735 struct clk *clk = ERR_PTR(-ENOENT);
1736
1737 /* Check if we have such a provider in our array */
1738 mutex_lock(&of_clk_lock);
1739 list_for_each_entry(provider, &of_clk_providers, link) {
1740 if (provider->node == clkspec->np)
1741 clk = provider->get(clkspec, provider->data);
1742 if (!IS_ERR(clk))
1743 break;
1744 }
1745 mutex_unlock(&of_clk_lock);
1746
1747 return clk;
1748}
1749
1750const char *of_clk_get_parent_name(struct device_node *np, int index)
1751{
1752 struct of_phandle_args clkspec;
1753 const char *clk_name;
1754 int rc;
1755
1756 if (index < 0)
1757 return NULL;
1758
1759 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
1760 &clkspec);
1761 if (rc)
1762 return NULL;
1763
1764 if (of_property_read_string_index(clkspec.np, "clock-output-names",
1765 clkspec.args_count ? clkspec.args[0] : 0,
1766 &clk_name) < 0)
1767 clk_name = clkspec.np->name;
1768
1769 of_node_put(clkspec.np);
1770 return clk_name;
1771}
1772EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
1773
1774/**
1775 * of_clk_init() - Scan and init clock providers from the DT
1776 * @matches: array of compatible values and init functions for providers.
1777 *
1778 * This function scans the device tree for matching clock providers and
1779 * calls their initialization functions
1780 */
1781void __init of_clk_init(const struct of_device_id *matches)
1782{
1783 struct device_node *np;
1784
1785 for_each_matching_node(np, matches) {
1786 const struct of_device_id *match = of_match_node(matches, np);
1787 of_clk_init_cb_t clk_init_cb = match->data;
1788 clk_init_cb(np);
1789 }
1790}
1791#endif