2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
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.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
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>
21 static DEFINE_SPINLOCK(enable_lock
);
22 static DEFINE_MUTEX(prepare_lock
);
24 static HLIST_HEAD(clk_root_list
);
25 static HLIST_HEAD(clk_orphan_list
);
26 static LIST_HEAD(clk_notifier_list
);
28 /*** debugfs support ***/
30 #ifdef CONFIG_COMMON_CLK_DEBUG
31 #include <linux/debugfs.h>
33 static struct dentry
*rootdir
;
34 static struct dentry
*orphandir
;
35 static int inited
= 0;
37 /* caller must hold prepare_lock */
38 static int clk_debug_create_one(struct clk
*clk
, struct dentry
*pdentry
)
43 if (!clk
|| !pdentry
) {
48 d
= debugfs_create_dir(clk
->name
, pdentry
);
54 d
= debugfs_create_u32("clk_rate", S_IRUGO
, clk
->dentry
,
59 d
= debugfs_create_x32("clk_flags", S_IRUGO
, clk
->dentry
,
64 d
= debugfs_create_u32("clk_prepare_count", S_IRUGO
, clk
->dentry
,
65 (u32
*)&clk
->prepare_count
);
69 d
= debugfs_create_u32("clk_enable_count", S_IRUGO
, clk
->dentry
,
70 (u32
*)&clk
->enable_count
);
74 d
= debugfs_create_u32("clk_notifier_count", S_IRUGO
, clk
->dentry
,
75 (u32
*)&clk
->notifier_count
);
83 debugfs_remove(clk
->dentry
);
88 /* caller must hold prepare_lock */
89 static int clk_debug_create_subtree(struct clk
*clk
, struct dentry
*pdentry
)
92 struct hlist_node
*tmp
;
98 ret
= clk_debug_create_one(clk
, pdentry
);
103 hlist_for_each_entry(child
, tmp
, &clk
->children
, child_node
)
104 clk_debug_create_subtree(child
, clk
->dentry
);
112 * clk_debug_register - add a clk node to the debugfs clk tree
113 * @clk: the clk being added to the debugfs clk tree
115 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
116 * initialized. Otherwise it bails out early since the debugfs clk tree
117 * will be created lazily by clk_debug_init as part of a late_initcall.
119 * Caller must hold prepare_lock. Only clk_init calls this function (so
120 * far) so this is taken care.
122 static int clk_debug_register(struct clk
*clk
)
125 struct dentry
*pdentry
;
131 parent
= clk
->parent
;
134 * Check to see if a clk is a root clk. Also check that it is
135 * safe to add this clk to debugfs
138 if (clk
->flags
& CLK_IS_ROOT
)
144 pdentry
= parent
->dentry
;
148 ret
= clk_debug_create_subtree(clk
, pdentry
);
155 * clk_debug_init - lazily create the debugfs clk tree visualization
157 * clks are often initialized very early during boot before memory can
158 * be dynamically allocated and well before debugfs is setup.
159 * clk_debug_init walks the clk tree hierarchy while holding
160 * prepare_lock and creates the topology as part of a late_initcall,
161 * thus insuring that clks initialized very early will still be
162 * represented in the debugfs clk tree. This function should only be
163 * called once at boot-time, and all other clks added dynamically will
164 * be done so with clk_debug_register.
166 static int __init
clk_debug_init(void)
169 struct hlist_node
*tmp
;
171 rootdir
= debugfs_create_dir("clk", NULL
);
176 orphandir
= debugfs_create_dir("orphans", rootdir
);
181 mutex_lock(&prepare_lock
);
183 hlist_for_each_entry(clk
, tmp
, &clk_root_list
, child_node
)
184 clk_debug_create_subtree(clk
, rootdir
);
186 hlist_for_each_entry(clk
, tmp
, &clk_orphan_list
, child_node
)
187 clk_debug_create_subtree(clk
, orphandir
);
191 mutex_unlock(&prepare_lock
);
195 late_initcall(clk_debug_init
);
197 static inline int clk_debug_register(struct clk
*clk
) { return 0; }
200 /* caller must hold prepare_lock */
201 static void clk_disable_unused_subtree(struct clk
*clk
)
204 struct hlist_node
*tmp
;
210 hlist_for_each_entry(child
, tmp
, &clk
->children
, child_node
)
211 clk_disable_unused_subtree(child
);
213 spin_lock_irqsave(&enable_lock
, flags
);
215 if (clk
->enable_count
)
218 if (clk
->flags
& CLK_IGNORE_UNUSED
)
221 if (__clk_is_enabled(clk
) && clk
->ops
->disable
)
222 clk
->ops
->disable(clk
->hw
);
225 spin_unlock_irqrestore(&enable_lock
, flags
);
231 static int clk_disable_unused(void)
234 struct hlist_node
*tmp
;
236 mutex_lock(&prepare_lock
);
238 hlist_for_each_entry(clk
, tmp
, &clk_root_list
, child_node
)
239 clk_disable_unused_subtree(clk
);
241 hlist_for_each_entry(clk
, tmp
, &clk_orphan_list
, child_node
)
242 clk_disable_unused_subtree(clk
);
244 mutex_unlock(&prepare_lock
);
248 late_initcall(clk_disable_unused
);
250 /*** helper functions ***/
252 inline const char *__clk_get_name(struct clk
*clk
)
254 return !clk
? NULL
: clk
->name
;
257 inline struct clk_hw
*__clk_get_hw(struct clk
*clk
)
259 return !clk
? NULL
: clk
->hw
;
262 inline u8
__clk_get_num_parents(struct clk
*clk
)
264 return !clk
? -EINVAL
: clk
->num_parents
;
267 inline struct clk
*__clk_get_parent(struct clk
*clk
)
269 return !clk
? NULL
: clk
->parent
;
272 inline int __clk_get_enable_count(struct clk
*clk
)
274 return !clk
? -EINVAL
: clk
->enable_count
;
277 inline int __clk_get_prepare_count(struct clk
*clk
)
279 return !clk
? -EINVAL
: clk
->prepare_count
;
282 unsigned long __clk_get_rate(struct clk
*clk
)
293 if (clk
->flags
& CLK_IS_ROOT
)
303 inline unsigned long __clk_get_flags(struct clk
*clk
)
305 return !clk
? -EINVAL
: clk
->flags
;
308 int __clk_is_enabled(struct clk
*clk
)
316 * .is_enabled is only mandatory for clocks that gate
317 * fall back to software usage counter if .is_enabled is missing
319 if (!clk
->ops
->is_enabled
) {
320 ret
= clk
->enable_count
? 1 : 0;
324 ret
= clk
->ops
->is_enabled(clk
->hw
);
329 static struct clk
*__clk_lookup_subtree(const char *name
, struct clk
*clk
)
333 struct hlist_node
*tmp
;
335 if (!strcmp(clk
->name
, name
))
338 hlist_for_each_entry(child
, tmp
, &clk
->children
, child_node
) {
339 ret
= __clk_lookup_subtree(name
, child
);
347 struct clk
*__clk_lookup(const char *name
)
349 struct clk
*root_clk
;
351 struct hlist_node
*tmp
;
356 /* search the 'proper' clk tree first */
357 hlist_for_each_entry(root_clk
, tmp
, &clk_root_list
, child_node
) {
358 ret
= __clk_lookup_subtree(name
, root_clk
);
363 /* if not found, then search the orphan tree */
364 hlist_for_each_entry(root_clk
, tmp
, &clk_orphan_list
, child_node
) {
365 ret
= __clk_lookup_subtree(name
, root_clk
);
375 void __clk_unprepare(struct clk
*clk
)
380 if (WARN_ON(clk
->prepare_count
== 0))
383 if (--clk
->prepare_count
> 0)
386 WARN_ON(clk
->enable_count
> 0);
388 if (clk
->ops
->unprepare
)
389 clk
->ops
->unprepare(clk
->hw
);
391 __clk_unprepare(clk
->parent
);
395 * clk_unprepare - undo preparation of a clock source
396 * @clk: the clk being unprepare
398 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
399 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
400 * if the operation may sleep. One example is a clk which is accessed over
401 * I2c. In the complex case a clk gate operation may require a fast and a slow
402 * part. It is this reason that clk_unprepare and clk_disable are not mutually
403 * exclusive. In fact clk_disable must be called before clk_unprepare.
405 void clk_unprepare(struct clk
*clk
)
407 mutex_lock(&prepare_lock
);
408 __clk_unprepare(clk
);
409 mutex_unlock(&prepare_lock
);
411 EXPORT_SYMBOL_GPL(clk_unprepare
);
413 int __clk_prepare(struct clk
*clk
)
420 if (clk
->prepare_count
== 0) {
421 ret
= __clk_prepare(clk
->parent
);
425 if (clk
->ops
->prepare
) {
426 ret
= clk
->ops
->prepare(clk
->hw
);
428 __clk_unprepare(clk
->parent
);
434 clk
->prepare_count
++;
440 * clk_prepare - prepare a clock source
441 * @clk: the clk being prepared
443 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
444 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
445 * operation may sleep. One example is a clk which is accessed over I2c. In
446 * the complex case a clk ungate operation may require a fast and a slow part.
447 * It is this reason that clk_prepare and clk_enable are not mutually
448 * exclusive. In fact clk_prepare must be called before clk_enable.
449 * Returns 0 on success, -EERROR otherwise.
451 int clk_prepare(struct clk
*clk
)
455 mutex_lock(&prepare_lock
);
456 ret
= __clk_prepare(clk
);
457 mutex_unlock(&prepare_lock
);
461 EXPORT_SYMBOL_GPL(clk_prepare
);
463 static void __clk_disable(struct clk
*clk
)
468 if (WARN_ON(clk
->enable_count
== 0))
471 if (--clk
->enable_count
> 0)
474 if (clk
->ops
->disable
)
475 clk
->ops
->disable(clk
->hw
);
477 __clk_disable(clk
->parent
);
481 * clk_disable - gate a clock
482 * @clk: the clk being gated
484 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
485 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
486 * clk if the operation is fast and will never sleep. One example is a
487 * SoC-internal clk which is controlled via simple register writes. In the
488 * complex case a clk gate operation may require a fast and a slow part. It is
489 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
490 * In fact clk_disable must be called before clk_unprepare.
492 void clk_disable(struct clk
*clk
)
496 spin_lock_irqsave(&enable_lock
, flags
);
498 spin_unlock_irqrestore(&enable_lock
, flags
);
500 EXPORT_SYMBOL_GPL(clk_disable
);
502 static int __clk_enable(struct clk
*clk
)
509 if (WARN_ON(clk
->prepare_count
== 0))
512 if (clk
->enable_count
== 0) {
513 ret
= __clk_enable(clk
->parent
);
518 if (clk
->ops
->enable
) {
519 ret
= clk
->ops
->enable(clk
->hw
);
521 __clk_disable(clk
->parent
);
532 * clk_enable - ungate a clock
533 * @clk: the clk being ungated
535 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
536 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
537 * if the operation will never sleep. One example is a SoC-internal clk which
538 * is controlled via simple register writes. In the complex case a clk ungate
539 * operation may require a fast and a slow part. It is this reason that
540 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
541 * must be called before clk_enable. Returns 0 on success, -EERROR
544 int clk_enable(struct clk
*clk
)
549 spin_lock_irqsave(&enable_lock
, flags
);
550 ret
= __clk_enable(clk
);
551 spin_unlock_irqrestore(&enable_lock
, flags
);
555 EXPORT_SYMBOL_GPL(clk_enable
);
558 * clk_get_rate - return the rate of clk
559 * @clk: the clk whose rate is being returned
561 * Simply returns the cached rate of the clk. Does not query the hardware. If
562 * clk is NULL then returns 0.
564 unsigned long clk_get_rate(struct clk
*clk
)
568 mutex_lock(&prepare_lock
);
569 rate
= __clk_get_rate(clk
);
570 mutex_unlock(&prepare_lock
);
574 EXPORT_SYMBOL_GPL(clk_get_rate
);
577 * __clk_round_rate - round the given rate for a clk
578 * @clk: round the rate of this clock
580 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
582 unsigned long __clk_round_rate(struct clk
*clk
, unsigned long rate
)
584 unsigned long parent_rate
= 0;
589 if (!clk
->ops
->round_rate
) {
590 if (clk
->flags
& CLK_SET_RATE_PARENT
)
591 return __clk_round_rate(clk
->parent
, rate
);
597 parent_rate
= clk
->parent
->rate
;
599 return clk
->ops
->round_rate(clk
->hw
, rate
, &parent_rate
);
603 * clk_round_rate - round the given rate for a clk
604 * @clk: the clk for which we are rounding a rate
605 * @rate: the rate which is to be rounded
607 * Takes in a rate as input and rounds it to a rate that the clk can actually
608 * use which is then returned. If clk doesn't support round_rate operation
609 * then the parent rate is returned.
611 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
615 mutex_lock(&prepare_lock
);
616 ret
= __clk_round_rate(clk
, rate
);
617 mutex_unlock(&prepare_lock
);
621 EXPORT_SYMBOL_GPL(clk_round_rate
);
624 * __clk_notify - call clk notifier chain
625 * @clk: struct clk * that is changing rate
626 * @msg: clk notifier type (see include/linux/clk.h)
627 * @old_rate: old clk rate
628 * @new_rate: new clk rate
630 * Triggers a notifier call chain on the clk rate-change notification
631 * for 'clk'. Passes a pointer to the struct clk and the previous
632 * and current rates to the notifier callback. Intended to be called by
633 * internal clock code only. Returns NOTIFY_DONE from the last driver
634 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
635 * a driver returns that.
637 static int __clk_notify(struct clk
*clk
, unsigned long msg
,
638 unsigned long old_rate
, unsigned long new_rate
)
640 struct clk_notifier
*cn
;
641 struct clk_notifier_data cnd
;
642 int ret
= NOTIFY_DONE
;
645 cnd
.old_rate
= old_rate
;
646 cnd
.new_rate
= new_rate
;
648 list_for_each_entry(cn
, &clk_notifier_list
, node
) {
649 if (cn
->clk
== clk
) {
650 ret
= srcu_notifier_call_chain(&cn
->notifier_head
, msg
,
661 * @clk: first clk in the subtree
662 * @msg: notification type (see include/linux/clk.h)
664 * Walks the subtree of clks starting with clk and recalculates rates as it
665 * goes. Note that if a clk does not implement the .recalc_rate callback then
666 * it is assumed that the clock will take on the rate of it's parent.
668 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
671 * Caller must hold prepare_lock.
673 static void __clk_recalc_rates(struct clk
*clk
, unsigned long msg
)
675 unsigned long old_rate
;
676 unsigned long parent_rate
= 0;
677 struct hlist_node
*tmp
;
680 old_rate
= clk
->rate
;
683 parent_rate
= clk
->parent
->rate
;
685 if (clk
->ops
->recalc_rate
)
686 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
688 clk
->rate
= parent_rate
;
691 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
692 * & ABORT_RATE_CHANGE notifiers
694 if (clk
->notifier_count
&& msg
)
695 __clk_notify(clk
, msg
, old_rate
, clk
->rate
);
697 hlist_for_each_entry(child
, tmp
, &clk
->children
, child_node
)
698 __clk_recalc_rates(child
, msg
);
702 * __clk_speculate_rates
703 * @clk: first clk in the subtree
704 * @parent_rate: the "future" rate of clk's parent
706 * Walks the subtree of clks starting with clk, speculating rates as it
707 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
709 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
710 * pre-rate change notifications and returns early if no clks in the
711 * subtree have subscribed to the notifications. Note that if a clk does not
712 * implement the .recalc_rate callback then it is assumed that the clock will
713 * take on the rate of it's parent.
715 * Caller must hold prepare_lock.
717 static int __clk_speculate_rates(struct clk
*clk
, unsigned long parent_rate
)
719 struct hlist_node
*tmp
;
721 unsigned long new_rate
;
722 int ret
= NOTIFY_DONE
;
724 if (clk
->ops
->recalc_rate
)
725 new_rate
= clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
727 new_rate
= parent_rate
;
729 /* abort the rate change if a driver returns NOTIFY_BAD */
730 if (clk
->notifier_count
)
731 ret
= __clk_notify(clk
, PRE_RATE_CHANGE
, clk
->rate
, new_rate
);
733 if (ret
== NOTIFY_BAD
)
736 hlist_for_each_entry(child
, tmp
, &clk
->children
, child_node
) {
737 ret
= __clk_speculate_rates(child
, new_rate
);
738 if (ret
== NOTIFY_BAD
)
746 static void clk_calc_subtree(struct clk
*clk
, unsigned long new_rate
)
749 struct hlist_node
*tmp
;
751 clk
->new_rate
= new_rate
;
753 hlist_for_each_entry(child
, tmp
, &clk
->children
, child_node
) {
754 if (child
->ops
->recalc_rate
)
755 child
->new_rate
= child
->ops
->recalc_rate(child
->hw
, new_rate
);
757 child
->new_rate
= new_rate
;
758 clk_calc_subtree(child
, child
->new_rate
);
763 * calculate the new rates returning the topmost clock that has to be
766 static struct clk
*clk_calc_new_rates(struct clk
*clk
, unsigned long rate
)
768 struct clk
*top
= clk
;
769 unsigned long best_parent_rate
= 0;
770 unsigned long new_rate
;
773 if (IS_ERR_OR_NULL(clk
))
776 /* save parent rate, if it exists */
778 best_parent_rate
= clk
->parent
->rate
;
780 /* never propagate up to the parent */
781 if (!(clk
->flags
& CLK_SET_RATE_PARENT
)) {
782 if (!clk
->ops
->round_rate
) {
783 clk
->new_rate
= clk
->rate
;
786 new_rate
= clk
->ops
->round_rate(clk
->hw
, rate
, &best_parent_rate
);
790 /* need clk->parent from here on out */
792 pr_debug("%s: %s has NULL parent\n", __func__
, clk
->name
);
796 if (!clk
->ops
->round_rate
) {
797 top
= clk_calc_new_rates(clk
->parent
, rate
);
798 new_rate
= clk
->parent
->new_rate
;
803 new_rate
= clk
->ops
->round_rate(clk
->hw
, rate
, &best_parent_rate
);
805 if (best_parent_rate
!= clk
->parent
->rate
) {
806 top
= clk_calc_new_rates(clk
->parent
, best_parent_rate
);
812 clk_calc_subtree(clk
, new_rate
);
818 * Notify about rate changes in a subtree. Always walk down the whole tree
819 * so that in case of an error we can walk down the whole tree again and
822 static struct clk
*clk_propagate_rate_change(struct clk
*clk
, unsigned long event
)
824 struct hlist_node
*tmp
;
825 struct clk
*child
, *fail_clk
= NULL
;
826 int ret
= NOTIFY_DONE
;
828 if (clk
->rate
== clk
->new_rate
)
831 if (clk
->notifier_count
) {
832 ret
= __clk_notify(clk
, event
, clk
->rate
, clk
->new_rate
);
833 if (ret
== NOTIFY_BAD
)
837 hlist_for_each_entry(child
, tmp
, &clk
->children
, child_node
) {
838 clk
= clk_propagate_rate_change(child
, event
);
847 * walk down a subtree and set the new rates notifying the rate
850 static void clk_change_rate(struct clk
*clk
)
853 unsigned long old_rate
;
854 unsigned long best_parent_rate
= 0;
855 struct hlist_node
*tmp
;
857 old_rate
= clk
->rate
;
860 best_parent_rate
= clk
->parent
->rate
;
862 if (clk
->ops
->set_rate
)
863 clk
->ops
->set_rate(clk
->hw
, clk
->new_rate
, best_parent_rate
);
865 if (clk
->ops
->recalc_rate
)
866 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
, best_parent_rate
);
868 clk
->rate
= best_parent_rate
;
870 if (clk
->notifier_count
&& old_rate
!= clk
->rate
)
871 __clk_notify(clk
, POST_RATE_CHANGE
, old_rate
, clk
->rate
);
873 hlist_for_each_entry(child
, tmp
, &clk
->children
, child_node
)
874 clk_change_rate(child
);
878 * clk_set_rate - specify a new rate for clk
879 * @clk: the clk whose rate is being changed
880 * @rate: the new rate for clk
882 * In the simplest case clk_set_rate will only adjust the rate of clk.
884 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
885 * propagate up to clk's parent; whether or not this happens depends on the
886 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
887 * after calling .round_rate then upstream parent propagation is ignored. If
888 * *parent_rate comes back with a new rate for clk's parent then we propagate
889 * up to clk's parent and set it's rate. Upward propagation will continue
890 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
891 * .round_rate stops requesting changes to clk's parent_rate.
893 * Rate changes are accomplished via tree traversal that also recalculates the
894 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
896 * Returns 0 on success, -EERROR otherwise.
898 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
900 struct clk
*top
, *fail_clk
;
903 /* prevent racing with updates to the clock topology */
904 mutex_lock(&prepare_lock
);
906 /* bail early if nothing to do */
907 if (rate
== clk
->rate
)
910 if ((clk
->flags
& CLK_SET_RATE_GATE
) && clk
->prepare_count
) {
915 /* calculate new rates and get the topmost changed clock */
916 top
= clk_calc_new_rates(clk
, rate
);
922 /* notify that we are about to change rates */
923 fail_clk
= clk_propagate_rate_change(top
, PRE_RATE_CHANGE
);
925 pr_warn("%s: failed to set %s rate\n", __func__
,
927 clk_propagate_rate_change(top
, ABORT_RATE_CHANGE
);
932 /* change the rates */
933 clk_change_rate(top
);
935 mutex_unlock(&prepare_lock
);
939 mutex_unlock(&prepare_lock
);
943 EXPORT_SYMBOL_GPL(clk_set_rate
);
946 * clk_get_parent - return the parent of a clk
947 * @clk: the clk whose parent gets returned
949 * Simply returns clk->parent. Returns NULL if clk is NULL.
951 struct clk
*clk_get_parent(struct clk
*clk
)
955 mutex_lock(&prepare_lock
);
956 parent
= __clk_get_parent(clk
);
957 mutex_unlock(&prepare_lock
);
961 EXPORT_SYMBOL_GPL(clk_get_parent
);
964 * .get_parent is mandatory for clocks with multiple possible parents. It is
965 * optional for single-parent clocks. Always call .get_parent if it is
966 * available and WARN if it is missing for multi-parent clocks.
968 * For single-parent clocks without .get_parent, first check to see if the
969 * .parents array exists, and if so use it to avoid an expensive tree
970 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
972 static struct clk
*__clk_init_parent(struct clk
*clk
)
974 struct clk
*ret
= NULL
;
977 /* handle the trivial cases */
979 if (!clk
->num_parents
)
982 if (clk
->num_parents
== 1) {
983 if (IS_ERR_OR_NULL(clk
->parent
))
984 ret
= clk
->parent
= __clk_lookup(clk
->parent_names
[0]);
989 if (!clk
->ops
->get_parent
) {
990 WARN(!clk
->ops
->get_parent
,
991 "%s: multi-parent clocks must implement .get_parent\n",
997 * Do our best to cache parent clocks in clk->parents. This prevents
998 * unnecessary and expensive calls to __clk_lookup. We don't set
999 * clk->parent here; that is done by the calling function
1002 index
= clk
->ops
->get_parent(clk
->hw
);
1006 kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1010 ret
= __clk_lookup(clk
->parent_names
[index
]);
1011 else if (!clk
->parents
[index
])
1012 ret
= clk
->parents
[index
] =
1013 __clk_lookup(clk
->parent_names
[index
]);
1015 ret
= clk
->parents
[index
];
1021 void __clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1023 #ifdef CONFIG_COMMON_CLK_DEBUG
1025 struct dentry
*new_parent_d
;
1028 if (!clk
|| !new_parent
)
1031 hlist_del(&clk
->child_node
);
1034 hlist_add_head(&clk
->child_node
, &new_parent
->children
);
1036 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1038 #ifdef CONFIG_COMMON_CLK_DEBUG
1043 new_parent_d
= new_parent
->dentry
;
1045 new_parent_d
= orphandir
;
1047 d
= debugfs_rename(clk
->dentry
->d_parent
, clk
->dentry
,
1048 new_parent_d
, clk
->name
);
1052 pr_debug("%s: failed to rename debugfs entry for %s\n",
1053 __func__
, clk
->name
);
1057 clk
->parent
= new_parent
;
1059 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1062 static int __clk_set_parent(struct clk
*clk
, struct clk
*parent
)
1064 struct clk
*old_parent
;
1065 unsigned long flags
;
1069 old_parent
= clk
->parent
;
1072 clk
->parents
= kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1076 * find index of new parent clock using cached parent ptrs,
1077 * or if not yet cached, use string name comparison and cache
1078 * them now to avoid future calls to __clk_lookup.
1080 for (i
= 0; i
< clk
->num_parents
; i
++) {
1081 if (clk
->parents
&& clk
->parents
[i
] == parent
)
1083 else if (!strcmp(clk
->parent_names
[i
], parent
->name
)) {
1085 clk
->parents
[i
] = __clk_lookup(parent
->name
);
1090 if (i
== clk
->num_parents
) {
1091 pr_debug("%s: clock %s is not a possible parent of clock %s\n",
1092 __func__
, parent
->name
, clk
->name
);
1096 /* migrate prepare and enable */
1097 if (clk
->prepare_count
)
1098 __clk_prepare(parent
);
1100 /* FIXME replace with clk_is_enabled(clk) someday */
1101 spin_lock_irqsave(&enable_lock
, flags
);
1102 if (clk
->enable_count
)
1103 __clk_enable(parent
);
1104 spin_unlock_irqrestore(&enable_lock
, flags
);
1106 /* change clock input source */
1107 ret
= clk
->ops
->set_parent(clk
->hw
, i
);
1109 /* clean up old prepare and enable */
1110 spin_lock_irqsave(&enable_lock
, flags
);
1111 if (clk
->enable_count
)
1112 __clk_disable(old_parent
);
1113 spin_unlock_irqrestore(&enable_lock
, flags
);
1115 if (clk
->prepare_count
)
1116 __clk_unprepare(old_parent
);
1123 * clk_set_parent - switch the parent of a mux clk
1124 * @clk: the mux clk whose input we are switching
1125 * @parent: the new input to clk
1127 * Re-parent clk to use parent as it's new input source. If clk has the
1128 * CLK_SET_PARENT_GATE flag set then clk must be gated for this
1129 * operation to succeed. After successfully changing clk's parent
1130 * clk_set_parent will update the clk topology, sysfs topology and
1131 * propagate rate recalculation via __clk_recalc_rates. Returns 0 on
1132 * success, -EERROR otherwise.
1134 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
1138 if (!clk
|| !clk
->ops
)
1141 if (!clk
->ops
->set_parent
)
1144 /* prevent racing with updates to the clock topology */
1145 mutex_lock(&prepare_lock
);
1147 if (clk
->parent
== parent
)
1150 /* propagate PRE_RATE_CHANGE notifications */
1151 if (clk
->notifier_count
)
1152 ret
= __clk_speculate_rates(clk
, parent
->rate
);
1154 /* abort if a driver objects */
1155 if (ret
== NOTIFY_STOP
)
1158 /* only re-parent if the clock is not in use */
1159 if ((clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
)
1162 ret
= __clk_set_parent(clk
, parent
);
1164 /* propagate ABORT_RATE_CHANGE if .set_parent failed */
1166 __clk_recalc_rates(clk
, ABORT_RATE_CHANGE
);
1170 /* propagate rate recalculation downstream */
1171 __clk_reparent(clk
, parent
);
1174 mutex_unlock(&prepare_lock
);
1178 EXPORT_SYMBOL_GPL(clk_set_parent
);
1181 * __clk_init - initialize the data structures in a struct clk
1182 * @dev: device initializing this clk, placeholder for now
1183 * @clk: clk being initialized
1185 * Initializes the lists in struct clk, queries the hardware for the
1186 * parent and rate and sets them both.
1188 int __clk_init(struct device
*dev
, struct clk
*clk
)
1192 struct hlist_node
*tmp
, *tmp2
;
1197 mutex_lock(&prepare_lock
);
1199 /* check to see if a clock with this name is already registered */
1200 if (__clk_lookup(clk
->name
)) {
1201 pr_debug("%s: clk %s already initialized\n",
1202 __func__
, clk
->name
);
1207 /* check that clk_ops are sane. See Documentation/clk.txt */
1208 if (clk
->ops
->set_rate
&&
1209 !(clk
->ops
->round_rate
&& clk
->ops
->recalc_rate
)) {
1210 pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
1211 __func__
, clk
->name
);
1216 if (clk
->ops
->set_parent
&& !clk
->ops
->get_parent
) {
1217 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1218 __func__
, clk
->name
);
1223 /* throw a WARN if any entries in parent_names are NULL */
1224 for (i
= 0; i
< clk
->num_parents
; i
++)
1225 WARN(!clk
->parent_names
[i
],
1226 "%s: invalid NULL in %s's .parent_names\n",
1227 __func__
, clk
->name
);
1230 * Allocate an array of struct clk *'s to avoid unnecessary string
1231 * look-ups of clk's possible parents. This can fail for clocks passed
1232 * in to clk_init during early boot; thus any access to clk->parents[]
1233 * must always check for a NULL pointer and try to populate it if
1236 * If clk->parents is not NULL we skip this entire block. This allows
1237 * for clock drivers to statically initialize clk->parents.
1239 if (clk
->num_parents
> 1 && !clk
->parents
) {
1240 clk
->parents
= kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1243 * __clk_lookup returns NULL for parents that have not been
1244 * clk_init'd; thus any access to clk->parents[] must check
1245 * for a NULL pointer. We can always perform lazy lookups for
1246 * missing parents later on.
1249 for (i
= 0; i
< clk
->num_parents
; i
++)
1251 __clk_lookup(clk
->parent_names
[i
]);
1254 clk
->parent
= __clk_init_parent(clk
);
1257 * Populate clk->parent if parent has already been __clk_init'd. If
1258 * parent has not yet been __clk_init'd then place clk in the orphan
1259 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1262 * Every time a new clk is clk_init'd then we walk the list of orphan
1263 * clocks and re-parent any that are children of the clock currently
1267 hlist_add_head(&clk
->child_node
,
1268 &clk
->parent
->children
);
1269 else if (clk
->flags
& CLK_IS_ROOT
)
1270 hlist_add_head(&clk
->child_node
, &clk_root_list
);
1272 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1275 * Set clk's rate. The preferred method is to use .recalc_rate. For
1276 * simple clocks and lazy developers the default fallback is to use the
1277 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1278 * then rate is set to zero.
1280 if (clk
->ops
->recalc_rate
)
1281 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
,
1282 __clk_get_rate(clk
->parent
));
1283 else if (clk
->parent
)
1284 clk
->rate
= clk
->parent
->rate
;
1289 * walk the list of orphan clocks and reparent any that are children of
1292 hlist_for_each_entry_safe(orphan
, tmp
, tmp2
, &clk_orphan_list
, child_node
)
1293 for (i
= 0; i
< orphan
->num_parents
; i
++)
1294 if (!strcmp(clk
->name
, orphan
->parent_names
[i
])) {
1295 __clk_reparent(orphan
, clk
);
1300 * optional platform-specific magic
1302 * The .init callback is not used by any of the basic clock types, but
1303 * exists for weird hardware that must perform initialization magic.
1304 * Please consider other ways of solving initialization problems before
1305 * using this callback, as it's use is discouraged.
1308 clk
->ops
->init(clk
->hw
);
1310 clk_debug_register(clk
);
1313 mutex_unlock(&prepare_lock
);
1319 * __clk_register - register a clock and return a cookie.
1321 * Same as clk_register, except that the .clk field inside hw shall point to a
1322 * preallocated (generally statically allocated) struct clk. None of the fields
1323 * of the struct clk need to be initialized.
1325 * The data pointed to by .init and .clk field shall NOT be marked as init
1328 * __clk_register is only exposed via clk-private.h and is intended for use with
1329 * very large numbers of clocks that need to be statically initialized. It is
1330 * a layering violation to include clk-private.h from any code which implements
1331 * a clock's .ops; as such any statically initialized clock data MUST be in a
1332 * separate C file from the logic that implements it's operations. Returns 0
1333 * on success, otherwise an error code.
1335 struct clk
*__clk_register(struct device
*dev
, struct clk_hw
*hw
)
1341 clk
->name
= hw
->init
->name
;
1342 clk
->ops
= hw
->init
->ops
;
1344 clk
->flags
= hw
->init
->flags
;
1345 clk
->parent_names
= hw
->init
->parent_names
;
1346 clk
->num_parents
= hw
->init
->num_parents
;
1348 ret
= __clk_init(dev
, clk
);
1350 return ERR_PTR(ret
);
1354 EXPORT_SYMBOL_GPL(__clk_register
);
1357 * clk_register - allocate a new clock, register it and return an opaque cookie
1358 * @dev: device that is registering this clock
1359 * @hw: link to hardware-specific clock data
1361 * clk_register is the primary interface for populating the clock tree with new
1362 * clock nodes. It returns a pointer to the newly allocated struct clk which
1363 * cannot be dereferenced by driver code but may be used in conjuction with the
1364 * rest of the clock API. In the event of an error clk_register will return an
1365 * error code; drivers must test for an error code after calling clk_register.
1367 struct clk
*clk_register(struct device
*dev
, struct clk_hw
*hw
)
1372 clk
= kzalloc(sizeof(*clk
), GFP_KERNEL
);
1374 pr_err("%s: could not allocate clk\n", __func__
);
1379 clk
->name
= kstrdup(hw
->init
->name
, GFP_KERNEL
);
1381 pr_err("%s: could not allocate clk->name\n", __func__
);
1385 clk
->ops
= hw
->init
->ops
;
1387 clk
->flags
= hw
->init
->flags
;
1388 clk
->num_parents
= hw
->init
->num_parents
;
1391 /* allocate local copy in case parent_names is __initdata */
1392 clk
->parent_names
= kzalloc((sizeof(char*) * clk
->num_parents
),
1395 if (!clk
->parent_names
) {
1396 pr_err("%s: could not allocate clk->parent_names\n", __func__
);
1398 goto fail_parent_names
;
1402 /* copy each string name in case parent_names is __initdata */
1403 for (i
= 0; i
< clk
->num_parents
; i
++) {
1404 clk
->parent_names
[i
] = kstrdup(hw
->init
->parent_names
[i
],
1406 if (!clk
->parent_names
[i
]) {
1407 pr_err("%s: could not copy parent_names\n", __func__
);
1409 goto fail_parent_names_copy
;
1413 ret
= __clk_init(dev
, clk
);
1417 fail_parent_names_copy
:
1419 kfree(clk
->parent_names
[i
]);
1420 kfree(clk
->parent_names
);
1426 return ERR_PTR(ret
);
1428 EXPORT_SYMBOL_GPL(clk_register
);
1431 * clk_unregister - unregister a currently registered clock
1432 * @clk: clock to unregister
1434 * Currently unimplemented.
1436 void clk_unregister(struct clk
*clk
) {}
1437 EXPORT_SYMBOL_GPL(clk_unregister
);
1439 /*** clk rate change notifiers ***/
1442 * clk_notifier_register - add a clk rate change notifier
1443 * @clk: struct clk * to watch
1444 * @nb: struct notifier_block * with callback info
1446 * Request notification when clk's rate changes. This uses an SRCU
1447 * notifier because we want it to block and notifier unregistrations are
1448 * uncommon. The callbacks associated with the notifier must not
1449 * re-enter into the clk framework by calling any top-level clk APIs;
1450 * this will cause a nested prepare_lock mutex.
1452 * Pre-change notifier callbacks will be passed the current, pre-change
1453 * rate of the clk via struct clk_notifier_data.old_rate. The new,
1454 * post-change rate of the clk is passed via struct
1455 * clk_notifier_data.new_rate.
1457 * Post-change notifiers will pass the now-current, post-change rate of
1458 * the clk in both struct clk_notifier_data.old_rate and struct
1459 * clk_notifier_data.new_rate.
1461 * Abort-change notifiers are effectively the opposite of pre-change
1462 * notifiers: the original pre-change clk rate is passed in via struct
1463 * clk_notifier_data.new_rate and the failed post-change rate is passed
1464 * in via struct clk_notifier_data.old_rate.
1466 * clk_notifier_register() must be called from non-atomic context.
1467 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1468 * allocation failure; otherwise, passes along the return value of
1469 * srcu_notifier_chain_register().
1471 int clk_notifier_register(struct clk
*clk
, struct notifier_block
*nb
)
1473 struct clk_notifier
*cn
;
1479 mutex_lock(&prepare_lock
);
1481 /* search the list of notifiers for this clk */
1482 list_for_each_entry(cn
, &clk_notifier_list
, node
)
1486 /* if clk wasn't in the notifier list, allocate new clk_notifier */
1487 if (cn
->clk
!= clk
) {
1488 cn
= kzalloc(sizeof(struct clk_notifier
), GFP_KERNEL
);
1493 srcu_init_notifier_head(&cn
->notifier_head
);
1495 list_add(&cn
->node
, &clk_notifier_list
);
1498 ret
= srcu_notifier_chain_register(&cn
->notifier_head
, nb
);
1500 clk
->notifier_count
++;
1503 mutex_unlock(&prepare_lock
);
1507 EXPORT_SYMBOL_GPL(clk_notifier_register
);
1510 * clk_notifier_unregister - remove a clk rate change notifier
1511 * @clk: struct clk *
1512 * @nb: struct notifier_block * with callback info
1514 * Request no further notification for changes to 'clk' and frees memory
1515 * allocated in clk_notifier_register.
1517 * Returns -EINVAL if called with null arguments; otherwise, passes
1518 * along the return value of srcu_notifier_chain_unregister().
1520 int clk_notifier_unregister(struct clk
*clk
, struct notifier_block
*nb
)
1522 struct clk_notifier
*cn
= NULL
;
1528 mutex_lock(&prepare_lock
);
1530 list_for_each_entry(cn
, &clk_notifier_list
, node
)
1534 if (cn
->clk
== clk
) {
1535 ret
= srcu_notifier_chain_unregister(&cn
->notifier_head
, nb
);
1537 clk
->notifier_count
--;
1539 /* XXX the notifier code should handle this better */
1540 if (!cn
->notifier_head
.head
) {
1541 srcu_cleanup_notifier_head(&cn
->notifier_head
);
1549 mutex_unlock(&prepare_lock
);
1553 EXPORT_SYMBOL_GPL(clk_notifier_unregister
);
1557 * struct of_clk_provider - Clock provider registration structure
1558 * @link: Entry in global list of clock providers
1559 * @node: Pointer to device tree node of clock provider
1560 * @get: Get clock callback. Returns NULL or a struct clk for the
1561 * given clock specifier
1562 * @data: context pointer to be passed into @get callback
1564 struct of_clk_provider
{
1565 struct list_head link
;
1567 struct device_node
*node
;
1568 struct clk
*(*get
)(struct of_phandle_args
*clkspec
, void *data
);
1572 static LIST_HEAD(of_clk_providers
);
1573 static DEFINE_MUTEX(of_clk_lock
);
1575 struct clk
*of_clk_src_simple_get(struct of_phandle_args
*clkspec
,
1580 EXPORT_SYMBOL_GPL(of_clk_src_simple_get
);
1583 * of_clk_add_provider() - Register a clock provider for a node
1584 * @np: Device node pointer associated with clock provider
1585 * @clk_src_get: callback for decoding clock
1586 * @data: context pointer for @clk_src_get callback.
1588 int of_clk_add_provider(struct device_node
*np
,
1589 struct clk
*(*clk_src_get
)(struct of_phandle_args
*clkspec
,
1593 struct of_clk_provider
*cp
;
1595 cp
= kzalloc(sizeof(struct of_clk_provider
), GFP_KERNEL
);
1599 cp
->node
= of_node_get(np
);
1601 cp
->get
= clk_src_get
;
1603 mutex_lock(&of_clk_lock
);
1604 list_add(&cp
->link
, &of_clk_providers
);
1605 mutex_unlock(&of_clk_lock
);
1606 pr_debug("Added clock from %s\n", np
->full_name
);
1610 EXPORT_SYMBOL_GPL(of_clk_add_provider
);
1613 * of_clk_del_provider() - Remove a previously registered clock provider
1614 * @np: Device node pointer associated with clock provider
1616 void of_clk_del_provider(struct device_node
*np
)
1618 struct of_clk_provider
*cp
;
1620 mutex_lock(&of_clk_lock
);
1621 list_for_each_entry(cp
, &of_clk_providers
, link
) {
1622 if (cp
->node
== np
) {
1623 list_del(&cp
->link
);
1624 of_node_put(cp
->node
);
1629 mutex_unlock(&of_clk_lock
);
1631 EXPORT_SYMBOL_GPL(of_clk_del_provider
);
1633 struct clk
*of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
1635 struct of_clk_provider
*provider
;
1636 struct clk
*clk
= ERR_PTR(-ENOENT
);
1638 /* Check if we have such a provider in our array */
1639 mutex_lock(&of_clk_lock
);
1640 list_for_each_entry(provider
, &of_clk_providers
, link
) {
1641 if (provider
->node
== clkspec
->np
)
1642 clk
= provider
->get(clkspec
, provider
->data
);
1646 mutex_unlock(&of_clk_lock
);
1651 const char *of_clk_get_parent_name(struct device_node
*np
, int index
)
1653 struct of_phandle_args clkspec
;
1654 const char *clk_name
;
1660 rc
= of_parse_phandle_with_args(np
, "clocks", "#clock-cells", index
,
1665 if (of_property_read_string_index(clkspec
.np
, "clock-output-names",
1666 clkspec
.args_count
? clkspec
.args
[0] : 0,
1668 clk_name
= clkspec
.np
->name
;
1670 of_node_put(clkspec
.np
);
1673 EXPORT_SYMBOL_GPL(of_clk_get_parent_name
);
1676 * of_clk_init() - Scan and init clock providers from the DT
1677 * @matches: array of compatible values and init functions for providers.
1679 * This function scans the device tree for matching clock providers and
1680 * calls their initialization functions
1682 void __init
of_clk_init(const struct of_device_id
*matches
)
1684 struct device_node
*np
;
1686 for_each_matching_node(np
, matches
) {
1687 const struct of_device_id
*match
= of_match_node(matches
, np
);
1688 of_clk_init_cb_t clk_init_cb
= match
->data
;