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-provider.h>
13 #include <linux/clk/clk-conf.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/spinlock.h>
17 #include <linux/err.h>
18 #include <linux/list.h>
19 #include <linux/slab.h>
21 #include <linux/device.h>
22 #include <linux/init.h>
23 #include <linux/sched.h>
24 #include <linux/clkdev.h>
28 static DEFINE_SPINLOCK(enable_lock
);
29 static DEFINE_MUTEX(prepare_lock
);
31 static struct task_struct
*prepare_owner
;
32 static struct task_struct
*enable_owner
;
34 static int prepare_refcnt
;
35 static int enable_refcnt
;
37 static HLIST_HEAD(clk_root_list
);
38 static HLIST_HEAD(clk_orphan_list
);
39 static LIST_HEAD(clk_notifier_list
);
41 /*** private data structures ***/
45 const struct clk_ops
*ops
;
48 struct clk_core
*parent
;
49 const char **parent_names
;
50 struct clk_core
**parents
;
54 unsigned long req_rate
;
55 unsigned long new_rate
;
56 struct clk_core
*new_parent
;
57 struct clk_core
*new_child
;
59 unsigned int enable_count
;
60 unsigned int prepare_count
;
61 unsigned long accuracy
;
63 struct hlist_head children
;
64 struct hlist_node child_node
;
65 struct hlist_head clks
;
66 unsigned int notifier_count
;
67 #ifdef CONFIG_DEBUG_FS
68 struct dentry
*dentry
;
69 struct hlist_node debug_node
;
74 #define CREATE_TRACE_POINTS
75 #include <trace/events/clk.h>
78 struct clk_core
*core
;
81 unsigned long min_rate
;
82 unsigned long max_rate
;
83 struct hlist_node clks_node
;
87 static void clk_prepare_lock(void)
89 if (!mutex_trylock(&prepare_lock
)) {
90 if (prepare_owner
== current
) {
94 mutex_lock(&prepare_lock
);
96 WARN_ON_ONCE(prepare_owner
!= NULL
);
97 WARN_ON_ONCE(prepare_refcnt
!= 0);
98 prepare_owner
= current
;
102 static void clk_prepare_unlock(void)
104 WARN_ON_ONCE(prepare_owner
!= current
);
105 WARN_ON_ONCE(prepare_refcnt
== 0);
107 if (--prepare_refcnt
)
109 prepare_owner
= NULL
;
110 mutex_unlock(&prepare_lock
);
113 static unsigned long clk_enable_lock(void)
117 if (!spin_trylock_irqsave(&enable_lock
, flags
)) {
118 if (enable_owner
== current
) {
122 spin_lock_irqsave(&enable_lock
, flags
);
124 WARN_ON_ONCE(enable_owner
!= NULL
);
125 WARN_ON_ONCE(enable_refcnt
!= 0);
126 enable_owner
= current
;
131 static void clk_enable_unlock(unsigned long flags
)
133 WARN_ON_ONCE(enable_owner
!= current
);
134 WARN_ON_ONCE(enable_refcnt
== 0);
139 spin_unlock_irqrestore(&enable_lock
, flags
);
142 static bool clk_core_is_prepared(struct clk_core
*core
)
145 * .is_prepared is optional for clocks that can prepare
146 * fall back to software usage counter if it is missing
148 if (!core
->ops
->is_prepared
)
149 return core
->prepare_count
;
151 return core
->ops
->is_prepared(core
->hw
);
154 static bool clk_core_is_enabled(struct clk_core
*core
)
157 * .is_enabled is only mandatory for clocks that gate
158 * fall back to software usage counter if .is_enabled is missing
160 if (!core
->ops
->is_enabled
)
161 return core
->enable_count
;
163 return core
->ops
->is_enabled(core
->hw
);
166 static void clk_unprepare_unused_subtree(struct clk_core
*core
)
168 struct clk_core
*child
;
170 lockdep_assert_held(&prepare_lock
);
172 hlist_for_each_entry(child
, &core
->children
, child_node
)
173 clk_unprepare_unused_subtree(child
);
175 if (core
->prepare_count
)
178 if (core
->flags
& CLK_IGNORE_UNUSED
)
181 if (clk_core_is_prepared(core
)) {
182 trace_clk_unprepare(core
);
183 if (core
->ops
->unprepare_unused
)
184 core
->ops
->unprepare_unused(core
->hw
);
185 else if (core
->ops
->unprepare
)
186 core
->ops
->unprepare(core
->hw
);
187 trace_clk_unprepare_complete(core
);
191 static void clk_disable_unused_subtree(struct clk_core
*core
)
193 struct clk_core
*child
;
196 lockdep_assert_held(&prepare_lock
);
198 hlist_for_each_entry(child
, &core
->children
, child_node
)
199 clk_disable_unused_subtree(child
);
201 flags
= clk_enable_lock();
203 if (core
->enable_count
)
206 if (core
->flags
& CLK_IGNORE_UNUSED
)
210 * some gate clocks have special needs during the disable-unused
211 * sequence. call .disable_unused if available, otherwise fall
214 if (clk_core_is_enabled(core
)) {
215 trace_clk_disable(core
);
216 if (core
->ops
->disable_unused
)
217 core
->ops
->disable_unused(core
->hw
);
218 else if (core
->ops
->disable
)
219 core
->ops
->disable(core
->hw
);
220 trace_clk_disable_complete(core
);
224 clk_enable_unlock(flags
);
227 static bool clk_ignore_unused
;
228 static int __init
clk_ignore_unused_setup(char *__unused
)
230 clk_ignore_unused
= true;
233 __setup("clk_ignore_unused", clk_ignore_unused_setup
);
235 static int clk_disable_unused(void)
237 struct clk_core
*core
;
239 if (clk_ignore_unused
) {
240 pr_warn("clk: Not disabling unused clocks\n");
246 hlist_for_each_entry(core
, &clk_root_list
, child_node
)
247 clk_disable_unused_subtree(core
);
249 hlist_for_each_entry(core
, &clk_orphan_list
, child_node
)
250 clk_disable_unused_subtree(core
);
252 hlist_for_each_entry(core
, &clk_root_list
, child_node
)
253 clk_unprepare_unused_subtree(core
);
255 hlist_for_each_entry(core
, &clk_orphan_list
, child_node
)
256 clk_unprepare_unused_subtree(core
);
258 clk_prepare_unlock();
262 late_initcall_sync(clk_disable_unused
);
264 /*** helper functions ***/
266 const char *__clk_get_name(struct clk
*clk
)
268 return !clk
? NULL
: clk
->core
->name
;
270 EXPORT_SYMBOL_GPL(__clk_get_name
);
272 struct clk_hw
*__clk_get_hw(struct clk
*clk
)
274 return !clk
? NULL
: clk
->core
->hw
;
276 EXPORT_SYMBOL_GPL(__clk_get_hw
);
278 u8
__clk_get_num_parents(struct clk
*clk
)
280 return !clk
? 0 : clk
->core
->num_parents
;
282 EXPORT_SYMBOL_GPL(__clk_get_num_parents
);
284 struct clk
*__clk_get_parent(struct clk
*clk
)
289 /* TODO: Create a per-user clk and change callers to call clk_put */
290 return !clk
->core
->parent
? NULL
: clk
->core
->parent
->hw
->clk
;
292 EXPORT_SYMBOL_GPL(__clk_get_parent
);
294 static struct clk_core
*__clk_lookup_subtree(const char *name
,
295 struct clk_core
*core
)
297 struct clk_core
*child
;
298 struct clk_core
*ret
;
300 if (!strcmp(core
->name
, name
))
303 hlist_for_each_entry(child
, &core
->children
, child_node
) {
304 ret
= __clk_lookup_subtree(name
, child
);
312 static struct clk_core
*clk_core_lookup(const char *name
)
314 struct clk_core
*root_clk
;
315 struct clk_core
*ret
;
320 /* search the 'proper' clk tree first */
321 hlist_for_each_entry(root_clk
, &clk_root_list
, child_node
) {
322 ret
= __clk_lookup_subtree(name
, root_clk
);
327 /* if not found, then search the orphan tree */
328 hlist_for_each_entry(root_clk
, &clk_orphan_list
, child_node
) {
329 ret
= __clk_lookup_subtree(name
, root_clk
);
337 static struct clk_core
*clk_core_get_parent_by_index(struct clk_core
*core
,
340 if (!core
|| index
>= core
->num_parents
)
342 else if (!core
->parents
)
343 return clk_core_lookup(core
->parent_names
[index
]);
344 else if (!core
->parents
[index
])
345 return core
->parents
[index
] =
346 clk_core_lookup(core
->parent_names
[index
]);
348 return core
->parents
[index
];
351 struct clk
*clk_get_parent_by_index(struct clk
*clk
, u8 index
)
353 struct clk_core
*parent
;
358 parent
= clk_core_get_parent_by_index(clk
->core
, index
);
360 return !parent
? NULL
: parent
->hw
->clk
;
362 EXPORT_SYMBOL_GPL(clk_get_parent_by_index
);
364 unsigned int __clk_get_enable_count(struct clk
*clk
)
366 return !clk
? 0 : clk
->core
->enable_count
;
369 static unsigned long clk_core_get_rate_nolock(struct clk_core
*core
)
380 if (core
->flags
& CLK_IS_ROOT
)
390 unsigned long __clk_get_rate(struct clk
*clk
)
395 return clk_core_get_rate_nolock(clk
->core
);
397 EXPORT_SYMBOL_GPL(__clk_get_rate
);
399 static unsigned long __clk_get_accuracy(struct clk_core
*core
)
404 return core
->accuracy
;
407 unsigned long __clk_get_flags(struct clk
*clk
)
409 return !clk
? 0 : clk
->core
->flags
;
411 EXPORT_SYMBOL_GPL(__clk_get_flags
);
413 bool __clk_is_prepared(struct clk
*clk
)
418 return clk_core_is_prepared(clk
->core
);
421 bool __clk_is_enabled(struct clk
*clk
)
426 return clk_core_is_enabled(clk
->core
);
428 EXPORT_SYMBOL_GPL(__clk_is_enabled
);
430 static bool mux_is_better_rate(unsigned long rate
, unsigned long now
,
431 unsigned long best
, unsigned long flags
)
433 if (flags
& CLK_MUX_ROUND_CLOSEST
)
434 return abs(now
- rate
) < abs(best
- rate
);
436 return now
<= rate
&& now
> best
;
440 clk_mux_determine_rate_flags(struct clk_hw
*hw
, struct clk_rate_request
*req
,
443 struct clk_core
*core
= hw
->core
, *parent
, *best_parent
= NULL
;
444 int i
, num_parents
, ret
;
445 unsigned long best
= 0;
446 struct clk_rate_request parent_req
= *req
;
448 /* if NO_REPARENT flag set, pass through to current parent */
449 if (core
->flags
& CLK_SET_RATE_NO_REPARENT
) {
450 parent
= core
->parent
;
451 if (core
->flags
& CLK_SET_RATE_PARENT
) {
452 ret
= __clk_determine_rate(parent
? parent
->hw
: NULL
,
457 best
= parent_req
.rate
;
459 best
= clk_core_get_rate_nolock(parent
);
461 best
= clk_core_get_rate_nolock(core
);
467 /* find the parent that can provide the fastest rate <= rate */
468 num_parents
= core
->num_parents
;
469 for (i
= 0; i
< num_parents
; i
++) {
470 parent
= clk_core_get_parent_by_index(core
, i
);
474 if (core
->flags
& CLK_SET_RATE_PARENT
) {
476 ret
= __clk_determine_rate(parent
->hw
, &parent_req
);
480 parent_req
.rate
= clk_core_get_rate_nolock(parent
);
483 if (mux_is_better_rate(req
->rate
, parent_req
.rate
,
485 best_parent
= parent
;
486 best
= parent_req
.rate
;
492 req
->best_parent_hw
= best_parent
->hw
;
493 req
->best_parent_rate
= best
;
499 struct clk
*__clk_lookup(const char *name
)
501 struct clk_core
*core
= clk_core_lookup(name
);
503 return !core
? NULL
: core
->hw
->clk
;
506 static void clk_core_get_boundaries(struct clk_core
*core
,
507 unsigned long *min_rate
,
508 unsigned long *max_rate
)
510 struct clk
*clk_user
;
513 *max_rate
= ULONG_MAX
;
515 hlist_for_each_entry(clk_user
, &core
->clks
, clks_node
)
516 *min_rate
= max(*min_rate
, clk_user
->min_rate
);
518 hlist_for_each_entry(clk_user
, &core
->clks
, clks_node
)
519 *max_rate
= min(*max_rate
, clk_user
->max_rate
);
523 * Helper for finding best parent to provide a given frequency. This can be used
524 * directly as a determine_rate callback (e.g. for a mux), or from a more
525 * complex clock that may combine a mux with other operations.
527 int __clk_mux_determine_rate(struct clk_hw
*hw
,
528 struct clk_rate_request
*req
)
530 return clk_mux_determine_rate_flags(hw
, req
, 0);
532 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate
);
534 int __clk_mux_determine_rate_closest(struct clk_hw
*hw
,
535 struct clk_rate_request
*req
)
537 return clk_mux_determine_rate_flags(hw
, req
, CLK_MUX_ROUND_CLOSEST
);
539 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest
);
543 static void clk_core_unprepare(struct clk_core
*core
)
545 lockdep_assert_held(&prepare_lock
);
550 if (WARN_ON(core
->prepare_count
== 0))
553 if (--core
->prepare_count
> 0)
556 WARN_ON(core
->enable_count
> 0);
558 trace_clk_unprepare(core
);
560 if (core
->ops
->unprepare
)
561 core
->ops
->unprepare(core
->hw
);
563 trace_clk_unprepare_complete(core
);
564 clk_core_unprepare(core
->parent
);
568 * clk_unprepare - undo preparation of a clock source
569 * @clk: the clk being unprepared
571 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
572 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
573 * if the operation may sleep. One example is a clk which is accessed over
574 * I2c. In the complex case a clk gate operation may require a fast and a slow
575 * part. It is this reason that clk_unprepare and clk_disable are not mutually
576 * exclusive. In fact clk_disable must be called before clk_unprepare.
578 void clk_unprepare(struct clk
*clk
)
580 if (IS_ERR_OR_NULL(clk
))
584 clk_core_unprepare(clk
->core
);
585 clk_prepare_unlock();
587 EXPORT_SYMBOL_GPL(clk_unprepare
);
589 static int clk_core_prepare(struct clk_core
*core
)
593 lockdep_assert_held(&prepare_lock
);
598 if (core
->prepare_count
== 0) {
599 ret
= clk_core_prepare(core
->parent
);
603 trace_clk_prepare(core
);
605 if (core
->ops
->prepare
)
606 ret
= core
->ops
->prepare(core
->hw
);
608 trace_clk_prepare_complete(core
);
611 clk_core_unprepare(core
->parent
);
616 core
->prepare_count
++;
622 * clk_prepare - prepare a clock source
623 * @clk: the clk being prepared
625 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
626 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
627 * operation may sleep. One example is a clk which is accessed over I2c. In
628 * the complex case a clk ungate operation may require a fast and a slow part.
629 * It is this reason that clk_prepare and clk_enable are not mutually
630 * exclusive. In fact clk_prepare must be called before clk_enable.
631 * Returns 0 on success, -EERROR otherwise.
633 int clk_prepare(struct clk
*clk
)
641 ret
= clk_core_prepare(clk
->core
);
642 clk_prepare_unlock();
646 EXPORT_SYMBOL_GPL(clk_prepare
);
648 static void clk_core_disable(struct clk_core
*core
)
650 lockdep_assert_held(&enable_lock
);
655 if (WARN_ON(core
->enable_count
== 0))
658 if (--core
->enable_count
> 0)
661 trace_clk_disable(core
);
663 if (core
->ops
->disable
)
664 core
->ops
->disable(core
->hw
);
666 trace_clk_disable_complete(core
);
668 clk_core_disable(core
->parent
);
672 * clk_disable - gate a clock
673 * @clk: the clk being gated
675 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
676 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
677 * clk if the operation is fast and will never sleep. One example is a
678 * SoC-internal clk which is controlled via simple register writes. In the
679 * complex case a clk gate operation may require a fast and a slow part. It is
680 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
681 * In fact clk_disable must be called before clk_unprepare.
683 void clk_disable(struct clk
*clk
)
687 if (IS_ERR_OR_NULL(clk
))
690 flags
= clk_enable_lock();
691 clk_core_disable(clk
->core
);
692 clk_enable_unlock(flags
);
694 EXPORT_SYMBOL_GPL(clk_disable
);
696 static int clk_core_enable(struct clk_core
*core
)
700 lockdep_assert_held(&enable_lock
);
705 if (WARN_ON(core
->prepare_count
== 0))
708 if (core
->enable_count
== 0) {
709 ret
= clk_core_enable(core
->parent
);
714 trace_clk_enable(core
);
716 if (core
->ops
->enable
)
717 ret
= core
->ops
->enable(core
->hw
);
719 trace_clk_enable_complete(core
);
722 clk_core_disable(core
->parent
);
727 core
->enable_count
++;
732 * clk_enable - ungate a clock
733 * @clk: the clk being ungated
735 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
736 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
737 * if the operation will never sleep. One example is a SoC-internal clk which
738 * is controlled via simple register writes. In the complex case a clk ungate
739 * operation may require a fast and a slow part. It is this reason that
740 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
741 * must be called before clk_enable. Returns 0 on success, -EERROR
744 int clk_enable(struct clk
*clk
)
752 flags
= clk_enable_lock();
753 ret
= clk_core_enable(clk
->core
);
754 clk_enable_unlock(flags
);
758 EXPORT_SYMBOL_GPL(clk_enable
);
760 static int clk_core_round_rate_nolock(struct clk_core
*core
,
761 struct clk_rate_request
*req
)
763 struct clk_core
*parent
;
766 lockdep_assert_held(&prepare_lock
);
771 parent
= core
->parent
;
773 req
->best_parent_hw
= parent
->hw
;
774 req
->best_parent_rate
= parent
->rate
;
776 req
->best_parent_hw
= NULL
;
777 req
->best_parent_rate
= 0;
780 if (core
->ops
->determine_rate
) {
781 return core
->ops
->determine_rate(core
->hw
, req
);
782 } else if (core
->ops
->round_rate
) {
783 rate
= core
->ops
->round_rate(core
->hw
, req
->rate
,
784 &req
->best_parent_rate
);
789 } else if (core
->flags
& CLK_SET_RATE_PARENT
) {
790 return clk_core_round_rate_nolock(parent
, req
);
792 req
->rate
= core
->rate
;
799 * __clk_determine_rate - get the closest rate actually supported by a clock
800 * @hw: determine the rate of this clock
802 * @min_rate: returned rate must be greater than this rate
803 * @max_rate: returned rate must be less than this rate
805 * Useful for clk_ops such as .set_rate and .determine_rate.
807 int __clk_determine_rate(struct clk_hw
*hw
, struct clk_rate_request
*req
)
814 return clk_core_round_rate_nolock(hw
->core
, req
);
816 EXPORT_SYMBOL_GPL(__clk_determine_rate
);
819 * __clk_round_rate - round the given rate for a clk
820 * @clk: round the rate of this clock
821 * @rate: the rate which is to be rounded
823 * Useful for clk_ops such as .set_rate
825 unsigned long __clk_round_rate(struct clk
*clk
, unsigned long rate
)
827 struct clk_rate_request req
;
833 clk_core_get_boundaries(clk
->core
, &req
.min_rate
, &req
.max_rate
);
836 ret
= clk_core_round_rate_nolock(clk
->core
, &req
);
842 EXPORT_SYMBOL_GPL(__clk_round_rate
);
845 * clk_round_rate - round the given rate for a clk
846 * @clk: the clk for which we are rounding a rate
847 * @rate: the rate which is to be rounded
849 * Takes in a rate as input and rounds it to a rate that the clk can actually
850 * use which is then returned. If clk doesn't support round_rate operation
851 * then the parent rate is returned.
853 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
861 ret
= __clk_round_rate(clk
, rate
);
862 clk_prepare_unlock();
866 EXPORT_SYMBOL_GPL(clk_round_rate
);
869 * __clk_notify - call clk notifier chain
870 * @core: clk that is changing rate
871 * @msg: clk notifier type (see include/linux/clk.h)
872 * @old_rate: old clk rate
873 * @new_rate: new clk rate
875 * Triggers a notifier call chain on the clk rate-change notification
876 * for 'clk'. Passes a pointer to the struct clk and the previous
877 * and current rates to the notifier callback. Intended to be called by
878 * internal clock code only. Returns NOTIFY_DONE from the last driver
879 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
880 * a driver returns that.
882 static int __clk_notify(struct clk_core
*core
, unsigned long msg
,
883 unsigned long old_rate
, unsigned long new_rate
)
885 struct clk_notifier
*cn
;
886 struct clk_notifier_data cnd
;
887 int ret
= NOTIFY_DONE
;
889 cnd
.old_rate
= old_rate
;
890 cnd
.new_rate
= new_rate
;
892 list_for_each_entry(cn
, &clk_notifier_list
, node
) {
893 if (cn
->clk
->core
== core
) {
895 ret
= srcu_notifier_call_chain(&cn
->notifier_head
, msg
,
904 * __clk_recalc_accuracies
905 * @core: first clk in the subtree
907 * Walks the subtree of clks starting with clk and recalculates accuracies as
908 * it goes. Note that if a clk does not implement the .recalc_accuracy
909 * callback then it is assumed that the clock will take on the accuracy of its
912 static void __clk_recalc_accuracies(struct clk_core
*core
)
914 unsigned long parent_accuracy
= 0;
915 struct clk_core
*child
;
917 lockdep_assert_held(&prepare_lock
);
920 parent_accuracy
= core
->parent
->accuracy
;
922 if (core
->ops
->recalc_accuracy
)
923 core
->accuracy
= core
->ops
->recalc_accuracy(core
->hw
,
926 core
->accuracy
= parent_accuracy
;
928 hlist_for_each_entry(child
, &core
->children
, child_node
)
929 __clk_recalc_accuracies(child
);
932 static long clk_core_get_accuracy(struct clk_core
*core
)
934 unsigned long accuracy
;
937 if (core
&& (core
->flags
& CLK_GET_ACCURACY_NOCACHE
))
938 __clk_recalc_accuracies(core
);
940 accuracy
= __clk_get_accuracy(core
);
941 clk_prepare_unlock();
947 * clk_get_accuracy - return the accuracy of clk
948 * @clk: the clk whose accuracy is being returned
950 * Simply returns the cached accuracy of the clk, unless
951 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
953 * If clk is NULL then returns 0.
955 long clk_get_accuracy(struct clk
*clk
)
960 return clk_core_get_accuracy(clk
->core
);
962 EXPORT_SYMBOL_GPL(clk_get_accuracy
);
964 static unsigned long clk_recalc(struct clk_core
*core
,
965 unsigned long parent_rate
)
967 if (core
->ops
->recalc_rate
)
968 return core
->ops
->recalc_rate(core
->hw
, parent_rate
);
974 * @core: first clk in the subtree
975 * @msg: notification type (see include/linux/clk.h)
977 * Walks the subtree of clks starting with clk and recalculates rates as it
978 * goes. Note that if a clk does not implement the .recalc_rate callback then
979 * it is assumed that the clock will take on the rate of its parent.
981 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
984 static void __clk_recalc_rates(struct clk_core
*core
, unsigned long msg
)
986 unsigned long old_rate
;
987 unsigned long parent_rate
= 0;
988 struct clk_core
*child
;
990 lockdep_assert_held(&prepare_lock
);
992 old_rate
= core
->rate
;
995 parent_rate
= core
->parent
->rate
;
997 core
->rate
= clk_recalc(core
, parent_rate
);
1000 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1001 * & ABORT_RATE_CHANGE notifiers
1003 if (core
->notifier_count
&& msg
)
1004 __clk_notify(core
, msg
, old_rate
, core
->rate
);
1006 hlist_for_each_entry(child
, &core
->children
, child_node
)
1007 __clk_recalc_rates(child
, msg
);
1010 static unsigned long clk_core_get_rate(struct clk_core
*core
)
1016 if (core
&& (core
->flags
& CLK_GET_RATE_NOCACHE
))
1017 __clk_recalc_rates(core
, 0);
1019 rate
= clk_core_get_rate_nolock(core
);
1020 clk_prepare_unlock();
1026 * clk_get_rate - return the rate of clk
1027 * @clk: the clk whose rate is being returned
1029 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1030 * is set, which means a recalc_rate will be issued.
1031 * If clk is NULL then returns 0.
1033 unsigned long clk_get_rate(struct clk
*clk
)
1038 return clk_core_get_rate(clk
->core
);
1040 EXPORT_SYMBOL_GPL(clk_get_rate
);
1042 static int clk_fetch_parent_index(struct clk_core
*core
,
1043 struct clk_core
*parent
)
1047 if (!core
->parents
) {
1048 core
->parents
= kcalloc(core
->num_parents
,
1049 sizeof(struct clk
*), GFP_KERNEL
);
1055 * find index of new parent clock using cached parent ptrs,
1056 * or if not yet cached, use string name comparison and cache
1057 * them now to avoid future calls to clk_core_lookup.
1059 for (i
= 0; i
< core
->num_parents
; i
++) {
1060 if (core
->parents
[i
] == parent
)
1063 if (core
->parents
[i
])
1066 if (!strcmp(core
->parent_names
[i
], parent
->name
)) {
1067 core
->parents
[i
] = clk_core_lookup(parent
->name
);
1075 static void clk_reparent(struct clk_core
*core
, struct clk_core
*new_parent
)
1077 hlist_del(&core
->child_node
);
1080 /* avoid duplicate POST_RATE_CHANGE notifications */
1081 if (new_parent
->new_child
== core
)
1082 new_parent
->new_child
= NULL
;
1084 hlist_add_head(&core
->child_node
, &new_parent
->children
);
1086 hlist_add_head(&core
->child_node
, &clk_orphan_list
);
1089 core
->parent
= new_parent
;
1092 static struct clk_core
*__clk_set_parent_before(struct clk_core
*core
,
1093 struct clk_core
*parent
)
1095 unsigned long flags
;
1096 struct clk_core
*old_parent
= core
->parent
;
1099 * Migrate prepare state between parents and prevent race with
1102 * If the clock is not prepared, then a race with
1103 * clk_enable/disable() is impossible since we already have the
1104 * prepare lock (future calls to clk_enable() need to be preceded by
1107 * If the clock is prepared, migrate the prepared state to the new
1108 * parent and also protect against a race with clk_enable() by
1109 * forcing the clock and the new parent on. This ensures that all
1110 * future calls to clk_enable() are practically NOPs with respect to
1111 * hardware and software states.
1113 * See also: Comment for clk_set_parent() below.
1115 if (core
->prepare_count
) {
1116 clk_core_prepare(parent
);
1117 flags
= clk_enable_lock();
1118 clk_core_enable(parent
);
1119 clk_core_enable(core
);
1120 clk_enable_unlock(flags
);
1123 /* update the clk tree topology */
1124 flags
= clk_enable_lock();
1125 clk_reparent(core
, parent
);
1126 clk_enable_unlock(flags
);
1131 static void __clk_set_parent_after(struct clk_core
*core
,
1132 struct clk_core
*parent
,
1133 struct clk_core
*old_parent
)
1135 unsigned long flags
;
1138 * Finish the migration of prepare state and undo the changes done
1139 * for preventing a race with clk_enable().
1141 if (core
->prepare_count
) {
1142 flags
= clk_enable_lock();
1143 clk_core_disable(core
);
1144 clk_core_disable(old_parent
);
1145 clk_enable_unlock(flags
);
1146 clk_core_unprepare(old_parent
);
1150 static int __clk_set_parent(struct clk_core
*core
, struct clk_core
*parent
,
1153 unsigned long flags
;
1155 struct clk_core
*old_parent
;
1157 old_parent
= __clk_set_parent_before(core
, parent
);
1159 trace_clk_set_parent(core
, parent
);
1161 /* change clock input source */
1162 if (parent
&& core
->ops
->set_parent
)
1163 ret
= core
->ops
->set_parent(core
->hw
, p_index
);
1165 trace_clk_set_parent_complete(core
, parent
);
1168 flags
= clk_enable_lock();
1169 clk_reparent(core
, old_parent
);
1170 clk_enable_unlock(flags
);
1172 if (core
->prepare_count
) {
1173 flags
= clk_enable_lock();
1174 clk_core_disable(core
);
1175 clk_core_disable(parent
);
1176 clk_enable_unlock(flags
);
1177 clk_core_unprepare(parent
);
1182 __clk_set_parent_after(core
, parent
, old_parent
);
1188 * __clk_speculate_rates
1189 * @core: first clk in the subtree
1190 * @parent_rate: the "future" rate of clk's parent
1192 * Walks the subtree of clks starting with clk, speculating rates as it
1193 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1195 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1196 * pre-rate change notifications and returns early if no clks in the
1197 * subtree have subscribed to the notifications. Note that if a clk does not
1198 * implement the .recalc_rate callback then it is assumed that the clock will
1199 * take on the rate of its parent.
1201 static int __clk_speculate_rates(struct clk_core
*core
,
1202 unsigned long parent_rate
)
1204 struct clk_core
*child
;
1205 unsigned long new_rate
;
1206 int ret
= NOTIFY_DONE
;
1208 lockdep_assert_held(&prepare_lock
);
1210 new_rate
= clk_recalc(core
, parent_rate
);
1212 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1213 if (core
->notifier_count
)
1214 ret
= __clk_notify(core
, PRE_RATE_CHANGE
, core
->rate
, new_rate
);
1216 if (ret
& NOTIFY_STOP_MASK
) {
1217 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1218 __func__
, core
->name
, ret
);
1222 hlist_for_each_entry(child
, &core
->children
, child_node
) {
1223 ret
= __clk_speculate_rates(child
, new_rate
);
1224 if (ret
& NOTIFY_STOP_MASK
)
1232 static void clk_calc_subtree(struct clk_core
*core
, unsigned long new_rate
,
1233 struct clk_core
*new_parent
, u8 p_index
)
1235 struct clk_core
*child
;
1237 core
->new_rate
= new_rate
;
1238 core
->new_parent
= new_parent
;
1239 core
->new_parent_index
= p_index
;
1240 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1241 core
->new_child
= NULL
;
1242 if (new_parent
&& new_parent
!= core
->parent
)
1243 new_parent
->new_child
= core
;
1245 hlist_for_each_entry(child
, &core
->children
, child_node
) {
1246 child
->new_rate
= clk_recalc(child
, new_rate
);
1247 clk_calc_subtree(child
, child
->new_rate
, NULL
, 0);
1252 * calculate the new rates returning the topmost clock that has to be
1255 static struct clk_core
*clk_calc_new_rates(struct clk_core
*core
,
1258 struct clk_core
*top
= core
;
1259 struct clk_core
*old_parent
, *parent
;
1260 unsigned long best_parent_rate
= 0;
1261 unsigned long new_rate
;
1262 unsigned long min_rate
;
1263 unsigned long max_rate
;
1268 if (IS_ERR_OR_NULL(core
))
1271 /* save parent rate, if it exists */
1272 parent
= old_parent
= core
->parent
;
1274 best_parent_rate
= parent
->rate
;
1276 clk_core_get_boundaries(core
, &min_rate
, &max_rate
);
1278 /* find the closest rate and parent clk/rate */
1279 if (core
->ops
->determine_rate
) {
1280 struct clk_rate_request req
;
1283 req
.min_rate
= min_rate
;
1284 req
.max_rate
= max_rate
;
1286 req
.best_parent_hw
= parent
->hw
;
1287 req
.best_parent_rate
= parent
->rate
;
1289 req
.best_parent_hw
= NULL
;
1290 req
.best_parent_rate
= 0;
1293 ret
= core
->ops
->determine_rate(core
->hw
, &req
);
1297 best_parent_rate
= req
.best_parent_rate
;
1298 new_rate
= req
.rate
;
1299 parent
= req
.best_parent_hw
? req
.best_parent_hw
->core
: NULL
;
1300 } else if (core
->ops
->round_rate
) {
1301 ret
= core
->ops
->round_rate(core
->hw
, rate
,
1307 if (new_rate
< min_rate
|| new_rate
> max_rate
)
1309 } else if (!parent
|| !(core
->flags
& CLK_SET_RATE_PARENT
)) {
1310 /* pass-through clock without adjustable parent */
1311 core
->new_rate
= core
->rate
;
1314 /* pass-through clock with adjustable parent */
1315 top
= clk_calc_new_rates(parent
, rate
);
1316 new_rate
= parent
->new_rate
;
1320 /* some clocks must be gated to change parent */
1321 if (parent
!= old_parent
&&
1322 (core
->flags
& CLK_SET_PARENT_GATE
) && core
->prepare_count
) {
1323 pr_debug("%s: %s not gated but wants to reparent\n",
1324 __func__
, core
->name
);
1328 /* try finding the new parent index */
1329 if (parent
&& core
->num_parents
> 1) {
1330 p_index
= clk_fetch_parent_index(core
, parent
);
1332 pr_debug("%s: clk %s can not be parent of clk %s\n",
1333 __func__
, parent
->name
, core
->name
);
1338 if ((core
->flags
& CLK_SET_RATE_PARENT
) && parent
&&
1339 best_parent_rate
!= parent
->rate
)
1340 top
= clk_calc_new_rates(parent
, best_parent_rate
);
1343 clk_calc_subtree(core
, new_rate
, parent
, p_index
);
1349 * Notify about rate changes in a subtree. Always walk down the whole tree
1350 * so that in case of an error we can walk down the whole tree again and
1353 static struct clk_core
*clk_propagate_rate_change(struct clk_core
*core
,
1354 unsigned long event
)
1356 struct clk_core
*child
, *tmp_clk
, *fail_clk
= NULL
;
1357 int ret
= NOTIFY_DONE
;
1359 if (core
->rate
== core
->new_rate
)
1362 if (core
->notifier_count
) {
1363 ret
= __clk_notify(core
, event
, core
->rate
, core
->new_rate
);
1364 if (ret
& NOTIFY_STOP_MASK
)
1368 hlist_for_each_entry(child
, &core
->children
, child_node
) {
1369 /* Skip children who will be reparented to another clock */
1370 if (child
->new_parent
&& child
->new_parent
!= core
)
1372 tmp_clk
= clk_propagate_rate_change(child
, event
);
1377 /* handle the new child who might not be in core->children yet */
1378 if (core
->new_child
) {
1379 tmp_clk
= clk_propagate_rate_change(core
->new_child
, event
);
1388 * walk down a subtree and set the new rates notifying the rate
1391 static void clk_change_rate(struct clk_core
*core
)
1393 struct clk_core
*child
;
1394 struct hlist_node
*tmp
;
1395 unsigned long old_rate
;
1396 unsigned long best_parent_rate
= 0;
1397 bool skip_set_rate
= false;
1398 struct clk_core
*old_parent
;
1400 old_rate
= core
->rate
;
1402 if (core
->new_parent
)
1403 best_parent_rate
= core
->new_parent
->rate
;
1404 else if (core
->parent
)
1405 best_parent_rate
= core
->parent
->rate
;
1407 if (core
->new_parent
&& core
->new_parent
!= core
->parent
) {
1408 old_parent
= __clk_set_parent_before(core
, core
->new_parent
);
1409 trace_clk_set_parent(core
, core
->new_parent
);
1411 if (core
->ops
->set_rate_and_parent
) {
1412 skip_set_rate
= true;
1413 core
->ops
->set_rate_and_parent(core
->hw
, core
->new_rate
,
1415 core
->new_parent_index
);
1416 } else if (core
->ops
->set_parent
) {
1417 core
->ops
->set_parent(core
->hw
, core
->new_parent_index
);
1420 trace_clk_set_parent_complete(core
, core
->new_parent
);
1421 __clk_set_parent_after(core
, core
->new_parent
, old_parent
);
1424 trace_clk_set_rate(core
, core
->new_rate
);
1426 if (!skip_set_rate
&& core
->ops
->set_rate
)
1427 core
->ops
->set_rate(core
->hw
, core
->new_rate
, best_parent_rate
);
1429 trace_clk_set_rate_complete(core
, core
->new_rate
);
1431 core
->rate
= clk_recalc(core
, best_parent_rate
);
1433 if (core
->notifier_count
&& old_rate
!= core
->rate
)
1434 __clk_notify(core
, POST_RATE_CHANGE
, old_rate
, core
->rate
);
1436 if (core
->flags
& CLK_RECALC_NEW_RATES
)
1437 (void)clk_calc_new_rates(core
, core
->new_rate
);
1440 * Use safe iteration, as change_rate can actually swap parents
1441 * for certain clock types.
1443 hlist_for_each_entry_safe(child
, tmp
, &core
->children
, child_node
) {
1444 /* Skip children who will be reparented to another clock */
1445 if (child
->new_parent
&& child
->new_parent
!= core
)
1447 clk_change_rate(child
);
1450 /* handle the new child who might not be in core->children yet */
1451 if (core
->new_child
)
1452 clk_change_rate(core
->new_child
);
1455 static int clk_core_set_rate_nolock(struct clk_core
*core
,
1456 unsigned long req_rate
)
1458 struct clk_core
*top
, *fail_clk
;
1459 unsigned long rate
= req_rate
;
1465 /* bail early if nothing to do */
1466 if (rate
== clk_core_get_rate_nolock(core
))
1469 if ((core
->flags
& CLK_SET_RATE_GATE
) && core
->prepare_count
)
1472 /* calculate new rates and get the topmost changed clock */
1473 top
= clk_calc_new_rates(core
, rate
);
1477 /* notify that we are about to change rates */
1478 fail_clk
= clk_propagate_rate_change(top
, PRE_RATE_CHANGE
);
1480 pr_debug("%s: failed to set %s rate\n", __func__
,
1482 clk_propagate_rate_change(top
, ABORT_RATE_CHANGE
);
1486 /* change the rates */
1487 clk_change_rate(top
);
1489 core
->req_rate
= req_rate
;
1495 * clk_set_rate - specify a new rate for clk
1496 * @clk: the clk whose rate is being changed
1497 * @rate: the new rate for clk
1499 * In the simplest case clk_set_rate will only adjust the rate of clk.
1501 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1502 * propagate up to clk's parent; whether or not this happens depends on the
1503 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1504 * after calling .round_rate then upstream parent propagation is ignored. If
1505 * *parent_rate comes back with a new rate for clk's parent then we propagate
1506 * up to clk's parent and set its rate. Upward propagation will continue
1507 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1508 * .round_rate stops requesting changes to clk's parent_rate.
1510 * Rate changes are accomplished via tree traversal that also recalculates the
1511 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1513 * Returns 0 on success, -EERROR otherwise.
1515 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
1522 /* prevent racing with updates to the clock topology */
1525 ret
= clk_core_set_rate_nolock(clk
->core
, rate
);
1527 clk_prepare_unlock();
1531 EXPORT_SYMBOL_GPL(clk_set_rate
);
1534 * clk_set_rate_range - set a rate range for a clock source
1535 * @clk: clock source
1536 * @min: desired minimum clock rate in Hz, inclusive
1537 * @max: desired maximum clock rate in Hz, inclusive
1539 * Returns success (0) or negative errno.
1541 int clk_set_rate_range(struct clk
*clk
, unsigned long min
, unsigned long max
)
1549 pr_err("%s: clk %s dev %s con %s: invalid range [%lu, %lu]\n",
1550 __func__
, clk
->core
->name
, clk
->dev_id
, clk
->con_id
,
1557 if (min
!= clk
->min_rate
|| max
!= clk
->max_rate
) {
1558 clk
->min_rate
= min
;
1559 clk
->max_rate
= max
;
1560 ret
= clk_core_set_rate_nolock(clk
->core
, clk
->core
->req_rate
);
1563 clk_prepare_unlock();
1567 EXPORT_SYMBOL_GPL(clk_set_rate_range
);
1570 * clk_set_min_rate - set a minimum clock rate for a clock source
1571 * @clk: clock source
1572 * @rate: desired minimum clock rate in Hz, inclusive
1574 * Returns success (0) or negative errno.
1576 int clk_set_min_rate(struct clk
*clk
, unsigned long rate
)
1581 return clk_set_rate_range(clk
, rate
, clk
->max_rate
);
1583 EXPORT_SYMBOL_GPL(clk_set_min_rate
);
1586 * clk_set_max_rate - set a maximum clock rate for a clock source
1587 * @clk: clock source
1588 * @rate: desired maximum clock rate in Hz, inclusive
1590 * Returns success (0) or negative errno.
1592 int clk_set_max_rate(struct clk
*clk
, unsigned long rate
)
1597 return clk_set_rate_range(clk
, clk
->min_rate
, rate
);
1599 EXPORT_SYMBOL_GPL(clk_set_max_rate
);
1602 * clk_get_parent - return the parent of a clk
1603 * @clk: the clk whose parent gets returned
1605 * Simply returns clk->parent. Returns NULL if clk is NULL.
1607 struct clk
*clk_get_parent(struct clk
*clk
)
1612 parent
= __clk_get_parent(clk
);
1613 clk_prepare_unlock();
1617 EXPORT_SYMBOL_GPL(clk_get_parent
);
1620 * .get_parent is mandatory for clocks with multiple possible parents. It is
1621 * optional for single-parent clocks. Always call .get_parent if it is
1622 * available and WARN if it is missing for multi-parent clocks.
1624 * For single-parent clocks without .get_parent, first check to see if the
1625 * .parents array exists, and if so use it to avoid an expensive tree
1626 * traversal. If .parents does not exist then walk the tree.
1628 static struct clk_core
*__clk_init_parent(struct clk_core
*core
)
1630 struct clk_core
*ret
= NULL
;
1633 /* handle the trivial cases */
1635 if (!core
->num_parents
)
1638 if (core
->num_parents
== 1) {
1639 if (IS_ERR_OR_NULL(core
->parent
))
1640 core
->parent
= clk_core_lookup(core
->parent_names
[0]);
1645 if (!core
->ops
->get_parent
) {
1646 WARN(!core
->ops
->get_parent
,
1647 "%s: multi-parent clocks must implement .get_parent\n",
1653 * Do our best to cache parent clocks in core->parents. This prevents
1654 * unnecessary and expensive lookups. We don't set core->parent here;
1655 * that is done by the calling function.
1658 index
= core
->ops
->get_parent(core
->hw
);
1662 kcalloc(core
->num_parents
, sizeof(struct clk
*),
1665 ret
= clk_core_get_parent_by_index(core
, index
);
1671 static void clk_core_reparent(struct clk_core
*core
,
1672 struct clk_core
*new_parent
)
1674 clk_reparent(core
, new_parent
);
1675 __clk_recalc_accuracies(core
);
1676 __clk_recalc_rates(core
, POST_RATE_CHANGE
);
1679 void clk_hw_reparent(struct clk_hw
*hw
, struct clk_hw
*new_parent
)
1684 clk_core_reparent(hw
->core
, !new_parent
? NULL
: new_parent
->core
);
1688 * clk_has_parent - check if a clock is a possible parent for another
1689 * @clk: clock source
1690 * @parent: parent clock source
1692 * This function can be used in drivers that need to check that a clock can be
1693 * the parent of another without actually changing the parent.
1695 * Returns true if @parent is a possible parent for @clk, false otherwise.
1697 bool clk_has_parent(struct clk
*clk
, struct clk
*parent
)
1699 struct clk_core
*core
, *parent_core
;
1702 /* NULL clocks should be nops, so return success if either is NULL. */
1703 if (!clk
|| !parent
)
1707 parent_core
= parent
->core
;
1709 /* Optimize for the case where the parent is already the parent. */
1710 if (core
->parent
== parent_core
)
1713 for (i
= 0; i
< core
->num_parents
; i
++)
1714 if (strcmp(core
->parent_names
[i
], parent_core
->name
) == 0)
1719 EXPORT_SYMBOL_GPL(clk_has_parent
);
1721 static int clk_core_set_parent(struct clk_core
*core
, struct clk_core
*parent
)
1725 unsigned long p_rate
= 0;
1730 /* prevent racing with updates to the clock topology */
1733 if (core
->parent
== parent
)
1736 /* verify ops for for multi-parent clks */
1737 if ((core
->num_parents
> 1) && (!core
->ops
->set_parent
)) {
1742 /* check that we are allowed to re-parent if the clock is in use */
1743 if ((core
->flags
& CLK_SET_PARENT_GATE
) && core
->prepare_count
) {
1748 /* try finding the new parent index */
1750 p_index
= clk_fetch_parent_index(core
, parent
);
1751 p_rate
= parent
->rate
;
1753 pr_debug("%s: clk %s can not be parent of clk %s\n",
1754 __func__
, parent
->name
, core
->name
);
1760 /* propagate PRE_RATE_CHANGE notifications */
1761 ret
= __clk_speculate_rates(core
, p_rate
);
1763 /* abort if a driver objects */
1764 if (ret
& NOTIFY_STOP_MASK
)
1767 /* do the re-parent */
1768 ret
= __clk_set_parent(core
, parent
, p_index
);
1770 /* propagate rate an accuracy recalculation accordingly */
1772 __clk_recalc_rates(core
, ABORT_RATE_CHANGE
);
1774 __clk_recalc_rates(core
, POST_RATE_CHANGE
);
1775 __clk_recalc_accuracies(core
);
1779 clk_prepare_unlock();
1785 * clk_set_parent - switch the parent of a mux clk
1786 * @clk: the mux clk whose input we are switching
1787 * @parent: the new input to clk
1789 * Re-parent clk to use parent as its new input source. If clk is in
1790 * prepared state, the clk will get enabled for the duration of this call. If
1791 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1792 * that, the reparenting is glitchy in hardware, etc), use the
1793 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1795 * After successfully changing clk's parent clk_set_parent will update the
1796 * clk topology, sysfs topology and propagate rate recalculation via
1797 * __clk_recalc_rates.
1799 * Returns 0 on success, -EERROR otherwise.
1801 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
1806 return clk_core_set_parent(clk
->core
, parent
? parent
->core
: NULL
);
1808 EXPORT_SYMBOL_GPL(clk_set_parent
);
1811 * clk_set_phase - adjust the phase shift of a clock signal
1812 * @clk: clock signal source
1813 * @degrees: number of degrees the signal is shifted
1815 * Shifts the phase of a clock signal by the specified
1816 * degrees. Returns 0 on success, -EERROR otherwise.
1818 * This function makes no distinction about the input or reference
1819 * signal that we adjust the clock signal phase against. For example
1820 * phase locked-loop clock signal generators we may shift phase with
1821 * respect to feedback clock signal input, but for other cases the
1822 * clock phase may be shifted with respect to some other, unspecified
1825 * Additionally the concept of phase shift does not propagate through
1826 * the clock tree hierarchy, which sets it apart from clock rates and
1827 * clock accuracy. A parent clock phase attribute does not have an
1828 * impact on the phase attribute of a child clock.
1830 int clk_set_phase(struct clk
*clk
, int degrees
)
1837 /* sanity check degrees */
1844 trace_clk_set_phase(clk
->core
, degrees
);
1846 if (clk
->core
->ops
->set_phase
)
1847 ret
= clk
->core
->ops
->set_phase(clk
->core
->hw
, degrees
);
1849 trace_clk_set_phase_complete(clk
->core
, degrees
);
1852 clk
->core
->phase
= degrees
;
1854 clk_prepare_unlock();
1858 EXPORT_SYMBOL_GPL(clk_set_phase
);
1860 static int clk_core_get_phase(struct clk_core
*core
)
1866 clk_prepare_unlock();
1872 * clk_get_phase - return the phase shift of a clock signal
1873 * @clk: clock signal source
1875 * Returns the phase shift of a clock node in degrees, otherwise returns
1878 int clk_get_phase(struct clk
*clk
)
1883 return clk_core_get_phase(clk
->core
);
1885 EXPORT_SYMBOL_GPL(clk_get_phase
);
1888 * clk_is_match - check if two clk's point to the same hardware clock
1889 * @p: clk compared against q
1890 * @q: clk compared against p
1892 * Returns true if the two struct clk pointers both point to the same hardware
1893 * clock node. Put differently, returns true if struct clk *p and struct clk *q
1894 * share the same struct clk_core object.
1896 * Returns false otherwise. Note that two NULL clks are treated as matching.
1898 bool clk_is_match(const struct clk
*p
, const struct clk
*q
)
1900 /* trivial case: identical struct clk's or both NULL */
1904 /* true if clk->core pointers match. Avoid derefing garbage */
1905 if (!IS_ERR_OR_NULL(p
) && !IS_ERR_OR_NULL(q
))
1906 if (p
->core
== q
->core
)
1911 EXPORT_SYMBOL_GPL(clk_is_match
);
1913 /*** debugfs support ***/
1915 #ifdef CONFIG_DEBUG_FS
1916 #include <linux/debugfs.h>
1918 static struct dentry
*rootdir
;
1919 static int inited
= 0;
1920 static DEFINE_MUTEX(clk_debug_lock
);
1921 static HLIST_HEAD(clk_debug_list
);
1923 static struct hlist_head
*all_lists
[] = {
1929 static struct hlist_head
*orphan_list
[] = {
1934 static void clk_summary_show_one(struct seq_file
*s
, struct clk_core
*c
,
1940 seq_printf(s
, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
1942 30 - level
* 3, c
->name
,
1943 c
->enable_count
, c
->prepare_count
, clk_core_get_rate(c
),
1944 clk_core_get_accuracy(c
), clk_core_get_phase(c
));
1947 static void clk_summary_show_subtree(struct seq_file
*s
, struct clk_core
*c
,
1950 struct clk_core
*child
;
1955 clk_summary_show_one(s
, c
, level
);
1957 hlist_for_each_entry(child
, &c
->children
, child_node
)
1958 clk_summary_show_subtree(s
, child
, level
+ 1);
1961 static int clk_summary_show(struct seq_file
*s
, void *data
)
1964 struct hlist_head
**lists
= (struct hlist_head
**)s
->private;
1966 seq_puts(s
, " clock enable_cnt prepare_cnt rate accuracy phase\n");
1967 seq_puts(s
, "----------------------------------------------------------------------------------------\n");
1971 for (; *lists
; lists
++)
1972 hlist_for_each_entry(c
, *lists
, child_node
)
1973 clk_summary_show_subtree(s
, c
, 0);
1975 clk_prepare_unlock();
1981 static int clk_summary_open(struct inode
*inode
, struct file
*file
)
1983 return single_open(file
, clk_summary_show
, inode
->i_private
);
1986 static const struct file_operations clk_summary_fops
= {
1987 .open
= clk_summary_open
,
1989 .llseek
= seq_lseek
,
1990 .release
= single_release
,
1993 static void clk_dump_one(struct seq_file
*s
, struct clk_core
*c
, int level
)
1998 /* This should be JSON format, i.e. elements separated with a comma */
1999 seq_printf(s
, "\"%s\": { ", c
->name
);
2000 seq_printf(s
, "\"enable_count\": %d,", c
->enable_count
);
2001 seq_printf(s
, "\"prepare_count\": %d,", c
->prepare_count
);
2002 seq_printf(s
, "\"rate\": %lu,", clk_core_get_rate(c
));
2003 seq_printf(s
, "\"accuracy\": %lu,", clk_core_get_accuracy(c
));
2004 seq_printf(s
, "\"phase\": %d", clk_core_get_phase(c
));
2007 static void clk_dump_subtree(struct seq_file
*s
, struct clk_core
*c
, int level
)
2009 struct clk_core
*child
;
2014 clk_dump_one(s
, c
, level
);
2016 hlist_for_each_entry(child
, &c
->children
, child_node
) {
2018 clk_dump_subtree(s
, child
, level
+ 1);
2024 static int clk_dump(struct seq_file
*s
, void *data
)
2027 bool first_node
= true;
2028 struct hlist_head
**lists
= (struct hlist_head
**)s
->private;
2034 for (; *lists
; lists
++) {
2035 hlist_for_each_entry(c
, *lists
, child_node
) {
2039 clk_dump_subtree(s
, c
, 0);
2043 clk_prepare_unlock();
2050 static int clk_dump_open(struct inode
*inode
, struct file
*file
)
2052 return single_open(file
, clk_dump
, inode
->i_private
);
2055 static const struct file_operations clk_dump_fops
= {
2056 .open
= clk_dump_open
,
2058 .llseek
= seq_lseek
,
2059 .release
= single_release
,
2062 static int clk_debug_create_one(struct clk_core
*core
, struct dentry
*pdentry
)
2067 if (!core
|| !pdentry
) {
2072 d
= debugfs_create_dir(core
->name
, pdentry
);
2078 d
= debugfs_create_u32("clk_rate", S_IRUGO
, core
->dentry
,
2079 (u32
*)&core
->rate
);
2083 d
= debugfs_create_u32("clk_accuracy", S_IRUGO
, core
->dentry
,
2084 (u32
*)&core
->accuracy
);
2088 d
= debugfs_create_u32("clk_phase", S_IRUGO
, core
->dentry
,
2089 (u32
*)&core
->phase
);
2093 d
= debugfs_create_x32("clk_flags", S_IRUGO
, core
->dentry
,
2094 (u32
*)&core
->flags
);
2098 d
= debugfs_create_u32("clk_prepare_count", S_IRUGO
, core
->dentry
,
2099 (u32
*)&core
->prepare_count
);
2103 d
= debugfs_create_u32("clk_enable_count", S_IRUGO
, core
->dentry
,
2104 (u32
*)&core
->enable_count
);
2108 d
= debugfs_create_u32("clk_notifier_count", S_IRUGO
, core
->dentry
,
2109 (u32
*)&core
->notifier_count
);
2113 if (core
->ops
->debug_init
) {
2114 ret
= core
->ops
->debug_init(core
->hw
, core
->dentry
);
2123 debugfs_remove_recursive(core
->dentry
);
2124 core
->dentry
= NULL
;
2130 * clk_debug_register - add a clk node to the debugfs clk directory
2131 * @core: the clk being added to the debugfs clk directory
2133 * Dynamically adds a clk to the debugfs clk directory if debugfs has been
2134 * initialized. Otherwise it bails out early since the debugfs clk directory
2135 * will be created lazily by clk_debug_init as part of a late_initcall.
2137 static int clk_debug_register(struct clk_core
*core
)
2141 mutex_lock(&clk_debug_lock
);
2142 hlist_add_head(&core
->debug_node
, &clk_debug_list
);
2147 ret
= clk_debug_create_one(core
, rootdir
);
2149 mutex_unlock(&clk_debug_lock
);
2155 * clk_debug_unregister - remove a clk node from the debugfs clk directory
2156 * @core: the clk being removed from the debugfs clk directory
2158 * Dynamically removes a clk and all its child nodes from the
2159 * debugfs clk directory if clk->dentry points to debugfs created by
2160 * clk_debug_register in __clk_init.
2162 static void clk_debug_unregister(struct clk_core
*core
)
2164 mutex_lock(&clk_debug_lock
);
2165 hlist_del_init(&core
->debug_node
);
2166 debugfs_remove_recursive(core
->dentry
);
2167 core
->dentry
= NULL
;
2168 mutex_unlock(&clk_debug_lock
);
2171 struct dentry
*clk_debugfs_add_file(struct clk_hw
*hw
, char *name
, umode_t mode
,
2172 void *data
, const struct file_operations
*fops
)
2174 struct dentry
*d
= NULL
;
2176 if (hw
->core
->dentry
)
2177 d
= debugfs_create_file(name
, mode
, hw
->core
->dentry
, data
,
2182 EXPORT_SYMBOL_GPL(clk_debugfs_add_file
);
2185 * clk_debug_init - lazily populate the debugfs clk directory
2187 * clks are often initialized very early during boot before memory can be
2188 * dynamically allocated and well before debugfs is setup. This function
2189 * populates the debugfs clk directory once at boot-time when we know that
2190 * debugfs is setup. It should only be called once at boot-time, all other clks
2191 * added dynamically will be done so with clk_debug_register.
2193 static int __init
clk_debug_init(void)
2195 struct clk_core
*core
;
2198 rootdir
= debugfs_create_dir("clk", NULL
);
2203 d
= debugfs_create_file("clk_summary", S_IRUGO
, rootdir
, &all_lists
,
2208 d
= debugfs_create_file("clk_dump", S_IRUGO
, rootdir
, &all_lists
,
2213 d
= debugfs_create_file("clk_orphan_summary", S_IRUGO
, rootdir
,
2214 &orphan_list
, &clk_summary_fops
);
2218 d
= debugfs_create_file("clk_orphan_dump", S_IRUGO
, rootdir
,
2219 &orphan_list
, &clk_dump_fops
);
2223 mutex_lock(&clk_debug_lock
);
2224 hlist_for_each_entry(core
, &clk_debug_list
, debug_node
)
2225 clk_debug_create_one(core
, rootdir
);
2228 mutex_unlock(&clk_debug_lock
);
2232 late_initcall(clk_debug_init
);
2234 static inline int clk_debug_register(struct clk_core
*core
) { return 0; }
2235 static inline void clk_debug_reparent(struct clk_core
*core
,
2236 struct clk_core
*new_parent
)
2239 static inline void clk_debug_unregister(struct clk_core
*core
)
2245 * __clk_init - initialize the data structures in a struct clk
2246 * @dev: device initializing this clk, placeholder for now
2247 * @clk: clk being initialized
2249 * Initializes the lists in struct clk_core, queries the hardware for the
2250 * parent and rate and sets them both.
2252 static int __clk_init(struct device
*dev
, struct clk
*clk_user
)
2255 struct clk_core
*orphan
;
2256 struct hlist_node
*tmp2
;
2257 struct clk_core
*core
;
2263 core
= clk_user
->core
;
2267 /* check to see if a clock with this name is already registered */
2268 if (clk_core_lookup(core
->name
)) {
2269 pr_debug("%s: clk %s already initialized\n",
2270 __func__
, core
->name
);
2275 /* check that clk_ops are sane. See Documentation/clk.txt */
2276 if (core
->ops
->set_rate
&&
2277 !((core
->ops
->round_rate
|| core
->ops
->determine_rate
) &&
2278 core
->ops
->recalc_rate
)) {
2279 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
2280 __func__
, core
->name
);
2285 if (core
->ops
->set_parent
&& !core
->ops
->get_parent
) {
2286 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
2287 __func__
, core
->name
);
2292 if (core
->ops
->set_rate_and_parent
&&
2293 !(core
->ops
->set_parent
&& core
->ops
->set_rate
)) {
2294 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
2295 __func__
, core
->name
);
2300 /* throw a WARN if any entries in parent_names are NULL */
2301 for (i
= 0; i
< core
->num_parents
; i
++)
2302 WARN(!core
->parent_names
[i
],
2303 "%s: invalid NULL in %s's .parent_names\n",
2304 __func__
, core
->name
);
2307 * Allocate an array of struct clk *'s to avoid unnecessary string
2308 * look-ups of clk's possible parents. This can fail for clocks passed
2309 * in to clk_init during early boot; thus any access to core->parents[]
2310 * must always check for a NULL pointer and try to populate it if
2313 * If core->parents is not NULL we skip this entire block. This allows
2314 * for clock drivers to statically initialize core->parents.
2316 if (core
->num_parents
> 1 && !core
->parents
) {
2317 core
->parents
= kcalloc(core
->num_parents
, sizeof(struct clk
*),
2320 * clk_core_lookup returns NULL for parents that have not been
2321 * clk_init'd; thus any access to clk->parents[] must check
2322 * for a NULL pointer. We can always perform lazy lookups for
2323 * missing parents later on.
2326 for (i
= 0; i
< core
->num_parents
; i
++)
2328 clk_core_lookup(core
->parent_names
[i
]);
2331 core
->parent
= __clk_init_parent(core
);
2334 * Populate core->parent if parent has already been __clk_init'd. If
2335 * parent has not yet been __clk_init'd then place clk in the orphan
2336 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
2339 * Every time a new clk is clk_init'd then we walk the list of orphan
2340 * clocks and re-parent any that are children of the clock currently
2344 hlist_add_head(&core
->child_node
,
2345 &core
->parent
->children
);
2346 else if (core
->flags
& CLK_IS_ROOT
)
2347 hlist_add_head(&core
->child_node
, &clk_root_list
);
2349 hlist_add_head(&core
->child_node
, &clk_orphan_list
);
2352 * Set clk's accuracy. The preferred method is to use
2353 * .recalc_accuracy. For simple clocks and lazy developers the default
2354 * fallback is to use the parent's accuracy. If a clock doesn't have a
2355 * parent (or is orphaned) then accuracy is set to zero (perfect
2358 if (core
->ops
->recalc_accuracy
)
2359 core
->accuracy
= core
->ops
->recalc_accuracy(core
->hw
,
2360 __clk_get_accuracy(core
->parent
));
2361 else if (core
->parent
)
2362 core
->accuracy
= core
->parent
->accuracy
;
2368 * Since a phase is by definition relative to its parent, just
2369 * query the current clock phase, or just assume it's in phase.
2371 if (core
->ops
->get_phase
)
2372 core
->phase
= core
->ops
->get_phase(core
->hw
);
2377 * Set clk's rate. The preferred method is to use .recalc_rate. For
2378 * simple clocks and lazy developers the default fallback is to use the
2379 * parent's rate. If a clock doesn't have a parent (or is orphaned)
2380 * then rate is set to zero.
2382 if (core
->ops
->recalc_rate
)
2383 rate
= core
->ops
->recalc_rate(core
->hw
,
2384 clk_core_get_rate_nolock(core
->parent
));
2385 else if (core
->parent
)
2386 rate
= core
->parent
->rate
;
2389 core
->rate
= core
->req_rate
= rate
;
2392 * walk the list of orphan clocks and reparent any that are children of
2395 hlist_for_each_entry_safe(orphan
, tmp2
, &clk_orphan_list
, child_node
) {
2396 if (orphan
->num_parents
&& orphan
->ops
->get_parent
) {
2397 i
= orphan
->ops
->get_parent(orphan
->hw
);
2398 if (!strcmp(core
->name
, orphan
->parent_names
[i
]))
2399 clk_core_reparent(orphan
, core
);
2403 for (i
= 0; i
< orphan
->num_parents
; i
++)
2404 if (!strcmp(core
->name
, orphan
->parent_names
[i
])) {
2405 clk_core_reparent(orphan
, core
);
2411 * optional platform-specific magic
2413 * The .init callback is not used by any of the basic clock types, but
2414 * exists for weird hardware that must perform initialization magic.
2415 * Please consider other ways of solving initialization problems before
2416 * using this callback, as its use is discouraged.
2418 if (core
->ops
->init
)
2419 core
->ops
->init(core
->hw
);
2421 kref_init(&core
->ref
);
2423 clk_prepare_unlock();
2426 clk_debug_register(core
);
2431 struct clk
*__clk_create_clk(struct clk_hw
*hw
, const char *dev_id
,
2436 /* This is to allow this function to be chained to others */
2437 if (!hw
|| IS_ERR(hw
))
2438 return (struct clk
*) hw
;
2440 clk
= kzalloc(sizeof(*clk
), GFP_KERNEL
);
2442 return ERR_PTR(-ENOMEM
);
2444 clk
->core
= hw
->core
;
2445 clk
->dev_id
= dev_id
;
2446 clk
->con_id
= con_id
;
2447 clk
->max_rate
= ULONG_MAX
;
2450 hlist_add_head(&clk
->clks_node
, &hw
->core
->clks
);
2451 clk_prepare_unlock();
2456 void __clk_free_clk(struct clk
*clk
)
2459 hlist_del(&clk
->clks_node
);
2460 clk_prepare_unlock();
2466 * clk_register - allocate a new clock, register it and return an opaque cookie
2467 * @dev: device that is registering this clock
2468 * @hw: link to hardware-specific clock data
2470 * clk_register is the primary interface for populating the clock tree with new
2471 * clock nodes. It returns a pointer to the newly allocated struct clk which
2472 * cannot be dereferenced by driver code but may be used in conjunction with the
2473 * rest of the clock API. In the event of an error clk_register will return an
2474 * error code; drivers must test for an error code after calling clk_register.
2476 struct clk
*clk_register(struct device
*dev
, struct clk_hw
*hw
)
2479 struct clk_core
*core
;
2481 core
= kzalloc(sizeof(*core
), GFP_KERNEL
);
2487 core
->name
= kstrdup_const(hw
->init
->name
, GFP_KERNEL
);
2492 core
->ops
= hw
->init
->ops
;
2493 if (dev
&& dev
->driver
)
2494 core
->owner
= dev
->driver
->owner
;
2496 core
->flags
= hw
->init
->flags
;
2497 core
->num_parents
= hw
->init
->num_parents
;
2500 /* allocate local copy in case parent_names is __initdata */
2501 core
->parent_names
= kcalloc(core
->num_parents
, sizeof(char *),
2504 if (!core
->parent_names
) {
2506 goto fail_parent_names
;
2510 /* copy each string name in case parent_names is __initdata */
2511 for (i
= 0; i
< core
->num_parents
; i
++) {
2512 core
->parent_names
[i
] = kstrdup_const(hw
->init
->parent_names
[i
],
2514 if (!core
->parent_names
[i
]) {
2516 goto fail_parent_names_copy
;
2520 INIT_HLIST_HEAD(&core
->clks
);
2522 hw
->clk
= __clk_create_clk(hw
, NULL
, NULL
);
2523 if (IS_ERR(hw
->clk
)) {
2524 ret
= PTR_ERR(hw
->clk
);
2525 goto fail_parent_names_copy
;
2528 ret
= __clk_init(dev
, hw
->clk
);
2532 __clk_free_clk(hw
->clk
);
2535 fail_parent_names_copy
:
2537 kfree_const(core
->parent_names
[i
]);
2538 kfree(core
->parent_names
);
2540 kfree_const(core
->name
);
2544 return ERR_PTR(ret
);
2546 EXPORT_SYMBOL_GPL(clk_register
);
2548 /* Free memory allocated for a clock. */
2549 static void __clk_release(struct kref
*ref
)
2551 struct clk_core
*core
= container_of(ref
, struct clk_core
, ref
);
2552 int i
= core
->num_parents
;
2554 lockdep_assert_held(&prepare_lock
);
2556 kfree(core
->parents
);
2558 kfree_const(core
->parent_names
[i
]);
2560 kfree(core
->parent_names
);
2561 kfree_const(core
->name
);
2566 * Empty clk_ops for unregistered clocks. These are used temporarily
2567 * after clk_unregister() was called on a clock and until last clock
2568 * consumer calls clk_put() and the struct clk object is freed.
2570 static int clk_nodrv_prepare_enable(struct clk_hw
*hw
)
2575 static void clk_nodrv_disable_unprepare(struct clk_hw
*hw
)
2580 static int clk_nodrv_set_rate(struct clk_hw
*hw
, unsigned long rate
,
2581 unsigned long parent_rate
)
2586 static int clk_nodrv_set_parent(struct clk_hw
*hw
, u8 index
)
2591 static const struct clk_ops clk_nodrv_ops
= {
2592 .enable
= clk_nodrv_prepare_enable
,
2593 .disable
= clk_nodrv_disable_unprepare
,
2594 .prepare
= clk_nodrv_prepare_enable
,
2595 .unprepare
= clk_nodrv_disable_unprepare
,
2596 .set_rate
= clk_nodrv_set_rate
,
2597 .set_parent
= clk_nodrv_set_parent
,
2601 * clk_unregister - unregister a currently registered clock
2602 * @clk: clock to unregister
2604 void clk_unregister(struct clk
*clk
)
2606 unsigned long flags
;
2608 if (!clk
|| WARN_ON_ONCE(IS_ERR(clk
)))
2611 clk_debug_unregister(clk
->core
);
2615 if (clk
->core
->ops
== &clk_nodrv_ops
) {
2616 pr_err("%s: unregistered clock: %s\n", __func__
,
2621 * Assign empty clock ops for consumers that might still hold
2622 * a reference to this clock.
2624 flags
= clk_enable_lock();
2625 clk
->core
->ops
= &clk_nodrv_ops
;
2626 clk_enable_unlock(flags
);
2628 if (!hlist_empty(&clk
->core
->children
)) {
2629 struct clk_core
*child
;
2630 struct hlist_node
*t
;
2632 /* Reparent all children to the orphan list. */
2633 hlist_for_each_entry_safe(child
, t
, &clk
->core
->children
,
2635 clk_core_set_parent(child
, NULL
);
2638 hlist_del_init(&clk
->core
->child_node
);
2640 if (clk
->core
->prepare_count
)
2641 pr_warn("%s: unregistering prepared clock: %s\n",
2642 __func__
, clk
->core
->name
);
2643 kref_put(&clk
->core
->ref
, __clk_release
);
2645 clk_prepare_unlock();
2647 EXPORT_SYMBOL_GPL(clk_unregister
);
2649 static void devm_clk_release(struct device
*dev
, void *res
)
2651 clk_unregister(*(struct clk
**)res
);
2655 * devm_clk_register - resource managed clk_register()
2656 * @dev: device that is registering this clock
2657 * @hw: link to hardware-specific clock data
2659 * Managed clk_register(). Clocks returned from this function are
2660 * automatically clk_unregister()ed on driver detach. See clk_register() for
2663 struct clk
*devm_clk_register(struct device
*dev
, struct clk_hw
*hw
)
2668 clkp
= devres_alloc(devm_clk_release
, sizeof(*clkp
), GFP_KERNEL
);
2670 return ERR_PTR(-ENOMEM
);
2672 clk
= clk_register(dev
, hw
);
2675 devres_add(dev
, clkp
);
2682 EXPORT_SYMBOL_GPL(devm_clk_register
);
2684 static int devm_clk_match(struct device
*dev
, void *res
, void *data
)
2686 struct clk
*c
= res
;
2693 * devm_clk_unregister - resource managed clk_unregister()
2694 * @clk: clock to unregister
2696 * Deallocate a clock allocated with devm_clk_register(). Normally
2697 * this function will not need to be called and the resource management
2698 * code will ensure that the resource is freed.
2700 void devm_clk_unregister(struct device
*dev
, struct clk
*clk
)
2702 WARN_ON(devres_release(dev
, devm_clk_release
, devm_clk_match
, clk
));
2704 EXPORT_SYMBOL_GPL(devm_clk_unregister
);
2709 int __clk_get(struct clk
*clk
)
2711 struct clk_core
*core
= !clk
? NULL
: clk
->core
;
2714 if (!try_module_get(core
->owner
))
2717 kref_get(&core
->ref
);
2722 void __clk_put(struct clk
*clk
)
2724 struct module
*owner
;
2726 if (!clk
|| WARN_ON_ONCE(IS_ERR(clk
)))
2731 hlist_del(&clk
->clks_node
);
2732 if (clk
->min_rate
> clk
->core
->req_rate
||
2733 clk
->max_rate
< clk
->core
->req_rate
)
2734 clk_core_set_rate_nolock(clk
->core
, clk
->core
->req_rate
);
2736 owner
= clk
->core
->owner
;
2737 kref_put(&clk
->core
->ref
, __clk_release
);
2739 clk_prepare_unlock();
2746 /*** clk rate change notifiers ***/
2749 * clk_notifier_register - add a clk rate change notifier
2750 * @clk: struct clk * to watch
2751 * @nb: struct notifier_block * with callback info
2753 * Request notification when clk's rate changes. This uses an SRCU
2754 * notifier because we want it to block and notifier unregistrations are
2755 * uncommon. The callbacks associated with the notifier must not
2756 * re-enter into the clk framework by calling any top-level clk APIs;
2757 * this will cause a nested prepare_lock mutex.
2759 * In all notification cases cases (pre, post and abort rate change) the
2760 * original clock rate is passed to the callback via struct
2761 * clk_notifier_data.old_rate and the new frequency is passed via struct
2762 * clk_notifier_data.new_rate.
2764 * clk_notifier_register() must be called from non-atomic context.
2765 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2766 * allocation failure; otherwise, passes along the return value of
2767 * srcu_notifier_chain_register().
2769 int clk_notifier_register(struct clk
*clk
, struct notifier_block
*nb
)
2771 struct clk_notifier
*cn
;
2779 /* search the list of notifiers for this clk */
2780 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2784 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2785 if (cn
->clk
!= clk
) {
2786 cn
= kzalloc(sizeof(struct clk_notifier
), GFP_KERNEL
);
2791 srcu_init_notifier_head(&cn
->notifier_head
);
2793 list_add(&cn
->node
, &clk_notifier_list
);
2796 ret
= srcu_notifier_chain_register(&cn
->notifier_head
, nb
);
2798 clk
->core
->notifier_count
++;
2801 clk_prepare_unlock();
2805 EXPORT_SYMBOL_GPL(clk_notifier_register
);
2808 * clk_notifier_unregister - remove a clk rate change notifier
2809 * @clk: struct clk *
2810 * @nb: struct notifier_block * with callback info
2812 * Request no further notification for changes to 'clk' and frees memory
2813 * allocated in clk_notifier_register.
2815 * Returns -EINVAL if called with null arguments; otherwise, passes
2816 * along the return value of srcu_notifier_chain_unregister().
2818 int clk_notifier_unregister(struct clk
*clk
, struct notifier_block
*nb
)
2820 struct clk_notifier
*cn
= NULL
;
2828 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2832 if (cn
->clk
== clk
) {
2833 ret
= srcu_notifier_chain_unregister(&cn
->notifier_head
, nb
);
2835 clk
->core
->notifier_count
--;
2837 /* XXX the notifier code should handle this better */
2838 if (!cn
->notifier_head
.head
) {
2839 srcu_cleanup_notifier_head(&cn
->notifier_head
);
2840 list_del(&cn
->node
);
2848 clk_prepare_unlock();
2852 EXPORT_SYMBOL_GPL(clk_notifier_unregister
);
2856 * struct of_clk_provider - Clock provider registration structure
2857 * @link: Entry in global list of clock providers
2858 * @node: Pointer to device tree node of clock provider
2859 * @get: Get clock callback. Returns NULL or a struct clk for the
2860 * given clock specifier
2861 * @data: context pointer to be passed into @get callback
2863 struct of_clk_provider
{
2864 struct list_head link
;
2866 struct device_node
*node
;
2867 struct clk
*(*get
)(struct of_phandle_args
*clkspec
, void *data
);
2871 static const struct of_device_id __clk_of_table_sentinel
2872 __used
__section(__clk_of_table_end
);
2874 static LIST_HEAD(of_clk_providers
);
2875 static DEFINE_MUTEX(of_clk_mutex
);
2877 struct clk
*of_clk_src_simple_get(struct of_phandle_args
*clkspec
,
2882 EXPORT_SYMBOL_GPL(of_clk_src_simple_get
);
2884 struct clk
*of_clk_src_onecell_get(struct of_phandle_args
*clkspec
, void *data
)
2886 struct clk_onecell_data
*clk_data
= data
;
2887 unsigned int idx
= clkspec
->args
[0];
2889 if (idx
>= clk_data
->clk_num
) {
2890 pr_err("%s: invalid clock index %d\n", __func__
, idx
);
2891 return ERR_PTR(-EINVAL
);
2894 return clk_data
->clks
[idx
];
2896 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get
);
2899 * of_clk_add_provider() - Register a clock provider for a node
2900 * @np: Device node pointer associated with clock provider
2901 * @clk_src_get: callback for decoding clock
2902 * @data: context pointer for @clk_src_get callback.
2904 int of_clk_add_provider(struct device_node
*np
,
2905 struct clk
*(*clk_src_get
)(struct of_phandle_args
*clkspec
,
2909 struct of_clk_provider
*cp
;
2912 cp
= kzalloc(sizeof(struct of_clk_provider
), GFP_KERNEL
);
2916 cp
->node
= of_node_get(np
);
2918 cp
->get
= clk_src_get
;
2920 mutex_lock(&of_clk_mutex
);
2921 list_add(&cp
->link
, &of_clk_providers
);
2922 mutex_unlock(&of_clk_mutex
);
2923 pr_debug("Added clock from %s\n", np
->full_name
);
2925 ret
= of_clk_set_defaults(np
, true);
2927 of_clk_del_provider(np
);
2931 EXPORT_SYMBOL_GPL(of_clk_add_provider
);
2934 * of_clk_del_provider() - Remove a previously registered clock provider
2935 * @np: Device node pointer associated with clock provider
2937 void of_clk_del_provider(struct device_node
*np
)
2939 struct of_clk_provider
*cp
;
2941 mutex_lock(&of_clk_mutex
);
2942 list_for_each_entry(cp
, &of_clk_providers
, link
) {
2943 if (cp
->node
== np
) {
2944 list_del(&cp
->link
);
2945 of_node_put(cp
->node
);
2950 mutex_unlock(&of_clk_mutex
);
2952 EXPORT_SYMBOL_GPL(of_clk_del_provider
);
2954 struct clk
*__of_clk_get_from_provider(struct of_phandle_args
*clkspec
,
2955 const char *dev_id
, const char *con_id
)
2957 struct of_clk_provider
*provider
;
2958 struct clk
*clk
= ERR_PTR(-EPROBE_DEFER
);
2961 return ERR_PTR(-EINVAL
);
2963 /* Check if we have such a provider in our array */
2964 mutex_lock(&of_clk_mutex
);
2965 list_for_each_entry(provider
, &of_clk_providers
, link
) {
2966 if (provider
->node
== clkspec
->np
)
2967 clk
= provider
->get(clkspec
, provider
->data
);
2969 clk
= __clk_create_clk(__clk_get_hw(clk
), dev_id
,
2972 if (!IS_ERR(clk
) && !__clk_get(clk
)) {
2973 __clk_free_clk(clk
);
2974 clk
= ERR_PTR(-ENOENT
);
2980 mutex_unlock(&of_clk_mutex
);
2986 * of_clk_get_from_provider() - Lookup a clock from a clock provider
2987 * @clkspec: pointer to a clock specifier data structure
2989 * This function looks up a struct clk from the registered list of clock
2990 * providers, an input is a clock specifier data structure as returned
2991 * from the of_parse_phandle_with_args() function call.
2993 struct clk
*of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2995 return __of_clk_get_from_provider(clkspec
, NULL
, __func__
);
2998 int of_clk_get_parent_count(struct device_node
*np
)
3000 return of_count_phandle_with_args(np
, "clocks", "#clock-cells");
3002 EXPORT_SYMBOL_GPL(of_clk_get_parent_count
);
3004 const char *of_clk_get_parent_name(struct device_node
*np
, int index
)
3006 struct of_phandle_args clkspec
;
3007 struct property
*prop
;
3008 const char *clk_name
;
3017 rc
= of_parse_phandle_with_args(np
, "clocks", "#clock-cells", index
,
3022 index
= clkspec
.args_count
? clkspec
.args
[0] : 0;
3025 /* if there is an indices property, use it to transfer the index
3026 * specified into an array offset for the clock-output-names property.
3028 of_property_for_each_u32(clkspec
.np
, "clock-indices", prop
, vp
, pv
) {
3036 if (of_property_read_string_index(clkspec
.np
, "clock-output-names",
3039 clk_name
= clkspec
.np
->name
;
3041 of_node_put(clkspec
.np
);
3044 EXPORT_SYMBOL_GPL(of_clk_get_parent_name
);
3047 * of_clk_parent_fill() - Fill @parents with names of @np's parents and return
3049 * @np: Device node pointer associated with clock provider
3050 * @parents: pointer to char array that hold the parents' names
3051 * @size: size of the @parents array
3053 * Return: number of parents for the clock node.
3055 int of_clk_parent_fill(struct device_node
*np
, const char **parents
,
3060 while (i
< size
&& (parents
[i
] = of_clk_get_parent_name(np
, i
)) != NULL
)
3065 EXPORT_SYMBOL_GPL(of_clk_parent_fill
);
3067 struct clock_provider
{
3068 of_clk_init_cb_t clk_init_cb
;
3069 struct device_node
*np
;
3070 struct list_head node
;
3073 static LIST_HEAD(clk_provider_list
);
3076 * This function looks for a parent clock. If there is one, then it
3077 * checks that the provider for this parent clock was initialized, in
3078 * this case the parent clock will be ready.
3080 static int parent_ready(struct device_node
*np
)
3085 struct clk
*clk
= of_clk_get(np
, i
);
3087 /* this parent is ready we can check the next one */
3094 /* at least one parent is not ready, we exit now */
3095 if (PTR_ERR(clk
) == -EPROBE_DEFER
)
3099 * Here we make assumption that the device tree is
3100 * written correctly. So an error means that there is
3101 * no more parent. As we didn't exit yet, then the
3102 * previous parent are ready. If there is no clock
3103 * parent, no need to wait for them, then we can
3104 * consider their absence as being ready
3111 * of_clk_init() - Scan and init clock providers from the DT
3112 * @matches: array of compatible values and init functions for providers.
3114 * This function scans the device tree for matching clock providers
3115 * and calls their initialization functions. It also does it by trying
3116 * to follow the dependencies.
3118 void __init
of_clk_init(const struct of_device_id
*matches
)
3120 const struct of_device_id
*match
;
3121 struct device_node
*np
;
3122 struct clock_provider
*clk_provider
, *next
;
3127 matches
= &__clk_of_table
;
3129 /* First prepare the list of the clocks providers */
3130 for_each_matching_node_and_match(np
, matches
, &match
) {
3131 struct clock_provider
*parent
=
3132 kzalloc(sizeof(struct clock_provider
), GFP_KERNEL
);
3134 parent
->clk_init_cb
= match
->data
;
3136 list_add_tail(&parent
->node
, &clk_provider_list
);
3139 while (!list_empty(&clk_provider_list
)) {
3140 is_init_done
= false;
3141 list_for_each_entry_safe(clk_provider
, next
,
3142 &clk_provider_list
, node
) {
3143 if (force
|| parent_ready(clk_provider
->np
)) {
3145 clk_provider
->clk_init_cb(clk_provider
->np
);
3146 of_clk_set_defaults(clk_provider
->np
, true);
3148 list_del(&clk_provider
->node
);
3149 kfree(clk_provider
);
3150 is_init_done
= true;
3155 * We didn't manage to initialize any of the
3156 * remaining providers during the last loop, so now we
3157 * initialize all the remaining ones unconditionally
3158 * in case the clock parent was not mandatory