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>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
24 static DEFINE_SPINLOCK(enable_lock
);
25 static DEFINE_MUTEX(prepare_lock
);
27 static struct task_struct
*prepare_owner
;
28 static struct task_struct
*enable_owner
;
30 static int prepare_refcnt
;
31 static int enable_refcnt
;
33 static HLIST_HEAD(clk_root_list
);
34 static HLIST_HEAD(clk_orphan_list
);
35 static LIST_HEAD(clk_notifier_list
);
38 static void clk_prepare_lock(void)
40 if (!mutex_trylock(&prepare_lock
)) {
41 if (prepare_owner
== current
) {
45 mutex_lock(&prepare_lock
);
47 WARN_ON_ONCE(prepare_owner
!= NULL
);
48 WARN_ON_ONCE(prepare_refcnt
!= 0);
49 prepare_owner
= current
;
53 static void clk_prepare_unlock(void)
55 WARN_ON_ONCE(prepare_owner
!= current
);
56 WARN_ON_ONCE(prepare_refcnt
== 0);
61 mutex_unlock(&prepare_lock
);
64 static unsigned long clk_enable_lock(void)
68 if (!spin_trylock_irqsave(&enable_lock
, flags
)) {
69 if (enable_owner
== current
) {
73 spin_lock_irqsave(&enable_lock
, flags
);
75 WARN_ON_ONCE(enable_owner
!= NULL
);
76 WARN_ON_ONCE(enable_refcnt
!= 0);
77 enable_owner
= current
;
82 static void clk_enable_unlock(unsigned long flags
)
84 WARN_ON_ONCE(enable_owner
!= current
);
85 WARN_ON_ONCE(enable_refcnt
== 0);
90 spin_unlock_irqrestore(&enable_lock
, flags
);
93 /*** debugfs support ***/
95 #ifdef CONFIG_COMMON_CLK_DEBUG
96 #include <linux/debugfs.h>
98 static struct dentry
*rootdir
;
99 static struct dentry
*orphandir
;
100 static int inited
= 0;
102 static void clk_summary_show_one(struct seq_file
*s
, struct clk
*c
, int level
)
107 seq_printf(s
, "%*s%-*s %-11d %-12d %-10lu",
109 30 - level
* 3, c
->name
,
110 c
->enable_count
, c
->prepare_count
, clk_get_rate(c
));
114 static void clk_summary_show_subtree(struct seq_file
*s
, struct clk
*c
,
122 clk_summary_show_one(s
, c
, level
);
124 hlist_for_each_entry(child
, &c
->children
, child_node
)
125 clk_summary_show_subtree(s
, child
, level
+ 1);
128 static int clk_summary_show(struct seq_file
*s
, void *data
)
132 seq_printf(s
, " clock enable_cnt prepare_cnt rate\n");
133 seq_printf(s
, "---------------------------------------------------------------------\n");
137 hlist_for_each_entry(c
, &clk_root_list
, child_node
)
138 clk_summary_show_subtree(s
, c
, 0);
140 hlist_for_each_entry(c
, &clk_orphan_list
, child_node
)
141 clk_summary_show_subtree(s
, c
, 0);
143 clk_prepare_unlock();
149 static int clk_summary_open(struct inode
*inode
, struct file
*file
)
151 return single_open(file
, clk_summary_show
, inode
->i_private
);
154 static const struct file_operations clk_summary_fops
= {
155 .open
= clk_summary_open
,
158 .release
= single_release
,
161 static void clk_dump_one(struct seq_file
*s
, struct clk
*c
, int level
)
166 seq_printf(s
, "\"%s\": { ", c
->name
);
167 seq_printf(s
, "\"enable_count\": %d,", c
->enable_count
);
168 seq_printf(s
, "\"prepare_count\": %d,", c
->prepare_count
);
169 seq_printf(s
, "\"rate\": %lu", clk_get_rate(c
));
172 static void clk_dump_subtree(struct seq_file
*s
, struct clk
*c
, int level
)
179 clk_dump_one(s
, c
, level
);
181 hlist_for_each_entry(child
, &c
->children
, child_node
) {
183 clk_dump_subtree(s
, child
, level
+ 1);
189 static int clk_dump(struct seq_file
*s
, void *data
)
192 bool first_node
= true;
198 hlist_for_each_entry(c
, &clk_root_list
, child_node
) {
202 clk_dump_subtree(s
, c
, 0);
205 hlist_for_each_entry(c
, &clk_orphan_list
, child_node
) {
207 clk_dump_subtree(s
, c
, 0);
210 clk_prepare_unlock();
217 static int clk_dump_open(struct inode
*inode
, struct file
*file
)
219 return single_open(file
, clk_dump
, inode
->i_private
);
222 static const struct file_operations clk_dump_fops
= {
223 .open
= clk_dump_open
,
226 .release
= single_release
,
229 /* caller must hold prepare_lock */
230 static int clk_debug_create_one(struct clk
*clk
, struct dentry
*pdentry
)
235 if (!clk
|| !pdentry
) {
240 d
= debugfs_create_dir(clk
->name
, pdentry
);
246 d
= debugfs_create_u32("clk_rate", S_IRUGO
, clk
->dentry
,
251 d
= debugfs_create_x32("clk_flags", S_IRUGO
, clk
->dentry
,
256 d
= debugfs_create_u32("clk_prepare_count", S_IRUGO
, clk
->dentry
,
257 (u32
*)&clk
->prepare_count
);
261 d
= debugfs_create_u32("clk_enable_count", S_IRUGO
, clk
->dentry
,
262 (u32
*)&clk
->enable_count
);
266 d
= debugfs_create_u32("clk_notifier_count", S_IRUGO
, clk
->dentry
,
267 (u32
*)&clk
->notifier_count
);
275 debugfs_remove(clk
->dentry
);
280 /* caller must hold prepare_lock */
281 static int clk_debug_create_subtree(struct clk
*clk
, struct dentry
*pdentry
)
286 if (!clk
|| !pdentry
)
289 ret
= clk_debug_create_one(clk
, pdentry
);
294 hlist_for_each_entry(child
, &clk
->children
, child_node
)
295 clk_debug_create_subtree(child
, clk
->dentry
);
303 * clk_debug_register - add a clk node to the debugfs clk tree
304 * @clk: the clk being added to the debugfs clk tree
306 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
307 * initialized. Otherwise it bails out early since the debugfs clk tree
308 * will be created lazily by clk_debug_init as part of a late_initcall.
310 * Caller must hold prepare_lock. Only clk_init calls this function (so
311 * far) so this is taken care.
313 static int clk_debug_register(struct clk
*clk
)
316 struct dentry
*pdentry
;
322 parent
= clk
->parent
;
325 * Check to see if a clk is a root clk. Also check that it is
326 * safe to add this clk to debugfs
329 if (clk
->flags
& CLK_IS_ROOT
)
335 pdentry
= parent
->dentry
;
339 ret
= clk_debug_create_subtree(clk
, pdentry
);
346 * clk_debug_reparent - reparent clk node in the debugfs clk tree
347 * @clk: the clk being reparented
348 * @new_parent: the new clk parent, may be NULL
350 * Rename clk entry in the debugfs clk tree if debugfs has been
351 * initialized. Otherwise it bails out early since the debugfs clk tree
352 * will be created lazily by clk_debug_init as part of a late_initcall.
354 * Caller must hold prepare_lock.
356 static void clk_debug_reparent(struct clk
*clk
, struct clk
*new_parent
)
359 struct dentry
*new_parent_d
;
365 new_parent_d
= new_parent
->dentry
;
367 new_parent_d
= orphandir
;
369 d
= debugfs_rename(clk
->dentry
->d_parent
, clk
->dentry
,
370 new_parent_d
, clk
->name
);
374 pr_debug("%s: failed to rename debugfs entry for %s\n",
375 __func__
, clk
->name
);
379 * clk_debug_init - lazily create the debugfs clk tree visualization
381 * clks are often initialized very early during boot before memory can
382 * be dynamically allocated and well before debugfs is setup.
383 * clk_debug_init walks the clk tree hierarchy while holding
384 * prepare_lock and creates the topology as part of a late_initcall,
385 * thus insuring that clks initialized very early will still be
386 * represented in the debugfs clk tree. This function should only be
387 * called once at boot-time, and all other clks added dynamically will
388 * be done so with clk_debug_register.
390 static int __init
clk_debug_init(void)
395 rootdir
= debugfs_create_dir("clk", NULL
);
400 d
= debugfs_create_file("clk_summary", S_IRUGO
, rootdir
, NULL
,
405 d
= debugfs_create_file("clk_dump", S_IRUGO
, rootdir
, NULL
,
410 orphandir
= debugfs_create_dir("orphans", rootdir
);
417 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
418 clk_debug_create_subtree(clk
, rootdir
);
420 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
421 clk_debug_create_subtree(clk
, orphandir
);
425 clk_prepare_unlock();
429 late_initcall(clk_debug_init
);
431 static inline int clk_debug_register(struct clk
*clk
) { return 0; }
432 static inline void clk_debug_reparent(struct clk
*clk
, struct clk
*new_parent
)
437 /* caller must hold prepare_lock */
438 static void clk_unprepare_unused_subtree(struct clk
*clk
)
445 hlist_for_each_entry(child
, &clk
->children
, child_node
)
446 clk_unprepare_unused_subtree(child
);
448 if (clk
->prepare_count
)
451 if (clk
->flags
& CLK_IGNORE_UNUSED
)
454 if (__clk_is_prepared(clk
)) {
455 if (clk
->ops
->unprepare_unused
)
456 clk
->ops
->unprepare_unused(clk
->hw
);
457 else if (clk
->ops
->unprepare
)
458 clk
->ops
->unprepare(clk
->hw
);
461 EXPORT_SYMBOL_GPL(__clk_get_flags
);
463 /* caller must hold prepare_lock */
464 static void clk_disable_unused_subtree(struct clk
*clk
)
472 hlist_for_each_entry(child
, &clk
->children
, child_node
)
473 clk_disable_unused_subtree(child
);
475 flags
= clk_enable_lock();
477 if (clk
->enable_count
)
480 if (clk
->flags
& CLK_IGNORE_UNUSED
)
484 * some gate clocks have special needs during the disable-unused
485 * sequence. call .disable_unused if available, otherwise fall
488 if (__clk_is_enabled(clk
)) {
489 if (clk
->ops
->disable_unused
)
490 clk
->ops
->disable_unused(clk
->hw
);
491 else if (clk
->ops
->disable
)
492 clk
->ops
->disable(clk
->hw
);
496 clk_enable_unlock(flags
);
502 static bool clk_ignore_unused
;
503 static int __init
clk_ignore_unused_setup(char *__unused
)
505 clk_ignore_unused
= true;
508 __setup("clk_ignore_unused", clk_ignore_unused_setup
);
510 static int clk_disable_unused(void)
514 if (clk_ignore_unused
) {
515 pr_warn("clk: Not disabling unused clocks\n");
521 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
522 clk_disable_unused_subtree(clk
);
524 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
525 clk_disable_unused_subtree(clk
);
527 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
528 clk_unprepare_unused_subtree(clk
);
530 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
531 clk_unprepare_unused_subtree(clk
);
533 clk_prepare_unlock();
537 late_initcall_sync(clk_disable_unused
);
539 /*** helper functions ***/
541 const char *__clk_get_name(struct clk
*clk
)
543 return !clk
? NULL
: clk
->name
;
545 EXPORT_SYMBOL_GPL(__clk_get_name
);
547 struct clk_hw
*__clk_get_hw(struct clk
*clk
)
549 return !clk
? NULL
: clk
->hw
;
552 u8
__clk_get_num_parents(struct clk
*clk
)
554 return !clk
? 0 : clk
->num_parents
;
557 struct clk
*__clk_get_parent(struct clk
*clk
)
559 return !clk
? NULL
: clk
->parent
;
562 struct clk
*clk_get_parent_by_index(struct clk
*clk
, u8 index
)
564 if (!clk
|| index
>= clk
->num_parents
)
566 else if (!clk
->parents
)
567 return __clk_lookup(clk
->parent_names
[index
]);
568 else if (!clk
->parents
[index
])
569 return clk
->parents
[index
] =
570 __clk_lookup(clk
->parent_names
[index
]);
572 return clk
->parents
[index
];
575 unsigned int __clk_get_enable_count(struct clk
*clk
)
577 return !clk
? 0 : clk
->enable_count
;
580 unsigned int __clk_get_prepare_count(struct clk
*clk
)
582 return !clk
? 0 : clk
->prepare_count
;
585 unsigned long __clk_get_rate(struct clk
*clk
)
596 if (clk
->flags
& CLK_IS_ROOT
)
606 unsigned long __clk_get_flags(struct clk
*clk
)
608 return !clk
? 0 : clk
->flags
;
611 bool __clk_is_prepared(struct clk
*clk
)
619 * .is_prepared is optional for clocks that can prepare
620 * fall back to software usage counter if it is missing
622 if (!clk
->ops
->is_prepared
) {
623 ret
= clk
->prepare_count
? 1 : 0;
627 ret
= clk
->ops
->is_prepared(clk
->hw
);
632 bool __clk_is_enabled(struct clk
*clk
)
640 * .is_enabled is only mandatory for clocks that gate
641 * fall back to software usage counter if .is_enabled is missing
643 if (!clk
->ops
->is_enabled
) {
644 ret
= clk
->enable_count
? 1 : 0;
648 ret
= clk
->ops
->is_enabled(clk
->hw
);
653 static struct clk
*__clk_lookup_subtree(const char *name
, struct clk
*clk
)
658 if (!strcmp(clk
->name
, name
))
661 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
662 ret
= __clk_lookup_subtree(name
, child
);
670 struct clk
*__clk_lookup(const char *name
)
672 struct clk
*root_clk
;
678 /* search the 'proper' clk tree first */
679 hlist_for_each_entry(root_clk
, &clk_root_list
, child_node
) {
680 ret
= __clk_lookup_subtree(name
, root_clk
);
685 /* if not found, then search the orphan tree */
686 hlist_for_each_entry(root_clk
, &clk_orphan_list
, child_node
) {
687 ret
= __clk_lookup_subtree(name
, root_clk
);
696 * Helper for finding best parent to provide a given frequency. This can be used
697 * directly as a determine_rate callback (e.g. for a mux), or from a more
698 * complex clock that may combine a mux with other operations.
700 long __clk_mux_determine_rate(struct clk_hw
*hw
, unsigned long rate
,
701 unsigned long *best_parent_rate
,
702 struct clk
**best_parent_p
)
704 struct clk
*clk
= hw
->clk
, *parent
, *best_parent
= NULL
;
706 unsigned long parent_rate
, best
= 0;
708 /* if NO_REPARENT flag set, pass through to current parent */
709 if (clk
->flags
& CLK_SET_RATE_NO_REPARENT
) {
710 parent
= clk
->parent
;
711 if (clk
->flags
& CLK_SET_RATE_PARENT
)
712 best
= __clk_round_rate(parent
, rate
);
714 best
= __clk_get_rate(parent
);
716 best
= __clk_get_rate(clk
);
720 /* find the parent that can provide the fastest rate <= rate */
721 num_parents
= clk
->num_parents
;
722 for (i
= 0; i
< num_parents
; i
++) {
723 parent
= clk_get_parent_by_index(clk
, i
);
726 if (clk
->flags
& CLK_SET_RATE_PARENT
)
727 parent_rate
= __clk_round_rate(parent
, rate
);
729 parent_rate
= __clk_get_rate(parent
);
730 if (parent_rate
<= rate
&& parent_rate
> best
) {
731 best_parent
= parent
;
738 *best_parent_p
= best_parent
;
739 *best_parent_rate
= best
;
746 void __clk_unprepare(struct clk
*clk
)
751 if (WARN_ON(clk
->prepare_count
== 0))
754 if (--clk
->prepare_count
> 0)
757 WARN_ON(clk
->enable_count
> 0);
759 if (clk
->ops
->unprepare
)
760 clk
->ops
->unprepare(clk
->hw
);
762 __clk_unprepare(clk
->parent
);
766 * clk_unprepare - undo preparation of a clock source
767 * @clk: the clk being unprepared
769 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
770 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
771 * if the operation may sleep. One example is a clk which is accessed over
772 * I2c. In the complex case a clk gate operation may require a fast and a slow
773 * part. It is this reason that clk_unprepare and clk_disable are not mutually
774 * exclusive. In fact clk_disable must be called before clk_unprepare.
776 void clk_unprepare(struct clk
*clk
)
779 __clk_unprepare(clk
);
780 clk_prepare_unlock();
782 EXPORT_SYMBOL_GPL(clk_unprepare
);
784 int __clk_prepare(struct clk
*clk
)
791 if (clk
->prepare_count
== 0) {
792 ret
= __clk_prepare(clk
->parent
);
796 if (clk
->ops
->prepare
) {
797 ret
= clk
->ops
->prepare(clk
->hw
);
799 __clk_unprepare(clk
->parent
);
805 clk
->prepare_count
++;
811 * clk_prepare - prepare a clock source
812 * @clk: the clk being prepared
814 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
815 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
816 * operation may sleep. One example is a clk which is accessed over I2c. In
817 * the complex case a clk ungate operation may require a fast and a slow part.
818 * It is this reason that clk_prepare and clk_enable are not mutually
819 * exclusive. In fact clk_prepare must be called before clk_enable.
820 * Returns 0 on success, -EERROR otherwise.
822 int clk_prepare(struct clk
*clk
)
827 ret
= __clk_prepare(clk
);
828 clk_prepare_unlock();
832 EXPORT_SYMBOL_GPL(clk_prepare
);
834 static void __clk_disable(struct clk
*clk
)
839 if (WARN_ON(IS_ERR(clk
)))
842 if (WARN_ON(clk
->enable_count
== 0))
845 if (--clk
->enable_count
> 0)
848 if (clk
->ops
->disable
)
849 clk
->ops
->disable(clk
->hw
);
851 __clk_disable(clk
->parent
);
855 * clk_disable - gate a clock
856 * @clk: the clk being gated
858 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
859 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
860 * clk if the operation is fast and will never sleep. One example is a
861 * SoC-internal clk which is controlled via simple register writes. In the
862 * complex case a clk gate operation may require a fast and a slow part. It is
863 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
864 * In fact clk_disable must be called before clk_unprepare.
866 void clk_disable(struct clk
*clk
)
870 flags
= clk_enable_lock();
872 clk_enable_unlock(flags
);
874 EXPORT_SYMBOL_GPL(clk_disable
);
876 static int __clk_enable(struct clk
*clk
)
883 if (WARN_ON(clk
->prepare_count
== 0))
886 if (clk
->enable_count
== 0) {
887 ret
= __clk_enable(clk
->parent
);
892 if (clk
->ops
->enable
) {
893 ret
= clk
->ops
->enable(clk
->hw
);
895 __clk_disable(clk
->parent
);
906 * clk_enable - ungate a clock
907 * @clk: the clk being ungated
909 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
910 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
911 * if the operation will never sleep. One example is a SoC-internal clk which
912 * is controlled via simple register writes. In the complex case a clk ungate
913 * operation may require a fast and a slow part. It is this reason that
914 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
915 * must be called before clk_enable. Returns 0 on success, -EERROR
918 int clk_enable(struct clk
*clk
)
923 flags
= clk_enable_lock();
924 ret
= __clk_enable(clk
);
925 clk_enable_unlock(flags
);
929 EXPORT_SYMBOL_GPL(clk_enable
);
932 * __clk_round_rate - round the given rate for a clk
933 * @clk: round the rate of this clock
934 * @rate: the rate which is to be rounded
936 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
938 unsigned long __clk_round_rate(struct clk
*clk
, unsigned long rate
)
940 unsigned long parent_rate
= 0;
946 parent
= clk
->parent
;
948 parent_rate
= parent
->rate
;
950 if (clk
->ops
->determine_rate
)
951 return clk
->ops
->determine_rate(clk
->hw
, rate
, &parent_rate
,
953 else if (clk
->ops
->round_rate
)
954 return clk
->ops
->round_rate(clk
->hw
, rate
, &parent_rate
);
955 else if (clk
->flags
& CLK_SET_RATE_PARENT
)
956 return __clk_round_rate(clk
->parent
, rate
);
962 * clk_round_rate - round the given rate for a clk
963 * @clk: the clk for which we are rounding a rate
964 * @rate: the rate which is to be rounded
966 * Takes in a rate as input and rounds it to a rate that the clk can actually
967 * use which is then returned. If clk doesn't support round_rate operation
968 * then the parent rate is returned.
970 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
975 ret
= __clk_round_rate(clk
, rate
);
976 clk_prepare_unlock();
980 EXPORT_SYMBOL_GPL(clk_round_rate
);
983 * __clk_notify - call clk notifier chain
984 * @clk: struct clk * that is changing rate
985 * @msg: clk notifier type (see include/linux/clk.h)
986 * @old_rate: old clk rate
987 * @new_rate: new clk rate
989 * Triggers a notifier call chain on the clk rate-change notification
990 * for 'clk'. Passes a pointer to the struct clk and the previous
991 * and current rates to the notifier callback. Intended to be called by
992 * internal clock code only. Returns NOTIFY_DONE from the last driver
993 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
994 * a driver returns that.
996 static int __clk_notify(struct clk
*clk
, unsigned long msg
,
997 unsigned long old_rate
, unsigned long new_rate
)
999 struct clk_notifier
*cn
;
1000 struct clk_notifier_data cnd
;
1001 int ret
= NOTIFY_DONE
;
1004 cnd
.old_rate
= old_rate
;
1005 cnd
.new_rate
= new_rate
;
1007 list_for_each_entry(cn
, &clk_notifier_list
, node
) {
1008 if (cn
->clk
== clk
) {
1009 ret
= srcu_notifier_call_chain(&cn
->notifier_head
, msg
,
1019 * __clk_recalc_rates
1020 * @clk: first clk in the subtree
1021 * @msg: notification type (see include/linux/clk.h)
1023 * Walks the subtree of clks starting with clk and recalculates rates as it
1024 * goes. Note that if a clk does not implement the .recalc_rate callback then
1025 * it is assumed that the clock will take on the rate of its parent.
1027 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1030 * Caller must hold prepare_lock.
1032 static void __clk_recalc_rates(struct clk
*clk
, unsigned long msg
)
1034 unsigned long old_rate
;
1035 unsigned long parent_rate
= 0;
1038 old_rate
= clk
->rate
;
1041 parent_rate
= clk
->parent
->rate
;
1043 if (clk
->ops
->recalc_rate
)
1044 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
1046 clk
->rate
= parent_rate
;
1049 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1050 * & ABORT_RATE_CHANGE notifiers
1052 if (clk
->notifier_count
&& msg
)
1053 __clk_notify(clk
, msg
, old_rate
, clk
->rate
);
1055 hlist_for_each_entry(child
, &clk
->children
, child_node
)
1056 __clk_recalc_rates(child
, msg
);
1060 * clk_get_rate - return the rate of clk
1061 * @clk: the clk whose rate is being returned
1063 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1064 * is set, which means a recalc_rate will be issued.
1065 * If clk is NULL then returns 0.
1067 unsigned long clk_get_rate(struct clk
*clk
)
1073 if (clk
&& (clk
->flags
& CLK_GET_RATE_NOCACHE
))
1074 __clk_recalc_rates(clk
, 0);
1076 rate
= __clk_get_rate(clk
);
1077 clk_prepare_unlock();
1081 EXPORT_SYMBOL_GPL(clk_get_rate
);
1083 static u8
clk_fetch_parent_index(struct clk
*clk
, struct clk
*parent
)
1088 clk
->parents
= kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1092 * find index of new parent clock using cached parent ptrs,
1093 * or if not yet cached, use string name comparison and cache
1094 * them now to avoid future calls to __clk_lookup.
1096 for (i
= 0; i
< clk
->num_parents
; i
++) {
1097 if (clk
->parents
&& clk
->parents
[i
] == parent
)
1099 else if (!strcmp(clk
->parent_names
[i
], parent
->name
)) {
1101 clk
->parents
[i
] = __clk_lookup(parent
->name
);
1109 static void clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1111 /* avoid duplicate POST_RATE_CHANGE notifications */
1112 if (new_parent
->new_child
== clk
)
1113 new_parent
->new_child
= NULL
;
1115 hlist_del(&clk
->child_node
);
1118 hlist_add_head(&clk
->child_node
, &new_parent
->children
);
1120 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1122 clk
->parent
= new_parent
;
1125 static int __clk_set_parent(struct clk
*clk
, struct clk
*parent
, u8 p_index
)
1127 unsigned long flags
;
1129 struct clk
*old_parent
= clk
->parent
;
1132 * Migrate prepare state between parents and prevent race with
1135 * If the clock is not prepared, then a race with
1136 * clk_enable/disable() is impossible since we already have the
1137 * prepare lock (future calls to clk_enable() need to be preceded by
1140 * If the clock is prepared, migrate the prepared state to the new
1141 * parent and also protect against a race with clk_enable() by
1142 * forcing the clock and the new parent on. This ensures that all
1143 * future calls to clk_enable() are practically NOPs with respect to
1144 * hardware and software states.
1146 * See also: Comment for clk_set_parent() below.
1148 if (clk
->prepare_count
) {
1149 __clk_prepare(parent
);
1154 /* update the clk tree topology */
1155 flags
= clk_enable_lock();
1156 clk_reparent(clk
, parent
);
1157 clk_enable_unlock(flags
);
1159 /* change clock input source */
1160 if (parent
&& clk
->ops
->set_parent
)
1161 ret
= clk
->ops
->set_parent(clk
->hw
, p_index
);
1164 flags
= clk_enable_lock();
1165 clk_reparent(clk
, old_parent
);
1166 clk_enable_unlock(flags
);
1168 if (clk
->prepare_count
) {
1170 clk_disable(parent
);
1171 __clk_unprepare(parent
);
1177 * Finish the migration of prepare state and undo the changes done
1178 * for preventing a race with clk_enable().
1180 if (clk
->prepare_count
) {
1182 clk_disable(old_parent
);
1183 __clk_unprepare(old_parent
);
1186 /* update debugfs with new clk tree topology */
1187 clk_debug_reparent(clk
, parent
);
1192 * __clk_speculate_rates
1193 * @clk: first clk in the subtree
1194 * @parent_rate: the "future" rate of clk's parent
1196 * Walks the subtree of clks starting with clk, speculating rates as it
1197 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1199 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1200 * pre-rate change notifications and returns early if no clks in the
1201 * subtree have subscribed to the notifications. Note that if a clk does not
1202 * implement the .recalc_rate callback then it is assumed that the clock will
1203 * take on the rate of its parent.
1205 * Caller must hold prepare_lock.
1207 static int __clk_speculate_rates(struct clk
*clk
, unsigned long parent_rate
)
1210 unsigned long new_rate
;
1211 int ret
= NOTIFY_DONE
;
1213 if (clk
->ops
->recalc_rate
)
1214 new_rate
= clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
1216 new_rate
= parent_rate
;
1218 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1219 if (clk
->notifier_count
)
1220 ret
= __clk_notify(clk
, PRE_RATE_CHANGE
, clk
->rate
, new_rate
);
1222 if (ret
& NOTIFY_STOP_MASK
)
1225 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1226 ret
= __clk_speculate_rates(child
, new_rate
);
1227 if (ret
& NOTIFY_STOP_MASK
)
1235 static void clk_calc_subtree(struct clk
*clk
, unsigned long new_rate
,
1236 struct clk
*new_parent
, u8 p_index
)
1240 clk
->new_rate
= new_rate
;
1241 clk
->new_parent
= new_parent
;
1242 clk
->new_parent_index
= p_index
;
1243 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1244 clk
->new_child
= NULL
;
1245 if (new_parent
&& new_parent
!= clk
->parent
)
1246 new_parent
->new_child
= clk
;
1248 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1249 if (child
->ops
->recalc_rate
)
1250 child
->new_rate
= child
->ops
->recalc_rate(child
->hw
, new_rate
);
1252 child
->new_rate
= new_rate
;
1253 clk_calc_subtree(child
, child
->new_rate
, NULL
, 0);
1258 * calculate the new rates returning the topmost clock that has to be
1261 static struct clk
*clk_calc_new_rates(struct clk
*clk
, unsigned long rate
)
1263 struct clk
*top
= clk
;
1264 struct clk
*old_parent
, *parent
;
1265 unsigned long best_parent_rate
= 0;
1266 unsigned long new_rate
;
1270 if (IS_ERR_OR_NULL(clk
))
1273 /* save parent rate, if it exists */
1274 parent
= old_parent
= clk
->parent
;
1276 best_parent_rate
= parent
->rate
;
1278 /* find the closest rate and parent clk/rate */
1279 if (clk
->ops
->determine_rate
) {
1280 new_rate
= clk
->ops
->determine_rate(clk
->hw
, rate
,
1283 } else if (clk
->ops
->round_rate
) {
1284 new_rate
= clk
->ops
->round_rate(clk
->hw
, rate
,
1286 } else if (!parent
|| !(clk
->flags
& CLK_SET_RATE_PARENT
)) {
1287 /* pass-through clock without adjustable parent */
1288 clk
->new_rate
= clk
->rate
;
1291 /* pass-through clock with adjustable parent */
1292 top
= clk_calc_new_rates(parent
, rate
);
1293 new_rate
= parent
->new_rate
;
1297 /* some clocks must be gated to change parent */
1298 if (parent
!= old_parent
&&
1299 (clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1300 pr_debug("%s: %s not gated but wants to reparent\n",
1301 __func__
, clk
->name
);
1305 /* try finding the new parent index */
1307 p_index
= clk_fetch_parent_index(clk
, parent
);
1308 if (p_index
== clk
->num_parents
) {
1309 pr_debug("%s: clk %s can not be parent of clk %s\n",
1310 __func__
, parent
->name
, clk
->name
);
1315 if ((clk
->flags
& CLK_SET_RATE_PARENT
) && parent
&&
1316 best_parent_rate
!= parent
->rate
)
1317 top
= clk_calc_new_rates(parent
, best_parent_rate
);
1320 clk_calc_subtree(clk
, new_rate
, parent
, p_index
);
1326 * Notify about rate changes in a subtree. Always walk down the whole tree
1327 * so that in case of an error we can walk down the whole tree again and
1330 static struct clk
*clk_propagate_rate_change(struct clk
*clk
, unsigned long event
)
1332 struct clk
*child
, *tmp_clk
, *fail_clk
= NULL
;
1333 int ret
= NOTIFY_DONE
;
1335 if (clk
->rate
== clk
->new_rate
)
1338 if (clk
->notifier_count
) {
1339 ret
= __clk_notify(clk
, event
, clk
->rate
, clk
->new_rate
);
1340 if (ret
& NOTIFY_STOP_MASK
)
1344 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1345 /* Skip children who will be reparented to another clock */
1346 if (child
->new_parent
&& child
->new_parent
!= clk
)
1348 tmp_clk
= clk_propagate_rate_change(child
, event
);
1353 /* handle the new child who might not be in clk->children yet */
1354 if (clk
->new_child
) {
1355 tmp_clk
= clk_propagate_rate_change(clk
->new_child
, event
);
1364 * walk down a subtree and set the new rates notifying the rate
1367 static void clk_change_rate(struct clk
*clk
)
1370 unsigned long old_rate
;
1371 unsigned long best_parent_rate
= 0;
1373 old_rate
= clk
->rate
;
1376 if (clk
->new_parent
&& clk
->new_parent
!= clk
->parent
)
1377 __clk_set_parent(clk
, clk
->new_parent
, clk
->new_parent_index
);
1380 best_parent_rate
= clk
->parent
->rate
;
1382 if (clk
->ops
->set_rate
)
1383 clk
->ops
->set_rate(clk
->hw
, clk
->new_rate
, best_parent_rate
);
1385 if (clk
->ops
->recalc_rate
)
1386 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
, best_parent_rate
);
1388 clk
->rate
= best_parent_rate
;
1390 if (clk
->notifier_count
&& old_rate
!= clk
->rate
)
1391 __clk_notify(clk
, POST_RATE_CHANGE
, old_rate
, clk
->rate
);
1393 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1394 /* Skip children who will be reparented to another clock */
1395 if (child
->new_parent
&& child
->new_parent
!= clk
)
1397 clk_change_rate(child
);
1400 /* handle the new child who might not be in clk->children yet */
1402 clk_change_rate(clk
->new_child
);
1406 * clk_set_rate - specify a new rate for clk
1407 * @clk: the clk whose rate is being changed
1408 * @rate: the new rate for clk
1410 * In the simplest case clk_set_rate will only adjust the rate of clk.
1412 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1413 * propagate up to clk's parent; whether or not this happens depends on the
1414 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1415 * after calling .round_rate then upstream parent propagation is ignored. If
1416 * *parent_rate comes back with a new rate for clk's parent then we propagate
1417 * up to clk's parent and set its rate. Upward propagation will continue
1418 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1419 * .round_rate stops requesting changes to clk's parent_rate.
1421 * Rate changes are accomplished via tree traversal that also recalculates the
1422 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1424 * Returns 0 on success, -EERROR otherwise.
1426 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
1428 struct clk
*top
, *fail_clk
;
1434 /* prevent racing with updates to the clock topology */
1437 /* bail early if nothing to do */
1438 if (rate
== clk_get_rate(clk
))
1441 if ((clk
->flags
& CLK_SET_RATE_GATE
) && clk
->prepare_count
) {
1446 /* calculate new rates and get the topmost changed clock */
1447 top
= clk_calc_new_rates(clk
, rate
);
1453 /* notify that we are about to change rates */
1454 fail_clk
= clk_propagate_rate_change(top
, PRE_RATE_CHANGE
);
1456 pr_warn("%s: failed to set %s rate\n", __func__
,
1458 clk_propagate_rate_change(top
, ABORT_RATE_CHANGE
);
1463 /* change the rates */
1464 clk_change_rate(top
);
1467 clk_prepare_unlock();
1471 EXPORT_SYMBOL_GPL(clk_set_rate
);
1474 * clk_get_parent - return the parent of a clk
1475 * @clk: the clk whose parent gets returned
1477 * Simply returns clk->parent. Returns NULL if clk is NULL.
1479 struct clk
*clk_get_parent(struct clk
*clk
)
1484 parent
= __clk_get_parent(clk
);
1485 clk_prepare_unlock();
1489 EXPORT_SYMBOL_GPL(clk_get_parent
);
1492 * .get_parent is mandatory for clocks with multiple possible parents. It is
1493 * optional for single-parent clocks. Always call .get_parent if it is
1494 * available and WARN if it is missing for multi-parent clocks.
1496 * For single-parent clocks without .get_parent, first check to see if the
1497 * .parents array exists, and if so use it to avoid an expensive tree
1498 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1500 static struct clk
*__clk_init_parent(struct clk
*clk
)
1502 struct clk
*ret
= NULL
;
1505 /* handle the trivial cases */
1507 if (!clk
->num_parents
)
1510 if (clk
->num_parents
== 1) {
1511 if (IS_ERR_OR_NULL(clk
->parent
))
1512 ret
= clk
->parent
= __clk_lookup(clk
->parent_names
[0]);
1517 if (!clk
->ops
->get_parent
) {
1518 WARN(!clk
->ops
->get_parent
,
1519 "%s: multi-parent clocks must implement .get_parent\n",
1525 * Do our best to cache parent clocks in clk->parents. This prevents
1526 * unnecessary and expensive calls to __clk_lookup. We don't set
1527 * clk->parent here; that is done by the calling function
1530 index
= clk
->ops
->get_parent(clk
->hw
);
1534 kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1537 ret
= clk_get_parent_by_index(clk
, index
);
1543 void __clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1545 clk_reparent(clk
, new_parent
);
1546 clk_debug_reparent(clk
, new_parent
);
1547 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1551 * clk_set_parent - switch the parent of a mux clk
1552 * @clk: the mux clk whose input we are switching
1553 * @parent: the new input to clk
1555 * Re-parent clk to use parent as its new input source. If clk is in
1556 * prepared state, the clk will get enabled for the duration of this call. If
1557 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1558 * that, the reparenting is glitchy in hardware, etc), use the
1559 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1561 * After successfully changing clk's parent clk_set_parent will update the
1562 * clk topology, sysfs topology and propagate rate recalculation via
1563 * __clk_recalc_rates.
1565 * Returns 0 on success, -EERROR otherwise.
1567 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
1571 unsigned long p_rate
= 0;
1579 /* verify ops for for multi-parent clks */
1580 if ((clk
->num_parents
> 1) && (!clk
->ops
->set_parent
))
1583 /* prevent racing with updates to the clock topology */
1586 if (clk
->parent
== parent
)
1589 /* check that we are allowed to re-parent if the clock is in use */
1590 if ((clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1595 /* try finding the new parent index */
1597 p_index
= clk_fetch_parent_index(clk
, parent
);
1598 p_rate
= parent
->rate
;
1599 if (p_index
== clk
->num_parents
) {
1600 pr_debug("%s: clk %s can not be parent of clk %s\n",
1601 __func__
, parent
->name
, clk
->name
);
1607 /* propagate PRE_RATE_CHANGE notifications */
1608 ret
= __clk_speculate_rates(clk
, p_rate
);
1610 /* abort if a driver objects */
1611 if (ret
& NOTIFY_STOP_MASK
)
1614 /* do the re-parent */
1615 ret
= __clk_set_parent(clk
, parent
, p_index
);
1617 /* propagate rate recalculation accordingly */
1619 __clk_recalc_rates(clk
, ABORT_RATE_CHANGE
);
1621 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1624 clk_prepare_unlock();
1628 EXPORT_SYMBOL_GPL(clk_set_parent
);
1631 * __clk_init - initialize the data structures in a struct clk
1632 * @dev: device initializing this clk, placeholder for now
1633 * @clk: clk being initialized
1635 * Initializes the lists in struct clk, queries the hardware for the
1636 * parent and rate and sets them both.
1638 int __clk_init(struct device
*dev
, struct clk
*clk
)
1642 struct hlist_node
*tmp2
;
1649 /* check to see if a clock with this name is already registered */
1650 if (__clk_lookup(clk
->name
)) {
1651 pr_debug("%s: clk %s already initialized\n",
1652 __func__
, clk
->name
);
1657 /* check that clk_ops are sane. See Documentation/clk.txt */
1658 if (clk
->ops
->set_rate
&&
1659 !((clk
->ops
->round_rate
|| clk
->ops
->determine_rate
) &&
1660 clk
->ops
->recalc_rate
)) {
1661 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1662 __func__
, clk
->name
);
1667 if (clk
->ops
->set_parent
&& !clk
->ops
->get_parent
) {
1668 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1669 __func__
, clk
->name
);
1674 /* throw a WARN if any entries in parent_names are NULL */
1675 for (i
= 0; i
< clk
->num_parents
; i
++)
1676 WARN(!clk
->parent_names
[i
],
1677 "%s: invalid NULL in %s's .parent_names\n",
1678 __func__
, clk
->name
);
1681 * Allocate an array of struct clk *'s to avoid unnecessary string
1682 * look-ups of clk's possible parents. This can fail for clocks passed
1683 * in to clk_init during early boot; thus any access to clk->parents[]
1684 * must always check for a NULL pointer and try to populate it if
1687 * If clk->parents is not NULL we skip this entire block. This allows
1688 * for clock drivers to statically initialize clk->parents.
1690 if (clk
->num_parents
> 1 && !clk
->parents
) {
1691 clk
->parents
= kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1694 * __clk_lookup returns NULL for parents that have not been
1695 * clk_init'd; thus any access to clk->parents[] must check
1696 * for a NULL pointer. We can always perform lazy lookups for
1697 * missing parents later on.
1700 for (i
= 0; i
< clk
->num_parents
; i
++)
1702 __clk_lookup(clk
->parent_names
[i
]);
1705 clk
->parent
= __clk_init_parent(clk
);
1708 * Populate clk->parent if parent has already been __clk_init'd. If
1709 * parent has not yet been __clk_init'd then place clk in the orphan
1710 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1713 * Every time a new clk is clk_init'd then we walk the list of orphan
1714 * clocks and re-parent any that are children of the clock currently
1718 hlist_add_head(&clk
->child_node
,
1719 &clk
->parent
->children
);
1720 else if (clk
->flags
& CLK_IS_ROOT
)
1721 hlist_add_head(&clk
->child_node
, &clk_root_list
);
1723 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1726 * Set clk's rate. The preferred method is to use .recalc_rate. For
1727 * simple clocks and lazy developers the default fallback is to use the
1728 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1729 * then rate is set to zero.
1731 if (clk
->ops
->recalc_rate
)
1732 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
,
1733 __clk_get_rate(clk
->parent
));
1734 else if (clk
->parent
)
1735 clk
->rate
= clk
->parent
->rate
;
1740 * walk the list of orphan clocks and reparent any that are children of
1743 hlist_for_each_entry_safe(orphan
, tmp2
, &clk_orphan_list
, child_node
) {
1744 if (orphan
->ops
->get_parent
) {
1745 i
= orphan
->ops
->get_parent(orphan
->hw
);
1746 if (!strcmp(clk
->name
, orphan
->parent_names
[i
]))
1747 __clk_reparent(orphan
, clk
);
1751 for (i
= 0; i
< orphan
->num_parents
; i
++)
1752 if (!strcmp(clk
->name
, orphan
->parent_names
[i
])) {
1753 __clk_reparent(orphan
, clk
);
1759 * optional platform-specific magic
1761 * The .init callback is not used by any of the basic clock types, but
1762 * exists for weird hardware that must perform initialization magic.
1763 * Please consider other ways of solving initialization problems before
1764 * using this callback, as its use is discouraged.
1767 clk
->ops
->init(clk
->hw
);
1769 clk_debug_register(clk
);
1772 clk_prepare_unlock();
1778 * __clk_register - register a clock and return a cookie.
1780 * Same as clk_register, except that the .clk field inside hw shall point to a
1781 * preallocated (generally statically allocated) struct clk. None of the fields
1782 * of the struct clk need to be initialized.
1784 * The data pointed to by .init and .clk field shall NOT be marked as init
1787 * __clk_register is only exposed via clk-private.h and is intended for use with
1788 * very large numbers of clocks that need to be statically initialized. It is
1789 * a layering violation to include clk-private.h from any code which implements
1790 * a clock's .ops; as such any statically initialized clock data MUST be in a
1791 * separate C file from the logic that implements its operations. Returns 0
1792 * on success, otherwise an error code.
1794 struct clk
*__clk_register(struct device
*dev
, struct clk_hw
*hw
)
1800 clk
->name
= hw
->init
->name
;
1801 clk
->ops
= hw
->init
->ops
;
1803 clk
->flags
= hw
->init
->flags
;
1804 clk
->parent_names
= hw
->init
->parent_names
;
1805 clk
->num_parents
= hw
->init
->num_parents
;
1807 ret
= __clk_init(dev
, clk
);
1809 return ERR_PTR(ret
);
1813 EXPORT_SYMBOL_GPL(__clk_register
);
1815 static int _clk_register(struct device
*dev
, struct clk_hw
*hw
, struct clk
*clk
)
1819 clk
->name
= kstrdup(hw
->init
->name
, GFP_KERNEL
);
1821 pr_err("%s: could not allocate clk->name\n", __func__
);
1825 clk
->ops
= hw
->init
->ops
;
1827 clk
->flags
= hw
->init
->flags
;
1828 clk
->num_parents
= hw
->init
->num_parents
;
1831 /* allocate local copy in case parent_names is __initdata */
1832 clk
->parent_names
= kzalloc((sizeof(char*) * clk
->num_parents
),
1835 if (!clk
->parent_names
) {
1836 pr_err("%s: could not allocate clk->parent_names\n", __func__
);
1838 goto fail_parent_names
;
1842 /* copy each string name in case parent_names is __initdata */
1843 for (i
= 0; i
< clk
->num_parents
; i
++) {
1844 clk
->parent_names
[i
] = kstrdup(hw
->init
->parent_names
[i
],
1846 if (!clk
->parent_names
[i
]) {
1847 pr_err("%s: could not copy parent_names\n", __func__
);
1849 goto fail_parent_names_copy
;
1853 ret
= __clk_init(dev
, clk
);
1857 fail_parent_names_copy
:
1859 kfree(clk
->parent_names
[i
]);
1860 kfree(clk
->parent_names
);
1868 * clk_register - allocate a new clock, register it and return an opaque cookie
1869 * @dev: device that is registering this clock
1870 * @hw: link to hardware-specific clock data
1872 * clk_register is the primary interface for populating the clock tree with new
1873 * clock nodes. It returns a pointer to the newly allocated struct clk which
1874 * cannot be dereferenced by driver code but may be used in conjuction with the
1875 * rest of the clock API. In the event of an error clk_register will return an
1876 * error code; drivers must test for an error code after calling clk_register.
1878 struct clk
*clk_register(struct device
*dev
, struct clk_hw
*hw
)
1883 clk
= kzalloc(sizeof(*clk
), GFP_KERNEL
);
1885 pr_err("%s: could not allocate clk\n", __func__
);
1890 ret
= _clk_register(dev
, hw
, clk
);
1896 return ERR_PTR(ret
);
1898 EXPORT_SYMBOL_GPL(clk_register
);
1901 * clk_unregister - unregister a currently registered clock
1902 * @clk: clock to unregister
1904 * Currently unimplemented.
1906 void clk_unregister(struct clk
*clk
) {}
1907 EXPORT_SYMBOL_GPL(clk_unregister
);
1909 static void devm_clk_release(struct device
*dev
, void *res
)
1911 clk_unregister(res
);
1915 * devm_clk_register - resource managed clk_register()
1916 * @dev: device that is registering this clock
1917 * @hw: link to hardware-specific clock data
1919 * Managed clk_register(). Clocks returned from this function are
1920 * automatically clk_unregister()ed on driver detach. See clk_register() for
1923 struct clk
*devm_clk_register(struct device
*dev
, struct clk_hw
*hw
)
1928 clk
= devres_alloc(devm_clk_release
, sizeof(*clk
), GFP_KERNEL
);
1930 return ERR_PTR(-ENOMEM
);
1932 ret
= _clk_register(dev
, hw
, clk
);
1934 devres_add(dev
, clk
);
1942 EXPORT_SYMBOL_GPL(devm_clk_register
);
1944 static int devm_clk_match(struct device
*dev
, void *res
, void *data
)
1946 struct clk
*c
= res
;
1953 * devm_clk_unregister - resource managed clk_unregister()
1954 * @clk: clock to unregister
1956 * Deallocate a clock allocated with devm_clk_register(). Normally
1957 * this function will not need to be called and the resource management
1958 * code will ensure that the resource is freed.
1960 void devm_clk_unregister(struct device
*dev
, struct clk
*clk
)
1962 WARN_ON(devres_release(dev
, devm_clk_release
, devm_clk_match
, clk
));
1964 EXPORT_SYMBOL_GPL(devm_clk_unregister
);
1966 /*** clk rate change notifiers ***/
1969 * clk_notifier_register - add a clk rate change notifier
1970 * @clk: struct clk * to watch
1971 * @nb: struct notifier_block * with callback info
1973 * Request notification when clk's rate changes. This uses an SRCU
1974 * notifier because we want it to block and notifier unregistrations are
1975 * uncommon. The callbacks associated with the notifier must not
1976 * re-enter into the clk framework by calling any top-level clk APIs;
1977 * this will cause a nested prepare_lock mutex.
1979 * Pre-change notifier callbacks will be passed the current, pre-change
1980 * rate of the clk via struct clk_notifier_data.old_rate. The new,
1981 * post-change rate of the clk is passed via struct
1982 * clk_notifier_data.new_rate.
1984 * Post-change notifiers will pass the now-current, post-change rate of
1985 * the clk in both struct clk_notifier_data.old_rate and struct
1986 * clk_notifier_data.new_rate.
1988 * Abort-change notifiers are effectively the opposite of pre-change
1989 * notifiers: the original pre-change clk rate is passed in via struct
1990 * clk_notifier_data.new_rate and the failed post-change rate is passed
1991 * in via struct clk_notifier_data.old_rate.
1993 * clk_notifier_register() must be called from non-atomic context.
1994 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1995 * allocation failure; otherwise, passes along the return value of
1996 * srcu_notifier_chain_register().
1998 int clk_notifier_register(struct clk
*clk
, struct notifier_block
*nb
)
2000 struct clk_notifier
*cn
;
2008 /* search the list of notifiers for this clk */
2009 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2013 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2014 if (cn
->clk
!= clk
) {
2015 cn
= kzalloc(sizeof(struct clk_notifier
), GFP_KERNEL
);
2020 srcu_init_notifier_head(&cn
->notifier_head
);
2022 list_add(&cn
->node
, &clk_notifier_list
);
2025 ret
= srcu_notifier_chain_register(&cn
->notifier_head
, nb
);
2027 clk
->notifier_count
++;
2030 clk_prepare_unlock();
2034 EXPORT_SYMBOL_GPL(clk_notifier_register
);
2037 * clk_notifier_unregister - remove a clk rate change notifier
2038 * @clk: struct clk *
2039 * @nb: struct notifier_block * with callback info
2041 * Request no further notification for changes to 'clk' and frees memory
2042 * allocated in clk_notifier_register.
2044 * Returns -EINVAL if called with null arguments; otherwise, passes
2045 * along the return value of srcu_notifier_chain_unregister().
2047 int clk_notifier_unregister(struct clk
*clk
, struct notifier_block
*nb
)
2049 struct clk_notifier
*cn
= NULL
;
2057 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2061 if (cn
->clk
== clk
) {
2062 ret
= srcu_notifier_chain_unregister(&cn
->notifier_head
, nb
);
2064 clk
->notifier_count
--;
2066 /* XXX the notifier code should handle this better */
2067 if (!cn
->notifier_head
.head
) {
2068 srcu_cleanup_notifier_head(&cn
->notifier_head
);
2069 list_del(&cn
->node
);
2077 clk_prepare_unlock();
2081 EXPORT_SYMBOL_GPL(clk_notifier_unregister
);
2085 * struct of_clk_provider - Clock provider registration structure
2086 * @link: Entry in global list of clock providers
2087 * @node: Pointer to device tree node of clock provider
2088 * @get: Get clock callback. Returns NULL or a struct clk for the
2089 * given clock specifier
2090 * @data: context pointer to be passed into @get callback
2092 struct of_clk_provider
{
2093 struct list_head link
;
2095 struct device_node
*node
;
2096 struct clk
*(*get
)(struct of_phandle_args
*clkspec
, void *data
);
2100 extern struct of_device_id __clk_of_table
[];
2102 static const struct of_device_id __clk_of_table_sentinel
2103 __used
__section(__clk_of_table_end
);
2105 static LIST_HEAD(of_clk_providers
);
2106 static DEFINE_MUTEX(of_clk_lock
);
2108 struct clk
*of_clk_src_simple_get(struct of_phandle_args
*clkspec
,
2113 EXPORT_SYMBOL_GPL(of_clk_src_simple_get
);
2115 struct clk
*of_clk_src_onecell_get(struct of_phandle_args
*clkspec
, void *data
)
2117 struct clk_onecell_data
*clk_data
= data
;
2118 unsigned int idx
= clkspec
->args
[0];
2120 if (idx
>= clk_data
->clk_num
) {
2121 pr_err("%s: invalid clock index %d\n", __func__
, idx
);
2122 return ERR_PTR(-EINVAL
);
2125 return clk_data
->clks
[idx
];
2127 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get
);
2130 * of_clk_add_provider() - Register a clock provider for a node
2131 * @np: Device node pointer associated with clock provider
2132 * @clk_src_get: callback for decoding clock
2133 * @data: context pointer for @clk_src_get callback.
2135 int of_clk_add_provider(struct device_node
*np
,
2136 struct clk
*(*clk_src_get
)(struct of_phandle_args
*clkspec
,
2140 struct of_clk_provider
*cp
;
2142 cp
= kzalloc(sizeof(struct of_clk_provider
), GFP_KERNEL
);
2146 cp
->node
= of_node_get(np
);
2148 cp
->get
= clk_src_get
;
2150 mutex_lock(&of_clk_lock
);
2151 list_add(&cp
->link
, &of_clk_providers
);
2152 mutex_unlock(&of_clk_lock
);
2153 pr_debug("Added clock from %s\n", np
->full_name
);
2157 EXPORT_SYMBOL_GPL(of_clk_add_provider
);
2160 * of_clk_del_provider() - Remove a previously registered clock provider
2161 * @np: Device node pointer associated with clock provider
2163 void of_clk_del_provider(struct device_node
*np
)
2165 struct of_clk_provider
*cp
;
2167 mutex_lock(&of_clk_lock
);
2168 list_for_each_entry(cp
, &of_clk_providers
, link
) {
2169 if (cp
->node
== np
) {
2170 list_del(&cp
->link
);
2171 of_node_put(cp
->node
);
2176 mutex_unlock(&of_clk_lock
);
2178 EXPORT_SYMBOL_GPL(of_clk_del_provider
);
2180 struct clk
*of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2182 struct of_clk_provider
*provider
;
2183 struct clk
*clk
= ERR_PTR(-ENOENT
);
2185 /* Check if we have such a provider in our array */
2186 mutex_lock(&of_clk_lock
);
2187 list_for_each_entry(provider
, &of_clk_providers
, link
) {
2188 if (provider
->node
== clkspec
->np
)
2189 clk
= provider
->get(clkspec
, provider
->data
);
2193 mutex_unlock(&of_clk_lock
);
2198 const char *of_clk_get_parent_name(struct device_node
*np
, int index
)
2200 struct of_phandle_args clkspec
;
2201 const char *clk_name
;
2207 rc
= of_parse_phandle_with_args(np
, "clocks", "#clock-cells", index
,
2212 if (of_property_read_string_index(clkspec
.np
, "clock-output-names",
2213 clkspec
.args_count
? clkspec
.args
[0] : 0,
2215 clk_name
= clkspec
.np
->name
;
2217 of_node_put(clkspec
.np
);
2220 EXPORT_SYMBOL_GPL(of_clk_get_parent_name
);
2223 * of_clk_init() - Scan and init clock providers from the DT
2224 * @matches: array of compatible values and init functions for providers.
2226 * This function scans the device tree for matching clock providers and
2227 * calls their initialization functions
2229 void __init
of_clk_init(const struct of_device_id
*matches
)
2231 const struct of_device_id
*match
;
2232 struct device_node
*np
;
2235 matches
= __clk_of_table
;
2237 for_each_matching_node_and_match(np
, matches
, &match
) {
2238 of_clk_init_cb_t clk_init_cb
= match
->data
;