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/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>
27 static DEFINE_SPINLOCK(enable_lock
);
28 static DEFINE_MUTEX(prepare_lock
);
30 static struct task_struct
*prepare_owner
;
31 static struct task_struct
*enable_owner
;
33 static int prepare_refcnt
;
34 static int enable_refcnt
;
36 static HLIST_HEAD(clk_root_list
);
37 static HLIST_HEAD(clk_orphan_list
);
38 static LIST_HEAD(clk_notifier_list
);
41 static void clk_prepare_lock(void)
43 if (!mutex_trylock(&prepare_lock
)) {
44 if (prepare_owner
== current
) {
48 mutex_lock(&prepare_lock
);
50 WARN_ON_ONCE(prepare_owner
!= NULL
);
51 WARN_ON_ONCE(prepare_refcnt
!= 0);
52 prepare_owner
= current
;
56 static void clk_prepare_unlock(void)
58 WARN_ON_ONCE(prepare_owner
!= current
);
59 WARN_ON_ONCE(prepare_refcnt
== 0);
64 mutex_unlock(&prepare_lock
);
67 static unsigned long clk_enable_lock(void)
71 if (!spin_trylock_irqsave(&enable_lock
, flags
)) {
72 if (enable_owner
== current
) {
76 spin_lock_irqsave(&enable_lock
, flags
);
78 WARN_ON_ONCE(enable_owner
!= NULL
);
79 WARN_ON_ONCE(enable_refcnt
!= 0);
80 enable_owner
= current
;
85 static void clk_enable_unlock(unsigned long flags
)
87 WARN_ON_ONCE(enable_owner
!= current
);
88 WARN_ON_ONCE(enable_refcnt
== 0);
93 spin_unlock_irqrestore(&enable_lock
, flags
);
96 /*** debugfs support ***/
98 #ifdef CONFIG_DEBUG_FS
99 #include <linux/debugfs.h>
101 static struct dentry
*rootdir
;
102 static int inited
= 0;
104 static struct hlist_head
*all_lists
[] = {
110 static struct hlist_head
*orphan_list
[] = {
115 static void clk_summary_show_one(struct seq_file
*s
, struct clk
*c
, int level
)
120 seq_printf(s
, "%*s%-*s %11d %12d %11lu %10lu\n",
122 30 - level
* 3, c
->name
,
123 c
->enable_count
, c
->prepare_count
, clk_get_rate(c
),
124 clk_get_accuracy(c
));
127 static void clk_summary_show_subtree(struct seq_file
*s
, struct clk
*c
,
135 clk_summary_show_one(s
, c
, level
);
137 hlist_for_each_entry(child
, &c
->children
, child_node
)
138 clk_summary_show_subtree(s
, child
, level
+ 1);
141 static int clk_summary_show(struct seq_file
*s
, void *data
)
144 struct hlist_head
**lists
= (struct hlist_head
**)s
->private;
146 seq_puts(s
, " clock enable_cnt prepare_cnt rate accuracy\n");
147 seq_puts(s
, "--------------------------------------------------------------------------------\n");
151 for (; *lists
; lists
++)
152 hlist_for_each_entry(c
, *lists
, child_node
)
153 clk_summary_show_subtree(s
, c
, 0);
155 clk_prepare_unlock();
161 static int clk_summary_open(struct inode
*inode
, struct file
*file
)
163 return single_open(file
, clk_summary_show
, inode
->i_private
);
166 static const struct file_operations clk_summary_fops
= {
167 .open
= clk_summary_open
,
170 .release
= single_release
,
173 static void clk_dump_one(struct seq_file
*s
, struct clk
*c
, int level
)
178 seq_printf(s
, "\"%s\": { ", c
->name
);
179 seq_printf(s
, "\"enable_count\": %d,", c
->enable_count
);
180 seq_printf(s
, "\"prepare_count\": %d,", c
->prepare_count
);
181 seq_printf(s
, "\"rate\": %lu", clk_get_rate(c
));
182 seq_printf(s
, "\"accuracy\": %lu", clk_get_accuracy(c
));
185 static void clk_dump_subtree(struct seq_file
*s
, struct clk
*c
, int level
)
192 clk_dump_one(s
, c
, level
);
194 hlist_for_each_entry(child
, &c
->children
, child_node
) {
196 clk_dump_subtree(s
, child
, level
+ 1);
202 static int clk_dump(struct seq_file
*s
, void *data
)
205 bool first_node
= true;
206 struct hlist_head
**lists
= (struct hlist_head
**)s
->private;
212 for (; *lists
; lists
++) {
213 hlist_for_each_entry(c
, *lists
, child_node
) {
217 clk_dump_subtree(s
, c
, 0);
221 clk_prepare_unlock();
228 static int clk_dump_open(struct inode
*inode
, struct file
*file
)
230 return single_open(file
, clk_dump
, inode
->i_private
);
233 static const struct file_operations clk_dump_fops
= {
234 .open
= clk_dump_open
,
237 .release
= single_release
,
240 /* caller must hold prepare_lock */
241 static int clk_debug_create_one(struct clk
*clk
, struct dentry
*pdentry
)
246 if (!clk
|| !pdentry
) {
251 d
= debugfs_create_dir(clk
->name
, pdentry
);
257 d
= debugfs_create_u32("clk_rate", S_IRUGO
, clk
->dentry
,
262 d
= debugfs_create_u32("clk_accuracy", S_IRUGO
, clk
->dentry
,
263 (u32
*)&clk
->accuracy
);
267 d
= debugfs_create_x32("clk_flags", S_IRUGO
, clk
->dentry
,
272 d
= debugfs_create_u32("clk_prepare_count", S_IRUGO
, clk
->dentry
,
273 (u32
*)&clk
->prepare_count
);
277 d
= debugfs_create_u32("clk_enable_count", S_IRUGO
, clk
->dentry
,
278 (u32
*)&clk
->enable_count
);
282 d
= debugfs_create_u32("clk_notifier_count", S_IRUGO
, clk
->dentry
,
283 (u32
*)&clk
->notifier_count
);
287 if (clk
->ops
->debug_init
) {
288 ret
= clk
->ops
->debug_init(clk
->hw
, clk
->dentry
);
297 debugfs_remove_recursive(clk
->dentry
);
303 /* caller must hold prepare_lock */
304 static int clk_debug_create_subtree(struct clk
*clk
, struct dentry
*pdentry
)
309 if (!clk
|| !pdentry
)
312 ret
= clk_debug_create_one(clk
, pdentry
);
317 hlist_for_each_entry(child
, &clk
->children
, child_node
)
318 clk_debug_create_subtree(child
, pdentry
);
326 * clk_debug_register - add a clk node to the debugfs clk tree
327 * @clk: the clk being added to the debugfs clk tree
329 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
330 * initialized. Otherwise it bails out early since the debugfs clk tree
331 * will be created lazily by clk_debug_init as part of a late_initcall.
333 * Caller must hold prepare_lock. Only clk_init calls this function (so
334 * far) so this is taken care.
336 static int clk_debug_register(struct clk
*clk
)
343 ret
= clk_debug_create_subtree(clk
, rootdir
);
350 * clk_debug_unregister - remove a clk node from the debugfs clk tree
351 * @clk: the clk being removed from the debugfs clk tree
353 * Dynamically removes a clk and all it's children clk nodes from the
354 * debugfs clk tree if clk->dentry points to debugfs created by
355 * clk_debug_register in __clk_init.
357 * Caller must hold prepare_lock.
359 static void clk_debug_unregister(struct clk
*clk
)
361 debugfs_remove_recursive(clk
->dentry
);
364 struct dentry
*clk_debugfs_add_file(struct clk
*clk
, char *name
, umode_t mode
,
365 void *data
, const struct file_operations
*fops
)
367 struct dentry
*d
= NULL
;
370 d
= debugfs_create_file(name
, mode
, clk
->dentry
, data
, fops
);
374 EXPORT_SYMBOL_GPL(clk_debugfs_add_file
);
377 * clk_debug_init - lazily create the debugfs clk tree visualization
379 * clks are often initialized very early during boot before memory can
380 * be dynamically allocated and well before debugfs is setup.
381 * clk_debug_init walks the clk tree hierarchy while holding
382 * prepare_lock and creates the topology as part of a late_initcall,
383 * thus insuring that clks initialized very early will still be
384 * represented in the debugfs clk tree. This function should only be
385 * called once at boot-time, and all other clks added dynamically will
386 * be done so with clk_debug_register.
388 static int __init
clk_debug_init(void)
393 rootdir
= debugfs_create_dir("clk", NULL
);
398 d
= debugfs_create_file("clk_summary", S_IRUGO
, rootdir
, &all_lists
,
403 d
= debugfs_create_file("clk_dump", S_IRUGO
, rootdir
, &all_lists
,
408 d
= debugfs_create_file("clk_orphan_summary", S_IRUGO
, rootdir
,
409 &orphan_list
, &clk_summary_fops
);
413 d
= debugfs_create_file("clk_orphan_dump", S_IRUGO
, rootdir
,
414 &orphan_list
, &clk_dump_fops
);
420 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
421 clk_debug_create_subtree(clk
, rootdir
);
423 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
424 clk_debug_create_subtree(clk
, rootdir
);
428 clk_prepare_unlock();
432 late_initcall(clk_debug_init
);
434 static inline int clk_debug_register(struct clk
*clk
) { return 0; }
435 static inline void clk_debug_reparent(struct clk
*clk
, struct clk
*new_parent
)
438 static inline void clk_debug_unregister(struct clk
*clk
)
443 /* caller must hold prepare_lock */
444 static void clk_unprepare_unused_subtree(struct clk
*clk
)
451 hlist_for_each_entry(child
, &clk
->children
, child_node
)
452 clk_unprepare_unused_subtree(child
);
454 if (clk
->prepare_count
)
457 if (clk
->flags
& CLK_IGNORE_UNUSED
)
460 if (__clk_is_prepared(clk
)) {
461 if (clk
->ops
->unprepare_unused
)
462 clk
->ops
->unprepare_unused(clk
->hw
);
463 else if (clk
->ops
->unprepare
)
464 clk
->ops
->unprepare(clk
->hw
);
468 /* caller must hold prepare_lock */
469 static void clk_disable_unused_subtree(struct clk
*clk
)
477 hlist_for_each_entry(child
, &clk
->children
, child_node
)
478 clk_disable_unused_subtree(child
);
480 flags
= clk_enable_lock();
482 if (clk
->enable_count
)
485 if (clk
->flags
& CLK_IGNORE_UNUSED
)
489 * some gate clocks have special needs during the disable-unused
490 * sequence. call .disable_unused if available, otherwise fall
493 if (__clk_is_enabled(clk
)) {
494 if (clk
->ops
->disable_unused
)
495 clk
->ops
->disable_unused(clk
->hw
);
496 else if (clk
->ops
->disable
)
497 clk
->ops
->disable(clk
->hw
);
501 clk_enable_unlock(flags
);
507 static bool clk_ignore_unused
;
508 static int __init
clk_ignore_unused_setup(char *__unused
)
510 clk_ignore_unused
= true;
513 __setup("clk_ignore_unused", clk_ignore_unused_setup
);
515 static int clk_disable_unused(void)
519 if (clk_ignore_unused
) {
520 pr_warn("clk: Not disabling unused clocks\n");
526 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
527 clk_disable_unused_subtree(clk
);
529 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
530 clk_disable_unused_subtree(clk
);
532 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
533 clk_unprepare_unused_subtree(clk
);
535 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
536 clk_unprepare_unused_subtree(clk
);
538 clk_prepare_unlock();
542 late_initcall_sync(clk_disable_unused
);
544 /*** helper functions ***/
546 const char *__clk_get_name(struct clk
*clk
)
548 return !clk
? NULL
: clk
->name
;
550 EXPORT_SYMBOL_GPL(__clk_get_name
);
552 struct clk_hw
*__clk_get_hw(struct clk
*clk
)
554 return !clk
? NULL
: clk
->hw
;
556 EXPORT_SYMBOL_GPL(__clk_get_hw
);
558 u8
__clk_get_num_parents(struct clk
*clk
)
560 return !clk
? 0 : clk
->num_parents
;
562 EXPORT_SYMBOL_GPL(__clk_get_num_parents
);
564 struct clk
*__clk_get_parent(struct clk
*clk
)
566 return !clk
? NULL
: clk
->parent
;
568 EXPORT_SYMBOL_GPL(__clk_get_parent
);
570 struct clk
*clk_get_parent_by_index(struct clk
*clk
, u8 index
)
572 if (!clk
|| index
>= clk
->num_parents
)
574 else if (!clk
->parents
)
575 return __clk_lookup(clk
->parent_names
[index
]);
576 else if (!clk
->parents
[index
])
577 return clk
->parents
[index
] =
578 __clk_lookup(clk
->parent_names
[index
]);
580 return clk
->parents
[index
];
582 EXPORT_SYMBOL_GPL(clk_get_parent_by_index
);
584 unsigned int __clk_get_enable_count(struct clk
*clk
)
586 return !clk
? 0 : clk
->enable_count
;
589 unsigned int __clk_get_prepare_count(struct clk
*clk
)
591 return !clk
? 0 : clk
->prepare_count
;
594 unsigned long __clk_get_rate(struct clk
*clk
)
605 if (clk
->flags
& CLK_IS_ROOT
)
614 EXPORT_SYMBOL_GPL(__clk_get_rate
);
616 unsigned long __clk_get_accuracy(struct clk
*clk
)
621 return clk
->accuracy
;
624 unsigned long __clk_get_flags(struct clk
*clk
)
626 return !clk
? 0 : clk
->flags
;
628 EXPORT_SYMBOL_GPL(__clk_get_flags
);
630 bool __clk_is_prepared(struct clk
*clk
)
638 * .is_prepared is optional for clocks that can prepare
639 * fall back to software usage counter if it is missing
641 if (!clk
->ops
->is_prepared
) {
642 ret
= clk
->prepare_count
? 1 : 0;
646 ret
= clk
->ops
->is_prepared(clk
->hw
);
651 bool __clk_is_enabled(struct clk
*clk
)
659 * .is_enabled is only mandatory for clocks that gate
660 * fall back to software usage counter if .is_enabled is missing
662 if (!clk
->ops
->is_enabled
) {
663 ret
= clk
->enable_count
? 1 : 0;
667 ret
= clk
->ops
->is_enabled(clk
->hw
);
671 EXPORT_SYMBOL_GPL(__clk_is_enabled
);
673 static struct clk
*__clk_lookup_subtree(const char *name
, struct clk
*clk
)
678 if (!strcmp(clk
->name
, name
))
681 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
682 ret
= __clk_lookup_subtree(name
, child
);
690 struct clk
*__clk_lookup(const char *name
)
692 struct clk
*root_clk
;
698 /* search the 'proper' clk tree first */
699 hlist_for_each_entry(root_clk
, &clk_root_list
, child_node
) {
700 ret
= __clk_lookup_subtree(name
, root_clk
);
705 /* if not found, then search the orphan tree */
706 hlist_for_each_entry(root_clk
, &clk_orphan_list
, child_node
) {
707 ret
= __clk_lookup_subtree(name
, root_clk
);
716 * Helper for finding best parent to provide a given frequency. This can be used
717 * directly as a determine_rate callback (e.g. for a mux), or from a more
718 * complex clock that may combine a mux with other operations.
720 long __clk_mux_determine_rate(struct clk_hw
*hw
, unsigned long rate
,
721 unsigned long *best_parent_rate
,
722 struct clk
**best_parent_p
)
724 struct clk
*clk
= hw
->clk
, *parent
, *best_parent
= NULL
;
726 unsigned long parent_rate
, best
= 0;
728 /* if NO_REPARENT flag set, pass through to current parent */
729 if (clk
->flags
& CLK_SET_RATE_NO_REPARENT
) {
730 parent
= clk
->parent
;
731 if (clk
->flags
& CLK_SET_RATE_PARENT
)
732 best
= __clk_round_rate(parent
, rate
);
734 best
= __clk_get_rate(parent
);
736 best
= __clk_get_rate(clk
);
740 /* find the parent that can provide the fastest rate <= rate */
741 num_parents
= clk
->num_parents
;
742 for (i
= 0; i
< num_parents
; i
++) {
743 parent
= clk_get_parent_by_index(clk
, i
);
746 if (clk
->flags
& CLK_SET_RATE_PARENT
)
747 parent_rate
= __clk_round_rate(parent
, rate
);
749 parent_rate
= __clk_get_rate(parent
);
750 if (parent_rate
<= rate
&& parent_rate
> best
) {
751 best_parent
= parent
;
758 *best_parent_p
= best_parent
;
759 *best_parent_rate
= best
;
763 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate
);
767 void __clk_unprepare(struct clk
*clk
)
772 if (WARN_ON(clk
->prepare_count
== 0))
775 if (--clk
->prepare_count
> 0)
778 WARN_ON(clk
->enable_count
> 0);
780 if (clk
->ops
->unprepare
)
781 clk
->ops
->unprepare(clk
->hw
);
783 __clk_unprepare(clk
->parent
);
787 * clk_unprepare - undo preparation of a clock source
788 * @clk: the clk being unprepared
790 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
791 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
792 * if the operation may sleep. One example is a clk which is accessed over
793 * I2c. In the complex case a clk gate operation may require a fast and a slow
794 * part. It is this reason that clk_unprepare and clk_disable are not mutually
795 * exclusive. In fact clk_disable must be called before clk_unprepare.
797 void clk_unprepare(struct clk
*clk
)
799 if (IS_ERR_OR_NULL(clk
))
803 __clk_unprepare(clk
);
804 clk_prepare_unlock();
806 EXPORT_SYMBOL_GPL(clk_unprepare
);
808 int __clk_prepare(struct clk
*clk
)
815 if (clk
->prepare_count
== 0) {
816 ret
= __clk_prepare(clk
->parent
);
820 if (clk
->ops
->prepare
) {
821 ret
= clk
->ops
->prepare(clk
->hw
);
823 __clk_unprepare(clk
->parent
);
829 clk
->prepare_count
++;
835 * clk_prepare - prepare a clock source
836 * @clk: the clk being prepared
838 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
839 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
840 * operation may sleep. One example is a clk which is accessed over I2c. In
841 * the complex case a clk ungate operation may require a fast and a slow part.
842 * It is this reason that clk_prepare and clk_enable are not mutually
843 * exclusive. In fact clk_prepare must be called before clk_enable.
844 * Returns 0 on success, -EERROR otherwise.
846 int clk_prepare(struct clk
*clk
)
851 ret
= __clk_prepare(clk
);
852 clk_prepare_unlock();
856 EXPORT_SYMBOL_GPL(clk_prepare
);
858 static void __clk_disable(struct clk
*clk
)
863 if (WARN_ON(clk
->enable_count
== 0))
866 if (--clk
->enable_count
> 0)
869 if (clk
->ops
->disable
)
870 clk
->ops
->disable(clk
->hw
);
872 __clk_disable(clk
->parent
);
876 * clk_disable - gate a clock
877 * @clk: the clk being gated
879 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
880 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
881 * clk if the operation is fast and will never sleep. One example is a
882 * SoC-internal clk which is controlled via simple register writes. In the
883 * complex case a clk gate operation may require a fast and a slow part. It is
884 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
885 * In fact clk_disable must be called before clk_unprepare.
887 void clk_disable(struct clk
*clk
)
891 if (IS_ERR_OR_NULL(clk
))
894 flags
= clk_enable_lock();
896 clk_enable_unlock(flags
);
898 EXPORT_SYMBOL_GPL(clk_disable
);
900 static int __clk_enable(struct clk
*clk
)
907 if (WARN_ON(clk
->prepare_count
== 0))
910 if (clk
->enable_count
== 0) {
911 ret
= __clk_enable(clk
->parent
);
916 if (clk
->ops
->enable
) {
917 ret
= clk
->ops
->enable(clk
->hw
);
919 __clk_disable(clk
->parent
);
930 * clk_enable - ungate a clock
931 * @clk: the clk being ungated
933 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
934 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
935 * if the operation will never sleep. One example is a SoC-internal clk which
936 * is controlled via simple register writes. In the complex case a clk ungate
937 * operation may require a fast and a slow part. It is this reason that
938 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
939 * must be called before clk_enable. Returns 0 on success, -EERROR
942 int clk_enable(struct clk
*clk
)
947 flags
= clk_enable_lock();
948 ret
= __clk_enable(clk
);
949 clk_enable_unlock(flags
);
953 EXPORT_SYMBOL_GPL(clk_enable
);
956 * __clk_round_rate - round the given rate for a clk
957 * @clk: round the rate of this clock
958 * @rate: the rate which is to be rounded
960 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
962 unsigned long __clk_round_rate(struct clk
*clk
, unsigned long rate
)
964 unsigned long parent_rate
= 0;
970 parent
= clk
->parent
;
972 parent_rate
= parent
->rate
;
974 if (clk
->ops
->determine_rate
)
975 return clk
->ops
->determine_rate(clk
->hw
, rate
, &parent_rate
,
977 else if (clk
->ops
->round_rate
)
978 return clk
->ops
->round_rate(clk
->hw
, rate
, &parent_rate
);
979 else if (clk
->flags
& CLK_SET_RATE_PARENT
)
980 return __clk_round_rate(clk
->parent
, rate
);
984 EXPORT_SYMBOL_GPL(__clk_round_rate
);
987 * clk_round_rate - round the given rate for a clk
988 * @clk: the clk for which we are rounding a rate
989 * @rate: the rate which is to be rounded
991 * Takes in a rate as input and rounds it to a rate that the clk can actually
992 * use which is then returned. If clk doesn't support round_rate operation
993 * then the parent rate is returned.
995 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
1000 ret
= __clk_round_rate(clk
, rate
);
1001 clk_prepare_unlock();
1005 EXPORT_SYMBOL_GPL(clk_round_rate
);
1008 * __clk_notify - call clk notifier chain
1009 * @clk: struct clk * that is changing rate
1010 * @msg: clk notifier type (see include/linux/clk.h)
1011 * @old_rate: old clk rate
1012 * @new_rate: new clk rate
1014 * Triggers a notifier call chain on the clk rate-change notification
1015 * for 'clk'. Passes a pointer to the struct clk and the previous
1016 * and current rates to the notifier callback. Intended to be called by
1017 * internal clock code only. Returns NOTIFY_DONE from the last driver
1018 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1019 * a driver returns that.
1021 static int __clk_notify(struct clk
*clk
, unsigned long msg
,
1022 unsigned long old_rate
, unsigned long new_rate
)
1024 struct clk_notifier
*cn
;
1025 struct clk_notifier_data cnd
;
1026 int ret
= NOTIFY_DONE
;
1029 cnd
.old_rate
= old_rate
;
1030 cnd
.new_rate
= new_rate
;
1032 list_for_each_entry(cn
, &clk_notifier_list
, node
) {
1033 if (cn
->clk
== clk
) {
1034 ret
= srcu_notifier_call_chain(&cn
->notifier_head
, msg
,
1044 * __clk_recalc_accuracies
1045 * @clk: first clk in the subtree
1047 * Walks the subtree of clks starting with clk and recalculates accuracies as
1048 * it goes. Note that if a clk does not implement the .recalc_accuracy
1049 * callback then it is assumed that the clock will take on the accuracy of it's
1052 * Caller must hold prepare_lock.
1054 static void __clk_recalc_accuracies(struct clk
*clk
)
1056 unsigned long parent_accuracy
= 0;
1060 parent_accuracy
= clk
->parent
->accuracy
;
1062 if (clk
->ops
->recalc_accuracy
)
1063 clk
->accuracy
= clk
->ops
->recalc_accuracy(clk
->hw
,
1066 clk
->accuracy
= parent_accuracy
;
1068 hlist_for_each_entry(child
, &clk
->children
, child_node
)
1069 __clk_recalc_accuracies(child
);
1073 * clk_get_accuracy - return the accuracy of clk
1074 * @clk: the clk whose accuracy is being returned
1076 * Simply returns the cached accuracy of the clk, unless
1077 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1079 * If clk is NULL then returns 0.
1081 long clk_get_accuracy(struct clk
*clk
)
1083 unsigned long accuracy
;
1086 if (clk
&& (clk
->flags
& CLK_GET_ACCURACY_NOCACHE
))
1087 __clk_recalc_accuracies(clk
);
1089 accuracy
= __clk_get_accuracy(clk
);
1090 clk_prepare_unlock();
1094 EXPORT_SYMBOL_GPL(clk_get_accuracy
);
1096 static unsigned long clk_recalc(struct clk
*clk
, unsigned long parent_rate
)
1098 if (clk
->ops
->recalc_rate
)
1099 return clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
1104 * __clk_recalc_rates
1105 * @clk: first clk in the subtree
1106 * @msg: notification type (see include/linux/clk.h)
1108 * Walks the subtree of clks starting with clk and recalculates rates as it
1109 * goes. Note that if a clk does not implement the .recalc_rate callback then
1110 * it is assumed that the clock will take on the rate of its parent.
1112 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1115 * Caller must hold prepare_lock.
1117 static void __clk_recalc_rates(struct clk
*clk
, unsigned long msg
)
1119 unsigned long old_rate
;
1120 unsigned long parent_rate
= 0;
1123 old_rate
= clk
->rate
;
1126 parent_rate
= clk
->parent
->rate
;
1128 clk
->rate
= clk_recalc(clk
, parent_rate
);
1131 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1132 * & ABORT_RATE_CHANGE notifiers
1134 if (clk
->notifier_count
&& msg
)
1135 __clk_notify(clk
, msg
, old_rate
, clk
->rate
);
1137 hlist_for_each_entry(child
, &clk
->children
, child_node
)
1138 __clk_recalc_rates(child
, msg
);
1142 * clk_get_rate - return the rate of clk
1143 * @clk: the clk whose rate is being returned
1145 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1146 * is set, which means a recalc_rate will be issued.
1147 * If clk is NULL then returns 0.
1149 unsigned long clk_get_rate(struct clk
*clk
)
1155 if (clk
&& (clk
->flags
& CLK_GET_RATE_NOCACHE
))
1156 __clk_recalc_rates(clk
, 0);
1158 rate
= __clk_get_rate(clk
);
1159 clk_prepare_unlock();
1163 EXPORT_SYMBOL_GPL(clk_get_rate
);
1165 static int clk_fetch_parent_index(struct clk
*clk
, struct clk
*parent
)
1169 if (!clk
->parents
) {
1170 clk
->parents
= kcalloc(clk
->num_parents
,
1171 sizeof(struct clk
*), GFP_KERNEL
);
1177 * find index of new parent clock using cached parent ptrs,
1178 * or if not yet cached, use string name comparison and cache
1179 * them now to avoid future calls to __clk_lookup.
1181 for (i
= 0; i
< clk
->num_parents
; i
++) {
1182 if (clk
->parents
[i
] == parent
)
1185 if (clk
->parents
[i
])
1188 if (!strcmp(clk
->parent_names
[i
], parent
->name
)) {
1189 clk
->parents
[i
] = __clk_lookup(parent
->name
);
1197 static void clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1199 hlist_del(&clk
->child_node
);
1202 /* avoid duplicate POST_RATE_CHANGE notifications */
1203 if (new_parent
->new_child
== clk
)
1204 new_parent
->new_child
= NULL
;
1206 hlist_add_head(&clk
->child_node
, &new_parent
->children
);
1208 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1211 clk
->parent
= new_parent
;
1214 static struct clk
*__clk_set_parent_before(struct clk
*clk
, struct clk
*parent
)
1216 unsigned long flags
;
1217 struct clk
*old_parent
= clk
->parent
;
1220 * Migrate prepare state between parents and prevent race with
1223 * If the clock is not prepared, then a race with
1224 * clk_enable/disable() is impossible since we already have the
1225 * prepare lock (future calls to clk_enable() need to be preceded by
1228 * If the clock is prepared, migrate the prepared state to the new
1229 * parent and also protect against a race with clk_enable() by
1230 * forcing the clock and the new parent on. This ensures that all
1231 * future calls to clk_enable() are practically NOPs with respect to
1232 * hardware and software states.
1234 * See also: Comment for clk_set_parent() below.
1236 if (clk
->prepare_count
) {
1237 __clk_prepare(parent
);
1242 /* update the clk tree topology */
1243 flags
= clk_enable_lock();
1244 clk_reparent(clk
, parent
);
1245 clk_enable_unlock(flags
);
1250 static void __clk_set_parent_after(struct clk
*clk
, struct clk
*parent
,
1251 struct clk
*old_parent
)
1254 * Finish the migration of prepare state and undo the changes done
1255 * for preventing a race with clk_enable().
1257 if (clk
->prepare_count
) {
1259 clk_disable(old_parent
);
1260 __clk_unprepare(old_parent
);
1264 static int __clk_set_parent(struct clk
*clk
, struct clk
*parent
, u8 p_index
)
1266 unsigned long flags
;
1268 struct clk
*old_parent
;
1270 old_parent
= __clk_set_parent_before(clk
, parent
);
1272 /* change clock input source */
1273 if (parent
&& clk
->ops
->set_parent
)
1274 ret
= clk
->ops
->set_parent(clk
->hw
, p_index
);
1277 flags
= clk_enable_lock();
1278 clk_reparent(clk
, old_parent
);
1279 clk_enable_unlock(flags
);
1281 if (clk
->prepare_count
) {
1283 clk_disable(parent
);
1284 __clk_unprepare(parent
);
1289 __clk_set_parent_after(clk
, parent
, old_parent
);
1295 * __clk_speculate_rates
1296 * @clk: first clk in the subtree
1297 * @parent_rate: the "future" rate of clk's parent
1299 * Walks the subtree of clks starting with clk, speculating rates as it
1300 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1302 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1303 * pre-rate change notifications and returns early if no clks in the
1304 * subtree have subscribed to the notifications. Note that if a clk does not
1305 * implement the .recalc_rate callback then it is assumed that the clock will
1306 * take on the rate of its parent.
1308 * Caller must hold prepare_lock.
1310 static int __clk_speculate_rates(struct clk
*clk
, unsigned long parent_rate
)
1313 unsigned long new_rate
;
1314 int ret
= NOTIFY_DONE
;
1316 new_rate
= clk_recalc(clk
, parent_rate
);
1318 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1319 if (clk
->notifier_count
)
1320 ret
= __clk_notify(clk
, PRE_RATE_CHANGE
, clk
->rate
, new_rate
);
1322 if (ret
& NOTIFY_STOP_MASK
) {
1323 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1324 __func__
, clk
->name
, ret
);
1328 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1329 ret
= __clk_speculate_rates(child
, new_rate
);
1330 if (ret
& NOTIFY_STOP_MASK
)
1338 static void clk_calc_subtree(struct clk
*clk
, unsigned long new_rate
,
1339 struct clk
*new_parent
, u8 p_index
)
1343 clk
->new_rate
= new_rate
;
1344 clk
->new_parent
= new_parent
;
1345 clk
->new_parent_index
= p_index
;
1346 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1347 clk
->new_child
= NULL
;
1348 if (new_parent
&& new_parent
!= clk
->parent
)
1349 new_parent
->new_child
= clk
;
1351 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1352 child
->new_rate
= clk_recalc(child
, new_rate
);
1353 clk_calc_subtree(child
, child
->new_rate
, NULL
, 0);
1358 * calculate the new rates returning the topmost clock that has to be
1361 static struct clk
*clk_calc_new_rates(struct clk
*clk
, unsigned long rate
)
1363 struct clk
*top
= clk
;
1364 struct clk
*old_parent
, *parent
;
1365 unsigned long best_parent_rate
= 0;
1366 unsigned long new_rate
;
1370 if (IS_ERR_OR_NULL(clk
))
1373 /* save parent rate, if it exists */
1374 parent
= old_parent
= clk
->parent
;
1376 best_parent_rate
= parent
->rate
;
1378 /* find the closest rate and parent clk/rate */
1379 if (clk
->ops
->determine_rate
) {
1380 new_rate
= clk
->ops
->determine_rate(clk
->hw
, rate
,
1383 } else if (clk
->ops
->round_rate
) {
1384 new_rate
= clk
->ops
->round_rate(clk
->hw
, rate
,
1386 } else if (!parent
|| !(clk
->flags
& CLK_SET_RATE_PARENT
)) {
1387 /* pass-through clock without adjustable parent */
1388 clk
->new_rate
= clk
->rate
;
1391 /* pass-through clock with adjustable parent */
1392 top
= clk_calc_new_rates(parent
, rate
);
1393 new_rate
= parent
->new_rate
;
1397 /* some clocks must be gated to change parent */
1398 if (parent
!= old_parent
&&
1399 (clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1400 pr_debug("%s: %s not gated but wants to reparent\n",
1401 __func__
, clk
->name
);
1405 /* try finding the new parent index */
1407 p_index
= clk_fetch_parent_index(clk
, parent
);
1409 pr_debug("%s: clk %s can not be parent of clk %s\n",
1410 __func__
, parent
->name
, clk
->name
);
1415 if ((clk
->flags
& CLK_SET_RATE_PARENT
) && parent
&&
1416 best_parent_rate
!= parent
->rate
)
1417 top
= clk_calc_new_rates(parent
, best_parent_rate
);
1420 clk_calc_subtree(clk
, new_rate
, parent
, p_index
);
1426 * Notify about rate changes in a subtree. Always walk down the whole tree
1427 * so that in case of an error we can walk down the whole tree again and
1430 static struct clk
*clk_propagate_rate_change(struct clk
*clk
, unsigned long event
)
1432 struct clk
*child
, *tmp_clk
, *fail_clk
= NULL
;
1433 int ret
= NOTIFY_DONE
;
1435 if (clk
->rate
== clk
->new_rate
)
1438 if (clk
->notifier_count
) {
1439 ret
= __clk_notify(clk
, event
, clk
->rate
, clk
->new_rate
);
1440 if (ret
& NOTIFY_STOP_MASK
)
1444 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1445 /* Skip children who will be reparented to another clock */
1446 if (child
->new_parent
&& child
->new_parent
!= clk
)
1448 tmp_clk
= clk_propagate_rate_change(child
, event
);
1453 /* handle the new child who might not be in clk->children yet */
1454 if (clk
->new_child
) {
1455 tmp_clk
= clk_propagate_rate_change(clk
->new_child
, event
);
1464 * walk down a subtree and set the new rates notifying the rate
1467 static void clk_change_rate(struct clk
*clk
)
1470 unsigned long old_rate
;
1471 unsigned long best_parent_rate
= 0;
1472 bool skip_set_rate
= false;
1473 struct clk
*old_parent
;
1475 old_rate
= clk
->rate
;
1477 if (clk
->new_parent
)
1478 best_parent_rate
= clk
->new_parent
->rate
;
1479 else if (clk
->parent
)
1480 best_parent_rate
= clk
->parent
->rate
;
1482 if (clk
->new_parent
&& clk
->new_parent
!= clk
->parent
) {
1483 old_parent
= __clk_set_parent_before(clk
, clk
->new_parent
);
1485 if (clk
->ops
->set_rate_and_parent
) {
1486 skip_set_rate
= true;
1487 clk
->ops
->set_rate_and_parent(clk
->hw
, clk
->new_rate
,
1489 clk
->new_parent_index
);
1490 } else if (clk
->ops
->set_parent
) {
1491 clk
->ops
->set_parent(clk
->hw
, clk
->new_parent_index
);
1494 __clk_set_parent_after(clk
, clk
->new_parent
, old_parent
);
1497 if (!skip_set_rate
&& clk
->ops
->set_rate
)
1498 clk
->ops
->set_rate(clk
->hw
, clk
->new_rate
, best_parent_rate
);
1500 clk
->rate
= clk_recalc(clk
, best_parent_rate
);
1502 if (clk
->notifier_count
&& old_rate
!= clk
->rate
)
1503 __clk_notify(clk
, POST_RATE_CHANGE
, old_rate
, clk
->rate
);
1505 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1506 /* Skip children who will be reparented to another clock */
1507 if (child
->new_parent
&& child
->new_parent
!= clk
)
1509 clk_change_rate(child
);
1512 /* handle the new child who might not be in clk->children yet */
1514 clk_change_rate(clk
->new_child
);
1518 * clk_set_rate - specify a new rate for clk
1519 * @clk: the clk whose rate is being changed
1520 * @rate: the new rate for clk
1522 * In the simplest case clk_set_rate will only adjust the rate of clk.
1524 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1525 * propagate up to clk's parent; whether or not this happens depends on the
1526 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1527 * after calling .round_rate then upstream parent propagation is ignored. If
1528 * *parent_rate comes back with a new rate for clk's parent then we propagate
1529 * up to clk's parent and set its rate. Upward propagation will continue
1530 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1531 * .round_rate stops requesting changes to clk's parent_rate.
1533 * Rate changes are accomplished via tree traversal that also recalculates the
1534 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1536 * Returns 0 on success, -EERROR otherwise.
1538 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
1540 struct clk
*top
, *fail_clk
;
1546 /* prevent racing with updates to the clock topology */
1549 /* bail early if nothing to do */
1550 if (rate
== clk_get_rate(clk
))
1553 if ((clk
->flags
& CLK_SET_RATE_GATE
) && clk
->prepare_count
) {
1558 /* calculate new rates and get the topmost changed clock */
1559 top
= clk_calc_new_rates(clk
, rate
);
1565 /* notify that we are about to change rates */
1566 fail_clk
= clk_propagate_rate_change(top
, PRE_RATE_CHANGE
);
1568 pr_debug("%s: failed to set %s rate\n", __func__
,
1570 clk_propagate_rate_change(top
, ABORT_RATE_CHANGE
);
1575 /* change the rates */
1576 clk_change_rate(top
);
1579 clk_prepare_unlock();
1583 EXPORT_SYMBOL_GPL(clk_set_rate
);
1586 * clk_get_parent - return the parent of a clk
1587 * @clk: the clk whose parent gets returned
1589 * Simply returns clk->parent. Returns NULL if clk is NULL.
1591 struct clk
*clk_get_parent(struct clk
*clk
)
1596 parent
= __clk_get_parent(clk
);
1597 clk_prepare_unlock();
1601 EXPORT_SYMBOL_GPL(clk_get_parent
);
1604 * .get_parent is mandatory for clocks with multiple possible parents. It is
1605 * optional for single-parent clocks. Always call .get_parent if it is
1606 * available and WARN if it is missing for multi-parent clocks.
1608 * For single-parent clocks without .get_parent, first check to see if the
1609 * .parents array exists, and if so use it to avoid an expensive tree
1610 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1612 static struct clk
*__clk_init_parent(struct clk
*clk
)
1614 struct clk
*ret
= NULL
;
1617 /* handle the trivial cases */
1619 if (!clk
->num_parents
)
1622 if (clk
->num_parents
== 1) {
1623 if (IS_ERR_OR_NULL(clk
->parent
))
1624 ret
= clk
->parent
= __clk_lookup(clk
->parent_names
[0]);
1629 if (!clk
->ops
->get_parent
) {
1630 WARN(!clk
->ops
->get_parent
,
1631 "%s: multi-parent clocks must implement .get_parent\n",
1637 * Do our best to cache parent clocks in clk->parents. This prevents
1638 * unnecessary and expensive calls to __clk_lookup. We don't set
1639 * clk->parent here; that is done by the calling function
1642 index
= clk
->ops
->get_parent(clk
->hw
);
1646 kcalloc(clk
->num_parents
, sizeof(struct clk
*),
1649 ret
= clk_get_parent_by_index(clk
, index
);
1655 void __clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1657 clk_reparent(clk
, new_parent
);
1658 __clk_recalc_accuracies(clk
);
1659 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1663 * clk_set_parent - switch the parent of a mux clk
1664 * @clk: the mux clk whose input we are switching
1665 * @parent: the new input to clk
1667 * Re-parent clk to use parent as its new input source. If clk is in
1668 * prepared state, the clk will get enabled for the duration of this call. If
1669 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1670 * that, the reparenting is glitchy in hardware, etc), use the
1671 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1673 * After successfully changing clk's parent clk_set_parent will update the
1674 * clk topology, sysfs topology and propagate rate recalculation via
1675 * __clk_recalc_rates.
1677 * Returns 0 on success, -EERROR otherwise.
1679 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
1683 unsigned long p_rate
= 0;
1688 /* verify ops for for multi-parent clks */
1689 if ((clk
->num_parents
> 1) && (!clk
->ops
->set_parent
))
1692 /* prevent racing with updates to the clock topology */
1695 if (clk
->parent
== parent
)
1698 /* check that we are allowed to re-parent if the clock is in use */
1699 if ((clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1704 /* try finding the new parent index */
1706 p_index
= clk_fetch_parent_index(clk
, parent
);
1707 p_rate
= parent
->rate
;
1709 pr_debug("%s: clk %s can not be parent of clk %s\n",
1710 __func__
, parent
->name
, clk
->name
);
1716 /* propagate PRE_RATE_CHANGE notifications */
1717 ret
= __clk_speculate_rates(clk
, p_rate
);
1719 /* abort if a driver objects */
1720 if (ret
& NOTIFY_STOP_MASK
)
1723 /* do the re-parent */
1724 ret
= __clk_set_parent(clk
, parent
, p_index
);
1726 /* propagate rate an accuracy recalculation accordingly */
1728 __clk_recalc_rates(clk
, ABORT_RATE_CHANGE
);
1730 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1731 __clk_recalc_accuracies(clk
);
1735 clk_prepare_unlock();
1739 EXPORT_SYMBOL_GPL(clk_set_parent
);
1742 * __clk_init - initialize the data structures in a struct clk
1743 * @dev: device initializing this clk, placeholder for now
1744 * @clk: clk being initialized
1746 * Initializes the lists in struct clk, queries the hardware for the
1747 * parent and rate and sets them both.
1749 int __clk_init(struct device
*dev
, struct clk
*clk
)
1753 struct hlist_node
*tmp2
;
1760 /* check to see if a clock with this name is already registered */
1761 if (__clk_lookup(clk
->name
)) {
1762 pr_debug("%s: clk %s already initialized\n",
1763 __func__
, clk
->name
);
1768 /* check that clk_ops are sane. See Documentation/clk.txt */
1769 if (clk
->ops
->set_rate
&&
1770 !((clk
->ops
->round_rate
|| clk
->ops
->determine_rate
) &&
1771 clk
->ops
->recalc_rate
)) {
1772 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1773 __func__
, clk
->name
);
1778 if (clk
->ops
->set_parent
&& !clk
->ops
->get_parent
) {
1779 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1780 __func__
, clk
->name
);
1785 if (clk
->ops
->set_rate_and_parent
&&
1786 !(clk
->ops
->set_parent
&& clk
->ops
->set_rate
)) {
1787 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
1788 __func__
, clk
->name
);
1793 /* throw a WARN if any entries in parent_names are NULL */
1794 for (i
= 0; i
< clk
->num_parents
; i
++)
1795 WARN(!clk
->parent_names
[i
],
1796 "%s: invalid NULL in %s's .parent_names\n",
1797 __func__
, clk
->name
);
1800 * Allocate an array of struct clk *'s to avoid unnecessary string
1801 * look-ups of clk's possible parents. This can fail for clocks passed
1802 * in to clk_init during early boot; thus any access to clk->parents[]
1803 * must always check for a NULL pointer and try to populate it if
1806 * If clk->parents is not NULL we skip this entire block. This allows
1807 * for clock drivers to statically initialize clk->parents.
1809 if (clk
->num_parents
> 1 && !clk
->parents
) {
1810 clk
->parents
= kcalloc(clk
->num_parents
, sizeof(struct clk
*),
1813 * __clk_lookup returns NULL for parents that have not been
1814 * clk_init'd; thus any access to clk->parents[] must check
1815 * for a NULL pointer. We can always perform lazy lookups for
1816 * missing parents later on.
1819 for (i
= 0; i
< clk
->num_parents
; i
++)
1821 __clk_lookup(clk
->parent_names
[i
]);
1824 clk
->parent
= __clk_init_parent(clk
);
1827 * Populate clk->parent if parent has already been __clk_init'd. If
1828 * parent has not yet been __clk_init'd then place clk in the orphan
1829 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1832 * Every time a new clk is clk_init'd then we walk the list of orphan
1833 * clocks and re-parent any that are children of the clock currently
1837 hlist_add_head(&clk
->child_node
,
1838 &clk
->parent
->children
);
1839 else if (clk
->flags
& CLK_IS_ROOT
)
1840 hlist_add_head(&clk
->child_node
, &clk_root_list
);
1842 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1845 * Set clk's accuracy. The preferred method is to use
1846 * .recalc_accuracy. For simple clocks and lazy developers the default
1847 * fallback is to use the parent's accuracy. If a clock doesn't have a
1848 * parent (or is orphaned) then accuracy is set to zero (perfect
1851 if (clk
->ops
->recalc_accuracy
)
1852 clk
->accuracy
= clk
->ops
->recalc_accuracy(clk
->hw
,
1853 __clk_get_accuracy(clk
->parent
));
1854 else if (clk
->parent
)
1855 clk
->accuracy
= clk
->parent
->accuracy
;
1860 * Set clk's rate. The preferred method is to use .recalc_rate. For
1861 * simple clocks and lazy developers the default fallback is to use the
1862 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1863 * then rate is set to zero.
1865 if (clk
->ops
->recalc_rate
)
1866 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
,
1867 __clk_get_rate(clk
->parent
));
1868 else if (clk
->parent
)
1869 clk
->rate
= clk
->parent
->rate
;
1873 clk_debug_register(clk
);
1875 * walk the list of orphan clocks and reparent any that are children of
1878 hlist_for_each_entry_safe(orphan
, tmp2
, &clk_orphan_list
, child_node
) {
1879 if (orphan
->num_parents
&& orphan
->ops
->get_parent
) {
1880 i
= orphan
->ops
->get_parent(orphan
->hw
);
1881 if (!strcmp(clk
->name
, orphan
->parent_names
[i
]))
1882 __clk_reparent(orphan
, clk
);
1886 for (i
= 0; i
< orphan
->num_parents
; i
++)
1887 if (!strcmp(clk
->name
, orphan
->parent_names
[i
])) {
1888 __clk_reparent(orphan
, clk
);
1894 * optional platform-specific magic
1896 * The .init callback is not used by any of the basic clock types, but
1897 * exists for weird hardware that must perform initialization magic.
1898 * Please consider other ways of solving initialization problems before
1899 * using this callback, as its use is discouraged.
1902 clk
->ops
->init(clk
->hw
);
1904 kref_init(&clk
->ref
);
1906 clk_prepare_unlock();
1912 * __clk_register - register a clock and return a cookie.
1914 * Same as clk_register, except that the .clk field inside hw shall point to a
1915 * preallocated (generally statically allocated) struct clk. None of the fields
1916 * of the struct clk need to be initialized.
1918 * The data pointed to by .init and .clk field shall NOT be marked as init
1921 * __clk_register is only exposed via clk-private.h and is intended for use with
1922 * very large numbers of clocks that need to be statically initialized. It is
1923 * a layering violation to include clk-private.h from any code which implements
1924 * a clock's .ops; as such any statically initialized clock data MUST be in a
1925 * separate C file from the logic that implements its operations. Returns 0
1926 * on success, otherwise an error code.
1928 struct clk
*__clk_register(struct device
*dev
, struct clk_hw
*hw
)
1934 clk
->name
= hw
->init
->name
;
1935 clk
->ops
= hw
->init
->ops
;
1937 clk
->flags
= hw
->init
->flags
;
1938 clk
->parent_names
= hw
->init
->parent_names
;
1939 clk
->num_parents
= hw
->init
->num_parents
;
1940 if (dev
&& dev
->driver
)
1941 clk
->owner
= dev
->driver
->owner
;
1945 ret
= __clk_init(dev
, clk
);
1947 return ERR_PTR(ret
);
1951 EXPORT_SYMBOL_GPL(__clk_register
);
1954 * clk_register - allocate a new clock, register it and return an opaque cookie
1955 * @dev: device that is registering this clock
1956 * @hw: link to hardware-specific clock data
1958 * clk_register is the primary interface for populating the clock tree with new
1959 * clock nodes. It returns a pointer to the newly allocated struct clk which
1960 * cannot be dereferenced by driver code but may be used in conjuction with the
1961 * rest of the clock API. In the event of an error clk_register will return an
1962 * error code; drivers must test for an error code after calling clk_register.
1964 struct clk
*clk_register(struct device
*dev
, struct clk_hw
*hw
)
1969 clk
= kzalloc(sizeof(*clk
), GFP_KERNEL
);
1971 pr_err("%s: could not allocate clk\n", __func__
);
1976 clk
->name
= kstrdup(hw
->init
->name
, GFP_KERNEL
);
1978 pr_err("%s: could not allocate clk->name\n", __func__
);
1982 clk
->ops
= hw
->init
->ops
;
1983 if (dev
&& dev
->driver
)
1984 clk
->owner
= dev
->driver
->owner
;
1986 clk
->flags
= hw
->init
->flags
;
1987 clk
->num_parents
= hw
->init
->num_parents
;
1990 /* allocate local copy in case parent_names is __initdata */
1991 clk
->parent_names
= kcalloc(clk
->num_parents
, sizeof(char *),
1994 if (!clk
->parent_names
) {
1995 pr_err("%s: could not allocate clk->parent_names\n", __func__
);
1997 goto fail_parent_names
;
2001 /* copy each string name in case parent_names is __initdata */
2002 for (i
= 0; i
< clk
->num_parents
; i
++) {
2003 clk
->parent_names
[i
] = kstrdup(hw
->init
->parent_names
[i
],
2005 if (!clk
->parent_names
[i
]) {
2006 pr_err("%s: could not copy parent_names\n", __func__
);
2008 goto fail_parent_names_copy
;
2012 ret
= __clk_init(dev
, clk
);
2016 fail_parent_names_copy
:
2018 kfree(clk
->parent_names
[i
]);
2019 kfree(clk
->parent_names
);
2025 return ERR_PTR(ret
);
2027 EXPORT_SYMBOL_GPL(clk_register
);
2030 * Free memory allocated for a clock.
2031 * Caller must hold prepare_lock.
2033 static void __clk_release(struct kref
*ref
)
2035 struct clk
*clk
= container_of(ref
, struct clk
, ref
);
2036 int i
= clk
->num_parents
;
2038 kfree(clk
->parents
);
2040 kfree(clk
->parent_names
[i
]);
2042 kfree(clk
->parent_names
);
2048 * Empty clk_ops for unregistered clocks. These are used temporarily
2049 * after clk_unregister() was called on a clock and until last clock
2050 * consumer calls clk_put() and the struct clk object is freed.
2052 static int clk_nodrv_prepare_enable(struct clk_hw
*hw
)
2057 static void clk_nodrv_disable_unprepare(struct clk_hw
*hw
)
2062 static int clk_nodrv_set_rate(struct clk_hw
*hw
, unsigned long rate
,
2063 unsigned long parent_rate
)
2068 static int clk_nodrv_set_parent(struct clk_hw
*hw
, u8 index
)
2073 static const struct clk_ops clk_nodrv_ops
= {
2074 .enable
= clk_nodrv_prepare_enable
,
2075 .disable
= clk_nodrv_disable_unprepare
,
2076 .prepare
= clk_nodrv_prepare_enable
,
2077 .unprepare
= clk_nodrv_disable_unprepare
,
2078 .set_rate
= clk_nodrv_set_rate
,
2079 .set_parent
= clk_nodrv_set_parent
,
2083 * clk_unregister - unregister a currently registered clock
2084 * @clk: clock to unregister
2086 void clk_unregister(struct clk
*clk
)
2088 unsigned long flags
;
2090 if (!clk
|| WARN_ON_ONCE(IS_ERR(clk
)))
2095 if (clk
->ops
== &clk_nodrv_ops
) {
2096 pr_err("%s: unregistered clock: %s\n", __func__
, clk
->name
);
2100 * Assign empty clock ops for consumers that might still hold
2101 * a reference to this clock.
2103 flags
= clk_enable_lock();
2104 clk
->ops
= &clk_nodrv_ops
;
2105 clk_enable_unlock(flags
);
2107 if (!hlist_empty(&clk
->children
)) {
2109 struct hlist_node
*t
;
2111 /* Reparent all children to the orphan list. */
2112 hlist_for_each_entry_safe(child
, t
, &clk
->children
, child_node
)
2113 clk_set_parent(child
, NULL
);
2116 clk_debug_unregister(clk
);
2118 hlist_del_init(&clk
->child_node
);
2120 if (clk
->prepare_count
)
2121 pr_warn("%s: unregistering prepared clock: %s\n",
2122 __func__
, clk
->name
);
2124 kref_put(&clk
->ref
, __clk_release
);
2126 clk_prepare_unlock();
2128 EXPORT_SYMBOL_GPL(clk_unregister
);
2130 static void devm_clk_release(struct device
*dev
, void *res
)
2132 clk_unregister(*(struct clk
**)res
);
2136 * devm_clk_register - resource managed clk_register()
2137 * @dev: device that is registering this clock
2138 * @hw: link to hardware-specific clock data
2140 * Managed clk_register(). Clocks returned from this function are
2141 * automatically clk_unregister()ed on driver detach. See clk_register() for
2144 struct clk
*devm_clk_register(struct device
*dev
, struct clk_hw
*hw
)
2149 clkp
= devres_alloc(devm_clk_release
, sizeof(*clkp
), GFP_KERNEL
);
2151 return ERR_PTR(-ENOMEM
);
2153 clk
= clk_register(dev
, hw
);
2156 devres_add(dev
, clkp
);
2163 EXPORT_SYMBOL_GPL(devm_clk_register
);
2165 static int devm_clk_match(struct device
*dev
, void *res
, void *data
)
2167 struct clk
*c
= res
;
2174 * devm_clk_unregister - resource managed clk_unregister()
2175 * @clk: clock to unregister
2177 * Deallocate a clock allocated with devm_clk_register(). Normally
2178 * this function will not need to be called and the resource management
2179 * code will ensure that the resource is freed.
2181 void devm_clk_unregister(struct device
*dev
, struct clk
*clk
)
2183 WARN_ON(devres_release(dev
, devm_clk_release
, devm_clk_match
, clk
));
2185 EXPORT_SYMBOL_GPL(devm_clk_unregister
);
2190 int __clk_get(struct clk
*clk
)
2193 if (!try_module_get(clk
->owner
))
2196 kref_get(&clk
->ref
);
2201 void __clk_put(struct clk
*clk
)
2203 if (!clk
|| WARN_ON_ONCE(IS_ERR(clk
)))
2207 kref_put(&clk
->ref
, __clk_release
);
2208 clk_prepare_unlock();
2210 module_put(clk
->owner
);
2213 /*** clk rate change notifiers ***/
2216 * clk_notifier_register - add a clk rate change notifier
2217 * @clk: struct clk * to watch
2218 * @nb: struct notifier_block * with callback info
2220 * Request notification when clk's rate changes. This uses an SRCU
2221 * notifier because we want it to block and notifier unregistrations are
2222 * uncommon. The callbacks associated with the notifier must not
2223 * re-enter into the clk framework by calling any top-level clk APIs;
2224 * this will cause a nested prepare_lock mutex.
2226 * In all notification cases cases (pre, post and abort rate change) the
2227 * original clock rate is passed to the callback via struct
2228 * clk_notifier_data.old_rate and the new frequency is passed via struct
2229 * clk_notifier_data.new_rate.
2231 * clk_notifier_register() must be called from non-atomic context.
2232 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2233 * allocation failure; otherwise, passes along the return value of
2234 * srcu_notifier_chain_register().
2236 int clk_notifier_register(struct clk
*clk
, struct notifier_block
*nb
)
2238 struct clk_notifier
*cn
;
2246 /* search the list of notifiers for this clk */
2247 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2251 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2252 if (cn
->clk
!= clk
) {
2253 cn
= kzalloc(sizeof(struct clk_notifier
), GFP_KERNEL
);
2258 srcu_init_notifier_head(&cn
->notifier_head
);
2260 list_add(&cn
->node
, &clk_notifier_list
);
2263 ret
= srcu_notifier_chain_register(&cn
->notifier_head
, nb
);
2265 clk
->notifier_count
++;
2268 clk_prepare_unlock();
2272 EXPORT_SYMBOL_GPL(clk_notifier_register
);
2275 * clk_notifier_unregister - remove a clk rate change notifier
2276 * @clk: struct clk *
2277 * @nb: struct notifier_block * with callback info
2279 * Request no further notification for changes to 'clk' and frees memory
2280 * allocated in clk_notifier_register.
2282 * Returns -EINVAL if called with null arguments; otherwise, passes
2283 * along the return value of srcu_notifier_chain_unregister().
2285 int clk_notifier_unregister(struct clk
*clk
, struct notifier_block
*nb
)
2287 struct clk_notifier
*cn
= NULL
;
2295 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2299 if (cn
->clk
== clk
) {
2300 ret
= srcu_notifier_chain_unregister(&cn
->notifier_head
, nb
);
2302 clk
->notifier_count
--;
2304 /* XXX the notifier code should handle this better */
2305 if (!cn
->notifier_head
.head
) {
2306 srcu_cleanup_notifier_head(&cn
->notifier_head
);
2307 list_del(&cn
->node
);
2315 clk_prepare_unlock();
2319 EXPORT_SYMBOL_GPL(clk_notifier_unregister
);
2323 * struct of_clk_provider - Clock provider registration structure
2324 * @link: Entry in global list of clock providers
2325 * @node: Pointer to device tree node of clock provider
2326 * @get: Get clock callback. Returns NULL or a struct clk for the
2327 * given clock specifier
2328 * @data: context pointer to be passed into @get callback
2330 struct of_clk_provider
{
2331 struct list_head link
;
2333 struct device_node
*node
;
2334 struct clk
*(*get
)(struct of_phandle_args
*clkspec
, void *data
);
2338 static const struct of_device_id __clk_of_table_sentinel
2339 __used
__section(__clk_of_table_end
);
2341 static LIST_HEAD(of_clk_providers
);
2342 static DEFINE_MUTEX(of_clk_mutex
);
2344 /* of_clk_provider list locking helpers */
2345 void of_clk_lock(void)
2347 mutex_lock(&of_clk_mutex
);
2350 void of_clk_unlock(void)
2352 mutex_unlock(&of_clk_mutex
);
2355 struct clk
*of_clk_src_simple_get(struct of_phandle_args
*clkspec
,
2360 EXPORT_SYMBOL_GPL(of_clk_src_simple_get
);
2362 struct clk
*of_clk_src_onecell_get(struct of_phandle_args
*clkspec
, void *data
)
2364 struct clk_onecell_data
*clk_data
= data
;
2365 unsigned int idx
= clkspec
->args
[0];
2367 if (idx
>= clk_data
->clk_num
) {
2368 pr_err("%s: invalid clock index %d\n", __func__
, idx
);
2369 return ERR_PTR(-EINVAL
);
2372 return clk_data
->clks
[idx
];
2374 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get
);
2377 * of_clk_add_provider() - Register a clock provider for a node
2378 * @np: Device node pointer associated with clock provider
2379 * @clk_src_get: callback for decoding clock
2380 * @data: context pointer for @clk_src_get callback.
2382 int of_clk_add_provider(struct device_node
*np
,
2383 struct clk
*(*clk_src_get
)(struct of_phandle_args
*clkspec
,
2387 struct of_clk_provider
*cp
;
2390 cp
= kzalloc(sizeof(struct of_clk_provider
), GFP_KERNEL
);
2394 cp
->node
= of_node_get(np
);
2396 cp
->get
= clk_src_get
;
2398 mutex_lock(&of_clk_mutex
);
2399 list_add(&cp
->link
, &of_clk_providers
);
2400 mutex_unlock(&of_clk_mutex
);
2401 pr_debug("Added clock from %s\n", np
->full_name
);
2403 ret
= of_clk_set_defaults(np
, true);
2405 of_clk_del_provider(np
);
2409 EXPORT_SYMBOL_GPL(of_clk_add_provider
);
2412 * of_clk_del_provider() - Remove a previously registered clock provider
2413 * @np: Device node pointer associated with clock provider
2415 void of_clk_del_provider(struct device_node
*np
)
2417 struct of_clk_provider
*cp
;
2419 mutex_lock(&of_clk_mutex
);
2420 list_for_each_entry(cp
, &of_clk_providers
, link
) {
2421 if (cp
->node
== np
) {
2422 list_del(&cp
->link
);
2423 of_node_put(cp
->node
);
2428 mutex_unlock(&of_clk_mutex
);
2430 EXPORT_SYMBOL_GPL(of_clk_del_provider
);
2432 struct clk
*__of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2434 struct of_clk_provider
*provider
;
2435 struct clk
*clk
= ERR_PTR(-EPROBE_DEFER
);
2437 /* Check if we have such a provider in our array */
2438 list_for_each_entry(provider
, &of_clk_providers
, link
) {
2439 if (provider
->node
== clkspec
->np
)
2440 clk
= provider
->get(clkspec
, provider
->data
);
2448 struct clk
*of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2452 mutex_lock(&of_clk_mutex
);
2453 clk
= __of_clk_get_from_provider(clkspec
);
2454 mutex_unlock(&of_clk_mutex
);
2459 int of_clk_get_parent_count(struct device_node
*np
)
2461 return of_count_phandle_with_args(np
, "clocks", "#clock-cells");
2463 EXPORT_SYMBOL_GPL(of_clk_get_parent_count
);
2465 const char *of_clk_get_parent_name(struct device_node
*np
, int index
)
2467 struct of_phandle_args clkspec
;
2468 struct property
*prop
;
2469 const char *clk_name
;
2478 rc
= of_parse_phandle_with_args(np
, "clocks", "#clock-cells", index
,
2483 index
= clkspec
.args_count
? clkspec
.args
[0] : 0;
2486 /* if there is an indices property, use it to transfer the index
2487 * specified into an array offset for the clock-output-names property.
2489 of_property_for_each_u32(clkspec
.np
, "clock-indices", prop
, vp
, pv
) {
2497 if (of_property_read_string_index(clkspec
.np
, "clock-output-names",
2500 clk_name
= clkspec
.np
->name
;
2502 of_node_put(clkspec
.np
);
2505 EXPORT_SYMBOL_GPL(of_clk_get_parent_name
);
2507 struct clock_provider
{
2508 of_clk_init_cb_t clk_init_cb
;
2509 struct device_node
*np
;
2510 struct list_head node
;
2513 static LIST_HEAD(clk_provider_list
);
2516 * This function looks for a parent clock. If there is one, then it
2517 * checks that the provider for this parent clock was initialized, in
2518 * this case the parent clock will be ready.
2520 static int parent_ready(struct device_node
*np
)
2525 struct clk
*clk
= of_clk_get(np
, i
);
2527 /* this parent is ready we can check the next one */
2534 /* at least one parent is not ready, we exit now */
2535 if (PTR_ERR(clk
) == -EPROBE_DEFER
)
2539 * Here we make assumption that the device tree is
2540 * written correctly. So an error means that there is
2541 * no more parent. As we didn't exit yet, then the
2542 * previous parent are ready. If there is no clock
2543 * parent, no need to wait for them, then we can
2544 * consider their absence as being ready
2551 * of_clk_init() - Scan and init clock providers from the DT
2552 * @matches: array of compatible values and init functions for providers.
2554 * This function scans the device tree for matching clock providers
2555 * and calls their initialization functions. It also does it by trying
2556 * to follow the dependencies.
2558 void __init
of_clk_init(const struct of_device_id
*matches
)
2560 const struct of_device_id
*match
;
2561 struct device_node
*np
;
2562 struct clock_provider
*clk_provider
, *next
;
2567 matches
= &__clk_of_table
;
2569 /* First prepare the list of the clocks providers */
2570 for_each_matching_node_and_match(np
, matches
, &match
) {
2571 struct clock_provider
*parent
=
2572 kzalloc(sizeof(struct clock_provider
), GFP_KERNEL
);
2574 parent
->clk_init_cb
= match
->data
;
2576 list_add_tail(&parent
->node
, &clk_provider_list
);
2579 while (!list_empty(&clk_provider_list
)) {
2580 is_init_done
= false;
2581 list_for_each_entry_safe(clk_provider
, next
,
2582 &clk_provider_list
, node
) {
2583 if (force
|| parent_ready(clk_provider
->np
)) {
2585 clk_provider
->clk_init_cb(clk_provider
->np
);
2586 of_clk_set_defaults(clk_provider
->np
, true);
2588 list_del(&clk_provider
->node
);
2589 kfree(clk_provider
);
2590 is_init_done
= true;
2595 * We didn't manage to initialize any of the
2596 * remaining providers during the last loop, so now we
2597 * initialize all the remaining ones unconditionally
2598 * in case the clock parent was not mandatory