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;
103 static DEFINE_MUTEX(clk_debug_lock
);
104 static HLIST_HEAD(clk_debug_list
);
106 static struct hlist_head
*all_lists
[] = {
112 static struct hlist_head
*orphan_list
[] = {
117 static void clk_summary_show_one(struct seq_file
*s
, struct clk
*c
, int level
)
122 seq_printf(s
, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
124 30 - level
* 3, c
->name
,
125 c
->enable_count
, c
->prepare_count
, clk_get_rate(c
),
126 clk_get_accuracy(c
), clk_get_phase(c
));
129 static void clk_summary_show_subtree(struct seq_file
*s
, struct clk
*c
,
137 clk_summary_show_one(s
, c
, level
);
139 hlist_for_each_entry(child
, &c
->children
, child_node
)
140 clk_summary_show_subtree(s
, child
, level
+ 1);
143 static int clk_summary_show(struct seq_file
*s
, void *data
)
146 struct hlist_head
**lists
= (struct hlist_head
**)s
->private;
148 seq_puts(s
, " clock enable_cnt prepare_cnt rate accuracy phase\n");
149 seq_puts(s
, "----------------------------------------------------------------------------------------\n");
153 for (; *lists
; lists
++)
154 hlist_for_each_entry(c
, *lists
, child_node
)
155 clk_summary_show_subtree(s
, c
, 0);
157 clk_prepare_unlock();
163 static int clk_summary_open(struct inode
*inode
, struct file
*file
)
165 return single_open(file
, clk_summary_show
, inode
->i_private
);
168 static const struct file_operations clk_summary_fops
= {
169 .open
= clk_summary_open
,
172 .release
= single_release
,
175 static void clk_dump_one(struct seq_file
*s
, struct clk
*c
, int level
)
180 seq_printf(s
, "\"%s\": { ", c
->name
);
181 seq_printf(s
, "\"enable_count\": %d,", c
->enable_count
);
182 seq_printf(s
, "\"prepare_count\": %d,", c
->prepare_count
);
183 seq_printf(s
, "\"rate\": %lu", clk_get_rate(c
));
184 seq_printf(s
, "\"accuracy\": %lu", clk_get_accuracy(c
));
185 seq_printf(s
, "\"phase\": %d", clk_get_phase(c
));
188 static void clk_dump_subtree(struct seq_file
*s
, struct clk
*c
, int level
)
195 clk_dump_one(s
, c
, level
);
197 hlist_for_each_entry(child
, &c
->children
, child_node
) {
199 clk_dump_subtree(s
, child
, level
+ 1);
205 static int clk_dump(struct seq_file
*s
, void *data
)
208 bool first_node
= true;
209 struct hlist_head
**lists
= (struct hlist_head
**)s
->private;
215 for (; *lists
; lists
++) {
216 hlist_for_each_entry(c
, *lists
, child_node
) {
220 clk_dump_subtree(s
, c
, 0);
224 clk_prepare_unlock();
231 static int clk_dump_open(struct inode
*inode
, struct file
*file
)
233 return single_open(file
, clk_dump
, inode
->i_private
);
236 static const struct file_operations clk_dump_fops
= {
237 .open
= clk_dump_open
,
240 .release
= single_release
,
243 /* caller must hold prepare_lock */
244 static int clk_debug_create_one(struct clk
*clk
, struct dentry
*pdentry
)
249 if (!clk
|| !pdentry
) {
254 d
= debugfs_create_dir(clk
->name
, pdentry
);
260 d
= debugfs_create_u32("clk_rate", S_IRUGO
, clk
->dentry
,
265 d
= debugfs_create_u32("clk_accuracy", S_IRUGO
, clk
->dentry
,
266 (u32
*)&clk
->accuracy
);
270 d
= debugfs_create_u32("clk_phase", S_IRUGO
, clk
->dentry
,
275 d
= debugfs_create_x32("clk_flags", S_IRUGO
, clk
->dentry
,
280 d
= debugfs_create_u32("clk_prepare_count", S_IRUGO
, clk
->dentry
,
281 (u32
*)&clk
->prepare_count
);
285 d
= debugfs_create_u32("clk_enable_count", S_IRUGO
, clk
->dentry
,
286 (u32
*)&clk
->enable_count
);
290 d
= debugfs_create_u32("clk_notifier_count", S_IRUGO
, clk
->dentry
,
291 (u32
*)&clk
->notifier_count
);
295 if (clk
->ops
->debug_init
) {
296 ret
= clk
->ops
->debug_init(clk
->hw
, clk
->dentry
);
305 debugfs_remove_recursive(clk
->dentry
);
312 * clk_debug_register - add a clk node to the debugfs clk tree
313 * @clk: the clk being added to the debugfs clk tree
315 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
316 * initialized. Otherwise it bails out early since the debugfs clk tree
317 * will be created lazily by clk_debug_init as part of a late_initcall.
319 static int clk_debug_register(struct clk
*clk
)
323 mutex_lock(&clk_debug_lock
);
324 hlist_add_head(&clk
->debug_node
, &clk_debug_list
);
329 ret
= clk_debug_create_one(clk
, rootdir
);
331 mutex_unlock(&clk_debug_lock
);
337 * clk_debug_unregister - remove a clk node from the debugfs clk tree
338 * @clk: the clk being removed from the debugfs clk tree
340 * Dynamically removes a clk and all it's children clk nodes from the
341 * debugfs clk tree if clk->dentry points to debugfs created by
342 * clk_debug_register in __clk_init.
344 static void clk_debug_unregister(struct clk
*clk
)
346 mutex_lock(&clk_debug_lock
);
350 hlist_del_init(&clk
->debug_node
);
351 debugfs_remove_recursive(clk
->dentry
);
354 mutex_unlock(&clk_debug_lock
);
357 struct dentry
*clk_debugfs_add_file(struct clk
*clk
, char *name
, umode_t mode
,
358 void *data
, const struct file_operations
*fops
)
360 struct dentry
*d
= NULL
;
363 d
= debugfs_create_file(name
, mode
, clk
->dentry
, data
, fops
);
367 EXPORT_SYMBOL_GPL(clk_debugfs_add_file
);
370 * clk_debug_init - lazily create the debugfs clk tree visualization
372 * clks are often initialized very early during boot before memory can
373 * be dynamically allocated and well before debugfs is setup.
374 * clk_debug_init walks the clk tree hierarchy while holding
375 * prepare_lock and creates the topology as part of a late_initcall,
376 * thus insuring that clks initialized very early will still be
377 * represented in the debugfs clk tree. This function should only be
378 * called once at boot-time, and all other clks added dynamically will
379 * be done so with clk_debug_register.
381 static int __init
clk_debug_init(void)
386 rootdir
= debugfs_create_dir("clk", NULL
);
391 d
= debugfs_create_file("clk_summary", S_IRUGO
, rootdir
, &all_lists
,
396 d
= debugfs_create_file("clk_dump", S_IRUGO
, rootdir
, &all_lists
,
401 d
= debugfs_create_file("clk_orphan_summary", S_IRUGO
, rootdir
,
402 &orphan_list
, &clk_summary_fops
);
406 d
= debugfs_create_file("clk_orphan_dump", S_IRUGO
, rootdir
,
407 &orphan_list
, &clk_dump_fops
);
411 mutex_lock(&clk_debug_lock
);
412 hlist_for_each_entry(clk
, &clk_debug_list
, debug_node
)
413 clk_debug_create_one(clk
, rootdir
);
416 mutex_unlock(&clk_debug_lock
);
420 late_initcall(clk_debug_init
);
422 static inline int clk_debug_register(struct clk
*clk
) { return 0; }
423 static inline void clk_debug_reparent(struct clk
*clk
, struct clk
*new_parent
)
426 static inline void clk_debug_unregister(struct clk
*clk
)
431 /* caller must hold prepare_lock */
432 static void clk_unprepare_unused_subtree(struct clk
*clk
)
439 hlist_for_each_entry(child
, &clk
->children
, child_node
)
440 clk_unprepare_unused_subtree(child
);
442 if (clk
->prepare_count
)
445 if (clk
->flags
& CLK_IGNORE_UNUSED
)
448 if (__clk_is_prepared(clk
)) {
449 if (clk
->ops
->unprepare_unused
)
450 clk
->ops
->unprepare_unused(clk
->hw
);
451 else if (clk
->ops
->unprepare
)
452 clk
->ops
->unprepare(clk
->hw
);
456 /* caller must hold prepare_lock */
457 static void clk_disable_unused_subtree(struct clk
*clk
)
465 hlist_for_each_entry(child
, &clk
->children
, child_node
)
466 clk_disable_unused_subtree(child
);
468 flags
= clk_enable_lock();
470 if (clk
->enable_count
)
473 if (clk
->flags
& CLK_IGNORE_UNUSED
)
477 * some gate clocks have special needs during the disable-unused
478 * sequence. call .disable_unused if available, otherwise fall
481 if (__clk_is_enabled(clk
)) {
482 if (clk
->ops
->disable_unused
)
483 clk
->ops
->disable_unused(clk
->hw
);
484 else if (clk
->ops
->disable
)
485 clk
->ops
->disable(clk
->hw
);
489 clk_enable_unlock(flags
);
495 static bool clk_ignore_unused
;
496 static int __init
clk_ignore_unused_setup(char *__unused
)
498 clk_ignore_unused
= true;
501 __setup("clk_ignore_unused", clk_ignore_unused_setup
);
503 static int clk_disable_unused(void)
507 if (clk_ignore_unused
) {
508 pr_warn("clk: Not disabling unused clocks\n");
514 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
515 clk_disable_unused_subtree(clk
);
517 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
518 clk_disable_unused_subtree(clk
);
520 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
521 clk_unprepare_unused_subtree(clk
);
523 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
524 clk_unprepare_unused_subtree(clk
);
526 clk_prepare_unlock();
530 late_initcall_sync(clk_disable_unused
);
532 /*** helper functions ***/
534 const char *__clk_get_name(struct clk
*clk
)
536 return !clk
? NULL
: clk
->name
;
538 EXPORT_SYMBOL_GPL(__clk_get_name
);
540 struct clk_hw
*__clk_get_hw(struct clk
*clk
)
542 return !clk
? NULL
: clk
->hw
;
544 EXPORT_SYMBOL_GPL(__clk_get_hw
);
546 u8
__clk_get_num_parents(struct clk
*clk
)
548 return !clk
? 0 : clk
->num_parents
;
550 EXPORT_SYMBOL_GPL(__clk_get_num_parents
);
552 struct clk
*__clk_get_parent(struct clk
*clk
)
554 return !clk
? NULL
: clk
->parent
;
556 EXPORT_SYMBOL_GPL(__clk_get_parent
);
558 struct clk
*clk_get_parent_by_index(struct clk
*clk
, u8 index
)
560 if (!clk
|| index
>= clk
->num_parents
)
562 else if (!clk
->parents
)
563 return __clk_lookup(clk
->parent_names
[index
]);
564 else if (!clk
->parents
[index
])
565 return clk
->parents
[index
] =
566 __clk_lookup(clk
->parent_names
[index
]);
568 return clk
->parents
[index
];
570 EXPORT_SYMBOL_GPL(clk_get_parent_by_index
);
572 unsigned int __clk_get_enable_count(struct clk
*clk
)
574 return !clk
? 0 : clk
->enable_count
;
577 unsigned int __clk_get_prepare_count(struct clk
*clk
)
579 return !clk
? 0 : clk
->prepare_count
;
582 unsigned long __clk_get_rate(struct clk
*clk
)
593 if (clk
->flags
& CLK_IS_ROOT
)
602 EXPORT_SYMBOL_GPL(__clk_get_rate
);
604 unsigned long __clk_get_accuracy(struct clk
*clk
)
609 return clk
->accuracy
;
612 unsigned long __clk_get_flags(struct clk
*clk
)
614 return !clk
? 0 : clk
->flags
;
616 EXPORT_SYMBOL_GPL(__clk_get_flags
);
618 bool __clk_is_prepared(struct clk
*clk
)
626 * .is_prepared is optional for clocks that can prepare
627 * fall back to software usage counter if it is missing
629 if (!clk
->ops
->is_prepared
) {
630 ret
= clk
->prepare_count
? 1 : 0;
634 ret
= clk
->ops
->is_prepared(clk
->hw
);
639 bool __clk_is_enabled(struct clk
*clk
)
647 * .is_enabled is only mandatory for clocks that gate
648 * fall back to software usage counter if .is_enabled is missing
650 if (!clk
->ops
->is_enabled
) {
651 ret
= clk
->enable_count
? 1 : 0;
655 ret
= clk
->ops
->is_enabled(clk
->hw
);
659 EXPORT_SYMBOL_GPL(__clk_is_enabled
);
661 static struct clk
*__clk_lookup_subtree(const char *name
, struct clk
*clk
)
666 if (!strcmp(clk
->name
, name
))
669 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
670 ret
= __clk_lookup_subtree(name
, child
);
678 struct clk
*__clk_lookup(const char *name
)
680 struct clk
*root_clk
;
686 /* search the 'proper' clk tree first */
687 hlist_for_each_entry(root_clk
, &clk_root_list
, child_node
) {
688 ret
= __clk_lookup_subtree(name
, root_clk
);
693 /* if not found, then search the orphan tree */
694 hlist_for_each_entry(root_clk
, &clk_orphan_list
, child_node
) {
695 ret
= __clk_lookup_subtree(name
, root_clk
);
704 * Helper for finding best parent to provide a given frequency. This can be used
705 * directly as a determine_rate callback (e.g. for a mux), or from a more
706 * complex clock that may combine a mux with other operations.
708 long __clk_mux_determine_rate(struct clk_hw
*hw
, unsigned long rate
,
709 unsigned long *best_parent_rate
,
710 struct clk
**best_parent_p
)
712 struct clk
*clk
= hw
->clk
, *parent
, *best_parent
= NULL
;
714 unsigned long parent_rate
, best
= 0;
716 /* if NO_REPARENT flag set, pass through to current parent */
717 if (clk
->flags
& CLK_SET_RATE_NO_REPARENT
) {
718 parent
= clk
->parent
;
719 if (clk
->flags
& CLK_SET_RATE_PARENT
)
720 best
= __clk_round_rate(parent
, rate
);
722 best
= __clk_get_rate(parent
);
724 best
= __clk_get_rate(clk
);
728 /* find the parent that can provide the fastest rate <= rate */
729 num_parents
= clk
->num_parents
;
730 for (i
= 0; i
< num_parents
; i
++) {
731 parent
= clk_get_parent_by_index(clk
, i
);
734 if (clk
->flags
& CLK_SET_RATE_PARENT
)
735 parent_rate
= __clk_round_rate(parent
, rate
);
737 parent_rate
= __clk_get_rate(parent
);
738 if (parent_rate
<= rate
&& parent_rate
> best
) {
739 best_parent
= parent
;
746 *best_parent_p
= best_parent
;
747 *best_parent_rate
= best
;
751 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate
);
755 void __clk_unprepare(struct clk
*clk
)
760 if (WARN_ON(clk
->prepare_count
== 0))
763 if (--clk
->prepare_count
> 0)
766 WARN_ON(clk
->enable_count
> 0);
768 if (clk
->ops
->unprepare
)
769 clk
->ops
->unprepare(clk
->hw
);
771 __clk_unprepare(clk
->parent
);
775 * clk_unprepare - undo preparation of a clock source
776 * @clk: the clk being unprepared
778 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
779 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
780 * if the operation may sleep. One example is a clk which is accessed over
781 * I2c. In the complex case a clk gate operation may require a fast and a slow
782 * part. It is this reason that clk_unprepare and clk_disable are not mutually
783 * exclusive. In fact clk_disable must be called before clk_unprepare.
785 void clk_unprepare(struct clk
*clk
)
787 if (IS_ERR_OR_NULL(clk
))
791 __clk_unprepare(clk
);
792 clk_prepare_unlock();
794 EXPORT_SYMBOL_GPL(clk_unprepare
);
796 int __clk_prepare(struct clk
*clk
)
803 if (clk
->prepare_count
== 0) {
804 ret
= __clk_prepare(clk
->parent
);
808 if (clk
->ops
->prepare
) {
809 ret
= clk
->ops
->prepare(clk
->hw
);
811 __clk_unprepare(clk
->parent
);
817 clk
->prepare_count
++;
823 * clk_prepare - prepare a clock source
824 * @clk: the clk being prepared
826 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
827 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
828 * operation may sleep. One example is a clk which is accessed over I2c. In
829 * the complex case a clk ungate operation may require a fast and a slow part.
830 * It is this reason that clk_prepare and clk_enable are not mutually
831 * exclusive. In fact clk_prepare must be called before clk_enable.
832 * Returns 0 on success, -EERROR otherwise.
834 int clk_prepare(struct clk
*clk
)
839 ret
= __clk_prepare(clk
);
840 clk_prepare_unlock();
844 EXPORT_SYMBOL_GPL(clk_prepare
);
846 static void __clk_disable(struct clk
*clk
)
851 if (WARN_ON(clk
->enable_count
== 0))
854 if (--clk
->enable_count
> 0)
857 if (clk
->ops
->disable
)
858 clk
->ops
->disable(clk
->hw
);
860 __clk_disable(clk
->parent
);
864 * clk_disable - gate a clock
865 * @clk: the clk being gated
867 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
868 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
869 * clk if the operation is fast and will never sleep. One example is a
870 * SoC-internal clk which is controlled via simple register writes. In the
871 * complex case a clk gate operation may require a fast and a slow part. It is
872 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
873 * In fact clk_disable must be called before clk_unprepare.
875 void clk_disable(struct clk
*clk
)
879 if (IS_ERR_OR_NULL(clk
))
882 flags
= clk_enable_lock();
884 clk_enable_unlock(flags
);
886 EXPORT_SYMBOL_GPL(clk_disable
);
888 static int __clk_enable(struct clk
*clk
)
895 if (WARN_ON(clk
->prepare_count
== 0))
898 if (clk
->enable_count
== 0) {
899 ret
= __clk_enable(clk
->parent
);
904 if (clk
->ops
->enable
) {
905 ret
= clk
->ops
->enable(clk
->hw
);
907 __clk_disable(clk
->parent
);
918 * clk_enable - ungate a clock
919 * @clk: the clk being ungated
921 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
922 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
923 * if the operation will never sleep. One example is a SoC-internal clk which
924 * is controlled via simple register writes. In the complex case a clk ungate
925 * operation may require a fast and a slow part. It is this reason that
926 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
927 * must be called before clk_enable. Returns 0 on success, -EERROR
930 int clk_enable(struct clk
*clk
)
935 flags
= clk_enable_lock();
936 ret
= __clk_enable(clk
);
937 clk_enable_unlock(flags
);
941 EXPORT_SYMBOL_GPL(clk_enable
);
944 * __clk_round_rate - round the given rate for a clk
945 * @clk: round the rate of this clock
946 * @rate: the rate which is to be rounded
948 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
950 unsigned long __clk_round_rate(struct clk
*clk
, unsigned long rate
)
952 unsigned long parent_rate
= 0;
958 parent
= clk
->parent
;
960 parent_rate
= parent
->rate
;
962 if (clk
->ops
->determine_rate
)
963 return clk
->ops
->determine_rate(clk
->hw
, rate
, &parent_rate
,
965 else if (clk
->ops
->round_rate
)
966 return clk
->ops
->round_rate(clk
->hw
, rate
, &parent_rate
);
967 else if (clk
->flags
& CLK_SET_RATE_PARENT
)
968 return __clk_round_rate(clk
->parent
, rate
);
972 EXPORT_SYMBOL_GPL(__clk_round_rate
);
975 * clk_round_rate - round the given rate for a clk
976 * @clk: the clk for which we are rounding a rate
977 * @rate: the rate which is to be rounded
979 * Takes in a rate as input and rounds it to a rate that the clk can actually
980 * use which is then returned. If clk doesn't support round_rate operation
981 * then the parent rate is returned.
983 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
988 ret
= __clk_round_rate(clk
, rate
);
989 clk_prepare_unlock();
993 EXPORT_SYMBOL_GPL(clk_round_rate
);
996 * __clk_notify - call clk notifier chain
997 * @clk: struct clk * that is changing rate
998 * @msg: clk notifier type (see include/linux/clk.h)
999 * @old_rate: old clk rate
1000 * @new_rate: new clk rate
1002 * Triggers a notifier call chain on the clk rate-change notification
1003 * for 'clk'. Passes a pointer to the struct clk and the previous
1004 * and current rates to the notifier callback. Intended to be called by
1005 * internal clock code only. Returns NOTIFY_DONE from the last driver
1006 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1007 * a driver returns that.
1009 static int __clk_notify(struct clk
*clk
, unsigned long msg
,
1010 unsigned long old_rate
, unsigned long new_rate
)
1012 struct clk_notifier
*cn
;
1013 struct clk_notifier_data cnd
;
1014 int ret
= NOTIFY_DONE
;
1017 cnd
.old_rate
= old_rate
;
1018 cnd
.new_rate
= new_rate
;
1020 list_for_each_entry(cn
, &clk_notifier_list
, node
) {
1021 if (cn
->clk
== clk
) {
1022 ret
= srcu_notifier_call_chain(&cn
->notifier_head
, msg
,
1032 * __clk_recalc_accuracies
1033 * @clk: first clk in the subtree
1035 * Walks the subtree of clks starting with clk and recalculates accuracies as
1036 * it goes. Note that if a clk does not implement the .recalc_accuracy
1037 * callback then it is assumed that the clock will take on the accuracy of it's
1040 * Caller must hold prepare_lock.
1042 static void __clk_recalc_accuracies(struct clk
*clk
)
1044 unsigned long parent_accuracy
= 0;
1048 parent_accuracy
= clk
->parent
->accuracy
;
1050 if (clk
->ops
->recalc_accuracy
)
1051 clk
->accuracy
= clk
->ops
->recalc_accuracy(clk
->hw
,
1054 clk
->accuracy
= parent_accuracy
;
1056 hlist_for_each_entry(child
, &clk
->children
, child_node
)
1057 __clk_recalc_accuracies(child
);
1061 * clk_get_accuracy - return the accuracy of clk
1062 * @clk: the clk whose accuracy is being returned
1064 * Simply returns the cached accuracy of the clk, unless
1065 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1067 * If clk is NULL then returns 0.
1069 long clk_get_accuracy(struct clk
*clk
)
1071 unsigned long accuracy
;
1074 if (clk
&& (clk
->flags
& CLK_GET_ACCURACY_NOCACHE
))
1075 __clk_recalc_accuracies(clk
);
1077 accuracy
= __clk_get_accuracy(clk
);
1078 clk_prepare_unlock();
1082 EXPORT_SYMBOL_GPL(clk_get_accuracy
);
1084 static unsigned long clk_recalc(struct clk
*clk
, unsigned long parent_rate
)
1086 if (clk
->ops
->recalc_rate
)
1087 return clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
1092 * __clk_recalc_rates
1093 * @clk: first clk in the subtree
1094 * @msg: notification type (see include/linux/clk.h)
1096 * Walks the subtree of clks starting with clk and recalculates rates as it
1097 * goes. Note that if a clk does not implement the .recalc_rate callback then
1098 * it is assumed that the clock will take on the rate of its parent.
1100 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1103 * Caller must hold prepare_lock.
1105 static void __clk_recalc_rates(struct clk
*clk
, unsigned long msg
)
1107 unsigned long old_rate
;
1108 unsigned long parent_rate
= 0;
1111 old_rate
= clk
->rate
;
1114 parent_rate
= clk
->parent
->rate
;
1116 clk
->rate
= clk_recalc(clk
, parent_rate
);
1119 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1120 * & ABORT_RATE_CHANGE notifiers
1122 if (clk
->notifier_count
&& msg
)
1123 __clk_notify(clk
, msg
, old_rate
, clk
->rate
);
1125 hlist_for_each_entry(child
, &clk
->children
, child_node
)
1126 __clk_recalc_rates(child
, msg
);
1130 * clk_get_rate - return the rate of clk
1131 * @clk: the clk whose rate is being returned
1133 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1134 * is set, which means a recalc_rate will be issued.
1135 * If clk is NULL then returns 0.
1137 unsigned long clk_get_rate(struct clk
*clk
)
1143 if (clk
&& (clk
->flags
& CLK_GET_RATE_NOCACHE
))
1144 __clk_recalc_rates(clk
, 0);
1146 rate
= __clk_get_rate(clk
);
1147 clk_prepare_unlock();
1151 EXPORT_SYMBOL_GPL(clk_get_rate
);
1153 static int clk_fetch_parent_index(struct clk
*clk
, struct clk
*parent
)
1157 if (!clk
->parents
) {
1158 clk
->parents
= kcalloc(clk
->num_parents
,
1159 sizeof(struct clk
*), GFP_KERNEL
);
1165 * find index of new parent clock using cached parent ptrs,
1166 * or if not yet cached, use string name comparison and cache
1167 * them now to avoid future calls to __clk_lookup.
1169 for (i
= 0; i
< clk
->num_parents
; i
++) {
1170 if (clk
->parents
[i
] == parent
)
1173 if (clk
->parents
[i
])
1176 if (!strcmp(clk
->parent_names
[i
], parent
->name
)) {
1177 clk
->parents
[i
] = __clk_lookup(parent
->name
);
1185 static void clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1187 hlist_del(&clk
->child_node
);
1190 /* avoid duplicate POST_RATE_CHANGE notifications */
1191 if (new_parent
->new_child
== clk
)
1192 new_parent
->new_child
= NULL
;
1194 hlist_add_head(&clk
->child_node
, &new_parent
->children
);
1196 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1199 clk
->parent
= new_parent
;
1202 static struct clk
*__clk_set_parent_before(struct clk
*clk
, struct clk
*parent
)
1204 unsigned long flags
;
1205 struct clk
*old_parent
= clk
->parent
;
1208 * Migrate prepare state between parents and prevent race with
1211 * If the clock is not prepared, then a race with
1212 * clk_enable/disable() is impossible since we already have the
1213 * prepare lock (future calls to clk_enable() need to be preceded by
1216 * If the clock is prepared, migrate the prepared state to the new
1217 * parent and also protect against a race with clk_enable() by
1218 * forcing the clock and the new parent on. This ensures that all
1219 * future calls to clk_enable() are practically NOPs with respect to
1220 * hardware and software states.
1222 * See also: Comment for clk_set_parent() below.
1224 if (clk
->prepare_count
) {
1225 __clk_prepare(parent
);
1230 /* update the clk tree topology */
1231 flags
= clk_enable_lock();
1232 clk_reparent(clk
, parent
);
1233 clk_enable_unlock(flags
);
1238 static void __clk_set_parent_after(struct clk
*clk
, struct clk
*parent
,
1239 struct clk
*old_parent
)
1242 * Finish the migration of prepare state and undo the changes done
1243 * for preventing a race with clk_enable().
1245 if (clk
->prepare_count
) {
1247 clk_disable(old_parent
);
1248 __clk_unprepare(old_parent
);
1252 static int __clk_set_parent(struct clk
*clk
, struct clk
*parent
, u8 p_index
)
1254 unsigned long flags
;
1256 struct clk
*old_parent
;
1258 old_parent
= __clk_set_parent_before(clk
, parent
);
1260 /* change clock input source */
1261 if (parent
&& clk
->ops
->set_parent
)
1262 ret
= clk
->ops
->set_parent(clk
->hw
, p_index
);
1265 flags
= clk_enable_lock();
1266 clk_reparent(clk
, old_parent
);
1267 clk_enable_unlock(flags
);
1269 if (clk
->prepare_count
) {
1271 clk_disable(parent
);
1272 __clk_unprepare(parent
);
1277 __clk_set_parent_after(clk
, parent
, old_parent
);
1283 * __clk_speculate_rates
1284 * @clk: first clk in the subtree
1285 * @parent_rate: the "future" rate of clk's parent
1287 * Walks the subtree of clks starting with clk, speculating rates as it
1288 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1290 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1291 * pre-rate change notifications and returns early if no clks in the
1292 * subtree have subscribed to the notifications. Note that if a clk does not
1293 * implement the .recalc_rate callback then it is assumed that the clock will
1294 * take on the rate of its parent.
1296 * Caller must hold prepare_lock.
1298 static int __clk_speculate_rates(struct clk
*clk
, unsigned long parent_rate
)
1301 unsigned long new_rate
;
1302 int ret
= NOTIFY_DONE
;
1304 new_rate
= clk_recalc(clk
, parent_rate
);
1306 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1307 if (clk
->notifier_count
)
1308 ret
= __clk_notify(clk
, PRE_RATE_CHANGE
, clk
->rate
, new_rate
);
1310 if (ret
& NOTIFY_STOP_MASK
) {
1311 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1312 __func__
, clk
->name
, ret
);
1316 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1317 ret
= __clk_speculate_rates(child
, new_rate
);
1318 if (ret
& NOTIFY_STOP_MASK
)
1326 static void clk_calc_subtree(struct clk
*clk
, unsigned long new_rate
,
1327 struct clk
*new_parent
, u8 p_index
)
1331 clk
->new_rate
= new_rate
;
1332 clk
->new_parent
= new_parent
;
1333 clk
->new_parent_index
= p_index
;
1334 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1335 clk
->new_child
= NULL
;
1336 if (new_parent
&& new_parent
!= clk
->parent
)
1337 new_parent
->new_child
= clk
;
1339 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1340 child
->new_rate
= clk_recalc(child
, new_rate
);
1341 clk_calc_subtree(child
, child
->new_rate
, NULL
, 0);
1346 * calculate the new rates returning the topmost clock that has to be
1349 static struct clk
*clk_calc_new_rates(struct clk
*clk
, unsigned long rate
)
1351 struct clk
*top
= clk
;
1352 struct clk
*old_parent
, *parent
;
1353 unsigned long best_parent_rate
= 0;
1354 unsigned long new_rate
;
1358 if (IS_ERR_OR_NULL(clk
))
1361 /* save parent rate, if it exists */
1362 parent
= old_parent
= clk
->parent
;
1364 best_parent_rate
= parent
->rate
;
1366 /* find the closest rate and parent clk/rate */
1367 if (clk
->ops
->determine_rate
) {
1368 new_rate
= clk
->ops
->determine_rate(clk
->hw
, rate
,
1371 } else if (clk
->ops
->round_rate
) {
1372 new_rate
= clk
->ops
->round_rate(clk
->hw
, rate
,
1374 } else if (!parent
|| !(clk
->flags
& CLK_SET_RATE_PARENT
)) {
1375 /* pass-through clock without adjustable parent */
1376 clk
->new_rate
= clk
->rate
;
1379 /* pass-through clock with adjustable parent */
1380 top
= clk_calc_new_rates(parent
, rate
);
1381 new_rate
= parent
->new_rate
;
1385 /* some clocks must be gated to change parent */
1386 if (parent
!= old_parent
&&
1387 (clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1388 pr_debug("%s: %s not gated but wants to reparent\n",
1389 __func__
, clk
->name
);
1393 /* try finding the new parent index */
1395 p_index
= clk_fetch_parent_index(clk
, parent
);
1397 pr_debug("%s: clk %s can not be parent of clk %s\n",
1398 __func__
, parent
->name
, clk
->name
);
1403 if ((clk
->flags
& CLK_SET_RATE_PARENT
) && parent
&&
1404 best_parent_rate
!= parent
->rate
)
1405 top
= clk_calc_new_rates(parent
, best_parent_rate
);
1408 clk_calc_subtree(clk
, new_rate
, parent
, p_index
);
1414 * Notify about rate changes in a subtree. Always walk down the whole tree
1415 * so that in case of an error we can walk down the whole tree again and
1418 static struct clk
*clk_propagate_rate_change(struct clk
*clk
, unsigned long event
)
1420 struct clk
*child
, *tmp_clk
, *fail_clk
= NULL
;
1421 int ret
= NOTIFY_DONE
;
1423 if (clk
->rate
== clk
->new_rate
)
1426 if (clk
->notifier_count
) {
1427 ret
= __clk_notify(clk
, event
, clk
->rate
, clk
->new_rate
);
1428 if (ret
& NOTIFY_STOP_MASK
)
1432 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1433 /* Skip children who will be reparented to another clock */
1434 if (child
->new_parent
&& child
->new_parent
!= clk
)
1436 tmp_clk
= clk_propagate_rate_change(child
, event
);
1441 /* handle the new child who might not be in clk->children yet */
1442 if (clk
->new_child
) {
1443 tmp_clk
= clk_propagate_rate_change(clk
->new_child
, event
);
1452 * walk down a subtree and set the new rates notifying the rate
1455 static void clk_change_rate(struct clk
*clk
)
1458 struct hlist_node
*tmp
;
1459 unsigned long old_rate
;
1460 unsigned long best_parent_rate
= 0;
1461 bool skip_set_rate
= false;
1462 struct clk
*old_parent
;
1464 old_rate
= clk
->rate
;
1466 if (clk
->new_parent
)
1467 best_parent_rate
= clk
->new_parent
->rate
;
1468 else if (clk
->parent
)
1469 best_parent_rate
= clk
->parent
->rate
;
1471 if (clk
->new_parent
&& clk
->new_parent
!= clk
->parent
) {
1472 old_parent
= __clk_set_parent_before(clk
, clk
->new_parent
);
1474 if (clk
->ops
->set_rate_and_parent
) {
1475 skip_set_rate
= true;
1476 clk
->ops
->set_rate_and_parent(clk
->hw
, clk
->new_rate
,
1478 clk
->new_parent_index
);
1479 } else if (clk
->ops
->set_parent
) {
1480 clk
->ops
->set_parent(clk
->hw
, clk
->new_parent_index
);
1483 __clk_set_parent_after(clk
, clk
->new_parent
, old_parent
);
1486 if (!skip_set_rate
&& clk
->ops
->set_rate
)
1487 clk
->ops
->set_rate(clk
->hw
, clk
->new_rate
, best_parent_rate
);
1489 clk
->rate
= clk_recalc(clk
, best_parent_rate
);
1491 if (clk
->notifier_count
&& old_rate
!= clk
->rate
)
1492 __clk_notify(clk
, POST_RATE_CHANGE
, old_rate
, clk
->rate
);
1495 * Use safe iteration, as change_rate can actually swap parents
1496 * for certain clock types.
1498 hlist_for_each_entry_safe(child
, tmp
, &clk
->children
, child_node
) {
1499 /* Skip children who will be reparented to another clock */
1500 if (child
->new_parent
&& child
->new_parent
!= clk
)
1502 clk_change_rate(child
);
1505 /* handle the new child who might not be in clk->children yet */
1507 clk_change_rate(clk
->new_child
);
1511 * clk_set_rate - specify a new rate for clk
1512 * @clk: the clk whose rate is being changed
1513 * @rate: the new rate for clk
1515 * In the simplest case clk_set_rate will only adjust the rate of clk.
1517 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1518 * propagate up to clk's parent; whether or not this happens depends on the
1519 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1520 * after calling .round_rate then upstream parent propagation is ignored. If
1521 * *parent_rate comes back with a new rate for clk's parent then we propagate
1522 * up to clk's parent and set its rate. Upward propagation will continue
1523 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1524 * .round_rate stops requesting changes to clk's parent_rate.
1526 * Rate changes are accomplished via tree traversal that also recalculates the
1527 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1529 * Returns 0 on success, -EERROR otherwise.
1531 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
1533 struct clk
*top
, *fail_clk
;
1539 /* prevent racing with updates to the clock topology */
1542 /* bail early if nothing to do */
1543 if (rate
== clk_get_rate(clk
))
1546 if ((clk
->flags
& CLK_SET_RATE_GATE
) && clk
->prepare_count
) {
1551 /* calculate new rates and get the topmost changed clock */
1552 top
= clk_calc_new_rates(clk
, rate
);
1558 /* notify that we are about to change rates */
1559 fail_clk
= clk_propagate_rate_change(top
, PRE_RATE_CHANGE
);
1561 pr_debug("%s: failed to set %s rate\n", __func__
,
1563 clk_propagate_rate_change(top
, ABORT_RATE_CHANGE
);
1568 /* change the rates */
1569 clk_change_rate(top
);
1572 clk_prepare_unlock();
1576 EXPORT_SYMBOL_GPL(clk_set_rate
);
1579 * clk_get_parent - return the parent of a clk
1580 * @clk: the clk whose parent gets returned
1582 * Simply returns clk->parent. Returns NULL if clk is NULL.
1584 struct clk
*clk_get_parent(struct clk
*clk
)
1589 parent
= __clk_get_parent(clk
);
1590 clk_prepare_unlock();
1594 EXPORT_SYMBOL_GPL(clk_get_parent
);
1597 * .get_parent is mandatory for clocks with multiple possible parents. It is
1598 * optional for single-parent clocks. Always call .get_parent if it is
1599 * available and WARN if it is missing for multi-parent clocks.
1601 * For single-parent clocks without .get_parent, first check to see if the
1602 * .parents array exists, and if so use it to avoid an expensive tree
1603 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1605 static struct clk
*__clk_init_parent(struct clk
*clk
)
1607 struct clk
*ret
= NULL
;
1610 /* handle the trivial cases */
1612 if (!clk
->num_parents
)
1615 if (clk
->num_parents
== 1) {
1616 if (IS_ERR_OR_NULL(clk
->parent
))
1617 ret
= clk
->parent
= __clk_lookup(clk
->parent_names
[0]);
1622 if (!clk
->ops
->get_parent
) {
1623 WARN(!clk
->ops
->get_parent
,
1624 "%s: multi-parent clocks must implement .get_parent\n",
1630 * Do our best to cache parent clocks in clk->parents. This prevents
1631 * unnecessary and expensive calls to __clk_lookup. We don't set
1632 * clk->parent here; that is done by the calling function
1635 index
= clk
->ops
->get_parent(clk
->hw
);
1639 kcalloc(clk
->num_parents
, sizeof(struct clk
*),
1642 ret
= clk_get_parent_by_index(clk
, index
);
1648 void __clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1650 clk_reparent(clk
, new_parent
);
1651 __clk_recalc_accuracies(clk
);
1652 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1656 * clk_set_parent - switch the parent of a mux clk
1657 * @clk: the mux clk whose input we are switching
1658 * @parent: the new input to clk
1660 * Re-parent clk to use parent as its new input source. If clk is in
1661 * prepared state, the clk will get enabled for the duration of this call. If
1662 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1663 * that, the reparenting is glitchy in hardware, etc), use the
1664 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1666 * After successfully changing clk's parent clk_set_parent will update the
1667 * clk topology, sysfs topology and propagate rate recalculation via
1668 * __clk_recalc_rates.
1670 * Returns 0 on success, -EERROR otherwise.
1672 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
1676 unsigned long p_rate
= 0;
1681 /* verify ops for for multi-parent clks */
1682 if ((clk
->num_parents
> 1) && (!clk
->ops
->set_parent
))
1685 /* prevent racing with updates to the clock topology */
1688 if (clk
->parent
== parent
)
1691 /* check that we are allowed to re-parent if the clock is in use */
1692 if ((clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1697 /* try finding the new parent index */
1699 p_index
= clk_fetch_parent_index(clk
, parent
);
1700 p_rate
= parent
->rate
;
1702 pr_debug("%s: clk %s can not be parent of clk %s\n",
1703 __func__
, parent
->name
, clk
->name
);
1709 /* propagate PRE_RATE_CHANGE notifications */
1710 ret
= __clk_speculate_rates(clk
, p_rate
);
1712 /* abort if a driver objects */
1713 if (ret
& NOTIFY_STOP_MASK
)
1716 /* do the re-parent */
1717 ret
= __clk_set_parent(clk
, parent
, p_index
);
1719 /* propagate rate an accuracy recalculation accordingly */
1721 __clk_recalc_rates(clk
, ABORT_RATE_CHANGE
);
1723 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1724 __clk_recalc_accuracies(clk
);
1728 clk_prepare_unlock();
1732 EXPORT_SYMBOL_GPL(clk_set_parent
);
1735 * clk_set_phase - adjust the phase shift of a clock signal
1736 * @clk: clock signal source
1737 * @degrees: number of degrees the signal is shifted
1739 * Shifts the phase of a clock signal by the specified
1740 * degrees. Returns 0 on success, -EERROR otherwise.
1742 * This function makes no distinction about the input or reference
1743 * signal that we adjust the clock signal phase against. For example
1744 * phase locked-loop clock signal generators we may shift phase with
1745 * respect to feedback clock signal input, but for other cases the
1746 * clock phase may be shifted with respect to some other, unspecified
1749 * Additionally the concept of phase shift does not propagate through
1750 * the clock tree hierarchy, which sets it apart from clock rates and
1751 * clock accuracy. A parent clock phase attribute does not have an
1752 * impact on the phase attribute of a child clock.
1754 int clk_set_phase(struct clk
*clk
, int degrees
)
1761 /* sanity check degrees */
1768 if (!clk
->ops
->set_phase
)
1771 ret
= clk
->ops
->set_phase(clk
->hw
, degrees
);
1774 clk
->phase
= degrees
;
1777 clk_prepare_unlock();
1784 * clk_get_phase - return the phase shift of a clock signal
1785 * @clk: clock signal source
1787 * Returns the phase shift of a clock node in degrees, otherwise returns
1790 int clk_get_phase(struct clk
*clk
)
1799 clk_prepare_unlock();
1806 * __clk_init - initialize the data structures in a struct clk
1807 * @dev: device initializing this clk, placeholder for now
1808 * @clk: clk being initialized
1810 * Initializes the lists in struct clk, queries the hardware for the
1811 * parent and rate and sets them both.
1813 int __clk_init(struct device
*dev
, struct clk
*clk
)
1817 struct hlist_node
*tmp2
;
1824 /* check to see if a clock with this name is already registered */
1825 if (__clk_lookup(clk
->name
)) {
1826 pr_debug("%s: clk %s already initialized\n",
1827 __func__
, clk
->name
);
1832 /* check that clk_ops are sane. See Documentation/clk.txt */
1833 if (clk
->ops
->set_rate
&&
1834 !((clk
->ops
->round_rate
|| clk
->ops
->determine_rate
) &&
1835 clk
->ops
->recalc_rate
)) {
1836 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1837 __func__
, clk
->name
);
1842 if (clk
->ops
->set_parent
&& !clk
->ops
->get_parent
) {
1843 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1844 __func__
, clk
->name
);
1849 if (clk
->ops
->set_rate_and_parent
&&
1850 !(clk
->ops
->set_parent
&& clk
->ops
->set_rate
)) {
1851 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
1852 __func__
, clk
->name
);
1857 /* throw a WARN if any entries in parent_names are NULL */
1858 for (i
= 0; i
< clk
->num_parents
; i
++)
1859 WARN(!clk
->parent_names
[i
],
1860 "%s: invalid NULL in %s's .parent_names\n",
1861 __func__
, clk
->name
);
1864 * Allocate an array of struct clk *'s to avoid unnecessary string
1865 * look-ups of clk's possible parents. This can fail for clocks passed
1866 * in to clk_init during early boot; thus any access to clk->parents[]
1867 * must always check for a NULL pointer and try to populate it if
1870 * If clk->parents is not NULL we skip this entire block. This allows
1871 * for clock drivers to statically initialize clk->parents.
1873 if (clk
->num_parents
> 1 && !clk
->parents
) {
1874 clk
->parents
= kcalloc(clk
->num_parents
, sizeof(struct clk
*),
1877 * __clk_lookup returns NULL for parents that have not been
1878 * clk_init'd; thus any access to clk->parents[] must check
1879 * for a NULL pointer. We can always perform lazy lookups for
1880 * missing parents later on.
1883 for (i
= 0; i
< clk
->num_parents
; i
++)
1885 __clk_lookup(clk
->parent_names
[i
]);
1888 clk
->parent
= __clk_init_parent(clk
);
1891 * Populate clk->parent if parent has already been __clk_init'd. If
1892 * parent has not yet been __clk_init'd then place clk in the orphan
1893 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1896 * Every time a new clk is clk_init'd then we walk the list of orphan
1897 * clocks and re-parent any that are children of the clock currently
1901 hlist_add_head(&clk
->child_node
,
1902 &clk
->parent
->children
);
1903 else if (clk
->flags
& CLK_IS_ROOT
)
1904 hlist_add_head(&clk
->child_node
, &clk_root_list
);
1906 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1909 * Set clk's accuracy. The preferred method is to use
1910 * .recalc_accuracy. For simple clocks and lazy developers the default
1911 * fallback is to use the parent's accuracy. If a clock doesn't have a
1912 * parent (or is orphaned) then accuracy is set to zero (perfect
1915 if (clk
->ops
->recalc_accuracy
)
1916 clk
->accuracy
= clk
->ops
->recalc_accuracy(clk
->hw
,
1917 __clk_get_accuracy(clk
->parent
));
1918 else if (clk
->parent
)
1919 clk
->accuracy
= clk
->parent
->accuracy
;
1925 * Since a phase is by definition relative to its parent, just
1926 * query the current clock phase, or just assume it's in phase.
1928 if (clk
->ops
->get_phase
)
1929 clk
->phase
= clk
->ops
->get_phase(clk
->hw
);
1934 * Set clk's rate. The preferred method is to use .recalc_rate. For
1935 * simple clocks and lazy developers the default fallback is to use the
1936 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1937 * then rate is set to zero.
1939 if (clk
->ops
->recalc_rate
)
1940 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
,
1941 __clk_get_rate(clk
->parent
));
1942 else if (clk
->parent
)
1943 clk
->rate
= clk
->parent
->rate
;
1947 clk_debug_register(clk
);
1949 * walk the list of orphan clocks and reparent any that are children of
1952 hlist_for_each_entry_safe(orphan
, tmp2
, &clk_orphan_list
, child_node
) {
1953 if (orphan
->num_parents
&& orphan
->ops
->get_parent
) {
1954 i
= orphan
->ops
->get_parent(orphan
->hw
);
1955 if (!strcmp(clk
->name
, orphan
->parent_names
[i
]))
1956 __clk_reparent(orphan
, clk
);
1960 for (i
= 0; i
< orphan
->num_parents
; i
++)
1961 if (!strcmp(clk
->name
, orphan
->parent_names
[i
])) {
1962 __clk_reparent(orphan
, clk
);
1968 * optional platform-specific magic
1970 * The .init callback is not used by any of the basic clock types, but
1971 * exists for weird hardware that must perform initialization magic.
1972 * Please consider other ways of solving initialization problems before
1973 * using this callback, as its use is discouraged.
1976 clk
->ops
->init(clk
->hw
);
1978 kref_init(&clk
->ref
);
1980 clk_prepare_unlock();
1986 * __clk_register - register a clock and return a cookie.
1988 * Same as clk_register, except that the .clk field inside hw shall point to a
1989 * preallocated (generally statically allocated) struct clk. None of the fields
1990 * of the struct clk need to be initialized.
1992 * The data pointed to by .init and .clk field shall NOT be marked as init
1995 * __clk_register is only exposed via clk-private.h and is intended for use with
1996 * very large numbers of clocks that need to be statically initialized. It is
1997 * a layering violation to include clk-private.h from any code which implements
1998 * a clock's .ops; as such any statically initialized clock data MUST be in a
1999 * separate C file from the logic that implements its operations. Returns 0
2000 * on success, otherwise an error code.
2002 struct clk
*__clk_register(struct device
*dev
, struct clk_hw
*hw
)
2008 clk
->name
= hw
->init
->name
;
2009 clk
->ops
= hw
->init
->ops
;
2011 clk
->flags
= hw
->init
->flags
;
2012 clk
->parent_names
= hw
->init
->parent_names
;
2013 clk
->num_parents
= hw
->init
->num_parents
;
2014 if (dev
&& dev
->driver
)
2015 clk
->owner
= dev
->driver
->owner
;
2019 ret
= __clk_init(dev
, clk
);
2021 return ERR_PTR(ret
);
2025 EXPORT_SYMBOL_GPL(__clk_register
);
2028 * clk_register - allocate a new clock, register it and return an opaque cookie
2029 * @dev: device that is registering this clock
2030 * @hw: link to hardware-specific clock data
2032 * clk_register is the primary interface for populating the clock tree with new
2033 * clock nodes. It returns a pointer to the newly allocated struct clk which
2034 * cannot be dereferenced by driver code but may be used in conjuction with the
2035 * rest of the clock API. In the event of an error clk_register will return an
2036 * error code; drivers must test for an error code after calling clk_register.
2038 struct clk
*clk_register(struct device
*dev
, struct clk_hw
*hw
)
2043 clk
= kzalloc(sizeof(*clk
), GFP_KERNEL
);
2045 pr_err("%s: could not allocate clk\n", __func__
);
2050 clk
->name
= kstrdup(hw
->init
->name
, GFP_KERNEL
);
2052 pr_err("%s: could not allocate clk->name\n", __func__
);
2056 clk
->ops
= hw
->init
->ops
;
2057 if (dev
&& dev
->driver
)
2058 clk
->owner
= dev
->driver
->owner
;
2060 clk
->flags
= hw
->init
->flags
;
2061 clk
->num_parents
= hw
->init
->num_parents
;
2064 /* allocate local copy in case parent_names is __initdata */
2065 clk
->parent_names
= kcalloc(clk
->num_parents
, sizeof(char *),
2068 if (!clk
->parent_names
) {
2069 pr_err("%s: could not allocate clk->parent_names\n", __func__
);
2071 goto fail_parent_names
;
2075 /* copy each string name in case parent_names is __initdata */
2076 for (i
= 0; i
< clk
->num_parents
; i
++) {
2077 clk
->parent_names
[i
] = kstrdup(hw
->init
->parent_names
[i
],
2079 if (!clk
->parent_names
[i
]) {
2080 pr_err("%s: could not copy parent_names\n", __func__
);
2082 goto fail_parent_names_copy
;
2086 ret
= __clk_init(dev
, clk
);
2090 fail_parent_names_copy
:
2092 kfree(clk
->parent_names
[i
]);
2093 kfree(clk
->parent_names
);
2099 return ERR_PTR(ret
);
2101 EXPORT_SYMBOL_GPL(clk_register
);
2104 * Free memory allocated for a clock.
2105 * Caller must hold prepare_lock.
2107 static void __clk_release(struct kref
*ref
)
2109 struct clk
*clk
= container_of(ref
, struct clk
, ref
);
2110 int i
= clk
->num_parents
;
2112 kfree(clk
->parents
);
2114 kfree(clk
->parent_names
[i
]);
2116 kfree(clk
->parent_names
);
2122 * Empty clk_ops for unregistered clocks. These are used temporarily
2123 * after clk_unregister() was called on a clock and until last clock
2124 * consumer calls clk_put() and the struct clk object is freed.
2126 static int clk_nodrv_prepare_enable(struct clk_hw
*hw
)
2131 static void clk_nodrv_disable_unprepare(struct clk_hw
*hw
)
2136 static int clk_nodrv_set_rate(struct clk_hw
*hw
, unsigned long rate
,
2137 unsigned long parent_rate
)
2142 static int clk_nodrv_set_parent(struct clk_hw
*hw
, u8 index
)
2147 static const struct clk_ops clk_nodrv_ops
= {
2148 .enable
= clk_nodrv_prepare_enable
,
2149 .disable
= clk_nodrv_disable_unprepare
,
2150 .prepare
= clk_nodrv_prepare_enable
,
2151 .unprepare
= clk_nodrv_disable_unprepare
,
2152 .set_rate
= clk_nodrv_set_rate
,
2153 .set_parent
= clk_nodrv_set_parent
,
2157 * clk_unregister - unregister a currently registered clock
2158 * @clk: clock to unregister
2160 void clk_unregister(struct clk
*clk
)
2162 unsigned long flags
;
2164 if (!clk
|| WARN_ON_ONCE(IS_ERR(clk
)))
2167 clk_debug_unregister(clk
);
2171 if (clk
->ops
== &clk_nodrv_ops
) {
2172 pr_err("%s: unregistered clock: %s\n", __func__
, clk
->name
);
2176 * Assign empty clock ops for consumers that might still hold
2177 * a reference to this clock.
2179 flags
= clk_enable_lock();
2180 clk
->ops
= &clk_nodrv_ops
;
2181 clk_enable_unlock(flags
);
2183 if (!hlist_empty(&clk
->children
)) {
2185 struct hlist_node
*t
;
2187 /* Reparent all children to the orphan list. */
2188 hlist_for_each_entry_safe(child
, t
, &clk
->children
, child_node
)
2189 clk_set_parent(child
, NULL
);
2192 hlist_del_init(&clk
->child_node
);
2194 if (clk
->prepare_count
)
2195 pr_warn("%s: unregistering prepared clock: %s\n",
2196 __func__
, clk
->name
);
2197 kref_put(&clk
->ref
, __clk_release
);
2199 clk_prepare_unlock();
2201 EXPORT_SYMBOL_GPL(clk_unregister
);
2203 static void devm_clk_release(struct device
*dev
, void *res
)
2205 clk_unregister(*(struct clk
**)res
);
2209 * devm_clk_register - resource managed clk_register()
2210 * @dev: device that is registering this clock
2211 * @hw: link to hardware-specific clock data
2213 * Managed clk_register(). Clocks returned from this function are
2214 * automatically clk_unregister()ed on driver detach. See clk_register() for
2217 struct clk
*devm_clk_register(struct device
*dev
, struct clk_hw
*hw
)
2222 clkp
= devres_alloc(devm_clk_release
, sizeof(*clkp
), GFP_KERNEL
);
2224 return ERR_PTR(-ENOMEM
);
2226 clk
= clk_register(dev
, hw
);
2229 devres_add(dev
, clkp
);
2236 EXPORT_SYMBOL_GPL(devm_clk_register
);
2238 static int devm_clk_match(struct device
*dev
, void *res
, void *data
)
2240 struct clk
*c
= res
;
2247 * devm_clk_unregister - resource managed clk_unregister()
2248 * @clk: clock to unregister
2250 * Deallocate a clock allocated with devm_clk_register(). Normally
2251 * this function will not need to be called and the resource management
2252 * code will ensure that the resource is freed.
2254 void devm_clk_unregister(struct device
*dev
, struct clk
*clk
)
2256 WARN_ON(devres_release(dev
, devm_clk_release
, devm_clk_match
, clk
));
2258 EXPORT_SYMBOL_GPL(devm_clk_unregister
);
2263 int __clk_get(struct clk
*clk
)
2266 if (!try_module_get(clk
->owner
))
2269 kref_get(&clk
->ref
);
2274 void __clk_put(struct clk
*clk
)
2276 if (!clk
|| WARN_ON_ONCE(IS_ERR(clk
)))
2280 kref_put(&clk
->ref
, __clk_release
);
2281 clk_prepare_unlock();
2283 module_put(clk
->owner
);
2286 /*** clk rate change notifiers ***/
2289 * clk_notifier_register - add a clk rate change notifier
2290 * @clk: struct clk * to watch
2291 * @nb: struct notifier_block * with callback info
2293 * Request notification when clk's rate changes. This uses an SRCU
2294 * notifier because we want it to block and notifier unregistrations are
2295 * uncommon. The callbacks associated with the notifier must not
2296 * re-enter into the clk framework by calling any top-level clk APIs;
2297 * this will cause a nested prepare_lock mutex.
2299 * In all notification cases cases (pre, post and abort rate change) the
2300 * original clock rate is passed to the callback via struct
2301 * clk_notifier_data.old_rate and the new frequency is passed via struct
2302 * clk_notifier_data.new_rate.
2304 * clk_notifier_register() must be called from non-atomic context.
2305 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2306 * allocation failure; otherwise, passes along the return value of
2307 * srcu_notifier_chain_register().
2309 int clk_notifier_register(struct clk
*clk
, struct notifier_block
*nb
)
2311 struct clk_notifier
*cn
;
2319 /* search the list of notifiers for this clk */
2320 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2324 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2325 if (cn
->clk
!= clk
) {
2326 cn
= kzalloc(sizeof(struct clk_notifier
), GFP_KERNEL
);
2331 srcu_init_notifier_head(&cn
->notifier_head
);
2333 list_add(&cn
->node
, &clk_notifier_list
);
2336 ret
= srcu_notifier_chain_register(&cn
->notifier_head
, nb
);
2338 clk
->notifier_count
++;
2341 clk_prepare_unlock();
2345 EXPORT_SYMBOL_GPL(clk_notifier_register
);
2348 * clk_notifier_unregister - remove a clk rate change notifier
2349 * @clk: struct clk *
2350 * @nb: struct notifier_block * with callback info
2352 * Request no further notification for changes to 'clk' and frees memory
2353 * allocated in clk_notifier_register.
2355 * Returns -EINVAL if called with null arguments; otherwise, passes
2356 * along the return value of srcu_notifier_chain_unregister().
2358 int clk_notifier_unregister(struct clk
*clk
, struct notifier_block
*nb
)
2360 struct clk_notifier
*cn
= NULL
;
2368 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2372 if (cn
->clk
== clk
) {
2373 ret
= srcu_notifier_chain_unregister(&cn
->notifier_head
, nb
);
2375 clk
->notifier_count
--;
2377 /* XXX the notifier code should handle this better */
2378 if (!cn
->notifier_head
.head
) {
2379 srcu_cleanup_notifier_head(&cn
->notifier_head
);
2380 list_del(&cn
->node
);
2388 clk_prepare_unlock();
2392 EXPORT_SYMBOL_GPL(clk_notifier_unregister
);
2396 * struct of_clk_provider - Clock provider registration structure
2397 * @link: Entry in global list of clock providers
2398 * @node: Pointer to device tree node of clock provider
2399 * @get: Get clock callback. Returns NULL or a struct clk for the
2400 * given clock specifier
2401 * @data: context pointer to be passed into @get callback
2403 struct of_clk_provider
{
2404 struct list_head link
;
2406 struct device_node
*node
;
2407 struct clk
*(*get
)(struct of_phandle_args
*clkspec
, void *data
);
2411 static const struct of_device_id __clk_of_table_sentinel
2412 __used
__section(__clk_of_table_end
);
2414 static LIST_HEAD(of_clk_providers
);
2415 static DEFINE_MUTEX(of_clk_mutex
);
2417 /* of_clk_provider list locking helpers */
2418 void of_clk_lock(void)
2420 mutex_lock(&of_clk_mutex
);
2423 void of_clk_unlock(void)
2425 mutex_unlock(&of_clk_mutex
);
2428 struct clk
*of_clk_src_simple_get(struct of_phandle_args
*clkspec
,
2433 EXPORT_SYMBOL_GPL(of_clk_src_simple_get
);
2435 struct clk
*of_clk_src_onecell_get(struct of_phandle_args
*clkspec
, void *data
)
2437 struct clk_onecell_data
*clk_data
= data
;
2438 unsigned int idx
= clkspec
->args
[0];
2440 if (idx
>= clk_data
->clk_num
) {
2441 pr_err("%s: invalid clock index %d\n", __func__
, idx
);
2442 return ERR_PTR(-EINVAL
);
2445 return clk_data
->clks
[idx
];
2447 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get
);
2450 * of_clk_add_provider() - Register a clock provider for a node
2451 * @np: Device node pointer associated with clock provider
2452 * @clk_src_get: callback for decoding clock
2453 * @data: context pointer for @clk_src_get callback.
2455 int of_clk_add_provider(struct device_node
*np
,
2456 struct clk
*(*clk_src_get
)(struct of_phandle_args
*clkspec
,
2460 struct of_clk_provider
*cp
;
2463 cp
= kzalloc(sizeof(struct of_clk_provider
), GFP_KERNEL
);
2467 cp
->node
= of_node_get(np
);
2469 cp
->get
= clk_src_get
;
2471 mutex_lock(&of_clk_mutex
);
2472 list_add(&cp
->link
, &of_clk_providers
);
2473 mutex_unlock(&of_clk_mutex
);
2474 pr_debug("Added clock from %s\n", np
->full_name
);
2476 ret
= of_clk_set_defaults(np
, true);
2478 of_clk_del_provider(np
);
2482 EXPORT_SYMBOL_GPL(of_clk_add_provider
);
2485 * of_clk_del_provider() - Remove a previously registered clock provider
2486 * @np: Device node pointer associated with clock provider
2488 void of_clk_del_provider(struct device_node
*np
)
2490 struct of_clk_provider
*cp
;
2492 mutex_lock(&of_clk_mutex
);
2493 list_for_each_entry(cp
, &of_clk_providers
, link
) {
2494 if (cp
->node
== np
) {
2495 list_del(&cp
->link
);
2496 of_node_put(cp
->node
);
2501 mutex_unlock(&of_clk_mutex
);
2503 EXPORT_SYMBOL_GPL(of_clk_del_provider
);
2505 struct clk
*__of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2507 struct of_clk_provider
*provider
;
2508 struct clk
*clk
= ERR_PTR(-EPROBE_DEFER
);
2510 /* Check if we have such a provider in our array */
2511 list_for_each_entry(provider
, &of_clk_providers
, link
) {
2512 if (provider
->node
== clkspec
->np
)
2513 clk
= provider
->get(clkspec
, provider
->data
);
2521 struct clk
*of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2525 mutex_lock(&of_clk_mutex
);
2526 clk
= __of_clk_get_from_provider(clkspec
);
2527 mutex_unlock(&of_clk_mutex
);
2532 int of_clk_get_parent_count(struct device_node
*np
)
2534 return of_count_phandle_with_args(np
, "clocks", "#clock-cells");
2536 EXPORT_SYMBOL_GPL(of_clk_get_parent_count
);
2538 const char *of_clk_get_parent_name(struct device_node
*np
, int index
)
2540 struct of_phandle_args clkspec
;
2541 struct property
*prop
;
2542 const char *clk_name
;
2551 rc
= of_parse_phandle_with_args(np
, "clocks", "#clock-cells", index
,
2556 index
= clkspec
.args_count
? clkspec
.args
[0] : 0;
2559 /* if there is an indices property, use it to transfer the index
2560 * specified into an array offset for the clock-output-names property.
2562 of_property_for_each_u32(clkspec
.np
, "clock-indices", prop
, vp
, pv
) {
2570 if (of_property_read_string_index(clkspec
.np
, "clock-output-names",
2573 clk_name
= clkspec
.np
->name
;
2575 of_node_put(clkspec
.np
);
2578 EXPORT_SYMBOL_GPL(of_clk_get_parent_name
);
2580 struct clock_provider
{
2581 of_clk_init_cb_t clk_init_cb
;
2582 struct device_node
*np
;
2583 struct list_head node
;
2586 static LIST_HEAD(clk_provider_list
);
2589 * This function looks for a parent clock. If there is one, then it
2590 * checks that the provider for this parent clock was initialized, in
2591 * this case the parent clock will be ready.
2593 static int parent_ready(struct device_node
*np
)
2598 struct clk
*clk
= of_clk_get(np
, i
);
2600 /* this parent is ready we can check the next one */
2607 /* at least one parent is not ready, we exit now */
2608 if (PTR_ERR(clk
) == -EPROBE_DEFER
)
2612 * Here we make assumption that the device tree is
2613 * written correctly. So an error means that there is
2614 * no more parent. As we didn't exit yet, then the
2615 * previous parent are ready. If there is no clock
2616 * parent, no need to wait for them, then we can
2617 * consider their absence as being ready
2624 * of_clk_init() - Scan and init clock providers from the DT
2625 * @matches: array of compatible values and init functions for providers.
2627 * This function scans the device tree for matching clock providers
2628 * and calls their initialization functions. It also does it by trying
2629 * to follow the dependencies.
2631 void __init
of_clk_init(const struct of_device_id
*matches
)
2633 const struct of_device_id
*match
;
2634 struct device_node
*np
;
2635 struct clock_provider
*clk_provider
, *next
;
2640 matches
= &__clk_of_table
;
2642 /* First prepare the list of the clocks providers */
2643 for_each_matching_node_and_match(np
, matches
, &match
) {
2644 struct clock_provider
*parent
=
2645 kzalloc(sizeof(struct clock_provider
), GFP_KERNEL
);
2647 parent
->clk_init_cb
= match
->data
;
2649 list_add_tail(&parent
->node
, &clk_provider_list
);
2652 while (!list_empty(&clk_provider_list
)) {
2653 is_init_done
= false;
2654 list_for_each_entry_safe(clk_provider
, next
,
2655 &clk_provider_list
, node
) {
2656 if (force
|| parent_ready(clk_provider
->np
)) {
2658 clk_provider
->clk_init_cb(clk_provider
->np
);
2659 of_clk_set_defaults(clk_provider
->np
, true);
2661 list_del(&clk_provider
->node
);
2662 kfree(clk_provider
);
2663 is_init_done
= true;
2668 * We didn't manage to initialize any of the
2669 * remaining providers during the last loop, so now we
2670 * initialize all the remaining ones unconditionally
2671 * in case the clock parent was not mandatory