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 if (clk
->ops
->debug_init(clk
->hw
, clk
->dentry
))
295 debugfs_remove_recursive(clk
->dentry
);
301 /* caller must hold prepare_lock */
302 static int clk_debug_create_subtree(struct clk
*clk
, struct dentry
*pdentry
)
307 if (!clk
|| !pdentry
)
310 ret
= clk_debug_create_one(clk
, pdentry
);
315 hlist_for_each_entry(child
, &clk
->children
, child_node
)
316 clk_debug_create_subtree(child
, pdentry
);
324 * clk_debug_register - add a clk node to the debugfs clk tree
325 * @clk: the clk being added to the debugfs clk tree
327 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
328 * initialized. Otherwise it bails out early since the debugfs clk tree
329 * will be created lazily by clk_debug_init as part of a late_initcall.
331 * Caller must hold prepare_lock. Only clk_init calls this function (so
332 * far) so this is taken care.
334 static int clk_debug_register(struct clk
*clk
)
341 ret
= clk_debug_create_subtree(clk
, rootdir
);
348 * clk_debug_unregister - remove a clk node from the debugfs clk tree
349 * @clk: the clk being removed from the debugfs clk tree
351 * Dynamically removes a clk and all it's children clk nodes from the
352 * debugfs clk tree if clk->dentry points to debugfs created by
353 * clk_debug_register in __clk_init.
355 * Caller must hold prepare_lock.
357 static void clk_debug_unregister(struct clk
*clk
)
359 debugfs_remove_recursive(clk
->dentry
);
362 struct dentry
*clk_debugfs_add_file(struct clk
*clk
, char *name
, umode_t mode
,
363 void *data
, const struct file_operations
*fops
)
365 struct dentry
*d
= NULL
;
368 d
= debugfs_create_file(name
, mode
, clk
->dentry
, data
, fops
);
372 EXPORT_SYMBOL_GPL(clk_debugfs_add_file
);
375 * clk_debug_init - lazily create the debugfs clk tree visualization
377 * clks are often initialized very early during boot before memory can
378 * be dynamically allocated and well before debugfs is setup.
379 * clk_debug_init walks the clk tree hierarchy while holding
380 * prepare_lock and creates the topology as part of a late_initcall,
381 * thus insuring that clks initialized very early will still be
382 * represented in the debugfs clk tree. This function should only be
383 * called once at boot-time, and all other clks added dynamically will
384 * be done so with clk_debug_register.
386 static int __init
clk_debug_init(void)
391 rootdir
= debugfs_create_dir("clk", NULL
);
396 d
= debugfs_create_file("clk_summary", S_IRUGO
, rootdir
, &all_lists
,
401 d
= debugfs_create_file("clk_dump", S_IRUGO
, rootdir
, &all_lists
,
406 d
= debugfs_create_file("clk_orphan_summary", S_IRUGO
, rootdir
,
407 &orphan_list
, &clk_summary_fops
);
411 d
= debugfs_create_file("clk_orphan_dump", S_IRUGO
, rootdir
,
412 &orphan_list
, &clk_dump_fops
);
418 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
419 clk_debug_create_subtree(clk
, rootdir
);
421 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
422 clk_debug_create_subtree(clk
, rootdir
);
426 clk_prepare_unlock();
430 late_initcall(clk_debug_init
);
432 static inline int clk_debug_register(struct clk
*clk
) { return 0; }
433 static inline void clk_debug_reparent(struct clk
*clk
, struct clk
*new_parent
)
436 static inline void clk_debug_unregister(struct clk
*clk
)
441 /* caller must hold prepare_lock */
442 static void clk_unprepare_unused_subtree(struct clk
*clk
)
449 hlist_for_each_entry(child
, &clk
->children
, child_node
)
450 clk_unprepare_unused_subtree(child
);
452 if (clk
->prepare_count
)
455 if (clk
->flags
& CLK_IGNORE_UNUSED
)
458 if (__clk_is_prepared(clk
)) {
459 if (clk
->ops
->unprepare_unused
)
460 clk
->ops
->unprepare_unused(clk
->hw
);
461 else if (clk
->ops
->unprepare
)
462 clk
->ops
->unprepare(clk
->hw
);
466 /* caller must hold prepare_lock */
467 static void clk_disable_unused_subtree(struct clk
*clk
)
475 hlist_for_each_entry(child
, &clk
->children
, child_node
)
476 clk_disable_unused_subtree(child
);
478 flags
= clk_enable_lock();
480 if (clk
->enable_count
)
483 if (clk
->flags
& CLK_IGNORE_UNUSED
)
487 * some gate clocks have special needs during the disable-unused
488 * sequence. call .disable_unused if available, otherwise fall
491 if (__clk_is_enabled(clk
)) {
492 if (clk
->ops
->disable_unused
)
493 clk
->ops
->disable_unused(clk
->hw
);
494 else if (clk
->ops
->disable
)
495 clk
->ops
->disable(clk
->hw
);
499 clk_enable_unlock(flags
);
505 static bool clk_ignore_unused
;
506 static int __init
clk_ignore_unused_setup(char *__unused
)
508 clk_ignore_unused
= true;
511 __setup("clk_ignore_unused", clk_ignore_unused_setup
);
513 static int clk_disable_unused(void)
517 if (clk_ignore_unused
) {
518 pr_warn("clk: Not disabling unused clocks\n");
524 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
525 clk_disable_unused_subtree(clk
);
527 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
528 clk_disable_unused_subtree(clk
);
530 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
531 clk_unprepare_unused_subtree(clk
);
533 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
534 clk_unprepare_unused_subtree(clk
);
536 clk_prepare_unlock();
540 late_initcall_sync(clk_disable_unused
);
542 /*** helper functions ***/
544 const char *__clk_get_name(struct clk
*clk
)
546 return !clk
? NULL
: clk
->name
;
548 EXPORT_SYMBOL_GPL(__clk_get_name
);
550 struct clk_hw
*__clk_get_hw(struct clk
*clk
)
552 return !clk
? NULL
: clk
->hw
;
554 EXPORT_SYMBOL_GPL(__clk_get_hw
);
556 u8
__clk_get_num_parents(struct clk
*clk
)
558 return !clk
? 0 : clk
->num_parents
;
560 EXPORT_SYMBOL_GPL(__clk_get_num_parents
);
562 struct clk
*__clk_get_parent(struct clk
*clk
)
564 return !clk
? NULL
: clk
->parent
;
566 EXPORT_SYMBOL_GPL(__clk_get_parent
);
568 struct clk
*clk_get_parent_by_index(struct clk
*clk
, u8 index
)
570 if (!clk
|| index
>= clk
->num_parents
)
572 else if (!clk
->parents
)
573 return __clk_lookup(clk
->parent_names
[index
]);
574 else if (!clk
->parents
[index
])
575 return clk
->parents
[index
] =
576 __clk_lookup(clk
->parent_names
[index
]);
578 return clk
->parents
[index
];
580 EXPORT_SYMBOL_GPL(clk_get_parent_by_index
);
582 unsigned int __clk_get_enable_count(struct clk
*clk
)
584 return !clk
? 0 : clk
->enable_count
;
587 unsigned int __clk_get_prepare_count(struct clk
*clk
)
589 return !clk
? 0 : clk
->prepare_count
;
592 unsigned long __clk_get_rate(struct clk
*clk
)
603 if (clk
->flags
& CLK_IS_ROOT
)
612 EXPORT_SYMBOL_GPL(__clk_get_rate
);
614 unsigned long __clk_get_accuracy(struct clk
*clk
)
619 return clk
->accuracy
;
622 unsigned long __clk_get_flags(struct clk
*clk
)
624 return !clk
? 0 : clk
->flags
;
626 EXPORT_SYMBOL_GPL(__clk_get_flags
);
628 bool __clk_is_prepared(struct clk
*clk
)
636 * .is_prepared is optional for clocks that can prepare
637 * fall back to software usage counter if it is missing
639 if (!clk
->ops
->is_prepared
) {
640 ret
= clk
->prepare_count
? 1 : 0;
644 ret
= clk
->ops
->is_prepared(clk
->hw
);
649 bool __clk_is_enabled(struct clk
*clk
)
657 * .is_enabled is only mandatory for clocks that gate
658 * fall back to software usage counter if .is_enabled is missing
660 if (!clk
->ops
->is_enabled
) {
661 ret
= clk
->enable_count
? 1 : 0;
665 ret
= clk
->ops
->is_enabled(clk
->hw
);
669 EXPORT_SYMBOL_GPL(__clk_is_enabled
);
671 static struct clk
*__clk_lookup_subtree(const char *name
, struct clk
*clk
)
676 if (!strcmp(clk
->name
, name
))
679 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
680 ret
= __clk_lookup_subtree(name
, child
);
688 struct clk
*__clk_lookup(const char *name
)
690 struct clk
*root_clk
;
696 /* search the 'proper' clk tree first */
697 hlist_for_each_entry(root_clk
, &clk_root_list
, child_node
) {
698 ret
= __clk_lookup_subtree(name
, root_clk
);
703 /* if not found, then search the orphan tree */
704 hlist_for_each_entry(root_clk
, &clk_orphan_list
, child_node
) {
705 ret
= __clk_lookup_subtree(name
, root_clk
);
714 * Helper for finding best parent to provide a given frequency. This can be used
715 * directly as a determine_rate callback (e.g. for a mux), or from a more
716 * complex clock that may combine a mux with other operations.
718 long __clk_mux_determine_rate(struct clk_hw
*hw
, unsigned long rate
,
719 unsigned long *best_parent_rate
,
720 struct clk
**best_parent_p
)
722 struct clk
*clk
= hw
->clk
, *parent
, *best_parent
= NULL
;
724 unsigned long parent_rate
, best
= 0;
726 /* if NO_REPARENT flag set, pass through to current parent */
727 if (clk
->flags
& CLK_SET_RATE_NO_REPARENT
) {
728 parent
= clk
->parent
;
729 if (clk
->flags
& CLK_SET_RATE_PARENT
)
730 best
= __clk_round_rate(parent
, rate
);
732 best
= __clk_get_rate(parent
);
734 best
= __clk_get_rate(clk
);
738 /* find the parent that can provide the fastest rate <= rate */
739 num_parents
= clk
->num_parents
;
740 for (i
= 0; i
< num_parents
; i
++) {
741 parent
= clk_get_parent_by_index(clk
, i
);
744 if (clk
->flags
& CLK_SET_RATE_PARENT
)
745 parent_rate
= __clk_round_rate(parent
, rate
);
747 parent_rate
= __clk_get_rate(parent
);
748 if (parent_rate
<= rate
&& parent_rate
> best
) {
749 best_parent
= parent
;
756 *best_parent_p
= best_parent
;
757 *best_parent_rate
= best
;
761 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate
);
765 void __clk_unprepare(struct clk
*clk
)
770 if (WARN_ON(clk
->prepare_count
== 0))
773 if (--clk
->prepare_count
> 0)
776 WARN_ON(clk
->enable_count
> 0);
778 if (clk
->ops
->unprepare
)
779 clk
->ops
->unprepare(clk
->hw
);
781 __clk_unprepare(clk
->parent
);
785 * clk_unprepare - undo preparation of a clock source
786 * @clk: the clk being unprepared
788 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
789 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
790 * if the operation may sleep. One example is a clk which is accessed over
791 * I2c. In the complex case a clk gate operation may require a fast and a slow
792 * part. It is this reason that clk_unprepare and clk_disable are not mutually
793 * exclusive. In fact clk_disable must be called before clk_unprepare.
795 void clk_unprepare(struct clk
*clk
)
797 if (IS_ERR_OR_NULL(clk
))
801 __clk_unprepare(clk
);
802 clk_prepare_unlock();
804 EXPORT_SYMBOL_GPL(clk_unprepare
);
806 int __clk_prepare(struct clk
*clk
)
813 if (clk
->prepare_count
== 0) {
814 ret
= __clk_prepare(clk
->parent
);
818 if (clk
->ops
->prepare
) {
819 ret
= clk
->ops
->prepare(clk
->hw
);
821 __clk_unprepare(clk
->parent
);
827 clk
->prepare_count
++;
833 * clk_prepare - prepare a clock source
834 * @clk: the clk being prepared
836 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
837 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
838 * operation may sleep. One example is a clk which is accessed over I2c. In
839 * the complex case a clk ungate operation may require a fast and a slow part.
840 * It is this reason that clk_prepare and clk_enable are not mutually
841 * exclusive. In fact clk_prepare must be called before clk_enable.
842 * Returns 0 on success, -EERROR otherwise.
844 int clk_prepare(struct clk
*clk
)
849 ret
= __clk_prepare(clk
);
850 clk_prepare_unlock();
854 EXPORT_SYMBOL_GPL(clk_prepare
);
856 static void __clk_disable(struct clk
*clk
)
861 if (WARN_ON(clk
->enable_count
== 0))
864 if (--clk
->enable_count
> 0)
867 if (clk
->ops
->disable
)
868 clk
->ops
->disable(clk
->hw
);
870 __clk_disable(clk
->parent
);
874 * clk_disable - gate a clock
875 * @clk: the clk being gated
877 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
878 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
879 * clk if the operation is fast and will never sleep. One example is a
880 * SoC-internal clk which is controlled via simple register writes. In the
881 * complex case a clk gate operation may require a fast and a slow part. It is
882 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
883 * In fact clk_disable must be called before clk_unprepare.
885 void clk_disable(struct clk
*clk
)
889 if (IS_ERR_OR_NULL(clk
))
892 flags
= clk_enable_lock();
894 clk_enable_unlock(flags
);
896 EXPORT_SYMBOL_GPL(clk_disable
);
898 static int __clk_enable(struct clk
*clk
)
905 if (WARN_ON(clk
->prepare_count
== 0))
908 if (clk
->enable_count
== 0) {
909 ret
= __clk_enable(clk
->parent
);
914 if (clk
->ops
->enable
) {
915 ret
= clk
->ops
->enable(clk
->hw
);
917 __clk_disable(clk
->parent
);
928 * clk_enable - ungate a clock
929 * @clk: the clk being ungated
931 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
932 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
933 * if the operation will never sleep. One example is a SoC-internal clk which
934 * is controlled via simple register writes. In the complex case a clk ungate
935 * operation may require a fast and a slow part. It is this reason that
936 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
937 * must be called before clk_enable. Returns 0 on success, -EERROR
940 int clk_enable(struct clk
*clk
)
945 flags
= clk_enable_lock();
946 ret
= __clk_enable(clk
);
947 clk_enable_unlock(flags
);
951 EXPORT_SYMBOL_GPL(clk_enable
);
954 * __clk_round_rate - round the given rate for a clk
955 * @clk: round the rate of this clock
956 * @rate: the rate which is to be rounded
958 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
960 unsigned long __clk_round_rate(struct clk
*clk
, unsigned long rate
)
962 unsigned long parent_rate
= 0;
968 parent
= clk
->parent
;
970 parent_rate
= parent
->rate
;
972 if (clk
->ops
->determine_rate
)
973 return clk
->ops
->determine_rate(clk
->hw
, rate
, &parent_rate
,
975 else if (clk
->ops
->round_rate
)
976 return clk
->ops
->round_rate(clk
->hw
, rate
, &parent_rate
);
977 else if (clk
->flags
& CLK_SET_RATE_PARENT
)
978 return __clk_round_rate(clk
->parent
, rate
);
982 EXPORT_SYMBOL_GPL(__clk_round_rate
);
985 * clk_round_rate - round the given rate for a clk
986 * @clk: the clk for which we are rounding a rate
987 * @rate: the rate which is to be rounded
989 * Takes in a rate as input and rounds it to a rate that the clk can actually
990 * use which is then returned. If clk doesn't support round_rate operation
991 * then the parent rate is returned.
993 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
998 ret
= __clk_round_rate(clk
, rate
);
999 clk_prepare_unlock();
1003 EXPORT_SYMBOL_GPL(clk_round_rate
);
1006 * __clk_notify - call clk notifier chain
1007 * @clk: struct clk * that is changing rate
1008 * @msg: clk notifier type (see include/linux/clk.h)
1009 * @old_rate: old clk rate
1010 * @new_rate: new clk rate
1012 * Triggers a notifier call chain on the clk rate-change notification
1013 * for 'clk'. Passes a pointer to the struct clk and the previous
1014 * and current rates to the notifier callback. Intended to be called by
1015 * internal clock code only. Returns NOTIFY_DONE from the last driver
1016 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1017 * a driver returns that.
1019 static int __clk_notify(struct clk
*clk
, unsigned long msg
,
1020 unsigned long old_rate
, unsigned long new_rate
)
1022 struct clk_notifier
*cn
;
1023 struct clk_notifier_data cnd
;
1024 int ret
= NOTIFY_DONE
;
1027 cnd
.old_rate
= old_rate
;
1028 cnd
.new_rate
= new_rate
;
1030 list_for_each_entry(cn
, &clk_notifier_list
, node
) {
1031 if (cn
->clk
== clk
) {
1032 ret
= srcu_notifier_call_chain(&cn
->notifier_head
, msg
,
1042 * __clk_recalc_accuracies
1043 * @clk: first clk in the subtree
1045 * Walks the subtree of clks starting with clk and recalculates accuracies as
1046 * it goes. Note that if a clk does not implement the .recalc_accuracy
1047 * callback then it is assumed that the clock will take on the accuracy of it's
1050 * Caller must hold prepare_lock.
1052 static void __clk_recalc_accuracies(struct clk
*clk
)
1054 unsigned long parent_accuracy
= 0;
1058 parent_accuracy
= clk
->parent
->accuracy
;
1060 if (clk
->ops
->recalc_accuracy
)
1061 clk
->accuracy
= clk
->ops
->recalc_accuracy(clk
->hw
,
1064 clk
->accuracy
= parent_accuracy
;
1066 hlist_for_each_entry(child
, &clk
->children
, child_node
)
1067 __clk_recalc_accuracies(child
);
1071 * clk_get_accuracy - return the accuracy of clk
1072 * @clk: the clk whose accuracy is being returned
1074 * Simply returns the cached accuracy of the clk, unless
1075 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1077 * If clk is NULL then returns 0.
1079 long clk_get_accuracy(struct clk
*clk
)
1081 unsigned long accuracy
;
1084 if (clk
&& (clk
->flags
& CLK_GET_ACCURACY_NOCACHE
))
1085 __clk_recalc_accuracies(clk
);
1087 accuracy
= __clk_get_accuracy(clk
);
1088 clk_prepare_unlock();
1092 EXPORT_SYMBOL_GPL(clk_get_accuracy
);
1094 static unsigned long clk_recalc(struct clk
*clk
, unsigned long parent_rate
)
1096 if (clk
->ops
->recalc_rate
)
1097 return clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
1102 * __clk_recalc_rates
1103 * @clk: first clk in the subtree
1104 * @msg: notification type (see include/linux/clk.h)
1106 * Walks the subtree of clks starting with clk and recalculates rates as it
1107 * goes. Note that if a clk does not implement the .recalc_rate callback then
1108 * it is assumed that the clock will take on the rate of its parent.
1110 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1113 * Caller must hold prepare_lock.
1115 static void __clk_recalc_rates(struct clk
*clk
, unsigned long msg
)
1117 unsigned long old_rate
;
1118 unsigned long parent_rate
= 0;
1121 old_rate
= clk
->rate
;
1124 parent_rate
= clk
->parent
->rate
;
1126 clk
->rate
= clk_recalc(clk
, parent_rate
);
1129 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1130 * & ABORT_RATE_CHANGE notifiers
1132 if (clk
->notifier_count
&& msg
)
1133 __clk_notify(clk
, msg
, old_rate
, clk
->rate
);
1135 hlist_for_each_entry(child
, &clk
->children
, child_node
)
1136 __clk_recalc_rates(child
, msg
);
1140 * clk_get_rate - return the rate of clk
1141 * @clk: the clk whose rate is being returned
1143 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1144 * is set, which means a recalc_rate will be issued.
1145 * If clk is NULL then returns 0.
1147 unsigned long clk_get_rate(struct clk
*clk
)
1153 if (clk
&& (clk
->flags
& CLK_GET_RATE_NOCACHE
))
1154 __clk_recalc_rates(clk
, 0);
1156 rate
= __clk_get_rate(clk
);
1157 clk_prepare_unlock();
1161 EXPORT_SYMBOL_GPL(clk_get_rate
);
1163 static int clk_fetch_parent_index(struct clk
*clk
, struct clk
*parent
)
1167 if (!clk
->parents
) {
1168 clk
->parents
= kcalloc(clk
->num_parents
,
1169 sizeof(struct clk
*), GFP_KERNEL
);
1175 * find index of new parent clock using cached parent ptrs,
1176 * or if not yet cached, use string name comparison and cache
1177 * them now to avoid future calls to __clk_lookup.
1179 for (i
= 0; i
< clk
->num_parents
; i
++) {
1180 if (clk
->parents
[i
] == parent
)
1183 if (clk
->parents
[i
])
1186 if (!strcmp(clk
->parent_names
[i
], parent
->name
)) {
1187 clk
->parents
[i
] = __clk_lookup(parent
->name
);
1195 static void clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1197 hlist_del(&clk
->child_node
);
1200 /* avoid duplicate POST_RATE_CHANGE notifications */
1201 if (new_parent
->new_child
== clk
)
1202 new_parent
->new_child
= NULL
;
1204 hlist_add_head(&clk
->child_node
, &new_parent
->children
);
1206 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1209 clk
->parent
= new_parent
;
1212 static struct clk
*__clk_set_parent_before(struct clk
*clk
, struct clk
*parent
)
1214 unsigned long flags
;
1215 struct clk
*old_parent
= clk
->parent
;
1218 * Migrate prepare state between parents and prevent race with
1221 * If the clock is not prepared, then a race with
1222 * clk_enable/disable() is impossible since we already have the
1223 * prepare lock (future calls to clk_enable() need to be preceded by
1226 * If the clock is prepared, migrate the prepared state to the new
1227 * parent and also protect against a race with clk_enable() by
1228 * forcing the clock and the new parent on. This ensures that all
1229 * future calls to clk_enable() are practically NOPs with respect to
1230 * hardware and software states.
1232 * See also: Comment for clk_set_parent() below.
1234 if (clk
->prepare_count
) {
1235 __clk_prepare(parent
);
1240 /* update the clk tree topology */
1241 flags
= clk_enable_lock();
1242 clk_reparent(clk
, parent
);
1243 clk_enable_unlock(flags
);
1248 static void __clk_set_parent_after(struct clk
*clk
, struct clk
*parent
,
1249 struct clk
*old_parent
)
1252 * Finish the migration of prepare state and undo the changes done
1253 * for preventing a race with clk_enable().
1255 if (clk
->prepare_count
) {
1257 clk_disable(old_parent
);
1258 __clk_unprepare(old_parent
);
1262 static int __clk_set_parent(struct clk
*clk
, struct clk
*parent
, u8 p_index
)
1264 unsigned long flags
;
1266 struct clk
*old_parent
;
1268 old_parent
= __clk_set_parent_before(clk
, parent
);
1270 /* change clock input source */
1271 if (parent
&& clk
->ops
->set_parent
)
1272 ret
= clk
->ops
->set_parent(clk
->hw
, p_index
);
1275 flags
= clk_enable_lock();
1276 clk_reparent(clk
, old_parent
);
1277 clk_enable_unlock(flags
);
1279 if (clk
->prepare_count
) {
1281 clk_disable(parent
);
1282 __clk_unprepare(parent
);
1287 __clk_set_parent_after(clk
, parent
, old_parent
);
1293 * __clk_speculate_rates
1294 * @clk: first clk in the subtree
1295 * @parent_rate: the "future" rate of clk's parent
1297 * Walks the subtree of clks starting with clk, speculating rates as it
1298 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1300 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1301 * pre-rate change notifications and returns early if no clks in the
1302 * subtree have subscribed to the notifications. Note that if a clk does not
1303 * implement the .recalc_rate callback then it is assumed that the clock will
1304 * take on the rate of its parent.
1306 * Caller must hold prepare_lock.
1308 static int __clk_speculate_rates(struct clk
*clk
, unsigned long parent_rate
)
1311 unsigned long new_rate
;
1312 int ret
= NOTIFY_DONE
;
1314 new_rate
= clk_recalc(clk
, parent_rate
);
1316 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1317 if (clk
->notifier_count
)
1318 ret
= __clk_notify(clk
, PRE_RATE_CHANGE
, clk
->rate
, new_rate
);
1320 if (ret
& NOTIFY_STOP_MASK
) {
1321 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1322 __func__
, clk
->name
, ret
);
1326 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1327 ret
= __clk_speculate_rates(child
, new_rate
);
1328 if (ret
& NOTIFY_STOP_MASK
)
1336 static void clk_calc_subtree(struct clk
*clk
, unsigned long new_rate
,
1337 struct clk
*new_parent
, u8 p_index
)
1341 clk
->new_rate
= new_rate
;
1342 clk
->new_parent
= new_parent
;
1343 clk
->new_parent_index
= p_index
;
1344 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1345 clk
->new_child
= NULL
;
1346 if (new_parent
&& new_parent
!= clk
->parent
)
1347 new_parent
->new_child
= clk
;
1349 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1350 child
->new_rate
= clk_recalc(child
, new_rate
);
1351 clk_calc_subtree(child
, child
->new_rate
, NULL
, 0);
1356 * calculate the new rates returning the topmost clock that has to be
1359 static struct clk
*clk_calc_new_rates(struct clk
*clk
, unsigned long rate
)
1361 struct clk
*top
= clk
;
1362 struct clk
*old_parent
, *parent
;
1363 unsigned long best_parent_rate
= 0;
1364 unsigned long new_rate
;
1368 if (IS_ERR_OR_NULL(clk
))
1371 /* save parent rate, if it exists */
1372 parent
= old_parent
= clk
->parent
;
1374 best_parent_rate
= parent
->rate
;
1376 /* find the closest rate and parent clk/rate */
1377 if (clk
->ops
->determine_rate
) {
1378 new_rate
= clk
->ops
->determine_rate(clk
->hw
, rate
,
1381 } else if (clk
->ops
->round_rate
) {
1382 new_rate
= clk
->ops
->round_rate(clk
->hw
, rate
,
1384 } else if (!parent
|| !(clk
->flags
& CLK_SET_RATE_PARENT
)) {
1385 /* pass-through clock without adjustable parent */
1386 clk
->new_rate
= clk
->rate
;
1389 /* pass-through clock with adjustable parent */
1390 top
= clk_calc_new_rates(parent
, rate
);
1391 new_rate
= parent
->new_rate
;
1395 /* some clocks must be gated to change parent */
1396 if (parent
!= old_parent
&&
1397 (clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1398 pr_debug("%s: %s not gated but wants to reparent\n",
1399 __func__
, clk
->name
);
1403 /* try finding the new parent index */
1405 p_index
= clk_fetch_parent_index(clk
, parent
);
1407 pr_debug("%s: clk %s can not be parent of clk %s\n",
1408 __func__
, parent
->name
, clk
->name
);
1413 if ((clk
->flags
& CLK_SET_RATE_PARENT
) && parent
&&
1414 best_parent_rate
!= parent
->rate
)
1415 top
= clk_calc_new_rates(parent
, best_parent_rate
);
1418 clk_calc_subtree(clk
, new_rate
, parent
, p_index
);
1424 * Notify about rate changes in a subtree. Always walk down the whole tree
1425 * so that in case of an error we can walk down the whole tree again and
1428 static struct clk
*clk_propagate_rate_change(struct clk
*clk
, unsigned long event
)
1430 struct clk
*child
, *tmp_clk
, *fail_clk
= NULL
;
1431 int ret
= NOTIFY_DONE
;
1433 if (clk
->rate
== clk
->new_rate
)
1436 if (clk
->notifier_count
) {
1437 ret
= __clk_notify(clk
, event
, clk
->rate
, clk
->new_rate
);
1438 if (ret
& NOTIFY_STOP_MASK
)
1442 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1443 /* Skip children who will be reparented to another clock */
1444 if (child
->new_parent
&& child
->new_parent
!= clk
)
1446 tmp_clk
= clk_propagate_rate_change(child
, event
);
1451 /* handle the new child who might not be in clk->children yet */
1452 if (clk
->new_child
) {
1453 tmp_clk
= clk_propagate_rate_change(clk
->new_child
, event
);
1462 * walk down a subtree and set the new rates notifying the rate
1465 static void clk_change_rate(struct clk
*clk
)
1468 unsigned long old_rate
;
1469 unsigned long best_parent_rate
= 0;
1470 bool skip_set_rate
= false;
1471 struct clk
*old_parent
;
1473 old_rate
= clk
->rate
;
1475 if (clk
->new_parent
)
1476 best_parent_rate
= clk
->new_parent
->rate
;
1477 else if (clk
->parent
)
1478 best_parent_rate
= clk
->parent
->rate
;
1480 if (clk
->new_parent
&& clk
->new_parent
!= clk
->parent
) {
1481 old_parent
= __clk_set_parent_before(clk
, clk
->new_parent
);
1483 if (clk
->ops
->set_rate_and_parent
) {
1484 skip_set_rate
= true;
1485 clk
->ops
->set_rate_and_parent(clk
->hw
, clk
->new_rate
,
1487 clk
->new_parent_index
);
1488 } else if (clk
->ops
->set_parent
) {
1489 clk
->ops
->set_parent(clk
->hw
, clk
->new_parent_index
);
1492 __clk_set_parent_after(clk
, clk
->new_parent
, old_parent
);
1495 if (!skip_set_rate
&& clk
->ops
->set_rate
)
1496 clk
->ops
->set_rate(clk
->hw
, clk
->new_rate
, best_parent_rate
);
1498 clk
->rate
= clk_recalc(clk
, best_parent_rate
);
1500 if (clk
->notifier_count
&& old_rate
!= clk
->rate
)
1501 __clk_notify(clk
, POST_RATE_CHANGE
, old_rate
, clk
->rate
);
1503 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1504 /* Skip children who will be reparented to another clock */
1505 if (child
->new_parent
&& child
->new_parent
!= clk
)
1507 clk_change_rate(child
);
1510 /* handle the new child who might not be in clk->children yet */
1512 clk_change_rate(clk
->new_child
);
1516 * clk_set_rate - specify a new rate for clk
1517 * @clk: the clk whose rate is being changed
1518 * @rate: the new rate for clk
1520 * In the simplest case clk_set_rate will only adjust the rate of clk.
1522 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1523 * propagate up to clk's parent; whether or not this happens depends on the
1524 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1525 * after calling .round_rate then upstream parent propagation is ignored. If
1526 * *parent_rate comes back with a new rate for clk's parent then we propagate
1527 * up to clk's parent and set its rate. Upward propagation will continue
1528 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1529 * .round_rate stops requesting changes to clk's parent_rate.
1531 * Rate changes are accomplished via tree traversal that also recalculates the
1532 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1534 * Returns 0 on success, -EERROR otherwise.
1536 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
1538 struct clk
*top
, *fail_clk
;
1544 /* prevent racing with updates to the clock topology */
1547 /* bail early if nothing to do */
1548 if (rate
== clk_get_rate(clk
))
1551 if ((clk
->flags
& CLK_SET_RATE_GATE
) && clk
->prepare_count
) {
1556 /* calculate new rates and get the topmost changed clock */
1557 top
= clk_calc_new_rates(clk
, rate
);
1563 /* notify that we are about to change rates */
1564 fail_clk
= clk_propagate_rate_change(top
, PRE_RATE_CHANGE
);
1566 pr_debug("%s: failed to set %s rate\n", __func__
,
1568 clk_propagate_rate_change(top
, ABORT_RATE_CHANGE
);
1573 /* change the rates */
1574 clk_change_rate(top
);
1577 clk_prepare_unlock();
1581 EXPORT_SYMBOL_GPL(clk_set_rate
);
1584 * clk_get_parent - return the parent of a clk
1585 * @clk: the clk whose parent gets returned
1587 * Simply returns clk->parent. Returns NULL if clk is NULL.
1589 struct clk
*clk_get_parent(struct clk
*clk
)
1594 parent
= __clk_get_parent(clk
);
1595 clk_prepare_unlock();
1599 EXPORT_SYMBOL_GPL(clk_get_parent
);
1602 * .get_parent is mandatory for clocks with multiple possible parents. It is
1603 * optional for single-parent clocks. Always call .get_parent if it is
1604 * available and WARN if it is missing for multi-parent clocks.
1606 * For single-parent clocks without .get_parent, first check to see if the
1607 * .parents array exists, and if so use it to avoid an expensive tree
1608 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1610 static struct clk
*__clk_init_parent(struct clk
*clk
)
1612 struct clk
*ret
= NULL
;
1615 /* handle the trivial cases */
1617 if (!clk
->num_parents
)
1620 if (clk
->num_parents
== 1) {
1621 if (IS_ERR_OR_NULL(clk
->parent
))
1622 ret
= clk
->parent
= __clk_lookup(clk
->parent_names
[0]);
1627 if (!clk
->ops
->get_parent
) {
1628 WARN(!clk
->ops
->get_parent
,
1629 "%s: multi-parent clocks must implement .get_parent\n",
1635 * Do our best to cache parent clocks in clk->parents. This prevents
1636 * unnecessary and expensive calls to __clk_lookup. We don't set
1637 * clk->parent here; that is done by the calling function
1640 index
= clk
->ops
->get_parent(clk
->hw
);
1644 kcalloc(clk
->num_parents
, sizeof(struct clk
*),
1647 ret
= clk_get_parent_by_index(clk
, index
);
1653 void __clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1655 clk_reparent(clk
, new_parent
);
1656 __clk_recalc_accuracies(clk
);
1657 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1661 * clk_set_parent - switch the parent of a mux clk
1662 * @clk: the mux clk whose input we are switching
1663 * @parent: the new input to clk
1665 * Re-parent clk to use parent as its new input source. If clk is in
1666 * prepared state, the clk will get enabled for the duration of this call. If
1667 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1668 * that, the reparenting is glitchy in hardware, etc), use the
1669 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1671 * After successfully changing clk's parent clk_set_parent will update the
1672 * clk topology, sysfs topology and propagate rate recalculation via
1673 * __clk_recalc_rates.
1675 * Returns 0 on success, -EERROR otherwise.
1677 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
1681 unsigned long p_rate
= 0;
1686 /* verify ops for for multi-parent clks */
1687 if ((clk
->num_parents
> 1) && (!clk
->ops
->set_parent
))
1690 /* prevent racing with updates to the clock topology */
1693 if (clk
->parent
== parent
)
1696 /* check that we are allowed to re-parent if the clock is in use */
1697 if ((clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1702 /* try finding the new parent index */
1704 p_index
= clk_fetch_parent_index(clk
, parent
);
1705 p_rate
= parent
->rate
;
1707 pr_debug("%s: clk %s can not be parent of clk %s\n",
1708 __func__
, parent
->name
, clk
->name
);
1714 /* propagate PRE_RATE_CHANGE notifications */
1715 ret
= __clk_speculate_rates(clk
, p_rate
);
1717 /* abort if a driver objects */
1718 if (ret
& NOTIFY_STOP_MASK
)
1721 /* do the re-parent */
1722 ret
= __clk_set_parent(clk
, parent
, p_index
);
1724 /* propagate rate an accuracy recalculation accordingly */
1726 __clk_recalc_rates(clk
, ABORT_RATE_CHANGE
);
1728 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1729 __clk_recalc_accuracies(clk
);
1733 clk_prepare_unlock();
1737 EXPORT_SYMBOL_GPL(clk_set_parent
);
1740 * __clk_init - initialize the data structures in a struct clk
1741 * @dev: device initializing this clk, placeholder for now
1742 * @clk: clk being initialized
1744 * Initializes the lists in struct clk, queries the hardware for the
1745 * parent and rate and sets them both.
1747 int __clk_init(struct device
*dev
, struct clk
*clk
)
1751 struct hlist_node
*tmp2
;
1758 /* check to see if a clock with this name is already registered */
1759 if (__clk_lookup(clk
->name
)) {
1760 pr_debug("%s: clk %s already initialized\n",
1761 __func__
, clk
->name
);
1766 /* check that clk_ops are sane. See Documentation/clk.txt */
1767 if (clk
->ops
->set_rate
&&
1768 !((clk
->ops
->round_rate
|| clk
->ops
->determine_rate
) &&
1769 clk
->ops
->recalc_rate
)) {
1770 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1771 __func__
, clk
->name
);
1776 if (clk
->ops
->set_parent
&& !clk
->ops
->get_parent
) {
1777 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1778 __func__
, clk
->name
);
1783 if (clk
->ops
->set_rate_and_parent
&&
1784 !(clk
->ops
->set_parent
&& clk
->ops
->set_rate
)) {
1785 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
1786 __func__
, clk
->name
);
1791 /* throw a WARN if any entries in parent_names are NULL */
1792 for (i
= 0; i
< clk
->num_parents
; i
++)
1793 WARN(!clk
->parent_names
[i
],
1794 "%s: invalid NULL in %s's .parent_names\n",
1795 __func__
, clk
->name
);
1798 * Allocate an array of struct clk *'s to avoid unnecessary string
1799 * look-ups of clk's possible parents. This can fail for clocks passed
1800 * in to clk_init during early boot; thus any access to clk->parents[]
1801 * must always check for a NULL pointer and try to populate it if
1804 * If clk->parents is not NULL we skip this entire block. This allows
1805 * for clock drivers to statically initialize clk->parents.
1807 if (clk
->num_parents
> 1 && !clk
->parents
) {
1808 clk
->parents
= kcalloc(clk
->num_parents
, sizeof(struct clk
*),
1811 * __clk_lookup returns NULL for parents that have not been
1812 * clk_init'd; thus any access to clk->parents[] must check
1813 * for a NULL pointer. We can always perform lazy lookups for
1814 * missing parents later on.
1817 for (i
= 0; i
< clk
->num_parents
; i
++)
1819 __clk_lookup(clk
->parent_names
[i
]);
1822 clk
->parent
= __clk_init_parent(clk
);
1825 * Populate clk->parent if parent has already been __clk_init'd. If
1826 * parent has not yet been __clk_init'd then place clk in the orphan
1827 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1830 * Every time a new clk is clk_init'd then we walk the list of orphan
1831 * clocks and re-parent any that are children of the clock currently
1835 hlist_add_head(&clk
->child_node
,
1836 &clk
->parent
->children
);
1837 else if (clk
->flags
& CLK_IS_ROOT
)
1838 hlist_add_head(&clk
->child_node
, &clk_root_list
);
1840 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1843 * Set clk's accuracy. The preferred method is to use
1844 * .recalc_accuracy. For simple clocks and lazy developers the default
1845 * fallback is to use the parent's accuracy. If a clock doesn't have a
1846 * parent (or is orphaned) then accuracy is set to zero (perfect
1849 if (clk
->ops
->recalc_accuracy
)
1850 clk
->accuracy
= clk
->ops
->recalc_accuracy(clk
->hw
,
1851 __clk_get_accuracy(clk
->parent
));
1852 else if (clk
->parent
)
1853 clk
->accuracy
= clk
->parent
->accuracy
;
1858 * Set clk's rate. The preferred method is to use .recalc_rate. For
1859 * simple clocks and lazy developers the default fallback is to use the
1860 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1861 * then rate is set to zero.
1863 if (clk
->ops
->recalc_rate
)
1864 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
,
1865 __clk_get_rate(clk
->parent
));
1866 else if (clk
->parent
)
1867 clk
->rate
= clk
->parent
->rate
;
1871 clk_debug_register(clk
);
1873 * walk the list of orphan clocks and reparent any that are children of
1876 hlist_for_each_entry_safe(orphan
, tmp2
, &clk_orphan_list
, child_node
) {
1877 if (orphan
->num_parents
&& orphan
->ops
->get_parent
) {
1878 i
= orphan
->ops
->get_parent(orphan
->hw
);
1879 if (!strcmp(clk
->name
, orphan
->parent_names
[i
]))
1880 __clk_reparent(orphan
, clk
);
1884 for (i
= 0; i
< orphan
->num_parents
; i
++)
1885 if (!strcmp(clk
->name
, orphan
->parent_names
[i
])) {
1886 __clk_reparent(orphan
, clk
);
1892 * optional platform-specific magic
1894 * The .init callback is not used by any of the basic clock types, but
1895 * exists for weird hardware that must perform initialization magic.
1896 * Please consider other ways of solving initialization problems before
1897 * using this callback, as its use is discouraged.
1900 clk
->ops
->init(clk
->hw
);
1902 kref_init(&clk
->ref
);
1904 clk_prepare_unlock();
1910 * __clk_register - register a clock and return a cookie.
1912 * Same as clk_register, except that the .clk field inside hw shall point to a
1913 * preallocated (generally statically allocated) struct clk. None of the fields
1914 * of the struct clk need to be initialized.
1916 * The data pointed to by .init and .clk field shall NOT be marked as init
1919 * __clk_register is only exposed via clk-private.h and is intended for use with
1920 * very large numbers of clocks that need to be statically initialized. It is
1921 * a layering violation to include clk-private.h from any code which implements
1922 * a clock's .ops; as such any statically initialized clock data MUST be in a
1923 * separate C file from the logic that implements its operations. Returns 0
1924 * on success, otherwise an error code.
1926 struct clk
*__clk_register(struct device
*dev
, struct clk_hw
*hw
)
1932 clk
->name
= hw
->init
->name
;
1933 clk
->ops
= hw
->init
->ops
;
1935 clk
->flags
= hw
->init
->flags
;
1936 clk
->parent_names
= hw
->init
->parent_names
;
1937 clk
->num_parents
= hw
->init
->num_parents
;
1938 if (dev
&& dev
->driver
)
1939 clk
->owner
= dev
->driver
->owner
;
1943 ret
= __clk_init(dev
, clk
);
1945 return ERR_PTR(ret
);
1949 EXPORT_SYMBOL_GPL(__clk_register
);
1952 * clk_register - allocate a new clock, register it and return an opaque cookie
1953 * @dev: device that is registering this clock
1954 * @hw: link to hardware-specific clock data
1956 * clk_register is the primary interface for populating the clock tree with new
1957 * clock nodes. It returns a pointer to the newly allocated struct clk which
1958 * cannot be dereferenced by driver code but may be used in conjuction with the
1959 * rest of the clock API. In the event of an error clk_register will return an
1960 * error code; drivers must test for an error code after calling clk_register.
1962 struct clk
*clk_register(struct device
*dev
, struct clk_hw
*hw
)
1967 clk
= kzalloc(sizeof(*clk
), GFP_KERNEL
);
1969 pr_err("%s: could not allocate clk\n", __func__
);
1974 clk
->name
= kstrdup(hw
->init
->name
, GFP_KERNEL
);
1976 pr_err("%s: could not allocate clk->name\n", __func__
);
1980 clk
->ops
= hw
->init
->ops
;
1981 if (dev
&& dev
->driver
)
1982 clk
->owner
= dev
->driver
->owner
;
1984 clk
->flags
= hw
->init
->flags
;
1985 clk
->num_parents
= hw
->init
->num_parents
;
1988 /* allocate local copy in case parent_names is __initdata */
1989 clk
->parent_names
= kcalloc(clk
->num_parents
, sizeof(char *),
1992 if (!clk
->parent_names
) {
1993 pr_err("%s: could not allocate clk->parent_names\n", __func__
);
1995 goto fail_parent_names
;
1999 /* copy each string name in case parent_names is __initdata */
2000 for (i
= 0; i
< clk
->num_parents
; i
++) {
2001 clk
->parent_names
[i
] = kstrdup(hw
->init
->parent_names
[i
],
2003 if (!clk
->parent_names
[i
]) {
2004 pr_err("%s: could not copy parent_names\n", __func__
);
2006 goto fail_parent_names_copy
;
2010 ret
= __clk_init(dev
, clk
);
2014 fail_parent_names_copy
:
2016 kfree(clk
->parent_names
[i
]);
2017 kfree(clk
->parent_names
);
2023 return ERR_PTR(ret
);
2025 EXPORT_SYMBOL_GPL(clk_register
);
2028 * Free memory allocated for a clock.
2029 * Caller must hold prepare_lock.
2031 static void __clk_release(struct kref
*ref
)
2033 struct clk
*clk
= container_of(ref
, struct clk
, ref
);
2034 int i
= clk
->num_parents
;
2036 kfree(clk
->parents
);
2038 kfree(clk
->parent_names
[i
]);
2040 kfree(clk
->parent_names
);
2046 * Empty clk_ops for unregistered clocks. These are used temporarily
2047 * after clk_unregister() was called on a clock and until last clock
2048 * consumer calls clk_put() and the struct clk object is freed.
2050 static int clk_nodrv_prepare_enable(struct clk_hw
*hw
)
2055 static void clk_nodrv_disable_unprepare(struct clk_hw
*hw
)
2060 static int clk_nodrv_set_rate(struct clk_hw
*hw
, unsigned long rate
,
2061 unsigned long parent_rate
)
2066 static int clk_nodrv_set_parent(struct clk_hw
*hw
, u8 index
)
2071 static const struct clk_ops clk_nodrv_ops
= {
2072 .enable
= clk_nodrv_prepare_enable
,
2073 .disable
= clk_nodrv_disable_unprepare
,
2074 .prepare
= clk_nodrv_prepare_enable
,
2075 .unprepare
= clk_nodrv_disable_unprepare
,
2076 .set_rate
= clk_nodrv_set_rate
,
2077 .set_parent
= clk_nodrv_set_parent
,
2081 * clk_unregister - unregister a currently registered clock
2082 * @clk: clock to unregister
2084 void clk_unregister(struct clk
*clk
)
2086 unsigned long flags
;
2088 if (!clk
|| WARN_ON_ONCE(IS_ERR(clk
)))
2093 if (clk
->ops
== &clk_nodrv_ops
) {
2094 pr_err("%s: unregistered clock: %s\n", __func__
, clk
->name
);
2098 * Assign empty clock ops for consumers that might still hold
2099 * a reference to this clock.
2101 flags
= clk_enable_lock();
2102 clk
->ops
= &clk_nodrv_ops
;
2103 clk_enable_unlock(flags
);
2105 if (!hlist_empty(&clk
->children
)) {
2107 struct hlist_node
*t
;
2109 /* Reparent all children to the orphan list. */
2110 hlist_for_each_entry_safe(child
, t
, &clk
->children
, child_node
)
2111 clk_set_parent(child
, NULL
);
2114 clk_debug_unregister(clk
);
2116 hlist_del_init(&clk
->child_node
);
2118 if (clk
->prepare_count
)
2119 pr_warn("%s: unregistering prepared clock: %s\n",
2120 __func__
, clk
->name
);
2122 kref_put(&clk
->ref
, __clk_release
);
2124 clk_prepare_unlock();
2126 EXPORT_SYMBOL_GPL(clk_unregister
);
2128 static void devm_clk_release(struct device
*dev
, void *res
)
2130 clk_unregister(*(struct clk
**)res
);
2134 * devm_clk_register - resource managed clk_register()
2135 * @dev: device that is registering this clock
2136 * @hw: link to hardware-specific clock data
2138 * Managed clk_register(). Clocks returned from this function are
2139 * automatically clk_unregister()ed on driver detach. See clk_register() for
2142 struct clk
*devm_clk_register(struct device
*dev
, struct clk_hw
*hw
)
2147 clkp
= devres_alloc(devm_clk_release
, sizeof(*clkp
), GFP_KERNEL
);
2149 return ERR_PTR(-ENOMEM
);
2151 clk
= clk_register(dev
, hw
);
2154 devres_add(dev
, clkp
);
2161 EXPORT_SYMBOL_GPL(devm_clk_register
);
2163 static int devm_clk_match(struct device
*dev
, void *res
, void *data
)
2165 struct clk
*c
= res
;
2172 * devm_clk_unregister - resource managed clk_unregister()
2173 * @clk: clock to unregister
2175 * Deallocate a clock allocated with devm_clk_register(). Normally
2176 * this function will not need to be called and the resource management
2177 * code will ensure that the resource is freed.
2179 void devm_clk_unregister(struct device
*dev
, struct clk
*clk
)
2181 WARN_ON(devres_release(dev
, devm_clk_release
, devm_clk_match
, clk
));
2183 EXPORT_SYMBOL_GPL(devm_clk_unregister
);
2188 int __clk_get(struct clk
*clk
)
2191 if (!try_module_get(clk
->owner
))
2194 kref_get(&clk
->ref
);
2199 void __clk_put(struct clk
*clk
)
2201 if (!clk
|| WARN_ON_ONCE(IS_ERR(clk
)))
2205 kref_put(&clk
->ref
, __clk_release
);
2206 clk_prepare_unlock();
2208 module_put(clk
->owner
);
2211 /*** clk rate change notifiers ***/
2214 * clk_notifier_register - add a clk rate change notifier
2215 * @clk: struct clk * to watch
2216 * @nb: struct notifier_block * with callback info
2218 * Request notification when clk's rate changes. This uses an SRCU
2219 * notifier because we want it to block and notifier unregistrations are
2220 * uncommon. The callbacks associated with the notifier must not
2221 * re-enter into the clk framework by calling any top-level clk APIs;
2222 * this will cause a nested prepare_lock mutex.
2224 * In all notification cases cases (pre, post and abort rate change) the
2225 * original clock rate is passed to the callback via struct
2226 * clk_notifier_data.old_rate and the new frequency is passed via struct
2227 * clk_notifier_data.new_rate.
2229 * clk_notifier_register() must be called from non-atomic context.
2230 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2231 * allocation failure; otherwise, passes along the return value of
2232 * srcu_notifier_chain_register().
2234 int clk_notifier_register(struct clk
*clk
, struct notifier_block
*nb
)
2236 struct clk_notifier
*cn
;
2244 /* search the list of notifiers for this clk */
2245 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2249 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2250 if (cn
->clk
!= clk
) {
2251 cn
= kzalloc(sizeof(struct clk_notifier
), GFP_KERNEL
);
2256 srcu_init_notifier_head(&cn
->notifier_head
);
2258 list_add(&cn
->node
, &clk_notifier_list
);
2261 ret
= srcu_notifier_chain_register(&cn
->notifier_head
, nb
);
2263 clk
->notifier_count
++;
2266 clk_prepare_unlock();
2270 EXPORT_SYMBOL_GPL(clk_notifier_register
);
2273 * clk_notifier_unregister - remove a clk rate change notifier
2274 * @clk: struct clk *
2275 * @nb: struct notifier_block * with callback info
2277 * Request no further notification for changes to 'clk' and frees memory
2278 * allocated in clk_notifier_register.
2280 * Returns -EINVAL if called with null arguments; otherwise, passes
2281 * along the return value of srcu_notifier_chain_unregister().
2283 int clk_notifier_unregister(struct clk
*clk
, struct notifier_block
*nb
)
2285 struct clk_notifier
*cn
= NULL
;
2293 list_for_each_entry(cn
, &clk_notifier_list
, node
)
2297 if (cn
->clk
== clk
) {
2298 ret
= srcu_notifier_chain_unregister(&cn
->notifier_head
, nb
);
2300 clk
->notifier_count
--;
2302 /* XXX the notifier code should handle this better */
2303 if (!cn
->notifier_head
.head
) {
2304 srcu_cleanup_notifier_head(&cn
->notifier_head
);
2305 list_del(&cn
->node
);
2313 clk_prepare_unlock();
2317 EXPORT_SYMBOL_GPL(clk_notifier_unregister
);
2321 * struct of_clk_provider - Clock provider registration structure
2322 * @link: Entry in global list of clock providers
2323 * @node: Pointer to device tree node of clock provider
2324 * @get: Get clock callback. Returns NULL or a struct clk for the
2325 * given clock specifier
2326 * @data: context pointer to be passed into @get callback
2328 struct of_clk_provider
{
2329 struct list_head link
;
2331 struct device_node
*node
;
2332 struct clk
*(*get
)(struct of_phandle_args
*clkspec
, void *data
);
2336 static const struct of_device_id __clk_of_table_sentinel
2337 __used
__section(__clk_of_table_end
);
2339 static LIST_HEAD(of_clk_providers
);
2340 static DEFINE_MUTEX(of_clk_mutex
);
2342 /* of_clk_provider list locking helpers */
2343 void of_clk_lock(void)
2345 mutex_lock(&of_clk_mutex
);
2348 void of_clk_unlock(void)
2350 mutex_unlock(&of_clk_mutex
);
2353 struct clk
*of_clk_src_simple_get(struct of_phandle_args
*clkspec
,
2358 EXPORT_SYMBOL_GPL(of_clk_src_simple_get
);
2360 struct clk
*of_clk_src_onecell_get(struct of_phandle_args
*clkspec
, void *data
)
2362 struct clk_onecell_data
*clk_data
= data
;
2363 unsigned int idx
= clkspec
->args
[0];
2365 if (idx
>= clk_data
->clk_num
) {
2366 pr_err("%s: invalid clock index %d\n", __func__
, idx
);
2367 return ERR_PTR(-EINVAL
);
2370 return clk_data
->clks
[idx
];
2372 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get
);
2375 * of_clk_add_provider() - Register a clock provider for a node
2376 * @np: Device node pointer associated with clock provider
2377 * @clk_src_get: callback for decoding clock
2378 * @data: context pointer for @clk_src_get callback.
2380 int of_clk_add_provider(struct device_node
*np
,
2381 struct clk
*(*clk_src_get
)(struct of_phandle_args
*clkspec
,
2385 struct of_clk_provider
*cp
;
2388 cp
= kzalloc(sizeof(struct of_clk_provider
), GFP_KERNEL
);
2392 cp
->node
= of_node_get(np
);
2394 cp
->get
= clk_src_get
;
2396 mutex_lock(&of_clk_mutex
);
2397 list_add(&cp
->link
, &of_clk_providers
);
2398 mutex_unlock(&of_clk_mutex
);
2399 pr_debug("Added clock from %s\n", np
->full_name
);
2401 ret
= of_clk_set_defaults(np
, true);
2403 of_clk_del_provider(np
);
2407 EXPORT_SYMBOL_GPL(of_clk_add_provider
);
2410 * of_clk_del_provider() - Remove a previously registered clock provider
2411 * @np: Device node pointer associated with clock provider
2413 void of_clk_del_provider(struct device_node
*np
)
2415 struct of_clk_provider
*cp
;
2417 mutex_lock(&of_clk_mutex
);
2418 list_for_each_entry(cp
, &of_clk_providers
, link
) {
2419 if (cp
->node
== np
) {
2420 list_del(&cp
->link
);
2421 of_node_put(cp
->node
);
2426 mutex_unlock(&of_clk_mutex
);
2428 EXPORT_SYMBOL_GPL(of_clk_del_provider
);
2430 struct clk
*__of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2432 struct of_clk_provider
*provider
;
2433 struct clk
*clk
= ERR_PTR(-EPROBE_DEFER
);
2435 /* Check if we have such a provider in our array */
2436 list_for_each_entry(provider
, &of_clk_providers
, link
) {
2437 if (provider
->node
== clkspec
->np
)
2438 clk
= provider
->get(clkspec
, provider
->data
);
2446 struct clk
*of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2450 mutex_lock(&of_clk_mutex
);
2451 clk
= __of_clk_get_from_provider(clkspec
);
2452 mutex_unlock(&of_clk_mutex
);
2457 int of_clk_get_parent_count(struct device_node
*np
)
2459 return of_count_phandle_with_args(np
, "clocks", "#clock-cells");
2461 EXPORT_SYMBOL_GPL(of_clk_get_parent_count
);
2463 const char *of_clk_get_parent_name(struct device_node
*np
, int index
)
2465 struct of_phandle_args clkspec
;
2466 struct property
*prop
;
2467 const char *clk_name
;
2476 rc
= of_parse_phandle_with_args(np
, "clocks", "#clock-cells", index
,
2481 index
= clkspec
.args_count
? clkspec
.args
[0] : 0;
2484 /* if there is an indices property, use it to transfer the index
2485 * specified into an array offset for the clock-output-names property.
2487 of_property_for_each_u32(clkspec
.np
, "clock-indices", prop
, vp
, pv
) {
2495 if (of_property_read_string_index(clkspec
.np
, "clock-output-names",
2498 clk_name
= clkspec
.np
->name
;
2500 of_node_put(clkspec
.np
);
2503 EXPORT_SYMBOL_GPL(of_clk_get_parent_name
);
2505 struct clock_provider
{
2506 of_clk_init_cb_t clk_init_cb
;
2507 struct device_node
*np
;
2508 struct list_head node
;
2511 static LIST_HEAD(clk_provider_list
);
2514 * This function looks for a parent clock. If there is one, then it
2515 * checks that the provider for this parent clock was initialized, in
2516 * this case the parent clock will be ready.
2518 static int parent_ready(struct device_node
*np
)
2523 struct clk
*clk
= of_clk_get(np
, i
);
2525 /* this parent is ready we can check the next one */
2532 /* at least one parent is not ready, we exit now */
2533 if (PTR_ERR(clk
) == -EPROBE_DEFER
)
2537 * Here we make assumption that the device tree is
2538 * written correctly. So an error means that there is
2539 * no more parent. As we didn't exit yet, then the
2540 * previous parent are ready. If there is no clock
2541 * parent, no need to wait for them, then we can
2542 * consider their absence as being ready
2549 * of_clk_init() - Scan and init clock providers from the DT
2550 * @matches: array of compatible values and init functions for providers.
2552 * This function scans the device tree for matching clock providers
2553 * and calls their initialization functions. It also does it by trying
2554 * to follow the dependencies.
2556 void __init
of_clk_init(const struct of_device_id
*matches
)
2558 const struct of_device_id
*match
;
2559 struct device_node
*np
;
2560 struct clock_provider
*clk_provider
, *next
;
2565 matches
= &__clk_of_table
;
2567 /* First prepare the list of the clocks providers */
2568 for_each_matching_node_and_match(np
, matches
, &match
) {
2569 struct clock_provider
*parent
=
2570 kzalloc(sizeof(struct clock_provider
), GFP_KERNEL
);
2572 parent
->clk_init_cb
= match
->data
;
2574 list_add_tail(&parent
->node
, &clk_provider_list
);
2577 while (!list_empty(&clk_provider_list
)) {
2578 is_init_done
= false;
2579 list_for_each_entry_safe(clk_provider
, next
,
2580 &clk_provider_list
, node
) {
2581 if (force
|| parent_ready(clk_provider
->np
)) {
2583 clk_provider
->clk_init_cb(clk_provider
->np
);
2584 of_clk_set_defaults(clk_provider
->np
, true);
2586 list_del(&clk_provider
->node
);
2587 kfree(clk_provider
);
2588 is_init_done
= true;
2593 * We didn't manage to initialize any of the
2594 * remaining providers during the last loop, so now we
2595 * initialize all the remaining ones unconditionally
2596 * in case the clock parent was not mandatory