2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
12 #include <linux/clk-private.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock.h>
16 #include <linux/err.h>
17 #include <linux/list.h>
18 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
24 static DEFINE_SPINLOCK(enable_lock
);
25 static DEFINE_MUTEX(prepare_lock
);
27 static struct task_struct
*prepare_owner
;
28 static struct task_struct
*enable_owner
;
30 static int prepare_refcnt
;
31 static int enable_refcnt
;
33 static HLIST_HEAD(clk_root_list
);
34 static HLIST_HEAD(clk_orphan_list
);
35 static LIST_HEAD(clk_notifier_list
);
38 static void clk_prepare_lock(void)
40 if (!mutex_trylock(&prepare_lock
)) {
41 if (prepare_owner
== current
) {
45 mutex_lock(&prepare_lock
);
47 WARN_ON_ONCE(prepare_owner
!= NULL
);
48 WARN_ON_ONCE(prepare_refcnt
!= 0);
49 prepare_owner
= current
;
53 static void clk_prepare_unlock(void)
55 WARN_ON_ONCE(prepare_owner
!= current
);
56 WARN_ON_ONCE(prepare_refcnt
== 0);
61 mutex_unlock(&prepare_lock
);
64 static unsigned long clk_enable_lock(void)
68 if (!spin_trylock_irqsave(&enable_lock
, flags
)) {
69 if (enable_owner
== current
) {
73 spin_lock_irqsave(&enable_lock
, flags
);
75 WARN_ON_ONCE(enable_owner
!= NULL
);
76 WARN_ON_ONCE(enable_refcnt
!= 0);
77 enable_owner
= current
;
82 static void clk_enable_unlock(unsigned long flags
)
84 WARN_ON_ONCE(enable_owner
!= current
);
85 WARN_ON_ONCE(enable_refcnt
== 0);
90 spin_unlock_irqrestore(&enable_lock
, flags
);
93 /*** debugfs support ***/
95 #ifdef CONFIG_COMMON_CLK_DEBUG
96 #include <linux/debugfs.h>
98 static struct dentry
*rootdir
;
99 static struct dentry
*orphandir
;
100 static int inited
= 0;
102 static void clk_summary_show_one(struct seq_file
*s
, struct clk
*c
, int level
)
107 seq_printf(s
, "%*s%-*s %-11d %-12d %-10lu",
109 30 - level
* 3, c
->name
,
110 c
->enable_count
, c
->prepare_count
, c
->rate
);
114 static void clk_summary_show_subtree(struct seq_file
*s
, struct clk
*c
,
122 clk_summary_show_one(s
, c
, level
);
124 hlist_for_each_entry(child
, &c
->children
, child_node
)
125 clk_summary_show_subtree(s
, child
, level
+ 1);
128 static int clk_summary_show(struct seq_file
*s
, void *data
)
132 seq_printf(s
, " clock enable_cnt prepare_cnt rate\n");
133 seq_printf(s
, "---------------------------------------------------------------------\n");
137 hlist_for_each_entry(c
, &clk_root_list
, child_node
)
138 clk_summary_show_subtree(s
, c
, 0);
140 hlist_for_each_entry(c
, &clk_orphan_list
, child_node
)
141 clk_summary_show_subtree(s
, c
, 0);
143 clk_prepare_unlock();
149 static int clk_summary_open(struct inode
*inode
, struct file
*file
)
151 return single_open(file
, clk_summary_show
, inode
->i_private
);
154 static const struct file_operations clk_summary_fops
= {
155 .open
= clk_summary_open
,
158 .release
= single_release
,
161 static void clk_dump_one(struct seq_file
*s
, struct clk
*c
, int level
)
166 seq_printf(s
, "\"%s\": { ", c
->name
);
167 seq_printf(s
, "\"enable_count\": %d,", c
->enable_count
);
168 seq_printf(s
, "\"prepare_count\": %d,", c
->prepare_count
);
169 seq_printf(s
, "\"rate\": %lu", c
->rate
);
172 static void clk_dump_subtree(struct seq_file
*s
, struct clk
*c
, int level
)
179 clk_dump_one(s
, c
, level
);
181 hlist_for_each_entry(child
, &c
->children
, child_node
) {
183 clk_dump_subtree(s
, child
, level
+ 1);
189 static int clk_dump(struct seq_file
*s
, void *data
)
192 bool first_node
= true;
198 hlist_for_each_entry(c
, &clk_root_list
, child_node
) {
202 clk_dump_subtree(s
, c
, 0);
205 hlist_for_each_entry(c
, &clk_orphan_list
, child_node
) {
207 clk_dump_subtree(s
, c
, 0);
210 clk_prepare_unlock();
217 static int clk_dump_open(struct inode
*inode
, struct file
*file
)
219 return single_open(file
, clk_dump
, inode
->i_private
);
222 static const struct file_operations clk_dump_fops
= {
223 .open
= clk_dump_open
,
226 .release
= single_release
,
229 /* caller must hold prepare_lock */
230 static int clk_debug_create_one(struct clk
*clk
, struct dentry
*pdentry
)
235 if (!clk
|| !pdentry
) {
240 d
= debugfs_create_dir(clk
->name
, pdentry
);
246 d
= debugfs_create_u32("clk_rate", S_IRUGO
, clk
->dentry
,
251 d
= debugfs_create_x32("clk_flags", S_IRUGO
, clk
->dentry
,
256 d
= debugfs_create_u32("clk_prepare_count", S_IRUGO
, clk
->dentry
,
257 (u32
*)&clk
->prepare_count
);
261 d
= debugfs_create_u32("clk_enable_count", S_IRUGO
, clk
->dentry
,
262 (u32
*)&clk
->enable_count
);
266 d
= debugfs_create_u32("clk_notifier_count", S_IRUGO
, clk
->dentry
,
267 (u32
*)&clk
->notifier_count
);
275 debugfs_remove(clk
->dentry
);
280 /* caller must hold prepare_lock */
281 static int clk_debug_create_subtree(struct clk
*clk
, struct dentry
*pdentry
)
286 if (!clk
|| !pdentry
)
289 ret
= clk_debug_create_one(clk
, pdentry
);
294 hlist_for_each_entry(child
, &clk
->children
, child_node
)
295 clk_debug_create_subtree(child
, clk
->dentry
);
303 * clk_debug_register - add a clk node to the debugfs clk tree
304 * @clk: the clk being added to the debugfs clk tree
306 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
307 * initialized. Otherwise it bails out early since the debugfs clk tree
308 * will be created lazily by clk_debug_init as part of a late_initcall.
310 * Caller must hold prepare_lock. Only clk_init calls this function (so
311 * far) so this is taken care.
313 static int clk_debug_register(struct clk
*clk
)
316 struct dentry
*pdentry
;
322 parent
= clk
->parent
;
325 * Check to see if a clk is a root clk. Also check that it is
326 * safe to add this clk to debugfs
329 if (clk
->flags
& CLK_IS_ROOT
)
335 pdentry
= parent
->dentry
;
339 ret
= clk_debug_create_subtree(clk
, pdentry
);
346 * clk_debug_reparent - reparent clk node in the debugfs clk tree
347 * @clk: the clk being reparented
348 * @new_parent: the new clk parent, may be NULL
350 * Rename clk entry in the debugfs clk tree if debugfs has been
351 * initialized. Otherwise it bails out early since the debugfs clk tree
352 * will be created lazily by clk_debug_init as part of a late_initcall.
354 * Caller must hold prepare_lock.
356 static void clk_debug_reparent(struct clk
*clk
, struct clk
*new_parent
)
359 struct dentry
*new_parent_d
;
365 new_parent_d
= new_parent
->dentry
;
367 new_parent_d
= orphandir
;
369 d
= debugfs_rename(clk
->dentry
->d_parent
, clk
->dentry
,
370 new_parent_d
, clk
->name
);
374 pr_debug("%s: failed to rename debugfs entry for %s\n",
375 __func__
, clk
->name
);
379 * clk_debug_init - lazily create the debugfs clk tree visualization
381 * clks are often initialized very early during boot before memory can
382 * be dynamically allocated and well before debugfs is setup.
383 * clk_debug_init walks the clk tree hierarchy while holding
384 * prepare_lock and creates the topology as part of a late_initcall,
385 * thus insuring that clks initialized very early will still be
386 * represented in the debugfs clk tree. This function should only be
387 * called once at boot-time, and all other clks added dynamically will
388 * be done so with clk_debug_register.
390 static int __init
clk_debug_init(void)
395 rootdir
= debugfs_create_dir("clk", NULL
);
400 d
= debugfs_create_file("clk_summary", S_IRUGO
, rootdir
, NULL
,
405 d
= debugfs_create_file("clk_dump", S_IRUGO
, rootdir
, NULL
,
410 orphandir
= debugfs_create_dir("orphans", rootdir
);
417 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
418 clk_debug_create_subtree(clk
, rootdir
);
420 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
421 clk_debug_create_subtree(clk
, orphandir
);
425 clk_prepare_unlock();
429 late_initcall(clk_debug_init
);
431 static inline int clk_debug_register(struct clk
*clk
) { return 0; }
432 static inline void clk_debug_reparent(struct clk
*clk
, struct clk
*new_parent
)
437 /* caller must hold prepare_lock */
438 static void clk_unprepare_unused_subtree(struct clk
*clk
)
445 hlist_for_each_entry(child
, &clk
->children
, child_node
)
446 clk_unprepare_unused_subtree(child
);
448 if (clk
->prepare_count
)
451 if (clk
->flags
& CLK_IGNORE_UNUSED
)
454 if (__clk_is_prepared(clk
)) {
455 if (clk
->ops
->unprepare_unused
)
456 clk
->ops
->unprepare_unused(clk
->hw
);
457 else if (clk
->ops
->unprepare
)
458 clk
->ops
->unprepare(clk
->hw
);
461 EXPORT_SYMBOL_GPL(__clk_get_flags
);
463 /* caller must hold prepare_lock */
464 static void clk_disable_unused_subtree(struct clk
*clk
)
472 hlist_for_each_entry(child
, &clk
->children
, child_node
)
473 clk_disable_unused_subtree(child
);
475 flags
= clk_enable_lock();
477 if (clk
->enable_count
)
480 if (clk
->flags
& CLK_IGNORE_UNUSED
)
484 * some gate clocks have special needs during the disable-unused
485 * sequence. call .disable_unused if available, otherwise fall
488 if (__clk_is_enabled(clk
)) {
489 if (clk
->ops
->disable_unused
)
490 clk
->ops
->disable_unused(clk
->hw
);
491 else if (clk
->ops
->disable
)
492 clk
->ops
->disable(clk
->hw
);
496 clk_enable_unlock(flags
);
502 static bool clk_ignore_unused
;
503 static int __init
clk_ignore_unused_setup(char *__unused
)
505 clk_ignore_unused
= true;
508 __setup("clk_ignore_unused", clk_ignore_unused_setup
);
510 static int clk_disable_unused(void)
514 if (clk_ignore_unused
) {
515 pr_warn("clk: Not disabling unused clocks\n");
521 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
522 clk_disable_unused_subtree(clk
);
524 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
525 clk_disable_unused_subtree(clk
);
527 hlist_for_each_entry(clk
, &clk_root_list
, child_node
)
528 clk_unprepare_unused_subtree(clk
);
530 hlist_for_each_entry(clk
, &clk_orphan_list
, child_node
)
531 clk_unprepare_unused_subtree(clk
);
533 clk_prepare_unlock();
537 late_initcall(clk_disable_unused
);
539 /*** helper functions ***/
541 const char *__clk_get_name(struct clk
*clk
)
543 return !clk
? NULL
: clk
->name
;
545 EXPORT_SYMBOL_GPL(__clk_get_name
);
547 struct clk_hw
*__clk_get_hw(struct clk
*clk
)
549 return !clk
? NULL
: clk
->hw
;
552 u8
__clk_get_num_parents(struct clk
*clk
)
554 return !clk
? 0 : clk
->num_parents
;
557 struct clk
*__clk_get_parent(struct clk
*clk
)
559 return !clk
? NULL
: clk
->parent
;
562 unsigned int __clk_get_enable_count(struct clk
*clk
)
564 return !clk
? 0 : clk
->enable_count
;
567 unsigned int __clk_get_prepare_count(struct clk
*clk
)
569 return !clk
? 0 : clk
->prepare_count
;
572 unsigned long __clk_get_rate(struct clk
*clk
)
583 if (clk
->flags
& CLK_IS_ROOT
)
593 unsigned long __clk_get_flags(struct clk
*clk
)
595 return !clk
? 0 : clk
->flags
;
598 bool __clk_is_prepared(struct clk
*clk
)
606 * .is_prepared is optional for clocks that can prepare
607 * fall back to software usage counter if it is missing
609 if (!clk
->ops
->is_prepared
) {
610 ret
= clk
->prepare_count
? 1 : 0;
614 ret
= clk
->ops
->is_prepared(clk
->hw
);
619 bool __clk_is_enabled(struct clk
*clk
)
627 * .is_enabled is only mandatory for clocks that gate
628 * fall back to software usage counter if .is_enabled is missing
630 if (!clk
->ops
->is_enabled
) {
631 ret
= clk
->enable_count
? 1 : 0;
635 ret
= clk
->ops
->is_enabled(clk
->hw
);
640 static struct clk
*__clk_lookup_subtree(const char *name
, struct clk
*clk
)
645 if (!strcmp(clk
->name
, name
))
648 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
649 ret
= __clk_lookup_subtree(name
, child
);
657 struct clk
*__clk_lookup(const char *name
)
659 struct clk
*root_clk
;
665 /* search the 'proper' clk tree first */
666 hlist_for_each_entry(root_clk
, &clk_root_list
, child_node
) {
667 ret
= __clk_lookup_subtree(name
, root_clk
);
672 /* if not found, then search the orphan tree */
673 hlist_for_each_entry(root_clk
, &clk_orphan_list
, child_node
) {
674 ret
= __clk_lookup_subtree(name
, root_clk
);
684 void __clk_unprepare(struct clk
*clk
)
689 if (WARN_ON(clk
->prepare_count
== 0))
692 if (--clk
->prepare_count
> 0)
695 WARN_ON(clk
->enable_count
> 0);
697 if (clk
->ops
->unprepare
)
698 clk
->ops
->unprepare(clk
->hw
);
700 __clk_unprepare(clk
->parent
);
704 * clk_unprepare - undo preparation of a clock source
705 * @clk: the clk being unprepare
707 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
708 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
709 * if the operation may sleep. One example is a clk which is accessed over
710 * I2c. In the complex case a clk gate operation may require a fast and a slow
711 * part. It is this reason that clk_unprepare and clk_disable are not mutually
712 * exclusive. In fact clk_disable must be called before clk_unprepare.
714 void clk_unprepare(struct clk
*clk
)
717 __clk_unprepare(clk
);
718 clk_prepare_unlock();
720 EXPORT_SYMBOL_GPL(clk_unprepare
);
722 int __clk_prepare(struct clk
*clk
)
729 if (clk
->prepare_count
== 0) {
730 ret
= __clk_prepare(clk
->parent
);
734 if (clk
->ops
->prepare
) {
735 ret
= clk
->ops
->prepare(clk
->hw
);
737 __clk_unprepare(clk
->parent
);
743 clk
->prepare_count
++;
749 * clk_prepare - prepare a clock source
750 * @clk: the clk being prepared
752 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
753 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
754 * operation may sleep. One example is a clk which is accessed over I2c. In
755 * the complex case a clk ungate operation may require a fast and a slow part.
756 * It is this reason that clk_prepare and clk_enable are not mutually
757 * exclusive. In fact clk_prepare must be called before clk_enable.
758 * Returns 0 on success, -EERROR otherwise.
760 int clk_prepare(struct clk
*clk
)
765 ret
= __clk_prepare(clk
);
766 clk_prepare_unlock();
770 EXPORT_SYMBOL_GPL(clk_prepare
);
772 static void __clk_disable(struct clk
*clk
)
777 if (WARN_ON(IS_ERR(clk
)))
780 if (WARN_ON(clk
->enable_count
== 0))
783 if (--clk
->enable_count
> 0)
786 if (clk
->ops
->disable
)
787 clk
->ops
->disable(clk
->hw
);
789 __clk_disable(clk
->parent
);
793 * clk_disable - gate a clock
794 * @clk: the clk being gated
796 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
797 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
798 * clk if the operation is fast and will never sleep. One example is a
799 * SoC-internal clk which is controlled via simple register writes. In the
800 * complex case a clk gate operation may require a fast and a slow part. It is
801 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
802 * In fact clk_disable must be called before clk_unprepare.
804 void clk_disable(struct clk
*clk
)
808 flags
= clk_enable_lock();
810 clk_enable_unlock(flags
);
812 EXPORT_SYMBOL_GPL(clk_disable
);
814 static int __clk_enable(struct clk
*clk
)
821 if (WARN_ON(clk
->prepare_count
== 0))
824 if (clk
->enable_count
== 0) {
825 ret
= __clk_enable(clk
->parent
);
830 if (clk
->ops
->enable
) {
831 ret
= clk
->ops
->enable(clk
->hw
);
833 __clk_disable(clk
->parent
);
844 * clk_enable - ungate a clock
845 * @clk: the clk being ungated
847 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
848 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
849 * if the operation will never sleep. One example is a SoC-internal clk which
850 * is controlled via simple register writes. In the complex case a clk ungate
851 * operation may require a fast and a slow part. It is this reason that
852 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
853 * must be called before clk_enable. Returns 0 on success, -EERROR
856 int clk_enable(struct clk
*clk
)
861 flags
= clk_enable_lock();
862 ret
= __clk_enable(clk
);
863 clk_enable_unlock(flags
);
867 EXPORT_SYMBOL_GPL(clk_enable
);
870 * __clk_round_rate - round the given rate for a clk
871 * @clk: round the rate of this clock
873 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
875 unsigned long __clk_round_rate(struct clk
*clk
, unsigned long rate
)
877 unsigned long parent_rate
= 0;
882 if (!clk
->ops
->round_rate
) {
883 if (clk
->flags
& CLK_SET_RATE_PARENT
)
884 return __clk_round_rate(clk
->parent
, rate
);
890 parent_rate
= clk
->parent
->rate
;
892 return clk
->ops
->round_rate(clk
->hw
, rate
, &parent_rate
);
896 * clk_round_rate - round the given rate for a clk
897 * @clk: the clk for which we are rounding a rate
898 * @rate: the rate which is to be rounded
900 * Takes in a rate as input and rounds it to a rate that the clk can actually
901 * use which is then returned. If clk doesn't support round_rate operation
902 * then the parent rate is returned.
904 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
909 ret
= __clk_round_rate(clk
, rate
);
910 clk_prepare_unlock();
914 EXPORT_SYMBOL_GPL(clk_round_rate
);
917 * __clk_notify - call clk notifier chain
918 * @clk: struct clk * that is changing rate
919 * @msg: clk notifier type (see include/linux/clk.h)
920 * @old_rate: old clk rate
921 * @new_rate: new clk rate
923 * Triggers a notifier call chain on the clk rate-change notification
924 * for 'clk'. Passes a pointer to the struct clk and the previous
925 * and current rates to the notifier callback. Intended to be called by
926 * internal clock code only. Returns NOTIFY_DONE from the last driver
927 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
928 * a driver returns that.
930 static int __clk_notify(struct clk
*clk
, unsigned long msg
,
931 unsigned long old_rate
, unsigned long new_rate
)
933 struct clk_notifier
*cn
;
934 struct clk_notifier_data cnd
;
935 int ret
= NOTIFY_DONE
;
938 cnd
.old_rate
= old_rate
;
939 cnd
.new_rate
= new_rate
;
941 list_for_each_entry(cn
, &clk_notifier_list
, node
) {
942 if (cn
->clk
== clk
) {
943 ret
= srcu_notifier_call_chain(&cn
->notifier_head
, msg
,
954 * @clk: first clk in the subtree
955 * @msg: notification type (see include/linux/clk.h)
957 * Walks the subtree of clks starting with clk and recalculates rates as it
958 * goes. Note that if a clk does not implement the .recalc_rate callback then
959 * it is assumed that the clock will take on the rate of it's parent.
961 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
964 * Caller must hold prepare_lock.
966 static void __clk_recalc_rates(struct clk
*clk
, unsigned long msg
)
968 unsigned long old_rate
;
969 unsigned long parent_rate
= 0;
972 old_rate
= clk
->rate
;
975 parent_rate
= clk
->parent
->rate
;
977 if (clk
->ops
->recalc_rate
)
978 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
980 clk
->rate
= parent_rate
;
983 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
984 * & ABORT_RATE_CHANGE notifiers
986 if (clk
->notifier_count
&& msg
)
987 __clk_notify(clk
, msg
, old_rate
, clk
->rate
);
989 hlist_for_each_entry(child
, &clk
->children
, child_node
)
990 __clk_recalc_rates(child
, msg
);
994 * clk_get_rate - return the rate of clk
995 * @clk: the clk whose rate is being returned
997 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
998 * is set, which means a recalc_rate will be issued.
999 * If clk is NULL then returns 0.
1001 unsigned long clk_get_rate(struct clk
*clk
)
1007 if (clk
&& (clk
->flags
& CLK_GET_RATE_NOCACHE
))
1008 __clk_recalc_rates(clk
, 0);
1010 rate
= __clk_get_rate(clk
);
1011 clk_prepare_unlock();
1015 EXPORT_SYMBOL_GPL(clk_get_rate
);
1018 * __clk_speculate_rates
1019 * @clk: first clk in the subtree
1020 * @parent_rate: the "future" rate of clk's parent
1022 * Walks the subtree of clks starting with clk, speculating rates as it
1023 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1025 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1026 * pre-rate change notifications and returns early if no clks in the
1027 * subtree have subscribed to the notifications. Note that if a clk does not
1028 * implement the .recalc_rate callback then it is assumed that the clock will
1029 * take on the rate of it's parent.
1031 * Caller must hold prepare_lock.
1033 static int __clk_speculate_rates(struct clk
*clk
, unsigned long parent_rate
)
1036 unsigned long new_rate
;
1037 int ret
= NOTIFY_DONE
;
1039 if (clk
->ops
->recalc_rate
)
1040 new_rate
= clk
->ops
->recalc_rate(clk
->hw
, parent_rate
);
1042 new_rate
= parent_rate
;
1044 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1045 if (clk
->notifier_count
)
1046 ret
= __clk_notify(clk
, PRE_RATE_CHANGE
, clk
->rate
, new_rate
);
1048 if (ret
& NOTIFY_STOP_MASK
)
1051 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1052 ret
= __clk_speculate_rates(child
, new_rate
);
1053 if (ret
& NOTIFY_STOP_MASK
)
1061 static void clk_calc_subtree(struct clk
*clk
, unsigned long new_rate
)
1065 clk
->new_rate
= new_rate
;
1067 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1068 if (child
->ops
->recalc_rate
)
1069 child
->new_rate
= child
->ops
->recalc_rate(child
->hw
, new_rate
);
1071 child
->new_rate
= new_rate
;
1072 clk_calc_subtree(child
, child
->new_rate
);
1077 * calculate the new rates returning the topmost clock that has to be
1080 static struct clk
*clk_calc_new_rates(struct clk
*clk
, unsigned long rate
)
1082 struct clk
*top
= clk
;
1083 unsigned long best_parent_rate
= 0;
1084 unsigned long new_rate
;
1087 if (IS_ERR_OR_NULL(clk
))
1090 /* save parent rate, if it exists */
1092 best_parent_rate
= clk
->parent
->rate
;
1094 /* never propagate up to the parent */
1095 if (!(clk
->flags
& CLK_SET_RATE_PARENT
)) {
1096 if (!clk
->ops
->round_rate
) {
1097 clk
->new_rate
= clk
->rate
;
1100 new_rate
= clk
->ops
->round_rate(clk
->hw
, rate
, &best_parent_rate
);
1104 /* need clk->parent from here on out */
1106 pr_debug("%s: %s has NULL parent\n", __func__
, clk
->name
);
1110 if (!clk
->ops
->round_rate
) {
1111 top
= clk_calc_new_rates(clk
->parent
, rate
);
1112 new_rate
= clk
->parent
->new_rate
;
1117 new_rate
= clk
->ops
->round_rate(clk
->hw
, rate
, &best_parent_rate
);
1119 if (best_parent_rate
!= clk
->parent
->rate
) {
1120 top
= clk_calc_new_rates(clk
->parent
, best_parent_rate
);
1126 clk_calc_subtree(clk
, new_rate
);
1132 * Notify about rate changes in a subtree. Always walk down the whole tree
1133 * so that in case of an error we can walk down the whole tree again and
1136 static struct clk
*clk_propagate_rate_change(struct clk
*clk
, unsigned long event
)
1138 struct clk
*child
, *fail_clk
= NULL
;
1139 int ret
= NOTIFY_DONE
;
1141 if (clk
->rate
== clk
->new_rate
)
1144 if (clk
->notifier_count
) {
1145 ret
= __clk_notify(clk
, event
, clk
->rate
, clk
->new_rate
);
1146 if (ret
& NOTIFY_STOP_MASK
)
1150 hlist_for_each_entry(child
, &clk
->children
, child_node
) {
1151 clk
= clk_propagate_rate_change(child
, event
);
1160 * walk down a subtree and set the new rates notifying the rate
1163 static void clk_change_rate(struct clk
*clk
)
1166 unsigned long old_rate
;
1167 unsigned long best_parent_rate
= 0;
1169 old_rate
= clk
->rate
;
1172 best_parent_rate
= clk
->parent
->rate
;
1174 if (clk
->ops
->set_rate
)
1175 clk
->ops
->set_rate(clk
->hw
, clk
->new_rate
, best_parent_rate
);
1177 if (clk
->ops
->recalc_rate
)
1178 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
, best_parent_rate
);
1180 clk
->rate
= best_parent_rate
;
1182 if (clk
->notifier_count
&& old_rate
!= clk
->rate
)
1183 __clk_notify(clk
, POST_RATE_CHANGE
, old_rate
, clk
->rate
);
1185 hlist_for_each_entry(child
, &clk
->children
, child_node
)
1186 clk_change_rate(child
);
1190 * clk_set_rate - specify a new rate for clk
1191 * @clk: the clk whose rate is being changed
1192 * @rate: the new rate for clk
1194 * In the simplest case clk_set_rate will only adjust the rate of clk.
1196 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1197 * propagate up to clk's parent; whether or not this happens depends on the
1198 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1199 * after calling .round_rate then upstream parent propagation is ignored. If
1200 * *parent_rate comes back with a new rate for clk's parent then we propagate
1201 * up to clk's parent and set it's rate. Upward propagation will continue
1202 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1203 * .round_rate stops requesting changes to clk's parent_rate.
1205 * Rate changes are accomplished via tree traversal that also recalculates the
1206 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1208 * Returns 0 on success, -EERROR otherwise.
1210 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
1212 struct clk
*top
, *fail_clk
;
1215 /* prevent racing with updates to the clock topology */
1218 /* bail early if nothing to do */
1219 if (rate
== clk
->rate
)
1222 if ((clk
->flags
& CLK_SET_RATE_GATE
) && clk
->prepare_count
) {
1227 /* calculate new rates and get the topmost changed clock */
1228 top
= clk_calc_new_rates(clk
, rate
);
1234 /* notify that we are about to change rates */
1235 fail_clk
= clk_propagate_rate_change(top
, PRE_RATE_CHANGE
);
1237 pr_warn("%s: failed to set %s rate\n", __func__
,
1239 clk_propagate_rate_change(top
, ABORT_RATE_CHANGE
);
1244 /* change the rates */
1245 clk_change_rate(top
);
1248 clk_prepare_unlock();
1252 EXPORT_SYMBOL_GPL(clk_set_rate
);
1255 * clk_get_parent - return the parent of a clk
1256 * @clk: the clk whose parent gets returned
1258 * Simply returns clk->parent. Returns NULL if clk is NULL.
1260 struct clk
*clk_get_parent(struct clk
*clk
)
1265 parent
= __clk_get_parent(clk
);
1266 clk_prepare_unlock();
1270 EXPORT_SYMBOL_GPL(clk_get_parent
);
1273 * .get_parent is mandatory for clocks with multiple possible parents. It is
1274 * optional for single-parent clocks. Always call .get_parent if it is
1275 * available and WARN if it is missing for multi-parent clocks.
1277 * For single-parent clocks without .get_parent, first check to see if the
1278 * .parents array exists, and if so use it to avoid an expensive tree
1279 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1281 static struct clk
*__clk_init_parent(struct clk
*clk
)
1283 struct clk
*ret
= NULL
;
1286 /* handle the trivial cases */
1288 if (!clk
->num_parents
)
1291 if (clk
->num_parents
== 1) {
1292 if (IS_ERR_OR_NULL(clk
->parent
))
1293 ret
= clk
->parent
= __clk_lookup(clk
->parent_names
[0]);
1298 if (!clk
->ops
->get_parent
) {
1299 WARN(!clk
->ops
->get_parent
,
1300 "%s: multi-parent clocks must implement .get_parent\n",
1306 * Do our best to cache parent clocks in clk->parents. This prevents
1307 * unnecessary and expensive calls to __clk_lookup. We don't set
1308 * clk->parent here; that is done by the calling function
1311 index
= clk
->ops
->get_parent(clk
->hw
);
1315 kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1319 ret
= __clk_lookup(clk
->parent_names
[index
]);
1320 else if (!clk
->parents
[index
])
1321 ret
= clk
->parents
[index
] =
1322 __clk_lookup(clk
->parent_names
[index
]);
1324 ret
= clk
->parents
[index
];
1330 static void clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1332 hlist_del(&clk
->child_node
);
1335 hlist_add_head(&clk
->child_node
, &new_parent
->children
);
1337 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1339 clk
->parent
= new_parent
;
1342 void __clk_reparent(struct clk
*clk
, struct clk
*new_parent
)
1344 clk_reparent(clk
, new_parent
);
1345 clk_debug_reparent(clk
, new_parent
);
1346 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1349 static u8
clk_fetch_parent_index(struct clk
*clk
, struct clk
*parent
)
1354 clk
->parents
= kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1358 * find index of new parent clock using cached parent ptrs,
1359 * or if not yet cached, use string name comparison and cache
1360 * them now to avoid future calls to __clk_lookup.
1362 for (i
= 0; i
< clk
->num_parents
; i
++) {
1363 if (clk
->parents
&& clk
->parents
[i
] == parent
)
1365 else if (!strcmp(clk
->parent_names
[i
], parent
->name
)) {
1367 clk
->parents
[i
] = __clk_lookup(parent
->name
);
1375 static int __clk_set_parent(struct clk
*clk
, struct clk
*parent
, u8 p_index
)
1377 unsigned long flags
;
1379 struct clk
*old_parent
= clk
->parent
;
1380 bool migrated_enable
= false;
1382 /* migrate prepare */
1383 if (clk
->prepare_count
)
1384 __clk_prepare(parent
);
1386 flags
= clk_enable_lock();
1388 /* migrate enable */
1389 if (clk
->enable_count
) {
1390 __clk_enable(parent
);
1391 migrated_enable
= true;
1394 /* update the clk tree topology */
1395 clk_reparent(clk
, parent
);
1397 clk_enable_unlock(flags
);
1399 /* change clock input source */
1400 if (parent
&& clk
->ops
->set_parent
)
1401 ret
= clk
->ops
->set_parent(clk
->hw
, p_index
);
1405 * The error handling is tricky due to that we need to release
1406 * the spinlock while issuing the .set_parent callback. This
1407 * means the new parent might have been enabled/disabled in
1408 * between, which must be considered when doing rollback.
1410 flags
= clk_enable_lock();
1412 clk_reparent(clk
, old_parent
);
1414 if (migrated_enable
&& clk
->enable_count
) {
1415 __clk_disable(parent
);
1416 } else if (migrated_enable
&& (clk
->enable_count
== 0)) {
1417 __clk_disable(old_parent
);
1418 } else if (!migrated_enable
&& clk
->enable_count
) {
1419 __clk_disable(parent
);
1420 __clk_enable(old_parent
);
1423 clk_enable_unlock(flags
);
1425 if (clk
->prepare_count
)
1426 __clk_unprepare(parent
);
1431 /* clean up enable for old parent if migration was done */
1432 if (migrated_enable
) {
1433 flags
= clk_enable_lock();
1434 __clk_disable(old_parent
);
1435 clk_enable_unlock(flags
);
1438 /* clean up prepare for old parent if migration was done */
1439 if (clk
->prepare_count
)
1440 __clk_unprepare(old_parent
);
1442 /* update debugfs with new clk tree topology */
1443 clk_debug_reparent(clk
, parent
);
1448 * clk_set_parent - switch the parent of a mux clk
1449 * @clk: the mux clk whose input we are switching
1450 * @parent: the new input to clk
1452 * Re-parent clk to use parent as it's new input source. If clk has the
1453 * CLK_SET_PARENT_GATE flag set then clk must be gated for this
1454 * operation to succeed. After successfully changing clk's parent
1455 * clk_set_parent will update the clk topology, sysfs topology and
1456 * propagate rate recalculation via __clk_recalc_rates. Returns 0 on
1457 * success, -EERROR otherwise.
1459 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
1463 unsigned long p_rate
= 0;
1465 if (!clk
|| !clk
->ops
)
1468 /* verify ops for for multi-parent clks */
1469 if ((clk
->num_parents
> 1) && (!clk
->ops
->set_parent
))
1472 /* prevent racing with updates to the clock topology */
1475 if (clk
->parent
== parent
)
1478 /* check that we are allowed to re-parent if the clock is in use */
1479 if ((clk
->flags
& CLK_SET_PARENT_GATE
) && clk
->prepare_count
) {
1484 /* try finding the new parent index */
1486 p_index
= clk_fetch_parent_index(clk
, parent
);
1487 p_rate
= parent
->rate
;
1488 if (p_index
== clk
->num_parents
) {
1489 pr_debug("%s: clk %s can not be parent of clk %s\n",
1490 __func__
, parent
->name
, clk
->name
);
1496 /* propagate PRE_RATE_CHANGE notifications */
1497 if (clk
->notifier_count
)
1498 ret
= __clk_speculate_rates(clk
, p_rate
);
1500 /* abort if a driver objects */
1501 if (ret
& NOTIFY_STOP_MASK
)
1504 /* do the re-parent */
1505 ret
= __clk_set_parent(clk
, parent
, p_index
);
1507 /* propagate rate recalculation accordingly */
1509 __clk_recalc_rates(clk
, ABORT_RATE_CHANGE
);
1511 __clk_recalc_rates(clk
, POST_RATE_CHANGE
);
1514 clk_prepare_unlock();
1518 EXPORT_SYMBOL_GPL(clk_set_parent
);
1521 * __clk_init - initialize the data structures in a struct clk
1522 * @dev: device initializing this clk, placeholder for now
1523 * @clk: clk being initialized
1525 * Initializes the lists in struct clk, queries the hardware for the
1526 * parent and rate and sets them both.
1528 int __clk_init(struct device
*dev
, struct clk
*clk
)
1532 struct hlist_node
*tmp2
;
1539 /* check to see if a clock with this name is already registered */
1540 if (__clk_lookup(clk
->name
)) {
1541 pr_debug("%s: clk %s already initialized\n",
1542 __func__
, clk
->name
);
1547 /* check that clk_ops are sane. See Documentation/clk.txt */
1548 if (clk
->ops
->set_rate
&&
1549 !(clk
->ops
->round_rate
&& clk
->ops
->recalc_rate
)) {
1550 pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
1551 __func__
, clk
->name
);
1556 if (clk
->ops
->set_parent
&& !clk
->ops
->get_parent
) {
1557 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1558 __func__
, clk
->name
);
1563 /* throw a WARN if any entries in parent_names are NULL */
1564 for (i
= 0; i
< clk
->num_parents
; i
++)
1565 WARN(!clk
->parent_names
[i
],
1566 "%s: invalid NULL in %s's .parent_names\n",
1567 __func__
, clk
->name
);
1570 * Allocate an array of struct clk *'s to avoid unnecessary string
1571 * look-ups of clk's possible parents. This can fail for clocks passed
1572 * in to clk_init during early boot; thus any access to clk->parents[]
1573 * must always check for a NULL pointer and try to populate it if
1576 * If clk->parents is not NULL we skip this entire block. This allows
1577 * for clock drivers to statically initialize clk->parents.
1579 if (clk
->num_parents
> 1 && !clk
->parents
) {
1580 clk
->parents
= kzalloc((sizeof(struct clk
*) * clk
->num_parents
),
1583 * __clk_lookup returns NULL for parents that have not been
1584 * clk_init'd; thus any access to clk->parents[] must check
1585 * for a NULL pointer. We can always perform lazy lookups for
1586 * missing parents later on.
1589 for (i
= 0; i
< clk
->num_parents
; i
++)
1591 __clk_lookup(clk
->parent_names
[i
]);
1594 clk
->parent
= __clk_init_parent(clk
);
1597 * Populate clk->parent if parent has already been __clk_init'd. If
1598 * parent has not yet been __clk_init'd then place clk in the orphan
1599 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1602 * Every time a new clk is clk_init'd then we walk the list of orphan
1603 * clocks and re-parent any that are children of the clock currently
1607 hlist_add_head(&clk
->child_node
,
1608 &clk
->parent
->children
);
1609 else if (clk
->flags
& CLK_IS_ROOT
)
1610 hlist_add_head(&clk
->child_node
, &clk_root_list
);
1612 hlist_add_head(&clk
->child_node
, &clk_orphan_list
);
1615 * Set clk's rate. The preferred method is to use .recalc_rate. For
1616 * simple clocks and lazy developers the default fallback is to use the
1617 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1618 * then rate is set to zero.
1620 if (clk
->ops
->recalc_rate
)
1621 clk
->rate
= clk
->ops
->recalc_rate(clk
->hw
,
1622 __clk_get_rate(clk
->parent
));
1623 else if (clk
->parent
)
1624 clk
->rate
= clk
->parent
->rate
;
1629 * walk the list of orphan clocks and reparent any that are children of
1632 hlist_for_each_entry_safe(orphan
, tmp2
, &clk_orphan_list
, child_node
) {
1633 if (orphan
->ops
->get_parent
) {
1634 i
= orphan
->ops
->get_parent(orphan
->hw
);
1635 if (!strcmp(clk
->name
, orphan
->parent_names
[i
]))
1636 __clk_reparent(orphan
, clk
);
1640 for (i
= 0; i
< orphan
->num_parents
; i
++)
1641 if (!strcmp(clk
->name
, orphan
->parent_names
[i
])) {
1642 __clk_reparent(orphan
, clk
);
1648 * optional platform-specific magic
1650 * The .init callback is not used by any of the basic clock types, but
1651 * exists for weird hardware that must perform initialization magic.
1652 * Please consider other ways of solving initialization problems before
1653 * using this callback, as it's use is discouraged.
1656 clk
->ops
->init(clk
->hw
);
1658 clk_debug_register(clk
);
1661 clk_prepare_unlock();
1667 * __clk_register - register a clock and return a cookie.
1669 * Same as clk_register, except that the .clk field inside hw shall point to a
1670 * preallocated (generally statically allocated) struct clk. None of the fields
1671 * of the struct clk need to be initialized.
1673 * The data pointed to by .init and .clk field shall NOT be marked as init
1676 * __clk_register is only exposed via clk-private.h and is intended for use with
1677 * very large numbers of clocks that need to be statically initialized. It is
1678 * a layering violation to include clk-private.h from any code which implements
1679 * a clock's .ops; as such any statically initialized clock data MUST be in a
1680 * separate C file from the logic that implements it's operations. Returns 0
1681 * on success, otherwise an error code.
1683 struct clk
*__clk_register(struct device
*dev
, struct clk_hw
*hw
)
1689 clk
->name
= hw
->init
->name
;
1690 clk
->ops
= hw
->init
->ops
;
1692 clk
->flags
= hw
->init
->flags
;
1693 clk
->parent_names
= hw
->init
->parent_names
;
1694 clk
->num_parents
= hw
->init
->num_parents
;
1696 ret
= __clk_init(dev
, clk
);
1698 return ERR_PTR(ret
);
1702 EXPORT_SYMBOL_GPL(__clk_register
);
1704 static int _clk_register(struct device
*dev
, struct clk_hw
*hw
, struct clk
*clk
)
1708 clk
->name
= kstrdup(hw
->init
->name
, GFP_KERNEL
);
1710 pr_err("%s: could not allocate clk->name\n", __func__
);
1714 clk
->ops
= hw
->init
->ops
;
1716 clk
->flags
= hw
->init
->flags
;
1717 clk
->num_parents
= hw
->init
->num_parents
;
1720 /* allocate local copy in case parent_names is __initdata */
1721 clk
->parent_names
= kzalloc((sizeof(char*) * clk
->num_parents
),
1724 if (!clk
->parent_names
) {
1725 pr_err("%s: could not allocate clk->parent_names\n", __func__
);
1727 goto fail_parent_names
;
1731 /* copy each string name in case parent_names is __initdata */
1732 for (i
= 0; i
< clk
->num_parents
; i
++) {
1733 clk
->parent_names
[i
] = kstrdup(hw
->init
->parent_names
[i
],
1735 if (!clk
->parent_names
[i
]) {
1736 pr_err("%s: could not copy parent_names\n", __func__
);
1738 goto fail_parent_names_copy
;
1742 ret
= __clk_init(dev
, clk
);
1746 fail_parent_names_copy
:
1748 kfree(clk
->parent_names
[i
]);
1749 kfree(clk
->parent_names
);
1757 * clk_register - allocate a new clock, register it and return an opaque cookie
1758 * @dev: device that is registering this clock
1759 * @hw: link to hardware-specific clock data
1761 * clk_register is the primary interface for populating the clock tree with new
1762 * clock nodes. It returns a pointer to the newly allocated struct clk which
1763 * cannot be dereferenced by driver code but may be used in conjuction with the
1764 * rest of the clock API. In the event of an error clk_register will return an
1765 * error code; drivers must test for an error code after calling clk_register.
1767 struct clk
*clk_register(struct device
*dev
, struct clk_hw
*hw
)
1772 clk
= kzalloc(sizeof(*clk
), GFP_KERNEL
);
1774 pr_err("%s: could not allocate clk\n", __func__
);
1779 ret
= _clk_register(dev
, hw
, clk
);
1785 return ERR_PTR(ret
);
1787 EXPORT_SYMBOL_GPL(clk_register
);
1790 * clk_unregister - unregister a currently registered clock
1791 * @clk: clock to unregister
1793 * Currently unimplemented.
1795 void clk_unregister(struct clk
*clk
) {}
1796 EXPORT_SYMBOL_GPL(clk_unregister
);
1798 static void devm_clk_release(struct device
*dev
, void *res
)
1800 clk_unregister(res
);
1804 * devm_clk_register - resource managed clk_register()
1805 * @dev: device that is registering this clock
1806 * @hw: link to hardware-specific clock data
1808 * Managed clk_register(). Clocks returned from this function are
1809 * automatically clk_unregister()ed on driver detach. See clk_register() for
1812 struct clk
*devm_clk_register(struct device
*dev
, struct clk_hw
*hw
)
1817 clk
= devres_alloc(devm_clk_release
, sizeof(*clk
), GFP_KERNEL
);
1819 return ERR_PTR(-ENOMEM
);
1821 ret
= _clk_register(dev
, hw
, clk
);
1823 devres_add(dev
, clk
);
1831 EXPORT_SYMBOL_GPL(devm_clk_register
);
1833 static int devm_clk_match(struct device
*dev
, void *res
, void *data
)
1835 struct clk
*c
= res
;
1842 * devm_clk_unregister - resource managed clk_unregister()
1843 * @clk: clock to unregister
1845 * Deallocate a clock allocated with devm_clk_register(). Normally
1846 * this function will not need to be called and the resource management
1847 * code will ensure that the resource is freed.
1849 void devm_clk_unregister(struct device
*dev
, struct clk
*clk
)
1851 WARN_ON(devres_release(dev
, devm_clk_release
, devm_clk_match
, clk
));
1853 EXPORT_SYMBOL_GPL(devm_clk_unregister
);
1855 /*** clk rate change notifiers ***/
1858 * clk_notifier_register - add a clk rate change notifier
1859 * @clk: struct clk * to watch
1860 * @nb: struct notifier_block * with callback info
1862 * Request notification when clk's rate changes. This uses an SRCU
1863 * notifier because we want it to block and notifier unregistrations are
1864 * uncommon. The callbacks associated with the notifier must not
1865 * re-enter into the clk framework by calling any top-level clk APIs;
1866 * this will cause a nested prepare_lock mutex.
1868 * Pre-change notifier callbacks will be passed the current, pre-change
1869 * rate of the clk via struct clk_notifier_data.old_rate. The new,
1870 * post-change rate of the clk is passed via struct
1871 * clk_notifier_data.new_rate.
1873 * Post-change notifiers will pass the now-current, post-change rate of
1874 * the clk in both struct clk_notifier_data.old_rate and struct
1875 * clk_notifier_data.new_rate.
1877 * Abort-change notifiers are effectively the opposite of pre-change
1878 * notifiers: the original pre-change clk rate is passed in via struct
1879 * clk_notifier_data.new_rate and the failed post-change rate is passed
1880 * in via struct clk_notifier_data.old_rate.
1882 * clk_notifier_register() must be called from non-atomic context.
1883 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1884 * allocation failure; otherwise, passes along the return value of
1885 * srcu_notifier_chain_register().
1887 int clk_notifier_register(struct clk
*clk
, struct notifier_block
*nb
)
1889 struct clk_notifier
*cn
;
1897 /* search the list of notifiers for this clk */
1898 list_for_each_entry(cn
, &clk_notifier_list
, node
)
1902 /* if clk wasn't in the notifier list, allocate new clk_notifier */
1903 if (cn
->clk
!= clk
) {
1904 cn
= kzalloc(sizeof(struct clk_notifier
), GFP_KERNEL
);
1909 srcu_init_notifier_head(&cn
->notifier_head
);
1911 list_add(&cn
->node
, &clk_notifier_list
);
1914 ret
= srcu_notifier_chain_register(&cn
->notifier_head
, nb
);
1916 clk
->notifier_count
++;
1919 clk_prepare_unlock();
1923 EXPORT_SYMBOL_GPL(clk_notifier_register
);
1926 * clk_notifier_unregister - remove a clk rate change notifier
1927 * @clk: struct clk *
1928 * @nb: struct notifier_block * with callback info
1930 * Request no further notification for changes to 'clk' and frees memory
1931 * allocated in clk_notifier_register.
1933 * Returns -EINVAL if called with null arguments; otherwise, passes
1934 * along the return value of srcu_notifier_chain_unregister().
1936 int clk_notifier_unregister(struct clk
*clk
, struct notifier_block
*nb
)
1938 struct clk_notifier
*cn
= NULL
;
1946 list_for_each_entry(cn
, &clk_notifier_list
, node
)
1950 if (cn
->clk
== clk
) {
1951 ret
= srcu_notifier_chain_unregister(&cn
->notifier_head
, nb
);
1953 clk
->notifier_count
--;
1955 /* XXX the notifier code should handle this better */
1956 if (!cn
->notifier_head
.head
) {
1957 srcu_cleanup_notifier_head(&cn
->notifier_head
);
1965 clk_prepare_unlock();
1969 EXPORT_SYMBOL_GPL(clk_notifier_unregister
);
1973 * struct of_clk_provider - Clock provider registration structure
1974 * @link: Entry in global list of clock providers
1975 * @node: Pointer to device tree node of clock provider
1976 * @get: Get clock callback. Returns NULL or a struct clk for the
1977 * given clock specifier
1978 * @data: context pointer to be passed into @get callback
1980 struct of_clk_provider
{
1981 struct list_head link
;
1983 struct device_node
*node
;
1984 struct clk
*(*get
)(struct of_phandle_args
*clkspec
, void *data
);
1988 extern struct of_device_id __clk_of_table
[];
1990 static const struct of_device_id __clk_of_table_sentinel
1991 __used
__section(__clk_of_table_end
);
1993 static LIST_HEAD(of_clk_providers
);
1994 static DEFINE_MUTEX(of_clk_lock
);
1996 struct clk
*of_clk_src_simple_get(struct of_phandle_args
*clkspec
,
2001 EXPORT_SYMBOL_GPL(of_clk_src_simple_get
);
2003 struct clk
*of_clk_src_onecell_get(struct of_phandle_args
*clkspec
, void *data
)
2005 struct clk_onecell_data
*clk_data
= data
;
2006 unsigned int idx
= clkspec
->args
[0];
2008 if (idx
>= clk_data
->clk_num
) {
2009 pr_err("%s: invalid clock index %d\n", __func__
, idx
);
2010 return ERR_PTR(-EINVAL
);
2013 return clk_data
->clks
[idx
];
2015 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get
);
2018 * of_clk_add_provider() - Register a clock provider for a node
2019 * @np: Device node pointer associated with clock provider
2020 * @clk_src_get: callback for decoding clock
2021 * @data: context pointer for @clk_src_get callback.
2023 int of_clk_add_provider(struct device_node
*np
,
2024 struct clk
*(*clk_src_get
)(struct of_phandle_args
*clkspec
,
2028 struct of_clk_provider
*cp
;
2030 cp
= kzalloc(sizeof(struct of_clk_provider
), GFP_KERNEL
);
2034 cp
->node
= of_node_get(np
);
2036 cp
->get
= clk_src_get
;
2038 mutex_lock(&of_clk_lock
);
2039 list_add(&cp
->link
, &of_clk_providers
);
2040 mutex_unlock(&of_clk_lock
);
2041 pr_debug("Added clock from %s\n", np
->full_name
);
2045 EXPORT_SYMBOL_GPL(of_clk_add_provider
);
2048 * of_clk_del_provider() - Remove a previously registered clock provider
2049 * @np: Device node pointer associated with clock provider
2051 void of_clk_del_provider(struct device_node
*np
)
2053 struct of_clk_provider
*cp
;
2055 mutex_lock(&of_clk_lock
);
2056 list_for_each_entry(cp
, &of_clk_providers
, link
) {
2057 if (cp
->node
== np
) {
2058 list_del(&cp
->link
);
2059 of_node_put(cp
->node
);
2064 mutex_unlock(&of_clk_lock
);
2066 EXPORT_SYMBOL_GPL(of_clk_del_provider
);
2068 struct clk
*of_clk_get_from_provider(struct of_phandle_args
*clkspec
)
2070 struct of_clk_provider
*provider
;
2071 struct clk
*clk
= ERR_PTR(-ENOENT
);
2073 /* Check if we have such a provider in our array */
2074 mutex_lock(&of_clk_lock
);
2075 list_for_each_entry(provider
, &of_clk_providers
, link
) {
2076 if (provider
->node
== clkspec
->np
)
2077 clk
= provider
->get(clkspec
, provider
->data
);
2081 mutex_unlock(&of_clk_lock
);
2086 const char *of_clk_get_parent_name(struct device_node
*np
, int index
)
2088 struct of_phandle_args clkspec
;
2089 const char *clk_name
;
2095 rc
= of_parse_phandle_with_args(np
, "clocks", "#clock-cells", index
,
2100 if (of_property_read_string_index(clkspec
.np
, "clock-output-names",
2101 clkspec
.args_count
? clkspec
.args
[0] : 0,
2103 clk_name
= clkspec
.np
->name
;
2105 of_node_put(clkspec
.np
);
2108 EXPORT_SYMBOL_GPL(of_clk_get_parent_name
);
2111 * of_clk_init() - Scan and init clock providers from the DT
2112 * @matches: array of compatible values and init functions for providers.
2114 * This function scans the device tree for matching clock providers and
2115 * calls their initialization functions
2117 void __init
of_clk_init(const struct of_device_id
*matches
)
2119 struct device_node
*np
;
2122 matches
= __clk_of_table
;
2124 for_each_matching_node(np
, matches
) {
2125 const struct of_device_id
*match
= of_match_node(matches
, np
);
2126 of_clk_init_cb_t clk_init_cb
= match
->data
;