2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
12 #include <linux/clk-private.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock.h>
16 #include <linux/err.h>
17 #include <linux/list.h>
18 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
24 static DEFINE_SPINLOCK(enable_lock);
25 static DEFINE_MUTEX(prepare_lock);
27 static struct task_struct *prepare_owner;
28 static struct task_struct *enable_owner;
30 static int prepare_refcnt;
31 static int enable_refcnt;
33 static HLIST_HEAD(clk_root_list);
34 static HLIST_HEAD(clk_orphan_list);
35 static LIST_HEAD(clk_notifier_list);
38 static void clk_prepare_lock(void)
40 if (!mutex_trylock(&prepare_lock)) {
41 if (prepare_owner == current) {
45 mutex_lock(&prepare_lock);
47 WARN_ON_ONCE(prepare_owner != NULL);
48 WARN_ON_ONCE(prepare_refcnt != 0);
49 prepare_owner = current;
53 static void clk_prepare_unlock(void)
55 WARN_ON_ONCE(prepare_owner != current);
56 WARN_ON_ONCE(prepare_refcnt == 0);
61 mutex_unlock(&prepare_lock);
64 static unsigned long clk_enable_lock(void)
68 if (!spin_trylock_irqsave(&enable_lock, flags)) {
69 if (enable_owner == current) {
73 spin_lock_irqsave(&enable_lock, flags);
75 WARN_ON_ONCE(enable_owner != NULL);
76 WARN_ON_ONCE(enable_refcnt != 0);
77 enable_owner = current;
82 static void clk_enable_unlock(unsigned long flags)
84 WARN_ON_ONCE(enable_owner != current);
85 WARN_ON_ONCE(enable_refcnt == 0);
90 spin_unlock_irqrestore(&enable_lock, flags);
93 /*** debugfs support ***/
95 #ifdef CONFIG_COMMON_CLK_DEBUG
96 #include <linux/debugfs.h>
98 static struct dentry *rootdir;
99 static struct dentry *orphandir;
100 static int inited = 0;
102 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
107 seq_printf(s, "%*s%-*s %-11d %-12d %-10lu",
109 30 - level * 3, c->name,
110 c->enable_count, c->prepare_count, clk_get_rate(c));
114 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
122 clk_summary_show_one(s, c, level);
124 hlist_for_each_entry(child, &c->children, child_node)
125 clk_summary_show_subtree(s, child, level + 1);
128 static int clk_summary_show(struct seq_file *s, void *data)
132 seq_printf(s, " clock enable_cnt prepare_cnt rate\n");
133 seq_printf(s, "---------------------------------------------------------------------\n");
137 hlist_for_each_entry(c, &clk_root_list, child_node)
138 clk_summary_show_subtree(s, c, 0);
140 hlist_for_each_entry(c, &clk_orphan_list, child_node)
141 clk_summary_show_subtree(s, c, 0);
143 clk_prepare_unlock();
149 static int clk_summary_open(struct inode *inode, struct file *file)
151 return single_open(file, clk_summary_show, inode->i_private);
154 static const struct file_operations clk_summary_fops = {
155 .open = clk_summary_open,
158 .release = single_release,
161 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
166 seq_printf(s, "\"%s\": { ", c->name);
167 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
168 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
169 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
172 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
179 clk_dump_one(s, c, level);
181 hlist_for_each_entry(child, &c->children, child_node) {
183 clk_dump_subtree(s, child, level + 1);
189 static int clk_dump(struct seq_file *s, void *data)
192 bool first_node = true;
198 hlist_for_each_entry(c, &clk_root_list, child_node) {
202 clk_dump_subtree(s, c, 0);
205 hlist_for_each_entry(c, &clk_orphan_list, child_node) {
207 clk_dump_subtree(s, c, 0);
210 clk_prepare_unlock();
217 static int clk_dump_open(struct inode *inode, struct file *file)
219 return single_open(file, clk_dump, inode->i_private);
222 static const struct file_operations clk_dump_fops = {
223 .open = clk_dump_open,
226 .release = single_release,
229 /* caller must hold prepare_lock */
230 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
235 if (!clk || !pdentry) {
240 d = debugfs_create_dir(clk->name, pdentry);
246 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
251 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
256 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
257 (u32 *)&clk->prepare_count);
261 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
262 (u32 *)&clk->enable_count);
266 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
267 (u32 *)&clk->notifier_count);
275 debugfs_remove(clk->dentry);
280 /* caller must hold prepare_lock */
281 static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
286 if (!clk || !pdentry)
289 ret = clk_debug_create_one(clk, pdentry);
294 hlist_for_each_entry(child, &clk->children, child_node)
295 clk_debug_create_subtree(child, clk->dentry);
303 * clk_debug_register - add a clk node to the debugfs clk tree
304 * @clk: the clk being added to the debugfs clk tree
306 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
307 * initialized. Otherwise it bails out early since the debugfs clk tree
308 * will be created lazily by clk_debug_init as part of a late_initcall.
310 * Caller must hold prepare_lock. Only clk_init calls this function (so
311 * far) so this is taken care.
313 static int clk_debug_register(struct clk *clk)
316 struct dentry *pdentry;
322 parent = clk->parent;
325 * Check to see if a clk is a root clk. Also check that it is
326 * safe to add this clk to debugfs
329 if (clk->flags & CLK_IS_ROOT)
335 pdentry = parent->dentry;
339 ret = clk_debug_create_subtree(clk, pdentry);
346 * clk_debug_reparent - reparent clk node in the debugfs clk tree
347 * @clk: the clk being reparented
348 * @new_parent: the new clk parent, may be NULL
350 * Rename clk entry in the debugfs clk tree if debugfs has been
351 * initialized. Otherwise it bails out early since the debugfs clk tree
352 * will be created lazily by clk_debug_init as part of a late_initcall.
354 * Caller must hold prepare_lock.
356 static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
359 struct dentry *new_parent_d;
365 new_parent_d = new_parent->dentry;
367 new_parent_d = orphandir;
369 d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
370 new_parent_d, clk->name);
374 pr_debug("%s: failed to rename debugfs entry for %s\n",
375 __func__, clk->name);
379 * clk_debug_init - lazily create the debugfs clk tree visualization
381 * clks are often initialized very early during boot before memory can
382 * be dynamically allocated and well before debugfs is setup.
383 * clk_debug_init walks the clk tree hierarchy while holding
384 * prepare_lock and creates the topology as part of a late_initcall,
385 * thus insuring that clks initialized very early will still be
386 * represented in the debugfs clk tree. This function should only be
387 * called once at boot-time, and all other clks added dynamically will
388 * be done so with clk_debug_register.
390 static int __init clk_debug_init(void)
395 rootdir = debugfs_create_dir("clk", NULL);
400 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
405 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
410 orphandir = debugfs_create_dir("orphans", rootdir);
417 hlist_for_each_entry(clk, &clk_root_list, child_node)
418 clk_debug_create_subtree(clk, rootdir);
420 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
421 clk_debug_create_subtree(clk, orphandir);
425 clk_prepare_unlock();
429 late_initcall(clk_debug_init);
431 static inline int clk_debug_register(struct clk *clk) { return 0; }
432 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
437 /* caller must hold prepare_lock */
438 static void clk_unprepare_unused_subtree(struct clk *clk)
445 hlist_for_each_entry(child, &clk->children, child_node)
446 clk_unprepare_unused_subtree(child);
448 if (clk->prepare_count)
451 if (clk->flags & CLK_IGNORE_UNUSED)
454 if (__clk_is_prepared(clk)) {
455 if (clk->ops->unprepare_unused)
456 clk->ops->unprepare_unused(clk->hw);
457 else if (clk->ops->unprepare)
458 clk->ops->unprepare(clk->hw);
461 EXPORT_SYMBOL_GPL(__clk_get_flags);
463 /* caller must hold prepare_lock */
464 static void clk_disable_unused_subtree(struct clk *clk)
472 hlist_for_each_entry(child, &clk->children, child_node)
473 clk_disable_unused_subtree(child);
475 flags = clk_enable_lock();
477 if (clk->enable_count)
480 if (clk->flags & CLK_IGNORE_UNUSED)
484 * some gate clocks have special needs during the disable-unused
485 * sequence. call .disable_unused if available, otherwise fall
488 if (__clk_is_enabled(clk)) {
489 if (clk->ops->disable_unused)
490 clk->ops->disable_unused(clk->hw);
491 else if (clk->ops->disable)
492 clk->ops->disable(clk->hw);
496 clk_enable_unlock(flags);
502 static bool clk_ignore_unused;
503 static int __init clk_ignore_unused_setup(char *__unused)
505 clk_ignore_unused = true;
508 __setup("clk_ignore_unused", clk_ignore_unused_setup);
510 static int clk_disable_unused(void)
514 if (clk_ignore_unused) {
515 pr_warn("clk: Not disabling unused clocks\n");
521 hlist_for_each_entry(clk, &clk_root_list, child_node)
522 clk_disable_unused_subtree(clk);
524 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
525 clk_disable_unused_subtree(clk);
527 hlist_for_each_entry(clk, &clk_root_list, child_node)
528 clk_unprepare_unused_subtree(clk);
530 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
531 clk_unprepare_unused_subtree(clk);
533 clk_prepare_unlock();
537 late_initcall_sync(clk_disable_unused);
539 /*** helper functions ***/
541 const char *__clk_get_name(struct clk *clk)
543 return !clk ? NULL : clk->name;
545 EXPORT_SYMBOL_GPL(__clk_get_name);
547 struct clk_hw *__clk_get_hw(struct clk *clk)
549 return !clk ? NULL : clk->hw;
552 u8 __clk_get_num_parents(struct clk *clk)
554 return !clk ? 0 : clk->num_parents;
557 struct clk *__clk_get_parent(struct clk *clk)
559 return !clk ? NULL : clk->parent;
562 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
564 if (!clk || index >= clk->num_parents)
566 else if (!clk->parents)
567 return __clk_lookup(clk->parent_names[index]);
568 else if (!clk->parents[index])
569 return clk->parents[index] =
570 __clk_lookup(clk->parent_names[index]);
572 return clk->parents[index];
575 unsigned int __clk_get_enable_count(struct clk *clk)
577 return !clk ? 0 : clk->enable_count;
580 unsigned int __clk_get_prepare_count(struct clk *clk)
582 return !clk ? 0 : clk->prepare_count;
585 unsigned long __clk_get_rate(struct clk *clk)
596 if (clk->flags & CLK_IS_ROOT)
606 unsigned long __clk_get_flags(struct clk *clk)
608 return !clk ? 0 : clk->flags;
611 bool __clk_is_prepared(struct clk *clk)
619 * .is_prepared is optional for clocks that can prepare
620 * fall back to software usage counter if it is missing
622 if (!clk->ops->is_prepared) {
623 ret = clk->prepare_count ? 1 : 0;
627 ret = clk->ops->is_prepared(clk->hw);
632 bool __clk_is_enabled(struct clk *clk)
640 * .is_enabled is only mandatory for clocks that gate
641 * fall back to software usage counter if .is_enabled is missing
643 if (!clk->ops->is_enabled) {
644 ret = clk->enable_count ? 1 : 0;
648 ret = clk->ops->is_enabled(clk->hw);
653 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
658 if (!strcmp(clk->name, name))
661 hlist_for_each_entry(child, &clk->children, child_node) {
662 ret = __clk_lookup_subtree(name, child);
670 struct clk *__clk_lookup(const char *name)
672 struct clk *root_clk;
678 /* search the 'proper' clk tree first */
679 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
680 ret = __clk_lookup_subtree(name, root_clk);
685 /* if not found, then search the orphan tree */
686 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
687 ret = __clk_lookup_subtree(name, root_clk);
697 void __clk_unprepare(struct clk *clk)
702 if (WARN_ON(clk->prepare_count == 0))
705 if (--clk->prepare_count > 0)
708 WARN_ON(clk->enable_count > 0);
710 if (clk->ops->unprepare)
711 clk->ops->unprepare(clk->hw);
713 __clk_unprepare(clk->parent);
717 * clk_unprepare - undo preparation of a clock source
718 * @clk: the clk being unprepared
720 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
721 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
722 * if the operation may sleep. One example is a clk which is accessed over
723 * I2c. In the complex case a clk gate operation may require a fast and a slow
724 * part. It is this reason that clk_unprepare and clk_disable are not mutually
725 * exclusive. In fact clk_disable must be called before clk_unprepare.
727 void clk_unprepare(struct clk *clk)
730 __clk_unprepare(clk);
731 clk_prepare_unlock();
733 EXPORT_SYMBOL_GPL(clk_unprepare);
735 int __clk_prepare(struct clk *clk)
742 if (clk->prepare_count == 0) {
743 ret = __clk_prepare(clk->parent);
747 if (clk->ops->prepare) {
748 ret = clk->ops->prepare(clk->hw);
750 __clk_unprepare(clk->parent);
756 clk->prepare_count++;
762 * clk_prepare - prepare a clock source
763 * @clk: the clk being prepared
765 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
766 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
767 * operation may sleep. One example is a clk which is accessed over I2c. In
768 * the complex case a clk ungate operation may require a fast and a slow part.
769 * It is this reason that clk_prepare and clk_enable are not mutually
770 * exclusive. In fact clk_prepare must be called before clk_enable.
771 * Returns 0 on success, -EERROR otherwise.
773 int clk_prepare(struct clk *clk)
778 ret = __clk_prepare(clk);
779 clk_prepare_unlock();
783 EXPORT_SYMBOL_GPL(clk_prepare);
785 static void __clk_disable(struct clk *clk)
790 if (WARN_ON(IS_ERR(clk)))
793 if (WARN_ON(clk->enable_count == 0))
796 if (--clk->enable_count > 0)
799 if (clk->ops->disable)
800 clk->ops->disable(clk->hw);
802 __clk_disable(clk->parent);
806 * clk_disable - gate a clock
807 * @clk: the clk being gated
809 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
810 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
811 * clk if the operation is fast and will never sleep. One example is a
812 * SoC-internal clk which is controlled via simple register writes. In the
813 * complex case a clk gate operation may require a fast and a slow part. It is
814 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
815 * In fact clk_disable must be called before clk_unprepare.
817 void clk_disable(struct clk *clk)
821 flags = clk_enable_lock();
823 clk_enable_unlock(flags);
825 EXPORT_SYMBOL_GPL(clk_disable);
827 static int __clk_enable(struct clk *clk)
834 if (WARN_ON(clk->prepare_count == 0))
837 if (clk->enable_count == 0) {
838 ret = __clk_enable(clk->parent);
843 if (clk->ops->enable) {
844 ret = clk->ops->enable(clk->hw);
846 __clk_disable(clk->parent);
857 * clk_enable - ungate a clock
858 * @clk: the clk being ungated
860 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
861 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
862 * if the operation will never sleep. One example is a SoC-internal clk which
863 * is controlled via simple register writes. In the complex case a clk ungate
864 * operation may require a fast and a slow part. It is this reason that
865 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
866 * must be called before clk_enable. Returns 0 on success, -EERROR
869 int clk_enable(struct clk *clk)
874 flags = clk_enable_lock();
875 ret = __clk_enable(clk);
876 clk_enable_unlock(flags);
880 EXPORT_SYMBOL_GPL(clk_enable);
883 * __clk_round_rate - round the given rate for a clk
884 * @clk: round the rate of this clock
885 * @rate: the rate which is to be rounded
887 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
889 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
891 unsigned long parent_rate = 0;
897 parent = clk->parent;
899 parent_rate = parent->rate;
901 if (clk->ops->determine_rate)
902 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
904 else if (clk->ops->round_rate)
905 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
906 else if (clk->flags & CLK_SET_RATE_PARENT)
907 return __clk_round_rate(clk->parent, rate);
913 * clk_round_rate - round the given rate for a clk
914 * @clk: the clk for which we are rounding a rate
915 * @rate: the rate which is to be rounded
917 * Takes in a rate as input and rounds it to a rate that the clk can actually
918 * use which is then returned. If clk doesn't support round_rate operation
919 * then the parent rate is returned.
921 long clk_round_rate(struct clk *clk, unsigned long rate)
926 ret = __clk_round_rate(clk, rate);
927 clk_prepare_unlock();
931 EXPORT_SYMBOL_GPL(clk_round_rate);
934 * __clk_notify - call clk notifier chain
935 * @clk: struct clk * that is changing rate
936 * @msg: clk notifier type (see include/linux/clk.h)
937 * @old_rate: old clk rate
938 * @new_rate: new clk rate
940 * Triggers a notifier call chain on the clk rate-change notification
941 * for 'clk'. Passes a pointer to the struct clk and the previous
942 * and current rates to the notifier callback. Intended to be called by
943 * internal clock code only. Returns NOTIFY_DONE from the last driver
944 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
945 * a driver returns that.
947 static int __clk_notify(struct clk *clk, unsigned long msg,
948 unsigned long old_rate, unsigned long new_rate)
950 struct clk_notifier *cn;
951 struct clk_notifier_data cnd;
952 int ret = NOTIFY_DONE;
955 cnd.old_rate = old_rate;
956 cnd.new_rate = new_rate;
958 list_for_each_entry(cn, &clk_notifier_list, node) {
959 if (cn->clk == clk) {
960 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
971 * @clk: first clk in the subtree
972 * @msg: notification type (see include/linux/clk.h)
974 * Walks the subtree of clks starting with clk and recalculates rates as it
975 * goes. Note that if a clk does not implement the .recalc_rate callback then
976 * it is assumed that the clock will take on the rate of its parent.
978 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
981 * Caller must hold prepare_lock.
983 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
985 unsigned long old_rate;
986 unsigned long parent_rate = 0;
989 old_rate = clk->rate;
992 parent_rate = clk->parent->rate;
994 if (clk->ops->recalc_rate)
995 clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
997 clk->rate = parent_rate;
1000 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1001 * & ABORT_RATE_CHANGE notifiers
1003 if (clk->notifier_count && msg)
1004 __clk_notify(clk, msg, old_rate, clk->rate);
1006 hlist_for_each_entry(child, &clk->children, child_node)
1007 __clk_recalc_rates(child, msg);
1011 * clk_get_rate - return the rate of clk
1012 * @clk: the clk whose rate is being returned
1014 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1015 * is set, which means a recalc_rate will be issued.
1016 * If clk is NULL then returns 0.
1018 unsigned long clk_get_rate(struct clk *clk)
1024 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1025 __clk_recalc_rates(clk, 0);
1027 rate = __clk_get_rate(clk);
1028 clk_prepare_unlock();
1032 EXPORT_SYMBOL_GPL(clk_get_rate);
1034 static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1039 clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1043 * find index of new parent clock using cached parent ptrs,
1044 * or if not yet cached, use string name comparison and cache
1045 * them now to avoid future calls to __clk_lookup.
1047 for (i = 0; i < clk->num_parents; i++) {
1048 if (clk->parents && clk->parents[i] == parent)
1050 else if (!strcmp(clk->parent_names[i], parent->name)) {
1052 clk->parents[i] = __clk_lookup(parent->name);
1060 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1062 /* avoid duplicate POST_RATE_CHANGE notifications */
1063 if (new_parent->new_child == clk)
1064 new_parent->new_child = NULL;
1066 hlist_del(&clk->child_node);
1069 hlist_add_head(&clk->child_node, &new_parent->children);
1071 hlist_add_head(&clk->child_node, &clk_orphan_list);
1073 clk->parent = new_parent;
1076 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1078 unsigned long flags;
1080 struct clk *old_parent = clk->parent;
1083 * Migrate prepare state between parents and prevent race with
1086 * If the clock is not prepared, then a race with
1087 * clk_enable/disable() is impossible since we already have the
1088 * prepare lock (future calls to clk_enable() need to be preceded by
1091 * If the clock is prepared, migrate the prepared state to the new
1092 * parent and also protect against a race with clk_enable() by
1093 * forcing the clock and the new parent on. This ensures that all
1094 * future calls to clk_enable() are practically NOPs with respect to
1095 * hardware and software states.
1097 * See also: Comment for clk_set_parent() below.
1099 if (clk->prepare_count) {
1100 __clk_prepare(parent);
1105 /* update the clk tree topology */
1106 flags = clk_enable_lock();
1107 clk_reparent(clk, parent);
1108 clk_enable_unlock(flags);
1110 /* change clock input source */
1111 if (parent && clk->ops->set_parent)
1112 ret = clk->ops->set_parent(clk->hw, p_index);
1115 flags = clk_enable_lock();
1116 clk_reparent(clk, old_parent);
1117 clk_enable_unlock(flags);
1119 if (clk->prepare_count) {
1121 clk_disable(parent);
1122 __clk_unprepare(parent);
1128 * Finish the migration of prepare state and undo the changes done
1129 * for preventing a race with clk_enable().
1131 if (clk->prepare_count) {
1133 clk_disable(old_parent);
1134 __clk_unprepare(old_parent);
1137 /* update debugfs with new clk tree topology */
1138 clk_debug_reparent(clk, parent);
1143 * __clk_speculate_rates
1144 * @clk: first clk in the subtree
1145 * @parent_rate: the "future" rate of clk's parent
1147 * Walks the subtree of clks starting with clk, speculating rates as it
1148 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1150 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1151 * pre-rate change notifications and returns early if no clks in the
1152 * subtree have subscribed to the notifications. Note that if a clk does not
1153 * implement the .recalc_rate callback then it is assumed that the clock will
1154 * take on the rate of its parent.
1156 * Caller must hold prepare_lock.
1158 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1161 unsigned long new_rate;
1162 int ret = NOTIFY_DONE;
1164 if (clk->ops->recalc_rate)
1165 new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1167 new_rate = parent_rate;
1169 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1170 if (clk->notifier_count)
1171 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1173 if (ret & NOTIFY_STOP_MASK)
1176 hlist_for_each_entry(child, &clk->children, child_node) {
1177 ret = __clk_speculate_rates(child, new_rate);
1178 if (ret & NOTIFY_STOP_MASK)
1186 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1187 struct clk *new_parent, u8 p_index)
1191 clk->new_rate = new_rate;
1192 clk->new_parent = new_parent;
1193 clk->new_parent_index = p_index;
1194 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1195 clk->new_child = NULL;
1196 if (new_parent && new_parent != clk->parent)
1197 new_parent->new_child = clk;
1199 hlist_for_each_entry(child, &clk->children, child_node) {
1200 if (child->ops->recalc_rate)
1201 child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
1203 child->new_rate = new_rate;
1204 clk_calc_subtree(child, child->new_rate, NULL, 0);
1209 * calculate the new rates returning the topmost clock that has to be
1212 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1214 struct clk *top = clk;
1215 struct clk *old_parent, *parent;
1216 unsigned long best_parent_rate = 0;
1217 unsigned long new_rate;
1221 if (IS_ERR_OR_NULL(clk))
1224 /* save parent rate, if it exists */
1225 parent = old_parent = clk->parent;
1227 best_parent_rate = parent->rate;
1229 /* find the closest rate and parent clk/rate */
1230 if (clk->ops->determine_rate) {
1231 new_rate = clk->ops->determine_rate(clk->hw, rate,
1234 } else if (clk->ops->round_rate) {
1235 new_rate = clk->ops->round_rate(clk->hw, rate,
1237 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1238 /* pass-through clock without adjustable parent */
1239 clk->new_rate = clk->rate;
1242 /* pass-through clock with adjustable parent */
1243 top = clk_calc_new_rates(parent, rate);
1244 new_rate = parent->new_rate;
1248 /* some clocks must be gated to change parent */
1249 if (parent != old_parent &&
1250 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1251 pr_debug("%s: %s not gated but wants to reparent\n",
1252 __func__, clk->name);
1256 /* try finding the new parent index */
1258 p_index = clk_fetch_parent_index(clk, parent);
1259 if (p_index == clk->num_parents) {
1260 pr_debug("%s: clk %s can not be parent of clk %s\n",
1261 __func__, parent->name, clk->name);
1266 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1267 best_parent_rate != parent->rate)
1268 top = clk_calc_new_rates(parent, best_parent_rate);
1271 clk_calc_subtree(clk, new_rate, parent, p_index);
1277 * Notify about rate changes in a subtree. Always walk down the whole tree
1278 * so that in case of an error we can walk down the whole tree again and
1281 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1283 struct clk *child, *tmp_clk, *fail_clk = NULL;
1284 int ret = NOTIFY_DONE;
1286 if (clk->rate == clk->new_rate)
1289 if (clk->notifier_count) {
1290 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1291 if (ret & NOTIFY_STOP_MASK)
1295 hlist_for_each_entry(child, &clk->children, child_node) {
1296 /* Skip children who will be reparented to another clock */
1297 if (child->new_parent && child->new_parent != clk)
1299 tmp_clk = clk_propagate_rate_change(child, event);
1304 /* handle the new child who might not be in clk->children yet */
1305 if (clk->new_child) {
1306 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1315 * walk down a subtree and set the new rates notifying the rate
1318 static void clk_change_rate(struct clk *clk)
1321 unsigned long old_rate;
1322 unsigned long best_parent_rate = 0;
1324 old_rate = clk->rate;
1327 if (clk->new_parent && clk->new_parent != clk->parent)
1328 __clk_set_parent(clk, clk->new_parent, clk->new_parent_index);
1331 best_parent_rate = clk->parent->rate;
1333 if (clk->ops->set_rate)
1334 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1336 if (clk->ops->recalc_rate)
1337 clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
1339 clk->rate = best_parent_rate;
1341 if (clk->notifier_count && old_rate != clk->rate)
1342 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1344 hlist_for_each_entry(child, &clk->children, child_node) {
1345 /* Skip children who will be reparented to another clock */
1346 if (child->new_parent && child->new_parent != clk)
1348 clk_change_rate(child);
1351 /* handle the new child who might not be in clk->children yet */
1353 clk_change_rate(clk->new_child);
1357 * clk_set_rate - specify a new rate for clk
1358 * @clk: the clk whose rate is being changed
1359 * @rate: the new rate for clk
1361 * In the simplest case clk_set_rate will only adjust the rate of clk.
1363 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1364 * propagate up to clk's parent; whether or not this happens depends on the
1365 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1366 * after calling .round_rate then upstream parent propagation is ignored. If
1367 * *parent_rate comes back with a new rate for clk's parent then we propagate
1368 * up to clk's parent and set its rate. Upward propagation will continue
1369 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1370 * .round_rate stops requesting changes to clk's parent_rate.
1372 * Rate changes are accomplished via tree traversal that also recalculates the
1373 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1375 * Returns 0 on success, -EERROR otherwise.
1377 int clk_set_rate(struct clk *clk, unsigned long rate)
1379 struct clk *top, *fail_clk;
1382 /* prevent racing with updates to the clock topology */
1385 /* bail early if nothing to do */
1386 if (rate == clk_get_rate(clk))
1389 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1394 /* calculate new rates and get the topmost changed clock */
1395 top = clk_calc_new_rates(clk, rate);
1401 /* notify that we are about to change rates */
1402 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1404 pr_warn("%s: failed to set %s rate\n", __func__,
1406 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1411 /* change the rates */
1412 clk_change_rate(top);
1415 clk_prepare_unlock();
1419 EXPORT_SYMBOL_GPL(clk_set_rate);
1422 * clk_get_parent - return the parent of a clk
1423 * @clk: the clk whose parent gets returned
1425 * Simply returns clk->parent. Returns NULL if clk is NULL.
1427 struct clk *clk_get_parent(struct clk *clk)
1432 parent = __clk_get_parent(clk);
1433 clk_prepare_unlock();
1437 EXPORT_SYMBOL_GPL(clk_get_parent);
1440 * .get_parent is mandatory for clocks with multiple possible parents. It is
1441 * optional for single-parent clocks. Always call .get_parent if it is
1442 * available and WARN if it is missing for multi-parent clocks.
1444 * For single-parent clocks without .get_parent, first check to see if the
1445 * .parents array exists, and if so use it to avoid an expensive tree
1446 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1448 static struct clk *__clk_init_parent(struct clk *clk)
1450 struct clk *ret = NULL;
1453 /* handle the trivial cases */
1455 if (!clk->num_parents)
1458 if (clk->num_parents == 1) {
1459 if (IS_ERR_OR_NULL(clk->parent))
1460 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1465 if (!clk->ops->get_parent) {
1466 WARN(!clk->ops->get_parent,
1467 "%s: multi-parent clocks must implement .get_parent\n",
1473 * Do our best to cache parent clocks in clk->parents. This prevents
1474 * unnecessary and expensive calls to __clk_lookup. We don't set
1475 * clk->parent here; that is done by the calling function
1478 index = clk->ops->get_parent(clk->hw);
1482 kzalloc((sizeof(struct clk*) * clk->num_parents),
1485 ret = clk_get_parent_by_index(clk, index);
1491 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1493 clk_reparent(clk, new_parent);
1494 clk_debug_reparent(clk, new_parent);
1495 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1499 * clk_set_parent - switch the parent of a mux clk
1500 * @clk: the mux clk whose input we are switching
1501 * @parent: the new input to clk
1503 * Re-parent clk to use parent as its new input source. If clk is in
1504 * prepared state, the clk will get enabled for the duration of this call. If
1505 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1506 * that, the reparenting is glitchy in hardware, etc), use the
1507 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1509 * After successfully changing clk's parent clk_set_parent will update the
1510 * clk topology, sysfs topology and propagate rate recalculation via
1511 * __clk_recalc_rates.
1513 * Returns 0 on success, -EERROR otherwise.
1515 int clk_set_parent(struct clk *clk, struct clk *parent)
1519 unsigned long p_rate = 0;
1521 if (!clk || !clk->ops)
1524 /* verify ops for for multi-parent clks */
1525 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1528 /* prevent racing with updates to the clock topology */
1531 if (clk->parent == parent)
1534 /* check that we are allowed to re-parent if the clock is in use */
1535 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1540 /* try finding the new parent index */
1542 p_index = clk_fetch_parent_index(clk, parent);
1543 p_rate = parent->rate;
1544 if (p_index == clk->num_parents) {
1545 pr_debug("%s: clk %s can not be parent of clk %s\n",
1546 __func__, parent->name, clk->name);
1552 /* propagate PRE_RATE_CHANGE notifications */
1553 ret = __clk_speculate_rates(clk, p_rate);
1555 /* abort if a driver objects */
1556 if (ret & NOTIFY_STOP_MASK)
1559 /* do the re-parent */
1560 ret = __clk_set_parent(clk, parent, p_index);
1562 /* propagate rate recalculation accordingly */
1564 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1566 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1569 clk_prepare_unlock();
1573 EXPORT_SYMBOL_GPL(clk_set_parent);
1576 * __clk_init - initialize the data structures in a struct clk
1577 * @dev: device initializing this clk, placeholder for now
1578 * @clk: clk being initialized
1580 * Initializes the lists in struct clk, queries the hardware for the
1581 * parent and rate and sets them both.
1583 int __clk_init(struct device *dev, struct clk *clk)
1587 struct hlist_node *tmp2;
1594 /* check to see if a clock with this name is already registered */
1595 if (__clk_lookup(clk->name)) {
1596 pr_debug("%s: clk %s already initialized\n",
1597 __func__, clk->name);
1602 /* check that clk_ops are sane. See Documentation/clk.txt */
1603 if (clk->ops->set_rate &&
1604 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1605 clk->ops->recalc_rate)) {
1606 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1607 __func__, clk->name);
1612 if (clk->ops->set_parent && !clk->ops->get_parent) {
1613 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1614 __func__, clk->name);
1619 /* throw a WARN if any entries in parent_names are NULL */
1620 for (i = 0; i < clk->num_parents; i++)
1621 WARN(!clk->parent_names[i],
1622 "%s: invalid NULL in %s's .parent_names\n",
1623 __func__, clk->name);
1626 * Allocate an array of struct clk *'s to avoid unnecessary string
1627 * look-ups of clk's possible parents. This can fail for clocks passed
1628 * in to clk_init during early boot; thus any access to clk->parents[]
1629 * must always check for a NULL pointer and try to populate it if
1632 * If clk->parents is not NULL we skip this entire block. This allows
1633 * for clock drivers to statically initialize clk->parents.
1635 if (clk->num_parents > 1 && !clk->parents) {
1636 clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1639 * __clk_lookup returns NULL for parents that have not been
1640 * clk_init'd; thus any access to clk->parents[] must check
1641 * for a NULL pointer. We can always perform lazy lookups for
1642 * missing parents later on.
1645 for (i = 0; i < clk->num_parents; i++)
1647 __clk_lookup(clk->parent_names[i]);
1650 clk->parent = __clk_init_parent(clk);
1653 * Populate clk->parent if parent has already been __clk_init'd. If
1654 * parent has not yet been __clk_init'd then place clk in the orphan
1655 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1658 * Every time a new clk is clk_init'd then we walk the list of orphan
1659 * clocks and re-parent any that are children of the clock currently
1663 hlist_add_head(&clk->child_node,
1664 &clk->parent->children);
1665 else if (clk->flags & CLK_IS_ROOT)
1666 hlist_add_head(&clk->child_node, &clk_root_list);
1668 hlist_add_head(&clk->child_node, &clk_orphan_list);
1671 * Set clk's rate. The preferred method is to use .recalc_rate. For
1672 * simple clocks and lazy developers the default fallback is to use the
1673 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1674 * then rate is set to zero.
1676 if (clk->ops->recalc_rate)
1677 clk->rate = clk->ops->recalc_rate(clk->hw,
1678 __clk_get_rate(clk->parent));
1679 else if (clk->parent)
1680 clk->rate = clk->parent->rate;
1685 * walk the list of orphan clocks and reparent any that are children of
1688 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1689 if (orphan->ops->get_parent) {
1690 i = orphan->ops->get_parent(orphan->hw);
1691 if (!strcmp(clk->name, orphan->parent_names[i]))
1692 __clk_reparent(orphan, clk);
1696 for (i = 0; i < orphan->num_parents; i++)
1697 if (!strcmp(clk->name, orphan->parent_names[i])) {
1698 __clk_reparent(orphan, clk);
1704 * optional platform-specific magic
1706 * The .init callback is not used by any of the basic clock types, but
1707 * exists for weird hardware that must perform initialization magic.
1708 * Please consider other ways of solving initialization problems before
1709 * using this callback, as its use is discouraged.
1712 clk->ops->init(clk->hw);
1714 clk_debug_register(clk);
1717 clk_prepare_unlock();
1723 * __clk_register - register a clock and return a cookie.
1725 * Same as clk_register, except that the .clk field inside hw shall point to a
1726 * preallocated (generally statically allocated) struct clk. None of the fields
1727 * of the struct clk need to be initialized.
1729 * The data pointed to by .init and .clk field shall NOT be marked as init
1732 * __clk_register is only exposed via clk-private.h and is intended for use with
1733 * very large numbers of clocks that need to be statically initialized. It is
1734 * a layering violation to include clk-private.h from any code which implements
1735 * a clock's .ops; as such any statically initialized clock data MUST be in a
1736 * separate C file from the logic that implements its operations. Returns 0
1737 * on success, otherwise an error code.
1739 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1745 clk->name = hw->init->name;
1746 clk->ops = hw->init->ops;
1748 clk->flags = hw->init->flags;
1749 clk->parent_names = hw->init->parent_names;
1750 clk->num_parents = hw->init->num_parents;
1752 ret = __clk_init(dev, clk);
1754 return ERR_PTR(ret);
1758 EXPORT_SYMBOL_GPL(__clk_register);
1760 static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
1764 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1766 pr_err("%s: could not allocate clk->name\n", __func__);
1770 clk->ops = hw->init->ops;
1772 clk->flags = hw->init->flags;
1773 clk->num_parents = hw->init->num_parents;
1776 /* allocate local copy in case parent_names is __initdata */
1777 clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents),
1780 if (!clk->parent_names) {
1781 pr_err("%s: could not allocate clk->parent_names\n", __func__);
1783 goto fail_parent_names;
1787 /* copy each string name in case parent_names is __initdata */
1788 for (i = 0; i < clk->num_parents; i++) {
1789 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1791 if (!clk->parent_names[i]) {
1792 pr_err("%s: could not copy parent_names\n", __func__);
1794 goto fail_parent_names_copy;
1798 ret = __clk_init(dev, clk);
1802 fail_parent_names_copy:
1804 kfree(clk->parent_names[i]);
1805 kfree(clk->parent_names);
1813 * clk_register - allocate a new clock, register it and return an opaque cookie
1814 * @dev: device that is registering this clock
1815 * @hw: link to hardware-specific clock data
1817 * clk_register is the primary interface for populating the clock tree with new
1818 * clock nodes. It returns a pointer to the newly allocated struct clk which
1819 * cannot be dereferenced by driver code but may be used in conjuction with the
1820 * rest of the clock API. In the event of an error clk_register will return an
1821 * error code; drivers must test for an error code after calling clk_register.
1823 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1828 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1830 pr_err("%s: could not allocate clk\n", __func__);
1835 ret = _clk_register(dev, hw, clk);
1841 return ERR_PTR(ret);
1843 EXPORT_SYMBOL_GPL(clk_register);
1846 * clk_unregister - unregister a currently registered clock
1847 * @clk: clock to unregister
1849 * Currently unimplemented.
1851 void clk_unregister(struct clk *clk) {}
1852 EXPORT_SYMBOL_GPL(clk_unregister);
1854 static void devm_clk_release(struct device *dev, void *res)
1856 clk_unregister(res);
1860 * devm_clk_register - resource managed clk_register()
1861 * @dev: device that is registering this clock
1862 * @hw: link to hardware-specific clock data
1864 * Managed clk_register(). Clocks returned from this function are
1865 * automatically clk_unregister()ed on driver detach. See clk_register() for
1868 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
1873 clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
1875 return ERR_PTR(-ENOMEM);
1877 ret = _clk_register(dev, hw, clk);
1879 devres_add(dev, clk);
1887 EXPORT_SYMBOL_GPL(devm_clk_register);
1889 static int devm_clk_match(struct device *dev, void *res, void *data)
1891 struct clk *c = res;
1898 * devm_clk_unregister - resource managed clk_unregister()
1899 * @clk: clock to unregister
1901 * Deallocate a clock allocated with devm_clk_register(). Normally
1902 * this function will not need to be called and the resource management
1903 * code will ensure that the resource is freed.
1905 void devm_clk_unregister(struct device *dev, struct clk *clk)
1907 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
1909 EXPORT_SYMBOL_GPL(devm_clk_unregister);
1911 /*** clk rate change notifiers ***/
1914 * clk_notifier_register - add a clk rate change notifier
1915 * @clk: struct clk * to watch
1916 * @nb: struct notifier_block * with callback info
1918 * Request notification when clk's rate changes. This uses an SRCU
1919 * notifier because we want it to block and notifier unregistrations are
1920 * uncommon. The callbacks associated with the notifier must not
1921 * re-enter into the clk framework by calling any top-level clk APIs;
1922 * this will cause a nested prepare_lock mutex.
1924 * Pre-change notifier callbacks will be passed the current, pre-change
1925 * rate of the clk via struct clk_notifier_data.old_rate. The new,
1926 * post-change rate of the clk is passed via struct
1927 * clk_notifier_data.new_rate.
1929 * Post-change notifiers will pass the now-current, post-change rate of
1930 * the clk in both struct clk_notifier_data.old_rate and struct
1931 * clk_notifier_data.new_rate.
1933 * Abort-change notifiers are effectively the opposite of pre-change
1934 * notifiers: the original pre-change clk rate is passed in via struct
1935 * clk_notifier_data.new_rate and the failed post-change rate is passed
1936 * in via struct clk_notifier_data.old_rate.
1938 * clk_notifier_register() must be called from non-atomic context.
1939 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1940 * allocation failure; otherwise, passes along the return value of
1941 * srcu_notifier_chain_register().
1943 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
1945 struct clk_notifier *cn;
1953 /* search the list of notifiers for this clk */
1954 list_for_each_entry(cn, &clk_notifier_list, node)
1958 /* if clk wasn't in the notifier list, allocate new clk_notifier */
1959 if (cn->clk != clk) {
1960 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
1965 srcu_init_notifier_head(&cn->notifier_head);
1967 list_add(&cn->node, &clk_notifier_list);
1970 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
1972 clk->notifier_count++;
1975 clk_prepare_unlock();
1979 EXPORT_SYMBOL_GPL(clk_notifier_register);
1982 * clk_notifier_unregister - remove a clk rate change notifier
1983 * @clk: struct clk *
1984 * @nb: struct notifier_block * with callback info
1986 * Request no further notification for changes to 'clk' and frees memory
1987 * allocated in clk_notifier_register.
1989 * Returns -EINVAL if called with null arguments; otherwise, passes
1990 * along the return value of srcu_notifier_chain_unregister().
1992 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
1994 struct clk_notifier *cn = NULL;
2002 list_for_each_entry(cn, &clk_notifier_list, node)
2006 if (cn->clk == clk) {
2007 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2009 clk->notifier_count--;
2011 /* XXX the notifier code should handle this better */
2012 if (!cn->notifier_head.head) {
2013 srcu_cleanup_notifier_head(&cn->notifier_head);
2014 list_del(&cn->node);
2022 clk_prepare_unlock();
2026 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2030 * struct of_clk_provider - Clock provider registration structure
2031 * @link: Entry in global list of clock providers
2032 * @node: Pointer to device tree node of clock provider
2033 * @get: Get clock callback. Returns NULL or a struct clk for the
2034 * given clock specifier
2035 * @data: context pointer to be passed into @get callback
2037 struct of_clk_provider {
2038 struct list_head link;
2040 struct device_node *node;
2041 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2045 extern struct of_device_id __clk_of_table[];
2047 static const struct of_device_id __clk_of_table_sentinel
2048 __used __section(__clk_of_table_end);
2050 static LIST_HEAD(of_clk_providers);
2051 static DEFINE_MUTEX(of_clk_lock);
2053 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2058 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2060 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2062 struct clk_onecell_data *clk_data = data;
2063 unsigned int idx = clkspec->args[0];
2065 if (idx >= clk_data->clk_num) {
2066 pr_err("%s: invalid clock index %d\n", __func__, idx);
2067 return ERR_PTR(-EINVAL);
2070 return clk_data->clks[idx];
2072 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2075 * of_clk_add_provider() - Register a clock provider for a node
2076 * @np: Device node pointer associated with clock provider
2077 * @clk_src_get: callback for decoding clock
2078 * @data: context pointer for @clk_src_get callback.
2080 int of_clk_add_provider(struct device_node *np,
2081 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2085 struct of_clk_provider *cp;
2087 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2091 cp->node = of_node_get(np);
2093 cp->get = clk_src_get;
2095 mutex_lock(&of_clk_lock);
2096 list_add(&cp->link, &of_clk_providers);
2097 mutex_unlock(&of_clk_lock);
2098 pr_debug("Added clock from %s\n", np->full_name);
2102 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2105 * of_clk_del_provider() - Remove a previously registered clock provider
2106 * @np: Device node pointer associated with clock provider
2108 void of_clk_del_provider(struct device_node *np)
2110 struct of_clk_provider *cp;
2112 mutex_lock(&of_clk_lock);
2113 list_for_each_entry(cp, &of_clk_providers, link) {
2114 if (cp->node == np) {
2115 list_del(&cp->link);
2116 of_node_put(cp->node);
2121 mutex_unlock(&of_clk_lock);
2123 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2125 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2127 struct of_clk_provider *provider;
2128 struct clk *clk = ERR_PTR(-ENOENT);
2130 /* Check if we have such a provider in our array */
2131 mutex_lock(&of_clk_lock);
2132 list_for_each_entry(provider, &of_clk_providers, link) {
2133 if (provider->node == clkspec->np)
2134 clk = provider->get(clkspec, provider->data);
2138 mutex_unlock(&of_clk_lock);
2143 const char *of_clk_get_parent_name(struct device_node *np, int index)
2145 struct of_phandle_args clkspec;
2146 const char *clk_name;
2152 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2157 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2158 clkspec.args_count ? clkspec.args[0] : 0,
2160 clk_name = clkspec.np->name;
2162 of_node_put(clkspec.np);
2165 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2168 * of_clk_init() - Scan and init clock providers from the DT
2169 * @matches: array of compatible values and init functions for providers.
2171 * This function scans the device tree for matching clock providers and
2172 * calls their initialization functions
2174 void __init of_clk_init(const struct of_device_id *matches)
2176 struct device_node *np;
2179 matches = __clk_of_table;
2181 for_each_matching_node(np, matches) {
2182 const struct of_device_id *match = of_match_node(matches, np);
2183 of_clk_init_cb_t clk_init_cb = match->data;