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-provider.h>
13 #include <linux/clk/clk-conf.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/spinlock.h>
17 #include <linux/err.h>
18 #include <linux/list.h>
19 #include <linux/slab.h>
21 #include <linux/device.h>
22 #include <linux/init.h>
23 #include <linux/sched.h>
27 static DEFINE_SPINLOCK(enable_lock);
28 static DEFINE_MUTEX(prepare_lock);
30 static struct task_struct *prepare_owner;
31 static struct task_struct *enable_owner;
33 static int prepare_refcnt;
34 static int enable_refcnt;
36 static HLIST_HEAD(clk_root_list);
37 static HLIST_HEAD(clk_orphan_list);
38 static LIST_HEAD(clk_notifier_list);
40 static long clk_core_get_accuracy(struct clk_core *clk);
41 static unsigned long clk_core_get_rate(struct clk_core *clk);
42 static int clk_core_get_phase(struct clk_core *clk);
43 static bool clk_core_is_prepared(struct clk_core *clk);
44 static bool clk_core_is_enabled(struct clk_core *clk);
45 static struct clk_core *clk_core_lookup(const char *name);
47 /*** private data structures ***/
51 const struct clk_ops *ops;
54 struct clk_core *parent;
55 const char **parent_names;
56 struct clk_core **parents;
60 unsigned long req_rate;
61 unsigned long new_rate;
62 struct clk_core *new_parent;
63 struct clk_core *new_child;
65 unsigned int enable_count;
66 unsigned int prepare_count;
67 unsigned long accuracy;
69 struct hlist_head children;
70 struct hlist_node child_node;
71 struct hlist_node debug_node;
72 struct hlist_head clks;
73 unsigned int notifier_count;
74 #ifdef CONFIG_DEBUG_FS
75 struct dentry *dentry;
80 #define CREATE_TRACE_POINTS
81 #include <trace/events/clk.h>
84 struct clk_core *core;
87 unsigned long min_rate;
88 unsigned long max_rate;
89 struct hlist_node child_node;
93 static void clk_prepare_lock(void)
95 if (!mutex_trylock(&prepare_lock)) {
96 if (prepare_owner == current) {
100 mutex_lock(&prepare_lock);
102 WARN_ON_ONCE(prepare_owner != NULL);
103 WARN_ON_ONCE(prepare_refcnt != 0);
104 prepare_owner = current;
108 static void clk_prepare_unlock(void)
110 WARN_ON_ONCE(prepare_owner != current);
111 WARN_ON_ONCE(prepare_refcnt == 0);
113 if (--prepare_refcnt)
115 prepare_owner = NULL;
116 mutex_unlock(&prepare_lock);
119 static unsigned long clk_enable_lock(void)
123 if (!spin_trylock_irqsave(&enable_lock, flags)) {
124 if (enable_owner == current) {
128 spin_lock_irqsave(&enable_lock, flags);
130 WARN_ON_ONCE(enable_owner != NULL);
131 WARN_ON_ONCE(enable_refcnt != 0);
132 enable_owner = current;
137 static void clk_enable_unlock(unsigned long flags)
139 WARN_ON_ONCE(enable_owner != current);
140 WARN_ON_ONCE(enable_refcnt == 0);
145 spin_unlock_irqrestore(&enable_lock, flags);
148 /*** debugfs support ***/
150 #ifdef CONFIG_DEBUG_FS
151 #include <linux/debugfs.h>
153 static struct dentry *rootdir;
154 static int inited = 0;
155 static DEFINE_MUTEX(clk_debug_lock);
156 static HLIST_HEAD(clk_debug_list);
158 static struct hlist_head *all_lists[] = {
164 static struct hlist_head *orphan_list[] = {
169 static void clk_summary_show_one(struct seq_file *s, struct clk_core *c,
175 seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
177 30 - level * 3, c->name,
178 c->enable_count, c->prepare_count, clk_core_get_rate(c),
179 clk_core_get_accuracy(c), clk_core_get_phase(c));
182 static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c,
185 struct clk_core *child;
190 clk_summary_show_one(s, c, level);
192 hlist_for_each_entry(child, &c->children, child_node)
193 clk_summary_show_subtree(s, child, level + 1);
196 static int clk_summary_show(struct seq_file *s, void *data)
199 struct hlist_head **lists = (struct hlist_head **)s->private;
201 seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy phase\n");
202 seq_puts(s, "----------------------------------------------------------------------------------------\n");
206 for (; *lists; lists++)
207 hlist_for_each_entry(c, *lists, child_node)
208 clk_summary_show_subtree(s, c, 0);
210 clk_prepare_unlock();
216 static int clk_summary_open(struct inode *inode, struct file *file)
218 return single_open(file, clk_summary_show, inode->i_private);
221 static const struct file_operations clk_summary_fops = {
222 .open = clk_summary_open,
225 .release = single_release,
228 static void clk_dump_one(struct seq_file *s, struct clk_core *c, int level)
233 seq_printf(s, "\"%s\": { ", c->name);
234 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
235 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
236 seq_printf(s, "\"rate\": %lu", clk_core_get_rate(c));
237 seq_printf(s, "\"accuracy\": %lu", clk_core_get_accuracy(c));
238 seq_printf(s, "\"phase\": %d", clk_core_get_phase(c));
241 static void clk_dump_subtree(struct seq_file *s, struct clk_core *c, int level)
243 struct clk_core *child;
248 clk_dump_one(s, c, level);
250 hlist_for_each_entry(child, &c->children, child_node) {
252 clk_dump_subtree(s, child, level + 1);
258 static int clk_dump(struct seq_file *s, void *data)
261 bool first_node = true;
262 struct hlist_head **lists = (struct hlist_head **)s->private;
268 for (; *lists; lists++) {
269 hlist_for_each_entry(c, *lists, child_node) {
273 clk_dump_subtree(s, c, 0);
277 clk_prepare_unlock();
284 static int clk_dump_open(struct inode *inode, struct file *file)
286 return single_open(file, clk_dump, inode->i_private);
289 static const struct file_operations clk_dump_fops = {
290 .open = clk_dump_open,
293 .release = single_release,
296 static int clk_debug_create_one(struct clk_core *clk, struct dentry *pdentry)
301 if (!clk || !pdentry) {
306 d = debugfs_create_dir(clk->name, pdentry);
312 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
317 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
318 (u32 *)&clk->accuracy);
322 d = debugfs_create_u32("clk_phase", S_IRUGO, clk->dentry,
327 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
332 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
333 (u32 *)&clk->prepare_count);
337 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
338 (u32 *)&clk->enable_count);
342 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
343 (u32 *)&clk->notifier_count);
347 if (clk->ops->debug_init) {
348 ret = clk->ops->debug_init(clk->hw, clk->dentry);
357 debugfs_remove_recursive(clk->dentry);
364 * clk_debug_register - add a clk node to the debugfs clk tree
365 * @clk: the clk being added to the debugfs clk tree
367 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
368 * initialized. Otherwise it bails out early since the debugfs clk tree
369 * will be created lazily by clk_debug_init as part of a late_initcall.
371 static int clk_debug_register(struct clk_core *clk)
375 mutex_lock(&clk_debug_lock);
376 hlist_add_head(&clk->debug_node, &clk_debug_list);
381 ret = clk_debug_create_one(clk, rootdir);
383 mutex_unlock(&clk_debug_lock);
389 * clk_debug_unregister - remove a clk node from the debugfs clk tree
390 * @clk: the clk being removed from the debugfs clk tree
392 * Dynamically removes a clk and all it's children clk nodes from the
393 * debugfs clk tree if clk->dentry points to debugfs created by
394 * clk_debug_register in __clk_init.
396 static void clk_debug_unregister(struct clk_core *clk)
398 mutex_lock(&clk_debug_lock);
399 hlist_del_init(&clk->debug_node);
400 debugfs_remove_recursive(clk->dentry);
402 mutex_unlock(&clk_debug_lock);
405 struct dentry *clk_debugfs_add_file(struct clk_hw *hw, char *name, umode_t mode,
406 void *data, const struct file_operations *fops)
408 struct dentry *d = NULL;
410 if (hw->core->dentry)
411 d = debugfs_create_file(name, mode, hw->core->dentry, data,
416 EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
419 * clk_debug_init - lazily create the debugfs clk tree visualization
421 * clks are often initialized very early during boot before memory can
422 * be dynamically allocated and well before debugfs is setup.
423 * clk_debug_init walks the clk tree hierarchy while holding
424 * prepare_lock and creates the topology as part of a late_initcall,
425 * thus insuring that clks initialized very early will still be
426 * represented in the debugfs clk tree. This function should only be
427 * called once at boot-time, and all other clks added dynamically will
428 * be done so with clk_debug_register.
430 static int __init clk_debug_init(void)
432 struct clk_core *clk;
435 rootdir = debugfs_create_dir("clk", NULL);
440 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists,
445 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists,
450 d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir,
451 &orphan_list, &clk_summary_fops);
455 d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir,
456 &orphan_list, &clk_dump_fops);
460 mutex_lock(&clk_debug_lock);
461 hlist_for_each_entry(clk, &clk_debug_list, debug_node)
462 clk_debug_create_one(clk, rootdir);
465 mutex_unlock(&clk_debug_lock);
469 late_initcall(clk_debug_init);
471 static inline int clk_debug_register(struct clk_core *clk) { return 0; }
472 static inline void clk_debug_reparent(struct clk_core *clk,
473 struct clk_core *new_parent)
476 static inline void clk_debug_unregister(struct clk_core *clk)
481 /* caller must hold prepare_lock */
482 static void clk_unprepare_unused_subtree(struct clk_core *clk)
484 struct clk_core *child;
486 lockdep_assert_held(&prepare_lock);
488 hlist_for_each_entry(child, &clk->children, child_node)
489 clk_unprepare_unused_subtree(child);
491 if (clk->prepare_count)
494 if (clk->flags & CLK_IGNORE_UNUSED)
497 if (clk_core_is_prepared(clk)) {
498 trace_clk_unprepare(clk);
499 if (clk->ops->unprepare_unused)
500 clk->ops->unprepare_unused(clk->hw);
501 else if (clk->ops->unprepare)
502 clk->ops->unprepare(clk->hw);
503 trace_clk_unprepare_complete(clk);
507 /* caller must hold prepare_lock */
508 static void clk_disable_unused_subtree(struct clk_core *clk)
510 struct clk_core *child;
513 lockdep_assert_held(&prepare_lock);
515 hlist_for_each_entry(child, &clk->children, child_node)
516 clk_disable_unused_subtree(child);
518 flags = clk_enable_lock();
520 if (clk->enable_count)
523 if (clk->flags & CLK_IGNORE_UNUSED)
527 * some gate clocks have special needs during the disable-unused
528 * sequence. call .disable_unused if available, otherwise fall
531 if (clk_core_is_enabled(clk)) {
532 trace_clk_disable(clk);
533 if (clk->ops->disable_unused)
534 clk->ops->disable_unused(clk->hw);
535 else if (clk->ops->disable)
536 clk->ops->disable(clk->hw);
537 trace_clk_disable_complete(clk);
541 clk_enable_unlock(flags);
544 static bool clk_ignore_unused;
545 static int __init clk_ignore_unused_setup(char *__unused)
547 clk_ignore_unused = true;
550 __setup("clk_ignore_unused", clk_ignore_unused_setup);
552 static int clk_disable_unused(void)
554 struct clk_core *clk;
556 if (clk_ignore_unused) {
557 pr_warn("clk: Not disabling unused clocks\n");
563 hlist_for_each_entry(clk, &clk_root_list, child_node)
564 clk_disable_unused_subtree(clk);
566 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
567 clk_disable_unused_subtree(clk);
569 hlist_for_each_entry(clk, &clk_root_list, child_node)
570 clk_unprepare_unused_subtree(clk);
572 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
573 clk_unprepare_unused_subtree(clk);
575 clk_prepare_unlock();
579 late_initcall_sync(clk_disable_unused);
581 /*** helper functions ***/
583 const char *__clk_get_name(struct clk *clk)
585 return !clk ? NULL : clk->core->name;
587 EXPORT_SYMBOL_GPL(__clk_get_name);
589 struct clk_hw *__clk_get_hw(struct clk *clk)
591 return !clk ? NULL : clk->core->hw;
593 EXPORT_SYMBOL_GPL(__clk_get_hw);
595 u8 __clk_get_num_parents(struct clk *clk)
597 return !clk ? 0 : clk->core->num_parents;
599 EXPORT_SYMBOL_GPL(__clk_get_num_parents);
601 struct clk *__clk_get_parent(struct clk *clk)
606 /* TODO: Create a per-user clk and change callers to call clk_put */
607 return !clk->core->parent ? NULL : clk->core->parent->hw->clk;
609 EXPORT_SYMBOL_GPL(__clk_get_parent);
611 static struct clk_core *clk_core_get_parent_by_index(struct clk_core *clk,
614 if (!clk || index >= clk->num_parents)
616 else if (!clk->parents)
617 return clk_core_lookup(clk->parent_names[index]);
618 else if (!clk->parents[index])
619 return clk->parents[index] =
620 clk_core_lookup(clk->parent_names[index]);
622 return clk->parents[index];
625 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
627 struct clk_core *parent;
632 parent = clk_core_get_parent_by_index(clk->core, index);
634 return !parent ? NULL : parent->hw->clk;
636 EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
638 unsigned int __clk_get_enable_count(struct clk *clk)
640 return !clk ? 0 : clk->core->enable_count;
643 static unsigned long clk_core_get_rate_nolock(struct clk_core *clk)
654 if (clk->flags & CLK_IS_ROOT)
664 unsigned long __clk_get_rate(struct clk *clk)
669 return clk_core_get_rate_nolock(clk->core);
671 EXPORT_SYMBOL_GPL(__clk_get_rate);
673 static unsigned long __clk_get_accuracy(struct clk_core *clk)
678 return clk->accuracy;
681 unsigned long __clk_get_flags(struct clk *clk)
683 return !clk ? 0 : clk->core->flags;
685 EXPORT_SYMBOL_GPL(__clk_get_flags);
687 static bool clk_core_is_prepared(struct clk_core *clk)
695 * .is_prepared is optional for clocks that can prepare
696 * fall back to software usage counter if it is missing
698 if (!clk->ops->is_prepared) {
699 ret = clk->prepare_count ? 1 : 0;
703 ret = clk->ops->is_prepared(clk->hw);
708 bool __clk_is_prepared(struct clk *clk)
713 return clk_core_is_prepared(clk->core);
716 static bool clk_core_is_enabled(struct clk_core *clk)
724 * .is_enabled is only mandatory for clocks that gate
725 * fall back to software usage counter if .is_enabled is missing
727 if (!clk->ops->is_enabled) {
728 ret = clk->enable_count ? 1 : 0;
732 ret = clk->ops->is_enabled(clk->hw);
737 bool __clk_is_enabled(struct clk *clk)
742 return clk_core_is_enabled(clk->core);
744 EXPORT_SYMBOL_GPL(__clk_is_enabled);
746 static struct clk_core *__clk_lookup_subtree(const char *name,
747 struct clk_core *clk)
749 struct clk_core *child;
750 struct clk_core *ret;
752 if (!strcmp(clk->name, name))
755 hlist_for_each_entry(child, &clk->children, child_node) {
756 ret = __clk_lookup_subtree(name, child);
764 static struct clk_core *clk_core_lookup(const char *name)
766 struct clk_core *root_clk;
767 struct clk_core *ret;
772 /* search the 'proper' clk tree first */
773 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
774 ret = __clk_lookup_subtree(name, root_clk);
779 /* if not found, then search the orphan tree */
780 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
781 ret = __clk_lookup_subtree(name, root_clk);
789 static bool mux_is_better_rate(unsigned long rate, unsigned long now,
790 unsigned long best, unsigned long flags)
792 if (flags & CLK_MUX_ROUND_CLOSEST)
793 return abs(now - rate) < abs(best - rate);
795 return now <= rate && now > best;
799 clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate,
800 unsigned long min_rate,
801 unsigned long max_rate,
802 unsigned long *best_parent_rate,
803 struct clk_hw **best_parent_p,
806 struct clk_core *core = hw->core, *parent, *best_parent = NULL;
808 unsigned long parent_rate, best = 0;
810 /* if NO_REPARENT flag set, pass through to current parent */
811 if (core->flags & CLK_SET_RATE_NO_REPARENT) {
812 parent = core->parent;
813 if (core->flags & CLK_SET_RATE_PARENT)
814 best = __clk_determine_rate(parent ? parent->hw : NULL,
815 rate, min_rate, max_rate);
817 best = clk_core_get_rate_nolock(parent);
819 best = clk_core_get_rate_nolock(core);
823 /* find the parent that can provide the fastest rate <= rate */
824 num_parents = core->num_parents;
825 for (i = 0; i < num_parents; i++) {
826 parent = clk_core_get_parent_by_index(core, i);
829 if (core->flags & CLK_SET_RATE_PARENT)
830 parent_rate = __clk_determine_rate(parent->hw, rate,
834 parent_rate = clk_core_get_rate_nolock(parent);
835 if (mux_is_better_rate(rate, parent_rate, best, flags)) {
836 best_parent = parent;
843 *best_parent_p = best_parent->hw;
844 *best_parent_rate = best;
849 struct clk *__clk_lookup(const char *name)
851 struct clk_core *core = clk_core_lookup(name);
853 return !core ? NULL : core->hw->clk;
856 static void clk_core_get_boundaries(struct clk_core *clk,
857 unsigned long *min_rate,
858 unsigned long *max_rate)
860 struct clk *clk_user;
863 *max_rate = ULONG_MAX;
865 hlist_for_each_entry(clk_user, &clk->clks, child_node)
866 *min_rate = max(*min_rate, clk_user->min_rate);
868 hlist_for_each_entry(clk_user, &clk->clks, child_node)
869 *max_rate = min(*max_rate, clk_user->max_rate);
873 * Helper for finding best parent to provide a given frequency. This can be used
874 * directly as a determine_rate callback (e.g. for a mux), or from a more
875 * complex clock that may combine a mux with other operations.
877 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
878 unsigned long min_rate,
879 unsigned long max_rate,
880 unsigned long *best_parent_rate,
881 struct clk_hw **best_parent_p)
883 return clk_mux_determine_rate_flags(hw, rate, min_rate, max_rate,
887 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
889 long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
890 unsigned long min_rate,
891 unsigned long max_rate,
892 unsigned long *best_parent_rate,
893 struct clk_hw **best_parent_p)
895 return clk_mux_determine_rate_flags(hw, rate, min_rate, max_rate,
898 CLK_MUX_ROUND_CLOSEST);
900 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
904 static void clk_core_unprepare(struct clk_core *clk)
909 if (WARN_ON(clk->prepare_count == 0))
912 if (--clk->prepare_count > 0)
915 WARN_ON(clk->enable_count > 0);
917 trace_clk_unprepare(clk);
919 if (clk->ops->unprepare)
920 clk->ops->unprepare(clk->hw);
922 trace_clk_unprepare_complete(clk);
923 clk_core_unprepare(clk->parent);
927 * clk_unprepare - undo preparation of a clock source
928 * @clk: the clk being unprepared
930 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
931 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
932 * if the operation may sleep. One example is a clk which is accessed over
933 * I2c. In the complex case a clk gate operation may require a fast and a slow
934 * part. It is this reason that clk_unprepare and clk_disable are not mutually
935 * exclusive. In fact clk_disable must be called before clk_unprepare.
937 void clk_unprepare(struct clk *clk)
939 if (IS_ERR_OR_NULL(clk))
943 clk_core_unprepare(clk->core);
944 clk_prepare_unlock();
946 EXPORT_SYMBOL_GPL(clk_unprepare);
948 static int clk_core_prepare(struct clk_core *clk)
955 if (clk->prepare_count == 0) {
956 ret = clk_core_prepare(clk->parent);
960 trace_clk_prepare(clk);
962 if (clk->ops->prepare)
963 ret = clk->ops->prepare(clk->hw);
965 trace_clk_prepare_complete(clk);
968 clk_core_unprepare(clk->parent);
973 clk->prepare_count++;
979 * clk_prepare - prepare a clock source
980 * @clk: the clk being prepared
982 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
983 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
984 * operation may sleep. One example is a clk which is accessed over I2c. In
985 * the complex case a clk ungate operation may require a fast and a slow part.
986 * It is this reason that clk_prepare and clk_enable are not mutually
987 * exclusive. In fact clk_prepare must be called before clk_enable.
988 * Returns 0 on success, -EERROR otherwise.
990 int clk_prepare(struct clk *clk)
998 ret = clk_core_prepare(clk->core);
999 clk_prepare_unlock();
1003 EXPORT_SYMBOL_GPL(clk_prepare);
1005 static void clk_core_disable(struct clk_core *clk)
1010 if (WARN_ON(clk->enable_count == 0))
1013 if (--clk->enable_count > 0)
1016 trace_clk_disable(clk);
1018 if (clk->ops->disable)
1019 clk->ops->disable(clk->hw);
1021 trace_clk_disable_complete(clk);
1023 clk_core_disable(clk->parent);
1026 static void __clk_disable(struct clk *clk)
1031 clk_core_disable(clk->core);
1035 * clk_disable - gate a clock
1036 * @clk: the clk being gated
1038 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
1039 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
1040 * clk if the operation is fast and will never sleep. One example is a
1041 * SoC-internal clk which is controlled via simple register writes. In the
1042 * complex case a clk gate operation may require a fast and a slow part. It is
1043 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
1044 * In fact clk_disable must be called before clk_unprepare.
1046 void clk_disable(struct clk *clk)
1048 unsigned long flags;
1050 if (IS_ERR_OR_NULL(clk))
1053 flags = clk_enable_lock();
1055 clk_enable_unlock(flags);
1057 EXPORT_SYMBOL_GPL(clk_disable);
1059 static int clk_core_enable(struct clk_core *clk)
1066 if (WARN_ON(clk->prepare_count == 0))
1069 if (clk->enable_count == 0) {
1070 ret = clk_core_enable(clk->parent);
1075 trace_clk_enable(clk);
1077 if (clk->ops->enable)
1078 ret = clk->ops->enable(clk->hw);
1080 trace_clk_enable_complete(clk);
1083 clk_core_disable(clk->parent);
1088 clk->enable_count++;
1092 static int __clk_enable(struct clk *clk)
1097 return clk_core_enable(clk->core);
1101 * clk_enable - ungate a clock
1102 * @clk: the clk being ungated
1104 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
1105 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
1106 * if the operation will never sleep. One example is a SoC-internal clk which
1107 * is controlled via simple register writes. In the complex case a clk ungate
1108 * operation may require a fast and a slow part. It is this reason that
1109 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
1110 * must be called before clk_enable. Returns 0 on success, -EERROR
1113 int clk_enable(struct clk *clk)
1115 unsigned long flags;
1118 flags = clk_enable_lock();
1119 ret = __clk_enable(clk);
1120 clk_enable_unlock(flags);
1124 EXPORT_SYMBOL_GPL(clk_enable);
1126 static unsigned long clk_core_round_rate_nolock(struct clk_core *clk,
1128 unsigned long min_rate,
1129 unsigned long max_rate)
1131 unsigned long parent_rate = 0;
1132 struct clk_core *parent;
1133 struct clk_hw *parent_hw;
1135 lockdep_assert_held(&prepare_lock);
1140 parent = clk->parent;
1142 parent_rate = parent->rate;
1144 if (clk->ops->determine_rate) {
1145 parent_hw = parent ? parent->hw : NULL;
1146 return clk->ops->determine_rate(clk->hw, rate,
1148 &parent_rate, &parent_hw);
1149 } else if (clk->ops->round_rate)
1150 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
1151 else if (clk->flags & CLK_SET_RATE_PARENT)
1152 return clk_core_round_rate_nolock(clk->parent, rate, min_rate,
1159 * __clk_determine_rate - get the closest rate actually supported by a clock
1160 * @hw: determine the rate of this clock
1161 * @rate: target rate
1162 * @min_rate: returned rate must be greater than this rate
1163 * @max_rate: returned rate must be less than this rate
1165 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate and
1168 unsigned long __clk_determine_rate(struct clk_hw *hw,
1170 unsigned long min_rate,
1171 unsigned long max_rate)
1176 return clk_core_round_rate_nolock(hw->core, rate, min_rate, max_rate);
1178 EXPORT_SYMBOL_GPL(__clk_determine_rate);
1181 * __clk_round_rate - round the given rate for a clk
1182 * @clk: round the rate of this clock
1183 * @rate: the rate which is to be rounded
1185 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
1187 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
1189 unsigned long min_rate;
1190 unsigned long max_rate;
1195 clk_core_get_boundaries(clk->core, &min_rate, &max_rate);
1197 return clk_core_round_rate_nolock(clk->core, rate, min_rate, max_rate);
1199 EXPORT_SYMBOL_GPL(__clk_round_rate);
1202 * clk_round_rate - round the given rate for a clk
1203 * @clk: the clk for which we are rounding a rate
1204 * @rate: the rate which is to be rounded
1206 * Takes in a rate as input and rounds it to a rate that the clk can actually
1207 * use which is then returned. If clk doesn't support round_rate operation
1208 * then the parent rate is returned.
1210 long clk_round_rate(struct clk *clk, unsigned long rate)
1218 ret = __clk_round_rate(clk, rate);
1219 clk_prepare_unlock();
1223 EXPORT_SYMBOL_GPL(clk_round_rate);
1226 * __clk_notify - call clk notifier chain
1227 * @clk: struct clk * that is changing rate
1228 * @msg: clk notifier type (see include/linux/clk.h)
1229 * @old_rate: old clk rate
1230 * @new_rate: new clk rate
1232 * Triggers a notifier call chain on the clk rate-change notification
1233 * for 'clk'. Passes a pointer to the struct clk and the previous
1234 * and current rates to the notifier callback. Intended to be called by
1235 * internal clock code only. Returns NOTIFY_DONE from the last driver
1236 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1237 * a driver returns that.
1239 static int __clk_notify(struct clk_core *clk, unsigned long msg,
1240 unsigned long old_rate, unsigned long new_rate)
1242 struct clk_notifier *cn;
1243 struct clk_notifier_data cnd;
1244 int ret = NOTIFY_DONE;
1246 cnd.old_rate = old_rate;
1247 cnd.new_rate = new_rate;
1249 list_for_each_entry(cn, &clk_notifier_list, node) {
1250 if (cn->clk->core == clk) {
1252 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1261 * __clk_recalc_accuracies
1262 * @clk: first clk in the subtree
1264 * Walks the subtree of clks starting with clk and recalculates accuracies as
1265 * it goes. Note that if a clk does not implement the .recalc_accuracy
1266 * callback then it is assumed that the clock will take on the accuracy of it's
1269 * Caller must hold prepare_lock.
1271 static void __clk_recalc_accuracies(struct clk_core *clk)
1273 unsigned long parent_accuracy = 0;
1274 struct clk_core *child;
1276 lockdep_assert_held(&prepare_lock);
1279 parent_accuracy = clk->parent->accuracy;
1281 if (clk->ops->recalc_accuracy)
1282 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1285 clk->accuracy = parent_accuracy;
1287 hlist_for_each_entry(child, &clk->children, child_node)
1288 __clk_recalc_accuracies(child);
1291 static long clk_core_get_accuracy(struct clk_core *clk)
1293 unsigned long accuracy;
1296 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1297 __clk_recalc_accuracies(clk);
1299 accuracy = __clk_get_accuracy(clk);
1300 clk_prepare_unlock();
1306 * clk_get_accuracy - return the accuracy of clk
1307 * @clk: the clk whose accuracy is being returned
1309 * Simply returns the cached accuracy of the clk, unless
1310 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1312 * If clk is NULL then returns 0.
1314 long clk_get_accuracy(struct clk *clk)
1319 return clk_core_get_accuracy(clk->core);
1321 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1323 static unsigned long clk_recalc(struct clk_core *clk,
1324 unsigned long parent_rate)
1326 if (clk->ops->recalc_rate)
1327 return clk->ops->recalc_rate(clk->hw, parent_rate);
1332 * __clk_recalc_rates
1333 * @clk: first clk in the subtree
1334 * @msg: notification type (see include/linux/clk.h)
1336 * Walks the subtree of clks starting with clk and recalculates rates as it
1337 * goes. Note that if a clk does not implement the .recalc_rate callback then
1338 * it is assumed that the clock will take on the rate of its parent.
1340 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1343 * Caller must hold prepare_lock.
1345 static void __clk_recalc_rates(struct clk_core *clk, unsigned long msg)
1347 unsigned long old_rate;
1348 unsigned long parent_rate = 0;
1349 struct clk_core *child;
1351 lockdep_assert_held(&prepare_lock);
1353 old_rate = clk->rate;
1356 parent_rate = clk->parent->rate;
1358 clk->rate = clk_recalc(clk, parent_rate);
1361 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1362 * & ABORT_RATE_CHANGE notifiers
1364 if (clk->notifier_count && msg)
1365 __clk_notify(clk, msg, old_rate, clk->rate);
1367 hlist_for_each_entry(child, &clk->children, child_node)
1368 __clk_recalc_rates(child, msg);
1371 static unsigned long clk_core_get_rate(struct clk_core *clk)
1377 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1378 __clk_recalc_rates(clk, 0);
1380 rate = clk_core_get_rate_nolock(clk);
1381 clk_prepare_unlock();
1385 EXPORT_SYMBOL_GPL(clk_core_get_rate);
1388 * clk_get_rate - return the rate of clk
1389 * @clk: the clk whose rate is being returned
1391 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1392 * is set, which means a recalc_rate will be issued.
1393 * If clk is NULL then returns 0.
1395 unsigned long clk_get_rate(struct clk *clk)
1400 return clk_core_get_rate(clk->core);
1402 EXPORT_SYMBOL_GPL(clk_get_rate);
1404 static int clk_fetch_parent_index(struct clk_core *clk,
1405 struct clk_core *parent)
1409 if (!clk->parents) {
1410 clk->parents = kcalloc(clk->num_parents,
1411 sizeof(struct clk *), GFP_KERNEL);
1417 * find index of new parent clock using cached parent ptrs,
1418 * or if not yet cached, use string name comparison and cache
1419 * them now to avoid future calls to clk_core_lookup.
1421 for (i = 0; i < clk->num_parents; i++) {
1422 if (clk->parents[i] == parent)
1425 if (clk->parents[i])
1428 if (!strcmp(clk->parent_names[i], parent->name)) {
1429 clk->parents[i] = clk_core_lookup(parent->name);
1437 static void clk_reparent(struct clk_core *clk, struct clk_core *new_parent)
1439 hlist_del(&clk->child_node);
1442 /* avoid duplicate POST_RATE_CHANGE notifications */
1443 if (new_parent->new_child == clk)
1444 new_parent->new_child = NULL;
1446 hlist_add_head(&clk->child_node, &new_parent->children);
1448 hlist_add_head(&clk->child_node, &clk_orphan_list);
1451 clk->parent = new_parent;
1454 static struct clk_core *__clk_set_parent_before(struct clk_core *clk,
1455 struct clk_core *parent)
1457 unsigned long flags;
1458 struct clk_core *old_parent = clk->parent;
1461 * Migrate prepare state between parents and prevent race with
1464 * If the clock is not prepared, then a race with
1465 * clk_enable/disable() is impossible since we already have the
1466 * prepare lock (future calls to clk_enable() need to be preceded by
1469 * If the clock is prepared, migrate the prepared state to the new
1470 * parent and also protect against a race with clk_enable() by
1471 * forcing the clock and the new parent on. This ensures that all
1472 * future calls to clk_enable() are practically NOPs with respect to
1473 * hardware and software states.
1475 * See also: Comment for clk_set_parent() below.
1477 if (clk->prepare_count) {
1478 clk_core_prepare(parent);
1479 clk_core_enable(parent);
1480 clk_core_enable(clk);
1483 /* update the clk tree topology */
1484 flags = clk_enable_lock();
1485 clk_reparent(clk, parent);
1486 clk_enable_unlock(flags);
1491 static void __clk_set_parent_after(struct clk_core *core,
1492 struct clk_core *parent,
1493 struct clk_core *old_parent)
1496 * Finish the migration of prepare state and undo the changes done
1497 * for preventing a race with clk_enable().
1499 if (core->prepare_count) {
1500 clk_core_disable(core);
1501 clk_core_disable(old_parent);
1502 clk_core_unprepare(old_parent);
1506 static int __clk_set_parent(struct clk_core *clk, struct clk_core *parent,
1509 unsigned long flags;
1511 struct clk_core *old_parent;
1513 old_parent = __clk_set_parent_before(clk, parent);
1515 trace_clk_set_parent(clk, parent);
1517 /* change clock input source */
1518 if (parent && clk->ops->set_parent)
1519 ret = clk->ops->set_parent(clk->hw, p_index);
1521 trace_clk_set_parent_complete(clk, parent);
1524 flags = clk_enable_lock();
1525 clk_reparent(clk, old_parent);
1526 clk_enable_unlock(flags);
1528 if (clk->prepare_count) {
1529 clk_core_disable(clk);
1530 clk_core_disable(parent);
1531 clk_core_unprepare(parent);
1536 __clk_set_parent_after(clk, parent, old_parent);
1542 * __clk_speculate_rates
1543 * @clk: first clk in the subtree
1544 * @parent_rate: the "future" rate of clk's parent
1546 * Walks the subtree of clks starting with clk, speculating rates as it
1547 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1549 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1550 * pre-rate change notifications and returns early if no clks in the
1551 * subtree have subscribed to the notifications. Note that if a clk does not
1552 * implement the .recalc_rate callback then it is assumed that the clock will
1553 * take on the rate of its parent.
1555 * Caller must hold prepare_lock.
1557 static int __clk_speculate_rates(struct clk_core *clk,
1558 unsigned long parent_rate)
1560 struct clk_core *child;
1561 unsigned long new_rate;
1562 int ret = NOTIFY_DONE;
1564 lockdep_assert_held(&prepare_lock);
1566 new_rate = clk_recalc(clk, parent_rate);
1568 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1569 if (clk->notifier_count)
1570 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1572 if (ret & NOTIFY_STOP_MASK) {
1573 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1574 __func__, clk->name, ret);
1578 hlist_for_each_entry(child, &clk->children, child_node) {
1579 ret = __clk_speculate_rates(child, new_rate);
1580 if (ret & NOTIFY_STOP_MASK)
1588 static void clk_calc_subtree(struct clk_core *clk, unsigned long new_rate,
1589 struct clk_core *new_parent, u8 p_index)
1591 struct clk_core *child;
1593 clk->new_rate = new_rate;
1594 clk->new_parent = new_parent;
1595 clk->new_parent_index = p_index;
1596 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1597 clk->new_child = NULL;
1598 if (new_parent && new_parent != clk->parent)
1599 new_parent->new_child = clk;
1601 hlist_for_each_entry(child, &clk->children, child_node) {
1602 child->new_rate = clk_recalc(child, new_rate);
1603 clk_calc_subtree(child, child->new_rate, NULL, 0);
1608 * calculate the new rates returning the topmost clock that has to be
1611 static struct clk_core *clk_calc_new_rates(struct clk_core *clk,
1614 struct clk_core *top = clk;
1615 struct clk_core *old_parent, *parent;
1616 struct clk_hw *parent_hw;
1617 unsigned long best_parent_rate = 0;
1618 unsigned long new_rate;
1619 unsigned long min_rate;
1620 unsigned long max_rate;
1624 if (IS_ERR_OR_NULL(clk))
1627 /* save parent rate, if it exists */
1628 parent = old_parent = clk->parent;
1630 best_parent_rate = parent->rate;
1632 clk_core_get_boundaries(clk, &min_rate, &max_rate);
1634 /* find the closest rate and parent clk/rate */
1635 if (clk->ops->determine_rate) {
1636 parent_hw = parent ? parent->hw : NULL;
1637 new_rate = clk->ops->determine_rate(clk->hw, rate,
1642 parent = parent_hw ? parent_hw->core : NULL;
1643 } else if (clk->ops->round_rate) {
1644 new_rate = clk->ops->round_rate(clk->hw, rate,
1646 if (new_rate < min_rate || new_rate > max_rate)
1648 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1649 /* pass-through clock without adjustable parent */
1650 clk->new_rate = clk->rate;
1653 /* pass-through clock with adjustable parent */
1654 top = clk_calc_new_rates(parent, rate);
1655 new_rate = parent->new_rate;
1659 /* some clocks must be gated to change parent */
1660 if (parent != old_parent &&
1661 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1662 pr_debug("%s: %s not gated but wants to reparent\n",
1663 __func__, clk->name);
1667 /* try finding the new parent index */
1668 if (parent && clk->num_parents > 1) {
1669 p_index = clk_fetch_parent_index(clk, parent);
1671 pr_debug("%s: clk %s can not be parent of clk %s\n",
1672 __func__, parent->name, clk->name);
1677 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1678 best_parent_rate != parent->rate)
1679 top = clk_calc_new_rates(parent, best_parent_rate);
1682 clk_calc_subtree(clk, new_rate, parent, p_index);
1688 * Notify about rate changes in a subtree. Always walk down the whole tree
1689 * so that in case of an error we can walk down the whole tree again and
1692 static struct clk_core *clk_propagate_rate_change(struct clk_core *clk,
1693 unsigned long event)
1695 struct clk_core *child, *tmp_clk, *fail_clk = NULL;
1696 int ret = NOTIFY_DONE;
1698 if (clk->rate == clk->new_rate)
1701 if (clk->notifier_count) {
1702 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1703 if (ret & NOTIFY_STOP_MASK)
1707 hlist_for_each_entry(child, &clk->children, child_node) {
1708 /* Skip children who will be reparented to another clock */
1709 if (child->new_parent && child->new_parent != clk)
1711 tmp_clk = clk_propagate_rate_change(child, event);
1716 /* handle the new child who might not be in clk->children yet */
1717 if (clk->new_child) {
1718 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1727 * walk down a subtree and set the new rates notifying the rate
1730 static void clk_change_rate(struct clk_core *clk)
1732 struct clk_core *child;
1733 struct hlist_node *tmp;
1734 unsigned long old_rate;
1735 unsigned long best_parent_rate = 0;
1736 bool skip_set_rate = false;
1737 struct clk_core *old_parent;
1739 old_rate = clk->rate;
1741 if (clk->new_parent)
1742 best_parent_rate = clk->new_parent->rate;
1743 else if (clk->parent)
1744 best_parent_rate = clk->parent->rate;
1746 if (clk->new_parent && clk->new_parent != clk->parent) {
1747 old_parent = __clk_set_parent_before(clk, clk->new_parent);
1748 trace_clk_set_parent(clk, clk->new_parent);
1750 if (clk->ops->set_rate_and_parent) {
1751 skip_set_rate = true;
1752 clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
1754 clk->new_parent_index);
1755 } else if (clk->ops->set_parent) {
1756 clk->ops->set_parent(clk->hw, clk->new_parent_index);
1759 trace_clk_set_parent_complete(clk, clk->new_parent);
1760 __clk_set_parent_after(clk, clk->new_parent, old_parent);
1763 trace_clk_set_rate(clk, clk->new_rate);
1765 if (!skip_set_rate && clk->ops->set_rate)
1766 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1768 trace_clk_set_rate_complete(clk, clk->new_rate);
1770 clk->rate = clk_recalc(clk, best_parent_rate);
1772 if (clk->notifier_count && old_rate != clk->rate)
1773 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1776 * Use safe iteration, as change_rate can actually swap parents
1777 * for certain clock types.
1779 hlist_for_each_entry_safe(child, tmp, &clk->children, child_node) {
1780 /* Skip children who will be reparented to another clock */
1781 if (child->new_parent && child->new_parent != clk)
1783 clk_change_rate(child);
1786 /* handle the new child who might not be in clk->children yet */
1788 clk_change_rate(clk->new_child);
1791 static int clk_core_set_rate_nolock(struct clk_core *clk,
1792 unsigned long req_rate)
1794 struct clk_core *top, *fail_clk;
1795 unsigned long rate = req_rate;
1801 /* bail early if nothing to do */
1802 if (rate == clk_core_get_rate_nolock(clk))
1805 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count)
1808 /* calculate new rates and get the topmost changed clock */
1809 top = clk_calc_new_rates(clk, rate);
1813 /* notify that we are about to change rates */
1814 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1816 pr_debug("%s: failed to set %s rate\n", __func__,
1818 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1822 /* change the rates */
1823 clk_change_rate(top);
1825 clk->req_rate = req_rate;
1831 * clk_set_rate - specify a new rate for clk
1832 * @clk: the clk whose rate is being changed
1833 * @rate: the new rate for clk
1835 * In the simplest case clk_set_rate will only adjust the rate of clk.
1837 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1838 * propagate up to clk's parent; whether or not this happens depends on the
1839 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1840 * after calling .round_rate then upstream parent propagation is ignored. If
1841 * *parent_rate comes back with a new rate for clk's parent then we propagate
1842 * up to clk's parent and set its rate. Upward propagation will continue
1843 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1844 * .round_rate stops requesting changes to clk's parent_rate.
1846 * Rate changes are accomplished via tree traversal that also recalculates the
1847 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1849 * Returns 0 on success, -EERROR otherwise.
1851 int clk_set_rate(struct clk *clk, unsigned long rate)
1858 /* prevent racing with updates to the clock topology */
1861 ret = clk_core_set_rate_nolock(clk->core, rate);
1863 clk_prepare_unlock();
1867 EXPORT_SYMBOL_GPL(clk_set_rate);
1870 * clk_set_rate_range - set a rate range for a clock source
1871 * @clk: clock source
1872 * @min: desired minimum clock rate in Hz, inclusive
1873 * @max: desired maximum clock rate in Hz, inclusive
1875 * Returns success (0) or negative errno.
1877 int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
1885 pr_err("%s: clk %s dev %s con %s: invalid range [%lu, %lu]\n",
1886 __func__, clk->core->name, clk->dev_id, clk->con_id,
1893 if (min != clk->min_rate || max != clk->max_rate) {
1894 clk->min_rate = min;
1895 clk->max_rate = max;
1896 ret = clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
1899 clk_prepare_unlock();
1903 EXPORT_SYMBOL_GPL(clk_set_rate_range);
1906 * clk_set_min_rate - set a minimum clock rate for a clock source
1907 * @clk: clock source
1908 * @rate: desired minimum clock rate in Hz, inclusive
1910 * Returns success (0) or negative errno.
1912 int clk_set_min_rate(struct clk *clk, unsigned long rate)
1917 return clk_set_rate_range(clk, rate, clk->max_rate);
1919 EXPORT_SYMBOL_GPL(clk_set_min_rate);
1922 * clk_set_max_rate - set a maximum clock rate for a clock source
1923 * @clk: clock source
1924 * @rate: desired maximum clock rate in Hz, inclusive
1926 * Returns success (0) or negative errno.
1928 int clk_set_max_rate(struct clk *clk, unsigned long rate)
1933 return clk_set_rate_range(clk, clk->min_rate, rate);
1935 EXPORT_SYMBOL_GPL(clk_set_max_rate);
1938 * clk_get_parent - return the parent of a clk
1939 * @clk: the clk whose parent gets returned
1941 * Simply returns clk->parent. Returns NULL if clk is NULL.
1943 struct clk *clk_get_parent(struct clk *clk)
1948 parent = __clk_get_parent(clk);
1949 clk_prepare_unlock();
1953 EXPORT_SYMBOL_GPL(clk_get_parent);
1956 * .get_parent is mandatory for clocks with multiple possible parents. It is
1957 * optional for single-parent clocks. Always call .get_parent if it is
1958 * available and WARN if it is missing for multi-parent clocks.
1960 * For single-parent clocks without .get_parent, first check to see if the
1961 * .parents array exists, and if so use it to avoid an expensive tree
1962 * traversal. If .parents does not exist then walk the tree.
1964 static struct clk_core *__clk_init_parent(struct clk_core *clk)
1966 struct clk_core *ret = NULL;
1969 /* handle the trivial cases */
1971 if (!clk->num_parents)
1974 if (clk->num_parents == 1) {
1975 if (IS_ERR_OR_NULL(clk->parent))
1976 clk->parent = clk_core_lookup(clk->parent_names[0]);
1981 if (!clk->ops->get_parent) {
1982 WARN(!clk->ops->get_parent,
1983 "%s: multi-parent clocks must implement .get_parent\n",
1989 * Do our best to cache parent clocks in clk->parents. This prevents
1990 * unnecessary and expensive lookups. We don't set clk->parent here;
1991 * that is done by the calling function.
1994 index = clk->ops->get_parent(clk->hw);
1998 kcalloc(clk->num_parents, sizeof(struct clk *),
2001 ret = clk_core_get_parent_by_index(clk, index);
2007 static void clk_core_reparent(struct clk_core *clk,
2008 struct clk_core *new_parent)
2010 clk_reparent(clk, new_parent);
2011 __clk_recalc_accuracies(clk);
2012 __clk_recalc_rates(clk, POST_RATE_CHANGE);
2016 * clk_has_parent - check if a clock is a possible parent for another
2017 * @clk: clock source
2018 * @parent: parent clock source
2020 * This function can be used in drivers that need to check that a clock can be
2021 * the parent of another without actually changing the parent.
2023 * Returns true if @parent is a possible parent for @clk, false otherwise.
2025 bool clk_has_parent(struct clk *clk, struct clk *parent)
2027 struct clk_core *core, *parent_core;
2030 /* NULL clocks should be nops, so return success if either is NULL. */
2031 if (!clk || !parent)
2035 parent_core = parent->core;
2037 /* Optimize for the case where the parent is already the parent. */
2038 if (core->parent == parent_core)
2041 for (i = 0; i < core->num_parents; i++)
2042 if (strcmp(core->parent_names[i], parent_core->name) == 0)
2047 EXPORT_SYMBOL_GPL(clk_has_parent);
2049 static int clk_core_set_parent(struct clk_core *clk, struct clk_core *parent)
2053 unsigned long p_rate = 0;
2058 /* prevent racing with updates to the clock topology */
2061 if (clk->parent == parent)
2064 /* verify ops for for multi-parent clks */
2065 if ((clk->num_parents > 1) && (!clk->ops->set_parent)) {
2070 /* check that we are allowed to re-parent if the clock is in use */
2071 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
2076 /* try finding the new parent index */
2078 p_index = clk_fetch_parent_index(clk, parent);
2079 p_rate = parent->rate;
2081 pr_debug("%s: clk %s can not be parent of clk %s\n",
2082 __func__, parent->name, clk->name);
2088 /* propagate PRE_RATE_CHANGE notifications */
2089 ret = __clk_speculate_rates(clk, p_rate);
2091 /* abort if a driver objects */
2092 if (ret & NOTIFY_STOP_MASK)
2095 /* do the re-parent */
2096 ret = __clk_set_parent(clk, parent, p_index);
2098 /* propagate rate an accuracy recalculation accordingly */
2100 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
2102 __clk_recalc_rates(clk, POST_RATE_CHANGE);
2103 __clk_recalc_accuracies(clk);
2107 clk_prepare_unlock();
2113 * clk_set_parent - switch the parent of a mux clk
2114 * @clk: the mux clk whose input we are switching
2115 * @parent: the new input to clk
2117 * Re-parent clk to use parent as its new input source. If clk is in
2118 * prepared state, the clk will get enabled for the duration of this call. If
2119 * that's not acceptable for a specific clk (Eg: the consumer can't handle
2120 * that, the reparenting is glitchy in hardware, etc), use the
2121 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
2123 * After successfully changing clk's parent clk_set_parent will update the
2124 * clk topology, sysfs topology and propagate rate recalculation via
2125 * __clk_recalc_rates.
2127 * Returns 0 on success, -EERROR otherwise.
2129 int clk_set_parent(struct clk *clk, struct clk *parent)
2134 return clk_core_set_parent(clk->core, parent ? parent->core : NULL);
2136 EXPORT_SYMBOL_GPL(clk_set_parent);
2139 * clk_set_phase - adjust the phase shift of a clock signal
2140 * @clk: clock signal source
2141 * @degrees: number of degrees the signal is shifted
2143 * Shifts the phase of a clock signal by the specified
2144 * degrees. Returns 0 on success, -EERROR otherwise.
2146 * This function makes no distinction about the input or reference
2147 * signal that we adjust the clock signal phase against. For example
2148 * phase locked-loop clock signal generators we may shift phase with
2149 * respect to feedback clock signal input, but for other cases the
2150 * clock phase may be shifted with respect to some other, unspecified
2153 * Additionally the concept of phase shift does not propagate through
2154 * the clock tree hierarchy, which sets it apart from clock rates and
2155 * clock accuracy. A parent clock phase attribute does not have an
2156 * impact on the phase attribute of a child clock.
2158 int clk_set_phase(struct clk *clk, int degrees)
2165 /* sanity check degrees */
2172 trace_clk_set_phase(clk->core, degrees);
2174 if (clk->core->ops->set_phase)
2175 ret = clk->core->ops->set_phase(clk->core->hw, degrees);
2177 trace_clk_set_phase_complete(clk->core, degrees);
2180 clk->core->phase = degrees;
2182 clk_prepare_unlock();
2186 EXPORT_SYMBOL_GPL(clk_set_phase);
2188 static int clk_core_get_phase(struct clk_core *clk)
2197 clk_prepare_unlock();
2202 EXPORT_SYMBOL_GPL(clk_get_phase);
2205 * clk_get_phase - return the phase shift of a clock signal
2206 * @clk: clock signal source
2208 * Returns the phase shift of a clock node in degrees, otherwise returns
2211 int clk_get_phase(struct clk *clk)
2216 return clk_core_get_phase(clk->core);
2220 * __clk_init - initialize the data structures in a struct clk
2221 * @dev: device initializing this clk, placeholder for now
2222 * @clk: clk being initialized
2224 * Initializes the lists in struct clk_core, queries the hardware for the
2225 * parent and rate and sets them both.
2227 static int __clk_init(struct device *dev, struct clk *clk_user)
2230 struct clk_core *orphan;
2231 struct hlist_node *tmp2;
2232 struct clk_core *clk;
2238 clk = clk_user->core;
2242 /* check to see if a clock with this name is already registered */
2243 if (clk_core_lookup(clk->name)) {
2244 pr_debug("%s: clk %s already initialized\n",
2245 __func__, clk->name);
2250 /* check that clk_ops are sane. See Documentation/clk.txt */
2251 if (clk->ops->set_rate &&
2252 !((clk->ops->round_rate || clk->ops->determine_rate) &&
2253 clk->ops->recalc_rate)) {
2254 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
2255 __func__, clk->name);
2260 if (clk->ops->set_parent && !clk->ops->get_parent) {
2261 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
2262 __func__, clk->name);
2267 if (clk->ops->set_rate_and_parent &&
2268 !(clk->ops->set_parent && clk->ops->set_rate)) {
2269 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
2270 __func__, clk->name);
2275 /* throw a WARN if any entries in parent_names are NULL */
2276 for (i = 0; i < clk->num_parents; i++)
2277 WARN(!clk->parent_names[i],
2278 "%s: invalid NULL in %s's .parent_names\n",
2279 __func__, clk->name);
2282 * Allocate an array of struct clk *'s to avoid unnecessary string
2283 * look-ups of clk's possible parents. This can fail for clocks passed
2284 * in to clk_init during early boot; thus any access to clk->parents[]
2285 * must always check for a NULL pointer and try to populate it if
2288 * If clk->parents is not NULL we skip this entire block. This allows
2289 * for clock drivers to statically initialize clk->parents.
2291 if (clk->num_parents > 1 && !clk->parents) {
2292 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
2295 * clk_core_lookup returns NULL for parents that have not been
2296 * clk_init'd; thus any access to clk->parents[] must check
2297 * for a NULL pointer. We can always perform lazy lookups for
2298 * missing parents later on.
2301 for (i = 0; i < clk->num_parents; i++)
2303 clk_core_lookup(clk->parent_names[i]);
2306 clk->parent = __clk_init_parent(clk);
2309 * Populate clk->parent if parent has already been __clk_init'd. If
2310 * parent has not yet been __clk_init'd then place clk in the orphan
2311 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
2314 * Every time a new clk is clk_init'd then we walk the list of orphan
2315 * clocks and re-parent any that are children of the clock currently
2319 hlist_add_head(&clk->child_node,
2320 &clk->parent->children);
2321 else if (clk->flags & CLK_IS_ROOT)
2322 hlist_add_head(&clk->child_node, &clk_root_list);
2324 hlist_add_head(&clk->child_node, &clk_orphan_list);
2327 * Set clk's accuracy. The preferred method is to use
2328 * .recalc_accuracy. For simple clocks and lazy developers the default
2329 * fallback is to use the parent's accuracy. If a clock doesn't have a
2330 * parent (or is orphaned) then accuracy is set to zero (perfect
2333 if (clk->ops->recalc_accuracy)
2334 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
2335 __clk_get_accuracy(clk->parent));
2336 else if (clk->parent)
2337 clk->accuracy = clk->parent->accuracy;
2343 * Since a phase is by definition relative to its parent, just
2344 * query the current clock phase, or just assume it's in phase.
2346 if (clk->ops->get_phase)
2347 clk->phase = clk->ops->get_phase(clk->hw);
2352 * Set clk's rate. The preferred method is to use .recalc_rate. For
2353 * simple clocks and lazy developers the default fallback is to use the
2354 * parent's rate. If a clock doesn't have a parent (or is orphaned)
2355 * then rate is set to zero.
2357 if (clk->ops->recalc_rate)
2358 rate = clk->ops->recalc_rate(clk->hw,
2359 clk_core_get_rate_nolock(clk->parent));
2360 else if (clk->parent)
2361 rate = clk->parent->rate;
2364 clk->rate = clk->req_rate = rate;
2367 * walk the list of orphan clocks and reparent any that are children of
2370 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
2371 if (orphan->num_parents && orphan->ops->get_parent) {
2372 i = orphan->ops->get_parent(orphan->hw);
2373 if (!strcmp(clk->name, orphan->parent_names[i]))
2374 clk_core_reparent(orphan, clk);
2378 for (i = 0; i < orphan->num_parents; i++)
2379 if (!strcmp(clk->name, orphan->parent_names[i])) {
2380 clk_core_reparent(orphan, clk);
2386 * optional platform-specific magic
2388 * The .init callback is not used by any of the basic clock types, but
2389 * exists for weird hardware that must perform initialization magic.
2390 * Please consider other ways of solving initialization problems before
2391 * using this callback, as its use is discouraged.
2394 clk->ops->init(clk->hw);
2396 kref_init(&clk->ref);
2398 clk_prepare_unlock();
2401 clk_debug_register(clk);
2406 struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
2411 /* This is to allow this function to be chained to others */
2412 if (!hw || IS_ERR(hw))
2413 return (struct clk *) hw;
2415 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2417 return ERR_PTR(-ENOMEM);
2419 clk->core = hw->core;
2420 clk->dev_id = dev_id;
2421 clk->con_id = con_id;
2422 clk->max_rate = ULONG_MAX;
2425 hlist_add_head(&clk->child_node, &hw->core->clks);
2426 clk_prepare_unlock();
2431 void __clk_free_clk(struct clk *clk)
2434 hlist_del(&clk->child_node);
2435 clk_prepare_unlock();
2441 * clk_register - allocate a new clock, register it and return an opaque cookie
2442 * @dev: device that is registering this clock
2443 * @hw: link to hardware-specific clock data
2445 * clk_register is the primary interface for populating the clock tree with new
2446 * clock nodes. It returns a pointer to the newly allocated struct clk which
2447 * cannot be dereferenced by driver code but may be used in conjuction with the
2448 * rest of the clock API. In the event of an error clk_register will return an
2449 * error code; drivers must test for an error code after calling clk_register.
2451 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
2454 struct clk_core *clk;
2456 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2458 pr_err("%s: could not allocate clk\n", __func__);
2463 clk->name = kstrdup_const(hw->init->name, GFP_KERNEL);
2465 pr_err("%s: could not allocate clk->name\n", __func__);
2469 clk->ops = hw->init->ops;
2470 if (dev && dev->driver)
2471 clk->owner = dev->driver->owner;
2473 clk->flags = hw->init->flags;
2474 clk->num_parents = hw->init->num_parents;
2477 /* allocate local copy in case parent_names is __initdata */
2478 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
2481 if (!clk->parent_names) {
2482 pr_err("%s: could not allocate clk->parent_names\n", __func__);
2484 goto fail_parent_names;
2488 /* copy each string name in case parent_names is __initdata */
2489 for (i = 0; i < clk->num_parents; i++) {
2490 clk->parent_names[i] = kstrdup_const(hw->init->parent_names[i],
2492 if (!clk->parent_names[i]) {
2493 pr_err("%s: could not copy parent_names\n", __func__);
2495 goto fail_parent_names_copy;
2499 INIT_HLIST_HEAD(&clk->clks);
2501 hw->clk = __clk_create_clk(hw, NULL, NULL);
2502 if (IS_ERR(hw->clk)) {
2503 pr_err("%s: could not allocate per-user clk\n", __func__);
2504 ret = PTR_ERR(hw->clk);
2505 goto fail_parent_names_copy;
2508 ret = __clk_init(dev, hw->clk);
2512 __clk_free_clk(hw->clk);
2515 fail_parent_names_copy:
2517 kfree_const(clk->parent_names[i]);
2518 kfree(clk->parent_names);
2520 kfree_const(clk->name);
2524 return ERR_PTR(ret);
2526 EXPORT_SYMBOL_GPL(clk_register);
2529 * Free memory allocated for a clock.
2530 * Caller must hold prepare_lock.
2532 static void __clk_release(struct kref *ref)
2534 struct clk_core *clk = container_of(ref, struct clk_core, ref);
2535 int i = clk->num_parents;
2537 lockdep_assert_held(&prepare_lock);
2539 kfree(clk->parents);
2541 kfree_const(clk->parent_names[i]);
2543 kfree(clk->parent_names);
2544 kfree_const(clk->name);
2549 * Empty clk_ops for unregistered clocks. These are used temporarily
2550 * after clk_unregister() was called on a clock and until last clock
2551 * consumer calls clk_put() and the struct clk object is freed.
2553 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2558 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2563 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2564 unsigned long parent_rate)
2569 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2574 static const struct clk_ops clk_nodrv_ops = {
2575 .enable = clk_nodrv_prepare_enable,
2576 .disable = clk_nodrv_disable_unprepare,
2577 .prepare = clk_nodrv_prepare_enable,
2578 .unprepare = clk_nodrv_disable_unprepare,
2579 .set_rate = clk_nodrv_set_rate,
2580 .set_parent = clk_nodrv_set_parent,
2584 * clk_unregister - unregister a currently registered clock
2585 * @clk: clock to unregister
2587 void clk_unregister(struct clk *clk)
2589 unsigned long flags;
2591 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2594 clk_debug_unregister(clk->core);
2598 if (clk->core->ops == &clk_nodrv_ops) {
2599 pr_err("%s: unregistered clock: %s\n", __func__,
2604 * Assign empty clock ops for consumers that might still hold
2605 * a reference to this clock.
2607 flags = clk_enable_lock();
2608 clk->core->ops = &clk_nodrv_ops;
2609 clk_enable_unlock(flags);
2611 if (!hlist_empty(&clk->core->children)) {
2612 struct clk_core *child;
2613 struct hlist_node *t;
2615 /* Reparent all children to the orphan list. */
2616 hlist_for_each_entry_safe(child, t, &clk->core->children,
2618 clk_core_set_parent(child, NULL);
2621 hlist_del_init(&clk->core->child_node);
2623 if (clk->core->prepare_count)
2624 pr_warn("%s: unregistering prepared clock: %s\n",
2625 __func__, clk->core->name);
2626 kref_put(&clk->core->ref, __clk_release);
2628 clk_prepare_unlock();
2630 EXPORT_SYMBOL_GPL(clk_unregister);
2632 static void devm_clk_release(struct device *dev, void *res)
2634 clk_unregister(*(struct clk **)res);
2638 * devm_clk_register - resource managed clk_register()
2639 * @dev: device that is registering this clock
2640 * @hw: link to hardware-specific clock data
2642 * Managed clk_register(). Clocks returned from this function are
2643 * automatically clk_unregister()ed on driver detach. See clk_register() for
2646 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2651 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2653 return ERR_PTR(-ENOMEM);
2655 clk = clk_register(dev, hw);
2658 devres_add(dev, clkp);
2665 EXPORT_SYMBOL_GPL(devm_clk_register);
2667 static int devm_clk_match(struct device *dev, void *res, void *data)
2669 struct clk *c = res;
2676 * devm_clk_unregister - resource managed clk_unregister()
2677 * @clk: clock to unregister
2679 * Deallocate a clock allocated with devm_clk_register(). Normally
2680 * this function will not need to be called and the resource management
2681 * code will ensure that the resource is freed.
2683 void devm_clk_unregister(struct device *dev, struct clk *clk)
2685 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2687 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2692 int __clk_get(struct clk *clk)
2694 struct clk_core *core = !clk ? NULL : clk->core;
2697 if (!try_module_get(core->owner))
2700 kref_get(&core->ref);
2705 void __clk_put(struct clk *clk)
2707 struct module *owner;
2709 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2714 hlist_del(&clk->child_node);
2715 if (clk->min_rate > clk->core->req_rate ||
2716 clk->max_rate < clk->core->req_rate)
2717 clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
2719 owner = clk->core->owner;
2720 kref_put(&clk->core->ref, __clk_release);
2722 clk_prepare_unlock();
2729 /*** clk rate change notifiers ***/
2732 * clk_notifier_register - add a clk rate change notifier
2733 * @clk: struct clk * to watch
2734 * @nb: struct notifier_block * with callback info
2736 * Request notification when clk's rate changes. This uses an SRCU
2737 * notifier because we want it to block and notifier unregistrations are
2738 * uncommon. The callbacks associated with the notifier must not
2739 * re-enter into the clk framework by calling any top-level clk APIs;
2740 * this will cause a nested prepare_lock mutex.
2742 * In all notification cases cases (pre, post and abort rate change) the
2743 * original clock rate is passed to the callback via struct
2744 * clk_notifier_data.old_rate and the new frequency is passed via struct
2745 * clk_notifier_data.new_rate.
2747 * clk_notifier_register() must be called from non-atomic context.
2748 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2749 * allocation failure; otherwise, passes along the return value of
2750 * srcu_notifier_chain_register().
2752 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2754 struct clk_notifier *cn;
2762 /* search the list of notifiers for this clk */
2763 list_for_each_entry(cn, &clk_notifier_list, node)
2767 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2768 if (cn->clk != clk) {
2769 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2774 srcu_init_notifier_head(&cn->notifier_head);
2776 list_add(&cn->node, &clk_notifier_list);
2779 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2781 clk->core->notifier_count++;
2784 clk_prepare_unlock();
2788 EXPORT_SYMBOL_GPL(clk_notifier_register);
2791 * clk_notifier_unregister - remove a clk rate change notifier
2792 * @clk: struct clk *
2793 * @nb: struct notifier_block * with callback info
2795 * Request no further notification for changes to 'clk' and frees memory
2796 * allocated in clk_notifier_register.
2798 * Returns -EINVAL if called with null arguments; otherwise, passes
2799 * along the return value of srcu_notifier_chain_unregister().
2801 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2803 struct clk_notifier *cn = NULL;
2811 list_for_each_entry(cn, &clk_notifier_list, node)
2815 if (cn->clk == clk) {
2816 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2818 clk->core->notifier_count--;
2820 /* XXX the notifier code should handle this better */
2821 if (!cn->notifier_head.head) {
2822 srcu_cleanup_notifier_head(&cn->notifier_head);
2823 list_del(&cn->node);
2831 clk_prepare_unlock();
2835 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2839 * struct of_clk_provider - Clock provider registration structure
2840 * @link: Entry in global list of clock providers
2841 * @node: Pointer to device tree node of clock provider
2842 * @get: Get clock callback. Returns NULL or a struct clk for the
2843 * given clock specifier
2844 * @data: context pointer to be passed into @get callback
2846 struct of_clk_provider {
2847 struct list_head link;
2849 struct device_node *node;
2850 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2854 static const struct of_device_id __clk_of_table_sentinel
2855 __used __section(__clk_of_table_end);
2857 static LIST_HEAD(of_clk_providers);
2858 static DEFINE_MUTEX(of_clk_mutex);
2860 /* of_clk_provider list locking helpers */
2861 void of_clk_lock(void)
2863 mutex_lock(&of_clk_mutex);
2866 void of_clk_unlock(void)
2868 mutex_unlock(&of_clk_mutex);
2871 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2876 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2878 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2880 struct clk_onecell_data *clk_data = data;
2881 unsigned int idx = clkspec->args[0];
2883 if (idx >= clk_data->clk_num) {
2884 pr_err("%s: invalid clock index %d\n", __func__, idx);
2885 return ERR_PTR(-EINVAL);
2888 return clk_data->clks[idx];
2890 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2893 * of_clk_add_provider() - Register a clock provider for a node
2894 * @np: Device node pointer associated with clock provider
2895 * @clk_src_get: callback for decoding clock
2896 * @data: context pointer for @clk_src_get callback.
2898 int of_clk_add_provider(struct device_node *np,
2899 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2903 struct of_clk_provider *cp;
2906 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2910 cp->node = of_node_get(np);
2912 cp->get = clk_src_get;
2914 mutex_lock(&of_clk_mutex);
2915 list_add(&cp->link, &of_clk_providers);
2916 mutex_unlock(&of_clk_mutex);
2917 pr_debug("Added clock from %s\n", np->full_name);
2919 ret = of_clk_set_defaults(np, true);
2921 of_clk_del_provider(np);
2925 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2928 * of_clk_del_provider() - Remove a previously registered clock provider
2929 * @np: Device node pointer associated with clock provider
2931 void of_clk_del_provider(struct device_node *np)
2933 struct of_clk_provider *cp;
2935 mutex_lock(&of_clk_mutex);
2936 list_for_each_entry(cp, &of_clk_providers, link) {
2937 if (cp->node == np) {
2938 list_del(&cp->link);
2939 of_node_put(cp->node);
2944 mutex_unlock(&of_clk_mutex);
2946 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2948 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
2949 const char *dev_id, const char *con_id)
2951 struct of_clk_provider *provider;
2952 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2954 /* Check if we have such a provider in our array */
2955 list_for_each_entry(provider, &of_clk_providers, link) {
2956 if (provider->node == clkspec->np)
2957 clk = provider->get(clkspec, provider->data);
2959 clk = __clk_create_clk(__clk_get_hw(clk), dev_id,
2962 if (!IS_ERR(clk) && !__clk_get(clk)) {
2963 __clk_free_clk(clk);
2964 clk = ERR_PTR(-ENOENT);
2974 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2978 mutex_lock(&of_clk_mutex);
2979 clk = __of_clk_get_from_provider(clkspec, NULL, __func__);
2980 mutex_unlock(&of_clk_mutex);
2985 int of_clk_get_parent_count(struct device_node *np)
2987 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2989 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2991 const char *of_clk_get_parent_name(struct device_node *np, int index)
2993 struct of_phandle_args clkspec;
2994 struct property *prop;
2995 const char *clk_name;
3004 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
3009 index = clkspec.args_count ? clkspec.args[0] : 0;
3012 /* if there is an indices property, use it to transfer the index
3013 * specified into an array offset for the clock-output-names property.
3015 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
3023 if (of_property_read_string_index(clkspec.np, "clock-output-names",
3026 clk_name = clkspec.np->name;
3028 of_node_put(clkspec.np);
3031 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
3033 struct clock_provider {
3034 of_clk_init_cb_t clk_init_cb;
3035 struct device_node *np;
3036 struct list_head node;
3039 static LIST_HEAD(clk_provider_list);
3042 * This function looks for a parent clock. If there is one, then it
3043 * checks that the provider for this parent clock was initialized, in
3044 * this case the parent clock will be ready.
3046 static int parent_ready(struct device_node *np)
3051 struct clk *clk = of_clk_get(np, i);
3053 /* this parent is ready we can check the next one */
3060 /* at least one parent is not ready, we exit now */
3061 if (PTR_ERR(clk) == -EPROBE_DEFER)
3065 * Here we make assumption that the device tree is
3066 * written correctly. So an error means that there is
3067 * no more parent. As we didn't exit yet, then the
3068 * previous parent are ready. If there is no clock
3069 * parent, no need to wait for them, then we can
3070 * consider their absence as being ready
3077 * of_clk_init() - Scan and init clock providers from the DT
3078 * @matches: array of compatible values and init functions for providers.
3080 * This function scans the device tree for matching clock providers
3081 * and calls their initialization functions. It also does it by trying
3082 * to follow the dependencies.
3084 void __init of_clk_init(const struct of_device_id *matches)
3086 const struct of_device_id *match;
3087 struct device_node *np;
3088 struct clock_provider *clk_provider, *next;
3093 matches = &__clk_of_table;
3095 /* First prepare the list of the clocks providers */
3096 for_each_matching_node_and_match(np, matches, &match) {
3097 struct clock_provider *parent =
3098 kzalloc(sizeof(struct clock_provider), GFP_KERNEL);
3100 parent->clk_init_cb = match->data;
3102 list_add_tail(&parent->node, &clk_provider_list);
3105 while (!list_empty(&clk_provider_list)) {
3106 is_init_done = false;
3107 list_for_each_entry_safe(clk_provider, next,
3108 &clk_provider_list, node) {
3109 if (force || parent_ready(clk_provider->np)) {
3111 clk_provider->clk_init_cb(clk_provider->np);
3112 of_clk_set_defaults(clk_provider->np, true);
3114 list_del(&clk_provider->node);
3115 kfree(clk_provider);
3116 is_init_done = true;
3121 * We didn't manage to initialize any of the
3122 * remaining providers during the last loop, so now we
3123 * initialize all the remaining ones unconditionally
3124 * in case the clock parent was not mandatory