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;
81 struct clk_core *core;
84 unsigned long min_rate;
85 unsigned long max_rate;
86 struct hlist_node child_node;
90 static void clk_prepare_lock(void)
92 if (!mutex_trylock(&prepare_lock)) {
93 if (prepare_owner == current) {
97 mutex_lock(&prepare_lock);
99 WARN_ON_ONCE(prepare_owner != NULL);
100 WARN_ON_ONCE(prepare_refcnt != 0);
101 prepare_owner = current;
105 static void clk_prepare_unlock(void)
107 WARN_ON_ONCE(prepare_owner != current);
108 WARN_ON_ONCE(prepare_refcnt == 0);
110 if (--prepare_refcnt)
112 prepare_owner = NULL;
113 mutex_unlock(&prepare_lock);
116 static unsigned long clk_enable_lock(void)
120 if (!spin_trylock_irqsave(&enable_lock, flags)) {
121 if (enable_owner == current) {
125 spin_lock_irqsave(&enable_lock, flags);
127 WARN_ON_ONCE(enable_owner != NULL);
128 WARN_ON_ONCE(enable_refcnt != 0);
129 enable_owner = current;
134 static void clk_enable_unlock(unsigned long flags)
136 WARN_ON_ONCE(enable_owner != current);
137 WARN_ON_ONCE(enable_refcnt == 0);
142 spin_unlock_irqrestore(&enable_lock, flags);
145 /*** debugfs support ***/
147 #ifdef CONFIG_DEBUG_FS
148 #include <linux/debugfs.h>
150 static struct dentry *rootdir;
151 static int inited = 0;
152 static DEFINE_MUTEX(clk_debug_lock);
153 static HLIST_HEAD(clk_debug_list);
155 static struct hlist_head *all_lists[] = {
161 static struct hlist_head *orphan_list[] = {
166 static void clk_summary_show_one(struct seq_file *s, struct clk_core *c,
172 seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
174 30 - level * 3, c->name,
175 c->enable_count, c->prepare_count, clk_core_get_rate(c),
176 clk_core_get_accuracy(c), clk_core_get_phase(c));
179 static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c,
182 struct clk_core *child;
187 clk_summary_show_one(s, c, level);
189 hlist_for_each_entry(child, &c->children, child_node)
190 clk_summary_show_subtree(s, child, level + 1);
193 static int clk_summary_show(struct seq_file *s, void *data)
196 struct hlist_head **lists = (struct hlist_head **)s->private;
198 seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy phase\n");
199 seq_puts(s, "----------------------------------------------------------------------------------------\n");
203 for (; *lists; lists++)
204 hlist_for_each_entry(c, *lists, child_node)
205 clk_summary_show_subtree(s, c, 0);
207 clk_prepare_unlock();
213 static int clk_summary_open(struct inode *inode, struct file *file)
215 return single_open(file, clk_summary_show, inode->i_private);
218 static const struct file_operations clk_summary_fops = {
219 .open = clk_summary_open,
222 .release = single_release,
225 static void clk_dump_one(struct seq_file *s, struct clk_core *c, int level)
230 seq_printf(s, "\"%s\": { ", c->name);
231 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
232 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
233 seq_printf(s, "\"rate\": %lu", clk_core_get_rate(c));
234 seq_printf(s, "\"accuracy\": %lu", clk_core_get_accuracy(c));
235 seq_printf(s, "\"phase\": %d", clk_core_get_phase(c));
238 static void clk_dump_subtree(struct seq_file *s, struct clk_core *c, int level)
240 struct clk_core *child;
245 clk_dump_one(s, c, level);
247 hlist_for_each_entry(child, &c->children, child_node) {
249 clk_dump_subtree(s, child, level + 1);
255 static int clk_dump(struct seq_file *s, void *data)
258 bool first_node = true;
259 struct hlist_head **lists = (struct hlist_head **)s->private;
265 for (; *lists; lists++) {
266 hlist_for_each_entry(c, *lists, child_node) {
270 clk_dump_subtree(s, c, 0);
274 clk_prepare_unlock();
281 static int clk_dump_open(struct inode *inode, struct file *file)
283 return single_open(file, clk_dump, inode->i_private);
286 static const struct file_operations clk_dump_fops = {
287 .open = clk_dump_open,
290 .release = single_release,
293 static int clk_debug_create_one(struct clk_core *clk, struct dentry *pdentry)
298 if (!clk || !pdentry) {
303 d = debugfs_create_dir(clk->name, pdentry);
309 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
314 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
315 (u32 *)&clk->accuracy);
319 d = debugfs_create_u32("clk_phase", S_IRUGO, clk->dentry,
324 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
329 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
330 (u32 *)&clk->prepare_count);
334 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
335 (u32 *)&clk->enable_count);
339 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
340 (u32 *)&clk->notifier_count);
344 if (clk->ops->debug_init) {
345 ret = clk->ops->debug_init(clk->hw, clk->dentry);
354 debugfs_remove_recursive(clk->dentry);
361 * clk_debug_register - add a clk node to the debugfs clk tree
362 * @clk: the clk being added to the debugfs clk tree
364 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
365 * initialized. Otherwise it bails out early since the debugfs clk tree
366 * will be created lazily by clk_debug_init as part of a late_initcall.
368 static int clk_debug_register(struct clk_core *clk)
372 mutex_lock(&clk_debug_lock);
373 hlist_add_head(&clk->debug_node, &clk_debug_list);
378 ret = clk_debug_create_one(clk, rootdir);
380 mutex_unlock(&clk_debug_lock);
386 * clk_debug_unregister - remove a clk node from the debugfs clk tree
387 * @clk: the clk being removed from the debugfs clk tree
389 * Dynamically removes a clk and all it's children clk nodes from the
390 * debugfs clk tree if clk->dentry points to debugfs created by
391 * clk_debug_register in __clk_init.
393 static void clk_debug_unregister(struct clk_core *clk)
395 mutex_lock(&clk_debug_lock);
396 hlist_del_init(&clk->debug_node);
397 debugfs_remove_recursive(clk->dentry);
399 mutex_unlock(&clk_debug_lock);
402 struct dentry *clk_debugfs_add_file(struct clk_hw *hw, char *name, umode_t mode,
403 void *data, const struct file_operations *fops)
405 struct dentry *d = NULL;
407 if (hw->core->dentry)
408 d = debugfs_create_file(name, mode, hw->core->dentry, data,
413 EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
416 * clk_debug_init - lazily create the debugfs clk tree visualization
418 * clks are often initialized very early during boot before memory can
419 * be dynamically allocated and well before debugfs is setup.
420 * clk_debug_init walks the clk tree hierarchy while holding
421 * prepare_lock and creates the topology as part of a late_initcall,
422 * thus insuring that clks initialized very early will still be
423 * represented in the debugfs clk tree. This function should only be
424 * called once at boot-time, and all other clks added dynamically will
425 * be done so with clk_debug_register.
427 static int __init clk_debug_init(void)
429 struct clk_core *clk;
432 rootdir = debugfs_create_dir("clk", NULL);
437 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists,
442 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists,
447 d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir,
448 &orphan_list, &clk_summary_fops);
452 d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir,
453 &orphan_list, &clk_dump_fops);
457 mutex_lock(&clk_debug_lock);
458 hlist_for_each_entry(clk, &clk_debug_list, debug_node)
459 clk_debug_create_one(clk, rootdir);
462 mutex_unlock(&clk_debug_lock);
466 late_initcall(clk_debug_init);
468 static inline int clk_debug_register(struct clk_core *clk) { return 0; }
469 static inline void clk_debug_reparent(struct clk_core *clk,
470 struct clk_core *new_parent)
473 static inline void clk_debug_unregister(struct clk_core *clk)
478 /* caller must hold prepare_lock */
479 static void clk_unprepare_unused_subtree(struct clk_core *clk)
481 struct clk_core *child;
483 hlist_for_each_entry(child, &clk->children, child_node)
484 clk_unprepare_unused_subtree(child);
486 if (clk->prepare_count)
489 if (clk->flags & CLK_IGNORE_UNUSED)
492 if (clk_core_is_prepared(clk)) {
493 if (clk->ops->unprepare_unused)
494 clk->ops->unprepare_unused(clk->hw);
495 else if (clk->ops->unprepare)
496 clk->ops->unprepare(clk->hw);
500 /* caller must hold prepare_lock */
501 static void clk_disable_unused_subtree(struct clk_core *clk)
503 struct clk_core *child;
506 hlist_for_each_entry(child, &clk->children, child_node)
507 clk_disable_unused_subtree(child);
509 flags = clk_enable_lock();
511 if (clk->enable_count)
514 if (clk->flags & CLK_IGNORE_UNUSED)
518 * some gate clocks have special needs during the disable-unused
519 * sequence. call .disable_unused if available, otherwise fall
522 if (clk_core_is_enabled(clk)) {
523 if (clk->ops->disable_unused)
524 clk->ops->disable_unused(clk->hw);
525 else if (clk->ops->disable)
526 clk->ops->disable(clk->hw);
530 clk_enable_unlock(flags);
533 static bool clk_ignore_unused;
534 static int __init clk_ignore_unused_setup(char *__unused)
536 clk_ignore_unused = true;
539 __setup("clk_ignore_unused", clk_ignore_unused_setup);
541 static int clk_disable_unused(void)
543 struct clk_core *clk;
545 if (clk_ignore_unused) {
546 pr_warn("clk: Not disabling unused clocks\n");
552 hlist_for_each_entry(clk, &clk_root_list, child_node)
553 clk_disable_unused_subtree(clk);
555 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
556 clk_disable_unused_subtree(clk);
558 hlist_for_each_entry(clk, &clk_root_list, child_node)
559 clk_unprepare_unused_subtree(clk);
561 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
562 clk_unprepare_unused_subtree(clk);
564 clk_prepare_unlock();
568 late_initcall_sync(clk_disable_unused);
570 /*** helper functions ***/
572 const char *__clk_get_name(struct clk *clk)
574 return !clk ? NULL : clk->core->name;
576 EXPORT_SYMBOL_GPL(__clk_get_name);
578 struct clk_hw *__clk_get_hw(struct clk *clk)
580 return !clk ? NULL : clk->core->hw;
582 EXPORT_SYMBOL_GPL(__clk_get_hw);
584 u8 __clk_get_num_parents(struct clk *clk)
586 return !clk ? 0 : clk->core->num_parents;
588 EXPORT_SYMBOL_GPL(__clk_get_num_parents);
590 struct clk *__clk_get_parent(struct clk *clk)
595 /* TODO: Create a per-user clk and change callers to call clk_put */
596 return !clk->core->parent ? NULL : clk->core->parent->hw->clk;
598 EXPORT_SYMBOL_GPL(__clk_get_parent);
600 static struct clk_core *clk_core_get_parent_by_index(struct clk_core *clk,
603 if (!clk || index >= clk->num_parents)
605 else if (!clk->parents)
606 return clk_core_lookup(clk->parent_names[index]);
607 else if (!clk->parents[index])
608 return clk->parents[index] =
609 clk_core_lookup(clk->parent_names[index]);
611 return clk->parents[index];
614 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
616 struct clk_core *parent;
621 parent = clk_core_get_parent_by_index(clk->core, index);
623 return !parent ? NULL : parent->hw->clk;
625 EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
627 unsigned int __clk_get_enable_count(struct clk *clk)
629 return !clk ? 0 : clk->core->enable_count;
632 static unsigned long clk_core_get_rate_nolock(struct clk_core *clk)
643 if (clk->flags & CLK_IS_ROOT)
653 unsigned long __clk_get_rate(struct clk *clk)
658 return clk_core_get_rate_nolock(clk->core);
660 EXPORT_SYMBOL_GPL(__clk_get_rate);
662 static unsigned long __clk_get_accuracy(struct clk_core *clk)
667 return clk->accuracy;
670 unsigned long __clk_get_flags(struct clk *clk)
672 return !clk ? 0 : clk->core->flags;
674 EXPORT_SYMBOL_GPL(__clk_get_flags);
676 static bool clk_core_is_prepared(struct clk_core *clk)
684 * .is_prepared is optional for clocks that can prepare
685 * fall back to software usage counter if it is missing
687 if (!clk->ops->is_prepared) {
688 ret = clk->prepare_count ? 1 : 0;
692 ret = clk->ops->is_prepared(clk->hw);
697 bool __clk_is_prepared(struct clk *clk)
702 return clk_core_is_prepared(clk->core);
705 static bool clk_core_is_enabled(struct clk_core *clk)
713 * .is_enabled is only mandatory for clocks that gate
714 * fall back to software usage counter if .is_enabled is missing
716 if (!clk->ops->is_enabled) {
717 ret = clk->enable_count ? 1 : 0;
721 ret = clk->ops->is_enabled(clk->hw);
726 bool __clk_is_enabled(struct clk *clk)
731 return clk_core_is_enabled(clk->core);
733 EXPORT_SYMBOL_GPL(__clk_is_enabled);
735 static struct clk_core *__clk_lookup_subtree(const char *name,
736 struct clk_core *clk)
738 struct clk_core *child;
739 struct clk_core *ret;
741 if (!strcmp(clk->name, name))
744 hlist_for_each_entry(child, &clk->children, child_node) {
745 ret = __clk_lookup_subtree(name, child);
753 static struct clk_core *clk_core_lookup(const char *name)
755 struct clk_core *root_clk;
756 struct clk_core *ret;
761 /* search the 'proper' clk tree first */
762 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
763 ret = __clk_lookup_subtree(name, root_clk);
768 /* if not found, then search the orphan tree */
769 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
770 ret = __clk_lookup_subtree(name, root_clk);
778 static bool mux_is_better_rate(unsigned long rate, unsigned long now,
779 unsigned long best, unsigned long flags)
781 if (flags & CLK_MUX_ROUND_CLOSEST)
782 return abs(now - rate) < abs(best - rate);
784 return now <= rate && now > best;
788 clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate,
789 unsigned long min_rate,
790 unsigned long max_rate,
791 unsigned long *best_parent_rate,
792 struct clk_hw **best_parent_p,
795 struct clk_core *core = hw->core, *parent, *best_parent = NULL;
797 unsigned long parent_rate, best = 0;
799 /* if NO_REPARENT flag set, pass through to current parent */
800 if (core->flags & CLK_SET_RATE_NO_REPARENT) {
801 parent = core->parent;
802 if (core->flags & CLK_SET_RATE_PARENT)
803 best = __clk_determine_rate(parent ? parent->hw : NULL,
804 rate, min_rate, max_rate);
806 best = clk_core_get_rate_nolock(parent);
808 best = clk_core_get_rate_nolock(core);
812 /* find the parent that can provide the fastest rate <= rate */
813 num_parents = core->num_parents;
814 for (i = 0; i < num_parents; i++) {
815 parent = clk_core_get_parent_by_index(core, i);
818 if (core->flags & CLK_SET_RATE_PARENT)
819 parent_rate = __clk_determine_rate(parent->hw, rate,
823 parent_rate = clk_core_get_rate_nolock(parent);
824 if (mux_is_better_rate(rate, parent_rate, best, flags)) {
825 best_parent = parent;
832 *best_parent_p = best_parent->hw;
833 *best_parent_rate = best;
838 struct clk *__clk_lookup(const char *name)
840 struct clk_core *core = clk_core_lookup(name);
842 return !core ? NULL : core->hw->clk;
845 static void clk_core_get_boundaries(struct clk_core *clk,
846 unsigned long *min_rate,
847 unsigned long *max_rate)
849 struct clk *clk_user;
852 *max_rate = ULONG_MAX;
854 hlist_for_each_entry(clk_user, &clk->clks, child_node)
855 *min_rate = max(*min_rate, clk_user->min_rate);
857 hlist_for_each_entry(clk_user, &clk->clks, child_node)
858 *max_rate = min(*max_rate, clk_user->max_rate);
862 * Helper for finding best parent to provide a given frequency. This can be used
863 * directly as a determine_rate callback (e.g. for a mux), or from a more
864 * complex clock that may combine a mux with other operations.
866 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
867 unsigned long min_rate,
868 unsigned long max_rate,
869 unsigned long *best_parent_rate,
870 struct clk_hw **best_parent_p)
872 return clk_mux_determine_rate_flags(hw, rate, min_rate, max_rate,
876 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
878 long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
879 unsigned long min_rate,
880 unsigned long max_rate,
881 unsigned long *best_parent_rate,
882 struct clk_hw **best_parent_p)
884 return clk_mux_determine_rate_flags(hw, rate, min_rate, max_rate,
887 CLK_MUX_ROUND_CLOSEST);
889 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
893 static void clk_core_unprepare(struct clk_core *clk)
898 if (WARN_ON(clk->prepare_count == 0))
901 if (--clk->prepare_count > 0)
904 WARN_ON(clk->enable_count > 0);
906 if (clk->ops->unprepare)
907 clk->ops->unprepare(clk->hw);
909 clk_core_unprepare(clk->parent);
913 * clk_unprepare - undo preparation of a clock source
914 * @clk: the clk being unprepared
916 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
917 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
918 * if the operation may sleep. One example is a clk which is accessed over
919 * I2c. In the complex case a clk gate operation may require a fast and a slow
920 * part. It is this reason that clk_unprepare and clk_disable are not mutually
921 * exclusive. In fact clk_disable must be called before clk_unprepare.
923 void clk_unprepare(struct clk *clk)
925 if (IS_ERR_OR_NULL(clk))
929 clk_core_unprepare(clk->core);
930 clk_prepare_unlock();
932 EXPORT_SYMBOL_GPL(clk_unprepare);
934 static int clk_core_prepare(struct clk_core *clk)
941 if (clk->prepare_count == 0) {
942 ret = clk_core_prepare(clk->parent);
946 if (clk->ops->prepare) {
947 ret = clk->ops->prepare(clk->hw);
949 clk_core_unprepare(clk->parent);
955 clk->prepare_count++;
961 * clk_prepare - prepare a clock source
962 * @clk: the clk being prepared
964 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
965 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
966 * operation may sleep. One example is a clk which is accessed over I2c. In
967 * the complex case a clk ungate operation may require a fast and a slow part.
968 * It is this reason that clk_prepare and clk_enable are not mutually
969 * exclusive. In fact clk_prepare must be called before clk_enable.
970 * Returns 0 on success, -EERROR otherwise.
972 int clk_prepare(struct clk *clk)
980 ret = clk_core_prepare(clk->core);
981 clk_prepare_unlock();
985 EXPORT_SYMBOL_GPL(clk_prepare);
987 static void clk_core_disable(struct clk_core *clk)
992 if (WARN_ON(clk->enable_count == 0))
995 if (--clk->enable_count > 0)
998 if (clk->ops->disable)
999 clk->ops->disable(clk->hw);
1001 clk_core_disable(clk->parent);
1004 static void __clk_disable(struct clk *clk)
1009 clk_core_disable(clk->core);
1013 * clk_disable - gate a clock
1014 * @clk: the clk being gated
1016 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
1017 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
1018 * clk if the operation is fast and will never sleep. One example is a
1019 * SoC-internal clk which is controlled via simple register writes. In the
1020 * complex case a clk gate operation may require a fast and a slow part. It is
1021 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
1022 * In fact clk_disable must be called before clk_unprepare.
1024 void clk_disable(struct clk *clk)
1026 unsigned long flags;
1028 if (IS_ERR_OR_NULL(clk))
1031 flags = clk_enable_lock();
1033 clk_enable_unlock(flags);
1035 EXPORT_SYMBOL_GPL(clk_disable);
1037 static int clk_core_enable(struct clk_core *clk)
1044 if (WARN_ON(clk->prepare_count == 0))
1047 if (clk->enable_count == 0) {
1048 ret = clk_core_enable(clk->parent);
1053 if (clk->ops->enable) {
1054 ret = clk->ops->enable(clk->hw);
1056 clk_core_disable(clk->parent);
1062 clk->enable_count++;
1066 static int __clk_enable(struct clk *clk)
1071 return clk_core_enable(clk->core);
1075 * clk_enable - ungate a clock
1076 * @clk: the clk being ungated
1078 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
1079 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
1080 * if the operation will never sleep. One example is a SoC-internal clk which
1081 * is controlled via simple register writes. In the complex case a clk ungate
1082 * operation may require a fast and a slow part. It is this reason that
1083 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
1084 * must be called before clk_enable. Returns 0 on success, -EERROR
1087 int clk_enable(struct clk *clk)
1089 unsigned long flags;
1092 flags = clk_enable_lock();
1093 ret = __clk_enable(clk);
1094 clk_enable_unlock(flags);
1098 EXPORT_SYMBOL_GPL(clk_enable);
1100 static unsigned long clk_core_round_rate_nolock(struct clk_core *clk,
1102 unsigned long min_rate,
1103 unsigned long max_rate)
1105 unsigned long parent_rate = 0;
1106 struct clk_core *parent;
1107 struct clk_hw *parent_hw;
1112 parent = clk->parent;
1114 parent_rate = parent->rate;
1116 if (clk->ops->determine_rate) {
1117 parent_hw = parent ? parent->hw : NULL;
1118 return clk->ops->determine_rate(clk->hw, rate,
1120 &parent_rate, &parent_hw);
1121 } else if (clk->ops->round_rate)
1122 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
1123 else if (clk->flags & CLK_SET_RATE_PARENT)
1124 return clk_core_round_rate_nolock(clk->parent, rate, min_rate,
1131 * __clk_determine_rate - get the closest rate actually supported by a clock
1132 * @hw: determine the rate of this clock
1133 * @rate: target rate
1134 * @min_rate: returned rate must be greater than this rate
1135 * @max_rate: returned rate must be less than this rate
1137 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate and
1140 unsigned long __clk_determine_rate(struct clk_hw *hw,
1142 unsigned long min_rate,
1143 unsigned long max_rate)
1148 return clk_core_round_rate_nolock(hw->core, rate, min_rate, max_rate);
1150 EXPORT_SYMBOL_GPL(__clk_determine_rate);
1153 * __clk_round_rate - round the given rate for a clk
1154 * @clk: round the rate of this clock
1155 * @rate: the rate which is to be rounded
1157 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
1159 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
1161 unsigned long min_rate;
1162 unsigned long max_rate;
1167 clk_core_get_boundaries(clk->core, &min_rate, &max_rate);
1169 return clk_core_round_rate_nolock(clk->core, rate, min_rate, max_rate);
1171 EXPORT_SYMBOL_GPL(__clk_round_rate);
1174 * clk_round_rate - round the given rate for a clk
1175 * @clk: the clk for which we are rounding a rate
1176 * @rate: the rate which is to be rounded
1178 * Takes in a rate as input and rounds it to a rate that the clk can actually
1179 * use which is then returned. If clk doesn't support round_rate operation
1180 * then the parent rate is returned.
1182 long clk_round_rate(struct clk *clk, unsigned long rate)
1190 ret = __clk_round_rate(clk, rate);
1191 clk_prepare_unlock();
1195 EXPORT_SYMBOL_GPL(clk_round_rate);
1198 * __clk_notify - call clk notifier chain
1199 * @clk: struct clk * that is changing rate
1200 * @msg: clk notifier type (see include/linux/clk.h)
1201 * @old_rate: old clk rate
1202 * @new_rate: new clk rate
1204 * Triggers a notifier call chain on the clk rate-change notification
1205 * for 'clk'. Passes a pointer to the struct clk and the previous
1206 * and current rates to the notifier callback. Intended to be called by
1207 * internal clock code only. Returns NOTIFY_DONE from the last driver
1208 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1209 * a driver returns that.
1211 static int __clk_notify(struct clk_core *clk, unsigned long msg,
1212 unsigned long old_rate, unsigned long new_rate)
1214 struct clk_notifier *cn;
1215 struct clk_notifier_data cnd;
1216 int ret = NOTIFY_DONE;
1218 cnd.old_rate = old_rate;
1219 cnd.new_rate = new_rate;
1221 list_for_each_entry(cn, &clk_notifier_list, node) {
1222 if (cn->clk->core == clk) {
1224 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1233 * __clk_recalc_accuracies
1234 * @clk: first clk in the subtree
1236 * Walks the subtree of clks starting with clk and recalculates accuracies as
1237 * it goes. Note that if a clk does not implement the .recalc_accuracy
1238 * callback then it is assumed that the clock will take on the accuracy of it's
1241 * Caller must hold prepare_lock.
1243 static void __clk_recalc_accuracies(struct clk_core *clk)
1245 unsigned long parent_accuracy = 0;
1246 struct clk_core *child;
1249 parent_accuracy = clk->parent->accuracy;
1251 if (clk->ops->recalc_accuracy)
1252 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1255 clk->accuracy = parent_accuracy;
1257 hlist_for_each_entry(child, &clk->children, child_node)
1258 __clk_recalc_accuracies(child);
1261 static long clk_core_get_accuracy(struct clk_core *clk)
1263 unsigned long accuracy;
1266 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1267 __clk_recalc_accuracies(clk);
1269 accuracy = __clk_get_accuracy(clk);
1270 clk_prepare_unlock();
1276 * clk_get_accuracy - return the accuracy of clk
1277 * @clk: the clk whose accuracy is being returned
1279 * Simply returns the cached accuracy of the clk, unless
1280 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1282 * If clk is NULL then returns 0.
1284 long clk_get_accuracy(struct clk *clk)
1289 return clk_core_get_accuracy(clk->core);
1291 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1293 static unsigned long clk_recalc(struct clk_core *clk,
1294 unsigned long parent_rate)
1296 if (clk->ops->recalc_rate)
1297 return clk->ops->recalc_rate(clk->hw, parent_rate);
1302 * __clk_recalc_rates
1303 * @clk: first clk in the subtree
1304 * @msg: notification type (see include/linux/clk.h)
1306 * Walks the subtree of clks starting with clk and recalculates rates as it
1307 * goes. Note that if a clk does not implement the .recalc_rate callback then
1308 * it is assumed that the clock will take on the rate of its parent.
1310 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1313 * Caller must hold prepare_lock.
1315 static void __clk_recalc_rates(struct clk_core *clk, unsigned long msg)
1317 unsigned long old_rate;
1318 unsigned long parent_rate = 0;
1319 struct clk_core *child;
1321 old_rate = clk->rate;
1324 parent_rate = clk->parent->rate;
1326 clk->rate = clk_recalc(clk, parent_rate);
1329 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1330 * & ABORT_RATE_CHANGE notifiers
1332 if (clk->notifier_count && msg)
1333 __clk_notify(clk, msg, old_rate, clk->rate);
1335 hlist_for_each_entry(child, &clk->children, child_node)
1336 __clk_recalc_rates(child, msg);
1339 static unsigned long clk_core_get_rate(struct clk_core *clk)
1345 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1346 __clk_recalc_rates(clk, 0);
1348 rate = clk_core_get_rate_nolock(clk);
1349 clk_prepare_unlock();
1355 * clk_get_rate - return the rate of clk
1356 * @clk: the clk whose rate is being returned
1358 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1359 * is set, which means a recalc_rate will be issued.
1360 * If clk is NULL then returns 0.
1362 unsigned long clk_get_rate(struct clk *clk)
1367 return clk_core_get_rate(clk->core);
1369 EXPORT_SYMBOL_GPL(clk_get_rate);
1371 static int clk_fetch_parent_index(struct clk_core *clk,
1372 struct clk_core *parent)
1376 if (!clk->parents) {
1377 clk->parents = kcalloc(clk->num_parents,
1378 sizeof(struct clk *), GFP_KERNEL);
1384 * find index of new parent clock using cached parent ptrs,
1385 * or if not yet cached, use string name comparison and cache
1386 * them now to avoid future calls to clk_core_lookup.
1388 for (i = 0; i < clk->num_parents; i++) {
1389 if (clk->parents[i] == parent)
1392 if (clk->parents[i])
1395 if (!strcmp(clk->parent_names[i], parent->name)) {
1396 clk->parents[i] = clk_core_lookup(parent->name);
1404 static void clk_reparent(struct clk_core *clk, struct clk_core *new_parent)
1406 hlist_del(&clk->child_node);
1409 /* avoid duplicate POST_RATE_CHANGE notifications */
1410 if (new_parent->new_child == clk)
1411 new_parent->new_child = NULL;
1413 hlist_add_head(&clk->child_node, &new_parent->children);
1415 hlist_add_head(&clk->child_node, &clk_orphan_list);
1418 clk->parent = new_parent;
1421 static struct clk_core *__clk_set_parent_before(struct clk_core *clk,
1422 struct clk_core *parent)
1424 unsigned long flags;
1425 struct clk_core *old_parent = clk->parent;
1428 * Migrate prepare state between parents and prevent race with
1431 * If the clock is not prepared, then a race with
1432 * clk_enable/disable() is impossible since we already have the
1433 * prepare lock (future calls to clk_enable() need to be preceded by
1436 * If the clock is prepared, migrate the prepared state to the new
1437 * parent and also protect against a race with clk_enable() by
1438 * forcing the clock and the new parent on. This ensures that all
1439 * future calls to clk_enable() are practically NOPs with respect to
1440 * hardware and software states.
1442 * See also: Comment for clk_set_parent() below.
1444 if (clk->prepare_count) {
1445 clk_core_prepare(parent);
1446 clk_core_enable(parent);
1447 clk_core_enable(clk);
1450 /* update the clk tree topology */
1451 flags = clk_enable_lock();
1452 clk_reparent(clk, parent);
1453 clk_enable_unlock(flags);
1458 static void __clk_set_parent_after(struct clk_core *core,
1459 struct clk_core *parent,
1460 struct clk_core *old_parent)
1463 * Finish the migration of prepare state and undo the changes done
1464 * for preventing a race with clk_enable().
1466 if (core->prepare_count) {
1467 clk_core_disable(core);
1468 clk_core_disable(old_parent);
1469 clk_core_unprepare(old_parent);
1473 static int __clk_set_parent(struct clk_core *clk, struct clk_core *parent,
1476 unsigned long flags;
1478 struct clk_core *old_parent;
1480 old_parent = __clk_set_parent_before(clk, parent);
1482 /* change clock input source */
1483 if (parent && clk->ops->set_parent)
1484 ret = clk->ops->set_parent(clk->hw, p_index);
1487 flags = clk_enable_lock();
1488 clk_reparent(clk, old_parent);
1489 clk_enable_unlock(flags);
1491 if (clk->prepare_count) {
1492 clk_core_disable(clk);
1493 clk_core_disable(parent);
1494 clk_core_unprepare(parent);
1499 __clk_set_parent_after(clk, parent, old_parent);
1505 * __clk_speculate_rates
1506 * @clk: first clk in the subtree
1507 * @parent_rate: the "future" rate of clk's parent
1509 * Walks the subtree of clks starting with clk, speculating rates as it
1510 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1512 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1513 * pre-rate change notifications and returns early if no clks in the
1514 * subtree have subscribed to the notifications. Note that if a clk does not
1515 * implement the .recalc_rate callback then it is assumed that the clock will
1516 * take on the rate of its parent.
1518 * Caller must hold prepare_lock.
1520 static int __clk_speculate_rates(struct clk_core *clk,
1521 unsigned long parent_rate)
1523 struct clk_core *child;
1524 unsigned long new_rate;
1525 int ret = NOTIFY_DONE;
1527 new_rate = clk_recalc(clk, parent_rate);
1529 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1530 if (clk->notifier_count)
1531 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1533 if (ret & NOTIFY_STOP_MASK) {
1534 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1535 __func__, clk->name, ret);
1539 hlist_for_each_entry(child, &clk->children, child_node) {
1540 ret = __clk_speculate_rates(child, new_rate);
1541 if (ret & NOTIFY_STOP_MASK)
1549 static void clk_calc_subtree(struct clk_core *clk, unsigned long new_rate,
1550 struct clk_core *new_parent, u8 p_index)
1552 struct clk_core *child;
1554 clk->new_rate = new_rate;
1555 clk->new_parent = new_parent;
1556 clk->new_parent_index = p_index;
1557 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1558 clk->new_child = NULL;
1559 if (new_parent && new_parent != clk->parent)
1560 new_parent->new_child = clk;
1562 hlist_for_each_entry(child, &clk->children, child_node) {
1563 child->new_rate = clk_recalc(child, new_rate);
1564 clk_calc_subtree(child, child->new_rate, NULL, 0);
1569 * calculate the new rates returning the topmost clock that has to be
1572 static struct clk_core *clk_calc_new_rates(struct clk_core *clk,
1575 struct clk_core *top = clk;
1576 struct clk_core *old_parent, *parent;
1577 struct clk_hw *parent_hw;
1578 unsigned long best_parent_rate = 0;
1579 unsigned long new_rate;
1580 unsigned long min_rate;
1581 unsigned long max_rate;
1585 if (IS_ERR_OR_NULL(clk))
1588 /* save parent rate, if it exists */
1589 parent = old_parent = clk->parent;
1591 best_parent_rate = parent->rate;
1593 clk_core_get_boundaries(clk, &min_rate, &max_rate);
1595 /* find the closest rate and parent clk/rate */
1596 if (clk->ops->determine_rate) {
1597 parent_hw = parent ? parent->hw : NULL;
1598 new_rate = clk->ops->determine_rate(clk->hw, rate,
1603 parent = parent_hw ? parent_hw->core : NULL;
1604 } else if (clk->ops->round_rate) {
1605 new_rate = clk->ops->round_rate(clk->hw, rate,
1607 if (new_rate < min_rate || new_rate > max_rate)
1609 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1610 /* pass-through clock without adjustable parent */
1611 clk->new_rate = clk->rate;
1614 /* pass-through clock with adjustable parent */
1615 top = clk_calc_new_rates(parent, rate);
1616 new_rate = parent->new_rate;
1620 /* some clocks must be gated to change parent */
1621 if (parent != old_parent &&
1622 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1623 pr_debug("%s: %s not gated but wants to reparent\n",
1624 __func__, clk->name);
1628 /* try finding the new parent index */
1629 if (parent && clk->num_parents > 1) {
1630 p_index = clk_fetch_parent_index(clk, parent);
1632 pr_debug("%s: clk %s can not be parent of clk %s\n",
1633 __func__, parent->name, clk->name);
1638 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1639 best_parent_rate != parent->rate)
1640 top = clk_calc_new_rates(parent, best_parent_rate);
1643 clk_calc_subtree(clk, new_rate, parent, p_index);
1649 * Notify about rate changes in a subtree. Always walk down the whole tree
1650 * so that in case of an error we can walk down the whole tree again and
1653 static struct clk_core *clk_propagate_rate_change(struct clk_core *clk,
1654 unsigned long event)
1656 struct clk_core *child, *tmp_clk, *fail_clk = NULL;
1657 int ret = NOTIFY_DONE;
1659 if (clk->rate == clk->new_rate)
1662 if (clk->notifier_count) {
1663 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1664 if (ret & NOTIFY_STOP_MASK)
1668 hlist_for_each_entry(child, &clk->children, child_node) {
1669 /* Skip children who will be reparented to another clock */
1670 if (child->new_parent && child->new_parent != clk)
1672 tmp_clk = clk_propagate_rate_change(child, event);
1677 /* handle the new child who might not be in clk->children yet */
1678 if (clk->new_child) {
1679 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1688 * walk down a subtree and set the new rates notifying the rate
1691 static void clk_change_rate(struct clk_core *clk)
1693 struct clk_core *child;
1694 struct hlist_node *tmp;
1695 unsigned long old_rate;
1696 unsigned long best_parent_rate = 0;
1697 bool skip_set_rate = false;
1698 struct clk_core *old_parent;
1700 old_rate = clk->rate;
1702 if (clk->new_parent)
1703 best_parent_rate = clk->new_parent->rate;
1704 else if (clk->parent)
1705 best_parent_rate = clk->parent->rate;
1707 if (clk->new_parent && clk->new_parent != clk->parent) {
1708 old_parent = __clk_set_parent_before(clk, clk->new_parent);
1710 if (clk->ops->set_rate_and_parent) {
1711 skip_set_rate = true;
1712 clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
1714 clk->new_parent_index);
1715 } else if (clk->ops->set_parent) {
1716 clk->ops->set_parent(clk->hw, clk->new_parent_index);
1719 __clk_set_parent_after(clk, clk->new_parent, old_parent);
1722 if (!skip_set_rate && clk->ops->set_rate)
1723 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1725 clk->rate = clk_recalc(clk, best_parent_rate);
1727 if (clk->notifier_count && old_rate != clk->rate)
1728 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1731 * Use safe iteration, as change_rate can actually swap parents
1732 * for certain clock types.
1734 hlist_for_each_entry_safe(child, tmp, &clk->children, child_node) {
1735 /* Skip children who will be reparented to another clock */
1736 if (child->new_parent && child->new_parent != clk)
1738 clk_change_rate(child);
1741 /* handle the new child who might not be in clk->children yet */
1743 clk_change_rate(clk->new_child);
1746 static int clk_core_set_rate_nolock(struct clk_core *clk,
1747 unsigned long req_rate)
1749 struct clk_core *top, *fail_clk;
1750 unsigned long rate = req_rate;
1756 /* bail early if nothing to do */
1757 if (rate == clk_core_get_rate_nolock(clk))
1760 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count)
1763 /* calculate new rates and get the topmost changed clock */
1764 top = clk_calc_new_rates(clk, rate);
1768 /* notify that we are about to change rates */
1769 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1771 pr_debug("%s: failed to set %s rate\n", __func__,
1773 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1777 /* change the rates */
1778 clk_change_rate(top);
1780 clk->req_rate = req_rate;
1786 * clk_set_rate - specify a new rate for clk
1787 * @clk: the clk whose rate is being changed
1788 * @rate: the new rate for clk
1790 * In the simplest case clk_set_rate will only adjust the rate of clk.
1792 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1793 * propagate up to clk's parent; whether or not this happens depends on the
1794 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1795 * after calling .round_rate then upstream parent propagation is ignored. If
1796 * *parent_rate comes back with a new rate for clk's parent then we propagate
1797 * up to clk's parent and set its rate. Upward propagation will continue
1798 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1799 * .round_rate stops requesting changes to clk's parent_rate.
1801 * Rate changes are accomplished via tree traversal that also recalculates the
1802 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1804 * Returns 0 on success, -EERROR otherwise.
1806 int clk_set_rate(struct clk *clk, unsigned long rate)
1813 /* prevent racing with updates to the clock topology */
1816 ret = clk_core_set_rate_nolock(clk->core, rate);
1818 clk_prepare_unlock();
1822 EXPORT_SYMBOL_GPL(clk_set_rate);
1825 * clk_set_rate_range - set a rate range for a clock source
1826 * @clk: clock source
1827 * @min: desired minimum clock rate in Hz, inclusive
1828 * @max: desired maximum clock rate in Hz, inclusive
1830 * Returns success (0) or negative errno.
1832 int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
1840 pr_err("%s: clk %s dev %s con %s: invalid range [%lu, %lu]\n",
1841 __func__, clk->core->name, clk->dev_id, clk->con_id,
1848 if (min != clk->min_rate || max != clk->max_rate) {
1849 clk->min_rate = min;
1850 clk->max_rate = max;
1851 ret = clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
1854 clk_prepare_unlock();
1858 EXPORT_SYMBOL_GPL(clk_set_rate_range);
1861 * clk_set_min_rate - set a minimum clock rate for a clock source
1862 * @clk: clock source
1863 * @rate: desired minimum clock rate in Hz, inclusive
1865 * Returns success (0) or negative errno.
1867 int clk_set_min_rate(struct clk *clk, unsigned long rate)
1872 return clk_set_rate_range(clk, rate, clk->max_rate);
1874 EXPORT_SYMBOL_GPL(clk_set_min_rate);
1877 * clk_set_max_rate - set a maximum clock rate for a clock source
1878 * @clk: clock source
1879 * @rate: desired maximum clock rate in Hz, inclusive
1881 * Returns success (0) or negative errno.
1883 int clk_set_max_rate(struct clk *clk, unsigned long rate)
1888 return clk_set_rate_range(clk, clk->min_rate, rate);
1890 EXPORT_SYMBOL_GPL(clk_set_max_rate);
1893 * clk_get_parent - return the parent of a clk
1894 * @clk: the clk whose parent gets returned
1896 * Simply returns clk->parent. Returns NULL if clk is NULL.
1898 struct clk *clk_get_parent(struct clk *clk)
1903 parent = __clk_get_parent(clk);
1904 clk_prepare_unlock();
1908 EXPORT_SYMBOL_GPL(clk_get_parent);
1911 * .get_parent is mandatory for clocks with multiple possible parents. It is
1912 * optional for single-parent clocks. Always call .get_parent if it is
1913 * available and WARN if it is missing for multi-parent clocks.
1915 * For single-parent clocks without .get_parent, first check to see if the
1916 * .parents array exists, and if so use it to avoid an expensive tree
1917 * traversal. If .parents does not exist then walk the tree.
1919 static struct clk_core *__clk_init_parent(struct clk_core *clk)
1921 struct clk_core *ret = NULL;
1924 /* handle the trivial cases */
1926 if (!clk->num_parents)
1929 if (clk->num_parents == 1) {
1930 if (IS_ERR_OR_NULL(clk->parent))
1931 clk->parent = clk_core_lookup(clk->parent_names[0]);
1936 if (!clk->ops->get_parent) {
1937 WARN(!clk->ops->get_parent,
1938 "%s: multi-parent clocks must implement .get_parent\n",
1944 * Do our best to cache parent clocks in clk->parents. This prevents
1945 * unnecessary and expensive lookups. We don't set clk->parent here;
1946 * that is done by the calling function.
1949 index = clk->ops->get_parent(clk->hw);
1953 kcalloc(clk->num_parents, sizeof(struct clk *),
1956 ret = clk_core_get_parent_by_index(clk, index);
1962 static void clk_core_reparent(struct clk_core *clk,
1963 struct clk_core *new_parent)
1965 clk_reparent(clk, new_parent);
1966 __clk_recalc_accuracies(clk);
1967 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1971 * clk_has_parent - check if a clock is a possible parent for another
1972 * @clk: clock source
1973 * @parent: parent clock source
1975 * This function can be used in drivers that need to check that a clock can be
1976 * the parent of another without actually changing the parent.
1978 * Returns true if @parent is a possible parent for @clk, false otherwise.
1980 bool clk_has_parent(struct clk *clk, struct clk *parent)
1982 struct clk_core *core, *parent_core;
1985 /* NULL clocks should be nops, so return success if either is NULL. */
1986 if (!clk || !parent)
1990 parent_core = parent->core;
1992 /* Optimize for the case where the parent is already the parent. */
1993 if (core->parent == parent_core)
1996 for (i = 0; i < core->num_parents; i++)
1997 if (strcmp(core->parent_names[i], parent_core->name) == 0)
2002 EXPORT_SYMBOL_GPL(clk_has_parent);
2004 static int clk_core_set_parent(struct clk_core *clk, struct clk_core *parent)
2008 unsigned long p_rate = 0;
2013 /* verify ops for for multi-parent clks */
2014 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
2017 /* prevent racing with updates to the clock topology */
2020 if (clk->parent == parent)
2023 /* check that we are allowed to re-parent if the clock is in use */
2024 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
2029 /* try finding the new parent index */
2031 p_index = clk_fetch_parent_index(clk, parent);
2032 p_rate = parent->rate;
2034 pr_debug("%s: clk %s can not be parent of clk %s\n",
2035 __func__, parent->name, clk->name);
2041 /* propagate PRE_RATE_CHANGE notifications */
2042 ret = __clk_speculate_rates(clk, p_rate);
2044 /* abort if a driver objects */
2045 if (ret & NOTIFY_STOP_MASK)
2048 /* do the re-parent */
2049 ret = __clk_set_parent(clk, parent, p_index);
2051 /* propagate rate an accuracy recalculation accordingly */
2053 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
2055 __clk_recalc_rates(clk, POST_RATE_CHANGE);
2056 __clk_recalc_accuracies(clk);
2060 clk_prepare_unlock();
2066 * clk_set_parent - switch the parent of a mux clk
2067 * @clk: the mux clk whose input we are switching
2068 * @parent: the new input to clk
2070 * Re-parent clk to use parent as its new input source. If clk is in
2071 * prepared state, the clk will get enabled for the duration of this call. If
2072 * that's not acceptable for a specific clk (Eg: the consumer can't handle
2073 * that, the reparenting is glitchy in hardware, etc), use the
2074 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
2076 * After successfully changing clk's parent clk_set_parent will update the
2077 * clk topology, sysfs topology and propagate rate recalculation via
2078 * __clk_recalc_rates.
2080 * Returns 0 on success, -EERROR otherwise.
2082 int clk_set_parent(struct clk *clk, struct clk *parent)
2087 return clk_core_set_parent(clk->core, parent ? parent->core : NULL);
2089 EXPORT_SYMBOL_GPL(clk_set_parent);
2092 * clk_set_phase - adjust the phase shift of a clock signal
2093 * @clk: clock signal source
2094 * @degrees: number of degrees the signal is shifted
2096 * Shifts the phase of a clock signal by the specified
2097 * degrees. Returns 0 on success, -EERROR otherwise.
2099 * This function makes no distinction about the input or reference
2100 * signal that we adjust the clock signal phase against. For example
2101 * phase locked-loop clock signal generators we may shift phase with
2102 * respect to feedback clock signal input, but for other cases the
2103 * clock phase may be shifted with respect to some other, unspecified
2106 * Additionally the concept of phase shift does not propagate through
2107 * the clock tree hierarchy, which sets it apart from clock rates and
2108 * clock accuracy. A parent clock phase attribute does not have an
2109 * impact on the phase attribute of a child clock.
2111 int clk_set_phase(struct clk *clk, int degrees)
2118 /* sanity check degrees */
2125 if (!clk->core->ops->set_phase)
2128 ret = clk->core->ops->set_phase(clk->core->hw, degrees);
2131 clk->core->phase = degrees;
2134 clk_prepare_unlock();
2139 EXPORT_SYMBOL_GPL(clk_set_phase);
2141 static int clk_core_get_phase(struct clk_core *clk)
2150 clk_prepare_unlock();
2155 EXPORT_SYMBOL_GPL(clk_get_phase);
2158 * clk_get_phase - return the phase shift of a clock signal
2159 * @clk: clock signal source
2161 * Returns the phase shift of a clock node in degrees, otherwise returns
2164 int clk_get_phase(struct clk *clk)
2169 return clk_core_get_phase(clk->core);
2173 * clk_is_match - check if two clk's point to the same hardware clock
2174 * @p: clk compared against q
2175 * @q: clk compared against p
2177 * Returns true if the two struct clk pointers both point to the same hardware
2178 * clock node. Put differently, returns true if struct clk *p and struct clk *q
2179 * share the same struct clk_core object.
2181 * Returns false otherwise. Note that two NULL clks are treated as matching.
2183 bool clk_is_match(const struct clk *p, const struct clk *q)
2185 /* trivial case: identical struct clk's or both NULL */
2189 /* true if clk->core pointers match. Avoid derefing garbage */
2190 if (!IS_ERR_OR_NULL(p) && !IS_ERR_OR_NULL(q))
2191 if (p->core == q->core)
2196 EXPORT_SYMBOL_GPL(clk_is_match);
2199 * __clk_init - initialize the data structures in a struct clk
2200 * @dev: device initializing this clk, placeholder for now
2201 * @clk: clk being initialized
2203 * Initializes the lists in struct clk_core, queries the hardware for the
2204 * parent and rate and sets them both.
2206 static int __clk_init(struct device *dev, struct clk *clk_user)
2209 struct clk_core *orphan;
2210 struct hlist_node *tmp2;
2211 struct clk_core *clk;
2217 clk = clk_user->core;
2221 /* check to see if a clock with this name is already registered */
2222 if (clk_core_lookup(clk->name)) {
2223 pr_debug("%s: clk %s already initialized\n",
2224 __func__, clk->name);
2229 /* check that clk_ops are sane. See Documentation/clk.txt */
2230 if (clk->ops->set_rate &&
2231 !((clk->ops->round_rate || clk->ops->determine_rate) &&
2232 clk->ops->recalc_rate)) {
2233 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
2234 __func__, clk->name);
2239 if (clk->ops->set_parent && !clk->ops->get_parent) {
2240 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
2241 __func__, clk->name);
2246 if (clk->ops->set_rate_and_parent &&
2247 !(clk->ops->set_parent && clk->ops->set_rate)) {
2248 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
2249 __func__, clk->name);
2254 /* throw a WARN if any entries in parent_names are NULL */
2255 for (i = 0; i < clk->num_parents; i++)
2256 WARN(!clk->parent_names[i],
2257 "%s: invalid NULL in %s's .parent_names\n",
2258 __func__, clk->name);
2261 * Allocate an array of struct clk *'s to avoid unnecessary string
2262 * look-ups of clk's possible parents. This can fail for clocks passed
2263 * in to clk_init during early boot; thus any access to clk->parents[]
2264 * must always check for a NULL pointer and try to populate it if
2267 * If clk->parents is not NULL we skip this entire block. This allows
2268 * for clock drivers to statically initialize clk->parents.
2270 if (clk->num_parents > 1 && !clk->parents) {
2271 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
2274 * clk_core_lookup returns NULL for parents that have not been
2275 * clk_init'd; thus any access to clk->parents[] must check
2276 * for a NULL pointer. We can always perform lazy lookups for
2277 * missing parents later on.
2280 for (i = 0; i < clk->num_parents; i++)
2282 clk_core_lookup(clk->parent_names[i]);
2285 clk->parent = __clk_init_parent(clk);
2288 * Populate clk->parent if parent has already been __clk_init'd. If
2289 * parent has not yet been __clk_init'd then place clk in the orphan
2290 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
2293 * Every time a new clk is clk_init'd then we walk the list of orphan
2294 * clocks and re-parent any that are children of the clock currently
2298 hlist_add_head(&clk->child_node,
2299 &clk->parent->children);
2300 else if (clk->flags & CLK_IS_ROOT)
2301 hlist_add_head(&clk->child_node, &clk_root_list);
2303 hlist_add_head(&clk->child_node, &clk_orphan_list);
2306 * Set clk's accuracy. The preferred method is to use
2307 * .recalc_accuracy. For simple clocks and lazy developers the default
2308 * fallback is to use the parent's accuracy. If a clock doesn't have a
2309 * parent (or is orphaned) then accuracy is set to zero (perfect
2312 if (clk->ops->recalc_accuracy)
2313 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
2314 __clk_get_accuracy(clk->parent));
2315 else if (clk->parent)
2316 clk->accuracy = clk->parent->accuracy;
2322 * Since a phase is by definition relative to its parent, just
2323 * query the current clock phase, or just assume it's in phase.
2325 if (clk->ops->get_phase)
2326 clk->phase = clk->ops->get_phase(clk->hw);
2331 * Set clk's rate. The preferred method is to use .recalc_rate. For
2332 * simple clocks and lazy developers the default fallback is to use the
2333 * parent's rate. If a clock doesn't have a parent (or is orphaned)
2334 * then rate is set to zero.
2336 if (clk->ops->recalc_rate)
2337 rate = clk->ops->recalc_rate(clk->hw,
2338 clk_core_get_rate_nolock(clk->parent));
2339 else if (clk->parent)
2340 rate = clk->parent->rate;
2343 clk->rate = clk->req_rate = rate;
2346 * walk the list of orphan clocks and reparent any that are children of
2349 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
2350 if (orphan->num_parents && orphan->ops->get_parent) {
2351 i = orphan->ops->get_parent(orphan->hw);
2352 if (!strcmp(clk->name, orphan->parent_names[i]))
2353 clk_core_reparent(orphan, clk);
2357 for (i = 0; i < orphan->num_parents; i++)
2358 if (!strcmp(clk->name, orphan->parent_names[i])) {
2359 clk_core_reparent(orphan, clk);
2365 * optional platform-specific magic
2367 * The .init callback is not used by any of the basic clock types, but
2368 * exists for weird hardware that must perform initialization magic.
2369 * Please consider other ways of solving initialization problems before
2370 * using this callback, as its use is discouraged.
2373 clk->ops->init(clk->hw);
2375 kref_init(&clk->ref);
2377 clk_prepare_unlock();
2380 clk_debug_register(clk);
2385 struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
2390 /* This is to allow this function to be chained to others */
2391 if (!hw || IS_ERR(hw))
2392 return (struct clk *) hw;
2394 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2396 return ERR_PTR(-ENOMEM);
2398 clk->core = hw->core;
2399 clk->dev_id = dev_id;
2400 clk->con_id = con_id;
2401 clk->max_rate = ULONG_MAX;
2404 hlist_add_head(&clk->child_node, &hw->core->clks);
2405 clk_prepare_unlock();
2410 void __clk_free_clk(struct clk *clk)
2413 hlist_del(&clk->child_node);
2414 clk_prepare_unlock();
2420 * clk_register - allocate a new clock, register it and return an opaque cookie
2421 * @dev: device that is registering this clock
2422 * @hw: link to hardware-specific clock data
2424 * clk_register is the primary interface for populating the clock tree with new
2425 * clock nodes. It returns a pointer to the newly allocated struct clk which
2426 * cannot be dereferenced by driver code but may be used in conjuction with the
2427 * rest of the clock API. In the event of an error clk_register will return an
2428 * error code; drivers must test for an error code after calling clk_register.
2430 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
2433 struct clk_core *clk;
2435 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2437 pr_err("%s: could not allocate clk\n", __func__);
2442 clk->name = kstrdup_const(hw->init->name, GFP_KERNEL);
2444 pr_err("%s: could not allocate clk->name\n", __func__);
2448 clk->ops = hw->init->ops;
2449 if (dev && dev->driver)
2450 clk->owner = dev->driver->owner;
2452 clk->flags = hw->init->flags;
2453 clk->num_parents = hw->init->num_parents;
2456 /* allocate local copy in case parent_names is __initdata */
2457 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
2460 if (!clk->parent_names) {
2461 pr_err("%s: could not allocate clk->parent_names\n", __func__);
2463 goto fail_parent_names;
2467 /* copy each string name in case parent_names is __initdata */
2468 for (i = 0; i < clk->num_parents; i++) {
2469 clk->parent_names[i] = kstrdup_const(hw->init->parent_names[i],
2471 if (!clk->parent_names[i]) {
2472 pr_err("%s: could not copy parent_names\n", __func__);
2474 goto fail_parent_names_copy;
2478 INIT_HLIST_HEAD(&clk->clks);
2480 hw->clk = __clk_create_clk(hw, NULL, NULL);
2481 if (IS_ERR(hw->clk)) {
2482 pr_err("%s: could not allocate per-user clk\n", __func__);
2483 ret = PTR_ERR(hw->clk);
2484 goto fail_parent_names_copy;
2487 ret = __clk_init(dev, hw->clk);
2491 __clk_free_clk(hw->clk);
2494 fail_parent_names_copy:
2496 kfree_const(clk->parent_names[i]);
2497 kfree(clk->parent_names);
2499 kfree_const(clk->name);
2503 return ERR_PTR(ret);
2505 EXPORT_SYMBOL_GPL(clk_register);
2508 * Free memory allocated for a clock.
2509 * Caller must hold prepare_lock.
2511 static void __clk_release(struct kref *ref)
2513 struct clk_core *clk = container_of(ref, struct clk_core, ref);
2514 int i = clk->num_parents;
2516 kfree(clk->parents);
2518 kfree_const(clk->parent_names[i]);
2520 kfree(clk->parent_names);
2521 kfree_const(clk->name);
2526 * Empty clk_ops for unregistered clocks. These are used temporarily
2527 * after clk_unregister() was called on a clock and until last clock
2528 * consumer calls clk_put() and the struct clk object is freed.
2530 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2535 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2540 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2541 unsigned long parent_rate)
2546 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2551 static const struct clk_ops clk_nodrv_ops = {
2552 .enable = clk_nodrv_prepare_enable,
2553 .disable = clk_nodrv_disable_unprepare,
2554 .prepare = clk_nodrv_prepare_enable,
2555 .unprepare = clk_nodrv_disable_unprepare,
2556 .set_rate = clk_nodrv_set_rate,
2557 .set_parent = clk_nodrv_set_parent,
2561 * clk_unregister - unregister a currently registered clock
2562 * @clk: clock to unregister
2564 void clk_unregister(struct clk *clk)
2566 unsigned long flags;
2568 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2571 clk_debug_unregister(clk->core);
2575 if (clk->core->ops == &clk_nodrv_ops) {
2576 pr_err("%s: unregistered clock: %s\n", __func__,
2581 * Assign empty clock ops for consumers that might still hold
2582 * a reference to this clock.
2584 flags = clk_enable_lock();
2585 clk->core->ops = &clk_nodrv_ops;
2586 clk_enable_unlock(flags);
2588 if (!hlist_empty(&clk->core->children)) {
2589 struct clk_core *child;
2590 struct hlist_node *t;
2592 /* Reparent all children to the orphan list. */
2593 hlist_for_each_entry_safe(child, t, &clk->core->children,
2595 clk_core_set_parent(child, NULL);
2598 hlist_del_init(&clk->core->child_node);
2600 if (clk->core->prepare_count)
2601 pr_warn("%s: unregistering prepared clock: %s\n",
2602 __func__, clk->core->name);
2603 kref_put(&clk->core->ref, __clk_release);
2605 clk_prepare_unlock();
2607 EXPORT_SYMBOL_GPL(clk_unregister);
2609 static void devm_clk_release(struct device *dev, void *res)
2611 clk_unregister(*(struct clk **)res);
2615 * devm_clk_register - resource managed clk_register()
2616 * @dev: device that is registering this clock
2617 * @hw: link to hardware-specific clock data
2619 * Managed clk_register(). Clocks returned from this function are
2620 * automatically clk_unregister()ed on driver detach. See clk_register() for
2623 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2628 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2630 return ERR_PTR(-ENOMEM);
2632 clk = clk_register(dev, hw);
2635 devres_add(dev, clkp);
2642 EXPORT_SYMBOL_GPL(devm_clk_register);
2644 static int devm_clk_match(struct device *dev, void *res, void *data)
2646 struct clk *c = res;
2653 * devm_clk_unregister - resource managed clk_unregister()
2654 * @clk: clock to unregister
2656 * Deallocate a clock allocated with devm_clk_register(). Normally
2657 * this function will not need to be called and the resource management
2658 * code will ensure that the resource is freed.
2660 void devm_clk_unregister(struct device *dev, struct clk *clk)
2662 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2664 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2669 int __clk_get(struct clk *clk)
2671 struct clk_core *core = !clk ? NULL : clk->core;
2674 if (!try_module_get(core->owner))
2677 kref_get(&core->ref);
2682 void __clk_put(struct clk *clk)
2684 struct module *owner;
2686 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2691 hlist_del(&clk->child_node);
2692 if (clk->min_rate > clk->core->req_rate ||
2693 clk->max_rate < clk->core->req_rate)
2694 clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
2696 owner = clk->core->owner;
2697 kref_put(&clk->core->ref, __clk_release);
2699 clk_prepare_unlock();
2706 /*** clk rate change notifiers ***/
2709 * clk_notifier_register - add a clk rate change notifier
2710 * @clk: struct clk * to watch
2711 * @nb: struct notifier_block * with callback info
2713 * Request notification when clk's rate changes. This uses an SRCU
2714 * notifier because we want it to block and notifier unregistrations are
2715 * uncommon. The callbacks associated with the notifier must not
2716 * re-enter into the clk framework by calling any top-level clk APIs;
2717 * this will cause a nested prepare_lock mutex.
2719 * In all notification cases cases (pre, post and abort rate change) the
2720 * original clock rate is passed to the callback via struct
2721 * clk_notifier_data.old_rate and the new frequency is passed via struct
2722 * clk_notifier_data.new_rate.
2724 * clk_notifier_register() must be called from non-atomic context.
2725 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2726 * allocation failure; otherwise, passes along the return value of
2727 * srcu_notifier_chain_register().
2729 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2731 struct clk_notifier *cn;
2739 /* search the list of notifiers for this clk */
2740 list_for_each_entry(cn, &clk_notifier_list, node)
2744 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2745 if (cn->clk != clk) {
2746 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2751 srcu_init_notifier_head(&cn->notifier_head);
2753 list_add(&cn->node, &clk_notifier_list);
2756 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2758 clk->core->notifier_count++;
2761 clk_prepare_unlock();
2765 EXPORT_SYMBOL_GPL(clk_notifier_register);
2768 * clk_notifier_unregister - remove a clk rate change notifier
2769 * @clk: struct clk *
2770 * @nb: struct notifier_block * with callback info
2772 * Request no further notification for changes to 'clk' and frees memory
2773 * allocated in clk_notifier_register.
2775 * Returns -EINVAL if called with null arguments; otherwise, passes
2776 * along the return value of srcu_notifier_chain_unregister().
2778 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2780 struct clk_notifier *cn = NULL;
2788 list_for_each_entry(cn, &clk_notifier_list, node)
2792 if (cn->clk == clk) {
2793 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2795 clk->core->notifier_count--;
2797 /* XXX the notifier code should handle this better */
2798 if (!cn->notifier_head.head) {
2799 srcu_cleanup_notifier_head(&cn->notifier_head);
2800 list_del(&cn->node);
2808 clk_prepare_unlock();
2812 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2816 * struct of_clk_provider - Clock provider registration structure
2817 * @link: Entry in global list of clock providers
2818 * @node: Pointer to device tree node of clock provider
2819 * @get: Get clock callback. Returns NULL or a struct clk for the
2820 * given clock specifier
2821 * @data: context pointer to be passed into @get callback
2823 struct of_clk_provider {
2824 struct list_head link;
2826 struct device_node *node;
2827 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2831 static const struct of_device_id __clk_of_table_sentinel
2832 __used __section(__clk_of_table_end);
2834 static LIST_HEAD(of_clk_providers);
2835 static DEFINE_MUTEX(of_clk_mutex);
2837 /* of_clk_provider list locking helpers */
2838 void of_clk_lock(void)
2840 mutex_lock(&of_clk_mutex);
2843 void of_clk_unlock(void)
2845 mutex_unlock(&of_clk_mutex);
2848 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2853 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2855 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2857 struct clk_onecell_data *clk_data = data;
2858 unsigned int idx = clkspec->args[0];
2860 if (idx >= clk_data->clk_num) {
2861 pr_err("%s: invalid clock index %d\n", __func__, idx);
2862 return ERR_PTR(-EINVAL);
2865 return clk_data->clks[idx];
2867 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2870 * of_clk_add_provider() - Register a clock provider for a node
2871 * @np: Device node pointer associated with clock provider
2872 * @clk_src_get: callback for decoding clock
2873 * @data: context pointer for @clk_src_get callback.
2875 int of_clk_add_provider(struct device_node *np,
2876 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2880 struct of_clk_provider *cp;
2883 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2887 cp->node = of_node_get(np);
2889 cp->get = clk_src_get;
2891 mutex_lock(&of_clk_mutex);
2892 list_add(&cp->link, &of_clk_providers);
2893 mutex_unlock(&of_clk_mutex);
2894 pr_debug("Added clock from %s\n", np->full_name);
2896 ret = of_clk_set_defaults(np, true);
2898 of_clk_del_provider(np);
2902 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2905 * of_clk_del_provider() - Remove a previously registered clock provider
2906 * @np: Device node pointer associated with clock provider
2908 void of_clk_del_provider(struct device_node *np)
2910 struct of_clk_provider *cp;
2912 mutex_lock(&of_clk_mutex);
2913 list_for_each_entry(cp, &of_clk_providers, link) {
2914 if (cp->node == np) {
2915 list_del(&cp->link);
2916 of_node_put(cp->node);
2921 mutex_unlock(&of_clk_mutex);
2923 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2925 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
2926 const char *dev_id, const char *con_id)
2928 struct of_clk_provider *provider;
2929 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2931 /* Check if we have such a provider in our array */
2932 list_for_each_entry(provider, &of_clk_providers, link) {
2933 if (provider->node == clkspec->np)
2934 clk = provider->get(clkspec, provider->data);
2936 clk = __clk_create_clk(__clk_get_hw(clk), dev_id,
2939 if (!IS_ERR(clk) && !__clk_get(clk)) {
2940 __clk_free_clk(clk);
2941 clk = ERR_PTR(-ENOENT);
2951 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2955 mutex_lock(&of_clk_mutex);
2956 clk = __of_clk_get_from_provider(clkspec, NULL, __func__);
2957 mutex_unlock(&of_clk_mutex);
2962 int of_clk_get_parent_count(struct device_node *np)
2964 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2966 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2968 const char *of_clk_get_parent_name(struct device_node *np, int index)
2970 struct of_phandle_args clkspec;
2971 struct property *prop;
2972 const char *clk_name;
2981 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2986 index = clkspec.args_count ? clkspec.args[0] : 0;
2989 /* if there is an indices property, use it to transfer the index
2990 * specified into an array offset for the clock-output-names property.
2992 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
3000 if (of_property_read_string_index(clkspec.np, "clock-output-names",
3003 clk_name = clkspec.np->name;
3005 of_node_put(clkspec.np);
3008 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
3010 struct clock_provider {
3011 of_clk_init_cb_t clk_init_cb;
3012 struct device_node *np;
3013 struct list_head node;
3016 static LIST_HEAD(clk_provider_list);
3019 * This function looks for a parent clock. If there is one, then it
3020 * checks that the provider for this parent clock was initialized, in
3021 * this case the parent clock will be ready.
3023 static int parent_ready(struct device_node *np)
3028 struct clk *clk = of_clk_get(np, i);
3030 /* this parent is ready we can check the next one */
3037 /* at least one parent is not ready, we exit now */
3038 if (PTR_ERR(clk) == -EPROBE_DEFER)
3042 * Here we make assumption that the device tree is
3043 * written correctly. So an error means that there is
3044 * no more parent. As we didn't exit yet, then the
3045 * previous parent are ready. If there is no clock
3046 * parent, no need to wait for them, then we can
3047 * consider their absence as being ready
3054 * of_clk_init() - Scan and init clock providers from the DT
3055 * @matches: array of compatible values and init functions for providers.
3057 * This function scans the device tree for matching clock providers
3058 * and calls their initialization functions. It also does it by trying
3059 * to follow the dependencies.
3061 void __init of_clk_init(const struct of_device_id *matches)
3063 const struct of_device_id *match;
3064 struct device_node *np;
3065 struct clock_provider *clk_provider, *next;
3070 matches = &__clk_of_table;
3072 /* First prepare the list of the clocks providers */
3073 for_each_matching_node_and_match(np, matches, &match) {
3074 struct clock_provider *parent =
3075 kzalloc(sizeof(struct clock_provider), GFP_KERNEL);
3077 parent->clk_init_cb = match->data;
3079 list_add_tail(&parent->node, &clk_provider_list);
3082 while (!list_empty(&clk_provider_list)) {
3083 is_init_done = false;
3084 list_for_each_entry_safe(clk_provider, next,
3085 &clk_provider_list, node) {
3086 if (force || parent_ready(clk_provider->np)) {
3088 clk_provider->clk_init_cb(clk_provider->np);
3089 of_clk_set_defaults(clk_provider->np, true);
3091 list_del(&clk_provider->node);
3092 kfree(clk_provider);
3093 is_init_done = true;
3098 * We didn't manage to initialize any of the
3099 * remaining providers during the last loop, so now we
3100 * initialize all the remaining ones unconditionally
3101 * in case the clock parent was not mandatory