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 clks_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, clks_node)
866 *min_rate = max(*min_rate, clk_user->min_rate);
868 hlist_for_each_entry(clk_user, &clk->clks, clks_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();
1387 * clk_get_rate - return the rate of clk
1388 * @clk: the clk whose rate is being returned
1390 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1391 * is set, which means a recalc_rate will be issued.
1392 * If clk is NULL then returns 0.
1394 unsigned long clk_get_rate(struct clk *clk)
1399 return clk_core_get_rate(clk->core);
1401 EXPORT_SYMBOL_GPL(clk_get_rate);
1403 static int clk_fetch_parent_index(struct clk_core *clk,
1404 struct clk_core *parent)
1408 if (!clk->parents) {
1409 clk->parents = kcalloc(clk->num_parents,
1410 sizeof(struct clk *), GFP_KERNEL);
1416 * find index of new parent clock using cached parent ptrs,
1417 * or if not yet cached, use string name comparison and cache
1418 * them now to avoid future calls to clk_core_lookup.
1420 for (i = 0; i < clk->num_parents; i++) {
1421 if (clk->parents[i] == parent)
1424 if (clk->parents[i])
1427 if (!strcmp(clk->parent_names[i], parent->name)) {
1428 clk->parents[i] = clk_core_lookup(parent->name);
1436 static void clk_reparent(struct clk_core *clk, struct clk_core *new_parent)
1438 hlist_del(&clk->child_node);
1441 /* avoid duplicate POST_RATE_CHANGE notifications */
1442 if (new_parent->new_child == clk)
1443 new_parent->new_child = NULL;
1445 hlist_add_head(&clk->child_node, &new_parent->children);
1447 hlist_add_head(&clk->child_node, &clk_orphan_list);
1450 clk->parent = new_parent;
1453 static struct clk_core *__clk_set_parent_before(struct clk_core *clk,
1454 struct clk_core *parent)
1456 unsigned long flags;
1457 struct clk_core *old_parent = clk->parent;
1460 * Migrate prepare state between parents and prevent race with
1463 * If the clock is not prepared, then a race with
1464 * clk_enable/disable() is impossible since we already have the
1465 * prepare lock (future calls to clk_enable() need to be preceded by
1468 * If the clock is prepared, migrate the prepared state to the new
1469 * parent and also protect against a race with clk_enable() by
1470 * forcing the clock and the new parent on. This ensures that all
1471 * future calls to clk_enable() are practically NOPs with respect to
1472 * hardware and software states.
1474 * See also: Comment for clk_set_parent() below.
1476 if (clk->prepare_count) {
1477 clk_core_prepare(parent);
1478 clk_core_enable(parent);
1479 clk_core_enable(clk);
1482 /* update the clk tree topology */
1483 flags = clk_enable_lock();
1484 clk_reparent(clk, parent);
1485 clk_enable_unlock(flags);
1490 static void __clk_set_parent_after(struct clk_core *core,
1491 struct clk_core *parent,
1492 struct clk_core *old_parent)
1495 * Finish the migration of prepare state and undo the changes done
1496 * for preventing a race with clk_enable().
1498 if (core->prepare_count) {
1499 clk_core_disable(core);
1500 clk_core_disable(old_parent);
1501 clk_core_unprepare(old_parent);
1505 static int __clk_set_parent(struct clk_core *clk, struct clk_core *parent,
1508 unsigned long flags;
1510 struct clk_core *old_parent;
1512 old_parent = __clk_set_parent_before(clk, parent);
1514 trace_clk_set_parent(clk, parent);
1516 /* change clock input source */
1517 if (parent && clk->ops->set_parent)
1518 ret = clk->ops->set_parent(clk->hw, p_index);
1520 trace_clk_set_parent_complete(clk, parent);
1523 flags = clk_enable_lock();
1524 clk_reparent(clk, old_parent);
1525 clk_enable_unlock(flags);
1527 if (clk->prepare_count) {
1528 clk_core_disable(clk);
1529 clk_core_disable(parent);
1530 clk_core_unprepare(parent);
1535 __clk_set_parent_after(clk, parent, old_parent);
1541 * __clk_speculate_rates
1542 * @clk: first clk in the subtree
1543 * @parent_rate: the "future" rate of clk's parent
1545 * Walks the subtree of clks starting with clk, speculating rates as it
1546 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1548 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1549 * pre-rate change notifications and returns early if no clks in the
1550 * subtree have subscribed to the notifications. Note that if a clk does not
1551 * implement the .recalc_rate callback then it is assumed that the clock will
1552 * take on the rate of its parent.
1554 * Caller must hold prepare_lock.
1556 static int __clk_speculate_rates(struct clk_core *clk,
1557 unsigned long parent_rate)
1559 struct clk_core *child;
1560 unsigned long new_rate;
1561 int ret = NOTIFY_DONE;
1563 lockdep_assert_held(&prepare_lock);
1565 new_rate = clk_recalc(clk, parent_rate);
1567 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1568 if (clk->notifier_count)
1569 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1571 if (ret & NOTIFY_STOP_MASK) {
1572 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1573 __func__, clk->name, ret);
1577 hlist_for_each_entry(child, &clk->children, child_node) {
1578 ret = __clk_speculate_rates(child, new_rate);
1579 if (ret & NOTIFY_STOP_MASK)
1587 static void clk_calc_subtree(struct clk_core *clk, unsigned long new_rate,
1588 struct clk_core *new_parent, u8 p_index)
1590 struct clk_core *child;
1592 clk->new_rate = new_rate;
1593 clk->new_parent = new_parent;
1594 clk->new_parent_index = p_index;
1595 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1596 clk->new_child = NULL;
1597 if (new_parent && new_parent != clk->parent)
1598 new_parent->new_child = clk;
1600 hlist_for_each_entry(child, &clk->children, child_node) {
1601 child->new_rate = clk_recalc(child, new_rate);
1602 clk_calc_subtree(child, child->new_rate, NULL, 0);
1607 * calculate the new rates returning the topmost clock that has to be
1610 static struct clk_core *clk_calc_new_rates(struct clk_core *clk,
1613 struct clk_core *top = clk;
1614 struct clk_core *old_parent, *parent;
1615 struct clk_hw *parent_hw;
1616 unsigned long best_parent_rate = 0;
1617 unsigned long new_rate;
1618 unsigned long min_rate;
1619 unsigned long max_rate;
1623 if (IS_ERR_OR_NULL(clk))
1626 /* save parent rate, if it exists */
1627 parent = old_parent = clk->parent;
1629 best_parent_rate = parent->rate;
1631 clk_core_get_boundaries(clk, &min_rate, &max_rate);
1633 /* find the closest rate and parent clk/rate */
1634 if (clk->ops->determine_rate) {
1635 parent_hw = parent ? parent->hw : NULL;
1636 new_rate = clk->ops->determine_rate(clk->hw, rate,
1641 parent = parent_hw ? parent_hw->core : NULL;
1642 } else if (clk->ops->round_rate) {
1643 new_rate = clk->ops->round_rate(clk->hw, rate,
1645 if (new_rate < min_rate || new_rate > max_rate)
1647 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1648 /* pass-through clock without adjustable parent */
1649 clk->new_rate = clk->rate;
1652 /* pass-through clock with adjustable parent */
1653 top = clk_calc_new_rates(parent, rate);
1654 new_rate = parent->new_rate;
1658 /* some clocks must be gated to change parent */
1659 if (parent != old_parent &&
1660 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1661 pr_debug("%s: %s not gated but wants to reparent\n",
1662 __func__, clk->name);
1666 /* try finding the new parent index */
1667 if (parent && clk->num_parents > 1) {
1668 p_index = clk_fetch_parent_index(clk, parent);
1670 pr_debug("%s: clk %s can not be parent of clk %s\n",
1671 __func__, parent->name, clk->name);
1676 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1677 best_parent_rate != parent->rate)
1678 top = clk_calc_new_rates(parent, best_parent_rate);
1681 clk_calc_subtree(clk, new_rate, parent, p_index);
1687 * Notify about rate changes in a subtree. Always walk down the whole tree
1688 * so that in case of an error we can walk down the whole tree again and
1691 static struct clk_core *clk_propagate_rate_change(struct clk_core *clk,
1692 unsigned long event)
1694 struct clk_core *child, *tmp_clk, *fail_clk = NULL;
1695 int ret = NOTIFY_DONE;
1697 if (clk->rate == clk->new_rate)
1700 if (clk->notifier_count) {
1701 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1702 if (ret & NOTIFY_STOP_MASK)
1706 hlist_for_each_entry(child, &clk->children, child_node) {
1707 /* Skip children who will be reparented to another clock */
1708 if (child->new_parent && child->new_parent != clk)
1710 tmp_clk = clk_propagate_rate_change(child, event);
1715 /* handle the new child who might not be in clk->children yet */
1716 if (clk->new_child) {
1717 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1726 * walk down a subtree and set the new rates notifying the rate
1729 static void clk_change_rate(struct clk_core *clk)
1731 struct clk_core *child;
1732 struct hlist_node *tmp;
1733 unsigned long old_rate;
1734 unsigned long best_parent_rate = 0;
1735 bool skip_set_rate = false;
1736 struct clk_core *old_parent;
1738 old_rate = clk->rate;
1740 if (clk->new_parent)
1741 best_parent_rate = clk->new_parent->rate;
1742 else if (clk->parent)
1743 best_parent_rate = clk->parent->rate;
1745 if (clk->new_parent && clk->new_parent != clk->parent) {
1746 old_parent = __clk_set_parent_before(clk, clk->new_parent);
1747 trace_clk_set_parent(clk, clk->new_parent);
1749 if (clk->ops->set_rate_and_parent) {
1750 skip_set_rate = true;
1751 clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
1753 clk->new_parent_index);
1754 } else if (clk->ops->set_parent) {
1755 clk->ops->set_parent(clk->hw, clk->new_parent_index);
1758 trace_clk_set_parent_complete(clk, clk->new_parent);
1759 __clk_set_parent_after(clk, clk->new_parent, old_parent);
1762 trace_clk_set_rate(clk, clk->new_rate);
1764 if (!skip_set_rate && clk->ops->set_rate)
1765 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1767 trace_clk_set_rate_complete(clk, clk->new_rate);
1769 clk->rate = clk_recalc(clk, best_parent_rate);
1771 if (clk->notifier_count && old_rate != clk->rate)
1772 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1775 * Use safe iteration, as change_rate can actually swap parents
1776 * for certain clock types.
1778 hlist_for_each_entry_safe(child, tmp, &clk->children, child_node) {
1779 /* Skip children who will be reparented to another clock */
1780 if (child->new_parent && child->new_parent != clk)
1782 clk_change_rate(child);
1785 /* handle the new child who might not be in clk->children yet */
1787 clk_change_rate(clk->new_child);
1790 static int clk_core_set_rate_nolock(struct clk_core *clk,
1791 unsigned long req_rate)
1793 struct clk_core *top, *fail_clk;
1794 unsigned long rate = req_rate;
1800 /* bail early if nothing to do */
1801 if (rate == clk_core_get_rate_nolock(clk))
1804 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count)
1807 /* calculate new rates and get the topmost changed clock */
1808 top = clk_calc_new_rates(clk, rate);
1812 /* notify that we are about to change rates */
1813 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1815 pr_debug("%s: failed to set %s rate\n", __func__,
1817 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1821 /* change the rates */
1822 clk_change_rate(top);
1824 clk->req_rate = req_rate;
1830 * clk_set_rate - specify a new rate for clk
1831 * @clk: the clk whose rate is being changed
1832 * @rate: the new rate for clk
1834 * In the simplest case clk_set_rate will only adjust the rate of clk.
1836 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1837 * propagate up to clk's parent; whether or not this happens depends on the
1838 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1839 * after calling .round_rate then upstream parent propagation is ignored. If
1840 * *parent_rate comes back with a new rate for clk's parent then we propagate
1841 * up to clk's parent and set its rate. Upward propagation will continue
1842 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1843 * .round_rate stops requesting changes to clk's parent_rate.
1845 * Rate changes are accomplished via tree traversal that also recalculates the
1846 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1848 * Returns 0 on success, -EERROR otherwise.
1850 int clk_set_rate(struct clk *clk, unsigned long rate)
1857 /* prevent racing with updates to the clock topology */
1860 ret = clk_core_set_rate_nolock(clk->core, rate);
1862 clk_prepare_unlock();
1866 EXPORT_SYMBOL_GPL(clk_set_rate);
1869 * clk_set_rate_range - set a rate range for a clock source
1870 * @clk: clock source
1871 * @min: desired minimum clock rate in Hz, inclusive
1872 * @max: desired maximum clock rate in Hz, inclusive
1874 * Returns success (0) or negative errno.
1876 int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
1884 pr_err("%s: clk %s dev %s con %s: invalid range [%lu, %lu]\n",
1885 __func__, clk->core->name, clk->dev_id, clk->con_id,
1892 if (min != clk->min_rate || max != clk->max_rate) {
1893 clk->min_rate = min;
1894 clk->max_rate = max;
1895 ret = clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
1898 clk_prepare_unlock();
1902 EXPORT_SYMBOL_GPL(clk_set_rate_range);
1905 * clk_set_min_rate - set a minimum clock rate for a clock source
1906 * @clk: clock source
1907 * @rate: desired minimum clock rate in Hz, inclusive
1909 * Returns success (0) or negative errno.
1911 int clk_set_min_rate(struct clk *clk, unsigned long rate)
1916 return clk_set_rate_range(clk, rate, clk->max_rate);
1918 EXPORT_SYMBOL_GPL(clk_set_min_rate);
1921 * clk_set_max_rate - set a maximum clock rate for a clock source
1922 * @clk: clock source
1923 * @rate: desired maximum clock rate in Hz, inclusive
1925 * Returns success (0) or negative errno.
1927 int clk_set_max_rate(struct clk *clk, unsigned long rate)
1932 return clk_set_rate_range(clk, clk->min_rate, rate);
1934 EXPORT_SYMBOL_GPL(clk_set_max_rate);
1937 * clk_get_parent - return the parent of a clk
1938 * @clk: the clk whose parent gets returned
1940 * Simply returns clk->parent. Returns NULL if clk is NULL.
1942 struct clk *clk_get_parent(struct clk *clk)
1947 parent = __clk_get_parent(clk);
1948 clk_prepare_unlock();
1952 EXPORT_SYMBOL_GPL(clk_get_parent);
1955 * .get_parent is mandatory for clocks with multiple possible parents. It is
1956 * optional for single-parent clocks. Always call .get_parent if it is
1957 * available and WARN if it is missing for multi-parent clocks.
1959 * For single-parent clocks without .get_parent, first check to see if the
1960 * .parents array exists, and if so use it to avoid an expensive tree
1961 * traversal. If .parents does not exist then walk the tree.
1963 static struct clk_core *__clk_init_parent(struct clk_core *clk)
1965 struct clk_core *ret = NULL;
1968 /* handle the trivial cases */
1970 if (!clk->num_parents)
1973 if (clk->num_parents == 1) {
1974 if (IS_ERR_OR_NULL(clk->parent))
1975 clk->parent = clk_core_lookup(clk->parent_names[0]);
1980 if (!clk->ops->get_parent) {
1981 WARN(!clk->ops->get_parent,
1982 "%s: multi-parent clocks must implement .get_parent\n",
1988 * Do our best to cache parent clocks in clk->parents. This prevents
1989 * unnecessary and expensive lookups. We don't set clk->parent here;
1990 * that is done by the calling function.
1993 index = clk->ops->get_parent(clk->hw);
1997 kcalloc(clk->num_parents, sizeof(struct clk *),
2000 ret = clk_core_get_parent_by_index(clk, index);
2006 static void clk_core_reparent(struct clk_core *clk,
2007 struct clk_core *new_parent)
2009 clk_reparent(clk, new_parent);
2010 __clk_recalc_accuracies(clk);
2011 __clk_recalc_rates(clk, POST_RATE_CHANGE);
2014 void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent)
2019 clk_core_reparent(hw->core, !new_parent ? NULL : new_parent->core);
2023 * clk_has_parent - check if a clock is a possible parent for another
2024 * @clk: clock source
2025 * @parent: parent clock source
2027 * This function can be used in drivers that need to check that a clock can be
2028 * the parent of another without actually changing the parent.
2030 * Returns true if @parent is a possible parent for @clk, false otherwise.
2032 bool clk_has_parent(struct clk *clk, struct clk *parent)
2034 struct clk_core *core, *parent_core;
2037 /* NULL clocks should be nops, so return success if either is NULL. */
2038 if (!clk || !parent)
2042 parent_core = parent->core;
2044 /* Optimize for the case where the parent is already the parent. */
2045 if (core->parent == parent_core)
2048 for (i = 0; i < core->num_parents; i++)
2049 if (strcmp(core->parent_names[i], parent_core->name) == 0)
2054 EXPORT_SYMBOL_GPL(clk_has_parent);
2056 static int clk_core_set_parent(struct clk_core *clk, struct clk_core *parent)
2060 unsigned long p_rate = 0;
2065 /* prevent racing with updates to the clock topology */
2068 if (clk->parent == parent)
2071 /* verify ops for for multi-parent clks */
2072 if ((clk->num_parents > 1) && (!clk->ops->set_parent)) {
2077 /* check that we are allowed to re-parent if the clock is in use */
2078 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
2083 /* try finding the new parent index */
2085 p_index = clk_fetch_parent_index(clk, parent);
2086 p_rate = parent->rate;
2088 pr_debug("%s: clk %s can not be parent of clk %s\n",
2089 __func__, parent->name, clk->name);
2095 /* propagate PRE_RATE_CHANGE notifications */
2096 ret = __clk_speculate_rates(clk, p_rate);
2098 /* abort if a driver objects */
2099 if (ret & NOTIFY_STOP_MASK)
2102 /* do the re-parent */
2103 ret = __clk_set_parent(clk, parent, p_index);
2105 /* propagate rate an accuracy recalculation accordingly */
2107 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
2109 __clk_recalc_rates(clk, POST_RATE_CHANGE);
2110 __clk_recalc_accuracies(clk);
2114 clk_prepare_unlock();
2120 * clk_set_parent - switch the parent of a mux clk
2121 * @clk: the mux clk whose input we are switching
2122 * @parent: the new input to clk
2124 * Re-parent clk to use parent as its new input source. If clk is in
2125 * prepared state, the clk will get enabled for the duration of this call. If
2126 * that's not acceptable for a specific clk (Eg: the consumer can't handle
2127 * that, the reparenting is glitchy in hardware, etc), use the
2128 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
2130 * After successfully changing clk's parent clk_set_parent will update the
2131 * clk topology, sysfs topology and propagate rate recalculation via
2132 * __clk_recalc_rates.
2134 * Returns 0 on success, -EERROR otherwise.
2136 int clk_set_parent(struct clk *clk, struct clk *parent)
2141 return clk_core_set_parent(clk->core, parent ? parent->core : NULL);
2143 EXPORT_SYMBOL_GPL(clk_set_parent);
2146 * clk_set_phase - adjust the phase shift of a clock signal
2147 * @clk: clock signal source
2148 * @degrees: number of degrees the signal is shifted
2150 * Shifts the phase of a clock signal by the specified
2151 * degrees. Returns 0 on success, -EERROR otherwise.
2153 * This function makes no distinction about the input or reference
2154 * signal that we adjust the clock signal phase against. For example
2155 * phase locked-loop clock signal generators we may shift phase with
2156 * respect to feedback clock signal input, but for other cases the
2157 * clock phase may be shifted with respect to some other, unspecified
2160 * Additionally the concept of phase shift does not propagate through
2161 * the clock tree hierarchy, which sets it apart from clock rates and
2162 * clock accuracy. A parent clock phase attribute does not have an
2163 * impact on the phase attribute of a child clock.
2165 int clk_set_phase(struct clk *clk, int degrees)
2172 /* sanity check degrees */
2179 trace_clk_set_phase(clk->core, degrees);
2181 if (clk->core->ops->set_phase)
2182 ret = clk->core->ops->set_phase(clk->core->hw, degrees);
2184 trace_clk_set_phase_complete(clk->core, degrees);
2187 clk->core->phase = degrees;
2189 clk_prepare_unlock();
2193 EXPORT_SYMBOL_GPL(clk_set_phase);
2195 static int clk_core_get_phase(struct clk_core *clk)
2204 clk_prepare_unlock();
2209 EXPORT_SYMBOL_GPL(clk_get_phase);
2212 * clk_get_phase - return the phase shift of a clock signal
2213 * @clk: clock signal source
2215 * Returns the phase shift of a clock node in degrees, otherwise returns
2218 int clk_get_phase(struct clk *clk)
2223 return clk_core_get_phase(clk->core);
2227 * clk_is_match - check if two clk's point to the same hardware clock
2228 * @p: clk compared against q
2229 * @q: clk compared against p
2231 * Returns true if the two struct clk pointers both point to the same hardware
2232 * clock node. Put differently, returns true if struct clk *p and struct clk *q
2233 * share the same struct clk_core object.
2235 * Returns false otherwise. Note that two NULL clks are treated as matching.
2237 bool clk_is_match(const struct clk *p, const struct clk *q)
2239 /* trivial case: identical struct clk's or both NULL */
2243 /* true if clk->core pointers match. Avoid derefing garbage */
2244 if (!IS_ERR_OR_NULL(p) && !IS_ERR_OR_NULL(q))
2245 if (p->core == q->core)
2250 EXPORT_SYMBOL_GPL(clk_is_match);
2253 * __clk_init - initialize the data structures in a struct clk
2254 * @dev: device initializing this clk, placeholder for now
2255 * @clk: clk being initialized
2257 * Initializes the lists in struct clk_core, queries the hardware for the
2258 * parent and rate and sets them both.
2260 static int __clk_init(struct device *dev, struct clk *clk_user)
2263 struct clk_core *orphan;
2264 struct hlist_node *tmp2;
2265 struct clk_core *clk;
2271 clk = clk_user->core;
2275 /* check to see if a clock with this name is already registered */
2276 if (clk_core_lookup(clk->name)) {
2277 pr_debug("%s: clk %s already initialized\n",
2278 __func__, clk->name);
2283 /* check that clk_ops are sane. See Documentation/clk.txt */
2284 if (clk->ops->set_rate &&
2285 !((clk->ops->round_rate || clk->ops->determine_rate) &&
2286 clk->ops->recalc_rate)) {
2287 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
2288 __func__, clk->name);
2293 if (clk->ops->set_parent && !clk->ops->get_parent) {
2294 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
2295 __func__, clk->name);
2300 if (clk->ops->set_rate_and_parent &&
2301 !(clk->ops->set_parent && clk->ops->set_rate)) {
2302 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
2303 __func__, clk->name);
2308 /* throw a WARN if any entries in parent_names are NULL */
2309 for (i = 0; i < clk->num_parents; i++)
2310 WARN(!clk->parent_names[i],
2311 "%s: invalid NULL in %s's .parent_names\n",
2312 __func__, clk->name);
2315 * Allocate an array of struct clk *'s to avoid unnecessary string
2316 * look-ups of clk's possible parents. This can fail for clocks passed
2317 * in to clk_init during early boot; thus any access to clk->parents[]
2318 * must always check for a NULL pointer and try to populate it if
2321 * If clk->parents is not NULL we skip this entire block. This allows
2322 * for clock drivers to statically initialize clk->parents.
2324 if (clk->num_parents > 1 && !clk->parents) {
2325 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
2328 * clk_core_lookup returns NULL for parents that have not been
2329 * clk_init'd; thus any access to clk->parents[] must check
2330 * for a NULL pointer. We can always perform lazy lookups for
2331 * missing parents later on.
2334 for (i = 0; i < clk->num_parents; i++)
2336 clk_core_lookup(clk->parent_names[i]);
2339 clk->parent = __clk_init_parent(clk);
2342 * Populate clk->parent if parent has already been __clk_init'd. If
2343 * parent has not yet been __clk_init'd then place clk in the orphan
2344 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
2347 * Every time a new clk is clk_init'd then we walk the list of orphan
2348 * clocks and re-parent any that are children of the clock currently
2352 hlist_add_head(&clk->child_node,
2353 &clk->parent->children);
2354 else if (clk->flags & CLK_IS_ROOT)
2355 hlist_add_head(&clk->child_node, &clk_root_list);
2357 hlist_add_head(&clk->child_node, &clk_orphan_list);
2360 * Set clk's accuracy. The preferred method is to use
2361 * .recalc_accuracy. For simple clocks and lazy developers the default
2362 * fallback is to use the parent's accuracy. If a clock doesn't have a
2363 * parent (or is orphaned) then accuracy is set to zero (perfect
2366 if (clk->ops->recalc_accuracy)
2367 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
2368 __clk_get_accuracy(clk->parent));
2369 else if (clk->parent)
2370 clk->accuracy = clk->parent->accuracy;
2376 * Since a phase is by definition relative to its parent, just
2377 * query the current clock phase, or just assume it's in phase.
2379 if (clk->ops->get_phase)
2380 clk->phase = clk->ops->get_phase(clk->hw);
2385 * Set clk's rate. The preferred method is to use .recalc_rate. For
2386 * simple clocks and lazy developers the default fallback is to use the
2387 * parent's rate. If a clock doesn't have a parent (or is orphaned)
2388 * then rate is set to zero.
2390 if (clk->ops->recalc_rate)
2391 rate = clk->ops->recalc_rate(clk->hw,
2392 clk_core_get_rate_nolock(clk->parent));
2393 else if (clk->parent)
2394 rate = clk->parent->rate;
2397 clk->rate = clk->req_rate = rate;
2400 * walk the list of orphan clocks and reparent any that are children of
2403 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
2404 if (orphan->num_parents && orphan->ops->get_parent) {
2405 i = orphan->ops->get_parent(orphan->hw);
2406 if (!strcmp(clk->name, orphan->parent_names[i]))
2407 clk_core_reparent(orphan, clk);
2411 for (i = 0; i < orphan->num_parents; i++)
2412 if (!strcmp(clk->name, orphan->parent_names[i])) {
2413 clk_core_reparent(orphan, clk);
2419 * optional platform-specific magic
2421 * The .init callback is not used by any of the basic clock types, but
2422 * exists for weird hardware that must perform initialization magic.
2423 * Please consider other ways of solving initialization problems before
2424 * using this callback, as its use is discouraged.
2427 clk->ops->init(clk->hw);
2429 kref_init(&clk->ref);
2431 clk_prepare_unlock();
2434 clk_debug_register(clk);
2439 struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
2444 /* This is to allow this function to be chained to others */
2445 if (!hw || IS_ERR(hw))
2446 return (struct clk *) hw;
2448 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2450 return ERR_PTR(-ENOMEM);
2452 clk->core = hw->core;
2453 clk->dev_id = dev_id;
2454 clk->con_id = con_id;
2455 clk->max_rate = ULONG_MAX;
2458 hlist_add_head(&clk->clks_node, &hw->core->clks);
2459 clk_prepare_unlock();
2464 void __clk_free_clk(struct clk *clk)
2467 hlist_del(&clk->clks_node);
2468 clk_prepare_unlock();
2474 * clk_register - allocate a new clock, register it and return an opaque cookie
2475 * @dev: device that is registering this clock
2476 * @hw: link to hardware-specific clock data
2478 * clk_register is the primary interface for populating the clock tree with new
2479 * clock nodes. It returns a pointer to the newly allocated struct clk which
2480 * cannot be dereferenced by driver code but may be used in conjuction with the
2481 * rest of the clock API. In the event of an error clk_register will return an
2482 * error code; drivers must test for an error code after calling clk_register.
2484 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
2487 struct clk_core *clk;
2489 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2491 pr_err("%s: could not allocate clk\n", __func__);
2496 clk->name = kstrdup_const(hw->init->name, GFP_KERNEL);
2498 pr_err("%s: could not allocate clk->name\n", __func__);
2502 clk->ops = hw->init->ops;
2503 if (dev && dev->driver)
2504 clk->owner = dev->driver->owner;
2506 clk->flags = hw->init->flags;
2507 clk->num_parents = hw->init->num_parents;
2510 /* allocate local copy in case parent_names is __initdata */
2511 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
2514 if (!clk->parent_names) {
2515 pr_err("%s: could not allocate clk->parent_names\n", __func__);
2517 goto fail_parent_names;
2521 /* copy each string name in case parent_names is __initdata */
2522 for (i = 0; i < clk->num_parents; i++) {
2523 clk->parent_names[i] = kstrdup_const(hw->init->parent_names[i],
2525 if (!clk->parent_names[i]) {
2526 pr_err("%s: could not copy parent_names\n", __func__);
2528 goto fail_parent_names_copy;
2532 INIT_HLIST_HEAD(&clk->clks);
2534 hw->clk = __clk_create_clk(hw, NULL, NULL);
2535 if (IS_ERR(hw->clk)) {
2536 pr_err("%s: could not allocate per-user clk\n", __func__);
2537 ret = PTR_ERR(hw->clk);
2538 goto fail_parent_names_copy;
2541 ret = __clk_init(dev, hw->clk);
2545 __clk_free_clk(hw->clk);
2548 fail_parent_names_copy:
2550 kfree_const(clk->parent_names[i]);
2551 kfree(clk->parent_names);
2553 kfree_const(clk->name);
2557 return ERR_PTR(ret);
2559 EXPORT_SYMBOL_GPL(clk_register);
2562 * Free memory allocated for a clock.
2563 * Caller must hold prepare_lock.
2565 static void __clk_release(struct kref *ref)
2567 struct clk_core *clk = container_of(ref, struct clk_core, ref);
2568 int i = clk->num_parents;
2570 lockdep_assert_held(&prepare_lock);
2572 kfree(clk->parents);
2574 kfree_const(clk->parent_names[i]);
2576 kfree(clk->parent_names);
2577 kfree_const(clk->name);
2582 * Empty clk_ops for unregistered clocks. These are used temporarily
2583 * after clk_unregister() was called on a clock and until last clock
2584 * consumer calls clk_put() and the struct clk object is freed.
2586 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2591 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2596 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2597 unsigned long parent_rate)
2602 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2607 static const struct clk_ops clk_nodrv_ops = {
2608 .enable = clk_nodrv_prepare_enable,
2609 .disable = clk_nodrv_disable_unprepare,
2610 .prepare = clk_nodrv_prepare_enable,
2611 .unprepare = clk_nodrv_disable_unprepare,
2612 .set_rate = clk_nodrv_set_rate,
2613 .set_parent = clk_nodrv_set_parent,
2617 * clk_unregister - unregister a currently registered clock
2618 * @clk: clock to unregister
2620 void clk_unregister(struct clk *clk)
2622 unsigned long flags;
2624 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2627 clk_debug_unregister(clk->core);
2631 if (clk->core->ops == &clk_nodrv_ops) {
2632 pr_err("%s: unregistered clock: %s\n", __func__,
2637 * Assign empty clock ops for consumers that might still hold
2638 * a reference to this clock.
2640 flags = clk_enable_lock();
2641 clk->core->ops = &clk_nodrv_ops;
2642 clk_enable_unlock(flags);
2644 if (!hlist_empty(&clk->core->children)) {
2645 struct clk_core *child;
2646 struct hlist_node *t;
2648 /* Reparent all children to the orphan list. */
2649 hlist_for_each_entry_safe(child, t, &clk->core->children,
2651 clk_core_set_parent(child, NULL);
2654 hlist_del_init(&clk->core->child_node);
2656 if (clk->core->prepare_count)
2657 pr_warn("%s: unregistering prepared clock: %s\n",
2658 __func__, clk->core->name);
2659 kref_put(&clk->core->ref, __clk_release);
2661 clk_prepare_unlock();
2663 EXPORT_SYMBOL_GPL(clk_unregister);
2665 static void devm_clk_release(struct device *dev, void *res)
2667 clk_unregister(*(struct clk **)res);
2671 * devm_clk_register - resource managed clk_register()
2672 * @dev: device that is registering this clock
2673 * @hw: link to hardware-specific clock data
2675 * Managed clk_register(). Clocks returned from this function are
2676 * automatically clk_unregister()ed on driver detach. See clk_register() for
2679 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2684 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2686 return ERR_PTR(-ENOMEM);
2688 clk = clk_register(dev, hw);
2691 devres_add(dev, clkp);
2698 EXPORT_SYMBOL_GPL(devm_clk_register);
2700 static int devm_clk_match(struct device *dev, void *res, void *data)
2702 struct clk *c = res;
2709 * devm_clk_unregister - resource managed clk_unregister()
2710 * @clk: clock to unregister
2712 * Deallocate a clock allocated with devm_clk_register(). Normally
2713 * this function will not need to be called and the resource management
2714 * code will ensure that the resource is freed.
2716 void devm_clk_unregister(struct device *dev, struct clk *clk)
2718 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2720 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2725 int __clk_get(struct clk *clk)
2727 struct clk_core *core = !clk ? NULL : clk->core;
2730 if (!try_module_get(core->owner))
2733 kref_get(&core->ref);
2738 void __clk_put(struct clk *clk)
2740 struct module *owner;
2742 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2747 hlist_del(&clk->clks_node);
2748 if (clk->min_rate > clk->core->req_rate ||
2749 clk->max_rate < clk->core->req_rate)
2750 clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
2752 owner = clk->core->owner;
2753 kref_put(&clk->core->ref, __clk_release);
2755 clk_prepare_unlock();
2762 /*** clk rate change notifiers ***/
2765 * clk_notifier_register - add a clk rate change notifier
2766 * @clk: struct clk * to watch
2767 * @nb: struct notifier_block * with callback info
2769 * Request notification when clk's rate changes. This uses an SRCU
2770 * notifier because we want it to block and notifier unregistrations are
2771 * uncommon. The callbacks associated with the notifier must not
2772 * re-enter into the clk framework by calling any top-level clk APIs;
2773 * this will cause a nested prepare_lock mutex.
2775 * In all notification cases cases (pre, post and abort rate change) the
2776 * original clock rate is passed to the callback via struct
2777 * clk_notifier_data.old_rate and the new frequency is passed via struct
2778 * clk_notifier_data.new_rate.
2780 * clk_notifier_register() must be called from non-atomic context.
2781 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2782 * allocation failure; otherwise, passes along the return value of
2783 * srcu_notifier_chain_register().
2785 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2787 struct clk_notifier *cn;
2795 /* search the list of notifiers for this clk */
2796 list_for_each_entry(cn, &clk_notifier_list, node)
2800 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2801 if (cn->clk != clk) {
2802 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2807 srcu_init_notifier_head(&cn->notifier_head);
2809 list_add(&cn->node, &clk_notifier_list);
2812 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2814 clk->core->notifier_count++;
2817 clk_prepare_unlock();
2821 EXPORT_SYMBOL_GPL(clk_notifier_register);
2824 * clk_notifier_unregister - remove a clk rate change notifier
2825 * @clk: struct clk *
2826 * @nb: struct notifier_block * with callback info
2828 * Request no further notification for changes to 'clk' and frees memory
2829 * allocated in clk_notifier_register.
2831 * Returns -EINVAL if called with null arguments; otherwise, passes
2832 * along the return value of srcu_notifier_chain_unregister().
2834 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2836 struct clk_notifier *cn = NULL;
2844 list_for_each_entry(cn, &clk_notifier_list, node)
2848 if (cn->clk == clk) {
2849 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2851 clk->core->notifier_count--;
2853 /* XXX the notifier code should handle this better */
2854 if (!cn->notifier_head.head) {
2855 srcu_cleanup_notifier_head(&cn->notifier_head);
2856 list_del(&cn->node);
2864 clk_prepare_unlock();
2868 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2872 * struct of_clk_provider - Clock provider registration structure
2873 * @link: Entry in global list of clock providers
2874 * @node: Pointer to device tree node of clock provider
2875 * @get: Get clock callback. Returns NULL or a struct clk for the
2876 * given clock specifier
2877 * @data: context pointer to be passed into @get callback
2879 struct of_clk_provider {
2880 struct list_head link;
2882 struct device_node *node;
2883 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2887 static const struct of_device_id __clk_of_table_sentinel
2888 __used __section(__clk_of_table_end);
2890 static LIST_HEAD(of_clk_providers);
2891 static DEFINE_MUTEX(of_clk_mutex);
2893 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2898 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2900 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2902 struct clk_onecell_data *clk_data = data;
2903 unsigned int idx = clkspec->args[0];
2905 if (idx >= clk_data->clk_num) {
2906 pr_err("%s: invalid clock index %d\n", __func__, idx);
2907 return ERR_PTR(-EINVAL);
2910 return clk_data->clks[idx];
2912 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2915 * of_clk_add_provider() - Register a clock provider for a node
2916 * @np: Device node pointer associated with clock provider
2917 * @clk_src_get: callback for decoding clock
2918 * @data: context pointer for @clk_src_get callback.
2920 int of_clk_add_provider(struct device_node *np,
2921 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2925 struct of_clk_provider *cp;
2928 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2932 cp->node = of_node_get(np);
2934 cp->get = clk_src_get;
2936 mutex_lock(&of_clk_mutex);
2937 list_add(&cp->link, &of_clk_providers);
2938 mutex_unlock(&of_clk_mutex);
2939 pr_debug("Added clock from %s\n", np->full_name);
2941 ret = of_clk_set_defaults(np, true);
2943 of_clk_del_provider(np);
2947 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2950 * of_clk_del_provider() - Remove a previously registered clock provider
2951 * @np: Device node pointer associated with clock provider
2953 void of_clk_del_provider(struct device_node *np)
2955 struct of_clk_provider *cp;
2957 mutex_lock(&of_clk_mutex);
2958 list_for_each_entry(cp, &of_clk_providers, link) {
2959 if (cp->node == np) {
2960 list_del(&cp->link);
2961 of_node_put(cp->node);
2966 mutex_unlock(&of_clk_mutex);
2968 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2970 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
2971 const char *dev_id, const char *con_id)
2973 struct of_clk_provider *provider;
2974 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2977 return ERR_PTR(-EINVAL);
2979 /* Check if we have such a provider in our array */
2980 mutex_lock(&of_clk_mutex);
2981 list_for_each_entry(provider, &of_clk_providers, link) {
2982 if (provider->node == clkspec->np)
2983 clk = provider->get(clkspec, provider->data);
2985 clk = __clk_create_clk(__clk_get_hw(clk), dev_id,
2988 if (!IS_ERR(clk) && !__clk_get(clk)) {
2989 __clk_free_clk(clk);
2990 clk = ERR_PTR(-ENOENT);
2996 mutex_unlock(&of_clk_mutex);
3002 * of_clk_get_from_provider() - Lookup a clock from a clock provider
3003 * @clkspec: pointer to a clock specifier data structure
3005 * This function looks up a struct clk from the registered list of clock
3006 * providers, an input is a clock specifier data structure as returned
3007 * from the of_parse_phandle_with_args() function call.
3009 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
3011 return __of_clk_get_from_provider(clkspec, NULL, __func__);
3014 int of_clk_get_parent_count(struct device_node *np)
3016 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
3018 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
3020 const char *of_clk_get_parent_name(struct device_node *np, int index)
3022 struct of_phandle_args clkspec;
3023 struct property *prop;
3024 const char *clk_name;
3033 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
3038 index = clkspec.args_count ? clkspec.args[0] : 0;
3041 /* if there is an indices property, use it to transfer the index
3042 * specified into an array offset for the clock-output-names property.
3044 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
3052 if (of_property_read_string_index(clkspec.np, "clock-output-names",
3055 clk_name = clkspec.np->name;
3057 of_node_put(clkspec.np);
3060 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
3062 struct clock_provider {
3063 of_clk_init_cb_t clk_init_cb;
3064 struct device_node *np;
3065 struct list_head node;
3068 static LIST_HEAD(clk_provider_list);
3071 * This function looks for a parent clock. If there is one, then it
3072 * checks that the provider for this parent clock was initialized, in
3073 * this case the parent clock will be ready.
3075 static int parent_ready(struct device_node *np)
3080 struct clk *clk = of_clk_get(np, i);
3082 /* this parent is ready we can check the next one */
3089 /* at least one parent is not ready, we exit now */
3090 if (PTR_ERR(clk) == -EPROBE_DEFER)
3094 * Here we make assumption that the device tree is
3095 * written correctly. So an error means that there is
3096 * no more parent. As we didn't exit yet, then the
3097 * previous parent are ready. If there is no clock
3098 * parent, no need to wait for them, then we can
3099 * consider their absence as being ready
3106 * of_clk_init() - Scan and init clock providers from the DT
3107 * @matches: array of compatible values and init functions for providers.
3109 * This function scans the device tree for matching clock providers
3110 * and calls their initialization functions. It also does it by trying
3111 * to follow the dependencies.
3113 void __init of_clk_init(const struct of_device_id *matches)
3115 const struct of_device_id *match;
3116 struct device_node *np;
3117 struct clock_provider *clk_provider, *next;
3122 matches = &__clk_of_table;
3124 /* First prepare the list of the clocks providers */
3125 for_each_matching_node_and_match(np, matches, &match) {
3126 struct clock_provider *parent =
3127 kzalloc(sizeof(struct clock_provider), GFP_KERNEL);
3129 parent->clk_init_cb = match->data;
3131 list_add_tail(&parent->node, &clk_provider_list);
3134 while (!list_empty(&clk_provider_list)) {
3135 is_init_done = false;
3136 list_for_each_entry_safe(clk_provider, next,
3137 &clk_provider_list, node) {
3138 if (force || parent_ready(clk_provider->np)) {
3140 clk_provider->clk_init_cb(clk_provider->np);
3141 of_clk_set_defaults(clk_provider->np, true);
3143 list_del(&clk_provider->node);
3144 kfree(clk_provider);
3145 is_init_done = true;
3150 * We didn't manage to initialize any of the
3151 * remaining providers during the last loop, so now we
3152 * initialize all the remaining ones unconditionally
3153 * in case the clock parent was not mandatory