2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
12 #include <linux/clk-private.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock.h>
16 #include <linux/err.h>
17 #include <linux/list.h>
18 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
26 static DEFINE_SPINLOCK(enable_lock);
27 static DEFINE_MUTEX(prepare_lock);
29 static struct task_struct *prepare_owner;
30 static struct task_struct *enable_owner;
32 static int prepare_refcnt;
33 static int enable_refcnt;
35 static HLIST_HEAD(clk_root_list);
36 static HLIST_HEAD(clk_orphan_list);
37 static LIST_HEAD(clk_notifier_list);
40 static void clk_prepare_lock(void)
42 if (!mutex_trylock(&prepare_lock)) {
43 if (prepare_owner == current) {
47 mutex_lock(&prepare_lock);
49 WARN_ON_ONCE(prepare_owner != NULL);
50 WARN_ON_ONCE(prepare_refcnt != 0);
51 prepare_owner = current;
55 static void clk_prepare_unlock(void)
57 WARN_ON_ONCE(prepare_owner != current);
58 WARN_ON_ONCE(prepare_refcnt == 0);
63 mutex_unlock(&prepare_lock);
66 static unsigned long clk_enable_lock(void)
70 if (!spin_trylock_irqsave(&enable_lock, flags)) {
71 if (enable_owner == current) {
75 spin_lock_irqsave(&enable_lock, flags);
77 WARN_ON_ONCE(enable_owner != NULL);
78 WARN_ON_ONCE(enable_refcnt != 0);
79 enable_owner = current;
84 static void clk_enable_unlock(unsigned long flags)
86 WARN_ON_ONCE(enable_owner != current);
87 WARN_ON_ONCE(enable_refcnt == 0);
92 spin_unlock_irqrestore(&enable_lock, flags);
95 /*** debugfs support ***/
97 #ifdef CONFIG_DEBUG_FS
98 #include <linux/debugfs.h>
100 static struct dentry *rootdir;
101 static int inited = 0;
103 static struct hlist_head *all_lists[] = {
109 static struct hlist_head *orphan_list[] = {
114 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
119 seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu\n",
121 30 - level * 3, c->name,
122 c->enable_count, c->prepare_count, clk_get_rate(c),
123 clk_get_accuracy(c));
126 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
134 clk_summary_show_one(s, c, level);
136 hlist_for_each_entry(child, &c->children, child_node)
137 clk_summary_show_subtree(s, child, level + 1);
140 static int clk_summary_show(struct seq_file *s, void *data)
143 struct hlist_head **lists = (struct hlist_head **)s->private;
145 seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy\n");
146 seq_puts(s, "--------------------------------------------------------------------------------\n");
150 for (; *lists; lists++)
151 hlist_for_each_entry(c, *lists, child_node)
152 clk_summary_show_subtree(s, c, 0);
154 clk_prepare_unlock();
160 static int clk_summary_open(struct inode *inode, struct file *file)
162 return single_open(file, clk_summary_show, inode->i_private);
165 static const struct file_operations clk_summary_fops = {
166 .open = clk_summary_open,
169 .release = single_release,
172 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
177 seq_printf(s, "\"%s\": { ", c->name);
178 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
179 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
180 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
181 seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
184 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
191 clk_dump_one(s, c, level);
193 hlist_for_each_entry(child, &c->children, child_node) {
195 clk_dump_subtree(s, child, level + 1);
201 static int clk_dump(struct seq_file *s, void *data)
204 bool first_node = true;
205 struct hlist_head **lists = (struct hlist_head **)s->private;
211 for (; *lists; lists++) {
212 hlist_for_each_entry(c, *lists, child_node) {
216 clk_dump_subtree(s, c, 0);
220 clk_prepare_unlock();
227 static int clk_dump_open(struct inode *inode, struct file *file)
229 return single_open(file, clk_dump, inode->i_private);
232 static const struct file_operations clk_dump_fops = {
233 .open = clk_dump_open,
236 .release = single_release,
239 /* caller must hold prepare_lock */
240 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
245 if (!clk || !pdentry) {
250 d = debugfs_create_dir(clk->name, pdentry);
256 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
261 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
262 (u32 *)&clk->accuracy);
266 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
271 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
272 (u32 *)&clk->prepare_count);
276 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
277 (u32 *)&clk->enable_count);
281 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
282 (u32 *)&clk->notifier_count);
286 if (clk->ops->debug_init)
287 if (clk->ops->debug_init(clk->hw, clk->dentry))
294 debugfs_remove_recursive(clk->dentry);
300 /* caller must hold prepare_lock */
301 static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
306 if (!clk || !pdentry)
309 ret = clk_debug_create_one(clk, pdentry);
314 hlist_for_each_entry(child, &clk->children, child_node)
315 clk_debug_create_subtree(child, pdentry);
323 * clk_debug_register - add a clk node to the debugfs clk tree
324 * @clk: the clk being added to the debugfs clk tree
326 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
327 * initialized. Otherwise it bails out early since the debugfs clk tree
328 * will be created lazily by clk_debug_init as part of a late_initcall.
330 * Caller must hold prepare_lock. Only clk_init calls this function (so
331 * far) so this is taken care.
333 static int clk_debug_register(struct clk *clk)
340 ret = clk_debug_create_subtree(clk, rootdir);
347 * clk_debug_unregister - remove a clk node from the debugfs clk tree
348 * @clk: the clk being removed from the debugfs clk tree
350 * Dynamically removes a clk and all it's children clk nodes from the
351 * debugfs clk tree if clk->dentry points to debugfs created by
352 * clk_debug_register in __clk_init.
354 * Caller must hold prepare_lock.
356 static void clk_debug_unregister(struct clk *clk)
358 debugfs_remove_recursive(clk->dentry);
361 struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
362 void *data, const struct file_operations *fops)
364 struct dentry *d = NULL;
367 d = debugfs_create_file(name, mode, clk->dentry, data, fops);
371 EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
374 * clk_debug_init - lazily create the debugfs clk tree visualization
376 * clks are often initialized very early during boot before memory can
377 * be dynamically allocated and well before debugfs is setup.
378 * clk_debug_init walks the clk tree hierarchy while holding
379 * prepare_lock and creates the topology as part of a late_initcall,
380 * thus insuring that clks initialized very early will still be
381 * represented in the debugfs clk tree. This function should only be
382 * called once at boot-time, and all other clks added dynamically will
383 * be done so with clk_debug_register.
385 static int __init clk_debug_init(void)
390 rootdir = debugfs_create_dir("clk", NULL);
395 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists,
400 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists,
405 d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir,
406 &orphan_list, &clk_summary_fops);
410 d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir,
411 &orphan_list, &clk_dump_fops);
417 hlist_for_each_entry(clk, &clk_root_list, child_node)
418 clk_debug_create_subtree(clk, rootdir);
420 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
421 clk_debug_create_subtree(clk, rootdir);
425 clk_prepare_unlock();
429 late_initcall(clk_debug_init);
431 static inline int clk_debug_register(struct clk *clk) { return 0; }
432 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
435 static inline void clk_debug_unregister(struct clk *clk)
440 /* caller must hold prepare_lock */
441 static void clk_unprepare_unused_subtree(struct clk *clk)
448 hlist_for_each_entry(child, &clk->children, child_node)
449 clk_unprepare_unused_subtree(child);
451 if (clk->prepare_count)
454 if (clk->flags & CLK_IGNORE_UNUSED)
457 if (__clk_is_prepared(clk)) {
458 if (clk->ops->unprepare_unused)
459 clk->ops->unprepare_unused(clk->hw);
460 else if (clk->ops->unprepare)
461 clk->ops->unprepare(clk->hw);
465 /* caller must hold prepare_lock */
466 static void clk_disable_unused_subtree(struct clk *clk)
474 hlist_for_each_entry(child, &clk->children, child_node)
475 clk_disable_unused_subtree(child);
477 flags = clk_enable_lock();
479 if (clk->enable_count)
482 if (clk->flags & CLK_IGNORE_UNUSED)
486 * some gate clocks have special needs during the disable-unused
487 * sequence. call .disable_unused if available, otherwise fall
490 if (__clk_is_enabled(clk)) {
491 if (clk->ops->disable_unused)
492 clk->ops->disable_unused(clk->hw);
493 else if (clk->ops->disable)
494 clk->ops->disable(clk->hw);
498 clk_enable_unlock(flags);
504 static bool clk_ignore_unused;
505 static int __init clk_ignore_unused_setup(char *__unused)
507 clk_ignore_unused = true;
510 __setup("clk_ignore_unused", clk_ignore_unused_setup);
512 static int clk_disable_unused(void)
516 if (clk_ignore_unused) {
517 pr_warn("clk: Not disabling unused clocks\n");
523 hlist_for_each_entry(clk, &clk_root_list, child_node)
524 clk_disable_unused_subtree(clk);
526 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
527 clk_disable_unused_subtree(clk);
529 hlist_for_each_entry(clk, &clk_root_list, child_node)
530 clk_unprepare_unused_subtree(clk);
532 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
533 clk_unprepare_unused_subtree(clk);
535 clk_prepare_unlock();
539 late_initcall_sync(clk_disable_unused);
541 /*** helper functions ***/
543 const char *__clk_get_name(struct clk *clk)
545 return !clk ? NULL : clk->name;
547 EXPORT_SYMBOL_GPL(__clk_get_name);
549 struct clk_hw *__clk_get_hw(struct clk *clk)
551 return !clk ? NULL : clk->hw;
553 EXPORT_SYMBOL_GPL(__clk_get_hw);
555 u8 __clk_get_num_parents(struct clk *clk)
557 return !clk ? 0 : clk->num_parents;
559 EXPORT_SYMBOL_GPL(__clk_get_num_parents);
561 struct clk *__clk_get_parent(struct clk *clk)
563 return !clk ? NULL : clk->parent;
565 EXPORT_SYMBOL_GPL(__clk_get_parent);
567 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
569 if (!clk || index >= clk->num_parents)
571 else if (!clk->parents)
572 return __clk_lookup(clk->parent_names[index]);
573 else if (!clk->parents[index])
574 return clk->parents[index] =
575 __clk_lookup(clk->parent_names[index]);
577 return clk->parents[index];
579 EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
581 unsigned int __clk_get_enable_count(struct clk *clk)
583 return !clk ? 0 : clk->enable_count;
586 unsigned int __clk_get_prepare_count(struct clk *clk)
588 return !clk ? 0 : clk->prepare_count;
591 unsigned long __clk_get_rate(struct clk *clk)
602 if (clk->flags & CLK_IS_ROOT)
611 EXPORT_SYMBOL_GPL(__clk_get_rate);
613 unsigned long __clk_get_accuracy(struct clk *clk)
618 return clk->accuracy;
621 unsigned long __clk_get_flags(struct clk *clk)
623 return !clk ? 0 : clk->flags;
625 EXPORT_SYMBOL_GPL(__clk_get_flags);
627 bool __clk_is_prepared(struct clk *clk)
635 * .is_prepared is optional for clocks that can prepare
636 * fall back to software usage counter if it is missing
638 if (!clk->ops->is_prepared) {
639 ret = clk->prepare_count ? 1 : 0;
643 ret = clk->ops->is_prepared(clk->hw);
648 bool __clk_is_enabled(struct clk *clk)
656 * .is_enabled is only mandatory for clocks that gate
657 * fall back to software usage counter if .is_enabled is missing
659 if (!clk->ops->is_enabled) {
660 ret = clk->enable_count ? 1 : 0;
664 ret = clk->ops->is_enabled(clk->hw);
668 EXPORT_SYMBOL_GPL(__clk_is_enabled);
670 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
675 if (!strcmp(clk->name, name))
678 hlist_for_each_entry(child, &clk->children, child_node) {
679 ret = __clk_lookup_subtree(name, child);
687 struct clk *__clk_lookup(const char *name)
689 struct clk *root_clk;
695 /* search the 'proper' clk tree first */
696 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
697 ret = __clk_lookup_subtree(name, root_clk);
702 /* if not found, then search the orphan tree */
703 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
704 ret = __clk_lookup_subtree(name, root_clk);
713 * Helper for finding best parent to provide a given frequency. This can be used
714 * directly as a determine_rate callback (e.g. for a mux), or from a more
715 * complex clock that may combine a mux with other operations.
717 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
718 unsigned long *best_parent_rate,
719 struct clk **best_parent_p)
721 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
723 unsigned long parent_rate, best = 0;
725 /* if NO_REPARENT flag set, pass through to current parent */
726 if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
727 parent = clk->parent;
728 if (clk->flags & CLK_SET_RATE_PARENT)
729 best = __clk_round_rate(parent, rate);
731 best = __clk_get_rate(parent);
733 best = __clk_get_rate(clk);
737 /* find the parent that can provide the fastest rate <= rate */
738 num_parents = clk->num_parents;
739 for (i = 0; i < num_parents; i++) {
740 parent = clk_get_parent_by_index(clk, i);
743 if (clk->flags & CLK_SET_RATE_PARENT)
744 parent_rate = __clk_round_rate(parent, rate);
746 parent_rate = __clk_get_rate(parent);
747 if (parent_rate <= rate && parent_rate > best) {
748 best_parent = parent;
755 *best_parent_p = best_parent;
756 *best_parent_rate = best;
760 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
764 void __clk_unprepare(struct clk *clk)
769 if (WARN_ON(clk->prepare_count == 0))
772 if (--clk->prepare_count > 0)
775 WARN_ON(clk->enable_count > 0);
777 if (clk->ops->unprepare)
778 clk->ops->unprepare(clk->hw);
780 __clk_unprepare(clk->parent);
784 * clk_unprepare - undo preparation of a clock source
785 * @clk: the clk being unprepared
787 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
788 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
789 * if the operation may sleep. One example is a clk which is accessed over
790 * I2c. In the complex case a clk gate operation may require a fast and a slow
791 * part. It is this reason that clk_unprepare and clk_disable are not mutually
792 * exclusive. In fact clk_disable must be called before clk_unprepare.
794 void clk_unprepare(struct clk *clk)
796 if (IS_ERR_OR_NULL(clk))
800 __clk_unprepare(clk);
801 clk_prepare_unlock();
803 EXPORT_SYMBOL_GPL(clk_unprepare);
805 int __clk_prepare(struct clk *clk)
812 if (clk->prepare_count == 0) {
813 ret = __clk_prepare(clk->parent);
817 if (clk->ops->prepare) {
818 ret = clk->ops->prepare(clk->hw);
820 __clk_unprepare(clk->parent);
826 clk->prepare_count++;
832 * clk_prepare - prepare a clock source
833 * @clk: the clk being prepared
835 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
836 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
837 * operation may sleep. One example is a clk which is accessed over I2c. In
838 * the complex case a clk ungate operation may require a fast and a slow part.
839 * It is this reason that clk_prepare and clk_enable are not mutually
840 * exclusive. In fact clk_prepare must be called before clk_enable.
841 * Returns 0 on success, -EERROR otherwise.
843 int clk_prepare(struct clk *clk)
848 ret = __clk_prepare(clk);
849 clk_prepare_unlock();
853 EXPORT_SYMBOL_GPL(clk_prepare);
855 static void __clk_disable(struct clk *clk)
860 if (WARN_ON(clk->enable_count == 0))
863 if (--clk->enable_count > 0)
866 if (clk->ops->disable)
867 clk->ops->disable(clk->hw);
869 __clk_disable(clk->parent);
873 * clk_disable - gate a clock
874 * @clk: the clk being gated
876 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
877 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
878 * clk if the operation is fast and will never sleep. One example is a
879 * SoC-internal clk which is controlled via simple register writes. In the
880 * complex case a clk gate operation may require a fast and a slow part. It is
881 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
882 * In fact clk_disable must be called before clk_unprepare.
884 void clk_disable(struct clk *clk)
888 if (IS_ERR_OR_NULL(clk))
891 flags = clk_enable_lock();
893 clk_enable_unlock(flags);
895 EXPORT_SYMBOL_GPL(clk_disable);
897 static int __clk_enable(struct clk *clk)
904 if (WARN_ON(clk->prepare_count == 0))
907 if (clk->enable_count == 0) {
908 ret = __clk_enable(clk->parent);
913 if (clk->ops->enable) {
914 ret = clk->ops->enable(clk->hw);
916 __clk_disable(clk->parent);
927 * clk_enable - ungate a clock
928 * @clk: the clk being ungated
930 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
931 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
932 * if the operation will never sleep. One example is a SoC-internal clk which
933 * is controlled via simple register writes. In the complex case a clk ungate
934 * operation may require a fast and a slow part. It is this reason that
935 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
936 * must be called before clk_enable. Returns 0 on success, -EERROR
939 int clk_enable(struct clk *clk)
944 flags = clk_enable_lock();
945 ret = __clk_enable(clk);
946 clk_enable_unlock(flags);
950 EXPORT_SYMBOL_GPL(clk_enable);
953 * __clk_round_rate - round the given rate for a clk
954 * @clk: round the rate of this clock
955 * @rate: the rate which is to be rounded
957 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
959 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
961 unsigned long parent_rate = 0;
967 parent = clk->parent;
969 parent_rate = parent->rate;
971 if (clk->ops->determine_rate)
972 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
974 else if (clk->ops->round_rate)
975 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
976 else if (clk->flags & CLK_SET_RATE_PARENT)
977 return __clk_round_rate(clk->parent, rate);
981 EXPORT_SYMBOL_GPL(__clk_round_rate);
984 * clk_round_rate - round the given rate for a clk
985 * @clk: the clk for which we are rounding a rate
986 * @rate: the rate which is to be rounded
988 * Takes in a rate as input and rounds it to a rate that the clk can actually
989 * use which is then returned. If clk doesn't support round_rate operation
990 * then the parent rate is returned.
992 long clk_round_rate(struct clk *clk, unsigned long rate)
997 ret = __clk_round_rate(clk, rate);
998 clk_prepare_unlock();
1002 EXPORT_SYMBOL_GPL(clk_round_rate);
1005 * __clk_notify - call clk notifier chain
1006 * @clk: struct clk * that is changing rate
1007 * @msg: clk notifier type (see include/linux/clk.h)
1008 * @old_rate: old clk rate
1009 * @new_rate: new clk rate
1011 * Triggers a notifier call chain on the clk rate-change notification
1012 * for 'clk'. Passes a pointer to the struct clk and the previous
1013 * and current rates to the notifier callback. Intended to be called by
1014 * internal clock code only. Returns NOTIFY_DONE from the last driver
1015 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1016 * a driver returns that.
1018 static int __clk_notify(struct clk *clk, unsigned long msg,
1019 unsigned long old_rate, unsigned long new_rate)
1021 struct clk_notifier *cn;
1022 struct clk_notifier_data cnd;
1023 int ret = NOTIFY_DONE;
1026 cnd.old_rate = old_rate;
1027 cnd.new_rate = new_rate;
1029 list_for_each_entry(cn, &clk_notifier_list, node) {
1030 if (cn->clk == clk) {
1031 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1041 * __clk_recalc_accuracies
1042 * @clk: first clk in the subtree
1044 * Walks the subtree of clks starting with clk and recalculates accuracies as
1045 * it goes. Note that if a clk does not implement the .recalc_accuracy
1046 * callback then it is assumed that the clock will take on the accuracy of it's
1049 * Caller must hold prepare_lock.
1051 static void __clk_recalc_accuracies(struct clk *clk)
1053 unsigned long parent_accuracy = 0;
1057 parent_accuracy = clk->parent->accuracy;
1059 if (clk->ops->recalc_accuracy)
1060 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1063 clk->accuracy = parent_accuracy;
1065 hlist_for_each_entry(child, &clk->children, child_node)
1066 __clk_recalc_accuracies(child);
1070 * clk_get_accuracy - return the accuracy of clk
1071 * @clk: the clk whose accuracy is being returned
1073 * Simply returns the cached accuracy of the clk, unless
1074 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1076 * If clk is NULL then returns 0.
1078 long clk_get_accuracy(struct clk *clk)
1080 unsigned long accuracy;
1083 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1084 __clk_recalc_accuracies(clk);
1086 accuracy = __clk_get_accuracy(clk);
1087 clk_prepare_unlock();
1091 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1093 static unsigned long clk_recalc(struct clk *clk, unsigned long parent_rate)
1095 if (clk->ops->recalc_rate)
1096 return clk->ops->recalc_rate(clk->hw, parent_rate);
1101 * __clk_recalc_rates
1102 * @clk: first clk in the subtree
1103 * @msg: notification type (see include/linux/clk.h)
1105 * Walks the subtree of clks starting with clk and recalculates rates as it
1106 * goes. Note that if a clk does not implement the .recalc_rate callback then
1107 * it is assumed that the clock will take on the rate of its parent.
1109 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1112 * Caller must hold prepare_lock.
1114 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
1116 unsigned long old_rate;
1117 unsigned long parent_rate = 0;
1120 old_rate = clk->rate;
1123 parent_rate = clk->parent->rate;
1125 clk->rate = clk_recalc(clk, parent_rate);
1128 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1129 * & ABORT_RATE_CHANGE notifiers
1131 if (clk->notifier_count && msg)
1132 __clk_notify(clk, msg, old_rate, clk->rate);
1134 hlist_for_each_entry(child, &clk->children, child_node)
1135 __clk_recalc_rates(child, msg);
1139 * clk_get_rate - return the rate of clk
1140 * @clk: the clk whose rate is being returned
1142 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1143 * is set, which means a recalc_rate will be issued.
1144 * If clk is NULL then returns 0.
1146 unsigned long clk_get_rate(struct clk *clk)
1152 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1153 __clk_recalc_rates(clk, 0);
1155 rate = __clk_get_rate(clk);
1156 clk_prepare_unlock();
1160 EXPORT_SYMBOL_GPL(clk_get_rate);
1162 static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1166 if (!clk->parents) {
1167 clk->parents = kcalloc(clk->num_parents,
1168 sizeof(struct clk *), GFP_KERNEL);
1174 * find index of new parent clock using cached parent ptrs,
1175 * or if not yet cached, use string name comparison and cache
1176 * them now to avoid future calls to __clk_lookup.
1178 for (i = 0; i < clk->num_parents; i++) {
1179 if (clk->parents[i] == parent)
1182 if (clk->parents[i])
1185 if (!strcmp(clk->parent_names[i], parent->name)) {
1186 clk->parents[i] = __clk_lookup(parent->name);
1194 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1196 hlist_del(&clk->child_node);
1199 /* avoid duplicate POST_RATE_CHANGE notifications */
1200 if (new_parent->new_child == clk)
1201 new_parent->new_child = NULL;
1203 hlist_add_head(&clk->child_node, &new_parent->children);
1205 hlist_add_head(&clk->child_node, &clk_orphan_list);
1208 clk->parent = new_parent;
1211 static struct clk *__clk_set_parent_before(struct clk *clk, struct clk *parent)
1213 unsigned long flags;
1214 struct clk *old_parent = clk->parent;
1217 * Migrate prepare state between parents and prevent race with
1220 * If the clock is not prepared, then a race with
1221 * clk_enable/disable() is impossible since we already have the
1222 * prepare lock (future calls to clk_enable() need to be preceded by
1225 * If the clock is prepared, migrate the prepared state to the new
1226 * parent and also protect against a race with clk_enable() by
1227 * forcing the clock and the new parent on. This ensures that all
1228 * future calls to clk_enable() are practically NOPs with respect to
1229 * hardware and software states.
1231 * See also: Comment for clk_set_parent() below.
1233 if (clk->prepare_count) {
1234 __clk_prepare(parent);
1239 /* update the clk tree topology */
1240 flags = clk_enable_lock();
1241 clk_reparent(clk, parent);
1242 clk_enable_unlock(flags);
1247 static void __clk_set_parent_after(struct clk *clk, struct clk *parent,
1248 struct clk *old_parent)
1251 * Finish the migration of prepare state and undo the changes done
1252 * for preventing a race with clk_enable().
1254 if (clk->prepare_count) {
1256 clk_disable(old_parent);
1257 __clk_unprepare(old_parent);
1261 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1263 unsigned long flags;
1265 struct clk *old_parent;
1267 old_parent = __clk_set_parent_before(clk, parent);
1269 /* change clock input source */
1270 if (parent && clk->ops->set_parent)
1271 ret = clk->ops->set_parent(clk->hw, p_index);
1274 flags = clk_enable_lock();
1275 clk_reparent(clk, old_parent);
1276 clk_enable_unlock(flags);
1278 if (clk->prepare_count) {
1280 clk_disable(parent);
1281 __clk_unprepare(parent);
1286 __clk_set_parent_after(clk, parent, old_parent);
1292 * __clk_speculate_rates
1293 * @clk: first clk in the subtree
1294 * @parent_rate: the "future" rate of clk's parent
1296 * Walks the subtree of clks starting with clk, speculating rates as it
1297 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1299 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1300 * pre-rate change notifications and returns early if no clks in the
1301 * subtree have subscribed to the notifications. Note that if a clk does not
1302 * implement the .recalc_rate callback then it is assumed that the clock will
1303 * take on the rate of its parent.
1305 * Caller must hold prepare_lock.
1307 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1310 unsigned long new_rate;
1311 int ret = NOTIFY_DONE;
1313 new_rate = clk_recalc(clk, parent_rate);
1315 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1316 if (clk->notifier_count)
1317 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1319 if (ret & NOTIFY_STOP_MASK) {
1320 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1321 __func__, clk->name, ret);
1325 hlist_for_each_entry(child, &clk->children, child_node) {
1326 ret = __clk_speculate_rates(child, new_rate);
1327 if (ret & NOTIFY_STOP_MASK)
1335 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1336 struct clk *new_parent, u8 p_index)
1340 clk->new_rate = new_rate;
1341 clk->new_parent = new_parent;
1342 clk->new_parent_index = p_index;
1343 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1344 clk->new_child = NULL;
1345 if (new_parent && new_parent != clk->parent)
1346 new_parent->new_child = clk;
1348 hlist_for_each_entry(child, &clk->children, child_node) {
1349 child->new_rate = clk_recalc(child, new_rate);
1350 clk_calc_subtree(child, child->new_rate, NULL, 0);
1355 * calculate the new rates returning the topmost clock that has to be
1358 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1360 struct clk *top = clk;
1361 struct clk *old_parent, *parent;
1362 unsigned long best_parent_rate = 0;
1363 unsigned long new_rate;
1367 if (IS_ERR_OR_NULL(clk))
1370 /* save parent rate, if it exists */
1371 parent = old_parent = clk->parent;
1373 best_parent_rate = parent->rate;
1375 /* find the closest rate and parent clk/rate */
1376 if (clk->ops->determine_rate) {
1377 new_rate = clk->ops->determine_rate(clk->hw, rate,
1380 } else if (clk->ops->round_rate) {
1381 new_rate = clk->ops->round_rate(clk->hw, rate,
1383 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1384 /* pass-through clock without adjustable parent */
1385 clk->new_rate = clk->rate;
1388 /* pass-through clock with adjustable parent */
1389 top = clk_calc_new_rates(parent, rate);
1390 new_rate = parent->new_rate;
1394 /* some clocks must be gated to change parent */
1395 if (parent != old_parent &&
1396 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1397 pr_debug("%s: %s not gated but wants to reparent\n",
1398 __func__, clk->name);
1402 /* try finding the new parent index */
1404 p_index = clk_fetch_parent_index(clk, parent);
1406 pr_debug("%s: clk %s can not be parent of clk %s\n",
1407 __func__, parent->name, clk->name);
1412 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1413 best_parent_rate != parent->rate)
1414 top = clk_calc_new_rates(parent, best_parent_rate);
1417 clk_calc_subtree(clk, new_rate, parent, p_index);
1423 * Notify about rate changes in a subtree. Always walk down the whole tree
1424 * so that in case of an error we can walk down the whole tree again and
1427 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1429 struct clk *child, *tmp_clk, *fail_clk = NULL;
1430 int ret = NOTIFY_DONE;
1432 if (clk->rate == clk->new_rate)
1435 if (clk->notifier_count) {
1436 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1437 if (ret & NOTIFY_STOP_MASK)
1441 hlist_for_each_entry(child, &clk->children, child_node) {
1442 /* Skip children who will be reparented to another clock */
1443 if (child->new_parent && child->new_parent != clk)
1445 tmp_clk = clk_propagate_rate_change(child, event);
1450 /* handle the new child who might not be in clk->children yet */
1451 if (clk->new_child) {
1452 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1461 * walk down a subtree and set the new rates notifying the rate
1464 static void clk_change_rate(struct clk *clk)
1467 unsigned long old_rate;
1468 unsigned long best_parent_rate = 0;
1469 bool skip_set_rate = false;
1470 struct clk *old_parent;
1472 old_rate = clk->rate;
1474 if (clk->new_parent)
1475 best_parent_rate = clk->new_parent->rate;
1476 else if (clk->parent)
1477 best_parent_rate = clk->parent->rate;
1479 if (clk->new_parent && clk->new_parent != clk->parent) {
1480 old_parent = __clk_set_parent_before(clk, clk->new_parent);
1482 if (clk->ops->set_rate_and_parent) {
1483 skip_set_rate = true;
1484 clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
1486 clk->new_parent_index);
1487 } else if (clk->ops->set_parent) {
1488 clk->ops->set_parent(clk->hw, clk->new_parent_index);
1491 __clk_set_parent_after(clk, clk->new_parent, old_parent);
1494 if (!skip_set_rate && clk->ops->set_rate)
1495 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1497 clk->rate = clk_recalc(clk, best_parent_rate);
1499 if (clk->notifier_count && old_rate != clk->rate)
1500 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1502 hlist_for_each_entry(child, &clk->children, child_node) {
1503 /* Skip children who will be reparented to another clock */
1504 if (child->new_parent && child->new_parent != clk)
1506 clk_change_rate(child);
1509 /* handle the new child who might not be in clk->children yet */
1511 clk_change_rate(clk->new_child);
1515 * clk_set_rate - specify a new rate for clk
1516 * @clk: the clk whose rate is being changed
1517 * @rate: the new rate for clk
1519 * In the simplest case clk_set_rate will only adjust the rate of clk.
1521 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1522 * propagate up to clk's parent; whether or not this happens depends on the
1523 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1524 * after calling .round_rate then upstream parent propagation is ignored. If
1525 * *parent_rate comes back with a new rate for clk's parent then we propagate
1526 * up to clk's parent and set its rate. Upward propagation will continue
1527 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1528 * .round_rate stops requesting changes to clk's parent_rate.
1530 * Rate changes are accomplished via tree traversal that also recalculates the
1531 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1533 * Returns 0 on success, -EERROR otherwise.
1535 int clk_set_rate(struct clk *clk, unsigned long rate)
1537 struct clk *top, *fail_clk;
1543 /* prevent racing with updates to the clock topology */
1546 /* bail early if nothing to do */
1547 if (rate == clk_get_rate(clk))
1550 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1555 /* calculate new rates and get the topmost changed clock */
1556 top = clk_calc_new_rates(clk, rate);
1562 /* notify that we are about to change rates */
1563 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1565 pr_debug("%s: failed to set %s rate\n", __func__,
1567 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1572 /* change the rates */
1573 clk_change_rate(top);
1576 clk_prepare_unlock();
1580 EXPORT_SYMBOL_GPL(clk_set_rate);
1583 * clk_get_parent - return the parent of a clk
1584 * @clk: the clk whose parent gets returned
1586 * Simply returns clk->parent. Returns NULL if clk is NULL.
1588 struct clk *clk_get_parent(struct clk *clk)
1593 parent = __clk_get_parent(clk);
1594 clk_prepare_unlock();
1598 EXPORT_SYMBOL_GPL(clk_get_parent);
1601 * .get_parent is mandatory for clocks with multiple possible parents. It is
1602 * optional for single-parent clocks. Always call .get_parent if it is
1603 * available and WARN if it is missing for multi-parent clocks.
1605 * For single-parent clocks without .get_parent, first check to see if the
1606 * .parents array exists, and if so use it to avoid an expensive tree
1607 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1609 static struct clk *__clk_init_parent(struct clk *clk)
1611 struct clk *ret = NULL;
1614 /* handle the trivial cases */
1616 if (!clk->num_parents)
1619 if (clk->num_parents == 1) {
1620 if (IS_ERR_OR_NULL(clk->parent))
1621 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1626 if (!clk->ops->get_parent) {
1627 WARN(!clk->ops->get_parent,
1628 "%s: multi-parent clocks must implement .get_parent\n",
1634 * Do our best to cache parent clocks in clk->parents. This prevents
1635 * unnecessary and expensive calls to __clk_lookup. We don't set
1636 * clk->parent here; that is done by the calling function
1639 index = clk->ops->get_parent(clk->hw);
1643 kcalloc(clk->num_parents, sizeof(struct clk *),
1646 ret = clk_get_parent_by_index(clk, index);
1652 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1654 clk_reparent(clk, new_parent);
1655 __clk_recalc_accuracies(clk);
1656 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1660 * clk_set_parent - switch the parent of a mux clk
1661 * @clk: the mux clk whose input we are switching
1662 * @parent: the new input to clk
1664 * Re-parent clk to use parent as its new input source. If clk is in
1665 * prepared state, the clk will get enabled for the duration of this call. If
1666 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1667 * that, the reparenting is glitchy in hardware, etc), use the
1668 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1670 * After successfully changing clk's parent clk_set_parent will update the
1671 * clk topology, sysfs topology and propagate rate recalculation via
1672 * __clk_recalc_rates.
1674 * Returns 0 on success, -EERROR otherwise.
1676 int clk_set_parent(struct clk *clk, struct clk *parent)
1680 unsigned long p_rate = 0;
1685 /* verify ops for for multi-parent clks */
1686 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1689 /* prevent racing with updates to the clock topology */
1692 if (clk->parent == parent)
1695 /* check that we are allowed to re-parent if the clock is in use */
1696 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1701 /* try finding the new parent index */
1703 p_index = clk_fetch_parent_index(clk, parent);
1704 p_rate = parent->rate;
1706 pr_debug("%s: clk %s can not be parent of clk %s\n",
1707 __func__, parent->name, clk->name);
1713 /* propagate PRE_RATE_CHANGE notifications */
1714 ret = __clk_speculate_rates(clk, p_rate);
1716 /* abort if a driver objects */
1717 if (ret & NOTIFY_STOP_MASK)
1720 /* do the re-parent */
1721 ret = __clk_set_parent(clk, parent, p_index);
1723 /* propagate rate an accuracy recalculation accordingly */
1725 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1727 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1728 __clk_recalc_accuracies(clk);
1732 clk_prepare_unlock();
1736 EXPORT_SYMBOL_GPL(clk_set_parent);
1739 * __clk_init - initialize the data structures in a struct clk
1740 * @dev: device initializing this clk, placeholder for now
1741 * @clk: clk being initialized
1743 * Initializes the lists in struct clk, queries the hardware for the
1744 * parent and rate and sets them both.
1746 int __clk_init(struct device *dev, struct clk *clk)
1750 struct hlist_node *tmp2;
1757 /* check to see if a clock with this name is already registered */
1758 if (__clk_lookup(clk->name)) {
1759 pr_debug("%s: clk %s already initialized\n",
1760 __func__, clk->name);
1765 /* check that clk_ops are sane. See Documentation/clk.txt */
1766 if (clk->ops->set_rate &&
1767 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1768 clk->ops->recalc_rate)) {
1769 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1770 __func__, clk->name);
1775 if (clk->ops->set_parent && !clk->ops->get_parent) {
1776 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1777 __func__, clk->name);
1782 if (clk->ops->set_rate_and_parent &&
1783 !(clk->ops->set_parent && clk->ops->set_rate)) {
1784 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
1785 __func__, clk->name);
1790 /* throw a WARN if any entries in parent_names are NULL */
1791 for (i = 0; i < clk->num_parents; i++)
1792 WARN(!clk->parent_names[i],
1793 "%s: invalid NULL in %s's .parent_names\n",
1794 __func__, clk->name);
1797 * Allocate an array of struct clk *'s to avoid unnecessary string
1798 * look-ups of clk's possible parents. This can fail for clocks passed
1799 * in to clk_init during early boot; thus any access to clk->parents[]
1800 * must always check for a NULL pointer and try to populate it if
1803 * If clk->parents is not NULL we skip this entire block. This allows
1804 * for clock drivers to statically initialize clk->parents.
1806 if (clk->num_parents > 1 && !clk->parents) {
1807 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
1810 * __clk_lookup returns NULL for parents that have not been
1811 * clk_init'd; thus any access to clk->parents[] must check
1812 * for a NULL pointer. We can always perform lazy lookups for
1813 * missing parents later on.
1816 for (i = 0; i < clk->num_parents; i++)
1818 __clk_lookup(clk->parent_names[i]);
1821 clk->parent = __clk_init_parent(clk);
1824 * Populate clk->parent if parent has already been __clk_init'd. If
1825 * parent has not yet been __clk_init'd then place clk in the orphan
1826 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1829 * Every time a new clk is clk_init'd then we walk the list of orphan
1830 * clocks and re-parent any that are children of the clock currently
1834 hlist_add_head(&clk->child_node,
1835 &clk->parent->children);
1836 else if (clk->flags & CLK_IS_ROOT)
1837 hlist_add_head(&clk->child_node, &clk_root_list);
1839 hlist_add_head(&clk->child_node, &clk_orphan_list);
1842 * Set clk's accuracy. The preferred method is to use
1843 * .recalc_accuracy. For simple clocks and lazy developers the default
1844 * fallback is to use the parent's accuracy. If a clock doesn't have a
1845 * parent (or is orphaned) then accuracy is set to zero (perfect
1848 if (clk->ops->recalc_accuracy)
1849 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1850 __clk_get_accuracy(clk->parent));
1851 else if (clk->parent)
1852 clk->accuracy = clk->parent->accuracy;
1857 * Set clk's rate. The preferred method is to use .recalc_rate. For
1858 * simple clocks and lazy developers the default fallback is to use the
1859 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1860 * then rate is set to zero.
1862 if (clk->ops->recalc_rate)
1863 clk->rate = clk->ops->recalc_rate(clk->hw,
1864 __clk_get_rate(clk->parent));
1865 else if (clk->parent)
1866 clk->rate = clk->parent->rate;
1870 clk_debug_register(clk);
1872 * walk the list of orphan clocks and reparent any that are children of
1875 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1876 if (orphan->num_parents && orphan->ops->get_parent) {
1877 i = orphan->ops->get_parent(orphan->hw);
1878 if (!strcmp(clk->name, orphan->parent_names[i]))
1879 __clk_reparent(orphan, clk);
1883 for (i = 0; i < orphan->num_parents; i++)
1884 if (!strcmp(clk->name, orphan->parent_names[i])) {
1885 __clk_reparent(orphan, clk);
1891 * optional platform-specific magic
1893 * The .init callback is not used by any of the basic clock types, but
1894 * exists for weird hardware that must perform initialization magic.
1895 * Please consider other ways of solving initialization problems before
1896 * using this callback, as its use is discouraged.
1899 clk->ops->init(clk->hw);
1901 kref_init(&clk->ref);
1903 clk_prepare_unlock();
1909 * __clk_register - register a clock and return a cookie.
1911 * Same as clk_register, except that the .clk field inside hw shall point to a
1912 * preallocated (generally statically allocated) struct clk. None of the fields
1913 * of the struct clk need to be initialized.
1915 * The data pointed to by .init and .clk field shall NOT be marked as init
1918 * __clk_register is only exposed via clk-private.h and is intended for use with
1919 * very large numbers of clocks that need to be statically initialized. It is
1920 * a layering violation to include clk-private.h from any code which implements
1921 * a clock's .ops; as such any statically initialized clock data MUST be in a
1922 * separate C file from the logic that implements its operations. Returns 0
1923 * on success, otherwise an error code.
1925 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1931 clk->name = hw->init->name;
1932 clk->ops = hw->init->ops;
1934 clk->flags = hw->init->flags;
1935 clk->parent_names = hw->init->parent_names;
1936 clk->num_parents = hw->init->num_parents;
1937 if (dev && dev->driver)
1938 clk->owner = dev->driver->owner;
1942 ret = __clk_init(dev, clk);
1944 return ERR_PTR(ret);
1948 EXPORT_SYMBOL_GPL(__clk_register);
1951 * clk_register - allocate a new clock, register it and return an opaque cookie
1952 * @dev: device that is registering this clock
1953 * @hw: link to hardware-specific clock data
1955 * clk_register is the primary interface for populating the clock tree with new
1956 * clock nodes. It returns a pointer to the newly allocated struct clk which
1957 * cannot be dereferenced by driver code but may be used in conjuction with the
1958 * rest of the clock API. In the event of an error clk_register will return an
1959 * error code; drivers must test for an error code after calling clk_register.
1961 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1966 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1968 pr_err("%s: could not allocate clk\n", __func__);
1973 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1975 pr_err("%s: could not allocate clk->name\n", __func__);
1979 clk->ops = hw->init->ops;
1980 if (dev && dev->driver)
1981 clk->owner = dev->driver->owner;
1983 clk->flags = hw->init->flags;
1984 clk->num_parents = hw->init->num_parents;
1987 /* allocate local copy in case parent_names is __initdata */
1988 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
1991 if (!clk->parent_names) {
1992 pr_err("%s: could not allocate clk->parent_names\n", __func__);
1994 goto fail_parent_names;
1998 /* copy each string name in case parent_names is __initdata */
1999 for (i = 0; i < clk->num_parents; i++) {
2000 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
2002 if (!clk->parent_names[i]) {
2003 pr_err("%s: could not copy parent_names\n", __func__);
2005 goto fail_parent_names_copy;
2009 ret = __clk_init(dev, clk);
2013 fail_parent_names_copy:
2015 kfree(clk->parent_names[i]);
2016 kfree(clk->parent_names);
2022 return ERR_PTR(ret);
2024 EXPORT_SYMBOL_GPL(clk_register);
2027 * Free memory allocated for a clock.
2028 * Caller must hold prepare_lock.
2030 static void __clk_release(struct kref *ref)
2032 struct clk *clk = container_of(ref, struct clk, ref);
2033 int i = clk->num_parents;
2035 kfree(clk->parents);
2037 kfree(clk->parent_names[i]);
2039 kfree(clk->parent_names);
2045 * Empty clk_ops for unregistered clocks. These are used temporarily
2046 * after clk_unregister() was called on a clock and until last clock
2047 * consumer calls clk_put() and the struct clk object is freed.
2049 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2054 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2059 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2060 unsigned long parent_rate)
2065 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2070 static const struct clk_ops clk_nodrv_ops = {
2071 .enable = clk_nodrv_prepare_enable,
2072 .disable = clk_nodrv_disable_unprepare,
2073 .prepare = clk_nodrv_prepare_enable,
2074 .unprepare = clk_nodrv_disable_unprepare,
2075 .set_rate = clk_nodrv_set_rate,
2076 .set_parent = clk_nodrv_set_parent,
2080 * clk_unregister - unregister a currently registered clock
2081 * @clk: clock to unregister
2083 void clk_unregister(struct clk *clk)
2085 unsigned long flags;
2087 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2092 if (clk->ops == &clk_nodrv_ops) {
2093 pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
2097 * Assign empty clock ops for consumers that might still hold
2098 * a reference to this clock.
2100 flags = clk_enable_lock();
2101 clk->ops = &clk_nodrv_ops;
2102 clk_enable_unlock(flags);
2104 if (!hlist_empty(&clk->children)) {
2106 struct hlist_node *t;
2108 /* Reparent all children to the orphan list. */
2109 hlist_for_each_entry_safe(child, t, &clk->children, child_node)
2110 clk_set_parent(child, NULL);
2113 clk_debug_unregister(clk);
2115 hlist_del_init(&clk->child_node);
2117 if (clk->prepare_count)
2118 pr_warn("%s: unregistering prepared clock: %s\n",
2119 __func__, clk->name);
2121 kref_put(&clk->ref, __clk_release);
2123 clk_prepare_unlock();
2125 EXPORT_SYMBOL_GPL(clk_unregister);
2127 static void devm_clk_release(struct device *dev, void *res)
2129 clk_unregister(*(struct clk **)res);
2133 * devm_clk_register - resource managed clk_register()
2134 * @dev: device that is registering this clock
2135 * @hw: link to hardware-specific clock data
2137 * Managed clk_register(). Clocks returned from this function are
2138 * automatically clk_unregister()ed on driver detach. See clk_register() for
2141 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2146 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2148 return ERR_PTR(-ENOMEM);
2150 clk = clk_register(dev, hw);
2153 devres_add(dev, clkp);
2160 EXPORT_SYMBOL_GPL(devm_clk_register);
2162 static int devm_clk_match(struct device *dev, void *res, void *data)
2164 struct clk *c = res;
2171 * devm_clk_unregister - resource managed clk_unregister()
2172 * @clk: clock to unregister
2174 * Deallocate a clock allocated with devm_clk_register(). Normally
2175 * this function will not need to be called and the resource management
2176 * code will ensure that the resource is freed.
2178 void devm_clk_unregister(struct device *dev, struct clk *clk)
2180 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2182 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2187 int __clk_get(struct clk *clk)
2190 if (!try_module_get(clk->owner))
2193 kref_get(&clk->ref);
2198 void __clk_put(struct clk *clk)
2200 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2204 kref_put(&clk->ref, __clk_release);
2205 clk_prepare_unlock();
2207 module_put(clk->owner);
2210 /*** clk rate change notifiers ***/
2213 * clk_notifier_register - add a clk rate change notifier
2214 * @clk: struct clk * to watch
2215 * @nb: struct notifier_block * with callback info
2217 * Request notification when clk's rate changes. This uses an SRCU
2218 * notifier because we want it to block and notifier unregistrations are
2219 * uncommon. The callbacks associated with the notifier must not
2220 * re-enter into the clk framework by calling any top-level clk APIs;
2221 * this will cause a nested prepare_lock mutex.
2223 * In all notification cases cases (pre, post and abort rate change) the
2224 * original clock rate is passed to the callback via struct
2225 * clk_notifier_data.old_rate and the new frequency is passed via struct
2226 * clk_notifier_data.new_rate.
2228 * clk_notifier_register() must be called from non-atomic context.
2229 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2230 * allocation failure; otherwise, passes along the return value of
2231 * srcu_notifier_chain_register().
2233 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2235 struct clk_notifier *cn;
2243 /* search the list of notifiers for this clk */
2244 list_for_each_entry(cn, &clk_notifier_list, node)
2248 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2249 if (cn->clk != clk) {
2250 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2255 srcu_init_notifier_head(&cn->notifier_head);
2257 list_add(&cn->node, &clk_notifier_list);
2260 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2262 clk->notifier_count++;
2265 clk_prepare_unlock();
2269 EXPORT_SYMBOL_GPL(clk_notifier_register);
2272 * clk_notifier_unregister - remove a clk rate change notifier
2273 * @clk: struct clk *
2274 * @nb: struct notifier_block * with callback info
2276 * Request no further notification for changes to 'clk' and frees memory
2277 * allocated in clk_notifier_register.
2279 * Returns -EINVAL if called with null arguments; otherwise, passes
2280 * along the return value of srcu_notifier_chain_unregister().
2282 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2284 struct clk_notifier *cn = NULL;
2292 list_for_each_entry(cn, &clk_notifier_list, node)
2296 if (cn->clk == clk) {
2297 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2299 clk->notifier_count--;
2301 /* XXX the notifier code should handle this better */
2302 if (!cn->notifier_head.head) {
2303 srcu_cleanup_notifier_head(&cn->notifier_head);
2304 list_del(&cn->node);
2312 clk_prepare_unlock();
2316 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2320 * struct of_clk_provider - Clock provider registration structure
2321 * @link: Entry in global list of clock providers
2322 * @node: Pointer to device tree node of clock provider
2323 * @get: Get clock callback. Returns NULL or a struct clk for the
2324 * given clock specifier
2325 * @data: context pointer to be passed into @get callback
2327 struct of_clk_provider {
2328 struct list_head link;
2330 struct device_node *node;
2331 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2335 static const struct of_device_id __clk_of_table_sentinel
2336 __used __section(__clk_of_table_end);
2338 static LIST_HEAD(of_clk_providers);
2339 static DEFINE_MUTEX(of_clk_mutex);
2341 /* of_clk_provider list locking helpers */
2342 void of_clk_lock(void)
2344 mutex_lock(&of_clk_mutex);
2347 void of_clk_unlock(void)
2349 mutex_unlock(&of_clk_mutex);
2352 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2357 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2359 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2361 struct clk_onecell_data *clk_data = data;
2362 unsigned int idx = clkspec->args[0];
2364 if (idx >= clk_data->clk_num) {
2365 pr_err("%s: invalid clock index %d\n", __func__, idx);
2366 return ERR_PTR(-EINVAL);
2369 return clk_data->clks[idx];
2371 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2374 * of_clk_add_provider() - Register a clock provider for a node
2375 * @np: Device node pointer associated with clock provider
2376 * @clk_src_get: callback for decoding clock
2377 * @data: context pointer for @clk_src_get callback.
2379 int of_clk_add_provider(struct device_node *np,
2380 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2384 struct of_clk_provider *cp;
2386 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2390 cp->node = of_node_get(np);
2392 cp->get = clk_src_get;
2394 mutex_lock(&of_clk_mutex);
2395 list_add(&cp->link, &of_clk_providers);
2396 mutex_unlock(&of_clk_mutex);
2397 pr_debug("Added clock from %s\n", np->full_name);
2401 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2404 * of_clk_del_provider() - Remove a previously registered clock provider
2405 * @np: Device node pointer associated with clock provider
2407 void of_clk_del_provider(struct device_node *np)
2409 struct of_clk_provider *cp;
2411 mutex_lock(&of_clk_mutex);
2412 list_for_each_entry(cp, &of_clk_providers, link) {
2413 if (cp->node == np) {
2414 list_del(&cp->link);
2415 of_node_put(cp->node);
2420 mutex_unlock(&of_clk_mutex);
2422 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2424 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec)
2426 struct of_clk_provider *provider;
2427 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2429 /* Check if we have such a provider in our array */
2430 list_for_each_entry(provider, &of_clk_providers, link) {
2431 if (provider->node == clkspec->np)
2432 clk = provider->get(clkspec, provider->data);
2440 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2444 mutex_lock(&of_clk_mutex);
2445 clk = __of_clk_get_from_provider(clkspec);
2446 mutex_unlock(&of_clk_mutex);
2451 int of_clk_get_parent_count(struct device_node *np)
2453 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2455 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2457 const char *of_clk_get_parent_name(struct device_node *np, int index)
2459 struct of_phandle_args clkspec;
2460 struct property *prop;
2461 const char *clk_name;
2470 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2475 index = clkspec.args_count ? clkspec.args[0] : 0;
2478 /* if there is an indices property, use it to transfer the index
2479 * specified into an array offset for the clock-output-names property.
2481 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
2489 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2492 clk_name = clkspec.np->name;
2494 of_node_put(clkspec.np);
2497 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2499 struct clock_provider {
2500 of_clk_init_cb_t clk_init_cb;
2501 struct device_node *np;
2502 struct list_head node;
2505 static LIST_HEAD(clk_provider_list);
2508 * This function looks for a parent clock. If there is one, then it
2509 * checks that the provider for this parent clock was initialized, in
2510 * this case the parent clock will be ready.
2512 static int parent_ready(struct device_node *np)
2517 struct clk *clk = of_clk_get(np, i);
2519 /* this parent is ready we can check the next one */
2526 /* at least one parent is not ready, we exit now */
2527 if (PTR_ERR(clk) == -EPROBE_DEFER)
2531 * Here we make assumption that the device tree is
2532 * written correctly. So an error means that there is
2533 * no more parent. As we didn't exit yet, then the
2534 * previous parent are ready. If there is no clock
2535 * parent, no need to wait for them, then we can
2536 * consider their absence as being ready
2543 * of_clk_init() - Scan and init clock providers from the DT
2544 * @matches: array of compatible values and init functions for providers.
2546 * This function scans the device tree for matching clock providers
2547 * and calls their initialization functions. It also does it by trying
2548 * to follow the dependencies.
2550 void __init of_clk_init(const struct of_device_id *matches)
2552 const struct of_device_id *match;
2553 struct device_node *np;
2554 struct clock_provider *clk_provider, *next;
2559 matches = &__clk_of_table;
2561 /* First prepare the list of the clocks providers */
2562 for_each_matching_node_and_match(np, matches, &match) {
2563 struct clock_provider *parent =
2564 kzalloc(sizeof(struct clock_provider), GFP_KERNEL);
2566 parent->clk_init_cb = match->data;
2568 list_add_tail(&parent->node, &clk_provider_list);
2571 while (!list_empty(&clk_provider_list)) {
2572 is_init_done = false;
2573 list_for_each_entry_safe(clk_provider, next,
2574 &clk_provider_list, node) {
2575 if (force || parent_ready(clk_provider->np)) {
2576 clk_provider->clk_init_cb(clk_provider->np);
2577 list_del(&clk_provider->node);
2578 kfree(clk_provider);
2579 is_init_done = true;
2584 * We didn't manage to initialize any of the
2585 * remaining providers during the last loop, so now we
2586 * initialize all the remaining ones unconditionally
2587 * in case the clock parent was not mandatory