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/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);
41 static void clk_prepare_lock(void)
43 if (!mutex_trylock(&prepare_lock)) {
44 if (prepare_owner == current) {
48 mutex_lock(&prepare_lock);
50 WARN_ON_ONCE(prepare_owner != NULL);
51 WARN_ON_ONCE(prepare_refcnt != 0);
52 prepare_owner = current;
56 static void clk_prepare_unlock(void)
58 WARN_ON_ONCE(prepare_owner != current);
59 WARN_ON_ONCE(prepare_refcnt == 0);
64 mutex_unlock(&prepare_lock);
67 static unsigned long clk_enable_lock(void)
71 if (!spin_trylock_irqsave(&enable_lock, flags)) {
72 if (enable_owner == current) {
76 spin_lock_irqsave(&enable_lock, flags);
78 WARN_ON_ONCE(enable_owner != NULL);
79 WARN_ON_ONCE(enable_refcnt != 0);
80 enable_owner = current;
85 static void clk_enable_unlock(unsigned long flags)
87 WARN_ON_ONCE(enable_owner != current);
88 WARN_ON_ONCE(enable_refcnt == 0);
93 spin_unlock_irqrestore(&enable_lock, flags);
96 /*** debugfs support ***/
98 #ifdef CONFIG_DEBUG_FS
99 #include <linux/debugfs.h>
101 static struct dentry *rootdir;
102 static int inited = 0;
104 static struct hlist_head *all_lists[] = {
110 static struct hlist_head *orphan_list[] = {
115 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
120 seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
122 30 - level * 3, c->name,
123 c->enable_count, c->prepare_count, clk_get_rate(c),
124 clk_get_accuracy(c), clk_get_phase(c));
127 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
135 clk_summary_show_one(s, c, level);
137 hlist_for_each_entry(child, &c->children, child_node)
138 clk_summary_show_subtree(s, child, level + 1);
141 static int clk_summary_show(struct seq_file *s, void *data)
144 struct hlist_head **lists = (struct hlist_head **)s->private;
146 seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy phase\n");
147 seq_puts(s, "----------------------------------------------------------------------------------------\n");
151 for (; *lists; lists++)
152 hlist_for_each_entry(c, *lists, child_node)
153 clk_summary_show_subtree(s, c, 0);
155 clk_prepare_unlock();
161 static int clk_summary_open(struct inode *inode, struct file *file)
163 return single_open(file, clk_summary_show, inode->i_private);
166 static const struct file_operations clk_summary_fops = {
167 .open = clk_summary_open,
170 .release = single_release,
173 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
178 seq_printf(s, "\"%s\": { ", c->name);
179 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
180 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
181 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
182 seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
183 seq_printf(s, "\"phase\": %d", clk_get_phase(c));
186 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
193 clk_dump_one(s, c, level);
195 hlist_for_each_entry(child, &c->children, child_node) {
197 clk_dump_subtree(s, child, level + 1);
203 static int clk_dump(struct seq_file *s, void *data)
206 bool first_node = true;
207 struct hlist_head **lists = (struct hlist_head **)s->private;
213 for (; *lists; lists++) {
214 hlist_for_each_entry(c, *lists, child_node) {
218 clk_dump_subtree(s, c, 0);
222 clk_prepare_unlock();
229 static int clk_dump_open(struct inode *inode, struct file *file)
231 return single_open(file, clk_dump, inode->i_private);
234 static const struct file_operations clk_dump_fops = {
235 .open = clk_dump_open,
238 .release = single_release,
241 /* caller must hold prepare_lock */
242 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
247 if (!clk || !pdentry) {
252 d = debugfs_create_dir(clk->name, pdentry);
258 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
263 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
264 (u32 *)&clk->accuracy);
268 d = debugfs_create_u32("clk_phase", S_IRUGO, clk->dentry,
273 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
278 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
279 (u32 *)&clk->prepare_count);
283 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
284 (u32 *)&clk->enable_count);
288 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
289 (u32 *)&clk->notifier_count);
293 if (clk->ops->debug_init) {
294 ret = clk->ops->debug_init(clk->hw, clk->dentry);
303 debugfs_remove_recursive(clk->dentry);
309 /* caller must hold prepare_lock */
310 static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
315 if (!clk || !pdentry)
318 ret = clk_debug_create_one(clk, pdentry);
323 hlist_for_each_entry(child, &clk->children, child_node)
324 clk_debug_create_subtree(child, pdentry);
332 * clk_debug_register - add a clk node to the debugfs clk tree
333 * @clk: the clk being added to the debugfs clk tree
335 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
336 * initialized. Otherwise it bails out early since the debugfs clk tree
337 * will be created lazily by clk_debug_init as part of a late_initcall.
339 * Caller must hold prepare_lock. Only clk_init calls this function (so
340 * far) so this is taken care.
342 static int clk_debug_register(struct clk *clk)
349 ret = clk_debug_create_subtree(clk, rootdir);
356 * clk_debug_unregister - remove a clk node from the debugfs clk tree
357 * @clk: the clk being removed from the debugfs clk tree
359 * Dynamically removes a clk and all it's children clk nodes from the
360 * debugfs clk tree if clk->dentry points to debugfs created by
361 * clk_debug_register in __clk_init.
363 * Caller must hold prepare_lock.
365 static void clk_debug_unregister(struct clk *clk)
367 debugfs_remove_recursive(clk->dentry);
370 struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
371 void *data, const struct file_operations *fops)
373 struct dentry *d = NULL;
376 d = debugfs_create_file(name, mode, clk->dentry, data, fops);
380 EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
383 * clk_debug_init - lazily create the debugfs clk tree visualization
385 * clks are often initialized very early during boot before memory can
386 * be dynamically allocated and well before debugfs is setup.
387 * clk_debug_init walks the clk tree hierarchy while holding
388 * prepare_lock and creates the topology as part of a late_initcall,
389 * thus insuring that clks initialized very early will still be
390 * represented in the debugfs clk tree. This function should only be
391 * called once at boot-time, and all other clks added dynamically will
392 * be done so with clk_debug_register.
394 static int __init clk_debug_init(void)
399 rootdir = debugfs_create_dir("clk", NULL);
404 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists,
409 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists,
414 d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir,
415 &orphan_list, &clk_summary_fops);
419 d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir,
420 &orphan_list, &clk_dump_fops);
426 hlist_for_each_entry(clk, &clk_root_list, child_node)
427 clk_debug_create_subtree(clk, rootdir);
429 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
430 clk_debug_create_subtree(clk, rootdir);
434 clk_prepare_unlock();
438 late_initcall(clk_debug_init);
440 static inline int clk_debug_register(struct clk *clk) { return 0; }
441 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
444 static inline void clk_debug_unregister(struct clk *clk)
449 /* caller must hold prepare_lock */
450 static void clk_unprepare_unused_subtree(struct clk *clk)
457 hlist_for_each_entry(child, &clk->children, child_node)
458 clk_unprepare_unused_subtree(child);
460 if (clk->prepare_count)
463 if (clk->flags & CLK_IGNORE_UNUSED)
466 if (__clk_is_prepared(clk)) {
467 if (clk->ops->unprepare_unused)
468 clk->ops->unprepare_unused(clk->hw);
469 else if (clk->ops->unprepare)
470 clk->ops->unprepare(clk->hw);
474 /* caller must hold prepare_lock */
475 static void clk_disable_unused_subtree(struct clk *clk)
483 hlist_for_each_entry(child, &clk->children, child_node)
484 clk_disable_unused_subtree(child);
486 flags = clk_enable_lock();
488 if (clk->enable_count)
491 if (clk->flags & CLK_IGNORE_UNUSED)
495 * some gate clocks have special needs during the disable-unused
496 * sequence. call .disable_unused if available, otherwise fall
499 if (__clk_is_enabled(clk)) {
500 if (clk->ops->disable_unused)
501 clk->ops->disable_unused(clk->hw);
502 else if (clk->ops->disable)
503 clk->ops->disable(clk->hw);
507 clk_enable_unlock(flags);
513 static bool clk_ignore_unused;
514 static int __init clk_ignore_unused_setup(char *__unused)
516 clk_ignore_unused = true;
519 __setup("clk_ignore_unused", clk_ignore_unused_setup);
521 static int clk_disable_unused(void)
525 if (clk_ignore_unused) {
526 pr_warn("clk: Not disabling unused clocks\n");
532 hlist_for_each_entry(clk, &clk_root_list, child_node)
533 clk_disable_unused_subtree(clk);
535 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
536 clk_disable_unused_subtree(clk);
538 hlist_for_each_entry(clk, &clk_root_list, child_node)
539 clk_unprepare_unused_subtree(clk);
541 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
542 clk_unprepare_unused_subtree(clk);
544 clk_prepare_unlock();
548 late_initcall_sync(clk_disable_unused);
550 /*** helper functions ***/
552 const char *__clk_get_name(struct clk *clk)
554 return !clk ? NULL : clk->name;
556 EXPORT_SYMBOL_GPL(__clk_get_name);
558 struct clk_hw *__clk_get_hw(struct clk *clk)
560 return !clk ? NULL : clk->hw;
562 EXPORT_SYMBOL_GPL(__clk_get_hw);
564 u8 __clk_get_num_parents(struct clk *clk)
566 return !clk ? 0 : clk->num_parents;
568 EXPORT_SYMBOL_GPL(__clk_get_num_parents);
570 struct clk *__clk_get_parent(struct clk *clk)
572 return !clk ? NULL : clk->parent;
574 EXPORT_SYMBOL_GPL(__clk_get_parent);
576 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
578 if (!clk || index >= clk->num_parents)
580 else if (!clk->parents)
581 return __clk_lookup(clk->parent_names[index]);
582 else if (!clk->parents[index])
583 return clk->parents[index] =
584 __clk_lookup(clk->parent_names[index]);
586 return clk->parents[index];
588 EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
590 unsigned int __clk_get_enable_count(struct clk *clk)
592 return !clk ? 0 : clk->enable_count;
595 unsigned int __clk_get_prepare_count(struct clk *clk)
597 return !clk ? 0 : clk->prepare_count;
600 unsigned long __clk_get_rate(struct clk *clk)
611 if (clk->flags & CLK_IS_ROOT)
620 EXPORT_SYMBOL_GPL(__clk_get_rate);
622 unsigned long __clk_get_accuracy(struct clk *clk)
627 return clk->accuracy;
630 unsigned long __clk_get_flags(struct clk *clk)
632 return !clk ? 0 : clk->flags;
634 EXPORT_SYMBOL_GPL(__clk_get_flags);
636 bool __clk_is_prepared(struct clk *clk)
644 * .is_prepared is optional for clocks that can prepare
645 * fall back to software usage counter if it is missing
647 if (!clk->ops->is_prepared) {
648 ret = clk->prepare_count ? 1 : 0;
652 ret = clk->ops->is_prepared(clk->hw);
657 bool __clk_is_enabled(struct clk *clk)
665 * .is_enabled is only mandatory for clocks that gate
666 * fall back to software usage counter if .is_enabled is missing
668 if (!clk->ops->is_enabled) {
669 ret = clk->enable_count ? 1 : 0;
673 ret = clk->ops->is_enabled(clk->hw);
677 EXPORT_SYMBOL_GPL(__clk_is_enabled);
679 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
684 if (!strcmp(clk->name, name))
687 hlist_for_each_entry(child, &clk->children, child_node) {
688 ret = __clk_lookup_subtree(name, child);
696 struct clk *__clk_lookup(const char *name)
698 struct clk *root_clk;
704 /* search the 'proper' clk tree first */
705 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
706 ret = __clk_lookup_subtree(name, root_clk);
711 /* if not found, then search the orphan tree */
712 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
713 ret = __clk_lookup_subtree(name, root_clk);
722 * Helper for finding best parent to provide a given frequency. This can be used
723 * directly as a determine_rate callback (e.g. for a mux), or from a more
724 * complex clock that may combine a mux with other operations.
726 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
727 unsigned long *best_parent_rate,
728 struct clk **best_parent_p)
730 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
732 unsigned long parent_rate, best = 0;
734 /* if NO_REPARENT flag set, pass through to current parent */
735 if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
736 parent = clk->parent;
737 if (clk->flags & CLK_SET_RATE_PARENT)
738 best = __clk_round_rate(parent, rate);
740 best = __clk_get_rate(parent);
742 best = __clk_get_rate(clk);
746 /* find the parent that can provide the fastest rate <= rate */
747 num_parents = clk->num_parents;
748 for (i = 0; i < num_parents; i++) {
749 parent = clk_get_parent_by_index(clk, i);
752 if (clk->flags & CLK_SET_RATE_PARENT)
753 parent_rate = __clk_round_rate(parent, rate);
755 parent_rate = __clk_get_rate(parent);
756 if (parent_rate <= rate && parent_rate > best) {
757 best_parent = parent;
764 *best_parent_p = best_parent;
765 *best_parent_rate = best;
769 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
773 void __clk_unprepare(struct clk *clk)
778 if (WARN_ON(clk->prepare_count == 0))
781 if (--clk->prepare_count > 0)
784 WARN_ON(clk->enable_count > 0);
786 if (clk->ops->unprepare)
787 clk->ops->unprepare(clk->hw);
789 __clk_unprepare(clk->parent);
793 * clk_unprepare - undo preparation of a clock source
794 * @clk: the clk being unprepared
796 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
797 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
798 * if the operation may sleep. One example is a clk which is accessed over
799 * I2c. In the complex case a clk gate operation may require a fast and a slow
800 * part. It is this reason that clk_unprepare and clk_disable are not mutually
801 * exclusive. In fact clk_disable must be called before clk_unprepare.
803 void clk_unprepare(struct clk *clk)
805 if (IS_ERR_OR_NULL(clk))
809 __clk_unprepare(clk);
810 clk_prepare_unlock();
812 EXPORT_SYMBOL_GPL(clk_unprepare);
814 int __clk_prepare(struct clk *clk)
821 if (clk->prepare_count == 0) {
822 ret = __clk_prepare(clk->parent);
826 if (clk->ops->prepare) {
827 ret = clk->ops->prepare(clk->hw);
829 __clk_unprepare(clk->parent);
835 clk->prepare_count++;
841 * clk_prepare - prepare a clock source
842 * @clk: the clk being prepared
844 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
845 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
846 * operation may sleep. One example is a clk which is accessed over I2c. In
847 * the complex case a clk ungate operation may require a fast and a slow part.
848 * It is this reason that clk_prepare and clk_enable are not mutually
849 * exclusive. In fact clk_prepare must be called before clk_enable.
850 * Returns 0 on success, -EERROR otherwise.
852 int clk_prepare(struct clk *clk)
857 ret = __clk_prepare(clk);
858 clk_prepare_unlock();
862 EXPORT_SYMBOL_GPL(clk_prepare);
864 static void __clk_disable(struct clk *clk)
869 if (WARN_ON(clk->enable_count == 0))
872 if (--clk->enable_count > 0)
875 if (clk->ops->disable)
876 clk->ops->disable(clk->hw);
878 __clk_disable(clk->parent);
882 * clk_disable - gate a clock
883 * @clk: the clk being gated
885 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
886 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
887 * clk if the operation is fast and will never sleep. One example is a
888 * SoC-internal clk which is controlled via simple register writes. In the
889 * complex case a clk gate operation may require a fast and a slow part. It is
890 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
891 * In fact clk_disable must be called before clk_unprepare.
893 void clk_disable(struct clk *clk)
897 if (IS_ERR_OR_NULL(clk))
900 flags = clk_enable_lock();
902 clk_enable_unlock(flags);
904 EXPORT_SYMBOL_GPL(clk_disable);
906 static int __clk_enable(struct clk *clk)
913 if (WARN_ON(clk->prepare_count == 0))
916 if (clk->enable_count == 0) {
917 ret = __clk_enable(clk->parent);
922 if (clk->ops->enable) {
923 ret = clk->ops->enable(clk->hw);
925 __clk_disable(clk->parent);
936 * clk_enable - ungate a clock
937 * @clk: the clk being ungated
939 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
940 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
941 * if the operation will never sleep. One example is a SoC-internal clk which
942 * is controlled via simple register writes. In the complex case a clk ungate
943 * operation may require a fast and a slow part. It is this reason that
944 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
945 * must be called before clk_enable. Returns 0 on success, -EERROR
948 int clk_enable(struct clk *clk)
953 flags = clk_enable_lock();
954 ret = __clk_enable(clk);
955 clk_enable_unlock(flags);
959 EXPORT_SYMBOL_GPL(clk_enable);
962 * __clk_round_rate - round the given rate for a clk
963 * @clk: round the rate of this clock
964 * @rate: the rate which is to be rounded
966 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
968 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
970 unsigned long parent_rate = 0;
976 parent = clk->parent;
978 parent_rate = parent->rate;
980 if (clk->ops->determine_rate)
981 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
983 else if (clk->ops->round_rate)
984 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
985 else if (clk->flags & CLK_SET_RATE_PARENT)
986 return __clk_round_rate(clk->parent, rate);
990 EXPORT_SYMBOL_GPL(__clk_round_rate);
993 * clk_round_rate - round the given rate for a clk
994 * @clk: the clk for which we are rounding a rate
995 * @rate: the rate which is to be rounded
997 * Takes in a rate as input and rounds it to a rate that the clk can actually
998 * use which is then returned. If clk doesn't support round_rate operation
999 * then the parent rate is returned.
1001 long clk_round_rate(struct clk *clk, unsigned long rate)
1006 ret = __clk_round_rate(clk, rate);
1007 clk_prepare_unlock();
1011 EXPORT_SYMBOL_GPL(clk_round_rate);
1014 * __clk_notify - call clk notifier chain
1015 * @clk: struct clk * that is changing rate
1016 * @msg: clk notifier type (see include/linux/clk.h)
1017 * @old_rate: old clk rate
1018 * @new_rate: new clk rate
1020 * Triggers a notifier call chain on the clk rate-change notification
1021 * for 'clk'. Passes a pointer to the struct clk and the previous
1022 * and current rates to the notifier callback. Intended to be called by
1023 * internal clock code only. Returns NOTIFY_DONE from the last driver
1024 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1025 * a driver returns that.
1027 static int __clk_notify(struct clk *clk, unsigned long msg,
1028 unsigned long old_rate, unsigned long new_rate)
1030 struct clk_notifier *cn;
1031 struct clk_notifier_data cnd;
1032 int ret = NOTIFY_DONE;
1035 cnd.old_rate = old_rate;
1036 cnd.new_rate = new_rate;
1038 list_for_each_entry(cn, &clk_notifier_list, node) {
1039 if (cn->clk == clk) {
1040 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1050 * __clk_recalc_accuracies
1051 * @clk: first clk in the subtree
1053 * Walks the subtree of clks starting with clk and recalculates accuracies as
1054 * it goes. Note that if a clk does not implement the .recalc_accuracy
1055 * callback then it is assumed that the clock will take on the accuracy of it's
1058 * Caller must hold prepare_lock.
1060 static void __clk_recalc_accuracies(struct clk *clk)
1062 unsigned long parent_accuracy = 0;
1066 parent_accuracy = clk->parent->accuracy;
1068 if (clk->ops->recalc_accuracy)
1069 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1072 clk->accuracy = parent_accuracy;
1074 hlist_for_each_entry(child, &clk->children, child_node)
1075 __clk_recalc_accuracies(child);
1079 * clk_get_accuracy - return the accuracy of clk
1080 * @clk: the clk whose accuracy is being returned
1082 * Simply returns the cached accuracy of the clk, unless
1083 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1085 * If clk is NULL then returns 0.
1087 long clk_get_accuracy(struct clk *clk)
1089 unsigned long accuracy;
1092 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1093 __clk_recalc_accuracies(clk);
1095 accuracy = __clk_get_accuracy(clk);
1096 clk_prepare_unlock();
1100 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1102 static unsigned long clk_recalc(struct clk *clk, unsigned long parent_rate)
1104 if (clk->ops->recalc_rate)
1105 return clk->ops->recalc_rate(clk->hw, parent_rate);
1110 * __clk_recalc_rates
1111 * @clk: first clk in the subtree
1112 * @msg: notification type (see include/linux/clk.h)
1114 * Walks the subtree of clks starting with clk and recalculates rates as it
1115 * goes. Note that if a clk does not implement the .recalc_rate callback then
1116 * it is assumed that the clock will take on the rate of its parent.
1118 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1121 * Caller must hold prepare_lock.
1123 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
1125 unsigned long old_rate;
1126 unsigned long parent_rate = 0;
1129 old_rate = clk->rate;
1132 parent_rate = clk->parent->rate;
1134 clk->rate = clk_recalc(clk, parent_rate);
1137 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1138 * & ABORT_RATE_CHANGE notifiers
1140 if (clk->notifier_count && msg)
1141 __clk_notify(clk, msg, old_rate, clk->rate);
1143 hlist_for_each_entry(child, &clk->children, child_node)
1144 __clk_recalc_rates(child, msg);
1148 * clk_get_rate - return the rate of clk
1149 * @clk: the clk whose rate is being returned
1151 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1152 * is set, which means a recalc_rate will be issued.
1153 * If clk is NULL then returns 0.
1155 unsigned long clk_get_rate(struct clk *clk)
1161 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1162 __clk_recalc_rates(clk, 0);
1164 rate = __clk_get_rate(clk);
1165 clk_prepare_unlock();
1169 EXPORT_SYMBOL_GPL(clk_get_rate);
1171 static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1175 if (!clk->parents) {
1176 clk->parents = kcalloc(clk->num_parents,
1177 sizeof(struct clk *), GFP_KERNEL);
1183 * find index of new parent clock using cached parent ptrs,
1184 * or if not yet cached, use string name comparison and cache
1185 * them now to avoid future calls to __clk_lookup.
1187 for (i = 0; i < clk->num_parents; i++) {
1188 if (clk->parents[i] == parent)
1191 if (clk->parents[i])
1194 if (!strcmp(clk->parent_names[i], parent->name)) {
1195 clk->parents[i] = __clk_lookup(parent->name);
1203 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1205 hlist_del(&clk->child_node);
1208 /* avoid duplicate POST_RATE_CHANGE notifications */
1209 if (new_parent->new_child == clk)
1210 new_parent->new_child = NULL;
1212 hlist_add_head(&clk->child_node, &new_parent->children);
1214 hlist_add_head(&clk->child_node, &clk_orphan_list);
1217 clk->parent = new_parent;
1220 static struct clk *__clk_set_parent_before(struct clk *clk, struct clk *parent)
1222 unsigned long flags;
1223 struct clk *old_parent = clk->parent;
1226 * Migrate prepare state between parents and prevent race with
1229 * If the clock is not prepared, then a race with
1230 * clk_enable/disable() is impossible since we already have the
1231 * prepare lock (future calls to clk_enable() need to be preceded by
1234 * If the clock is prepared, migrate the prepared state to the new
1235 * parent and also protect against a race with clk_enable() by
1236 * forcing the clock and the new parent on. This ensures that all
1237 * future calls to clk_enable() are practically NOPs with respect to
1238 * hardware and software states.
1240 * See also: Comment for clk_set_parent() below.
1242 if (clk->prepare_count) {
1243 __clk_prepare(parent);
1248 /* update the clk tree topology */
1249 flags = clk_enable_lock();
1250 clk_reparent(clk, parent);
1251 clk_enable_unlock(flags);
1256 static void __clk_set_parent_after(struct clk *clk, struct clk *parent,
1257 struct clk *old_parent)
1260 * Finish the migration of prepare state and undo the changes done
1261 * for preventing a race with clk_enable().
1263 if (clk->prepare_count) {
1265 clk_disable(old_parent);
1266 __clk_unprepare(old_parent);
1270 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1272 unsigned long flags;
1274 struct clk *old_parent;
1276 old_parent = __clk_set_parent_before(clk, parent);
1278 /* change clock input source */
1279 if (parent && clk->ops->set_parent)
1280 ret = clk->ops->set_parent(clk->hw, p_index);
1283 flags = clk_enable_lock();
1284 clk_reparent(clk, old_parent);
1285 clk_enable_unlock(flags);
1287 if (clk->prepare_count) {
1289 clk_disable(parent);
1290 __clk_unprepare(parent);
1295 __clk_set_parent_after(clk, parent, old_parent);
1301 * __clk_speculate_rates
1302 * @clk: first clk in the subtree
1303 * @parent_rate: the "future" rate of clk's parent
1305 * Walks the subtree of clks starting with clk, speculating rates as it
1306 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1308 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1309 * pre-rate change notifications and returns early if no clks in the
1310 * subtree have subscribed to the notifications. Note that if a clk does not
1311 * implement the .recalc_rate callback then it is assumed that the clock will
1312 * take on the rate of its parent.
1314 * Caller must hold prepare_lock.
1316 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1319 unsigned long new_rate;
1320 int ret = NOTIFY_DONE;
1322 new_rate = clk_recalc(clk, parent_rate);
1324 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1325 if (clk->notifier_count)
1326 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1328 if (ret & NOTIFY_STOP_MASK) {
1329 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1330 __func__, clk->name, ret);
1334 hlist_for_each_entry(child, &clk->children, child_node) {
1335 ret = __clk_speculate_rates(child, new_rate);
1336 if (ret & NOTIFY_STOP_MASK)
1344 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1345 struct clk *new_parent, u8 p_index)
1349 clk->new_rate = new_rate;
1350 clk->new_parent = new_parent;
1351 clk->new_parent_index = p_index;
1352 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1353 clk->new_child = NULL;
1354 if (new_parent && new_parent != clk->parent)
1355 new_parent->new_child = clk;
1357 hlist_for_each_entry(child, &clk->children, child_node) {
1358 child->new_rate = clk_recalc(child, new_rate);
1359 clk_calc_subtree(child, child->new_rate, NULL, 0);
1364 * calculate the new rates returning the topmost clock that has to be
1367 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1369 struct clk *top = clk;
1370 struct clk *old_parent, *parent;
1371 unsigned long best_parent_rate = 0;
1372 unsigned long new_rate;
1376 if (IS_ERR_OR_NULL(clk))
1379 /* save parent rate, if it exists */
1380 parent = old_parent = clk->parent;
1382 best_parent_rate = parent->rate;
1384 /* find the closest rate and parent clk/rate */
1385 if (clk->ops->determine_rate) {
1386 new_rate = clk->ops->determine_rate(clk->hw, rate,
1389 } else if (clk->ops->round_rate) {
1390 new_rate = clk->ops->round_rate(clk->hw, rate,
1392 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1393 /* pass-through clock without adjustable parent */
1394 clk->new_rate = clk->rate;
1397 /* pass-through clock with adjustable parent */
1398 top = clk_calc_new_rates(parent, rate);
1399 new_rate = parent->new_rate;
1403 /* some clocks must be gated to change parent */
1404 if (parent != old_parent &&
1405 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1406 pr_debug("%s: %s not gated but wants to reparent\n",
1407 __func__, clk->name);
1411 /* try finding the new parent index */
1413 p_index = clk_fetch_parent_index(clk, parent);
1415 pr_debug("%s: clk %s can not be parent of clk %s\n",
1416 __func__, parent->name, clk->name);
1421 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1422 best_parent_rate != parent->rate)
1423 top = clk_calc_new_rates(parent, best_parent_rate);
1426 clk_calc_subtree(clk, new_rate, parent, p_index);
1432 * Notify about rate changes in a subtree. Always walk down the whole tree
1433 * so that in case of an error we can walk down the whole tree again and
1436 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1438 struct clk *child, *tmp_clk, *fail_clk = NULL;
1439 int ret = NOTIFY_DONE;
1441 if (clk->rate == clk->new_rate)
1444 if (clk->notifier_count) {
1445 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1446 if (ret & NOTIFY_STOP_MASK)
1450 hlist_for_each_entry(child, &clk->children, child_node) {
1451 /* Skip children who will be reparented to another clock */
1452 if (child->new_parent && child->new_parent != clk)
1454 tmp_clk = clk_propagate_rate_change(child, event);
1459 /* handle the new child who might not be in clk->children yet */
1460 if (clk->new_child) {
1461 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1470 * walk down a subtree and set the new rates notifying the rate
1473 static void clk_change_rate(struct clk *clk)
1476 unsigned long old_rate;
1477 unsigned long best_parent_rate = 0;
1478 bool skip_set_rate = false;
1479 struct clk *old_parent;
1481 old_rate = clk->rate;
1483 if (clk->new_parent)
1484 best_parent_rate = clk->new_parent->rate;
1485 else if (clk->parent)
1486 best_parent_rate = clk->parent->rate;
1488 if (clk->new_parent && clk->new_parent != clk->parent) {
1489 old_parent = __clk_set_parent_before(clk, clk->new_parent);
1491 if (clk->ops->set_rate_and_parent) {
1492 skip_set_rate = true;
1493 clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
1495 clk->new_parent_index);
1496 } else if (clk->ops->set_parent) {
1497 clk->ops->set_parent(clk->hw, clk->new_parent_index);
1500 __clk_set_parent_after(clk, clk->new_parent, old_parent);
1503 if (!skip_set_rate && clk->ops->set_rate)
1504 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1506 clk->rate = clk_recalc(clk, best_parent_rate);
1508 if (clk->notifier_count && old_rate != clk->rate)
1509 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1511 hlist_for_each_entry(child, &clk->children, child_node) {
1512 /* Skip children who will be reparented to another clock */
1513 if (child->new_parent && child->new_parent != clk)
1515 clk_change_rate(child);
1518 /* handle the new child who might not be in clk->children yet */
1520 clk_change_rate(clk->new_child);
1524 * clk_set_rate - specify a new rate for clk
1525 * @clk: the clk whose rate is being changed
1526 * @rate: the new rate for clk
1528 * In the simplest case clk_set_rate will only adjust the rate of clk.
1530 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1531 * propagate up to clk's parent; whether or not this happens depends on the
1532 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1533 * after calling .round_rate then upstream parent propagation is ignored. If
1534 * *parent_rate comes back with a new rate for clk's parent then we propagate
1535 * up to clk's parent and set its rate. Upward propagation will continue
1536 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1537 * .round_rate stops requesting changes to clk's parent_rate.
1539 * Rate changes are accomplished via tree traversal that also recalculates the
1540 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1542 * Returns 0 on success, -EERROR otherwise.
1544 int clk_set_rate(struct clk *clk, unsigned long rate)
1546 struct clk *top, *fail_clk;
1552 /* prevent racing with updates to the clock topology */
1555 /* bail early if nothing to do */
1556 if (rate == clk_get_rate(clk))
1559 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1564 /* calculate new rates and get the topmost changed clock */
1565 top = clk_calc_new_rates(clk, rate);
1571 /* notify that we are about to change rates */
1572 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1574 pr_debug("%s: failed to set %s rate\n", __func__,
1576 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1581 /* change the rates */
1582 clk_change_rate(top);
1585 clk_prepare_unlock();
1589 EXPORT_SYMBOL_GPL(clk_set_rate);
1592 * clk_get_parent - return the parent of a clk
1593 * @clk: the clk whose parent gets returned
1595 * Simply returns clk->parent. Returns NULL if clk is NULL.
1597 struct clk *clk_get_parent(struct clk *clk)
1602 parent = __clk_get_parent(clk);
1603 clk_prepare_unlock();
1607 EXPORT_SYMBOL_GPL(clk_get_parent);
1610 * .get_parent is mandatory for clocks with multiple possible parents. It is
1611 * optional for single-parent clocks. Always call .get_parent if it is
1612 * available and WARN if it is missing for multi-parent clocks.
1614 * For single-parent clocks without .get_parent, first check to see if the
1615 * .parents array exists, and if so use it to avoid an expensive tree
1616 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1618 static struct clk *__clk_init_parent(struct clk *clk)
1620 struct clk *ret = NULL;
1623 /* handle the trivial cases */
1625 if (!clk->num_parents)
1628 if (clk->num_parents == 1) {
1629 if (IS_ERR_OR_NULL(clk->parent))
1630 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1635 if (!clk->ops->get_parent) {
1636 WARN(!clk->ops->get_parent,
1637 "%s: multi-parent clocks must implement .get_parent\n",
1643 * Do our best to cache parent clocks in clk->parents. This prevents
1644 * unnecessary and expensive calls to __clk_lookup. We don't set
1645 * clk->parent here; that is done by the calling function
1648 index = clk->ops->get_parent(clk->hw);
1652 kcalloc(clk->num_parents, sizeof(struct clk *),
1655 ret = clk_get_parent_by_index(clk, index);
1661 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1663 clk_reparent(clk, new_parent);
1664 __clk_recalc_accuracies(clk);
1665 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1669 * clk_set_parent - switch the parent of a mux clk
1670 * @clk: the mux clk whose input we are switching
1671 * @parent: the new input to clk
1673 * Re-parent clk to use parent as its new input source. If clk is in
1674 * prepared state, the clk will get enabled for the duration of this call. If
1675 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1676 * that, the reparenting is glitchy in hardware, etc), use the
1677 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1679 * After successfully changing clk's parent clk_set_parent will update the
1680 * clk topology, sysfs topology and propagate rate recalculation via
1681 * __clk_recalc_rates.
1683 * Returns 0 on success, -EERROR otherwise.
1685 int clk_set_parent(struct clk *clk, struct clk *parent)
1689 unsigned long p_rate = 0;
1694 /* verify ops for for multi-parent clks */
1695 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1698 /* prevent racing with updates to the clock topology */
1701 if (clk->parent == parent)
1704 /* check that we are allowed to re-parent if the clock is in use */
1705 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1710 /* try finding the new parent index */
1712 p_index = clk_fetch_parent_index(clk, parent);
1713 p_rate = parent->rate;
1715 pr_debug("%s: clk %s can not be parent of clk %s\n",
1716 __func__, parent->name, clk->name);
1722 /* propagate PRE_RATE_CHANGE notifications */
1723 ret = __clk_speculate_rates(clk, p_rate);
1725 /* abort if a driver objects */
1726 if (ret & NOTIFY_STOP_MASK)
1729 /* do the re-parent */
1730 ret = __clk_set_parent(clk, parent, p_index);
1732 /* propagate rate an accuracy recalculation accordingly */
1734 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1736 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1737 __clk_recalc_accuracies(clk);
1741 clk_prepare_unlock();
1745 EXPORT_SYMBOL_GPL(clk_set_parent);
1748 * clk_set_phase - adjust the phase shift of a clock signal
1749 * @clk: clock signal source
1750 * @degrees: number of degrees the signal is shifted
1752 * Shifts the phase of a clock signal by the specified
1753 * degrees. Returns 0 on success, -EERROR otherwise.
1755 * This function makes no distinction about the input or reference
1756 * signal that we adjust the clock signal phase against. For example
1757 * phase locked-loop clock signal generators we may shift phase with
1758 * respect to feedback clock signal input, but for other cases the
1759 * clock phase may be shifted with respect to some other, unspecified
1762 * Additionally the concept of phase shift does not propagate through
1763 * the clock tree hierarchy, which sets it apart from clock rates and
1764 * clock accuracy. A parent clock phase attribute does not have an
1765 * impact on the phase attribute of a child clock.
1767 int clk_set_phase(struct clk *clk, int degrees)
1774 /* sanity check degrees */
1781 if (!clk->ops->set_phase)
1784 ret = clk->ops->set_phase(clk->hw, degrees);
1787 clk->phase = degrees;
1790 clk_prepare_unlock();
1797 * clk_get_phase - return the phase shift of a clock signal
1798 * @clk: clock signal source
1800 * Returns the phase shift of a clock node in degrees, otherwise returns
1803 int clk_get_phase(struct clk *clk)
1812 clk_prepare_unlock();
1819 * __clk_init - initialize the data structures in a struct clk
1820 * @dev: device initializing this clk, placeholder for now
1821 * @clk: clk being initialized
1823 * Initializes the lists in struct clk, queries the hardware for the
1824 * parent and rate and sets them both.
1826 int __clk_init(struct device *dev, struct clk *clk)
1830 struct hlist_node *tmp2;
1837 /* check to see if a clock with this name is already registered */
1838 if (__clk_lookup(clk->name)) {
1839 pr_debug("%s: clk %s already initialized\n",
1840 __func__, clk->name);
1845 /* check that clk_ops are sane. See Documentation/clk.txt */
1846 if (clk->ops->set_rate &&
1847 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1848 clk->ops->recalc_rate)) {
1849 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1850 __func__, clk->name);
1855 if (clk->ops->set_parent && !clk->ops->get_parent) {
1856 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1857 __func__, clk->name);
1862 if (clk->ops->set_rate_and_parent &&
1863 !(clk->ops->set_parent && clk->ops->set_rate)) {
1864 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
1865 __func__, clk->name);
1870 /* throw a WARN if any entries in parent_names are NULL */
1871 for (i = 0; i < clk->num_parents; i++)
1872 WARN(!clk->parent_names[i],
1873 "%s: invalid NULL in %s's .parent_names\n",
1874 __func__, clk->name);
1877 * Allocate an array of struct clk *'s to avoid unnecessary string
1878 * look-ups of clk's possible parents. This can fail for clocks passed
1879 * in to clk_init during early boot; thus any access to clk->parents[]
1880 * must always check for a NULL pointer and try to populate it if
1883 * If clk->parents is not NULL we skip this entire block. This allows
1884 * for clock drivers to statically initialize clk->parents.
1886 if (clk->num_parents > 1 && !clk->parents) {
1887 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
1890 * __clk_lookup returns NULL for parents that have not been
1891 * clk_init'd; thus any access to clk->parents[] must check
1892 * for a NULL pointer. We can always perform lazy lookups for
1893 * missing parents later on.
1896 for (i = 0; i < clk->num_parents; i++)
1898 __clk_lookup(clk->parent_names[i]);
1901 clk->parent = __clk_init_parent(clk);
1904 * Populate clk->parent if parent has already been __clk_init'd. If
1905 * parent has not yet been __clk_init'd then place clk in the orphan
1906 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1909 * Every time a new clk is clk_init'd then we walk the list of orphan
1910 * clocks and re-parent any that are children of the clock currently
1914 hlist_add_head(&clk->child_node,
1915 &clk->parent->children);
1916 else if (clk->flags & CLK_IS_ROOT)
1917 hlist_add_head(&clk->child_node, &clk_root_list);
1919 hlist_add_head(&clk->child_node, &clk_orphan_list);
1922 * Set clk's accuracy. The preferred method is to use
1923 * .recalc_accuracy. For simple clocks and lazy developers the default
1924 * fallback is to use the parent's accuracy. If a clock doesn't have a
1925 * parent (or is orphaned) then accuracy is set to zero (perfect
1928 if (clk->ops->recalc_accuracy)
1929 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1930 __clk_get_accuracy(clk->parent));
1931 else if (clk->parent)
1932 clk->accuracy = clk->parent->accuracy;
1938 * Since a phase is by definition relative to its parent, just
1939 * query the current clock phase, or just assume it's in phase.
1941 if (clk->ops->get_phase)
1942 clk->phase = clk->ops->get_phase(clk->hw);
1947 * Set clk's rate. The preferred method is to use .recalc_rate. For
1948 * simple clocks and lazy developers the default fallback is to use the
1949 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1950 * then rate is set to zero.
1952 if (clk->ops->recalc_rate)
1953 clk->rate = clk->ops->recalc_rate(clk->hw,
1954 __clk_get_rate(clk->parent));
1955 else if (clk->parent)
1956 clk->rate = clk->parent->rate;
1960 clk_debug_register(clk);
1962 * walk the list of orphan clocks and reparent any that are children of
1965 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1966 if (orphan->num_parents && orphan->ops->get_parent) {
1967 i = orphan->ops->get_parent(orphan->hw);
1968 if (!strcmp(clk->name, orphan->parent_names[i]))
1969 __clk_reparent(orphan, clk);
1973 for (i = 0; i < orphan->num_parents; i++)
1974 if (!strcmp(clk->name, orphan->parent_names[i])) {
1975 __clk_reparent(orphan, clk);
1981 * optional platform-specific magic
1983 * The .init callback is not used by any of the basic clock types, but
1984 * exists for weird hardware that must perform initialization magic.
1985 * Please consider other ways of solving initialization problems before
1986 * using this callback, as its use is discouraged.
1989 clk->ops->init(clk->hw);
1991 kref_init(&clk->ref);
1993 clk_prepare_unlock();
1999 * __clk_register - register a clock and return a cookie.
2001 * Same as clk_register, except that the .clk field inside hw shall point to a
2002 * preallocated (generally statically allocated) struct clk. None of the fields
2003 * of the struct clk need to be initialized.
2005 * The data pointed to by .init and .clk field shall NOT be marked as init
2008 * __clk_register is only exposed via clk-private.h and is intended for use with
2009 * very large numbers of clocks that need to be statically initialized. It is
2010 * a layering violation to include clk-private.h from any code which implements
2011 * a clock's .ops; as such any statically initialized clock data MUST be in a
2012 * separate C file from the logic that implements its operations. Returns 0
2013 * on success, otherwise an error code.
2015 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
2021 clk->name = hw->init->name;
2022 clk->ops = hw->init->ops;
2024 clk->flags = hw->init->flags;
2025 clk->parent_names = hw->init->parent_names;
2026 clk->num_parents = hw->init->num_parents;
2027 if (dev && dev->driver)
2028 clk->owner = dev->driver->owner;
2032 ret = __clk_init(dev, clk);
2034 return ERR_PTR(ret);
2038 EXPORT_SYMBOL_GPL(__clk_register);
2041 * clk_register - allocate a new clock, register it and return an opaque cookie
2042 * @dev: device that is registering this clock
2043 * @hw: link to hardware-specific clock data
2045 * clk_register is the primary interface for populating the clock tree with new
2046 * clock nodes. It returns a pointer to the newly allocated struct clk which
2047 * cannot be dereferenced by driver code but may be used in conjuction with the
2048 * rest of the clock API. In the event of an error clk_register will return an
2049 * error code; drivers must test for an error code after calling clk_register.
2051 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
2056 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2058 pr_err("%s: could not allocate clk\n", __func__);
2063 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
2065 pr_err("%s: could not allocate clk->name\n", __func__);
2069 clk->ops = hw->init->ops;
2070 if (dev && dev->driver)
2071 clk->owner = dev->driver->owner;
2073 clk->flags = hw->init->flags;
2074 clk->num_parents = hw->init->num_parents;
2077 /* allocate local copy in case parent_names is __initdata */
2078 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
2081 if (!clk->parent_names) {
2082 pr_err("%s: could not allocate clk->parent_names\n", __func__);
2084 goto fail_parent_names;
2088 /* copy each string name in case parent_names is __initdata */
2089 for (i = 0; i < clk->num_parents; i++) {
2090 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
2092 if (!clk->parent_names[i]) {
2093 pr_err("%s: could not copy parent_names\n", __func__);
2095 goto fail_parent_names_copy;
2099 ret = __clk_init(dev, clk);
2103 fail_parent_names_copy:
2105 kfree(clk->parent_names[i]);
2106 kfree(clk->parent_names);
2112 return ERR_PTR(ret);
2114 EXPORT_SYMBOL_GPL(clk_register);
2117 * Free memory allocated for a clock.
2118 * Caller must hold prepare_lock.
2120 static void __clk_release(struct kref *ref)
2122 struct clk *clk = container_of(ref, struct clk, ref);
2123 int i = clk->num_parents;
2125 kfree(clk->parents);
2127 kfree(clk->parent_names[i]);
2129 kfree(clk->parent_names);
2135 * Empty clk_ops for unregistered clocks. These are used temporarily
2136 * after clk_unregister() was called on a clock and until last clock
2137 * consumer calls clk_put() and the struct clk object is freed.
2139 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2144 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2149 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2150 unsigned long parent_rate)
2155 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2160 static const struct clk_ops clk_nodrv_ops = {
2161 .enable = clk_nodrv_prepare_enable,
2162 .disable = clk_nodrv_disable_unprepare,
2163 .prepare = clk_nodrv_prepare_enable,
2164 .unprepare = clk_nodrv_disable_unprepare,
2165 .set_rate = clk_nodrv_set_rate,
2166 .set_parent = clk_nodrv_set_parent,
2170 * clk_unregister - unregister a currently registered clock
2171 * @clk: clock to unregister
2173 void clk_unregister(struct clk *clk)
2175 unsigned long flags;
2177 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2182 if (clk->ops == &clk_nodrv_ops) {
2183 pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
2187 * Assign empty clock ops for consumers that might still hold
2188 * a reference to this clock.
2190 flags = clk_enable_lock();
2191 clk->ops = &clk_nodrv_ops;
2192 clk_enable_unlock(flags);
2194 if (!hlist_empty(&clk->children)) {
2196 struct hlist_node *t;
2198 /* Reparent all children to the orphan list. */
2199 hlist_for_each_entry_safe(child, t, &clk->children, child_node)
2200 clk_set_parent(child, NULL);
2203 clk_debug_unregister(clk);
2205 hlist_del_init(&clk->child_node);
2207 if (clk->prepare_count)
2208 pr_warn("%s: unregistering prepared clock: %s\n",
2209 __func__, clk->name);
2211 kref_put(&clk->ref, __clk_release);
2213 clk_prepare_unlock();
2215 EXPORT_SYMBOL_GPL(clk_unregister);
2217 static void devm_clk_release(struct device *dev, void *res)
2219 clk_unregister(*(struct clk **)res);
2223 * devm_clk_register - resource managed clk_register()
2224 * @dev: device that is registering this clock
2225 * @hw: link to hardware-specific clock data
2227 * Managed clk_register(). Clocks returned from this function are
2228 * automatically clk_unregister()ed on driver detach. See clk_register() for
2231 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2236 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2238 return ERR_PTR(-ENOMEM);
2240 clk = clk_register(dev, hw);
2243 devres_add(dev, clkp);
2250 EXPORT_SYMBOL_GPL(devm_clk_register);
2252 static int devm_clk_match(struct device *dev, void *res, void *data)
2254 struct clk *c = res;
2261 * devm_clk_unregister - resource managed clk_unregister()
2262 * @clk: clock to unregister
2264 * Deallocate a clock allocated with devm_clk_register(). Normally
2265 * this function will not need to be called and the resource management
2266 * code will ensure that the resource is freed.
2268 void devm_clk_unregister(struct device *dev, struct clk *clk)
2270 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2272 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2277 int __clk_get(struct clk *clk)
2280 if (!try_module_get(clk->owner))
2283 kref_get(&clk->ref);
2288 void __clk_put(struct clk *clk)
2290 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2294 kref_put(&clk->ref, __clk_release);
2295 clk_prepare_unlock();
2297 module_put(clk->owner);
2300 /*** clk rate change notifiers ***/
2303 * clk_notifier_register - add a clk rate change notifier
2304 * @clk: struct clk * to watch
2305 * @nb: struct notifier_block * with callback info
2307 * Request notification when clk's rate changes. This uses an SRCU
2308 * notifier because we want it to block and notifier unregistrations are
2309 * uncommon. The callbacks associated with the notifier must not
2310 * re-enter into the clk framework by calling any top-level clk APIs;
2311 * this will cause a nested prepare_lock mutex.
2313 * In all notification cases cases (pre, post and abort rate change) the
2314 * original clock rate is passed to the callback via struct
2315 * clk_notifier_data.old_rate and the new frequency is passed via struct
2316 * clk_notifier_data.new_rate.
2318 * clk_notifier_register() must be called from non-atomic context.
2319 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2320 * allocation failure; otherwise, passes along the return value of
2321 * srcu_notifier_chain_register().
2323 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2325 struct clk_notifier *cn;
2333 /* search the list of notifiers for this clk */
2334 list_for_each_entry(cn, &clk_notifier_list, node)
2338 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2339 if (cn->clk != clk) {
2340 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2345 srcu_init_notifier_head(&cn->notifier_head);
2347 list_add(&cn->node, &clk_notifier_list);
2350 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2352 clk->notifier_count++;
2355 clk_prepare_unlock();
2359 EXPORT_SYMBOL_GPL(clk_notifier_register);
2362 * clk_notifier_unregister - remove a clk rate change notifier
2363 * @clk: struct clk *
2364 * @nb: struct notifier_block * with callback info
2366 * Request no further notification for changes to 'clk' and frees memory
2367 * allocated in clk_notifier_register.
2369 * Returns -EINVAL if called with null arguments; otherwise, passes
2370 * along the return value of srcu_notifier_chain_unregister().
2372 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2374 struct clk_notifier *cn = NULL;
2382 list_for_each_entry(cn, &clk_notifier_list, node)
2386 if (cn->clk == clk) {
2387 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2389 clk->notifier_count--;
2391 /* XXX the notifier code should handle this better */
2392 if (!cn->notifier_head.head) {
2393 srcu_cleanup_notifier_head(&cn->notifier_head);
2394 list_del(&cn->node);
2402 clk_prepare_unlock();
2406 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2410 * struct of_clk_provider - Clock provider registration structure
2411 * @link: Entry in global list of clock providers
2412 * @node: Pointer to device tree node of clock provider
2413 * @get: Get clock callback. Returns NULL or a struct clk for the
2414 * given clock specifier
2415 * @data: context pointer to be passed into @get callback
2417 struct of_clk_provider {
2418 struct list_head link;
2420 struct device_node *node;
2421 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2425 static const struct of_device_id __clk_of_table_sentinel
2426 __used __section(__clk_of_table_end);
2428 static LIST_HEAD(of_clk_providers);
2429 static DEFINE_MUTEX(of_clk_mutex);
2431 /* of_clk_provider list locking helpers */
2432 void of_clk_lock(void)
2434 mutex_lock(&of_clk_mutex);
2437 void of_clk_unlock(void)
2439 mutex_unlock(&of_clk_mutex);
2442 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2447 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2449 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2451 struct clk_onecell_data *clk_data = data;
2452 unsigned int idx = clkspec->args[0];
2454 if (idx >= clk_data->clk_num) {
2455 pr_err("%s: invalid clock index %d\n", __func__, idx);
2456 return ERR_PTR(-EINVAL);
2459 return clk_data->clks[idx];
2461 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2464 * of_clk_add_provider() - Register a clock provider for a node
2465 * @np: Device node pointer associated with clock provider
2466 * @clk_src_get: callback for decoding clock
2467 * @data: context pointer for @clk_src_get callback.
2469 int of_clk_add_provider(struct device_node *np,
2470 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2474 struct of_clk_provider *cp;
2477 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2481 cp->node = of_node_get(np);
2483 cp->get = clk_src_get;
2485 mutex_lock(&of_clk_mutex);
2486 list_add(&cp->link, &of_clk_providers);
2487 mutex_unlock(&of_clk_mutex);
2488 pr_debug("Added clock from %s\n", np->full_name);
2490 ret = of_clk_set_defaults(np, true);
2492 of_clk_del_provider(np);
2496 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2499 * of_clk_del_provider() - Remove a previously registered clock provider
2500 * @np: Device node pointer associated with clock provider
2502 void of_clk_del_provider(struct device_node *np)
2504 struct of_clk_provider *cp;
2506 mutex_lock(&of_clk_mutex);
2507 list_for_each_entry(cp, &of_clk_providers, link) {
2508 if (cp->node == np) {
2509 list_del(&cp->link);
2510 of_node_put(cp->node);
2515 mutex_unlock(&of_clk_mutex);
2517 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2519 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec)
2521 struct of_clk_provider *provider;
2522 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2524 /* Check if we have such a provider in our array */
2525 list_for_each_entry(provider, &of_clk_providers, link) {
2526 if (provider->node == clkspec->np)
2527 clk = provider->get(clkspec, provider->data);
2535 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2539 mutex_lock(&of_clk_mutex);
2540 clk = __of_clk_get_from_provider(clkspec);
2541 mutex_unlock(&of_clk_mutex);
2546 int of_clk_get_parent_count(struct device_node *np)
2548 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2550 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2552 const char *of_clk_get_parent_name(struct device_node *np, int index)
2554 struct of_phandle_args clkspec;
2555 struct property *prop;
2556 const char *clk_name;
2565 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2570 index = clkspec.args_count ? clkspec.args[0] : 0;
2573 /* if there is an indices property, use it to transfer the index
2574 * specified into an array offset for the clock-output-names property.
2576 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
2584 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2587 clk_name = clkspec.np->name;
2589 of_node_put(clkspec.np);
2592 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2594 struct clock_provider {
2595 of_clk_init_cb_t clk_init_cb;
2596 struct device_node *np;
2597 struct list_head node;
2600 static LIST_HEAD(clk_provider_list);
2603 * This function looks for a parent clock. If there is one, then it
2604 * checks that the provider for this parent clock was initialized, in
2605 * this case the parent clock will be ready.
2607 static int parent_ready(struct device_node *np)
2612 struct clk *clk = of_clk_get(np, i);
2614 /* this parent is ready we can check the next one */
2621 /* at least one parent is not ready, we exit now */
2622 if (PTR_ERR(clk) == -EPROBE_DEFER)
2626 * Here we make assumption that the device tree is
2627 * written correctly. So an error means that there is
2628 * no more parent. As we didn't exit yet, then the
2629 * previous parent are ready. If there is no clock
2630 * parent, no need to wait for them, then we can
2631 * consider their absence as being ready
2638 * of_clk_init() - Scan and init clock providers from the DT
2639 * @matches: array of compatible values and init functions for providers.
2641 * This function scans the device tree for matching clock providers
2642 * and calls their initialization functions. It also does it by trying
2643 * to follow the dependencies.
2645 void __init of_clk_init(const struct of_device_id *matches)
2647 const struct of_device_id *match;
2648 struct device_node *np;
2649 struct clock_provider *clk_provider, *next;
2654 matches = &__clk_of_table;
2656 /* First prepare the list of the clocks providers */
2657 for_each_matching_node_and_match(np, matches, &match) {
2658 struct clock_provider *parent =
2659 kzalloc(sizeof(struct clock_provider), GFP_KERNEL);
2661 parent->clk_init_cb = match->data;
2663 list_add_tail(&parent->node, &clk_provider_list);
2666 while (!list_empty(&clk_provider_list)) {
2667 is_init_done = false;
2668 list_for_each_entry_safe(clk_provider, next,
2669 &clk_provider_list, node) {
2670 if (force || parent_ready(clk_provider->np)) {
2672 clk_provider->clk_init_cb(clk_provider->np);
2673 of_clk_set_defaults(clk_provider->np, true);
2675 list_del(&clk_provider->node);
2676 kfree(clk_provider);
2677 is_init_done = true;
2682 * We didn't manage to initialize any of the
2683 * remaining providers during the last loop, so now we
2684 * initialize all the remaining ones unconditionally
2685 * in case the clock parent was not mandatory