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;
103 static DEFINE_MUTEX(clk_debug_lock);
104 static HLIST_HEAD(clk_debug_list);
106 static struct hlist_head *all_lists[] = {
112 static struct hlist_head *orphan_list[] = {
117 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
122 seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
124 30 - level * 3, c->name,
125 c->enable_count, c->prepare_count, clk_get_rate(c),
126 clk_get_accuracy(c), clk_get_phase(c));
129 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
137 clk_summary_show_one(s, c, level);
139 hlist_for_each_entry(child, &c->children, child_node)
140 clk_summary_show_subtree(s, child, level + 1);
143 static int clk_summary_show(struct seq_file *s, void *data)
146 struct hlist_head **lists = (struct hlist_head **)s->private;
148 seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy phase\n");
149 seq_puts(s, "----------------------------------------------------------------------------------------\n");
153 for (; *lists; lists++)
154 hlist_for_each_entry(c, *lists, child_node)
155 clk_summary_show_subtree(s, c, 0);
157 clk_prepare_unlock();
163 static int clk_summary_open(struct inode *inode, struct file *file)
165 return single_open(file, clk_summary_show, inode->i_private);
168 static const struct file_operations clk_summary_fops = {
169 .open = clk_summary_open,
172 .release = single_release,
175 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
180 seq_printf(s, "\"%s\": { ", c->name);
181 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
182 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
183 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
184 seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
185 seq_printf(s, "\"phase\": %d", clk_get_phase(c));
188 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
195 clk_dump_one(s, c, level);
197 hlist_for_each_entry(child, &c->children, child_node) {
199 clk_dump_subtree(s, child, level + 1);
205 static int clk_dump(struct seq_file *s, void *data)
208 bool first_node = true;
209 struct hlist_head **lists = (struct hlist_head **)s->private;
215 for (; *lists; lists++) {
216 hlist_for_each_entry(c, *lists, child_node) {
220 clk_dump_subtree(s, c, 0);
224 clk_prepare_unlock();
231 static int clk_dump_open(struct inode *inode, struct file *file)
233 return single_open(file, clk_dump, inode->i_private);
236 static const struct file_operations clk_dump_fops = {
237 .open = clk_dump_open,
240 .release = single_release,
243 /* caller must hold prepare_lock */
244 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
249 if (!clk || !pdentry) {
254 d = debugfs_create_dir(clk->name, pdentry);
260 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
265 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
266 (u32 *)&clk->accuracy);
270 d = debugfs_create_u32("clk_phase", S_IRUGO, clk->dentry,
275 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
280 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
281 (u32 *)&clk->prepare_count);
285 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
286 (u32 *)&clk->enable_count);
290 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
291 (u32 *)&clk->notifier_count);
295 if (clk->ops->debug_init) {
296 ret = clk->ops->debug_init(clk->hw, clk->dentry);
305 debugfs_remove_recursive(clk->dentry);
312 * clk_debug_register - add a clk node to the debugfs clk tree
313 * @clk: the clk being added to the debugfs clk tree
315 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
316 * initialized. Otherwise it bails out early since the debugfs clk tree
317 * will be created lazily by clk_debug_init as part of a late_initcall.
319 static int clk_debug_register(struct clk *clk)
323 mutex_lock(&clk_debug_lock);
324 hlist_add_head(&clk->debug_node, &clk_debug_list);
329 ret = clk_debug_create_one(clk, rootdir);
331 mutex_unlock(&clk_debug_lock);
337 * clk_debug_unregister - remove a clk node from the debugfs clk tree
338 * @clk: the clk being removed from the debugfs clk tree
340 * Dynamically removes a clk and all it's children clk nodes from the
341 * debugfs clk tree if clk->dentry points to debugfs created by
342 * clk_debug_register in __clk_init.
344 static void clk_debug_unregister(struct clk *clk)
346 mutex_lock(&clk_debug_lock);
350 hlist_del_init(&clk->debug_node);
351 debugfs_remove_recursive(clk->dentry);
354 mutex_unlock(&clk_debug_lock);
357 struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
358 void *data, const struct file_operations *fops)
360 struct dentry *d = NULL;
363 d = debugfs_create_file(name, mode, clk->dentry, data, fops);
367 EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
370 * clk_debug_init - lazily create the debugfs clk tree visualization
372 * clks are often initialized very early during boot before memory can
373 * be dynamically allocated and well before debugfs is setup.
374 * clk_debug_init walks the clk tree hierarchy while holding
375 * prepare_lock and creates the topology as part of a late_initcall,
376 * thus insuring that clks initialized very early will still be
377 * represented in the debugfs clk tree. This function should only be
378 * called once at boot-time, and all other clks added dynamically will
379 * be done so with clk_debug_register.
381 static int __init clk_debug_init(void)
386 rootdir = debugfs_create_dir("clk", NULL);
391 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists,
396 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists,
401 d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir,
402 &orphan_list, &clk_summary_fops);
406 d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir,
407 &orphan_list, &clk_dump_fops);
411 mutex_lock(&clk_debug_lock);
412 hlist_for_each_entry(clk, &clk_debug_list, debug_node)
413 clk_debug_create_one(clk, rootdir);
416 mutex_unlock(&clk_debug_lock);
420 late_initcall(clk_debug_init);
422 static inline int clk_debug_register(struct clk *clk) { return 0; }
423 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
426 static inline void clk_debug_unregister(struct clk *clk)
431 /* caller must hold prepare_lock */
432 static void clk_unprepare_unused_subtree(struct clk *clk)
439 hlist_for_each_entry(child, &clk->children, child_node)
440 clk_unprepare_unused_subtree(child);
442 if (clk->prepare_count)
445 if (clk->flags & CLK_IGNORE_UNUSED)
448 if (__clk_is_prepared(clk)) {
449 if (clk->ops->unprepare_unused)
450 clk->ops->unprepare_unused(clk->hw);
451 else if (clk->ops->unprepare)
452 clk->ops->unprepare(clk->hw);
456 /* caller must hold prepare_lock */
457 static void clk_disable_unused_subtree(struct clk *clk)
465 hlist_for_each_entry(child, &clk->children, child_node)
466 clk_disable_unused_subtree(child);
468 flags = clk_enable_lock();
470 if (clk->enable_count)
473 if (clk->flags & CLK_IGNORE_UNUSED)
477 * some gate clocks have special needs during the disable-unused
478 * sequence. call .disable_unused if available, otherwise fall
481 if (__clk_is_enabled(clk)) {
482 if (clk->ops->disable_unused)
483 clk->ops->disable_unused(clk->hw);
484 else if (clk->ops->disable)
485 clk->ops->disable(clk->hw);
489 clk_enable_unlock(flags);
495 static bool clk_ignore_unused;
496 static int __init clk_ignore_unused_setup(char *__unused)
498 clk_ignore_unused = true;
501 __setup("clk_ignore_unused", clk_ignore_unused_setup);
503 static int clk_disable_unused(void)
507 if (clk_ignore_unused) {
508 pr_warn("clk: Not disabling unused clocks\n");
514 hlist_for_each_entry(clk, &clk_root_list, child_node)
515 clk_disable_unused_subtree(clk);
517 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
518 clk_disable_unused_subtree(clk);
520 hlist_for_each_entry(clk, &clk_root_list, child_node)
521 clk_unprepare_unused_subtree(clk);
523 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
524 clk_unprepare_unused_subtree(clk);
526 clk_prepare_unlock();
530 late_initcall_sync(clk_disable_unused);
532 /*** helper functions ***/
534 const char *__clk_get_name(struct clk *clk)
536 return !clk ? NULL : clk->name;
538 EXPORT_SYMBOL_GPL(__clk_get_name);
540 struct clk_hw *__clk_get_hw(struct clk *clk)
542 return !clk ? NULL : clk->hw;
544 EXPORT_SYMBOL_GPL(__clk_get_hw);
546 u8 __clk_get_num_parents(struct clk *clk)
548 return !clk ? 0 : clk->num_parents;
550 EXPORT_SYMBOL_GPL(__clk_get_num_parents);
552 struct clk *__clk_get_parent(struct clk *clk)
554 return !clk ? NULL : clk->parent;
556 EXPORT_SYMBOL_GPL(__clk_get_parent);
558 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
560 if (!clk || index >= clk->num_parents)
562 else if (!clk->parents)
563 return __clk_lookup(clk->parent_names[index]);
564 else if (!clk->parents[index])
565 return clk->parents[index] =
566 __clk_lookup(clk->parent_names[index]);
568 return clk->parents[index];
570 EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
572 unsigned int __clk_get_enable_count(struct clk *clk)
574 return !clk ? 0 : clk->enable_count;
577 unsigned long __clk_get_rate(struct clk *clk)
588 if (clk->flags & CLK_IS_ROOT)
597 EXPORT_SYMBOL_GPL(__clk_get_rate);
599 unsigned long __clk_get_accuracy(struct clk *clk)
604 return clk->accuracy;
607 unsigned long __clk_get_flags(struct clk *clk)
609 return !clk ? 0 : clk->flags;
611 EXPORT_SYMBOL_GPL(__clk_get_flags);
613 bool __clk_is_prepared(struct clk *clk)
621 * .is_prepared is optional for clocks that can prepare
622 * fall back to software usage counter if it is missing
624 if (!clk->ops->is_prepared) {
625 ret = clk->prepare_count ? 1 : 0;
629 ret = clk->ops->is_prepared(clk->hw);
634 bool __clk_is_enabled(struct clk *clk)
642 * .is_enabled is only mandatory for clocks that gate
643 * fall back to software usage counter if .is_enabled is missing
645 if (!clk->ops->is_enabled) {
646 ret = clk->enable_count ? 1 : 0;
650 ret = clk->ops->is_enabled(clk->hw);
654 EXPORT_SYMBOL_GPL(__clk_is_enabled);
656 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
661 if (!strcmp(clk->name, name))
664 hlist_for_each_entry(child, &clk->children, child_node) {
665 ret = __clk_lookup_subtree(name, child);
673 struct clk *__clk_lookup(const char *name)
675 struct clk *root_clk;
681 /* search the 'proper' clk tree first */
682 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
683 ret = __clk_lookup_subtree(name, root_clk);
688 /* if not found, then search the orphan tree */
689 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
690 ret = __clk_lookup_subtree(name, root_clk);
699 * Helper for finding best parent to provide a given frequency. This can be used
700 * directly as a determine_rate callback (e.g. for a mux), or from a more
701 * complex clock that may combine a mux with other operations.
703 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
704 unsigned long *best_parent_rate,
705 struct clk **best_parent_p)
707 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
709 unsigned long parent_rate, best = 0;
711 /* if NO_REPARENT flag set, pass through to current parent */
712 if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
713 parent = clk->parent;
714 if (clk->flags & CLK_SET_RATE_PARENT)
715 best = __clk_round_rate(parent, rate);
717 best = __clk_get_rate(parent);
719 best = __clk_get_rate(clk);
723 /* find the parent that can provide the fastest rate <= rate */
724 num_parents = clk->num_parents;
725 for (i = 0; i < num_parents; i++) {
726 parent = clk_get_parent_by_index(clk, i);
729 if (clk->flags & CLK_SET_RATE_PARENT)
730 parent_rate = __clk_round_rate(parent, rate);
732 parent_rate = __clk_get_rate(parent);
733 if (parent_rate <= rate && parent_rate > best) {
734 best_parent = parent;
741 *best_parent_p = best_parent;
742 *best_parent_rate = best;
746 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
750 void __clk_unprepare(struct clk *clk)
755 if (WARN_ON(clk->prepare_count == 0))
758 if (--clk->prepare_count > 0)
761 WARN_ON(clk->enable_count > 0);
763 if (clk->ops->unprepare)
764 clk->ops->unprepare(clk->hw);
766 __clk_unprepare(clk->parent);
770 * clk_unprepare - undo preparation of a clock source
771 * @clk: the clk being unprepared
773 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
774 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
775 * if the operation may sleep. One example is a clk which is accessed over
776 * I2c. In the complex case a clk gate operation may require a fast and a slow
777 * part. It is this reason that clk_unprepare and clk_disable are not mutually
778 * exclusive. In fact clk_disable must be called before clk_unprepare.
780 void clk_unprepare(struct clk *clk)
782 if (IS_ERR_OR_NULL(clk))
786 __clk_unprepare(clk);
787 clk_prepare_unlock();
789 EXPORT_SYMBOL_GPL(clk_unprepare);
791 int __clk_prepare(struct clk *clk)
798 if (clk->prepare_count == 0) {
799 ret = __clk_prepare(clk->parent);
803 if (clk->ops->prepare) {
804 ret = clk->ops->prepare(clk->hw);
806 __clk_unprepare(clk->parent);
812 clk->prepare_count++;
818 * clk_prepare - prepare a clock source
819 * @clk: the clk being prepared
821 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
822 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
823 * operation may sleep. One example is a clk which is accessed over I2c. In
824 * the complex case a clk ungate operation may require a fast and a slow part.
825 * It is this reason that clk_prepare and clk_enable are not mutually
826 * exclusive. In fact clk_prepare must be called before clk_enable.
827 * Returns 0 on success, -EERROR otherwise.
829 int clk_prepare(struct clk *clk)
834 ret = __clk_prepare(clk);
835 clk_prepare_unlock();
839 EXPORT_SYMBOL_GPL(clk_prepare);
841 static void __clk_disable(struct clk *clk)
846 if (WARN_ON(clk->enable_count == 0))
849 if (--clk->enable_count > 0)
852 if (clk->ops->disable)
853 clk->ops->disable(clk->hw);
855 __clk_disable(clk->parent);
859 * clk_disable - gate a clock
860 * @clk: the clk being gated
862 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
863 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
864 * clk if the operation is fast and will never sleep. One example is a
865 * SoC-internal clk which is controlled via simple register writes. In the
866 * complex case a clk gate operation may require a fast and a slow part. It is
867 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
868 * In fact clk_disable must be called before clk_unprepare.
870 void clk_disable(struct clk *clk)
874 if (IS_ERR_OR_NULL(clk))
877 flags = clk_enable_lock();
879 clk_enable_unlock(flags);
881 EXPORT_SYMBOL_GPL(clk_disable);
883 static int __clk_enable(struct clk *clk)
890 if (WARN_ON(clk->prepare_count == 0))
893 if (clk->enable_count == 0) {
894 ret = __clk_enable(clk->parent);
899 if (clk->ops->enable) {
900 ret = clk->ops->enable(clk->hw);
902 __clk_disable(clk->parent);
913 * clk_enable - ungate a clock
914 * @clk: the clk being ungated
916 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
917 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
918 * if the operation will never sleep. One example is a SoC-internal clk which
919 * is controlled via simple register writes. In the complex case a clk ungate
920 * operation may require a fast and a slow part. It is this reason that
921 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
922 * must be called before clk_enable. Returns 0 on success, -EERROR
925 int clk_enable(struct clk *clk)
930 flags = clk_enable_lock();
931 ret = __clk_enable(clk);
932 clk_enable_unlock(flags);
936 EXPORT_SYMBOL_GPL(clk_enable);
939 * __clk_round_rate - round the given rate for a clk
940 * @clk: round the rate of this clock
941 * @rate: the rate which is to be rounded
943 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
945 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
947 unsigned long parent_rate = 0;
953 parent = clk->parent;
955 parent_rate = parent->rate;
957 if (clk->ops->determine_rate)
958 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
960 else if (clk->ops->round_rate)
961 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
962 else if (clk->flags & CLK_SET_RATE_PARENT)
963 return __clk_round_rate(clk->parent, rate);
967 EXPORT_SYMBOL_GPL(__clk_round_rate);
970 * clk_round_rate - round the given rate for a clk
971 * @clk: the clk for which we are rounding a rate
972 * @rate: the rate which is to be rounded
974 * Takes in a rate as input and rounds it to a rate that the clk can actually
975 * use which is then returned. If clk doesn't support round_rate operation
976 * then the parent rate is returned.
978 long clk_round_rate(struct clk *clk, unsigned long rate)
983 ret = __clk_round_rate(clk, rate);
984 clk_prepare_unlock();
988 EXPORT_SYMBOL_GPL(clk_round_rate);
991 * __clk_notify - call clk notifier chain
992 * @clk: struct clk * that is changing rate
993 * @msg: clk notifier type (see include/linux/clk.h)
994 * @old_rate: old clk rate
995 * @new_rate: new clk rate
997 * Triggers a notifier call chain on the clk rate-change notification
998 * for 'clk'. Passes a pointer to the struct clk and the previous
999 * and current rates to the notifier callback. Intended to be called by
1000 * internal clock code only. Returns NOTIFY_DONE from the last driver
1001 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1002 * a driver returns that.
1004 static int __clk_notify(struct clk *clk, unsigned long msg,
1005 unsigned long old_rate, unsigned long new_rate)
1007 struct clk_notifier *cn;
1008 struct clk_notifier_data cnd;
1009 int ret = NOTIFY_DONE;
1012 cnd.old_rate = old_rate;
1013 cnd.new_rate = new_rate;
1015 list_for_each_entry(cn, &clk_notifier_list, node) {
1016 if (cn->clk == clk) {
1017 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1027 * __clk_recalc_accuracies
1028 * @clk: first clk in the subtree
1030 * Walks the subtree of clks starting with clk and recalculates accuracies as
1031 * it goes. Note that if a clk does not implement the .recalc_accuracy
1032 * callback then it is assumed that the clock will take on the accuracy of it's
1035 * Caller must hold prepare_lock.
1037 static void __clk_recalc_accuracies(struct clk *clk)
1039 unsigned long parent_accuracy = 0;
1043 parent_accuracy = clk->parent->accuracy;
1045 if (clk->ops->recalc_accuracy)
1046 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1049 clk->accuracy = parent_accuracy;
1051 hlist_for_each_entry(child, &clk->children, child_node)
1052 __clk_recalc_accuracies(child);
1056 * clk_get_accuracy - return the accuracy of clk
1057 * @clk: the clk whose accuracy is being returned
1059 * Simply returns the cached accuracy of the clk, unless
1060 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1062 * If clk is NULL then returns 0.
1064 long clk_get_accuracy(struct clk *clk)
1066 unsigned long accuracy;
1069 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1070 __clk_recalc_accuracies(clk);
1072 accuracy = __clk_get_accuracy(clk);
1073 clk_prepare_unlock();
1077 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1079 static unsigned long clk_recalc(struct clk *clk, unsigned long parent_rate)
1081 if (clk->ops->recalc_rate)
1082 return clk->ops->recalc_rate(clk->hw, parent_rate);
1087 * __clk_recalc_rates
1088 * @clk: first clk in the subtree
1089 * @msg: notification type (see include/linux/clk.h)
1091 * Walks the subtree of clks starting with clk and recalculates rates as it
1092 * goes. Note that if a clk does not implement the .recalc_rate callback then
1093 * it is assumed that the clock will take on the rate of its parent.
1095 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1098 * Caller must hold prepare_lock.
1100 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
1102 unsigned long old_rate;
1103 unsigned long parent_rate = 0;
1106 old_rate = clk->rate;
1109 parent_rate = clk->parent->rate;
1111 clk->rate = clk_recalc(clk, parent_rate);
1114 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1115 * & ABORT_RATE_CHANGE notifiers
1117 if (clk->notifier_count && msg)
1118 __clk_notify(clk, msg, old_rate, clk->rate);
1120 hlist_for_each_entry(child, &clk->children, child_node)
1121 __clk_recalc_rates(child, msg);
1125 * clk_get_rate - return the rate of clk
1126 * @clk: the clk whose rate is being returned
1128 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1129 * is set, which means a recalc_rate will be issued.
1130 * If clk is NULL then returns 0.
1132 unsigned long clk_get_rate(struct clk *clk)
1138 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1139 __clk_recalc_rates(clk, 0);
1141 rate = __clk_get_rate(clk);
1142 clk_prepare_unlock();
1146 EXPORT_SYMBOL_GPL(clk_get_rate);
1148 static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1152 if (!clk->parents) {
1153 clk->parents = kcalloc(clk->num_parents,
1154 sizeof(struct clk *), GFP_KERNEL);
1160 * find index of new parent clock using cached parent ptrs,
1161 * or if not yet cached, use string name comparison and cache
1162 * them now to avoid future calls to __clk_lookup.
1164 for (i = 0; i < clk->num_parents; i++) {
1165 if (clk->parents[i] == parent)
1168 if (clk->parents[i])
1171 if (!strcmp(clk->parent_names[i], parent->name)) {
1172 clk->parents[i] = __clk_lookup(parent->name);
1180 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1182 hlist_del(&clk->child_node);
1185 /* avoid duplicate POST_RATE_CHANGE notifications */
1186 if (new_parent->new_child == clk)
1187 new_parent->new_child = NULL;
1189 hlist_add_head(&clk->child_node, &new_parent->children);
1191 hlist_add_head(&clk->child_node, &clk_orphan_list);
1194 clk->parent = new_parent;
1197 static struct clk *__clk_set_parent_before(struct clk *clk, struct clk *parent)
1199 unsigned long flags;
1200 struct clk *old_parent = clk->parent;
1203 * Migrate prepare state between parents and prevent race with
1206 * If the clock is not prepared, then a race with
1207 * clk_enable/disable() is impossible since we already have the
1208 * prepare lock (future calls to clk_enable() need to be preceded by
1211 * If the clock is prepared, migrate the prepared state to the new
1212 * parent and also protect against a race with clk_enable() by
1213 * forcing the clock and the new parent on. This ensures that all
1214 * future calls to clk_enable() are practically NOPs with respect to
1215 * hardware and software states.
1217 * See also: Comment for clk_set_parent() below.
1219 if (clk->prepare_count) {
1220 __clk_prepare(parent);
1225 /* update the clk tree topology */
1226 flags = clk_enable_lock();
1227 clk_reparent(clk, parent);
1228 clk_enable_unlock(flags);
1233 static void __clk_set_parent_after(struct clk *clk, struct clk *parent,
1234 struct clk *old_parent)
1237 * Finish the migration of prepare state and undo the changes done
1238 * for preventing a race with clk_enable().
1240 if (clk->prepare_count) {
1242 clk_disable(old_parent);
1243 __clk_unprepare(old_parent);
1247 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1249 unsigned long flags;
1251 struct clk *old_parent;
1253 old_parent = __clk_set_parent_before(clk, parent);
1255 /* change clock input source */
1256 if (parent && clk->ops->set_parent)
1257 ret = clk->ops->set_parent(clk->hw, p_index);
1260 flags = clk_enable_lock();
1261 clk_reparent(clk, old_parent);
1262 clk_enable_unlock(flags);
1264 if (clk->prepare_count) {
1266 clk_disable(parent);
1267 __clk_unprepare(parent);
1272 __clk_set_parent_after(clk, parent, old_parent);
1278 * __clk_speculate_rates
1279 * @clk: first clk in the subtree
1280 * @parent_rate: the "future" rate of clk's parent
1282 * Walks the subtree of clks starting with clk, speculating rates as it
1283 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1285 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1286 * pre-rate change notifications and returns early if no clks in the
1287 * subtree have subscribed to the notifications. Note that if a clk does not
1288 * implement the .recalc_rate callback then it is assumed that the clock will
1289 * take on the rate of its parent.
1291 * Caller must hold prepare_lock.
1293 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1296 unsigned long new_rate;
1297 int ret = NOTIFY_DONE;
1299 new_rate = clk_recalc(clk, parent_rate);
1301 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1302 if (clk->notifier_count)
1303 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1305 if (ret & NOTIFY_STOP_MASK) {
1306 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1307 __func__, clk->name, ret);
1311 hlist_for_each_entry(child, &clk->children, child_node) {
1312 ret = __clk_speculate_rates(child, new_rate);
1313 if (ret & NOTIFY_STOP_MASK)
1321 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1322 struct clk *new_parent, u8 p_index)
1326 clk->new_rate = new_rate;
1327 clk->new_parent = new_parent;
1328 clk->new_parent_index = p_index;
1329 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1330 clk->new_child = NULL;
1331 if (new_parent && new_parent != clk->parent)
1332 new_parent->new_child = clk;
1334 hlist_for_each_entry(child, &clk->children, child_node) {
1335 child->new_rate = clk_recalc(child, new_rate);
1336 clk_calc_subtree(child, child->new_rate, NULL, 0);
1341 * calculate the new rates returning the topmost clock that has to be
1344 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1346 struct clk *top = clk;
1347 struct clk *old_parent, *parent;
1348 unsigned long best_parent_rate = 0;
1349 unsigned long new_rate;
1353 if (IS_ERR_OR_NULL(clk))
1356 /* save parent rate, if it exists */
1357 parent = old_parent = clk->parent;
1359 best_parent_rate = parent->rate;
1361 /* find the closest rate and parent clk/rate */
1362 if (clk->ops->determine_rate) {
1363 new_rate = clk->ops->determine_rate(clk->hw, rate,
1366 } else if (clk->ops->round_rate) {
1367 new_rate = clk->ops->round_rate(clk->hw, rate,
1369 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1370 /* pass-through clock without adjustable parent */
1371 clk->new_rate = clk->rate;
1374 /* pass-through clock with adjustable parent */
1375 top = clk_calc_new_rates(parent, rate);
1376 new_rate = parent->new_rate;
1380 /* some clocks must be gated to change parent */
1381 if (parent != old_parent &&
1382 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1383 pr_debug("%s: %s not gated but wants to reparent\n",
1384 __func__, clk->name);
1388 /* try finding the new parent index */
1390 p_index = clk_fetch_parent_index(clk, parent);
1392 pr_debug("%s: clk %s can not be parent of clk %s\n",
1393 __func__, parent->name, clk->name);
1398 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1399 best_parent_rate != parent->rate)
1400 top = clk_calc_new_rates(parent, best_parent_rate);
1403 clk_calc_subtree(clk, new_rate, parent, p_index);
1409 * Notify about rate changes in a subtree. Always walk down the whole tree
1410 * so that in case of an error we can walk down the whole tree again and
1413 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1415 struct clk *child, *tmp_clk, *fail_clk = NULL;
1416 int ret = NOTIFY_DONE;
1418 if (clk->rate == clk->new_rate)
1421 if (clk->notifier_count) {
1422 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1423 if (ret & NOTIFY_STOP_MASK)
1427 hlist_for_each_entry(child, &clk->children, child_node) {
1428 /* Skip children who will be reparented to another clock */
1429 if (child->new_parent && child->new_parent != clk)
1431 tmp_clk = clk_propagate_rate_change(child, event);
1436 /* handle the new child who might not be in clk->children yet */
1437 if (clk->new_child) {
1438 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1447 * walk down a subtree and set the new rates notifying the rate
1450 static void clk_change_rate(struct clk *clk)
1453 struct hlist_node *tmp;
1454 unsigned long old_rate;
1455 unsigned long best_parent_rate = 0;
1456 bool skip_set_rate = false;
1457 struct clk *old_parent;
1459 old_rate = clk->rate;
1461 if (clk->new_parent)
1462 best_parent_rate = clk->new_parent->rate;
1463 else if (clk->parent)
1464 best_parent_rate = clk->parent->rate;
1466 if (clk->new_parent && clk->new_parent != clk->parent) {
1467 old_parent = __clk_set_parent_before(clk, clk->new_parent);
1469 if (clk->ops->set_rate_and_parent) {
1470 skip_set_rate = true;
1471 clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
1473 clk->new_parent_index);
1474 } else if (clk->ops->set_parent) {
1475 clk->ops->set_parent(clk->hw, clk->new_parent_index);
1478 __clk_set_parent_after(clk, clk->new_parent, old_parent);
1481 if (!skip_set_rate && clk->ops->set_rate)
1482 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1484 clk->rate = clk_recalc(clk, best_parent_rate);
1486 if (clk->notifier_count && old_rate != clk->rate)
1487 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1490 * Use safe iteration, as change_rate can actually swap parents
1491 * for certain clock types.
1493 hlist_for_each_entry_safe(child, tmp, &clk->children, child_node) {
1494 /* Skip children who will be reparented to another clock */
1495 if (child->new_parent && child->new_parent != clk)
1497 clk_change_rate(child);
1500 /* handle the new child who might not be in clk->children yet */
1502 clk_change_rate(clk->new_child);
1506 * clk_set_rate - specify a new rate for clk
1507 * @clk: the clk whose rate is being changed
1508 * @rate: the new rate for clk
1510 * In the simplest case clk_set_rate will only adjust the rate of clk.
1512 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1513 * propagate up to clk's parent; whether or not this happens depends on the
1514 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1515 * after calling .round_rate then upstream parent propagation is ignored. If
1516 * *parent_rate comes back with a new rate for clk's parent then we propagate
1517 * up to clk's parent and set its rate. Upward propagation will continue
1518 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1519 * .round_rate stops requesting changes to clk's parent_rate.
1521 * Rate changes are accomplished via tree traversal that also recalculates the
1522 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1524 * Returns 0 on success, -EERROR otherwise.
1526 int clk_set_rate(struct clk *clk, unsigned long rate)
1528 struct clk *top, *fail_clk;
1534 /* prevent racing with updates to the clock topology */
1537 /* bail early if nothing to do */
1538 if (rate == clk_get_rate(clk))
1541 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1546 /* calculate new rates and get the topmost changed clock */
1547 top = clk_calc_new_rates(clk, rate);
1553 /* notify that we are about to change rates */
1554 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1556 pr_debug("%s: failed to set %s rate\n", __func__,
1558 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1563 /* change the rates */
1564 clk_change_rate(top);
1567 clk_prepare_unlock();
1571 EXPORT_SYMBOL_GPL(clk_set_rate);
1574 * clk_get_parent - return the parent of a clk
1575 * @clk: the clk whose parent gets returned
1577 * Simply returns clk->parent. Returns NULL if clk is NULL.
1579 struct clk *clk_get_parent(struct clk *clk)
1584 parent = __clk_get_parent(clk);
1585 clk_prepare_unlock();
1589 EXPORT_SYMBOL_GPL(clk_get_parent);
1592 * .get_parent is mandatory for clocks with multiple possible parents. It is
1593 * optional for single-parent clocks. Always call .get_parent if it is
1594 * available and WARN if it is missing for multi-parent clocks.
1596 * For single-parent clocks without .get_parent, first check to see if the
1597 * .parents array exists, and if so use it to avoid an expensive tree
1598 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1600 static struct clk *__clk_init_parent(struct clk *clk)
1602 struct clk *ret = NULL;
1605 /* handle the trivial cases */
1607 if (!clk->num_parents)
1610 if (clk->num_parents == 1) {
1611 if (IS_ERR_OR_NULL(clk->parent))
1612 clk->parent = __clk_lookup(clk->parent_names[0]);
1617 if (!clk->ops->get_parent) {
1618 WARN(!clk->ops->get_parent,
1619 "%s: multi-parent clocks must implement .get_parent\n",
1625 * Do our best to cache parent clocks in clk->parents. This prevents
1626 * unnecessary and expensive calls to __clk_lookup. We don't set
1627 * clk->parent here; that is done by the calling function
1630 index = clk->ops->get_parent(clk->hw);
1634 kcalloc(clk->num_parents, sizeof(struct clk *),
1637 ret = clk_get_parent_by_index(clk, index);
1643 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1645 clk_reparent(clk, new_parent);
1646 __clk_recalc_accuracies(clk);
1647 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1651 * clk_set_parent - switch the parent of a mux clk
1652 * @clk: the mux clk whose input we are switching
1653 * @parent: the new input to clk
1655 * Re-parent clk to use parent as its new input source. If clk is in
1656 * prepared state, the clk will get enabled for the duration of this call. If
1657 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1658 * that, the reparenting is glitchy in hardware, etc), use the
1659 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1661 * After successfully changing clk's parent clk_set_parent will update the
1662 * clk topology, sysfs topology and propagate rate recalculation via
1663 * __clk_recalc_rates.
1665 * Returns 0 on success, -EERROR otherwise.
1667 int clk_set_parent(struct clk *clk, struct clk *parent)
1671 unsigned long p_rate = 0;
1676 /* verify ops for for multi-parent clks */
1677 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1680 /* prevent racing with updates to the clock topology */
1683 if (clk->parent == parent)
1686 /* check that we are allowed to re-parent if the clock is in use */
1687 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1692 /* try finding the new parent index */
1694 p_index = clk_fetch_parent_index(clk, parent);
1695 p_rate = parent->rate;
1697 pr_debug("%s: clk %s can not be parent of clk %s\n",
1698 __func__, parent->name, clk->name);
1704 /* propagate PRE_RATE_CHANGE notifications */
1705 ret = __clk_speculate_rates(clk, p_rate);
1707 /* abort if a driver objects */
1708 if (ret & NOTIFY_STOP_MASK)
1711 /* do the re-parent */
1712 ret = __clk_set_parent(clk, parent, p_index);
1714 /* propagate rate an accuracy recalculation accordingly */
1716 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1718 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1719 __clk_recalc_accuracies(clk);
1723 clk_prepare_unlock();
1727 EXPORT_SYMBOL_GPL(clk_set_parent);
1730 * clk_set_phase - adjust the phase shift of a clock signal
1731 * @clk: clock signal source
1732 * @degrees: number of degrees the signal is shifted
1734 * Shifts the phase of a clock signal by the specified
1735 * degrees. Returns 0 on success, -EERROR otherwise.
1737 * This function makes no distinction about the input or reference
1738 * signal that we adjust the clock signal phase against. For example
1739 * phase locked-loop clock signal generators we may shift phase with
1740 * respect to feedback clock signal input, but for other cases the
1741 * clock phase may be shifted with respect to some other, unspecified
1744 * Additionally the concept of phase shift does not propagate through
1745 * the clock tree hierarchy, which sets it apart from clock rates and
1746 * clock accuracy. A parent clock phase attribute does not have an
1747 * impact on the phase attribute of a child clock.
1749 int clk_set_phase(struct clk *clk, int degrees)
1756 /* sanity check degrees */
1763 if (!clk->ops->set_phase)
1766 ret = clk->ops->set_phase(clk->hw, degrees);
1769 clk->phase = degrees;
1772 clk_prepare_unlock();
1779 * clk_get_phase - return the phase shift of a clock signal
1780 * @clk: clock signal source
1782 * Returns the phase shift of a clock node in degrees, otherwise returns
1785 int clk_get_phase(struct clk *clk)
1794 clk_prepare_unlock();
1801 * __clk_init - initialize the data structures in a struct clk
1802 * @dev: device initializing this clk, placeholder for now
1803 * @clk: clk being initialized
1805 * Initializes the lists in struct clk, queries the hardware for the
1806 * parent and rate and sets them both.
1808 int __clk_init(struct device *dev, struct clk *clk)
1812 struct hlist_node *tmp2;
1819 /* check to see if a clock with this name is already registered */
1820 if (__clk_lookup(clk->name)) {
1821 pr_debug("%s: clk %s already initialized\n",
1822 __func__, clk->name);
1827 /* check that clk_ops are sane. See Documentation/clk.txt */
1828 if (clk->ops->set_rate &&
1829 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1830 clk->ops->recalc_rate)) {
1831 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1832 __func__, clk->name);
1837 if (clk->ops->set_parent && !clk->ops->get_parent) {
1838 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1839 __func__, clk->name);
1844 if (clk->ops->set_rate_and_parent &&
1845 !(clk->ops->set_parent && clk->ops->set_rate)) {
1846 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
1847 __func__, clk->name);
1852 /* throw a WARN if any entries in parent_names are NULL */
1853 for (i = 0; i < clk->num_parents; i++)
1854 WARN(!clk->parent_names[i],
1855 "%s: invalid NULL in %s's .parent_names\n",
1856 __func__, clk->name);
1859 * Allocate an array of struct clk *'s to avoid unnecessary string
1860 * look-ups of clk's possible parents. This can fail for clocks passed
1861 * in to clk_init during early boot; thus any access to clk->parents[]
1862 * must always check for a NULL pointer and try to populate it if
1865 * If clk->parents is not NULL we skip this entire block. This allows
1866 * for clock drivers to statically initialize clk->parents.
1868 if (clk->num_parents > 1 && !clk->parents) {
1869 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
1872 * __clk_lookup returns NULL for parents that have not been
1873 * clk_init'd; thus any access to clk->parents[] must check
1874 * for a NULL pointer. We can always perform lazy lookups for
1875 * missing parents later on.
1878 for (i = 0; i < clk->num_parents; i++)
1880 __clk_lookup(clk->parent_names[i]);
1883 clk->parent = __clk_init_parent(clk);
1886 * Populate clk->parent if parent has already been __clk_init'd. If
1887 * parent has not yet been __clk_init'd then place clk in the orphan
1888 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1891 * Every time a new clk is clk_init'd then we walk the list of orphan
1892 * clocks and re-parent any that are children of the clock currently
1896 hlist_add_head(&clk->child_node,
1897 &clk->parent->children);
1898 else if (clk->flags & CLK_IS_ROOT)
1899 hlist_add_head(&clk->child_node, &clk_root_list);
1901 hlist_add_head(&clk->child_node, &clk_orphan_list);
1904 * Set clk's accuracy. The preferred method is to use
1905 * .recalc_accuracy. For simple clocks and lazy developers the default
1906 * fallback is to use the parent's accuracy. If a clock doesn't have a
1907 * parent (or is orphaned) then accuracy is set to zero (perfect
1910 if (clk->ops->recalc_accuracy)
1911 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1912 __clk_get_accuracy(clk->parent));
1913 else if (clk->parent)
1914 clk->accuracy = clk->parent->accuracy;
1920 * Since a phase is by definition relative to its parent, just
1921 * query the current clock phase, or just assume it's in phase.
1923 if (clk->ops->get_phase)
1924 clk->phase = clk->ops->get_phase(clk->hw);
1929 * Set clk's rate. The preferred method is to use .recalc_rate. For
1930 * simple clocks and lazy developers the default fallback is to use the
1931 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1932 * then rate is set to zero.
1934 if (clk->ops->recalc_rate)
1935 clk->rate = clk->ops->recalc_rate(clk->hw,
1936 __clk_get_rate(clk->parent));
1937 else if (clk->parent)
1938 clk->rate = clk->parent->rate;
1942 clk_debug_register(clk);
1944 * walk the list of orphan clocks and reparent any that are children of
1947 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1948 if (orphan->num_parents && orphan->ops->get_parent) {
1949 i = orphan->ops->get_parent(orphan->hw);
1950 if (!strcmp(clk->name, orphan->parent_names[i]))
1951 __clk_reparent(orphan, clk);
1955 for (i = 0; i < orphan->num_parents; i++)
1956 if (!strcmp(clk->name, orphan->parent_names[i])) {
1957 __clk_reparent(orphan, clk);
1963 * optional platform-specific magic
1965 * The .init callback is not used by any of the basic clock types, but
1966 * exists for weird hardware that must perform initialization magic.
1967 * Please consider other ways of solving initialization problems before
1968 * using this callback, as its use is discouraged.
1971 clk->ops->init(clk->hw);
1973 kref_init(&clk->ref);
1975 clk_prepare_unlock();
1981 * __clk_register - register a clock and return a cookie.
1983 * Same as clk_register, except that the .clk field inside hw shall point to a
1984 * preallocated (generally statically allocated) struct clk. None of the fields
1985 * of the struct clk need to be initialized.
1987 * The data pointed to by .init and .clk field shall NOT be marked as init
1990 * __clk_register is only exposed via clk-private.h and is intended for use with
1991 * very large numbers of clocks that need to be statically initialized. It is
1992 * a layering violation to include clk-private.h from any code which implements
1993 * a clock's .ops; as such any statically initialized clock data MUST be in a
1994 * separate C file from the logic that implements its operations. Returns 0
1995 * on success, otherwise an error code.
1997 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
2003 clk->name = hw->init->name;
2004 clk->ops = hw->init->ops;
2006 clk->flags = hw->init->flags;
2007 clk->parent_names = hw->init->parent_names;
2008 clk->num_parents = hw->init->num_parents;
2009 if (dev && dev->driver)
2010 clk->owner = dev->driver->owner;
2014 ret = __clk_init(dev, clk);
2016 return ERR_PTR(ret);
2020 EXPORT_SYMBOL_GPL(__clk_register);
2023 * clk_register - allocate a new clock, register it and return an opaque cookie
2024 * @dev: device that is registering this clock
2025 * @hw: link to hardware-specific clock data
2027 * clk_register is the primary interface for populating the clock tree with new
2028 * clock nodes. It returns a pointer to the newly allocated struct clk which
2029 * cannot be dereferenced by driver code but may be used in conjuction with the
2030 * rest of the clock API. In the event of an error clk_register will return an
2031 * error code; drivers must test for an error code after calling clk_register.
2033 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
2038 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2040 pr_err("%s: could not allocate clk\n", __func__);
2045 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
2047 pr_err("%s: could not allocate clk->name\n", __func__);
2051 clk->ops = hw->init->ops;
2052 if (dev && dev->driver)
2053 clk->owner = dev->driver->owner;
2055 clk->flags = hw->init->flags;
2056 clk->num_parents = hw->init->num_parents;
2059 /* allocate local copy in case parent_names is __initdata */
2060 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
2063 if (!clk->parent_names) {
2064 pr_err("%s: could not allocate clk->parent_names\n", __func__);
2066 goto fail_parent_names;
2070 /* copy each string name in case parent_names is __initdata */
2071 for (i = 0; i < clk->num_parents; i++) {
2072 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
2074 if (!clk->parent_names[i]) {
2075 pr_err("%s: could not copy parent_names\n", __func__);
2077 goto fail_parent_names_copy;
2081 ret = __clk_init(dev, clk);
2085 fail_parent_names_copy:
2087 kfree(clk->parent_names[i]);
2088 kfree(clk->parent_names);
2094 return ERR_PTR(ret);
2096 EXPORT_SYMBOL_GPL(clk_register);
2099 * Free memory allocated for a clock.
2100 * Caller must hold prepare_lock.
2102 static void __clk_release(struct kref *ref)
2104 struct clk *clk = container_of(ref, struct clk, ref);
2105 int i = clk->num_parents;
2107 kfree(clk->parents);
2109 kfree(clk->parent_names[i]);
2111 kfree(clk->parent_names);
2117 * Empty clk_ops for unregistered clocks. These are used temporarily
2118 * after clk_unregister() was called on a clock and until last clock
2119 * consumer calls clk_put() and the struct clk object is freed.
2121 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2126 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2131 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2132 unsigned long parent_rate)
2137 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2142 static const struct clk_ops clk_nodrv_ops = {
2143 .enable = clk_nodrv_prepare_enable,
2144 .disable = clk_nodrv_disable_unprepare,
2145 .prepare = clk_nodrv_prepare_enable,
2146 .unprepare = clk_nodrv_disable_unprepare,
2147 .set_rate = clk_nodrv_set_rate,
2148 .set_parent = clk_nodrv_set_parent,
2152 * clk_unregister - unregister a currently registered clock
2153 * @clk: clock to unregister
2155 void clk_unregister(struct clk *clk)
2157 unsigned long flags;
2159 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2162 clk_debug_unregister(clk);
2166 if (clk->ops == &clk_nodrv_ops) {
2167 pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
2171 * Assign empty clock ops for consumers that might still hold
2172 * a reference to this clock.
2174 flags = clk_enable_lock();
2175 clk->ops = &clk_nodrv_ops;
2176 clk_enable_unlock(flags);
2178 if (!hlist_empty(&clk->children)) {
2180 struct hlist_node *t;
2182 /* Reparent all children to the orphan list. */
2183 hlist_for_each_entry_safe(child, t, &clk->children, child_node)
2184 clk_set_parent(child, NULL);
2187 hlist_del_init(&clk->child_node);
2189 if (clk->prepare_count)
2190 pr_warn("%s: unregistering prepared clock: %s\n",
2191 __func__, clk->name);
2192 kref_put(&clk->ref, __clk_release);
2194 clk_prepare_unlock();
2196 EXPORT_SYMBOL_GPL(clk_unregister);
2198 static void devm_clk_release(struct device *dev, void *res)
2200 clk_unregister(*(struct clk **)res);
2204 * devm_clk_register - resource managed clk_register()
2205 * @dev: device that is registering this clock
2206 * @hw: link to hardware-specific clock data
2208 * Managed clk_register(). Clocks returned from this function are
2209 * automatically clk_unregister()ed on driver detach. See clk_register() for
2212 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2217 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2219 return ERR_PTR(-ENOMEM);
2221 clk = clk_register(dev, hw);
2224 devres_add(dev, clkp);
2231 EXPORT_SYMBOL_GPL(devm_clk_register);
2233 static int devm_clk_match(struct device *dev, void *res, void *data)
2235 struct clk *c = res;
2242 * devm_clk_unregister - resource managed clk_unregister()
2243 * @clk: clock to unregister
2245 * Deallocate a clock allocated with devm_clk_register(). Normally
2246 * this function will not need to be called and the resource management
2247 * code will ensure that the resource is freed.
2249 void devm_clk_unregister(struct device *dev, struct clk *clk)
2251 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2253 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2258 int __clk_get(struct clk *clk)
2261 if (!try_module_get(clk->owner))
2264 kref_get(&clk->ref);
2269 void __clk_put(struct clk *clk)
2271 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2275 kref_put(&clk->ref, __clk_release);
2276 clk_prepare_unlock();
2278 module_put(clk->owner);
2281 /*** clk rate change notifiers ***/
2284 * clk_notifier_register - add a clk rate change notifier
2285 * @clk: struct clk * to watch
2286 * @nb: struct notifier_block * with callback info
2288 * Request notification when clk's rate changes. This uses an SRCU
2289 * notifier because we want it to block and notifier unregistrations are
2290 * uncommon. The callbacks associated with the notifier must not
2291 * re-enter into the clk framework by calling any top-level clk APIs;
2292 * this will cause a nested prepare_lock mutex.
2294 * In all notification cases cases (pre, post and abort rate change) the
2295 * original clock rate is passed to the callback via struct
2296 * clk_notifier_data.old_rate and the new frequency is passed via struct
2297 * clk_notifier_data.new_rate.
2299 * clk_notifier_register() must be called from non-atomic context.
2300 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2301 * allocation failure; otherwise, passes along the return value of
2302 * srcu_notifier_chain_register().
2304 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2306 struct clk_notifier *cn;
2314 /* search the list of notifiers for this clk */
2315 list_for_each_entry(cn, &clk_notifier_list, node)
2319 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2320 if (cn->clk != clk) {
2321 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2326 srcu_init_notifier_head(&cn->notifier_head);
2328 list_add(&cn->node, &clk_notifier_list);
2331 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2333 clk->notifier_count++;
2336 clk_prepare_unlock();
2340 EXPORT_SYMBOL_GPL(clk_notifier_register);
2343 * clk_notifier_unregister - remove a clk rate change notifier
2344 * @clk: struct clk *
2345 * @nb: struct notifier_block * with callback info
2347 * Request no further notification for changes to 'clk' and frees memory
2348 * allocated in clk_notifier_register.
2350 * Returns -EINVAL if called with null arguments; otherwise, passes
2351 * along the return value of srcu_notifier_chain_unregister().
2353 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2355 struct clk_notifier *cn = NULL;
2363 list_for_each_entry(cn, &clk_notifier_list, node)
2367 if (cn->clk == clk) {
2368 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2370 clk->notifier_count--;
2372 /* XXX the notifier code should handle this better */
2373 if (!cn->notifier_head.head) {
2374 srcu_cleanup_notifier_head(&cn->notifier_head);
2375 list_del(&cn->node);
2383 clk_prepare_unlock();
2387 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2391 * struct of_clk_provider - Clock provider registration structure
2392 * @link: Entry in global list of clock providers
2393 * @node: Pointer to device tree node of clock provider
2394 * @get: Get clock callback. Returns NULL or a struct clk for the
2395 * given clock specifier
2396 * @data: context pointer to be passed into @get callback
2398 struct of_clk_provider {
2399 struct list_head link;
2401 struct device_node *node;
2402 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2406 static const struct of_device_id __clk_of_table_sentinel
2407 __used __section(__clk_of_table_end);
2409 static LIST_HEAD(of_clk_providers);
2410 static DEFINE_MUTEX(of_clk_mutex);
2412 /* of_clk_provider list locking helpers */
2413 void of_clk_lock(void)
2415 mutex_lock(&of_clk_mutex);
2418 void of_clk_unlock(void)
2420 mutex_unlock(&of_clk_mutex);
2423 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2428 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2430 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2432 struct clk_onecell_data *clk_data = data;
2433 unsigned int idx = clkspec->args[0];
2435 if (idx >= clk_data->clk_num) {
2436 pr_err("%s: invalid clock index %d\n", __func__, idx);
2437 return ERR_PTR(-EINVAL);
2440 return clk_data->clks[idx];
2442 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2445 * of_clk_add_provider() - Register a clock provider for a node
2446 * @np: Device node pointer associated with clock provider
2447 * @clk_src_get: callback for decoding clock
2448 * @data: context pointer for @clk_src_get callback.
2450 int of_clk_add_provider(struct device_node *np,
2451 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2455 struct of_clk_provider *cp;
2458 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2462 cp->node = of_node_get(np);
2464 cp->get = clk_src_get;
2466 mutex_lock(&of_clk_mutex);
2467 list_add(&cp->link, &of_clk_providers);
2468 mutex_unlock(&of_clk_mutex);
2469 pr_debug("Added clock from %s\n", np->full_name);
2471 ret = of_clk_set_defaults(np, true);
2473 of_clk_del_provider(np);
2477 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2480 * of_clk_del_provider() - Remove a previously registered clock provider
2481 * @np: Device node pointer associated with clock provider
2483 void of_clk_del_provider(struct device_node *np)
2485 struct of_clk_provider *cp;
2487 mutex_lock(&of_clk_mutex);
2488 list_for_each_entry(cp, &of_clk_providers, link) {
2489 if (cp->node == np) {
2490 list_del(&cp->link);
2491 of_node_put(cp->node);
2496 mutex_unlock(&of_clk_mutex);
2498 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2500 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec)
2502 struct of_clk_provider *provider;
2503 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2505 /* Check if we have such a provider in our array */
2506 list_for_each_entry(provider, &of_clk_providers, link) {
2507 if (provider->node == clkspec->np)
2508 clk = provider->get(clkspec, provider->data);
2516 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2520 mutex_lock(&of_clk_mutex);
2521 clk = __of_clk_get_from_provider(clkspec);
2522 mutex_unlock(&of_clk_mutex);
2527 int of_clk_get_parent_count(struct device_node *np)
2529 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2531 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2533 const char *of_clk_get_parent_name(struct device_node *np, int index)
2535 struct of_phandle_args clkspec;
2536 struct property *prop;
2537 const char *clk_name;
2546 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2551 index = clkspec.args_count ? clkspec.args[0] : 0;
2554 /* if there is an indices property, use it to transfer the index
2555 * specified into an array offset for the clock-output-names property.
2557 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
2565 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2568 clk_name = clkspec.np->name;
2570 of_node_put(clkspec.np);
2573 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2575 struct clock_provider {
2576 of_clk_init_cb_t clk_init_cb;
2577 struct device_node *np;
2578 struct list_head node;
2581 static LIST_HEAD(clk_provider_list);
2584 * This function looks for a parent clock. If there is one, then it
2585 * checks that the provider for this parent clock was initialized, in
2586 * this case the parent clock will be ready.
2588 static int parent_ready(struct device_node *np)
2593 struct clk *clk = of_clk_get(np, i);
2595 /* this parent is ready we can check the next one */
2602 /* at least one parent is not ready, we exit now */
2603 if (PTR_ERR(clk) == -EPROBE_DEFER)
2607 * Here we make assumption that the device tree is
2608 * written correctly. So an error means that there is
2609 * no more parent. As we didn't exit yet, then the
2610 * previous parent are ready. If there is no clock
2611 * parent, no need to wait for them, then we can
2612 * consider their absence as being ready
2619 * of_clk_init() - Scan and init clock providers from the DT
2620 * @matches: array of compatible values and init functions for providers.
2622 * This function scans the device tree for matching clock providers
2623 * and calls their initialization functions. It also does it by trying
2624 * to follow the dependencies.
2626 void __init of_clk_init(const struct of_device_id *matches)
2628 const struct of_device_id *match;
2629 struct device_node *np;
2630 struct clock_provider *clk_provider, *next;
2635 matches = &__clk_of_table;
2637 /* First prepare the list of the clocks providers */
2638 for_each_matching_node_and_match(np, matches, &match) {
2639 struct clock_provider *parent =
2640 kzalloc(sizeof(struct clock_provider), GFP_KERNEL);
2642 parent->clk_init_cb = match->data;
2644 list_add_tail(&parent->node, &clk_provider_list);
2647 while (!list_empty(&clk_provider_list)) {
2648 is_init_done = false;
2649 list_for_each_entry_safe(clk_provider, next,
2650 &clk_provider_list, node) {
2651 if (force || parent_ready(clk_provider->np)) {
2653 clk_provider->clk_init_cb(clk_provider->np);
2654 of_clk_set_defaults(clk_provider->np, true);
2656 list_del(&clk_provider->node);
2657 kfree(clk_provider);
2658 is_init_done = true;
2663 * We didn't manage to initialize any of the
2664 * remaining providers during the last loop, so now we
2665 * initialize all the remaining ones unconditionally
2666 * in case the clock parent was not mandatory