2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
12 #include <linux/clk-private.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock.h>
16 #include <linux/err.h>
17 #include <linux/list.h>
18 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
24 static DEFINE_SPINLOCK(enable_lock);
25 static DEFINE_MUTEX(prepare_lock);
27 static struct task_struct *prepare_owner;
28 static struct task_struct *enable_owner;
30 static int prepare_refcnt;
31 static int enable_refcnt;
33 static HLIST_HEAD(clk_root_list);
34 static HLIST_HEAD(clk_orphan_list);
35 static LIST_HEAD(clk_notifier_list);
38 static void clk_prepare_lock(void)
40 if (!mutex_trylock(&prepare_lock)) {
41 if (prepare_owner == current) {
45 mutex_lock(&prepare_lock);
47 WARN_ON_ONCE(prepare_owner != NULL);
48 WARN_ON_ONCE(prepare_refcnt != 0);
49 prepare_owner = current;
53 static void clk_prepare_unlock(void)
55 WARN_ON_ONCE(prepare_owner != current);
56 WARN_ON_ONCE(prepare_refcnt == 0);
61 mutex_unlock(&prepare_lock);
64 static unsigned long clk_enable_lock(void)
68 if (!spin_trylock_irqsave(&enable_lock, flags)) {
69 if (enable_owner == current) {
73 spin_lock_irqsave(&enable_lock, flags);
75 WARN_ON_ONCE(enable_owner != NULL);
76 WARN_ON_ONCE(enable_refcnt != 0);
77 enable_owner = current;
82 static void clk_enable_unlock(unsigned long flags)
84 WARN_ON_ONCE(enable_owner != current);
85 WARN_ON_ONCE(enable_refcnt == 0);
90 spin_unlock_irqrestore(&enable_lock, flags);
93 /*** debugfs support ***/
95 #ifdef CONFIG_DEBUG_FS
96 #include <linux/debugfs.h>
98 static struct dentry *rootdir;
99 static struct dentry *orphandir;
100 static int inited = 0;
102 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
107 seq_printf(s, "%*s%-*s %-11d %-12d %-10lu %-11lu",
109 30 - level * 3, c->name,
110 c->enable_count, c->prepare_count, clk_get_rate(c),
111 clk_get_accuracy(c));
115 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
123 clk_summary_show_one(s, c, level);
125 hlist_for_each_entry(child, &c->children, child_node)
126 clk_summary_show_subtree(s, child, level + 1);
129 static int clk_summary_show(struct seq_file *s, void *data)
133 seq_printf(s, " clock enable_cnt prepare_cnt rate accuracy\n");
134 seq_printf(s, "---------------------------------------------------------------------------------\n");
138 hlist_for_each_entry(c, &clk_root_list, child_node)
139 clk_summary_show_subtree(s, c, 0);
141 hlist_for_each_entry(c, &clk_orphan_list, child_node)
142 clk_summary_show_subtree(s, c, 0);
144 clk_prepare_unlock();
150 static int clk_summary_open(struct inode *inode, struct file *file)
152 return single_open(file, clk_summary_show, inode->i_private);
155 static const struct file_operations clk_summary_fops = {
156 .open = clk_summary_open,
159 .release = single_release,
162 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
167 seq_printf(s, "\"%s\": { ", c->name);
168 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
169 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
170 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
171 seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
174 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
181 clk_dump_one(s, c, level);
183 hlist_for_each_entry(child, &c->children, child_node) {
185 clk_dump_subtree(s, child, level + 1);
191 static int clk_dump(struct seq_file *s, void *data)
194 bool first_node = true;
200 hlist_for_each_entry(c, &clk_root_list, child_node) {
204 clk_dump_subtree(s, c, 0);
207 hlist_for_each_entry(c, &clk_orphan_list, child_node) {
209 clk_dump_subtree(s, c, 0);
212 clk_prepare_unlock();
219 static int clk_dump_open(struct inode *inode, struct file *file)
221 return single_open(file, clk_dump, inode->i_private);
224 static const struct file_operations clk_dump_fops = {
225 .open = clk_dump_open,
228 .release = single_release,
231 /* caller must hold prepare_lock */
232 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
237 if (!clk || !pdentry) {
242 d = debugfs_create_dir(clk->name, pdentry);
248 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
253 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
254 (u32 *)&clk->accuracy);
258 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
263 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
264 (u32 *)&clk->prepare_count);
268 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
269 (u32 *)&clk->enable_count);
273 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
274 (u32 *)&clk->notifier_count);
282 debugfs_remove_recursive(clk->dentry);
288 /* caller must hold prepare_lock */
289 static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
294 if (!clk || !pdentry)
297 ret = clk_debug_create_one(clk, pdentry);
302 hlist_for_each_entry(child, &clk->children, child_node)
303 clk_debug_create_subtree(child, clk->dentry);
311 * clk_debug_register - add a clk node to the debugfs clk tree
312 * @clk: the clk being added to the debugfs clk tree
314 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
315 * initialized. Otherwise it bails out early since the debugfs clk tree
316 * will be created lazily by clk_debug_init as part of a late_initcall.
318 * Caller must hold prepare_lock. Only clk_init calls this function (so
319 * far) so this is taken care.
321 static int clk_debug_register(struct clk *clk)
324 struct dentry *pdentry;
330 parent = clk->parent;
333 * Check to see if a clk is a root clk. Also check that it is
334 * safe to add this clk to debugfs
337 if (clk->flags & CLK_IS_ROOT)
343 pdentry = parent->dentry;
347 ret = clk_debug_create_subtree(clk, pdentry);
354 * clk_debug_reparent - reparent clk node in the debugfs clk tree
355 * @clk: the clk being reparented
356 * @new_parent: the new clk parent, may be NULL
358 * Rename clk entry in the debugfs clk tree if debugfs has been
359 * initialized. Otherwise it bails out early since the debugfs clk tree
360 * will be created lazily by clk_debug_init as part of a late_initcall.
362 * Caller must hold prepare_lock.
364 static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
367 struct dentry *new_parent_d;
373 new_parent_d = new_parent->dentry;
375 new_parent_d = orphandir;
377 d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
378 new_parent_d, clk->name);
382 pr_debug("%s: failed to rename debugfs entry for %s\n",
383 __func__, clk->name);
387 * clk_debug_init - lazily create the debugfs clk tree visualization
389 * clks are often initialized very early during boot before memory can
390 * be dynamically allocated and well before debugfs is setup.
391 * clk_debug_init walks the clk tree hierarchy while holding
392 * prepare_lock and creates the topology as part of a late_initcall,
393 * thus insuring that clks initialized very early will still be
394 * represented in the debugfs clk tree. This function should only be
395 * called once at boot-time, and all other clks added dynamically will
396 * be done so with clk_debug_register.
398 static int __init clk_debug_init(void)
403 rootdir = debugfs_create_dir("clk", NULL);
408 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
413 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
418 orphandir = debugfs_create_dir("orphans", rootdir);
425 hlist_for_each_entry(clk, &clk_root_list, child_node)
426 clk_debug_create_subtree(clk, rootdir);
428 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
429 clk_debug_create_subtree(clk, orphandir);
433 clk_prepare_unlock();
437 late_initcall(clk_debug_init);
439 static inline int clk_debug_register(struct clk *clk) { return 0; }
440 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
445 /* caller must hold prepare_lock */
446 static void clk_unprepare_unused_subtree(struct clk *clk)
453 hlist_for_each_entry(child, &clk->children, child_node)
454 clk_unprepare_unused_subtree(child);
456 if (clk->prepare_count)
459 if (clk->flags & CLK_IGNORE_UNUSED)
462 if (__clk_is_prepared(clk)) {
463 if (clk->ops->unprepare_unused)
464 clk->ops->unprepare_unused(clk->hw);
465 else if (clk->ops->unprepare)
466 clk->ops->unprepare(clk->hw);
470 /* caller must hold prepare_lock */
471 static void clk_disable_unused_subtree(struct clk *clk)
479 hlist_for_each_entry(child, &clk->children, child_node)
480 clk_disable_unused_subtree(child);
482 flags = clk_enable_lock();
484 if (clk->enable_count)
487 if (clk->flags & CLK_IGNORE_UNUSED)
491 * some gate clocks have special needs during the disable-unused
492 * sequence. call .disable_unused if available, otherwise fall
495 if (__clk_is_enabled(clk)) {
496 if (clk->ops->disable_unused)
497 clk->ops->disable_unused(clk->hw);
498 else if (clk->ops->disable)
499 clk->ops->disable(clk->hw);
503 clk_enable_unlock(flags);
509 static bool clk_ignore_unused;
510 static int __init clk_ignore_unused_setup(char *__unused)
512 clk_ignore_unused = true;
515 __setup("clk_ignore_unused", clk_ignore_unused_setup);
517 static int clk_disable_unused(void)
521 if (clk_ignore_unused) {
522 pr_warn("clk: Not disabling unused clocks\n");
528 hlist_for_each_entry(clk, &clk_root_list, child_node)
529 clk_disable_unused_subtree(clk);
531 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
532 clk_disable_unused_subtree(clk);
534 hlist_for_each_entry(clk, &clk_root_list, child_node)
535 clk_unprepare_unused_subtree(clk);
537 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
538 clk_unprepare_unused_subtree(clk);
540 clk_prepare_unlock();
544 late_initcall_sync(clk_disable_unused);
546 /*** helper functions ***/
548 const char *__clk_get_name(struct clk *clk)
550 return !clk ? NULL : clk->name;
552 EXPORT_SYMBOL_GPL(__clk_get_name);
554 struct clk_hw *__clk_get_hw(struct clk *clk)
556 return !clk ? NULL : clk->hw;
559 u8 __clk_get_num_parents(struct clk *clk)
561 return !clk ? 0 : clk->num_parents;
564 struct clk *__clk_get_parent(struct clk *clk)
566 return !clk ? NULL : clk->parent;
569 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
571 if (!clk || index >= clk->num_parents)
573 else if (!clk->parents)
574 return __clk_lookup(clk->parent_names[index]);
575 else if (!clk->parents[index])
576 return clk->parents[index] =
577 __clk_lookup(clk->parent_names[index]);
579 return clk->parents[index];
582 unsigned int __clk_get_enable_count(struct clk *clk)
584 return !clk ? 0 : clk->enable_count;
587 unsigned int __clk_get_prepare_count(struct clk *clk)
589 return !clk ? 0 : clk->prepare_count;
592 unsigned long __clk_get_rate(struct clk *clk)
603 if (clk->flags & CLK_IS_ROOT)
613 unsigned long __clk_get_accuracy(struct clk *clk)
618 return clk->accuracy;
621 unsigned long __clk_get_flags(struct clk *clk)
623 return !clk ? 0 : clk->flags;
625 EXPORT_SYMBOL_GPL(__clk_get_flags);
627 bool __clk_is_prepared(struct clk *clk)
635 * .is_prepared is optional for clocks that can prepare
636 * fall back to software usage counter if it is missing
638 if (!clk->ops->is_prepared) {
639 ret = clk->prepare_count ? 1 : 0;
643 ret = clk->ops->is_prepared(clk->hw);
648 bool __clk_is_enabled(struct clk *clk)
656 * .is_enabled is only mandatory for clocks that gate
657 * fall back to software usage counter if .is_enabled is missing
659 if (!clk->ops->is_enabled) {
660 ret = clk->enable_count ? 1 : 0;
664 ret = clk->ops->is_enabled(clk->hw);
669 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
674 if (!strcmp(clk->name, name))
677 hlist_for_each_entry(child, &clk->children, child_node) {
678 ret = __clk_lookup_subtree(name, child);
686 struct clk *__clk_lookup(const char *name)
688 struct clk *root_clk;
694 /* search the 'proper' clk tree first */
695 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
696 ret = __clk_lookup_subtree(name, root_clk);
701 /* if not found, then search the orphan tree */
702 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
703 ret = __clk_lookup_subtree(name, root_clk);
712 * Helper for finding best parent to provide a given frequency. This can be used
713 * directly as a determine_rate callback (e.g. for a mux), or from a more
714 * complex clock that may combine a mux with other operations.
716 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
717 unsigned long *best_parent_rate,
718 struct clk **best_parent_p)
720 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
722 unsigned long parent_rate, best = 0;
724 /* if NO_REPARENT flag set, pass through to current parent */
725 if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
726 parent = clk->parent;
727 if (clk->flags & CLK_SET_RATE_PARENT)
728 best = __clk_round_rate(parent, rate);
730 best = __clk_get_rate(parent);
732 best = __clk_get_rate(clk);
736 /* find the parent that can provide the fastest rate <= rate */
737 num_parents = clk->num_parents;
738 for (i = 0; i < num_parents; i++) {
739 parent = clk_get_parent_by_index(clk, i);
742 if (clk->flags & CLK_SET_RATE_PARENT)
743 parent_rate = __clk_round_rate(parent, rate);
745 parent_rate = __clk_get_rate(parent);
746 if (parent_rate <= rate && parent_rate > best) {
747 best_parent = parent;
754 *best_parent_p = best_parent;
755 *best_parent_rate = best;
762 void __clk_unprepare(struct clk *clk)
767 if (WARN_ON(clk->prepare_count == 0))
770 if (--clk->prepare_count > 0)
773 WARN_ON(clk->enable_count > 0);
775 if (clk->ops->unprepare)
776 clk->ops->unprepare(clk->hw);
778 __clk_unprepare(clk->parent);
782 * clk_unprepare - undo preparation of a clock source
783 * @clk: the clk being unprepared
785 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
786 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
787 * if the operation may sleep. One example is a clk which is accessed over
788 * I2c. In the complex case a clk gate operation may require a fast and a slow
789 * part. It is this reason that clk_unprepare and clk_disable are not mutually
790 * exclusive. In fact clk_disable must be called before clk_unprepare.
792 void clk_unprepare(struct clk *clk)
795 __clk_unprepare(clk);
796 clk_prepare_unlock();
798 EXPORT_SYMBOL_GPL(clk_unprepare);
800 int __clk_prepare(struct clk *clk)
807 if (clk->prepare_count == 0) {
808 ret = __clk_prepare(clk->parent);
812 if (clk->ops->prepare) {
813 ret = clk->ops->prepare(clk->hw);
815 __clk_unprepare(clk->parent);
821 clk->prepare_count++;
827 * clk_prepare - prepare a clock source
828 * @clk: the clk being prepared
830 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
831 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
832 * operation may sleep. One example is a clk which is accessed over I2c. In
833 * the complex case a clk ungate operation may require a fast and a slow part.
834 * It is this reason that clk_prepare and clk_enable are not mutually
835 * exclusive. In fact clk_prepare must be called before clk_enable.
836 * Returns 0 on success, -EERROR otherwise.
838 int clk_prepare(struct clk *clk)
843 ret = __clk_prepare(clk);
844 clk_prepare_unlock();
848 EXPORT_SYMBOL_GPL(clk_prepare);
850 static void __clk_disable(struct clk *clk)
855 if (WARN_ON(IS_ERR(clk)))
858 if (WARN_ON(clk->enable_count == 0))
861 if (--clk->enable_count > 0)
864 if (clk->ops->disable)
865 clk->ops->disable(clk->hw);
867 __clk_disable(clk->parent);
871 * clk_disable - gate a clock
872 * @clk: the clk being gated
874 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
875 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
876 * clk if the operation is fast and will never sleep. One example is a
877 * SoC-internal clk which is controlled via simple register writes. In the
878 * complex case a clk gate operation may require a fast and a slow part. It is
879 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
880 * In fact clk_disable must be called before clk_unprepare.
882 void clk_disable(struct clk *clk)
886 flags = clk_enable_lock();
888 clk_enable_unlock(flags);
890 EXPORT_SYMBOL_GPL(clk_disable);
892 static int __clk_enable(struct clk *clk)
899 if (WARN_ON(clk->prepare_count == 0))
902 if (clk->enable_count == 0) {
903 ret = __clk_enable(clk->parent);
908 if (clk->ops->enable) {
909 ret = clk->ops->enable(clk->hw);
911 __clk_disable(clk->parent);
922 * clk_enable - ungate a clock
923 * @clk: the clk being ungated
925 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
926 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
927 * if the operation will never sleep. One example is a SoC-internal clk which
928 * is controlled via simple register writes. In the complex case a clk ungate
929 * operation may require a fast and a slow part. It is this reason that
930 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
931 * must be called before clk_enable. Returns 0 on success, -EERROR
934 int clk_enable(struct clk *clk)
939 flags = clk_enable_lock();
940 ret = __clk_enable(clk);
941 clk_enable_unlock(flags);
945 EXPORT_SYMBOL_GPL(clk_enable);
948 * __clk_round_rate - round the given rate for a clk
949 * @clk: round the rate of this clock
950 * @rate: the rate which is to be rounded
952 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
954 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
956 unsigned long parent_rate = 0;
962 parent = clk->parent;
964 parent_rate = parent->rate;
966 if (clk->ops->determine_rate)
967 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
969 else if (clk->ops->round_rate)
970 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
971 else if (clk->flags & CLK_SET_RATE_PARENT)
972 return __clk_round_rate(clk->parent, rate);
978 * clk_round_rate - round the given rate for a clk
979 * @clk: the clk for which we are rounding a rate
980 * @rate: the rate which is to be rounded
982 * Takes in a rate as input and rounds it to a rate that the clk can actually
983 * use which is then returned. If clk doesn't support round_rate operation
984 * then the parent rate is returned.
986 long clk_round_rate(struct clk *clk, unsigned long rate)
991 ret = __clk_round_rate(clk, rate);
992 clk_prepare_unlock();
996 EXPORT_SYMBOL_GPL(clk_round_rate);
999 * __clk_notify - call clk notifier chain
1000 * @clk: struct clk * that is changing rate
1001 * @msg: clk notifier type (see include/linux/clk.h)
1002 * @old_rate: old clk rate
1003 * @new_rate: new clk rate
1005 * Triggers a notifier call chain on the clk rate-change notification
1006 * for 'clk'. Passes a pointer to the struct clk and the previous
1007 * and current rates to the notifier callback. Intended to be called by
1008 * internal clock code only. Returns NOTIFY_DONE from the last driver
1009 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1010 * a driver returns that.
1012 static int __clk_notify(struct clk *clk, unsigned long msg,
1013 unsigned long old_rate, unsigned long new_rate)
1015 struct clk_notifier *cn;
1016 struct clk_notifier_data cnd;
1017 int ret = NOTIFY_DONE;
1020 cnd.old_rate = old_rate;
1021 cnd.new_rate = new_rate;
1023 list_for_each_entry(cn, &clk_notifier_list, node) {
1024 if (cn->clk == clk) {
1025 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1035 * __clk_recalc_accuracies
1036 * @clk: first clk in the subtree
1038 * Walks the subtree of clks starting with clk and recalculates accuracies as
1039 * it goes. Note that if a clk does not implement the .recalc_accuracy
1040 * callback then it is assumed that the clock will take on the accuracy of it's
1043 * Caller must hold prepare_lock.
1045 static void __clk_recalc_accuracies(struct clk *clk)
1047 unsigned long parent_accuracy = 0;
1051 parent_accuracy = clk->parent->accuracy;
1053 if (clk->ops->recalc_accuracy)
1054 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1057 clk->accuracy = parent_accuracy;
1059 hlist_for_each_entry(child, &clk->children, child_node)
1060 __clk_recalc_accuracies(child);
1064 * clk_get_accuracy - return the accuracy of clk
1065 * @clk: the clk whose accuracy is being returned
1067 * Simply returns the cached accuracy of the clk, unless
1068 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1070 * If clk is NULL then returns 0.
1072 long clk_get_accuracy(struct clk *clk)
1074 unsigned long accuracy;
1077 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1078 __clk_recalc_accuracies(clk);
1080 accuracy = __clk_get_accuracy(clk);
1081 clk_prepare_unlock();
1085 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1088 * __clk_recalc_rates
1089 * @clk: first clk in the subtree
1090 * @msg: notification type (see include/linux/clk.h)
1092 * Walks the subtree of clks starting with clk and recalculates rates as it
1093 * goes. Note that if a clk does not implement the .recalc_rate callback then
1094 * it is assumed that the clock will take on the rate of its parent.
1096 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1099 * Caller must hold prepare_lock.
1101 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
1103 unsigned long old_rate;
1104 unsigned long parent_rate = 0;
1107 old_rate = clk->rate;
1110 parent_rate = clk->parent->rate;
1112 if (clk->ops->recalc_rate)
1113 clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1115 clk->rate = parent_rate;
1118 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1119 * & ABORT_RATE_CHANGE notifiers
1121 if (clk->notifier_count && msg)
1122 __clk_notify(clk, msg, old_rate, clk->rate);
1124 hlist_for_each_entry(child, &clk->children, child_node)
1125 __clk_recalc_rates(child, msg);
1129 * clk_get_rate - return the rate of clk
1130 * @clk: the clk whose rate is being returned
1132 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1133 * is set, which means a recalc_rate will be issued.
1134 * If clk is NULL then returns 0.
1136 unsigned long clk_get_rate(struct clk *clk)
1142 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1143 __clk_recalc_rates(clk, 0);
1145 rate = __clk_get_rate(clk);
1146 clk_prepare_unlock();
1150 EXPORT_SYMBOL_GPL(clk_get_rate);
1152 static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1156 if (!clk->parents) {
1157 clk->parents = kcalloc(clk->num_parents,
1158 sizeof(struct clk *), GFP_KERNEL);
1164 * find index of new parent clock using cached parent ptrs,
1165 * or if not yet cached, use string name comparison and cache
1166 * them now to avoid future calls to __clk_lookup.
1168 for (i = 0; i < clk->num_parents; i++) {
1169 if (clk->parents[i] == parent)
1172 if (clk->parents[i])
1175 if (!strcmp(clk->parent_names[i], parent->name)) {
1176 clk->parents[i] = __clk_lookup(parent->name);
1184 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1186 hlist_del(&clk->child_node);
1189 /* avoid duplicate POST_RATE_CHANGE notifications */
1190 if (new_parent->new_child == clk)
1191 new_parent->new_child = NULL;
1193 hlist_add_head(&clk->child_node, &new_parent->children);
1195 hlist_add_head(&clk->child_node, &clk_orphan_list);
1198 clk->parent = new_parent;
1201 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1203 unsigned long flags;
1205 struct clk *old_parent = clk->parent;
1208 * Migrate prepare state between parents and prevent race with
1211 * If the clock is not prepared, then a race with
1212 * clk_enable/disable() is impossible since we already have the
1213 * prepare lock (future calls to clk_enable() need to be preceded by
1216 * If the clock is prepared, migrate the prepared state to the new
1217 * parent and also protect against a race with clk_enable() by
1218 * forcing the clock and the new parent on. This ensures that all
1219 * future calls to clk_enable() are practically NOPs with respect to
1220 * hardware and software states.
1222 * See also: Comment for clk_set_parent() below.
1224 if (clk->prepare_count) {
1225 __clk_prepare(parent);
1230 /* update the clk tree topology */
1231 flags = clk_enable_lock();
1232 clk_reparent(clk, parent);
1233 clk_enable_unlock(flags);
1235 /* change clock input source */
1236 if (parent && clk->ops->set_parent)
1237 ret = clk->ops->set_parent(clk->hw, p_index);
1240 flags = clk_enable_lock();
1241 clk_reparent(clk, old_parent);
1242 clk_enable_unlock(flags);
1244 if (clk->prepare_count) {
1246 clk_disable(parent);
1247 __clk_unprepare(parent);
1253 * Finish the migration of prepare state and undo the changes done
1254 * for preventing a race with clk_enable().
1256 if (clk->prepare_count) {
1258 clk_disable(old_parent);
1259 __clk_unprepare(old_parent);
1262 /* update debugfs with new clk tree topology */
1263 clk_debug_reparent(clk, parent);
1268 * __clk_speculate_rates
1269 * @clk: first clk in the subtree
1270 * @parent_rate: the "future" rate of clk's parent
1272 * Walks the subtree of clks starting with clk, speculating rates as it
1273 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1275 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1276 * pre-rate change notifications and returns early if no clks in the
1277 * subtree have subscribed to the notifications. Note that if a clk does not
1278 * implement the .recalc_rate callback then it is assumed that the clock will
1279 * take on the rate of its parent.
1281 * Caller must hold prepare_lock.
1283 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1286 unsigned long new_rate;
1287 int ret = NOTIFY_DONE;
1289 if (clk->ops->recalc_rate)
1290 new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1292 new_rate = parent_rate;
1294 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1295 if (clk->notifier_count)
1296 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1298 if (ret & NOTIFY_STOP_MASK)
1301 hlist_for_each_entry(child, &clk->children, child_node) {
1302 ret = __clk_speculate_rates(child, new_rate);
1303 if (ret & NOTIFY_STOP_MASK)
1311 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1312 struct clk *new_parent, u8 p_index)
1316 clk->new_rate = new_rate;
1317 clk->new_parent = new_parent;
1318 clk->new_parent_index = p_index;
1319 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1320 clk->new_child = NULL;
1321 if (new_parent && new_parent != clk->parent)
1322 new_parent->new_child = clk;
1324 hlist_for_each_entry(child, &clk->children, child_node) {
1325 if (child->ops->recalc_rate)
1326 child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
1328 child->new_rate = new_rate;
1329 clk_calc_subtree(child, child->new_rate, NULL, 0);
1334 * calculate the new rates returning the topmost clock that has to be
1337 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1339 struct clk *top = clk;
1340 struct clk *old_parent, *parent;
1341 unsigned long best_parent_rate = 0;
1342 unsigned long new_rate;
1346 if (IS_ERR_OR_NULL(clk))
1349 /* save parent rate, if it exists */
1350 parent = old_parent = clk->parent;
1352 best_parent_rate = parent->rate;
1354 /* find the closest rate and parent clk/rate */
1355 if (clk->ops->determine_rate) {
1356 new_rate = clk->ops->determine_rate(clk->hw, rate,
1359 } else if (clk->ops->round_rate) {
1360 new_rate = clk->ops->round_rate(clk->hw, rate,
1362 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1363 /* pass-through clock without adjustable parent */
1364 clk->new_rate = clk->rate;
1367 /* pass-through clock with adjustable parent */
1368 top = clk_calc_new_rates(parent, rate);
1369 new_rate = parent->new_rate;
1373 /* some clocks must be gated to change parent */
1374 if (parent != old_parent &&
1375 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1376 pr_debug("%s: %s not gated but wants to reparent\n",
1377 __func__, clk->name);
1381 /* try finding the new parent index */
1383 p_index = clk_fetch_parent_index(clk, parent);
1385 pr_debug("%s: clk %s can not be parent of clk %s\n",
1386 __func__, parent->name, clk->name);
1391 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1392 best_parent_rate != parent->rate)
1393 top = clk_calc_new_rates(parent, best_parent_rate);
1396 clk_calc_subtree(clk, new_rate, parent, p_index);
1402 * Notify about rate changes in a subtree. Always walk down the whole tree
1403 * so that in case of an error we can walk down the whole tree again and
1406 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1408 struct clk *child, *tmp_clk, *fail_clk = NULL;
1409 int ret = NOTIFY_DONE;
1411 if (clk->rate == clk->new_rate)
1414 if (clk->notifier_count) {
1415 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1416 if (ret & NOTIFY_STOP_MASK)
1420 hlist_for_each_entry(child, &clk->children, child_node) {
1421 /* Skip children who will be reparented to another clock */
1422 if (child->new_parent && child->new_parent != clk)
1424 tmp_clk = clk_propagate_rate_change(child, event);
1429 /* handle the new child who might not be in clk->children yet */
1430 if (clk->new_child) {
1431 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1440 * walk down a subtree and set the new rates notifying the rate
1443 static void clk_change_rate(struct clk *clk)
1446 unsigned long old_rate;
1447 unsigned long best_parent_rate = 0;
1449 old_rate = clk->rate;
1452 if (clk->new_parent && clk->new_parent != clk->parent)
1453 __clk_set_parent(clk, clk->new_parent, clk->new_parent_index);
1456 best_parent_rate = clk->parent->rate;
1458 if (clk->ops->set_rate)
1459 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1461 if (clk->ops->recalc_rate)
1462 clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
1464 clk->rate = best_parent_rate;
1466 if (clk->notifier_count && old_rate != clk->rate)
1467 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1469 hlist_for_each_entry(child, &clk->children, child_node) {
1470 /* Skip children who will be reparented to another clock */
1471 if (child->new_parent && child->new_parent != clk)
1473 clk_change_rate(child);
1476 /* handle the new child who might not be in clk->children yet */
1478 clk_change_rate(clk->new_child);
1482 * clk_set_rate - specify a new rate for clk
1483 * @clk: the clk whose rate is being changed
1484 * @rate: the new rate for clk
1486 * In the simplest case clk_set_rate will only adjust the rate of clk.
1488 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1489 * propagate up to clk's parent; whether or not this happens depends on the
1490 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1491 * after calling .round_rate then upstream parent propagation is ignored. If
1492 * *parent_rate comes back with a new rate for clk's parent then we propagate
1493 * up to clk's parent and set its rate. Upward propagation will continue
1494 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1495 * .round_rate stops requesting changes to clk's parent_rate.
1497 * Rate changes are accomplished via tree traversal that also recalculates the
1498 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1500 * Returns 0 on success, -EERROR otherwise.
1502 int clk_set_rate(struct clk *clk, unsigned long rate)
1504 struct clk *top, *fail_clk;
1510 /* prevent racing with updates to the clock topology */
1513 /* bail early if nothing to do */
1514 if (rate == clk_get_rate(clk))
1517 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1522 /* calculate new rates and get the topmost changed clock */
1523 top = clk_calc_new_rates(clk, rate);
1529 /* notify that we are about to change rates */
1530 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1532 pr_warn("%s: failed to set %s rate\n", __func__,
1534 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1539 /* change the rates */
1540 clk_change_rate(top);
1543 clk_prepare_unlock();
1547 EXPORT_SYMBOL_GPL(clk_set_rate);
1550 * clk_get_parent - return the parent of a clk
1551 * @clk: the clk whose parent gets returned
1553 * Simply returns clk->parent. Returns NULL if clk is NULL.
1555 struct clk *clk_get_parent(struct clk *clk)
1560 parent = __clk_get_parent(clk);
1561 clk_prepare_unlock();
1565 EXPORT_SYMBOL_GPL(clk_get_parent);
1568 * .get_parent is mandatory for clocks with multiple possible parents. It is
1569 * optional for single-parent clocks. Always call .get_parent if it is
1570 * available and WARN if it is missing for multi-parent clocks.
1572 * For single-parent clocks without .get_parent, first check to see if the
1573 * .parents array exists, and if so use it to avoid an expensive tree
1574 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1576 static struct clk *__clk_init_parent(struct clk *clk)
1578 struct clk *ret = NULL;
1581 /* handle the trivial cases */
1583 if (!clk->num_parents)
1586 if (clk->num_parents == 1) {
1587 if (IS_ERR_OR_NULL(clk->parent))
1588 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1593 if (!clk->ops->get_parent) {
1594 WARN(!clk->ops->get_parent,
1595 "%s: multi-parent clocks must implement .get_parent\n",
1601 * Do our best to cache parent clocks in clk->parents. This prevents
1602 * unnecessary and expensive calls to __clk_lookup. We don't set
1603 * clk->parent here; that is done by the calling function
1606 index = clk->ops->get_parent(clk->hw);
1610 kcalloc(clk->num_parents, sizeof(struct clk *),
1613 ret = clk_get_parent_by_index(clk, index);
1619 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1621 clk_reparent(clk, new_parent);
1622 clk_debug_reparent(clk, new_parent);
1623 __clk_recalc_accuracies(clk);
1624 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1628 * clk_set_parent - switch the parent of a mux clk
1629 * @clk: the mux clk whose input we are switching
1630 * @parent: the new input to clk
1632 * Re-parent clk to use parent as its new input source. If clk is in
1633 * prepared state, the clk will get enabled for the duration of this call. If
1634 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1635 * that, the reparenting is glitchy in hardware, etc), use the
1636 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1638 * After successfully changing clk's parent clk_set_parent will update the
1639 * clk topology, sysfs topology and propagate rate recalculation via
1640 * __clk_recalc_rates.
1642 * Returns 0 on success, -EERROR otherwise.
1644 int clk_set_parent(struct clk *clk, struct clk *parent)
1648 unsigned long p_rate = 0;
1656 /* verify ops for for multi-parent clks */
1657 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1660 /* prevent racing with updates to the clock topology */
1663 if (clk->parent == parent)
1666 /* check that we are allowed to re-parent if the clock is in use */
1667 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1672 /* try finding the new parent index */
1674 p_index = clk_fetch_parent_index(clk, parent);
1675 p_rate = parent->rate;
1677 pr_debug("%s: clk %s can not be parent of clk %s\n",
1678 __func__, parent->name, clk->name);
1684 /* propagate PRE_RATE_CHANGE notifications */
1685 ret = __clk_speculate_rates(clk, p_rate);
1687 /* abort if a driver objects */
1688 if (ret & NOTIFY_STOP_MASK)
1691 /* do the re-parent */
1692 ret = __clk_set_parent(clk, parent, p_index);
1694 /* propagate rate an accuracy recalculation accordingly */
1696 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1698 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1699 __clk_recalc_accuracies(clk);
1703 clk_prepare_unlock();
1707 EXPORT_SYMBOL_GPL(clk_set_parent);
1710 * __clk_init - initialize the data structures in a struct clk
1711 * @dev: device initializing this clk, placeholder for now
1712 * @clk: clk being initialized
1714 * Initializes the lists in struct clk, queries the hardware for the
1715 * parent and rate and sets them both.
1717 int __clk_init(struct device *dev, struct clk *clk)
1721 struct hlist_node *tmp2;
1728 /* check to see if a clock with this name is already registered */
1729 if (__clk_lookup(clk->name)) {
1730 pr_debug("%s: clk %s already initialized\n",
1731 __func__, clk->name);
1736 /* check that clk_ops are sane. See Documentation/clk.txt */
1737 if (clk->ops->set_rate &&
1738 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1739 clk->ops->recalc_rate)) {
1740 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1741 __func__, clk->name);
1746 if (clk->ops->set_parent && !clk->ops->get_parent) {
1747 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1748 __func__, clk->name);
1753 /* throw a WARN if any entries in parent_names are NULL */
1754 for (i = 0; i < clk->num_parents; i++)
1755 WARN(!clk->parent_names[i],
1756 "%s: invalid NULL in %s's .parent_names\n",
1757 __func__, clk->name);
1760 * Allocate an array of struct clk *'s to avoid unnecessary string
1761 * look-ups of clk's possible parents. This can fail for clocks passed
1762 * in to clk_init during early boot; thus any access to clk->parents[]
1763 * must always check for a NULL pointer and try to populate it if
1766 * If clk->parents is not NULL we skip this entire block. This allows
1767 * for clock drivers to statically initialize clk->parents.
1769 if (clk->num_parents > 1 && !clk->parents) {
1770 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
1773 * __clk_lookup returns NULL for parents that have not been
1774 * clk_init'd; thus any access to clk->parents[] must check
1775 * for a NULL pointer. We can always perform lazy lookups for
1776 * missing parents later on.
1779 for (i = 0; i < clk->num_parents; i++)
1781 __clk_lookup(clk->parent_names[i]);
1784 clk->parent = __clk_init_parent(clk);
1787 * Populate clk->parent if parent has already been __clk_init'd. If
1788 * parent has not yet been __clk_init'd then place clk in the orphan
1789 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1792 * Every time a new clk is clk_init'd then we walk the list of orphan
1793 * clocks and re-parent any that are children of the clock currently
1797 hlist_add_head(&clk->child_node,
1798 &clk->parent->children);
1799 else if (clk->flags & CLK_IS_ROOT)
1800 hlist_add_head(&clk->child_node, &clk_root_list);
1802 hlist_add_head(&clk->child_node, &clk_orphan_list);
1805 * Set clk's accuracy. The preferred method is to use
1806 * .recalc_accuracy. For simple clocks and lazy developers the default
1807 * fallback is to use the parent's accuracy. If a clock doesn't have a
1808 * parent (or is orphaned) then accuracy is set to zero (perfect
1811 if (clk->ops->recalc_accuracy)
1812 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1813 __clk_get_accuracy(clk->parent));
1814 else if (clk->parent)
1815 clk->accuracy = clk->parent->accuracy;
1820 * Set clk's rate. The preferred method is to use .recalc_rate. For
1821 * simple clocks and lazy developers the default fallback is to use the
1822 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1823 * then rate is set to zero.
1825 if (clk->ops->recalc_rate)
1826 clk->rate = clk->ops->recalc_rate(clk->hw,
1827 __clk_get_rate(clk->parent));
1828 else if (clk->parent)
1829 clk->rate = clk->parent->rate;
1833 clk_debug_register(clk);
1835 * walk the list of orphan clocks and reparent any that are children of
1838 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1839 if (orphan->num_parents && orphan->ops->get_parent) {
1840 i = orphan->ops->get_parent(orphan->hw);
1841 if (!strcmp(clk->name, orphan->parent_names[i]))
1842 __clk_reparent(orphan, clk);
1846 for (i = 0; i < orphan->num_parents; i++)
1847 if (!strcmp(clk->name, orphan->parent_names[i])) {
1848 __clk_reparent(orphan, clk);
1854 * optional platform-specific magic
1856 * The .init callback is not used by any of the basic clock types, but
1857 * exists for weird hardware that must perform initialization magic.
1858 * Please consider other ways of solving initialization problems before
1859 * using this callback, as its use is discouraged.
1862 clk->ops->init(clk->hw);
1865 clk_prepare_unlock();
1871 * __clk_register - register a clock and return a cookie.
1873 * Same as clk_register, except that the .clk field inside hw shall point to a
1874 * preallocated (generally statically allocated) struct clk. None of the fields
1875 * of the struct clk need to be initialized.
1877 * The data pointed to by .init and .clk field shall NOT be marked as init
1880 * __clk_register is only exposed via clk-private.h and is intended for use with
1881 * very large numbers of clocks that need to be statically initialized. It is
1882 * a layering violation to include clk-private.h from any code which implements
1883 * a clock's .ops; as such any statically initialized clock data MUST be in a
1884 * separate C file from the logic that implements its operations. Returns 0
1885 * on success, otherwise an error code.
1887 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1893 clk->name = hw->init->name;
1894 clk->ops = hw->init->ops;
1896 clk->flags = hw->init->flags;
1897 clk->parent_names = hw->init->parent_names;
1898 clk->num_parents = hw->init->num_parents;
1900 ret = __clk_init(dev, clk);
1902 return ERR_PTR(ret);
1906 EXPORT_SYMBOL_GPL(__clk_register);
1908 static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
1912 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1914 pr_err("%s: could not allocate clk->name\n", __func__);
1918 clk->ops = hw->init->ops;
1920 clk->flags = hw->init->flags;
1921 clk->num_parents = hw->init->num_parents;
1924 /* allocate local copy in case parent_names is __initdata */
1925 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
1928 if (!clk->parent_names) {
1929 pr_err("%s: could not allocate clk->parent_names\n", __func__);
1931 goto fail_parent_names;
1935 /* copy each string name in case parent_names is __initdata */
1936 for (i = 0; i < clk->num_parents; i++) {
1937 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1939 if (!clk->parent_names[i]) {
1940 pr_err("%s: could not copy parent_names\n", __func__);
1942 goto fail_parent_names_copy;
1946 ret = __clk_init(dev, clk);
1950 fail_parent_names_copy:
1952 kfree(clk->parent_names[i]);
1953 kfree(clk->parent_names);
1961 * clk_register - allocate a new clock, register it and return an opaque cookie
1962 * @dev: device that is registering this clock
1963 * @hw: link to hardware-specific clock data
1965 * clk_register is the primary interface for populating the clock tree with new
1966 * clock nodes. It returns a pointer to the newly allocated struct clk which
1967 * cannot be dereferenced by driver code but may be used in conjuction with the
1968 * rest of the clock API. In the event of an error clk_register will return an
1969 * error code; drivers must test for an error code after calling clk_register.
1971 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1976 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1978 pr_err("%s: could not allocate clk\n", __func__);
1983 ret = _clk_register(dev, hw, clk);
1989 return ERR_PTR(ret);
1991 EXPORT_SYMBOL_GPL(clk_register);
1994 * clk_unregister - unregister a currently registered clock
1995 * @clk: clock to unregister
1997 * Currently unimplemented.
1999 void clk_unregister(struct clk *clk) {}
2000 EXPORT_SYMBOL_GPL(clk_unregister);
2002 static void devm_clk_release(struct device *dev, void *res)
2004 clk_unregister(res);
2008 * devm_clk_register - resource managed clk_register()
2009 * @dev: device that is registering this clock
2010 * @hw: link to hardware-specific clock data
2012 * Managed clk_register(). Clocks returned from this function are
2013 * automatically clk_unregister()ed on driver detach. See clk_register() for
2016 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2021 clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
2023 return ERR_PTR(-ENOMEM);
2025 ret = _clk_register(dev, hw, clk);
2027 devres_add(dev, clk);
2035 EXPORT_SYMBOL_GPL(devm_clk_register);
2037 static int devm_clk_match(struct device *dev, void *res, void *data)
2039 struct clk *c = res;
2046 * devm_clk_unregister - resource managed clk_unregister()
2047 * @clk: clock to unregister
2049 * Deallocate a clock allocated with devm_clk_register(). Normally
2050 * this function will not need to be called and the resource management
2051 * code will ensure that the resource is freed.
2053 void devm_clk_unregister(struct device *dev, struct clk *clk)
2055 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2057 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2059 /*** clk rate change notifiers ***/
2062 * clk_notifier_register - add a clk rate change notifier
2063 * @clk: struct clk * to watch
2064 * @nb: struct notifier_block * with callback info
2066 * Request notification when clk's rate changes. This uses an SRCU
2067 * notifier because we want it to block and notifier unregistrations are
2068 * uncommon. The callbacks associated with the notifier must not
2069 * re-enter into the clk framework by calling any top-level clk APIs;
2070 * this will cause a nested prepare_lock mutex.
2072 * Pre-change notifier callbacks will be passed the current, pre-change
2073 * rate of the clk via struct clk_notifier_data.old_rate. The new,
2074 * post-change rate of the clk is passed via struct
2075 * clk_notifier_data.new_rate.
2077 * Post-change notifiers will pass the now-current, post-change rate of
2078 * the clk in both struct clk_notifier_data.old_rate and struct
2079 * clk_notifier_data.new_rate.
2081 * Abort-change notifiers are effectively the opposite of pre-change
2082 * notifiers: the original pre-change clk rate is passed in via struct
2083 * clk_notifier_data.new_rate and the failed post-change rate is passed
2084 * in via struct clk_notifier_data.old_rate.
2086 * clk_notifier_register() must be called from non-atomic context.
2087 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2088 * allocation failure; otherwise, passes along the return value of
2089 * srcu_notifier_chain_register().
2091 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2093 struct clk_notifier *cn;
2101 /* search the list of notifiers for this clk */
2102 list_for_each_entry(cn, &clk_notifier_list, node)
2106 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2107 if (cn->clk != clk) {
2108 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2113 srcu_init_notifier_head(&cn->notifier_head);
2115 list_add(&cn->node, &clk_notifier_list);
2118 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2120 clk->notifier_count++;
2123 clk_prepare_unlock();
2127 EXPORT_SYMBOL_GPL(clk_notifier_register);
2130 * clk_notifier_unregister - remove a clk rate change notifier
2131 * @clk: struct clk *
2132 * @nb: struct notifier_block * with callback info
2134 * Request no further notification for changes to 'clk' and frees memory
2135 * allocated in clk_notifier_register.
2137 * Returns -EINVAL if called with null arguments; otherwise, passes
2138 * along the return value of srcu_notifier_chain_unregister().
2140 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2142 struct clk_notifier *cn = NULL;
2150 list_for_each_entry(cn, &clk_notifier_list, node)
2154 if (cn->clk == clk) {
2155 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2157 clk->notifier_count--;
2159 /* XXX the notifier code should handle this better */
2160 if (!cn->notifier_head.head) {
2161 srcu_cleanup_notifier_head(&cn->notifier_head);
2162 list_del(&cn->node);
2170 clk_prepare_unlock();
2174 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2178 * struct of_clk_provider - Clock provider registration structure
2179 * @link: Entry in global list of clock providers
2180 * @node: Pointer to device tree node of clock provider
2181 * @get: Get clock callback. Returns NULL or a struct clk for the
2182 * given clock specifier
2183 * @data: context pointer to be passed into @get callback
2185 struct of_clk_provider {
2186 struct list_head link;
2188 struct device_node *node;
2189 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2193 extern struct of_device_id __clk_of_table[];
2195 static const struct of_device_id __clk_of_table_sentinel
2196 __used __section(__clk_of_table_end);
2198 static LIST_HEAD(of_clk_providers);
2199 static DEFINE_MUTEX(of_clk_lock);
2201 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2206 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2208 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2210 struct clk_onecell_data *clk_data = data;
2211 unsigned int idx = clkspec->args[0];
2213 if (idx >= clk_data->clk_num) {
2214 pr_err("%s: invalid clock index %d\n", __func__, idx);
2215 return ERR_PTR(-EINVAL);
2218 return clk_data->clks[idx];
2220 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2223 * of_clk_add_provider() - Register a clock provider for a node
2224 * @np: Device node pointer associated with clock provider
2225 * @clk_src_get: callback for decoding clock
2226 * @data: context pointer for @clk_src_get callback.
2228 int of_clk_add_provider(struct device_node *np,
2229 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2233 struct of_clk_provider *cp;
2235 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2239 cp->node = of_node_get(np);
2241 cp->get = clk_src_get;
2243 mutex_lock(&of_clk_lock);
2244 list_add(&cp->link, &of_clk_providers);
2245 mutex_unlock(&of_clk_lock);
2246 pr_debug("Added clock from %s\n", np->full_name);
2250 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2253 * of_clk_del_provider() - Remove a previously registered clock provider
2254 * @np: Device node pointer associated with clock provider
2256 void of_clk_del_provider(struct device_node *np)
2258 struct of_clk_provider *cp;
2260 mutex_lock(&of_clk_lock);
2261 list_for_each_entry(cp, &of_clk_providers, link) {
2262 if (cp->node == np) {
2263 list_del(&cp->link);
2264 of_node_put(cp->node);
2269 mutex_unlock(&of_clk_lock);
2271 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2273 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2275 struct of_clk_provider *provider;
2276 struct clk *clk = ERR_PTR(-ENOENT);
2278 /* Check if we have such a provider in our array */
2279 mutex_lock(&of_clk_lock);
2280 list_for_each_entry(provider, &of_clk_providers, link) {
2281 if (provider->node == clkspec->np)
2282 clk = provider->get(clkspec, provider->data);
2286 mutex_unlock(&of_clk_lock);
2291 int of_clk_get_parent_count(struct device_node *np)
2293 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2295 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2297 const char *of_clk_get_parent_name(struct device_node *np, int index)
2299 struct of_phandle_args clkspec;
2300 const char *clk_name;
2306 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2311 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2312 clkspec.args_count ? clkspec.args[0] : 0,
2314 clk_name = clkspec.np->name;
2316 of_node_put(clkspec.np);
2319 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2322 * of_clk_init() - Scan and init clock providers from the DT
2323 * @matches: array of compatible values and init functions for providers.
2325 * This function scans the device tree for matching clock providers and
2326 * calls their initialization functions
2328 void __init of_clk_init(const struct of_device_id *matches)
2330 const struct of_device_id *match;
2331 struct device_node *np;
2334 matches = __clk_of_table;
2336 for_each_matching_node_and_match(np, matches, &match) {
2337 of_clk_init_cb_t clk_init_cb = match->data;