2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
12 #include <linux/clk-private.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock.h>
16 #include <linux/err.h>
17 #include <linux/list.h>
18 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
26 static DEFINE_SPINLOCK(enable_lock);
27 static DEFINE_MUTEX(prepare_lock);
29 static struct task_struct *prepare_owner;
30 static struct task_struct *enable_owner;
32 static int prepare_refcnt;
33 static int enable_refcnt;
35 static HLIST_HEAD(clk_root_list);
36 static HLIST_HEAD(clk_orphan_list);
37 static LIST_HEAD(clk_notifier_list);
40 static void clk_prepare_lock(void)
42 if (!mutex_trylock(&prepare_lock)) {
43 if (prepare_owner == current) {
47 mutex_lock(&prepare_lock);
49 WARN_ON_ONCE(prepare_owner != NULL);
50 WARN_ON_ONCE(prepare_refcnt != 0);
51 prepare_owner = current;
55 static void clk_prepare_unlock(void)
57 WARN_ON_ONCE(prepare_owner != current);
58 WARN_ON_ONCE(prepare_refcnt == 0);
63 mutex_unlock(&prepare_lock);
66 static unsigned long clk_enable_lock(void)
70 if (!spin_trylock_irqsave(&enable_lock, flags)) {
71 if (enable_owner == current) {
75 spin_lock_irqsave(&enable_lock, flags);
77 WARN_ON_ONCE(enable_owner != NULL);
78 WARN_ON_ONCE(enable_refcnt != 0);
79 enable_owner = current;
84 static void clk_enable_unlock(unsigned long flags)
86 WARN_ON_ONCE(enable_owner != current);
87 WARN_ON_ONCE(enable_refcnt == 0);
92 spin_unlock_irqrestore(&enable_lock, flags);
95 /*** debugfs support ***/
97 #ifdef CONFIG_DEBUG_FS
98 #include <linux/debugfs.h>
100 static struct dentry *rootdir;
101 static struct dentry *orphandir;
102 static int inited = 0;
104 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
109 seq_printf(s, "%*s%-*s %-11d %-12d %-10lu %-11lu",
111 30 - level * 3, c->name,
112 c->enable_count, c->prepare_count, clk_get_rate(c),
113 clk_get_accuracy(c));
117 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
125 clk_summary_show_one(s, c, level);
127 hlist_for_each_entry(child, &c->children, child_node)
128 clk_summary_show_subtree(s, child, level + 1);
131 static int clk_summary_show(struct seq_file *s, void *data)
135 seq_printf(s, " clock enable_cnt prepare_cnt rate accuracy\n");
136 seq_printf(s, "---------------------------------------------------------------------------------\n");
140 hlist_for_each_entry(c, &clk_root_list, child_node)
141 clk_summary_show_subtree(s, c, 0);
143 hlist_for_each_entry(c, &clk_orphan_list, child_node)
144 clk_summary_show_subtree(s, c, 0);
146 clk_prepare_unlock();
152 static int clk_summary_open(struct inode *inode, struct file *file)
154 return single_open(file, clk_summary_show, inode->i_private);
157 static const struct file_operations clk_summary_fops = {
158 .open = clk_summary_open,
161 .release = single_release,
164 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
169 seq_printf(s, "\"%s\": { ", c->name);
170 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
171 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
172 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
173 seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
176 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
183 clk_dump_one(s, c, level);
185 hlist_for_each_entry(child, &c->children, child_node) {
187 clk_dump_subtree(s, child, level + 1);
193 static int clk_dump(struct seq_file *s, void *data)
196 bool first_node = true;
202 hlist_for_each_entry(c, &clk_root_list, child_node) {
206 clk_dump_subtree(s, c, 0);
209 hlist_for_each_entry(c, &clk_orphan_list, child_node) {
211 clk_dump_subtree(s, c, 0);
214 clk_prepare_unlock();
221 static int clk_dump_open(struct inode *inode, struct file *file)
223 return single_open(file, clk_dump, inode->i_private);
226 static const struct file_operations clk_dump_fops = {
227 .open = clk_dump_open,
230 .release = single_release,
233 /* caller must hold prepare_lock */
234 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
239 if (!clk || !pdentry) {
244 d = debugfs_create_dir(clk->name, pdentry);
250 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
255 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
256 (u32 *)&clk->accuracy);
260 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
265 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
266 (u32 *)&clk->prepare_count);
270 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
271 (u32 *)&clk->enable_count);
275 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
276 (u32 *)&clk->notifier_count);
284 debugfs_remove_recursive(clk->dentry);
290 /* caller must hold prepare_lock */
291 static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
296 if (!clk || !pdentry)
299 ret = clk_debug_create_one(clk, pdentry);
304 hlist_for_each_entry(child, &clk->children, child_node)
305 clk_debug_create_subtree(child, clk->dentry);
313 * clk_debug_register - add a clk node to the debugfs clk tree
314 * @clk: the clk being added to the debugfs clk tree
316 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
317 * initialized. Otherwise it bails out early since the debugfs clk tree
318 * will be created lazily by clk_debug_init as part of a late_initcall.
320 * Caller must hold prepare_lock. Only clk_init calls this function (so
321 * far) so this is taken care.
323 static int clk_debug_register(struct clk *clk)
326 struct dentry *pdentry;
332 parent = clk->parent;
335 * Check to see if a clk is a root clk. Also check that it is
336 * safe to add this clk to debugfs
339 if (clk->flags & CLK_IS_ROOT)
345 pdentry = parent->dentry;
349 ret = clk_debug_create_subtree(clk, pdentry);
356 * clk_debug_unregister - remove a clk node from the debugfs clk tree
357 * @clk: the clk being removed from the debugfs clk tree
359 * Dynamically removes a clk and all it's children clk nodes from the
360 * debugfs clk tree if clk->dentry points to debugfs created by
361 * clk_debug_register in __clk_init.
363 * Caller must hold prepare_lock.
365 static void clk_debug_unregister(struct clk *clk)
367 debugfs_remove_recursive(clk->dentry);
371 * clk_debug_reparent - reparent clk node in the debugfs clk tree
372 * @clk: the clk being reparented
373 * @new_parent: the new clk parent, may be NULL
375 * Rename clk entry in the debugfs clk tree if debugfs has been
376 * initialized. Otherwise it bails out early since the debugfs clk tree
377 * will be created lazily by clk_debug_init as part of a late_initcall.
379 * Caller must hold prepare_lock.
381 static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
384 struct dentry *new_parent_d;
390 new_parent_d = new_parent->dentry;
392 new_parent_d = orphandir;
394 d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
395 new_parent_d, clk->name);
399 pr_debug("%s: failed to rename debugfs entry for %s\n",
400 __func__, clk->name);
404 * clk_debug_init - lazily create the debugfs clk tree visualization
406 * clks are often initialized very early during boot before memory can
407 * be dynamically allocated and well before debugfs is setup.
408 * clk_debug_init walks the clk tree hierarchy while holding
409 * prepare_lock and creates the topology as part of a late_initcall,
410 * thus insuring that clks initialized very early will still be
411 * represented in the debugfs clk tree. This function should only be
412 * called once at boot-time, and all other clks added dynamically will
413 * be done so with clk_debug_register.
415 static int __init clk_debug_init(void)
420 rootdir = debugfs_create_dir("clk", NULL);
425 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
430 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
435 orphandir = debugfs_create_dir("orphans", rootdir);
442 hlist_for_each_entry(clk, &clk_root_list, child_node)
443 clk_debug_create_subtree(clk, rootdir);
445 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
446 clk_debug_create_subtree(clk, orphandir);
450 clk_prepare_unlock();
454 late_initcall(clk_debug_init);
456 static inline int clk_debug_register(struct clk *clk) { return 0; }
457 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
460 static inline void clk_debug_unregister(struct clk *clk)
465 /* caller must hold prepare_lock */
466 static void clk_unprepare_unused_subtree(struct clk *clk)
473 hlist_for_each_entry(child, &clk->children, child_node)
474 clk_unprepare_unused_subtree(child);
476 if (clk->prepare_count)
479 if (clk->flags & CLK_IGNORE_UNUSED)
482 if (__clk_is_prepared(clk)) {
483 if (clk->ops->unprepare_unused)
484 clk->ops->unprepare_unused(clk->hw);
485 else if (clk->ops->unprepare)
486 clk->ops->unprepare(clk->hw);
490 /* caller must hold prepare_lock */
491 static void clk_disable_unused_subtree(struct clk *clk)
499 hlist_for_each_entry(child, &clk->children, child_node)
500 clk_disable_unused_subtree(child);
502 flags = clk_enable_lock();
504 if (clk->enable_count)
507 if (clk->flags & CLK_IGNORE_UNUSED)
511 * some gate clocks have special needs during the disable-unused
512 * sequence. call .disable_unused if available, otherwise fall
515 if (__clk_is_enabled(clk)) {
516 if (clk->ops->disable_unused)
517 clk->ops->disable_unused(clk->hw);
518 else if (clk->ops->disable)
519 clk->ops->disable(clk->hw);
523 clk_enable_unlock(flags);
529 static bool clk_ignore_unused;
530 static int __init clk_ignore_unused_setup(char *__unused)
532 clk_ignore_unused = true;
535 __setup("clk_ignore_unused", clk_ignore_unused_setup);
537 static int clk_disable_unused(void)
541 if (clk_ignore_unused) {
542 pr_warn("clk: Not disabling unused clocks\n");
548 hlist_for_each_entry(clk, &clk_root_list, child_node)
549 clk_disable_unused_subtree(clk);
551 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
552 clk_disable_unused_subtree(clk);
554 hlist_for_each_entry(clk, &clk_root_list, child_node)
555 clk_unprepare_unused_subtree(clk);
557 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
558 clk_unprepare_unused_subtree(clk);
560 clk_prepare_unlock();
564 late_initcall_sync(clk_disable_unused);
566 /*** helper functions ***/
568 const char *__clk_get_name(struct clk *clk)
570 return !clk ? NULL : clk->name;
572 EXPORT_SYMBOL_GPL(__clk_get_name);
574 struct clk_hw *__clk_get_hw(struct clk *clk)
576 return !clk ? NULL : clk->hw;
579 u8 __clk_get_num_parents(struct clk *clk)
581 return !clk ? 0 : clk->num_parents;
584 struct clk *__clk_get_parent(struct clk *clk)
586 return !clk ? NULL : clk->parent;
589 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
591 if (!clk || index >= clk->num_parents)
593 else if (!clk->parents)
594 return __clk_lookup(clk->parent_names[index]);
595 else if (!clk->parents[index])
596 return clk->parents[index] =
597 __clk_lookup(clk->parent_names[index]);
599 return clk->parents[index];
602 unsigned int __clk_get_enable_count(struct clk *clk)
604 return !clk ? 0 : clk->enable_count;
607 unsigned int __clk_get_prepare_count(struct clk *clk)
609 return !clk ? 0 : clk->prepare_count;
612 unsigned long __clk_get_rate(struct clk *clk)
623 if (clk->flags & CLK_IS_ROOT)
633 unsigned long __clk_get_accuracy(struct clk *clk)
638 return clk->accuracy;
641 unsigned long __clk_get_flags(struct clk *clk)
643 return !clk ? 0 : clk->flags;
645 EXPORT_SYMBOL_GPL(__clk_get_flags);
647 bool __clk_is_prepared(struct clk *clk)
655 * .is_prepared is optional for clocks that can prepare
656 * fall back to software usage counter if it is missing
658 if (!clk->ops->is_prepared) {
659 ret = clk->prepare_count ? 1 : 0;
663 ret = clk->ops->is_prepared(clk->hw);
668 bool __clk_is_enabled(struct clk *clk)
676 * .is_enabled is only mandatory for clocks that gate
677 * fall back to software usage counter if .is_enabled is missing
679 if (!clk->ops->is_enabled) {
680 ret = clk->enable_count ? 1 : 0;
684 ret = clk->ops->is_enabled(clk->hw);
689 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
694 if (!strcmp(clk->name, name))
697 hlist_for_each_entry(child, &clk->children, child_node) {
698 ret = __clk_lookup_subtree(name, child);
706 struct clk *__clk_lookup(const char *name)
708 struct clk *root_clk;
714 /* search the 'proper' clk tree first */
715 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
716 ret = __clk_lookup_subtree(name, root_clk);
721 /* if not found, then search the orphan tree */
722 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
723 ret = __clk_lookup_subtree(name, root_clk);
732 * Helper for finding best parent to provide a given frequency. This can be used
733 * directly as a determine_rate callback (e.g. for a mux), or from a more
734 * complex clock that may combine a mux with other operations.
736 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
737 unsigned long *best_parent_rate,
738 struct clk **best_parent_p)
740 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
742 unsigned long parent_rate, best = 0;
744 /* if NO_REPARENT flag set, pass through to current parent */
745 if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
746 parent = clk->parent;
747 if (clk->flags & CLK_SET_RATE_PARENT)
748 best = __clk_round_rate(parent, rate);
750 best = __clk_get_rate(parent);
752 best = __clk_get_rate(clk);
756 /* find the parent that can provide the fastest rate <= rate */
757 num_parents = clk->num_parents;
758 for (i = 0; i < num_parents; i++) {
759 parent = clk_get_parent_by_index(clk, i);
762 if (clk->flags & CLK_SET_RATE_PARENT)
763 parent_rate = __clk_round_rate(parent, rate);
765 parent_rate = __clk_get_rate(parent);
766 if (parent_rate <= rate && parent_rate > best) {
767 best_parent = parent;
774 *best_parent_p = best_parent;
775 *best_parent_rate = best;
782 void __clk_unprepare(struct clk *clk)
787 if (WARN_ON(clk->prepare_count == 0))
790 if (--clk->prepare_count > 0)
793 WARN_ON(clk->enable_count > 0);
795 if (clk->ops->unprepare)
796 clk->ops->unprepare(clk->hw);
798 __clk_unprepare(clk->parent);
802 * clk_unprepare - undo preparation of a clock source
803 * @clk: the clk being unprepared
805 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
806 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
807 * if the operation may sleep. One example is a clk which is accessed over
808 * I2c. In the complex case a clk gate operation may require a fast and a slow
809 * part. It is this reason that clk_unprepare and clk_disable are not mutually
810 * exclusive. In fact clk_disable must be called before clk_unprepare.
812 void clk_unprepare(struct clk *clk)
815 __clk_unprepare(clk);
816 clk_prepare_unlock();
818 EXPORT_SYMBOL_GPL(clk_unprepare);
820 int __clk_prepare(struct clk *clk)
827 if (clk->prepare_count == 0) {
828 ret = __clk_prepare(clk->parent);
832 if (clk->ops->prepare) {
833 ret = clk->ops->prepare(clk->hw);
835 __clk_unprepare(clk->parent);
841 clk->prepare_count++;
847 * clk_prepare - prepare a clock source
848 * @clk: the clk being prepared
850 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
851 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
852 * operation may sleep. One example is a clk which is accessed over I2c. In
853 * the complex case a clk ungate operation may require a fast and a slow part.
854 * It is this reason that clk_prepare and clk_enable are not mutually
855 * exclusive. In fact clk_prepare must be called before clk_enable.
856 * Returns 0 on success, -EERROR otherwise.
858 int clk_prepare(struct clk *clk)
863 ret = __clk_prepare(clk);
864 clk_prepare_unlock();
868 EXPORT_SYMBOL_GPL(clk_prepare);
870 static void __clk_disable(struct clk *clk)
875 if (WARN_ON(IS_ERR(clk)))
878 if (WARN_ON(clk->enable_count == 0))
881 if (--clk->enable_count > 0)
884 if (clk->ops->disable)
885 clk->ops->disable(clk->hw);
887 __clk_disable(clk->parent);
891 * clk_disable - gate a clock
892 * @clk: the clk being gated
894 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
895 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
896 * clk if the operation is fast and will never sleep. One example is a
897 * SoC-internal clk which is controlled via simple register writes. In the
898 * complex case a clk gate operation may require a fast and a slow part. It is
899 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
900 * In fact clk_disable must be called before clk_unprepare.
902 void clk_disable(struct clk *clk)
906 flags = clk_enable_lock();
908 clk_enable_unlock(flags);
910 EXPORT_SYMBOL_GPL(clk_disable);
912 static int __clk_enable(struct clk *clk)
919 if (WARN_ON(clk->prepare_count == 0))
922 if (clk->enable_count == 0) {
923 ret = __clk_enable(clk->parent);
928 if (clk->ops->enable) {
929 ret = clk->ops->enable(clk->hw);
931 __clk_disable(clk->parent);
942 * clk_enable - ungate a clock
943 * @clk: the clk being ungated
945 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
946 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
947 * if the operation will never sleep. One example is a SoC-internal clk which
948 * is controlled via simple register writes. In the complex case a clk ungate
949 * operation may require a fast and a slow part. It is this reason that
950 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
951 * must be called before clk_enable. Returns 0 on success, -EERROR
954 int clk_enable(struct clk *clk)
959 flags = clk_enable_lock();
960 ret = __clk_enable(clk);
961 clk_enable_unlock(flags);
965 EXPORT_SYMBOL_GPL(clk_enable);
968 * __clk_round_rate - round the given rate for a clk
969 * @clk: round the rate of this clock
970 * @rate: the rate which is to be rounded
972 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
974 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
976 unsigned long parent_rate = 0;
982 parent = clk->parent;
984 parent_rate = parent->rate;
986 if (clk->ops->determine_rate)
987 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
989 else if (clk->ops->round_rate)
990 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
991 else if (clk->flags & CLK_SET_RATE_PARENT)
992 return __clk_round_rate(clk->parent, rate);
998 * clk_round_rate - round the given rate for a clk
999 * @clk: the clk for which we are rounding a rate
1000 * @rate: the rate which is to be rounded
1002 * Takes in a rate as input and rounds it to a rate that the clk can actually
1003 * use which is then returned. If clk doesn't support round_rate operation
1004 * then the parent rate is returned.
1006 long clk_round_rate(struct clk *clk, unsigned long rate)
1011 ret = __clk_round_rate(clk, rate);
1012 clk_prepare_unlock();
1016 EXPORT_SYMBOL_GPL(clk_round_rate);
1019 * __clk_notify - call clk notifier chain
1020 * @clk: struct clk * that is changing rate
1021 * @msg: clk notifier type (see include/linux/clk.h)
1022 * @old_rate: old clk rate
1023 * @new_rate: new clk rate
1025 * Triggers a notifier call chain on the clk rate-change notification
1026 * for 'clk'. Passes a pointer to the struct clk and the previous
1027 * and current rates to the notifier callback. Intended to be called by
1028 * internal clock code only. Returns NOTIFY_DONE from the last driver
1029 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1030 * a driver returns that.
1032 static int __clk_notify(struct clk *clk, unsigned long msg,
1033 unsigned long old_rate, unsigned long new_rate)
1035 struct clk_notifier *cn;
1036 struct clk_notifier_data cnd;
1037 int ret = NOTIFY_DONE;
1040 cnd.old_rate = old_rate;
1041 cnd.new_rate = new_rate;
1043 list_for_each_entry(cn, &clk_notifier_list, node) {
1044 if (cn->clk == clk) {
1045 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1055 * __clk_recalc_accuracies
1056 * @clk: first clk in the subtree
1058 * Walks the subtree of clks starting with clk and recalculates accuracies as
1059 * it goes. Note that if a clk does not implement the .recalc_accuracy
1060 * callback then it is assumed that the clock will take on the accuracy of it's
1063 * Caller must hold prepare_lock.
1065 static void __clk_recalc_accuracies(struct clk *clk)
1067 unsigned long parent_accuracy = 0;
1071 parent_accuracy = clk->parent->accuracy;
1073 if (clk->ops->recalc_accuracy)
1074 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1077 clk->accuracy = parent_accuracy;
1079 hlist_for_each_entry(child, &clk->children, child_node)
1080 __clk_recalc_accuracies(child);
1084 * clk_get_accuracy - return the accuracy of clk
1085 * @clk: the clk whose accuracy is being returned
1087 * Simply returns the cached accuracy of the clk, unless
1088 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1090 * If clk is NULL then returns 0.
1092 long clk_get_accuracy(struct clk *clk)
1094 unsigned long accuracy;
1097 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1098 __clk_recalc_accuracies(clk);
1100 accuracy = __clk_get_accuracy(clk);
1101 clk_prepare_unlock();
1105 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1108 * __clk_recalc_rates
1109 * @clk: first clk in the subtree
1110 * @msg: notification type (see include/linux/clk.h)
1112 * Walks the subtree of clks starting with clk and recalculates rates as it
1113 * goes. Note that if a clk does not implement the .recalc_rate callback then
1114 * it is assumed that the clock will take on the rate of its parent.
1116 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1119 * Caller must hold prepare_lock.
1121 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
1123 unsigned long old_rate;
1124 unsigned long parent_rate = 0;
1127 old_rate = clk->rate;
1130 parent_rate = clk->parent->rate;
1132 if (clk->ops->recalc_rate)
1133 clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1135 clk->rate = parent_rate;
1138 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1139 * & ABORT_RATE_CHANGE notifiers
1141 if (clk->notifier_count && msg)
1142 __clk_notify(clk, msg, old_rate, clk->rate);
1144 hlist_for_each_entry(child, &clk->children, child_node)
1145 __clk_recalc_rates(child, msg);
1149 * clk_get_rate - return the rate of clk
1150 * @clk: the clk whose rate is being returned
1152 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1153 * is set, which means a recalc_rate will be issued.
1154 * If clk is NULL then returns 0.
1156 unsigned long clk_get_rate(struct clk *clk)
1162 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1163 __clk_recalc_rates(clk, 0);
1165 rate = __clk_get_rate(clk);
1166 clk_prepare_unlock();
1170 EXPORT_SYMBOL_GPL(clk_get_rate);
1172 static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1176 if (!clk->parents) {
1177 clk->parents = kcalloc(clk->num_parents,
1178 sizeof(struct clk *), GFP_KERNEL);
1184 * find index of new parent clock using cached parent ptrs,
1185 * or if not yet cached, use string name comparison and cache
1186 * them now to avoid future calls to __clk_lookup.
1188 for (i = 0; i < clk->num_parents; i++) {
1189 if (clk->parents[i] == parent)
1192 if (clk->parents[i])
1195 if (!strcmp(clk->parent_names[i], parent->name)) {
1196 clk->parents[i] = __clk_lookup(parent->name);
1204 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1206 hlist_del(&clk->child_node);
1209 /* avoid duplicate POST_RATE_CHANGE notifications */
1210 if (new_parent->new_child == clk)
1211 new_parent->new_child = NULL;
1213 hlist_add_head(&clk->child_node, &new_parent->children);
1215 hlist_add_head(&clk->child_node, &clk_orphan_list);
1218 clk->parent = new_parent;
1221 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1223 unsigned long flags;
1225 struct clk *old_parent = clk->parent;
1228 * Migrate prepare state between parents and prevent race with
1231 * If the clock is not prepared, then a race with
1232 * clk_enable/disable() is impossible since we already have the
1233 * prepare lock (future calls to clk_enable() need to be preceded by
1236 * If the clock is prepared, migrate the prepared state to the new
1237 * parent and also protect against a race with clk_enable() by
1238 * forcing the clock and the new parent on. This ensures that all
1239 * future calls to clk_enable() are practically NOPs with respect to
1240 * hardware and software states.
1242 * See also: Comment for clk_set_parent() below.
1244 if (clk->prepare_count) {
1245 __clk_prepare(parent);
1250 /* update the clk tree topology */
1251 flags = clk_enable_lock();
1252 clk_reparent(clk, parent);
1253 clk_enable_unlock(flags);
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);
1273 * Finish the migration of prepare state and undo the changes done
1274 * for preventing a race with clk_enable().
1276 if (clk->prepare_count) {
1278 clk_disable(old_parent);
1279 __clk_unprepare(old_parent);
1282 /* update debugfs with new clk tree topology */
1283 clk_debug_reparent(clk, parent);
1288 * __clk_speculate_rates
1289 * @clk: first clk in the subtree
1290 * @parent_rate: the "future" rate of clk's parent
1292 * Walks the subtree of clks starting with clk, speculating rates as it
1293 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1295 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1296 * pre-rate change notifications and returns early if no clks in the
1297 * subtree have subscribed to the notifications. Note that if a clk does not
1298 * implement the .recalc_rate callback then it is assumed that the clock will
1299 * take on the rate of its parent.
1301 * Caller must hold prepare_lock.
1303 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1306 unsigned long new_rate;
1307 int ret = NOTIFY_DONE;
1309 if (clk->ops->recalc_rate)
1310 new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1312 new_rate = parent_rate;
1314 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1315 if (clk->notifier_count)
1316 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1318 if (ret & NOTIFY_STOP_MASK)
1321 hlist_for_each_entry(child, &clk->children, child_node) {
1322 ret = __clk_speculate_rates(child, new_rate);
1323 if (ret & NOTIFY_STOP_MASK)
1331 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1332 struct clk *new_parent, u8 p_index)
1336 clk->new_rate = new_rate;
1337 clk->new_parent = new_parent;
1338 clk->new_parent_index = p_index;
1339 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1340 clk->new_child = NULL;
1341 if (new_parent && new_parent != clk->parent)
1342 new_parent->new_child = clk;
1344 hlist_for_each_entry(child, &clk->children, child_node) {
1345 if (child->ops->recalc_rate)
1346 child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
1348 child->new_rate = new_rate;
1349 clk_calc_subtree(child, child->new_rate, NULL, 0);
1354 * calculate the new rates returning the topmost clock that has to be
1357 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1359 struct clk *top = clk;
1360 struct clk *old_parent, *parent;
1361 unsigned long best_parent_rate = 0;
1362 unsigned long new_rate;
1366 if (IS_ERR_OR_NULL(clk))
1369 /* save parent rate, if it exists */
1370 parent = old_parent = clk->parent;
1372 best_parent_rate = parent->rate;
1374 /* find the closest rate and parent clk/rate */
1375 if (clk->ops->determine_rate) {
1376 new_rate = clk->ops->determine_rate(clk->hw, rate,
1379 } else if (clk->ops->round_rate) {
1380 new_rate = clk->ops->round_rate(clk->hw, rate,
1382 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1383 /* pass-through clock without adjustable parent */
1384 clk->new_rate = clk->rate;
1387 /* pass-through clock with adjustable parent */
1388 top = clk_calc_new_rates(parent, rate);
1389 new_rate = parent->new_rate;
1393 /* some clocks must be gated to change parent */
1394 if (parent != old_parent &&
1395 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1396 pr_debug("%s: %s not gated but wants to reparent\n",
1397 __func__, clk->name);
1401 /* try finding the new parent index */
1403 p_index = clk_fetch_parent_index(clk, parent);
1405 pr_debug("%s: clk %s can not be parent of clk %s\n",
1406 __func__, parent->name, clk->name);
1411 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1412 best_parent_rate != parent->rate)
1413 top = clk_calc_new_rates(parent, best_parent_rate);
1416 clk_calc_subtree(clk, new_rate, parent, p_index);
1422 * Notify about rate changes in a subtree. Always walk down the whole tree
1423 * so that in case of an error we can walk down the whole tree again and
1426 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1428 struct clk *child, *tmp_clk, *fail_clk = NULL;
1429 int ret = NOTIFY_DONE;
1431 if (clk->rate == clk->new_rate)
1434 if (clk->notifier_count) {
1435 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1436 if (ret & NOTIFY_STOP_MASK)
1440 hlist_for_each_entry(child, &clk->children, child_node) {
1441 /* Skip children who will be reparented to another clock */
1442 if (child->new_parent && child->new_parent != clk)
1444 tmp_clk = clk_propagate_rate_change(child, event);
1449 /* handle the new child who might not be in clk->children yet */
1450 if (clk->new_child) {
1451 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1460 * walk down a subtree and set the new rates notifying the rate
1463 static void clk_change_rate(struct clk *clk)
1466 unsigned long old_rate;
1467 unsigned long best_parent_rate = 0;
1469 old_rate = clk->rate;
1472 if (clk->new_parent && clk->new_parent != clk->parent)
1473 __clk_set_parent(clk, clk->new_parent, clk->new_parent_index);
1476 best_parent_rate = clk->parent->rate;
1478 if (clk->ops->set_rate)
1479 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1481 if (clk->ops->recalc_rate)
1482 clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
1484 clk->rate = best_parent_rate;
1486 if (clk->notifier_count && old_rate != clk->rate)
1487 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1489 hlist_for_each_entry(child, &clk->children, child_node) {
1490 /* Skip children who will be reparented to another clock */
1491 if (child->new_parent && child->new_parent != clk)
1493 clk_change_rate(child);
1496 /* handle the new child who might not be in clk->children yet */
1498 clk_change_rate(clk->new_child);
1502 * clk_set_rate - specify a new rate for clk
1503 * @clk: the clk whose rate is being changed
1504 * @rate: the new rate for clk
1506 * In the simplest case clk_set_rate will only adjust the rate of clk.
1508 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1509 * propagate up to clk's parent; whether or not this happens depends on the
1510 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1511 * after calling .round_rate then upstream parent propagation is ignored. If
1512 * *parent_rate comes back with a new rate for clk's parent then we propagate
1513 * up to clk's parent and set its rate. Upward propagation will continue
1514 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1515 * .round_rate stops requesting changes to clk's parent_rate.
1517 * Rate changes are accomplished via tree traversal that also recalculates the
1518 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1520 * Returns 0 on success, -EERROR otherwise.
1522 int clk_set_rate(struct clk *clk, unsigned long rate)
1524 struct clk *top, *fail_clk;
1530 /* prevent racing with updates to the clock topology */
1533 /* bail early if nothing to do */
1534 if (rate == clk_get_rate(clk))
1537 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1542 /* calculate new rates and get the topmost changed clock */
1543 top = clk_calc_new_rates(clk, rate);
1549 /* notify that we are about to change rates */
1550 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1552 pr_warn("%s: failed to set %s rate\n", __func__,
1554 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1559 /* change the rates */
1560 clk_change_rate(top);
1563 clk_prepare_unlock();
1567 EXPORT_SYMBOL_GPL(clk_set_rate);
1570 * clk_get_parent - return the parent of a clk
1571 * @clk: the clk whose parent gets returned
1573 * Simply returns clk->parent. Returns NULL if clk is NULL.
1575 struct clk *clk_get_parent(struct clk *clk)
1580 parent = __clk_get_parent(clk);
1581 clk_prepare_unlock();
1585 EXPORT_SYMBOL_GPL(clk_get_parent);
1588 * .get_parent is mandatory for clocks with multiple possible parents. It is
1589 * optional for single-parent clocks. Always call .get_parent if it is
1590 * available and WARN if it is missing for multi-parent clocks.
1592 * For single-parent clocks without .get_parent, first check to see if the
1593 * .parents array exists, and if so use it to avoid an expensive tree
1594 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1596 static struct clk *__clk_init_parent(struct clk *clk)
1598 struct clk *ret = NULL;
1601 /* handle the trivial cases */
1603 if (!clk->num_parents)
1606 if (clk->num_parents == 1) {
1607 if (IS_ERR_OR_NULL(clk->parent))
1608 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1613 if (!clk->ops->get_parent) {
1614 WARN(!clk->ops->get_parent,
1615 "%s: multi-parent clocks must implement .get_parent\n",
1621 * Do our best to cache parent clocks in clk->parents. This prevents
1622 * unnecessary and expensive calls to __clk_lookup. We don't set
1623 * clk->parent here; that is done by the calling function
1626 index = clk->ops->get_parent(clk->hw);
1630 kcalloc(clk->num_parents, sizeof(struct clk *),
1633 ret = clk_get_parent_by_index(clk, index);
1639 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1641 clk_reparent(clk, new_parent);
1642 clk_debug_reparent(clk, new_parent);
1643 __clk_recalc_accuracies(clk);
1644 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1648 * clk_set_parent - switch the parent of a mux clk
1649 * @clk: the mux clk whose input we are switching
1650 * @parent: the new input to clk
1652 * Re-parent clk to use parent as its new input source. If clk is in
1653 * prepared state, the clk will get enabled for the duration of this call. If
1654 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1655 * that, the reparenting is glitchy in hardware, etc), use the
1656 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1658 * After successfully changing clk's parent clk_set_parent will update the
1659 * clk topology, sysfs topology and propagate rate recalculation via
1660 * __clk_recalc_rates.
1662 * Returns 0 on success, -EERROR otherwise.
1664 int clk_set_parent(struct clk *clk, struct clk *parent)
1668 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_init - initialize the data structures in a struct clk
1731 * @dev: device initializing this clk, placeholder for now
1732 * @clk: clk being initialized
1734 * Initializes the lists in struct clk, queries the hardware for the
1735 * parent and rate and sets them both.
1737 int __clk_init(struct device *dev, struct clk *clk)
1741 struct hlist_node *tmp2;
1748 /* check to see if a clock with this name is already registered */
1749 if (__clk_lookup(clk->name)) {
1750 pr_debug("%s: clk %s already initialized\n",
1751 __func__, clk->name);
1756 /* check that clk_ops are sane. See Documentation/clk.txt */
1757 if (clk->ops->set_rate &&
1758 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1759 clk->ops->recalc_rate)) {
1760 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1761 __func__, clk->name);
1766 if (clk->ops->set_parent && !clk->ops->get_parent) {
1767 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1768 __func__, clk->name);
1773 /* throw a WARN if any entries in parent_names are NULL */
1774 for (i = 0; i < clk->num_parents; i++)
1775 WARN(!clk->parent_names[i],
1776 "%s: invalid NULL in %s's .parent_names\n",
1777 __func__, clk->name);
1780 * Allocate an array of struct clk *'s to avoid unnecessary string
1781 * look-ups of clk's possible parents. This can fail for clocks passed
1782 * in to clk_init during early boot; thus any access to clk->parents[]
1783 * must always check for a NULL pointer and try to populate it if
1786 * If clk->parents is not NULL we skip this entire block. This allows
1787 * for clock drivers to statically initialize clk->parents.
1789 if (clk->num_parents > 1 && !clk->parents) {
1790 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
1793 * __clk_lookup returns NULL for parents that have not been
1794 * clk_init'd; thus any access to clk->parents[] must check
1795 * for a NULL pointer. We can always perform lazy lookups for
1796 * missing parents later on.
1799 for (i = 0; i < clk->num_parents; i++)
1801 __clk_lookup(clk->parent_names[i]);
1804 clk->parent = __clk_init_parent(clk);
1807 * Populate clk->parent if parent has already been __clk_init'd. If
1808 * parent has not yet been __clk_init'd then place clk in the orphan
1809 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1812 * Every time a new clk is clk_init'd then we walk the list of orphan
1813 * clocks and re-parent any that are children of the clock currently
1817 hlist_add_head(&clk->child_node,
1818 &clk->parent->children);
1819 else if (clk->flags & CLK_IS_ROOT)
1820 hlist_add_head(&clk->child_node, &clk_root_list);
1822 hlist_add_head(&clk->child_node, &clk_orphan_list);
1825 * Set clk's accuracy. The preferred method is to use
1826 * .recalc_accuracy. For simple clocks and lazy developers the default
1827 * fallback is to use the parent's accuracy. If a clock doesn't have a
1828 * parent (or is orphaned) then accuracy is set to zero (perfect
1831 if (clk->ops->recalc_accuracy)
1832 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1833 __clk_get_accuracy(clk->parent));
1834 else if (clk->parent)
1835 clk->accuracy = clk->parent->accuracy;
1840 * Set clk's rate. The preferred method is to use .recalc_rate. For
1841 * simple clocks and lazy developers the default fallback is to use the
1842 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1843 * then rate is set to zero.
1845 if (clk->ops->recalc_rate)
1846 clk->rate = clk->ops->recalc_rate(clk->hw,
1847 __clk_get_rate(clk->parent));
1848 else if (clk->parent)
1849 clk->rate = clk->parent->rate;
1853 clk_debug_register(clk);
1855 * walk the list of orphan clocks and reparent any that are children of
1858 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1859 if (orphan->num_parents && orphan->ops->get_parent) {
1860 i = orphan->ops->get_parent(orphan->hw);
1861 if (!strcmp(clk->name, orphan->parent_names[i]))
1862 __clk_reparent(orphan, clk);
1866 for (i = 0; i < orphan->num_parents; i++)
1867 if (!strcmp(clk->name, orphan->parent_names[i])) {
1868 __clk_reparent(orphan, clk);
1874 * optional platform-specific magic
1876 * The .init callback is not used by any of the basic clock types, but
1877 * exists for weird hardware that must perform initialization magic.
1878 * Please consider other ways of solving initialization problems before
1879 * using this callback, as its use is discouraged.
1882 clk->ops->init(clk->hw);
1884 kref_init(&clk->ref);
1886 clk_prepare_unlock();
1892 * __clk_register - register a clock and return a cookie.
1894 * Same as clk_register, except that the .clk field inside hw shall point to a
1895 * preallocated (generally statically allocated) struct clk. None of the fields
1896 * of the struct clk need to be initialized.
1898 * The data pointed to by .init and .clk field shall NOT be marked as init
1901 * __clk_register is only exposed via clk-private.h and is intended for use with
1902 * very large numbers of clocks that need to be statically initialized. It is
1903 * a layering violation to include clk-private.h from any code which implements
1904 * a clock's .ops; as such any statically initialized clock data MUST be in a
1905 * separate C file from the logic that implements its operations. Returns 0
1906 * on success, otherwise an error code.
1908 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1914 clk->name = hw->init->name;
1915 clk->ops = hw->init->ops;
1917 clk->flags = hw->init->flags;
1918 clk->parent_names = hw->init->parent_names;
1919 clk->num_parents = hw->init->num_parents;
1920 if (dev && dev->driver)
1921 clk->owner = dev->driver->owner;
1925 ret = __clk_init(dev, clk);
1927 return ERR_PTR(ret);
1931 EXPORT_SYMBOL_GPL(__clk_register);
1933 static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
1937 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1939 pr_err("%s: could not allocate clk->name\n", __func__);
1943 clk->ops = hw->init->ops;
1944 if (dev && dev->driver)
1945 clk->owner = dev->driver->owner;
1947 clk->flags = hw->init->flags;
1948 clk->num_parents = hw->init->num_parents;
1951 /* allocate local copy in case parent_names is __initdata */
1952 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
1955 if (!clk->parent_names) {
1956 pr_err("%s: could not allocate clk->parent_names\n", __func__);
1958 goto fail_parent_names;
1962 /* copy each string name in case parent_names is __initdata */
1963 for (i = 0; i < clk->num_parents; i++) {
1964 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1966 if (!clk->parent_names[i]) {
1967 pr_err("%s: could not copy parent_names\n", __func__);
1969 goto fail_parent_names_copy;
1973 ret = __clk_init(dev, clk);
1977 fail_parent_names_copy:
1979 kfree(clk->parent_names[i]);
1980 kfree(clk->parent_names);
1988 * clk_register - allocate a new clock, register it and return an opaque cookie
1989 * @dev: device that is registering this clock
1990 * @hw: link to hardware-specific clock data
1992 * clk_register is the primary interface for populating the clock tree with new
1993 * clock nodes. It returns a pointer to the newly allocated struct clk which
1994 * cannot be dereferenced by driver code but may be used in conjuction with the
1995 * rest of the clock API. In the event of an error clk_register will return an
1996 * error code; drivers must test for an error code after calling clk_register.
1998 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
2003 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2005 pr_err("%s: could not allocate clk\n", __func__);
2010 ret = _clk_register(dev, hw, clk);
2016 return ERR_PTR(ret);
2018 EXPORT_SYMBOL_GPL(clk_register);
2021 * Free memory allocated for a clock.
2022 * Caller must hold prepare_lock.
2024 static void __clk_release(struct kref *ref)
2026 struct clk *clk = container_of(ref, struct clk, ref);
2027 int i = clk->num_parents;
2029 kfree(clk->parents);
2031 kfree(clk->parent_names[i]);
2033 kfree(clk->parent_names);
2039 * Empty clk_ops for unregistered clocks. These are used temporarily
2040 * after clk_unregister() was called on a clock and until last clock
2041 * consumer calls clk_put() and the struct clk object is freed.
2043 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2048 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2053 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2054 unsigned long parent_rate)
2059 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2064 static const struct clk_ops clk_nodrv_ops = {
2065 .enable = clk_nodrv_prepare_enable,
2066 .disable = clk_nodrv_disable_unprepare,
2067 .prepare = clk_nodrv_prepare_enable,
2068 .unprepare = clk_nodrv_disable_unprepare,
2069 .set_rate = clk_nodrv_set_rate,
2070 .set_parent = clk_nodrv_set_parent,
2074 * clk_unregister - unregister a currently registered clock
2075 * @clk: clock to unregister
2077 void clk_unregister(struct clk *clk)
2079 unsigned long flags;
2081 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2086 if (clk->ops == &clk_nodrv_ops) {
2087 pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
2091 * Assign empty clock ops for consumers that might still hold
2092 * a reference to this clock.
2094 flags = clk_enable_lock();
2095 clk->ops = &clk_nodrv_ops;
2096 clk_enable_unlock(flags);
2098 if (!hlist_empty(&clk->children)) {
2101 /* Reparent all children to the orphan list. */
2102 hlist_for_each_entry(child, &clk->children, child_node)
2103 clk_set_parent(child, NULL);
2106 clk_debug_unregister(clk);
2108 hlist_del_init(&clk->child_node);
2110 if (clk->prepare_count)
2111 pr_warn("%s: unregistering prepared clock: %s\n",
2112 __func__, clk->name);
2114 kref_put(&clk->ref, __clk_release);
2116 clk_prepare_unlock();
2118 EXPORT_SYMBOL_GPL(clk_unregister);
2120 static void devm_clk_release(struct device *dev, void *res)
2122 clk_unregister(res);
2126 * devm_clk_register - resource managed clk_register()
2127 * @dev: device that is registering this clock
2128 * @hw: link to hardware-specific clock data
2130 * Managed clk_register(). Clocks returned from this function are
2131 * automatically clk_unregister()ed on driver detach. See clk_register() for
2134 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2139 clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
2141 return ERR_PTR(-ENOMEM);
2143 ret = _clk_register(dev, hw, clk);
2145 devres_add(dev, clk);
2153 EXPORT_SYMBOL_GPL(devm_clk_register);
2155 static int devm_clk_match(struct device *dev, void *res, void *data)
2157 struct clk *c = res;
2164 * devm_clk_unregister - resource managed clk_unregister()
2165 * @clk: clock to unregister
2167 * Deallocate a clock allocated with devm_clk_register(). Normally
2168 * this function will not need to be called and the resource management
2169 * code will ensure that the resource is freed.
2171 void devm_clk_unregister(struct device *dev, struct clk *clk)
2173 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2175 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2180 int __clk_get(struct clk *clk)
2182 if (clk && !try_module_get(clk->owner))
2185 kref_get(&clk->ref);
2189 void __clk_put(struct clk *clk)
2191 if (WARN_ON_ONCE(IS_ERR(clk)))
2195 kref_put(&clk->ref, __clk_release);
2196 clk_prepare_unlock();
2199 module_put(clk->owner);
2202 /*** clk rate change notifiers ***/
2205 * clk_notifier_register - add a clk rate change notifier
2206 * @clk: struct clk * to watch
2207 * @nb: struct notifier_block * with callback info
2209 * Request notification when clk's rate changes. This uses an SRCU
2210 * notifier because we want it to block and notifier unregistrations are
2211 * uncommon. The callbacks associated with the notifier must not
2212 * re-enter into the clk framework by calling any top-level clk APIs;
2213 * this will cause a nested prepare_lock mutex.
2215 * Pre-change notifier callbacks will be passed the current, pre-change
2216 * rate of the clk via struct clk_notifier_data.old_rate. The new,
2217 * post-change rate of the clk is passed via struct
2218 * clk_notifier_data.new_rate.
2220 * Post-change notifiers will pass the now-current, post-change rate of
2221 * the clk in both struct clk_notifier_data.old_rate and struct
2222 * clk_notifier_data.new_rate.
2224 * Abort-change notifiers are effectively the opposite of pre-change
2225 * notifiers: the original pre-change clk rate is passed in via struct
2226 * clk_notifier_data.new_rate and the failed post-change rate is passed
2227 * in via struct clk_notifier_data.old_rate.
2229 * clk_notifier_register() must be called from non-atomic context.
2230 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2231 * allocation failure; otherwise, passes along the return value of
2232 * srcu_notifier_chain_register().
2234 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2236 struct clk_notifier *cn;
2244 /* search the list of notifiers for this clk */
2245 list_for_each_entry(cn, &clk_notifier_list, node)
2249 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2250 if (cn->clk != clk) {
2251 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2256 srcu_init_notifier_head(&cn->notifier_head);
2258 list_add(&cn->node, &clk_notifier_list);
2261 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2263 clk->notifier_count++;
2266 clk_prepare_unlock();
2270 EXPORT_SYMBOL_GPL(clk_notifier_register);
2273 * clk_notifier_unregister - remove a clk rate change notifier
2274 * @clk: struct clk *
2275 * @nb: struct notifier_block * with callback info
2277 * Request no further notification for changes to 'clk' and frees memory
2278 * allocated in clk_notifier_register.
2280 * Returns -EINVAL if called with null arguments; otherwise, passes
2281 * along the return value of srcu_notifier_chain_unregister().
2283 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2285 struct clk_notifier *cn = NULL;
2293 list_for_each_entry(cn, &clk_notifier_list, node)
2297 if (cn->clk == clk) {
2298 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2300 clk->notifier_count--;
2302 /* XXX the notifier code should handle this better */
2303 if (!cn->notifier_head.head) {
2304 srcu_cleanup_notifier_head(&cn->notifier_head);
2305 list_del(&cn->node);
2313 clk_prepare_unlock();
2317 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2321 * struct of_clk_provider - Clock provider registration structure
2322 * @link: Entry in global list of clock providers
2323 * @node: Pointer to device tree node of clock provider
2324 * @get: Get clock callback. Returns NULL or a struct clk for the
2325 * given clock specifier
2326 * @data: context pointer to be passed into @get callback
2328 struct of_clk_provider {
2329 struct list_head link;
2331 struct device_node *node;
2332 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2336 extern struct of_device_id __clk_of_table[];
2338 static const struct of_device_id __clk_of_table_sentinel
2339 __used __section(__clk_of_table_end);
2341 static LIST_HEAD(of_clk_providers);
2342 static DEFINE_MUTEX(of_clk_mutex);
2344 /* of_clk_provider list locking helpers */
2345 void of_clk_lock(void)
2347 mutex_lock(&of_clk_mutex);
2350 void of_clk_unlock(void)
2352 mutex_unlock(&of_clk_mutex);
2355 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2360 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2362 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2364 struct clk_onecell_data *clk_data = data;
2365 unsigned int idx = clkspec->args[0];
2367 if (idx >= clk_data->clk_num) {
2368 pr_err("%s: invalid clock index %d\n", __func__, idx);
2369 return ERR_PTR(-EINVAL);
2372 return clk_data->clks[idx];
2374 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2377 * of_clk_add_provider() - Register a clock provider for a node
2378 * @np: Device node pointer associated with clock provider
2379 * @clk_src_get: callback for decoding clock
2380 * @data: context pointer for @clk_src_get callback.
2382 int of_clk_add_provider(struct device_node *np,
2383 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2387 struct of_clk_provider *cp;
2389 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2393 cp->node = of_node_get(np);
2395 cp->get = clk_src_get;
2397 mutex_lock(&of_clk_mutex);
2398 list_add(&cp->link, &of_clk_providers);
2399 mutex_unlock(&of_clk_mutex);
2400 pr_debug("Added clock from %s\n", np->full_name);
2404 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2407 * of_clk_del_provider() - Remove a previously registered clock provider
2408 * @np: Device node pointer associated with clock provider
2410 void of_clk_del_provider(struct device_node *np)
2412 struct of_clk_provider *cp;
2414 mutex_lock(&of_clk_mutex);
2415 list_for_each_entry(cp, &of_clk_providers, link) {
2416 if (cp->node == np) {
2417 list_del(&cp->link);
2418 of_node_put(cp->node);
2423 mutex_unlock(&of_clk_mutex);
2425 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2427 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec)
2429 struct of_clk_provider *provider;
2430 struct clk *clk = ERR_PTR(-ENOENT);
2432 /* Check if we have such a provider in our array */
2433 list_for_each_entry(provider, &of_clk_providers, link) {
2434 if (provider->node == clkspec->np)
2435 clk = provider->get(clkspec, provider->data);
2443 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2447 mutex_lock(&of_clk_mutex);
2448 clk = __of_clk_get_from_provider(clkspec);
2449 mutex_unlock(&of_clk_mutex);
2454 int of_clk_get_parent_count(struct device_node *np)
2456 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2458 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2460 const char *of_clk_get_parent_name(struct device_node *np, int index)
2462 struct of_phandle_args clkspec;
2463 const char *clk_name;
2469 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2474 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2475 clkspec.args_count ? clkspec.args[0] : 0,
2477 clk_name = clkspec.np->name;
2479 of_node_put(clkspec.np);
2482 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2485 * of_clk_init() - Scan and init clock providers from the DT
2486 * @matches: array of compatible values and init functions for providers.
2488 * This function scans the device tree for matching clock providers and
2489 * calls their initialization functions
2491 void __init of_clk_init(const struct of_device_id *matches)
2493 const struct of_device_id *match;
2494 struct device_node *np;
2497 matches = __clk_of_table;
2499 for_each_matching_node_and_match(np, matches, &match) {
2500 of_clk_init_cb_t clk_init_cb = match->data;