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_COMMON_CLK_DEBUG
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",
109 30 - level * 3, c->name,
110 c->enable_count, c->prepare_count, c->rate);
114 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
122 clk_summary_show_one(s, c, level);
124 hlist_for_each_entry(child, &c->children, child_node)
125 clk_summary_show_subtree(s, child, level + 1);
128 static int clk_summary_show(struct seq_file *s, void *data)
132 seq_printf(s, " clock enable_cnt prepare_cnt rate\n");
133 seq_printf(s, "---------------------------------------------------------------------\n");
137 hlist_for_each_entry(c, &clk_root_list, child_node)
138 clk_summary_show_subtree(s, c, 0);
140 hlist_for_each_entry(c, &clk_orphan_list, child_node)
141 clk_summary_show_subtree(s, c, 0);
143 clk_prepare_unlock();
149 static int clk_summary_open(struct inode *inode, struct file *file)
151 return single_open(file, clk_summary_show, inode->i_private);
154 static const struct file_operations clk_summary_fops = {
155 .open = clk_summary_open,
158 .release = single_release,
161 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
166 seq_printf(s, "\"%s\": { ", c->name);
167 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
168 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
169 seq_printf(s, "\"rate\": %lu", c->rate);
172 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
179 clk_dump_one(s, c, level);
181 hlist_for_each_entry(child, &c->children, child_node) {
183 clk_dump_subtree(s, child, level + 1);
189 static int clk_dump(struct seq_file *s, void *data)
192 bool first_node = true;
198 hlist_for_each_entry(c, &clk_root_list, child_node) {
202 clk_dump_subtree(s, c, 0);
205 hlist_for_each_entry(c, &clk_orphan_list, child_node) {
207 clk_dump_subtree(s, c, 0);
210 clk_prepare_unlock();
217 static int clk_dump_open(struct inode *inode, struct file *file)
219 return single_open(file, clk_dump, inode->i_private);
222 static const struct file_operations clk_dump_fops = {
223 .open = clk_dump_open,
226 .release = single_release,
229 /* caller must hold prepare_lock */
230 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
235 if (!clk || !pdentry) {
240 d = debugfs_create_dir(clk->name, pdentry);
246 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
251 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
256 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
257 (u32 *)&clk->prepare_count);
261 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
262 (u32 *)&clk->enable_count);
266 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
267 (u32 *)&clk->notifier_count);
275 debugfs_remove(clk->dentry);
280 /* caller must hold prepare_lock */
281 static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
286 if (!clk || !pdentry)
289 ret = clk_debug_create_one(clk, pdentry);
294 hlist_for_each_entry(child, &clk->children, child_node)
295 clk_debug_create_subtree(child, clk->dentry);
303 * clk_debug_register - add a clk node to the debugfs clk tree
304 * @clk: the clk being added to the debugfs clk tree
306 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
307 * initialized. Otherwise it bails out early since the debugfs clk tree
308 * will be created lazily by clk_debug_init as part of a late_initcall.
310 * Caller must hold prepare_lock. Only clk_init calls this function (so
311 * far) so this is taken care.
313 static int clk_debug_register(struct clk *clk)
316 struct dentry *pdentry;
322 parent = clk->parent;
325 * Check to see if a clk is a root clk. Also check that it is
326 * safe to add this clk to debugfs
329 if (clk->flags & CLK_IS_ROOT)
335 pdentry = parent->dentry;
339 ret = clk_debug_create_subtree(clk, pdentry);
346 * clk_debug_reparent - reparent clk node in the debugfs clk tree
347 * @clk: the clk being reparented
348 * @new_parent: the new clk parent, may be NULL
350 * Rename clk entry in the debugfs clk tree if debugfs has been
351 * initialized. Otherwise it bails out early since the debugfs clk tree
352 * will be created lazily by clk_debug_init as part of a late_initcall.
354 * Caller must hold prepare_lock.
356 static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
359 struct dentry *new_parent_d;
365 new_parent_d = new_parent->dentry;
367 new_parent_d = orphandir;
369 d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
370 new_parent_d, clk->name);
374 pr_debug("%s: failed to rename debugfs entry for %s\n",
375 __func__, clk->name);
379 * clk_debug_init - lazily create the debugfs clk tree visualization
381 * clks are often initialized very early during boot before memory can
382 * be dynamically allocated and well before debugfs is setup.
383 * clk_debug_init walks the clk tree hierarchy while holding
384 * prepare_lock and creates the topology as part of a late_initcall,
385 * thus insuring that clks initialized very early will still be
386 * represented in the debugfs clk tree. This function should only be
387 * called once at boot-time, and all other clks added dynamically will
388 * be done so with clk_debug_register.
390 static int __init clk_debug_init(void)
395 rootdir = debugfs_create_dir("clk", NULL);
400 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
405 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
410 orphandir = debugfs_create_dir("orphans", rootdir);
417 hlist_for_each_entry(clk, &clk_root_list, child_node)
418 clk_debug_create_subtree(clk, rootdir);
420 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
421 clk_debug_create_subtree(clk, orphandir);
425 clk_prepare_unlock();
429 late_initcall(clk_debug_init);
431 static inline int clk_debug_register(struct clk *clk) { return 0; }
432 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
437 /* caller must hold prepare_lock */
438 static void clk_unprepare_unused_subtree(struct clk *clk)
445 hlist_for_each_entry(child, &clk->children, child_node)
446 clk_unprepare_unused_subtree(child);
448 if (clk->prepare_count)
451 if (clk->flags & CLK_IGNORE_UNUSED)
454 if (__clk_is_prepared(clk)) {
455 if (clk->ops->unprepare_unused)
456 clk->ops->unprepare_unused(clk->hw);
457 else if (clk->ops->unprepare)
458 clk->ops->unprepare(clk->hw);
461 EXPORT_SYMBOL_GPL(__clk_get_flags);
463 /* caller must hold prepare_lock */
464 static void clk_disable_unused_subtree(struct clk *clk)
472 hlist_for_each_entry(child, &clk->children, child_node)
473 clk_disable_unused_subtree(child);
475 flags = clk_enable_lock();
477 if (clk->enable_count)
480 if (clk->flags & CLK_IGNORE_UNUSED)
484 * some gate clocks have special needs during the disable-unused
485 * sequence. call .disable_unused if available, otherwise fall
488 if (__clk_is_enabled(clk)) {
489 if (clk->ops->disable_unused)
490 clk->ops->disable_unused(clk->hw);
491 else if (clk->ops->disable)
492 clk->ops->disable(clk->hw);
496 clk_enable_unlock(flags);
502 static int clk_disable_unused(void)
508 hlist_for_each_entry(clk, &clk_root_list, child_node)
509 clk_disable_unused_subtree(clk);
511 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
512 clk_disable_unused_subtree(clk);
514 hlist_for_each_entry(clk, &clk_root_list, child_node)
515 clk_unprepare_unused_subtree(clk);
517 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
518 clk_unprepare_unused_subtree(clk);
520 clk_prepare_unlock();
524 late_initcall(clk_disable_unused);
526 /*** helper functions ***/
528 const char *__clk_get_name(struct clk *clk)
530 return !clk ? NULL : clk->name;
532 EXPORT_SYMBOL_GPL(__clk_get_name);
534 struct clk_hw *__clk_get_hw(struct clk *clk)
536 return !clk ? NULL : clk->hw;
539 u8 __clk_get_num_parents(struct clk *clk)
541 return !clk ? 0 : clk->num_parents;
544 struct clk *__clk_get_parent(struct clk *clk)
546 return !clk ? NULL : clk->parent;
549 unsigned int __clk_get_enable_count(struct clk *clk)
551 return !clk ? 0 : clk->enable_count;
554 unsigned int __clk_get_prepare_count(struct clk *clk)
556 return !clk ? 0 : clk->prepare_count;
559 unsigned long __clk_get_rate(struct clk *clk)
570 if (clk->flags & CLK_IS_ROOT)
580 unsigned long __clk_get_flags(struct clk *clk)
582 return !clk ? 0 : clk->flags;
585 bool __clk_is_prepared(struct clk *clk)
593 * .is_prepared is optional for clocks that can prepare
594 * fall back to software usage counter if it is missing
596 if (!clk->ops->is_prepared) {
597 ret = clk->prepare_count ? 1 : 0;
601 ret = clk->ops->is_prepared(clk->hw);
606 bool __clk_is_enabled(struct clk *clk)
614 * .is_enabled is only mandatory for clocks that gate
615 * fall back to software usage counter if .is_enabled is missing
617 if (!clk->ops->is_enabled) {
618 ret = clk->enable_count ? 1 : 0;
622 ret = clk->ops->is_enabled(clk->hw);
627 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
632 if (!strcmp(clk->name, name))
635 hlist_for_each_entry(child, &clk->children, child_node) {
636 ret = __clk_lookup_subtree(name, child);
644 struct clk *__clk_lookup(const char *name)
646 struct clk *root_clk;
652 /* search the 'proper' clk tree first */
653 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
654 ret = __clk_lookup_subtree(name, root_clk);
659 /* if not found, then search the orphan tree */
660 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
661 ret = __clk_lookup_subtree(name, root_clk);
671 void __clk_unprepare(struct clk *clk)
676 if (WARN_ON(clk->prepare_count == 0))
679 if (--clk->prepare_count > 0)
682 WARN_ON(clk->enable_count > 0);
684 if (clk->ops->unprepare)
685 clk->ops->unprepare(clk->hw);
687 __clk_unprepare(clk->parent);
691 * clk_unprepare - undo preparation of a clock source
692 * @clk: the clk being unprepare
694 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
695 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
696 * if the operation may sleep. One example is a clk which is accessed over
697 * I2c. In the complex case a clk gate operation may require a fast and a slow
698 * part. It is this reason that clk_unprepare and clk_disable are not mutually
699 * exclusive. In fact clk_disable must be called before clk_unprepare.
701 void clk_unprepare(struct clk *clk)
704 __clk_unprepare(clk);
705 clk_prepare_unlock();
707 EXPORT_SYMBOL_GPL(clk_unprepare);
709 int __clk_prepare(struct clk *clk)
716 if (clk->prepare_count == 0) {
717 ret = __clk_prepare(clk->parent);
721 if (clk->ops->prepare) {
722 ret = clk->ops->prepare(clk->hw);
724 __clk_unprepare(clk->parent);
730 clk->prepare_count++;
736 * clk_prepare - prepare a clock source
737 * @clk: the clk being prepared
739 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
740 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
741 * operation may sleep. One example is a clk which is accessed over I2c. In
742 * the complex case a clk ungate operation may require a fast and a slow part.
743 * It is this reason that clk_prepare and clk_enable are not mutually
744 * exclusive. In fact clk_prepare must be called before clk_enable.
745 * Returns 0 on success, -EERROR otherwise.
747 int clk_prepare(struct clk *clk)
752 ret = __clk_prepare(clk);
753 clk_prepare_unlock();
757 EXPORT_SYMBOL_GPL(clk_prepare);
759 static void __clk_disable(struct clk *clk)
764 if (WARN_ON(IS_ERR(clk)))
767 if (WARN_ON(clk->enable_count == 0))
770 if (--clk->enable_count > 0)
773 if (clk->ops->disable)
774 clk->ops->disable(clk->hw);
776 __clk_disable(clk->parent);
780 * clk_disable - gate a clock
781 * @clk: the clk being gated
783 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
784 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
785 * clk if the operation is fast and will never sleep. One example is a
786 * SoC-internal clk which is controlled via simple register writes. In the
787 * complex case a clk gate operation may require a fast and a slow part. It is
788 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
789 * In fact clk_disable must be called before clk_unprepare.
791 void clk_disable(struct clk *clk)
795 flags = clk_enable_lock();
797 clk_enable_unlock(flags);
799 EXPORT_SYMBOL_GPL(clk_disable);
801 static int __clk_enable(struct clk *clk)
808 if (WARN_ON(clk->prepare_count == 0))
811 if (clk->enable_count == 0) {
812 ret = __clk_enable(clk->parent);
817 if (clk->ops->enable) {
818 ret = clk->ops->enable(clk->hw);
820 __clk_disable(clk->parent);
831 * clk_enable - ungate a clock
832 * @clk: the clk being ungated
834 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
835 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
836 * if the operation will never sleep. One example is a SoC-internal clk which
837 * is controlled via simple register writes. In the complex case a clk ungate
838 * operation may require a fast and a slow part. It is this reason that
839 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
840 * must be called before clk_enable. Returns 0 on success, -EERROR
843 int clk_enable(struct clk *clk)
848 flags = clk_enable_lock();
849 ret = __clk_enable(clk);
850 clk_enable_unlock(flags);
854 EXPORT_SYMBOL_GPL(clk_enable);
857 * __clk_round_rate - round the given rate for a clk
858 * @clk: round the rate of this clock
860 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
862 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
864 unsigned long parent_rate = 0;
869 if (!clk->ops->round_rate) {
870 if (clk->flags & CLK_SET_RATE_PARENT)
871 return __clk_round_rate(clk->parent, rate);
877 parent_rate = clk->parent->rate;
879 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
883 * clk_round_rate - round the given rate for a clk
884 * @clk: the clk for which we are rounding a rate
885 * @rate: the rate which is to be rounded
887 * Takes in a rate as input and rounds it to a rate that the clk can actually
888 * use which is then returned. If clk doesn't support round_rate operation
889 * then the parent rate is returned.
891 long clk_round_rate(struct clk *clk, unsigned long rate)
896 ret = __clk_round_rate(clk, rate);
897 clk_prepare_unlock();
901 EXPORT_SYMBOL_GPL(clk_round_rate);
904 * __clk_notify - call clk notifier chain
905 * @clk: struct clk * that is changing rate
906 * @msg: clk notifier type (see include/linux/clk.h)
907 * @old_rate: old clk rate
908 * @new_rate: new clk rate
910 * Triggers a notifier call chain on the clk rate-change notification
911 * for 'clk'. Passes a pointer to the struct clk and the previous
912 * and current rates to the notifier callback. Intended to be called by
913 * internal clock code only. Returns NOTIFY_DONE from the last driver
914 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
915 * a driver returns that.
917 static int __clk_notify(struct clk *clk, unsigned long msg,
918 unsigned long old_rate, unsigned long new_rate)
920 struct clk_notifier *cn;
921 struct clk_notifier_data cnd;
922 int ret = NOTIFY_DONE;
925 cnd.old_rate = old_rate;
926 cnd.new_rate = new_rate;
928 list_for_each_entry(cn, &clk_notifier_list, node) {
929 if (cn->clk == clk) {
930 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
941 * @clk: first clk in the subtree
942 * @msg: notification type (see include/linux/clk.h)
944 * Walks the subtree of clks starting with clk and recalculates rates as it
945 * goes. Note that if a clk does not implement the .recalc_rate callback then
946 * it is assumed that the clock will take on the rate of it's parent.
948 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
951 * Caller must hold prepare_lock.
953 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
955 unsigned long old_rate;
956 unsigned long parent_rate = 0;
959 old_rate = clk->rate;
962 parent_rate = clk->parent->rate;
964 if (clk->ops->recalc_rate)
965 clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
967 clk->rate = parent_rate;
970 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
971 * & ABORT_RATE_CHANGE notifiers
973 if (clk->notifier_count && msg)
974 __clk_notify(clk, msg, old_rate, clk->rate);
976 hlist_for_each_entry(child, &clk->children, child_node)
977 __clk_recalc_rates(child, msg);
981 * clk_get_rate - return the rate of clk
982 * @clk: the clk whose rate is being returned
984 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
985 * is set, which means a recalc_rate will be issued.
986 * If clk is NULL then returns 0.
988 unsigned long clk_get_rate(struct clk *clk)
994 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
995 __clk_recalc_rates(clk, 0);
997 rate = __clk_get_rate(clk);
998 clk_prepare_unlock();
1002 EXPORT_SYMBOL_GPL(clk_get_rate);
1005 * __clk_speculate_rates
1006 * @clk: first clk in the subtree
1007 * @parent_rate: the "future" rate of clk's parent
1009 * Walks the subtree of clks starting with clk, speculating rates as it
1010 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1012 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1013 * pre-rate change notifications and returns early if no clks in the
1014 * subtree have subscribed to the notifications. Note that if a clk does not
1015 * implement the .recalc_rate callback then it is assumed that the clock will
1016 * take on the rate of it's parent.
1018 * Caller must hold prepare_lock.
1020 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1023 unsigned long new_rate;
1024 int ret = NOTIFY_DONE;
1026 if (clk->ops->recalc_rate)
1027 new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1029 new_rate = parent_rate;
1031 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1032 if (clk->notifier_count)
1033 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1035 if (ret & NOTIFY_STOP_MASK)
1038 hlist_for_each_entry(child, &clk->children, child_node) {
1039 ret = __clk_speculate_rates(child, new_rate);
1040 if (ret & NOTIFY_STOP_MASK)
1048 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
1052 clk->new_rate = new_rate;
1054 hlist_for_each_entry(child, &clk->children, child_node) {
1055 if (child->ops->recalc_rate)
1056 child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
1058 child->new_rate = new_rate;
1059 clk_calc_subtree(child, child->new_rate);
1064 * calculate the new rates returning the topmost clock that has to be
1067 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1069 struct clk *top = clk;
1070 unsigned long best_parent_rate = 0;
1071 unsigned long new_rate;
1074 if (IS_ERR_OR_NULL(clk))
1077 /* save parent rate, if it exists */
1079 best_parent_rate = clk->parent->rate;
1081 /* never propagate up to the parent */
1082 if (!(clk->flags & CLK_SET_RATE_PARENT)) {
1083 if (!clk->ops->round_rate) {
1084 clk->new_rate = clk->rate;
1087 new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
1091 /* need clk->parent from here on out */
1093 pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
1097 if (!clk->ops->round_rate) {
1098 top = clk_calc_new_rates(clk->parent, rate);
1099 new_rate = clk->parent->new_rate;
1104 new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
1106 if (best_parent_rate != clk->parent->rate) {
1107 top = clk_calc_new_rates(clk->parent, best_parent_rate);
1113 clk_calc_subtree(clk, new_rate);
1119 * Notify about rate changes in a subtree. Always walk down the whole tree
1120 * so that in case of an error we can walk down the whole tree again and
1123 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1125 struct clk *child, *fail_clk = NULL;
1126 int ret = NOTIFY_DONE;
1128 if (clk->rate == clk->new_rate)
1131 if (clk->notifier_count) {
1132 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1133 if (ret & NOTIFY_STOP_MASK)
1137 hlist_for_each_entry(child, &clk->children, child_node) {
1138 clk = clk_propagate_rate_change(child, event);
1147 * walk down a subtree and set the new rates notifying the rate
1150 static void clk_change_rate(struct clk *clk)
1153 unsigned long old_rate;
1154 unsigned long best_parent_rate = 0;
1156 old_rate = clk->rate;
1159 best_parent_rate = clk->parent->rate;
1161 if (clk->ops->set_rate)
1162 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1164 if (clk->ops->recalc_rate)
1165 clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
1167 clk->rate = best_parent_rate;
1169 if (clk->notifier_count && old_rate != clk->rate)
1170 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1172 hlist_for_each_entry(child, &clk->children, child_node)
1173 clk_change_rate(child);
1177 * clk_set_rate - specify a new rate for clk
1178 * @clk: the clk whose rate is being changed
1179 * @rate: the new rate for clk
1181 * In the simplest case clk_set_rate will only adjust the rate of clk.
1183 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1184 * propagate up to clk's parent; whether or not this happens depends on the
1185 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1186 * after calling .round_rate then upstream parent propagation is ignored. If
1187 * *parent_rate comes back with a new rate for clk's parent then we propagate
1188 * up to clk's parent and set it's rate. Upward propagation will continue
1189 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1190 * .round_rate stops requesting changes to clk's parent_rate.
1192 * Rate changes are accomplished via tree traversal that also recalculates the
1193 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1195 * Returns 0 on success, -EERROR otherwise.
1197 int clk_set_rate(struct clk *clk, unsigned long rate)
1199 struct clk *top, *fail_clk;
1202 /* prevent racing with updates to the clock topology */
1205 /* bail early if nothing to do */
1206 if (rate == clk->rate)
1209 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1214 /* calculate new rates and get the topmost changed clock */
1215 top = clk_calc_new_rates(clk, rate);
1221 /* notify that we are about to change rates */
1222 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1224 pr_warn("%s: failed to set %s rate\n", __func__,
1226 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1231 /* change the rates */
1232 clk_change_rate(top);
1235 clk_prepare_unlock();
1239 EXPORT_SYMBOL_GPL(clk_set_rate);
1242 * clk_get_parent - return the parent of a clk
1243 * @clk: the clk whose parent gets returned
1245 * Simply returns clk->parent. Returns NULL if clk is NULL.
1247 struct clk *clk_get_parent(struct clk *clk)
1252 parent = __clk_get_parent(clk);
1253 clk_prepare_unlock();
1257 EXPORT_SYMBOL_GPL(clk_get_parent);
1260 * .get_parent is mandatory for clocks with multiple possible parents. It is
1261 * optional for single-parent clocks. Always call .get_parent if it is
1262 * available and WARN if it is missing for multi-parent clocks.
1264 * For single-parent clocks without .get_parent, first check to see if the
1265 * .parents array exists, and if so use it to avoid an expensive tree
1266 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1268 static struct clk *__clk_init_parent(struct clk *clk)
1270 struct clk *ret = NULL;
1273 /* handle the trivial cases */
1275 if (!clk->num_parents)
1278 if (clk->num_parents == 1) {
1279 if (IS_ERR_OR_NULL(clk->parent))
1280 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1285 if (!clk->ops->get_parent) {
1286 WARN(!clk->ops->get_parent,
1287 "%s: multi-parent clocks must implement .get_parent\n",
1293 * Do our best to cache parent clocks in clk->parents. This prevents
1294 * unnecessary and expensive calls to __clk_lookup. We don't set
1295 * clk->parent here; that is done by the calling function
1298 index = clk->ops->get_parent(clk->hw);
1302 kzalloc((sizeof(struct clk*) * clk->num_parents),
1306 ret = __clk_lookup(clk->parent_names[index]);
1307 else if (!clk->parents[index])
1308 ret = clk->parents[index] =
1309 __clk_lookup(clk->parent_names[index]);
1311 ret = clk->parents[index];
1317 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1319 hlist_del(&clk->child_node);
1322 hlist_add_head(&clk->child_node, &new_parent->children);
1324 hlist_add_head(&clk->child_node, &clk_orphan_list);
1326 clk->parent = new_parent;
1329 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1331 clk_reparent(clk, new_parent);
1332 clk_debug_reparent(clk, new_parent);
1333 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1336 static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1341 clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1345 * find index of new parent clock using cached parent ptrs,
1346 * or if not yet cached, use string name comparison and cache
1347 * them now to avoid future calls to __clk_lookup.
1349 for (i = 0; i < clk->num_parents; i++) {
1350 if (clk->parents && clk->parents[i] == parent)
1352 else if (!strcmp(clk->parent_names[i], parent->name)) {
1354 clk->parents[i] = __clk_lookup(parent->name);
1362 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1364 unsigned long flags;
1366 struct clk *old_parent = clk->parent;
1367 bool migrated_enable = false;
1369 /* migrate prepare */
1370 if (clk->prepare_count)
1371 __clk_prepare(parent);
1373 flags = clk_enable_lock();
1375 /* migrate enable */
1376 if (clk->enable_count) {
1377 __clk_enable(parent);
1378 migrated_enable = true;
1381 /* update the clk tree topology */
1382 clk_reparent(clk, parent);
1384 clk_enable_unlock(flags);
1386 /* change clock input source */
1387 if (parent && clk->ops->set_parent)
1388 ret = clk->ops->set_parent(clk->hw, p_index);
1392 * The error handling is tricky due to that we need to release
1393 * the spinlock while issuing the .set_parent callback. This
1394 * means the new parent might have been enabled/disabled in
1395 * between, which must be considered when doing rollback.
1397 flags = clk_enable_lock();
1399 clk_reparent(clk, old_parent);
1401 if (migrated_enable && clk->enable_count) {
1402 __clk_disable(parent);
1403 } else if (migrated_enable && (clk->enable_count == 0)) {
1404 __clk_disable(old_parent);
1405 } else if (!migrated_enable && clk->enable_count) {
1406 __clk_disable(parent);
1407 __clk_enable(old_parent);
1410 clk_enable_unlock(flags);
1412 if (clk->prepare_count)
1413 __clk_unprepare(parent);
1418 /* clean up enable for old parent if migration was done */
1419 if (migrated_enable) {
1420 flags = clk_enable_lock();
1421 __clk_disable(old_parent);
1422 clk_enable_unlock(flags);
1425 /* clean up prepare for old parent if migration was done */
1426 if (clk->prepare_count)
1427 __clk_unprepare(old_parent);
1429 /* update debugfs with new clk tree topology */
1430 clk_debug_reparent(clk, parent);
1435 * clk_set_parent - switch the parent of a mux clk
1436 * @clk: the mux clk whose input we are switching
1437 * @parent: the new input to clk
1439 * Re-parent clk to use parent as it's new input source. If clk has the
1440 * CLK_SET_PARENT_GATE flag set then clk must be gated for this
1441 * operation to succeed. After successfully changing clk's parent
1442 * clk_set_parent will update the clk topology, sysfs topology and
1443 * propagate rate recalculation via __clk_recalc_rates. Returns 0 on
1444 * success, -EERROR otherwise.
1446 int clk_set_parent(struct clk *clk, struct clk *parent)
1450 unsigned long p_rate = 0;
1452 if (!clk || !clk->ops)
1455 /* verify ops for for multi-parent clks */
1456 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1459 /* prevent racing with updates to the clock topology */
1462 if (clk->parent == parent)
1465 /* check that we are allowed to re-parent if the clock is in use */
1466 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1471 /* try finding the new parent index */
1473 p_index = clk_fetch_parent_index(clk, parent);
1474 p_rate = parent->rate;
1475 if (p_index == clk->num_parents) {
1476 pr_debug("%s: clk %s can not be parent of clk %s\n",
1477 __func__, parent->name, clk->name);
1483 /* propagate PRE_RATE_CHANGE notifications */
1484 if (clk->notifier_count)
1485 ret = __clk_speculate_rates(clk, p_rate);
1487 /* abort if a driver objects */
1488 if (ret & NOTIFY_STOP_MASK)
1491 /* do the re-parent */
1492 ret = __clk_set_parent(clk, parent, p_index);
1494 /* propagate rate recalculation accordingly */
1496 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1498 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1501 clk_prepare_unlock();
1505 EXPORT_SYMBOL_GPL(clk_set_parent);
1508 * __clk_init - initialize the data structures in a struct clk
1509 * @dev: device initializing this clk, placeholder for now
1510 * @clk: clk being initialized
1512 * Initializes the lists in struct clk, queries the hardware for the
1513 * parent and rate and sets them both.
1515 int __clk_init(struct device *dev, struct clk *clk)
1519 struct hlist_node *tmp2;
1526 /* check to see if a clock with this name is already registered */
1527 if (__clk_lookup(clk->name)) {
1528 pr_debug("%s: clk %s already initialized\n",
1529 __func__, clk->name);
1534 /* check that clk_ops are sane. See Documentation/clk.txt */
1535 if (clk->ops->set_rate &&
1536 !(clk->ops->round_rate && clk->ops->recalc_rate)) {
1537 pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
1538 __func__, clk->name);
1543 if (clk->ops->set_parent && !clk->ops->get_parent) {
1544 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1545 __func__, clk->name);
1550 /* throw a WARN if any entries in parent_names are NULL */
1551 for (i = 0; i < clk->num_parents; i++)
1552 WARN(!clk->parent_names[i],
1553 "%s: invalid NULL in %s's .parent_names\n",
1554 __func__, clk->name);
1557 * Allocate an array of struct clk *'s to avoid unnecessary string
1558 * look-ups of clk's possible parents. This can fail for clocks passed
1559 * in to clk_init during early boot; thus any access to clk->parents[]
1560 * must always check for a NULL pointer and try to populate it if
1563 * If clk->parents is not NULL we skip this entire block. This allows
1564 * for clock drivers to statically initialize clk->parents.
1566 if (clk->num_parents > 1 && !clk->parents) {
1567 clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1570 * __clk_lookup returns NULL for parents that have not been
1571 * clk_init'd; thus any access to clk->parents[] must check
1572 * for a NULL pointer. We can always perform lazy lookups for
1573 * missing parents later on.
1576 for (i = 0; i < clk->num_parents; i++)
1578 __clk_lookup(clk->parent_names[i]);
1581 clk->parent = __clk_init_parent(clk);
1584 * Populate clk->parent if parent has already been __clk_init'd. If
1585 * parent has not yet been __clk_init'd then place clk in the orphan
1586 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1589 * Every time a new clk is clk_init'd then we walk the list of orphan
1590 * clocks and re-parent any that are children of the clock currently
1594 hlist_add_head(&clk->child_node,
1595 &clk->parent->children);
1596 else if (clk->flags & CLK_IS_ROOT)
1597 hlist_add_head(&clk->child_node, &clk_root_list);
1599 hlist_add_head(&clk->child_node, &clk_orphan_list);
1602 * Set clk's rate. The preferred method is to use .recalc_rate. For
1603 * simple clocks and lazy developers the default fallback is to use the
1604 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1605 * then rate is set to zero.
1607 if (clk->ops->recalc_rate)
1608 clk->rate = clk->ops->recalc_rate(clk->hw,
1609 __clk_get_rate(clk->parent));
1610 else if (clk->parent)
1611 clk->rate = clk->parent->rate;
1616 * walk the list of orphan clocks and reparent any that are children of
1619 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1620 if (orphan->ops->get_parent) {
1621 i = orphan->ops->get_parent(orphan->hw);
1622 if (!strcmp(clk->name, orphan->parent_names[i]))
1623 __clk_reparent(orphan, clk);
1627 for (i = 0; i < orphan->num_parents; i++)
1628 if (!strcmp(clk->name, orphan->parent_names[i])) {
1629 __clk_reparent(orphan, clk);
1635 * optional platform-specific magic
1637 * The .init callback is not used by any of the basic clock types, but
1638 * exists for weird hardware that must perform initialization magic.
1639 * Please consider other ways of solving initialization problems before
1640 * using this callback, as it's use is discouraged.
1643 clk->ops->init(clk->hw);
1645 clk_debug_register(clk);
1648 clk_prepare_unlock();
1654 * __clk_register - register a clock and return a cookie.
1656 * Same as clk_register, except that the .clk field inside hw shall point to a
1657 * preallocated (generally statically allocated) struct clk. None of the fields
1658 * of the struct clk need to be initialized.
1660 * The data pointed to by .init and .clk field shall NOT be marked as init
1663 * __clk_register is only exposed via clk-private.h and is intended for use with
1664 * very large numbers of clocks that need to be statically initialized. It is
1665 * a layering violation to include clk-private.h from any code which implements
1666 * a clock's .ops; as such any statically initialized clock data MUST be in a
1667 * separate C file from the logic that implements it's operations. Returns 0
1668 * on success, otherwise an error code.
1670 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1676 clk->name = hw->init->name;
1677 clk->ops = hw->init->ops;
1679 clk->flags = hw->init->flags;
1680 clk->parent_names = hw->init->parent_names;
1681 clk->num_parents = hw->init->num_parents;
1683 ret = __clk_init(dev, clk);
1685 return ERR_PTR(ret);
1689 EXPORT_SYMBOL_GPL(__clk_register);
1691 static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
1695 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1697 pr_err("%s: could not allocate clk->name\n", __func__);
1701 clk->ops = hw->init->ops;
1703 clk->flags = hw->init->flags;
1704 clk->num_parents = hw->init->num_parents;
1707 /* allocate local copy in case parent_names is __initdata */
1708 clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents),
1711 if (!clk->parent_names) {
1712 pr_err("%s: could not allocate clk->parent_names\n", __func__);
1714 goto fail_parent_names;
1718 /* copy each string name in case parent_names is __initdata */
1719 for (i = 0; i < clk->num_parents; i++) {
1720 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1722 if (!clk->parent_names[i]) {
1723 pr_err("%s: could not copy parent_names\n", __func__);
1725 goto fail_parent_names_copy;
1729 ret = __clk_init(dev, clk);
1733 fail_parent_names_copy:
1735 kfree(clk->parent_names[i]);
1736 kfree(clk->parent_names);
1744 * clk_register - allocate a new clock, register it and return an opaque cookie
1745 * @dev: device that is registering this clock
1746 * @hw: link to hardware-specific clock data
1748 * clk_register is the primary interface for populating the clock tree with new
1749 * clock nodes. It returns a pointer to the newly allocated struct clk which
1750 * cannot be dereferenced by driver code but may be used in conjuction with the
1751 * rest of the clock API. In the event of an error clk_register will return an
1752 * error code; drivers must test for an error code after calling clk_register.
1754 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1759 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1761 pr_err("%s: could not allocate clk\n", __func__);
1766 ret = _clk_register(dev, hw, clk);
1772 return ERR_PTR(ret);
1774 EXPORT_SYMBOL_GPL(clk_register);
1777 * clk_unregister - unregister a currently registered clock
1778 * @clk: clock to unregister
1780 * Currently unimplemented.
1782 void clk_unregister(struct clk *clk) {}
1783 EXPORT_SYMBOL_GPL(clk_unregister);
1785 static void devm_clk_release(struct device *dev, void *res)
1787 clk_unregister(res);
1791 * devm_clk_register - resource managed clk_register()
1792 * @dev: device that is registering this clock
1793 * @hw: link to hardware-specific clock data
1795 * Managed clk_register(). Clocks returned from this function are
1796 * automatically clk_unregister()ed on driver detach. See clk_register() for
1799 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
1804 clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
1806 return ERR_PTR(-ENOMEM);
1808 ret = _clk_register(dev, hw, clk);
1810 devres_add(dev, clk);
1818 EXPORT_SYMBOL_GPL(devm_clk_register);
1820 static int devm_clk_match(struct device *dev, void *res, void *data)
1822 struct clk *c = res;
1829 * devm_clk_unregister - resource managed clk_unregister()
1830 * @clk: clock to unregister
1832 * Deallocate a clock allocated with devm_clk_register(). Normally
1833 * this function will not need to be called and the resource management
1834 * code will ensure that the resource is freed.
1836 void devm_clk_unregister(struct device *dev, struct clk *clk)
1838 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
1840 EXPORT_SYMBOL_GPL(devm_clk_unregister);
1842 /*** clk rate change notifiers ***/
1845 * clk_notifier_register - add a clk rate change notifier
1846 * @clk: struct clk * to watch
1847 * @nb: struct notifier_block * with callback info
1849 * Request notification when clk's rate changes. This uses an SRCU
1850 * notifier because we want it to block and notifier unregistrations are
1851 * uncommon. The callbacks associated with the notifier must not
1852 * re-enter into the clk framework by calling any top-level clk APIs;
1853 * this will cause a nested prepare_lock mutex.
1855 * Pre-change notifier callbacks will be passed the current, pre-change
1856 * rate of the clk via struct clk_notifier_data.old_rate. The new,
1857 * post-change rate of the clk is passed via struct
1858 * clk_notifier_data.new_rate.
1860 * Post-change notifiers will pass the now-current, post-change rate of
1861 * the clk in both struct clk_notifier_data.old_rate and struct
1862 * clk_notifier_data.new_rate.
1864 * Abort-change notifiers are effectively the opposite of pre-change
1865 * notifiers: the original pre-change clk rate is passed in via struct
1866 * clk_notifier_data.new_rate and the failed post-change rate is passed
1867 * in via struct clk_notifier_data.old_rate.
1869 * clk_notifier_register() must be called from non-atomic context.
1870 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1871 * allocation failure; otherwise, passes along the return value of
1872 * srcu_notifier_chain_register().
1874 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
1876 struct clk_notifier *cn;
1884 /* search the list of notifiers for this clk */
1885 list_for_each_entry(cn, &clk_notifier_list, node)
1889 /* if clk wasn't in the notifier list, allocate new clk_notifier */
1890 if (cn->clk != clk) {
1891 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
1896 srcu_init_notifier_head(&cn->notifier_head);
1898 list_add(&cn->node, &clk_notifier_list);
1901 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
1903 clk->notifier_count++;
1906 clk_prepare_unlock();
1910 EXPORT_SYMBOL_GPL(clk_notifier_register);
1913 * clk_notifier_unregister - remove a clk rate change notifier
1914 * @clk: struct clk *
1915 * @nb: struct notifier_block * with callback info
1917 * Request no further notification for changes to 'clk' and frees memory
1918 * allocated in clk_notifier_register.
1920 * Returns -EINVAL if called with null arguments; otherwise, passes
1921 * along the return value of srcu_notifier_chain_unregister().
1923 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
1925 struct clk_notifier *cn = NULL;
1933 list_for_each_entry(cn, &clk_notifier_list, node)
1937 if (cn->clk == clk) {
1938 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
1940 clk->notifier_count--;
1942 /* XXX the notifier code should handle this better */
1943 if (!cn->notifier_head.head) {
1944 srcu_cleanup_notifier_head(&cn->notifier_head);
1952 clk_prepare_unlock();
1956 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
1960 * struct of_clk_provider - Clock provider registration structure
1961 * @link: Entry in global list of clock providers
1962 * @node: Pointer to device tree node of clock provider
1963 * @get: Get clock callback. Returns NULL or a struct clk for the
1964 * given clock specifier
1965 * @data: context pointer to be passed into @get callback
1967 struct of_clk_provider {
1968 struct list_head link;
1970 struct device_node *node;
1971 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
1975 extern struct of_device_id __clk_of_table[];
1977 static const struct of_device_id __clk_of_table_sentinel
1978 __used __section(__clk_of_table_end);
1980 static LIST_HEAD(of_clk_providers);
1981 static DEFINE_MUTEX(of_clk_lock);
1983 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
1988 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
1990 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
1992 struct clk_onecell_data *clk_data = data;
1993 unsigned int idx = clkspec->args[0];
1995 if (idx >= clk_data->clk_num) {
1996 pr_err("%s: invalid clock index %d\n", __func__, idx);
1997 return ERR_PTR(-EINVAL);
2000 return clk_data->clks[idx];
2002 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2005 * of_clk_add_provider() - Register a clock provider for a node
2006 * @np: Device node pointer associated with clock provider
2007 * @clk_src_get: callback for decoding clock
2008 * @data: context pointer for @clk_src_get callback.
2010 int of_clk_add_provider(struct device_node *np,
2011 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2015 struct of_clk_provider *cp;
2017 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2021 cp->node = of_node_get(np);
2023 cp->get = clk_src_get;
2025 mutex_lock(&of_clk_lock);
2026 list_add(&cp->link, &of_clk_providers);
2027 mutex_unlock(&of_clk_lock);
2028 pr_debug("Added clock from %s\n", np->full_name);
2032 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2035 * of_clk_del_provider() - Remove a previously registered clock provider
2036 * @np: Device node pointer associated with clock provider
2038 void of_clk_del_provider(struct device_node *np)
2040 struct of_clk_provider *cp;
2042 mutex_lock(&of_clk_lock);
2043 list_for_each_entry(cp, &of_clk_providers, link) {
2044 if (cp->node == np) {
2045 list_del(&cp->link);
2046 of_node_put(cp->node);
2051 mutex_unlock(&of_clk_lock);
2053 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2055 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2057 struct of_clk_provider *provider;
2058 struct clk *clk = ERR_PTR(-ENOENT);
2060 /* Check if we have such a provider in our array */
2061 mutex_lock(&of_clk_lock);
2062 list_for_each_entry(provider, &of_clk_providers, link) {
2063 if (provider->node == clkspec->np)
2064 clk = provider->get(clkspec, provider->data);
2068 mutex_unlock(&of_clk_lock);
2073 const char *of_clk_get_parent_name(struct device_node *np, int index)
2075 struct of_phandle_args clkspec;
2076 const char *clk_name;
2082 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2087 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2088 clkspec.args_count ? clkspec.args[0] : 0,
2090 clk_name = clkspec.np->name;
2092 of_node_put(clkspec.np);
2095 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2098 * of_clk_init() - Scan and init clock providers from the DT
2099 * @matches: array of compatible values and init functions for providers.
2101 * This function scans the device tree for matching clock providers and
2102 * calls their initialization functions
2104 void __init of_clk_init(const struct of_device_id *matches)
2106 struct device_node *np;
2109 matches = __clk_of_table;
2111 for_each_matching_node(np, matches) {
2112 const struct of_device_id *match = of_match_node(matches, np);
2113 of_clk_init_cb_t clk_init_cb = match->data;