2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
12 #include <linux/clk-private.h>
13 #include <linux/clk/clk-conf.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/spinlock.h>
17 #include <linux/err.h>
18 #include <linux/list.h>
19 #include <linux/slab.h>
21 #include <linux/device.h>
22 #include <linux/init.h>
23 #include <linux/sched.h>
27 static DEFINE_SPINLOCK(enable_lock);
28 static DEFINE_MUTEX(prepare_lock);
30 static struct task_struct *prepare_owner;
31 static struct task_struct *enable_owner;
33 static int prepare_refcnt;
34 static int enable_refcnt;
36 static HLIST_HEAD(clk_root_list);
37 static HLIST_HEAD(clk_orphan_list);
38 static LIST_HEAD(clk_notifier_list);
41 static void clk_prepare_lock(void)
43 if (!mutex_trylock(&prepare_lock)) {
44 if (prepare_owner == current) {
48 mutex_lock(&prepare_lock);
50 WARN_ON_ONCE(prepare_owner != NULL);
51 WARN_ON_ONCE(prepare_refcnt != 0);
52 prepare_owner = current;
56 static void clk_prepare_unlock(void)
58 WARN_ON_ONCE(prepare_owner != current);
59 WARN_ON_ONCE(prepare_refcnt == 0);
64 mutex_unlock(&prepare_lock);
67 static unsigned long clk_enable_lock(void)
71 if (!spin_trylock_irqsave(&enable_lock, flags)) {
72 if (enable_owner == current) {
76 spin_lock_irqsave(&enable_lock, flags);
78 WARN_ON_ONCE(enable_owner != NULL);
79 WARN_ON_ONCE(enable_refcnt != 0);
80 enable_owner = current;
85 static void clk_enable_unlock(unsigned long flags)
87 WARN_ON_ONCE(enable_owner != current);
88 WARN_ON_ONCE(enable_refcnt == 0);
93 spin_unlock_irqrestore(&enable_lock, flags);
96 /*** debugfs support ***/
98 #ifdef CONFIG_DEBUG_FS
99 #include <linux/debugfs.h>
101 static struct dentry *rootdir;
102 static int inited = 0;
103 static DEFINE_MUTEX(clk_debug_lock);
104 static HLIST_HEAD(clk_debug_list);
106 static struct hlist_head *all_lists[] = {
112 static struct hlist_head *orphan_list[] = {
117 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
122 seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
124 30 - level * 3, c->name,
125 c->enable_count, c->prepare_count, clk_get_rate(c),
126 clk_get_accuracy(c), clk_get_phase(c));
129 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
137 clk_summary_show_one(s, c, level);
139 hlist_for_each_entry(child, &c->children, child_node)
140 clk_summary_show_subtree(s, child, level + 1);
143 static int clk_summary_show(struct seq_file *s, void *data)
146 struct hlist_head **lists = (struct hlist_head **)s->private;
148 seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy phase\n");
149 seq_puts(s, "----------------------------------------------------------------------------------------\n");
153 for (; *lists; lists++)
154 hlist_for_each_entry(c, *lists, child_node)
155 clk_summary_show_subtree(s, c, 0);
157 clk_prepare_unlock();
163 static int clk_summary_open(struct inode *inode, struct file *file)
165 return single_open(file, clk_summary_show, inode->i_private);
168 static const struct file_operations clk_summary_fops = {
169 .open = clk_summary_open,
172 .release = single_release,
175 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
180 seq_printf(s, "\"%s\": { ", c->name);
181 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
182 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
183 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
184 seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
185 seq_printf(s, "\"phase\": %d", clk_get_phase(c));
188 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
195 clk_dump_one(s, c, level);
197 hlist_for_each_entry(child, &c->children, child_node) {
199 clk_dump_subtree(s, child, level + 1);
205 static int clk_dump(struct seq_file *s, void *data)
208 bool first_node = true;
209 struct hlist_head **lists = (struct hlist_head **)s->private;
215 for (; *lists; lists++) {
216 hlist_for_each_entry(c, *lists, child_node) {
220 clk_dump_subtree(s, c, 0);
224 clk_prepare_unlock();
231 static int clk_dump_open(struct inode *inode, struct file *file)
233 return single_open(file, clk_dump, inode->i_private);
236 static const struct file_operations clk_dump_fops = {
237 .open = clk_dump_open,
240 .release = single_release,
243 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
248 if (!clk || !pdentry) {
253 d = debugfs_create_dir(clk->name, pdentry);
259 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
264 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
265 (u32 *)&clk->accuracy);
269 d = debugfs_create_u32("clk_phase", S_IRUGO, clk->dentry,
274 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
279 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
280 (u32 *)&clk->prepare_count);
284 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
285 (u32 *)&clk->enable_count);
289 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
290 (u32 *)&clk->notifier_count);
294 if (clk->ops->debug_init) {
295 ret = clk->ops->debug_init(clk->hw, clk->dentry);
304 debugfs_remove_recursive(clk->dentry);
311 * clk_debug_register - add a clk node to the debugfs clk tree
312 * @clk: the clk being added to the debugfs clk tree
314 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
315 * initialized. Otherwise it bails out early since the debugfs clk tree
316 * will be created lazily by clk_debug_init as part of a late_initcall.
318 static int clk_debug_register(struct clk *clk)
322 mutex_lock(&clk_debug_lock);
323 hlist_add_head(&clk->debug_node, &clk_debug_list);
328 ret = clk_debug_create_one(clk, rootdir);
330 mutex_unlock(&clk_debug_lock);
336 * clk_debug_unregister - remove a clk node from the debugfs clk tree
337 * @clk: the clk being removed from the debugfs clk tree
339 * Dynamically removes a clk and all it's children clk nodes from the
340 * debugfs clk tree if clk->dentry points to debugfs created by
341 * clk_debug_register in __clk_init.
343 static void clk_debug_unregister(struct clk *clk)
345 mutex_lock(&clk_debug_lock);
349 hlist_del_init(&clk->debug_node);
350 debugfs_remove_recursive(clk->dentry);
353 mutex_unlock(&clk_debug_lock);
356 struct dentry *clk_debugfs_add_file(struct clk_hw *hw, char *name, umode_t mode,
357 void *data, const struct file_operations *fops)
359 struct dentry *d = NULL;
362 d = debugfs_create_file(name, mode, hw->clk->dentry, data, fops);
366 EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
369 * clk_debug_init - lazily create the debugfs clk tree visualization
371 * clks are often initialized very early during boot before memory can
372 * be dynamically allocated and well before debugfs is setup.
373 * clk_debug_init walks the clk tree hierarchy while holding
374 * prepare_lock and creates the topology as part of a late_initcall,
375 * thus insuring that clks initialized very early will still be
376 * represented in the debugfs clk tree. This function should only be
377 * called once at boot-time, and all other clks added dynamically will
378 * be done so with clk_debug_register.
380 static int __init clk_debug_init(void)
385 rootdir = debugfs_create_dir("clk", NULL);
390 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists,
395 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists,
400 d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir,
401 &orphan_list, &clk_summary_fops);
405 d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir,
406 &orphan_list, &clk_dump_fops);
410 mutex_lock(&clk_debug_lock);
411 hlist_for_each_entry(clk, &clk_debug_list, debug_node)
412 clk_debug_create_one(clk, rootdir);
415 mutex_unlock(&clk_debug_lock);
419 late_initcall(clk_debug_init);
421 static inline int clk_debug_register(struct clk *clk) { return 0; }
422 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
425 static inline void clk_debug_unregister(struct clk *clk)
430 /* caller must hold prepare_lock */
431 static void clk_unprepare_unused_subtree(struct clk *clk)
438 hlist_for_each_entry(child, &clk->children, child_node)
439 clk_unprepare_unused_subtree(child);
441 if (clk->prepare_count)
444 if (clk->flags & CLK_IGNORE_UNUSED)
447 if (__clk_is_prepared(clk)) {
448 if (clk->ops->unprepare_unused)
449 clk->ops->unprepare_unused(clk->hw);
450 else if (clk->ops->unprepare)
451 clk->ops->unprepare(clk->hw);
455 /* caller must hold prepare_lock */
456 static void clk_disable_unused_subtree(struct clk *clk)
464 hlist_for_each_entry(child, &clk->children, child_node)
465 clk_disable_unused_subtree(child);
467 flags = clk_enable_lock();
469 if (clk->enable_count)
472 if (clk->flags & CLK_IGNORE_UNUSED)
476 * some gate clocks have special needs during the disable-unused
477 * sequence. call .disable_unused if available, otherwise fall
480 if (__clk_is_enabled(clk)) {
481 if (clk->ops->disable_unused)
482 clk->ops->disable_unused(clk->hw);
483 else if (clk->ops->disable)
484 clk->ops->disable(clk->hw);
488 clk_enable_unlock(flags);
494 static bool clk_ignore_unused;
495 static int __init clk_ignore_unused_setup(char *__unused)
497 clk_ignore_unused = true;
500 __setup("clk_ignore_unused", clk_ignore_unused_setup);
502 static int clk_disable_unused(void)
506 if (clk_ignore_unused) {
507 pr_warn("clk: Not disabling unused clocks\n");
513 hlist_for_each_entry(clk, &clk_root_list, child_node)
514 clk_disable_unused_subtree(clk);
516 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
517 clk_disable_unused_subtree(clk);
519 hlist_for_each_entry(clk, &clk_root_list, child_node)
520 clk_unprepare_unused_subtree(clk);
522 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
523 clk_unprepare_unused_subtree(clk);
525 clk_prepare_unlock();
529 late_initcall_sync(clk_disable_unused);
531 /*** helper functions ***/
533 const char *__clk_get_name(struct clk *clk)
535 return !clk ? NULL : clk->name;
537 EXPORT_SYMBOL_GPL(__clk_get_name);
539 struct clk_hw *__clk_get_hw(struct clk *clk)
541 return !clk ? NULL : clk->hw;
543 EXPORT_SYMBOL_GPL(__clk_get_hw);
545 u8 __clk_get_num_parents(struct clk *clk)
547 return !clk ? 0 : clk->num_parents;
549 EXPORT_SYMBOL_GPL(__clk_get_num_parents);
551 struct clk *__clk_get_parent(struct clk *clk)
553 return !clk ? NULL : clk->parent;
555 EXPORT_SYMBOL_GPL(__clk_get_parent);
557 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
559 if (!clk || index >= clk->num_parents)
561 else if (!clk->parents)
562 return __clk_lookup(clk->parent_names[index]);
563 else if (!clk->parents[index])
564 return clk->parents[index] =
565 __clk_lookup(clk->parent_names[index]);
567 return clk->parents[index];
569 EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
571 unsigned int __clk_get_enable_count(struct clk *clk)
573 return !clk ? 0 : clk->enable_count;
576 unsigned long __clk_get_rate(struct clk *clk)
587 if (clk->flags & CLK_IS_ROOT)
596 EXPORT_SYMBOL_GPL(__clk_get_rate);
598 static unsigned long __clk_get_accuracy(struct clk *clk)
603 return clk->accuracy;
606 unsigned long __clk_get_flags(struct clk *clk)
608 return !clk ? 0 : clk->flags;
610 EXPORT_SYMBOL_GPL(__clk_get_flags);
612 bool __clk_is_prepared(struct clk *clk)
620 * .is_prepared is optional for clocks that can prepare
621 * fall back to software usage counter if it is missing
623 if (!clk->ops->is_prepared) {
624 ret = clk->prepare_count ? 1 : 0;
628 ret = clk->ops->is_prepared(clk->hw);
633 bool __clk_is_enabled(struct clk *clk)
641 * .is_enabled is only mandatory for clocks that gate
642 * fall back to software usage counter if .is_enabled is missing
644 if (!clk->ops->is_enabled) {
645 ret = clk->enable_count ? 1 : 0;
649 ret = clk->ops->is_enabled(clk->hw);
653 EXPORT_SYMBOL_GPL(__clk_is_enabled);
655 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
660 if (!strcmp(clk->name, name))
663 hlist_for_each_entry(child, &clk->children, child_node) {
664 ret = __clk_lookup_subtree(name, child);
672 struct clk *__clk_lookup(const char *name)
674 struct clk *root_clk;
680 /* search the 'proper' clk tree first */
681 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
682 ret = __clk_lookup_subtree(name, root_clk);
687 /* if not found, then search the orphan tree */
688 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
689 ret = __clk_lookup_subtree(name, root_clk);
698 * Helper for finding best parent to provide a given frequency. This can be used
699 * directly as a determine_rate callback (e.g. for a mux), or from a more
700 * complex clock that may combine a mux with other operations.
702 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
703 unsigned long *best_parent_rate,
704 struct clk_hw **best_parent_p)
706 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
708 unsigned long parent_rate, best = 0;
710 /* if NO_REPARENT flag set, pass through to current parent */
711 if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
712 parent = clk->parent;
713 if (clk->flags & CLK_SET_RATE_PARENT)
714 best = __clk_round_rate(parent, rate);
716 best = __clk_get_rate(parent);
718 best = __clk_get_rate(clk);
722 /* find the parent that can provide the fastest rate <= rate */
723 num_parents = clk->num_parents;
724 for (i = 0; i < num_parents; i++) {
725 parent = clk_get_parent_by_index(clk, i);
728 if (clk->flags & CLK_SET_RATE_PARENT)
729 parent_rate = __clk_round_rate(parent, rate);
731 parent_rate = __clk_get_rate(parent);
732 if (parent_rate <= rate && parent_rate > best) {
733 best_parent = parent;
740 *best_parent_p = best_parent->hw;
741 *best_parent_rate = best;
745 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
749 void __clk_unprepare(struct clk *clk)
754 if (WARN_ON(clk->prepare_count == 0))
757 if (--clk->prepare_count > 0)
760 WARN_ON(clk->enable_count > 0);
762 if (clk->ops->unprepare)
763 clk->ops->unprepare(clk->hw);
765 __clk_unprepare(clk->parent);
769 * clk_unprepare - undo preparation of a clock source
770 * @clk: the clk being unprepared
772 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
773 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
774 * if the operation may sleep. One example is a clk which is accessed over
775 * I2c. In the complex case a clk gate operation may require a fast and a slow
776 * part. It is this reason that clk_unprepare and clk_disable are not mutually
777 * exclusive. In fact clk_disable must be called before clk_unprepare.
779 void clk_unprepare(struct clk *clk)
781 if (IS_ERR_OR_NULL(clk))
785 __clk_unprepare(clk);
786 clk_prepare_unlock();
788 EXPORT_SYMBOL_GPL(clk_unprepare);
790 int __clk_prepare(struct clk *clk)
797 if (clk->prepare_count == 0) {
798 ret = __clk_prepare(clk->parent);
802 if (clk->ops->prepare) {
803 ret = clk->ops->prepare(clk->hw);
805 __clk_unprepare(clk->parent);
811 clk->prepare_count++;
817 * clk_prepare - prepare a clock source
818 * @clk: the clk being prepared
820 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
821 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
822 * operation may sleep. One example is a clk which is accessed over I2c. In
823 * the complex case a clk ungate operation may require a fast and a slow part.
824 * It is this reason that clk_prepare and clk_enable are not mutually
825 * exclusive. In fact clk_prepare must be called before clk_enable.
826 * Returns 0 on success, -EERROR otherwise.
828 int clk_prepare(struct clk *clk)
833 ret = __clk_prepare(clk);
834 clk_prepare_unlock();
838 EXPORT_SYMBOL_GPL(clk_prepare);
840 static void __clk_disable(struct clk *clk)
845 if (WARN_ON(clk->enable_count == 0))
848 if (--clk->enable_count > 0)
851 if (clk->ops->disable)
852 clk->ops->disable(clk->hw);
854 __clk_disable(clk->parent);
858 * clk_disable - gate a clock
859 * @clk: the clk being gated
861 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
862 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
863 * clk if the operation is fast and will never sleep. One example is a
864 * SoC-internal clk which is controlled via simple register writes. In the
865 * complex case a clk gate operation may require a fast and a slow part. It is
866 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
867 * In fact clk_disable must be called before clk_unprepare.
869 void clk_disable(struct clk *clk)
873 if (IS_ERR_OR_NULL(clk))
876 flags = clk_enable_lock();
878 clk_enable_unlock(flags);
880 EXPORT_SYMBOL_GPL(clk_disable);
882 static int __clk_enable(struct clk *clk)
889 if (WARN_ON(clk->prepare_count == 0))
892 if (clk->enable_count == 0) {
893 ret = __clk_enable(clk->parent);
898 if (clk->ops->enable) {
899 ret = clk->ops->enable(clk->hw);
901 __clk_disable(clk->parent);
912 * clk_enable - ungate a clock
913 * @clk: the clk being ungated
915 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
916 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
917 * if the operation will never sleep. One example is a SoC-internal clk which
918 * is controlled via simple register writes. In the complex case a clk ungate
919 * operation may require a fast and a slow part. It is this reason that
920 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
921 * must be called before clk_enable. Returns 0 on success, -EERROR
924 int clk_enable(struct clk *clk)
929 flags = clk_enable_lock();
930 ret = __clk_enable(clk);
931 clk_enable_unlock(flags);
935 EXPORT_SYMBOL_GPL(clk_enable);
938 * __clk_round_rate - round the given rate for a clk
939 * @clk: round the rate of this clock
940 * @rate: the rate which is to be rounded
942 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
944 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
946 unsigned long parent_rate = 0;
948 struct clk_hw *parent_hw;
953 parent = clk->parent;
955 parent_rate = parent->rate;
957 if (clk->ops->determine_rate) {
958 parent_hw = parent ? parent->hw : NULL;
959 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
961 } else if (clk->ops->round_rate)
962 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
963 else if (clk->flags & CLK_SET_RATE_PARENT)
964 return __clk_round_rate(clk->parent, rate);
968 EXPORT_SYMBOL_GPL(__clk_round_rate);
971 * clk_round_rate - round the given rate for a clk
972 * @clk: the clk for which we are rounding a rate
973 * @rate: the rate which is to be rounded
975 * Takes in a rate as input and rounds it to a rate that the clk can actually
976 * use which is then returned. If clk doesn't support round_rate operation
977 * then the parent rate is returned.
979 long clk_round_rate(struct clk *clk, unsigned long rate)
984 ret = __clk_round_rate(clk, rate);
985 clk_prepare_unlock();
989 EXPORT_SYMBOL_GPL(clk_round_rate);
992 * __clk_notify - call clk notifier chain
993 * @clk: struct clk * that is changing rate
994 * @msg: clk notifier type (see include/linux/clk.h)
995 * @old_rate: old clk rate
996 * @new_rate: new clk rate
998 * Triggers a notifier call chain on the clk rate-change notification
999 * for 'clk'. Passes a pointer to the struct clk and the previous
1000 * and current rates to the notifier callback. Intended to be called by
1001 * internal clock code only. Returns NOTIFY_DONE from the last driver
1002 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1003 * a driver returns that.
1005 static int __clk_notify(struct clk *clk, unsigned long msg,
1006 unsigned long old_rate, unsigned long new_rate)
1008 struct clk_notifier *cn;
1009 struct clk_notifier_data cnd;
1010 int ret = NOTIFY_DONE;
1013 cnd.old_rate = old_rate;
1014 cnd.new_rate = new_rate;
1016 list_for_each_entry(cn, &clk_notifier_list, node) {
1017 if (cn->clk == clk) {
1018 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1028 * __clk_recalc_accuracies
1029 * @clk: first clk in the subtree
1031 * Walks the subtree of clks starting with clk and recalculates accuracies as
1032 * it goes. Note that if a clk does not implement the .recalc_accuracy
1033 * callback then it is assumed that the clock will take on the accuracy of it's
1036 * Caller must hold prepare_lock.
1038 static void __clk_recalc_accuracies(struct clk *clk)
1040 unsigned long parent_accuracy = 0;
1044 parent_accuracy = clk->parent->accuracy;
1046 if (clk->ops->recalc_accuracy)
1047 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1050 clk->accuracy = parent_accuracy;
1052 hlist_for_each_entry(child, &clk->children, child_node)
1053 __clk_recalc_accuracies(child);
1057 * clk_get_accuracy - return the accuracy of clk
1058 * @clk: the clk whose accuracy is being returned
1060 * Simply returns the cached accuracy of the clk, unless
1061 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1063 * If clk is NULL then returns 0.
1065 long clk_get_accuracy(struct clk *clk)
1067 unsigned long accuracy;
1070 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1071 __clk_recalc_accuracies(clk);
1073 accuracy = __clk_get_accuracy(clk);
1074 clk_prepare_unlock();
1078 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1080 static unsigned long clk_recalc(struct clk *clk, unsigned long parent_rate)
1082 if (clk->ops->recalc_rate)
1083 return clk->ops->recalc_rate(clk->hw, parent_rate);
1088 * __clk_recalc_rates
1089 * @clk: first clk in the subtree
1090 * @msg: notification type (see include/linux/clk.h)
1092 * Walks the subtree of clks starting with clk and recalculates rates as it
1093 * goes. Note that if a clk does not implement the .recalc_rate callback then
1094 * it is assumed that the clock will take on the rate of its parent.
1096 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1099 * Caller must hold prepare_lock.
1101 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
1103 unsigned long old_rate;
1104 unsigned long parent_rate = 0;
1107 old_rate = clk->rate;
1110 parent_rate = clk->parent->rate;
1112 clk->rate = clk_recalc(clk, parent_rate);
1115 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1116 * & ABORT_RATE_CHANGE notifiers
1118 if (clk->notifier_count && msg)
1119 __clk_notify(clk, msg, old_rate, clk->rate);
1121 hlist_for_each_entry(child, &clk->children, child_node)
1122 __clk_recalc_rates(child, msg);
1126 * clk_get_rate - return the rate of clk
1127 * @clk: the clk whose rate is being returned
1129 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1130 * is set, which means a recalc_rate will be issued.
1131 * If clk is NULL then returns 0.
1133 unsigned long clk_get_rate(struct clk *clk)
1139 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1140 __clk_recalc_rates(clk, 0);
1142 rate = __clk_get_rate(clk);
1143 clk_prepare_unlock();
1147 EXPORT_SYMBOL_GPL(clk_get_rate);
1149 static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1153 if (!clk->parents) {
1154 clk->parents = kcalloc(clk->num_parents,
1155 sizeof(struct clk *), GFP_KERNEL);
1161 * find index of new parent clock using cached parent ptrs,
1162 * or if not yet cached, use string name comparison and cache
1163 * them now to avoid future calls to __clk_lookup.
1165 for (i = 0; i < clk->num_parents; i++) {
1166 if (clk->parents[i] == parent)
1169 if (clk->parents[i])
1172 if (!strcmp(clk->parent_names[i], parent->name)) {
1173 clk->parents[i] = __clk_lookup(parent->name);
1181 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1183 hlist_del(&clk->child_node);
1186 /* avoid duplicate POST_RATE_CHANGE notifications */
1187 if (new_parent->new_child == clk)
1188 new_parent->new_child = NULL;
1190 hlist_add_head(&clk->child_node, &new_parent->children);
1192 hlist_add_head(&clk->child_node, &clk_orphan_list);
1195 clk->parent = new_parent;
1198 static struct clk *__clk_set_parent_before(struct clk *clk, struct clk *parent)
1200 unsigned long flags;
1201 struct clk *old_parent = clk->parent;
1204 * Migrate prepare state between parents and prevent race with
1207 * If the clock is not prepared, then a race with
1208 * clk_enable/disable() is impossible since we already have the
1209 * prepare lock (future calls to clk_enable() need to be preceded by
1212 * If the clock is prepared, migrate the prepared state to the new
1213 * parent and also protect against a race with clk_enable() by
1214 * forcing the clock and the new parent on. This ensures that all
1215 * future calls to clk_enable() are practically NOPs with respect to
1216 * hardware and software states.
1218 * See also: Comment for clk_set_parent() below.
1220 if (clk->prepare_count) {
1221 __clk_prepare(parent);
1226 /* update the clk tree topology */
1227 flags = clk_enable_lock();
1228 clk_reparent(clk, parent);
1229 clk_enable_unlock(flags);
1234 static void __clk_set_parent_after(struct clk *clk, struct clk *parent,
1235 struct clk *old_parent)
1238 * Finish the migration of prepare state and undo the changes done
1239 * for preventing a race with clk_enable().
1241 if (clk->prepare_count) {
1243 clk_disable(old_parent);
1244 __clk_unprepare(old_parent);
1248 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1250 unsigned long flags;
1252 struct clk *old_parent;
1254 old_parent = __clk_set_parent_before(clk, parent);
1256 /* change clock input source */
1257 if (parent && clk->ops->set_parent)
1258 ret = clk->ops->set_parent(clk->hw, p_index);
1261 flags = clk_enable_lock();
1262 clk_reparent(clk, old_parent);
1263 clk_enable_unlock(flags);
1265 if (clk->prepare_count) {
1267 clk_disable(parent);
1268 __clk_unprepare(parent);
1273 __clk_set_parent_after(clk, parent, old_parent);
1279 * __clk_speculate_rates
1280 * @clk: first clk in the subtree
1281 * @parent_rate: the "future" rate of clk's parent
1283 * Walks the subtree of clks starting with clk, speculating rates as it
1284 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1286 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1287 * pre-rate change notifications and returns early if no clks in the
1288 * subtree have subscribed to the notifications. Note that if a clk does not
1289 * implement the .recalc_rate callback then it is assumed that the clock will
1290 * take on the rate of its parent.
1292 * Caller must hold prepare_lock.
1294 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1297 unsigned long new_rate;
1298 int ret = NOTIFY_DONE;
1300 new_rate = clk_recalc(clk, parent_rate);
1302 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1303 if (clk->notifier_count)
1304 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1306 if (ret & NOTIFY_STOP_MASK) {
1307 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1308 __func__, clk->name, ret);
1312 hlist_for_each_entry(child, &clk->children, child_node) {
1313 ret = __clk_speculate_rates(child, new_rate);
1314 if (ret & NOTIFY_STOP_MASK)
1322 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1323 struct clk *new_parent, u8 p_index)
1327 clk->new_rate = new_rate;
1328 clk->new_parent = new_parent;
1329 clk->new_parent_index = p_index;
1330 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1331 clk->new_child = NULL;
1332 if (new_parent && new_parent != clk->parent)
1333 new_parent->new_child = clk;
1335 hlist_for_each_entry(child, &clk->children, child_node) {
1336 child->new_rate = clk_recalc(child, new_rate);
1337 clk_calc_subtree(child, child->new_rate, NULL, 0);
1342 * calculate the new rates returning the topmost clock that has to be
1345 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1347 struct clk *top = clk;
1348 struct clk *old_parent, *parent;
1349 struct clk_hw *parent_hw;
1350 unsigned long best_parent_rate = 0;
1351 unsigned long new_rate;
1355 if (IS_ERR_OR_NULL(clk))
1358 /* save parent rate, if it exists */
1359 parent = old_parent = clk->parent;
1361 best_parent_rate = parent->rate;
1363 /* find the closest rate and parent clk/rate */
1364 if (clk->ops->determine_rate) {
1365 parent_hw = parent ? parent->hw : NULL;
1366 new_rate = clk->ops->determine_rate(clk->hw, rate,
1369 parent = parent_hw ? parent_hw->clk : NULL;
1370 } else if (clk->ops->round_rate) {
1371 new_rate = clk->ops->round_rate(clk->hw, rate,
1373 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1374 /* pass-through clock without adjustable parent */
1375 clk->new_rate = clk->rate;
1378 /* pass-through clock with adjustable parent */
1379 top = clk_calc_new_rates(parent, rate);
1380 new_rate = parent->new_rate;
1384 /* some clocks must be gated to change parent */
1385 if (parent != old_parent &&
1386 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1387 pr_debug("%s: %s not gated but wants to reparent\n",
1388 __func__, clk->name);
1392 /* try finding the new parent index */
1393 if (parent && clk->num_parents > 1) {
1394 p_index = clk_fetch_parent_index(clk, parent);
1396 pr_debug("%s: clk %s can not be parent of clk %s\n",
1397 __func__, parent->name, clk->name);
1402 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1403 best_parent_rate != parent->rate)
1404 top = clk_calc_new_rates(parent, best_parent_rate);
1407 clk_calc_subtree(clk, new_rate, parent, p_index);
1413 * Notify about rate changes in a subtree. Always walk down the whole tree
1414 * so that in case of an error we can walk down the whole tree again and
1417 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1419 struct clk *child, *tmp_clk, *fail_clk = NULL;
1420 int ret = NOTIFY_DONE;
1422 if (clk->rate == clk->new_rate)
1425 if (clk->notifier_count) {
1426 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1427 if (ret & NOTIFY_STOP_MASK)
1431 hlist_for_each_entry(child, &clk->children, child_node) {
1432 /* Skip children who will be reparented to another clock */
1433 if (child->new_parent && child->new_parent != clk)
1435 tmp_clk = clk_propagate_rate_change(child, event);
1440 /* handle the new child who might not be in clk->children yet */
1441 if (clk->new_child) {
1442 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1451 * walk down a subtree and set the new rates notifying the rate
1454 static void clk_change_rate(struct clk *clk)
1457 struct hlist_node *tmp;
1458 unsigned long old_rate;
1459 unsigned long best_parent_rate = 0;
1460 bool skip_set_rate = false;
1461 struct clk *old_parent;
1463 old_rate = clk->rate;
1465 if (clk->new_parent)
1466 best_parent_rate = clk->new_parent->rate;
1467 else if (clk->parent)
1468 best_parent_rate = clk->parent->rate;
1470 if (clk->new_parent && clk->new_parent != clk->parent) {
1471 old_parent = __clk_set_parent_before(clk, clk->new_parent);
1473 if (clk->ops->set_rate_and_parent) {
1474 skip_set_rate = true;
1475 clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
1477 clk->new_parent_index);
1478 } else if (clk->ops->set_parent) {
1479 clk->ops->set_parent(clk->hw, clk->new_parent_index);
1482 __clk_set_parent_after(clk, clk->new_parent, old_parent);
1485 if (!skip_set_rate && clk->ops->set_rate)
1486 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1488 clk->rate = clk_recalc(clk, best_parent_rate);
1490 if (clk->notifier_count && old_rate != clk->rate)
1491 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1494 * Use safe iteration, as change_rate can actually swap parents
1495 * for certain clock types.
1497 hlist_for_each_entry_safe(child, tmp, &clk->children, child_node) {
1498 /* Skip children who will be reparented to another clock */
1499 if (child->new_parent && child->new_parent != clk)
1501 clk_change_rate(child);
1504 /* handle the new child who might not be in clk->children yet */
1506 clk_change_rate(clk->new_child);
1510 * clk_set_rate - specify a new rate for clk
1511 * @clk: the clk whose rate is being changed
1512 * @rate: the new rate for clk
1514 * In the simplest case clk_set_rate will only adjust the rate of clk.
1516 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1517 * propagate up to clk's parent; whether or not this happens depends on the
1518 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1519 * after calling .round_rate then upstream parent propagation is ignored. If
1520 * *parent_rate comes back with a new rate for clk's parent then we propagate
1521 * up to clk's parent and set its rate. Upward propagation will continue
1522 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1523 * .round_rate stops requesting changes to clk's parent_rate.
1525 * Rate changes are accomplished via tree traversal that also recalculates the
1526 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1528 * Returns 0 on success, -EERROR otherwise.
1530 int clk_set_rate(struct clk *clk, unsigned long rate)
1532 struct clk *top, *fail_clk;
1538 /* prevent racing with updates to the clock topology */
1541 /* bail early if nothing to do */
1542 if (rate == clk_get_rate(clk))
1545 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1550 /* calculate new rates and get the topmost changed clock */
1551 top = clk_calc_new_rates(clk, rate);
1557 /* notify that we are about to change rates */
1558 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1560 pr_debug("%s: failed to set %s rate\n", __func__,
1562 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1567 /* change the rates */
1568 clk_change_rate(top);
1571 clk_prepare_unlock();
1575 EXPORT_SYMBOL_GPL(clk_set_rate);
1578 * clk_get_parent - return the parent of a clk
1579 * @clk: the clk whose parent gets returned
1581 * Simply returns clk->parent. Returns NULL if clk is NULL.
1583 struct clk *clk_get_parent(struct clk *clk)
1588 parent = __clk_get_parent(clk);
1589 clk_prepare_unlock();
1593 EXPORT_SYMBOL_GPL(clk_get_parent);
1596 * .get_parent is mandatory for clocks with multiple possible parents. It is
1597 * optional for single-parent clocks. Always call .get_parent if it is
1598 * available and WARN if it is missing for multi-parent clocks.
1600 * For single-parent clocks without .get_parent, first check to see if the
1601 * .parents array exists, and if so use it to avoid an expensive tree
1602 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1604 static struct clk *__clk_init_parent(struct clk *clk)
1606 struct clk *ret = NULL;
1609 /* handle the trivial cases */
1611 if (!clk->num_parents)
1614 if (clk->num_parents == 1) {
1615 if (IS_ERR_OR_NULL(clk->parent))
1616 clk->parent = __clk_lookup(clk->parent_names[0]);
1621 if (!clk->ops->get_parent) {
1622 WARN(!clk->ops->get_parent,
1623 "%s: multi-parent clocks must implement .get_parent\n",
1629 * Do our best to cache parent clocks in clk->parents. This prevents
1630 * unnecessary and expensive calls to __clk_lookup. We don't set
1631 * clk->parent here; that is done by the calling function
1634 index = clk->ops->get_parent(clk->hw);
1638 kcalloc(clk->num_parents, sizeof(struct clk *),
1641 ret = clk_get_parent_by_index(clk, index);
1647 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1649 clk_reparent(clk, new_parent);
1650 __clk_recalc_accuracies(clk);
1651 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1655 * clk_has_parent - check if a clock is a possible parent for another
1656 * @clk: clock source
1657 * @parent: parent clock source
1659 * This function can be used in drivers that need to check that a clock can be
1660 * the parent of another without actually changing the parent.
1662 * Returns true if @parent is a possible parent for @clk, false otherwise.
1664 bool clk_has_parent(struct clk *clk, struct clk *parent)
1668 /* NULL clocks should be nops, so return success if either is NULL. */
1669 if (!clk || !parent)
1672 /* Optimize for the case where the parent is already the parent. */
1673 if (clk->parent == parent)
1676 for (i = 0; i < clk->num_parents; i++)
1677 if (strcmp(clk->parent_names[i], parent->name) == 0)
1682 EXPORT_SYMBOL_GPL(clk_has_parent);
1685 * clk_set_parent - switch the parent of a mux clk
1686 * @clk: the mux clk whose input we are switching
1687 * @parent: the new input to clk
1689 * Re-parent clk to use parent as its new input source. If clk is in
1690 * prepared state, the clk will get enabled for the duration of this call. If
1691 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1692 * that, the reparenting is glitchy in hardware, etc), use the
1693 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1695 * After successfully changing clk's parent clk_set_parent will update the
1696 * clk topology, sysfs topology and propagate rate recalculation via
1697 * __clk_recalc_rates.
1699 * Returns 0 on success, -EERROR otherwise.
1701 int clk_set_parent(struct clk *clk, struct clk *parent)
1705 unsigned long p_rate = 0;
1710 /* verify ops for for multi-parent clks */
1711 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1714 /* prevent racing with updates to the clock topology */
1717 if (clk->parent == parent)
1720 /* check that we are allowed to re-parent if the clock is in use */
1721 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1726 /* try finding the new parent index */
1728 p_index = clk_fetch_parent_index(clk, parent);
1729 p_rate = parent->rate;
1731 pr_debug("%s: clk %s can not be parent of clk %s\n",
1732 __func__, parent->name, clk->name);
1738 /* propagate PRE_RATE_CHANGE notifications */
1739 ret = __clk_speculate_rates(clk, p_rate);
1741 /* abort if a driver objects */
1742 if (ret & NOTIFY_STOP_MASK)
1745 /* do the re-parent */
1746 ret = __clk_set_parent(clk, parent, p_index);
1748 /* propagate rate an accuracy recalculation accordingly */
1750 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1752 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1753 __clk_recalc_accuracies(clk);
1757 clk_prepare_unlock();
1761 EXPORT_SYMBOL_GPL(clk_set_parent);
1764 * clk_set_phase - adjust the phase shift of a clock signal
1765 * @clk: clock signal source
1766 * @degrees: number of degrees the signal is shifted
1768 * Shifts the phase of a clock signal by the specified
1769 * degrees. Returns 0 on success, -EERROR otherwise.
1771 * This function makes no distinction about the input or reference
1772 * signal that we adjust the clock signal phase against. For example
1773 * phase locked-loop clock signal generators we may shift phase with
1774 * respect to feedback clock signal input, but for other cases the
1775 * clock phase may be shifted with respect to some other, unspecified
1778 * Additionally the concept of phase shift does not propagate through
1779 * the clock tree hierarchy, which sets it apart from clock rates and
1780 * clock accuracy. A parent clock phase attribute does not have an
1781 * impact on the phase attribute of a child clock.
1783 int clk_set_phase(struct clk *clk, int degrees)
1790 /* sanity check degrees */
1797 if (!clk->ops->set_phase)
1800 ret = clk->ops->set_phase(clk->hw, degrees);
1803 clk->phase = degrees;
1806 clk_prepare_unlock();
1813 * clk_get_phase - return the phase shift of a clock signal
1814 * @clk: clock signal source
1816 * Returns the phase shift of a clock node in degrees, otherwise returns
1819 int clk_get_phase(struct clk *clk)
1828 clk_prepare_unlock();
1835 * __clk_init - initialize the data structures in a struct clk
1836 * @dev: device initializing this clk, placeholder for now
1837 * @clk: clk being initialized
1839 * Initializes the lists in struct clk, queries the hardware for the
1840 * parent and rate and sets them both.
1842 int __clk_init(struct device *dev, struct clk *clk)
1846 struct hlist_node *tmp2;
1853 /* check to see if a clock with this name is already registered */
1854 if (__clk_lookup(clk->name)) {
1855 pr_debug("%s: clk %s already initialized\n",
1856 __func__, clk->name);
1861 /* check that clk_ops are sane. See Documentation/clk.txt */
1862 if (clk->ops->set_rate &&
1863 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1864 clk->ops->recalc_rate)) {
1865 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1866 __func__, clk->name);
1871 if (clk->ops->set_parent && !clk->ops->get_parent) {
1872 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1873 __func__, clk->name);
1878 if (clk->ops->set_rate_and_parent &&
1879 !(clk->ops->set_parent && clk->ops->set_rate)) {
1880 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
1881 __func__, clk->name);
1886 /* throw a WARN if any entries in parent_names are NULL */
1887 for (i = 0; i < clk->num_parents; i++)
1888 WARN(!clk->parent_names[i],
1889 "%s: invalid NULL in %s's .parent_names\n",
1890 __func__, clk->name);
1893 * Allocate an array of struct clk *'s to avoid unnecessary string
1894 * look-ups of clk's possible parents. This can fail for clocks passed
1895 * in to clk_init during early boot; thus any access to clk->parents[]
1896 * must always check for a NULL pointer and try to populate it if
1899 * If clk->parents is not NULL we skip this entire block. This allows
1900 * for clock drivers to statically initialize clk->parents.
1902 if (clk->num_parents > 1 && !clk->parents) {
1903 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
1906 * __clk_lookup returns NULL for parents that have not been
1907 * clk_init'd; thus any access to clk->parents[] must check
1908 * for a NULL pointer. We can always perform lazy lookups for
1909 * missing parents later on.
1912 for (i = 0; i < clk->num_parents; i++)
1914 __clk_lookup(clk->parent_names[i]);
1917 clk->parent = __clk_init_parent(clk);
1920 * Populate clk->parent if parent has already been __clk_init'd. If
1921 * parent has not yet been __clk_init'd then place clk in the orphan
1922 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1925 * Every time a new clk is clk_init'd then we walk the list of orphan
1926 * clocks and re-parent any that are children of the clock currently
1930 hlist_add_head(&clk->child_node,
1931 &clk->parent->children);
1932 else if (clk->flags & CLK_IS_ROOT)
1933 hlist_add_head(&clk->child_node, &clk_root_list);
1935 hlist_add_head(&clk->child_node, &clk_orphan_list);
1938 * Set clk's accuracy. The preferred method is to use
1939 * .recalc_accuracy. For simple clocks and lazy developers the default
1940 * fallback is to use the parent's accuracy. If a clock doesn't have a
1941 * parent (or is orphaned) then accuracy is set to zero (perfect
1944 if (clk->ops->recalc_accuracy)
1945 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1946 __clk_get_accuracy(clk->parent));
1947 else if (clk->parent)
1948 clk->accuracy = clk->parent->accuracy;
1954 * Since a phase is by definition relative to its parent, just
1955 * query the current clock phase, or just assume it's in phase.
1957 if (clk->ops->get_phase)
1958 clk->phase = clk->ops->get_phase(clk->hw);
1963 * Set clk's rate. The preferred method is to use .recalc_rate. For
1964 * simple clocks and lazy developers the default fallback is to use the
1965 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1966 * then rate is set to zero.
1968 if (clk->ops->recalc_rate)
1969 clk->rate = clk->ops->recalc_rate(clk->hw,
1970 __clk_get_rate(clk->parent));
1971 else if (clk->parent)
1972 clk->rate = clk->parent->rate;
1977 * walk the list of orphan clocks and reparent any that are children of
1980 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1981 if (orphan->num_parents && orphan->ops->get_parent) {
1982 i = orphan->ops->get_parent(orphan->hw);
1983 if (!strcmp(clk->name, orphan->parent_names[i]))
1984 __clk_reparent(orphan, clk);
1988 for (i = 0; i < orphan->num_parents; i++)
1989 if (!strcmp(clk->name, orphan->parent_names[i])) {
1990 __clk_reparent(orphan, clk);
1996 * optional platform-specific magic
1998 * The .init callback is not used by any of the basic clock types, but
1999 * exists for weird hardware that must perform initialization magic.
2000 * Please consider other ways of solving initialization problems before
2001 * using this callback, as its use is discouraged.
2004 clk->ops->init(clk->hw);
2006 kref_init(&clk->ref);
2008 clk_prepare_unlock();
2011 clk_debug_register(clk);
2017 * __clk_register - register a clock and return a cookie.
2019 * Same as clk_register, except that the .clk field inside hw shall point to a
2020 * preallocated (generally statically allocated) struct clk. None of the fields
2021 * of the struct clk need to be initialized.
2023 * The data pointed to by .init and .clk field shall NOT be marked as init
2026 * __clk_register is only exposed via clk-private.h and is intended for use with
2027 * very large numbers of clocks that need to be statically initialized. It is
2028 * a layering violation to include clk-private.h from any code which implements
2029 * a clock's .ops; as such any statically initialized clock data MUST be in a
2030 * separate C file from the logic that implements its operations. Returns 0
2031 * on success, otherwise an error code.
2033 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
2039 clk->name = hw->init->name;
2040 clk->ops = hw->init->ops;
2042 clk->flags = hw->init->flags;
2043 clk->parent_names = hw->init->parent_names;
2044 clk->num_parents = hw->init->num_parents;
2045 if (dev && dev->driver)
2046 clk->owner = dev->driver->owner;
2050 ret = __clk_init(dev, clk);
2052 return ERR_PTR(ret);
2056 EXPORT_SYMBOL_GPL(__clk_register);
2059 * clk_register - allocate a new clock, register it and return an opaque cookie
2060 * @dev: device that is registering this clock
2061 * @hw: link to hardware-specific clock data
2063 * clk_register is the primary interface for populating the clock tree with new
2064 * clock nodes. It returns a pointer to the newly allocated struct clk which
2065 * cannot be dereferenced by driver code but may be used in conjuction with the
2066 * rest of the clock API. In the event of an error clk_register will return an
2067 * error code; drivers must test for an error code after calling clk_register.
2069 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
2074 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2076 pr_err("%s: could not allocate clk\n", __func__);
2081 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
2083 pr_err("%s: could not allocate clk->name\n", __func__);
2087 clk->ops = hw->init->ops;
2088 if (dev && dev->driver)
2089 clk->owner = dev->driver->owner;
2091 clk->flags = hw->init->flags;
2092 clk->num_parents = hw->init->num_parents;
2095 /* allocate local copy in case parent_names is __initdata */
2096 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
2099 if (!clk->parent_names) {
2100 pr_err("%s: could not allocate clk->parent_names\n", __func__);
2102 goto fail_parent_names;
2106 /* copy each string name in case parent_names is __initdata */
2107 for (i = 0; i < clk->num_parents; i++) {
2108 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
2110 if (!clk->parent_names[i]) {
2111 pr_err("%s: could not copy parent_names\n", __func__);
2113 goto fail_parent_names_copy;
2117 ret = __clk_init(dev, clk);
2121 fail_parent_names_copy:
2123 kfree(clk->parent_names[i]);
2124 kfree(clk->parent_names);
2130 return ERR_PTR(ret);
2132 EXPORT_SYMBOL_GPL(clk_register);
2135 * Free memory allocated for a clock.
2136 * Caller must hold prepare_lock.
2138 static void __clk_release(struct kref *ref)
2140 struct clk *clk = container_of(ref, struct clk, ref);
2141 int i = clk->num_parents;
2143 kfree(clk->parents);
2145 kfree(clk->parent_names[i]);
2147 kfree(clk->parent_names);
2153 * Empty clk_ops for unregistered clocks. These are used temporarily
2154 * after clk_unregister() was called on a clock and until last clock
2155 * consumer calls clk_put() and the struct clk object is freed.
2157 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2162 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2167 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2168 unsigned long parent_rate)
2173 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2178 static const struct clk_ops clk_nodrv_ops = {
2179 .enable = clk_nodrv_prepare_enable,
2180 .disable = clk_nodrv_disable_unprepare,
2181 .prepare = clk_nodrv_prepare_enable,
2182 .unprepare = clk_nodrv_disable_unprepare,
2183 .set_rate = clk_nodrv_set_rate,
2184 .set_parent = clk_nodrv_set_parent,
2188 * clk_unregister - unregister a currently registered clock
2189 * @clk: clock to unregister
2191 void clk_unregister(struct clk *clk)
2193 unsigned long flags;
2195 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2198 clk_debug_unregister(clk);
2202 if (clk->ops == &clk_nodrv_ops) {
2203 pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
2207 * Assign empty clock ops for consumers that might still hold
2208 * a reference to this clock.
2210 flags = clk_enable_lock();
2211 clk->ops = &clk_nodrv_ops;
2212 clk_enable_unlock(flags);
2214 if (!hlist_empty(&clk->children)) {
2216 struct hlist_node *t;
2218 /* Reparent all children to the orphan list. */
2219 hlist_for_each_entry_safe(child, t, &clk->children, child_node)
2220 clk_set_parent(child, NULL);
2223 hlist_del_init(&clk->child_node);
2225 if (clk->prepare_count)
2226 pr_warn("%s: unregistering prepared clock: %s\n",
2227 __func__, clk->name);
2228 kref_put(&clk->ref, __clk_release);
2230 clk_prepare_unlock();
2232 EXPORT_SYMBOL_GPL(clk_unregister);
2234 static void devm_clk_release(struct device *dev, void *res)
2236 clk_unregister(*(struct clk **)res);
2240 * devm_clk_register - resource managed clk_register()
2241 * @dev: device that is registering this clock
2242 * @hw: link to hardware-specific clock data
2244 * Managed clk_register(). Clocks returned from this function are
2245 * automatically clk_unregister()ed on driver detach. See clk_register() for
2248 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2253 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2255 return ERR_PTR(-ENOMEM);
2257 clk = clk_register(dev, hw);
2260 devres_add(dev, clkp);
2267 EXPORT_SYMBOL_GPL(devm_clk_register);
2269 static int devm_clk_match(struct device *dev, void *res, void *data)
2271 struct clk *c = res;
2278 * devm_clk_unregister - resource managed clk_unregister()
2279 * @clk: clock to unregister
2281 * Deallocate a clock allocated with devm_clk_register(). Normally
2282 * this function will not need to be called and the resource management
2283 * code will ensure that the resource is freed.
2285 void devm_clk_unregister(struct device *dev, struct clk *clk)
2287 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2289 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2294 int __clk_get(struct clk *clk)
2297 if (!try_module_get(clk->owner))
2300 kref_get(&clk->ref);
2305 void __clk_put(struct clk *clk)
2307 struct module *owner;
2309 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2314 kref_put(&clk->ref, __clk_release);
2315 clk_prepare_unlock();
2320 /*** clk rate change notifiers ***/
2323 * clk_notifier_register - add a clk rate change notifier
2324 * @clk: struct clk * to watch
2325 * @nb: struct notifier_block * with callback info
2327 * Request notification when clk's rate changes. This uses an SRCU
2328 * notifier because we want it to block and notifier unregistrations are
2329 * uncommon. The callbacks associated with the notifier must not
2330 * re-enter into the clk framework by calling any top-level clk APIs;
2331 * this will cause a nested prepare_lock mutex.
2333 * In all notification cases cases (pre, post and abort rate change) the
2334 * original clock rate is passed to the callback via struct
2335 * clk_notifier_data.old_rate and the new frequency is passed via struct
2336 * clk_notifier_data.new_rate.
2338 * clk_notifier_register() must be called from non-atomic context.
2339 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2340 * allocation failure; otherwise, passes along the return value of
2341 * srcu_notifier_chain_register().
2343 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2345 struct clk_notifier *cn;
2353 /* search the list of notifiers for this clk */
2354 list_for_each_entry(cn, &clk_notifier_list, node)
2358 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2359 if (cn->clk != clk) {
2360 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2365 srcu_init_notifier_head(&cn->notifier_head);
2367 list_add(&cn->node, &clk_notifier_list);
2370 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2372 clk->notifier_count++;
2375 clk_prepare_unlock();
2379 EXPORT_SYMBOL_GPL(clk_notifier_register);
2382 * clk_notifier_unregister - remove a clk rate change notifier
2383 * @clk: struct clk *
2384 * @nb: struct notifier_block * with callback info
2386 * Request no further notification for changes to 'clk' and frees memory
2387 * allocated in clk_notifier_register.
2389 * Returns -EINVAL if called with null arguments; otherwise, passes
2390 * along the return value of srcu_notifier_chain_unregister().
2392 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2394 struct clk_notifier *cn = NULL;
2402 list_for_each_entry(cn, &clk_notifier_list, node)
2406 if (cn->clk == clk) {
2407 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2409 clk->notifier_count--;
2411 /* XXX the notifier code should handle this better */
2412 if (!cn->notifier_head.head) {
2413 srcu_cleanup_notifier_head(&cn->notifier_head);
2414 list_del(&cn->node);
2422 clk_prepare_unlock();
2426 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2430 * struct of_clk_provider - Clock provider registration structure
2431 * @link: Entry in global list of clock providers
2432 * @node: Pointer to device tree node of clock provider
2433 * @get: Get clock callback. Returns NULL or a struct clk for the
2434 * given clock specifier
2435 * @data: context pointer to be passed into @get callback
2437 struct of_clk_provider {
2438 struct list_head link;
2440 struct device_node *node;
2441 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2445 static const struct of_device_id __clk_of_table_sentinel
2446 __used __section(__clk_of_table_end);
2448 static LIST_HEAD(of_clk_providers);
2449 static DEFINE_MUTEX(of_clk_mutex);
2451 /* of_clk_provider list locking helpers */
2452 void of_clk_lock(void)
2454 mutex_lock(&of_clk_mutex);
2457 void of_clk_unlock(void)
2459 mutex_unlock(&of_clk_mutex);
2462 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2467 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2469 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2471 struct clk_onecell_data *clk_data = data;
2472 unsigned int idx = clkspec->args[0];
2474 if (idx >= clk_data->clk_num) {
2475 pr_err("%s: invalid clock index %d\n", __func__, idx);
2476 return ERR_PTR(-EINVAL);
2479 return clk_data->clks[idx];
2481 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2484 * of_clk_add_provider() - Register a clock provider for a node
2485 * @np: Device node pointer associated with clock provider
2486 * @clk_src_get: callback for decoding clock
2487 * @data: context pointer for @clk_src_get callback.
2489 int of_clk_add_provider(struct device_node *np,
2490 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2494 struct of_clk_provider *cp;
2497 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2501 cp->node = of_node_get(np);
2503 cp->get = clk_src_get;
2505 mutex_lock(&of_clk_mutex);
2506 list_add(&cp->link, &of_clk_providers);
2507 mutex_unlock(&of_clk_mutex);
2508 pr_debug("Added clock from %s\n", np->full_name);
2510 ret = of_clk_set_defaults(np, true);
2512 of_clk_del_provider(np);
2516 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2519 * of_clk_del_provider() - Remove a previously registered clock provider
2520 * @np: Device node pointer associated with clock provider
2522 void of_clk_del_provider(struct device_node *np)
2524 struct of_clk_provider *cp;
2526 mutex_lock(&of_clk_mutex);
2527 list_for_each_entry(cp, &of_clk_providers, link) {
2528 if (cp->node == np) {
2529 list_del(&cp->link);
2530 of_node_put(cp->node);
2535 mutex_unlock(&of_clk_mutex);
2537 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2539 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec)
2541 struct of_clk_provider *provider;
2542 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2544 /* Check if we have such a provider in our array */
2545 list_for_each_entry(provider, &of_clk_providers, link) {
2546 if (provider->node == clkspec->np)
2547 clk = provider->get(clkspec, provider->data);
2555 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2559 mutex_lock(&of_clk_mutex);
2560 clk = __of_clk_get_from_provider(clkspec);
2561 mutex_unlock(&of_clk_mutex);
2566 int of_clk_get_parent_count(struct device_node *np)
2568 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2570 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2572 const char *of_clk_get_parent_name(struct device_node *np, int index)
2574 struct of_phandle_args clkspec;
2575 struct property *prop;
2576 const char *clk_name;
2585 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2590 index = clkspec.args_count ? clkspec.args[0] : 0;
2593 /* if there is an indices property, use it to transfer the index
2594 * specified into an array offset for the clock-output-names property.
2596 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
2604 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2607 clk_name = clkspec.np->name;
2609 of_node_put(clkspec.np);
2612 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2614 struct clock_provider {
2615 of_clk_init_cb_t clk_init_cb;
2616 struct device_node *np;
2617 struct list_head node;
2620 static LIST_HEAD(clk_provider_list);
2623 * This function looks for a parent clock. If there is one, then it
2624 * checks that the provider for this parent clock was initialized, in
2625 * this case the parent clock will be ready.
2627 static int parent_ready(struct device_node *np)
2632 struct clk *clk = of_clk_get(np, i);
2634 /* this parent is ready we can check the next one */
2641 /* at least one parent is not ready, we exit now */
2642 if (PTR_ERR(clk) == -EPROBE_DEFER)
2646 * Here we make assumption that the device tree is
2647 * written correctly. So an error means that there is
2648 * no more parent. As we didn't exit yet, then the
2649 * previous parent are ready. If there is no clock
2650 * parent, no need to wait for them, then we can
2651 * consider their absence as being ready
2658 * of_clk_init() - Scan and init clock providers from the DT
2659 * @matches: array of compatible values and init functions for providers.
2661 * This function scans the device tree for matching clock providers
2662 * and calls their initialization functions. It also does it by trying
2663 * to follow the dependencies.
2665 void __init of_clk_init(const struct of_device_id *matches)
2667 const struct of_device_id *match;
2668 struct device_node *np;
2669 struct clock_provider *clk_provider, *next;
2674 matches = &__clk_of_table;
2676 /* First prepare the list of the clocks providers */
2677 for_each_matching_node_and_match(np, matches, &match) {
2678 struct clock_provider *parent =
2679 kzalloc(sizeof(struct clock_provider), GFP_KERNEL);
2681 parent->clk_init_cb = match->data;
2683 list_add_tail(&parent->node, &clk_provider_list);
2686 while (!list_empty(&clk_provider_list)) {
2687 is_init_done = false;
2688 list_for_each_entry_safe(clk_provider, next,
2689 &clk_provider_list, node) {
2690 if (force || parent_ready(clk_provider->np)) {
2692 clk_provider->clk_init_cb(clk_provider->np);
2693 of_clk_set_defaults(clk_provider->np, true);
2695 list_del(&clk_provider->node);
2696 kfree(clk_provider);
2697 is_init_done = true;
2702 * We didn't manage to initialize any of the
2703 * remaining providers during the last loop, so now we
2704 * initialize all the remaining ones unconditionally
2705 * in case the clock parent was not mandatory