2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
12 #include <linux/clk-private.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock.h>
16 #include <linux/err.h>
17 #include <linux/list.h>
18 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
26 static DEFINE_SPINLOCK(enable_lock);
27 static DEFINE_MUTEX(prepare_lock);
29 static struct task_struct *prepare_owner;
30 static struct task_struct *enable_owner;
32 static int prepare_refcnt;
33 static int enable_refcnt;
35 static HLIST_HEAD(clk_root_list);
36 static HLIST_HEAD(clk_orphan_list);
37 static LIST_HEAD(clk_notifier_list);
40 static void clk_prepare_lock(void)
42 if (!mutex_trylock(&prepare_lock)) {
43 if (prepare_owner == current) {
47 mutex_lock(&prepare_lock);
49 WARN_ON_ONCE(prepare_owner != NULL);
50 WARN_ON_ONCE(prepare_refcnt != 0);
51 prepare_owner = current;
55 static void clk_prepare_unlock(void)
57 WARN_ON_ONCE(prepare_owner != current);
58 WARN_ON_ONCE(prepare_refcnt == 0);
63 mutex_unlock(&prepare_lock);
66 static unsigned long clk_enable_lock(void)
70 if (!spin_trylock_irqsave(&enable_lock, flags)) {
71 if (enable_owner == current) {
75 spin_lock_irqsave(&enable_lock, flags);
77 WARN_ON_ONCE(enable_owner != NULL);
78 WARN_ON_ONCE(enable_refcnt != 0);
79 enable_owner = current;
84 static void clk_enable_unlock(unsigned long flags)
86 WARN_ON_ONCE(enable_owner != current);
87 WARN_ON_ONCE(enable_refcnt == 0);
92 spin_unlock_irqrestore(&enable_lock, flags);
95 /*** debugfs support ***/
97 #ifdef CONFIG_DEBUG_FS
98 #include <linux/debugfs.h>
100 static struct dentry *rootdir;
101 static struct dentry *orphandir;
102 static int inited = 0;
104 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
109 seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu\n",
111 30 - level * 3, c->name,
112 c->enable_count, c->prepare_count, clk_get_rate(c),
113 clk_get_accuracy(c));
116 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
124 clk_summary_show_one(s, c, level);
126 hlist_for_each_entry(child, &c->children, child_node)
127 clk_summary_show_subtree(s, child, level + 1);
130 static int clk_summary_show(struct seq_file *s, void *data)
134 seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy\n");
135 seq_puts(s, "--------------------------------------------------------------------------------\n");
139 hlist_for_each_entry(c, &clk_root_list, child_node)
140 clk_summary_show_subtree(s, c, 0);
142 hlist_for_each_entry(c, &clk_orphan_list, child_node)
143 clk_summary_show_subtree(s, c, 0);
145 clk_prepare_unlock();
151 static int clk_summary_open(struct inode *inode, struct file *file)
153 return single_open(file, clk_summary_show, inode->i_private);
156 static const struct file_operations clk_summary_fops = {
157 .open = clk_summary_open,
160 .release = single_release,
163 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
168 seq_printf(s, "\"%s\": { ", c->name);
169 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
170 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
171 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
172 seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
175 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
182 clk_dump_one(s, c, level);
184 hlist_for_each_entry(child, &c->children, child_node) {
186 clk_dump_subtree(s, child, level + 1);
192 static int clk_dump(struct seq_file *s, void *data)
195 bool first_node = true;
201 hlist_for_each_entry(c, &clk_root_list, child_node) {
205 clk_dump_subtree(s, c, 0);
208 hlist_for_each_entry(c, &clk_orphan_list, child_node) {
210 clk_dump_subtree(s, c, 0);
213 clk_prepare_unlock();
220 static int clk_dump_open(struct inode *inode, struct file *file)
222 return single_open(file, clk_dump, inode->i_private);
225 static const struct file_operations clk_dump_fops = {
226 .open = clk_dump_open,
229 .release = single_release,
232 /* caller must hold prepare_lock */
233 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
238 if (!clk || !pdentry) {
243 d = debugfs_create_dir(clk->name, pdentry);
249 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
254 d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
255 (u32 *)&clk->accuracy);
259 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
264 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
265 (u32 *)&clk->prepare_count);
269 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
270 (u32 *)&clk->enable_count);
274 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
275 (u32 *)&clk->notifier_count);
279 if (clk->ops->debug_init)
280 if (clk->ops->debug_init(clk->hw, clk->dentry))
287 debugfs_remove_recursive(clk->dentry);
293 /* caller must hold prepare_lock */
294 static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
299 if (!clk || !pdentry)
302 ret = clk_debug_create_one(clk, pdentry);
307 hlist_for_each_entry(child, &clk->children, child_node)
308 clk_debug_create_subtree(child, clk->dentry);
316 * clk_debug_register - add a clk node to the debugfs clk tree
317 * @clk: the clk being added to the debugfs clk tree
319 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
320 * initialized. Otherwise it bails out early since the debugfs clk tree
321 * will be created lazily by clk_debug_init as part of a late_initcall.
323 * Caller must hold prepare_lock. Only clk_init calls this function (so
324 * far) so this is taken care.
326 static int clk_debug_register(struct clk *clk)
329 struct dentry *pdentry;
335 parent = clk->parent;
338 * Check to see if a clk is a root clk. Also check that it is
339 * safe to add this clk to debugfs
342 if (clk->flags & CLK_IS_ROOT)
348 pdentry = parent->dentry;
352 ret = clk_debug_create_subtree(clk, pdentry);
359 * clk_debug_unregister - remove a clk node from the debugfs clk tree
360 * @clk: the clk being removed from the debugfs clk tree
362 * Dynamically removes a clk and all it's children clk nodes from the
363 * debugfs clk tree if clk->dentry points to debugfs created by
364 * clk_debug_register in __clk_init.
366 * Caller must hold prepare_lock.
368 static void clk_debug_unregister(struct clk *clk)
370 debugfs_remove_recursive(clk->dentry);
374 * clk_debug_reparent - reparent clk node in the debugfs clk tree
375 * @clk: the clk being reparented
376 * @new_parent: the new clk parent, may be NULL
378 * Rename clk entry in the debugfs clk tree if debugfs has been
379 * initialized. Otherwise it bails out early since the debugfs clk tree
380 * will be created lazily by clk_debug_init as part of a late_initcall.
382 * Caller must hold prepare_lock.
384 static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
387 struct dentry *new_parent_d;
393 new_parent_d = new_parent->dentry;
395 new_parent_d = orphandir;
397 d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
398 new_parent_d, clk->name);
402 pr_debug("%s: failed to rename debugfs entry for %s\n",
403 __func__, clk->name);
407 * clk_debug_init - lazily create the debugfs clk tree visualization
409 * clks are often initialized very early during boot before memory can
410 * be dynamically allocated and well before debugfs is setup.
411 * clk_debug_init walks the clk tree hierarchy while holding
412 * prepare_lock and creates the topology as part of a late_initcall,
413 * thus insuring that clks initialized very early will still be
414 * represented in the debugfs clk tree. This function should only be
415 * called once at boot-time, and all other clks added dynamically will
416 * be done so with clk_debug_register.
418 static int __init clk_debug_init(void)
423 rootdir = debugfs_create_dir("clk", NULL);
428 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
433 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
438 orphandir = debugfs_create_dir("orphans", rootdir);
445 hlist_for_each_entry(clk, &clk_root_list, child_node)
446 clk_debug_create_subtree(clk, rootdir);
448 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
449 clk_debug_create_subtree(clk, orphandir);
453 clk_prepare_unlock();
457 late_initcall(clk_debug_init);
459 static inline int clk_debug_register(struct clk *clk) { return 0; }
460 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
463 static inline void clk_debug_unregister(struct clk *clk)
468 /* caller must hold prepare_lock */
469 static void clk_unprepare_unused_subtree(struct clk *clk)
476 hlist_for_each_entry(child, &clk->children, child_node)
477 clk_unprepare_unused_subtree(child);
479 if (clk->prepare_count)
482 if (clk->flags & CLK_IGNORE_UNUSED)
485 if (__clk_is_prepared(clk)) {
486 if (clk->ops->unprepare_unused)
487 clk->ops->unprepare_unused(clk->hw);
488 else if (clk->ops->unprepare)
489 clk->ops->unprepare(clk->hw);
493 /* caller must hold prepare_lock */
494 static void clk_disable_unused_subtree(struct clk *clk)
502 hlist_for_each_entry(child, &clk->children, child_node)
503 clk_disable_unused_subtree(child);
505 flags = clk_enable_lock();
507 if (clk->enable_count)
510 if (clk->flags & CLK_IGNORE_UNUSED)
514 * some gate clocks have special needs during the disable-unused
515 * sequence. call .disable_unused if available, otherwise fall
518 if (__clk_is_enabled(clk)) {
519 if (clk->ops->disable_unused)
520 clk->ops->disable_unused(clk->hw);
521 else if (clk->ops->disable)
522 clk->ops->disable(clk->hw);
526 clk_enable_unlock(flags);
532 static bool clk_ignore_unused;
533 static int __init clk_ignore_unused_setup(char *__unused)
535 clk_ignore_unused = true;
538 __setup("clk_ignore_unused", clk_ignore_unused_setup);
540 static int clk_disable_unused(void)
544 if (clk_ignore_unused) {
545 pr_warn("clk: Not disabling unused clocks\n");
551 hlist_for_each_entry(clk, &clk_root_list, child_node)
552 clk_disable_unused_subtree(clk);
554 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
555 clk_disable_unused_subtree(clk);
557 hlist_for_each_entry(clk, &clk_root_list, child_node)
558 clk_unprepare_unused_subtree(clk);
560 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
561 clk_unprepare_unused_subtree(clk);
563 clk_prepare_unlock();
567 late_initcall_sync(clk_disable_unused);
569 /*** helper functions ***/
571 const char *__clk_get_name(struct clk *clk)
573 return !clk ? NULL : clk->name;
575 EXPORT_SYMBOL_GPL(__clk_get_name);
577 struct clk_hw *__clk_get_hw(struct clk *clk)
579 return !clk ? NULL : clk->hw;
581 EXPORT_SYMBOL_GPL(__clk_get_hw);
583 u8 __clk_get_num_parents(struct clk *clk)
585 return !clk ? 0 : clk->num_parents;
587 EXPORT_SYMBOL_GPL(__clk_get_num_parents);
589 struct clk *__clk_get_parent(struct clk *clk)
591 return !clk ? NULL : clk->parent;
593 EXPORT_SYMBOL_GPL(__clk_get_parent);
595 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
597 if (!clk || index >= clk->num_parents)
599 else if (!clk->parents)
600 return __clk_lookup(clk->parent_names[index]);
601 else if (!clk->parents[index])
602 return clk->parents[index] =
603 __clk_lookup(clk->parent_names[index]);
605 return clk->parents[index];
607 EXPORT_SYMBOL_GPL(clk_get_parent_by_index);
609 unsigned int __clk_get_enable_count(struct clk *clk)
611 return !clk ? 0 : clk->enable_count;
614 unsigned int __clk_get_prepare_count(struct clk *clk)
616 return !clk ? 0 : clk->prepare_count;
619 unsigned long __clk_get_rate(struct clk *clk)
630 if (clk->flags & CLK_IS_ROOT)
639 EXPORT_SYMBOL_GPL(__clk_get_rate);
641 unsigned long __clk_get_accuracy(struct clk *clk)
646 return clk->accuracy;
649 unsigned long __clk_get_flags(struct clk *clk)
651 return !clk ? 0 : clk->flags;
653 EXPORT_SYMBOL_GPL(__clk_get_flags);
655 bool __clk_is_prepared(struct clk *clk)
663 * .is_prepared is optional for clocks that can prepare
664 * fall back to software usage counter if it is missing
666 if (!clk->ops->is_prepared) {
667 ret = clk->prepare_count ? 1 : 0;
671 ret = clk->ops->is_prepared(clk->hw);
676 bool __clk_is_enabled(struct clk *clk)
684 * .is_enabled is only mandatory for clocks that gate
685 * fall back to software usage counter if .is_enabled is missing
687 if (!clk->ops->is_enabled) {
688 ret = clk->enable_count ? 1 : 0;
692 ret = clk->ops->is_enabled(clk->hw);
696 EXPORT_SYMBOL_GPL(__clk_is_enabled);
698 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
703 if (!strcmp(clk->name, name))
706 hlist_for_each_entry(child, &clk->children, child_node) {
707 ret = __clk_lookup_subtree(name, child);
715 struct clk *__clk_lookup(const char *name)
717 struct clk *root_clk;
723 /* search the 'proper' clk tree first */
724 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
725 ret = __clk_lookup_subtree(name, root_clk);
730 /* if not found, then search the orphan tree */
731 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
732 ret = __clk_lookup_subtree(name, root_clk);
741 * Helper for finding best parent to provide a given frequency. This can be used
742 * directly as a determine_rate callback (e.g. for a mux), or from a more
743 * complex clock that may combine a mux with other operations.
745 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
746 unsigned long *best_parent_rate,
747 struct clk **best_parent_p)
749 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
751 unsigned long parent_rate, best = 0;
753 /* if NO_REPARENT flag set, pass through to current parent */
754 if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
755 parent = clk->parent;
756 if (clk->flags & CLK_SET_RATE_PARENT)
757 best = __clk_round_rate(parent, rate);
759 best = __clk_get_rate(parent);
761 best = __clk_get_rate(clk);
765 /* find the parent that can provide the fastest rate <= rate */
766 num_parents = clk->num_parents;
767 for (i = 0; i < num_parents; i++) {
768 parent = clk_get_parent_by_index(clk, i);
771 if (clk->flags & CLK_SET_RATE_PARENT)
772 parent_rate = __clk_round_rate(parent, rate);
774 parent_rate = __clk_get_rate(parent);
775 if (parent_rate <= rate && parent_rate > best) {
776 best_parent = parent;
783 *best_parent_p = best_parent;
784 *best_parent_rate = best;
788 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
792 void __clk_unprepare(struct clk *clk)
797 if (WARN_ON(clk->prepare_count == 0))
800 if (--clk->prepare_count > 0)
803 WARN_ON(clk->enable_count > 0);
805 if (clk->ops->unprepare)
806 clk->ops->unprepare(clk->hw);
808 __clk_unprepare(clk->parent);
812 * clk_unprepare - undo preparation of a clock source
813 * @clk: the clk being unprepared
815 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
816 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
817 * if the operation may sleep. One example is a clk which is accessed over
818 * I2c. In the complex case a clk gate operation may require a fast and a slow
819 * part. It is this reason that clk_unprepare and clk_disable are not mutually
820 * exclusive. In fact clk_disable must be called before clk_unprepare.
822 void clk_unprepare(struct clk *clk)
824 if (IS_ERR_OR_NULL(clk))
828 __clk_unprepare(clk);
829 clk_prepare_unlock();
831 EXPORT_SYMBOL_GPL(clk_unprepare);
833 int __clk_prepare(struct clk *clk)
840 if (clk->prepare_count == 0) {
841 ret = __clk_prepare(clk->parent);
845 if (clk->ops->prepare) {
846 ret = clk->ops->prepare(clk->hw);
848 __clk_unprepare(clk->parent);
854 clk->prepare_count++;
860 * clk_prepare - prepare a clock source
861 * @clk: the clk being prepared
863 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
864 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
865 * operation may sleep. One example is a clk which is accessed over I2c. In
866 * the complex case a clk ungate operation may require a fast and a slow part.
867 * It is this reason that clk_prepare and clk_enable are not mutually
868 * exclusive. In fact clk_prepare must be called before clk_enable.
869 * Returns 0 on success, -EERROR otherwise.
871 int clk_prepare(struct clk *clk)
876 ret = __clk_prepare(clk);
877 clk_prepare_unlock();
881 EXPORT_SYMBOL_GPL(clk_prepare);
883 static void __clk_disable(struct clk *clk)
888 if (WARN_ON(clk->enable_count == 0))
891 if (--clk->enable_count > 0)
894 if (clk->ops->disable)
895 clk->ops->disable(clk->hw);
897 __clk_disable(clk->parent);
901 * clk_disable - gate a clock
902 * @clk: the clk being gated
904 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
905 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
906 * clk if the operation is fast and will never sleep. One example is a
907 * SoC-internal clk which is controlled via simple register writes. In the
908 * complex case a clk gate operation may require a fast and a slow part. It is
909 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
910 * In fact clk_disable must be called before clk_unprepare.
912 void clk_disable(struct clk *clk)
916 if (IS_ERR_OR_NULL(clk))
919 flags = clk_enable_lock();
921 clk_enable_unlock(flags);
923 EXPORT_SYMBOL_GPL(clk_disable);
925 static int __clk_enable(struct clk *clk)
932 if (WARN_ON(clk->prepare_count == 0))
935 if (clk->enable_count == 0) {
936 ret = __clk_enable(clk->parent);
941 if (clk->ops->enable) {
942 ret = clk->ops->enable(clk->hw);
944 __clk_disable(clk->parent);
955 * clk_enable - ungate a clock
956 * @clk: the clk being ungated
958 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
959 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
960 * if the operation will never sleep. One example is a SoC-internal clk which
961 * is controlled via simple register writes. In the complex case a clk ungate
962 * operation may require a fast and a slow part. It is this reason that
963 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
964 * must be called before clk_enable. Returns 0 on success, -EERROR
967 int clk_enable(struct clk *clk)
972 flags = clk_enable_lock();
973 ret = __clk_enable(clk);
974 clk_enable_unlock(flags);
978 EXPORT_SYMBOL_GPL(clk_enable);
981 * __clk_round_rate - round the given rate for a clk
982 * @clk: round the rate of this clock
983 * @rate: the rate which is to be rounded
985 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
987 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
989 unsigned long parent_rate = 0;
995 parent = clk->parent;
997 parent_rate = parent->rate;
999 if (clk->ops->determine_rate)
1000 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
1002 else if (clk->ops->round_rate)
1003 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
1004 else if (clk->flags & CLK_SET_RATE_PARENT)
1005 return __clk_round_rate(clk->parent, rate);
1009 EXPORT_SYMBOL_GPL(__clk_round_rate);
1012 * clk_round_rate - round the given rate for a clk
1013 * @clk: the clk for which we are rounding a rate
1014 * @rate: the rate which is to be rounded
1016 * Takes in a rate as input and rounds it to a rate that the clk can actually
1017 * use which is then returned. If clk doesn't support round_rate operation
1018 * then the parent rate is returned.
1020 long clk_round_rate(struct clk *clk, unsigned long rate)
1025 ret = __clk_round_rate(clk, rate);
1026 clk_prepare_unlock();
1030 EXPORT_SYMBOL_GPL(clk_round_rate);
1033 * __clk_notify - call clk notifier chain
1034 * @clk: struct clk * that is changing rate
1035 * @msg: clk notifier type (see include/linux/clk.h)
1036 * @old_rate: old clk rate
1037 * @new_rate: new clk rate
1039 * Triggers a notifier call chain on the clk rate-change notification
1040 * for 'clk'. Passes a pointer to the struct clk and the previous
1041 * and current rates to the notifier callback. Intended to be called by
1042 * internal clock code only. Returns NOTIFY_DONE from the last driver
1043 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
1044 * a driver returns that.
1046 static int __clk_notify(struct clk *clk, unsigned long msg,
1047 unsigned long old_rate, unsigned long new_rate)
1049 struct clk_notifier *cn;
1050 struct clk_notifier_data cnd;
1051 int ret = NOTIFY_DONE;
1054 cnd.old_rate = old_rate;
1055 cnd.new_rate = new_rate;
1057 list_for_each_entry(cn, &clk_notifier_list, node) {
1058 if (cn->clk == clk) {
1059 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1069 * __clk_recalc_accuracies
1070 * @clk: first clk in the subtree
1072 * Walks the subtree of clks starting with clk and recalculates accuracies as
1073 * it goes. Note that if a clk does not implement the .recalc_accuracy
1074 * callback then it is assumed that the clock will take on the accuracy of it's
1077 * Caller must hold prepare_lock.
1079 static void __clk_recalc_accuracies(struct clk *clk)
1081 unsigned long parent_accuracy = 0;
1085 parent_accuracy = clk->parent->accuracy;
1087 if (clk->ops->recalc_accuracy)
1088 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1091 clk->accuracy = parent_accuracy;
1093 hlist_for_each_entry(child, &clk->children, child_node)
1094 __clk_recalc_accuracies(child);
1098 * clk_get_accuracy - return the accuracy of clk
1099 * @clk: the clk whose accuracy is being returned
1101 * Simply returns the cached accuracy of the clk, unless
1102 * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
1104 * If clk is NULL then returns 0.
1106 long clk_get_accuracy(struct clk *clk)
1108 unsigned long accuracy;
1111 if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
1112 __clk_recalc_accuracies(clk);
1114 accuracy = __clk_get_accuracy(clk);
1115 clk_prepare_unlock();
1119 EXPORT_SYMBOL_GPL(clk_get_accuracy);
1121 static unsigned long clk_recalc(struct clk *clk, unsigned long parent_rate)
1123 if (clk->ops->recalc_rate)
1124 return clk->ops->recalc_rate(clk->hw, parent_rate);
1129 * __clk_recalc_rates
1130 * @clk: first clk in the subtree
1131 * @msg: notification type (see include/linux/clk.h)
1133 * Walks the subtree of clks starting with clk and recalculates rates as it
1134 * goes. Note that if a clk does not implement the .recalc_rate callback then
1135 * it is assumed that the clock will take on the rate of its parent.
1137 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1140 * Caller must hold prepare_lock.
1142 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
1144 unsigned long old_rate;
1145 unsigned long parent_rate = 0;
1148 old_rate = clk->rate;
1151 parent_rate = clk->parent->rate;
1153 clk->rate = clk_recalc(clk, parent_rate);
1156 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1157 * & ABORT_RATE_CHANGE notifiers
1159 if (clk->notifier_count && msg)
1160 __clk_notify(clk, msg, old_rate, clk->rate);
1162 hlist_for_each_entry(child, &clk->children, child_node)
1163 __clk_recalc_rates(child, msg);
1167 * clk_get_rate - return the rate of clk
1168 * @clk: the clk whose rate is being returned
1170 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1171 * is set, which means a recalc_rate will be issued.
1172 * If clk is NULL then returns 0.
1174 unsigned long clk_get_rate(struct clk *clk)
1180 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1181 __clk_recalc_rates(clk, 0);
1183 rate = __clk_get_rate(clk);
1184 clk_prepare_unlock();
1188 EXPORT_SYMBOL_GPL(clk_get_rate);
1190 static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1194 if (!clk->parents) {
1195 clk->parents = kcalloc(clk->num_parents,
1196 sizeof(struct clk *), GFP_KERNEL);
1202 * find index of new parent clock using cached parent ptrs,
1203 * or if not yet cached, use string name comparison and cache
1204 * them now to avoid future calls to __clk_lookup.
1206 for (i = 0; i < clk->num_parents; i++) {
1207 if (clk->parents[i] == parent)
1210 if (clk->parents[i])
1213 if (!strcmp(clk->parent_names[i], parent->name)) {
1214 clk->parents[i] = __clk_lookup(parent->name);
1222 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1224 hlist_del(&clk->child_node);
1227 /* avoid duplicate POST_RATE_CHANGE notifications */
1228 if (new_parent->new_child == clk)
1229 new_parent->new_child = NULL;
1231 hlist_add_head(&clk->child_node, &new_parent->children);
1233 hlist_add_head(&clk->child_node, &clk_orphan_list);
1236 clk->parent = new_parent;
1239 static struct clk *__clk_set_parent_before(struct clk *clk, struct clk *parent)
1241 unsigned long flags;
1242 struct clk *old_parent = clk->parent;
1245 * Migrate prepare state between parents and prevent race with
1248 * If the clock is not prepared, then a race with
1249 * clk_enable/disable() is impossible since we already have the
1250 * prepare lock (future calls to clk_enable() need to be preceded by
1253 * If the clock is prepared, migrate the prepared state to the new
1254 * parent and also protect against a race with clk_enable() by
1255 * forcing the clock and the new parent on. This ensures that all
1256 * future calls to clk_enable() are practically NOPs with respect to
1257 * hardware and software states.
1259 * See also: Comment for clk_set_parent() below.
1261 if (clk->prepare_count) {
1262 __clk_prepare(parent);
1267 /* update the clk tree topology */
1268 flags = clk_enable_lock();
1269 clk_reparent(clk, parent);
1270 clk_enable_unlock(flags);
1275 static void __clk_set_parent_after(struct clk *clk, struct clk *parent,
1276 struct clk *old_parent)
1279 * Finish the migration of prepare state and undo the changes done
1280 * for preventing a race with clk_enable().
1282 if (clk->prepare_count) {
1284 clk_disable(old_parent);
1285 __clk_unprepare(old_parent);
1288 /* update debugfs with new clk tree topology */
1289 clk_debug_reparent(clk, parent);
1292 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1294 unsigned long flags;
1296 struct clk *old_parent;
1298 old_parent = __clk_set_parent_before(clk, parent);
1300 /* change clock input source */
1301 if (parent && clk->ops->set_parent)
1302 ret = clk->ops->set_parent(clk->hw, p_index);
1305 flags = clk_enable_lock();
1306 clk_reparent(clk, old_parent);
1307 clk_enable_unlock(flags);
1309 if (clk->prepare_count) {
1311 clk_disable(parent);
1312 __clk_unprepare(parent);
1317 __clk_set_parent_after(clk, parent, old_parent);
1323 * __clk_speculate_rates
1324 * @clk: first clk in the subtree
1325 * @parent_rate: the "future" rate of clk's parent
1327 * Walks the subtree of clks starting with clk, speculating rates as it
1328 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1330 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1331 * pre-rate change notifications and returns early if no clks in the
1332 * subtree have subscribed to the notifications. Note that if a clk does not
1333 * implement the .recalc_rate callback then it is assumed that the clock will
1334 * take on the rate of its parent.
1336 * Caller must hold prepare_lock.
1338 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1341 unsigned long new_rate;
1342 int ret = NOTIFY_DONE;
1344 new_rate = clk_recalc(clk, parent_rate);
1346 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1347 if (clk->notifier_count)
1348 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1350 if (ret & NOTIFY_STOP_MASK) {
1351 pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
1352 __func__, clk->name, ret);
1356 hlist_for_each_entry(child, &clk->children, child_node) {
1357 ret = __clk_speculate_rates(child, new_rate);
1358 if (ret & NOTIFY_STOP_MASK)
1366 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1367 struct clk *new_parent, u8 p_index)
1371 clk->new_rate = new_rate;
1372 clk->new_parent = new_parent;
1373 clk->new_parent_index = p_index;
1374 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1375 clk->new_child = NULL;
1376 if (new_parent && new_parent != clk->parent)
1377 new_parent->new_child = clk;
1379 hlist_for_each_entry(child, &clk->children, child_node) {
1380 child->new_rate = clk_recalc(child, new_rate);
1381 clk_calc_subtree(child, child->new_rate, NULL, 0);
1386 * calculate the new rates returning the topmost clock that has to be
1389 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1391 struct clk *top = clk;
1392 struct clk *old_parent, *parent;
1393 unsigned long best_parent_rate = 0;
1394 unsigned long new_rate;
1398 if (IS_ERR_OR_NULL(clk))
1401 /* save parent rate, if it exists */
1402 parent = old_parent = clk->parent;
1404 best_parent_rate = parent->rate;
1406 /* find the closest rate and parent clk/rate */
1407 if (clk->ops->determine_rate) {
1408 new_rate = clk->ops->determine_rate(clk->hw, rate,
1411 } else if (clk->ops->round_rate) {
1412 new_rate = clk->ops->round_rate(clk->hw, rate,
1414 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1415 /* pass-through clock without adjustable parent */
1416 clk->new_rate = clk->rate;
1419 /* pass-through clock with adjustable parent */
1420 top = clk_calc_new_rates(parent, rate);
1421 new_rate = parent->new_rate;
1425 /* some clocks must be gated to change parent */
1426 if (parent != old_parent &&
1427 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1428 pr_debug("%s: %s not gated but wants to reparent\n",
1429 __func__, clk->name);
1433 /* try finding the new parent index */
1435 p_index = clk_fetch_parent_index(clk, parent);
1437 pr_debug("%s: clk %s can not be parent of clk %s\n",
1438 __func__, parent->name, clk->name);
1443 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1444 best_parent_rate != parent->rate)
1445 top = clk_calc_new_rates(parent, best_parent_rate);
1448 clk_calc_subtree(clk, new_rate, parent, p_index);
1454 * Notify about rate changes in a subtree. Always walk down the whole tree
1455 * so that in case of an error we can walk down the whole tree again and
1458 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1460 struct clk *child, *tmp_clk, *fail_clk = NULL;
1461 int ret = NOTIFY_DONE;
1463 if (clk->rate == clk->new_rate)
1466 if (clk->notifier_count) {
1467 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1468 if (ret & NOTIFY_STOP_MASK)
1472 hlist_for_each_entry(child, &clk->children, child_node) {
1473 /* Skip children who will be reparented to another clock */
1474 if (child->new_parent && child->new_parent != clk)
1476 tmp_clk = clk_propagate_rate_change(child, event);
1481 /* handle the new child who might not be in clk->children yet */
1482 if (clk->new_child) {
1483 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1492 * walk down a subtree and set the new rates notifying the rate
1495 static void clk_change_rate(struct clk *clk)
1498 unsigned long old_rate;
1499 unsigned long best_parent_rate = 0;
1500 bool skip_set_rate = false;
1501 struct clk *old_parent;
1503 old_rate = clk->rate;
1505 if (clk->new_parent)
1506 best_parent_rate = clk->new_parent->rate;
1507 else if (clk->parent)
1508 best_parent_rate = clk->parent->rate;
1510 if (clk->new_parent && clk->new_parent != clk->parent) {
1511 old_parent = __clk_set_parent_before(clk, clk->new_parent);
1513 if (clk->ops->set_rate_and_parent) {
1514 skip_set_rate = true;
1515 clk->ops->set_rate_and_parent(clk->hw, clk->new_rate,
1517 clk->new_parent_index);
1518 } else if (clk->ops->set_parent) {
1519 clk->ops->set_parent(clk->hw, clk->new_parent_index);
1522 __clk_set_parent_after(clk, clk->new_parent, old_parent);
1525 if (!skip_set_rate && clk->ops->set_rate)
1526 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1528 clk->rate = clk_recalc(clk, best_parent_rate);
1530 if (clk->notifier_count && old_rate != clk->rate)
1531 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1533 hlist_for_each_entry(child, &clk->children, child_node) {
1534 /* Skip children who will be reparented to another clock */
1535 if (child->new_parent && child->new_parent != clk)
1537 clk_change_rate(child);
1540 /* handle the new child who might not be in clk->children yet */
1542 clk_change_rate(clk->new_child);
1546 * clk_set_rate - specify a new rate for clk
1547 * @clk: the clk whose rate is being changed
1548 * @rate: the new rate for clk
1550 * In the simplest case clk_set_rate will only adjust the rate of clk.
1552 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1553 * propagate up to clk's parent; whether or not this happens depends on the
1554 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1555 * after calling .round_rate then upstream parent propagation is ignored. If
1556 * *parent_rate comes back with a new rate for clk's parent then we propagate
1557 * up to clk's parent and set its rate. Upward propagation will continue
1558 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1559 * .round_rate stops requesting changes to clk's parent_rate.
1561 * Rate changes are accomplished via tree traversal that also recalculates the
1562 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1564 * Returns 0 on success, -EERROR otherwise.
1566 int clk_set_rate(struct clk *clk, unsigned long rate)
1568 struct clk *top, *fail_clk;
1574 /* prevent racing with updates to the clock topology */
1577 /* bail early if nothing to do */
1578 if (rate == clk_get_rate(clk))
1581 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1586 /* calculate new rates and get the topmost changed clock */
1587 top = clk_calc_new_rates(clk, rate);
1593 /* notify that we are about to change rates */
1594 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1596 pr_debug("%s: failed to set %s rate\n", __func__,
1598 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1603 /* change the rates */
1604 clk_change_rate(top);
1607 clk_prepare_unlock();
1611 EXPORT_SYMBOL_GPL(clk_set_rate);
1614 * clk_get_parent - return the parent of a clk
1615 * @clk: the clk whose parent gets returned
1617 * Simply returns clk->parent. Returns NULL if clk is NULL.
1619 struct clk *clk_get_parent(struct clk *clk)
1624 parent = __clk_get_parent(clk);
1625 clk_prepare_unlock();
1629 EXPORT_SYMBOL_GPL(clk_get_parent);
1632 * .get_parent is mandatory for clocks with multiple possible parents. It is
1633 * optional for single-parent clocks. Always call .get_parent if it is
1634 * available and WARN if it is missing for multi-parent clocks.
1636 * For single-parent clocks without .get_parent, first check to see if the
1637 * .parents array exists, and if so use it to avoid an expensive tree
1638 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1640 static struct clk *__clk_init_parent(struct clk *clk)
1642 struct clk *ret = NULL;
1645 /* handle the trivial cases */
1647 if (!clk->num_parents)
1650 if (clk->num_parents == 1) {
1651 if (IS_ERR_OR_NULL(clk->parent))
1652 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1657 if (!clk->ops->get_parent) {
1658 WARN(!clk->ops->get_parent,
1659 "%s: multi-parent clocks must implement .get_parent\n",
1665 * Do our best to cache parent clocks in clk->parents. This prevents
1666 * unnecessary and expensive calls to __clk_lookup. We don't set
1667 * clk->parent here; that is done by the calling function
1670 index = clk->ops->get_parent(clk->hw);
1674 kcalloc(clk->num_parents, sizeof(struct clk *),
1677 ret = clk_get_parent_by_index(clk, index);
1683 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1685 clk_reparent(clk, new_parent);
1686 clk_debug_reparent(clk, new_parent);
1687 __clk_recalc_accuracies(clk);
1688 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1692 * clk_set_parent - switch the parent of a mux clk
1693 * @clk: the mux clk whose input we are switching
1694 * @parent: the new input to clk
1696 * Re-parent clk to use parent as its new input source. If clk is in
1697 * prepared state, the clk will get enabled for the duration of this call. If
1698 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1699 * that, the reparenting is glitchy in hardware, etc), use the
1700 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1702 * After successfully changing clk's parent clk_set_parent will update the
1703 * clk topology, sysfs topology and propagate rate recalculation via
1704 * __clk_recalc_rates.
1706 * Returns 0 on success, -EERROR otherwise.
1708 int clk_set_parent(struct clk *clk, struct clk *parent)
1712 unsigned long p_rate = 0;
1717 /* verify ops for for multi-parent clks */
1718 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1721 /* prevent racing with updates to the clock topology */
1724 if (clk->parent == parent)
1727 /* check that we are allowed to re-parent if the clock is in use */
1728 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1733 /* try finding the new parent index */
1735 p_index = clk_fetch_parent_index(clk, parent);
1736 p_rate = parent->rate;
1738 pr_debug("%s: clk %s can not be parent of clk %s\n",
1739 __func__, parent->name, clk->name);
1745 /* propagate PRE_RATE_CHANGE notifications */
1746 ret = __clk_speculate_rates(clk, p_rate);
1748 /* abort if a driver objects */
1749 if (ret & NOTIFY_STOP_MASK)
1752 /* do the re-parent */
1753 ret = __clk_set_parent(clk, parent, p_index);
1755 /* propagate rate an accuracy recalculation accordingly */
1757 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1759 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1760 __clk_recalc_accuracies(clk);
1764 clk_prepare_unlock();
1768 EXPORT_SYMBOL_GPL(clk_set_parent);
1771 * __clk_init - initialize the data structures in a struct clk
1772 * @dev: device initializing this clk, placeholder for now
1773 * @clk: clk being initialized
1775 * Initializes the lists in struct clk, queries the hardware for the
1776 * parent and rate and sets them both.
1778 int __clk_init(struct device *dev, struct clk *clk)
1782 struct hlist_node *tmp2;
1789 /* check to see if a clock with this name is already registered */
1790 if (__clk_lookup(clk->name)) {
1791 pr_debug("%s: clk %s already initialized\n",
1792 __func__, clk->name);
1797 /* check that clk_ops are sane. See Documentation/clk.txt */
1798 if (clk->ops->set_rate &&
1799 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1800 clk->ops->recalc_rate)) {
1801 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1802 __func__, clk->name);
1807 if (clk->ops->set_parent && !clk->ops->get_parent) {
1808 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1809 __func__, clk->name);
1814 if (clk->ops->set_rate_and_parent &&
1815 !(clk->ops->set_parent && clk->ops->set_rate)) {
1816 pr_warn("%s: %s must implement .set_parent & .set_rate\n",
1817 __func__, clk->name);
1822 /* throw a WARN if any entries in parent_names are NULL */
1823 for (i = 0; i < clk->num_parents; i++)
1824 WARN(!clk->parent_names[i],
1825 "%s: invalid NULL in %s's .parent_names\n",
1826 __func__, clk->name);
1829 * Allocate an array of struct clk *'s to avoid unnecessary string
1830 * look-ups of clk's possible parents. This can fail for clocks passed
1831 * in to clk_init during early boot; thus any access to clk->parents[]
1832 * must always check for a NULL pointer and try to populate it if
1835 * If clk->parents is not NULL we skip this entire block. This allows
1836 * for clock drivers to statically initialize clk->parents.
1838 if (clk->num_parents > 1 && !clk->parents) {
1839 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
1842 * __clk_lookup returns NULL for parents that have not been
1843 * clk_init'd; thus any access to clk->parents[] must check
1844 * for a NULL pointer. We can always perform lazy lookups for
1845 * missing parents later on.
1848 for (i = 0; i < clk->num_parents; i++)
1850 __clk_lookup(clk->parent_names[i]);
1853 clk->parent = __clk_init_parent(clk);
1856 * Populate clk->parent if parent has already been __clk_init'd. If
1857 * parent has not yet been __clk_init'd then place clk in the orphan
1858 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1861 * Every time a new clk is clk_init'd then we walk the list of orphan
1862 * clocks and re-parent any that are children of the clock currently
1866 hlist_add_head(&clk->child_node,
1867 &clk->parent->children);
1868 else if (clk->flags & CLK_IS_ROOT)
1869 hlist_add_head(&clk->child_node, &clk_root_list);
1871 hlist_add_head(&clk->child_node, &clk_orphan_list);
1874 * Set clk's accuracy. The preferred method is to use
1875 * .recalc_accuracy. For simple clocks and lazy developers the default
1876 * fallback is to use the parent's accuracy. If a clock doesn't have a
1877 * parent (or is orphaned) then accuracy is set to zero (perfect
1880 if (clk->ops->recalc_accuracy)
1881 clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
1882 __clk_get_accuracy(clk->parent));
1883 else if (clk->parent)
1884 clk->accuracy = clk->parent->accuracy;
1889 * Set clk's rate. The preferred method is to use .recalc_rate. For
1890 * simple clocks and lazy developers the default fallback is to use the
1891 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1892 * then rate is set to zero.
1894 if (clk->ops->recalc_rate)
1895 clk->rate = clk->ops->recalc_rate(clk->hw,
1896 __clk_get_rate(clk->parent));
1897 else if (clk->parent)
1898 clk->rate = clk->parent->rate;
1902 clk_debug_register(clk);
1904 * walk the list of orphan clocks and reparent any that are children of
1907 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1908 if (orphan->num_parents && orphan->ops->get_parent) {
1909 i = orphan->ops->get_parent(orphan->hw);
1910 if (!strcmp(clk->name, orphan->parent_names[i]))
1911 __clk_reparent(orphan, clk);
1915 for (i = 0; i < orphan->num_parents; i++)
1916 if (!strcmp(clk->name, orphan->parent_names[i])) {
1917 __clk_reparent(orphan, clk);
1923 * optional platform-specific magic
1925 * The .init callback is not used by any of the basic clock types, but
1926 * exists for weird hardware that must perform initialization magic.
1927 * Please consider other ways of solving initialization problems before
1928 * using this callback, as its use is discouraged.
1931 clk->ops->init(clk->hw);
1933 kref_init(&clk->ref);
1935 clk_prepare_unlock();
1941 * __clk_register - register a clock and return a cookie.
1943 * Same as clk_register, except that the .clk field inside hw shall point to a
1944 * preallocated (generally statically allocated) struct clk. None of the fields
1945 * of the struct clk need to be initialized.
1947 * The data pointed to by .init and .clk field shall NOT be marked as init
1950 * __clk_register is only exposed via clk-private.h and is intended for use with
1951 * very large numbers of clocks that need to be statically initialized. It is
1952 * a layering violation to include clk-private.h from any code which implements
1953 * a clock's .ops; as such any statically initialized clock data MUST be in a
1954 * separate C file from the logic that implements its operations. Returns 0
1955 * on success, otherwise an error code.
1957 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1963 clk->name = hw->init->name;
1964 clk->ops = hw->init->ops;
1966 clk->flags = hw->init->flags;
1967 clk->parent_names = hw->init->parent_names;
1968 clk->num_parents = hw->init->num_parents;
1969 if (dev && dev->driver)
1970 clk->owner = dev->driver->owner;
1974 ret = __clk_init(dev, clk);
1976 return ERR_PTR(ret);
1980 EXPORT_SYMBOL_GPL(__clk_register);
1983 * clk_register - allocate a new clock, register it and return an opaque cookie
1984 * @dev: device that is registering this clock
1985 * @hw: link to hardware-specific clock data
1987 * clk_register is the primary interface for populating the clock tree with new
1988 * clock nodes. It returns a pointer to the newly allocated struct clk which
1989 * cannot be dereferenced by driver code but may be used in conjuction with the
1990 * rest of the clock API. In the event of an error clk_register will return an
1991 * error code; drivers must test for an error code after calling clk_register.
1993 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1998 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
2000 pr_err("%s: could not allocate clk\n", __func__);
2005 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
2007 pr_err("%s: could not allocate clk->name\n", __func__);
2011 clk->ops = hw->init->ops;
2012 if (dev && dev->driver)
2013 clk->owner = dev->driver->owner;
2015 clk->flags = hw->init->flags;
2016 clk->num_parents = hw->init->num_parents;
2019 /* allocate local copy in case parent_names is __initdata */
2020 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
2023 if (!clk->parent_names) {
2024 pr_err("%s: could not allocate clk->parent_names\n", __func__);
2026 goto fail_parent_names;
2030 /* copy each string name in case parent_names is __initdata */
2031 for (i = 0; i < clk->num_parents; i++) {
2032 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
2034 if (!clk->parent_names[i]) {
2035 pr_err("%s: could not copy parent_names\n", __func__);
2037 goto fail_parent_names_copy;
2041 ret = __clk_init(dev, clk);
2045 fail_parent_names_copy:
2047 kfree(clk->parent_names[i]);
2048 kfree(clk->parent_names);
2054 return ERR_PTR(ret);
2056 EXPORT_SYMBOL_GPL(clk_register);
2059 * Free memory allocated for a clock.
2060 * Caller must hold prepare_lock.
2062 static void __clk_release(struct kref *ref)
2064 struct clk *clk = container_of(ref, struct clk, ref);
2065 int i = clk->num_parents;
2067 kfree(clk->parents);
2069 kfree(clk->parent_names[i]);
2071 kfree(clk->parent_names);
2077 * Empty clk_ops for unregistered clocks. These are used temporarily
2078 * after clk_unregister() was called on a clock and until last clock
2079 * consumer calls clk_put() and the struct clk object is freed.
2081 static int clk_nodrv_prepare_enable(struct clk_hw *hw)
2086 static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
2091 static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
2092 unsigned long parent_rate)
2097 static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
2102 static const struct clk_ops clk_nodrv_ops = {
2103 .enable = clk_nodrv_prepare_enable,
2104 .disable = clk_nodrv_disable_unprepare,
2105 .prepare = clk_nodrv_prepare_enable,
2106 .unprepare = clk_nodrv_disable_unprepare,
2107 .set_rate = clk_nodrv_set_rate,
2108 .set_parent = clk_nodrv_set_parent,
2112 * clk_unregister - unregister a currently registered clock
2113 * @clk: clock to unregister
2115 void clk_unregister(struct clk *clk)
2117 unsigned long flags;
2119 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2124 if (clk->ops == &clk_nodrv_ops) {
2125 pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
2129 * Assign empty clock ops for consumers that might still hold
2130 * a reference to this clock.
2132 flags = clk_enable_lock();
2133 clk->ops = &clk_nodrv_ops;
2134 clk_enable_unlock(flags);
2136 if (!hlist_empty(&clk->children)) {
2138 struct hlist_node *t;
2140 /* Reparent all children to the orphan list. */
2141 hlist_for_each_entry_safe(child, t, &clk->children, child_node)
2142 clk_set_parent(child, NULL);
2145 clk_debug_unregister(clk);
2147 hlist_del_init(&clk->child_node);
2149 if (clk->prepare_count)
2150 pr_warn("%s: unregistering prepared clock: %s\n",
2151 __func__, clk->name);
2153 kref_put(&clk->ref, __clk_release);
2155 clk_prepare_unlock();
2157 EXPORT_SYMBOL_GPL(clk_unregister);
2159 static void devm_clk_release(struct device *dev, void *res)
2161 clk_unregister(*(struct clk **)res);
2165 * devm_clk_register - resource managed clk_register()
2166 * @dev: device that is registering this clock
2167 * @hw: link to hardware-specific clock data
2169 * Managed clk_register(). Clocks returned from this function are
2170 * automatically clk_unregister()ed on driver detach. See clk_register() for
2173 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
2178 clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
2180 return ERR_PTR(-ENOMEM);
2182 clk = clk_register(dev, hw);
2185 devres_add(dev, clkp);
2192 EXPORT_SYMBOL_GPL(devm_clk_register);
2194 static int devm_clk_match(struct device *dev, void *res, void *data)
2196 struct clk *c = res;
2203 * devm_clk_unregister - resource managed clk_unregister()
2204 * @clk: clock to unregister
2206 * Deallocate a clock allocated with devm_clk_register(). Normally
2207 * this function will not need to be called and the resource management
2208 * code will ensure that the resource is freed.
2210 void devm_clk_unregister(struct device *dev, struct clk *clk)
2212 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
2214 EXPORT_SYMBOL_GPL(devm_clk_unregister);
2219 int __clk_get(struct clk *clk)
2222 if (!try_module_get(clk->owner))
2225 kref_get(&clk->ref);
2230 void __clk_put(struct clk *clk)
2232 if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
2236 kref_put(&clk->ref, __clk_release);
2237 clk_prepare_unlock();
2239 module_put(clk->owner);
2242 /*** clk rate change notifiers ***/
2245 * clk_notifier_register - add a clk rate change notifier
2246 * @clk: struct clk * to watch
2247 * @nb: struct notifier_block * with callback info
2249 * Request notification when clk's rate changes. This uses an SRCU
2250 * notifier because we want it to block and notifier unregistrations are
2251 * uncommon. The callbacks associated with the notifier must not
2252 * re-enter into the clk framework by calling any top-level clk APIs;
2253 * this will cause a nested prepare_lock mutex.
2255 * In all notification cases cases (pre, post and abort rate change) the
2256 * original clock rate is passed to the callback via struct
2257 * clk_notifier_data.old_rate and the new frequency is passed via struct
2258 * clk_notifier_data.new_rate.
2260 * clk_notifier_register() must be called from non-atomic context.
2261 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2262 * allocation failure; otherwise, passes along the return value of
2263 * srcu_notifier_chain_register().
2265 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2267 struct clk_notifier *cn;
2275 /* search the list of notifiers for this clk */
2276 list_for_each_entry(cn, &clk_notifier_list, node)
2280 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2281 if (cn->clk != clk) {
2282 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2287 srcu_init_notifier_head(&cn->notifier_head);
2289 list_add(&cn->node, &clk_notifier_list);
2292 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2294 clk->notifier_count++;
2297 clk_prepare_unlock();
2301 EXPORT_SYMBOL_GPL(clk_notifier_register);
2304 * clk_notifier_unregister - remove a clk rate change notifier
2305 * @clk: struct clk *
2306 * @nb: struct notifier_block * with callback info
2308 * Request no further notification for changes to 'clk' and frees memory
2309 * allocated in clk_notifier_register.
2311 * Returns -EINVAL if called with null arguments; otherwise, passes
2312 * along the return value of srcu_notifier_chain_unregister().
2314 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2316 struct clk_notifier *cn = NULL;
2324 list_for_each_entry(cn, &clk_notifier_list, node)
2328 if (cn->clk == clk) {
2329 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2331 clk->notifier_count--;
2333 /* XXX the notifier code should handle this better */
2334 if (!cn->notifier_head.head) {
2335 srcu_cleanup_notifier_head(&cn->notifier_head);
2336 list_del(&cn->node);
2344 clk_prepare_unlock();
2348 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2352 * struct of_clk_provider - Clock provider registration structure
2353 * @link: Entry in global list of clock providers
2354 * @node: Pointer to device tree node of clock provider
2355 * @get: Get clock callback. Returns NULL or a struct clk for the
2356 * given clock specifier
2357 * @data: context pointer to be passed into @get callback
2359 struct of_clk_provider {
2360 struct list_head link;
2362 struct device_node *node;
2363 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2367 static const struct of_device_id __clk_of_table_sentinel
2368 __used __section(__clk_of_table_end);
2370 static LIST_HEAD(of_clk_providers);
2371 static DEFINE_MUTEX(of_clk_mutex);
2373 /* of_clk_provider list locking helpers */
2374 void of_clk_lock(void)
2376 mutex_lock(&of_clk_mutex);
2379 void of_clk_unlock(void)
2381 mutex_unlock(&of_clk_mutex);
2384 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2389 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2391 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2393 struct clk_onecell_data *clk_data = data;
2394 unsigned int idx = clkspec->args[0];
2396 if (idx >= clk_data->clk_num) {
2397 pr_err("%s: invalid clock index %d\n", __func__, idx);
2398 return ERR_PTR(-EINVAL);
2401 return clk_data->clks[idx];
2403 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2406 * of_clk_add_provider() - Register a clock provider for a node
2407 * @np: Device node pointer associated with clock provider
2408 * @clk_src_get: callback for decoding clock
2409 * @data: context pointer for @clk_src_get callback.
2411 int of_clk_add_provider(struct device_node *np,
2412 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2416 struct of_clk_provider *cp;
2418 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2422 cp->node = of_node_get(np);
2424 cp->get = clk_src_get;
2426 mutex_lock(&of_clk_mutex);
2427 list_add(&cp->link, &of_clk_providers);
2428 mutex_unlock(&of_clk_mutex);
2429 pr_debug("Added clock from %s\n", np->full_name);
2433 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2436 * of_clk_del_provider() - Remove a previously registered clock provider
2437 * @np: Device node pointer associated with clock provider
2439 void of_clk_del_provider(struct device_node *np)
2441 struct of_clk_provider *cp;
2443 mutex_lock(&of_clk_mutex);
2444 list_for_each_entry(cp, &of_clk_providers, link) {
2445 if (cp->node == np) {
2446 list_del(&cp->link);
2447 of_node_put(cp->node);
2452 mutex_unlock(&of_clk_mutex);
2454 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2456 struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec)
2458 struct of_clk_provider *provider;
2459 struct clk *clk = ERR_PTR(-EPROBE_DEFER);
2461 /* Check if we have such a provider in our array */
2462 list_for_each_entry(provider, &of_clk_providers, link) {
2463 if (provider->node == clkspec->np)
2464 clk = provider->get(clkspec, provider->data);
2472 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2476 mutex_lock(&of_clk_mutex);
2477 clk = __of_clk_get_from_provider(clkspec);
2478 mutex_unlock(&of_clk_mutex);
2483 int of_clk_get_parent_count(struct device_node *np)
2485 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2487 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2489 const char *of_clk_get_parent_name(struct device_node *np, int index)
2491 struct of_phandle_args clkspec;
2492 struct property *prop;
2493 const char *clk_name;
2502 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2507 index = clkspec.args_count ? clkspec.args[0] : 0;
2510 /* if there is an indices property, use it to transfer the index
2511 * specified into an array offset for the clock-output-names property.
2513 of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
2521 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2524 clk_name = clkspec.np->name;
2526 of_node_put(clkspec.np);
2529 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2531 struct clock_provider {
2532 of_clk_init_cb_t clk_init_cb;
2533 struct device_node *np;
2534 struct list_head node;
2537 static LIST_HEAD(clk_provider_list);
2540 * This function looks for a parent clock. If there is one, then it
2541 * checks that the provider for this parent clock was initialized, in
2542 * this case the parent clock will be ready.
2544 static int parent_ready(struct device_node *np)
2549 struct clk *clk = of_clk_get(np, i);
2551 /* this parent is ready we can check the next one */
2558 /* at least one parent is not ready, we exit now */
2559 if (PTR_ERR(clk) == -EPROBE_DEFER)
2563 * Here we make assumption that the device tree is
2564 * written correctly. So an error means that there is
2565 * no more parent. As we didn't exit yet, then the
2566 * previous parent are ready. If there is no clock
2567 * parent, no need to wait for them, then we can
2568 * consider their absence as being ready
2575 * of_clk_init() - Scan and init clock providers from the DT
2576 * @matches: array of compatible values and init functions for providers.
2578 * This function scans the device tree for matching clock providers
2579 * and calls their initialization functions. It also does it by trying
2580 * to follow the dependencies.
2582 void __init of_clk_init(const struct of_device_id *matches)
2584 const struct of_device_id *match;
2585 struct device_node *np;
2586 struct clock_provider *clk_provider, *next;
2591 matches = &__clk_of_table;
2593 /* First prepare the list of the clocks providers */
2594 for_each_matching_node_and_match(np, matches, &match) {
2595 struct clock_provider *parent =
2596 kzalloc(sizeof(struct clock_provider), GFP_KERNEL);
2598 parent->clk_init_cb = match->data;
2600 list_add_tail(&parent->node, &clk_provider_list);
2603 while (!list_empty(&clk_provider_list)) {
2604 is_init_done = false;
2605 list_for_each_entry_safe(clk_provider, next,
2606 &clk_provider_list, node) {
2607 if (force || parent_ready(clk_provider->np)) {
2608 clk_provider->clk_init_cb(clk_provider->np);
2609 list_del(&clk_provider->node);
2610 kfree(clk_provider);
2611 is_init_done = true;
2616 * We didn't manage to initialize any of the
2617 * remaining providers during the last loop, so now we
2618 * initialize all the remaining ones unconditionally
2619 * in case the clock parent was not mandatory