2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Standard functionality for the common clock API. See Documentation/clk.txt
12 #include <linux/clk-private.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock.h>
16 #include <linux/err.h>
17 #include <linux/list.h>
18 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
24 static DEFINE_SPINLOCK(enable_lock);
25 static DEFINE_MUTEX(prepare_lock);
27 static struct task_struct *prepare_owner;
28 static struct task_struct *enable_owner;
30 static int prepare_refcnt;
31 static int enable_refcnt;
33 static HLIST_HEAD(clk_root_list);
34 static HLIST_HEAD(clk_orphan_list);
35 static LIST_HEAD(clk_notifier_list);
38 static void clk_prepare_lock(void)
40 if (!mutex_trylock(&prepare_lock)) {
41 if (prepare_owner == current) {
45 mutex_lock(&prepare_lock);
47 WARN_ON_ONCE(prepare_owner != NULL);
48 WARN_ON_ONCE(prepare_refcnt != 0);
49 prepare_owner = current;
53 static void clk_prepare_unlock(void)
55 WARN_ON_ONCE(prepare_owner != current);
56 WARN_ON_ONCE(prepare_refcnt == 0);
61 mutex_unlock(&prepare_lock);
64 static unsigned long clk_enable_lock(void)
68 if (!spin_trylock_irqsave(&enable_lock, flags)) {
69 if (enable_owner == current) {
73 spin_lock_irqsave(&enable_lock, flags);
75 WARN_ON_ONCE(enable_owner != NULL);
76 WARN_ON_ONCE(enable_refcnt != 0);
77 enable_owner = current;
82 static void clk_enable_unlock(unsigned long flags)
84 WARN_ON_ONCE(enable_owner != current);
85 WARN_ON_ONCE(enable_refcnt == 0);
90 spin_unlock_irqrestore(&enable_lock, flags);
93 /*** debugfs support ***/
95 #ifdef CONFIG_COMMON_CLK_DEBUG
96 #include <linux/debugfs.h>
98 static struct dentry *rootdir;
99 static struct dentry *orphandir;
100 static int inited = 0;
102 static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
107 seq_printf(s, "%*s%-*s %-11d %-12d %-10lu",
109 30 - level * 3, c->name,
110 c->enable_count, c->prepare_count, clk_get_rate(c));
114 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
122 clk_summary_show_one(s, c, level);
124 hlist_for_each_entry(child, &c->children, child_node)
125 clk_summary_show_subtree(s, child, level + 1);
128 static int clk_summary_show(struct seq_file *s, void *data)
132 seq_printf(s, " clock enable_cnt prepare_cnt rate\n");
133 seq_printf(s, "---------------------------------------------------------------------\n");
137 hlist_for_each_entry(c, &clk_root_list, child_node)
138 clk_summary_show_subtree(s, c, 0);
140 hlist_for_each_entry(c, &clk_orphan_list, child_node)
141 clk_summary_show_subtree(s, c, 0);
143 clk_prepare_unlock();
149 static int clk_summary_open(struct inode *inode, struct file *file)
151 return single_open(file, clk_summary_show, inode->i_private);
154 static const struct file_operations clk_summary_fops = {
155 .open = clk_summary_open,
158 .release = single_release,
161 static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
166 seq_printf(s, "\"%s\": { ", c->name);
167 seq_printf(s, "\"enable_count\": %d,", c->enable_count);
168 seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
169 seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
172 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
179 clk_dump_one(s, c, level);
181 hlist_for_each_entry(child, &c->children, child_node) {
183 clk_dump_subtree(s, child, level + 1);
189 static int clk_dump(struct seq_file *s, void *data)
192 bool first_node = true;
198 hlist_for_each_entry(c, &clk_root_list, child_node) {
202 clk_dump_subtree(s, c, 0);
205 hlist_for_each_entry(c, &clk_orphan_list, child_node) {
207 clk_dump_subtree(s, c, 0);
210 clk_prepare_unlock();
217 static int clk_dump_open(struct inode *inode, struct file *file)
219 return single_open(file, clk_dump, inode->i_private);
222 static const struct file_operations clk_dump_fops = {
223 .open = clk_dump_open,
226 .release = single_release,
229 /* caller must hold prepare_lock */
230 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
235 if (!clk || !pdentry) {
240 d = debugfs_create_dir(clk->name, pdentry);
246 d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
251 d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
256 d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
257 (u32 *)&clk->prepare_count);
261 d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
262 (u32 *)&clk->enable_count);
266 d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
267 (u32 *)&clk->notifier_count);
275 debugfs_remove_recursive(clk->dentry);
281 /* caller must hold prepare_lock */
282 static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
287 if (!clk || !pdentry)
290 ret = clk_debug_create_one(clk, pdentry);
295 hlist_for_each_entry(child, &clk->children, child_node)
296 clk_debug_create_subtree(child, clk->dentry);
304 * clk_debug_register - add a clk node to the debugfs clk tree
305 * @clk: the clk being added to the debugfs clk tree
307 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
308 * initialized. Otherwise it bails out early since the debugfs clk tree
309 * will be created lazily by clk_debug_init as part of a late_initcall.
311 * Caller must hold prepare_lock. Only clk_init calls this function (so
312 * far) so this is taken care.
314 static int clk_debug_register(struct clk *clk)
317 struct dentry *pdentry;
323 parent = clk->parent;
326 * Check to see if a clk is a root clk. Also check that it is
327 * safe to add this clk to debugfs
330 if (clk->flags & CLK_IS_ROOT)
336 pdentry = parent->dentry;
340 ret = clk_debug_create_subtree(clk, pdentry);
347 * clk_debug_reparent - reparent clk node in the debugfs clk tree
348 * @clk: the clk being reparented
349 * @new_parent: the new clk parent, may be NULL
351 * Rename clk entry in the debugfs clk tree if debugfs has been
352 * initialized. Otherwise it bails out early since the debugfs clk tree
353 * will be created lazily by clk_debug_init as part of a late_initcall.
355 * Caller must hold prepare_lock.
357 static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
360 struct dentry *new_parent_d;
366 new_parent_d = new_parent->dentry;
368 new_parent_d = orphandir;
370 d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
371 new_parent_d, clk->name);
375 pr_debug("%s: failed to rename debugfs entry for %s\n",
376 __func__, clk->name);
380 * clk_debug_init - lazily create the debugfs clk tree visualization
382 * clks are often initialized very early during boot before memory can
383 * be dynamically allocated and well before debugfs is setup.
384 * clk_debug_init walks the clk tree hierarchy while holding
385 * prepare_lock and creates the topology as part of a late_initcall,
386 * thus insuring that clks initialized very early will still be
387 * represented in the debugfs clk tree. This function should only be
388 * called once at boot-time, and all other clks added dynamically will
389 * be done so with clk_debug_register.
391 static int __init clk_debug_init(void)
396 rootdir = debugfs_create_dir("clk", NULL);
401 d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
406 d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
411 orphandir = debugfs_create_dir("orphans", rootdir);
418 hlist_for_each_entry(clk, &clk_root_list, child_node)
419 clk_debug_create_subtree(clk, rootdir);
421 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
422 clk_debug_create_subtree(clk, orphandir);
426 clk_prepare_unlock();
430 late_initcall(clk_debug_init);
432 static inline int clk_debug_register(struct clk *clk) { return 0; }
433 static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
438 /* caller must hold prepare_lock */
439 static void clk_unprepare_unused_subtree(struct clk *clk)
446 hlist_for_each_entry(child, &clk->children, child_node)
447 clk_unprepare_unused_subtree(child);
449 if (clk->prepare_count)
452 if (clk->flags & CLK_IGNORE_UNUSED)
455 if (__clk_is_prepared(clk)) {
456 if (clk->ops->unprepare_unused)
457 clk->ops->unprepare_unused(clk->hw);
458 else if (clk->ops->unprepare)
459 clk->ops->unprepare(clk->hw);
463 /* caller must hold prepare_lock */
464 static void clk_disable_unused_subtree(struct clk *clk)
472 hlist_for_each_entry(child, &clk->children, child_node)
473 clk_disable_unused_subtree(child);
475 flags = clk_enable_lock();
477 if (clk->enable_count)
480 if (clk->flags & CLK_IGNORE_UNUSED)
484 * some gate clocks have special needs during the disable-unused
485 * sequence. call .disable_unused if available, otherwise fall
488 if (__clk_is_enabled(clk)) {
489 if (clk->ops->disable_unused)
490 clk->ops->disable_unused(clk->hw);
491 else if (clk->ops->disable)
492 clk->ops->disable(clk->hw);
496 clk_enable_unlock(flags);
502 static bool clk_ignore_unused;
503 static int __init clk_ignore_unused_setup(char *__unused)
505 clk_ignore_unused = true;
508 __setup("clk_ignore_unused", clk_ignore_unused_setup);
510 static int clk_disable_unused(void)
514 if (clk_ignore_unused) {
515 pr_warn("clk: Not disabling unused clocks\n");
521 hlist_for_each_entry(clk, &clk_root_list, child_node)
522 clk_disable_unused_subtree(clk);
524 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
525 clk_disable_unused_subtree(clk);
527 hlist_for_each_entry(clk, &clk_root_list, child_node)
528 clk_unprepare_unused_subtree(clk);
530 hlist_for_each_entry(clk, &clk_orphan_list, child_node)
531 clk_unprepare_unused_subtree(clk);
533 clk_prepare_unlock();
537 late_initcall_sync(clk_disable_unused);
539 /*** helper functions ***/
541 const char *__clk_get_name(struct clk *clk)
543 return !clk ? NULL : clk->name;
545 EXPORT_SYMBOL_GPL(__clk_get_name);
547 struct clk_hw *__clk_get_hw(struct clk *clk)
549 return !clk ? NULL : clk->hw;
552 u8 __clk_get_num_parents(struct clk *clk)
554 return !clk ? 0 : clk->num_parents;
557 struct clk *__clk_get_parent(struct clk *clk)
559 return !clk ? NULL : clk->parent;
562 struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
564 if (!clk || index >= clk->num_parents)
566 else if (!clk->parents)
567 return __clk_lookup(clk->parent_names[index]);
568 else if (!clk->parents[index])
569 return clk->parents[index] =
570 __clk_lookup(clk->parent_names[index]);
572 return clk->parents[index];
575 unsigned int __clk_get_enable_count(struct clk *clk)
577 return !clk ? 0 : clk->enable_count;
580 unsigned int __clk_get_prepare_count(struct clk *clk)
582 return !clk ? 0 : clk->prepare_count;
585 unsigned long __clk_get_rate(struct clk *clk)
596 if (clk->flags & CLK_IS_ROOT)
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);
654 static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
659 if (!strcmp(clk->name, name))
662 hlist_for_each_entry(child, &clk->children, child_node) {
663 ret = __clk_lookup_subtree(name, child);
671 struct clk *__clk_lookup(const char *name)
673 struct clk *root_clk;
679 /* search the 'proper' clk tree first */
680 hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
681 ret = __clk_lookup_subtree(name, root_clk);
686 /* if not found, then search the orphan tree */
687 hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
688 ret = __clk_lookup_subtree(name, root_clk);
697 * Helper for finding best parent to provide a given frequency. This can be used
698 * directly as a determine_rate callback (e.g. for a mux), or from a more
699 * complex clock that may combine a mux with other operations.
701 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
702 unsigned long *best_parent_rate,
703 struct clk **best_parent_p)
705 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
707 unsigned long parent_rate, best = 0;
709 /* if NO_REPARENT flag set, pass through to current parent */
710 if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
711 parent = clk->parent;
712 if (clk->flags & CLK_SET_RATE_PARENT)
713 best = __clk_round_rate(parent, rate);
715 best = __clk_get_rate(parent);
717 best = __clk_get_rate(clk);
721 /* find the parent that can provide the fastest rate <= rate */
722 num_parents = clk->num_parents;
723 for (i = 0; i < num_parents; i++) {
724 parent = clk_get_parent_by_index(clk, i);
727 if (clk->flags & CLK_SET_RATE_PARENT)
728 parent_rate = __clk_round_rate(parent, rate);
730 parent_rate = __clk_get_rate(parent);
731 if (parent_rate <= rate && parent_rate > best) {
732 best_parent = parent;
739 *best_parent_p = best_parent;
740 *best_parent_rate = best;
747 void __clk_unprepare(struct clk *clk)
752 if (WARN_ON(clk->prepare_count == 0))
755 if (--clk->prepare_count > 0)
758 WARN_ON(clk->enable_count > 0);
760 if (clk->ops->unprepare)
761 clk->ops->unprepare(clk->hw);
763 __clk_unprepare(clk->parent);
767 * clk_unprepare - undo preparation of a clock source
768 * @clk: the clk being unprepared
770 * clk_unprepare may sleep, which differentiates it from clk_disable. In a
771 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
772 * if the operation may sleep. One example is a clk which is accessed over
773 * I2c. In the complex case a clk gate operation may require a fast and a slow
774 * part. It is this reason that clk_unprepare and clk_disable are not mutually
775 * exclusive. In fact clk_disable must be called before clk_unprepare.
777 void clk_unprepare(struct clk *clk)
780 __clk_unprepare(clk);
781 clk_prepare_unlock();
783 EXPORT_SYMBOL_GPL(clk_unprepare);
785 int __clk_prepare(struct clk *clk)
792 if (clk->prepare_count == 0) {
793 ret = __clk_prepare(clk->parent);
797 if (clk->ops->prepare) {
798 ret = clk->ops->prepare(clk->hw);
800 __clk_unprepare(clk->parent);
806 clk->prepare_count++;
812 * clk_prepare - prepare a clock source
813 * @clk: the clk being prepared
815 * clk_prepare may sleep, which differentiates it from clk_enable. In a simple
816 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
817 * operation may sleep. One example is a clk which is accessed over I2c. In
818 * the complex case a clk ungate operation may require a fast and a slow part.
819 * It is this reason that clk_prepare and clk_enable are not mutually
820 * exclusive. In fact clk_prepare must be called before clk_enable.
821 * Returns 0 on success, -EERROR otherwise.
823 int clk_prepare(struct clk *clk)
828 ret = __clk_prepare(clk);
829 clk_prepare_unlock();
833 EXPORT_SYMBOL_GPL(clk_prepare);
835 static void __clk_disable(struct clk *clk)
840 if (WARN_ON(IS_ERR(clk)))
843 if (WARN_ON(clk->enable_count == 0))
846 if (--clk->enable_count > 0)
849 if (clk->ops->disable)
850 clk->ops->disable(clk->hw);
852 __clk_disable(clk->parent);
856 * clk_disable - gate a clock
857 * @clk: the clk being gated
859 * clk_disable must not sleep, which differentiates it from clk_unprepare. In
860 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
861 * clk if the operation is fast and will never sleep. One example is a
862 * SoC-internal clk which is controlled via simple register writes. In the
863 * complex case a clk gate operation may require a fast and a slow part. It is
864 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
865 * In fact clk_disable must be called before clk_unprepare.
867 void clk_disable(struct clk *clk)
871 flags = clk_enable_lock();
873 clk_enable_unlock(flags);
875 EXPORT_SYMBOL_GPL(clk_disable);
877 static int __clk_enable(struct clk *clk)
884 if (WARN_ON(clk->prepare_count == 0))
887 if (clk->enable_count == 0) {
888 ret = __clk_enable(clk->parent);
893 if (clk->ops->enable) {
894 ret = clk->ops->enable(clk->hw);
896 __clk_disable(clk->parent);
907 * clk_enable - ungate a clock
908 * @clk: the clk being ungated
910 * clk_enable must not sleep, which differentiates it from clk_prepare. In a
911 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
912 * if the operation will never sleep. One example is a SoC-internal clk which
913 * is controlled via simple register writes. In the complex case a clk ungate
914 * operation may require a fast and a slow part. It is this reason that
915 * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
916 * must be called before clk_enable. Returns 0 on success, -EERROR
919 int clk_enable(struct clk *clk)
924 flags = clk_enable_lock();
925 ret = __clk_enable(clk);
926 clk_enable_unlock(flags);
930 EXPORT_SYMBOL_GPL(clk_enable);
933 * __clk_round_rate - round the given rate for a clk
934 * @clk: round the rate of this clock
935 * @rate: the rate which is to be rounded
937 * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
939 unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
941 unsigned long parent_rate = 0;
947 parent = clk->parent;
949 parent_rate = parent->rate;
951 if (clk->ops->determine_rate)
952 return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
954 else if (clk->ops->round_rate)
955 return clk->ops->round_rate(clk->hw, rate, &parent_rate);
956 else if (clk->flags & CLK_SET_RATE_PARENT)
957 return __clk_round_rate(clk->parent, rate);
963 * clk_round_rate - round the given rate for a clk
964 * @clk: the clk for which we are rounding a rate
965 * @rate: the rate which is to be rounded
967 * Takes in a rate as input and rounds it to a rate that the clk can actually
968 * use which is then returned. If clk doesn't support round_rate operation
969 * then the parent rate is returned.
971 long clk_round_rate(struct clk *clk, unsigned long rate)
976 ret = __clk_round_rate(clk, rate);
977 clk_prepare_unlock();
981 EXPORT_SYMBOL_GPL(clk_round_rate);
984 * __clk_notify - call clk notifier chain
985 * @clk: struct clk * that is changing rate
986 * @msg: clk notifier type (see include/linux/clk.h)
987 * @old_rate: old clk rate
988 * @new_rate: new clk rate
990 * Triggers a notifier call chain on the clk rate-change notification
991 * for 'clk'. Passes a pointer to the struct clk and the previous
992 * and current rates to the notifier callback. Intended to be called by
993 * internal clock code only. Returns NOTIFY_DONE from the last driver
994 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
995 * a driver returns that.
997 static int __clk_notify(struct clk *clk, unsigned long msg,
998 unsigned long old_rate, unsigned long new_rate)
1000 struct clk_notifier *cn;
1001 struct clk_notifier_data cnd;
1002 int ret = NOTIFY_DONE;
1005 cnd.old_rate = old_rate;
1006 cnd.new_rate = new_rate;
1008 list_for_each_entry(cn, &clk_notifier_list, node) {
1009 if (cn->clk == clk) {
1010 ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
1020 * __clk_recalc_rates
1021 * @clk: first clk in the subtree
1022 * @msg: notification type (see include/linux/clk.h)
1024 * Walks the subtree of clks starting with clk and recalculates rates as it
1025 * goes. Note that if a clk does not implement the .recalc_rate callback then
1026 * it is assumed that the clock will take on the rate of its parent.
1028 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
1031 * Caller must hold prepare_lock.
1033 static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
1035 unsigned long old_rate;
1036 unsigned long parent_rate = 0;
1039 old_rate = clk->rate;
1042 parent_rate = clk->parent->rate;
1044 if (clk->ops->recalc_rate)
1045 clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1047 clk->rate = parent_rate;
1050 * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
1051 * & ABORT_RATE_CHANGE notifiers
1053 if (clk->notifier_count && msg)
1054 __clk_notify(clk, msg, old_rate, clk->rate);
1056 hlist_for_each_entry(child, &clk->children, child_node)
1057 __clk_recalc_rates(child, msg);
1061 * clk_get_rate - return the rate of clk
1062 * @clk: the clk whose rate is being returned
1064 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
1065 * is set, which means a recalc_rate will be issued.
1066 * If clk is NULL then returns 0.
1068 unsigned long clk_get_rate(struct clk *clk)
1074 if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1075 __clk_recalc_rates(clk, 0);
1077 rate = __clk_get_rate(clk);
1078 clk_prepare_unlock();
1082 EXPORT_SYMBOL_GPL(clk_get_rate);
1084 static int clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1088 if (!clk->parents) {
1089 clk->parents = kcalloc(clk->num_parents,
1090 sizeof(struct clk *), GFP_KERNEL);
1096 * find index of new parent clock using cached parent ptrs,
1097 * or if not yet cached, use string name comparison and cache
1098 * them now to avoid future calls to __clk_lookup.
1100 for (i = 0; i < clk->num_parents; i++) {
1101 if (clk->parents[i] == parent)
1104 if (clk->parents[i])
1107 if (!strcmp(clk->parent_names[i], parent->name)) {
1108 clk->parents[i] = __clk_lookup(parent->name);
1116 static void clk_reparent(struct clk *clk, struct clk *new_parent)
1118 hlist_del(&clk->child_node);
1121 /* avoid duplicate POST_RATE_CHANGE notifications */
1122 if (new_parent->new_child == clk)
1123 new_parent->new_child = NULL;
1125 hlist_add_head(&clk->child_node, &new_parent->children);
1127 hlist_add_head(&clk->child_node, &clk_orphan_list);
1130 clk->parent = new_parent;
1133 static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1135 unsigned long flags;
1137 struct clk *old_parent = clk->parent;
1140 * Migrate prepare state between parents and prevent race with
1143 * If the clock is not prepared, then a race with
1144 * clk_enable/disable() is impossible since we already have the
1145 * prepare lock (future calls to clk_enable() need to be preceded by
1148 * If the clock is prepared, migrate the prepared state to the new
1149 * parent and also protect against a race with clk_enable() by
1150 * forcing the clock and the new parent on. This ensures that all
1151 * future calls to clk_enable() are practically NOPs with respect to
1152 * hardware and software states.
1154 * See also: Comment for clk_set_parent() below.
1156 if (clk->prepare_count) {
1157 __clk_prepare(parent);
1162 /* update the clk tree topology */
1163 flags = clk_enable_lock();
1164 clk_reparent(clk, parent);
1165 clk_enable_unlock(flags);
1167 /* change clock input source */
1168 if (parent && clk->ops->set_parent)
1169 ret = clk->ops->set_parent(clk->hw, p_index);
1172 flags = clk_enable_lock();
1173 clk_reparent(clk, old_parent);
1174 clk_enable_unlock(flags);
1176 if (clk->prepare_count) {
1178 clk_disable(parent);
1179 __clk_unprepare(parent);
1185 * Finish the migration of prepare state and undo the changes done
1186 * for preventing a race with clk_enable().
1188 if (clk->prepare_count) {
1190 clk_disable(old_parent);
1191 __clk_unprepare(old_parent);
1194 /* update debugfs with new clk tree topology */
1195 clk_debug_reparent(clk, parent);
1200 * __clk_speculate_rates
1201 * @clk: first clk in the subtree
1202 * @parent_rate: the "future" rate of clk's parent
1204 * Walks the subtree of clks starting with clk, speculating rates as it
1205 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1207 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1208 * pre-rate change notifications and returns early if no clks in the
1209 * subtree have subscribed to the notifications. Note that if a clk does not
1210 * implement the .recalc_rate callback then it is assumed that the clock will
1211 * take on the rate of its parent.
1213 * Caller must hold prepare_lock.
1215 static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1218 unsigned long new_rate;
1219 int ret = NOTIFY_DONE;
1221 if (clk->ops->recalc_rate)
1222 new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1224 new_rate = parent_rate;
1226 /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1227 if (clk->notifier_count)
1228 ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1230 if (ret & NOTIFY_STOP_MASK)
1233 hlist_for_each_entry(child, &clk->children, child_node) {
1234 ret = __clk_speculate_rates(child, new_rate);
1235 if (ret & NOTIFY_STOP_MASK)
1243 static void clk_calc_subtree(struct clk *clk, unsigned long new_rate,
1244 struct clk *new_parent, u8 p_index)
1248 clk->new_rate = new_rate;
1249 clk->new_parent = new_parent;
1250 clk->new_parent_index = p_index;
1251 /* include clk in new parent's PRE_RATE_CHANGE notifications */
1252 clk->new_child = NULL;
1253 if (new_parent && new_parent != clk->parent)
1254 new_parent->new_child = clk;
1256 hlist_for_each_entry(child, &clk->children, child_node) {
1257 if (child->ops->recalc_rate)
1258 child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
1260 child->new_rate = new_rate;
1261 clk_calc_subtree(child, child->new_rate, NULL, 0);
1266 * calculate the new rates returning the topmost clock that has to be
1269 static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1271 struct clk *top = clk;
1272 struct clk *old_parent, *parent;
1273 unsigned long best_parent_rate = 0;
1274 unsigned long new_rate;
1278 if (IS_ERR_OR_NULL(clk))
1281 /* save parent rate, if it exists */
1282 parent = old_parent = clk->parent;
1284 best_parent_rate = parent->rate;
1286 /* find the closest rate and parent clk/rate */
1287 if (clk->ops->determine_rate) {
1288 new_rate = clk->ops->determine_rate(clk->hw, rate,
1291 } else if (clk->ops->round_rate) {
1292 new_rate = clk->ops->round_rate(clk->hw, rate,
1294 } else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
1295 /* pass-through clock without adjustable parent */
1296 clk->new_rate = clk->rate;
1299 /* pass-through clock with adjustable parent */
1300 top = clk_calc_new_rates(parent, rate);
1301 new_rate = parent->new_rate;
1305 /* some clocks must be gated to change parent */
1306 if (parent != old_parent &&
1307 (clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1308 pr_debug("%s: %s not gated but wants to reparent\n",
1309 __func__, clk->name);
1313 /* try finding the new parent index */
1315 p_index = clk_fetch_parent_index(clk, parent);
1317 pr_debug("%s: clk %s can not be parent of clk %s\n",
1318 __func__, parent->name, clk->name);
1323 if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
1324 best_parent_rate != parent->rate)
1325 top = clk_calc_new_rates(parent, best_parent_rate);
1328 clk_calc_subtree(clk, new_rate, parent, p_index);
1334 * Notify about rate changes in a subtree. Always walk down the whole tree
1335 * so that in case of an error we can walk down the whole tree again and
1338 static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1340 struct clk *child, *tmp_clk, *fail_clk = NULL;
1341 int ret = NOTIFY_DONE;
1343 if (clk->rate == clk->new_rate)
1346 if (clk->notifier_count) {
1347 ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1348 if (ret & NOTIFY_STOP_MASK)
1352 hlist_for_each_entry(child, &clk->children, child_node) {
1353 /* Skip children who will be reparented to another clock */
1354 if (child->new_parent && child->new_parent != clk)
1356 tmp_clk = clk_propagate_rate_change(child, event);
1361 /* handle the new child who might not be in clk->children yet */
1362 if (clk->new_child) {
1363 tmp_clk = clk_propagate_rate_change(clk->new_child, event);
1372 * walk down a subtree and set the new rates notifying the rate
1375 static void clk_change_rate(struct clk *clk)
1378 unsigned long old_rate;
1379 unsigned long best_parent_rate = 0;
1381 old_rate = clk->rate;
1384 if (clk->new_parent && clk->new_parent != clk->parent)
1385 __clk_set_parent(clk, clk->new_parent, clk->new_parent_index);
1388 best_parent_rate = clk->parent->rate;
1390 if (clk->ops->set_rate)
1391 clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1393 if (clk->ops->recalc_rate)
1394 clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
1396 clk->rate = best_parent_rate;
1398 if (clk->notifier_count && old_rate != clk->rate)
1399 __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1401 hlist_for_each_entry(child, &clk->children, child_node) {
1402 /* Skip children who will be reparented to another clock */
1403 if (child->new_parent && child->new_parent != clk)
1405 clk_change_rate(child);
1408 /* handle the new child who might not be in clk->children yet */
1410 clk_change_rate(clk->new_child);
1414 * clk_set_rate - specify a new rate for clk
1415 * @clk: the clk whose rate is being changed
1416 * @rate: the new rate for clk
1418 * In the simplest case clk_set_rate will only adjust the rate of clk.
1420 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1421 * propagate up to clk's parent; whether or not this happens depends on the
1422 * outcome of clk's .round_rate implementation. If *parent_rate is unchanged
1423 * after calling .round_rate then upstream parent propagation is ignored. If
1424 * *parent_rate comes back with a new rate for clk's parent then we propagate
1425 * up to clk's parent and set its rate. Upward propagation will continue
1426 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1427 * .round_rate stops requesting changes to clk's parent_rate.
1429 * Rate changes are accomplished via tree traversal that also recalculates the
1430 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1432 * Returns 0 on success, -EERROR otherwise.
1434 int clk_set_rate(struct clk *clk, unsigned long rate)
1436 struct clk *top, *fail_clk;
1442 /* prevent racing with updates to the clock topology */
1445 /* bail early if nothing to do */
1446 if (rate == clk_get_rate(clk))
1449 if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1454 /* calculate new rates and get the topmost changed clock */
1455 top = clk_calc_new_rates(clk, rate);
1461 /* notify that we are about to change rates */
1462 fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1464 pr_warn("%s: failed to set %s rate\n", __func__,
1466 clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1471 /* change the rates */
1472 clk_change_rate(top);
1475 clk_prepare_unlock();
1479 EXPORT_SYMBOL_GPL(clk_set_rate);
1482 * clk_get_parent - return the parent of a clk
1483 * @clk: the clk whose parent gets returned
1485 * Simply returns clk->parent. Returns NULL if clk is NULL.
1487 struct clk *clk_get_parent(struct clk *clk)
1492 parent = __clk_get_parent(clk);
1493 clk_prepare_unlock();
1497 EXPORT_SYMBOL_GPL(clk_get_parent);
1500 * .get_parent is mandatory for clocks with multiple possible parents. It is
1501 * optional for single-parent clocks. Always call .get_parent if it is
1502 * available and WARN if it is missing for multi-parent clocks.
1504 * For single-parent clocks without .get_parent, first check to see if the
1505 * .parents array exists, and if so use it to avoid an expensive tree
1506 * traversal. If .parents does not exist then walk the tree with __clk_lookup.
1508 static struct clk *__clk_init_parent(struct clk *clk)
1510 struct clk *ret = NULL;
1513 /* handle the trivial cases */
1515 if (!clk->num_parents)
1518 if (clk->num_parents == 1) {
1519 if (IS_ERR_OR_NULL(clk->parent))
1520 ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1525 if (!clk->ops->get_parent) {
1526 WARN(!clk->ops->get_parent,
1527 "%s: multi-parent clocks must implement .get_parent\n",
1533 * Do our best to cache parent clocks in clk->parents. This prevents
1534 * unnecessary and expensive calls to __clk_lookup. We don't set
1535 * clk->parent here; that is done by the calling function
1538 index = clk->ops->get_parent(clk->hw);
1542 kcalloc(clk->num_parents, sizeof(struct clk *),
1545 ret = clk_get_parent_by_index(clk, index);
1551 void __clk_reparent(struct clk *clk, struct clk *new_parent)
1553 clk_reparent(clk, new_parent);
1554 clk_debug_reparent(clk, new_parent);
1555 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1559 * clk_set_parent - switch the parent of a mux clk
1560 * @clk: the mux clk whose input we are switching
1561 * @parent: the new input to clk
1563 * Re-parent clk to use parent as its new input source. If clk is in
1564 * prepared state, the clk will get enabled for the duration of this call. If
1565 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1566 * that, the reparenting is glitchy in hardware, etc), use the
1567 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1569 * After successfully changing clk's parent clk_set_parent will update the
1570 * clk topology, sysfs topology and propagate rate recalculation via
1571 * __clk_recalc_rates.
1573 * Returns 0 on success, -EERROR otherwise.
1575 int clk_set_parent(struct clk *clk, struct clk *parent)
1579 unsigned long p_rate = 0;
1587 /* verify ops for for multi-parent clks */
1588 if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1591 /* prevent racing with updates to the clock topology */
1594 if (clk->parent == parent)
1597 /* check that we are allowed to re-parent if the clock is in use */
1598 if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1603 /* try finding the new parent index */
1605 p_index = clk_fetch_parent_index(clk, parent);
1606 p_rate = parent->rate;
1608 pr_debug("%s: clk %s can not be parent of clk %s\n",
1609 __func__, parent->name, clk->name);
1615 /* propagate PRE_RATE_CHANGE notifications */
1616 ret = __clk_speculate_rates(clk, p_rate);
1618 /* abort if a driver objects */
1619 if (ret & NOTIFY_STOP_MASK)
1622 /* do the re-parent */
1623 ret = __clk_set_parent(clk, parent, p_index);
1625 /* propagate rate recalculation accordingly */
1627 __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1629 __clk_recalc_rates(clk, POST_RATE_CHANGE);
1632 clk_prepare_unlock();
1636 EXPORT_SYMBOL_GPL(clk_set_parent);
1639 * __clk_init - initialize the data structures in a struct clk
1640 * @dev: device initializing this clk, placeholder for now
1641 * @clk: clk being initialized
1643 * Initializes the lists in struct clk, queries the hardware for the
1644 * parent and rate and sets them both.
1646 int __clk_init(struct device *dev, struct clk *clk)
1650 struct hlist_node *tmp2;
1657 /* check to see if a clock with this name is already registered */
1658 if (__clk_lookup(clk->name)) {
1659 pr_debug("%s: clk %s already initialized\n",
1660 __func__, clk->name);
1665 /* check that clk_ops are sane. See Documentation/clk.txt */
1666 if (clk->ops->set_rate &&
1667 !((clk->ops->round_rate || clk->ops->determine_rate) &&
1668 clk->ops->recalc_rate)) {
1669 pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
1670 __func__, clk->name);
1675 if (clk->ops->set_parent && !clk->ops->get_parent) {
1676 pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1677 __func__, clk->name);
1682 /* throw a WARN if any entries in parent_names are NULL */
1683 for (i = 0; i < clk->num_parents; i++)
1684 WARN(!clk->parent_names[i],
1685 "%s: invalid NULL in %s's .parent_names\n",
1686 __func__, clk->name);
1689 * Allocate an array of struct clk *'s to avoid unnecessary string
1690 * look-ups of clk's possible parents. This can fail for clocks passed
1691 * in to clk_init during early boot; thus any access to clk->parents[]
1692 * must always check for a NULL pointer and try to populate it if
1695 * If clk->parents is not NULL we skip this entire block. This allows
1696 * for clock drivers to statically initialize clk->parents.
1698 if (clk->num_parents > 1 && !clk->parents) {
1699 clk->parents = kcalloc(clk->num_parents, sizeof(struct clk *),
1702 * __clk_lookup returns NULL for parents that have not been
1703 * clk_init'd; thus any access to clk->parents[] must check
1704 * for a NULL pointer. We can always perform lazy lookups for
1705 * missing parents later on.
1708 for (i = 0; i < clk->num_parents; i++)
1710 __clk_lookup(clk->parent_names[i]);
1713 clk->parent = __clk_init_parent(clk);
1716 * Populate clk->parent if parent has already been __clk_init'd. If
1717 * parent has not yet been __clk_init'd then place clk in the orphan
1718 * list. If clk has set the CLK_IS_ROOT flag then place it in the root
1721 * Every time a new clk is clk_init'd then we walk the list of orphan
1722 * clocks and re-parent any that are children of the clock currently
1726 hlist_add_head(&clk->child_node,
1727 &clk->parent->children);
1728 else if (clk->flags & CLK_IS_ROOT)
1729 hlist_add_head(&clk->child_node, &clk_root_list);
1731 hlist_add_head(&clk->child_node, &clk_orphan_list);
1734 * Set clk's rate. The preferred method is to use .recalc_rate. For
1735 * simple clocks and lazy developers the default fallback is to use the
1736 * parent's rate. If a clock doesn't have a parent (or is orphaned)
1737 * then rate is set to zero.
1739 if (clk->ops->recalc_rate)
1740 clk->rate = clk->ops->recalc_rate(clk->hw,
1741 __clk_get_rate(clk->parent));
1742 else if (clk->parent)
1743 clk->rate = clk->parent->rate;
1748 * walk the list of orphan clocks and reparent any that are children of
1751 hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1752 if (orphan->num_parents && orphan->ops->get_parent) {
1753 i = orphan->ops->get_parent(orphan->hw);
1754 if (!strcmp(clk->name, orphan->parent_names[i]))
1755 __clk_reparent(orphan, clk);
1759 for (i = 0; i < orphan->num_parents; i++)
1760 if (!strcmp(clk->name, orphan->parent_names[i])) {
1761 __clk_reparent(orphan, clk);
1767 * optional platform-specific magic
1769 * The .init callback is not used by any of the basic clock types, but
1770 * exists for weird hardware that must perform initialization magic.
1771 * Please consider other ways of solving initialization problems before
1772 * using this callback, as its use is discouraged.
1775 clk->ops->init(clk->hw);
1777 clk_debug_register(clk);
1780 clk_prepare_unlock();
1786 * __clk_register - register a clock and return a cookie.
1788 * Same as clk_register, except that the .clk field inside hw shall point to a
1789 * preallocated (generally statically allocated) struct clk. None of the fields
1790 * of the struct clk need to be initialized.
1792 * The data pointed to by .init and .clk field shall NOT be marked as init
1795 * __clk_register is only exposed via clk-private.h and is intended for use with
1796 * very large numbers of clocks that need to be statically initialized. It is
1797 * a layering violation to include clk-private.h from any code which implements
1798 * a clock's .ops; as such any statically initialized clock data MUST be in a
1799 * separate C file from the logic that implements its operations. Returns 0
1800 * on success, otherwise an error code.
1802 struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1808 clk->name = hw->init->name;
1809 clk->ops = hw->init->ops;
1811 clk->flags = hw->init->flags;
1812 clk->parent_names = hw->init->parent_names;
1813 clk->num_parents = hw->init->num_parents;
1815 ret = __clk_init(dev, clk);
1817 return ERR_PTR(ret);
1821 EXPORT_SYMBOL_GPL(__clk_register);
1823 static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
1827 clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1829 pr_err("%s: could not allocate clk->name\n", __func__);
1833 clk->ops = hw->init->ops;
1835 clk->flags = hw->init->flags;
1836 clk->num_parents = hw->init->num_parents;
1839 /* allocate local copy in case parent_names is __initdata */
1840 clk->parent_names = kcalloc(clk->num_parents, sizeof(char *),
1843 if (!clk->parent_names) {
1844 pr_err("%s: could not allocate clk->parent_names\n", __func__);
1846 goto fail_parent_names;
1850 /* copy each string name in case parent_names is __initdata */
1851 for (i = 0; i < clk->num_parents; i++) {
1852 clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1854 if (!clk->parent_names[i]) {
1855 pr_err("%s: could not copy parent_names\n", __func__);
1857 goto fail_parent_names_copy;
1861 ret = __clk_init(dev, clk);
1865 fail_parent_names_copy:
1867 kfree(clk->parent_names[i]);
1868 kfree(clk->parent_names);
1876 * clk_register - allocate a new clock, register it and return an opaque cookie
1877 * @dev: device that is registering this clock
1878 * @hw: link to hardware-specific clock data
1880 * clk_register is the primary interface for populating the clock tree with new
1881 * clock nodes. It returns a pointer to the newly allocated struct clk which
1882 * cannot be dereferenced by driver code but may be used in conjuction with the
1883 * rest of the clock API. In the event of an error clk_register will return an
1884 * error code; drivers must test for an error code after calling clk_register.
1886 struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1891 clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1893 pr_err("%s: could not allocate clk\n", __func__);
1898 ret = _clk_register(dev, hw, clk);
1904 return ERR_PTR(ret);
1906 EXPORT_SYMBOL_GPL(clk_register);
1909 * clk_unregister - unregister a currently registered clock
1910 * @clk: clock to unregister
1912 * Currently unimplemented.
1914 void clk_unregister(struct clk *clk) {}
1915 EXPORT_SYMBOL_GPL(clk_unregister);
1917 static void devm_clk_release(struct device *dev, void *res)
1919 clk_unregister(res);
1923 * devm_clk_register - resource managed clk_register()
1924 * @dev: device that is registering this clock
1925 * @hw: link to hardware-specific clock data
1927 * Managed clk_register(). Clocks returned from this function are
1928 * automatically clk_unregister()ed on driver detach. See clk_register() for
1931 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
1936 clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
1938 return ERR_PTR(-ENOMEM);
1940 ret = _clk_register(dev, hw, clk);
1942 devres_add(dev, clk);
1950 EXPORT_SYMBOL_GPL(devm_clk_register);
1952 static int devm_clk_match(struct device *dev, void *res, void *data)
1954 struct clk *c = res;
1961 * devm_clk_unregister - resource managed clk_unregister()
1962 * @clk: clock to unregister
1964 * Deallocate a clock allocated with devm_clk_register(). Normally
1965 * this function will not need to be called and the resource management
1966 * code will ensure that the resource is freed.
1968 void devm_clk_unregister(struct device *dev, struct clk *clk)
1970 WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
1972 EXPORT_SYMBOL_GPL(devm_clk_unregister);
1974 /*** clk rate change notifiers ***/
1977 * clk_notifier_register - add a clk rate change notifier
1978 * @clk: struct clk * to watch
1979 * @nb: struct notifier_block * with callback info
1981 * Request notification when clk's rate changes. This uses an SRCU
1982 * notifier because we want it to block and notifier unregistrations are
1983 * uncommon. The callbacks associated with the notifier must not
1984 * re-enter into the clk framework by calling any top-level clk APIs;
1985 * this will cause a nested prepare_lock mutex.
1987 * Pre-change notifier callbacks will be passed the current, pre-change
1988 * rate of the clk via struct clk_notifier_data.old_rate. The new,
1989 * post-change rate of the clk is passed via struct
1990 * clk_notifier_data.new_rate.
1992 * Post-change notifiers will pass the now-current, post-change rate of
1993 * the clk in both struct clk_notifier_data.old_rate and struct
1994 * clk_notifier_data.new_rate.
1996 * Abort-change notifiers are effectively the opposite of pre-change
1997 * notifiers: the original pre-change clk rate is passed in via struct
1998 * clk_notifier_data.new_rate and the failed post-change rate is passed
1999 * in via struct clk_notifier_data.old_rate.
2001 * clk_notifier_register() must be called from non-atomic context.
2002 * Returns -EINVAL if called with null arguments, -ENOMEM upon
2003 * allocation failure; otherwise, passes along the return value of
2004 * srcu_notifier_chain_register().
2006 int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
2008 struct clk_notifier *cn;
2016 /* search the list of notifiers for this clk */
2017 list_for_each_entry(cn, &clk_notifier_list, node)
2021 /* if clk wasn't in the notifier list, allocate new clk_notifier */
2022 if (cn->clk != clk) {
2023 cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
2028 srcu_init_notifier_head(&cn->notifier_head);
2030 list_add(&cn->node, &clk_notifier_list);
2033 ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
2035 clk->notifier_count++;
2038 clk_prepare_unlock();
2042 EXPORT_SYMBOL_GPL(clk_notifier_register);
2045 * clk_notifier_unregister - remove a clk rate change notifier
2046 * @clk: struct clk *
2047 * @nb: struct notifier_block * with callback info
2049 * Request no further notification for changes to 'clk' and frees memory
2050 * allocated in clk_notifier_register.
2052 * Returns -EINVAL if called with null arguments; otherwise, passes
2053 * along the return value of srcu_notifier_chain_unregister().
2055 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
2057 struct clk_notifier *cn = NULL;
2065 list_for_each_entry(cn, &clk_notifier_list, node)
2069 if (cn->clk == clk) {
2070 ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
2072 clk->notifier_count--;
2074 /* XXX the notifier code should handle this better */
2075 if (!cn->notifier_head.head) {
2076 srcu_cleanup_notifier_head(&cn->notifier_head);
2077 list_del(&cn->node);
2085 clk_prepare_unlock();
2089 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
2093 * struct of_clk_provider - Clock provider registration structure
2094 * @link: Entry in global list of clock providers
2095 * @node: Pointer to device tree node of clock provider
2096 * @get: Get clock callback. Returns NULL or a struct clk for the
2097 * given clock specifier
2098 * @data: context pointer to be passed into @get callback
2100 struct of_clk_provider {
2101 struct list_head link;
2103 struct device_node *node;
2104 struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
2108 extern struct of_device_id __clk_of_table[];
2110 static const struct of_device_id __clk_of_table_sentinel
2111 __used __section(__clk_of_table_end);
2113 static LIST_HEAD(of_clk_providers);
2114 static DEFINE_MUTEX(of_clk_lock);
2116 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
2121 EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2123 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2125 struct clk_onecell_data *clk_data = data;
2126 unsigned int idx = clkspec->args[0];
2128 if (idx >= clk_data->clk_num) {
2129 pr_err("%s: invalid clock index %d\n", __func__, idx);
2130 return ERR_PTR(-EINVAL);
2133 return clk_data->clks[idx];
2135 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2138 * of_clk_add_provider() - Register a clock provider for a node
2139 * @np: Device node pointer associated with clock provider
2140 * @clk_src_get: callback for decoding clock
2141 * @data: context pointer for @clk_src_get callback.
2143 int of_clk_add_provider(struct device_node *np,
2144 struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2148 struct of_clk_provider *cp;
2150 cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2154 cp->node = of_node_get(np);
2156 cp->get = clk_src_get;
2158 mutex_lock(&of_clk_lock);
2159 list_add(&cp->link, &of_clk_providers);
2160 mutex_unlock(&of_clk_lock);
2161 pr_debug("Added clock from %s\n", np->full_name);
2165 EXPORT_SYMBOL_GPL(of_clk_add_provider);
2168 * of_clk_del_provider() - Remove a previously registered clock provider
2169 * @np: Device node pointer associated with clock provider
2171 void of_clk_del_provider(struct device_node *np)
2173 struct of_clk_provider *cp;
2175 mutex_lock(&of_clk_lock);
2176 list_for_each_entry(cp, &of_clk_providers, link) {
2177 if (cp->node == np) {
2178 list_del(&cp->link);
2179 of_node_put(cp->node);
2184 mutex_unlock(&of_clk_lock);
2186 EXPORT_SYMBOL_GPL(of_clk_del_provider);
2188 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2190 struct of_clk_provider *provider;
2191 struct clk *clk = ERR_PTR(-ENOENT);
2193 /* Check if we have such a provider in our array */
2194 mutex_lock(&of_clk_lock);
2195 list_for_each_entry(provider, &of_clk_providers, link) {
2196 if (provider->node == clkspec->np)
2197 clk = provider->get(clkspec, provider->data);
2201 mutex_unlock(&of_clk_lock);
2206 int of_clk_get_parent_count(struct device_node *np)
2208 return of_count_phandle_with_args(np, "clocks", "#clock-cells");
2210 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
2212 const char *of_clk_get_parent_name(struct device_node *np, int index)
2214 struct of_phandle_args clkspec;
2215 const char *clk_name;
2221 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2226 if (of_property_read_string_index(clkspec.np, "clock-output-names",
2227 clkspec.args_count ? clkspec.args[0] : 0,
2229 clk_name = clkspec.np->name;
2231 of_node_put(clkspec.np);
2234 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2237 * of_clk_init() - Scan and init clock providers from the DT
2238 * @matches: array of compatible values and init functions for providers.
2240 * This function scans the device tree for matching clock providers and
2241 * calls their initialization functions
2243 void __init of_clk_init(const struct of_device_id *matches)
2245 const struct of_device_id *match;
2246 struct device_node *np;
2249 matches = __clk_of_table;
2251 for_each_matching_node_and_match(np, matches, &match) {
2252 of_clk_init_cb_t clk_init_cb = match->data;