mirror of https://gitee.com/openkylin/linux.git
1555 lines
38 KiB
C
1555 lines
38 KiB
C
/*
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* Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
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* Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Standard functionality for the common clock API. See Documentation/clk.txt
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*/
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#include <linux/clk-private.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/err.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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static DEFINE_SPINLOCK(enable_lock);
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static DEFINE_MUTEX(prepare_lock);
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static HLIST_HEAD(clk_root_list);
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static HLIST_HEAD(clk_orphan_list);
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static LIST_HEAD(clk_notifier_list);
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/*** debugfs support ***/
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#ifdef CONFIG_COMMON_CLK_DEBUG
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#include <linux/debugfs.h>
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static struct dentry *rootdir;
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static struct dentry *orphandir;
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static int inited = 0;
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/* caller must hold prepare_lock */
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static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
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{
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struct dentry *d;
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int ret = -ENOMEM;
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if (!clk || !pdentry) {
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ret = -EINVAL;
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goto out;
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}
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d = debugfs_create_dir(clk->name, pdentry);
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if (!d)
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goto out;
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clk->dentry = d;
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d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
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(u32 *)&clk->rate);
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if (!d)
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goto err_out;
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d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
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(u32 *)&clk->flags);
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if (!d)
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goto err_out;
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d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
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(u32 *)&clk->prepare_count);
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if (!d)
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goto err_out;
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d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
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(u32 *)&clk->enable_count);
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if (!d)
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goto err_out;
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d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
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(u32 *)&clk->notifier_count);
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if (!d)
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goto err_out;
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ret = 0;
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goto out;
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err_out:
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debugfs_remove(clk->dentry);
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out:
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return ret;
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}
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/* caller must hold prepare_lock */
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static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
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{
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struct clk *child;
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struct hlist_node *tmp;
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int ret = -EINVAL;;
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if (!clk || !pdentry)
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goto out;
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ret = clk_debug_create_one(clk, pdentry);
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if (ret)
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goto out;
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hlist_for_each_entry(child, tmp, &clk->children, child_node)
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clk_debug_create_subtree(child, clk->dentry);
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ret = 0;
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out:
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return ret;
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}
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/**
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* clk_debug_register - add a clk node to the debugfs clk tree
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* @clk: the clk being added to the debugfs clk tree
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*
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* Dynamically adds a clk to the debugfs clk tree if debugfs has been
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* initialized. Otherwise it bails out early since the debugfs clk tree
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* will be created lazily by clk_debug_init as part of a late_initcall.
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*
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* Caller must hold prepare_lock. Only clk_init calls this function (so
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* far) so this is taken care.
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*/
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static int clk_debug_register(struct clk *clk)
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{
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struct clk *parent;
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struct dentry *pdentry;
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int ret = 0;
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if (!inited)
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goto out;
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parent = clk->parent;
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/*
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* Check to see if a clk is a root clk. Also check that it is
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* safe to add this clk to debugfs
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*/
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if (!parent)
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if (clk->flags & CLK_IS_ROOT)
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pdentry = rootdir;
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else
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pdentry = orphandir;
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else
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if (parent->dentry)
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pdentry = parent->dentry;
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else
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goto out;
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ret = clk_debug_create_subtree(clk, pdentry);
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out:
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return ret;
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}
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/**
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* clk_debug_init - lazily create the debugfs clk tree visualization
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*
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* clks are often initialized very early during boot before memory can
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* be dynamically allocated and well before debugfs is setup.
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* clk_debug_init walks the clk tree hierarchy while holding
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* prepare_lock and creates the topology as part of a late_initcall,
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* thus insuring that clks initialized very early will still be
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* represented in the debugfs clk tree. This function should only be
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* called once at boot-time, and all other clks added dynamically will
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* be done so with clk_debug_register.
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*/
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static int __init clk_debug_init(void)
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{
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struct clk *clk;
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struct hlist_node *tmp;
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rootdir = debugfs_create_dir("clk", NULL);
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if (!rootdir)
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return -ENOMEM;
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orphandir = debugfs_create_dir("orphans", rootdir);
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if (!orphandir)
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return -ENOMEM;
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mutex_lock(&prepare_lock);
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hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
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clk_debug_create_subtree(clk, rootdir);
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hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
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clk_debug_create_subtree(clk, orphandir);
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inited = 1;
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mutex_unlock(&prepare_lock);
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return 0;
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}
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late_initcall(clk_debug_init);
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#else
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static inline int clk_debug_register(struct clk *clk) { return 0; }
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#endif
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/* caller must hold prepare_lock */
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static void clk_disable_unused_subtree(struct clk *clk)
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{
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struct clk *child;
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struct hlist_node *tmp;
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unsigned long flags;
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if (!clk)
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goto out;
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hlist_for_each_entry(child, tmp, &clk->children, child_node)
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clk_disable_unused_subtree(child);
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spin_lock_irqsave(&enable_lock, flags);
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if (clk->enable_count)
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goto unlock_out;
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if (clk->flags & CLK_IGNORE_UNUSED)
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goto unlock_out;
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if (__clk_is_enabled(clk) && clk->ops->disable)
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clk->ops->disable(clk->hw);
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unlock_out:
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spin_unlock_irqrestore(&enable_lock, flags);
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out:
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return;
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}
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static int clk_disable_unused(void)
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{
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struct clk *clk;
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struct hlist_node *tmp;
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mutex_lock(&prepare_lock);
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hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
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clk_disable_unused_subtree(clk);
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hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
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clk_disable_unused_subtree(clk);
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mutex_unlock(&prepare_lock);
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return 0;
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}
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late_initcall(clk_disable_unused);
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/*** helper functions ***/
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inline const char *__clk_get_name(struct clk *clk)
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{
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return !clk ? NULL : clk->name;
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}
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inline struct clk_hw *__clk_get_hw(struct clk *clk)
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{
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return !clk ? NULL : clk->hw;
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}
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inline u8 __clk_get_num_parents(struct clk *clk)
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{
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return !clk ? -EINVAL : clk->num_parents;
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}
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inline struct clk *__clk_get_parent(struct clk *clk)
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{
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return !clk ? NULL : clk->parent;
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}
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inline int __clk_get_enable_count(struct clk *clk)
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{
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return !clk ? -EINVAL : clk->enable_count;
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}
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inline int __clk_get_prepare_count(struct clk *clk)
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{
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return !clk ? -EINVAL : clk->prepare_count;
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}
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unsigned long __clk_get_rate(struct clk *clk)
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{
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unsigned long ret;
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if (!clk) {
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ret = 0;
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goto out;
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}
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ret = clk->rate;
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if (clk->flags & CLK_IS_ROOT)
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goto out;
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if (!clk->parent)
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ret = 0;
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out:
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return ret;
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}
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inline unsigned long __clk_get_flags(struct clk *clk)
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{
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return !clk ? -EINVAL : clk->flags;
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}
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int __clk_is_enabled(struct clk *clk)
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{
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int ret;
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if (!clk)
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return -EINVAL;
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/*
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* .is_enabled is only mandatory for clocks that gate
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* fall back to software usage counter if .is_enabled is missing
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*/
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if (!clk->ops->is_enabled) {
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ret = clk->enable_count ? 1 : 0;
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goto out;
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}
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ret = clk->ops->is_enabled(clk->hw);
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out:
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return ret;
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}
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static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
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{
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struct clk *child;
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struct clk *ret;
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struct hlist_node *tmp;
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if (!strcmp(clk->name, name))
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return clk;
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hlist_for_each_entry(child, tmp, &clk->children, child_node) {
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ret = __clk_lookup_subtree(name, child);
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if (ret)
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return ret;
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}
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return NULL;
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}
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struct clk *__clk_lookup(const char *name)
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{
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struct clk *root_clk;
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struct clk *ret;
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struct hlist_node *tmp;
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if (!name)
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return NULL;
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/* search the 'proper' clk tree first */
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hlist_for_each_entry(root_clk, tmp, &clk_root_list, child_node) {
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ret = __clk_lookup_subtree(name, root_clk);
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if (ret)
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return ret;
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}
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/* if not found, then search the orphan tree */
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hlist_for_each_entry(root_clk, tmp, &clk_orphan_list, child_node) {
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ret = __clk_lookup_subtree(name, root_clk);
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if (ret)
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return ret;
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}
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return NULL;
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}
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/*** clk api ***/
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void __clk_unprepare(struct clk *clk)
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{
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if (!clk)
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return;
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if (WARN_ON(clk->prepare_count == 0))
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return;
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if (--clk->prepare_count > 0)
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return;
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WARN_ON(clk->enable_count > 0);
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if (clk->ops->unprepare)
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clk->ops->unprepare(clk->hw);
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__clk_unprepare(clk->parent);
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}
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/**
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* clk_unprepare - undo preparation of a clock source
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* @clk: the clk being unprepare
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*
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* clk_unprepare may sleep, which differentiates it from clk_disable. In a
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* simple case, clk_unprepare can be used instead of clk_disable to gate a clk
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* if the operation may sleep. One example is a clk which is accessed over
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* I2c. In the complex case a clk gate operation may require a fast and a slow
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* part. It is this reason that clk_unprepare and clk_disable are not mutually
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* exclusive. In fact clk_disable must be called before clk_unprepare.
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*/
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void clk_unprepare(struct clk *clk)
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{
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mutex_lock(&prepare_lock);
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__clk_unprepare(clk);
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mutex_unlock(&prepare_lock);
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}
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EXPORT_SYMBOL_GPL(clk_unprepare);
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int __clk_prepare(struct clk *clk)
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{
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int ret = 0;
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if (!clk)
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return 0;
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if (clk->prepare_count == 0) {
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ret = __clk_prepare(clk->parent);
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if (ret)
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return ret;
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if (clk->ops->prepare) {
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ret = clk->ops->prepare(clk->hw);
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if (ret) {
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__clk_unprepare(clk->parent);
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return ret;
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}
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}
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}
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clk->prepare_count++;
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return 0;
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}
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/**
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* clk_prepare - prepare a clock source
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* @clk: the clk being prepared
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*
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* clk_prepare may sleep, which differentiates it from clk_enable. In a simple
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* case, clk_prepare can be used instead of clk_enable to ungate a clk if the
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* operation may sleep. One example is a clk which is accessed over I2c. In
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* the complex case a clk ungate operation may require a fast and a slow part.
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* It is this reason that clk_prepare and clk_enable are not mutually
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* exclusive. In fact clk_prepare must be called before clk_enable.
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* Returns 0 on success, -EERROR otherwise.
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*/
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int clk_prepare(struct clk *clk)
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{
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int ret;
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mutex_lock(&prepare_lock);
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ret = __clk_prepare(clk);
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mutex_unlock(&prepare_lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(clk_prepare);
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static void __clk_disable(struct clk *clk)
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{
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if (!clk)
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return;
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if (WARN_ON(clk->enable_count == 0))
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return;
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if (--clk->enable_count > 0)
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return;
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if (clk->ops->disable)
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clk->ops->disable(clk->hw);
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__clk_disable(clk->parent);
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}
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/**
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* clk_disable - gate a clock
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* @clk: the clk being gated
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*
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* clk_disable must not sleep, which differentiates it from clk_unprepare. In
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* a simple case, clk_disable can be used instead of clk_unprepare to gate a
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* clk if the operation is fast and will never sleep. One example is a
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* SoC-internal clk which is controlled via simple register writes. In the
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* complex case a clk gate operation may require a fast and a slow part. It is
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* this reason that clk_unprepare and clk_disable are not mutually exclusive.
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* In fact clk_disable must be called before clk_unprepare.
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*/
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void clk_disable(struct clk *clk)
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{
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unsigned long flags;
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spin_lock_irqsave(&enable_lock, flags);
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__clk_disable(clk);
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spin_unlock_irqrestore(&enable_lock, flags);
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}
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EXPORT_SYMBOL_GPL(clk_disable);
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|
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static int __clk_enable(struct clk *clk)
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{
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int ret = 0;
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if (!clk)
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return 0;
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|
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if (WARN_ON(clk->prepare_count == 0))
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return -ESHUTDOWN;
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|
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if (clk->enable_count == 0) {
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ret = __clk_enable(clk->parent);
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|
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if (ret)
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return ret;
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|
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if (clk->ops->enable) {
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ret = clk->ops->enable(clk->hw);
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if (ret) {
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__clk_disable(clk->parent);
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return ret;
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}
|
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}
|
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}
|
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|
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clk->enable_count++;
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return 0;
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}
|
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|
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/**
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* clk_enable - ungate a clock
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* @clk: the clk being ungated
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*
|
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* clk_enable must not sleep, which differentiates it from clk_prepare. In a
|
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* simple case, clk_enable can be used instead of clk_prepare to ungate a clk
|
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* if the operation will never sleep. One example is a SoC-internal clk which
|
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* is controlled via simple register writes. In the complex case a clk ungate
|
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* operation may require a fast and a slow part. It is this reason that
|
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* clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
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* must be called before clk_enable. Returns 0 on success, -EERROR
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* otherwise.
|
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*/
|
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int clk_enable(struct clk *clk)
|
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{
|
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unsigned long flags;
|
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int ret;
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|
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spin_lock_irqsave(&enable_lock, flags);
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ret = __clk_enable(clk);
|
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spin_unlock_irqrestore(&enable_lock, flags);
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|
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return ret;
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}
|
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EXPORT_SYMBOL_GPL(clk_enable);
|
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|
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/**
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* clk_get_rate - return the rate of clk
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* @clk: the clk whose rate is being returned
|
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*
|
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* Simply returns the cached rate of the clk. Does not query the hardware. If
|
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* clk is NULL then returns 0.
|
|
*/
|
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unsigned long clk_get_rate(struct clk *clk)
|
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{
|
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unsigned long rate;
|
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|
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mutex_lock(&prepare_lock);
|
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rate = __clk_get_rate(clk);
|
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mutex_unlock(&prepare_lock);
|
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|
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return rate;
|
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}
|
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EXPORT_SYMBOL_GPL(clk_get_rate);
|
|
|
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/**
|
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* __clk_round_rate - round the given rate for a clk
|
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* @clk: round the rate of this clock
|
|
*
|
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* Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
|
|
*/
|
|
unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
|
|
{
|
|
unsigned long parent_rate = 0;
|
|
|
|
if (!clk)
|
|
return -EINVAL;
|
|
|
|
if (!clk->ops->round_rate) {
|
|
if (clk->flags & CLK_SET_RATE_PARENT)
|
|
return __clk_round_rate(clk->parent, rate);
|
|
else
|
|
return clk->rate;
|
|
}
|
|
|
|
if (clk->parent)
|
|
parent_rate = clk->parent->rate;
|
|
|
|
return clk->ops->round_rate(clk->hw, rate, &parent_rate);
|
|
}
|
|
|
|
/**
|
|
* clk_round_rate - round the given rate for a clk
|
|
* @clk: the clk for which we are rounding a rate
|
|
* @rate: the rate which is to be rounded
|
|
*
|
|
* Takes in a rate as input and rounds it to a rate that the clk can actually
|
|
* use which is then returned. If clk doesn't support round_rate operation
|
|
* then the parent rate is returned.
|
|
*/
|
|
long clk_round_rate(struct clk *clk, unsigned long rate)
|
|
{
|
|
unsigned long ret;
|
|
|
|
mutex_lock(&prepare_lock);
|
|
ret = __clk_round_rate(clk, rate);
|
|
mutex_unlock(&prepare_lock);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_round_rate);
|
|
|
|
/**
|
|
* __clk_notify - call clk notifier chain
|
|
* @clk: struct clk * that is changing rate
|
|
* @msg: clk notifier type (see include/linux/clk.h)
|
|
* @old_rate: old clk rate
|
|
* @new_rate: new clk rate
|
|
*
|
|
* Triggers a notifier call chain on the clk rate-change notification
|
|
* for 'clk'. Passes a pointer to the struct clk and the previous
|
|
* and current rates to the notifier callback. Intended to be called by
|
|
* internal clock code only. Returns NOTIFY_DONE from the last driver
|
|
* called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
|
|
* a driver returns that.
|
|
*/
|
|
static int __clk_notify(struct clk *clk, unsigned long msg,
|
|
unsigned long old_rate, unsigned long new_rate)
|
|
{
|
|
struct clk_notifier *cn;
|
|
struct clk_notifier_data cnd;
|
|
int ret = NOTIFY_DONE;
|
|
|
|
cnd.clk = clk;
|
|
cnd.old_rate = old_rate;
|
|
cnd.new_rate = new_rate;
|
|
|
|
list_for_each_entry(cn, &clk_notifier_list, node) {
|
|
if (cn->clk == clk) {
|
|
ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
|
|
&cnd);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* __clk_recalc_rates
|
|
* @clk: first clk in the subtree
|
|
* @msg: notification type (see include/linux/clk.h)
|
|
*
|
|
* Walks the subtree of clks starting with clk and recalculates rates as it
|
|
* goes. Note that if a clk does not implement the .recalc_rate callback then
|
|
* it is assumed that the clock will take on the rate of it's parent.
|
|
*
|
|
* clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
|
|
* if necessary.
|
|
*
|
|
* Caller must hold prepare_lock.
|
|
*/
|
|
static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
|
|
{
|
|
unsigned long old_rate;
|
|
unsigned long parent_rate = 0;
|
|
struct hlist_node *tmp;
|
|
struct clk *child;
|
|
|
|
old_rate = clk->rate;
|
|
|
|
if (clk->parent)
|
|
parent_rate = clk->parent->rate;
|
|
|
|
if (clk->ops->recalc_rate)
|
|
clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
|
|
else
|
|
clk->rate = parent_rate;
|
|
|
|
/*
|
|
* ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
|
|
* & ABORT_RATE_CHANGE notifiers
|
|
*/
|
|
if (clk->notifier_count && msg)
|
|
__clk_notify(clk, msg, old_rate, clk->rate);
|
|
|
|
hlist_for_each_entry(child, tmp, &clk->children, child_node)
|
|
__clk_recalc_rates(child, msg);
|
|
}
|
|
|
|
/**
|
|
* __clk_speculate_rates
|
|
* @clk: first clk in the subtree
|
|
* @parent_rate: the "future" rate of clk's parent
|
|
*
|
|
* Walks the subtree of clks starting with clk, speculating rates as it
|
|
* goes and firing off PRE_RATE_CHANGE notifications as necessary.
|
|
*
|
|
* Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
|
|
* pre-rate change notifications and returns early if no clks in the
|
|
* subtree have subscribed to the notifications. Note that if a clk does not
|
|
* implement the .recalc_rate callback then it is assumed that the clock will
|
|
* take on the rate of it's parent.
|
|
*
|
|
* Caller must hold prepare_lock.
|
|
*/
|
|
static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
|
|
{
|
|
struct hlist_node *tmp;
|
|
struct clk *child;
|
|
unsigned long new_rate;
|
|
int ret = NOTIFY_DONE;
|
|
|
|
if (clk->ops->recalc_rate)
|
|
new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
|
|
else
|
|
new_rate = parent_rate;
|
|
|
|
/* abort the rate change if a driver returns NOTIFY_BAD */
|
|
if (clk->notifier_count)
|
|
ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
|
|
|
|
if (ret == NOTIFY_BAD)
|
|
goto out;
|
|
|
|
hlist_for_each_entry(child, tmp, &clk->children, child_node) {
|
|
ret = __clk_speculate_rates(child, new_rate);
|
|
if (ret == NOTIFY_BAD)
|
|
break;
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
|
|
{
|
|
struct clk *child;
|
|
struct hlist_node *tmp;
|
|
|
|
clk->new_rate = new_rate;
|
|
|
|
hlist_for_each_entry(child, tmp, &clk->children, child_node) {
|
|
if (child->ops->recalc_rate)
|
|
child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
|
|
else
|
|
child->new_rate = new_rate;
|
|
clk_calc_subtree(child, child->new_rate);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* calculate the new rates returning the topmost clock that has to be
|
|
* changed.
|
|
*/
|
|
static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
|
|
{
|
|
struct clk *top = clk;
|
|
unsigned long best_parent_rate = 0;
|
|
unsigned long new_rate;
|
|
|
|
/* sanity */
|
|
if (IS_ERR_OR_NULL(clk))
|
|
return NULL;
|
|
|
|
/* save parent rate, if it exists */
|
|
if (clk->parent)
|
|
best_parent_rate = clk->parent->rate;
|
|
|
|
/* never propagate up to the parent */
|
|
if (!(clk->flags & CLK_SET_RATE_PARENT)) {
|
|
if (!clk->ops->round_rate) {
|
|
clk->new_rate = clk->rate;
|
|
return NULL;
|
|
}
|
|
new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
|
|
goto out;
|
|
}
|
|
|
|
/* need clk->parent from here on out */
|
|
if (!clk->parent) {
|
|
pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
|
|
return NULL;
|
|
}
|
|
|
|
if (!clk->ops->round_rate) {
|
|
top = clk_calc_new_rates(clk->parent, rate);
|
|
new_rate = clk->parent->new_rate;
|
|
|
|
goto out;
|
|
}
|
|
|
|
new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
|
|
|
|
if (best_parent_rate != clk->parent->rate) {
|
|
top = clk_calc_new_rates(clk->parent, best_parent_rate);
|
|
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
clk_calc_subtree(clk, new_rate);
|
|
|
|
return top;
|
|
}
|
|
|
|
/*
|
|
* Notify about rate changes in a subtree. Always walk down the whole tree
|
|
* so that in case of an error we can walk down the whole tree again and
|
|
* abort the change.
|
|
*/
|
|
static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
|
|
{
|
|
struct hlist_node *tmp;
|
|
struct clk *child, *fail_clk = NULL;
|
|
int ret = NOTIFY_DONE;
|
|
|
|
if (clk->rate == clk->new_rate)
|
|
return 0;
|
|
|
|
if (clk->notifier_count) {
|
|
ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
|
|
if (ret == NOTIFY_BAD)
|
|
fail_clk = clk;
|
|
}
|
|
|
|
hlist_for_each_entry(child, tmp, &clk->children, child_node) {
|
|
clk = clk_propagate_rate_change(child, event);
|
|
if (clk)
|
|
fail_clk = clk;
|
|
}
|
|
|
|
return fail_clk;
|
|
}
|
|
|
|
/*
|
|
* walk down a subtree and set the new rates notifying the rate
|
|
* change on the way
|
|
*/
|
|
static void clk_change_rate(struct clk *clk)
|
|
{
|
|
struct clk *child;
|
|
unsigned long old_rate;
|
|
unsigned long best_parent_rate = 0;
|
|
struct hlist_node *tmp;
|
|
|
|
old_rate = clk->rate;
|
|
|
|
if (clk->parent)
|
|
best_parent_rate = clk->parent->rate;
|
|
|
|
if (clk->ops->set_rate)
|
|
clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
|
|
|
|
if (clk->ops->recalc_rate)
|
|
clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
|
|
else
|
|
clk->rate = best_parent_rate;
|
|
|
|
if (clk->notifier_count && old_rate != clk->rate)
|
|
__clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
|
|
|
|
hlist_for_each_entry(child, tmp, &clk->children, child_node)
|
|
clk_change_rate(child);
|
|
}
|
|
|
|
/**
|
|
* clk_set_rate - specify a new rate for clk
|
|
* @clk: the clk whose rate is being changed
|
|
* @rate: the new rate for clk
|
|
*
|
|
* In the simplest case clk_set_rate will only adjust the rate of clk.
|
|
*
|
|
* Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
|
|
* propagate up to clk's parent; whether or not this happens depends on the
|
|
* outcome of clk's .round_rate implementation. If *parent_rate is unchanged
|
|
* after calling .round_rate then upstream parent propagation is ignored. If
|
|
* *parent_rate comes back with a new rate for clk's parent then we propagate
|
|
* up to clk's parent and set it's rate. Upward propagation will continue
|
|
* until either a clk does not support the CLK_SET_RATE_PARENT flag or
|
|
* .round_rate stops requesting changes to clk's parent_rate.
|
|
*
|
|
* Rate changes are accomplished via tree traversal that also recalculates the
|
|
* rates for the clocks and fires off POST_RATE_CHANGE notifiers.
|
|
*
|
|
* Returns 0 on success, -EERROR otherwise.
|
|
*/
|
|
int clk_set_rate(struct clk *clk, unsigned long rate)
|
|
{
|
|
struct clk *top, *fail_clk;
|
|
int ret = 0;
|
|
|
|
/* prevent racing with updates to the clock topology */
|
|
mutex_lock(&prepare_lock);
|
|
|
|
/* bail early if nothing to do */
|
|
if (rate == clk->rate)
|
|
goto out;
|
|
|
|
if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
/* calculate new rates and get the topmost changed clock */
|
|
top = clk_calc_new_rates(clk, rate);
|
|
if (!top) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* notify that we are about to change rates */
|
|
fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
|
|
if (fail_clk) {
|
|
pr_warn("%s: failed to set %s rate\n", __func__,
|
|
fail_clk->name);
|
|
clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
/* change the rates */
|
|
clk_change_rate(top);
|
|
|
|
mutex_unlock(&prepare_lock);
|
|
|
|
return 0;
|
|
out:
|
|
mutex_unlock(&prepare_lock);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_set_rate);
|
|
|
|
/**
|
|
* clk_get_parent - return the parent of a clk
|
|
* @clk: the clk whose parent gets returned
|
|
*
|
|
* Simply returns clk->parent. Returns NULL if clk is NULL.
|
|
*/
|
|
struct clk *clk_get_parent(struct clk *clk)
|
|
{
|
|
struct clk *parent;
|
|
|
|
mutex_lock(&prepare_lock);
|
|
parent = __clk_get_parent(clk);
|
|
mutex_unlock(&prepare_lock);
|
|
|
|
return parent;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_get_parent);
|
|
|
|
/*
|
|
* .get_parent is mandatory for clocks with multiple possible parents. It is
|
|
* optional for single-parent clocks. Always call .get_parent if it is
|
|
* available and WARN if it is missing for multi-parent clocks.
|
|
*
|
|
* For single-parent clocks without .get_parent, first check to see if the
|
|
* .parents array exists, and if so use it to avoid an expensive tree
|
|
* traversal. If .parents does not exist then walk the tree with __clk_lookup.
|
|
*/
|
|
static struct clk *__clk_init_parent(struct clk *clk)
|
|
{
|
|
struct clk *ret = NULL;
|
|
u8 index;
|
|
|
|
/* handle the trivial cases */
|
|
|
|
if (!clk->num_parents)
|
|
goto out;
|
|
|
|
if (clk->num_parents == 1) {
|
|
if (IS_ERR_OR_NULL(clk->parent))
|
|
ret = clk->parent = __clk_lookup(clk->parent_names[0]);
|
|
ret = clk->parent;
|
|
goto out;
|
|
}
|
|
|
|
if (!clk->ops->get_parent) {
|
|
WARN(!clk->ops->get_parent,
|
|
"%s: multi-parent clocks must implement .get_parent\n",
|
|
__func__);
|
|
goto out;
|
|
};
|
|
|
|
/*
|
|
* Do our best to cache parent clocks in clk->parents. This prevents
|
|
* unnecessary and expensive calls to __clk_lookup. We don't set
|
|
* clk->parent here; that is done by the calling function
|
|
*/
|
|
|
|
index = clk->ops->get_parent(clk->hw);
|
|
|
|
if (!clk->parents)
|
|
clk->parents =
|
|
kzalloc((sizeof(struct clk*) * clk->num_parents),
|
|
GFP_KERNEL);
|
|
|
|
if (!clk->parents)
|
|
ret = __clk_lookup(clk->parent_names[index]);
|
|
else if (!clk->parents[index])
|
|
ret = clk->parents[index] =
|
|
__clk_lookup(clk->parent_names[index]);
|
|
else
|
|
ret = clk->parents[index];
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
void __clk_reparent(struct clk *clk, struct clk *new_parent)
|
|
{
|
|
#ifdef CONFIG_COMMON_CLK_DEBUG
|
|
struct dentry *d;
|
|
struct dentry *new_parent_d;
|
|
#endif
|
|
|
|
if (!clk || !new_parent)
|
|
return;
|
|
|
|
hlist_del(&clk->child_node);
|
|
|
|
if (new_parent)
|
|
hlist_add_head(&clk->child_node, &new_parent->children);
|
|
else
|
|
hlist_add_head(&clk->child_node, &clk_orphan_list);
|
|
|
|
#ifdef CONFIG_COMMON_CLK_DEBUG
|
|
if (!inited)
|
|
goto out;
|
|
|
|
if (new_parent)
|
|
new_parent_d = new_parent->dentry;
|
|
else
|
|
new_parent_d = orphandir;
|
|
|
|
d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
|
|
new_parent_d, clk->name);
|
|
if (d)
|
|
clk->dentry = d;
|
|
else
|
|
pr_debug("%s: failed to rename debugfs entry for %s\n",
|
|
__func__, clk->name);
|
|
out:
|
|
#endif
|
|
|
|
clk->parent = new_parent;
|
|
|
|
__clk_recalc_rates(clk, POST_RATE_CHANGE);
|
|
}
|
|
|
|
static int __clk_set_parent(struct clk *clk, struct clk *parent)
|
|
{
|
|
struct clk *old_parent;
|
|
unsigned long flags;
|
|
int ret = -EINVAL;
|
|
u8 i;
|
|
|
|
old_parent = clk->parent;
|
|
|
|
/* find index of new parent clock using cached parent ptrs */
|
|
if (clk->parents)
|
|
for (i = 0; i < clk->num_parents; i++)
|
|
if (clk->parents[i] == parent)
|
|
break;
|
|
else
|
|
clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
|
|
GFP_KERNEL);
|
|
|
|
/*
|
|
* find index of new parent clock using string name comparison
|
|
* also try to cache the parent to avoid future calls to __clk_lookup
|
|
*/
|
|
if (i == clk->num_parents)
|
|
for (i = 0; i < clk->num_parents; i++)
|
|
if (!strcmp(clk->parent_names[i], parent->name)) {
|
|
if (clk->parents)
|
|
clk->parents[i] = __clk_lookup(parent->name);
|
|
break;
|
|
}
|
|
|
|
if (i == clk->num_parents) {
|
|
pr_debug("%s: clock %s is not a possible parent of clock %s\n",
|
|
__func__, parent->name, clk->name);
|
|
goto out;
|
|
}
|
|
|
|
/* migrate prepare and enable */
|
|
if (clk->prepare_count)
|
|
__clk_prepare(parent);
|
|
|
|
/* FIXME replace with clk_is_enabled(clk) someday */
|
|
spin_lock_irqsave(&enable_lock, flags);
|
|
if (clk->enable_count)
|
|
__clk_enable(parent);
|
|
spin_unlock_irqrestore(&enable_lock, flags);
|
|
|
|
/* change clock input source */
|
|
ret = clk->ops->set_parent(clk->hw, i);
|
|
|
|
/* clean up old prepare and enable */
|
|
spin_lock_irqsave(&enable_lock, flags);
|
|
if (clk->enable_count)
|
|
__clk_disable(old_parent);
|
|
spin_unlock_irqrestore(&enable_lock, flags);
|
|
|
|
if (clk->prepare_count)
|
|
__clk_unprepare(old_parent);
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* clk_set_parent - switch the parent of a mux clk
|
|
* @clk: the mux clk whose input we are switching
|
|
* @parent: the new input to clk
|
|
*
|
|
* Re-parent clk to use parent as it's new input source. If clk has the
|
|
* CLK_SET_PARENT_GATE flag set then clk must be gated for this
|
|
* operation to succeed. After successfully changing clk's parent
|
|
* clk_set_parent will update the clk topology, sysfs topology and
|
|
* propagate rate recalculation via __clk_recalc_rates. Returns 0 on
|
|
* success, -EERROR otherwise.
|
|
*/
|
|
int clk_set_parent(struct clk *clk, struct clk *parent)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (!clk || !clk->ops)
|
|
return -EINVAL;
|
|
|
|
if (!clk->ops->set_parent)
|
|
return -ENOSYS;
|
|
|
|
/* prevent racing with updates to the clock topology */
|
|
mutex_lock(&prepare_lock);
|
|
|
|
if (clk->parent == parent)
|
|
goto out;
|
|
|
|
/* propagate PRE_RATE_CHANGE notifications */
|
|
if (clk->notifier_count)
|
|
ret = __clk_speculate_rates(clk, parent->rate);
|
|
|
|
/* abort if a driver objects */
|
|
if (ret == NOTIFY_STOP)
|
|
goto out;
|
|
|
|
/* only re-parent if the clock is not in use */
|
|
if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count)
|
|
ret = -EBUSY;
|
|
else
|
|
ret = __clk_set_parent(clk, parent);
|
|
|
|
/* propagate ABORT_RATE_CHANGE if .set_parent failed */
|
|
if (ret) {
|
|
__clk_recalc_rates(clk, ABORT_RATE_CHANGE);
|
|
goto out;
|
|
}
|
|
|
|
/* propagate rate recalculation downstream */
|
|
__clk_reparent(clk, parent);
|
|
|
|
out:
|
|
mutex_unlock(&prepare_lock);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_set_parent);
|
|
|
|
/**
|
|
* __clk_init - initialize the data structures in a struct clk
|
|
* @dev: device initializing this clk, placeholder for now
|
|
* @clk: clk being initialized
|
|
*
|
|
* Initializes the lists in struct clk, queries the hardware for the
|
|
* parent and rate and sets them both.
|
|
*/
|
|
int __clk_init(struct device *dev, struct clk *clk)
|
|
{
|
|
int i, ret = 0;
|
|
struct clk *orphan;
|
|
struct hlist_node *tmp, *tmp2;
|
|
|
|
if (!clk)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&prepare_lock);
|
|
|
|
/* check to see if a clock with this name is already registered */
|
|
if (__clk_lookup(clk->name)) {
|
|
pr_debug("%s: clk %s already initialized\n",
|
|
__func__, clk->name);
|
|
ret = -EEXIST;
|
|
goto out;
|
|
}
|
|
|
|
/* check that clk_ops are sane. See Documentation/clk.txt */
|
|
if (clk->ops->set_rate &&
|
|
!(clk->ops->round_rate && clk->ops->recalc_rate)) {
|
|
pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
|
|
__func__, clk->name);
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (clk->ops->set_parent && !clk->ops->get_parent) {
|
|
pr_warning("%s: %s must implement .get_parent & .set_parent\n",
|
|
__func__, clk->name);
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* throw a WARN if any entries in parent_names are NULL */
|
|
for (i = 0; i < clk->num_parents; i++)
|
|
WARN(!clk->parent_names[i],
|
|
"%s: invalid NULL in %s's .parent_names\n",
|
|
__func__, clk->name);
|
|
|
|
/*
|
|
* Allocate an array of struct clk *'s to avoid unnecessary string
|
|
* look-ups of clk's possible parents. This can fail for clocks passed
|
|
* in to clk_init during early boot; thus any access to clk->parents[]
|
|
* must always check for a NULL pointer and try to populate it if
|
|
* necessary.
|
|
*
|
|
* If clk->parents is not NULL we skip this entire block. This allows
|
|
* for clock drivers to statically initialize clk->parents.
|
|
*/
|
|
if (clk->num_parents && !clk->parents) {
|
|
clk->parents = kmalloc((sizeof(struct clk*) * clk->num_parents),
|
|
GFP_KERNEL);
|
|
/*
|
|
* __clk_lookup returns NULL for parents that have not been
|
|
* clk_init'd; thus any access to clk->parents[] must check
|
|
* for a NULL pointer. We can always perform lazy lookups for
|
|
* missing parents later on.
|
|
*/
|
|
if (clk->parents)
|
|
for (i = 0; i < clk->num_parents; i++)
|
|
clk->parents[i] =
|
|
__clk_lookup(clk->parent_names[i]);
|
|
}
|
|
|
|
clk->parent = __clk_init_parent(clk);
|
|
|
|
/*
|
|
* Populate clk->parent if parent has already been __clk_init'd. If
|
|
* parent has not yet been __clk_init'd then place clk in the orphan
|
|
* list. If clk has set the CLK_IS_ROOT flag then place it in the root
|
|
* clk list.
|
|
*
|
|
* Every time a new clk is clk_init'd then we walk the list of orphan
|
|
* clocks and re-parent any that are children of the clock currently
|
|
* being clk_init'd.
|
|
*/
|
|
if (clk->parent)
|
|
hlist_add_head(&clk->child_node,
|
|
&clk->parent->children);
|
|
else if (clk->flags & CLK_IS_ROOT)
|
|
hlist_add_head(&clk->child_node, &clk_root_list);
|
|
else
|
|
hlist_add_head(&clk->child_node, &clk_orphan_list);
|
|
|
|
/*
|
|
* Set clk's rate. The preferred method is to use .recalc_rate. For
|
|
* simple clocks and lazy developers the default fallback is to use the
|
|
* parent's rate. If a clock doesn't have a parent (or is orphaned)
|
|
* then rate is set to zero.
|
|
*/
|
|
if (clk->ops->recalc_rate)
|
|
clk->rate = clk->ops->recalc_rate(clk->hw,
|
|
__clk_get_rate(clk->parent));
|
|
else if (clk->parent)
|
|
clk->rate = clk->parent->rate;
|
|
else
|
|
clk->rate = 0;
|
|
|
|
/*
|
|
* walk the list of orphan clocks and reparent any that are children of
|
|
* this clock
|
|
*/
|
|
hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node)
|
|
for (i = 0; i < orphan->num_parents; i++)
|
|
if (!strcmp(clk->name, orphan->parent_names[i])) {
|
|
__clk_reparent(orphan, clk);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* optional platform-specific magic
|
|
*
|
|
* The .init callback is not used by any of the basic clock types, but
|
|
* exists for weird hardware that must perform initialization magic.
|
|
* Please consider other ways of solving initialization problems before
|
|
* using this callback, as it's use is discouraged.
|
|
*/
|
|
if (clk->ops->init)
|
|
clk->ops->init(clk->hw);
|
|
|
|
clk_debug_register(clk);
|
|
|
|
out:
|
|
mutex_unlock(&prepare_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* __clk_register - register a clock and return a cookie.
|
|
*
|
|
* Same as clk_register, except that the .clk field inside hw shall point to a
|
|
* preallocated (generally statically allocated) struct clk. None of the fields
|
|
* of the struct clk need to be initialized.
|
|
*
|
|
* The data pointed to by .init and .clk field shall NOT be marked as init
|
|
* data.
|
|
*
|
|
* __clk_register is only exposed via clk-private.h and is intended for use with
|
|
* very large numbers of clocks that need to be statically initialized. It is
|
|
* a layering violation to include clk-private.h from any code which implements
|
|
* a clock's .ops; as such any statically initialized clock data MUST be in a
|
|
* separate C file from the logic that implements it's operations. Returns 0
|
|
* on success, otherwise an error code.
|
|
*/
|
|
struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
|
|
{
|
|
int ret;
|
|
struct clk *clk;
|
|
|
|
clk = hw->clk;
|
|
clk->name = hw->init->name;
|
|
clk->ops = hw->init->ops;
|
|
clk->hw = hw;
|
|
clk->flags = hw->init->flags;
|
|
clk->parent_names = hw->init->parent_names;
|
|
clk->num_parents = hw->init->num_parents;
|
|
|
|
ret = __clk_init(dev, clk);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
return clk;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__clk_register);
|
|
|
|
/**
|
|
* clk_register - allocate a new clock, register it and return an opaque cookie
|
|
* @dev: device that is registering this clock
|
|
* @hw: link to hardware-specific clock data
|
|
*
|
|
* clk_register is the primary interface for populating the clock tree with new
|
|
* clock nodes. It returns a pointer to the newly allocated struct clk which
|
|
* cannot be dereferenced by driver code but may be used in conjuction with the
|
|
* rest of the clock API. In the event of an error clk_register will return an
|
|
* error code; drivers must test for an error code after calling clk_register.
|
|
*/
|
|
struct clk *clk_register(struct device *dev, struct clk_hw *hw)
|
|
{
|
|
int i, ret;
|
|
struct clk *clk;
|
|
|
|
clk = kzalloc(sizeof(*clk), GFP_KERNEL);
|
|
if (!clk) {
|
|
pr_err("%s: could not allocate clk\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto fail_out;
|
|
}
|
|
|
|
clk->name = kstrdup(hw->init->name, GFP_KERNEL);
|
|
if (!clk->name) {
|
|
pr_err("%s: could not allocate clk->name\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto fail_name;
|
|
}
|
|
clk->ops = hw->init->ops;
|
|
clk->hw = hw;
|
|
clk->flags = hw->init->flags;
|
|
clk->num_parents = hw->init->num_parents;
|
|
hw->clk = clk;
|
|
|
|
/* allocate local copy in case parent_names is __initdata */
|
|
clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents),
|
|
GFP_KERNEL);
|
|
|
|
if (!clk->parent_names) {
|
|
pr_err("%s: could not allocate clk->parent_names\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto fail_parent_names;
|
|
}
|
|
|
|
|
|
/* copy each string name in case parent_names is __initdata */
|
|
for (i = 0; i < clk->num_parents; i++) {
|
|
clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
|
|
GFP_KERNEL);
|
|
if (!clk->parent_names[i]) {
|
|
pr_err("%s: could not copy parent_names\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto fail_parent_names_copy;
|
|
}
|
|
}
|
|
|
|
ret = __clk_init(dev, clk);
|
|
if (!ret)
|
|
return clk;
|
|
|
|
fail_parent_names_copy:
|
|
while (--i >= 0)
|
|
kfree(clk->parent_names[i]);
|
|
kfree(clk->parent_names);
|
|
fail_parent_names:
|
|
kfree(clk->name);
|
|
fail_name:
|
|
kfree(clk);
|
|
fail_out:
|
|
return ERR_PTR(ret);
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_register);
|
|
|
|
/**
|
|
* clk_unregister - unregister a currently registered clock
|
|
* @clk: clock to unregister
|
|
*
|
|
* Currently unimplemented.
|
|
*/
|
|
void clk_unregister(struct clk *clk) {}
|
|
EXPORT_SYMBOL_GPL(clk_unregister);
|
|
|
|
/*** clk rate change notifiers ***/
|
|
|
|
/**
|
|
* clk_notifier_register - add a clk rate change notifier
|
|
* @clk: struct clk * to watch
|
|
* @nb: struct notifier_block * with callback info
|
|
*
|
|
* Request notification when clk's rate changes. This uses an SRCU
|
|
* notifier because we want it to block and notifier unregistrations are
|
|
* uncommon. The callbacks associated with the notifier must not
|
|
* re-enter into the clk framework by calling any top-level clk APIs;
|
|
* this will cause a nested prepare_lock mutex.
|
|
*
|
|
* Pre-change notifier callbacks will be passed the current, pre-change
|
|
* rate of the clk via struct clk_notifier_data.old_rate. The new,
|
|
* post-change rate of the clk is passed via struct
|
|
* clk_notifier_data.new_rate.
|
|
*
|
|
* Post-change notifiers will pass the now-current, post-change rate of
|
|
* the clk in both struct clk_notifier_data.old_rate and struct
|
|
* clk_notifier_data.new_rate.
|
|
*
|
|
* Abort-change notifiers are effectively the opposite of pre-change
|
|
* notifiers: the original pre-change clk rate is passed in via struct
|
|
* clk_notifier_data.new_rate and the failed post-change rate is passed
|
|
* in via struct clk_notifier_data.old_rate.
|
|
*
|
|
* clk_notifier_register() must be called from non-atomic context.
|
|
* Returns -EINVAL if called with null arguments, -ENOMEM upon
|
|
* allocation failure; otherwise, passes along the return value of
|
|
* srcu_notifier_chain_register().
|
|
*/
|
|
int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
|
|
{
|
|
struct clk_notifier *cn;
|
|
int ret = -ENOMEM;
|
|
|
|
if (!clk || !nb)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&prepare_lock);
|
|
|
|
/* search the list of notifiers for this clk */
|
|
list_for_each_entry(cn, &clk_notifier_list, node)
|
|
if (cn->clk == clk)
|
|
break;
|
|
|
|
/* if clk wasn't in the notifier list, allocate new clk_notifier */
|
|
if (cn->clk != clk) {
|
|
cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
|
|
if (!cn)
|
|
goto out;
|
|
|
|
cn->clk = clk;
|
|
srcu_init_notifier_head(&cn->notifier_head);
|
|
|
|
list_add(&cn->node, &clk_notifier_list);
|
|
}
|
|
|
|
ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
|
|
|
|
clk->notifier_count++;
|
|
|
|
out:
|
|
mutex_unlock(&prepare_lock);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_notifier_register);
|
|
|
|
/**
|
|
* clk_notifier_unregister - remove a clk rate change notifier
|
|
* @clk: struct clk *
|
|
* @nb: struct notifier_block * with callback info
|
|
*
|
|
* Request no further notification for changes to 'clk' and frees memory
|
|
* allocated in clk_notifier_register.
|
|
*
|
|
* Returns -EINVAL if called with null arguments; otherwise, passes
|
|
* along the return value of srcu_notifier_chain_unregister().
|
|
*/
|
|
int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
|
|
{
|
|
struct clk_notifier *cn = NULL;
|
|
int ret = -EINVAL;
|
|
|
|
if (!clk || !nb)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&prepare_lock);
|
|
|
|
list_for_each_entry(cn, &clk_notifier_list, node)
|
|
if (cn->clk == clk)
|
|
break;
|
|
|
|
if (cn->clk == clk) {
|
|
ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
|
|
|
|
clk->notifier_count--;
|
|
|
|
/* XXX the notifier code should handle this better */
|
|
if (!cn->notifier_head.head) {
|
|
srcu_cleanup_notifier_head(&cn->notifier_head);
|
|
kfree(cn);
|
|
}
|
|
|
|
} else {
|
|
ret = -ENOENT;
|
|
}
|
|
|
|
mutex_unlock(&prepare_lock);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(clk_notifier_unregister);
|