arch/sh/kernel/cpu/clock.c - maze/linux - Git at Google

 /*
  * arch/sh/kernel/cpu/clock.c - SuperH clock framework
  *
  *  Copyright (C) 2005 - 2009  Paul Mundt
  *
  * This clock framework is derived from the OMAP version by:
  *
  *	Copyright (C) 2004 - 2008 Nokia Corporation
  *	Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
  *
  *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
  *
  *  With clkdev bits:
  *
  *	Copyright (C) 2008 Russell King.
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  */
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/list.h>
 #include <linux/kobject.h>
 #include <linux/sysdev.h>
 #include <linux/seq_file.h>
 #include <linux/err.h>
 #include <linux/platform_device.h>
 #include <linux/debugfs.h>
 #include <linux/cpufreq.h>
 #include <asm/clock.h>
 #include <asm/machvec.h>

 static LIST_HEAD(clock_list);
 static DEFINE_SPINLOCK(clock_lock);
 static DEFINE_MUTEX(clock_list_sem);

 void clk_rate_table_build(struct clk *clk,
 			  struct cpufreq_frequency_table *freq_table,
 			  int nr_freqs,
 			  struct clk_div_mult_table *src_table,
 			  unsigned long *bitmap)
 {
 	unsigned long mult, div;
 	unsigned long freq;
 	int i;

 	for (i = 0; i < nr_freqs; i++) {
 		div = 1;
 		mult = 1;

 		if (src_table->divisors && i < src_table->nr_divisors)
 			div = src_table->divisors[i];

 		if (src_table->multipliers && i < src_table->nr_multipliers)
 			mult = src_table->multipliers[i];

 		if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
 			freq = CPUFREQ_ENTRY_INVALID;
 		else
 			freq = clk->parent->rate * mult / div;

 		freq_table[i].index = i;
 		freq_table[i].frequency = freq;
 	}

 	/* Termination entry */
 	freq_table[i].index = i;
 	freq_table[i].frequency = CPUFREQ_TABLE_END;
 }

 long clk_rate_table_round(struct clk *clk,
 			  struct cpufreq_frequency_table *freq_table,
 			  unsigned long rate)
 {
 	unsigned long rate_error, rate_error_prev = ~0UL;
 	unsigned long rate_best_fit = rate;
 	unsigned long highest, lowest;
 	int i;

 	highest = lowest = 0;

 	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 		unsigned long freq = freq_table[i].frequency;

 		if (freq == CPUFREQ_ENTRY_INVALID)
 			continue;

 		if (freq > highest)
 			highest = freq;
 		if (freq < lowest)
 			lowest = freq;

 		rate_error = abs(freq - rate);
 		if (rate_error < rate_error_prev) {
 			rate_best_fit = freq;
 			rate_error_prev = rate_error;
 		}

 		if (rate_error == 0)
 			break;
 	}

 	if (rate >= highest)
 		rate_best_fit = highest;
 	if (rate <= lowest)
 		rate_best_fit = lowest;

 	return rate_best_fit;
 }

 int clk_rate_table_find(struct clk *clk,
 			struct cpufreq_frequency_table *freq_table,
 			unsigned long rate)
 {
 	int i;

 	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 		unsigned long freq = freq_table[i].frequency;

 		if (freq == CPUFREQ_ENTRY_INVALID)
 			continue;

 		if (freq == rate)
 			return i;
 	}

 	return -ENOENT;
 }

 /* Used for clocks that always have same value as the parent clock */
 unsigned long followparent_recalc(struct clk *clk)
 {
 	return clk->parent ? clk->parent->rate : 0;
 }

 int clk_reparent(struct clk *child, struct clk *parent)
 {
 	list_del_init(&child->sibling);
 	if (parent)
 		list_add(&child->sibling, &parent->children);
 	child->parent = parent;

 	/* now do the debugfs renaming to reattach the child
 	   to the proper parent */

 	return 0;
 }

 /* Propagate rate to children */
 void propagate_rate(struct clk *tclk)
 {
 	struct clk *clkp;

 	list_for_each_entry(clkp, &tclk->children, sibling) {
 		if (clkp->ops && clkp->ops->recalc)
 			clkp->rate = clkp->ops->recalc(clkp);

 		propagate_rate(clkp);
 	}
 }

 static void __clk_disable(struct clk *clk)
 {
 	if (clk->usecount == 0) {
 		printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
 		       clk->name);
 		WARN_ON(1);
 		return;
 	}

 	if (!(--clk->usecount)) {
 		if (likely(clk->ops && clk->ops->disable))
 			clk->ops->disable(clk);
 		if (likely(clk->parent))
 			__clk_disable(clk->parent);
 	}
 }

 void clk_disable(struct clk *clk)
 {
 	unsigned long flags;

 	if (!clk)
 		return;

 	spin_lock_irqsave(&clock_lock, flags);
 	__clk_disable(clk);
 	spin_unlock_irqrestore(&clock_lock, flags);
 }
 EXPORT_SYMBOL_GPL(clk_disable);

 static int __clk_enable(struct clk *clk)
 {
 	int ret = 0;

 	if (clk->usecount++ == 0) {
 		if (clk->parent) {
 			ret = __clk_enable(clk->parent);
 			if (unlikely(ret))
 				goto err;
 		}

 		if (clk->ops && clk->ops->enable) {
 			ret = clk->ops->enable(clk);
 			if (ret) {
 				if (clk->parent)
 					__clk_disable(clk->parent);
 				goto err;
 			}
 		}
 	}

 	return ret;
 err:
 	clk->usecount--;
 	return ret;
 }

 int clk_enable(struct clk *clk)
 {
 	unsigned long flags;
 	int ret;

 	if (!clk)
 		return -EINVAL;

 	spin_lock_irqsave(&clock_lock, flags);
 	ret = __clk_enable(clk);
 	spin_unlock_irqrestore(&clock_lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(clk_enable);

 static LIST_HEAD(root_clks);

 /**
  * recalculate_root_clocks - recalculate and propagate all root clocks
  *
  * Recalculates all root clocks (clocks with no parent), which if the
  * clock's .recalc is set correctly, should also propagate their rates.
  * Called at init.
  */
 void recalculate_root_clocks(void)
 {
 	struct clk *clkp;

 	list_for_each_entry(clkp, &root_clks, sibling) {
 		if (clkp->ops && clkp->ops->recalc)
 			clkp->rate = clkp->ops->recalc(clkp);
 		propagate_rate(clkp);
 	}
 }

 int clk_register(struct clk *clk)
 {
 	if (clk == NULL || IS_ERR(clk))
 		return -EINVAL;

 	/*
 	 * trap out already registered clocks
 	 */
 	if (clk->node.next || clk->node.prev)
 		return 0;

 	mutex_lock(&clock_list_sem);

 	INIT_LIST_HEAD(&clk->children);
 	clk->usecount = 0;

 	if (clk->parent)
 		list_add(&clk->sibling, &clk->parent->children);
 	else
 		list_add(&clk->sibling, &root_clks);

 	list_add(&clk->node, &clock_list);
 	if (clk->ops && clk->ops->init)
 		clk->ops->init(clk);
 	mutex_unlock(&clock_list_sem);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(clk_register);

 void clk_unregister(struct clk *clk)
 {
 	mutex_lock(&clock_list_sem);
 	list_del(&clk->sibling);
 	list_del(&clk->node);
 	mutex_unlock(&clock_list_sem);
 }
 EXPORT_SYMBOL_GPL(clk_unregister);

 static void clk_enable_init_clocks(void)
 {
 	struct clk *clkp;

 	list_for_each_entry(clkp, &clock_list, node)
 		if (clkp->flags & CLK_ENABLE_ON_INIT)
 			clk_enable(clkp);
 }

 unsigned long clk_get_rate(struct clk *clk)
 {
 	return clk->rate;
 }
 EXPORT_SYMBOL_GPL(clk_get_rate);

 int clk_set_rate(struct clk *clk, unsigned long rate)
 {
 	return clk_set_rate_ex(clk, rate, 0);
 }
 EXPORT_SYMBOL_GPL(clk_set_rate);

 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 {
 	int ret = -EOPNOTSUPP;
 	unsigned long flags;

 	spin_lock_irqsave(&clock_lock, flags);

 	if (likely(clk->ops && clk->ops->set_rate)) {
 		ret = clk->ops->set_rate(clk, rate, algo_id);
 		if (ret != 0)
 			goto out_unlock;
 	} else {
 		clk->rate = rate;
 		ret = 0;
 	}

 	if (clk->ops && clk->ops->recalc)
 		clk->rate = clk->ops->recalc(clk);

 	propagate_rate(clk);

 out_unlock:
 	spin_unlock_irqrestore(&clock_lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(clk_set_rate_ex);

 int clk_set_parent(struct clk *clk, struct clk *parent)
 {
 	unsigned long flags;
 	int ret = -EINVAL;

 	if (!parent || !clk)
 		return ret;
 	if (clk->parent == parent)
 		return 0;

 	spin_lock_irqsave(&clock_lock, flags);
 	if (clk->usecount == 0) {
 		if (clk->ops->set_parent)
 			ret = clk->ops->set_parent(clk, parent);
 		else
 			ret = clk_reparent(clk, parent);

 		if (ret == 0) {
 			pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
 				 clk->name, clk->parent->name, clk->rate);
 			if (clk->ops->recalc)
 				clk->rate = clk->ops->recalc(clk);
 			propagate_rate(clk);
 		}
 	} else
 		ret = -EBUSY;
 	spin_unlock_irqrestore(&clock_lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(clk_set_parent);

 struct clk *clk_get_parent(struct clk *clk)
 {
 	return clk->parent;
 }
 EXPORT_SYMBOL_GPL(clk_get_parent);

 long clk_round_rate(struct clk *clk, unsigned long rate)
 {
 	if (likely(clk->ops && clk->ops->round_rate)) {
 		unsigned long flags, rounded;

 		spin_lock_irqsave(&clock_lock, flags);
 		rounded = clk->ops->round_rate(clk, rate);
 		spin_unlock_irqrestore(&clock_lock, flags);

 		return rounded;
 	}

 	return clk_get_rate(clk);
 }
 EXPORT_SYMBOL_GPL(clk_round_rate);

 /*
  * Find the correct struct clk for the device and connection ID.
  * We do slightly fuzzy matching here:
  *  An entry with a NULL ID is assumed to be a wildcard.
  *  If an entry has a device ID, it must match
  *  If an entry has a connection ID, it must match
  * Then we take the most specific entry - with the following
  * order of precedence: dev+con > dev only > con only.
  */
 static struct clk *clk_find(const char *dev_id, const char *con_id)
 {
 	struct clk_lookup *p;
 	struct clk *clk = NULL;
 	int match, best = 0;

 	list_for_each_entry(p, &clock_list, node) {
 		match = 0;
 		if (p->dev_id) {
 			if (!dev_id || strcmp(p->dev_id, dev_id))
 				continue;
 			match += 2;
 		}
 		if (p->con_id) {
 			if (!con_id || strcmp(p->con_id, con_id))
 				continue;
 			match += 1;
 		}
 		if (match == 0)
 			continue;

 		if (match > best) {
 			clk = p->clk;
 			best = match;
 		}
 	}
 	return clk;
 }

 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
 {
 	struct clk *clk;

 	mutex_lock(&clock_list_sem);
 	clk = clk_find(dev_id, con_id);
 	mutex_unlock(&clock_list_sem);

 	return clk ? clk : ERR_PTR(-ENOENT);
 }
 EXPORT_SYMBOL_GPL(clk_get_sys);

 /*
  * Returns a clock. Note that we first try to use device id on the bus
  * and clock name. If this fails, we try to use clock name only.
  */
 struct clk *clk_get(struct device *dev, const char *id)
 {
 	const char *dev_id = dev ? dev_name(dev) : NULL;
 	struct clk *p, *clk = ERR_PTR(-ENOENT);
 	int idno;

 	clk = clk_get_sys(dev_id, id);
 	if (clk && !IS_ERR(clk))
 		return clk;

 	if (dev == NULL || dev->bus != &platform_bus_type)
 		idno = -1;
 	else
 		idno = to_platform_device(dev)->id;

 	mutex_lock(&clock_list_sem);
 	list_for_each_entry(p, &clock_list, node) {
 		if (p->id == idno &&
 		    strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 			clk = p;
 			goto found;
 		}
 	}

 	list_for_each_entry(p, &clock_list, node) {
 		if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 			clk = p;
 			break;
 		}
 	}

 found:
 	mutex_unlock(&clock_list_sem);

 	return clk;
 }
 EXPORT_SYMBOL_GPL(clk_get);

 void clk_put(struct clk *clk)
 {
 	if (clk && !IS_ERR(clk))
 		module_put(clk->owner);
 }
 EXPORT_SYMBOL_GPL(clk_put);

 #ifdef CONFIG_PM
 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 {
 	static pm_message_t prev_state;
 	struct clk *clkp;

 	switch (state.event) {
 	case PM_EVENT_ON:
 		/* Resumeing from hibernation */
 		if (prev_state.event != PM_EVENT_FREEZE)
 			break;

 		list_for_each_entry(clkp, &clock_list, node) {
 			if (likely(clkp->ops)) {
 				unsigned long rate = clkp->rate;

 				if (likely(clkp->ops->set_parent))
 					clkp->ops->set_parent(clkp,
 						clkp->parent);
 				if (likely(clkp->ops->set_rate))
 					clkp->ops->set_rate(clkp,
 						rate, NO_CHANGE);
 				else if (likely(clkp->ops->recalc))
 					clkp->rate = clkp->ops->recalc(clkp);
 			}
 		}
 		break;
 	case PM_EVENT_FREEZE:
 		break;
 	case PM_EVENT_SUSPEND:
 		break;
 	}

 	prev_state = state;
 	return 0;
 }

 static int clks_sysdev_resume(struct sys_device *dev)
 {
 	return clks_sysdev_suspend(dev, PMSG_ON);
 }

 static struct sysdev_class clks_sysdev_class = {
 	.name = "clks",
 };

 static struct sysdev_driver clks_sysdev_driver = {
 	.suspend = clks_sysdev_suspend,
 	.resume = clks_sysdev_resume,
 };

 static struct sys_device clks_sysdev_dev = {
 	.cls = &clks_sysdev_class,
 };

 static int __init clk_sysdev_init(void)
 {
 	sysdev_class_register(&clks_sysdev_class);
 	sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
 	sysdev_register(&clks_sysdev_dev);

 	return 0;
 }
 subsys_initcall(clk_sysdev_init);
 #endif

 int __init clk_init(void)
 {
 	int ret;

 	ret = arch_clk_init();
 	if (unlikely(ret)) {
 		pr_err("%s: CPU clock registration failed.\n", __func__);
 		return ret;
 	}

 	if (sh_mv.mv_clk_init) {
 		ret = sh_mv.mv_clk_init();
 		if (unlikely(ret)) {
 			pr_err("%s: machvec clock initialization failed.\n",
 			       __func__);
 			return ret;
 		}
 	}

 	/* Kick the child clocks.. */
 	recalculate_root_clocks();

 	/* Enable the necessary init clocks */
 	clk_enable_init_clocks();

 	return ret;
 }

 /*
  *	debugfs support to trace clock tree hierarchy and attributes
  */
 static struct dentry *clk_debugfs_root;

 static int clk_debugfs_register_one(struct clk *c)
 {
 	int err;
 	struct dentry *d, *child, *child_tmp;
 	struct clk *pa = c->parent;
 	char s[255];
 	char *p = s;

 	p += sprintf(p, "%s", c->name);
 	if (c->id >= 0)
 		sprintf(p, ":%d", c->id);
 	d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
 	if (!d)
 		return -ENOMEM;
 	c->dentry = d;

 	d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
 	if (!d) {
 		err = -ENOMEM;
 		goto err_out;
 	}
 	d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
 	if (!d) {
 		err = -ENOMEM;
 		goto err_out;
 	}
 	d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
 	if (!d) {
 		err = -ENOMEM;
 		goto err_out;
 	}
 	return 0;

 err_out:
 	d = c->dentry;
 	list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 		debugfs_remove(child);
 	debugfs_remove(c->dentry);
 	return err;
 }

 static int clk_debugfs_register(struct clk *c)
 {
 	int err;
 	struct clk *pa = c->parent;

 	if (pa && !pa->dentry) {
 		err = clk_debugfs_register(pa);
 		if (err)
 			return err;
 	}

 	if (!c->dentry) {
 		err = clk_debugfs_register_one(c);
 		if (err)
 			return err;
 	}
 	return 0;
 }

 static int __init clk_debugfs_init(void)
 {
 	struct clk *c;
 	struct dentry *d;
 	int err;

 	d = debugfs_create_dir("clock", NULL);
 	if (!d)
 		return -ENOMEM;
 	clk_debugfs_root = d;

 	list_for_each_entry(c, &clock_list, node) {
 		err = clk_debugfs_register(c);
 		if (err)
 			goto err_out;
 	}
 	return 0;
 err_out:
 	debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
 	return err;
 }
 late_initcall(clk_debugfs_init);
	/*
	* arch/sh/kernel/cpu/clock.c - SuperH clock framework
	*
	* Copyright (C) 2005 - 2009 Paul Mundt
	*
	* This clock framework is derived from the OMAP version by:
	*
	* Copyright (C) 2004 - 2008 Nokia Corporation
	* Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
	*
	* Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
	*
	* With clkdev bits:
	*
	* Copyright (C) 2008 Russell King.
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*/
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/list.h>
	#include <linux/kobject.h>
	#include <linux/sysdev.h>
	#include <linux/seq_file.h>
	#include <linux/err.h>
	#include <linux/platform_device.h>
	#include <linux/debugfs.h>
	#include <linux/cpufreq.h>
	#include <asm/clock.h>
	#include <asm/machvec.h>

	static LIST_HEAD(clock_list);
	static DEFINE_SPINLOCK(clock_lock);
	static DEFINE_MUTEX(clock_list_sem);

	void clk_rate_table_build(struct clk *clk,
	struct cpufreq_frequency_table *freq_table,
	int nr_freqs,
	struct clk_div_mult_table *src_table,
	unsigned long *bitmap)
	{
	unsigned long mult, div;
	unsigned long freq;
	int i;

	for (i = 0; i < nr_freqs; i++) {
	div = 1;
	mult = 1;

	if (src_table->divisors && i < src_table->nr_divisors)
	div = src_table->divisors[i];

	if (src_table->multipliers && i < src_table->nr_multipliers)
	mult = src_table->multipliers[i];

	if (!div \|\| !mult \|\| (bitmap && !test_bit(i, bitmap)))
	freq = CPUFREQ_ENTRY_INVALID;
	else
	freq = clk->parent->rate * mult / div;

	freq_table[i].index = i;
	freq_table[i].frequency = freq;
	}

	/* Termination entry */
	freq_table[i].index = i;
	freq_table[i].frequency = CPUFREQ_TABLE_END;
	}

	long clk_rate_table_round(struct clk *clk,
	struct cpufreq_frequency_table *freq_table,
	unsigned long rate)
	{
	unsigned long rate_error, rate_error_prev = ~0UL;
	unsigned long rate_best_fit = rate;
	unsigned long highest, lowest;
	int i;

	highest = lowest = 0;

	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
	unsigned long freq = freq_table[i].frequency;

	if (freq == CPUFREQ_ENTRY_INVALID)
	continue;

	if (freq > highest)
	highest = freq;
	if (freq < lowest)
	lowest = freq;

	rate_error = abs(freq - rate);
	if (rate_error < rate_error_prev) {
	rate_best_fit = freq;
	rate_error_prev = rate_error;
	}

	if (rate_error == 0)
	break;
	}

	if (rate >= highest)
	rate_best_fit = highest;
	if (rate <= lowest)
	rate_best_fit = lowest;

	return rate_best_fit;
	}

	int clk_rate_table_find(struct clk *clk,
	struct cpufreq_frequency_table *freq_table,
	unsigned long rate)
	{
	int i;

	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
	unsigned long freq = freq_table[i].frequency;

	if (freq == CPUFREQ_ENTRY_INVALID)
	continue;

	if (freq == rate)
	return i;
	}

	return -ENOENT;
	}

	/* Used for clocks that always have same value as the parent clock */
	unsigned long followparent_recalc(struct clk *clk)
	{
	return clk->parent ? clk->parent->rate : 0;
	}

	int clk_reparent(struct clk child, struct clk parent)
	{
	list_del_init(&child->sibling);
	if (parent)
	list_add(&child->sibling, &parent->children);
	child->parent = parent;

	/* now do the debugfs renaming to reattach the child
	to the proper parent */

	return 0;
	}

	/* Propagate rate to children */
	void propagate_rate(struct clk *tclk)
	{
	struct clk *clkp;

	list_for_each_entry(clkp, &tclk->children, sibling) {
	if (clkp->ops && clkp->ops->recalc)
	clkp->rate = clkp->ops->recalc(clkp);

	propagate_rate(clkp);
	}
	}

	static void __clk_disable(struct clk *clk)
	{
	if (clk->usecount == 0) {
	printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
	clk->name);
	WARN_ON(1);
	return;
	}

	if (!(--clk->usecount)) {
	if (likely(clk->ops && clk->ops->disable))
	clk->ops->disable(clk);
	if (likely(clk->parent))
	__clk_disable(clk->parent);
	}
	}

	void clk_disable(struct clk *clk)
	{
	unsigned long flags;

	if (!clk)
	return;

	spin_lock_irqsave(&clock_lock, flags);
	__clk_disable(clk);
	spin_unlock_irqrestore(&clock_lock, flags);
	}
	EXPORT_SYMBOL_GPL(clk_disable);

	static int __clk_enable(struct clk *clk)
	{
	int ret = 0;

	if (clk->usecount++ == 0) {
	if (clk->parent) {
	ret = __clk_enable(clk->parent);
	if (unlikely(ret))
	goto err;
	}

	if (clk->ops && clk->ops->enable) {
	ret = clk->ops->enable(clk);
	if (ret) {
	if (clk->parent)
	__clk_disable(clk->parent);
	goto err;
	}
	}
	}

	return ret;
	err:
	clk->usecount--;
	return ret;
	}

	int clk_enable(struct clk *clk)
	{
	unsigned long flags;
	int ret;

	if (!clk)
	return -EINVAL;

	spin_lock_irqsave(&clock_lock, flags);
	ret = __clk_enable(clk);
	spin_unlock_irqrestore(&clock_lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(clk_enable);

	static LIST_HEAD(root_clks);

	/**
	* recalculate_root_clocks - recalculate and propagate all root clocks
	*
	* Recalculates all root clocks (clocks with no parent), which if the
	* clock's .recalc is set correctly, should also propagate their rates.
	* Called at init.
	*/
	void recalculate_root_clocks(void)
	{
	struct clk *clkp;

	list_for_each_entry(clkp, &root_clks, sibling) {
	if (clkp->ops && clkp->ops->recalc)
	clkp->rate = clkp->ops->recalc(clkp);
	propagate_rate(clkp);
	}
	}

	int clk_register(struct clk *clk)
	{
	if (clk == NULL \|\| IS_ERR(clk))
	return -EINVAL;

	/*
	* trap out already registered clocks
	*/
	if (clk->node.next \|\| clk->node.prev)
	return 0;

	mutex_lock(&clock_list_sem);

	INIT_LIST_HEAD(&clk->children);
	clk->usecount = 0;

	if (clk->parent)
	list_add(&clk->sibling, &clk->parent->children);
	else
	list_add(&clk->sibling, &root_clks);

	list_add(&clk->node, &clock_list);
	if (clk->ops && clk->ops->init)
	clk->ops->init(clk);
	mutex_unlock(&clock_list_sem);

	return 0;
	}
	EXPORT_SYMBOL_GPL(clk_register);

	void clk_unregister(struct clk *clk)
	{
	mutex_lock(&clock_list_sem);
	list_del(&clk->sibling);
	list_del(&clk->node);
	mutex_unlock(&clock_list_sem);
	}
	EXPORT_SYMBOL_GPL(clk_unregister);

	static void clk_enable_init_clocks(void)
	{
	struct clk *clkp;

	list_for_each_entry(clkp, &clock_list, node)
	if (clkp->flags & CLK_ENABLE_ON_INIT)
	clk_enable(clkp);
	}

	unsigned long clk_get_rate(struct clk *clk)
	{
	return clk->rate;
	}
	EXPORT_SYMBOL_GPL(clk_get_rate);

	int clk_set_rate(struct clk *clk, unsigned long rate)
	{
	return clk_set_rate_ex(clk, rate, 0);
	}
	EXPORT_SYMBOL_GPL(clk_set_rate);

	int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
	{
	int ret = -EOPNOTSUPP;
	unsigned long flags;

	spin_lock_irqsave(&clock_lock, flags);

	if (likely(clk->ops && clk->ops->set_rate)) {
	ret = clk->ops->set_rate(clk, rate, algo_id);
	if (ret != 0)
	goto out_unlock;
	} else {
	clk->rate = rate;
	ret = 0;
	}

	if (clk->ops && clk->ops->recalc)
	clk->rate = clk->ops->recalc(clk);

	propagate_rate(clk);

	out_unlock:
	spin_unlock_irqrestore(&clock_lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(clk_set_rate_ex);

	int clk_set_parent(struct clk clk, struct clk parent)
	{
	unsigned long flags;
	int ret = -EINVAL;

	if (!parent \|\| !clk)
	return ret;
	if (clk->parent == parent)
	return 0;

	spin_lock_irqsave(&clock_lock, flags);
	if (clk->usecount == 0) {
	if (clk->ops->set_parent)
	ret = clk->ops->set_parent(clk, parent);
	else
	ret = clk_reparent(clk, parent);

	if (ret == 0) {
	pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
	clk->name, clk->parent->name, clk->rate);
	if (clk->ops->recalc)
	clk->rate = clk->ops->recalc(clk);
	propagate_rate(clk);
	}
	} else
	ret = -EBUSY;
	spin_unlock_irqrestore(&clock_lock, flags);

	return ret;
	}
	EXPORT_SYMBOL_GPL(clk_set_parent);

	struct clk clk_get_parent(struct clk clk)
	{
	return clk->parent;
	}
	EXPORT_SYMBOL_GPL(clk_get_parent);

	long clk_round_rate(struct clk *clk, unsigned long rate)
	{
	if (likely(clk->ops && clk->ops->round_rate)) {
	unsigned long flags, rounded;

	spin_lock_irqsave(&clock_lock, flags);
	rounded = clk->ops->round_rate(clk, rate);
	spin_unlock_irqrestore(&clock_lock, flags);

	return rounded;
	}

	return clk_get_rate(clk);
	}
	EXPORT_SYMBOL_GPL(clk_round_rate);

	/*
	* Find the correct struct clk for the device and connection ID.
	* We do slightly fuzzy matching here:
	* An entry with a NULL ID is assumed to be a wildcard.
	* If an entry has a device ID, it must match
	* If an entry has a connection ID, it must match
	* Then we take the most specific entry - with the following
	* order of precedence: dev+con > dev only > con only.
	*/
	static struct clk clk_find(const char dev_id, const char *con_id)
	{
	struct clk_lookup *p;
	struct clk *clk = NULL;
	int match, best = 0;

	list_for_each_entry(p, &clock_list, node) {
	match = 0;
	if (p->dev_id) {
	if (!dev_id \|\| strcmp(p->dev_id, dev_id))
	continue;
	match += 2;
	}
	if (p->con_id) {
	if (!con_id \|\| strcmp(p->con_id, con_id))
	continue;
	match += 1;
	}
	if (match == 0)
	continue;

	if (match > best) {
	clk = p->clk;
	best = match;
	}
	}
	return clk;
	}

	struct clk clk_get_sys(const char dev_id, const char *con_id)
	{
	struct clk *clk;

	mutex_lock(&clock_list_sem);
	clk = clk_find(dev_id, con_id);
	mutex_unlock(&clock_list_sem);

	return clk ? clk : ERR_PTR(-ENOENT);
	}
	EXPORT_SYMBOL_GPL(clk_get_sys);

	/*
	* Returns a clock. Note that we first try to use device id on the bus
	* and clock name. If this fails, we try to use clock name only.
	*/
	struct clk clk_get(struct device dev, const char *id)
	{
	const char *dev_id = dev ? dev_name(dev) : NULL;
	struct clk p, clk = ERR_PTR(-ENOENT);
	int idno;

	clk = clk_get_sys(dev_id, id);
	if (clk && !IS_ERR(clk))
	return clk;

	if (dev == NULL \|\| dev->bus != &platform_bus_type)
	idno = -1;
	else
	idno = to_platform_device(dev)->id;

	mutex_lock(&clock_list_sem);
	list_for_each_entry(p, &clock_list, node) {
	if (p->id == idno &&
	strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
	clk = p;
	goto found;
	}
	}

	list_for_each_entry(p, &clock_list, node) {
	if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
	clk = p;
	break;
	}
	}

	found:
	mutex_unlock(&clock_list_sem);

	return clk;
	}
	EXPORT_SYMBOL_GPL(clk_get);

	void clk_put(struct clk *clk)
	{
	if (clk && !IS_ERR(clk))
	module_put(clk->owner);
	}
	EXPORT_SYMBOL_GPL(clk_put);

	#ifdef CONFIG_PM
	static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
	{
	static pm_message_t prev_state;
	struct clk *clkp;

	switch (state.event) {
	case PM_EVENT_ON:
	/* Resumeing from hibernation */
	if (prev_state.event != PM_EVENT_FREEZE)
	break;

	list_for_each_entry(clkp, &clock_list, node) {
	if (likely(clkp->ops)) {
	unsigned long rate = clkp->rate;

	if (likely(clkp->ops->set_parent))
	clkp->ops->set_parent(clkp,
	clkp->parent);
	if (likely(clkp->ops->set_rate))
	clkp->ops->set_rate(clkp,
	rate, NO_CHANGE);
	else if (likely(clkp->ops->recalc))
	clkp->rate = clkp->ops->recalc(clkp);
	}
	}
	break;
	case PM_EVENT_FREEZE:
	break;
	case PM_EVENT_SUSPEND:
	break;
	}

	prev_state = state;
	return 0;
	}

	static int clks_sysdev_resume(struct sys_device *dev)
	{
	return clks_sysdev_suspend(dev, PMSG_ON);
	}

	static struct sysdev_class clks_sysdev_class = {
	.name = "clks",
	};

	static struct sysdev_driver clks_sysdev_driver = {
	.suspend = clks_sysdev_suspend,
	.resume = clks_sysdev_resume,
	};

	static struct sys_device clks_sysdev_dev = {
	.cls = &clks_sysdev_class,
	};

	static int __init clk_sysdev_init(void)
	{
	sysdev_class_register(&clks_sysdev_class);
	sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
	sysdev_register(&clks_sysdev_dev);

	return 0;
	}
	subsys_initcall(clk_sysdev_init);
	#endif

	int __init clk_init(void)
	{
	int ret;

	ret = arch_clk_init();
	if (unlikely(ret)) {
	pr_err("%s: CPU clock registration failed.\n", __func__);
	return ret;
	}

	if (sh_mv.mv_clk_init) {
	ret = sh_mv.mv_clk_init();
	if (unlikely(ret)) {
	pr_err("%s: machvec clock initialization failed.\n",
	__func__);
	return ret;
	}
	}

	/* Kick the child clocks.. */
	recalculate_root_clocks();

	/* Enable the necessary init clocks */
	clk_enable_init_clocks();

	return ret;
	}

	/*
	* debugfs support to trace clock tree hierarchy and attributes
	*/
	static struct dentry *clk_debugfs_root;

	static int clk_debugfs_register_one(struct clk *c)
	{
	int err;
	struct dentry d, child, *child_tmp;
	struct clk *pa = c->parent;
	char s[255];
	char *p = s;

	p += sprintf(p, "%s", c->name);
	if (c->id >= 0)
	sprintf(p, ":%d", c->id);
	d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
	if (!d)
	return -ENOMEM;
	c->dentry = d;

	d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
	if (!d) {
	err = -ENOMEM;
	goto err_out;
	}
	d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
	if (!d) {
	err = -ENOMEM;
	goto err_out;
	}
	d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
	if (!d) {
	err = -ENOMEM;
	goto err_out;
	}
	return 0;

	err_out:
	d = c->dentry;
	list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
	debugfs_remove(child);
	debugfs_remove(c->dentry);
	return err;
	}

	static int clk_debugfs_register(struct clk *c)
	{
	int err;
	struct clk *pa = c->parent;

	if (pa && !pa->dentry) {
	err = clk_debugfs_register(pa);
	if (err)
	return err;
	}

	if (!c->dentry) {
	err = clk_debugfs_register_one(c);
	if (err)
	return err;
	}
	return 0;
	}

	static int __init clk_debugfs_init(void)
	{
	struct clk *c;
	struct dentry *d;
	int err;

	d = debugfs_create_dir("clock", NULL);
	if (!d)
	return -ENOMEM;
	clk_debugfs_root = d;

	list_for_each_entry(c, &clock_list, node) {
	err = clk_debugfs_register(c);
	if (err)
	goto err_out;
	}
	return 0;
	err_out:
	debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
	return err;
	}
	late_initcall(clk_debugfs_init);