drivers/clk/clkdev.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * drivers/clk/clkdev.c
  *
  *  Copyright (C) 2008 Russell King.
  *
  * Helper for the clk API to assist looking up a struct clk.
  */
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
 #include <linux/list.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/string.h>
 #include <linux/mutex.h>
 #include <linux/clk.h>
 #include <linux/clkdev.h>
 #include <linux/clk-provider.h>
 #include <linux/of.h>

 #include "clk.h"

 static LIST_HEAD(clocks);
 static DEFINE_MUTEX(clocks_mutex);

 /*
  * 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_lookup *clk_find(const char *dev_id, const char *con_id)
 {
 	struct clk_lookup *p, *cl = NULL;
 	int match, best_found = 0, best_possible = 0;

 	if (dev_id)
 		best_possible += 2;
 	if (con_id)
 		best_possible += 1;

 	lockdep_assert_held(&clocks_mutex);

 	list_for_each_entry(p, &clocks, 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 > best_found) {
 			cl = p;
 			if (match != best_possible)
 				best_found = match;
 			else
 				break;
 		}
 	}
 	return cl;
 }

 struct clk_hw *clk_find_hw(const char *dev_id, const char *con_id)
 {
 	struct clk_lookup *cl;
 	struct clk_hw *hw = ERR_PTR(-ENOENT);

 	mutex_lock(&clocks_mutex);
 	cl = clk_find(dev_id, con_id);
 	if (cl)
 		hw = cl->clk_hw;
 	mutex_unlock(&clocks_mutex);

 	return hw;
 }

 static struct clk *__clk_get_sys(struct device *dev, const char *dev_id,
 				 const char *con_id)
 {
 	struct clk_hw *hw = clk_find_hw(dev_id, con_id);

 	return clk_hw_create_clk(dev, hw, dev_id, con_id);
 }

 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
 {
 	return __clk_get_sys(NULL, dev_id, con_id);
 }
 EXPORT_SYMBOL(clk_get_sys);

 struct clk *clk_get(struct device *dev, const char *con_id)
 {
 	const char *dev_id = dev ? dev_name(dev) : NULL;
 	struct clk_hw *hw;

 	if (dev && dev->of_node) {
 		hw = of_clk_get_hw(dev->of_node, 0, con_id);
 		if (!IS_ERR(hw) || PTR_ERR(hw) == -EPROBE_DEFER)
 			return clk_hw_create_clk(dev, hw, dev_id, con_id);
 	}

 	return __clk_get_sys(dev, dev_id, con_id);
 }
 EXPORT_SYMBOL(clk_get);

 void clk_put(struct clk *clk)
 {
 	__clk_put(clk);
 }
 EXPORT_SYMBOL(clk_put);

 static void __clkdev_add(struct clk_lookup *cl)
 {
 	mutex_lock(&clocks_mutex);
 	list_add_tail(&cl->node, &clocks);
 	mutex_unlock(&clocks_mutex);
 }

 void clkdev_add(struct clk_lookup *cl)
 {
 	if (!cl->clk_hw)
 		cl->clk_hw = __clk_get_hw(cl->clk);
 	__clkdev_add(cl);
 }
 EXPORT_SYMBOL(clkdev_add);

 void clkdev_add_table(struct clk_lookup *cl, size_t num)
 {
 	mutex_lock(&clocks_mutex);
 	while (num--) {
 		cl->clk_hw = __clk_get_hw(cl->clk);
 		list_add_tail(&cl->node, &clocks);
 		cl++;
 	}
 	mutex_unlock(&clocks_mutex);
 }

 #define MAX_DEV_ID	20
 #define MAX_CON_ID	16

 struct clk_lookup_alloc {
 	struct clk_lookup cl;
 	char	dev_id[MAX_DEV_ID];
 	char	con_id[MAX_CON_ID];
 };

 static struct clk_lookup * __ref
 vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
 	va_list ap)
 {
 	struct clk_lookup_alloc *cla;

 	cla = kzalloc(sizeof(*cla), GFP_KERNEL);
 	if (!cla)
 		return NULL;

 	cla->cl.clk_hw = hw;
 	if (con_id) {
 		strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
 		cla->cl.con_id = cla->con_id;
 	}

 	if (dev_fmt) {
 		vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
 		cla->cl.dev_id = cla->dev_id;
 	}

 	return &cla->cl;
 }

 static struct clk_lookup *
 vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
 	va_list ap)
 {
 	struct clk_lookup *cl;

 	cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
 	if (cl)
 		__clkdev_add(cl);

 	return cl;
 }

 struct clk_lookup * __ref
 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
 {
 	struct clk_lookup *cl;
 	va_list ap;

 	va_start(ap, dev_fmt);
 	cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap);
 	va_end(ap);

 	return cl;
 }
 EXPORT_SYMBOL(clkdev_alloc);

 struct clk_lookup *
 clkdev_hw_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, ...)
 {
 	struct clk_lookup *cl;
 	va_list ap;

 	va_start(ap, dev_fmt);
 	cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
 	va_end(ap);

 	return cl;
 }
 EXPORT_SYMBOL(clkdev_hw_alloc);

 /**
  * clkdev_create - allocate and add a clkdev lookup structure
  * @clk: struct clk to associate with all clk_lookups
  * @con_id: connection ID string on device
  * @dev_fmt: format string describing device name
  *
  * Returns a clk_lookup structure, which can be later unregistered and
  * freed.
  */
 struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id,
 	const char *dev_fmt, ...)
 {
 	struct clk_lookup *cl;
 	va_list ap;

 	va_start(ap, dev_fmt);
 	cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap);
 	va_end(ap);

 	return cl;
 }
 EXPORT_SYMBOL_GPL(clkdev_create);

 /**
  * clkdev_hw_create - allocate and add a clkdev lookup structure
  * @hw: struct clk_hw to associate with all clk_lookups
  * @con_id: connection ID string on device
  * @dev_fmt: format string describing device name
  *
  * Returns a clk_lookup structure, which can be later unregistered and
  * freed.
  */
 struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id,
 	const char *dev_fmt, ...)
 {
 	struct clk_lookup *cl;
 	va_list ap;

 	va_start(ap, dev_fmt);
 	cl = vclkdev_create(hw, con_id, dev_fmt, ap);
 	va_end(ap);

 	return cl;
 }
 EXPORT_SYMBOL_GPL(clkdev_hw_create);

 int clk_add_alias(const char *alias, const char *alias_dev_name,
 	const char *con_id, struct device *dev)
 {
 	struct clk *r = clk_get(dev, con_id);
 	struct clk_lookup *l;

 	if (IS_ERR(r))
 		return PTR_ERR(r);

 	l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL,
 			  alias_dev_name);
 	clk_put(r);

 	return l ? 0 : -ENODEV;
 }
 EXPORT_SYMBOL(clk_add_alias);

 /*
  * clkdev_drop - remove a clock dynamically allocated
  */
 void clkdev_drop(struct clk_lookup *cl)
 {
 	mutex_lock(&clocks_mutex);
 	list_del(&cl->node);
 	mutex_unlock(&clocks_mutex);
 	kfree(cl);
 }
 EXPORT_SYMBOL(clkdev_drop);

 static struct clk_lookup *__clk_register_clkdev(struct clk_hw *hw,
 						const char *con_id,
 						const char *dev_id, ...)
 {
 	struct clk_lookup *cl;
 	va_list ap;

 	va_start(ap, dev_id);
 	cl = vclkdev_create(hw, con_id, dev_id, ap);
 	va_end(ap);

 	return cl;
 }

 static int do_clk_register_clkdev(struct clk_hw *hw,
 	struct clk_lookup **cl, const char *con_id, const char *dev_id)
 {
 	if (IS_ERR(hw))
 		return PTR_ERR(hw);
 	/*
 	 * Since dev_id can be NULL, and NULL is handled specially, we must
 	 * pass it as either a NULL format string, or with "%s".
 	 */
 	if (dev_id)
 		*cl = __clk_register_clkdev(hw, con_id, "%s", dev_id);
 	else
 		*cl = __clk_register_clkdev(hw, con_id, NULL);

 	return *cl ? 0 : -ENOMEM;
 }

 /**
  * clk_register_clkdev - register one clock lookup for a struct clk
  * @clk: struct clk to associate with all clk_lookups
  * @con_id: connection ID string on device
  * @dev_id: string describing device name
  *
  * con_id or dev_id may be NULL as a wildcard, just as in the rest of
  * clkdev.
  *
  * To make things easier for mass registration, we detect error clks
  * from a previous clk_register() call, and return the error code for
  * those.  This is to permit this function to be called immediately
  * after clk_register().
  */
 int clk_register_clkdev(struct clk *clk, const char *con_id,
 	const char *dev_id)
 {
 	struct clk_lookup *cl;

 	if (IS_ERR(clk))
 		return PTR_ERR(clk);

 	return do_clk_register_clkdev(__clk_get_hw(clk), &cl, con_id,
 					      dev_id);
 }
 EXPORT_SYMBOL(clk_register_clkdev);

 /**
  * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw
  * @hw: struct clk_hw to associate with all clk_lookups
  * @con_id: connection ID string on device
  * @dev_id: format string describing device name
  *
  * con_id or dev_id may be NULL as a wildcard, just as in the rest of
  * clkdev.
  *
  * To make things easier for mass registration, we detect error clk_hws
  * from a previous clk_hw_register_*() call, and return the error code for
  * those.  This is to permit this function to be called immediately
  * after clk_hw_register_*().
  */
 int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id,
 	const char *dev_id)
 {
 	struct clk_lookup *cl;

 	return do_clk_register_clkdev(hw, &cl, con_id, dev_id);
 }
 EXPORT_SYMBOL(clk_hw_register_clkdev);

 static void devm_clkdev_release(struct device *dev, void *res)
 {
 	clkdev_drop(*(struct clk_lookup **)res);
 }

 static int devm_clk_match_clkdev(struct device *dev, void *res, void *data)
 {
 	struct clk_lookup **l = res;

 	return *l == data;
 }

 /**
  * devm_clk_release_clkdev - Resource managed clkdev lookup release
  * @dev: device this lookup is bound
  * @con_id: connection ID string on device
  * @dev_id: format string describing device name
  *
  * Drop the clkdev lookup created with devm_clk_hw_register_clkdev.
  * Normally this function will not need to be called and the resource
  * management code will ensure that the resource is freed.
  */
 void devm_clk_release_clkdev(struct device *dev, const char *con_id,
 			     const char *dev_id)
 {
 	struct clk_lookup *cl;
 	int rval;

 	mutex_lock(&clocks_mutex);
 	cl = clk_find(dev_id, con_id);
 	mutex_unlock(&clocks_mutex);

 	WARN_ON(!cl);
 	rval = devres_release(dev, devm_clkdev_release,
 			      devm_clk_match_clkdev, cl);
 	WARN_ON(rval);
 }
 EXPORT_SYMBOL(devm_clk_release_clkdev);

 /**
  * devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw
  * @dev: device this lookup is bound
  * @hw: struct clk_hw to associate with all clk_lookups
  * @con_id: connection ID string on device
  * @dev_id: format string describing device name
  *
  * con_id or dev_id may be NULL as a wildcard, just as in the rest of
  * clkdev.
  *
  * To make things easier for mass registration, we detect error clk_hws
  * from a previous clk_hw_register_*() call, and return the error code for
  * those.  This is to permit this function to be called immediately
  * after clk_hw_register_*().
  */
 int devm_clk_hw_register_clkdev(struct device *dev, struct clk_hw *hw,
 				const char *con_id, const char *dev_id)
 {
 	int rval = -ENOMEM;
 	struct clk_lookup **cl;

 	cl = devres_alloc(devm_clkdev_release, sizeof(*cl), GFP_KERNEL);
 	if (cl) {
 		rval = do_clk_register_clkdev(hw, cl, con_id, dev_id);
 		if (!rval)
 			devres_add(dev, cl);
 		else
 			devres_free(cl);
 	}
 	return rval;
 }
 EXPORT_SYMBOL(devm_clk_hw_register_clkdev);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* drivers/clk/clkdev.c
	*
	* Copyright (C) 2008 Russell King.
	*
	* Helper for the clk API to assist looking up a struct clk.
	*/
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/device.h>
	#include <linux/list.h>
	#include <linux/errno.h>
	#include <linux/err.h>
	#include <linux/string.h>
	#include <linux/mutex.h>
	#include <linux/clk.h>
	#include <linux/clkdev.h>
	#include <linux/clk-provider.h>
	#include <linux/of.h>

	#include "clk.h"

	static LIST_HEAD(clocks);
	static DEFINE_MUTEX(clocks_mutex);

	/*
	* 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_lookup clk_find(const char dev_id, const char *con_id)
	{
	struct clk_lookup p, cl = NULL;
	int match, best_found = 0, best_possible = 0;

	if (dev_id)
	best_possible += 2;
	if (con_id)
	best_possible += 1;

	lockdep_assert_held(&clocks_mutex);

	list_for_each_entry(p, &clocks, 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 > best_found) {
	cl = p;
	if (match != best_possible)
	best_found = match;
	else
	break;
	}
	}
	return cl;
	}

	struct clk_hw clk_find_hw(const char dev_id, const char *con_id)
	{
	struct clk_lookup *cl;
	struct clk_hw *hw = ERR_PTR(-ENOENT);

	mutex_lock(&clocks_mutex);
	cl = clk_find(dev_id, con_id);
	if (cl)
	hw = cl->clk_hw;
	mutex_unlock(&clocks_mutex);

	return hw;
	}

	static struct clk __clk_get_sys(struct device dev, const char *dev_id,
	const char *con_id)
	{
	struct clk_hw *hw = clk_find_hw(dev_id, con_id);

	return clk_hw_create_clk(dev, hw, dev_id, con_id);
	}

	struct clk clk_get_sys(const char dev_id, const char *con_id)
	{
	return __clk_get_sys(NULL, dev_id, con_id);
	}
	EXPORT_SYMBOL(clk_get_sys);

	struct clk clk_get(struct device dev, const char *con_id)
	{
	const char *dev_id = dev ? dev_name(dev) : NULL;
	struct clk_hw *hw;

	if (dev && dev->of_node) {
	hw = of_clk_get_hw(dev->of_node, 0, con_id);
	if (!IS_ERR(hw) \|\| PTR_ERR(hw) == -EPROBE_DEFER)
	return clk_hw_create_clk(dev, hw, dev_id, con_id);
	}

	return __clk_get_sys(dev, dev_id, con_id);
	}
	EXPORT_SYMBOL(clk_get);

	void clk_put(struct clk *clk)
	{
	__clk_put(clk);
	}
	EXPORT_SYMBOL(clk_put);

	static void __clkdev_add(struct clk_lookup *cl)
	{
	mutex_lock(&clocks_mutex);
	list_add_tail(&cl->node, &clocks);
	mutex_unlock(&clocks_mutex);
	}

	void clkdev_add(struct clk_lookup *cl)
	{
	if (!cl->clk_hw)
	cl->clk_hw = __clk_get_hw(cl->clk);
	__clkdev_add(cl);
	}
	EXPORT_SYMBOL(clkdev_add);

	void clkdev_add_table(struct clk_lookup *cl, size_t num)
	{
	mutex_lock(&clocks_mutex);
	while (num--) {
	cl->clk_hw = __clk_get_hw(cl->clk);
	list_add_tail(&cl->node, &clocks);
	cl++;
	}
	mutex_unlock(&clocks_mutex);
	}

	#define MAX_DEV_ID 20
	#define MAX_CON_ID 16

	struct clk_lookup_alloc {
	struct clk_lookup cl;
	char dev_id[MAX_DEV_ID];
	char con_id[MAX_CON_ID];
	};

	static struct clk_lookup * __ref
	vclkdev_alloc(struct clk_hw hw, const char con_id, const char *dev_fmt,
	va_list ap)
	{
	struct clk_lookup_alloc *cla;

	cla = kzalloc(sizeof(*cla), GFP_KERNEL);
	if (!cla)
	return NULL;

	cla->cl.clk_hw = hw;
	if (con_id) {
	strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
	cla->cl.con_id = cla->con_id;
	}

	if (dev_fmt) {
	vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
	cla->cl.dev_id = cla->dev_id;
	}

	return &cla->cl;
	}

	static struct clk_lookup *
	vclkdev_create(struct clk_hw hw, const char con_id, const char *dev_fmt,
	va_list ap)
	{
	struct clk_lookup *cl;

	cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
	if (cl)
	__clkdev_add(cl);

	return cl;
	}

	struct clk_lookup * __ref
	clkdev_alloc(struct clk clk, const char con_id, const char *dev_fmt, ...)
	{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_fmt);
	cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap);
	va_end(ap);

	return cl;
	}
	EXPORT_SYMBOL(clkdev_alloc);

	struct clk_lookup *
	clkdev_hw_alloc(struct clk_hw hw, const char con_id, const char *dev_fmt, ...)
	{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_fmt);
	cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
	va_end(ap);

	return cl;
	}
	EXPORT_SYMBOL(clkdev_hw_alloc);

	/**
	* clkdev_create - allocate and add a clkdev lookup structure
	* @clk: struct clk to associate with all clk_lookups
	* @con_id: connection ID string on device
	* @dev_fmt: format string describing device name
	*
	* Returns a clk_lookup structure, which can be later unregistered and
	* freed.
	*/
	struct clk_lookup clkdev_create(struct clk clk, const char *con_id,
	const char *dev_fmt, ...)
	{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_fmt);
	cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap);
	va_end(ap);

	return cl;
	}
	EXPORT_SYMBOL_GPL(clkdev_create);

	/**
	* clkdev_hw_create - allocate and add a clkdev lookup structure
	* @hw: struct clk_hw to associate with all clk_lookups
	* @con_id: connection ID string on device
	* @dev_fmt: format string describing device name
	*
	* Returns a clk_lookup structure, which can be later unregistered and
	* freed.
	*/
	struct clk_lookup clkdev_hw_create(struct clk_hw hw, const char *con_id,
	const char *dev_fmt, ...)
	{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_fmt);
	cl = vclkdev_create(hw, con_id, dev_fmt, ap);
	va_end(ap);

	return cl;
	}
	EXPORT_SYMBOL_GPL(clkdev_hw_create);

	int clk_add_alias(const char alias, const char alias_dev_name,
	const char con_id, struct device dev)
	{
	struct clk *r = clk_get(dev, con_id);
	struct clk_lookup *l;

	if (IS_ERR(r))
	return PTR_ERR(r);

	l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL,
	alias_dev_name);
	clk_put(r);

	return l ? 0 : -ENODEV;
	}
	EXPORT_SYMBOL(clk_add_alias);

	/*
	* clkdev_drop - remove a clock dynamically allocated
	*/
	void clkdev_drop(struct clk_lookup *cl)
	{
	mutex_lock(&clocks_mutex);
	list_del(&cl->node);
	mutex_unlock(&clocks_mutex);
	kfree(cl);
	}
	EXPORT_SYMBOL(clkdev_drop);

	static struct clk_lookup __clk_register_clkdev(struct clk_hw hw,
	const char *con_id,
	const char *dev_id, ...)
	{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_id);
	cl = vclkdev_create(hw, con_id, dev_id, ap);
	va_end(ap);

	return cl;
	}

	static int do_clk_register_clkdev(struct clk_hw *hw,
	struct clk_lookup *cl, const char con_id, const char *dev_id)
	{
	if (IS_ERR(hw))
	return PTR_ERR(hw);
	/*
	* Since dev_id can be NULL, and NULL is handled specially, we must
	* pass it as either a NULL format string, or with "%s".
	*/
	if (dev_id)
	*cl = __clk_register_clkdev(hw, con_id, "%s", dev_id);
	else
	*cl = __clk_register_clkdev(hw, con_id, NULL);

	return *cl ? 0 : -ENOMEM;
	}

	/**
	* clk_register_clkdev - register one clock lookup for a struct clk
	* @clk: struct clk to associate with all clk_lookups
	* @con_id: connection ID string on device
	* @dev_id: string describing device name
	*
	* con_id or dev_id may be NULL as a wildcard, just as in the rest of
	* clkdev.
	*
	* To make things easier for mass registration, we detect error clks
	* from a previous clk_register() call, and return the error code for
	* those. This is to permit this function to be called immediately
	* after clk_register().
	*/
	int clk_register_clkdev(struct clk clk, const char con_id,
	const char *dev_id)
	{
	struct clk_lookup *cl;

	if (IS_ERR(clk))
	return PTR_ERR(clk);

	return do_clk_register_clkdev(__clk_get_hw(clk), &cl, con_id,
	dev_id);
	}
	EXPORT_SYMBOL(clk_register_clkdev);

	/**
	* clk_hw_register_clkdev - register one clock lookup for a struct clk_hw
	* @hw: struct clk_hw to associate with all clk_lookups
	* @con_id: connection ID string on device
	* @dev_id: format string describing device name
	*
	* con_id or dev_id may be NULL as a wildcard, just as in the rest of
	* clkdev.
	*
	* To make things easier for mass registration, we detect error clk_hws
	* from a previous clk_hw_register_*() call, and return the error code for
	* those. This is to permit this function to be called immediately
	* after clk_hw_register_*().
	*/
	int clk_hw_register_clkdev(struct clk_hw hw, const char con_id,
	const char *dev_id)
	{
	struct clk_lookup *cl;

	return do_clk_register_clkdev(hw, &cl, con_id, dev_id);
	}
	EXPORT_SYMBOL(clk_hw_register_clkdev);

	static void devm_clkdev_release(struct device dev, void res)
	{
	clkdev_drop((struct clk_lookup *)res);
	}

	static int devm_clk_match_clkdev(struct device dev, void res, void *data)
	{
	struct clk_lookup **l = res;

	return *l == data;
	}

	/**
	* devm_clk_release_clkdev - Resource managed clkdev lookup release
	* @dev: device this lookup is bound
	* @con_id: connection ID string on device
	* @dev_id: format string describing device name
	*
	* Drop the clkdev lookup created with devm_clk_hw_register_clkdev.
	* Normally this function will not need to be called and the resource
	* management code will ensure that the resource is freed.
	*/
	void devm_clk_release_clkdev(struct device dev, const char con_id,
	const char *dev_id)
	{
	struct clk_lookup *cl;
	int rval;

	mutex_lock(&clocks_mutex);
	cl = clk_find(dev_id, con_id);
	mutex_unlock(&clocks_mutex);

	WARN_ON(!cl);
	rval = devres_release(dev, devm_clkdev_release,
	devm_clk_match_clkdev, cl);
	WARN_ON(rval);
	}
	EXPORT_SYMBOL(devm_clk_release_clkdev);

	/**
	* devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw
	* @dev: device this lookup is bound
	* @hw: struct clk_hw to associate with all clk_lookups
	* @con_id: connection ID string on device
	* @dev_id: format string describing device name
	*
	* con_id or dev_id may be NULL as a wildcard, just as in the rest of
	* clkdev.
	*
	* To make things easier for mass registration, we detect error clk_hws
	* from a previous clk_hw_register_*() call, and return the error code for
	* those. This is to permit this function to be called immediately
	* after clk_hw_register_*().
	*/
	int devm_clk_hw_register_clkdev(struct device dev, struct clk_hw hw,
	const char con_id, const char dev_id)
	{
	int rval = -ENOMEM;
	struct clk_lookup **cl;

	cl = devres_alloc(devm_clkdev_release, sizeof(*cl), GFP_KERNEL);
	if (cl) {
	rval = do_clk_register_clkdev(hw, cl, con_id, dev_id);
	if (!rval)
	devres_add(dev, cl);
	else
	devres_free(cl);
	}
	return rval;
	}
	EXPORT_SYMBOL(devm_clk_hw_register_clkdev);