drivers/clk/clk-multiplier.c - kernel/lockdown - Git at Google

 /*
  * Copyright (C) 2015 Jim Quinlan, Broadcom <jim2101024@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * Adjustable multiplier clock implementation.  This is essentially
  * the mirror of clk-divider.c.
  */

 #include <linux/clk-provider.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/err.h>
 #include <linux/string.h>
 #include <linux/log2.h>
 #include <linux/of.h>
 #include <linux/of_address.h>

 /*
  * DOC: basic adjustable multiplier clock that cannot gate
  *
  * Traits of this clock:
  * prepare - clk_prepare only ensures that parents are prepared
  * enable - clk_enable only ensures that parents are enabled
  * rate - rate is adjustable.  clk->rate = (parent->rate * multiplier)
  * parent - fixed parent.  No clk_set_parent support
  */

 #define to_clk_multiplier(_hw) container_of(_hw, struct clk_multiplier, hw)

 #define mult_mask(width)	((1 << (width)) - 1)

 static unsigned int _get_table_minmult(const struct clk_mult_table *table)
 {
 	unsigned int minmult = UINT_MAX;
 	const struct clk_mult_table *clkt;

 	for (clkt = table; clkt->mult; clkt++)
 		if (clkt->mult < minmult)
 			minmult = clkt->mult;
 	return minmult;
 }

 static unsigned int _get_table_maxmult(const struct clk_mult_table *table)
 {
 	unsigned int maxmult = 0;
 	const struct clk_mult_table *clkt;

 	for (clkt = table; clkt->mult; clkt++)
 		if (clkt->mult > maxmult)
 			maxmult = clkt->mult;
 	return maxmult;
 }

 static unsigned int _get_minmult(const struct clk_mult_table *table)
 {
 	if (table)
 		return _get_table_minmult(table);
 	return 1;
 }

 static unsigned int _get_maxmult(const struct clk_mult_table *table, u8 width,
 				unsigned long flags)
 {
 	if (flags & CLK_MULTIPLIER_ONE_BASED)
 		return mult_mask(width);
 	if (flags & CLK_MULTIPLIER_POWER_OF_TWO)
 		return 1 << mult_mask(width);
 	if (table)
 		return _get_table_maxmult(table);
 	return mult_mask(width) + 1;
 }

 static unsigned int _get_table_mult(const struct clk_mult_table *table,
 							unsigned int val)
 {
 	const struct clk_mult_table *clkt;

 	for (clkt = table; clkt->mult; clkt++)
 		if (clkt->val == val)
 			return clkt->mult;
 	return 0;
 }

 static unsigned int _get_mult(const struct clk_mult_table *table,
 			      u8 width, unsigned int val, unsigned long flags)
 {
 	if (flags & CLK_MULTIPLIER_ONE_BASED)
 		return val;
 	if (flags & CLK_MULTIPLIER_POWER_OF_TWO)
 		return 1 << val;
 	if (flags & CLK_MULTIPLIER_MAX_MULT_AT_ZERO)
 		return val ? val : mult_mask(width) + 1;
 	if (table)
 		return _get_table_mult(table, val);
 	return val + 1;
 }

 static unsigned int _get_table_val(const struct clk_mult_table *table,
 				   unsigned int mult)
 {
 	const struct clk_mult_table *clkt;

 	for (clkt = table; clkt->mult; clkt++)
 		if (clkt->mult == mult)
 			return clkt->val;
 	return 0;
 }

 static unsigned int _get_val(const struct clk_mult_table *table,
 			     u8 width, unsigned int mult, unsigned long flags)
 {
 	if (flags & CLK_MULTIPLIER_ONE_BASED)
 		return mult;
 	if (flags & CLK_MULTIPLIER_POWER_OF_TWO)
 		return __ffs(mult);
 	if (flags & CLK_MULTIPLIER_MAX_MULT_AT_ZERO)
 		return (mult == mult_mask(width) + 1)
 			? 0 : mult;
 	if (table)
 		return  _get_table_val(table, mult);
 	return mult - 1;
 }

 unsigned long multiplier_recalc_rate(struct clk_hw *hw,
 				     unsigned long parent_rate,
 				     unsigned int val,
 				     const struct clk_mult_table *table,
 				     unsigned long flags)
 {
 	struct clk_multiplier *multiplier = to_clk_multiplier(hw);
 	unsigned int mult;

 	mult = _get_mult(table, multiplier->width, val, flags);
 	if (!mult) {
 		WARN(!(flags & CLK_MULTIPLIER_ALLOW_ZERO),
 			"%s: Zero multiplier and CLK_MULTIPLIER_ALLOW_ZERO not set\n",
 			__clk_get_name(hw->clk));
 		return parent_rate;
 	}

 	return parent_rate * mult;
 }
 EXPORT_SYMBOL_GPL(multiplier_recalc_rate);

 static unsigned long clk_multiplier_recalc_rate(struct clk_hw *hw,
 		unsigned long parent_rate)
 {
 	struct clk_multiplier *multiplier = to_clk_multiplier(hw);
 	unsigned int val;

 	val = clk_readl(multiplier->reg) >> multiplier->shift;
 	val &= mult_mask(multiplier->width);

 	return multiplier_recalc_rate(hw, parent_rate, val, multiplier->table,
 				   multiplier->flags);
 }

 static bool _is_valid_table_mult(const struct clk_mult_table *table,
 							 unsigned int mult)
 {
 	const struct clk_mult_table *clkt;

 	for (clkt = table; clkt->mult; clkt++)
 		if (clkt->mult == mult)
 			return true;
 	return false;
 }

 static bool _is_valid_mult(const struct clk_mult_table *table,
 			   unsigned int mult, unsigned long flags)
 {
 	if (flags & CLK_MULTIPLIER_POWER_OF_TWO)
 		return is_power_of_2(mult);
 	if (table)
 		return _is_valid_table_mult(table, mult);
 	return true;
 }

 static int clk_multiplier_bestmult(struct clk_hw *hw, unsigned long rate,
 			       unsigned long *best_parent_rate,
 			       const struct clk_mult_table *table, u8 width,
 			       unsigned long flags)
 {
 	int i, bestmult = 0;
 	unsigned long parent_rate, best = 0, now, maxmult, minmult;
 	unsigned long parent_rate_saved = *best_parent_rate;

 	if (!rate)
 		rate = 1;

 	minmult = _get_minmult(table);
 	maxmult = _get_maxmult(table, width, flags);

 	if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
 		parent_rate = *best_parent_rate;
 		bestmult = rate / parent_rate;
 		bestmult = bestmult == 0 ? minmult : bestmult;
 		bestmult = bestmult > maxmult ? maxmult : bestmult;
 		return bestmult;
 	}

 	/*
 	 * The maximum multiplier we can use without overflowing
 	 * unsigned long in rate * i below
 	 */
 	maxmult = min(ULONG_MAX / parent_rate_saved, maxmult);

 	for (i = 1; i <= maxmult; i++) {
 		if (!_is_valid_mult(table, i, flags))
 			continue;
 		if (rate == parent_rate_saved * i) {
 			/*
 			 * It's the most ideal case if the requested rate can be
 			 * multiplied from parent clock without needing to
 			 * change the parent rate, so return the multiplier
 			 * immediately.
 			 */
 			*best_parent_rate = parent_rate_saved;
 			return i;
 		}
 		parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
 					       rate / i);
 		now = parent_rate * i;
 		if (now <= rate && now > best) {
 			bestmult = i;
 			best = now;
 			*best_parent_rate = parent_rate;
 		}
 	}

 	if (!bestmult) {
 		bestmult = _get_minmult(table);
 		*best_parent_rate
 			= __clk_round_rate(__clk_get_parent(hw->clk), 1);
 	}

 	return bestmult;
 }

 long multiplier_round_rate(struct clk_hw *hw, unsigned long rate,
 			   unsigned long *prate,
 			   const struct clk_mult_table *table,
 			   u8 width, unsigned long flags)
 {
 	int mult;

 	mult = clk_multiplier_bestmult(hw, rate, prate, table, width, flags);

 	return *prate * mult;
 }
 EXPORT_SYMBOL_GPL(multiplier_round_rate);

 static long clk_multiplier_round_rate(struct clk_hw *hw, unsigned long rate,
 				unsigned long *prate)
 {
 	struct clk_multiplier *multiplier = to_clk_multiplier(hw);
 	int bestmult;

 	/* if read only, just return current value */
 	if (multiplier->flags & CLK_MULTIPLIER_READ_ONLY) {
 		bestmult = readl(multiplier->reg) >> multiplier->shift;
 		bestmult &= mult_mask(multiplier->width);
 		bestmult = _get_mult(multiplier->table, multiplier->width,
 				     bestmult, multiplier->flags);
 		if ((__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT))
 			*prate = __clk_round_rate(__clk_get_parent(hw->clk),
 						  rate);
 		return *prate * bestmult;
 	}

 	return multiplier_round_rate(hw, rate, prate, multiplier->table,
 				  multiplier->width, multiplier->flags);
 }

 int multiplier_get_val(unsigned long rate, unsigned long parent_rate,
 		    const struct clk_mult_table *table, u8 width,
 		    unsigned long flags)
 {
 	unsigned int mult, value;

 	mult = rate / parent_rate;
 	value = _get_val(table, width, mult, flags);
 	return min_t(unsigned int, value, mult_mask(width));
 }
 EXPORT_SYMBOL_GPL(multiplier_get_val);

 static int clk_multiplier_set_rate(struct clk_hw *hw, unsigned long rate,
 				unsigned long parent_rate)
 {
 	struct clk_multiplier *multiplier = to_clk_multiplier(hw);
 	unsigned int value;
 	unsigned long flags = 0;
 	u32 val;

 	value = multiplier_get_val(rate, parent_rate, multiplier->table,
 				multiplier->width, multiplier->flags);

 	if (multiplier->lock)
 		spin_lock_irqsave(multiplier->lock, flags);

 	if (multiplier->flags & CLK_MULTIPLIER_HIWORD_MASK) {
 		val = mult_mask(multiplier->width) << (multiplier->shift + 16);
 	} else {
 		val = clk_readl(multiplier->reg);
 		val &= ~(mult_mask(multiplier->width) << multiplier->shift);
 	}
 	val |= value << multiplier->shift;
 	clk_writel(val, multiplier->reg);

 	if (multiplier->lock)
 		spin_unlock_irqrestore(multiplier->lock, flags);

 	return 0;
 }

 const struct clk_ops clk_multiplier_ops = {
 	.recalc_rate = clk_multiplier_recalc_rate,
 	.round_rate = clk_multiplier_round_rate,
 	.set_rate = clk_multiplier_set_rate,
 };
 EXPORT_SYMBOL_GPL(clk_multiplier_ops);

 const struct clk_ops clk_multiplier_ro_ops = {
 	.recalc_rate = clk_multiplier_recalc_rate,
 };
 EXPORT_SYMBOL_GPL(clk_multiplier_ro_ops);

 static struct clk *_register_multiplier(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 shift, u8 width,
 		u8 clk_multiplier_flags, const struct clk_mult_table *table,
 		spinlock_t *lock)
 {
 	struct clk_multiplier *mult;
 	struct clk *clk;
 	struct clk_init_data init;

 	if (clk_multiplier_flags & CLK_MULTIPLIER_HIWORD_MASK) {
 		if (width + shift > 16) {
 			pr_warn("multiplier value exceeds LOWORD field\n");
 			return ERR_PTR(-EINVAL);
 		}
 	}

 	/* allocate the multiplier */
 	mult = kzalloc(sizeof(struct clk_multiplier), GFP_KERNEL);
 	if (!mult)
 		return ERR_PTR(-ENOMEM);

 	init.name = name;
 	if (clk_multiplier_flags & CLK_MULTIPLIER_READ_ONLY)
 		init.ops = &clk_multiplier_ro_ops;
 	else
 		init.ops = &clk_multiplier_ops;
 	init.flags = flags | CLK_IS_BASIC;
 	init.parent_names = (parent_name ? &parent_name : NULL);
 	init.num_parents = (parent_name ? 1 : 0);

 	/* struct clk_multiplier assignments */
 	mult->reg = reg;
 	mult->shift = shift;
 	mult->width = width;
 	mult->flags = clk_multiplier_flags;
 	mult->lock = lock;
 	mult->hw.init = &init;
 	mult->table = table;

 	/* register the clock */
 	clk = clk_register(dev, &mult->hw);

 	if (IS_ERR(clk))
 		kfree(mult);

 	return clk;
 }

 /**
  * clk_register_multiplier - register a multiplier clock with the clock framework
  * @dev: device registering this clock
  * @name: name of this clock
  * @parent_name: name of clock's parent
  * @flags: framework-specific flags
  * @reg: register address to adjust multiplier
  * @shift: number of bits to shift the bitfield
  * @width: width of the bitfield
  * @clk_multiplier_flags: multiplier-specific flags for this clock
  * @lock: shared register lock for this clock
  */
 struct clk *clk_register_multiplier(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 shift, u8 width,
 		u8 clk_multiplier_flags, spinlock_t *lock)
 {
 	return _register_multiplier(dev, name, parent_name, flags, reg, shift,
 			width, clk_multiplier_flags, NULL, lock);
 }
 EXPORT_SYMBOL_GPL(clk_register_multiplier);

 /**
  * clk_register_multiplier_table - register a table based multiplier clock with
  * the clock framework
  * @dev: device registering this clock
  * @name: name of this clock
  * @parent_name: name of clock's parent
  * @flags: framework-specific flags
  * @reg: register address to adjust multiplier
  * @shift: number of bits to shift the bitfield
  * @width: width of the bitfield
  * @clk_multiplier_flags: multiplier-specific flags for this clock
  * @table: array of multiplier/value pairs ending with a mult set to 0
  * @lock: shared register lock for this clock
  */
 struct clk *clk_register_multiplier_table(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 shift, u8 width,
 		u8 clk_multiplier_flags, const struct clk_mult_table *table,
 		spinlock_t *lock)
 {
 	return _register_multiplier(dev, name, parent_name, flags, reg, shift,
 			width, clk_multiplier_flags, table, lock);
 }
 EXPORT_SYMBOL_GPL(clk_register_multiplier_table);

 void clk_unregister_multiplier(struct clk *clk)
 {
 	struct clk_multiplier *mult;
 	struct clk_hw *hw;

 	hw = __clk_get_hw(clk);
 	if (!hw)
 		return;

 	mult = to_clk_multiplier(hw);

 	clk_unregister(clk);
 	kfree(mult);
 }
 EXPORT_SYMBOL_GPL(clk_unregister_multiplier);

 #ifdef CONFIG_OF
 static struct clk_mult_table *of_clk_get_mult_table(struct device_node *node)
 {
 	int i;
 	unsigned int table_size;
 	struct clk_mult_table *table;
 	const __be32 *tablespec;
 	u32 val;

 	tablespec = of_get_property(node, "table", (int *) &table_size);

 	if (!tablespec)
 		return NULL;

 	table_size /= sizeof(struct clk_mult_table);

 	if (!table_size) {
 		pr_err("%s: %s table has zero length\n", __func__,
 		       node->name);
 		return ERR_PTR(-EINVAL);
 	}

 	table = kzalloc(sizeof(struct clk_mult_table) * (table_size + 1),
 			GFP_KERNEL);
 	if (!table) {
 		pr_err("%s: unable to allocate memory for %s table\n", __func__,
 		       node->name);
 		return NULL;
 	}

 	for (i = 0; i < table_size; i++) {
 		of_property_read_u32_index(node, "table", i * 2, &val);
 		table[i].mult = val;
 		of_property_read_u32_index(node, "table", i * 2 + 1, &val);
 		table[i].val = val;
 	}

 	return table;
 }

 /**
  * of_multiplier_clk_setup() - Setup function for simple mult rate clock
  */
 void of_multiplier_clk_setup(struct device_node *node)
 {
 	struct clk *clk;
 	const char *clk_name = node->name;
 	void __iomem *reg;
 	const char *parent_name;
 	u8 clk_multiplier_flags = 0;
 	u32 mask = 0;
 	u32 shift = 0;
 	u32 width;
 	struct clk_mult_table *table;

 	of_property_read_string(node, "clock-output-names", &clk_name);

 	parent_name = of_clk_get_parent_name(node, 0);

 	reg = of_iomap(node, 0);
 	if (!reg) {
 		pr_err("%s: no memory mapped for property reg\n", __func__);
 		return;
 	}

 	if (of_property_read_u32(node, "bit-mask", &mask)) {
 		pr_err("%s: missing bit-mask property for %s\n", __func__,
 		       node->name);
 		return;
 	}
 	width = fls(mask);
 	if ((1 << width) - 1 != mask) {
 		pr_err("%s: bad bit-mask for %s\n", __func__, node->name);
 		return;
 	}

 	if (of_property_read_u32(node, "bit-shift", &shift)) {
 		shift = __ffs(mask);
 		pr_debug("%s: bit-shift property defaults to 0x%x for %s\n",
 				__func__, shift, node->name);
 	}

 	if (of_property_read_bool(node, "index-starts-at-one"))
 		clk_multiplier_flags |= CLK_MULTIPLIER_ONE_BASED;

 	if (of_property_read_bool(node, "index-power-of-two"))
 		clk_multiplier_flags |= CLK_MULTIPLIER_POWER_OF_TWO;

 	if (of_property_read_bool(node, "index-allow-zero"))
 		clk_multiplier_flags |= CLK_MULTIPLIER_ALLOW_ZERO;

 	if (of_property_read_bool(node, "index-max-mult-at-zero"))
 		clk_multiplier_flags |= CLK_MULTIPLIER_MAX_MULT_AT_ZERO;

 	table = of_clk_get_mult_table(node);
 	if (IS_ERR(table))
 		return;

 	clk = _register_multiplier(NULL, clk_name, parent_name, 0, reg, shift,
 			width, clk_multiplier_flags, table, NULL);

 	if (!IS_ERR(clk))
 		of_clk_add_provider(node, of_clk_src_simple_get, clk);
 }
 EXPORT_SYMBOL_GPL(of_multiplier_clk_setup);
 CLK_OF_DECLARE(multiplier_clk, "multiplier-clock", of_multiplier_clk_setup);
 #endif
	/*
	* Copyright (C) 2015 Jim Quinlan, Broadcom <jim2101024@gmail.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* Adjustable multiplier clock implementation. This is essentially
	* the mirror of clk-divider.c.
	*/

	#include <linux/clk-provider.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/io.h>
	#include <linux/err.h>
	#include <linux/string.h>
	#include <linux/log2.h>
	#include <linux/of.h>
	#include <linux/of_address.h>

	/*
	* DOC: basic adjustable multiplier clock that cannot gate
	*
	* Traits of this clock:
	* prepare - clk_prepare only ensures that parents are prepared
	* enable - clk_enable only ensures that parents are enabled
	* rate - rate is adjustable. clk->rate = (parent->rate * multiplier)
	* parent - fixed parent. No clk_set_parent support
	*/

	#define to_clk_multiplier(_hw) container_of(_hw, struct clk_multiplier, hw)

	#define mult_mask(width) ((1 << (width)) - 1)

	static unsigned int _get_table_minmult(const struct clk_mult_table *table)
	{
	unsigned int minmult = UINT_MAX;
	const struct clk_mult_table *clkt;

	for (clkt = table; clkt->mult; clkt++)
	if (clkt->mult < minmult)
	minmult = clkt->mult;
	return minmult;
	}

	static unsigned int _get_table_maxmult(const struct clk_mult_table *table)
	{
	unsigned int maxmult = 0;
	const struct clk_mult_table *clkt;

	for (clkt = table; clkt->mult; clkt++)
	if (clkt->mult > maxmult)
	maxmult = clkt->mult;
	return maxmult;
	}

	static unsigned int _get_minmult(const struct clk_mult_table *table)
	{
	if (table)
	return _get_table_minmult(table);
	return 1;
	}

	static unsigned int _get_maxmult(const struct clk_mult_table *table, u8 width,
	unsigned long flags)
	{
	if (flags & CLK_MULTIPLIER_ONE_BASED)
	return mult_mask(width);
	if (flags & CLK_MULTIPLIER_POWER_OF_TWO)
	return 1 << mult_mask(width);
	if (table)
	return _get_table_maxmult(table);
	return mult_mask(width) + 1;
	}

	static unsigned int _get_table_mult(const struct clk_mult_table *table,
	unsigned int val)
	{
	const struct clk_mult_table *clkt;

	for (clkt = table; clkt->mult; clkt++)
	if (clkt->val == val)
	return clkt->mult;
	return 0;
	}

	static unsigned int _get_mult(const struct clk_mult_table *table,
	u8 width, unsigned int val, unsigned long flags)
	{
	if (flags & CLK_MULTIPLIER_ONE_BASED)
	return val;
	if (flags & CLK_MULTIPLIER_POWER_OF_TWO)
	return 1 << val;
	if (flags & CLK_MULTIPLIER_MAX_MULT_AT_ZERO)
	return val ? val : mult_mask(width) + 1;
	if (table)
	return _get_table_mult(table, val);
	return val + 1;
	}

	static unsigned int _get_table_val(const struct clk_mult_table *table,
	unsigned int mult)
	{
	const struct clk_mult_table *clkt;

	for (clkt = table; clkt->mult; clkt++)
	if (clkt->mult == mult)
	return clkt->val;
	return 0;
	}

	static unsigned int _get_val(const struct clk_mult_table *table,
	u8 width, unsigned int mult, unsigned long flags)
	{
	if (flags & CLK_MULTIPLIER_ONE_BASED)
	return mult;
	if (flags & CLK_MULTIPLIER_POWER_OF_TWO)
	return __ffs(mult);
	if (flags & CLK_MULTIPLIER_MAX_MULT_AT_ZERO)
	return (mult == mult_mask(width) + 1)
	? 0 : mult;
	if (table)
	return _get_table_val(table, mult);
	return mult - 1;
	}

	unsigned long multiplier_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate,
	unsigned int val,
	const struct clk_mult_table *table,
	unsigned long flags)
	{
	struct clk_multiplier *multiplier = to_clk_multiplier(hw);
	unsigned int mult;

	mult = _get_mult(table, multiplier->width, val, flags);
	if (!mult) {
	WARN(!(flags & CLK_MULTIPLIER_ALLOW_ZERO),
	"%s: Zero multiplier and CLK_MULTIPLIER_ALLOW_ZERO not set\n",
	__clk_get_name(hw->clk));
	return parent_rate;
	}

	return parent_rate * mult;
	}
	EXPORT_SYMBOL_GPL(multiplier_recalc_rate);

	static unsigned long clk_multiplier_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate)
	{
	struct clk_multiplier *multiplier = to_clk_multiplier(hw);
	unsigned int val;

	val = clk_readl(multiplier->reg) >> multiplier->shift;
	val &= mult_mask(multiplier->width);

	return multiplier_recalc_rate(hw, parent_rate, val, multiplier->table,
	multiplier->flags);
	}

	static bool _is_valid_table_mult(const struct clk_mult_table *table,
	unsigned int mult)
	{
	const struct clk_mult_table *clkt;

	for (clkt = table; clkt->mult; clkt++)
	if (clkt->mult == mult)
	return true;
	return false;
	}

	static bool _is_valid_mult(const struct clk_mult_table *table,
	unsigned int mult, unsigned long flags)
	{
	if (flags & CLK_MULTIPLIER_POWER_OF_TWO)
	return is_power_of_2(mult);
	if (table)
	return _is_valid_table_mult(table, mult);
	return true;
	}

	static int clk_multiplier_bestmult(struct clk_hw *hw, unsigned long rate,
	unsigned long *best_parent_rate,
	const struct clk_mult_table *table, u8 width,
	unsigned long flags)
	{
	int i, bestmult = 0;
	unsigned long parent_rate, best = 0, now, maxmult, minmult;
	unsigned long parent_rate_saved = *best_parent_rate;

	if (!rate)
	rate = 1;

	minmult = _get_minmult(table);
	maxmult = _get_maxmult(table, width, flags);

	if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
	parent_rate = *best_parent_rate;
	bestmult = rate / parent_rate;
	bestmult = bestmult == 0 ? minmult : bestmult;
	bestmult = bestmult > maxmult ? maxmult : bestmult;
	return bestmult;
	}

	/*
	* The maximum multiplier we can use without overflowing
	* unsigned long in rate * i below
	*/
	maxmult = min(ULONG_MAX / parent_rate_saved, maxmult);

	for (i = 1; i <= maxmult; i++) {
	if (!_is_valid_mult(table, i, flags))
	continue;
	if (rate == parent_rate_saved * i) {
	/*
	* It's the most ideal case if the requested rate can be
	* multiplied from parent clock without needing to
	* change the parent rate, so return the multiplier
	* immediately.
	*/
	*best_parent_rate = parent_rate_saved;
	return i;
	}
	parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
	rate / i);
	now = parent_rate * i;
	if (now <= rate && now > best) {
	bestmult = i;
	best = now;
	*best_parent_rate = parent_rate;
	}
	}

	if (!bestmult) {
	bestmult = _get_minmult(table);
	*best_parent_rate
	= __clk_round_rate(__clk_get_parent(hw->clk), 1);
	}

	return bestmult;
	}

	long multiplier_round_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long *prate,
	const struct clk_mult_table *table,
	u8 width, unsigned long flags)
	{
	int mult;

	mult = clk_multiplier_bestmult(hw, rate, prate, table, width, flags);

	return prate mult;
	}
	EXPORT_SYMBOL_GPL(multiplier_round_rate);

	static long clk_multiplier_round_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long *prate)
	{
	struct clk_multiplier *multiplier = to_clk_multiplier(hw);
	int bestmult;

	/* if read only, just return current value */
	if (multiplier->flags & CLK_MULTIPLIER_READ_ONLY) {
	bestmult = readl(multiplier->reg) >> multiplier->shift;
	bestmult &= mult_mask(multiplier->width);
	bestmult = _get_mult(multiplier->table, multiplier->width,
	bestmult, multiplier->flags);
	if ((__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT))
	*prate = __clk_round_rate(__clk_get_parent(hw->clk),
	rate);
	return prate bestmult;
	}

	return multiplier_round_rate(hw, rate, prate, multiplier->table,
	multiplier->width, multiplier->flags);
	}

	int multiplier_get_val(unsigned long rate, unsigned long parent_rate,
	const struct clk_mult_table *table, u8 width,
	unsigned long flags)
	{
	unsigned int mult, value;

	mult = rate / parent_rate;
	value = _get_val(table, width, mult, flags);
	return min_t(unsigned int, value, mult_mask(width));
	}
	EXPORT_SYMBOL_GPL(multiplier_get_val);

	static int clk_multiplier_set_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long parent_rate)
	{
	struct clk_multiplier *multiplier = to_clk_multiplier(hw);
	unsigned int value;
	unsigned long flags = 0;
	u32 val;

	value = multiplier_get_val(rate, parent_rate, multiplier->table,
	multiplier->width, multiplier->flags);

	if (multiplier->lock)
	spin_lock_irqsave(multiplier->lock, flags);

	if (multiplier->flags & CLK_MULTIPLIER_HIWORD_MASK) {
	val = mult_mask(multiplier->width) << (multiplier->shift + 16);
	} else {
	val = clk_readl(multiplier->reg);
	val &= ~(mult_mask(multiplier->width) << multiplier->shift);
	}
	val \|= value << multiplier->shift;
	clk_writel(val, multiplier->reg);

	if (multiplier->lock)
	spin_unlock_irqrestore(multiplier->lock, flags);

	return 0;
	}

	const struct clk_ops clk_multiplier_ops = {
	.recalc_rate = clk_multiplier_recalc_rate,
	.round_rate = clk_multiplier_round_rate,
	.set_rate = clk_multiplier_set_rate,
	};
	EXPORT_SYMBOL_GPL(clk_multiplier_ops);

	const struct clk_ops clk_multiplier_ro_ops = {
	.recalc_rate = clk_multiplier_recalc_rate,
	};
	EXPORT_SYMBOL_GPL(clk_multiplier_ro_ops);

	static struct clk _register_multiplier(struct device dev, const char *name,
	const char *parent_name, unsigned long flags,
	void __iomem *reg, u8 shift, u8 width,
	u8 clk_multiplier_flags, const struct clk_mult_table *table,
	spinlock_t *lock)
	{
	struct clk_multiplier *mult;
	struct clk *clk;
	struct clk_init_data init;

	if (clk_multiplier_flags & CLK_MULTIPLIER_HIWORD_MASK) {
	if (width + shift > 16) {
	pr_warn("multiplier value exceeds LOWORD field\n");
	return ERR_PTR(-EINVAL);
	}
	}

	/* allocate the multiplier */
	mult = kzalloc(sizeof(struct clk_multiplier), GFP_KERNEL);
	if (!mult)
	return ERR_PTR(-ENOMEM);

	init.name = name;
	if (clk_multiplier_flags & CLK_MULTIPLIER_READ_ONLY)
	init.ops = &clk_multiplier_ro_ops;
	else
	init.ops = &clk_multiplier_ops;
	init.flags = flags \| CLK_IS_BASIC;
	init.parent_names = (parent_name ? &parent_name : NULL);
	init.num_parents = (parent_name ? 1 : 0);

	/* struct clk_multiplier assignments */
	mult->reg = reg;
	mult->shift = shift;
	mult->width = width;
	mult->flags = clk_multiplier_flags;
	mult->lock = lock;
	mult->hw.init = &init;
	mult->table = table;

	/* register the clock */
	clk = clk_register(dev, &mult->hw);

	if (IS_ERR(clk))
	kfree(mult);

	return clk;
	}

	/**
	* clk_register_multiplier - register a multiplier clock with the clock framework
	* @dev: device registering this clock
	* @name: name of this clock
	* @parent_name: name of clock's parent
	* @flags: framework-specific flags
	* @reg: register address to adjust multiplier
	* @shift: number of bits to shift the bitfield
	* @width: width of the bitfield
	* @clk_multiplier_flags: multiplier-specific flags for this clock
	* @lock: shared register lock for this clock
	*/
	struct clk clk_register_multiplier(struct device dev, const char *name,
	const char *parent_name, unsigned long flags,
	void __iomem *reg, u8 shift, u8 width,
	u8 clk_multiplier_flags, spinlock_t *lock)
	{
	return _register_multiplier(dev, name, parent_name, flags, reg, shift,
	width, clk_multiplier_flags, NULL, lock);
	}
	EXPORT_SYMBOL_GPL(clk_register_multiplier);

	/**
	* clk_register_multiplier_table - register a table based multiplier clock with
	* the clock framework
	* @dev: device registering this clock
	* @name: name of this clock
	* @parent_name: name of clock's parent
	* @flags: framework-specific flags
	* @reg: register address to adjust multiplier
	* @shift: number of bits to shift the bitfield
	* @width: width of the bitfield
	* @clk_multiplier_flags: multiplier-specific flags for this clock
	* @table: array of multiplier/value pairs ending with a mult set to 0
	* @lock: shared register lock for this clock
	*/
	struct clk clk_register_multiplier_table(struct device dev, const char *name,
	const char *parent_name, unsigned long flags,
	void __iomem *reg, u8 shift, u8 width,
	u8 clk_multiplier_flags, const struct clk_mult_table *table,
	spinlock_t *lock)
	{
	return _register_multiplier(dev, name, parent_name, flags, reg, shift,
	width, clk_multiplier_flags, table, lock);
	}
	EXPORT_SYMBOL_GPL(clk_register_multiplier_table);

	void clk_unregister_multiplier(struct clk *clk)
	{
	struct clk_multiplier *mult;
	struct clk_hw *hw;

	hw = __clk_get_hw(clk);
	if (!hw)
	return;

	mult = to_clk_multiplier(hw);

	clk_unregister(clk);
	kfree(mult);
	}
	EXPORT_SYMBOL_GPL(clk_unregister_multiplier);

	#ifdef CONFIG_OF
	static struct clk_mult_table of_clk_get_mult_table(struct device_node node)
	{
	int i;
	unsigned int table_size;
	struct clk_mult_table *table;
	const __be32 *tablespec;
	u32 val;

	tablespec = of_get_property(node, "table", (int *) &table_size);

	if (!tablespec)
	return NULL;

	table_size /= sizeof(struct clk_mult_table);

	if (!table_size) {
	pr_err("%s: %s table has zero length\n", __func__,
	node->name);
	return ERR_PTR(-EINVAL);
	}

	table = kzalloc(sizeof(struct clk_mult_table) * (table_size + 1),
	GFP_KERNEL);
	if (!table) {
	pr_err("%s: unable to allocate memory for %s table\n", __func__,
	node->name);
	return NULL;
	}

	for (i = 0; i < table_size; i++) {
	of_property_read_u32_index(node, "table", i * 2, &val);
	table[i].mult = val;
	of_property_read_u32_index(node, "table", i * 2 + 1, &val);
	table[i].val = val;
	}

	return table;
	}

	/**
	* of_multiplier_clk_setup() - Setup function for simple mult rate clock
	*/
	void of_multiplier_clk_setup(struct device_node *node)
	{
	struct clk *clk;
	const char *clk_name = node->name;
	void __iomem *reg;
	const char *parent_name;
	u8 clk_multiplier_flags = 0;
	u32 mask = 0;
	u32 shift = 0;
	u32 width;
	struct clk_mult_table *table;

	of_property_read_string(node, "clock-output-names", &clk_name);

	parent_name = of_clk_get_parent_name(node, 0);

	reg = of_iomap(node, 0);
	if (!reg) {
	pr_err("%s: no memory mapped for property reg\n", __func__);
	return;
	}

	if (of_property_read_u32(node, "bit-mask", &mask)) {
	pr_err("%s: missing bit-mask property for %s\n", __func__,
	node->name);
	return;
	}
	width = fls(mask);
	if ((1 << width) - 1 != mask) {
	pr_err("%s: bad bit-mask for %s\n", __func__, node->name);
	return;
	}

	if (of_property_read_u32(node, "bit-shift", &shift)) {
	shift = __ffs(mask);
	pr_debug("%s: bit-shift property defaults to 0x%x for %s\n",
	__func__, shift, node->name);
	}

	if (of_property_read_bool(node, "index-starts-at-one"))
	clk_multiplier_flags \|= CLK_MULTIPLIER_ONE_BASED;

	if (of_property_read_bool(node, "index-power-of-two"))
	clk_multiplier_flags \|= CLK_MULTIPLIER_POWER_OF_TWO;

	if (of_property_read_bool(node, "index-allow-zero"))
	clk_multiplier_flags \|= CLK_MULTIPLIER_ALLOW_ZERO;

	if (of_property_read_bool(node, "index-max-mult-at-zero"))
	clk_multiplier_flags \|= CLK_MULTIPLIER_MAX_MULT_AT_ZERO;

	table = of_clk_get_mult_table(node);
	if (IS_ERR(table))
	return;

	clk = _register_multiplier(NULL, clk_name, parent_name, 0, reg, shift,
	width, clk_multiplier_flags, table, NULL);

	if (!IS_ERR(clk))
	of_clk_add_provider(node, of_clk_src_simple_get, clk);
	}
	EXPORT_SYMBOL_GPL(of_multiplier_clk_setup);
	CLK_OF_DECLARE(multiplier_clk, "multiplier-clock", of_multiplier_clk_setup);
	#endif