arch/arm/mach-davinci/clock.c - third_party/linux - Git at Google

 /*
  * Clock and PLL control for DaVinci devices
  *
  * Copyright (C) 2006-2007 Texas Instruments.
  * Copyright (C) 2008-2009 Deep Root Systems, LLC
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
 #include <linux/io.h>
 #include <linux/delay.h>

 #include <mach/hardware.h>

 #include <mach/clock.h>
 #include <mach/psc.h>
 #include <mach/cputype.h>
 #include "clock.h"

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

 static unsigned psc_domain(struct clk *clk)
 {
 	return (clk->flags & PSC_DSP)
 		? DAVINCI_GPSC_DSPDOMAIN
 		: DAVINCI_GPSC_ARMDOMAIN;
 }

 static void __clk_enable(struct clk *clk)
 {
 	if (clk->parent)
 		__clk_enable(clk->parent);
 	if (clk->usecount++ == 0 && (clk->flags & CLK_PSC))
 		davinci_psc_config(psc_domain(clk), clk->gpsc, clk->lpsc,
 				true, clk->flags);
 }

 static void __clk_disable(struct clk *clk)
 {
 	if (WARN_ON(clk->usecount == 0))
 		return;
 	if (--clk->usecount == 0 && !(clk->flags & CLK_PLL) &&
 	    (clk->flags & CLK_PSC))
 		davinci_psc_config(psc_domain(clk), clk->gpsc, clk->lpsc,
 				false, clk->flags);
 	if (clk->parent)
 		__clk_disable(clk->parent);
 }

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

 	if (clk == NULL || IS_ERR(clk))
 		return -EINVAL;

 	spin_lock_irqsave(&clockfw_lock, flags);
 	__clk_enable(clk);
 	spin_unlock_irqrestore(&clockfw_lock, flags);

 	return 0;
 }
 EXPORT_SYMBOL(clk_enable);

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

 	if (clk == NULL || IS_ERR(clk))
 		return;

 	spin_lock_irqsave(&clockfw_lock, flags);
 	__clk_disable(clk);
 	spin_unlock_irqrestore(&clockfw_lock, flags);
 }
 EXPORT_SYMBOL(clk_disable);

 unsigned long clk_get_rate(struct clk *clk)
 {
 	if (clk == NULL || IS_ERR(clk))
 		return -EINVAL;

 	return clk->rate;
 }
 EXPORT_SYMBOL(clk_get_rate);

 long clk_round_rate(struct clk *clk, unsigned long rate)
 {
 	if (clk == NULL || IS_ERR(clk))
 		return -EINVAL;

 	if (clk->round_rate)
 		return clk->round_rate(clk, rate);

 	return clk->rate;
 }
 EXPORT_SYMBOL(clk_round_rate);

 /* Propagate rate to children */
 static void propagate_rate(struct clk *root)
 {
 	struct clk *clk;

 	list_for_each_entry(clk, &root->children, childnode) {
 		if (clk->recalc)
 			clk->rate = clk->recalc(clk);
 		propagate_rate(clk);
 	}
 }

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

 	if (clk == NULL || IS_ERR(clk))
 		return ret;

 	if (clk->set_rate)
 		ret = clk->set_rate(clk, rate);

 	spin_lock_irqsave(&clockfw_lock, flags);
 	if (ret == 0) {
 		if (clk->recalc)
 			clk->rate = clk->recalc(clk);
 		propagate_rate(clk);
 	}
 	spin_unlock_irqrestore(&clockfw_lock, flags);

 	return ret;
 }
 EXPORT_SYMBOL(clk_set_rate);

 int clk_set_parent(struct clk *clk, struct clk *parent)
 {
 	unsigned long flags;

 	if (clk == NULL || IS_ERR(clk))
 		return -EINVAL;

 	/* Cannot change parent on enabled clock */
 	if (WARN_ON(clk->usecount))
 		return -EINVAL;

 	mutex_lock(&clocks_mutex);
 	clk->parent = parent;
 	list_del_init(&clk->childnode);
 	list_add(&clk->childnode, &clk->parent->children);
 	mutex_unlock(&clocks_mutex);

 	spin_lock_irqsave(&clockfw_lock, flags);
 	if (clk->recalc)
 		clk->rate = clk->recalc(clk);
 	propagate_rate(clk);
 	spin_unlock_irqrestore(&clockfw_lock, flags);

 	return 0;
 }
 EXPORT_SYMBOL(clk_set_parent);

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

 	if (WARN(clk->parent && !clk->parent->rate,
 			"CLK: %s parent %s has no rate!\n",
 			clk->name, clk->parent->name))
 		return -EINVAL;

 	INIT_LIST_HEAD(&clk->children);

 	mutex_lock(&clocks_mutex);
 	list_add_tail(&clk->node, &clocks);
 	if (clk->parent)
 		list_add_tail(&clk->childnode, &clk->parent->children);
 	mutex_unlock(&clocks_mutex);

 	/* If rate is already set, use it */
 	if (clk->rate)
 		return 0;

 	/* Else, see if there is a way to calculate it */
 	if (clk->recalc)
 		clk->rate = clk->recalc(clk);

 	/* Otherwise, default to parent rate */
 	else if (clk->parent)
 		clk->rate = clk->parent->rate;

 	return 0;
 }
 EXPORT_SYMBOL(clk_register);

 void clk_unregister(struct clk *clk)
 {
 	if (clk == NULL || IS_ERR(clk))
 		return;

 	mutex_lock(&clocks_mutex);
 	list_del(&clk->node);
 	list_del(&clk->childnode);
 	mutex_unlock(&clocks_mutex);
 }
 EXPORT_SYMBOL(clk_unregister);

 #ifdef CONFIG_DAVINCI_RESET_CLOCKS
 /*
  * Disable any unused clocks left on by the bootloader
  */
 static int __init clk_disable_unused(void)
 {
 	struct clk *ck;

 	spin_lock_irq(&clockfw_lock);
 	list_for_each_entry(ck, &clocks, node) {
 		if (ck->usecount > 0)
 			continue;
 		if (!(ck->flags & CLK_PSC))
 			continue;

 		/* ignore if in Disabled or SwRstDisable states */
 		if (!davinci_psc_is_clk_active(ck->gpsc, ck->lpsc))
 			continue;

 		pr_debug("Clocks: disable unused %s\n", ck->name);

 		davinci_psc_config(psc_domain(ck), ck->gpsc, ck->lpsc,
 				false, ck->flags);
 	}
 	spin_unlock_irq(&clockfw_lock);

 	return 0;
 }
 late_initcall(clk_disable_unused);
 #endif

 static unsigned long clk_sysclk_recalc(struct clk *clk)
 {
 	u32 v, plldiv;
 	struct pll_data *pll;
 	unsigned long rate = clk->rate;

 	/* If this is the PLL base clock, no more calculations needed */
 	if (clk->pll_data)
 		return rate;

 	if (WARN_ON(!clk->parent))
 		return rate;

 	rate = clk->parent->rate;

 	/* Otherwise, the parent must be a PLL */
 	if (WARN_ON(!clk->parent->pll_data))
 		return rate;

 	pll = clk->parent->pll_data;

 	/* If pre-PLL, source clock is before the multiplier and divider(s) */
 	if (clk->flags & PRE_PLL)
 		rate = pll->input_rate;

 	if (!clk->div_reg)
 		return rate;

 	v = __raw_readl(pll->base + clk->div_reg);
 	if (v & PLLDIV_EN) {
 		plldiv = (v & pll->div_ratio_mask) + 1;
 		if (plldiv)
 			rate /= plldiv;
 	}

 	return rate;
 }

 int davinci_set_sysclk_rate(struct clk *clk, unsigned long rate)
 {
 	unsigned v;
 	struct pll_data *pll;
 	unsigned long input;
 	unsigned ratio = 0;

 	/* If this is the PLL base clock, wrong function to call */
 	if (clk->pll_data)
 		return -EINVAL;

 	/* There must be a parent... */
 	if (WARN_ON(!clk->parent))
 		return -EINVAL;

 	/* ... the parent must be a PLL... */
 	if (WARN_ON(!clk->parent->pll_data))
 		return -EINVAL;

 	/* ... and this clock must have a divider. */
 	if (WARN_ON(!clk->div_reg))
 		return -EINVAL;

 	pll = clk->parent->pll_data;

 	input = clk->parent->rate;

 	/* If pre-PLL, source clock is before the multiplier and divider(s) */
 	if (clk->flags & PRE_PLL)
 		input = pll->input_rate;

 	if (input > rate) {
 		/*
 		 * Can afford to provide an output little higher than requested
 		 * only if maximum rate supported by hardware on this sysclk
 		 * is known.
 		 */
 		if (clk->maxrate) {
 			ratio = DIV_ROUND_CLOSEST(input, rate);
 			if (input / ratio > clk->maxrate)
 				ratio = 0;
 		}

 		if (ratio == 0)
 			ratio = DIV_ROUND_UP(input, rate);

 		ratio--;
 	}

 	if (ratio > pll->div_ratio_mask)
 		return -EINVAL;

 	do {
 		v = __raw_readl(pll->base + PLLSTAT);
 	} while (v & PLLSTAT_GOSTAT);

 	v = __raw_readl(pll->base + clk->div_reg);
 	v &= ~pll->div_ratio_mask;
 	v |= ratio | PLLDIV_EN;
 	__raw_writel(v, pll->base + clk->div_reg);

 	v = __raw_readl(pll->base + PLLCMD);
 	v |= PLLCMD_GOSET;
 	__raw_writel(v, pll->base + PLLCMD);

 	do {
 		v = __raw_readl(pll->base + PLLSTAT);
 	} while (v & PLLSTAT_GOSTAT);

 	return 0;
 }
 EXPORT_SYMBOL(davinci_set_sysclk_rate);

 static unsigned long clk_leafclk_recalc(struct clk *clk)
 {
 	if (WARN_ON(!clk->parent))
 		return clk->rate;

 	return clk->parent->rate;
 }

 int davinci_simple_set_rate(struct clk *clk, unsigned long rate)
 {
 	clk->rate = rate;
 	return 0;
 }

 static unsigned long clk_pllclk_recalc(struct clk *clk)
 {
 	u32 ctrl, mult = 1, prediv = 1, postdiv = 1;
 	u8 bypass;
 	struct pll_data *pll = clk->pll_data;
 	unsigned long rate = clk->rate;

 	ctrl = __raw_readl(pll->base + PLLCTL);
 	rate = pll->input_rate = clk->parent->rate;

 	if (ctrl & PLLCTL_PLLEN) {
 		bypass = 0;
 		mult = __raw_readl(pll->base + PLLM);
 		if (cpu_is_davinci_dm365())
 			mult = 2 * (mult & PLLM_PLLM_MASK);
 		else
 			mult = (mult & PLLM_PLLM_MASK) + 1;
 	} else
 		bypass = 1;

 	if (pll->flags & PLL_HAS_PREDIV) {
 		prediv = __raw_readl(pll->base + PREDIV);
 		if (prediv & PLLDIV_EN)
 			prediv = (prediv & pll->div_ratio_mask) + 1;
 		else
 			prediv = 1;
 	}

 	/* pre-divider is fixed, but (some?) chips won't report that */
 	if (cpu_is_davinci_dm355() && pll->num == 1)
 		prediv = 8;

 	if (pll->flags & PLL_HAS_POSTDIV) {
 		postdiv = __raw_readl(pll->base + POSTDIV);
 		if (postdiv & PLLDIV_EN)
 			postdiv = (postdiv & pll->div_ratio_mask) + 1;
 		else
 			postdiv = 1;
 	}

 	if (!bypass) {
 		rate /= prediv;
 		rate *= mult;
 		rate /= postdiv;
 	}

 	pr_debug("PLL%d: input = %lu MHz [ ",
 		 pll->num, clk->parent->rate / 1000000);
 	if (bypass)
 		pr_debug("bypass ");
 	if (prediv > 1)
 		pr_debug("/ %d ", prediv);
 	if (mult > 1)
 		pr_debug("* %d ", mult);
 	if (postdiv > 1)
 		pr_debug("/ %d ", postdiv);
 	pr_debug("] --> %lu MHz output.\n", rate / 1000000);

 	return rate;
 }

 /**
  * davinci_set_pllrate - set the output rate of a given PLL.
  *
  * Note: Currently tested to work with OMAP-L138 only.
  *
  * @pll: pll whose rate needs to be changed.
  * @prediv: The pre divider value. Passing 0 disables the pre-divider.
  * @pllm: The multiplier value. Passing 0 leads to multiply-by-one.
  * @postdiv: The post divider value. Passing 0 disables the post-divider.
  */
 int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv,
 					unsigned int mult, unsigned int postdiv)
 {
 	u32 ctrl;
 	unsigned int locktime;
 	unsigned long flags;

 	if (pll->base == NULL)
 		return -EINVAL;

 	/*
 	 *  PLL lock time required per OMAP-L138 datasheet is
 	 * (2000 * prediv)/sqrt(pllm) OSCIN cycles. We approximate sqrt(pllm)
 	 * as 4 and OSCIN cycle as 25 MHz.
 	 */
 	if (prediv) {
 		locktime = ((2000 * prediv) / 100);
 		prediv = (prediv - 1) | PLLDIV_EN;
 	} else {
 		locktime = PLL_LOCK_TIME;
 	}
 	if (postdiv)
 		postdiv = (postdiv - 1) | PLLDIV_EN;
 	if (mult)
 		mult = mult - 1;

 	/* Protect against simultaneous calls to PLL setting seqeunce */
 	spin_lock_irqsave(&clockfw_lock, flags);

 	ctrl = __raw_readl(pll->base + PLLCTL);

 	/* Switch the PLL to bypass mode */
 	ctrl &= ~(PLLCTL_PLLENSRC | PLLCTL_PLLEN);
 	__raw_writel(ctrl, pll->base + PLLCTL);

 	udelay(PLL_BYPASS_TIME);

 	/* Reset and enable PLL */
 	ctrl &= ~(PLLCTL_PLLRST | PLLCTL_PLLDIS);
 	__raw_writel(ctrl, pll->base + PLLCTL);

 	if (pll->flags & PLL_HAS_PREDIV)
 		__raw_writel(prediv, pll->base + PREDIV);

 	__raw_writel(mult, pll->base + PLLM);

 	if (pll->flags & PLL_HAS_POSTDIV)
 		__raw_writel(postdiv, pll->base + POSTDIV);

 	udelay(PLL_RESET_TIME);

 	/* Bring PLL out of reset */
 	ctrl |= PLLCTL_PLLRST;
 	__raw_writel(ctrl, pll->base + PLLCTL);

 	udelay(locktime);

 	/* Remove PLL from bypass mode */
 	ctrl |= PLLCTL_PLLEN;
 	__raw_writel(ctrl, pll->base + PLLCTL);

 	spin_unlock_irqrestore(&clockfw_lock, flags);

 	return 0;
 }
 EXPORT_SYMBOL(davinci_set_pllrate);

 /**
  * davinci_set_refclk_rate() - Set the reference clock rate
  * @rate:	The new rate.
  *
  * Sets the reference clock rate to a given value. This will most likely
  * result in the entire clock tree getting updated.
  *
  * This is used to support boards which use a reference clock different
  * than that used by default in <soc>.c file. The reference clock rate
  * should be updated early in the boot process; ideally soon after the
  * clock tree has been initialized once with the default reference clock
  * rate (davinci_common_init()).
  *
  * Returns 0 on success, error otherwise.
  */
 int davinci_set_refclk_rate(unsigned long rate)
 {
 	struct clk *refclk;

 	refclk = clk_get(NULL, "ref");
 	if (IS_ERR(refclk)) {
 		pr_err("%s: failed to get reference clock.\n", __func__);
 		return PTR_ERR(refclk);
 	}

 	clk_set_rate(refclk, rate);

 	clk_put(refclk);

 	return 0;
 }

 int __init davinci_clk_init(struct clk_lookup *clocks)
   {
 	struct clk_lookup *c;
 	struct clk *clk;
 	size_t num_clocks = 0;

 	for (c = clocks; c->clk; c++) {
 		clk = c->clk;

 		if (!clk->recalc) {

 			/* Check if clock is a PLL */
 			if (clk->pll_data)
 				clk->recalc = clk_pllclk_recalc;

 			/* Else, if it is a PLL-derived clock */
 			else if (clk->flags & CLK_PLL)
 				clk->recalc = clk_sysclk_recalc;

 			/* Otherwise, it is a leaf clock (PSC clock) */
 			else if (clk->parent)
 				clk->recalc = clk_leafclk_recalc;
 		}

 		if (clk->pll_data) {
 			struct pll_data *pll = clk->pll_data;

 			if (!pll->div_ratio_mask)
 				pll->div_ratio_mask = PLLDIV_RATIO_MASK;

 			if (pll->phys_base && !pll->base) {
 				pll->base = ioremap(pll->phys_base, SZ_4K);
 				WARN_ON(!pll->base);
 			}
 		}

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

 		if (clk->lpsc)
 			clk->flags |= CLK_PSC;

 		clk_register(clk);
 		num_clocks++;

 		/* Turn on clocks that Linux doesn't otherwise manage */
 		if (clk->flags & ALWAYS_ENABLED)
 			clk_enable(clk);
 	}

 	clkdev_add_table(clocks, num_clocks);

 	return 0;
 }

 #ifdef CONFIG_DEBUG_FS

 #include <linux/debugfs.h>
 #include <linux/seq_file.h>

 #define CLKNAME_MAX	10		/* longest clock name */
 #define NEST_DELTA	2
 #define NEST_MAX	4

 static void
 dump_clock(struct seq_file *s, unsigned nest, struct clk *parent)
 {
 	char		*state;
 	char		buf[CLKNAME_MAX + NEST_DELTA * NEST_MAX];
 	struct clk	*clk;
 	unsigned	i;

 	if (parent->flags & CLK_PLL)
 		state = "pll";
 	else if (parent->flags & CLK_PSC)
 		state = "psc";
 	else
 		state = "";

 	/* <nest spaces> name <pad to end> */
 	memset(buf, ' ', sizeof(buf) - 1);
 	buf[sizeof(buf) - 1] = 0;
 	i = strlen(parent->name);
 	memcpy(buf + nest, parent->name,
 			min(i, (unsigned)(sizeof(buf) - 1 - nest)));

 	seq_printf(s, "%s users=%2d %-3s %9ld Hz\n",
 		   buf, parent->usecount, state, clk_get_rate(parent));
 	/* REVISIT show device associations too */

 	/* cost is now small, but not linear... */
 	list_for_each_entry(clk, &parent->children, childnode) {
 		dump_clock(s, nest + NEST_DELTA, clk);
 	}
 }

 static int davinci_ck_show(struct seq_file *m, void *v)
 {
 	struct clk *clk;

 	/*
 	 * Show clock tree; We trust nonzero usecounts equate to PSC enables...
 	 */
 	mutex_lock(&clocks_mutex);
 	list_for_each_entry(clk, &clocks, node)
 		if (!clk->parent)
 			dump_clock(m, 0, clk);
 	mutex_unlock(&clocks_mutex);

 	return 0;
 }

 static int davinci_ck_open(struct inode *inode, struct file *file)
 {
 	return single_open(file, davinci_ck_show, NULL);
 }

 static const struct file_operations davinci_ck_operations = {
 	.open		= davinci_ck_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 	.release	= single_release,
 };

 static int __init davinci_clk_debugfs_init(void)
 {
 	debugfs_create_file("davinci_clocks", S_IFREG | S_IRUGO, NULL, NULL,
 						&davinci_ck_operations);
 	return 0;

 }
 device_initcall(davinci_clk_debugfs_init);
 #endif /* CONFIG_DEBUG_FS */
	/*
	* Clock and PLL control for DaVinci devices
	*
	* Copyright (C) 2006-2007 Texas Instruments.
	* Copyright (C) 2008-2009 Deep Root Systems, LLC
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/errno.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/mutex.h>
	#include <linux/io.h>
	#include <linux/delay.h>

	#include <mach/hardware.h>

	#include <mach/clock.h>
	#include <mach/psc.h>
	#include <mach/cputype.h>
	#include "clock.h"

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

	static unsigned psc_domain(struct clk *clk)
	{
	return (clk->flags & PSC_DSP)
	? DAVINCI_GPSC_DSPDOMAIN
	: DAVINCI_GPSC_ARMDOMAIN;
	}

	static void __clk_enable(struct clk *clk)
	{
	if (clk->parent)
	__clk_enable(clk->parent);
	if (clk->usecount++ == 0 && (clk->flags & CLK_PSC))
	davinci_psc_config(psc_domain(clk), clk->gpsc, clk->lpsc,
	true, clk->flags);
	}

	static void __clk_disable(struct clk *clk)
	{
	if (WARN_ON(clk->usecount == 0))
	return;
	if (--clk->usecount == 0 && !(clk->flags & CLK_PLL) &&
	(clk->flags & CLK_PSC))
	davinci_psc_config(psc_domain(clk), clk->gpsc, clk->lpsc,
	false, clk->flags);
	if (clk->parent)
	__clk_disable(clk->parent);
	}

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

	if (clk == NULL \|\| IS_ERR(clk))
	return -EINVAL;

	spin_lock_irqsave(&clockfw_lock, flags);
	__clk_enable(clk);
	spin_unlock_irqrestore(&clockfw_lock, flags);

	return 0;
	}
	EXPORT_SYMBOL(clk_enable);

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

	if (clk == NULL \|\| IS_ERR(clk))
	return;

	spin_lock_irqsave(&clockfw_lock, flags);
	__clk_disable(clk);
	spin_unlock_irqrestore(&clockfw_lock, flags);
	}
	EXPORT_SYMBOL(clk_disable);

	unsigned long clk_get_rate(struct clk *clk)
	{
	if (clk == NULL \|\| IS_ERR(clk))
	return -EINVAL;

	return clk->rate;
	}
	EXPORT_SYMBOL(clk_get_rate);

	long clk_round_rate(struct clk *clk, unsigned long rate)
	{
	if (clk == NULL \|\| IS_ERR(clk))
	return -EINVAL;

	if (clk->round_rate)
	return clk->round_rate(clk, rate);

	return clk->rate;
	}
	EXPORT_SYMBOL(clk_round_rate);

	/* Propagate rate to children */
	static void propagate_rate(struct clk *root)
	{
	struct clk *clk;

	list_for_each_entry(clk, &root->children, childnode) {
	if (clk->recalc)
	clk->rate = clk->recalc(clk);
	propagate_rate(clk);
	}
	}

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

	if (clk == NULL \|\| IS_ERR(clk))
	return ret;

	if (clk->set_rate)
	ret = clk->set_rate(clk, rate);

	spin_lock_irqsave(&clockfw_lock, flags);
	if (ret == 0) {
	if (clk->recalc)
	clk->rate = clk->recalc(clk);
	propagate_rate(clk);
	}
	spin_unlock_irqrestore(&clockfw_lock, flags);

	return ret;
	}
	EXPORT_SYMBOL(clk_set_rate);

	int clk_set_parent(struct clk clk, struct clk parent)
	{
	unsigned long flags;

	if (clk == NULL \|\| IS_ERR(clk))
	return -EINVAL;

	/* Cannot change parent on enabled clock */
	if (WARN_ON(clk->usecount))
	return -EINVAL;

	mutex_lock(&clocks_mutex);
	clk->parent = parent;
	list_del_init(&clk->childnode);
	list_add(&clk->childnode, &clk->parent->children);
	mutex_unlock(&clocks_mutex);

	spin_lock_irqsave(&clockfw_lock, flags);
	if (clk->recalc)
	clk->rate = clk->recalc(clk);
	propagate_rate(clk);
	spin_unlock_irqrestore(&clockfw_lock, flags);

	return 0;
	}
	EXPORT_SYMBOL(clk_set_parent);

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

	if (WARN(clk->parent && !clk->parent->rate,
	"CLK: %s parent %s has no rate!\n",
	clk->name, clk->parent->name))
	return -EINVAL;

	INIT_LIST_HEAD(&clk->children);

	mutex_lock(&clocks_mutex);
	list_add_tail(&clk->node, &clocks);
	if (clk->parent)
	list_add_tail(&clk->childnode, &clk->parent->children);
	mutex_unlock(&clocks_mutex);

	/* If rate is already set, use it */
	if (clk->rate)
	return 0;

	/* Else, see if there is a way to calculate it */
	if (clk->recalc)
	clk->rate = clk->recalc(clk);

	/* Otherwise, default to parent rate */
	else if (clk->parent)
	clk->rate = clk->parent->rate;

	return 0;
	}
	EXPORT_SYMBOL(clk_register);

	void clk_unregister(struct clk *clk)
	{
	if (clk == NULL \|\| IS_ERR(clk))
	return;

	mutex_lock(&clocks_mutex);
	list_del(&clk->node);
	list_del(&clk->childnode);
	mutex_unlock(&clocks_mutex);
	}
	EXPORT_SYMBOL(clk_unregister);

	#ifdef CONFIG_DAVINCI_RESET_CLOCKS
	/*
	* Disable any unused clocks left on by the bootloader
	*/
	static int __init clk_disable_unused(void)
	{
	struct clk *ck;

	spin_lock_irq(&clockfw_lock);
	list_for_each_entry(ck, &clocks, node) {
	if (ck->usecount > 0)
	continue;
	if (!(ck->flags & CLK_PSC))
	continue;

	/* ignore if in Disabled or SwRstDisable states */
	if (!davinci_psc_is_clk_active(ck->gpsc, ck->lpsc))
	continue;

	pr_debug("Clocks: disable unused %s\n", ck->name);

	davinci_psc_config(psc_domain(ck), ck->gpsc, ck->lpsc,
	false, ck->flags);
	}
	spin_unlock_irq(&clockfw_lock);

	return 0;
	}
	late_initcall(clk_disable_unused);
	#endif

	static unsigned long clk_sysclk_recalc(struct clk *clk)
	{
	u32 v, plldiv;
	struct pll_data *pll;
	unsigned long rate = clk->rate;

	/* If this is the PLL base clock, no more calculations needed */
	if (clk->pll_data)
	return rate;

	if (WARN_ON(!clk->parent))
	return rate;

	rate = clk->parent->rate;

	/* Otherwise, the parent must be a PLL */
	if (WARN_ON(!clk->parent->pll_data))
	return rate;

	pll = clk->parent->pll_data;

	/* If pre-PLL, source clock is before the multiplier and divider(s) */
	if (clk->flags & PRE_PLL)
	rate = pll->input_rate;

	if (!clk->div_reg)
	return rate;

	v = __raw_readl(pll->base + clk->div_reg);
	if (v & PLLDIV_EN) {
	plldiv = (v & pll->div_ratio_mask) + 1;
	if (plldiv)
	rate /= plldiv;
	}

	return rate;
	}

	int davinci_set_sysclk_rate(struct clk *clk, unsigned long rate)
	{
	unsigned v;
	struct pll_data *pll;
	unsigned long input;
	unsigned ratio = 0;

	/* If this is the PLL base clock, wrong function to call */
	if (clk->pll_data)
	return -EINVAL;

	/* There must be a parent... */
	if (WARN_ON(!clk->parent))
	return -EINVAL;

	/* ... the parent must be a PLL... */
	if (WARN_ON(!clk->parent->pll_data))
	return -EINVAL;

	/* ... and this clock must have a divider. */
	if (WARN_ON(!clk->div_reg))
	return -EINVAL;

	pll = clk->parent->pll_data;

	input = clk->parent->rate;

	/* If pre-PLL, source clock is before the multiplier and divider(s) */
	if (clk->flags & PRE_PLL)
	input = pll->input_rate;

	if (input > rate) {
	/*
	* Can afford to provide an output little higher than requested
	* only if maximum rate supported by hardware on this sysclk
	* is known.
	*/
	if (clk->maxrate) {
	ratio = DIV_ROUND_CLOSEST(input, rate);
	if (input / ratio > clk->maxrate)
	ratio = 0;
	}

	if (ratio == 0)
	ratio = DIV_ROUND_UP(input, rate);

	ratio--;
	}

	if (ratio > pll->div_ratio_mask)
	return -EINVAL;

	do {
	v = __raw_readl(pll->base + PLLSTAT);
	} while (v & PLLSTAT_GOSTAT);

	v = __raw_readl(pll->base + clk->div_reg);
	v &= ~pll->div_ratio_mask;
	v \|= ratio \| PLLDIV_EN;
	__raw_writel(v, pll->base + clk->div_reg);

	v = __raw_readl(pll->base + PLLCMD);
	v \|= PLLCMD_GOSET;
	__raw_writel(v, pll->base + PLLCMD);

	do {
	v = __raw_readl(pll->base + PLLSTAT);
	} while (v & PLLSTAT_GOSTAT);

	return 0;
	}
	EXPORT_SYMBOL(davinci_set_sysclk_rate);

	static unsigned long clk_leafclk_recalc(struct clk *clk)
	{
	if (WARN_ON(!clk->parent))
	return clk->rate;

	return clk->parent->rate;
	}

	int davinci_simple_set_rate(struct clk *clk, unsigned long rate)
	{
	clk->rate = rate;
	return 0;
	}

	static unsigned long clk_pllclk_recalc(struct clk *clk)
	{
	u32 ctrl, mult = 1, prediv = 1, postdiv = 1;
	u8 bypass;
	struct pll_data *pll = clk->pll_data;
	unsigned long rate = clk->rate;

	ctrl = __raw_readl(pll->base + PLLCTL);
	rate = pll->input_rate = clk->parent->rate;

	if (ctrl & PLLCTL_PLLEN) {
	bypass = 0;
	mult = __raw_readl(pll->base + PLLM);
	if (cpu_is_davinci_dm365())
	mult = 2 * (mult & PLLM_PLLM_MASK);
	else
	mult = (mult & PLLM_PLLM_MASK) + 1;
	} else
	bypass = 1;

	if (pll->flags & PLL_HAS_PREDIV) {
	prediv = __raw_readl(pll->base + PREDIV);
	if (prediv & PLLDIV_EN)
	prediv = (prediv & pll->div_ratio_mask) + 1;
	else
	prediv = 1;
	}

	/* pre-divider is fixed, but (some?) chips won't report that */
	if (cpu_is_davinci_dm355() && pll->num == 1)
	prediv = 8;

	if (pll->flags & PLL_HAS_POSTDIV) {
	postdiv = __raw_readl(pll->base + POSTDIV);
	if (postdiv & PLLDIV_EN)
	postdiv = (postdiv & pll->div_ratio_mask) + 1;
	else
	postdiv = 1;
	}

	if (!bypass) {
	rate /= prediv;
	rate *= mult;
	rate /= postdiv;
	}

	pr_debug("PLL%d: input = %lu MHz [ ",
	pll->num, clk->parent->rate / 1000000);
	if (bypass)
	pr_debug("bypass ");
	if (prediv > 1)
	pr_debug("/ %d ", prediv);
	if (mult > 1)
	pr_debug("* %d ", mult);
	if (postdiv > 1)
	pr_debug("/ %d ", postdiv);
	pr_debug("] --> %lu MHz output.\n", rate / 1000000);

	return rate;
	}

	/**
	* davinci_set_pllrate - set the output rate of a given PLL.
	*
	* Note: Currently tested to work with OMAP-L138 only.
	*
	* @pll: pll whose rate needs to be changed.
	* @prediv: The pre divider value. Passing 0 disables the pre-divider.
	* @pllm: The multiplier value. Passing 0 leads to multiply-by-one.
	* @postdiv: The post divider value. Passing 0 disables the post-divider.
	*/
	int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv,
	unsigned int mult, unsigned int postdiv)
	{
	u32 ctrl;
	unsigned int locktime;
	unsigned long flags;

	if (pll->base == NULL)
	return -EINVAL;

	/*
	* PLL lock time required per OMAP-L138 datasheet is
	* (2000 * prediv)/sqrt(pllm) OSCIN cycles. We approximate sqrt(pllm)
	* as 4 and OSCIN cycle as 25 MHz.
	*/
	if (prediv) {
	locktime = ((2000 * prediv) / 100);
	prediv = (prediv - 1) \| PLLDIV_EN;
	} else {
	locktime = PLL_LOCK_TIME;
	}
	if (postdiv)
	postdiv = (postdiv - 1) \| PLLDIV_EN;
	if (mult)
	mult = mult - 1;

	/* Protect against simultaneous calls to PLL setting seqeunce */
	spin_lock_irqsave(&clockfw_lock, flags);

	ctrl = __raw_readl(pll->base + PLLCTL);

	/* Switch the PLL to bypass mode */
	ctrl &= ~(PLLCTL_PLLENSRC \| PLLCTL_PLLEN);
	__raw_writel(ctrl, pll->base + PLLCTL);

	udelay(PLL_BYPASS_TIME);

	/* Reset and enable PLL */
	ctrl &= ~(PLLCTL_PLLRST \| PLLCTL_PLLDIS);
	__raw_writel(ctrl, pll->base + PLLCTL);

	if (pll->flags & PLL_HAS_PREDIV)
	__raw_writel(prediv, pll->base + PREDIV);

	__raw_writel(mult, pll->base + PLLM);

	if (pll->flags & PLL_HAS_POSTDIV)
	__raw_writel(postdiv, pll->base + POSTDIV);

	udelay(PLL_RESET_TIME);

	/* Bring PLL out of reset */
	ctrl \|= PLLCTL_PLLRST;
	__raw_writel(ctrl, pll->base + PLLCTL);

	udelay(locktime);

	/* Remove PLL from bypass mode */
	ctrl \|= PLLCTL_PLLEN;
	__raw_writel(ctrl, pll->base + PLLCTL);

	spin_unlock_irqrestore(&clockfw_lock, flags);

	return 0;
	}
	EXPORT_SYMBOL(davinci_set_pllrate);

	/**
	* davinci_set_refclk_rate() - Set the reference clock rate
	* @rate: The new rate.
	*
	* Sets the reference clock rate to a given value. This will most likely
	* result in the entire clock tree getting updated.
	*
	* This is used to support boards which use a reference clock different
	* than that used by default in <soc>.c file. The reference clock rate
	* should be updated early in the boot process; ideally soon after the
	* clock tree has been initialized once with the default reference clock
	* rate (davinci_common_init()).
	*
	* Returns 0 on success, error otherwise.
	*/
	int davinci_set_refclk_rate(unsigned long rate)
	{
	struct clk *refclk;

	refclk = clk_get(NULL, "ref");
	if (IS_ERR(refclk)) {
	pr_err("%s: failed to get reference clock.\n", __func__);
	return PTR_ERR(refclk);
	}

	clk_set_rate(refclk, rate);

	clk_put(refclk);

	return 0;
	}

	int __init davinci_clk_init(struct clk_lookup *clocks)
	{
	struct clk_lookup *c;
	struct clk *clk;
	size_t num_clocks = 0;

	for (c = clocks; c->clk; c++) {
	clk = c->clk;

	if (!clk->recalc) {

	/* Check if clock is a PLL */
	if (clk->pll_data)
	clk->recalc = clk_pllclk_recalc;

	/* Else, if it is a PLL-derived clock */
	else if (clk->flags & CLK_PLL)
	clk->recalc = clk_sysclk_recalc;

	/* Otherwise, it is a leaf clock (PSC clock) */
	else if (clk->parent)
	clk->recalc = clk_leafclk_recalc;
	}

	if (clk->pll_data) {
	struct pll_data *pll = clk->pll_data;

	if (!pll->div_ratio_mask)
	pll->div_ratio_mask = PLLDIV_RATIO_MASK;

	if (pll->phys_base && !pll->base) {
	pll->base = ioremap(pll->phys_base, SZ_4K);
	WARN_ON(!pll->base);
	}
	}

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

	if (clk->lpsc)
	clk->flags \|= CLK_PSC;

	clk_register(clk);
	num_clocks++;

	/* Turn on clocks that Linux doesn't otherwise manage */
	if (clk->flags & ALWAYS_ENABLED)
	clk_enable(clk);
	}

	clkdev_add_table(clocks, num_clocks);

	return 0;
	}

	#ifdef CONFIG_DEBUG_FS

	#include <linux/debugfs.h>
	#include <linux/seq_file.h>

	#define CLKNAME_MAX 10 /* longest clock name */
	#define NEST_DELTA 2
	#define NEST_MAX 4

	static void
	dump_clock(struct seq_file s, unsigned nest, struct clk parent)
	{
	char *state;
	char buf[CLKNAME_MAX + NEST_DELTA * NEST_MAX];
	struct clk *clk;
	unsigned i;

	if (parent->flags & CLK_PLL)
	state = "pll";
	else if (parent->flags & CLK_PSC)
	state = "psc";
	else
	state = "";

	/* <nest spaces> name <pad to end> */
	memset(buf, ' ', sizeof(buf) - 1);
	buf[sizeof(buf) - 1] = 0;
	i = strlen(parent->name);
	memcpy(buf + nest, parent->name,
	min(i, (unsigned)(sizeof(buf) - 1 - nest)));

	seq_printf(s, "%s users=%2d %-3s %9ld Hz\n",
	buf, parent->usecount, state, clk_get_rate(parent));
	/* REVISIT show device associations too */

	/* cost is now small, but not linear... */
	list_for_each_entry(clk, &parent->children, childnode) {
	dump_clock(s, nest + NEST_DELTA, clk);
	}
	}

	static int davinci_ck_show(struct seq_file m, void v)
	{
	struct clk *clk;

	/*
	* Show clock tree; We trust nonzero usecounts equate to PSC enables...
	*/
	mutex_lock(&clocks_mutex);
	list_for_each_entry(clk, &clocks, node)
	if (!clk->parent)
	dump_clock(m, 0, clk);
	mutex_unlock(&clocks_mutex);

	return 0;
	}

	static int davinci_ck_open(struct inode inode, struct file file)
	{
	return single_open(file, davinci_ck_show, NULL);
	}

	static const struct file_operations davinci_ck_operations = {
	.open = davinci_ck_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
	};

	static int __init davinci_clk_debugfs_init(void)
	{
	debugfs_create_file("davinci_clocks", S_IFREG \| S_IRUGO, NULL, NULL,
	&davinci_ck_operations);
	return 0;

	}
	device_initcall(davinci_clk_debugfs_init);
	#endif /* CONFIG_DEBUG_FS */