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clock.c

/*
 *  linux/arch/arm/plat-omap/clock.c
 *
 *  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>
 *
 * 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.
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/clk.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/cpufreq.h>
#include <linux/debugfs.h>
#include <linux/io.h>

#include <mach/clock.h>

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

static struct clk_functions *arch_clock;

/*-------------------------------------------------------------------------
 * Standard clock functions defined in include/linux/clk.h
 *-------------------------------------------------------------------------*/

/* This functions is moved to arch/arm/common/clkdev.c. For OMAP4 since
 * clock framework is not up , it is defined here to avoid rework in
 * every driver. Also dummy prcm reset function is added */

/* Dummy hooks only for OMAP4.For rest OMAPs, common clkdev is used */
#if defined(CONFIG_ARCH_OMAP4)
struct clk *clk_get(struct device *dev, const char *id)
{
      return NULL;
}
EXPORT_SYMBOL(clk_get);

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

void omap2_clk_prepare_for_reboot(void)
{
}
EXPORT_SYMBOL(omap2_clk_prepare_for_reboot);

void omap_prcm_arch_reset(char mode)
{
}
EXPORT_SYMBOL(omap_prcm_arch_reset);
#endif
int clk_enable(struct clk *clk)
{
      unsigned long flags;
      int ret = 0;
      if (cpu_is_omap44xx())
            /* OMAP4 clk framework not supported yet */
            return 0;

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

      spin_lock_irqsave(&clockfw_lock, flags);
      if (arch_clock->clk_enable)
            ret = arch_clock->clk_enable(clk);
      spin_unlock_irqrestore(&clockfw_lock, flags);

      return ret;
}
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);
      if (clk->usecount == 0) {
            printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
                   clk->name);
            WARN_ON(1);
            goto out;
      }

      if (arch_clock->clk_disable)
            arch_clock->clk_disable(clk);

out:
      spin_unlock_irqrestore(&clockfw_lock, flags);
}
EXPORT_SYMBOL(clk_disable);

unsigned long clk_get_rate(struct clk *clk)
{
      unsigned long flags;
      unsigned long ret = 0;

      if (clk == NULL || IS_ERR(clk))
            return 0;

      spin_lock_irqsave(&clockfw_lock, flags);
      ret = clk->rate;
      spin_unlock_irqrestore(&clockfw_lock, flags);

      return ret;
}
EXPORT_SYMBOL(clk_get_rate);

/*-------------------------------------------------------------------------
 * Optional clock functions defined in include/linux/clk.h
 *-------------------------------------------------------------------------*/

long clk_round_rate(struct clk *clk, unsigned long rate)
{
      unsigned long flags;
      long ret = 0;

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

      spin_lock_irqsave(&clockfw_lock, flags);
      if (arch_clock->clk_round_rate)
            ret = arch_clock->clk_round_rate(clk, rate);
      spin_unlock_irqrestore(&clockfw_lock, flags);

      return ret;
}
EXPORT_SYMBOL(clk_round_rate);

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

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

      spin_lock_irqsave(&clockfw_lock, flags);
      if (arch_clock->clk_set_rate)
            ret = arch_clock->clk_set_rate(clk, rate);
      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;
      int ret = -EINVAL;

      if (cpu_is_omap44xx())
      /* OMAP4 clk framework not supported yet */
            return 0;
      if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
            return ret;

      spin_lock_irqsave(&clockfw_lock, flags);
      if (clk->usecount == 0) {
            if (arch_clock->clk_set_parent)
                  ret = arch_clock->clk_set_parent(clk, parent);
            if (ret == 0) {
                  if (clk->recalc)
                        clk->rate = clk->recalc(clk);
                  propagate_rate(clk);
            }
      } else
            ret = -EBUSY;
      spin_unlock_irqrestore(&clockfw_lock, flags);

      return ret;
}
EXPORT_SYMBOL(clk_set_parent);

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

/*-------------------------------------------------------------------------
 * OMAP specific clock functions shared between omap1 and omap2
 *-------------------------------------------------------------------------*/

unsigned int __initdata mpurate;

/*
 * By default we use the rate set by the bootloader.
 * You can override this with mpurate= cmdline option.
 */
static int __init omap_clk_setup(char *str)
{
      get_option(&str, &mpurate);

      if (!mpurate)
            return 1;

      if (mpurate < 1000)
            mpurate *= 1000000;

      return 1;
}
__setup("mpurate=", omap_clk_setup);

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

void 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 */
}

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

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

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->recalc)
                  clkp->rate = clkp->recalc(clkp);
            propagate_rate(clkp);
      }
}

/**
 * clk_preinit - initialize any fields in the struct clk before clk init
 * @clk: struct clk * to initialize
 *
 * Initialize any struct clk fields needed before normal clk initialization
 * can run.  No return value.
 */
void clk_preinit(struct clk *clk)
{
      INIT_LIST_HEAD(&clk->children);
}

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

      list_add(&clk->node, &clocks);
      if (clk->init)
            clk->init(clk);
      mutex_unlock(&clocks_mutex);

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

void clk_enable_init_clocks(void)
{
      struct clk *clkp;

      list_for_each_entry(clkp, &clocks, node) {
            if (clkp->flags & ENABLE_ON_INIT)
                  clk_enable(clkp);
      }
}
EXPORT_SYMBOL(clk_enable_init_clocks);

/*
 * Low level helpers
 */
static int clkll_enable_null(struct clk *clk)
{
      return 0;
}

static void clkll_disable_null(struct clk *clk)
{
}

const struct clkops clkops_null = {
      .enable           = clkll_enable_null,
      .disable    = clkll_disable_null,
};

#ifdef CONFIG_CPU_FREQ
void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
{
      unsigned long flags;

      spin_lock_irqsave(&clockfw_lock, flags);
      if (arch_clock->clk_init_cpufreq_table)
            arch_clock->clk_init_cpufreq_table(table);
      spin_unlock_irqrestore(&clockfw_lock, flags);
}
EXPORT_SYMBOL(clk_init_cpufreq_table);
#endif

/*-------------------------------------------------------------------------*/

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

      list_for_each_entry(ck, &clocks, node) {
            if (ck->ops == &clkops_null)
                  continue;

            if (ck->usecount > 0 || ck->enable_reg == 0)
                  continue;

            spin_lock_irqsave(&clockfw_lock, flags);
            if (arch_clock->clk_disable_unused)
                  arch_clock->clk_disable_unused(ck);
            spin_unlock_irqrestore(&clockfw_lock, flags);
      }

      return 0;
}
late_initcall(clk_disable_unused);
#endif

int __init clk_init(struct clk_functions * custom_clocks)
{
      if (!custom_clocks) {
            printk(KERN_ERR "No custom clock functions registered\n");
            BUG();
      }

      arch_clock = custom_clocks;

      return 0;
}

#if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
/*
 *    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;
      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->dent : clk_debugfs_root);
      if (!d)
            return -ENOMEM;
      c->dent = d;

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

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

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

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

      if (!c->dent) {
            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, &clocks, node) {
            err = clk_debugfs_register(c);
            if (err)
                  goto err_out;
      }
      return 0;
err_out:
      debugfs_remove_recursive(clk_debugfs_root);
      return err;
}
late_initcall(clk_debugfs_init);

#endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */

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