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clock.c

/* linux/arch/arm/plat-s3c24xx/clock.c
 *
 * Copyright (c) 2004-2005 Simtec Electronics
 *    Ben Dooks <ben@simtec.co.uk>
 *
 * S3C24XX Core clock control support
 *
 * Based on, and code from linux/arch/arm/mach-versatile/clock.c
 **
 **  Copyright (C) 2004 ARM Limited.
 **  Written by Deep Blue Solutions Limited.
 *
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/sysdev.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/clk.h>
#include <linux/spinlock.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <asm/irq.h>

#include <plat/cpu-freq.h>

#include <plat/clock.h>
#include <plat/cpu.h>

/* clock information */

static LIST_HEAD(clocks);

/* We originally used an mutex here, but some contexts (see resume)
 * are calling functions such as clk_set_parent() with IRQs disabled
 * causing an BUG to be triggered.
 */
DEFINE_SPINLOCK(clocks_lock);

/* enable and disable calls for use with the clk struct */

static int clk_null_enable(struct clk *clk, int enable)
{
      return 0;
}

/* Clock API calls */

struct clk *clk_get(struct device *dev, const char *id)
{
      struct clk *p;
      struct clk *clk = ERR_PTR(-ENOENT);
      int idno;

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

      spin_lock(&clocks_lock);

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

      /* check for the case where a device was supplied, but the
       * clock that was being searched for is not device specific */

      if (IS_ERR(clk)) {
            list_for_each_entry(p, &clocks, list) {
                  if (p->id == -1 && strcmp(id, p->name) == 0 &&
                      try_module_get(p->owner)) {
                        clk = p;
                        break;
                  }
            }
      }

      spin_unlock(&clocks_lock);
      return clk;
}

void clk_put(struct clk *clk)
{
      module_put(clk->owner);
}

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

      clk_enable(clk->parent);

      spin_lock(&clocks_lock);

      if ((clk->usage++) == 0)
            (clk->enable)(clk, 1);

      spin_unlock(&clocks_lock);
      return 0;
}

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

      spin_lock(&clocks_lock);

      if ((--clk->usage) == 0)
            (clk->enable)(clk, 0);

      spin_unlock(&clocks_lock);
      clk_disable(clk->parent);
}


unsigned long clk_get_rate(struct clk *clk)
{
      if (IS_ERR(clk))
            return 0;

      if (clk->rate != 0)
            return clk->rate;

      if (clk->get_rate != NULL)
            return (clk->get_rate)(clk);

      if (clk->parent != NULL)
            return clk_get_rate(clk->parent);

      return clk->rate;
}

long clk_round_rate(struct clk *clk, unsigned long rate)
{
      if (!IS_ERR(clk) && clk->round_rate)
            return (clk->round_rate)(clk, rate);

      return rate;
}

int clk_set_rate(struct clk *clk, unsigned long rate)
{
      int ret;

      if (IS_ERR(clk))
            return -EINVAL;

      /* We do not default just do a clk->rate = rate as
       * the clock may have been made this way by choice.
       */

      WARN_ON(clk->set_rate == NULL);

      if (clk->set_rate == NULL)
            return -EINVAL;

      spin_lock(&clocks_lock);
      ret = (clk->set_rate)(clk, rate);
      spin_unlock(&clocks_lock);

      return ret;
}

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

int clk_set_parent(struct clk *clk, struct clk *parent)
{
      int ret = 0;

      if (IS_ERR(clk))
            return -EINVAL;

      spin_lock(&clocks_lock);

      if (clk->set_parent)
            ret = (clk->set_parent)(clk, parent);

      spin_unlock(&clocks_lock);

      return ret;
}

EXPORT_SYMBOL(clk_get);
EXPORT_SYMBOL(clk_put);
EXPORT_SYMBOL(clk_enable);
EXPORT_SYMBOL(clk_disable);
EXPORT_SYMBOL(clk_get_rate);
EXPORT_SYMBOL(clk_round_rate);
EXPORT_SYMBOL(clk_set_rate);
EXPORT_SYMBOL(clk_get_parent);
EXPORT_SYMBOL(clk_set_parent);

/* base clocks */

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

struct clk clk_xtal = {
      .name       = "xtal",
      .id         = -1,
      .rate       = 0,
      .parent           = NULL,
      .ctrlbit    = 0,
};

struct clk clk_ext = {
      .name       = "ext",
      .id         = -1,
};

struct clk clk_epll = {
      .name       = "epll",
      .id         = -1,
};

struct clk clk_mpll = {
      .name       = "mpll",
      .id         = -1,
      .set_rate   = clk_default_setrate,
};

struct clk clk_upll = {
      .name       = "upll",
      .id         = -1,
      .parent           = NULL,
      .ctrlbit    = 0,
};

struct clk clk_f = {
      .name       = "fclk",
      .id         = -1,
      .rate       = 0,
      .parent           = &clk_mpll,
      .ctrlbit    = 0,
      .set_rate   = clk_default_setrate,
};

struct clk clk_h = {
      .name       = "hclk",
      .id         = -1,
      .rate       = 0,
      .parent           = NULL,
      .ctrlbit    = 0,
      .set_rate   = clk_default_setrate,
};

struct clk clk_p = {
      .name       = "pclk",
      .id         = -1,
      .rate       = 0,
      .parent           = NULL,
      .ctrlbit    = 0,
      .set_rate   = clk_default_setrate,
};

struct clk clk_usb_bus = {
      .name       = "usb-bus",
      .id         = -1,
      .rate       = 0,
      .parent           = &clk_upll,
};



struct clk s3c24xx_uclk = {
      .name       = "uclk",
      .id         = -1,
};

/* initialise the clock system */

int s3c24xx_register_clock(struct clk *clk)
{
      if (clk->enable == NULL)
            clk->enable = clk_null_enable;

      /* add to the list of available clocks */

      /* Quick check to see if this clock has already been registered. */
      BUG_ON(clk->list.prev != clk->list.next);

      spin_lock(&clocks_lock);
      list_add(&clk->list, &clocks);
      spin_unlock(&clocks_lock);

      return 0;
}

int s3c24xx_register_clocks(struct clk **clks, int nr_clks)
{
      int fails = 0;

      for (; nr_clks > 0; nr_clks--, clks++) {
            if (s3c24xx_register_clock(*clks) < 0)
                  fails++;
      }

      return fails;
}

/* initalise all the clocks */

int __init s3c24xx_register_baseclocks(unsigned long xtal)
{
      printk(KERN_INFO "S3C24XX Clocks, (c) 2004 Simtec Electronics\n");

      clk_xtal.rate = xtal;

      /* register our clocks */

      if (s3c24xx_register_clock(&clk_xtal) < 0)
            printk(KERN_ERR "failed to register master xtal\n");

      if (s3c24xx_register_clock(&clk_mpll) < 0)
            printk(KERN_ERR "failed to register mpll clock\n");

      if (s3c24xx_register_clock(&clk_upll) < 0)
            printk(KERN_ERR "failed to register upll clock\n");

      if (s3c24xx_register_clock(&clk_f) < 0)
            printk(KERN_ERR "failed to register cpu fclk\n");

      if (s3c24xx_register_clock(&clk_h) < 0)
            printk(KERN_ERR "failed to register cpu hclk\n");

      if (s3c24xx_register_clock(&clk_p) < 0)
            printk(KERN_ERR "failed to register cpu pclk\n");

      return 0;
}


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