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s3c244x-clock.c

/* linux/arch/arm/plat-s3c24xx/s3c24xx-clock.c
 *
 * Copyright (c) 2004-2005,2008 Simtec Electronics
 *    http://armlinux.simtec.co.uk/
 *    Ben Dooks <ben@simtec.co.uk>
 *
 * S3C2440/S3C2442 Common clock support
 *
 * 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/device.h>
#include <linux/sysdev.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/mutex.h>
#include <linux/clk.h>
#include <linux/io.h>

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

#include <mach/regs-clock.h>

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

static int s3c2440_setparent_armclk(struct clk *clk, struct clk *parent)
{
      unsigned long camdivn;
      unsigned long dvs;

      if (parent == &clk_f)
            dvs = 0;
      else if (parent == &clk_h)
            dvs = S3C2440_CAMDIVN_DVSEN;
      else
            return -EINVAL;

      clk->parent = parent;

      camdivn  = __raw_readl(S3C2440_CAMDIVN);
      camdivn &= ~S3C2440_CAMDIVN_DVSEN;
      camdivn |= dvs;
      __raw_writel(camdivn, S3C2440_CAMDIVN);

      return 0;
}

static struct clk clk_arm = {
      .name       = "armclk",
      .id         = -1,
      .set_parent = s3c2440_setparent_armclk,
};

static int s3c244x_clk_add(struct sys_device *sysdev)
{
      unsigned long camdivn = __raw_readl(S3C2440_CAMDIVN);
      unsigned long clkdivn;
      struct clk *clock_upll;
      int ret;

      printk("S3C244X: Clock Support, DVS %s\n",
             (camdivn & S3C2440_CAMDIVN_DVSEN) ? "on" : "off");

      clk_arm.parent = (camdivn & S3C2440_CAMDIVN_DVSEN) ? &clk_h : &clk_f;

      ret = s3c24xx_register_clock(&clk_arm);
      if (ret < 0) {
            printk(KERN_ERR "S3C24XX: Failed to add armclk (%d)\n", ret);
            return ret;
      }

      clock_upll = clk_get(NULL, "upll");
      if (IS_ERR(clock_upll)) {
            printk(KERN_ERR "S3C244X: Failed to get upll clock\n");
            return -ENOENT;
      }

      /* check rate of UPLL, and if it is near 96MHz, then change
       * to using half the UPLL rate for the system */

      if (clk_get_rate(clock_upll) > (94 * MHZ)) {
            clk_usb_bus.rate = clk_get_rate(clock_upll) / 2;

            mutex_lock(&clocks_mutex);

            clkdivn = __raw_readl(S3C2410_CLKDIVN);
            clkdivn |= S3C2440_CLKDIVN_UCLK;
            __raw_writel(clkdivn, S3C2410_CLKDIVN);

            mutex_unlock(&clocks_mutex);
      }

      return 0;
}

static struct sysdev_driver s3c2440_clk_driver = {
      .add        = s3c244x_clk_add,
};

static int s3c2440_clk_init(void)
{
      return sysdev_driver_register(&s3c2440_sysclass, &s3c2440_clk_driver);
}

arch_initcall(s3c2440_clk_init);

static struct sysdev_driver s3c2442_clk_driver = {
      .add        = s3c244x_clk_add,
};

static int s3c2442_clk_init(void)
{
      return sysdev_driver_register(&s3c2442_sysclass, &s3c2442_clk_driver);
}

arch_initcall(s3c2442_clk_init);

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