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clksel.c

/*
 * linux/arch/arm/mach-w90x900/clksel.c
 *
 * Copyright (c) 2008 Nuvoton technology corporation
 *
 * Wan ZongShun <mcuos.com@gmail.com>
 *
 * 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;version 2 of the License.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.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/io.h>

#include <mach/hardware.h>
#include <mach/regs-clock.h>

#define PLL0            0x00
#define PLL1            0x01
#define OTHER           0x02
#define EXT       0x03
#define MSOFFSET  0x0C
#define ATAOFFSET 0x0a
#define LCDOFFSET 0x06
#define AUDOFFSET 0x04
#define CPUOFFSET 0x00

static DEFINE_MUTEX(clksel_sem);

static void clock_source_select(const char *dev_id, unsigned int clkval)
{
      unsigned int clksel, offset;

      clksel = __raw_readl(REG_CLKSEL);

      if (strcmp(dev_id, "nuc900-ms") == 0)
            offset = MSOFFSET;
      else if (strcmp(dev_id, "nuc900-atapi") == 0)
            offset = ATAOFFSET;
      else if (strcmp(dev_id, "nuc900-lcd") == 0)
            offset = LCDOFFSET;
      else if (strcmp(dev_id, "nuc900-audio") == 0)
            offset = AUDOFFSET;
      else
            offset = CPUOFFSET;

      clksel &= ~(0x03 << offset);
      clksel |= (clkval << offset);

      __raw_writel(clksel, REG_CLKSEL);
}

void nuc900_clock_source(struct device *dev, unsigned char *src)
{
      unsigned int clkval;
      const char *dev_id;

      BUG_ON(!src);
      clkval = 0;

      mutex_lock(&clksel_sem);

      if (dev)
            dev_id = dev_name(dev);
      else
            dev_id = "cpufreq";

      if (strcmp(src, "pll0") == 0)
            clkval = PLL0;
      else if (strcmp(src, "pll1") == 0)
            clkval = PLL1;
      else if (strcmp(src, "ext") == 0)
            clkval = EXT;
      else if (strcmp(src, "oth") == 0)
            clkval = OTHER;

      clock_source_select(dev_id, clkval);

      mutex_unlock(&clksel_sem);
}
EXPORT_SYMBOL(nuc900_clock_source);


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