clksel.c
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/*
* 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-ac97") == 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);