1. 根目录:
2. arch
3. arm
4. mach-sa1100
5. clock.c

/*
 *  linux/arch/arm/mach-sa1100/clock.c
 */
#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/spinlock.h>
#include <linux/mutex.h>
#include <linux/io.h>
#include <linux/clkdev.h>

#include <mach/hardware.h>
#include <mach/generic.h>

struct clkops {
	void			(*enable)(struct clk *);
	void			(*disable)(struct clk *);
	unsigned long		(*get_rate)(struct clk *);
};

struct clk {
	const struct clkops	*ops;
	unsigned int		enabled;
};

#define DEFINE_CLK(_name, _ops)				\
struct clk clk_##_name = {				\
		.ops	= _ops,				\
	}

static DEFINE_SPINLOCK(clocks_lock);

static void clk_gpio27_enable(struct clk *clk)
{
	/*
	 * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111:
	 * (SA-1110 Developer's Manual, section 9.1.2.1)
	 */
	GAFR |= GPIO_32_768kHz;
	GPDR |= GPIO_32_768kHz;
	TUCR = TUCR_3_6864MHz;
}

static void clk_gpio27_disable(struct clk *clk)
{
	TUCR = 0;
	GPDR &= ~GPIO_32_768kHz;
	GAFR &= ~GPIO_32_768kHz;
}

static void clk_cpu_enable(struct clk *clk)
{
}

static void clk_cpu_disable(struct clk *clk)
{
}

static unsigned long clk_cpu_get_rate(struct clk *clk)
{
	return sa11x0_getspeed(0) * 1000;
}

int clk_enable(struct clk *clk)
{
	unsigned long flags;

	if (clk) {
		spin_lock_irqsave(&clocks_lock, flags);
		if (clk->enabled++ == 0)
			clk->ops->enable(clk);
		spin_unlock_irqrestore(&clocks_lock, flags);
	}

	return 0;
}
EXPORT_SYMBOL(clk_enable);

void clk_disable(struct clk *clk)
{
	unsigned long flags;

	if (clk) {
		WARN_ON(clk->enabled == 0);
		spin_lock_irqsave(&clocks_lock, flags);
		if (--clk->enabled == 0)
			clk->ops->disable(clk);
		spin_unlock_irqrestore(&clocks_lock, flags);
	}
}
EXPORT_SYMBOL(clk_disable);

unsigned long clk_get_rate(struct clk *clk)
{
	if (clk && clk->ops && clk->ops->get_rate)
		return clk->ops->get_rate(clk);

	return 0;
}
EXPORT_SYMBOL(clk_get_rate);

const struct clkops clk_gpio27_ops = {
	.enable		= clk_gpio27_enable,
	.disable	= clk_gpio27_disable,
};

const struct clkops clk_cpu_ops = {
	.enable		= clk_cpu_enable,
	.disable	= clk_cpu_disable,
	.get_rate	= clk_cpu_get_rate,
};

static DEFINE_CLK(gpio27, &clk_gpio27_ops);

static DEFINE_CLK(cpu, &clk_cpu_ops);

static unsigned long clk_36864_get_rate(struct clk *clk)
{
	return 3686400;
}

static struct clkops clk_36864_ops = {
	.get_rate	= clk_36864_get_rate,
};

static DEFINE_CLK(36864, &clk_36864_ops);

static struct clk_lookup sa11xx_clkregs[] = {
	CLKDEV_INIT("sa1111.0", NULL, &clk_gpio27),
	CLKDEV_INIT("sa1100-rtc", NULL, NULL),
	CLKDEV_INIT("sa11x0-fb", NULL, &clk_cpu),
	CLKDEV_INIT("sa11x0-pcmcia", NULL, &clk_cpu),
	/* sa1111 names devices using internal offsets, PCMCIA is at 0x1800 */
	CLKDEV_INIT("1800", NULL, &clk_cpu),
	CLKDEV_INIT(NULL, "OSTIMER0", &clk_36864),
};

static int __init sa11xx_clk_init(void)
{
	clkdev_add_table(sa11xx_clkregs, ARRAY_SIZE(sa11xx_clkregs));
	return 0;
}
core_initcall(sa11xx_clk_init);