arch/arm/mach-sa1100/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>

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

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

#define INIT_CLKREG(_clk, _devname, _conname)		\
	{						\
		.clk		= _clk,			\
		.dev_id		= _devname,		\
		.con_id		= _conname,		\
	}

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

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;
}

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

	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;

	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)
{
	unsigned long rate;

	rate = clk->rate;
	if (clk->ops->getrate)
		rate = clk->ops->getrate(clk);

	return rate;
}
EXPORT_SYMBOL(clk_get_rate);

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

static void clk_dummy_enable(struct clk *clk) { }
static void clk_dummy_disable(struct clk *clk) { }

const struct clkops clk_dummy_ops = {
	.enable		= clk_dummy_enable,
	.disable	= clk_dummy_disable,
};

static DEFINE_CLK(gpio27, &clk_gpio27_ops, 3686400);
static DEFINE_CLK(dummy, &clk_dummy_ops, 0);

static struct clk_lookup sa11xx_clkregs[] = {
	INIT_CLKREG(&clk_gpio27, "sa1111.0", NULL),
	INIT_CLKREG(&clk_dummy, "sa1100-rtc", NULL),
};

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

postcore_initcall(sa11xx_clk_init);