clock.c

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/*
 *  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 *);
};

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;
}

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);

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

static DEFINE_CLK(gpio27, &clk_gpio27_ops);

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

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