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Sourcecode: linux-2.6 version File versions

clock.c

/*
 *  linux/arch/arm/mach-sa1100/clock.c
 */
#include <linux/module.h>
#include <linux/kernel.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 <asm/hardware.h>

/*
 * Very simple clock implementation - we only have one clock to
 * deal with at the moment, so we only match using the "name".
 */
struct clk {
      struct list_head  node;
      unsigned long           rate;
      const char        *name;
      unsigned int            enabled;
      void              (*enable)(void);
      void              (*disable)(void);
};

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);
static DEFINE_SPINLOCK(clocks_lock);

struct clk *clk_get(struct device *dev, const char *id)
{
      struct clk *p, *clk = ERR_PTR(-ENOENT);

      mutex_lock(&clocks_mutex);
      list_for_each_entry(p, &clocks, node) {
            if (strcmp(id, p->name) == 0) {
                  clk = p;
                  break;
            }
      }
      mutex_unlock(&clocks_mutex);

      return clk;
}
EXPORT_SYMBOL(clk_get);

void clk_put(struct clk *clk)
{
}
EXPORT_SYMBOL(clk_put);

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

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

unsigned long clk_get_rate(struct clk *clk)
{
      return clk->rate;
}
EXPORT_SYMBOL(clk_get_rate);


static void clk_gpio27_enable(void)
{
      /*
       * 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(void)
{
      TUCR = 0;
      GPDR &= ~GPIO_32_768kHz;
      GAFR &= ~GPIO_32_768kHz;
}

static struct clk clk_gpio27 = {
      .name       = "GPIO27_CLK",
      .rate       = 3686400,
      .enable           = clk_gpio27_enable,
      .disable    = clk_gpio27_disable,
};

int clk_register(struct clk *clk)
{
      mutex_lock(&clocks_mutex);
      list_add(&clk->node, &clocks);
      mutex_unlock(&clocks_mutex);
      return 0;
}
EXPORT_SYMBOL(clk_register);

void clk_unregister(struct clk *clk)
{
      mutex_lock(&clocks_mutex);
      list_del(&clk->node);
      mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_unregister);

static int __init clk_init(void)
{
      clk_register(&clk_gpio27);
      return 0;
}
arch_initcall(clk_init);

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