LXR linux/arch/arm/mach-sa1100/clock.c

   1/*
   2 *  linux/arch/arm/mach-sa1100/clock.c
   3 */
   4#include <linux/module.h>
   5#include <linux/kernel.h>
   6#include <linux/device.h>
   7#include <linux/list.h>
   8#include <linux/errno.h>
   9#include <linux/err.h>
  10#include <linux/string.h>
  11#include <linux/clk.h>
  12#include <linux/spinlock.h>
  13#include <linux/mutex.h>
  14
  15#include <mach/hardware.h>
  16
  17/*
  18 * Very simple clock implementation - we only have one clock to deal with.
  19 */
  20struct clk {
  21        unsigned int            enabled;
  22};
  23
  24static void clk_gpio27_enable(void)
  25{
  26        /*
  27         * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111:
  28         * (SA-1110 Developer's Manual, section 9.1.2.1)
  29         */
  30        GAFR |= GPIO_32_768kHz;
  31        GPDR |= GPIO_32_768kHz;
  32        TUCR = TUCR_3_6864MHz;
  33}
  34
  35static void clk_gpio27_disable(void)
  36{
  37        TUCR = 0;
  38        GPDR &= ~GPIO_32_768kHz;
  39        GAFR &= ~GPIO_32_768kHz;
  40}
  41
  42static struct clk clk_gpio27;
  43
  44static DEFINE_SPINLOCK(clocks_lock);
  45
  46struct clk *clk_get(struct device *dev, const char *id)
  47{
  48        const char *devname = dev_name(dev);
  49
  50        return strcmp(devname, "sa1111.0") ? ERR_PTR(-ENOENT) : &clk_gpio27;
  51}
  52EXPORT_SYMBOL(clk_get);
  53
  54void clk_put(struct clk *clk)
  55{
  56}
  57EXPORT_SYMBOL(clk_put);
  58
  59int clk_enable(struct clk *clk)
  60{
  61        unsigned long flags;
  62
  63        spin_lock_irqsave(&clocks_lock, flags);
  64        if (clk->enabled++ == 0)
  65                clk_gpio27_enable();
  66        spin_unlock_irqrestore(&clocks_lock, flags);
  67        return 0;
  68}
  69EXPORT_SYMBOL(clk_enable);
  70
  71void clk_disable(struct clk *clk)
  72{
  73        unsigned long flags;
  74
  75        WARN_ON(clk->enabled == 0);
  76
  77        spin_lock_irqsave(&clocks_lock, flags);
  78        if (--clk->enabled == 0)
  79                clk_gpio27_disable();
  80        spin_unlock_irqrestore(&clocks_lock, flags);
  81}
  82EXPORT_SYMBOL(clk_disable);
  83
  84unsigned long clk_get_rate(struct clk *clk)
  85{
  86        return 3686400;
  87}
  88EXPORT_SYMBOL(clk_get_rate);
  89