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 #include <linux/io.h>
  15 #include <linux/clkdev.h>
  16
  17 #include <mach/hardware.h>
  18
  19 struct clkops {
  20         void                    (*enable)(struct clk *);
  21         void                    (*disable)(struct clk *);
  22 };
  23
  24 struct clk {
  25         const struct clkops     *ops;
  26         unsigned int            enabled;
  27 };
  28
  29 #define DEFINE_CLK(_name, _ops)                         \
  30 struct clk clk_##_name = {                              \
  31                 .ops    = _ops,                         \
  32         }
  33
  34 static DEFINE_SPINLOCK(clocks_lock);
  35
  36 static void clk_gpio27_enable(struct clk *clk)
  37 {
  38         /*
  39          * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111:
  40          * (SA-1110 Developer's Manual, section 9.1.2.1)
  41          */
  42         GAFR |= GPIO_32_768kHz;
  43         GPDR |= GPIO_32_768kHz;
  44         TUCR = TUCR_3_6864MHz;
  45 }
  46
  47 static void clk_gpio27_disable(struct clk *clk)
  48 {
  49         TUCR = 0;
  50         GPDR &= ~GPIO_32_768kHz;
  51         GAFR &= ~GPIO_32_768kHz;
  52 }
  53
  54 int clk_enable(struct clk *clk)
  55 {
  56         unsigned long flags;
  57
  58         if (clk) {
  59                 spin_lock_irqsave(&clocks_lock, flags);
  60                 if (clk->enabled++ == 0)
  61                         clk->ops->enable(clk);
  62                 spin_unlock_irqrestore(&clocks_lock, flags);
  63         }
  64
  65         return 0;
  66 }
  67 EXPORT_SYMBOL(clk_enable);
  68
  69 void clk_disable(struct clk *clk)
  70 {
  71         unsigned long flags;
  72
  73         if (clk) {
  74                 WARN_ON(clk->enabled == 0);
  75                 spin_lock_irqsave(&clocks_lock, flags);
  76                 if (--clk->enabled == 0)
  77                         clk->ops->disable(clk);
  78                 spin_unlock_irqrestore(&clocks_lock, flags);
  79         }
  80 }
  81 EXPORT_SYMBOL(clk_disable);
  82
  83 const struct clkops clk_gpio27_ops = {
  84         .enable         = clk_gpio27_enable,
  85         .disable        = clk_gpio27_disable,
  86 };
  87
  88 static DEFINE_CLK(gpio27, &clk_gpio27_ops);
  89
  90 static struct clk_lookup sa11xx_clkregs[] = {
  91         CLKDEV_INIT("sa1111.0", NULL, &clk_gpio27),
  92         CLKDEV_INIT("sa1100-rtc", NULL, NULL),
  93 };
  94
  95 static int __init sa11xx_clk_init(void)
  96 {
  97         clkdev_add_table(sa11xx_clkregs, ARRAY_SIZE(sa11xx_clkregs));
  98         return 0;
  99 }
 100 core_initcall(sa11xx_clk_init);