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 /* Dummy clk routine to build generic kernel parts that may be using them */
  37 unsigned long clk_get_rate(struct clk *clk)
  38 {
  39         return 0;
  40 }
  41 EXPORT_SYMBOL(clk_get_rate);
  42
  43 static void clk_gpio27_enable(struct clk *clk)
  44 {
  45         /*
  46          * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111:
  47          * (SA-1110 Developer's Manual, section 9.1.2.1)
  48          */
  49         GAFR |= GPIO_32_768kHz;
  50         GPDR |= GPIO_32_768kHz;
  51         TUCR = TUCR_3_6864MHz;
  52 }
  53
  54 static void clk_gpio27_disable(struct clk *clk)
  55 {
  56         TUCR = 0;
  57         GPDR &= ~GPIO_32_768kHz;
  58         GAFR &= ~GPIO_32_768kHz;
  59 }
  60
  61 int clk_enable(struct clk *clk)
  62 {
  63         unsigned long flags;
  64
  65         if (clk) {
  66                 spin_lock_irqsave(&clocks_lock, flags);
  67                 if (clk->enabled++ == 0)
  68                         clk->ops->enable(clk);
  69                 spin_unlock_irqrestore(&clocks_lock, flags);
  70         }
  71
  72         return 0;
  73 }
  74 EXPORT_SYMBOL(clk_enable);
  75
  76 void clk_disable(struct clk *clk)
  77 {
  78         unsigned long flags;
  79
  80         if (clk) {
  81                 WARN_ON(clk->enabled == 0);
  82                 spin_lock_irqsave(&clocks_lock, flags);
  83                 if (--clk->enabled == 0)
  84                         clk->ops->disable(clk);
  85                 spin_unlock_irqrestore(&clocks_lock, flags);
  86         }
  87 }
  88 EXPORT_SYMBOL(clk_disable);
  89
  90 const struct clkops clk_gpio27_ops = {
  91         .enable         = clk_gpio27_enable,
  92         .disable        = clk_gpio27_disable,
  93 };
  94
  95 static DEFINE_CLK(gpio27, &clk_gpio27_ops);
  96
  97 static struct clk_lookup sa11xx_clkregs[] = {
  98         CLKDEV_INIT("sa1111.0", NULL, &clk_gpio27),
  99         CLKDEV_INIT("sa1100-rtc", NULL, NULL),
 100 };
 101
 102 static int __init sa11xx_clk_init(void)
 103 {
 104         clkdev_add_table(sa11xx_clkregs, ARRAY_SIZE(sa11xx_clkregs));
 105         return 0;
 106 }
 107 core_initcall(sa11xx_clk_init);