arch/arm/mach-pxa/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/list.h>
   7 #include <linux/errno.h>
   8 #include <linux/err.h>
   9 #include <linux/string.h>
  10 #include <linux/clk.h>
  11 #include <linux/spinlock.h>
  12
  13 #include <asm/arch/pxa-regs.h>
  14 #include <asm/hardware.h>
  15 #include <asm/semaphore.h>
  16
  17 struct clk {
  18         struct list_head        node;
  19         unsigned long           rate;
  20         struct module           *owner;
  21         const char              *name;
  22         unsigned int            enabled;
  23         void                    (*enable)(void);
  24         void                    (*disable)(void);
  25 };
  26
  27 static LIST_HEAD(clocks);
  28 static DECLARE_MUTEX(clocks_sem);
  29 static DEFINE_SPINLOCK(clocks_lock);
  30
  31 struct clk *clk_get(struct device *dev, const char *id)
  32 {
  33         struct clk *p, *clk = ERR_PTR(-ENOENT);
  34
  35         down(&clocks_sem);
  36         list_for_each_entry(p, &clocks, node) {
  37                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
  38                         clk = p;
  39                         break;
  40                 }
  41         }
  42         up(&clocks_sem);
  43
  44         return clk;
  45 }
  46 EXPORT_SYMBOL(clk_get);
  47
  48 void clk_put(struct clk *clk)
  49 {
  50         module_put(clk->owner);
  51 }
  52 EXPORT_SYMBOL(clk_put);
  53
  54 int clk_enable(struct clk *clk)
  55 {
  56         unsigned long flags;
  57
  58         spin_lock_irqsave(&clocks_lock, flags);
  59         if (clk->enabled++ == 0)
  60                 clk->enable();
  61         spin_unlock_irqrestore(&clocks_lock, flags);
  62         return 0;
  63 }
  64 EXPORT_SYMBOL(clk_enable);
  65
  66 void clk_disable(struct clk *clk)
  67 {
  68         unsigned long flags;
  69
  70         WARN_ON(clk->enabled == 0);
  71
  72         spin_lock_irqsave(&clocks_lock, flags);
  73         if (--clk->enabled == 0)
  74                 clk->disable();
  75         spin_unlock_irqrestore(&clocks_lock, flags);
  76 }
  77 EXPORT_SYMBOL(clk_disable);
  78
  79 unsigned long clk_get_rate(struct clk *clk)
  80 {
  81         return clk->rate;
  82 }
  83 EXPORT_SYMBOL(clk_get_rate);
  84
  85
  86 static void clk_gpio27_enable(void)
  87 {
  88         pxa_gpio_mode(GPIO11_3_6MHz_MD);
  89 }
  90
  91 static void clk_gpio27_disable(void)
  92 {
  93 }
  94
  95 static struct clk clk_gpio27 = {
  96         .name           = "GPIO27_CLK",
  97         .rate           = 3686400,
  98         .enable         = clk_gpio27_enable,
  99         .disable        = clk_gpio27_disable,
 100 };
 101
 102 int clk_register(struct clk *clk)
 103 {
 104         down(&clocks_sem);
 105         list_add(&clk->node, &clocks);
 106         up(&clocks_sem);
 107         return 0;
 108 }
 109 EXPORT_SYMBOL(clk_register);
 110
 111 void clk_unregister(struct clk *clk)
 112 {
 113         down(&clocks_sem);
 114         list_del(&clk->node);
 115         up(&clocks_sem);
 116 }
 117 EXPORT_SYMBOL(clk_unregister);
 118
 119 static int __init clk_init(void)
 120 {
 121         clk_register(&clk_gpio27);
 122         return 0;
 123 }
 124 arch_initcall(clk_init);