Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq
[linux-2.6] / 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/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/hardware.h>
14 #include <asm/semaphore.h>
15
16 struct clk {
17         struct list_head        node;
18         unsigned long           rate;
19         struct module           *owner;
20         const char              *name;
21         unsigned int            enabled;
22         void                    (*enable)(void);
23         void                    (*disable)(void);
24 };
25
26 static LIST_HEAD(clocks);
27 static DECLARE_MUTEX(clocks_sem);
28 static DEFINE_SPINLOCK(clocks_lock);
29
30 struct clk *clk_get(struct device *dev, const char *id)
31 {
32         struct clk *p, *clk = ERR_PTR(-ENOENT);
33
34         down(&clocks_sem);
35         list_for_each_entry(p, &clocks, node) {
36                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
37                         clk = p;
38                         break;
39                 }
40         }
41         up(&clocks_sem);
42
43         return clk;
44 }
45 EXPORT_SYMBOL(clk_get);
46
47 void clk_put(struct clk *clk)
48 {
49         module_put(clk->owner);
50 }
51 EXPORT_SYMBOL(clk_put);
52
53 int clk_enable(struct clk *clk)
54 {
55         unsigned long flags;
56
57         spin_lock_irqsave(&clocks_lock, flags);
58         if (clk->enabled++ == 0)
59                 clk->enable();
60         spin_unlock_irqrestore(&clocks_lock, flags);
61         return 0;
62 }
63 EXPORT_SYMBOL(clk_enable);
64
65 void clk_disable(struct clk *clk)
66 {
67         unsigned long flags;
68
69         WARN_ON(clk->enabled == 0);
70
71         spin_lock_irqsave(&clocks_lock, flags);
72         if (--clk->enabled == 0)
73                 clk->disable();
74         spin_unlock_irqrestore(&clocks_lock, flags);
75 }
76 EXPORT_SYMBOL(clk_disable);
77
78 unsigned long clk_get_rate(struct clk *clk)
79 {
80         return clk->rate;
81 }
82 EXPORT_SYMBOL(clk_get_rate);
83
84
85 static void clk_gpio27_enable(void)
86 {
87         /*
88          * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111:
89          * (SA-1110 Developer's Manual, section 9.1.2.1)
90          */
91         GAFR |= GPIO_32_768kHz;
92         GPDR |= GPIO_32_768kHz;
93         TUCR = TUCR_3_6864MHz;
94 }
95
96 static void clk_gpio27_disable(void)
97 {
98         TUCR = 0;
99         GPDR &= ~GPIO_32_768kHz;
100         GAFR &= ~GPIO_32_768kHz;
101 }
102
103 static struct clk clk_gpio27 = {
104         .name           = "GPIO27_CLK",
105         .rate           = 3686400,
106         .enable         = clk_gpio27_enable,
107         .disable        = clk_gpio27_disable,
108 };
109
110 int clk_register(struct clk *clk)
111 {
112         down(&clocks_sem);
113         list_add(&clk->node, &clocks);
114         up(&clocks_sem);
115         return 0;
116 }
117 EXPORT_SYMBOL(clk_register);
118
119 void clk_unregister(struct clk *clk)
120 {
121         down(&clocks_sem);
122         list_del(&clk->node);
123         up(&clocks_sem);
124 }
125 EXPORT_SYMBOL(clk_unregister);
126
127 static int __init clk_init(void)
128 {
129         clk_register(&clk_gpio27);
130         return 0;
131 }
132 arch_initcall(clk_init);