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 #include <linux/mutex.h>
13
14 #include <asm/hardware.h>
15
16 /*
17 * Very simple clock implementation - we only have one clock to
18 * deal with at the moment, so we only match using the "name".
19 */
20 struct clk {
21 struct list_head node;
22 unsigned long rate;
23 const char *name;
24 unsigned int enabled;
25 void (*enable)(void);
26 void (*disable)(void);
27 };
28
29 static LIST_HEAD(clocks);
30 static DEFINE_MUTEX(clocks_mutex);
31 static DEFINE_SPINLOCK(clocks_lock);
32
33 struct clk *clk_get(struct device *dev, const char *id)
34 {
35 struct clk *p, *clk = ERR_PTR(-ENOENT);
36
37 mutex_lock(&clocks_mutex);
38 list_for_each_entry(p, &clocks, node) {
39 if (strcmp(id, p->name) == 0) {
40 clk = p;
41 break;
42 }
43 }
44 mutex_unlock(&clocks_mutex);
45
46 return clk;
47 }
48 EXPORT_SYMBOL(clk_get);
49
50 void clk_put(struct clk *clk)
51 {
52 }
53 EXPORT_SYMBOL(clk_put);
54
55 int clk_enable(struct clk *clk)
56 {
57 unsigned long flags;
58
59 spin_lock_irqsave(&clocks_lock, flags);
60 if (clk->enabled++ == 0)
61 clk->enable();
62 spin_unlock_irqrestore(&clocks_lock, flags);
63 return 0;
64 }
65 EXPORT_SYMBOL(clk_enable);
66
67 void clk_disable(struct clk *clk)
68 {
69 unsigned long flags;
70
71 WARN_ON(clk->enabled == 0);
72
73 spin_lock_irqsave(&clocks_lock, flags);
74 if (--clk->enabled == 0)
75 clk->disable();
76 spin_unlock_irqrestore(&clocks_lock, flags);
77 }
78 EXPORT_SYMBOL(clk_disable);
79
80 unsigned long clk_get_rate(struct clk *clk)
81 {
82 return clk->rate;
83 }
84 EXPORT_SYMBOL(clk_get_rate);
85
86
87 static void clk_gpio27_enable(void)
88 {
89 /*
90 * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111:
91 * (SA-1110 Developer's Manual, section 9.1.2.1)
92 */
93 GAFR |= GPIO_32_768kHz;
94 GPDR |= GPIO_32_768kHz;
95 TUCR = TUCR_3_6864MHz;
96 }
97
98 static void clk_gpio27_disable(void)
99 {
100 TUCR = 0;
101 GPDR &= ~GPIO_32_768kHz;
102 GAFR &= ~GPIO_32_768kHz;
103 }
104
105 static struct clk clk_gpio27 = {
106 .name = "GPIO27_CLK",
107 .rate = 3686400,
108 .enable = clk_gpio27_enable,
109 .disable = clk_gpio27_disable,
110 };
111
112 int clk_register(struct clk *clk)
113 {
114 mutex_lock(&clocks_mutex);
115 list_add(&clk->node, &clocks);
116 mutex_unlock(&clocks_mutex);
117 return 0;
118 }
119 EXPORT_SYMBOL(clk_register);
120
121 void clk_unregister(struct clk *clk)
122 {
123 mutex_lock(&clocks_mutex);
124 list_del(&clk->node);
125 mutex_unlock(&clocks_mutex);
126 }
127 EXPORT_SYMBOL(clk_unregister);
128
129 static int __init clk_init(void)
130 {
131 clk_register(&clk_gpio27);
132 return 0;
133 }
134 arch_initcall(clk_init);
135
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