blob: fc97fe57ee6feeb473ca4e178251db5c50b32617 [file] [log] [blame]
Russell King97d654f2006-03-15 15:54:37 +00001/*
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>
Russell Kingd0a9d752007-04-22 10:08:58 +010012#include <linux/mutex.h>
Russell King97d654f2006-03-15 15:54:37 +000013
14#include <asm/hardware.h>
Russell King97d654f2006-03-15 15:54:37 +000015
Russell Kingd0a9d752007-04-22 10:08:58 +010016/*
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 */
Russell King97d654f2006-03-15 15:54:37 +000020struct clk {
21 struct list_head node;
22 unsigned long rate;
Russell King97d654f2006-03-15 15:54:37 +000023 const char *name;
24 unsigned int enabled;
25 void (*enable)(void);
26 void (*disable)(void);
27};
28
29static LIST_HEAD(clocks);
Russell Kingd0a9d752007-04-22 10:08:58 +010030static DEFINE_MUTEX(clocks_mutex);
Russell King97d654f2006-03-15 15:54:37 +000031static DEFINE_SPINLOCK(clocks_lock);
32
33struct clk *clk_get(struct device *dev, const char *id)
34{
35 struct clk *p, *clk = ERR_PTR(-ENOENT);
36
Russell Kingd0a9d752007-04-22 10:08:58 +010037 mutex_lock(&clocks_mutex);
Russell King97d654f2006-03-15 15:54:37 +000038 list_for_each_entry(p, &clocks, node) {
Russell Kingd0a9d752007-04-22 10:08:58 +010039 if (strcmp(id, p->name) == 0) {
Russell King97d654f2006-03-15 15:54:37 +000040 clk = p;
41 break;
42 }
43 }
Russell Kingd0a9d752007-04-22 10:08:58 +010044 mutex_unlock(&clocks_mutex);
Russell King97d654f2006-03-15 15:54:37 +000045
46 return clk;
47}
48EXPORT_SYMBOL(clk_get);
49
50void clk_put(struct clk *clk)
51{
Russell King97d654f2006-03-15 15:54:37 +000052}
53EXPORT_SYMBOL(clk_put);
54
55int 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}
65EXPORT_SYMBOL(clk_enable);
66
67void 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}
78EXPORT_SYMBOL(clk_disable);
79
80unsigned long clk_get_rate(struct clk *clk)
81{
82 return clk->rate;
83}
84EXPORT_SYMBOL(clk_get_rate);
85
86
87static 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
98static void clk_gpio27_disable(void)
99{
100 TUCR = 0;
101 GPDR &= ~GPIO_32_768kHz;
102 GAFR &= ~GPIO_32_768kHz;
103}
104
105static struct clk clk_gpio27 = {
106 .name = "GPIO27_CLK",
107 .rate = 3686400,
108 .enable = clk_gpio27_enable,
109 .disable = clk_gpio27_disable,
110};
111
112int clk_register(struct clk *clk)
113{
Russell Kingd0a9d752007-04-22 10:08:58 +0100114 mutex_lock(&clocks_mutex);
Russell King97d654f2006-03-15 15:54:37 +0000115 list_add(&clk->node, &clocks);
Russell Kingd0a9d752007-04-22 10:08:58 +0100116 mutex_unlock(&clocks_mutex);
Russell King97d654f2006-03-15 15:54:37 +0000117 return 0;
118}
119EXPORT_SYMBOL(clk_register);
120
121void clk_unregister(struct clk *clk)
122{
Russell Kingd0a9d752007-04-22 10:08:58 +0100123 mutex_lock(&clocks_mutex);
Russell King97d654f2006-03-15 15:54:37 +0000124 list_del(&clk->node);
Russell Kingd0a9d752007-04-22 10:08:58 +0100125 mutex_unlock(&clocks_mutex);
Russell King97d654f2006-03-15 15:54:37 +0000126}
127EXPORT_SYMBOL(clk_unregister);
128
129static int __init clk_init(void)
130{
131 clk_register(&clk_gpio27);
132 return 0;
133}
134arch_initcall(clk_init);