[ARM] 5590/1: Add basic support for ST Nomadik 8815 SoC and evaluation board
[deliverable/linux.git] / arch / arm / mach-ns9xxx / clock.c
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1/*
2 * arch/arm/mach-ns9xxx/clock.c
3 *
4 * Copyright (C) 2007 by Digi International Inc.
5 * All rights reserved.
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published by
9 * the Free Software Foundation.
10 */
11#include <linux/err.h>
12#include <linux/module.h>
13#include <linux/list.h>
14#include <linux/clk.h>
15#include <linux/string.h>
16#include <linux/platform_device.h>
6310e472 17#include <linux/semaphore.h>
04c366f0 18
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19#include "clock.h"
20
21static LIST_HEAD(clocks);
22static DEFINE_SPINLOCK(clk_lock);
23
24struct clk *clk_get(struct device *dev, const char *id)
25{
26 struct clk *p, *ret = NULL, *retgen = NULL;
27 unsigned long flags;
28 int idno;
29
30 if (dev == NULL || dev->bus != &platform_bus_type)
31 idno = -1;
32 else
33 idno = to_platform_device(dev)->id;
34
35 spin_lock_irqsave(&clk_lock, flags);
36 list_for_each_entry(p, &clocks, node) {
37 if (strcmp(id, p->name) == 0) {
38 if (p->id == idno) {
39 if (!try_module_get(p->owner))
40 continue;
41 ret = p;
42 break;
43 } else if (p->id == -1)
44 /* remember match with id == -1 in case there is
45 * no clock for idno */
46 retgen = p;
47 }
48 }
49
50 if (!ret && retgen && try_module_get(retgen->owner))
51 ret = retgen;
52
53 if (ret)
54 ++ret->refcount;
55
56 spin_unlock_irqrestore(&clk_lock, flags);
57
58 return ret ? ret : ERR_PTR(-ENOENT);
59}
60EXPORT_SYMBOL(clk_get);
61
62void clk_put(struct clk *clk)
63{
64 module_put(clk->owner);
65 --clk->refcount;
66}
67EXPORT_SYMBOL(clk_put);
68
69static int clk_enable_unlocked(struct clk *clk)
70{
71 int ret = 0;
72 if (clk->parent) {
73 ret = clk_enable_unlocked(clk->parent);
74 if (ret)
75 return ret;
76 }
77
78 if (clk->usage++ == 0 && clk->endisable)
79 ret = clk->endisable(clk, 1);
80
81 return ret;
82}
83
84int clk_enable(struct clk *clk)
85{
86 int ret;
87 unsigned long flags;
88
89 spin_lock_irqsave(&clk_lock, flags);
90
91 ret = clk_enable_unlocked(clk);
92
93 spin_unlock_irqrestore(&clk_lock, flags);
94
95 return ret;
96}
97EXPORT_SYMBOL(clk_enable);
98
99static void clk_disable_unlocked(struct clk *clk)
100{
101 if (--clk->usage == 0 && clk->endisable)
102 clk->endisable(clk, 0);
103
104 if (clk->parent)
105 clk_disable_unlocked(clk->parent);
106}
107
108void clk_disable(struct clk *clk)
109{
110 unsigned long flags;
111
112 spin_lock_irqsave(&clk_lock, flags);
113
114 clk_disable_unlocked(clk);
115
116 spin_unlock_irqrestore(&clk_lock, flags);
117}
118EXPORT_SYMBOL(clk_disable);
119
120unsigned long clk_get_rate(struct clk *clk)
121{
122 if (clk->get_rate)
123 return clk->get_rate(clk);
124
125 if (clk->rate)
126 return clk->rate;
127
128 if (clk->parent)
129 return clk_get_rate(clk->parent);
130
131 return 0;
132}
133EXPORT_SYMBOL(clk_get_rate);
134
135int clk_register(struct clk *clk)
136{
137 unsigned long flags;
138
139 spin_lock_irqsave(&clk_lock, flags);
140
141 list_add(&clk->node, &clocks);
142
143 if (clk->parent)
144 ++clk->parent->refcount;
145
146 spin_unlock_irqrestore(&clk_lock, flags);
147
148 return 0;
149}
150
151int clk_unregister(struct clk *clk)
152{
153 int ret = 0;
154 unsigned long flags;
155
156 spin_lock_irqsave(&clk_lock, flags);
157
158 if (clk->usage || clk->refcount)
159 ret = -EBUSY;
160 else
161 list_del(&clk->node);
162
163 if (clk->parent)
164 --clk->parent->refcount;
165
166 spin_unlock_irqrestore(&clk_lock, flags);
167
168 return ret;
169}
170
171#if defined CONFIG_DEBUG_FS
172
173#include <linux/debugfs.h>
174#include <linux/seq_file.h>
175
176static int clk_debugfs_show(struct seq_file *s, void *null)
177{
178 unsigned long flags;
179 struct clk *p;
180
181 spin_lock_irqsave(&clk_lock, flags);
182
183 list_for_each_entry(p, &clocks, node)
184 seq_printf(s, "%s.%d: usage=%lu refcount=%lu rate=%lu\n",
185 p->name, p->id, p->usage, p->refcount,
186 p->usage ? clk_get_rate(p) : 0);
187
188 spin_unlock_irqrestore(&clk_lock, flags);
189
190 return 0;
191}
192
193static int clk_debugfs_open(struct inode *inode, struct file *file)
194{
195 return single_open(file, clk_debugfs_show, NULL);
196}
197
198static struct file_operations clk_debugfs_operations = {
199 .open = clk_debugfs_open,
200 .read = seq_read,
201 .llseek = seq_lseek,
202 .release = single_release,
203};
204
205static int __init clk_debugfs_init(void)
206{
207 struct dentry *dentry;
208
209 dentry = debugfs_create_file("clk", S_IFREG | S_IRUGO, NULL, NULL,
210 &clk_debugfs_operations);
211 return IS_ERR(dentry) ? PTR_ERR(dentry) : 0;
212}
213subsys_initcall(clk_debugfs_init);
214
215#endif /* if defined CONFIG_DEBUG_FS */
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