Merge commit 'v2.6.27-rc3' into x86/urgent
[linux-2.6] / arch / arm / mach-ns9xxx / clock.c
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>
17 #include <linux/semaphore.h>
18
19 #include "clock.h"
20
21 static LIST_HEAD(clocks);
22 static DEFINE_SPINLOCK(clk_lock);
23
24 struct 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 }
60 EXPORT_SYMBOL(clk_get);
61
62 void clk_put(struct clk *clk)
63 {
64         module_put(clk->owner);
65         --clk->refcount;
66 }
67 EXPORT_SYMBOL(clk_put);
68
69 static 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
84 int 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 }
97 EXPORT_SYMBOL(clk_enable);
98
99 static 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
108 void 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 }
118 EXPORT_SYMBOL(clk_disable);
119
120 unsigned 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 }
133 EXPORT_SYMBOL(clk_get_rate);
134
135 int 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
151 int 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
176 static 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
193 static int clk_debugfs_open(struct inode *inode, struct file *file)
194 {
195         return single_open(file, clk_debugfs_show, NULL);
196 }
197
198 static 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
205 static 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 }
213 subsys_initcall(clk_debugfs_init);
214
215 #endif /* if defined CONFIG_DEBUG_FS */