Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * arch/arm/common/clkdev.c
3 *
4 * Copyright (C) 2008 Russell King.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Helper for the clk API to assist looking up a struct clk.
11 */
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/device.h>
15#include <linux/list.h>
16#include <linux/errno.h>
17#include <linux/err.h>
18#include <linux/string.h>
19#include <linux/mutex.h>
20#include <linux/clk.h>
21#include <linux/slab.h>
22
23#include <asm/clkdev.h>
24#include <mach/clkdev.h>
25
26static LIST_HEAD(clocks);
27static DEFINE_MUTEX(clocks_mutex);
28
29/*
30 * Find the correct struct clk for the device and connection ID.
31 * We do slightly fuzzy matching here:
32 * An entry with a NULL ID is assumed to be a wildcard.
33 * If an entry has a device ID, it must match
34 * If an entry has a connection ID, it must match
35 * Then we take the most specific entry - with the following
36 * order of precedence: dev+con > dev only > con only.
37 */
38static struct clk *clk_find(const char *dev_id, const char *con_id)
39{
40 struct clk_lookup *p;
41 struct clk *clk = NULL;
42 int match, best = 0;
43
44 list_for_each_entry(p, &clocks, node) {
45 match = 0;
46 if (p->dev_id) {
47 if (!dev_id || strcmp(p->dev_id, dev_id))
48 continue;
49 match += 2;
50 }
51 if (p->con_id) {
52 if (!con_id || strcmp(p->con_id, con_id))
53 continue;
54 match += 1;
55 }
56 if (match == 0)
57 continue;
58
59 if (match > best) {
60 clk = p->clk;
61 best = match;
62 }
63 }
64 return clk;
65}
66
67struct clk *clk_get_sys(const char *dev_id, const char *con_id)
68{
69 struct clk *clk;
70
71 mutex_lock(&clocks_mutex);
72 clk = clk_find(dev_id, con_id);
73 if (clk && !__clk_get(clk))
74 clk = NULL;
75 mutex_unlock(&clocks_mutex);
76
77 return clk ? clk : ERR_PTR(-ENOENT);
78}
79EXPORT_SYMBOL(clk_get_sys);
80
81struct clk *clk_get(struct device *dev, const char *con_id)
82{
83 const char *dev_id = dev ? dev_name(dev) : NULL;
84
85 return clk_get_sys(dev_id, con_id);
86}
87EXPORT_SYMBOL(clk_get);
88
89void clk_put(struct clk *clk)
90{
91 __clk_put(clk);
92}
93EXPORT_SYMBOL(clk_put);
94
95void clkdev_add(struct clk_lookup *cl)
96{
97 mutex_lock(&clocks_mutex);
98 list_add_tail(&cl->node, &clocks);
99 mutex_unlock(&clocks_mutex);
100}
101EXPORT_SYMBOL(clkdev_add);
102
103void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
104{
105 mutex_lock(&clocks_mutex);
106 while (num--) {
107 list_add_tail(&cl->node, &clocks);
108 cl++;
109 }
110 mutex_unlock(&clocks_mutex);
111}
112
113#define MAX_DEV_ID 20
114#define MAX_CON_ID 16
115
116struct clk_lookup_alloc {
117 struct clk_lookup cl;
118 char dev_id[MAX_DEV_ID];
119 char con_id[MAX_CON_ID];
120};
121
122struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id,
123 const char *dev_fmt, ...)
124{
125 struct clk_lookup_alloc *cla;
126
127 cla = kzalloc(sizeof(*cla), GFP_KERNEL);
128 if (!cla)
129 return NULL;
130
131 cla->cl.clk = clk;
132 if (con_id) {
133 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
134 cla->cl.con_id = cla->con_id;
135 }
136
137 if (dev_fmt) {
138 va_list ap;
139
140 va_start(ap, dev_fmt);
141 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
142 cla->cl.dev_id = cla->dev_id;
143 va_end(ap);
144 }
145
146 return &cla->cl;
147}
148EXPORT_SYMBOL(clkdev_alloc);
149
150int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
151 struct device *dev)
152{
153 struct clk *r = clk_get(dev, id);
154 struct clk_lookup *l;
155
156 if (IS_ERR(r))
157 return PTR_ERR(r);
158
159 l = clkdev_alloc(r, alias, alias_dev_name);
160 clk_put(r);
161 if (!l)
162 return -ENODEV;
163 clkdev_add(l);
164 return 0;
165}
166EXPORT_SYMBOL(clk_add_alias);
167
168/*
169 * clkdev_drop - remove a clock dynamically allocated
170 */
171void clkdev_drop(struct clk_lookup *cl)
172{
173 mutex_lock(&clocks_mutex);
174 list_del(&cl->node);
175 mutex_unlock(&clocks_mutex);
176 kfree(cl);
177}
178EXPORT_SYMBOL(clkdev_drop);