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
22 #include <asm/clkdev.h>
23 #include <mach/clkdev.h>
24
25 static LIST_HEAD(clocks);
26 static DEFINE_MUTEX(clocks_mutex);
27
28 /*
29 * Find the correct struct clk for the device and connection ID.
30 * We do slightly fuzzy matching here:
31 * An entry with a NULL ID is assumed to be a wildcard.
32 * If an entry has a device ID, it must match
33 * If an entry has a connection ID, it must match
34 * Then we take the most specific entry - with the following
35 * order of precidence: dev+con > dev only > con only.
36 */
37 static struct clk *clk_find(const char *dev_id, const char *con_id)
38 {
39 struct clk_lookup *p;
40 struct clk *clk = NULL;
41 int match, best = 0;
42
43 list_for_each_entry(p, &clocks, node) {
44 match = 0;
45 if (p->dev_id) {
46 if (!dev_id || strcmp(p->dev_id, dev_id))
47 continue;
48 match += 2;
49 }
50 if (p->con_id) {
51 if (!con_id || strcmp(p->con_id, con_id))
52 continue;
53 match += 1;
54 }
55 if (match == 0)
56 continue;
57
58 if (match > best) {
59 clk = p->clk;
60 best = match;
61 }
62 }
63 return clk;
64 }
65
66 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
67 {
68 struct clk *clk;
69
70 mutex_lock(&clocks_mutex);
71 clk = clk_find(dev_id, con_id);
72 if (clk && !__clk_get(clk))
73 clk = NULL;
74 mutex_unlock(&clocks_mutex);
75
76 return clk ? clk : ERR_PTR(-ENOENT);
77 }
78 EXPORT_SYMBOL(clk_get_sys);
79
80 struct clk *clk_get(struct device *dev, const char *con_id)
81 {
82 const char *dev_id = dev ? dev_name(dev) : NULL;
83
84 return clk_get_sys(dev_id, con_id);
85 }
86 EXPORT_SYMBOL(clk_get);
87
88 void clk_put(struct clk *clk)
89 {
90 __clk_put(clk);
91 }
92 EXPORT_SYMBOL(clk_put);
93
94 void clkdev_add(struct clk_lookup *cl)
95 {
96 mutex_lock(&clocks_mutex);
97 list_add_tail(&cl->node, &clocks);
98 mutex_unlock(&clocks_mutex);
99 }
100 EXPORT_SYMBOL(clkdev_add);
101
102 #define MAX_DEV_ID 20
103 #define MAX_CON_ID 16
104
105 struct clk_lookup_alloc {
106 struct clk_lookup cl;
107 char dev_id[MAX_DEV_ID];
108 char con_id[MAX_CON_ID];
109 };
110
111 struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id,
112 const char *dev_fmt, ...)
113 {
114 struct clk_lookup_alloc *cla;
115
116 cla = kzalloc(sizeof(*cla), GFP_KERNEL);
117 if (!cla)
118 return NULL;
119
120 cla->cl.clk = clk;
121 if (con_id) {
122 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
123 cla->cl.con_id = cla->con_id;
124 }
125
126 if (dev_fmt) {
127 va_list ap;
128
129 va_start(ap, dev_fmt);
130 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
131 cla->cl.dev_id = cla->dev_id;
132 va_end(ap);
133 }
134
135 return &cla->cl;
136 }
137 EXPORT_SYMBOL(clkdev_alloc);
138
139 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
140 struct device *dev)
141 {
142 struct clk *r = clk_get(dev, id);
143 struct clk_lookup *l;
144
145 if (IS_ERR(r))
146 return PTR_ERR(r);
147
148 l = clkdev_alloc(r, alias, alias_dev_name);
149 clk_put(r);
150 if (!l)
151 return -ENODEV;
152 clkdev_add(l);
153 return 0;
154 }
155 EXPORT_SYMBOL(clk_add_alias);
156
157 /*
158 * clkdev_drop - remove a clock dynamically allocated
159 */
160 void clkdev_drop(struct clk_lookup *cl)
161 {
162 mutex_lock(&clocks_mutex);
163 list_del(&cl->node);
164 mutex_unlock(&clocks_mutex);
165 kfree(cl);
166 }
167 EXPORT_SYMBOL(clkdev_drop);
168
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