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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 | |
26 | static LIST_HEAD(clocks); |
27 | static 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 | */ |
38 | static 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 | |
57 | if (match > best) { |
58 | clk = p->clk; |
59 | if (match != 3) |
60 | best = match; |
61 | else |
62 | break; |
63 | } |
64 | } |
65 | return clk; |
66 | } |
67 | |
68 | struct clk *clk_get_sys(const char *dev_id, const char *con_id) |
69 | { |
70 | struct clk *clk; |
71 | |
72 | mutex_lock(&clocks_mutex); |
73 | clk = clk_find(dev_id, con_id); |
74 | if (clk && !__clk_get(clk)) |
75 | clk = NULL; |
76 | mutex_unlock(&clocks_mutex); |
77 | |
78 | return clk ? clk : ERR_PTR(-ENOENT); |
79 | } |
80 | EXPORT_SYMBOL(clk_get_sys); |
81 | |
82 | struct clk *clk_get(struct device *dev, const char *con_id) |
83 | { |
84 | const char *dev_id = dev ? dev_name(dev) : NULL; |
85 | |
86 | return clk_get_sys(dev_id, con_id); |
87 | } |
88 | EXPORT_SYMBOL(clk_get); |
89 | |
90 | void clk_put(struct clk *clk) |
91 | { |
92 | __clk_put(clk); |
93 | } |
94 | EXPORT_SYMBOL(clk_put); |
95 | |
96 | void clkdev_add(struct clk_lookup *cl) |
97 | { |
98 | mutex_lock(&clocks_mutex); |
99 | list_add_tail(&cl->node, &clocks); |
100 | mutex_unlock(&clocks_mutex); |
101 | } |
102 | EXPORT_SYMBOL(clkdev_add); |
103 | |
104 | void __init clkdev_add_table(struct clk_lookup *cl, size_t num) |
105 | { |
106 | mutex_lock(&clocks_mutex); |
107 | while (num--) { |
108 | list_add_tail(&cl->node, &clocks); |
109 | cl++; |
110 | } |
111 | mutex_unlock(&clocks_mutex); |
112 | } |
113 | |
114 | #define MAX_DEV_ID 20 |
115 | #define MAX_CON_ID 16 |
116 | |
117 | struct clk_lookup_alloc { |
118 | struct clk_lookup cl; |
119 | char dev_id[MAX_DEV_ID]; |
120 | char con_id[MAX_CON_ID]; |
121 | }; |
122 | |
123 | struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id, |
124 | const char *dev_fmt, ...) |
125 | { |
126 | struct clk_lookup_alloc *cla; |
127 | |
128 | cla = kzalloc(sizeof(*cla), GFP_KERNEL); |
129 | if (!cla) |
130 | return NULL; |
131 | |
132 | cla->cl.clk = clk; |
133 | if (con_id) { |
134 | strlcpy(cla->con_id, con_id, sizeof(cla->con_id)); |
135 | cla->cl.con_id = cla->con_id; |
136 | } |
137 | |
138 | if (dev_fmt) { |
139 | va_list ap; |
140 | |
141 | va_start(ap, dev_fmt); |
142 | vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap); |
143 | cla->cl.dev_id = cla->dev_id; |
144 | va_end(ap); |
145 | } |
146 | |
147 | return &cla->cl; |
148 | } |
149 | EXPORT_SYMBOL(clkdev_alloc); |
150 | |
151 | int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, |
152 | struct device *dev) |
153 | { |
154 | struct clk *r = clk_get(dev, id); |
155 | struct clk_lookup *l; |
156 | |
157 | if (IS_ERR(r)) |
158 | return PTR_ERR(r); |
159 | |
160 | l = clkdev_alloc(r, alias, alias_dev_name); |
161 | clk_put(r); |
162 | if (!l) |
163 | return -ENODEV; |
164 | clkdev_add(l); |
165 | return 0; |
166 | } |
167 | EXPORT_SYMBOL(clk_add_alias); |
168 | |
169 | /* |
170 | * clkdev_drop - remove a clock dynamically allocated |
171 | */ |
172 | void clkdev_drop(struct clk_lookup *cl) |
173 | { |
174 | mutex_lock(&clocks_mutex); |
175 | list_del(&cl->node); |
176 | mutex_unlock(&clocks_mutex); |
177 | kfree(cl); |
178 | } |
179 | EXPORT_SYMBOL(clkdev_drop); |
180 |
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