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0318e693 RK |
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 | ||
21 | #include <asm/clkdev.h> | |
22 | #include <mach/clkdev.h> | |
23 | ||
24 | static LIST_HEAD(clocks); | |
25 | static DEFINE_MUTEX(clocks_mutex); | |
26 | ||
409dc360 RK |
27 | /* |
28 | * Find the correct struct clk for the device and connection ID. | |
29 | * We do slightly fuzzy matching here: | |
30 | * An entry with a NULL ID is assumed to be a wildcard. | |
31 | * If an entry has a device ID, it must match | |
32 | * If an entry has a connection ID, it must match | |
33 | * Then we take the most specific entry - with the following | |
34 | * order of precidence: dev+con > dev only > con only. | |
35 | */ | |
0318e693 RK |
36 | static struct clk *clk_find(const char *dev_id, const char *con_id) |
37 | { | |
38 | struct clk_lookup *p; | |
39 | struct clk *clk = NULL; | |
40 | int match, best = 0; | |
41 | ||
42 | list_for_each_entry(p, &clocks, node) { | |
0318e693 | 43 | match = 0; |
409dc360 RK |
44 | if (p->dev_id) { |
45 | if (!dev_id || strcmp(p->dev_id, dev_id)) | |
46 | continue; | |
47 | match += 2; | |
48 | } | |
49 | if (p->con_id) { | |
50 | if (!con_id || strcmp(p->con_id, con_id)) | |
51 | continue; | |
52 | match += 1; | |
53 | } | |
0318e693 RK |
54 | if (match == 0) |
55 | continue; | |
56 | ||
57 | if (match > best) { | |
58 | clk = p->clk; | |
59 | best = match; | |
60 | } | |
61 | } | |
62 | return clk; | |
63 | } | |
64 | ||
65 | struct clk *clk_get(struct device *dev, const char *con_id) | |
66 | { | |
67 | const char *dev_id = dev ? dev_name(dev) : NULL; | |
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); | |
79 | ||
80 | void clk_put(struct clk *clk) | |
81 | { | |
82 | __clk_put(clk); | |
83 | } | |
84 | EXPORT_SYMBOL(clk_put); | |
85 | ||
86 | void clkdev_add(struct clk_lookup *cl) | |
87 | { | |
88 | mutex_lock(&clocks_mutex); | |
89 | list_add_tail(&cl->node, &clocks); | |
90 | mutex_unlock(&clocks_mutex); | |
91 | } | |
92 | EXPORT_SYMBOL(clkdev_add); | |
93 | ||
94 | #define MAX_DEV_ID 20 | |
95 | #define MAX_CON_ID 16 | |
96 | ||
97 | struct clk_lookup_alloc { | |
98 | struct clk_lookup cl; | |
99 | char dev_id[MAX_DEV_ID]; | |
100 | char con_id[MAX_CON_ID]; | |
101 | }; | |
102 | ||
103 | struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id, | |
104 | const char *dev_fmt, ...) | |
105 | { | |
106 | struct clk_lookup_alloc *cla; | |
107 | ||
108 | cla = kzalloc(sizeof(*cla), GFP_KERNEL); | |
109 | if (!cla) | |
110 | return NULL; | |
111 | ||
112 | cla->cl.clk = clk; | |
113 | if (con_id) { | |
114 | strlcpy(cla->con_id, con_id, sizeof(cla->con_id)); | |
115 | cla->cl.con_id = cla->con_id; | |
116 | } | |
117 | ||
118 | if (dev_fmt) { | |
119 | va_list ap; | |
120 | ||
121 | va_start(ap, dev_fmt); | |
122 | vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap); | |
123 | cla->cl.dev_id = cla->dev_id; | |
124 | va_end(ap); | |
125 | } | |
126 | ||
127 | return &cla->cl; | |
128 | } | |
129 | EXPORT_SYMBOL(clkdev_alloc); | |
130 | ||
131 | /* | |
132 | * clkdev_drop - remove a clock dynamically allocated | |
133 | */ | |
134 | void clkdev_drop(struct clk_lookup *cl) | |
135 | { | |
136 | mutex_lock(&clocks_mutex); | |
137 | list_del(&cl->node); | |
138 | mutex_unlock(&clocks_mutex); | |
139 | kfree(cl); | |
140 | } | |
141 | EXPORT_SYMBOL(clkdev_drop); |