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
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 */
clk_find(const char * dev_id,const char * con_id)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) {
43 match = 0;
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 }
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
clk_get(struct device * dev,const char * con_id)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
clk_put(struct clk * clk)80 void clk_put(struct clk *clk)
81 {
82 __clk_put(clk);
83 }
84 EXPORT_SYMBOL(clk_put);
85
clkdev_add(struct clk_lookup * cl)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
clkdev_alloc(struct clk * clk,const char * con_id,const char * dev_fmt,...)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 */
clkdev_drop(struct clk_lookup * cl)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);
142