4 * Copyright (C) 2008 Russell King.
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.
10 * Helper for the clk API to assist looking up a struct clk.
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/clkdev.h>
23 static LIST_HEAD(clocks);
24 static DEFINE_MUTEX(clocks_mutex);
27 * Find the correct struct clk for the device and connection ID.
28 * We do slightly fuzzy matching here:
29 * An entry with a NULL ID is assumed to be a wildcard.
30 * If an entry has a device ID, it must match
31 * If an entry has a connection ID, it must match
32 * Then we take the most specific entry - with the following
33 * order of precedence: dev+con > dev only > con only.
35 static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
37 struct clk_lookup *p, *cl = NULL;
40 list_for_each_entry(p, &clocks, node) {
43 if (!dev_id || strcmp(p->dev_id, dev_id))
48 if (!con_id || strcmp(p->con_id, con_id))
64 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
66 struct clk_lookup *cl;
68 mutex_lock(&clocks_mutex);
69 cl = clk_find(dev_id, con_id);
70 if (cl && !__clk_get(cl->clk))
72 mutex_unlock(&clocks_mutex);
74 return cl ? cl->clk : ERR_PTR(-ENOENT);
76 EXPORT_SYMBOL(clk_get_sys);
78 struct clk *clk_get(struct device *dev, const char *con_id)
80 const char *dev_id = dev ? dev_name(dev) : NULL;
82 return clk_get_sys(dev_id, con_id);
84 EXPORT_SYMBOL(clk_get);
86 void clk_put(struct clk *clk)
90 EXPORT_SYMBOL(clk_put);
92 void clkdev_add(struct clk_lookup *cl)
94 mutex_lock(&clocks_mutex);
95 list_add_tail(&cl->node, &clocks);
96 mutex_unlock(&clocks_mutex);
98 EXPORT_SYMBOL(clkdev_add);
100 void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
102 mutex_lock(&clocks_mutex);
104 list_add_tail(&cl->node, &clocks);
107 mutex_unlock(&clocks_mutex);
110 #define MAX_DEV_ID 20
111 #define MAX_CON_ID 16
113 struct clk_lookup_alloc {
114 struct clk_lookup cl;
115 char dev_id[MAX_DEV_ID];
116 char con_id[MAX_CON_ID];
119 struct clk_lookup * __init_refok
120 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
122 struct clk_lookup_alloc *cla;
124 cla = __clkdev_alloc(sizeof(*cla));
130 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
131 cla->cl.con_id = cla->con_id;
137 va_start(ap, dev_fmt);
138 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
139 cla->cl.dev_id = cla->dev_id;
145 EXPORT_SYMBOL(clkdev_alloc);
147 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
150 struct clk *r = clk_get(dev, id);
151 struct clk_lookup *l;
156 l = clkdev_alloc(r, alias, alias_dev_name);
163 EXPORT_SYMBOL(clk_add_alias);
166 * clkdev_drop - remove a clock dynamically allocated
168 void clkdev_drop(struct clk_lookup *cl)
170 mutex_lock(&clocks_mutex);
172 mutex_unlock(&clocks_mutex);
175 EXPORT_SYMBOL(clkdev_drop);