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 *clk_find(const char *dev_id, const char *con_id)
38 struct clk *clk = NULL;
41 list_for_each_entry(p, &clocks, node) {
44 if (!dev_id || strcmp(p->dev_id, dev_id))
49 if (!con_id || strcmp(p->con_id, con_id))
65 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
69 mutex_lock(&clocks_mutex);
70 clk = clk_find(dev_id, con_id);
71 if (clk && !__clk_get(clk))
73 mutex_unlock(&clocks_mutex);
75 return clk ? clk : ERR_PTR(-ENOENT);
77 EXPORT_SYMBOL(clk_get_sys);
79 struct clk *clk_get(struct device *dev, const char *con_id)
81 const char *dev_id = dev ? dev_name(dev) : NULL;
83 return clk_get_sys(dev_id, con_id);
85 EXPORT_SYMBOL(clk_get);
87 void clk_put(struct clk *clk)
91 EXPORT_SYMBOL(clk_put);
93 void clkdev_add(struct clk_lookup *cl)
95 mutex_lock(&clocks_mutex);
96 list_add_tail(&cl->node, &clocks);
97 mutex_unlock(&clocks_mutex);
99 EXPORT_SYMBOL(clkdev_add);
101 void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
103 mutex_lock(&clocks_mutex);
105 list_add_tail(&cl->node, &clocks);
108 mutex_unlock(&clocks_mutex);
111 #define MAX_DEV_ID 20
112 #define MAX_CON_ID 16
114 struct clk_lookup_alloc {
115 struct clk_lookup cl;
116 char dev_id[MAX_DEV_ID];
117 char con_id[MAX_CON_ID];
120 struct clk_lookup * __init_refok
121 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
123 struct clk_lookup_alloc *cla;
125 cla = __clkdev_alloc(sizeof(*cla));
131 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
132 cla->cl.con_id = cla->con_id;
138 va_start(ap, dev_fmt);
139 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
140 cla->cl.dev_id = cla->dev_id;
146 EXPORT_SYMBOL(clkdev_alloc);
148 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
151 struct clk *r = clk_get(dev, id);
152 struct clk_lookup *l;
157 l = clkdev_alloc(r, alias, alias_dev_name);
164 EXPORT_SYMBOL(clk_add_alias);
167 * clkdev_drop - remove a clock dynamically allocated
169 void clkdev_drop(struct clk_lookup *cl)
171 mutex_lock(&clocks_mutex);
173 mutex_unlock(&clocks_mutex);
176 EXPORT_SYMBOL(clkdev_drop);