2 * arch/arm/common/clkdev.c
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>
22 #include <asm/clkdev.h>
23 #include <mach/clkdev.h>
25 static LIST_HEAD(clocks);
26 static DEFINE_MUTEX(clocks_mutex);
29 * Find the correct struct clk for the device and connection ID.
30 * We do slightly fuzzy matching here:
31 * An entry with a NULL ID is assumed to be a wildcard.
32 * If an entry has a device ID, it must match
33 * If an entry has a connection ID, it must match
34 * Then we take the most specific entry - with the following
35 * order of precedence: dev+con > dev only > con only.
37 static struct clk *clk_find(const char *dev_id, const char *con_id)
40 struct clk *clk = NULL;
43 list_for_each_entry(p, &clocks, node) {
46 if (!dev_id || strcmp(p->dev_id, dev_id))
51 if (!con_id || strcmp(p->con_id, con_id))
66 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
70 mutex_lock(&clocks_mutex);
71 clk = clk_find(dev_id, con_id);
72 if (clk && !__clk_get(clk))
74 mutex_unlock(&clocks_mutex);
76 return clk ? clk : ERR_PTR(-ENOENT);
78 EXPORT_SYMBOL(clk_get_sys);
80 struct clk *clk_get(struct device *dev, const char *con_id)
82 const char *dev_id = dev ? dev_name(dev) : NULL;
84 return clk_get_sys(dev_id, con_id);
86 EXPORT_SYMBOL(clk_get);
88 void clk_put(struct clk *clk)
92 EXPORT_SYMBOL(clk_put);
94 void clkdev_add(struct clk_lookup *cl)
96 mutex_lock(&clocks_mutex);
97 list_add_tail(&cl->node, &clocks);
98 mutex_unlock(&clocks_mutex);
100 EXPORT_SYMBOL(clkdev_add);
102 void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
104 mutex_lock(&clocks_mutex);
106 list_add_tail(&cl->node, &clocks);
109 mutex_unlock(&clocks_mutex);
112 #define MAX_DEV_ID 20
113 #define MAX_CON_ID 16
115 struct clk_lookup_alloc {
116 struct clk_lookup cl;
117 char dev_id[MAX_DEV_ID];
118 char con_id[MAX_CON_ID];
121 struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id,
122 const char *dev_fmt, ...)
124 struct clk_lookup_alloc *cla;
126 cla = kzalloc(sizeof(*cla), GFP_KERNEL);
132 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
133 cla->cl.con_id = cla->con_id;
139 va_start(ap, dev_fmt);
140 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
141 cla->cl.dev_id = cla->dev_id;
147 EXPORT_SYMBOL(clkdev_alloc);
149 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
152 struct clk *r = clk_get(dev, id);
153 struct clk_lookup *l;
158 l = clkdev_alloc(r, alias, alias_dev_name);
165 EXPORT_SYMBOL(clk_add_alias);
168 * clkdev_drop - remove a clock dynamically allocated
170 void clkdev_drop(struct clk_lookup *cl)
172 mutex_lock(&clocks_mutex);
174 mutex_unlock(&clocks_mutex);
177 EXPORT_SYMBOL(clkdev_drop);