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;
38 int match, best_found = 0, best_possible = 0;
45 list_for_each_entry(p, &clocks, node) {
48 if (!dev_id || strcmp(p->dev_id, dev_id))
53 if (!con_id || strcmp(p->con_id, con_id))
58 if (match > best_found) {
60 if (match != best_possible)
69 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
71 struct clk_lookup *cl;
73 mutex_lock(&clocks_mutex);
74 cl = clk_find(dev_id, con_id);
75 if (cl && !__clk_get(cl->clk))
77 mutex_unlock(&clocks_mutex);
79 return cl ? cl->clk : ERR_PTR(-ENOENT);
81 EXPORT_SYMBOL(clk_get_sys);
83 struct clk *clk_get(struct device *dev, const char *con_id)
85 const char *dev_id = dev ? dev_name(dev) : NULL;
87 return clk_get_sys(dev_id, con_id);
89 EXPORT_SYMBOL(clk_get);
91 void clk_put(struct clk *clk)
95 EXPORT_SYMBOL(clk_put);
97 static void devm_clk_release(struct device *dev, void *res)
99 clk_put(*(struct clk **)res);
102 struct clk *devm_clk_get(struct device *dev, const char *id)
104 struct clk **ptr, *clk;
106 ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
108 return ERR_PTR(-ENOMEM);
110 clk = clk_get(dev, id);
113 devres_add(dev, ptr);
120 EXPORT_SYMBOL(devm_clk_get);
122 static int devm_clk_match(struct device *dev, void *res, void *data)
124 struct clk **c = res;
132 void devm_clk_put(struct device *dev, struct clk *clk)
136 ret = devres_destroy(dev, devm_clk_release, devm_clk_match, clk);
140 EXPORT_SYMBOL(devm_clk_put);
142 void clkdev_add(struct clk_lookup *cl)
144 mutex_lock(&clocks_mutex);
145 list_add_tail(&cl->node, &clocks);
146 mutex_unlock(&clocks_mutex);
148 EXPORT_SYMBOL(clkdev_add);
150 void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
152 mutex_lock(&clocks_mutex);
154 list_add_tail(&cl->node, &clocks);
157 mutex_unlock(&clocks_mutex);
160 #define MAX_DEV_ID 20
161 #define MAX_CON_ID 16
163 struct clk_lookup_alloc {
164 struct clk_lookup cl;
165 char dev_id[MAX_DEV_ID];
166 char con_id[MAX_CON_ID];
169 static struct clk_lookup * __init_refok
170 vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt,
173 struct clk_lookup_alloc *cla;
175 cla = __clkdev_alloc(sizeof(*cla));
181 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
182 cla->cl.con_id = cla->con_id;
186 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
187 cla->cl.dev_id = cla->dev_id;
193 struct clk_lookup * __init_refok
194 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
196 struct clk_lookup *cl;
199 va_start(ap, dev_fmt);
200 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
205 EXPORT_SYMBOL(clkdev_alloc);
207 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
210 struct clk *r = clk_get(dev, id);
211 struct clk_lookup *l;
216 l = clkdev_alloc(r, alias, alias_dev_name);
223 EXPORT_SYMBOL(clk_add_alias);
226 * clkdev_drop - remove a clock dynamically allocated
228 void clkdev_drop(struct clk_lookup *cl)
230 mutex_lock(&clocks_mutex);
232 mutex_unlock(&clocks_mutex);
235 EXPORT_SYMBOL(clkdev_drop);
238 * clk_register_clkdev - register one clock lookup for a struct clk
239 * @clk: struct clk to associate with all clk_lookups
240 * @con_id: connection ID string on device
241 * @dev_id: format string describing device name
243 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
246 * To make things easier for mass registration, we detect error clks
247 * from a previous clk_register() call, and return the error code for
248 * those. This is to permit this function to be called immediately
249 * after clk_register().
251 int clk_register_clkdev(struct clk *clk, const char *con_id,
252 const char *dev_fmt, ...)
254 struct clk_lookup *cl;
260 va_start(ap, dev_fmt);
261 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
273 * clk_register_clkdevs - register a set of clk_lookup for a struct clk
274 * @clk: struct clk to associate with all clk_lookups
275 * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized
276 * @num: number of clk_lookup structures to register
278 * To make things easier for mass registration, we detect error clks
279 * from a previous clk_register() call, and return the error code for
280 * those. This is to permit this function to be called immediately
281 * after clk_register().
283 int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num)
290 for (i = 0; i < num; i++, cl++) {
297 EXPORT_SYMBOL(clk_register_clkdevs);