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>
26 static LIST_HEAD(clocks);
27 static DEFINE_MUTEX(clocks_mutex);
29 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
30 struct clk *of_clk_get(struct device_node *np, int index)
32 struct of_phandle_args clkspec;
37 return ERR_PTR(-EINVAL);
39 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
45 clk = __of_clk_get_from_provider(&clkspec);
47 if (!IS_ERR(clk) && !__clk_get(clk))
48 clk = ERR_PTR(-ENOENT);
51 of_node_put(clkspec.np);
54 EXPORT_SYMBOL(of_clk_get);
57 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
58 * @np: pointer to clock consumer node
59 * @name: name of consumer's clock input, or NULL for the first clock reference
61 * This function parses the clocks and clock-names properties,
62 * and uses them to look up the struct clk from the registered list of clock
65 struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
67 struct clk *clk = ERR_PTR(-ENOENT);
69 /* Walk up the tree of devices looking for a clock that matches */
74 * For named clocks, first look up the name in the
75 * "clock-names" property. If it cannot be found, then
76 * index will be an error code, and of_clk_get() will fail.
79 index = of_property_match_string(np, "clock-names", name);
80 clk = of_clk_get(np, index);
83 else if (name && index >= 0) {
84 pr_err("ERROR: could not get clock %s:%s(%i)\n",
85 np->full_name, name ? name : "", index);
90 * No matching clock found on this node. If the parent node
91 * has a "clock-ranges" property, then we can try one of its
95 if (np && !of_get_property(np, "clock-ranges", NULL))
101 EXPORT_SYMBOL(of_clk_get_by_name);
105 * Find the correct struct clk for the device and connection ID.
106 * We do slightly fuzzy matching here:
107 * An entry with a NULL ID is assumed to be a wildcard.
108 * If an entry has a device ID, it must match
109 * If an entry has a connection ID, it must match
110 * Then we take the most specific entry - with the following
111 * order of precedence: dev+con > dev only > con only.
113 static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
115 struct clk_lookup *p, *cl = NULL;
116 int match, best_found = 0, best_possible = 0;
123 list_for_each_entry(p, &clocks, node) {
126 if (!dev_id || strcmp(p->dev_id, dev_id))
131 if (!con_id || strcmp(p->con_id, con_id))
136 if (match > best_found) {
138 if (match != best_possible)
147 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
149 struct clk_lookup *cl;
151 mutex_lock(&clocks_mutex);
152 cl = clk_find(dev_id, con_id);
153 if (cl && !__clk_get(cl->clk))
155 mutex_unlock(&clocks_mutex);
157 return cl ? cl->clk : ERR_PTR(-ENOENT);
159 EXPORT_SYMBOL(clk_get_sys);
161 struct clk *clk_get(struct device *dev, const char *con_id)
163 const char *dev_id = dev ? dev_name(dev) : NULL;
167 clk = of_clk_get_by_name(dev->of_node, con_id);
170 if (PTR_ERR(clk) == -EPROBE_DEFER)
174 return clk_get_sys(dev_id, con_id);
176 EXPORT_SYMBOL(clk_get);
178 void clk_put(struct clk *clk)
182 EXPORT_SYMBOL(clk_put);
184 void clkdev_add(struct clk_lookup *cl)
186 mutex_lock(&clocks_mutex);
187 list_add_tail(&cl->node, &clocks);
188 mutex_unlock(&clocks_mutex);
190 EXPORT_SYMBOL(clkdev_add);
192 void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
194 mutex_lock(&clocks_mutex);
196 list_add_tail(&cl->node, &clocks);
199 mutex_unlock(&clocks_mutex);
202 #define MAX_DEV_ID 20
203 #define MAX_CON_ID 16
205 struct clk_lookup_alloc {
206 struct clk_lookup cl;
207 char dev_id[MAX_DEV_ID];
208 char con_id[MAX_CON_ID];
211 static struct clk_lookup * __init_refok
212 vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt,
215 struct clk_lookup_alloc *cla;
217 cla = __clkdev_alloc(sizeof(*cla));
223 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
224 cla->cl.con_id = cla->con_id;
228 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
229 cla->cl.dev_id = cla->dev_id;
235 struct clk_lookup * __init_refok
236 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
238 struct clk_lookup *cl;
241 va_start(ap, dev_fmt);
242 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
247 EXPORT_SYMBOL(clkdev_alloc);
249 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
252 struct clk *r = clk_get(dev, id);
253 struct clk_lookup *l;
258 l = clkdev_alloc(r, alias, alias_dev_name);
265 EXPORT_SYMBOL(clk_add_alias);
268 * clkdev_drop - remove a clock dynamically allocated
270 void clkdev_drop(struct clk_lookup *cl)
272 mutex_lock(&clocks_mutex);
274 mutex_unlock(&clocks_mutex);
277 EXPORT_SYMBOL(clkdev_drop);
280 * clk_register_clkdev - register one clock lookup for a struct clk
281 * @clk: struct clk to associate with all clk_lookups
282 * @con_id: connection ID string on device
283 * @dev_id: format string describing device name
285 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
288 * To make things easier for mass registration, we detect error clks
289 * from a previous clk_register() call, and return the error code for
290 * those. This is to permit this function to be called immediately
291 * after clk_register().
293 int clk_register_clkdev(struct clk *clk, const char *con_id,
294 const char *dev_fmt, ...)
296 struct clk_lookup *cl;
302 va_start(ap, dev_fmt);
303 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
315 * clk_register_clkdevs - register a set of clk_lookup for a struct clk
316 * @clk: struct clk to associate with all clk_lookups
317 * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized
318 * @num: number of clk_lookup structures to register
320 * To make things easier for mass registration, we detect error clks
321 * from a previous clk_register() call, and return the error code for
322 * those. This is to permit this function to be called immediately
323 * after clk_register().
325 int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num)
332 for (i = 0; i < num; i++, cl++) {
339 EXPORT_SYMBOL(clk_register_clkdevs);