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)
32 * of_clk_get_by_clkspec() - Lookup a clock form a clock provider
33 * @clkspec: pointer to a clock specifier data structure
35 * This function looks up a struct clk from the registered list of clock
36 * providers, an input is a clock specifier data structure as returned
37 * from the of_parse_phandle_with_args() function call.
39 struct clk *of_clk_get_by_clkspec(struct of_phandle_args *clkspec)
44 return ERR_PTR(-EINVAL);
47 clk = __of_clk_get_from_provider(clkspec);
49 if (!IS_ERR(clk) && !__clk_get(clk))
50 clk = ERR_PTR(-ENOENT);
56 struct clk *of_clk_get(struct device_node *np, int index)
58 struct of_phandle_args clkspec;
63 return ERR_PTR(-EINVAL);
65 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
70 clk = of_clk_get_by_clkspec(&clkspec);
71 of_node_put(clkspec.np);
74 EXPORT_SYMBOL(of_clk_get);
77 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
78 * @np: pointer to clock consumer node
79 * @name: name of consumer's clock input, or NULL for the first clock reference
81 * This function parses the clocks and clock-names properties,
82 * and uses them to look up the struct clk from the registered list of clock
85 struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
87 struct clk *clk = ERR_PTR(-ENOENT);
89 /* Walk up the tree of devices looking for a clock that matches */
94 * For named clocks, first look up the name in the
95 * "clock-names" property. If it cannot be found, then
96 * index will be an error code, and of_clk_get() will fail.
99 index = of_property_match_string(np, "clock-names", name);
100 clk = of_clk_get(np, index);
103 else if (name && index >= 0) {
104 if (PTR_ERR(clk) != -EPROBE_DEFER)
105 pr_err("ERROR: could not get clock %s:%s(%i)\n",
106 np->full_name, name ? name : "", index);
111 * No matching clock found on this node. If the parent node
112 * has a "clock-ranges" property, then we can try one of its
116 if (np && !of_get_property(np, "clock-ranges", NULL))
122 EXPORT_SYMBOL(of_clk_get_by_name);
126 * Find the correct struct clk for the device and connection ID.
127 * We do slightly fuzzy matching here:
128 * An entry with a NULL ID is assumed to be a wildcard.
129 * If an entry has a device ID, it must match
130 * If an entry has a connection ID, it must match
131 * Then we take the most specific entry - with the following
132 * order of precedence: dev+con > dev only > con only.
134 static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
136 struct clk_lookup *p, *cl = NULL;
137 int match, best_found = 0, best_possible = 0;
144 list_for_each_entry(p, &clocks, node) {
147 if (!dev_id || strcmp(p->dev_id, dev_id))
152 if (!con_id || strcmp(p->con_id, con_id))
157 if (match > best_found) {
159 if (match != best_possible)
168 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
170 struct clk_lookup *cl;
172 mutex_lock(&clocks_mutex);
173 cl = clk_find(dev_id, con_id);
174 if (cl && !__clk_get(cl->clk))
176 mutex_unlock(&clocks_mutex);
178 return cl ? cl->clk : ERR_PTR(-ENOENT);
180 EXPORT_SYMBOL(clk_get_sys);
182 struct clk *clk_get(struct device *dev, const char *con_id)
184 const char *dev_id = dev ? dev_name(dev) : NULL;
188 clk = of_clk_get_by_name(dev->of_node, con_id);
191 if (PTR_ERR(clk) == -EPROBE_DEFER)
195 return clk_get_sys(dev_id, con_id);
197 EXPORT_SYMBOL(clk_get);
199 void clk_put(struct clk *clk)
203 EXPORT_SYMBOL(clk_put);
205 void clkdev_add(struct clk_lookup *cl)
207 mutex_lock(&clocks_mutex);
208 list_add_tail(&cl->node, &clocks);
209 mutex_unlock(&clocks_mutex);
211 EXPORT_SYMBOL(clkdev_add);
213 void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
215 mutex_lock(&clocks_mutex);
217 list_add_tail(&cl->node, &clocks);
220 mutex_unlock(&clocks_mutex);
223 #define MAX_DEV_ID 20
224 #define MAX_CON_ID 16
226 struct clk_lookup_alloc {
227 struct clk_lookup cl;
228 char dev_id[MAX_DEV_ID];
229 char con_id[MAX_CON_ID];
232 static struct clk_lookup * __init_refok
233 vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt,
236 struct clk_lookup_alloc *cla;
238 cla = __clkdev_alloc(sizeof(*cla));
244 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
245 cla->cl.con_id = cla->con_id;
249 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
250 cla->cl.dev_id = cla->dev_id;
256 struct clk_lookup * __init_refok
257 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
259 struct clk_lookup *cl;
262 va_start(ap, dev_fmt);
263 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
268 EXPORT_SYMBOL(clkdev_alloc);
270 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
273 struct clk *r = clk_get(dev, id);
274 struct clk_lookup *l;
279 l = clkdev_alloc(r, alias, alias_dev_name);
286 EXPORT_SYMBOL(clk_add_alias);
289 * clkdev_drop - remove a clock dynamically allocated
291 void clkdev_drop(struct clk_lookup *cl)
293 mutex_lock(&clocks_mutex);
295 mutex_unlock(&clocks_mutex);
298 EXPORT_SYMBOL(clkdev_drop);
301 * clk_register_clkdev - register one clock lookup for a struct clk
302 * @clk: struct clk to associate with all clk_lookups
303 * @con_id: connection ID string on device
304 * @dev_id: format string describing device name
306 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
309 * To make things easier for mass registration, we detect error clks
310 * from a previous clk_register() call, and return the error code for
311 * those. This is to permit this function to be called immediately
312 * after clk_register().
314 int clk_register_clkdev(struct clk *clk, const char *con_id,
315 const char *dev_fmt, ...)
317 struct clk_lookup *cl;
323 va_start(ap, dev_fmt);
324 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
336 * clk_register_clkdevs - register a set of clk_lookup for a struct clk
337 * @clk: struct clk to associate with all clk_lookups
338 * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized
339 * @num: number of clk_lookup structures to register
341 * To make things easier for mass registration, we detect error clks
342 * from a previous clk_register() call, and return the error code for
343 * those. This is to permit this function to be called immediately
344 * after clk_register().
346 int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num)
353 for (i = 0; i < num; i++, cl++) {
360 EXPORT_SYMBOL(clk_register_clkdevs);