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>
22 #include <linux/clk-provider.h>
27 static LIST_HEAD(clocks);
28 static DEFINE_MUTEX(clocks_mutex);
30 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
31 static struct clk *__of_clk_get(struct device_node *np, int index,
32 const char *dev_id, const char *con_id)
34 struct of_phandle_args clkspec;
39 return ERR_PTR(-EINVAL);
41 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
46 clk = __of_clk_get_from_provider(&clkspec, dev_id, con_id);
47 of_node_put(clkspec.np);
52 struct clk *of_clk_get(struct device_node *np, int index)
54 return __of_clk_get(np, index, np->full_name, NULL);
56 EXPORT_SYMBOL(of_clk_get);
58 static struct clk *__of_clk_get_by_name(struct device_node *np,
62 struct clk *clk = ERR_PTR(-ENOENT);
64 /* Walk up the tree of devices looking for a clock that matches */
69 * For named clocks, first look up the name in the
70 * "clock-names" property. If it cannot be found, then
71 * index will be an error code, and of_clk_get() will fail.
74 index = of_property_match_string(np, "clock-names", name);
75 clk = __of_clk_get(np, index, dev_id, name);
78 } else if (name && index >= 0) {
79 if (PTR_ERR(clk) != -EPROBE_DEFER)
80 pr_err("ERROR: could not get clock %s:%s(%i)\n",
81 np->full_name, name ? name : "", index);
86 * No matching clock found on this node. If the parent node
87 * has a "clock-ranges" property, then we can try one of its
91 if (np && !of_get_property(np, "clock-ranges", NULL))
99 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
100 * @np: pointer to clock consumer node
101 * @name: name of consumer's clock input, or NULL for the first clock reference
103 * This function parses the clocks and clock-names properties,
104 * and uses them to look up the struct clk from the registered list of clock
107 struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
110 return ERR_PTR(-ENOENT);
112 return __of_clk_get_by_name(np, np->full_name, name);
114 EXPORT_SYMBOL(of_clk_get_by_name);
116 #else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */
118 static struct clk *__of_clk_get_by_name(struct device_node *np,
122 return ERR_PTR(-ENOENT);
127 * Find the correct struct clk for the device and connection ID.
128 * We do slightly fuzzy matching here:
129 * An entry with a NULL ID is assumed to be a wildcard.
130 * If an entry has a device ID, it must match
131 * If an entry has a connection ID, it must match
132 * Then we take the most specific entry - with the following
133 * order of precedence: dev+con > dev only > con only.
135 static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
137 struct clk_lookup *p, *cl = NULL;
138 int match, best_found = 0, best_possible = 0;
145 list_for_each_entry(p, &clocks, node) {
148 if (!dev_id || strcmp(p->dev_id, dev_id))
153 if (!con_id || strcmp(p->con_id, con_id))
158 if (match > best_found) {
160 if (match != best_possible)
169 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
171 struct clk_lookup *cl;
172 struct clk *clk = NULL;
174 mutex_lock(&clocks_mutex);
176 cl = clk_find(dev_id, con_id);
180 clk = __clk_create_clk(__clk_get_hw(cl->clk), dev_id, con_id);
184 if (!__clk_get(clk)) {
191 mutex_unlock(&clocks_mutex);
193 return cl ? clk : ERR_PTR(-ENOENT);
195 EXPORT_SYMBOL(clk_get_sys);
197 struct clk *clk_get(struct device *dev, const char *con_id)
199 const char *dev_id = dev ? dev_name(dev) : NULL;
203 clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
204 if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
208 return clk_get_sys(dev_id, con_id);
210 EXPORT_SYMBOL(clk_get);
212 void clk_put(struct clk *clk)
216 EXPORT_SYMBOL(clk_put);
218 void clkdev_add(struct clk_lookup *cl)
220 mutex_lock(&clocks_mutex);
221 list_add_tail(&cl->node, &clocks);
222 mutex_unlock(&clocks_mutex);
224 EXPORT_SYMBOL(clkdev_add);
226 void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
228 mutex_lock(&clocks_mutex);
230 list_add_tail(&cl->node, &clocks);
233 mutex_unlock(&clocks_mutex);
236 #define MAX_DEV_ID 20
237 #define MAX_CON_ID 16
239 struct clk_lookup_alloc {
240 struct clk_lookup cl;
241 char dev_id[MAX_DEV_ID];
242 char con_id[MAX_CON_ID];
245 static struct clk_lookup * __init_refok
246 vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt,
249 struct clk_lookup_alloc *cla;
251 cla = __clkdev_alloc(sizeof(*cla));
257 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
258 cla->cl.con_id = cla->con_id;
262 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
263 cla->cl.dev_id = cla->dev_id;
269 struct clk_lookup * __init_refok
270 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
272 struct clk_lookup *cl;
275 va_start(ap, dev_fmt);
276 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
281 EXPORT_SYMBOL(clkdev_alloc);
283 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
286 struct clk *r = clk_get(dev, id);
287 struct clk_lookup *l;
292 l = clkdev_alloc(r, alias, alias_dev_name);
299 EXPORT_SYMBOL(clk_add_alias);
302 * clkdev_drop - remove a clock dynamically allocated
304 void clkdev_drop(struct clk_lookup *cl)
306 mutex_lock(&clocks_mutex);
308 mutex_unlock(&clocks_mutex);
311 EXPORT_SYMBOL(clkdev_drop);
314 * clk_register_clkdev - register one clock lookup for a struct clk
315 * @clk: struct clk to associate with all clk_lookups
316 * @con_id: connection ID string on device
317 * @dev_id: format string describing device name
319 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
322 * To make things easier for mass registration, we detect error clks
323 * from a previous clk_register() call, and return the error code for
324 * those. This is to permit this function to be called immediately
325 * after clk_register().
327 int clk_register_clkdev(struct clk *clk, const char *con_id,
328 const char *dev_fmt, ...)
330 struct clk_lookup *cl;
336 va_start(ap, dev_fmt);
337 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
347 EXPORT_SYMBOL(clk_register_clkdev);
350 * clk_register_clkdevs - register a set of clk_lookup for a struct clk
351 * @clk: struct clk to associate with all clk_lookups
352 * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized
353 * @num: number of clk_lookup structures to register
355 * To make things easier for mass registration, we detect error clks
356 * from a previous clk_register() call, and return the error code for
357 * those. This is to permit this function to be called immediately
358 * after clk_register().
360 int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num)
367 for (i = 0; i < num; i++, cl++) {
374 EXPORT_SYMBOL(clk_register_clkdevs);