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
);
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