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>
24 static LIST_HEAD(clocks
);
25 static DEFINE_MUTEX(clocks_mutex
);
27 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
28 struct clk
*of_clk_get(struct device_node
*np
, int index
)
30 struct of_phandle_args clkspec
;
35 return ERR_PTR(-EINVAL
);
37 rc
= of_parse_phandle_with_args(np
, "clocks", "#clock-cells", index
,
42 clk
= of_clk_get_from_provider(&clkspec
);
43 of_node_put(clkspec
.np
);
46 EXPORT_SYMBOL(of_clk_get
);
49 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
50 * @np: pointer to clock consumer node
51 * @name: name of consumer's clock input, or NULL for the first clock reference
53 * This function parses the clocks and clock-names properties,
54 * and uses them to look up the struct clk from the registered list of clock
57 struct clk
*of_clk_get_by_name(struct device_node
*np
, const char *name
)
59 struct clk
*clk
= ERR_PTR(-ENOENT
);
61 /* Walk up the tree of devices looking for a clock that matches */
66 * For named clocks, first look up the name in the
67 * "clock-names" property. If it cannot be found, then
68 * index will be an error code, and of_clk_get() will fail.
71 index
= of_property_match_string(np
, "clock-names", name
);
72 clk
= of_clk_get(np
, index
);
75 else if (name
&& index
>= 0) {
76 pr_err("ERROR: could not get clock %s:%s(%i)\n",
77 np
->full_name
, name
? name
: "", index
);
82 * No matching clock found on this node. If the parent node
83 * has a "clock-ranges" property, then we can try one of its
87 if (np
&& !of_get_property(np
, "clock-ranges", NULL
))
93 EXPORT_SYMBOL(of_clk_get_by_name
);
97 * Find the correct struct clk for the device and connection ID.
98 * We do slightly fuzzy matching here:
99 * An entry with a NULL ID is assumed to be a wildcard.
100 * If an entry has a device ID, it must match
101 * If an entry has a connection ID, it must match
102 * Then we take the most specific entry - with the following
103 * order of precedence: dev+con > dev only > con only.
105 static struct clk_lookup
*clk_find(const char *dev_id
, const char *con_id
)
107 struct clk_lookup
*p
, *cl
= NULL
;
108 int match
, best_found
= 0, best_possible
= 0;
115 list_for_each_entry(p
, &clocks
, node
) {
118 if (!dev_id
|| strcmp(p
->dev_id
, dev_id
))
123 if (!con_id
|| strcmp(p
->con_id
, con_id
))
128 if (match
> best_found
) {
130 if (match
!= best_possible
)
139 struct clk
*clk_get_sys(const char *dev_id
, const char *con_id
)
141 struct clk_lookup
*cl
;
143 mutex_lock(&clocks_mutex
);
144 cl
= clk_find(dev_id
, con_id
);
145 if (cl
&& !__clk_get(cl
->clk
))
147 mutex_unlock(&clocks_mutex
);
149 return cl
? cl
->clk
: ERR_PTR(-ENOENT
);
151 EXPORT_SYMBOL(clk_get_sys
);
153 struct clk
*clk_get(struct device
*dev
, const char *con_id
)
155 const char *dev_id
= dev
? dev_name(dev
) : NULL
;
159 clk
= of_clk_get_by_name(dev
->of_node
, con_id
);
160 if (!IS_ERR(clk
) && __clk_get(clk
))
164 return clk_get_sys(dev_id
, con_id
);
166 EXPORT_SYMBOL(clk_get
);
168 void clk_put(struct clk
*clk
)
172 EXPORT_SYMBOL(clk_put
);
174 static void devm_clk_release(struct device
*dev
, void *res
)
176 clk_put(*(struct clk
**)res
);
179 struct clk
*devm_clk_get(struct device
*dev
, const char *id
)
181 struct clk
**ptr
, *clk
;
183 ptr
= devres_alloc(devm_clk_release
, sizeof(*ptr
), GFP_KERNEL
);
185 return ERR_PTR(-ENOMEM
);
187 clk
= clk_get(dev
, id
);
190 devres_add(dev
, ptr
);
197 EXPORT_SYMBOL(devm_clk_get
);
199 static int devm_clk_match(struct device
*dev
, void *res
, void *data
)
201 struct clk
**c
= res
;
209 void devm_clk_put(struct device
*dev
, struct clk
*clk
)
213 ret
= devres_destroy(dev
, devm_clk_release
, devm_clk_match
, clk
);
217 EXPORT_SYMBOL(devm_clk_put
);
219 void clkdev_add(struct clk_lookup
*cl
)
221 mutex_lock(&clocks_mutex
);
222 list_add_tail(&cl
->node
, &clocks
);
223 mutex_unlock(&clocks_mutex
);
225 EXPORT_SYMBOL(clkdev_add
);
227 void __init
clkdev_add_table(struct clk_lookup
*cl
, size_t num
)
229 mutex_lock(&clocks_mutex
);
231 list_add_tail(&cl
->node
, &clocks
);
234 mutex_unlock(&clocks_mutex
);
237 #define MAX_DEV_ID 20
238 #define MAX_CON_ID 16
240 struct clk_lookup_alloc
{
241 struct clk_lookup cl
;
242 char dev_id
[MAX_DEV_ID
];
243 char con_id
[MAX_CON_ID
];
246 static struct clk_lookup
* __init_refok
247 vclkdev_alloc(struct clk
*clk
, const char *con_id
, const char *dev_fmt
,
250 struct clk_lookup_alloc
*cla
;
252 cla
= __clkdev_alloc(sizeof(*cla
));
258 strlcpy(cla
->con_id
, con_id
, sizeof(cla
->con_id
));
259 cla
->cl
.con_id
= cla
->con_id
;
263 vscnprintf(cla
->dev_id
, sizeof(cla
->dev_id
), dev_fmt
, ap
);
264 cla
->cl
.dev_id
= cla
->dev_id
;
270 struct clk_lookup
* __init_refok
271 clkdev_alloc(struct clk
*clk
, const char *con_id
, const char *dev_fmt
, ...)
273 struct clk_lookup
*cl
;
276 va_start(ap
, dev_fmt
);
277 cl
= vclkdev_alloc(clk
, con_id
, dev_fmt
, ap
);
282 EXPORT_SYMBOL(clkdev_alloc
);
284 int clk_add_alias(const char *alias
, const char *alias_dev_name
, char *id
,
287 struct clk
*r
= clk_get(dev
, id
);
288 struct clk_lookup
*l
;
293 l
= clkdev_alloc(r
, alias
, alias_dev_name
);
300 EXPORT_SYMBOL(clk_add_alias
);
303 * clkdev_drop - remove a clock dynamically allocated
305 void clkdev_drop(struct clk_lookup
*cl
)
307 mutex_lock(&clocks_mutex
);
309 mutex_unlock(&clocks_mutex
);
312 EXPORT_SYMBOL(clkdev_drop
);
315 * clk_register_clkdev - register one clock lookup for a struct clk
316 * @clk: struct clk to associate with all clk_lookups
317 * @con_id: connection ID string on device
318 * @dev_id: format string describing device name
320 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
323 * To make things easier for mass registration, we detect error clks
324 * from a previous clk_register() call, and return the error code for
325 * those. This is to permit this function to be called immediately
326 * after clk_register().
328 int clk_register_clkdev(struct clk
*clk
, const char *con_id
,
329 const char *dev_fmt
, ...)
331 struct clk_lookup
*cl
;
337 va_start(ap
, dev_fmt
);
338 cl
= vclkdev_alloc(clk
, con_id
, dev_fmt
, ap
);
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
);