1/*
2 * drivers/clk/clkdev.c
3 *
4 * Copyright (C) 2008 Russell King.
5 *
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.
9 *
10 * Helper for the clk API to assist looking up a struct clk.
11 */
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>
23#include <linux/of.h>
24
25#include "clk.h"
26
27static LIST_HEAD(clocks);
28static DEFINE_MUTEX(clocks_mutex);
29
30/*
31 * Find the correct struct clk for the device and connection ID.
32 * We do slightly fuzzy matching here:
33 * An entry with a NULL ID is assumed to be a wildcard.
34 * If an entry has a device ID, it must match
35 * If an entry has a connection ID, it must match
36 * Then we take the most specific entry - with the following
37 * order of precedence: dev+con > dev only > con only.
38 */
39static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
40{
41 struct clk_lookup *p, *cl = NULL;
42 int match, best_found = 0, best_possible = 0;
43
44 if (dev_id)
45 best_possible += 2;
46 if (con_id)
47 best_possible += 1;
48
49 list_for_each_entry(p, &clocks, node) {
50 match = 0;
51 if (p->dev_id) {
52 if (!dev_id || strcmp(p->dev_id, dev_id))
53 continue;
54 match += 2;
55 }
56 if (p->con_id) {
57 if (!con_id || strcmp(p->con_id, con_id))
58 continue;
59 match += 1;
60 }
61
62 if (match > best_found) {
63 cl = p;
64 if (match != best_possible)
65 best_found = match;
66 else
67 break;
68 }
69 }
70 return cl;
71}
72
73static struct clk *__clk_get_sys(struct device *dev, const char *dev_id,
74 const char *con_id)
75{
76 struct clk_lookup *cl;
77 struct clk *clk = NULL;
78
79 mutex_lock(&clocks_mutex);
80
81 cl = clk_find(dev_id, con_id);
82 if (!cl)
83 goto out;
84
85 clk = clk_hw_create_clk(dev, cl->clk_hw, dev_id, con_id);
86 if (IS_ERR(clk))
87 cl = NULL;
88out:
89 mutex_unlock(&clocks_mutex);
90
91 return cl ? clk : ERR_PTR(-ENOENT);
92}
93
94struct clk *clk_get_sys(const char *dev_id, const char *con_id)
95{
96 return __clk_get_sys(NULL, dev_id, con_id);
97}
98EXPORT_SYMBOL(clk_get_sys);
99
100struct clk *clk_get(struct device *dev, const char *con_id)
101{
102 const char *dev_id = dev ? dev_name(dev) : NULL;
103 struct clk_hw *hw;
104
105 if (dev && dev->of_node) {
106 hw = of_clk_get_hw(dev->of_node, 0, con_id);
107 if (!IS_ERR(hw) || PTR_ERR(hw) == -EPROBE_DEFER)
108 return clk_hw_create_clk(dev, hw, dev_id, con_id);
109 }
110
111 return __clk_get_sys(dev, dev_id, con_id);
112}
113EXPORT_SYMBOL(clk_get);
114
115void clk_put(struct clk *clk)
116{
117 __clk_put(clk);
118}
119EXPORT_SYMBOL(clk_put);
120
121static void __clkdev_add(struct clk_lookup *cl)
122{
123 mutex_lock(&clocks_mutex);
124 list_add_tail(&cl->node, &clocks);
125 mutex_unlock(&clocks_mutex);
126}
127
128void clkdev_add(struct clk_lookup *cl)
129{
130 if (!cl->clk_hw)
131 cl->clk_hw = __clk_get_hw(cl->clk);
132 __clkdev_add(cl);
133}
134EXPORT_SYMBOL(clkdev_add);
135
136void clkdev_add_table(struct clk_lookup *cl, size_t num)
137{
138 mutex_lock(&clocks_mutex);
139 while (num--) {
140 cl->clk_hw = __clk_get_hw(cl->clk);
141 list_add_tail(&cl->node, &clocks);
142 cl++;
143 }
144 mutex_unlock(&clocks_mutex);
145}
146
147#define MAX_DEV_ID 20
148#define MAX_CON_ID 16
149
150struct clk_lookup_alloc {
151 struct clk_lookup cl;
152 char dev_id[MAX_DEV_ID];
153 char con_id[MAX_CON_ID];
154};
155
156static struct clk_lookup * __ref
157vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
158 va_list ap)
159{
160 struct clk_lookup_alloc *cla;
161
162 cla = kzalloc(sizeof(*cla), GFP_KERNEL);
163 if (!cla)
164 return NULL;
165
166 cla->cl.clk_hw = hw;
167 if (con_id) {
168 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
169 cla->cl.con_id = cla->con_id;
170 }
171
172 if (dev_fmt) {
173 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
174 cla->cl.dev_id = cla->dev_id;
175 }
176
177 return &cla->cl;
178}
179
180static struct clk_lookup *
181vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
182 va_list ap)
183{
184 struct clk_lookup *cl;
185
186 cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
187 if (cl)
188 __clkdev_add(cl);
189
190 return cl;
191}
192
193struct clk_lookup * __ref
194clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
195{
196 struct clk_lookup *cl;
197 va_list ap;
198
199 va_start(ap, dev_fmt);
200 cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap);
201 va_end(ap);
202
203 return cl;
204}
205EXPORT_SYMBOL(clkdev_alloc);
206
207struct clk_lookup *
208clkdev_hw_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, ...)
209{
210 struct clk_lookup *cl;
211 va_list ap;
212
213 va_start(ap, dev_fmt);
214 cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
215 va_end(ap);
216
217 return cl;
218}
219EXPORT_SYMBOL(clkdev_hw_alloc);
220
221/**
222 * clkdev_create - allocate and add a clkdev lookup structure
223 * @clk: struct clk to associate with all clk_lookups
224 * @con_id: connection ID string on device
225 * @dev_fmt: format string describing device name
226 *
227 * Returns a clk_lookup structure, which can be later unregistered and
228 * freed.
229 */
230struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id,
231 const char *dev_fmt, ...)
232{
233 struct clk_lookup *cl;
234 va_list ap;
235
236 va_start(ap, dev_fmt);
237 cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap);
238 va_end(ap);
239
240 return cl;
241}
242EXPORT_SYMBOL_GPL(clkdev_create);
243
244/**
245 * clkdev_hw_create - allocate and add a clkdev lookup structure
246 * @hw: struct clk_hw to associate with all clk_lookups
247 * @con_id: connection ID string on device
248 * @dev_fmt: format string describing device name
249 *
250 * Returns a clk_lookup structure, which can be later unregistered and
251 * freed.
252 */
253struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id,
254 const char *dev_fmt, ...)
255{
256 struct clk_lookup *cl;
257 va_list ap;
258
259 va_start(ap, dev_fmt);
260 cl = vclkdev_create(hw, con_id, dev_fmt, ap);
261 va_end(ap);
262
263 return cl;
264}
265EXPORT_SYMBOL_GPL(clkdev_hw_create);
266
267int clk_add_alias(const char *alias, const char *alias_dev_name,
268 const char *con_id, struct device *dev)
269{
270 struct clk *r = clk_get(dev, con_id);
271 struct clk_lookup *l;
272
273 if (IS_ERR(r))
274 return PTR_ERR(r);
275
276 l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL,
277 alias_dev_name);
278 clk_put(r);
279
280 return l ? 0 : -ENODEV;
281}
282EXPORT_SYMBOL(clk_add_alias);
283
284/*
285 * clkdev_drop - remove a clock dynamically allocated
286 */
287void clkdev_drop(struct clk_lookup *cl)
288{
289 mutex_lock(&clocks_mutex);
290 list_del(&cl->node);
291 mutex_unlock(&clocks_mutex);
292 kfree(cl);
293}
294EXPORT_SYMBOL(clkdev_drop);
295
296static struct clk_lookup *__clk_register_clkdev(struct clk_hw *hw,
297 const char *con_id,
298 const char *dev_id, ...)
299{
300 struct clk_lookup *cl;
301 va_list ap;
302
303 va_start(ap, dev_id);
304 cl = vclkdev_create(hw, con_id, dev_id, ap);
305 va_end(ap);
306
307 return cl;
308}
309
310static int do_clk_register_clkdev(struct clk_hw *hw,
311 struct clk_lookup **cl, const char *con_id, const char *dev_id)
312{
313 if (IS_ERR(hw))
314 return PTR_ERR(hw);
315 /*
316 * Since dev_id can be NULL, and NULL is handled specially, we must
317 * pass it as either a NULL format string, or with "%s".
318 */
319 if (dev_id)
320 *cl = __clk_register_clkdev(hw, con_id, "%s", dev_id);
321 else
322 *cl = __clk_register_clkdev(hw, con_id, NULL);
323
324 return *cl ? 0 : -ENOMEM;
325}
326
327/**
328 * clk_register_clkdev - register one clock lookup for a struct clk
329 * @clk: struct clk to associate with all clk_lookups
330 * @con_id: connection ID string on device
331 * @dev_id: string describing device name
332 *
333 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
334 * clkdev.
335 *
336 * To make things easier for mass registration, we detect error clks
337 * from a previous clk_register() call, and return the error code for
338 * those. This is to permit this function to be called immediately
339 * after clk_register().
340 */
341int clk_register_clkdev(struct clk *clk, const char *con_id,
342 const char *dev_id)
343{
344 struct clk_lookup *cl;
345
346 if (IS_ERR(clk))
347 return PTR_ERR(clk);
348
349 return do_clk_register_clkdev(__clk_get_hw(clk), &cl, con_id,
350 dev_id);
351}
352EXPORT_SYMBOL(clk_register_clkdev);
353
354/**
355 * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw
356 * @hw: struct clk_hw to associate with all clk_lookups
357 * @con_id: connection ID string on device
358 * @dev_id: format string describing device name
359 *
360 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
361 * clkdev.
362 *
363 * To make things easier for mass registration, we detect error clk_hws
364 * from a previous clk_hw_register_*() call, and return the error code for
365 * those. This is to permit this function to be called immediately
366 * after clk_hw_register_*().
367 */
368int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id,
369 const char *dev_id)
370{
371 struct clk_lookup *cl;
372
373 return do_clk_register_clkdev(hw, &cl, con_id, dev_id);
374}
375EXPORT_SYMBOL(clk_hw_register_clkdev);
376
377static void devm_clkdev_release(struct device *dev, void *res)
378{
379 clkdev_drop(*(struct clk_lookup **)res);
380}
381
382static int devm_clk_match_clkdev(struct device *dev, void *res, void *data)
383{
384 struct clk_lookup **l = res;
385
386 return *l == data;
387}
388
389/**
390 * devm_clk_release_clkdev - Resource managed clkdev lookup release
391 * @dev: device this lookup is bound
392 * @con_id: connection ID string on device
393 * @dev_id: format string describing device name
394 *
395 * Drop the clkdev lookup created with devm_clk_hw_register_clkdev.
396 * Normally this function will not need to be called and the resource
397 * management code will ensure that the resource is freed.
398 */
399void devm_clk_release_clkdev(struct device *dev, const char *con_id,
400 const char *dev_id)
401{
402 struct clk_lookup *cl;
403 int rval;
404
405 cl = clk_find(dev_id, con_id);
406 WARN_ON(!cl);
407 rval = devres_release(dev, devm_clkdev_release,
408 devm_clk_match_clkdev, cl);
409 WARN_ON(rval);
410}
411EXPORT_SYMBOL(devm_clk_release_clkdev);
412
413/**
414 * devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw
415 * @dev: device this lookup is bound
416 * @hw: struct clk_hw to associate with all clk_lookups
417 * @con_id: connection ID string on device
418 * @dev_id: format string describing device name
419 *
420 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
421 * clkdev.
422 *
423 * To make things easier for mass registration, we detect error clk_hws
424 * from a previous clk_hw_register_*() call, and return the error code for
425 * those. This is to permit this function to be called immediately
426 * after clk_hw_register_*().
427 */
428int devm_clk_hw_register_clkdev(struct device *dev, struct clk_hw *hw,
429 const char *con_id, const char *dev_id)
430{
431 int rval = -ENOMEM;
432 struct clk_lookup **cl;
433
434 cl = devres_alloc(devm_clkdev_release, sizeof(*cl), GFP_KERNEL);
435 if (cl) {
436 rval = do_clk_register_clkdev(hw, cl, con_id, dev_id);
437 if (!rval)
438 devres_add(dev, cl);
439 else
440 devres_free(cl);
441 }
442 return rval;
443}
444EXPORT_SYMBOL(devm_clk_hw_register_clkdev);
445