1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/clk/clkdev.c
4 *
5 * Copyright (C) 2008 Russell King.
6 *
7 * Helper for the clk API to assist looking up a struct clk.
8 */
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/device.h>
12#include <linux/list.h>
13#include <linux/errno.h>
14#include <linux/err.h>
15#include <linux/string.h>
16#include <linux/mutex.h>
17#include <linux/clk.h>
18#include <linux/clkdev.h>
19#include <linux/clk-provider.h>
20#include <linux/of.h>
21
22#include "clk.h"
23
24static LIST_HEAD(clocks);
25static DEFINE_MUTEX(clocks_mutex);
26
27/*
28 * Find the correct struct clk for the device and connection ID.
29 * We do slightly fuzzy matching here:
30 * An entry with a NULL ID is assumed to be a wildcard.
31 * If an entry has a device ID, it must match
32 * If an entry has a connection ID, it must match
33 * Then we take the most specific entry - with the following
34 * order of precedence: dev+con > dev only > con only.
35 */
36static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
37{
38 struct clk_lookup *p, *cl = NULL;
39 int match, best_found = 0, best_possible = 0;
40
41 if (dev_id)
42 best_possible += 2;
43 if (con_id)
44 best_possible += 1;
45
46 lockdep_assert_held(&clocks_mutex);
47
48 list_for_each_entry(p, &clocks, node) {
49 match = 0;
50 if (p->dev_id) {
51 if (!dev_id || strcmp(p->dev_id, dev_id))
52 continue;
53 match += 2;
54 }
55 if (p->con_id) {
56 if (!con_id || strcmp(p->con_id, con_id))
57 continue;
58 match += 1;
59 }
60
61 if (match > best_found) {
62 cl = p;
63 if (match != best_possible)
64 best_found = match;
65 else
66 break;
67 }
68 }
69 return cl;
70}
71
72struct clk_hw *clk_find_hw(const char *dev_id, const char *con_id)
73{
74 struct clk_lookup *cl;
75 struct clk_hw *hw = ERR_PTR(error: -ENOENT);
76
77 mutex_lock(&clocks_mutex);
78 cl = clk_find(dev_id, con_id);
79 if (cl)
80 hw = cl->clk_hw;
81 mutex_unlock(lock: &clocks_mutex);
82
83 return hw;
84}
85
86static struct clk *__clk_get_sys(struct device *dev, const char *dev_id,
87 const char *con_id)
88{
89 struct clk_hw *hw = clk_find_hw(dev_id, con_id);
90
91 return clk_hw_create_clk(dev, hw, dev_id, con_id);
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(np: dev->of_node, index: 0, con_id);
107 if (!IS_ERR(ptr: hw) || PTR_ERR(ptr: 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(new: &cl->node, head: &clocks);
125 mutex_unlock(lock: &clocks_mutex);
126}
127
128void clkdev_add(struct clk_lookup *cl)
129{
130 if (!cl->clk_hw)
131 cl->clk_hw = __clk_get_hw(clk: 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(clk: cl->clk);
141 list_add_tail(new: &cl->node, head: &clocks);
142 cl++;
143 }
144 mutex_unlock(lock: &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(size: sizeof(*cla), GFP_KERNEL);
163 if (!cla)
164 return NULL;
165
166 cla->cl.clk_hw = hw;
167 if (con_id) {
168 strscpy(p: cla->con_id, q: con_id, size: sizeof(cla->con_id));
169 cla->cl.con_id = cla->con_id;
170 }
171
172 if (dev_fmt) {
173 vscnprintf(buf: cla->dev_id, size: sizeof(cla->dev_id), fmt: dev_fmt, args: 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
193/**
194 * clkdev_create - allocate and add a clkdev lookup structure
195 * @clk: struct clk to associate with all clk_lookups
196 * @con_id: connection ID string on device
197 * @dev_fmt: format string describing device name
198 *
199 * Returns a clk_lookup structure, which can be later unregistered and
200 * freed.
201 */
202struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id,
203 const char *dev_fmt, ...)
204{
205 struct clk_lookup *cl;
206 va_list ap;
207
208 va_start(ap, dev_fmt);
209 cl = vclkdev_create(hw: __clk_get_hw(clk), con_id, dev_fmt, ap);
210 va_end(ap);
211
212 return cl;
213}
214EXPORT_SYMBOL_GPL(clkdev_create);
215
216/**
217 * clkdev_hw_create - allocate and add a clkdev lookup structure
218 * @hw: struct clk_hw to associate with all clk_lookups
219 * @con_id: connection ID string on device
220 * @dev_fmt: format string describing device name
221 *
222 * Returns a clk_lookup structure, which can be later unregistered and
223 * freed.
224 */
225struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id,
226 const char *dev_fmt, ...)
227{
228 struct clk_lookup *cl;
229 va_list ap;
230
231 va_start(ap, dev_fmt);
232 cl = vclkdev_create(hw, con_id, dev_fmt, ap);
233 va_end(ap);
234
235 return cl;
236}
237EXPORT_SYMBOL_GPL(clkdev_hw_create);
238
239int clk_add_alias(const char *alias, const char *alias_dev_name,
240 const char *con_id, struct device *dev)
241{
242 struct clk *r = clk_get(dev, con_id);
243 struct clk_lookup *l;
244
245 if (IS_ERR(ptr: r))
246 return PTR_ERR(ptr: r);
247
248 l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL,
249 alias_dev_name);
250 clk_put(r);
251
252 return l ? 0 : -ENODEV;
253}
254EXPORT_SYMBOL(clk_add_alias);
255
256/*
257 * clkdev_drop - remove a clock dynamically allocated
258 */
259void clkdev_drop(struct clk_lookup *cl)
260{
261 mutex_lock(&clocks_mutex);
262 list_del(entry: &cl->node);
263 mutex_unlock(lock: &clocks_mutex);
264 kfree(objp: cl);
265}
266EXPORT_SYMBOL(clkdev_drop);
267
268static struct clk_lookup *__clk_register_clkdev(struct clk_hw *hw,
269 const char *con_id,
270 const char *dev_id, ...)
271{
272 struct clk_lookup *cl;
273 va_list ap;
274
275 va_start(ap, dev_id);
276 cl = vclkdev_create(hw, con_id, dev_fmt: dev_id, ap);
277 va_end(ap);
278
279 return cl;
280}
281
282static int do_clk_register_clkdev(struct clk_hw *hw,
283 struct clk_lookup **cl, const char *con_id, const char *dev_id)
284{
285 if (IS_ERR(ptr: hw))
286 return PTR_ERR(ptr: hw);
287 /*
288 * Since dev_id can be NULL, and NULL is handled specially, we must
289 * pass it as either a NULL format string, or with "%s".
290 */
291 if (dev_id)
292 *cl = __clk_register_clkdev(hw, con_id, dev_id: "%s", dev_id);
293 else
294 *cl = __clk_register_clkdev(hw, con_id, NULL);
295
296 return *cl ? 0 : -ENOMEM;
297}
298
299/**
300 * clk_register_clkdev - register one clock lookup for a struct clk
301 * @clk: struct clk to associate with all clk_lookups
302 * @con_id: connection ID string on device
303 * @dev_id: string describing device name
304 *
305 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
306 * clkdev.
307 *
308 * To make things easier for mass registration, we detect error clks
309 * from a previous clk_register() call, and return the error code for
310 * those. This is to permit this function to be called immediately
311 * after clk_register().
312 */
313int clk_register_clkdev(struct clk *clk, const char *con_id,
314 const char *dev_id)
315{
316 struct clk_lookup *cl;
317
318 if (IS_ERR(ptr: clk))
319 return PTR_ERR(ptr: clk);
320
321 return do_clk_register_clkdev(hw: __clk_get_hw(clk), cl: &cl, con_id,
322 dev_id);
323}
324EXPORT_SYMBOL(clk_register_clkdev);
325
326/**
327 * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw
328 * @hw: struct clk_hw to associate with all clk_lookups
329 * @con_id: connection ID string on device
330 * @dev_id: format string describing device name
331 *
332 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
333 * clkdev.
334 *
335 * To make things easier for mass registration, we detect error clk_hws
336 * from a previous clk_hw_register_*() call, and return the error code for
337 * those. This is to permit this function to be called immediately
338 * after clk_hw_register_*().
339 */
340int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id,
341 const char *dev_id)
342{
343 struct clk_lookup *cl;
344
345 return do_clk_register_clkdev(hw, cl: &cl, con_id, dev_id);
346}
347EXPORT_SYMBOL(clk_hw_register_clkdev);
348
349static void devm_clkdev_release(void *res)
350{
351 clkdev_drop(res);
352}
353
354/**
355 * devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw
356 * @dev: device this lookup is bound
357 * @hw: struct clk_hw to associate with all clk_lookups
358 * @con_id: connection ID string on device
359 * @dev_id: format string describing device name
360 *
361 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
362 * clkdev.
363 *
364 * To make things easier for mass registration, we detect error clk_hws
365 * from a previous clk_hw_register_*() call, and return the error code for
366 * those. This is to permit this function to be called immediately
367 * after clk_hw_register_*().
368 */
369int devm_clk_hw_register_clkdev(struct device *dev, struct clk_hw *hw,
370 const char *con_id, const char *dev_id)
371{
372 struct clk_lookup *cl;
373 int rval;
374
375 rval = do_clk_register_clkdev(hw, cl: &cl, con_id, dev_id);
376 if (rval)
377 return rval;
378
379 return devm_add_action_or_reset(dev, devm_clkdev_release, cl);
380}
381EXPORT_SYMBOL(devm_clk_hw_register_clkdev);
382

source code of linux/drivers/clk/clkdev.c