aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/clk/clkdev.c
blob: 7513411140b693ecdb1d4c825de69e0e9e679d15 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
/*
 * drivers/clk/clkdev.c
 *
 *  Copyright (C) 2008 Russell King.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Helper for the clk API to assist looking up a struct clk.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/mutex.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/of.h>

#include "clk.h"

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);

#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
static struct clk *__of_clk_get(struct device_node *np, int index,
			       const char *dev_id, const char *con_id)
{
	struct of_phandle_args clkspec;
	struct clk *clk;
	int rc;

	if (index < 0)
		return ERR_PTR(-EINVAL);

	rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
					&clkspec);
	if (rc)
		return ERR_PTR(rc);

	clk = __of_clk_get_from_provider(&clkspec, dev_id, con_id);
	of_node_put(clkspec.np);

	return clk;
}

struct clk *of_clk_get(struct device_node *np, int index)
{
	return __of_clk_get(np, index, np->full_name, NULL);
}
EXPORT_SYMBOL(of_clk_get);

static struct clk *__of_clk_get_by_name(struct device_node *np,
					const char *dev_id,
					const char *name)
{
	struct clk *clk = ERR_PTR(-ENOENT);

	/* Walk up the tree of devices looking for a clock that matches */
	while (np) {
		int index = 0;

		/*
		 * For named clocks, first look up the name in the
		 * "clock-names" property.  If it cannot be found, then
		 * index will be an error code, and of_clk_get() will fail.
		 */
		if (name)
			index = of_property_match_string(np, "clock-names", name);
		clk = __of_clk_get(np, index, dev_id, name);
		if (!IS_ERR(clk)) {
			break;
		} else if (name && index >= 0) {
			if (PTR_ERR(clk) != -EPROBE_DEFER)
				pr_err("ERROR: could not get clock %pOF:%s(%i)\n",
					np, name ? name : "", index);
			return clk;
		}

		/*
		 * No matching clock found on this node.  If the parent node
		 * has a "clock-ranges" property, then we can try one of its
		 * clocks.
		 */
		np = np->parent;
		if (np && !of_get_property(np, "clock-ranges", NULL))
			break;
	}

	return clk;
}

/**
 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
 * @np: pointer to clock consumer node
 * @name: name of consumer's clock input, or NULL for the first clock reference
 *
 * This function parses the clocks and clock-names properties,
 * and uses them to look up the struct clk from the registered list of clock
 * providers.
 */
struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
{
	if (!np)
		return ERR_PTR(-ENOENT);

	return __of_clk_get_by_name(np, np->full_name, name);
}
EXPORT_SYMBOL(of_clk_get_by_name);

#else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */

static struct clk *__of_clk_get_by_name(struct device_node *np,
					const char *dev_id,
					const char *name)
{
	return ERR_PTR(-ENOENT);
}
#endif

/*
 * Find the correct struct clk for the device and connection ID.
 * We do slightly fuzzy matching here:
 *  An entry with a NULL ID is assumed to be a wildcard.
 *  If an entry has a device ID, it must match
 *  If an entry has a connection ID, it must match
 * Then we take the most specific entry - with the following
 * order of precedence: dev+con > dev only > con only.
 */
static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
{
	struct clk_lookup *p, *cl = NULL;
	int match, best_found = 0, best_possible = 0;

	if (dev_id)
		best_possible += 2;
	if (con_id)
		best_possible += 1;

	list_for_each_entry(p, &clocks, node) {
		match = 0;
		if (p->dev_id) {
			if (!dev_id || strcmp(p->dev_id, dev_id))
				continue;
			match += 2;
		}
		if (p->con_id) {
			if (!con_id || strcmp(p->con_id, con_id))
				continue;
			match += 1;
		}

		if (match > best_found) {
			cl = p;
			if (match != best_possible)
				best_found = match;
			else
				break;
		}
	}
	return cl;
}

struct clk *clk_get_sys(const char *dev_id, const char *con_id)
{
	struct clk_lookup *cl;
	struct clk *clk = NULL;

	mutex_lock(&clocks_mutex);

	cl = clk_find(dev_id, con_id);
	if (!cl)
		goto out;

	clk = __clk_create_clk(cl->clk_hw, dev_id, con_id);
	if (IS_ERR(clk))
		goto out;

	if (!__clk_get(clk)) {
		__clk_free_clk(clk);
		cl = NULL;
		goto out;
	}

out:
	mutex_unlock(&clocks_mutex);

	return cl ? clk : ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL(clk_get_sys);

struct clk *clk_get(struct device *dev, const char *con_id)
{
	const char *dev_id = dev ? dev_name(dev) : NULL;
	struct clk *clk;

	if (dev) {
		clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
		if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
			return clk;
	}

	return clk_get_sys(dev_id, con_id);
}
EXPORT_SYMBOL(clk_get);

void clk_put(struct clk *clk)
{
	__clk_put(clk);
}
EXPORT_SYMBOL(clk_put);

static void __clkdev_add(struct clk_lookup *cl)
{
	mutex_lock(&clocks_mutex);
	list_add_tail(&cl->node, &clocks);
	mutex_unlock(&clocks_mutex);
}

void clkdev_add(struct clk_lookup *cl)
{
	if (!cl->clk_hw)
		cl->clk_hw = __clk_get_hw(cl->clk);
	__clkdev_add(cl);
}
EXPORT_SYMBOL(clkdev_add);

void clkdev_add_table(struct clk_lookup *cl, size_t num)
{
	mutex_lock(&clocks_mutex);
	while (num--) {
		cl->clk_hw = __clk_get_hw(cl->clk);
		list_add_tail(&cl->node, &clocks);
		cl++;
	}
	mutex_unlock(&clocks_mutex);
}

#define MAX_DEV_ID	20
#define MAX_CON_ID	16

struct clk_lookup_alloc {
	struct clk_lookup cl;
	char	dev_id[MAX_DEV_ID];
	char	con_id[MAX_CON_ID];
};

static struct clk_lookup * __ref
vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
	va_list ap)
{
	struct clk_lookup_alloc *cla;

	cla = kzalloc(sizeof(*cla), GFP_KERNEL);
	if (!cla)
		return NULL;

	cla->cl.clk_hw = hw;
	if (con_id) {
		strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
		cla->cl.con_id = cla->con_id;
	}

	if (dev_fmt) {
		vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
		cla->cl.dev_id = cla->dev_id;
	}

	return &cla->cl;
}

static struct clk_lookup *
vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
	va_list ap)
{
	struct clk_lookup *cl;

	cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
	if (cl)
		__clkdev_add(cl);

	return cl;
}

struct clk_lookup * __ref
clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_fmt);
	cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap);
	va_end(ap);

	return cl;
}
EXPORT_SYMBOL(clkdev_alloc);

struct clk_lookup *
clkdev_hw_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, ...)
{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_fmt);
	cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
	va_end(ap);

	return cl;
}
EXPORT_SYMBOL(clkdev_hw_alloc);

/**
 * clkdev_create - allocate and add a clkdev lookup structure
 * @clk: struct clk to associate with all clk_lookups
 * @con_id: connection ID string on device
 * @dev_fmt: format string describing device name
 *
 * Returns a clk_lookup structure, which can be later unregistered and
 * freed.
 */
struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id,
	const char *dev_fmt, ...)
{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_fmt);
	cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap);
	va_end(ap);

	return cl;
}
EXPORT_SYMBOL_GPL(clkdev_create);

/**
 * clkdev_hw_create - allocate and add a clkdev lookup structure
 * @hw: struct clk_hw to associate with all clk_lookups
 * @con_id: connection ID string on device
 * @dev_fmt: format string describing device name
 *
 * Returns a clk_lookup structure, which can be later unregistered and
 * freed.
 */
struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id,
	const char *dev_fmt, ...)
{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_fmt);
	cl = vclkdev_create(hw, con_id, dev_fmt, ap);
	va_end(ap);

	return cl;
}
EXPORT_SYMBOL_GPL(clkdev_hw_create);

int clk_add_alias(const char *alias, const char *alias_dev_name,
	const char *con_id, struct device *dev)
{
	struct clk *r = clk_get(dev, con_id);
	struct clk_lookup *l;

	if (IS_ERR(r))
		return PTR_ERR(r);

	l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL,
			  alias_dev_name);
	clk_put(r);

	return l ? 0 : -ENODEV;
}
EXPORT_SYMBOL(clk_add_alias);

/*
 * clkdev_drop - remove a clock dynamically allocated
 */
void clkdev_drop(struct clk_lookup *cl)
{
	mutex_lock(&clocks_mutex);
	list_del(&cl->node);
	mutex_unlock(&clocks_mutex);
	kfree(cl);
}
EXPORT_SYMBOL(clkdev_drop);

static struct clk_lookup *__clk_register_clkdev(struct clk_hw *hw,
						const char *con_id,
						const char *dev_id, ...)
{
	struct clk_lookup *cl;
	va_list ap;

	va_start(ap, dev_id);
	cl = vclkdev_create(hw, con_id, dev_id, ap);
	va_end(ap);

	return cl;
}

/**
 * clk_register_clkdev - register one clock lookup for a struct clk
 * @clk: struct clk to associate with all clk_lookups
 * @con_id: connection ID string on device
 * @dev_id: string describing device name
 *
 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
 * clkdev.
 *
 * To make things easier for mass registration, we detect error clks
 * from a previous clk_register() call, and return the error code for
 * those.  This is to permit this function to be called immediately
 * after clk_register().
 */
int clk_register_clkdev(struct clk *clk, const char *con_id,
	const char *dev_id)
{
	struct clk_lookup *cl;

	if (IS_ERR(clk))
		return PTR_ERR(clk);

	/*
	 * Since dev_id can be NULL, and NULL is handled specially, we must
	 * pass it as either a NULL format string, or with "%s".
	 */
	if (dev_id)
		cl = __clk_register_clkdev(__clk_get_hw(clk), con_id, "%s",
					   dev_id);
	else
		cl = __clk_register_clkdev(__clk_get_hw(clk), con_id, NULL);

	return cl ? 0 : -ENOMEM;
}
EXPORT_SYMBOL(clk_register_clkdev);

/**
 * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw
 * @hw: struct clk_hw to associate with all clk_lookups
 * @con_id: connection ID string on device
 * @dev_id: format string describing device name
 *
 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
 * clkdev.
 *
 * To make things easier for mass registration, we detect error clk_hws
 * from a previous clk_hw_register_*() call, and return the error code for
 * those.  This is to permit this function to be called immediately
 * after clk_hw_register_*().
 */
int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id,
	const char *dev_id)
{
	struct clk_lookup *cl;

	if (IS_ERR(hw))
		return PTR_ERR(hw);

	/*
	 * Since dev_id can be NULL, and NULL is handled specially, we must
	 * pass it as either a NULL format string, or with "%s".
	 */
	if (dev_id)
		cl = __clk_register_clkdev(hw, con_id, "%s", dev_id);
	else
		cl = __clk_register_clkdev(hw, con_id, NULL);

	return cl ? 0 : -ENOMEM;
}
EXPORT_SYMBOL(clk_hw_register_clkdev);

Privacy Policy