summaryrefslogtreecommitdiffstats
path: root/drivers/clk/clk.c
blob: 19377b893c35363b864c8e9ceee21d4926c563e8 (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
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
/*
 * clk.c - generic barebox clock support. Based on Linux clk support
 *
 * Copyright (c) 2012 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */
#include <common.h>
#include <errno.h>
#include <malloc.h>
#include <stringlist.h>
#include <complete.h>
#include <linux/clk.h>
#include <linux/err.h>

static LIST_HEAD(clks);

static int clk_parent_enable(struct clk *clk)
{
	struct clk *parent = clk_get_parent(clk);

	if (!IS_ERR_OR_NULL(parent))
		return clk_enable(parent);

	return 0;
}

static void clk_parent_disable(struct clk *clk)
{
	struct clk *parent = clk_get_parent(clk);

	if (!IS_ERR_OR_NULL(parent))
		clk_disable(parent);
}

int clk_enable(struct clk *clk)
{
	int ret;

	if (!clk)
		return 0;

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

	if (!clk->enable_count) {
		ret = clk_parent_enable(clk);
		if (ret)
			return ret;

		if (clk->ops->enable) {
			ret = clk->ops->enable(clk);
			if (ret) {
				clk_parent_disable(clk);
				return ret;
			}
		}
	}

	clk->enable_count++;

	return 0;
}

void clk_disable(struct clk *clk)
{
	if (!clk)
		return;

	if (IS_ERR(clk))
		return;

	if (!clk->enable_count)
		return;

	clk->enable_count--;

	if (!clk->enable_count) {
		if (clk->ops->disable)
			clk->ops->disable(clk);

		clk_parent_disable(clk);
	}
}

unsigned long clk_get_rate(struct clk *clk)
{
	struct clk *parent;
	unsigned long parent_rate = 0;

	if (!clk)
		return 0;

	if (IS_ERR(clk))
		return 0;

	parent = clk_get_parent(clk);


	if (!IS_ERR_OR_NULL(parent))
		parent_rate = clk_get_rate(parent);

	if (clk->ops->recalc_rate)
		return clk->ops->recalc_rate(clk, parent_rate);

	return parent_rate;
}

long clk_round_rate(struct clk *clk, unsigned long rate)
{
	unsigned long parent_rate = 0;
	struct clk *parent;

	if (!clk)
		return 0;

	if (IS_ERR(clk))
		return 0;

	parent = clk_get_parent(clk);
	if (parent)
		parent_rate = clk_get_rate(parent);

	if (clk->ops->round_rate)
		return clk->ops->round_rate(clk, rate, &parent_rate);

	return clk_get_rate(clk);
}

int clk_set_rate(struct clk *clk, unsigned long rate)
{
	struct clk *parent;
	unsigned long parent_rate = 0;

	if (!clk)
		return 0;

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

	parent = clk_get_parent(clk);
	if (parent)
		parent_rate = clk_get_rate(parent);

	if (clk->ops->set_rate)
		return clk->ops->set_rate(clk, rate, parent_rate);

	return -ENOSYS;
}

struct clk *clk_lookup(const char *name)
{
	struct clk *c;

	if (!name)
		return ERR_PTR(-ENODEV);

	list_for_each_entry(c, &clks, list) {
		if (!strcmp(c->name, name))
			return c;
	}

	return ERR_PTR(-ENODEV);
}

int clk_set_parent(struct clk *clk, struct clk *parent)
{
	int i;

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

	if (!clk->num_parents)
		return -EINVAL;
	if (!clk->ops->set_parent)
		return -EINVAL;

	for (i = 0; i < clk->num_parents; i++) {
		if (IS_ERR_OR_NULL(clk->parents[i]))
			clk->parents[i] = clk_lookup(clk->parent_names[i]);

		if (!IS_ERR_OR_NULL(clk->parents[i]))
			if (clk->parents[i] == parent)
				break;
	}

	if (i == clk->num_parents)
		return -EINVAL;

	return clk->ops->set_parent(clk, i);
}

struct clk *clk_get_parent(struct clk *clk)
{
	int idx;

	if (IS_ERR(clk))
		return clk;

	if (!clk->num_parents)
		return ERR_PTR(-ENODEV);

	if (clk->num_parents != 1) {
		if (!clk->ops->get_parent)
			return ERR_PTR(-EINVAL);

		idx = clk->ops->get_parent(clk);

		if (idx >= clk->num_parents)
			return ERR_PTR(-ENODEV);
	} else {
		idx = 0;
	}

	if (IS_ERR_OR_NULL(clk->parents[idx]))
		clk->parents[idx] = clk_lookup(clk->parent_names[idx]);

	return clk->parents[idx];
}

int clk_register(struct clk *clk)
{
	struct clk *c;

	list_for_each_entry(c, &clks, list) {
		if (!strcmp(c->name, clk->name)) {
			pr_err("%s clk %s is already registered, skipping!\n",
				__func__, clk->name);
			return -EBUSY;
		}
	}

	clk->parents = xzalloc(sizeof(struct clk *) * clk->num_parents);

	list_add_tail(&clk->list, &clks);

	return 0;
}

int clk_is_enabled(struct clk *clk)
{
	int enabled;

	if (IS_ERR(clk))
		return 0;

	if (clk->ops->is_enabled) {
		/*
		 * If we can ask a clk, do it
		 */
		enabled = clk->ops->is_enabled(clk);
	} else {
		if (clk->ops->enable) {
			/*
			 * If we can't ask a clk, but it can be enabled,
			 * depend on the enable_count.
			 */
			enabled = clk->enable_count;
		} else {
			/*
			 * We can't ask a clk, it has no enable op,
			 * so assume it's enabled and go on and ask
			 * the parent.
			 */
			enabled = 1;
		}
	}

	if (!enabled)
		return 0;

	clk = clk_get_parent(clk);

	if (IS_ERR(clk))
		return 1;

	return clk_is_enabled(clk);
}

/*
 * Generic struct clk_ops callbacks
 */
int clk_is_enabled_always(struct clk *clk)
{
	return 1;
}

long clk_parent_round_rate(struct clk *clk, unsigned long rate,
				unsigned long *prate)
{
	if (!(clk->flags & CLK_SET_RATE_PARENT))
		return *prate;

	return clk_round_rate(clk_get_parent(clk), rate);
}

int clk_parent_set_rate(struct clk *clk, unsigned long rate,
				unsigned long parent_rate)
{
	if (!(clk->flags & CLK_SET_RATE_PARENT))
		return 0;
	return clk_set_rate(clk_get_parent(clk), rate);
}

#if defined(CONFIG_OFTREE) && defined(CONFIG_COMMON_CLK_OF_PROVIDER)
/**
 * struct of_clk_provider - Clock provider registration structure
 * @link: Entry in global list of clock providers
 * @node: Pointer to device tree node of clock provider
 * @get: Get clock callback.  Returns NULL or a struct clk for the
 *       given clock specifier
 * @data: context pointer to be passed into @get callback
 */
struct of_clk_provider {
	struct list_head link;

	struct device_node *node;
	struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
	void *data;
};

extern struct of_device_id __clk_of_table_start[];
const struct of_device_id __clk_of_table_sentinel
	__attribute__ ((unused,section (".__clk_of_table_end")));

static LIST_HEAD(of_clk_providers);

struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
		void *data)
{
	return data;
}
EXPORT_SYMBOL_GPL(of_clk_src_simple_get);

struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
{
	struct clk_onecell_data *clk_data = data;
	unsigned int idx = clkspec->args[0];

	if (idx >= clk_data->clk_num) {
		pr_err("%s: invalid clock index %d\n", __func__, idx);
		return ERR_PTR(-EINVAL);
	}

	return clk_data->clks[idx];
}
EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);

/**
 * of_clk_add_provider() - Register a clock provider for a node
 * @np: Device node pointer associated with clock provider
 * @clk_src_get: callback for decoding clock
 * @data: context pointer for @clk_src_get callback.
 */
int of_clk_add_provider(struct device_node *np,
			struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
						   void *data),
			void *data)
{
	struct of_clk_provider *cp;

	cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
	if (!cp)
		return -ENOMEM;

	cp->node = np;
	cp->data = data;
	cp->get = clk_src_get;

	list_add(&cp->link, &of_clk_providers);
	pr_debug("Added clock from %s\n", np->full_name);

	return 0;
}
EXPORT_SYMBOL_GPL(of_clk_add_provider);

/**
 * of_clk_del_provider() - Remove a previously registered clock provider
 * @np: Device node pointer associated with clock provider
 */
void of_clk_del_provider(struct device_node *np)
{
	struct of_clk_provider *cp;

	list_for_each_entry(cp, &of_clk_providers, link) {
		if (cp->node == np) {
			list_del(&cp->link);
			kfree(cp);
			break;
		}
	}
}
EXPORT_SYMBOL_GPL(of_clk_del_provider);

struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
{
	struct of_clk_provider *provider;
	struct clk *clk = ERR_PTR(-EPROBE_DEFER);

	/* Check if we have such a provider in our array */
	list_for_each_entry(provider, &of_clk_providers, link) {
		if (provider->node == clkspec->np)
			clk = provider->get(clkspec, provider->data);
		if (!IS_ERR(clk))
			break;
	}

	return clk;
}

char *of_clk_get_parent_name(struct device_node *np, unsigned int index)
{
	struct of_phandle_args clkspec;
	const char *clk_name;
	int rc;

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

	if (of_property_read_string_index(clkspec.np, "clock-output-names",
				clkspec.args_count ? clkspec.args[0] : 0,
				&clk_name) < 0)
		clk_name = clkspec.np->name;

	return xstrdup(clk_name);
}
EXPORT_SYMBOL_GPL(of_clk_get_parent_name);

struct clock_provider {
	of_clk_init_cb_t clk_init_cb;
	struct device_node *np;
	struct list_head node;
};

/*
 * This function looks for a parent clock. If there is one, then it
 * checks that the provider for this parent clock was initialized, in
 * this case the parent clock will be ready.
 */
static int parent_ready(struct device_node *np)
{
	int i = 0;

	while (true) {
		struct clk *clk = of_clk_get(np, i);

		/* this parent is ready we can check the next one */
		if (!IS_ERR(clk)) {
			clk_put(clk);
			i++;
			continue;
		}

		/* at least one parent is not ready, we exit now */
		if (PTR_ERR(clk) == -EPROBE_DEFER)
			return 0;

		/*
		 * Here we make assumption that the device tree is
		 * written correctly. So an error means that there is
		 * no more parent. As we didn't exit yet, then the
		 * previous parent are ready. If there is no clock
		 * parent, no need to wait for them, then we can
		 * consider their absence as being ready
		 */
		return 1;
	}
}

/**
 * of_clk_init() - Scan and init clock providers from the DT
 * @root: parent of the first level to probe or NULL for the root of the tree
 * @matches: array of compatible values and init functions for providers.
 *
 * This function scans the device tree for matching clock providers and
 * calls their initialization functions
 *
 * Returns 0 on success, < 0 on failure.
 */
int of_clk_init(struct device_node *root, const struct of_device_id *matches)
{
	struct clock_provider *clk_provider, *next;
	bool is_init_done;
	bool force = false;
	LIST_HEAD(clk_provider_list);
	const struct of_device_id *match;

	if (!root)
		root = of_find_node_by_path("/");
	if (!root)
		return -EINVAL;
	if (!matches)
		matches = __clk_of_table_start;

	/* First prepare the list of the clocks providers */
	for_each_matching_node_and_match(root, matches, &match) {
		struct clock_provider *parent;

		if (!of_device_is_available(root))
			continue;

		parent = xzalloc(sizeof(*parent));

		parent->clk_init_cb = match->data;
		parent->np = root;
		list_add_tail(&parent->node, &clk_provider_list);
	}

	while (!list_empty(&clk_provider_list)) {
		is_init_done = false;
		list_for_each_entry_safe(clk_provider, next,
					 &clk_provider_list, node) {

			if (force || parent_ready(clk_provider->np)) {

				clk_provider->clk_init_cb(clk_provider->np);

				list_del(&clk_provider->node);
				free(clk_provider);
				is_init_done = true;
			}
		}

		/*
		 * We didn't manage to initialize any of the
		 * remaining providers during the last loop, so now we
		 * initialize all the remaining ones unconditionally
		 * in case the clock parent was not mandatory
		 */
		if (!is_init_done)
			force = true;
	}

	return 0;
}
#endif

static void dump_one(struct clk *clk, int verbose, int indent)
{
	struct clk *c;

	printf("%*s%s (rate %lu, %sabled)\n", indent * 4, "", clk->name, clk_get_rate(clk),
			clk_is_enabled(clk) ? "en" : "dis");
	if (verbose) {

		if (clk->num_parents > 1) {
			int i;
			printf("%*s`---- possible parents: ", indent * 4, "");
			for (i = 0; i < clk->num_parents; i++)
				printf("%s ", clk->parent_names[i]);
			printf("\n");
		}
	}

	list_for_each_entry(c, &clks, list) {
		struct clk *parent = clk_get_parent(c);

		if (parent == clk) {
			dump_one(c, verbose, indent + 1);
		}
	}
}

void clk_dump(int verbose)
{
	struct clk *c;

	list_for_each_entry(c, &clks, list) {
		struct clk *parent = clk_get_parent(c);

		if (IS_ERR_OR_NULL(parent))
			dump_one(c, verbose, 0);
	}
}

int clk_name_complete(struct string_list *sl, char *instr)
{
	struct clk *c;
	int len;

	if (!instr)
		instr = "";

	len = strlen(instr);

	list_for_each_entry(c, &clks, list) {
		if (strncmp(instr, c->name, len))
			continue;

		string_list_add_asprintf(sl, "%s ", c->name);
	}

	return COMPLETE_CONTINUE;
}