xref: /openbmc/linux/drivers/clk/at91/clk-main.c (revision 275876e2)
1 /*
2  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  */
10 
11 #include <linux/clk-provider.h>
12 #include <linux/clkdev.h>
13 #include <linux/clk/at91_pmc.h>
14 #include <linux/delay.h>
15 #include <linux/of.h>
16 #include <linux/of_address.h>
17 #include <linux/of_irq.h>
18 #include <linux/io.h>
19 #include <linux/interrupt.h>
20 #include <linux/irq.h>
21 #include <linux/sched.h>
22 #include <linux/wait.h>
23 
24 #include "pmc.h"
25 
26 #define SLOW_CLOCK_FREQ		32768
27 #define MAINF_DIV		16
28 #define MAINFRDY_TIMEOUT	(((MAINF_DIV + 1) * USEC_PER_SEC) / \
29 				 SLOW_CLOCK_FREQ)
30 #define MAINF_LOOP_MIN_WAIT	(USEC_PER_SEC / SLOW_CLOCK_FREQ)
31 #define MAINF_LOOP_MAX_WAIT	MAINFRDY_TIMEOUT
32 
33 #define MOR_KEY_MASK		(0xff << 16)
34 
35 struct clk_main_osc {
36 	struct clk_hw hw;
37 	struct at91_pmc *pmc;
38 	unsigned int irq;
39 	wait_queue_head_t wait;
40 };
41 
42 #define to_clk_main_osc(hw) container_of(hw, struct clk_main_osc, hw)
43 
44 struct clk_main_rc_osc {
45 	struct clk_hw hw;
46 	struct at91_pmc *pmc;
47 	unsigned int irq;
48 	wait_queue_head_t wait;
49 	unsigned long frequency;
50 	unsigned long accuracy;
51 };
52 
53 #define to_clk_main_rc_osc(hw) container_of(hw, struct clk_main_rc_osc, hw)
54 
55 struct clk_rm9200_main {
56 	struct clk_hw hw;
57 	struct at91_pmc *pmc;
58 };
59 
60 #define to_clk_rm9200_main(hw) container_of(hw, struct clk_rm9200_main, hw)
61 
62 struct clk_sam9x5_main {
63 	struct clk_hw hw;
64 	struct at91_pmc *pmc;
65 	unsigned int irq;
66 	wait_queue_head_t wait;
67 	u8 parent;
68 };
69 
70 #define to_clk_sam9x5_main(hw) container_of(hw, struct clk_sam9x5_main, hw)
71 
72 static irqreturn_t clk_main_osc_irq_handler(int irq, void *dev_id)
73 {
74 	struct clk_main_osc *osc = dev_id;
75 
76 	wake_up(&osc->wait);
77 	disable_irq_nosync(osc->irq);
78 
79 	return IRQ_HANDLED;
80 }
81 
82 static int clk_main_osc_prepare(struct clk_hw *hw)
83 {
84 	struct clk_main_osc *osc = to_clk_main_osc(hw);
85 	struct at91_pmc *pmc = osc->pmc;
86 	u32 tmp;
87 
88 	tmp = pmc_read(pmc, AT91_CKGR_MOR) & ~MOR_KEY_MASK;
89 	if (tmp & AT91_PMC_OSCBYPASS)
90 		return 0;
91 
92 	if (!(tmp & AT91_PMC_MOSCEN)) {
93 		tmp |= AT91_PMC_MOSCEN | AT91_PMC_KEY;
94 		pmc_write(pmc, AT91_CKGR_MOR, tmp);
95 	}
96 
97 	while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS)) {
98 		enable_irq(osc->irq);
99 		wait_event(osc->wait,
100 			   pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS);
101 	}
102 
103 	return 0;
104 }
105 
106 static void clk_main_osc_unprepare(struct clk_hw *hw)
107 {
108 	struct clk_main_osc *osc = to_clk_main_osc(hw);
109 	struct at91_pmc *pmc = osc->pmc;
110 	u32 tmp = pmc_read(pmc, AT91_CKGR_MOR);
111 
112 	if (tmp & AT91_PMC_OSCBYPASS)
113 		return;
114 
115 	if (!(tmp & AT91_PMC_MOSCEN))
116 		return;
117 
118 	tmp &= ~(AT91_PMC_KEY | AT91_PMC_MOSCEN);
119 	pmc_write(pmc, AT91_CKGR_MOR, tmp | AT91_PMC_KEY);
120 }
121 
122 static int clk_main_osc_is_prepared(struct clk_hw *hw)
123 {
124 	struct clk_main_osc *osc = to_clk_main_osc(hw);
125 	struct at91_pmc *pmc = osc->pmc;
126 	u32 tmp = pmc_read(pmc, AT91_CKGR_MOR);
127 
128 	if (tmp & AT91_PMC_OSCBYPASS)
129 		return 1;
130 
131 	return !!((pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS) &&
132 		  (pmc_read(pmc, AT91_CKGR_MOR) & AT91_PMC_MOSCEN));
133 }
134 
135 static const struct clk_ops main_osc_ops = {
136 	.prepare = clk_main_osc_prepare,
137 	.unprepare = clk_main_osc_unprepare,
138 	.is_prepared = clk_main_osc_is_prepared,
139 };
140 
141 static struct clk * __init
142 at91_clk_register_main_osc(struct at91_pmc *pmc,
143 			   unsigned int irq,
144 			   const char *name,
145 			   const char *parent_name,
146 			   bool bypass)
147 {
148 	int ret;
149 	struct clk_main_osc *osc;
150 	struct clk *clk = NULL;
151 	struct clk_init_data init;
152 
153 	if (!pmc || !irq || !name || !parent_name)
154 		return ERR_PTR(-EINVAL);
155 
156 	osc = kzalloc(sizeof(*osc), GFP_KERNEL);
157 	if (!osc)
158 		return ERR_PTR(-ENOMEM);
159 
160 	init.name = name;
161 	init.ops = &main_osc_ops;
162 	init.parent_names = &parent_name;
163 	init.num_parents = 1;
164 	init.flags = CLK_IGNORE_UNUSED;
165 
166 	osc->hw.init = &init;
167 	osc->pmc = pmc;
168 	osc->irq = irq;
169 
170 	init_waitqueue_head(&osc->wait);
171 	irq_set_status_flags(osc->irq, IRQ_NOAUTOEN);
172 	ret = request_irq(osc->irq, clk_main_osc_irq_handler,
173 			  IRQF_TRIGGER_HIGH, name, osc);
174 	if (ret)
175 		return ERR_PTR(ret);
176 
177 	if (bypass)
178 		pmc_write(pmc, AT91_CKGR_MOR,
179 			  (pmc_read(pmc, AT91_CKGR_MOR) &
180 			   ~(MOR_KEY_MASK | AT91_PMC_MOSCEN)) |
181 			  AT91_PMC_OSCBYPASS | AT91_PMC_KEY);
182 
183 	clk = clk_register(NULL, &osc->hw);
184 	if (IS_ERR(clk)) {
185 		free_irq(irq, osc);
186 		kfree(osc);
187 	}
188 
189 	return clk;
190 }
191 
192 void __init of_at91rm9200_clk_main_osc_setup(struct device_node *np,
193 					     struct at91_pmc *pmc)
194 {
195 	struct clk *clk;
196 	unsigned int irq;
197 	const char *name = np->name;
198 	const char *parent_name;
199 	bool bypass;
200 
201 	of_property_read_string(np, "clock-output-names", &name);
202 	bypass = of_property_read_bool(np, "atmel,osc-bypass");
203 	parent_name = of_clk_get_parent_name(np, 0);
204 
205 	irq = irq_of_parse_and_map(np, 0);
206 	if (!irq)
207 		return;
208 
209 	clk = at91_clk_register_main_osc(pmc, irq, name, parent_name, bypass);
210 	if (IS_ERR(clk))
211 		return;
212 
213 	of_clk_add_provider(np, of_clk_src_simple_get, clk);
214 }
215 
216 static irqreturn_t clk_main_rc_osc_irq_handler(int irq, void *dev_id)
217 {
218 	struct clk_main_rc_osc *osc = dev_id;
219 
220 	wake_up(&osc->wait);
221 	disable_irq_nosync(osc->irq);
222 
223 	return IRQ_HANDLED;
224 }
225 
226 static int clk_main_rc_osc_prepare(struct clk_hw *hw)
227 {
228 	struct clk_main_rc_osc *osc = to_clk_main_rc_osc(hw);
229 	struct at91_pmc *pmc = osc->pmc;
230 	u32 tmp;
231 
232 	tmp = pmc_read(pmc, AT91_CKGR_MOR) & ~MOR_KEY_MASK;
233 
234 	if (!(tmp & AT91_PMC_MOSCRCEN)) {
235 		tmp |= AT91_PMC_MOSCRCEN | AT91_PMC_KEY;
236 		pmc_write(pmc, AT91_CKGR_MOR, tmp);
237 	}
238 
239 	while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCRCS)) {
240 		enable_irq(osc->irq);
241 		wait_event(osc->wait,
242 			   pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCRCS);
243 	}
244 
245 	return 0;
246 }
247 
248 static void clk_main_rc_osc_unprepare(struct clk_hw *hw)
249 {
250 	struct clk_main_rc_osc *osc = to_clk_main_rc_osc(hw);
251 	struct at91_pmc *pmc = osc->pmc;
252 	u32 tmp = pmc_read(pmc, AT91_CKGR_MOR);
253 
254 	if (!(tmp & AT91_PMC_MOSCRCEN))
255 		return;
256 
257 	tmp &= ~(MOR_KEY_MASK | AT91_PMC_MOSCRCEN);
258 	pmc_write(pmc, AT91_CKGR_MOR, tmp | AT91_PMC_KEY);
259 }
260 
261 static int clk_main_rc_osc_is_prepared(struct clk_hw *hw)
262 {
263 	struct clk_main_rc_osc *osc = to_clk_main_rc_osc(hw);
264 	struct at91_pmc *pmc = osc->pmc;
265 
266 	return !!((pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCRCS) &&
267 		  (pmc_read(pmc, AT91_CKGR_MOR) & AT91_PMC_MOSCRCEN));
268 }
269 
270 static unsigned long clk_main_rc_osc_recalc_rate(struct clk_hw *hw,
271 						 unsigned long parent_rate)
272 {
273 	struct clk_main_rc_osc *osc = to_clk_main_rc_osc(hw);
274 
275 	return osc->frequency;
276 }
277 
278 static unsigned long clk_main_rc_osc_recalc_accuracy(struct clk_hw *hw,
279 						     unsigned long parent_acc)
280 {
281 	struct clk_main_rc_osc *osc = to_clk_main_rc_osc(hw);
282 
283 	return osc->accuracy;
284 }
285 
286 static const struct clk_ops main_rc_osc_ops = {
287 	.prepare = clk_main_rc_osc_prepare,
288 	.unprepare = clk_main_rc_osc_unprepare,
289 	.is_prepared = clk_main_rc_osc_is_prepared,
290 	.recalc_rate = clk_main_rc_osc_recalc_rate,
291 	.recalc_accuracy = clk_main_rc_osc_recalc_accuracy,
292 };
293 
294 static struct clk * __init
295 at91_clk_register_main_rc_osc(struct at91_pmc *pmc,
296 			      unsigned int irq,
297 			      const char *name,
298 			      u32 frequency, u32 accuracy)
299 {
300 	int ret;
301 	struct clk_main_rc_osc *osc;
302 	struct clk *clk = NULL;
303 	struct clk_init_data init;
304 
305 	if (!pmc || !irq || !name || !frequency)
306 		return ERR_PTR(-EINVAL);
307 
308 	osc = kzalloc(sizeof(*osc), GFP_KERNEL);
309 	if (!osc)
310 		return ERR_PTR(-ENOMEM);
311 
312 	init.name = name;
313 	init.ops = &main_rc_osc_ops;
314 	init.parent_names = NULL;
315 	init.num_parents = 0;
316 	init.flags = CLK_IS_ROOT | CLK_IGNORE_UNUSED;
317 
318 	osc->hw.init = &init;
319 	osc->pmc = pmc;
320 	osc->irq = irq;
321 	osc->frequency = frequency;
322 	osc->accuracy = accuracy;
323 
324 	init_waitqueue_head(&osc->wait);
325 	irq_set_status_flags(osc->irq, IRQ_NOAUTOEN);
326 	ret = request_irq(osc->irq, clk_main_rc_osc_irq_handler,
327 			  IRQF_TRIGGER_HIGH, name, osc);
328 	if (ret)
329 		return ERR_PTR(ret);
330 
331 	clk = clk_register(NULL, &osc->hw);
332 	if (IS_ERR(clk)) {
333 		free_irq(irq, osc);
334 		kfree(osc);
335 	}
336 
337 	return clk;
338 }
339 
340 void __init of_at91sam9x5_clk_main_rc_osc_setup(struct device_node *np,
341 						struct at91_pmc *pmc)
342 {
343 	struct clk *clk;
344 	unsigned int irq;
345 	u32 frequency = 0;
346 	u32 accuracy = 0;
347 	const char *name = np->name;
348 
349 	of_property_read_string(np, "clock-output-names", &name);
350 	of_property_read_u32(np, "clock-frequency", &frequency);
351 	of_property_read_u32(np, "clock-accuracy", &accuracy);
352 
353 	irq = irq_of_parse_and_map(np, 0);
354 	if (!irq)
355 		return;
356 
357 	clk = at91_clk_register_main_rc_osc(pmc, irq, name, frequency,
358 					    accuracy);
359 	if (IS_ERR(clk))
360 		return;
361 
362 	of_clk_add_provider(np, of_clk_src_simple_get, clk);
363 }
364 
365 
366 static int clk_main_probe_frequency(struct at91_pmc *pmc)
367 {
368 	unsigned long prep_time, timeout;
369 	u32 tmp;
370 
371 	timeout = jiffies + usecs_to_jiffies(MAINFRDY_TIMEOUT);
372 	do {
373 		prep_time = jiffies;
374 		tmp = pmc_read(pmc, AT91_CKGR_MCFR);
375 		if (tmp & AT91_PMC_MAINRDY)
376 			return 0;
377 		usleep_range(MAINF_LOOP_MIN_WAIT, MAINF_LOOP_MAX_WAIT);
378 	} while (time_before(prep_time, timeout));
379 
380 	return -ETIMEDOUT;
381 }
382 
383 static unsigned long clk_main_recalc_rate(struct at91_pmc *pmc,
384 					  unsigned long parent_rate)
385 {
386 	u32 tmp;
387 
388 	if (parent_rate)
389 		return parent_rate;
390 
391 	pr_warn("Main crystal frequency not set, using approximate value\n");
392 	tmp = pmc_read(pmc, AT91_CKGR_MCFR);
393 	if (!(tmp & AT91_PMC_MAINRDY))
394 		return 0;
395 
396 	return ((tmp & AT91_PMC_MAINF) * SLOW_CLOCK_FREQ) / MAINF_DIV;
397 }
398 
399 static int clk_rm9200_main_prepare(struct clk_hw *hw)
400 {
401 	struct clk_rm9200_main *clkmain = to_clk_rm9200_main(hw);
402 
403 	return clk_main_probe_frequency(clkmain->pmc);
404 }
405 
406 static int clk_rm9200_main_is_prepared(struct clk_hw *hw)
407 {
408 	struct clk_rm9200_main *clkmain = to_clk_rm9200_main(hw);
409 
410 	return !!(pmc_read(clkmain->pmc, AT91_CKGR_MCFR) & AT91_PMC_MAINRDY);
411 }
412 
413 static unsigned long clk_rm9200_main_recalc_rate(struct clk_hw *hw,
414 						 unsigned long parent_rate)
415 {
416 	struct clk_rm9200_main *clkmain = to_clk_rm9200_main(hw);
417 
418 	return clk_main_recalc_rate(clkmain->pmc, parent_rate);
419 }
420 
421 static const struct clk_ops rm9200_main_ops = {
422 	.prepare = clk_rm9200_main_prepare,
423 	.is_prepared = clk_rm9200_main_is_prepared,
424 	.recalc_rate = clk_rm9200_main_recalc_rate,
425 };
426 
427 static struct clk * __init
428 at91_clk_register_rm9200_main(struct at91_pmc *pmc,
429 			      const char *name,
430 			      const char *parent_name)
431 {
432 	struct clk_rm9200_main *clkmain;
433 	struct clk *clk = NULL;
434 	struct clk_init_data init;
435 
436 	if (!pmc || !name)
437 		return ERR_PTR(-EINVAL);
438 
439 	if (!parent_name)
440 		return ERR_PTR(-EINVAL);
441 
442 	clkmain = kzalloc(sizeof(*clkmain), GFP_KERNEL);
443 	if (!clkmain)
444 		return ERR_PTR(-ENOMEM);
445 
446 	init.name = name;
447 	init.ops = &rm9200_main_ops;
448 	init.parent_names = &parent_name;
449 	init.num_parents = 1;
450 	init.flags = 0;
451 
452 	clkmain->hw.init = &init;
453 	clkmain->pmc = pmc;
454 
455 	clk = clk_register(NULL, &clkmain->hw);
456 	if (IS_ERR(clk))
457 		kfree(clkmain);
458 
459 	return clk;
460 }
461 
462 void __init of_at91rm9200_clk_main_setup(struct device_node *np,
463 					 struct at91_pmc *pmc)
464 {
465 	struct clk *clk;
466 	const char *parent_name;
467 	const char *name = np->name;
468 
469 	parent_name = of_clk_get_parent_name(np, 0);
470 	of_property_read_string(np, "clock-output-names", &name);
471 
472 	clk = at91_clk_register_rm9200_main(pmc, name, parent_name);
473 	if (IS_ERR(clk))
474 		return;
475 
476 	of_clk_add_provider(np, of_clk_src_simple_get, clk);
477 }
478 
479 static irqreturn_t clk_sam9x5_main_irq_handler(int irq, void *dev_id)
480 {
481 	struct clk_sam9x5_main *clkmain = dev_id;
482 
483 	wake_up(&clkmain->wait);
484 	disable_irq_nosync(clkmain->irq);
485 
486 	return IRQ_HANDLED;
487 }
488 
489 static int clk_sam9x5_main_prepare(struct clk_hw *hw)
490 {
491 	struct clk_sam9x5_main *clkmain = to_clk_sam9x5_main(hw);
492 	struct at91_pmc *pmc = clkmain->pmc;
493 
494 	while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCSELS)) {
495 		enable_irq(clkmain->irq);
496 		wait_event(clkmain->wait,
497 			   pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCSELS);
498 	}
499 
500 	return clk_main_probe_frequency(pmc);
501 }
502 
503 static int clk_sam9x5_main_is_prepared(struct clk_hw *hw)
504 {
505 	struct clk_sam9x5_main *clkmain = to_clk_sam9x5_main(hw);
506 
507 	return !!(pmc_read(clkmain->pmc, AT91_PMC_SR) & AT91_PMC_MOSCSELS);
508 }
509 
510 static unsigned long clk_sam9x5_main_recalc_rate(struct clk_hw *hw,
511 						 unsigned long parent_rate)
512 {
513 	struct clk_sam9x5_main *clkmain = to_clk_sam9x5_main(hw);
514 
515 	return clk_main_recalc_rate(clkmain->pmc, parent_rate);
516 }
517 
518 static int clk_sam9x5_main_set_parent(struct clk_hw *hw, u8 index)
519 {
520 	struct clk_sam9x5_main *clkmain = to_clk_sam9x5_main(hw);
521 	struct at91_pmc *pmc = clkmain->pmc;
522 	u32 tmp;
523 
524 	if (index > 1)
525 		return -EINVAL;
526 
527 	tmp = pmc_read(pmc, AT91_CKGR_MOR) & ~MOR_KEY_MASK;
528 
529 	if (index && !(tmp & AT91_PMC_MOSCSEL))
530 		pmc_write(pmc, AT91_CKGR_MOR, tmp | AT91_PMC_MOSCSEL);
531 	else if (!index && (tmp & AT91_PMC_MOSCSEL))
532 		pmc_write(pmc, AT91_CKGR_MOR, tmp & ~AT91_PMC_MOSCSEL);
533 
534 	while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCSELS)) {
535 		enable_irq(clkmain->irq);
536 		wait_event(clkmain->wait,
537 			   pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCSELS);
538 	}
539 
540 	return 0;
541 }
542 
543 static u8 clk_sam9x5_main_get_parent(struct clk_hw *hw)
544 {
545 	struct clk_sam9x5_main *clkmain = to_clk_sam9x5_main(hw);
546 
547 	return !!(pmc_read(clkmain->pmc, AT91_CKGR_MOR) & AT91_PMC_MOSCEN);
548 }
549 
550 static const struct clk_ops sam9x5_main_ops = {
551 	.prepare = clk_sam9x5_main_prepare,
552 	.is_prepared = clk_sam9x5_main_is_prepared,
553 	.recalc_rate = clk_sam9x5_main_recalc_rate,
554 	.set_parent = clk_sam9x5_main_set_parent,
555 	.get_parent = clk_sam9x5_main_get_parent,
556 };
557 
558 static struct clk * __init
559 at91_clk_register_sam9x5_main(struct at91_pmc *pmc,
560 			      unsigned int irq,
561 			      const char *name,
562 			      const char **parent_names,
563 			      int num_parents)
564 {
565 	int ret;
566 	struct clk_sam9x5_main *clkmain;
567 	struct clk *clk = NULL;
568 	struct clk_init_data init;
569 
570 	if (!pmc || !irq || !name)
571 		return ERR_PTR(-EINVAL);
572 
573 	if (!parent_names || !num_parents)
574 		return ERR_PTR(-EINVAL);
575 
576 	clkmain = kzalloc(sizeof(*clkmain), GFP_KERNEL);
577 	if (!clkmain)
578 		return ERR_PTR(-ENOMEM);
579 
580 	init.name = name;
581 	init.ops = &sam9x5_main_ops;
582 	init.parent_names = parent_names;
583 	init.num_parents = num_parents;
584 	init.flags = CLK_SET_PARENT_GATE;
585 
586 	clkmain->hw.init = &init;
587 	clkmain->pmc = pmc;
588 	clkmain->irq = irq;
589 	clkmain->parent = !!(pmc_read(clkmain->pmc, AT91_CKGR_MOR) &
590 			     AT91_PMC_MOSCEN);
591 	init_waitqueue_head(&clkmain->wait);
592 	irq_set_status_flags(clkmain->irq, IRQ_NOAUTOEN);
593 	ret = request_irq(clkmain->irq, clk_sam9x5_main_irq_handler,
594 			  IRQF_TRIGGER_HIGH, name, clkmain);
595 	if (ret)
596 		return ERR_PTR(ret);
597 
598 	clk = clk_register(NULL, &clkmain->hw);
599 	if (IS_ERR(clk)) {
600 		free_irq(clkmain->irq, clkmain);
601 		kfree(clkmain);
602 	}
603 
604 	return clk;
605 }
606 
607 void __init of_at91sam9x5_clk_main_setup(struct device_node *np,
608 					 struct at91_pmc *pmc)
609 {
610 	struct clk *clk;
611 	const char *parent_names[2];
612 	int num_parents;
613 	unsigned int irq;
614 	const char *name = np->name;
615 	int i;
616 
617 	num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
618 	if (num_parents <= 0 || num_parents > 2)
619 		return;
620 
621 	for (i = 0; i < num_parents; ++i) {
622 		parent_names[i] = of_clk_get_parent_name(np, i);
623 		if (!parent_names[i])
624 			return;
625 	}
626 
627 	of_property_read_string(np, "clock-output-names", &name);
628 
629 	irq = irq_of_parse_and_map(np, 0);
630 	if (!irq)
631 		return;
632 
633 	clk = at91_clk_register_sam9x5_main(pmc, irq, name, parent_names,
634 					    num_parents);
635 	if (IS_ERR(clk))
636 		return;
637 
638 	of_clk_add_provider(np, of_clk_src_simple_get, clk);
639 }
640