xref: /openbmc/linux/drivers/clk/ingenic/cgu.c (revision 8dde5715)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Ingenic SoC CGU driver
4  *
5  * Copyright (c) 2013-2015 Imagination Technologies
6  * Author: Paul Burton <paul.burton@mips.com>
7  */
8 
9 #include <linux/bitops.h>
10 #include <linux/clk.h>
11 #include <linux/clk-provider.h>
12 #include <linux/clkdev.h>
13 #include <linux/delay.h>
14 #include <linux/io.h>
15 #include <linux/math64.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/slab.h>
19 #include <linux/spinlock.h>
20 #include "cgu.h"
21 
22 #define MHZ (1000 * 1000)
23 
24 /**
25  * ingenic_cgu_gate_get() - get the value of clock gate register bit
26  * @cgu: reference to the CGU whose registers should be read
27  * @info: info struct describing the gate bit
28  *
29  * Retrieves the state of the clock gate bit described by info. The
30  * caller must hold cgu->lock.
31  *
32  * Return: true if the gate bit is set, else false.
33  */
34 static inline bool
35 ingenic_cgu_gate_get(struct ingenic_cgu *cgu,
36 		     const struct ingenic_cgu_gate_info *info)
37 {
38 	return !!(readl(cgu->base + info->reg) & BIT(info->bit))
39 		^ info->clear_to_gate;
40 }
41 
42 /**
43  * ingenic_cgu_gate_set() - set the value of clock gate register bit
44  * @cgu: reference to the CGU whose registers should be modified
45  * @info: info struct describing the gate bit
46  * @val: non-zero to gate a clock, otherwise zero
47  *
48  * Sets the given gate bit in order to gate or ungate a clock.
49  *
50  * The caller must hold cgu->lock.
51  */
52 static inline void
53 ingenic_cgu_gate_set(struct ingenic_cgu *cgu,
54 		     const struct ingenic_cgu_gate_info *info, bool val)
55 {
56 	u32 clkgr = readl(cgu->base + info->reg);
57 
58 	if (val ^ info->clear_to_gate)
59 		clkgr |= BIT(info->bit);
60 	else
61 		clkgr &= ~BIT(info->bit);
62 
63 	writel(clkgr, cgu->base + info->reg);
64 }
65 
66 /*
67  * PLL operations
68  */
69 
70 static unsigned long
71 ingenic_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
72 {
73 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
74 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
75 	const struct ingenic_cgu_clk_info *clk_info;
76 	const struct ingenic_cgu_pll_info *pll_info;
77 	unsigned m, n, od_enc, od;
78 	bool bypass;
79 	unsigned long flags;
80 	u32 ctl;
81 
82 	clk_info = &cgu->clock_info[ingenic_clk->idx];
83 	BUG_ON(clk_info->type != CGU_CLK_PLL);
84 	pll_info = &clk_info->pll;
85 
86 	spin_lock_irqsave(&cgu->lock, flags);
87 	ctl = readl(cgu->base + pll_info->reg);
88 	spin_unlock_irqrestore(&cgu->lock, flags);
89 
90 	m = (ctl >> pll_info->m_shift) & GENMASK(pll_info->m_bits - 1, 0);
91 	m += pll_info->m_offset;
92 	n = (ctl >> pll_info->n_shift) & GENMASK(pll_info->n_bits - 1, 0);
93 	n += pll_info->n_offset;
94 	od_enc = ctl >> pll_info->od_shift;
95 	od_enc &= GENMASK(pll_info->od_bits - 1, 0);
96 	bypass = !pll_info->no_bypass_bit &&
97 		 !!(ctl & BIT(pll_info->bypass_bit));
98 
99 	if (bypass)
100 		return parent_rate;
101 
102 	for (od = 0; od < pll_info->od_max; od++) {
103 		if (pll_info->od_encoding[od] == od_enc)
104 			break;
105 	}
106 	BUG_ON(od == pll_info->od_max);
107 	od++;
108 
109 	return div_u64((u64)parent_rate * m, n * od);
110 }
111 
112 static unsigned long
113 ingenic_pll_calc(const struct ingenic_cgu_clk_info *clk_info,
114 		 unsigned long rate, unsigned long parent_rate,
115 		 unsigned *pm, unsigned *pn, unsigned *pod)
116 {
117 	const struct ingenic_cgu_pll_info *pll_info;
118 	unsigned m, n, od;
119 
120 	pll_info = &clk_info->pll;
121 	od = 1;
122 
123 	/*
124 	 * The frequency after the input divider must be between 10 and 50 MHz.
125 	 * The highest divider yields the best resolution.
126 	 */
127 	n = parent_rate / (10 * MHZ);
128 	n = min_t(unsigned, n, 1 << clk_info->pll.n_bits);
129 	n = max_t(unsigned, n, pll_info->n_offset);
130 
131 	m = (rate / MHZ) * od * n / (parent_rate / MHZ);
132 	m = min_t(unsigned, m, 1 << clk_info->pll.m_bits);
133 	m = max_t(unsigned, m, pll_info->m_offset);
134 
135 	if (pm)
136 		*pm = m;
137 	if (pn)
138 		*pn = n;
139 	if (pod)
140 		*pod = od;
141 
142 	return div_u64((u64)parent_rate * m, n * od);
143 }
144 
145 static inline const struct ingenic_cgu_clk_info *to_clk_info(
146 		struct ingenic_clk *ingenic_clk)
147 {
148 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
149 	const struct ingenic_cgu_clk_info *clk_info;
150 
151 	clk_info = &cgu->clock_info[ingenic_clk->idx];
152 	BUG_ON(clk_info->type != CGU_CLK_PLL);
153 
154 	return clk_info;
155 }
156 
157 static long
158 ingenic_pll_round_rate(struct clk_hw *hw, unsigned long req_rate,
159 		       unsigned long *prate)
160 {
161 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
162 	const struct ingenic_cgu_clk_info *clk_info = to_clk_info(ingenic_clk);
163 
164 	return ingenic_pll_calc(clk_info, req_rate, *prate, NULL, NULL, NULL);
165 }
166 
167 static int
168 ingenic_pll_set_rate(struct clk_hw *hw, unsigned long req_rate,
169 		     unsigned long parent_rate)
170 {
171 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
172 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
173 	const struct ingenic_cgu_clk_info *clk_info = to_clk_info(ingenic_clk);
174 	const struct ingenic_cgu_pll_info *pll_info = &clk_info->pll;
175 	unsigned long rate, flags;
176 	unsigned int m, n, od;
177 	u32 ctl;
178 
179 	rate = ingenic_pll_calc(clk_info, req_rate, parent_rate,
180 			       &m, &n, &od);
181 	if (rate != req_rate)
182 		pr_info("ingenic-cgu: request '%s' rate %luHz, actual %luHz\n",
183 			clk_info->name, req_rate, rate);
184 
185 	spin_lock_irqsave(&cgu->lock, flags);
186 	ctl = readl(cgu->base + pll_info->reg);
187 
188 	ctl &= ~(GENMASK(pll_info->m_bits - 1, 0) << pll_info->m_shift);
189 	ctl |= (m - pll_info->m_offset) << pll_info->m_shift;
190 
191 	ctl &= ~(GENMASK(pll_info->n_bits - 1, 0) << pll_info->n_shift);
192 	ctl |= (n - pll_info->n_offset) << pll_info->n_shift;
193 
194 	ctl &= ~(GENMASK(pll_info->od_bits - 1, 0) << pll_info->od_shift);
195 	ctl |= pll_info->od_encoding[od - 1] << pll_info->od_shift;
196 
197 	writel(ctl, cgu->base + pll_info->reg);
198 	spin_unlock_irqrestore(&cgu->lock, flags);
199 
200 	return 0;
201 }
202 
203 static int ingenic_pll_enable(struct clk_hw *hw)
204 {
205 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
206 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
207 	const struct ingenic_cgu_clk_info *clk_info = to_clk_info(ingenic_clk);
208 	const struct ingenic_cgu_pll_info *pll_info = &clk_info->pll;
209 	const unsigned int timeout = 100;
210 	unsigned long flags;
211 	unsigned int i;
212 	u32 ctl;
213 
214 	spin_lock_irqsave(&cgu->lock, flags);
215 	ctl = readl(cgu->base + pll_info->reg);
216 
217 	ctl &= ~BIT(pll_info->bypass_bit);
218 	ctl |= BIT(pll_info->enable_bit);
219 
220 	writel(ctl, cgu->base + pll_info->reg);
221 
222 	/* wait for the PLL to stabilise */
223 	for (i = 0; i < timeout; i++) {
224 		ctl = readl(cgu->base + pll_info->reg);
225 		if (ctl & BIT(pll_info->stable_bit))
226 			break;
227 		mdelay(1);
228 	}
229 
230 	spin_unlock_irqrestore(&cgu->lock, flags);
231 
232 	if (i == timeout)
233 		return -EBUSY;
234 
235 	return 0;
236 }
237 
238 static void ingenic_pll_disable(struct clk_hw *hw)
239 {
240 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
241 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
242 	const struct ingenic_cgu_clk_info *clk_info = to_clk_info(ingenic_clk);
243 	const struct ingenic_cgu_pll_info *pll_info = &clk_info->pll;
244 	unsigned long flags;
245 	u32 ctl;
246 
247 	spin_lock_irqsave(&cgu->lock, flags);
248 	ctl = readl(cgu->base + pll_info->reg);
249 
250 	ctl &= ~BIT(pll_info->enable_bit);
251 
252 	writel(ctl, cgu->base + pll_info->reg);
253 	spin_unlock_irqrestore(&cgu->lock, flags);
254 }
255 
256 static int ingenic_pll_is_enabled(struct clk_hw *hw)
257 {
258 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
259 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
260 	const struct ingenic_cgu_clk_info *clk_info = to_clk_info(ingenic_clk);
261 	const struct ingenic_cgu_pll_info *pll_info = &clk_info->pll;
262 	unsigned long flags;
263 	u32 ctl;
264 
265 	spin_lock_irqsave(&cgu->lock, flags);
266 	ctl = readl(cgu->base + pll_info->reg);
267 	spin_unlock_irqrestore(&cgu->lock, flags);
268 
269 	return !!(ctl & BIT(pll_info->enable_bit));
270 }
271 
272 static const struct clk_ops ingenic_pll_ops = {
273 	.recalc_rate = ingenic_pll_recalc_rate,
274 	.round_rate = ingenic_pll_round_rate,
275 	.set_rate = ingenic_pll_set_rate,
276 
277 	.enable = ingenic_pll_enable,
278 	.disable = ingenic_pll_disable,
279 	.is_enabled = ingenic_pll_is_enabled,
280 };
281 
282 /*
283  * Operations for all non-PLL clocks
284  */
285 
286 static u8 ingenic_clk_get_parent(struct clk_hw *hw)
287 {
288 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
289 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
290 	const struct ingenic_cgu_clk_info *clk_info;
291 	u32 reg;
292 	u8 i, hw_idx, idx = 0;
293 
294 	clk_info = &cgu->clock_info[ingenic_clk->idx];
295 
296 	if (clk_info->type & CGU_CLK_MUX) {
297 		reg = readl(cgu->base + clk_info->mux.reg);
298 		hw_idx = (reg >> clk_info->mux.shift) &
299 			 GENMASK(clk_info->mux.bits - 1, 0);
300 
301 		/*
302 		 * Convert the hardware index to the parent index by skipping
303 		 * over any -1's in the parents array.
304 		 */
305 		for (i = 0; i < hw_idx; i++) {
306 			if (clk_info->parents[i] != -1)
307 				idx++;
308 		}
309 	}
310 
311 	return idx;
312 }
313 
314 static int ingenic_clk_set_parent(struct clk_hw *hw, u8 idx)
315 {
316 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
317 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
318 	const struct ingenic_cgu_clk_info *clk_info;
319 	unsigned long flags;
320 	u8 curr_idx, hw_idx, num_poss;
321 	u32 reg, mask;
322 
323 	clk_info = &cgu->clock_info[ingenic_clk->idx];
324 
325 	if (clk_info->type & CGU_CLK_MUX) {
326 		/*
327 		 * Convert the parent index to the hardware index by adding
328 		 * 1 for any -1 in the parents array preceding the given
329 		 * index. That is, we want the index of idx'th entry in
330 		 * clk_info->parents which does not equal -1.
331 		 */
332 		hw_idx = curr_idx = 0;
333 		num_poss = 1 << clk_info->mux.bits;
334 		for (; hw_idx < num_poss; hw_idx++) {
335 			if (clk_info->parents[hw_idx] == -1)
336 				continue;
337 			if (curr_idx == idx)
338 				break;
339 			curr_idx++;
340 		}
341 
342 		/* idx should always be a valid parent */
343 		BUG_ON(curr_idx != idx);
344 
345 		mask = GENMASK(clk_info->mux.bits - 1, 0);
346 		mask <<= clk_info->mux.shift;
347 
348 		spin_lock_irqsave(&cgu->lock, flags);
349 
350 		/* write the register */
351 		reg = readl(cgu->base + clk_info->mux.reg);
352 		reg &= ~mask;
353 		reg |= hw_idx << clk_info->mux.shift;
354 		writel(reg, cgu->base + clk_info->mux.reg);
355 
356 		spin_unlock_irqrestore(&cgu->lock, flags);
357 		return 0;
358 	}
359 
360 	return idx ? -EINVAL : 0;
361 }
362 
363 static unsigned long
364 ingenic_clk_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
365 {
366 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
367 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
368 	const struct ingenic_cgu_clk_info *clk_info;
369 	unsigned long rate = parent_rate;
370 	u32 div_reg, div;
371 
372 	clk_info = &cgu->clock_info[ingenic_clk->idx];
373 
374 	if (clk_info->type & CGU_CLK_DIV) {
375 		div_reg = readl(cgu->base + clk_info->div.reg);
376 		div = (div_reg >> clk_info->div.shift) &
377 		      GENMASK(clk_info->div.bits - 1, 0);
378 		div += 1;
379 		div *= clk_info->div.div;
380 
381 		rate /= div;
382 	} else if (clk_info->type & CGU_CLK_FIXDIV) {
383 		rate /= clk_info->fixdiv.div;
384 	}
385 
386 	return rate;
387 }
388 
389 static unsigned
390 ingenic_clk_calc_div(const struct ingenic_cgu_clk_info *clk_info,
391 		     unsigned long parent_rate, unsigned long req_rate)
392 {
393 	unsigned div;
394 
395 	/* calculate the divide */
396 	div = DIV_ROUND_UP(parent_rate, req_rate);
397 
398 	/* and impose hardware constraints */
399 	div = min_t(unsigned, div, 1 << clk_info->div.bits);
400 	div = max_t(unsigned, div, 1);
401 
402 	/*
403 	 * If the divider value itself must be divided before being written to
404 	 * the divider register, we must ensure we don't have any bits set that
405 	 * would be lost as a result of doing so.
406 	 */
407 	div /= clk_info->div.div;
408 	div *= clk_info->div.div;
409 
410 	return div;
411 }
412 
413 static long
414 ingenic_clk_round_rate(struct clk_hw *hw, unsigned long req_rate,
415 		       unsigned long *parent_rate)
416 {
417 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
418 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
419 	const struct ingenic_cgu_clk_info *clk_info;
420 	unsigned int div = 1;
421 
422 	clk_info = &cgu->clock_info[ingenic_clk->idx];
423 
424 	if (clk_info->type & CGU_CLK_DIV)
425 		div = ingenic_clk_calc_div(clk_info, *parent_rate, req_rate);
426 	else if (clk_info->type & CGU_CLK_FIXDIV)
427 		div = clk_info->fixdiv.div;
428 
429 	return DIV_ROUND_UP(*parent_rate, div);
430 }
431 
432 static int
433 ingenic_clk_set_rate(struct clk_hw *hw, unsigned long req_rate,
434 		     unsigned long parent_rate)
435 {
436 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
437 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
438 	const struct ingenic_cgu_clk_info *clk_info;
439 	const unsigned timeout = 100;
440 	unsigned long rate, flags;
441 	unsigned div, i;
442 	u32 reg, mask;
443 	int ret = 0;
444 
445 	clk_info = &cgu->clock_info[ingenic_clk->idx];
446 
447 	if (clk_info->type & CGU_CLK_DIV) {
448 		div = ingenic_clk_calc_div(clk_info, parent_rate, req_rate);
449 		rate = DIV_ROUND_UP(parent_rate, div);
450 
451 		if (rate != req_rate)
452 			return -EINVAL;
453 
454 		spin_lock_irqsave(&cgu->lock, flags);
455 		reg = readl(cgu->base + clk_info->div.reg);
456 
457 		/* update the divide */
458 		mask = GENMASK(clk_info->div.bits - 1, 0);
459 		reg &= ~(mask << clk_info->div.shift);
460 		reg |= ((div / clk_info->div.div) - 1) << clk_info->div.shift;
461 
462 		/* clear the stop bit */
463 		if (clk_info->div.stop_bit != -1)
464 			reg &= ~BIT(clk_info->div.stop_bit);
465 
466 		/* set the change enable bit */
467 		if (clk_info->div.ce_bit != -1)
468 			reg |= BIT(clk_info->div.ce_bit);
469 
470 		/* update the hardware */
471 		writel(reg, cgu->base + clk_info->div.reg);
472 
473 		/* wait for the change to take effect */
474 		if (clk_info->div.busy_bit != -1) {
475 			for (i = 0; i < timeout; i++) {
476 				reg = readl(cgu->base + clk_info->div.reg);
477 				if (!(reg & BIT(clk_info->div.busy_bit)))
478 					break;
479 				mdelay(1);
480 			}
481 			if (i == timeout)
482 				ret = -EBUSY;
483 		}
484 
485 		spin_unlock_irqrestore(&cgu->lock, flags);
486 		return ret;
487 	}
488 
489 	return -EINVAL;
490 }
491 
492 static int ingenic_clk_enable(struct clk_hw *hw)
493 {
494 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
495 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
496 	const struct ingenic_cgu_clk_info *clk_info;
497 	unsigned long flags;
498 
499 	clk_info = &cgu->clock_info[ingenic_clk->idx];
500 
501 	if (clk_info->type & CGU_CLK_GATE) {
502 		/* ungate the clock */
503 		spin_lock_irqsave(&cgu->lock, flags);
504 		ingenic_cgu_gate_set(cgu, &clk_info->gate, false);
505 		spin_unlock_irqrestore(&cgu->lock, flags);
506 
507 		if (clk_info->gate.delay_us)
508 			udelay(clk_info->gate.delay_us);
509 	}
510 
511 	return 0;
512 }
513 
514 static void ingenic_clk_disable(struct clk_hw *hw)
515 {
516 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
517 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
518 	const struct ingenic_cgu_clk_info *clk_info;
519 	unsigned long flags;
520 
521 	clk_info = &cgu->clock_info[ingenic_clk->idx];
522 
523 	if (clk_info->type & CGU_CLK_GATE) {
524 		/* gate the clock */
525 		spin_lock_irqsave(&cgu->lock, flags);
526 		ingenic_cgu_gate_set(cgu, &clk_info->gate, true);
527 		spin_unlock_irqrestore(&cgu->lock, flags);
528 	}
529 }
530 
531 static int ingenic_clk_is_enabled(struct clk_hw *hw)
532 {
533 	struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw);
534 	struct ingenic_cgu *cgu = ingenic_clk->cgu;
535 	const struct ingenic_cgu_clk_info *clk_info;
536 	unsigned long flags;
537 	int enabled = 1;
538 
539 	clk_info = &cgu->clock_info[ingenic_clk->idx];
540 
541 	if (clk_info->type & CGU_CLK_GATE) {
542 		spin_lock_irqsave(&cgu->lock, flags);
543 		enabled = !ingenic_cgu_gate_get(cgu, &clk_info->gate);
544 		spin_unlock_irqrestore(&cgu->lock, flags);
545 	}
546 
547 	return enabled;
548 }
549 
550 static const struct clk_ops ingenic_clk_ops = {
551 	.get_parent = ingenic_clk_get_parent,
552 	.set_parent = ingenic_clk_set_parent,
553 
554 	.recalc_rate = ingenic_clk_recalc_rate,
555 	.round_rate = ingenic_clk_round_rate,
556 	.set_rate = ingenic_clk_set_rate,
557 
558 	.enable = ingenic_clk_enable,
559 	.disable = ingenic_clk_disable,
560 	.is_enabled = ingenic_clk_is_enabled,
561 };
562 
563 /*
564  * Setup functions.
565  */
566 
567 static int ingenic_register_clock(struct ingenic_cgu *cgu, unsigned idx)
568 {
569 	const struct ingenic_cgu_clk_info *clk_info = &cgu->clock_info[idx];
570 	struct clk_init_data clk_init;
571 	struct ingenic_clk *ingenic_clk = NULL;
572 	struct clk *clk, *parent;
573 	const char *parent_names[4];
574 	unsigned caps, i, num_possible;
575 	int err = -EINVAL;
576 
577 	BUILD_BUG_ON(ARRAY_SIZE(clk_info->parents) > ARRAY_SIZE(parent_names));
578 
579 	if (clk_info->type == CGU_CLK_EXT) {
580 		clk = of_clk_get_by_name(cgu->np, clk_info->name);
581 		if (IS_ERR(clk)) {
582 			pr_err("%s: no external clock '%s' provided\n",
583 			       __func__, clk_info->name);
584 			err = -ENODEV;
585 			goto out;
586 		}
587 		err = clk_register_clkdev(clk, clk_info->name, NULL);
588 		if (err) {
589 			clk_put(clk);
590 			goto out;
591 		}
592 		cgu->clocks.clks[idx] = clk;
593 		return 0;
594 	}
595 
596 	if (!clk_info->type) {
597 		pr_err("%s: no clock type specified for '%s'\n", __func__,
598 		       clk_info->name);
599 		goto out;
600 	}
601 
602 	ingenic_clk = kzalloc(sizeof(*ingenic_clk), GFP_KERNEL);
603 	if (!ingenic_clk) {
604 		err = -ENOMEM;
605 		goto out;
606 	}
607 
608 	ingenic_clk->hw.init = &clk_init;
609 	ingenic_clk->cgu = cgu;
610 	ingenic_clk->idx = idx;
611 
612 	clk_init.name = clk_info->name;
613 	clk_init.flags = 0;
614 	clk_init.parent_names = parent_names;
615 
616 	caps = clk_info->type;
617 
618 	if (caps & (CGU_CLK_MUX | CGU_CLK_CUSTOM)) {
619 		clk_init.num_parents = 0;
620 
621 		if (caps & CGU_CLK_MUX)
622 			num_possible = 1 << clk_info->mux.bits;
623 		else
624 			num_possible = ARRAY_SIZE(clk_info->parents);
625 
626 		for (i = 0; i < num_possible; i++) {
627 			if (clk_info->parents[i] == -1)
628 				continue;
629 
630 			parent = cgu->clocks.clks[clk_info->parents[i]];
631 			parent_names[clk_init.num_parents] =
632 				__clk_get_name(parent);
633 			clk_init.num_parents++;
634 		}
635 
636 		BUG_ON(!clk_init.num_parents);
637 		BUG_ON(clk_init.num_parents > ARRAY_SIZE(parent_names));
638 	} else {
639 		BUG_ON(clk_info->parents[0] == -1);
640 		clk_init.num_parents = 1;
641 		parent = cgu->clocks.clks[clk_info->parents[0]];
642 		parent_names[0] = __clk_get_name(parent);
643 	}
644 
645 	if (caps & CGU_CLK_CUSTOM) {
646 		clk_init.ops = clk_info->custom.clk_ops;
647 
648 		caps &= ~CGU_CLK_CUSTOM;
649 
650 		if (caps) {
651 			pr_err("%s: custom clock may not be combined with type 0x%x\n",
652 			       __func__, caps);
653 			goto out;
654 		}
655 	} else if (caps & CGU_CLK_PLL) {
656 		clk_init.ops = &ingenic_pll_ops;
657 		clk_init.flags |= CLK_SET_RATE_GATE;
658 
659 		caps &= ~CGU_CLK_PLL;
660 
661 		if (caps) {
662 			pr_err("%s: PLL may not be combined with type 0x%x\n",
663 			       __func__, caps);
664 			goto out;
665 		}
666 	} else {
667 		clk_init.ops = &ingenic_clk_ops;
668 	}
669 
670 	/* nothing to do for gates or fixed dividers */
671 	caps &= ~(CGU_CLK_GATE | CGU_CLK_FIXDIV);
672 
673 	if (caps & CGU_CLK_MUX) {
674 		if (!(caps & CGU_CLK_MUX_GLITCHFREE))
675 			clk_init.flags |= CLK_SET_PARENT_GATE;
676 
677 		caps &= ~(CGU_CLK_MUX | CGU_CLK_MUX_GLITCHFREE);
678 	}
679 
680 	if (caps & CGU_CLK_DIV) {
681 		caps &= ~CGU_CLK_DIV;
682 	} else {
683 		/* pass rate changes to the parent clock */
684 		clk_init.flags |= CLK_SET_RATE_PARENT;
685 	}
686 
687 	if (caps) {
688 		pr_err("%s: unknown clock type 0x%x\n", __func__, caps);
689 		goto out;
690 	}
691 
692 	clk = clk_register(NULL, &ingenic_clk->hw);
693 	if (IS_ERR(clk)) {
694 		pr_err("%s: failed to register clock '%s'\n", __func__,
695 		       clk_info->name);
696 		err = PTR_ERR(clk);
697 		goto out;
698 	}
699 
700 	err = clk_register_clkdev(clk, clk_info->name, NULL);
701 	if (err)
702 		goto out;
703 
704 	cgu->clocks.clks[idx] = clk;
705 out:
706 	if (err)
707 		kfree(ingenic_clk);
708 	return err;
709 }
710 
711 struct ingenic_cgu *
712 ingenic_cgu_new(const struct ingenic_cgu_clk_info *clock_info,
713 		unsigned num_clocks, struct device_node *np)
714 {
715 	struct ingenic_cgu *cgu;
716 
717 	cgu = kzalloc(sizeof(*cgu), GFP_KERNEL);
718 	if (!cgu)
719 		goto err_out;
720 
721 	cgu->base = of_iomap(np, 0);
722 	if (!cgu->base) {
723 		pr_err("%s: failed to map CGU registers\n", __func__);
724 		goto err_out_free;
725 	}
726 
727 	cgu->np = np;
728 	cgu->clock_info = clock_info;
729 	cgu->clocks.clk_num = num_clocks;
730 
731 	spin_lock_init(&cgu->lock);
732 
733 	return cgu;
734 
735 err_out_free:
736 	kfree(cgu);
737 err_out:
738 	return NULL;
739 }
740 
741 int ingenic_cgu_register_clocks(struct ingenic_cgu *cgu)
742 {
743 	unsigned i;
744 	int err;
745 
746 	cgu->clocks.clks = kcalloc(cgu->clocks.clk_num, sizeof(struct clk *),
747 				   GFP_KERNEL);
748 	if (!cgu->clocks.clks) {
749 		err = -ENOMEM;
750 		goto err_out;
751 	}
752 
753 	for (i = 0; i < cgu->clocks.clk_num; i++) {
754 		err = ingenic_register_clock(cgu, i);
755 		if (err)
756 			goto err_out_unregister;
757 	}
758 
759 	err = of_clk_add_provider(cgu->np, of_clk_src_onecell_get,
760 				  &cgu->clocks);
761 	if (err)
762 		goto err_out_unregister;
763 
764 	return 0;
765 
766 err_out_unregister:
767 	for (i = 0; i < cgu->clocks.clk_num; i++) {
768 		if (!cgu->clocks.clks[i])
769 			continue;
770 		if (cgu->clock_info[i].type & CGU_CLK_EXT)
771 			clk_put(cgu->clocks.clks[i]);
772 		else
773 			clk_unregister(cgu->clocks.clks[i]);
774 	}
775 	kfree(cgu->clocks.clks);
776 err_out:
777 	return err;
778 }
779