xref: /linux/drivers/clk/clk-xgene.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
1 /*
2  * clk-xgene.c - AppliedMicro X-Gene Clock Interface
3  *
4  * Copyright (c) 2013, Applied Micro Circuits Corporation
5  * Author: Loc Ho <lho@apm.com>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License as
9  * published by the Free Software Foundation; either version 2 of
10  * the License, or (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
20  * MA 02111-1307 USA
21  *
22  */
23 #include <linux/module.h>
24 #include <linux/spinlock.h>
25 #include <linux/io.h>
26 #include <linux/of.h>
27 #include <linux/clkdev.h>
28 #include <linux/clk-provider.h>
29 #include <linux/of_address.h>
30 
31 /* Register SCU_PCPPLL bit fields */
32 #define N_DIV_RD(src)			((src) & 0x000001ff)
33 #define SC_N_DIV_RD(src)		((src) & 0x0000007f)
34 #define SC_OUTDIV2(src)			(((src) & 0x00000100) >> 8)
35 
36 /* Register SCU_SOCPLL bit fields */
37 #define CLKR_RD(src)			(((src) & 0x07000000)>>24)
38 #define CLKOD_RD(src)			(((src) & 0x00300000)>>20)
39 #define REGSPEC_RESET_F1_MASK		0x00010000
40 #define CLKF_RD(src)			(((src) & 0x000001ff))
41 
42 #define XGENE_CLK_DRIVER_VER		"0.1"
43 
44 static DEFINE_SPINLOCK(clk_lock);
45 
46 static inline u32 xgene_clk_read(void __iomem *csr)
47 {
48 	return readl_relaxed(csr);
49 }
50 
51 static inline void xgene_clk_write(u32 data, void __iomem *csr)
52 {
53 	writel_relaxed(data, csr);
54 }
55 
56 /* PLL Clock */
57 enum xgene_pll_type {
58 	PLL_TYPE_PCP = 0,
59 	PLL_TYPE_SOC = 1,
60 };
61 
62 struct xgene_clk_pll {
63 	struct clk_hw	hw;
64 	void __iomem	*reg;
65 	spinlock_t	*lock;
66 	u32		pll_offset;
67 	enum xgene_pll_type	type;
68 	int		version;
69 };
70 
71 #define to_xgene_clk_pll(_hw) container_of(_hw, struct xgene_clk_pll, hw)
72 
73 static int xgene_clk_pll_is_enabled(struct clk_hw *hw)
74 {
75 	struct xgene_clk_pll *pllclk = to_xgene_clk_pll(hw);
76 	u32 data;
77 
78 	data = xgene_clk_read(pllclk->reg + pllclk->pll_offset);
79 	pr_debug("%s pll %s\n", clk_hw_get_name(hw),
80 		data & REGSPEC_RESET_F1_MASK ? "disabled" : "enabled");
81 
82 	return data & REGSPEC_RESET_F1_MASK ? 0 : 1;
83 }
84 
85 static unsigned long xgene_clk_pll_recalc_rate(struct clk_hw *hw,
86 				unsigned long parent_rate)
87 {
88 	struct xgene_clk_pll *pllclk = to_xgene_clk_pll(hw);
89 	unsigned long fref;
90 	unsigned long fvco;
91 	u32 pll;
92 	u32 nref;
93 	u32 nout;
94 	u32 nfb;
95 
96 	pll = xgene_clk_read(pllclk->reg + pllclk->pll_offset);
97 
98 	if (pllclk->version <= 1) {
99 		if (pllclk->type == PLL_TYPE_PCP) {
100 			/*
101 			* PLL VCO = Reference clock * NF
102 			* PCP PLL = PLL_VCO / 2
103 			*/
104 			nout = 2;
105 			fvco = parent_rate * (N_DIV_RD(pll) + 4);
106 		} else {
107 			/*
108 			* Fref = Reference Clock / NREF;
109 			* Fvco = Fref * NFB;
110 			* Fout = Fvco / NOUT;
111 			*/
112 			nref = CLKR_RD(pll) + 1;
113 			nout = CLKOD_RD(pll) + 1;
114 			nfb = CLKF_RD(pll);
115 			fref = parent_rate / nref;
116 			fvco = fref * nfb;
117 		}
118 	} else {
119 		/*
120 		 * fvco = Reference clock * FBDIVC
121 		 * PLL freq = fvco / NOUT
122 		 */
123 		nout = SC_OUTDIV2(pll) ? 2 : 3;
124 		fvco = parent_rate * SC_N_DIV_RD(pll);
125 	}
126 	pr_debug("%s pll recalc rate %ld parent %ld version %d\n",
127 		 clk_hw_get_name(hw), fvco / nout, parent_rate,
128 		 pllclk->version);
129 
130 	return fvco / nout;
131 }
132 
133 static const struct clk_ops xgene_clk_pll_ops = {
134 	.is_enabled = xgene_clk_pll_is_enabled,
135 	.recalc_rate = xgene_clk_pll_recalc_rate,
136 };
137 
138 static struct clk *xgene_register_clk_pll(struct device *dev,
139 	const char *name, const char *parent_name,
140 	unsigned long flags, void __iomem *reg, u32 pll_offset,
141 	u32 type, spinlock_t *lock, int version)
142 {
143 	struct xgene_clk_pll *apmclk;
144 	struct clk *clk;
145 	struct clk_init_data init;
146 
147 	/* allocate the APM clock structure */
148 	apmclk = kzalloc(sizeof(*apmclk), GFP_KERNEL);
149 	if (!apmclk) {
150 		pr_err("%s: could not allocate APM clk\n", __func__);
151 		return ERR_PTR(-ENOMEM);
152 	}
153 
154 	init.name = name;
155 	init.ops = &xgene_clk_pll_ops;
156 	init.flags = flags;
157 	init.parent_names = parent_name ? &parent_name : NULL;
158 	init.num_parents = parent_name ? 1 : 0;
159 
160 	apmclk->version = version;
161 	apmclk->reg = reg;
162 	apmclk->lock = lock;
163 	apmclk->pll_offset = pll_offset;
164 	apmclk->type = type;
165 	apmclk->hw.init = &init;
166 
167 	/* Register the clock */
168 	clk = clk_register(dev, &apmclk->hw);
169 	if (IS_ERR(clk)) {
170 		pr_err("%s: could not register clk %s\n", __func__, name);
171 		kfree(apmclk);
172 		return NULL;
173 	}
174 	return clk;
175 }
176 
177 static int xgene_pllclk_version(struct device_node *np)
178 {
179 	if (of_device_is_compatible(np, "apm,xgene-socpll-clock"))
180 		return 1;
181 	if (of_device_is_compatible(np, "apm,xgene-pcppll-clock"))
182 		return 1;
183 	return 2;
184 }
185 
186 static void xgene_pllclk_init(struct device_node *np, enum xgene_pll_type pll_type)
187 {
188 	const char *clk_name = np->full_name;
189 	struct clk *clk;
190 	void __iomem *reg;
191 	int version = xgene_pllclk_version(np);
192 
193 	reg = of_iomap(np, 0);
194 	if (reg == NULL) {
195 		pr_err("Unable to map CSR register for %s\n", np->full_name);
196 		return;
197 	}
198 	of_property_read_string(np, "clock-output-names", &clk_name);
199 	clk = xgene_register_clk_pll(NULL,
200 			clk_name, of_clk_get_parent_name(np, 0),
201 			0, reg, 0, pll_type, &clk_lock,
202 			version);
203 	if (!IS_ERR(clk)) {
204 		of_clk_add_provider(np, of_clk_src_simple_get, clk);
205 		clk_register_clkdev(clk, clk_name, NULL);
206 		pr_debug("Add %s clock PLL\n", clk_name);
207 	}
208 }
209 
210 static void xgene_socpllclk_init(struct device_node *np)
211 {
212 	xgene_pllclk_init(np, PLL_TYPE_SOC);
213 }
214 
215 static void xgene_pcppllclk_init(struct device_node *np)
216 {
217 	xgene_pllclk_init(np, PLL_TYPE_PCP);
218 }
219 
220 /**
221  * struct xgene_clk_pmd - PMD clock
222  *
223  * @hw:		handle between common and hardware-specific interfaces
224  * @reg:	register containing the fractional scale multiplier (scaler)
225  * @shift:	shift to the unit bit field
226  * @denom:	1/denominator unit
227  * @lock:	register lock
228  * Flags:
229  * XGENE_CLK_PMD_SCALE_INVERTED - By default the scaler is the value read
230  *	from the register plus one. For example,
231  *		0 for (0 + 1) / denom,
232  *		1 for (1 + 1) / denom and etc.
233  *	If this flag is set, it is
234  *		0 for (denom - 0) / denom,
235  *		1 for (denom - 1) / denom and etc.
236  *
237  */
238 struct xgene_clk_pmd {
239 	struct clk_hw	hw;
240 	void __iomem	*reg;
241 	u8		shift;
242 	u32		mask;
243 	u64		denom;
244 	u32		flags;
245 	spinlock_t	*lock;
246 };
247 
248 #define to_xgene_clk_pmd(_hw) container_of(_hw, struct xgene_clk_pmd, hw)
249 
250 #define XGENE_CLK_PMD_SCALE_INVERTED	BIT(0)
251 #define XGENE_CLK_PMD_SHIFT		8
252 #define XGENE_CLK_PMD_WIDTH		3
253 
254 static unsigned long xgene_clk_pmd_recalc_rate(struct clk_hw *hw,
255 					       unsigned long parent_rate)
256 {
257 	struct xgene_clk_pmd *fd = to_xgene_clk_pmd(hw);
258 	unsigned long flags = 0;
259 	u64 ret, scale;
260 	u32 val;
261 
262 	if (fd->lock)
263 		spin_lock_irqsave(fd->lock, flags);
264 	else
265 		__acquire(fd->lock);
266 
267 	val = clk_readl(fd->reg);
268 
269 	if (fd->lock)
270 		spin_unlock_irqrestore(fd->lock, flags);
271 	else
272 		__release(fd->lock);
273 
274 	ret = (u64)parent_rate;
275 
276 	scale = (val & fd->mask) >> fd->shift;
277 	if (fd->flags & XGENE_CLK_PMD_SCALE_INVERTED)
278 		scale = fd->denom - scale;
279 	else
280 		scale++;
281 
282 	/* freq = parent_rate * scaler / denom */
283 	do_div(ret, fd->denom);
284 	ret *= scale;
285 	if (ret == 0)
286 		ret = (u64)parent_rate;
287 
288 	return ret;
289 }
290 
291 static long xgene_clk_pmd_round_rate(struct clk_hw *hw, unsigned long rate,
292 				     unsigned long *parent_rate)
293 {
294 	struct xgene_clk_pmd *fd = to_xgene_clk_pmd(hw);
295 	u64 ret, scale;
296 
297 	if (!rate || rate >= *parent_rate)
298 		return *parent_rate;
299 
300 	/* freq = parent_rate * scaler / denom */
301 	ret = rate * fd->denom;
302 	scale = DIV_ROUND_UP_ULL(ret, *parent_rate);
303 
304 	ret = (u64)*parent_rate * scale;
305 	do_div(ret, fd->denom);
306 
307 	return ret;
308 }
309 
310 static int xgene_clk_pmd_set_rate(struct clk_hw *hw, unsigned long rate,
311 				  unsigned long parent_rate)
312 {
313 	struct xgene_clk_pmd *fd = to_xgene_clk_pmd(hw);
314 	unsigned long flags = 0;
315 	u64 scale, ret;
316 	u32 val;
317 
318 	/*
319 	 * Compute the scaler:
320 	 *
321 	 * freq = parent_rate * scaler / denom, or
322 	 * scaler = freq * denom / parent_rate
323 	 */
324 	ret = rate * fd->denom;
325 	scale = DIV_ROUND_UP_ULL(ret, (u64)parent_rate);
326 
327 	/* Check if inverted */
328 	if (fd->flags & XGENE_CLK_PMD_SCALE_INVERTED)
329 		scale = fd->denom - scale;
330 	else
331 		scale--;
332 
333 	if (fd->lock)
334 		spin_lock_irqsave(fd->lock, flags);
335 	else
336 		__acquire(fd->lock);
337 
338 	val = clk_readl(fd->reg);
339 	val &= ~fd->mask;
340 	val |= (scale << fd->shift);
341 	clk_writel(val, fd->reg);
342 
343 	if (fd->lock)
344 		spin_unlock_irqrestore(fd->lock, flags);
345 	else
346 		__release(fd->lock);
347 
348 	return 0;
349 }
350 
351 static const struct clk_ops xgene_clk_pmd_ops = {
352 	.recalc_rate = xgene_clk_pmd_recalc_rate,
353 	.round_rate = xgene_clk_pmd_round_rate,
354 	.set_rate = xgene_clk_pmd_set_rate,
355 };
356 
357 static struct clk *
358 xgene_register_clk_pmd(struct device *dev,
359 		       const char *name, const char *parent_name,
360 		       unsigned long flags, void __iomem *reg, u8 shift,
361 		       u8 width, u64 denom, u32 clk_flags, spinlock_t *lock)
362 {
363 	struct xgene_clk_pmd *fd;
364 	struct clk_init_data init;
365 	struct clk *clk;
366 
367 	fd = kzalloc(sizeof(*fd), GFP_KERNEL);
368 	if (!fd)
369 		return ERR_PTR(-ENOMEM);
370 
371 	init.name = name;
372 	init.ops = &xgene_clk_pmd_ops;
373 	init.flags = flags;
374 	init.parent_names = parent_name ? &parent_name : NULL;
375 	init.num_parents = parent_name ? 1 : 0;
376 
377 	fd->reg = reg;
378 	fd->shift = shift;
379 	fd->mask = (BIT(width) - 1) << shift;
380 	fd->denom = denom;
381 	fd->flags = clk_flags;
382 	fd->lock = lock;
383 	fd->hw.init = &init;
384 
385 	clk = clk_register(dev, &fd->hw);
386 	if (IS_ERR(clk)) {
387 		pr_err("%s: could not register clk %s\n", __func__, name);
388 		kfree(fd);
389 		return NULL;
390 	}
391 
392 	return clk;
393 }
394 
395 static void xgene_pmdclk_init(struct device_node *np)
396 {
397 	const char *clk_name = np->full_name;
398 	void __iomem *csr_reg;
399 	struct resource res;
400 	struct clk *clk;
401 	u64 denom;
402 	u32 flags = 0;
403 	int rc;
404 
405 	/* Check if the entry is disabled */
406 	if (!of_device_is_available(np))
407 		return;
408 
409 	/* Parse the DTS register for resource */
410 	rc = of_address_to_resource(np, 0, &res);
411 	if (rc != 0) {
412 		pr_err("no DTS register for %s\n", np->full_name);
413 		return;
414 	}
415 	csr_reg = of_iomap(np, 0);
416 	if (!csr_reg) {
417 		pr_err("Unable to map resource for %s\n", np->full_name);
418 		return;
419 	}
420 	of_property_read_string(np, "clock-output-names", &clk_name);
421 
422 	denom = BIT(XGENE_CLK_PMD_WIDTH);
423 	flags |= XGENE_CLK_PMD_SCALE_INVERTED;
424 
425 	clk = xgene_register_clk_pmd(NULL, clk_name,
426 				     of_clk_get_parent_name(np, 0), 0,
427 				     csr_reg, XGENE_CLK_PMD_SHIFT,
428 				     XGENE_CLK_PMD_WIDTH, denom,
429 				     flags, &clk_lock);
430 	if (!IS_ERR(clk)) {
431 		of_clk_add_provider(np, of_clk_src_simple_get, clk);
432 		clk_register_clkdev(clk, clk_name, NULL);
433 		pr_debug("Add %s clock\n", clk_name);
434 	} else {
435 		if (csr_reg)
436 			iounmap(csr_reg);
437 	}
438 }
439 
440 /* IP Clock */
441 struct xgene_dev_parameters {
442 	void __iomem *csr_reg;		/* CSR for IP clock */
443 	u32 reg_clk_offset;		/* Offset to clock enable CSR */
444 	u32 reg_clk_mask;		/* Mask bit for clock enable */
445 	u32 reg_csr_offset;		/* Offset to CSR reset */
446 	u32 reg_csr_mask;		/* Mask bit for disable CSR reset */
447 	void __iomem *divider_reg;	/* CSR for divider */
448 	u32 reg_divider_offset;		/* Offset to divider register */
449 	u32 reg_divider_shift;		/* Bit shift to divider field */
450 	u32 reg_divider_width;		/* Width of the bit to divider field */
451 };
452 
453 struct xgene_clk {
454 	struct clk_hw	hw;
455 	spinlock_t	*lock;
456 	struct xgene_dev_parameters	param;
457 };
458 
459 #define to_xgene_clk(_hw) container_of(_hw, struct xgene_clk, hw)
460 
461 static int xgene_clk_enable(struct clk_hw *hw)
462 {
463 	struct xgene_clk *pclk = to_xgene_clk(hw);
464 	unsigned long flags = 0;
465 	u32 data;
466 
467 	if (pclk->lock)
468 		spin_lock_irqsave(pclk->lock, flags);
469 
470 	if (pclk->param.csr_reg != NULL) {
471 		pr_debug("%s clock enabled\n", clk_hw_get_name(hw));
472 		/* First enable the clock */
473 		data = xgene_clk_read(pclk->param.csr_reg +
474 					pclk->param.reg_clk_offset);
475 		data |= pclk->param.reg_clk_mask;
476 		xgene_clk_write(data, pclk->param.csr_reg +
477 					pclk->param.reg_clk_offset);
478 		pr_debug("%s clk offset 0x%08X mask 0x%08X value 0x%08X\n",
479 			clk_hw_get_name(hw),
480 			pclk->param.reg_clk_offset, pclk->param.reg_clk_mask,
481 			data);
482 
483 		/* Second enable the CSR */
484 		data = xgene_clk_read(pclk->param.csr_reg +
485 					pclk->param.reg_csr_offset);
486 		data &= ~pclk->param.reg_csr_mask;
487 		xgene_clk_write(data, pclk->param.csr_reg +
488 					pclk->param.reg_csr_offset);
489 		pr_debug("%s csr offset 0x%08X mask 0x%08X value 0x%08X\n",
490 			clk_hw_get_name(hw),
491 			pclk->param.reg_csr_offset, pclk->param.reg_csr_mask,
492 			data);
493 	}
494 
495 	if (pclk->lock)
496 		spin_unlock_irqrestore(pclk->lock, flags);
497 
498 	return 0;
499 }
500 
501 static void xgene_clk_disable(struct clk_hw *hw)
502 {
503 	struct xgene_clk *pclk = to_xgene_clk(hw);
504 	unsigned long flags = 0;
505 	u32 data;
506 
507 	if (pclk->lock)
508 		spin_lock_irqsave(pclk->lock, flags);
509 
510 	if (pclk->param.csr_reg != NULL) {
511 		pr_debug("%s clock disabled\n", clk_hw_get_name(hw));
512 		/* First put the CSR in reset */
513 		data = xgene_clk_read(pclk->param.csr_reg +
514 					pclk->param.reg_csr_offset);
515 		data |= pclk->param.reg_csr_mask;
516 		xgene_clk_write(data, pclk->param.csr_reg +
517 					pclk->param.reg_csr_offset);
518 
519 		/* Second disable the clock */
520 		data = xgene_clk_read(pclk->param.csr_reg +
521 					pclk->param.reg_clk_offset);
522 		data &= ~pclk->param.reg_clk_mask;
523 		xgene_clk_write(data, pclk->param.csr_reg +
524 					pclk->param.reg_clk_offset);
525 	}
526 
527 	if (pclk->lock)
528 		spin_unlock_irqrestore(pclk->lock, flags);
529 }
530 
531 static int xgene_clk_is_enabled(struct clk_hw *hw)
532 {
533 	struct xgene_clk *pclk = to_xgene_clk(hw);
534 	u32 data = 0;
535 
536 	if (pclk->param.csr_reg != NULL) {
537 		pr_debug("%s clock checking\n", clk_hw_get_name(hw));
538 		data = xgene_clk_read(pclk->param.csr_reg +
539 					pclk->param.reg_clk_offset);
540 		pr_debug("%s clock is %s\n", clk_hw_get_name(hw),
541 			data & pclk->param.reg_clk_mask ? "enabled" :
542 							"disabled");
543 	}
544 
545 	if (pclk->param.csr_reg == NULL)
546 		return 1;
547 	return data & pclk->param.reg_clk_mask ? 1 : 0;
548 }
549 
550 static unsigned long xgene_clk_recalc_rate(struct clk_hw *hw,
551 				unsigned long parent_rate)
552 {
553 	struct xgene_clk *pclk = to_xgene_clk(hw);
554 	u32 data;
555 
556 	if (pclk->param.divider_reg) {
557 		data = xgene_clk_read(pclk->param.divider_reg +
558 					pclk->param.reg_divider_offset);
559 		data >>= pclk->param.reg_divider_shift;
560 		data &= (1 << pclk->param.reg_divider_width) - 1;
561 
562 		pr_debug("%s clock recalc rate %ld parent %ld\n",
563 			clk_hw_get_name(hw),
564 			parent_rate / data, parent_rate);
565 
566 		return parent_rate / data;
567 	} else {
568 		pr_debug("%s clock recalc rate %ld parent %ld\n",
569 			clk_hw_get_name(hw), parent_rate, parent_rate);
570 		return parent_rate;
571 	}
572 }
573 
574 static int xgene_clk_set_rate(struct clk_hw *hw, unsigned long rate,
575 				unsigned long parent_rate)
576 {
577 	struct xgene_clk *pclk = to_xgene_clk(hw);
578 	unsigned long flags = 0;
579 	u32 data;
580 	u32 divider;
581 	u32 divider_save;
582 
583 	if (pclk->lock)
584 		spin_lock_irqsave(pclk->lock, flags);
585 
586 	if (pclk->param.divider_reg) {
587 		/* Let's compute the divider */
588 		if (rate > parent_rate)
589 			rate = parent_rate;
590 		divider_save = divider = parent_rate / rate; /* Rounded down */
591 		divider &= (1 << pclk->param.reg_divider_width) - 1;
592 		divider <<= pclk->param.reg_divider_shift;
593 
594 		/* Set new divider */
595 		data = xgene_clk_read(pclk->param.divider_reg +
596 				pclk->param.reg_divider_offset);
597 		data &= ~(((1 << pclk->param.reg_divider_width) - 1)
598 				<< pclk->param.reg_divider_shift);
599 		data |= divider;
600 		xgene_clk_write(data, pclk->param.divider_reg +
601 					pclk->param.reg_divider_offset);
602 		pr_debug("%s clock set rate %ld\n", clk_hw_get_name(hw),
603 			parent_rate / divider_save);
604 	} else {
605 		divider_save = 1;
606 	}
607 
608 	if (pclk->lock)
609 		spin_unlock_irqrestore(pclk->lock, flags);
610 
611 	return parent_rate / divider_save;
612 }
613 
614 static long xgene_clk_round_rate(struct clk_hw *hw, unsigned long rate,
615 				unsigned long *prate)
616 {
617 	struct xgene_clk *pclk = to_xgene_clk(hw);
618 	unsigned long parent_rate = *prate;
619 	u32 divider;
620 
621 	if (pclk->param.divider_reg) {
622 		/* Let's compute the divider */
623 		if (rate > parent_rate)
624 			rate = parent_rate;
625 		divider = parent_rate / rate;   /* Rounded down */
626 	} else {
627 		divider = 1;
628 	}
629 
630 	return parent_rate / divider;
631 }
632 
633 static const struct clk_ops xgene_clk_ops = {
634 	.enable = xgene_clk_enable,
635 	.disable = xgene_clk_disable,
636 	.is_enabled = xgene_clk_is_enabled,
637 	.recalc_rate = xgene_clk_recalc_rate,
638 	.set_rate = xgene_clk_set_rate,
639 	.round_rate = xgene_clk_round_rate,
640 };
641 
642 static struct clk *xgene_register_clk(struct device *dev,
643 		const char *name, const char *parent_name,
644 		struct xgene_dev_parameters *parameters, spinlock_t *lock)
645 {
646 	struct xgene_clk *apmclk;
647 	struct clk *clk;
648 	struct clk_init_data init;
649 	int rc;
650 
651 	/* allocate the APM clock structure */
652 	apmclk = kzalloc(sizeof(*apmclk), GFP_KERNEL);
653 	if (!apmclk) {
654 		pr_err("%s: could not allocate APM clk\n", __func__);
655 		return ERR_PTR(-ENOMEM);
656 	}
657 
658 	init.name = name;
659 	init.ops = &xgene_clk_ops;
660 	init.flags = 0;
661 	init.parent_names = parent_name ? &parent_name : NULL;
662 	init.num_parents = parent_name ? 1 : 0;
663 
664 	apmclk->lock = lock;
665 	apmclk->hw.init = &init;
666 	apmclk->param = *parameters;
667 
668 	/* Register the clock */
669 	clk = clk_register(dev, &apmclk->hw);
670 	if (IS_ERR(clk)) {
671 		pr_err("%s: could not register clk %s\n", __func__, name);
672 		kfree(apmclk);
673 		return clk;
674 	}
675 
676 	/* Register the clock for lookup */
677 	rc = clk_register_clkdev(clk, name, NULL);
678 	if (rc != 0) {
679 		pr_err("%s: could not register lookup clk %s\n",
680 			__func__, name);
681 	}
682 	return clk;
683 }
684 
685 static void __init xgene_devclk_init(struct device_node *np)
686 {
687 	const char *clk_name = np->full_name;
688 	struct clk *clk;
689 	struct resource res;
690 	int rc;
691 	struct xgene_dev_parameters parameters;
692 	int i;
693 
694 	/* Check if the entry is disabled */
695         if (!of_device_is_available(np))
696                 return;
697 
698 	/* Parse the DTS register for resource */
699 	parameters.csr_reg = NULL;
700 	parameters.divider_reg = NULL;
701 	for (i = 0; i < 2; i++) {
702 		void __iomem *map_res;
703 		rc = of_address_to_resource(np, i, &res);
704 		if (rc != 0) {
705 			if (i == 0) {
706 				pr_err("no DTS register for %s\n",
707 					np->full_name);
708 				return;
709 			}
710 			break;
711 		}
712 		map_res = of_iomap(np, i);
713 		if (map_res == NULL) {
714 			pr_err("Unable to map resource %d for %s\n",
715 				i, np->full_name);
716 			goto err;
717 		}
718 		if (strcmp(res.name, "div-reg") == 0)
719 			parameters.divider_reg = map_res;
720 		else /* if (strcmp(res->name, "csr-reg") == 0) */
721 			parameters.csr_reg = map_res;
722 	}
723 	if (of_property_read_u32(np, "csr-offset", &parameters.reg_csr_offset))
724 		parameters.reg_csr_offset = 0;
725 	if (of_property_read_u32(np, "csr-mask", &parameters.reg_csr_mask))
726 		parameters.reg_csr_mask = 0xF;
727 	if (of_property_read_u32(np, "enable-offset",
728 				&parameters.reg_clk_offset))
729 		parameters.reg_clk_offset = 0x8;
730 	if (of_property_read_u32(np, "enable-mask", &parameters.reg_clk_mask))
731 		parameters.reg_clk_mask = 0xF;
732 	if (of_property_read_u32(np, "divider-offset",
733 				&parameters.reg_divider_offset))
734 		parameters.reg_divider_offset = 0;
735 	if (of_property_read_u32(np, "divider-width",
736 				&parameters.reg_divider_width))
737 		parameters.reg_divider_width = 0;
738 	if (of_property_read_u32(np, "divider-shift",
739 				&parameters.reg_divider_shift))
740 		parameters.reg_divider_shift = 0;
741 	of_property_read_string(np, "clock-output-names", &clk_name);
742 
743 	clk = xgene_register_clk(NULL, clk_name,
744 		of_clk_get_parent_name(np, 0), &parameters, &clk_lock);
745 	if (IS_ERR(clk))
746 		goto err;
747 	pr_debug("Add %s clock\n", clk_name);
748 	rc = of_clk_add_provider(np, of_clk_src_simple_get, clk);
749 	if (rc != 0)
750 		pr_err("%s: could register provider clk %s\n", __func__,
751 			np->full_name);
752 
753 	return;
754 
755 err:
756 	if (parameters.csr_reg)
757 		iounmap(parameters.csr_reg);
758 	if (parameters.divider_reg)
759 		iounmap(parameters.divider_reg);
760 }
761 
762 CLK_OF_DECLARE(xgene_socpll_clock, "apm,xgene-socpll-clock", xgene_socpllclk_init);
763 CLK_OF_DECLARE(xgene_pcppll_clock, "apm,xgene-pcppll-clock", xgene_pcppllclk_init);
764 CLK_OF_DECLARE(xgene_pmd_clock, "apm,xgene-pmd-clock", xgene_pmdclk_init);
765 CLK_OF_DECLARE(xgene_socpll_v2_clock, "apm,xgene-socpll-v2-clock",
766 	       xgene_socpllclk_init);
767 CLK_OF_DECLARE(xgene_pcppll_v2_clock, "apm,xgene-pcppll-v2-clock",
768 	       xgene_pcppllclk_init);
769 CLK_OF_DECLARE(xgene_dev_clock, "apm,xgene-device-clock", xgene_devclk_init);
770