xref: /openbmc/linux/drivers/rtc/rtc-sh.c (revision ac316725)
1 /*
2  * SuperH On-Chip RTC Support
3  *
4  * Copyright (C) 2006 - 2009  Paul Mundt
5  * Copyright (C) 2006  Jamie Lenehan
6  * Copyright (C) 2008  Angelo Castello
7  *
8  * Based on the old arch/sh/kernel/cpu/rtc.c by:
9  *
10  *  Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
11  *  Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
12  *
13  * This file is subject to the terms and conditions of the GNU General Public
14  * License.  See the file "COPYING" in the main directory of this archive
15  * for more details.
16  */
17 #include <linux/module.h>
18 #include <linux/mod_devicetable.h>
19 #include <linux/kernel.h>
20 #include <linux/bcd.h>
21 #include <linux/rtc.h>
22 #include <linux/init.h>
23 #include <linux/platform_device.h>
24 #include <linux/seq_file.h>
25 #include <linux/interrupt.h>
26 #include <linux/spinlock.h>
27 #include <linux/io.h>
28 #include <linux/log2.h>
29 #include <linux/clk.h>
30 #include <linux/slab.h>
31 #ifdef CONFIG_SUPERH
32 #include <asm/rtc.h>
33 #else
34 /* Default values for RZ/A RTC */
35 #define rtc_reg_size		sizeof(u16)
36 #define RTC_BIT_INVERTED        0	/* no chip bugs */
37 #define RTC_CAP_4_DIGIT_YEAR    (1 << 0)
38 #define RTC_DEF_CAPABILITIES    RTC_CAP_4_DIGIT_YEAR
39 #endif
40 
41 #define DRV_NAME	"sh-rtc"
42 
43 #define RTC_REG(r)	((r) * rtc_reg_size)
44 
45 #define R64CNT		RTC_REG(0)
46 
47 #define RSECCNT		RTC_REG(1)	/* RTC sec */
48 #define RMINCNT		RTC_REG(2)	/* RTC min */
49 #define RHRCNT		RTC_REG(3)	/* RTC hour */
50 #define RWKCNT		RTC_REG(4)	/* RTC week */
51 #define RDAYCNT		RTC_REG(5)	/* RTC day */
52 #define RMONCNT		RTC_REG(6)	/* RTC month */
53 #define RYRCNT		RTC_REG(7)	/* RTC year */
54 #define RSECAR		RTC_REG(8)	/* ALARM sec */
55 #define RMINAR		RTC_REG(9)	/* ALARM min */
56 #define RHRAR		RTC_REG(10)	/* ALARM hour */
57 #define RWKAR		RTC_REG(11)	/* ALARM week */
58 #define RDAYAR		RTC_REG(12)	/* ALARM day */
59 #define RMONAR		RTC_REG(13)	/* ALARM month */
60 #define RCR1		RTC_REG(14)	/* Control */
61 #define RCR2		RTC_REG(15)	/* Control */
62 
63 /*
64  * Note on RYRAR and RCR3: Up until this point most of the register
65  * definitions are consistent across all of the available parts. However,
66  * the placement of the optional RYRAR and RCR3 (the RYRAR control
67  * register used to control RYRCNT/RYRAR compare) varies considerably
68  * across various parts, occasionally being mapped in to a completely
69  * unrelated address space. For proper RYRAR support a separate resource
70  * would have to be handed off, but as this is purely optional in
71  * practice, we simply opt not to support it, thereby keeping the code
72  * quite a bit more simplified.
73  */
74 
75 /* ALARM Bits - or with BCD encoded value */
76 #define AR_ENB		0x80	/* Enable for alarm cmp   */
77 
78 /* Period Bits */
79 #define PF_HP		0x100	/* Enable Half Period to support 8,32,128Hz */
80 #define PF_COUNT	0x200	/* Half periodic counter */
81 #define PF_OXS		0x400	/* Periodic One x Second */
82 #define PF_KOU		0x800	/* Kernel or User periodic request 1=kernel */
83 #define PF_MASK		0xf00
84 
85 /* RCR1 Bits */
86 #define RCR1_CF		0x80	/* Carry Flag             */
87 #define RCR1_CIE	0x10	/* Carry Interrupt Enable */
88 #define RCR1_AIE	0x08	/* Alarm Interrupt Enable */
89 #define RCR1_AF		0x01	/* Alarm Flag             */
90 
91 /* RCR2 Bits */
92 #define RCR2_PEF	0x80	/* PEriodic interrupt Flag */
93 #define RCR2_PESMASK	0x70	/* Periodic interrupt Set  */
94 #define RCR2_RTCEN	0x08	/* ENable RTC              */
95 #define RCR2_ADJ	0x04	/* ADJustment (30-second)  */
96 #define RCR2_RESET	0x02	/* Reset bit               */
97 #define RCR2_START	0x01	/* Start bit               */
98 
99 struct sh_rtc {
100 	void __iomem		*regbase;
101 	unsigned long		regsize;
102 	struct resource		*res;
103 	int			alarm_irq;
104 	int			periodic_irq;
105 	int			carry_irq;
106 	struct clk		*clk;
107 	struct rtc_device	*rtc_dev;
108 	spinlock_t		lock;
109 	unsigned long		capabilities;	/* See asm/rtc.h for cap bits */
110 	unsigned short		periodic_freq;
111 };
112 
113 static int __sh_rtc_interrupt(struct sh_rtc *rtc)
114 {
115 	unsigned int tmp, pending;
116 
117 	tmp = readb(rtc->regbase + RCR1);
118 	pending = tmp & RCR1_CF;
119 	tmp &= ~RCR1_CF;
120 	writeb(tmp, rtc->regbase + RCR1);
121 
122 	/* Users have requested One x Second IRQ */
123 	if (pending && rtc->periodic_freq & PF_OXS)
124 		rtc_update_irq(rtc->rtc_dev, 1, RTC_UF | RTC_IRQF);
125 
126 	return pending;
127 }
128 
129 static int __sh_rtc_alarm(struct sh_rtc *rtc)
130 {
131 	unsigned int tmp, pending;
132 
133 	tmp = readb(rtc->regbase + RCR1);
134 	pending = tmp & RCR1_AF;
135 	tmp &= ~(RCR1_AF | RCR1_AIE);
136 	writeb(tmp, rtc->regbase + RCR1);
137 
138 	if (pending)
139 		rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
140 
141 	return pending;
142 }
143 
144 static int __sh_rtc_periodic(struct sh_rtc *rtc)
145 {
146 	struct rtc_device *rtc_dev = rtc->rtc_dev;
147 	struct rtc_task *irq_task;
148 	unsigned int tmp, pending;
149 
150 	tmp = readb(rtc->regbase + RCR2);
151 	pending = tmp & RCR2_PEF;
152 	tmp &= ~RCR2_PEF;
153 	writeb(tmp, rtc->regbase + RCR2);
154 
155 	if (!pending)
156 		return 0;
157 
158 	/* Half period enabled than one skipped and the next notified */
159 	if ((rtc->periodic_freq & PF_HP) && (rtc->periodic_freq & PF_COUNT))
160 		rtc->periodic_freq &= ~PF_COUNT;
161 	else {
162 		if (rtc->periodic_freq & PF_HP)
163 			rtc->periodic_freq |= PF_COUNT;
164 		if (rtc->periodic_freq & PF_KOU) {
165 			spin_lock(&rtc_dev->irq_task_lock);
166 			irq_task = rtc_dev->irq_task;
167 			if (irq_task)
168 				irq_task->func(irq_task->private_data);
169 			spin_unlock(&rtc_dev->irq_task_lock);
170 		} else
171 			rtc_update_irq(rtc->rtc_dev, 1, RTC_PF | RTC_IRQF);
172 	}
173 
174 	return pending;
175 }
176 
177 static irqreturn_t sh_rtc_interrupt(int irq, void *dev_id)
178 {
179 	struct sh_rtc *rtc = dev_id;
180 	int ret;
181 
182 	spin_lock(&rtc->lock);
183 	ret = __sh_rtc_interrupt(rtc);
184 	spin_unlock(&rtc->lock);
185 
186 	return IRQ_RETVAL(ret);
187 }
188 
189 static irqreturn_t sh_rtc_alarm(int irq, void *dev_id)
190 {
191 	struct sh_rtc *rtc = dev_id;
192 	int ret;
193 
194 	spin_lock(&rtc->lock);
195 	ret = __sh_rtc_alarm(rtc);
196 	spin_unlock(&rtc->lock);
197 
198 	return IRQ_RETVAL(ret);
199 }
200 
201 static irqreturn_t sh_rtc_periodic(int irq, void *dev_id)
202 {
203 	struct sh_rtc *rtc = dev_id;
204 	int ret;
205 
206 	spin_lock(&rtc->lock);
207 	ret = __sh_rtc_periodic(rtc);
208 	spin_unlock(&rtc->lock);
209 
210 	return IRQ_RETVAL(ret);
211 }
212 
213 static irqreturn_t sh_rtc_shared(int irq, void *dev_id)
214 {
215 	struct sh_rtc *rtc = dev_id;
216 	int ret;
217 
218 	spin_lock(&rtc->lock);
219 	ret = __sh_rtc_interrupt(rtc);
220 	ret |= __sh_rtc_alarm(rtc);
221 	ret |= __sh_rtc_periodic(rtc);
222 	spin_unlock(&rtc->lock);
223 
224 	return IRQ_RETVAL(ret);
225 }
226 
227 static int sh_rtc_irq_set_state(struct device *dev, int enable)
228 {
229 	struct sh_rtc *rtc = dev_get_drvdata(dev);
230 	unsigned int tmp;
231 
232 	spin_lock_irq(&rtc->lock);
233 
234 	tmp = readb(rtc->regbase + RCR2);
235 
236 	if (enable) {
237 		rtc->periodic_freq |= PF_KOU;
238 		tmp &= ~RCR2_PEF;	/* Clear PES bit */
239 		tmp |= (rtc->periodic_freq & ~PF_HP);	/* Set PES2-0 */
240 	} else {
241 		rtc->periodic_freq &= ~PF_KOU;
242 		tmp &= ~(RCR2_PESMASK | RCR2_PEF);
243 	}
244 
245 	writeb(tmp, rtc->regbase + RCR2);
246 
247 	spin_unlock_irq(&rtc->lock);
248 
249 	return 0;
250 }
251 
252 static int sh_rtc_irq_set_freq(struct device *dev, int freq)
253 {
254 	struct sh_rtc *rtc = dev_get_drvdata(dev);
255 	int tmp, ret = 0;
256 
257 	spin_lock_irq(&rtc->lock);
258 	tmp = rtc->periodic_freq & PF_MASK;
259 
260 	switch (freq) {
261 	case 0:
262 		rtc->periodic_freq = 0x00;
263 		break;
264 	case 1:
265 		rtc->periodic_freq = 0x60;
266 		break;
267 	case 2:
268 		rtc->periodic_freq = 0x50;
269 		break;
270 	case 4:
271 		rtc->periodic_freq = 0x40;
272 		break;
273 	case 8:
274 		rtc->periodic_freq = 0x30 | PF_HP;
275 		break;
276 	case 16:
277 		rtc->periodic_freq = 0x30;
278 		break;
279 	case 32:
280 		rtc->periodic_freq = 0x20 | PF_HP;
281 		break;
282 	case 64:
283 		rtc->periodic_freq = 0x20;
284 		break;
285 	case 128:
286 		rtc->periodic_freq = 0x10 | PF_HP;
287 		break;
288 	case 256:
289 		rtc->periodic_freq = 0x10;
290 		break;
291 	default:
292 		ret = -ENOTSUPP;
293 	}
294 
295 	if (ret == 0)
296 		rtc->periodic_freq |= tmp;
297 
298 	spin_unlock_irq(&rtc->lock);
299 	return ret;
300 }
301 
302 static inline void sh_rtc_setaie(struct device *dev, unsigned int enable)
303 {
304 	struct sh_rtc *rtc = dev_get_drvdata(dev);
305 	unsigned int tmp;
306 
307 	spin_lock_irq(&rtc->lock);
308 
309 	tmp = readb(rtc->regbase + RCR1);
310 
311 	if (enable)
312 		tmp |= RCR1_AIE;
313 	else
314 		tmp &= ~RCR1_AIE;
315 
316 	writeb(tmp, rtc->regbase + RCR1);
317 
318 	spin_unlock_irq(&rtc->lock);
319 }
320 
321 static int sh_rtc_proc(struct device *dev, struct seq_file *seq)
322 {
323 	struct sh_rtc *rtc = dev_get_drvdata(dev);
324 	unsigned int tmp;
325 
326 	tmp = readb(rtc->regbase + RCR1);
327 	seq_printf(seq, "carry_IRQ\t: %s\n", (tmp & RCR1_CIE) ? "yes" : "no");
328 
329 	tmp = readb(rtc->regbase + RCR2);
330 	seq_printf(seq, "periodic_IRQ\t: %s\n",
331 		   (tmp & RCR2_PESMASK) ? "yes" : "no");
332 
333 	return 0;
334 }
335 
336 static inline void sh_rtc_setcie(struct device *dev, unsigned int enable)
337 {
338 	struct sh_rtc *rtc = dev_get_drvdata(dev);
339 	unsigned int tmp;
340 
341 	spin_lock_irq(&rtc->lock);
342 
343 	tmp = readb(rtc->regbase + RCR1);
344 
345 	if (!enable)
346 		tmp &= ~RCR1_CIE;
347 	else
348 		tmp |= RCR1_CIE;
349 
350 	writeb(tmp, rtc->regbase + RCR1);
351 
352 	spin_unlock_irq(&rtc->lock);
353 }
354 
355 static int sh_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
356 {
357 	sh_rtc_setaie(dev, enabled);
358 	return 0;
359 }
360 
361 static int sh_rtc_read_time(struct device *dev, struct rtc_time *tm)
362 {
363 	struct sh_rtc *rtc = dev_get_drvdata(dev);
364 	unsigned int sec128, sec2, yr, yr100, cf_bit;
365 
366 	do {
367 		unsigned int tmp;
368 
369 		spin_lock_irq(&rtc->lock);
370 
371 		tmp = readb(rtc->regbase + RCR1);
372 		tmp &= ~RCR1_CF; /* Clear CF-bit */
373 		tmp |= RCR1_CIE;
374 		writeb(tmp, rtc->regbase + RCR1);
375 
376 		sec128 = readb(rtc->regbase + R64CNT);
377 
378 		tm->tm_sec	= bcd2bin(readb(rtc->regbase + RSECCNT));
379 		tm->tm_min	= bcd2bin(readb(rtc->regbase + RMINCNT));
380 		tm->tm_hour	= bcd2bin(readb(rtc->regbase + RHRCNT));
381 		tm->tm_wday	= bcd2bin(readb(rtc->regbase + RWKCNT));
382 		tm->tm_mday	= bcd2bin(readb(rtc->regbase + RDAYCNT));
383 		tm->tm_mon	= bcd2bin(readb(rtc->regbase + RMONCNT)) - 1;
384 
385 		if (rtc->capabilities & RTC_CAP_4_DIGIT_YEAR) {
386 			yr  = readw(rtc->regbase + RYRCNT);
387 			yr100 = bcd2bin(yr >> 8);
388 			yr &= 0xff;
389 		} else {
390 			yr  = readb(rtc->regbase + RYRCNT);
391 			yr100 = bcd2bin((yr == 0x99) ? 0x19 : 0x20);
392 		}
393 
394 		tm->tm_year = (yr100 * 100 + bcd2bin(yr)) - 1900;
395 
396 		sec2 = readb(rtc->regbase + R64CNT);
397 		cf_bit = readb(rtc->regbase + RCR1) & RCR1_CF;
398 
399 		spin_unlock_irq(&rtc->lock);
400 	} while (cf_bit != 0 || ((sec128 ^ sec2) & RTC_BIT_INVERTED) != 0);
401 
402 #if RTC_BIT_INVERTED != 0
403 	if ((sec128 & RTC_BIT_INVERTED))
404 		tm->tm_sec--;
405 #endif
406 
407 	/* only keep the carry interrupt enabled if UIE is on */
408 	if (!(rtc->periodic_freq & PF_OXS))
409 		sh_rtc_setcie(dev, 0);
410 
411 	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
412 		"mday=%d, mon=%d, year=%d, wday=%d\n",
413 		__func__,
414 		tm->tm_sec, tm->tm_min, tm->tm_hour,
415 		tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday);
416 
417 	return 0;
418 }
419 
420 static int sh_rtc_set_time(struct device *dev, struct rtc_time *tm)
421 {
422 	struct sh_rtc *rtc = dev_get_drvdata(dev);
423 	unsigned int tmp;
424 	int year;
425 
426 	spin_lock_irq(&rtc->lock);
427 
428 	/* Reset pre-scaler & stop RTC */
429 	tmp = readb(rtc->regbase + RCR2);
430 	tmp |= RCR2_RESET;
431 	tmp &= ~RCR2_START;
432 	writeb(tmp, rtc->regbase + RCR2);
433 
434 	writeb(bin2bcd(tm->tm_sec),  rtc->regbase + RSECCNT);
435 	writeb(bin2bcd(tm->tm_min),  rtc->regbase + RMINCNT);
436 	writeb(bin2bcd(tm->tm_hour), rtc->regbase + RHRCNT);
437 	writeb(bin2bcd(tm->tm_wday), rtc->regbase + RWKCNT);
438 	writeb(bin2bcd(tm->tm_mday), rtc->regbase + RDAYCNT);
439 	writeb(bin2bcd(tm->tm_mon + 1), rtc->regbase + RMONCNT);
440 
441 	if (rtc->capabilities & RTC_CAP_4_DIGIT_YEAR) {
442 		year = (bin2bcd((tm->tm_year + 1900) / 100) << 8) |
443 			bin2bcd(tm->tm_year % 100);
444 		writew(year, rtc->regbase + RYRCNT);
445 	} else {
446 		year = tm->tm_year % 100;
447 		writeb(bin2bcd(year), rtc->regbase + RYRCNT);
448 	}
449 
450 	/* Start RTC */
451 	tmp = readb(rtc->regbase + RCR2);
452 	tmp &= ~RCR2_RESET;
453 	tmp |= RCR2_RTCEN | RCR2_START;
454 	writeb(tmp, rtc->regbase + RCR2);
455 
456 	spin_unlock_irq(&rtc->lock);
457 
458 	return 0;
459 }
460 
461 static inline int sh_rtc_read_alarm_value(struct sh_rtc *rtc, int reg_off)
462 {
463 	unsigned int byte;
464 	int value = 0xff;	/* return 0xff for ignored values */
465 
466 	byte = readb(rtc->regbase + reg_off);
467 	if (byte & AR_ENB) {
468 		byte &= ~AR_ENB;	/* strip the enable bit */
469 		value = bcd2bin(byte);
470 	}
471 
472 	return value;
473 }
474 
475 static int sh_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
476 {
477 	struct sh_rtc *rtc = dev_get_drvdata(dev);
478 	struct rtc_time *tm = &wkalrm->time;
479 
480 	spin_lock_irq(&rtc->lock);
481 
482 	tm->tm_sec	= sh_rtc_read_alarm_value(rtc, RSECAR);
483 	tm->tm_min	= sh_rtc_read_alarm_value(rtc, RMINAR);
484 	tm->tm_hour	= sh_rtc_read_alarm_value(rtc, RHRAR);
485 	tm->tm_wday	= sh_rtc_read_alarm_value(rtc, RWKAR);
486 	tm->tm_mday	= sh_rtc_read_alarm_value(rtc, RDAYAR);
487 	tm->tm_mon	= sh_rtc_read_alarm_value(rtc, RMONAR);
488 	if (tm->tm_mon > 0)
489 		tm->tm_mon -= 1; /* RTC is 1-12, tm_mon is 0-11 */
490 
491 	wkalrm->enabled = (readb(rtc->regbase + RCR1) & RCR1_AIE) ? 1 : 0;
492 
493 	spin_unlock_irq(&rtc->lock);
494 
495 	return 0;
496 }
497 
498 static inline void sh_rtc_write_alarm_value(struct sh_rtc *rtc,
499 					    int value, int reg_off)
500 {
501 	/* < 0 for a value that is ignored */
502 	if (value < 0)
503 		writeb(0, rtc->regbase + reg_off);
504 	else
505 		writeb(bin2bcd(value) | AR_ENB,  rtc->regbase + reg_off);
506 }
507 
508 static int sh_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
509 {
510 	struct sh_rtc *rtc = dev_get_drvdata(dev);
511 	unsigned int rcr1;
512 	struct rtc_time *tm = &wkalrm->time;
513 	int mon;
514 
515 	spin_lock_irq(&rtc->lock);
516 
517 	/* disable alarm interrupt and clear the alarm flag */
518 	rcr1 = readb(rtc->regbase + RCR1);
519 	rcr1 &= ~(RCR1_AF | RCR1_AIE);
520 	writeb(rcr1, rtc->regbase + RCR1);
521 
522 	/* set alarm time */
523 	sh_rtc_write_alarm_value(rtc, tm->tm_sec,  RSECAR);
524 	sh_rtc_write_alarm_value(rtc, tm->tm_min,  RMINAR);
525 	sh_rtc_write_alarm_value(rtc, tm->tm_hour, RHRAR);
526 	sh_rtc_write_alarm_value(rtc, tm->tm_wday, RWKAR);
527 	sh_rtc_write_alarm_value(rtc, tm->tm_mday, RDAYAR);
528 	mon = tm->tm_mon;
529 	if (mon >= 0)
530 		mon += 1;
531 	sh_rtc_write_alarm_value(rtc, mon, RMONAR);
532 
533 	if (wkalrm->enabled) {
534 		rcr1 |= RCR1_AIE;
535 		writeb(rcr1, rtc->regbase + RCR1);
536 	}
537 
538 	spin_unlock_irq(&rtc->lock);
539 
540 	return 0;
541 }
542 
543 static const struct rtc_class_ops sh_rtc_ops = {
544 	.read_time	= sh_rtc_read_time,
545 	.set_time	= sh_rtc_set_time,
546 	.read_alarm	= sh_rtc_read_alarm,
547 	.set_alarm	= sh_rtc_set_alarm,
548 	.proc		= sh_rtc_proc,
549 	.alarm_irq_enable = sh_rtc_alarm_irq_enable,
550 };
551 
552 static int __init sh_rtc_probe(struct platform_device *pdev)
553 {
554 	struct sh_rtc *rtc;
555 	struct resource *res;
556 	struct rtc_time r;
557 	char clk_name[6];
558 	int clk_id, ret;
559 
560 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
561 	if (unlikely(!rtc))
562 		return -ENOMEM;
563 
564 	spin_lock_init(&rtc->lock);
565 
566 	/* get periodic/carry/alarm irqs */
567 	ret = platform_get_irq(pdev, 0);
568 	if (unlikely(ret <= 0)) {
569 		dev_err(&pdev->dev, "No IRQ resource\n");
570 		return -ENOENT;
571 	}
572 
573 	rtc->periodic_irq = ret;
574 	rtc->carry_irq = platform_get_irq(pdev, 1);
575 	rtc->alarm_irq = platform_get_irq(pdev, 2);
576 
577 	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
578 	if (!res)
579 		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
580 	if (unlikely(res == NULL)) {
581 		dev_err(&pdev->dev, "No IO resource\n");
582 		return -ENOENT;
583 	}
584 
585 	rtc->regsize = resource_size(res);
586 
587 	rtc->res = devm_request_mem_region(&pdev->dev, res->start,
588 					rtc->regsize, pdev->name);
589 	if (unlikely(!rtc->res))
590 		return -EBUSY;
591 
592 	rtc->regbase = devm_ioremap_nocache(&pdev->dev, rtc->res->start,
593 					rtc->regsize);
594 	if (unlikely(!rtc->regbase))
595 		return -EINVAL;
596 
597 	if (!pdev->dev.of_node) {
598 		clk_id = pdev->id;
599 		/* With a single device, the clock id is still "rtc0" */
600 		if (clk_id < 0)
601 			clk_id = 0;
602 
603 		snprintf(clk_name, sizeof(clk_name), "rtc%d", clk_id);
604 	} else
605 		snprintf(clk_name, sizeof(clk_name), "fck");
606 
607 	rtc->clk = devm_clk_get(&pdev->dev, clk_name);
608 	if (IS_ERR(rtc->clk)) {
609 		/*
610 		 * No error handling for rtc->clk intentionally, not all
611 		 * platforms will have a unique clock for the RTC, and
612 		 * the clk API can handle the struct clk pointer being
613 		 * NULL.
614 		 */
615 		rtc->clk = NULL;
616 	}
617 
618 	clk_enable(rtc->clk);
619 
620 	rtc->capabilities = RTC_DEF_CAPABILITIES;
621 
622 #ifdef CONFIG_SUPERH
623 	if (dev_get_platdata(&pdev->dev)) {
624 		struct sh_rtc_platform_info *pinfo =
625 			dev_get_platdata(&pdev->dev);
626 
627 		/*
628 		 * Some CPUs have special capabilities in addition to the
629 		 * default set. Add those in here.
630 		 */
631 		rtc->capabilities |= pinfo->capabilities;
632 	}
633 #endif
634 
635 	if (rtc->carry_irq <= 0) {
636 		/* register shared periodic/carry/alarm irq */
637 		ret = devm_request_irq(&pdev->dev, rtc->periodic_irq,
638 				sh_rtc_shared, 0, "sh-rtc", rtc);
639 		if (unlikely(ret)) {
640 			dev_err(&pdev->dev,
641 				"request IRQ failed with %d, IRQ %d\n", ret,
642 				rtc->periodic_irq);
643 			goto err_unmap;
644 		}
645 	} else {
646 		/* register periodic/carry/alarm irqs */
647 		ret = devm_request_irq(&pdev->dev, rtc->periodic_irq,
648 				sh_rtc_periodic, 0, "sh-rtc period", rtc);
649 		if (unlikely(ret)) {
650 			dev_err(&pdev->dev,
651 				"request period IRQ failed with %d, IRQ %d\n",
652 				ret, rtc->periodic_irq);
653 			goto err_unmap;
654 		}
655 
656 		ret = devm_request_irq(&pdev->dev, rtc->carry_irq,
657 				sh_rtc_interrupt, 0, "sh-rtc carry", rtc);
658 		if (unlikely(ret)) {
659 			dev_err(&pdev->dev,
660 				"request carry IRQ failed with %d, IRQ %d\n",
661 				ret, rtc->carry_irq);
662 			goto err_unmap;
663 		}
664 
665 		ret = devm_request_irq(&pdev->dev, rtc->alarm_irq,
666 				sh_rtc_alarm, 0, "sh-rtc alarm", rtc);
667 		if (unlikely(ret)) {
668 			dev_err(&pdev->dev,
669 				"request alarm IRQ failed with %d, IRQ %d\n",
670 				ret, rtc->alarm_irq);
671 			goto err_unmap;
672 		}
673 	}
674 
675 	platform_set_drvdata(pdev, rtc);
676 
677 	/* everything disabled by default */
678 	sh_rtc_irq_set_freq(&pdev->dev, 0);
679 	sh_rtc_irq_set_state(&pdev->dev, 0);
680 	sh_rtc_setaie(&pdev->dev, 0);
681 	sh_rtc_setcie(&pdev->dev, 0);
682 
683 	rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "sh",
684 					   &sh_rtc_ops, THIS_MODULE);
685 	if (IS_ERR(rtc->rtc_dev)) {
686 		ret = PTR_ERR(rtc->rtc_dev);
687 		goto err_unmap;
688 	}
689 
690 	rtc->rtc_dev->max_user_freq = 256;
691 
692 	/* reset rtc to epoch 0 if time is invalid */
693 	if (rtc_read_time(rtc->rtc_dev, &r) < 0) {
694 		rtc_time_to_tm(0, &r);
695 		rtc_set_time(rtc->rtc_dev, &r);
696 	}
697 
698 	device_init_wakeup(&pdev->dev, 1);
699 	return 0;
700 
701 err_unmap:
702 	clk_disable(rtc->clk);
703 
704 	return ret;
705 }
706 
707 static int __exit sh_rtc_remove(struct platform_device *pdev)
708 {
709 	struct sh_rtc *rtc = platform_get_drvdata(pdev);
710 
711 	sh_rtc_irq_set_state(&pdev->dev, 0);
712 
713 	sh_rtc_setaie(&pdev->dev, 0);
714 	sh_rtc_setcie(&pdev->dev, 0);
715 
716 	clk_disable(rtc->clk);
717 
718 	return 0;
719 }
720 
721 static void sh_rtc_set_irq_wake(struct device *dev, int enabled)
722 {
723 	struct sh_rtc *rtc = dev_get_drvdata(dev);
724 
725 	irq_set_irq_wake(rtc->periodic_irq, enabled);
726 
727 	if (rtc->carry_irq > 0) {
728 		irq_set_irq_wake(rtc->carry_irq, enabled);
729 		irq_set_irq_wake(rtc->alarm_irq, enabled);
730 	}
731 }
732 
733 static int __maybe_unused sh_rtc_suspend(struct device *dev)
734 {
735 	if (device_may_wakeup(dev))
736 		sh_rtc_set_irq_wake(dev, 1);
737 
738 	return 0;
739 }
740 
741 static int __maybe_unused sh_rtc_resume(struct device *dev)
742 {
743 	if (device_may_wakeup(dev))
744 		sh_rtc_set_irq_wake(dev, 0);
745 
746 	return 0;
747 }
748 
749 static SIMPLE_DEV_PM_OPS(sh_rtc_pm_ops, sh_rtc_suspend, sh_rtc_resume);
750 
751 static const struct of_device_id sh_rtc_of_match[] = {
752 	{ .compatible = "renesas,sh-rtc", },
753 	{ /* sentinel */ }
754 };
755 MODULE_DEVICE_TABLE(of, sh_rtc_of_match);
756 
757 static struct platform_driver sh_rtc_platform_driver = {
758 	.driver		= {
759 		.name	= DRV_NAME,
760 		.pm	= &sh_rtc_pm_ops,
761 		.of_match_table = sh_rtc_of_match,
762 	},
763 	.remove		= __exit_p(sh_rtc_remove),
764 };
765 
766 module_platform_driver_probe(sh_rtc_platform_driver, sh_rtc_probe);
767 
768 MODULE_DESCRIPTION("SuperH on-chip RTC driver");
769 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, "
770 	      "Jamie Lenehan <lenehan@twibble.org>, "
771 	      "Angelo Castello <angelo.castello@st.com>");
772 MODULE_LICENSE("GPL");
773 MODULE_ALIAS("platform:" DRV_NAME);
774