xref: /linux/drivers/rtc/rtc-sh.c (revision 856e7c4b619af622d56b3b454f7bec32a170ac99)
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/kernel.h>
19 #include <linux/bcd.h>
20 #include <linux/rtc.h>
21 #include <linux/init.h>
22 #include <linux/platform_device.h>
23 #include <linux/seq_file.h>
24 #include <linux/interrupt.h>
25 #include <linux/spinlock.h>
26 #include <linux/io.h>
27 #include <linux/log2.h>
28 #include <linux/clk.h>
29 #include <linux/slab.h>
30 #ifdef CONFIG_SUPERH
31 #include <asm/rtc.h>
32 #else
33 /* Default values for RZ/A RTC */
34 #define rtc_reg_size		sizeof(u16)
35 #define RTC_BIT_INVERTED        0	/* no chip bugs */
36 #define RTC_CAP_4_DIGIT_YEAR    (1 << 0)
37 #define RTC_DEF_CAPABILITIES    RTC_CAP_4_DIGIT_YEAR
38 #endif
39 
40 #define DRV_NAME	"sh-rtc"
41 
42 #define RTC_REG(r)	((r) * rtc_reg_size)
43 
44 #define R64CNT		RTC_REG(0)
45 
46 #define RSECCNT		RTC_REG(1)	/* RTC sec */
47 #define RMINCNT		RTC_REG(2)	/* RTC min */
48 #define RHRCNT		RTC_REG(3)	/* RTC hour */
49 #define RWKCNT		RTC_REG(4)	/* RTC week */
50 #define RDAYCNT		RTC_REG(5)	/* RTC day */
51 #define RMONCNT		RTC_REG(6)	/* RTC month */
52 #define RYRCNT		RTC_REG(7)	/* RTC year */
53 #define RSECAR		RTC_REG(8)	/* ALARM sec */
54 #define RMINAR		RTC_REG(9)	/* ALARM min */
55 #define RHRAR		RTC_REG(10)	/* ALARM hour */
56 #define RWKAR		RTC_REG(11)	/* ALARM week */
57 #define RDAYAR		RTC_REG(12)	/* ALARM day */
58 #define RMONAR		RTC_REG(13)	/* ALARM month */
59 #define RCR1		RTC_REG(14)	/* Control */
60 #define RCR2		RTC_REG(15)	/* Control */
61 
62 /*
63  * Note on RYRAR and RCR3: Up until this point most of the register
64  * definitions are consistent across all of the available parts. However,
65  * the placement of the optional RYRAR and RCR3 (the RYRAR control
66  * register used to control RYRCNT/RYRAR compare) varies considerably
67  * across various parts, occasionally being mapped in to a completely
68  * unrelated address space. For proper RYRAR support a separate resource
69  * would have to be handed off, but as this is purely optional in
70  * practice, we simply opt not to support it, thereby keeping the code
71  * quite a bit more simplified.
72  */
73 
74 /* ALARM Bits - or with BCD encoded value */
75 #define AR_ENB		0x80	/* Enable for alarm cmp   */
76 
77 /* Period Bits */
78 #define PF_HP		0x100	/* Enable Half Period to support 8,32,128Hz */
79 #define PF_COUNT	0x200	/* Half periodic counter */
80 #define PF_OXS		0x400	/* Periodic One x Second */
81 #define PF_KOU		0x800	/* Kernel or User periodic request 1=kernel */
82 #define PF_MASK		0xf00
83 
84 /* RCR1 Bits */
85 #define RCR1_CF		0x80	/* Carry Flag             */
86 #define RCR1_CIE	0x10	/* Carry Interrupt Enable */
87 #define RCR1_AIE	0x08	/* Alarm Interrupt Enable */
88 #define RCR1_AF		0x01	/* Alarm Flag             */
89 
90 /* RCR2 Bits */
91 #define RCR2_PEF	0x80	/* PEriodic interrupt Flag */
92 #define RCR2_PESMASK	0x70	/* Periodic interrupt Set  */
93 #define RCR2_RTCEN	0x08	/* ENable RTC              */
94 #define RCR2_ADJ	0x04	/* ADJustment (30-second)  */
95 #define RCR2_RESET	0x02	/* Reset bit               */
96 #define RCR2_START	0x01	/* Start bit               */
97 
98 struct sh_rtc {
99 	void __iomem		*regbase;
100 	unsigned long		regsize;
101 	struct resource		*res;
102 	int			alarm_irq;
103 	int			periodic_irq;
104 	int			carry_irq;
105 	struct clk		*clk;
106 	struct rtc_device	*rtc_dev;
107 	spinlock_t		lock;
108 	unsigned long		capabilities;	/* See asm/rtc.h for cap bits */
109 	unsigned short		periodic_freq;
110 };
111 
112 static int __sh_rtc_interrupt(struct sh_rtc *rtc)
113 {
114 	unsigned int tmp, pending;
115 
116 	tmp = readb(rtc->regbase + RCR1);
117 	pending = tmp & RCR1_CF;
118 	tmp &= ~RCR1_CF;
119 	writeb(tmp, rtc->regbase + RCR1);
120 
121 	/* Users have requested One x Second IRQ */
122 	if (pending && rtc->periodic_freq & PF_OXS)
123 		rtc_update_irq(rtc->rtc_dev, 1, RTC_UF | RTC_IRQF);
124 
125 	return pending;
126 }
127 
128 static int __sh_rtc_alarm(struct sh_rtc *rtc)
129 {
130 	unsigned int tmp, pending;
131 
132 	tmp = readb(rtc->regbase + RCR1);
133 	pending = tmp & RCR1_AF;
134 	tmp &= ~(RCR1_AF | RCR1_AIE);
135 	writeb(tmp, rtc->regbase + RCR1);
136 
137 	if (pending)
138 		rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
139 
140 	return pending;
141 }
142 
143 static int __sh_rtc_periodic(struct sh_rtc *rtc)
144 {
145 	struct rtc_device *rtc_dev = rtc->rtc_dev;
146 	struct rtc_task *irq_task;
147 	unsigned int tmp, pending;
148 
149 	tmp = readb(rtc->regbase + RCR2);
150 	pending = tmp & RCR2_PEF;
151 	tmp &= ~RCR2_PEF;
152 	writeb(tmp, rtc->regbase + RCR2);
153 
154 	if (!pending)
155 		return 0;
156 
157 	/* Half period enabled than one skipped and the next notified */
158 	if ((rtc->periodic_freq & PF_HP) && (rtc->periodic_freq & PF_COUNT))
159 		rtc->periodic_freq &= ~PF_COUNT;
160 	else {
161 		if (rtc->periodic_freq & PF_HP)
162 			rtc->periodic_freq |= PF_COUNT;
163 		if (rtc->periodic_freq & PF_KOU) {
164 			spin_lock(&rtc_dev->irq_task_lock);
165 			irq_task = rtc_dev->irq_task;
166 			if (irq_task)
167 				irq_task->func(irq_task->private_data);
168 			spin_unlock(&rtc_dev->irq_task_lock);
169 		} else
170 			rtc_update_irq(rtc->rtc_dev, 1, RTC_PF | RTC_IRQF);
171 	}
172 
173 	return pending;
174 }
175 
176 static irqreturn_t sh_rtc_interrupt(int irq, void *dev_id)
177 {
178 	struct sh_rtc *rtc = dev_id;
179 	int ret;
180 
181 	spin_lock(&rtc->lock);
182 	ret = __sh_rtc_interrupt(rtc);
183 	spin_unlock(&rtc->lock);
184 
185 	return IRQ_RETVAL(ret);
186 }
187 
188 static irqreturn_t sh_rtc_alarm(int irq, void *dev_id)
189 {
190 	struct sh_rtc *rtc = dev_id;
191 	int ret;
192 
193 	spin_lock(&rtc->lock);
194 	ret = __sh_rtc_alarm(rtc);
195 	spin_unlock(&rtc->lock);
196 
197 	return IRQ_RETVAL(ret);
198 }
199 
200 static irqreturn_t sh_rtc_periodic(int irq, void *dev_id)
201 {
202 	struct sh_rtc *rtc = dev_id;
203 	int ret;
204 
205 	spin_lock(&rtc->lock);
206 	ret = __sh_rtc_periodic(rtc);
207 	spin_unlock(&rtc->lock);
208 
209 	return IRQ_RETVAL(ret);
210 }
211 
212 static irqreturn_t sh_rtc_shared(int irq, void *dev_id)
213 {
214 	struct sh_rtc *rtc = dev_id;
215 	int ret;
216 
217 	spin_lock(&rtc->lock);
218 	ret = __sh_rtc_interrupt(rtc);
219 	ret |= __sh_rtc_alarm(rtc);
220 	ret |= __sh_rtc_periodic(rtc);
221 	spin_unlock(&rtc->lock);
222 
223 	return IRQ_RETVAL(ret);
224 }
225 
226 static int sh_rtc_irq_set_state(struct device *dev, int enable)
227 {
228 	struct sh_rtc *rtc = dev_get_drvdata(dev);
229 	unsigned int tmp;
230 
231 	spin_lock_irq(&rtc->lock);
232 
233 	tmp = readb(rtc->regbase + RCR2);
234 
235 	if (enable) {
236 		rtc->periodic_freq |= PF_KOU;
237 		tmp &= ~RCR2_PEF;	/* Clear PES bit */
238 		tmp |= (rtc->periodic_freq & ~PF_HP);	/* Set PES2-0 */
239 	} else {
240 		rtc->periodic_freq &= ~PF_KOU;
241 		tmp &= ~(RCR2_PESMASK | RCR2_PEF);
242 	}
243 
244 	writeb(tmp, rtc->regbase + RCR2);
245 
246 	spin_unlock_irq(&rtc->lock);
247 
248 	return 0;
249 }
250 
251 static int sh_rtc_irq_set_freq(struct device *dev, int freq)
252 {
253 	struct sh_rtc *rtc = dev_get_drvdata(dev);
254 	int tmp, ret = 0;
255 
256 	spin_lock_irq(&rtc->lock);
257 	tmp = rtc->periodic_freq & PF_MASK;
258 
259 	switch (freq) {
260 	case 0:
261 		rtc->periodic_freq = 0x00;
262 		break;
263 	case 1:
264 		rtc->periodic_freq = 0x60;
265 		break;
266 	case 2:
267 		rtc->periodic_freq = 0x50;
268 		break;
269 	case 4:
270 		rtc->periodic_freq = 0x40;
271 		break;
272 	case 8:
273 		rtc->periodic_freq = 0x30 | PF_HP;
274 		break;
275 	case 16:
276 		rtc->periodic_freq = 0x30;
277 		break;
278 	case 32:
279 		rtc->periodic_freq = 0x20 | PF_HP;
280 		break;
281 	case 64:
282 		rtc->periodic_freq = 0x20;
283 		break;
284 	case 128:
285 		rtc->periodic_freq = 0x10 | PF_HP;
286 		break;
287 	case 256:
288 		rtc->periodic_freq = 0x10;
289 		break;
290 	default:
291 		ret = -ENOTSUPP;
292 	}
293 
294 	if (ret == 0)
295 		rtc->periodic_freq |= tmp;
296 
297 	spin_unlock_irq(&rtc->lock);
298 	return ret;
299 }
300 
301 static inline void sh_rtc_setaie(struct device *dev, unsigned int enable)
302 {
303 	struct sh_rtc *rtc = dev_get_drvdata(dev);
304 	unsigned int tmp;
305 
306 	spin_lock_irq(&rtc->lock);
307 
308 	tmp = readb(rtc->regbase + RCR1);
309 
310 	if (enable)
311 		tmp |= RCR1_AIE;
312 	else
313 		tmp &= ~RCR1_AIE;
314 
315 	writeb(tmp, rtc->regbase + RCR1);
316 
317 	spin_unlock_irq(&rtc->lock);
318 }
319 
320 static int sh_rtc_proc(struct device *dev, struct seq_file *seq)
321 {
322 	struct sh_rtc *rtc = dev_get_drvdata(dev);
323 	unsigned int tmp;
324 
325 	tmp = readb(rtc->regbase + RCR1);
326 	seq_printf(seq, "carry_IRQ\t: %s\n", (tmp & RCR1_CIE) ? "yes" : "no");
327 
328 	tmp = readb(rtc->regbase + RCR2);
329 	seq_printf(seq, "periodic_IRQ\t: %s\n",
330 		   (tmp & RCR2_PESMASK) ? "yes" : "no");
331 
332 	return 0;
333 }
334 
335 static inline void sh_rtc_setcie(struct device *dev, unsigned int enable)
336 {
337 	struct sh_rtc *rtc = dev_get_drvdata(dev);
338 	unsigned int tmp;
339 
340 	spin_lock_irq(&rtc->lock);
341 
342 	tmp = readb(rtc->regbase + RCR1);
343 
344 	if (!enable)
345 		tmp &= ~RCR1_CIE;
346 	else
347 		tmp |= RCR1_CIE;
348 
349 	writeb(tmp, rtc->regbase + RCR1);
350 
351 	spin_unlock_irq(&rtc->lock);
352 }
353 
354 static int sh_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
355 {
356 	sh_rtc_setaie(dev, enabled);
357 	return 0;
358 }
359 
360 static int sh_rtc_read_time(struct device *dev, struct rtc_time *tm)
361 {
362 	struct sh_rtc *rtc = dev_get_drvdata(dev);
363 	unsigned int sec128, sec2, yr, yr100, cf_bit;
364 
365 	do {
366 		unsigned int tmp;
367 
368 		spin_lock_irq(&rtc->lock);
369 
370 		tmp = readb(rtc->regbase + RCR1);
371 		tmp &= ~RCR1_CF; /* Clear CF-bit */
372 		tmp |= RCR1_CIE;
373 		writeb(tmp, rtc->regbase + RCR1);
374 
375 		sec128 = readb(rtc->regbase + R64CNT);
376 
377 		tm->tm_sec	= bcd2bin(readb(rtc->regbase + RSECCNT));
378 		tm->tm_min	= bcd2bin(readb(rtc->regbase + RMINCNT));
379 		tm->tm_hour	= bcd2bin(readb(rtc->regbase + RHRCNT));
380 		tm->tm_wday	= bcd2bin(readb(rtc->regbase + RWKCNT));
381 		tm->tm_mday	= bcd2bin(readb(rtc->regbase + RDAYCNT));
382 		tm->tm_mon	= bcd2bin(readb(rtc->regbase + RMONCNT)) - 1;
383 
384 		if (rtc->capabilities & RTC_CAP_4_DIGIT_YEAR) {
385 			yr  = readw(rtc->regbase + RYRCNT);
386 			yr100 = bcd2bin(yr >> 8);
387 			yr &= 0xff;
388 		} else {
389 			yr  = readb(rtc->regbase + RYRCNT);
390 			yr100 = bcd2bin((yr == 0x99) ? 0x19 : 0x20);
391 		}
392 
393 		tm->tm_year = (yr100 * 100 + bcd2bin(yr)) - 1900;
394 
395 		sec2 = readb(rtc->regbase + R64CNT);
396 		cf_bit = readb(rtc->regbase + RCR1) & RCR1_CF;
397 
398 		spin_unlock_irq(&rtc->lock);
399 	} while (cf_bit != 0 || ((sec128 ^ sec2) & RTC_BIT_INVERTED) != 0);
400 
401 #if RTC_BIT_INVERTED != 0
402 	if ((sec128 & RTC_BIT_INVERTED))
403 		tm->tm_sec--;
404 #endif
405 
406 	/* only keep the carry interrupt enabled if UIE is on */
407 	if (!(rtc->periodic_freq & PF_OXS))
408 		sh_rtc_setcie(dev, 0);
409 
410 	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
411 		"mday=%d, mon=%d, year=%d, wday=%d\n",
412 		__func__,
413 		tm->tm_sec, tm->tm_min, tm->tm_hour,
414 		tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday);
415 
416 	return 0;
417 }
418 
419 static int sh_rtc_set_time(struct device *dev, struct rtc_time *tm)
420 {
421 	struct sh_rtc *rtc = dev_get_drvdata(dev);
422 	unsigned int tmp;
423 	int year;
424 
425 	spin_lock_irq(&rtc->lock);
426 
427 	/* Reset pre-scaler & stop RTC */
428 	tmp = readb(rtc->regbase + RCR2);
429 	tmp |= RCR2_RESET;
430 	tmp &= ~RCR2_START;
431 	writeb(tmp, rtc->regbase + RCR2);
432 
433 	writeb(bin2bcd(tm->tm_sec),  rtc->regbase + RSECCNT);
434 	writeb(bin2bcd(tm->tm_min),  rtc->regbase + RMINCNT);
435 	writeb(bin2bcd(tm->tm_hour), rtc->regbase + RHRCNT);
436 	writeb(bin2bcd(tm->tm_wday), rtc->regbase + RWKCNT);
437 	writeb(bin2bcd(tm->tm_mday), rtc->regbase + RDAYCNT);
438 	writeb(bin2bcd(tm->tm_mon + 1), rtc->regbase + RMONCNT);
439 
440 	if (rtc->capabilities & RTC_CAP_4_DIGIT_YEAR) {
441 		year = (bin2bcd((tm->tm_year + 1900) / 100) << 8) |
442 			bin2bcd(tm->tm_year % 100);
443 		writew(year, rtc->regbase + RYRCNT);
444 	} else {
445 		year = tm->tm_year % 100;
446 		writeb(bin2bcd(year), rtc->regbase + RYRCNT);
447 	}
448 
449 	/* Start RTC */
450 	tmp = readb(rtc->regbase + RCR2);
451 	tmp &= ~RCR2_RESET;
452 	tmp |= RCR2_RTCEN | RCR2_START;
453 	writeb(tmp, rtc->regbase + RCR2);
454 
455 	spin_unlock_irq(&rtc->lock);
456 
457 	return 0;
458 }
459 
460 static inline int sh_rtc_read_alarm_value(struct sh_rtc *rtc, int reg_off)
461 {
462 	unsigned int byte;
463 	int value = 0xff;	/* return 0xff for ignored values */
464 
465 	byte = readb(rtc->regbase + reg_off);
466 	if (byte & AR_ENB) {
467 		byte &= ~AR_ENB;	/* strip the enable bit */
468 		value = bcd2bin(byte);
469 	}
470 
471 	return value;
472 }
473 
474 static int sh_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
475 {
476 	struct sh_rtc *rtc = dev_get_drvdata(dev);
477 	struct rtc_time *tm = &wkalrm->time;
478 
479 	spin_lock_irq(&rtc->lock);
480 
481 	tm->tm_sec	= sh_rtc_read_alarm_value(rtc, RSECAR);
482 	tm->tm_min	= sh_rtc_read_alarm_value(rtc, RMINAR);
483 	tm->tm_hour	= sh_rtc_read_alarm_value(rtc, RHRAR);
484 	tm->tm_wday	= sh_rtc_read_alarm_value(rtc, RWKAR);
485 	tm->tm_mday	= sh_rtc_read_alarm_value(rtc, RDAYAR);
486 	tm->tm_mon	= sh_rtc_read_alarm_value(rtc, RMONAR);
487 	if (tm->tm_mon > 0)
488 		tm->tm_mon -= 1; /* RTC is 1-12, tm_mon is 0-11 */
489 
490 	wkalrm->enabled = (readb(rtc->regbase + RCR1) & RCR1_AIE) ? 1 : 0;
491 
492 	spin_unlock_irq(&rtc->lock);
493 
494 	return 0;
495 }
496 
497 static inline void sh_rtc_write_alarm_value(struct sh_rtc *rtc,
498 					    int value, int reg_off)
499 {
500 	/* < 0 for a value that is ignored */
501 	if (value < 0)
502 		writeb(0, rtc->regbase + reg_off);
503 	else
504 		writeb(bin2bcd(value) | AR_ENB,  rtc->regbase + reg_off);
505 }
506 
507 static int sh_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
508 {
509 	struct sh_rtc *rtc = dev_get_drvdata(dev);
510 	unsigned int rcr1;
511 	struct rtc_time *tm = &wkalrm->time;
512 	int mon;
513 
514 	spin_lock_irq(&rtc->lock);
515 
516 	/* disable alarm interrupt and clear the alarm flag */
517 	rcr1 = readb(rtc->regbase + RCR1);
518 	rcr1 &= ~(RCR1_AF | RCR1_AIE);
519 	writeb(rcr1, rtc->regbase + RCR1);
520 
521 	/* set alarm time */
522 	sh_rtc_write_alarm_value(rtc, tm->tm_sec,  RSECAR);
523 	sh_rtc_write_alarm_value(rtc, tm->tm_min,  RMINAR);
524 	sh_rtc_write_alarm_value(rtc, tm->tm_hour, RHRAR);
525 	sh_rtc_write_alarm_value(rtc, tm->tm_wday, RWKAR);
526 	sh_rtc_write_alarm_value(rtc, tm->tm_mday, RDAYAR);
527 	mon = tm->tm_mon;
528 	if (mon >= 0)
529 		mon += 1;
530 	sh_rtc_write_alarm_value(rtc, mon, RMONAR);
531 
532 	if (wkalrm->enabled) {
533 		rcr1 |= RCR1_AIE;
534 		writeb(rcr1, rtc->regbase + RCR1);
535 	}
536 
537 	spin_unlock_irq(&rtc->lock);
538 
539 	return 0;
540 }
541 
542 static const struct rtc_class_ops sh_rtc_ops = {
543 	.read_time	= sh_rtc_read_time,
544 	.set_time	= sh_rtc_set_time,
545 	.read_alarm	= sh_rtc_read_alarm,
546 	.set_alarm	= sh_rtc_set_alarm,
547 	.proc		= sh_rtc_proc,
548 	.alarm_irq_enable = sh_rtc_alarm_irq_enable,
549 };
550 
551 static int __init sh_rtc_probe(struct platform_device *pdev)
552 {
553 	struct sh_rtc *rtc;
554 	struct resource *res;
555 	struct rtc_time r;
556 	char clk_name[6];
557 	int clk_id, ret;
558 
559 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
560 	if (unlikely(!rtc))
561 		return -ENOMEM;
562 
563 	spin_lock_init(&rtc->lock);
564 
565 	/* get periodic/carry/alarm irqs */
566 	ret = platform_get_irq(pdev, 0);
567 	if (unlikely(ret <= 0)) {
568 		dev_err(&pdev->dev, "No IRQ resource\n");
569 		return -ENOENT;
570 	}
571 
572 	rtc->periodic_irq = ret;
573 	rtc->carry_irq = platform_get_irq(pdev, 1);
574 	rtc->alarm_irq = platform_get_irq(pdev, 2);
575 
576 	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
577 	if (!res)
578 		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
579 	if (unlikely(res == NULL)) {
580 		dev_err(&pdev->dev, "No IO resource\n");
581 		return -ENOENT;
582 	}
583 
584 	rtc->regsize = resource_size(res);
585 
586 	rtc->res = devm_request_mem_region(&pdev->dev, res->start,
587 					rtc->regsize, pdev->name);
588 	if (unlikely(!rtc->res))
589 		return -EBUSY;
590 
591 	rtc->regbase = devm_ioremap_nocache(&pdev->dev, rtc->res->start,
592 					rtc->regsize);
593 	if (unlikely(!rtc->regbase))
594 		return -EINVAL;
595 
596 	if (!pdev->dev.of_node) {
597 		clk_id = pdev->id;
598 		/* With a single device, the clock id is still "rtc0" */
599 		if (clk_id < 0)
600 			clk_id = 0;
601 
602 		snprintf(clk_name, sizeof(clk_name), "rtc%d", clk_id);
603 	} else
604 		snprintf(clk_name, sizeof(clk_name), "fck");
605 
606 	rtc->clk = devm_clk_get(&pdev->dev, clk_name);
607 	if (IS_ERR(rtc->clk)) {
608 		/*
609 		 * No error handling for rtc->clk intentionally, not all
610 		 * platforms will have a unique clock for the RTC, and
611 		 * the clk API can handle the struct clk pointer being
612 		 * NULL.
613 		 */
614 		rtc->clk = NULL;
615 	}
616 
617 	clk_enable(rtc->clk);
618 
619 	rtc->capabilities = RTC_DEF_CAPABILITIES;
620 
621 #ifdef CONFIG_SUPERH
622 	if (dev_get_platdata(&pdev->dev)) {
623 		struct sh_rtc_platform_info *pinfo =
624 			dev_get_platdata(&pdev->dev);
625 
626 		/*
627 		 * Some CPUs have special capabilities in addition to the
628 		 * default set. Add those in here.
629 		 */
630 		rtc->capabilities |= pinfo->capabilities;
631 	}
632 #endif
633 
634 	if (rtc->carry_irq <= 0) {
635 		/* register shared periodic/carry/alarm irq */
636 		ret = devm_request_irq(&pdev->dev, rtc->periodic_irq,
637 				sh_rtc_shared, 0, "sh-rtc", rtc);
638 		if (unlikely(ret)) {
639 			dev_err(&pdev->dev,
640 				"request IRQ failed with %d, IRQ %d\n", ret,
641 				rtc->periodic_irq);
642 			goto err_unmap;
643 		}
644 	} else {
645 		/* register periodic/carry/alarm irqs */
646 		ret = devm_request_irq(&pdev->dev, rtc->periodic_irq,
647 				sh_rtc_periodic, 0, "sh-rtc period", rtc);
648 		if (unlikely(ret)) {
649 			dev_err(&pdev->dev,
650 				"request period IRQ failed with %d, IRQ %d\n",
651 				ret, rtc->periodic_irq);
652 			goto err_unmap;
653 		}
654 
655 		ret = devm_request_irq(&pdev->dev, rtc->carry_irq,
656 				sh_rtc_interrupt, 0, "sh-rtc carry", rtc);
657 		if (unlikely(ret)) {
658 			dev_err(&pdev->dev,
659 				"request carry IRQ failed with %d, IRQ %d\n",
660 				ret, rtc->carry_irq);
661 			goto err_unmap;
662 		}
663 
664 		ret = devm_request_irq(&pdev->dev, rtc->alarm_irq,
665 				sh_rtc_alarm, 0, "sh-rtc alarm", rtc);
666 		if (unlikely(ret)) {
667 			dev_err(&pdev->dev,
668 				"request alarm IRQ failed with %d, IRQ %d\n",
669 				ret, rtc->alarm_irq);
670 			goto err_unmap;
671 		}
672 	}
673 
674 	platform_set_drvdata(pdev, rtc);
675 
676 	/* everything disabled by default */
677 	sh_rtc_irq_set_freq(&pdev->dev, 0);
678 	sh_rtc_irq_set_state(&pdev->dev, 0);
679 	sh_rtc_setaie(&pdev->dev, 0);
680 	sh_rtc_setcie(&pdev->dev, 0);
681 
682 	rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "sh",
683 					   &sh_rtc_ops, THIS_MODULE);
684 	if (IS_ERR(rtc->rtc_dev)) {
685 		ret = PTR_ERR(rtc->rtc_dev);
686 		goto err_unmap;
687 	}
688 
689 	rtc->rtc_dev->max_user_freq = 256;
690 
691 	/* reset rtc to epoch 0 if time is invalid */
692 	if (rtc_read_time(rtc->rtc_dev, &r) < 0) {
693 		rtc_time_to_tm(0, &r);
694 		rtc_set_time(rtc->rtc_dev, &r);
695 	}
696 
697 	device_init_wakeup(&pdev->dev, 1);
698 	return 0;
699 
700 err_unmap:
701 	clk_disable(rtc->clk);
702 
703 	return ret;
704 }
705 
706 static int __exit sh_rtc_remove(struct platform_device *pdev)
707 {
708 	struct sh_rtc *rtc = platform_get_drvdata(pdev);
709 
710 	sh_rtc_irq_set_state(&pdev->dev, 0);
711 
712 	sh_rtc_setaie(&pdev->dev, 0);
713 	sh_rtc_setcie(&pdev->dev, 0);
714 
715 	clk_disable(rtc->clk);
716 
717 	return 0;
718 }
719 
720 static void sh_rtc_set_irq_wake(struct device *dev, int enabled)
721 {
722 	struct sh_rtc *rtc = dev_get_drvdata(dev);
723 
724 	irq_set_irq_wake(rtc->periodic_irq, enabled);
725 
726 	if (rtc->carry_irq > 0) {
727 		irq_set_irq_wake(rtc->carry_irq, enabled);
728 		irq_set_irq_wake(rtc->alarm_irq, enabled);
729 	}
730 }
731 
732 static int __maybe_unused sh_rtc_suspend(struct device *dev)
733 {
734 	if (device_may_wakeup(dev))
735 		sh_rtc_set_irq_wake(dev, 1);
736 
737 	return 0;
738 }
739 
740 static int __maybe_unused sh_rtc_resume(struct device *dev)
741 {
742 	if (device_may_wakeup(dev))
743 		sh_rtc_set_irq_wake(dev, 0);
744 
745 	return 0;
746 }
747 
748 static SIMPLE_DEV_PM_OPS(sh_rtc_pm_ops, sh_rtc_suspend, sh_rtc_resume);
749 
750 static const struct of_device_id sh_rtc_of_match[] = {
751 	{ .compatible = "renesas,sh-rtc", },
752 	{ /* sentinel */ }
753 };
754 MODULE_DEVICE_TABLE(of, sh_rtc_of_match);
755 
756 static struct platform_driver sh_rtc_platform_driver = {
757 	.driver		= {
758 		.name	= DRV_NAME,
759 		.pm	= &sh_rtc_pm_ops,
760 		.of_match_table = sh_rtc_of_match,
761 	},
762 	.remove		= __exit_p(sh_rtc_remove),
763 };
764 
765 module_platform_driver_probe(sh_rtc_platform_driver, sh_rtc_probe);
766 
767 MODULE_DESCRIPTION("SuperH on-chip RTC driver");
768 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, "
769 	      "Jamie Lenehan <lenehan@twibble.org>, "
770 	      "Angelo Castello <angelo.castello@st.com>");
771 MODULE_LICENSE("GPL");
772 MODULE_ALIAS("platform:" DRV_NAME);
773