xref: /linux/drivers/rtc/rtc-cmos.c (revision ba6e8564f459211117ce300eae2c7fdd23befe34)
1 /*
2  * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
3  *
4  * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
5  * Copyright (C) 2006 David Brownell (convert to new framework)
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
9  * as published by the Free Software Foundation; either version
10  * 2 of the License, or (at your option) any later version.
11  */
12 
13 /*
14  * The original "cmos clock" chip was an MC146818 chip, now obsolete.
15  * That defined the register interface now provided by all PCs, some
16  * non-PC systems, and incorporated into ACPI.  Modern PC chipsets
17  * integrate an MC146818 clone in their southbridge, and boards use
18  * that instead of discrete clones like the DS12887 or M48T86.  There
19  * are also clones that connect using the LPC bus.
20  *
21  * That register API is also used directly by various other drivers
22  * (notably for integrated NVRAM), infrastructure (x86 has code to
23  * bypass the RTC framework, directly reading the RTC during boot
24  * and updating minutes/seconds for systems using NTP synch) and
25  * utilities (like userspace 'hwclock', if no /dev node exists).
26  *
27  * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
28  * interrupts disabled, holding the global rtc_lock, to exclude those
29  * other drivers and utilities on correctly configured systems.
30  */
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/init.h>
34 #include <linux/interrupt.h>
35 #include <linux/spinlock.h>
36 #include <linux/platform_device.h>
37 #include <linux/mod_devicetable.h>
38 
39 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
40 #include <asm-generic/rtc.h>
41 
42 
43 struct cmos_rtc {
44 	struct rtc_device	*rtc;
45 	struct device		*dev;
46 	int			irq;
47 	struct resource		*iomem;
48 
49 	u8			suspend_ctrl;
50 
51 	/* newer hardware extends the original register set */
52 	u8			day_alrm;
53 	u8			mon_alrm;
54 	u8			century;
55 };
56 
57 /* both platform and pnp busses use negative numbers for invalid irqs */
58 #define is_valid_irq(n)		((n) >= 0)
59 
60 static const char driver_name[] = "rtc_cmos";
61 
62 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
63  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
64  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
65  */
66 #define	RTC_IRQMASK	(RTC_PF | RTC_AF | RTC_UF)
67 
68 static inline int is_intr(u8 rtc_intr)
69 {
70 	if (!(rtc_intr & RTC_IRQF))
71 		return 0;
72 	return rtc_intr & RTC_IRQMASK;
73 }
74 
75 /*----------------------------------------------------------------*/
76 
77 static int cmos_read_time(struct device *dev, struct rtc_time *t)
78 {
79 	/* REVISIT:  if the clock has a "century" register, use
80 	 * that instead of the heuristic in get_rtc_time().
81 	 * That'll make Y3K compatility (year > 2070) easy!
82 	 */
83 	get_rtc_time(t);
84 	return 0;
85 }
86 
87 static int cmos_set_time(struct device *dev, struct rtc_time *t)
88 {
89 	/* REVISIT:  set the "century" register if available
90 	 *
91 	 * NOTE: this ignores the issue whereby updating the seconds
92 	 * takes effect exactly 500ms after we write the register.
93 	 * (Also queueing and other delays before we get this far.)
94 	 */
95 	return set_rtc_time(t);
96 }
97 
98 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
99 {
100 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
101 	unsigned char	rtc_control;
102 
103 	if (!is_valid_irq(cmos->irq))
104 		return -EIO;
105 
106 	/* Basic alarms only support hour, minute, and seconds fields.
107 	 * Some also support day and month, for alarms up to a year in
108 	 * the future.
109 	 */
110 	t->time.tm_mday = -1;
111 	t->time.tm_mon = -1;
112 
113 	spin_lock_irq(&rtc_lock);
114 	t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
115 	t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
116 	t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
117 
118 	if (cmos->day_alrm) {
119 		t->time.tm_mday = CMOS_READ(cmos->day_alrm);
120 		if (!t->time.tm_mday)
121 			t->time.tm_mday = -1;
122 
123 		if (cmos->mon_alrm) {
124 			t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
125 			if (!t->time.tm_mon)
126 				t->time.tm_mon = -1;
127 		}
128 	}
129 
130 	rtc_control = CMOS_READ(RTC_CONTROL);
131 	spin_unlock_irq(&rtc_lock);
132 
133 	/* REVISIT this assumes PC style usage:  always BCD */
134 
135 	if (((unsigned)t->time.tm_sec) < 0x60)
136 		t->time.tm_sec = BCD2BIN(t->time.tm_sec);
137 	else
138 		t->time.tm_sec = -1;
139 	if (((unsigned)t->time.tm_min) < 0x60)
140 		t->time.tm_min = BCD2BIN(t->time.tm_min);
141 	else
142 		t->time.tm_min = -1;
143 	if (((unsigned)t->time.tm_hour) < 0x24)
144 		t->time.tm_hour = BCD2BIN(t->time.tm_hour);
145 	else
146 		t->time.tm_hour = -1;
147 
148 	if (cmos->day_alrm) {
149 		if (((unsigned)t->time.tm_mday) <= 0x31)
150 			t->time.tm_mday = BCD2BIN(t->time.tm_mday);
151 		else
152 			t->time.tm_mday = -1;
153 		if (cmos->mon_alrm) {
154 			if (((unsigned)t->time.tm_mon) <= 0x12)
155 				t->time.tm_mon = BCD2BIN(t->time.tm_mon) - 1;
156 			else
157 				t->time.tm_mon = -1;
158 		}
159 	}
160 	t->time.tm_year = -1;
161 
162 	t->enabled = !!(rtc_control & RTC_AIE);
163 	t->pending = 0;
164 
165 	return 0;
166 }
167 
168 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
169 {
170 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
171 	unsigned char	mon, mday, hrs, min, sec;
172 	unsigned char	rtc_control, rtc_intr;
173 
174 	if (!is_valid_irq(cmos->irq))
175 		return -EIO;
176 
177 	/* REVISIT this assumes PC style usage:  always BCD */
178 
179 	/* Writing 0xff means "don't care" or "match all".  */
180 
181 	mon = t->time.tm_mon;
182 	mon = (mon < 12) ? BIN2BCD(mon) : 0xff;
183 	mon++;
184 
185 	mday = t->time.tm_mday;
186 	mday = (mday >= 1 && mday <= 31) ? BIN2BCD(mday) : 0xff;
187 
188 	hrs = t->time.tm_hour;
189 	hrs = (hrs < 24) ? BIN2BCD(hrs) : 0xff;
190 
191 	min = t->time.tm_min;
192 	min = (min < 60) ? BIN2BCD(min) : 0xff;
193 
194 	sec = t->time.tm_sec;
195 	sec = (sec < 60) ? BIN2BCD(sec) : 0xff;
196 
197 	spin_lock_irq(&rtc_lock);
198 
199 	/* next rtc irq must not be from previous alarm setting */
200 	rtc_control = CMOS_READ(RTC_CONTROL);
201 	rtc_control &= ~RTC_AIE;
202 	CMOS_WRITE(rtc_control, RTC_CONTROL);
203 	rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
204 	rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
205 	if (is_intr(rtc_intr))
206 		rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);
207 
208 	/* update alarm */
209 	CMOS_WRITE(hrs, RTC_HOURS_ALARM);
210 	CMOS_WRITE(min, RTC_MINUTES_ALARM);
211 	CMOS_WRITE(sec, RTC_SECONDS_ALARM);
212 
213 	/* the system may support an "enhanced" alarm */
214 	if (cmos->day_alrm) {
215 		CMOS_WRITE(mday, cmos->day_alrm);
216 		if (cmos->mon_alrm)
217 			CMOS_WRITE(mon, cmos->mon_alrm);
218 	}
219 
220 	if (t->enabled) {
221 		rtc_control |= RTC_AIE;
222 		CMOS_WRITE(rtc_control, RTC_CONTROL);
223 		rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
224 		rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
225 		if (is_intr(rtc_intr))
226 			rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);
227 	}
228 
229 	spin_unlock_irq(&rtc_lock);
230 
231 	return 0;
232 }
233 
234 static int cmos_set_freq(struct device *dev, int freq)
235 {
236 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
237 	int		f;
238 	unsigned long	flags;
239 
240 	if (!is_valid_irq(cmos->irq))
241 		return -ENXIO;
242 
243 	/* 0 = no irqs; 1 = 2^15 Hz ... 15 = 2^0 Hz */
244 	f = ffs(freq);
245 	if (f != 0) {
246 		if (f-- > 16 || freq != (1 << f))
247 			return -EINVAL;
248 		f = 16 - f;
249 	}
250 
251 	spin_lock_irqsave(&rtc_lock, flags);
252 	CMOS_WRITE(RTC_REF_CLCK_32KHZ | f, RTC_FREQ_SELECT);
253 	spin_unlock_irqrestore(&rtc_lock, flags);
254 
255 	return 0;
256 }
257 
258 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
259 
260 static int
261 cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
262 {
263 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
264 	unsigned char	rtc_control, rtc_intr;
265 	unsigned long	flags;
266 
267 	switch (cmd) {
268 	case RTC_AIE_OFF:
269 	case RTC_AIE_ON:
270 	case RTC_UIE_OFF:
271 	case RTC_UIE_ON:
272 	case RTC_PIE_OFF:
273 	case RTC_PIE_ON:
274 		if (!is_valid_irq(cmos->irq))
275 			return -EINVAL;
276 		break;
277 	default:
278 		return -ENOIOCTLCMD;
279 	}
280 
281 	spin_lock_irqsave(&rtc_lock, flags);
282 	rtc_control = CMOS_READ(RTC_CONTROL);
283 	switch (cmd) {
284 	case RTC_AIE_OFF:	/* alarm off */
285 		rtc_control &= ~RTC_AIE;
286 		break;
287 	case RTC_AIE_ON:	/* alarm on */
288 		rtc_control |= RTC_AIE;
289 		break;
290 	case RTC_UIE_OFF:	/* update off */
291 		rtc_control &= ~RTC_UIE;
292 		break;
293 	case RTC_UIE_ON:	/* update on */
294 		rtc_control |= RTC_UIE;
295 		break;
296 	case RTC_PIE_OFF:	/* periodic off */
297 		rtc_control &= ~RTC_PIE;
298 		break;
299 	case RTC_PIE_ON:	/* periodic on */
300 		rtc_control |= RTC_PIE;
301 		break;
302 	}
303 	CMOS_WRITE(rtc_control, RTC_CONTROL);
304 	rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
305 	rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
306 	if (is_intr(rtc_intr))
307 		rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);
308 	spin_unlock_irqrestore(&rtc_lock, flags);
309 	return 0;
310 }
311 
312 #else
313 #define	cmos_rtc_ioctl	NULL
314 #endif
315 
316 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
317 
318 static int cmos_procfs(struct device *dev, struct seq_file *seq)
319 {
320 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
321 	unsigned char	rtc_control, valid;
322 
323 	spin_lock_irq(&rtc_lock);
324 	rtc_control = CMOS_READ(RTC_CONTROL);
325 	valid = CMOS_READ(RTC_VALID);
326 	spin_unlock_irq(&rtc_lock);
327 
328 	/* NOTE:  at least ICH6 reports battery status using a different
329 	 * (non-RTC) bit; and SQWE is ignored on many current systems.
330 	 */
331 	return seq_printf(seq,
332 			"periodic_IRQ\t: %s\n"
333 			"update_IRQ\t: %s\n"
334 			// "square_wave\t: %s\n"
335 			// "BCD\t\t: %s\n"
336 			"DST_enable\t: %s\n"
337 			"periodic_freq\t: %d\n"
338 			"batt_status\t: %s\n",
339 			(rtc_control & RTC_PIE) ? "yes" : "no",
340 			(rtc_control & RTC_UIE) ? "yes" : "no",
341 			// (rtc_control & RTC_SQWE) ? "yes" : "no",
342 			// (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
343 			(rtc_control & RTC_DST_EN) ? "yes" : "no",
344 			cmos->rtc->irq_freq,
345 			(valid & RTC_VRT) ? "okay" : "dead");
346 }
347 
348 #else
349 #define	cmos_procfs	NULL
350 #endif
351 
352 static const struct rtc_class_ops cmos_rtc_ops = {
353 	.ioctl		= cmos_rtc_ioctl,
354 	.read_time	= cmos_read_time,
355 	.set_time	= cmos_set_time,
356 	.read_alarm	= cmos_read_alarm,
357 	.set_alarm	= cmos_set_alarm,
358 	.proc		= cmos_procfs,
359 	.irq_set_freq	= cmos_set_freq,
360 };
361 
362 /*----------------------------------------------------------------*/
363 
364 static struct cmos_rtc	cmos_rtc;
365 
366 static irqreturn_t cmos_interrupt(int irq, void *p)
367 {
368 	u8		irqstat;
369 
370 	spin_lock(&rtc_lock);
371 	irqstat = CMOS_READ(RTC_INTR_FLAGS);
372 	irqstat &= (CMOS_READ(RTC_CONTROL) & RTC_IRQMASK) | RTC_IRQF;
373 	spin_unlock(&rtc_lock);
374 
375 	if (is_intr(irqstat)) {
376 		rtc_update_irq(p, 1, irqstat);
377 		return IRQ_HANDLED;
378 	} else
379 		return IRQ_NONE;
380 }
381 
382 #ifdef	CONFIG_PNPACPI
383 #define	is_pnpacpi()	1
384 #define	INITSECTION
385 
386 #else
387 #define	is_pnpacpi()	0
388 #define	INITSECTION	__init
389 #endif
390 
391 static int INITSECTION
392 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
393 {
394 	struct cmos_rtc_board_info	*info = dev->platform_data;
395 	int				retval = 0;
396 	unsigned char			rtc_control;
397 
398 	/* there can be only one ... */
399 	if (cmos_rtc.dev)
400 		return -EBUSY;
401 
402 	if (!ports)
403 		return -ENODEV;
404 
405 	cmos_rtc.irq = rtc_irq;
406 	cmos_rtc.iomem = ports;
407 
408 	/* For ACPI systems the info comes from the FADT.  On others,
409 	 * board specific setup provides it as appropriate.
410 	 */
411 	if (info) {
412 		cmos_rtc.day_alrm = info->rtc_day_alarm;
413 		cmos_rtc.mon_alrm = info->rtc_mon_alarm;
414 		cmos_rtc.century = info->rtc_century;
415 	}
416 
417 	cmos_rtc.rtc = rtc_device_register(driver_name, dev,
418 				&cmos_rtc_ops, THIS_MODULE);
419 	if (IS_ERR(cmos_rtc.rtc))
420 		return PTR_ERR(cmos_rtc.rtc);
421 
422 	cmos_rtc.dev = dev;
423 	dev_set_drvdata(dev, &cmos_rtc);
424 
425 	/* platform and pnp busses handle resources incompatibly.
426 	 *
427 	 * REVISIT for non-x86 systems we may need to handle io memory
428 	 * resources: ioremap them, and request_mem_region().
429 	 */
430 	if (is_pnpacpi()) {
431 		retval = request_resource(&ioport_resource, ports);
432 		if (retval < 0) {
433 			dev_dbg(dev, "i/o registers already in use\n");
434 			goto cleanup0;
435 		}
436 	}
437 	rename_region(ports, cmos_rtc.rtc->class_dev.class_id);
438 
439 	spin_lock_irq(&rtc_lock);
440 
441 	/* force periodic irq to CMOS reset default of 1024Hz;
442 	 *
443 	 * REVISIT it's been reported that at least one x86_64 ALI mobo
444 	 * doesn't use 32KHz here ... for portability we might need to
445 	 * do something about other clock frequencies.
446 	 */
447 	CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
448 	cmos_rtc.rtc->irq_freq = 1024;
449 
450 	/* disable irqs.
451 	 *
452 	 * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
453 	 * allegedly some older rtcs need that to handle irqs properly
454 	 */
455 	rtc_control = CMOS_READ(RTC_CONTROL);
456 	rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE);
457 	CMOS_WRITE(rtc_control, RTC_CONTROL);
458 	CMOS_READ(RTC_INTR_FLAGS);
459 
460 	spin_unlock_irq(&rtc_lock);
461 
462 	/* FIXME teach the alarm code how to handle binary mode;
463 	 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
464 	 */
465 	if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY))) {
466 		dev_dbg(dev, "only 24-hr BCD mode supported\n");
467 		retval = -ENXIO;
468 		goto cleanup1;
469 	}
470 
471 	if (is_valid_irq(rtc_irq))
472 		retval = request_irq(rtc_irq, cmos_interrupt, IRQF_DISABLED,
473 				cmos_rtc.rtc->class_dev.class_id,
474 				&cmos_rtc.rtc->class_dev);
475 	if (retval < 0) {
476 		dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
477 		goto cleanup1;
478 	}
479 
480 	/* REVISIT optionally make 50 or 114 bytes NVRAM available,
481 	 * like rtc-ds1553, rtc-ds1742 ... this will often include
482 	 * registers for century, and day/month alarm.
483 	 */
484 
485 	pr_info("%s: alarms up to one %s%s\n",
486 			cmos_rtc.rtc->class_dev.class_id,
487 			is_valid_irq(rtc_irq)
488 				?  (cmos_rtc.mon_alrm
489 					? "year"
490 					: (cmos_rtc.day_alrm
491 						? "month" : "day"))
492 				: "no",
493 			cmos_rtc.century ? ", y3k" : ""
494 			);
495 
496 	return 0;
497 
498 cleanup1:
499 	rename_region(ports, NULL);
500 cleanup0:
501 	rtc_device_unregister(cmos_rtc.rtc);
502 	return retval;
503 }
504 
505 static void cmos_do_shutdown(void)
506 {
507 	unsigned char	rtc_control;
508 
509 	spin_lock_irq(&rtc_lock);
510 	rtc_control = CMOS_READ(RTC_CONTROL);
511 	rtc_control &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
512 	CMOS_WRITE(rtc_control, RTC_CONTROL);
513 	CMOS_READ(RTC_INTR_FLAGS);
514 	spin_unlock_irq(&rtc_lock);
515 }
516 
517 static void __exit cmos_do_remove(struct device *dev)
518 {
519 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
520 
521 	cmos_do_shutdown();
522 
523 	if (is_pnpacpi())
524 		release_resource(cmos->iomem);
525 	rename_region(cmos->iomem, NULL);
526 
527 	if (is_valid_irq(cmos->irq))
528 		free_irq(cmos->irq, &cmos_rtc.rtc->class_dev);
529 
530 	rtc_device_unregister(cmos_rtc.rtc);
531 
532 	cmos_rtc.dev = NULL;
533 	dev_set_drvdata(dev, NULL);
534 }
535 
536 #ifdef	CONFIG_PM
537 
538 static int cmos_suspend(struct device *dev, pm_message_t mesg)
539 {
540 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
541 	int		do_wake = device_may_wakeup(dev);
542 	unsigned char	tmp;
543 
544 	/* only the alarm might be a wakeup event source */
545 	spin_lock_irq(&rtc_lock);
546 	cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
547 	if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
548 		unsigned char	irqstat;
549 
550 		if (do_wake)
551 			tmp &= ~(RTC_PIE|RTC_UIE);
552 		else
553 			tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
554 		CMOS_WRITE(tmp, RTC_CONTROL);
555 		irqstat = CMOS_READ(RTC_INTR_FLAGS);
556 		irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF;
557 		if (is_intr(irqstat))
558 			rtc_update_irq(&cmos->rtc->class_dev, 1, irqstat);
559 	}
560 	spin_unlock_irq(&rtc_lock);
561 
562 	/* ACPI HOOK:  enable ACPI_EVENT_RTC when (tmp & RTC_AIE)
563 	 * ... it'd be best if we could do that under rtc_lock.
564 	 */
565 
566 	pr_debug("%s: suspend%s, ctrl %02x\n",
567 			cmos_rtc.rtc->class_dev.class_id,
568 			(tmp & RTC_AIE) ? ", alarm may wake" : "",
569 			tmp);
570 
571 	return 0;
572 }
573 
574 static int cmos_resume(struct device *dev)
575 {
576 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
577 	unsigned char	tmp = cmos->suspend_ctrl;
578 
579 	/* REVISIT:  a mechanism to resync the system clock (jiffies)
580 	 * on resume should be portable between platforms ...
581 	 */
582 
583 	/* re-enable any irqs previously active */
584 	if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
585 
586 		/* ACPI HOOK:  disable ACPI_EVENT_RTC when (tmp & RTC_AIE) */
587 
588 		spin_lock_irq(&rtc_lock);
589 		CMOS_WRITE(tmp, RTC_CONTROL);
590 		tmp = CMOS_READ(RTC_INTR_FLAGS);
591 		tmp &= (cmos->suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
592 		if (is_intr(tmp))
593 			rtc_update_irq(&cmos->rtc->class_dev, 1, tmp);
594 		spin_unlock_irq(&rtc_lock);
595 	}
596 
597 	pr_debug("%s: resume, ctrl %02x\n",
598 			cmos_rtc.rtc->class_dev.class_id,
599 			cmos->suspend_ctrl);
600 
601 
602 	return 0;
603 }
604 
605 #else
606 #define	cmos_suspend	NULL
607 #define	cmos_resume	NULL
608 #endif
609 
610 /*----------------------------------------------------------------*/
611 
612 /* The "CMOS" RTC normally lives on the platform_bus.  On ACPI systems,
613  * the device node will always be created as a PNPACPI device.
614  */
615 
616 #ifdef	CONFIG_PNPACPI
617 
618 #include <linux/pnp.h>
619 
620 static int __devinit
621 cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
622 {
623 	/* REVISIT paranoia argues for a shutdown notifier, since PNP
624 	 * drivers can't provide shutdown() methods to disable IRQs.
625 	 * Or better yet, fix PNP to allow those methods...
626 	 */
627 	return cmos_do_probe(&pnp->dev,
628 			&pnp->res.port_resource[0],
629 			pnp->res.irq_resource[0].start);
630 }
631 
632 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
633 {
634 	cmos_do_remove(&pnp->dev);
635 }
636 
637 #ifdef	CONFIG_PM
638 
639 static int cmos_pnp_suspend(struct pnp_dev *pnp, pm_message_t mesg)
640 {
641 	return cmos_suspend(&pnp->dev, mesg);
642 }
643 
644 static int cmos_pnp_resume(struct pnp_dev *pnp)
645 {
646 	return cmos_resume(&pnp->dev);
647 }
648 
649 #else
650 #define	cmos_pnp_suspend	NULL
651 #define	cmos_pnp_resume		NULL
652 #endif
653 
654 
655 static const struct pnp_device_id rtc_ids[] = {
656 	{ .id = "PNP0b00", },
657 	{ .id = "PNP0b01", },
658 	{ .id = "PNP0b02", },
659 	{ },
660 };
661 MODULE_DEVICE_TABLE(pnp, rtc_ids);
662 
663 static struct pnp_driver cmos_pnp_driver = {
664 	.name		= (char *) driver_name,
665 	.id_table	= rtc_ids,
666 	.probe		= cmos_pnp_probe,
667 	.remove		= __exit_p(cmos_pnp_remove),
668 
669 	/* flag ensures resume() gets called, and stops syslog spam */
670 	.flags		= PNP_DRIVER_RES_DO_NOT_CHANGE,
671 	.suspend	= cmos_pnp_suspend,
672 	.resume		= cmos_pnp_resume,
673 };
674 
675 static int __init cmos_init(void)
676 {
677 	return pnp_register_driver(&cmos_pnp_driver);
678 }
679 module_init(cmos_init);
680 
681 static void __exit cmos_exit(void)
682 {
683 	pnp_unregister_driver(&cmos_pnp_driver);
684 }
685 module_exit(cmos_exit);
686 
687 #else	/* no PNPACPI */
688 
689 /*----------------------------------------------------------------*/
690 
691 /* Platform setup should have set up an RTC device, when PNPACPI is
692  * unavailable ... this could happen even on (older) PCs.
693  */
694 
695 static int __init cmos_platform_probe(struct platform_device *pdev)
696 {
697 	return cmos_do_probe(&pdev->dev,
698 			platform_get_resource(pdev, IORESOURCE_IO, 0),
699 			platform_get_irq(pdev, 0));
700 }
701 
702 static int __exit cmos_platform_remove(struct platform_device *pdev)
703 {
704 	cmos_do_remove(&pdev->dev);
705 	return 0;
706 }
707 
708 static void cmos_platform_shutdown(struct platform_device *pdev)
709 {
710 	cmos_do_shutdown();
711 }
712 
713 static struct platform_driver cmos_platform_driver = {
714 	.remove		= __exit_p(cmos_platform_remove),
715 	.shutdown	= cmos_platform_shutdown,
716 	.driver = {
717 		.name		= (char *) driver_name,
718 		.suspend	= cmos_suspend,
719 		.resume		= cmos_resume,
720 	}
721 };
722 
723 static int __init cmos_init(void)
724 {
725 	return platform_driver_probe(&cmos_platform_driver,
726 			cmos_platform_probe);
727 }
728 module_init(cmos_init);
729 
730 static void __exit cmos_exit(void)
731 {
732 	platform_driver_unregister(&cmos_platform_driver);
733 }
734 module_exit(cmos_exit);
735 
736 
737 #endif	/* !PNPACPI */
738 
739 MODULE_AUTHOR("David Brownell");
740 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
741 MODULE_LICENSE("GPL");
742