xref: /linux/drivers/rtc/rtc-ds1685.c (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae)
1 /*
2  * An rtc driver for the Dallas/Maxim DS1685/DS1687 and related real-time
3  * chips.
4  *
5  * Copyright (C) 2011-2014 Joshua Kinard <kumba@gentoo.org>.
6  * Copyright (C) 2009 Matthias Fuchs <matthias.fuchs@esd-electronics.com>.
7  *
8  * References:
9  *    DS1685/DS1687 3V/5V Real-Time Clocks, 19-5215, Rev 4/10.
10  *    DS17x85/DS17x87 3V/5V Real-Time Clocks, 19-5222, Rev 4/10.
11  *    DS1689/DS1693 3V/5V Serialized Real-Time Clocks, Rev 112105.
12  *    Application Note 90, Using the Multiplex Bus RTC Extended Features.
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License version 2 as
16  * published by the Free Software Foundation.
17  */
18 
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 
21 #include <linux/bcd.h>
22 #include <linux/delay.h>
23 #include <linux/io.h>
24 #include <linux/module.h>
25 #include <linux/platform_device.h>
26 #include <linux/rtc.h>
27 #include <linux/workqueue.h>
28 
29 #include <linux/rtc/ds1685.h>
30 
31 #ifdef CONFIG_PROC_FS
32 #include <linux/proc_fs.h>
33 #endif
34 
35 
36 /* ----------------------------------------------------------------------- */
37 /* Standard read/write functions if platform does not provide overrides */
38 
39 /**
40  * ds1685_read - read a value from an rtc register.
41  * @rtc: pointer to the ds1685 rtc structure.
42  * @reg: the register address to read.
43  */
44 static u8
45 ds1685_read(struct ds1685_priv *rtc, int reg)
46 {
47 	return readb((u8 __iomem *)rtc->regs +
48 		     (reg * rtc->regstep));
49 }
50 
51 /**
52  * ds1685_write - write a value to an rtc register.
53  * @rtc: pointer to the ds1685 rtc structure.
54  * @reg: the register address to write.
55  * @value: value to write to the register.
56  */
57 static void
58 ds1685_write(struct ds1685_priv *rtc, int reg, u8 value)
59 {
60 	writeb(value, ((u8 __iomem *)rtc->regs +
61 		       (reg * rtc->regstep)));
62 }
63 /* ----------------------------------------------------------------------- */
64 
65 
66 /* ----------------------------------------------------------------------- */
67 /* Inlined functions */
68 
69 /**
70  * ds1685_rtc_bcd2bin - bcd2bin wrapper in case platform doesn't support BCD.
71  * @rtc: pointer to the ds1685 rtc structure.
72  * @val: u8 time value to consider converting.
73  * @bcd_mask: u8 mask value if BCD mode is used.
74  * @bin_mask: u8 mask value if BIN mode is used.
75  *
76  * Returns the value, converted to BIN if originally in BCD and bcd_mode TRUE.
77  */
78 static inline u8
79 ds1685_rtc_bcd2bin(struct ds1685_priv *rtc, u8 val, u8 bcd_mask, u8 bin_mask)
80 {
81 	if (rtc->bcd_mode)
82 		return (bcd2bin(val) & bcd_mask);
83 
84 	return (val & bin_mask);
85 }
86 
87 /**
88  * ds1685_rtc_bin2bcd - bin2bcd wrapper in case platform doesn't support BCD.
89  * @rtc: pointer to the ds1685 rtc structure.
90  * @val: u8 time value to consider converting.
91  * @bin_mask: u8 mask value if BIN mode is used.
92  * @bcd_mask: u8 mask value if BCD mode is used.
93  *
94  * Returns the value, converted to BCD if originally in BIN and bcd_mode TRUE.
95  */
96 static inline u8
97 ds1685_rtc_bin2bcd(struct ds1685_priv *rtc, u8 val, u8 bin_mask, u8 bcd_mask)
98 {
99 	if (rtc->bcd_mode)
100 		return (bin2bcd(val) & bcd_mask);
101 
102 	return (val & bin_mask);
103 }
104 
105 /**
106  * s1685_rtc_check_mday - check validity of the day of month.
107  * @rtc: pointer to the ds1685 rtc structure.
108  * @mday: day of month.
109  *
110  * Returns -EDOM if the day of month is not within 1..31 range.
111  */
112 static inline int
113 ds1685_rtc_check_mday(struct ds1685_priv *rtc, u8 mday)
114 {
115 	if (rtc->bcd_mode) {
116 		if (mday < 0x01 || mday > 0x31 || (mday & 0x0f) > 0x09)
117 			return -EDOM;
118 	} else {
119 		if (mday < 1 || mday > 31)
120 			return -EDOM;
121 	}
122 	return 0;
123 }
124 
125 /**
126  * ds1685_rtc_switch_to_bank0 - switch the rtc to bank 0.
127  * @rtc: pointer to the ds1685 rtc structure.
128  */
129 static inline void
130 ds1685_rtc_switch_to_bank0(struct ds1685_priv *rtc)
131 {
132 	rtc->write(rtc, RTC_CTRL_A,
133 		   (rtc->read(rtc, RTC_CTRL_A) & ~(RTC_CTRL_A_DV0)));
134 }
135 
136 /**
137  * ds1685_rtc_switch_to_bank1 - switch the rtc to bank 1.
138  * @rtc: pointer to the ds1685 rtc structure.
139  */
140 static inline void
141 ds1685_rtc_switch_to_bank1(struct ds1685_priv *rtc)
142 {
143 	rtc->write(rtc, RTC_CTRL_A,
144 		   (rtc->read(rtc, RTC_CTRL_A) | RTC_CTRL_A_DV0));
145 }
146 
147 /**
148  * ds1685_rtc_begin_data_access - prepare the rtc for data access.
149  * @rtc: pointer to the ds1685 rtc structure.
150  *
151  * This takes several steps to prepare the rtc for access to get/set time
152  * and alarm values from the rtc registers:
153  *  - Sets the SET bit in Control Register B.
154  *  - Reads Ext Control Register 4A and checks the INCR bit.
155  *  - If INCR is active, a short delay is added before Ext Control Register 4A
156  *    is read again in a loop until INCR is inactive.
157  *  - Switches the rtc to bank 1.  This allows access to all relevant
158  *    data for normal rtc operation, as bank 0 contains only the nvram.
159  */
160 static inline void
161 ds1685_rtc_begin_data_access(struct ds1685_priv *rtc)
162 {
163 	/* Set the SET bit in Ctrl B */
164 	rtc->write(rtc, RTC_CTRL_B,
165 		   (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
166 
167 	/* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
168 	while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
169 		cpu_relax();
170 
171 	/* Switch to Bank 1 */
172 	ds1685_rtc_switch_to_bank1(rtc);
173 }
174 
175 /**
176  * ds1685_rtc_end_data_access - end data access on the rtc.
177  * @rtc: pointer to the ds1685 rtc structure.
178  *
179  * This ends what was started by ds1685_rtc_begin_data_access:
180  *  - Switches the rtc back to bank 0.
181  *  - Clears the SET bit in Control Register B.
182  */
183 static inline void
184 ds1685_rtc_end_data_access(struct ds1685_priv *rtc)
185 {
186 	/* Switch back to Bank 0 */
187 	ds1685_rtc_switch_to_bank1(rtc);
188 
189 	/* Clear the SET bit in Ctrl B */
190 	rtc->write(rtc, RTC_CTRL_B,
191 		   (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
192 }
193 
194 /**
195  * ds1685_rtc_begin_ctrl_access - prepare the rtc for ctrl access.
196  * @rtc: pointer to the ds1685 rtc structure.
197  * @flags: irq flags variable for spin_lock_irqsave.
198  *
199  * This takes several steps to prepare the rtc for access to read just the
200  * control registers:
201  *  - Sets a spinlock on the rtc IRQ.
202  *  - Switches the rtc to bank 1.  This allows access to the two extended
203  *    control registers.
204  *
205  * Only use this where you are certain another lock will not be held.
206  */
207 static inline void
208 ds1685_rtc_begin_ctrl_access(struct ds1685_priv *rtc, unsigned long *flags)
209 {
210 	spin_lock_irqsave(&rtc->lock, *flags);
211 	ds1685_rtc_switch_to_bank1(rtc);
212 }
213 
214 /**
215  * ds1685_rtc_end_ctrl_access - end ctrl access on the rtc.
216  * @rtc: pointer to the ds1685 rtc structure.
217  * @flags: irq flags variable for spin_unlock_irqrestore.
218  *
219  * This ends what was started by ds1685_rtc_begin_ctrl_access:
220  *  - Switches the rtc back to bank 0.
221  *  - Unsets the spinlock on the rtc IRQ.
222  */
223 static inline void
224 ds1685_rtc_end_ctrl_access(struct ds1685_priv *rtc, unsigned long flags)
225 {
226 	ds1685_rtc_switch_to_bank0(rtc);
227 	spin_unlock_irqrestore(&rtc->lock, flags);
228 }
229 
230 /**
231  * ds1685_rtc_get_ssn - retrieve the silicon serial number.
232  * @rtc: pointer to the ds1685 rtc structure.
233  * @ssn: u8 array to hold the bits of the silicon serial number.
234  *
235  * This number starts at 0x40, and is 8-bytes long, ending at 0x47. The
236  * first byte is the model number, the next six bytes are the serial number
237  * digits, and the final byte is a CRC check byte.  Together, they form the
238  * silicon serial number.
239  *
240  * These values are stored in bank1, so ds1685_rtc_switch_to_bank1 must be
241  * called first before calling this function, else data will be read out of
242  * the bank0 NVRAM.  Be sure to call ds1685_rtc_switch_to_bank0 when done.
243  */
244 static inline void
245 ds1685_rtc_get_ssn(struct ds1685_priv *rtc, u8 *ssn)
246 {
247 	ssn[0] = rtc->read(rtc, RTC_BANK1_SSN_MODEL);
248 	ssn[1] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_1);
249 	ssn[2] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_2);
250 	ssn[3] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_3);
251 	ssn[4] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_4);
252 	ssn[5] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_5);
253 	ssn[6] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_6);
254 	ssn[7] = rtc->read(rtc, RTC_BANK1_SSN_CRC);
255 }
256 /* ----------------------------------------------------------------------- */
257 
258 
259 /* ----------------------------------------------------------------------- */
260 /* Read/Set Time & Alarm functions */
261 
262 /**
263  * ds1685_rtc_read_time - reads the time registers.
264  * @dev: pointer to device structure.
265  * @tm: pointer to rtc_time structure.
266  */
267 static int
268 ds1685_rtc_read_time(struct device *dev, struct rtc_time *tm)
269 {
270 	struct platform_device *pdev = to_platform_device(dev);
271 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
272 	u8 ctrlb, century;
273 	u8 seconds, minutes, hours, wday, mday, month, years;
274 
275 	/* Fetch the time info from the RTC registers. */
276 	ds1685_rtc_begin_data_access(rtc);
277 	seconds = rtc->read(rtc, RTC_SECS);
278 	minutes = rtc->read(rtc, RTC_MINS);
279 	hours   = rtc->read(rtc, RTC_HRS);
280 	wday    = rtc->read(rtc, RTC_WDAY);
281 	mday    = rtc->read(rtc, RTC_MDAY);
282 	month   = rtc->read(rtc, RTC_MONTH);
283 	years   = rtc->read(rtc, RTC_YEAR);
284 	century = rtc->read(rtc, RTC_CENTURY);
285 	ctrlb   = rtc->read(rtc, RTC_CTRL_B);
286 	ds1685_rtc_end_data_access(rtc);
287 
288 	/* bcd2bin if needed, perform fixups, and store to rtc_time. */
289 	years        = ds1685_rtc_bcd2bin(rtc, years, RTC_YEAR_BCD_MASK,
290 					  RTC_YEAR_BIN_MASK);
291 	century      = ds1685_rtc_bcd2bin(rtc, century, RTC_CENTURY_MASK,
292 					  RTC_CENTURY_MASK);
293 	tm->tm_sec   = ds1685_rtc_bcd2bin(rtc, seconds, RTC_SECS_BCD_MASK,
294 					  RTC_SECS_BIN_MASK);
295 	tm->tm_min   = ds1685_rtc_bcd2bin(rtc, minutes, RTC_MINS_BCD_MASK,
296 					  RTC_MINS_BIN_MASK);
297 	tm->tm_hour  = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_24_BCD_MASK,
298 					  RTC_HRS_24_BIN_MASK);
299 	tm->tm_wday  = (ds1685_rtc_bcd2bin(rtc, wday, RTC_WDAY_MASK,
300 					   RTC_WDAY_MASK) - 1);
301 	tm->tm_mday  = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
302 					  RTC_MDAY_BIN_MASK);
303 	tm->tm_mon   = (ds1685_rtc_bcd2bin(rtc, month, RTC_MONTH_BCD_MASK,
304 					   RTC_MONTH_BIN_MASK) - 1);
305 	tm->tm_year  = ((years + (century * 100)) - 1900);
306 	tm->tm_yday  = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
307 	tm->tm_isdst = 0; /* RTC has hardcoded timezone, so don't use. */
308 
309 	return rtc_valid_tm(tm);
310 }
311 
312 /**
313  * ds1685_rtc_set_time - sets the time registers.
314  * @dev: pointer to device structure.
315  * @tm: pointer to rtc_time structure.
316  */
317 static int
318 ds1685_rtc_set_time(struct device *dev, struct rtc_time *tm)
319 {
320 	struct platform_device *pdev = to_platform_device(dev);
321 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
322 	u8 ctrlb, seconds, minutes, hours, wday, mday, month, years, century;
323 
324 	/* Fetch the time info from rtc_time. */
325 	seconds = ds1685_rtc_bin2bcd(rtc, tm->tm_sec, RTC_SECS_BIN_MASK,
326 				     RTC_SECS_BCD_MASK);
327 	minutes = ds1685_rtc_bin2bcd(rtc, tm->tm_min, RTC_MINS_BIN_MASK,
328 				     RTC_MINS_BCD_MASK);
329 	hours   = ds1685_rtc_bin2bcd(rtc, tm->tm_hour, RTC_HRS_24_BIN_MASK,
330 				     RTC_HRS_24_BCD_MASK);
331 	wday    = ds1685_rtc_bin2bcd(rtc, (tm->tm_wday + 1), RTC_WDAY_MASK,
332 				     RTC_WDAY_MASK);
333 	mday    = ds1685_rtc_bin2bcd(rtc, tm->tm_mday, RTC_MDAY_BIN_MASK,
334 				     RTC_MDAY_BCD_MASK);
335 	month   = ds1685_rtc_bin2bcd(rtc, (tm->tm_mon + 1), RTC_MONTH_BIN_MASK,
336 				     RTC_MONTH_BCD_MASK);
337 	years   = ds1685_rtc_bin2bcd(rtc, (tm->tm_year % 100),
338 				     RTC_YEAR_BIN_MASK, RTC_YEAR_BCD_MASK);
339 	century = ds1685_rtc_bin2bcd(rtc, ((tm->tm_year + 1900) / 100),
340 				     RTC_CENTURY_MASK, RTC_CENTURY_MASK);
341 
342 	/*
343 	 * Perform Sanity Checks:
344 	 *   - Months: !> 12, Month Day != 0.
345 	 *   - Month Day !> Max days in current month.
346 	 *   - Hours !>= 24, Mins !>= 60, Secs !>= 60, & Weekday !> 7.
347 	 */
348 	if ((tm->tm_mon > 11) || (mday == 0))
349 		return -EDOM;
350 
351 	if (tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year))
352 		return -EDOM;
353 
354 	if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) ||
355 	    (tm->tm_sec >= 60)  || (wday > 7))
356 		return -EDOM;
357 
358 	/*
359 	 * Set the data mode to use and store the time values in the
360 	 * RTC registers.
361 	 */
362 	ds1685_rtc_begin_data_access(rtc);
363 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
364 	if (rtc->bcd_mode)
365 		ctrlb &= ~(RTC_CTRL_B_DM);
366 	else
367 		ctrlb |= RTC_CTRL_B_DM;
368 	rtc->write(rtc, RTC_CTRL_B, ctrlb);
369 	rtc->write(rtc, RTC_SECS, seconds);
370 	rtc->write(rtc, RTC_MINS, minutes);
371 	rtc->write(rtc, RTC_HRS, hours);
372 	rtc->write(rtc, RTC_WDAY, wday);
373 	rtc->write(rtc, RTC_MDAY, mday);
374 	rtc->write(rtc, RTC_MONTH, month);
375 	rtc->write(rtc, RTC_YEAR, years);
376 	rtc->write(rtc, RTC_CENTURY, century);
377 	ds1685_rtc_end_data_access(rtc);
378 
379 	return 0;
380 }
381 
382 /**
383  * ds1685_rtc_read_alarm - reads the alarm registers.
384  * @dev: pointer to device structure.
385  * @alrm: pointer to rtc_wkalrm structure.
386  *
387  * There are three primary alarm registers: seconds, minutes, and hours.
388  * A fourth alarm register for the month date is also available in bank1 for
389  * kickstart/wakeup features.  The DS1685/DS1687 manual states that a
390  * "don't care" value ranging from 0xc0 to 0xff may be written into one or
391  * more of the three alarm bytes to act as a wildcard value.  The fourth
392  * byte doesn't support a "don't care" value.
393  */
394 static int
395 ds1685_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
396 {
397 	struct platform_device *pdev = to_platform_device(dev);
398 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
399 	u8 seconds, minutes, hours, mday, ctrlb, ctrlc;
400 	int ret;
401 
402 	/* Fetch the alarm info from the RTC alarm registers. */
403 	ds1685_rtc_begin_data_access(rtc);
404 	seconds	= rtc->read(rtc, RTC_SECS_ALARM);
405 	minutes	= rtc->read(rtc, RTC_MINS_ALARM);
406 	hours	= rtc->read(rtc, RTC_HRS_ALARM);
407 	mday	= rtc->read(rtc, RTC_MDAY_ALARM);
408 	ctrlb	= rtc->read(rtc, RTC_CTRL_B);
409 	ctrlc	= rtc->read(rtc, RTC_CTRL_C);
410 	ds1685_rtc_end_data_access(rtc);
411 
412 	/* Check the month date for validity. */
413 	ret = ds1685_rtc_check_mday(rtc, mday);
414 	if (ret)
415 		return ret;
416 
417 	/*
418 	 * Check the three alarm bytes.
419 	 *
420 	 * The Linux RTC system doesn't support the "don't care" capability
421 	 * of this RTC chip.  We check for it anyways in case support is
422 	 * added in the future and only assign when we care.
423 	 */
424 	if (likely(seconds < 0xc0))
425 		alrm->time.tm_sec = ds1685_rtc_bcd2bin(rtc, seconds,
426 						       RTC_SECS_BCD_MASK,
427 						       RTC_SECS_BIN_MASK);
428 
429 	if (likely(minutes < 0xc0))
430 		alrm->time.tm_min = ds1685_rtc_bcd2bin(rtc, minutes,
431 						       RTC_MINS_BCD_MASK,
432 						       RTC_MINS_BIN_MASK);
433 
434 	if (likely(hours < 0xc0))
435 		alrm->time.tm_hour = ds1685_rtc_bcd2bin(rtc, hours,
436 							RTC_HRS_24_BCD_MASK,
437 							RTC_HRS_24_BIN_MASK);
438 
439 	/* Write the data to rtc_wkalrm. */
440 	alrm->time.tm_mday = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
441 						RTC_MDAY_BIN_MASK);
442 	alrm->enabled = !!(ctrlb & RTC_CTRL_B_AIE);
443 	alrm->pending = !!(ctrlc & RTC_CTRL_C_AF);
444 
445 	return 0;
446 }
447 
448 /**
449  * ds1685_rtc_set_alarm - sets the alarm in registers.
450  * @dev: pointer to device structure.
451  * @alrm: pointer to rtc_wkalrm structure.
452  */
453 static int
454 ds1685_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
455 {
456 	struct platform_device *pdev = to_platform_device(dev);
457 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
458 	u8 ctrlb, seconds, minutes, hours, mday;
459 	int ret;
460 
461 	/* Fetch the alarm info and convert to BCD. */
462 	seconds	= ds1685_rtc_bin2bcd(rtc, alrm->time.tm_sec,
463 				     RTC_SECS_BIN_MASK,
464 				     RTC_SECS_BCD_MASK);
465 	minutes	= ds1685_rtc_bin2bcd(rtc, alrm->time.tm_min,
466 				     RTC_MINS_BIN_MASK,
467 				     RTC_MINS_BCD_MASK);
468 	hours	= ds1685_rtc_bin2bcd(rtc, alrm->time.tm_hour,
469 				     RTC_HRS_24_BIN_MASK,
470 				     RTC_HRS_24_BCD_MASK);
471 	mday	= ds1685_rtc_bin2bcd(rtc, alrm->time.tm_mday,
472 				     RTC_MDAY_BIN_MASK,
473 				     RTC_MDAY_BCD_MASK);
474 
475 	/* Check the month date for validity. */
476 	ret = ds1685_rtc_check_mday(rtc, mday);
477 	if (ret)
478 		return ret;
479 
480 	/*
481 	 * Check the three alarm bytes.
482 	 *
483 	 * The Linux RTC system doesn't support the "don't care" capability
484 	 * of this RTC chip because rtc_valid_tm tries to validate every
485 	 * field, and we only support four fields.  We put the support
486 	 * here anyways for the future.
487 	 */
488 	if (unlikely(seconds >= 0xc0))
489 		seconds = 0xff;
490 
491 	if (unlikely(minutes >= 0xc0))
492 		minutes = 0xff;
493 
494 	if (unlikely(hours >= 0xc0))
495 		hours = 0xff;
496 
497 	alrm->time.tm_mon	= -1;
498 	alrm->time.tm_year	= -1;
499 	alrm->time.tm_wday	= -1;
500 	alrm->time.tm_yday	= -1;
501 	alrm->time.tm_isdst	= -1;
502 
503 	/* Disable the alarm interrupt first. */
504 	ds1685_rtc_begin_data_access(rtc);
505 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
506 	rtc->write(rtc, RTC_CTRL_B, (ctrlb & ~(RTC_CTRL_B_AIE)));
507 
508 	/* Read ctrlc to clear RTC_CTRL_C_AF. */
509 	rtc->read(rtc, RTC_CTRL_C);
510 
511 	/*
512 	 * Set the data mode to use and store the time values in the
513 	 * RTC registers.
514 	 */
515 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
516 	if (rtc->bcd_mode)
517 		ctrlb &= ~(RTC_CTRL_B_DM);
518 	else
519 		ctrlb |= RTC_CTRL_B_DM;
520 	rtc->write(rtc, RTC_CTRL_B, ctrlb);
521 	rtc->write(rtc, RTC_SECS_ALARM, seconds);
522 	rtc->write(rtc, RTC_MINS_ALARM, minutes);
523 	rtc->write(rtc, RTC_HRS_ALARM, hours);
524 	rtc->write(rtc, RTC_MDAY_ALARM, mday);
525 
526 	/* Re-enable the alarm if needed. */
527 	if (alrm->enabled) {
528 		ctrlb = rtc->read(rtc, RTC_CTRL_B);
529 		ctrlb |= RTC_CTRL_B_AIE;
530 		rtc->write(rtc, RTC_CTRL_B, ctrlb);
531 	}
532 
533 	/* Done! */
534 	ds1685_rtc_end_data_access(rtc);
535 
536 	return 0;
537 }
538 /* ----------------------------------------------------------------------- */
539 
540 
541 /* ----------------------------------------------------------------------- */
542 /* /dev/rtcX Interface functions */
543 
544 /**
545  * ds1685_rtc_alarm_irq_enable - replaces ioctl() RTC_AIE on/off.
546  * @dev: pointer to device structure.
547  * @enabled: flag indicating whether to enable or disable.
548  */
549 static int
550 ds1685_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
551 {
552 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
553 	unsigned long flags = 0;
554 
555 	/* Enable/disable the Alarm IRQ-Enable flag. */
556 	spin_lock_irqsave(&rtc->lock, flags);
557 
558 	/* Flip the requisite interrupt-enable bit. */
559 	if (enabled)
560 		rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) |
561 					     RTC_CTRL_B_AIE));
562 	else
563 		rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) &
564 					     ~(RTC_CTRL_B_AIE)));
565 
566 	/* Read Control C to clear all the flag bits. */
567 	rtc->read(rtc, RTC_CTRL_C);
568 	spin_unlock_irqrestore(&rtc->lock, flags);
569 
570 	return 0;
571 }
572 /* ----------------------------------------------------------------------- */
573 
574 
575 /* ----------------------------------------------------------------------- */
576 /* IRQ handler & workqueue. */
577 
578 /**
579  * ds1685_rtc_irq_handler - IRQ handler.
580  * @irq: IRQ number.
581  * @dev_id: platform device pointer.
582  */
583 static irqreturn_t
584 ds1685_rtc_irq_handler(int irq, void *dev_id)
585 {
586 	struct platform_device *pdev = dev_id;
587 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
588 	u8 ctrlb, ctrlc;
589 	unsigned long events = 0;
590 	u8 num_irqs = 0;
591 
592 	/* Abort early if the device isn't ready yet (i.e., DEBUG_SHIRQ). */
593 	if (unlikely(!rtc))
594 		return IRQ_HANDLED;
595 
596 	/* Ctrlb holds the interrupt-enable bits and ctrlc the flag bits. */
597 	spin_lock(&rtc->lock);
598 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
599 	ctrlc = rtc->read(rtc, RTC_CTRL_C);
600 
601 	/* Is the IRQF bit set? */
602 	if (likely(ctrlc & RTC_CTRL_C_IRQF)) {
603 		/*
604 		 * We need to determine if it was one of the standard
605 		 * events: PF, AF, or UF.  If so, we handle them and
606 		 * update the RTC core.
607 		 */
608 		if (likely(ctrlc & RTC_CTRL_B_PAU_MASK)) {
609 			events = RTC_IRQF;
610 
611 			/* Check for a periodic interrupt. */
612 			if ((ctrlb & RTC_CTRL_B_PIE) &&
613 			    (ctrlc & RTC_CTRL_C_PF)) {
614 				events |= RTC_PF;
615 				num_irqs++;
616 			}
617 
618 			/* Check for an alarm interrupt. */
619 			if ((ctrlb & RTC_CTRL_B_AIE) &&
620 			    (ctrlc & RTC_CTRL_C_AF)) {
621 				events |= RTC_AF;
622 				num_irqs++;
623 			}
624 
625 			/* Check for an update interrupt. */
626 			if ((ctrlb & RTC_CTRL_B_UIE) &&
627 			    (ctrlc & RTC_CTRL_C_UF)) {
628 				events |= RTC_UF;
629 				num_irqs++;
630 			}
631 
632 			rtc_update_irq(rtc->dev, num_irqs, events);
633 		} else {
634 			/*
635 			 * One of the "extended" interrupts was received that
636 			 * is not recognized by the RTC core.  These need to
637 			 * be handled in task context as they can call other
638 			 * functions and the time spent in irq context needs
639 			 * to be minimized.  Schedule them into a workqueue
640 			 * and inform the RTC core that the IRQs were handled.
641 			 */
642 			spin_unlock(&rtc->lock);
643 			schedule_work(&rtc->work);
644 			rtc_update_irq(rtc->dev, 0, 0);
645 			return IRQ_HANDLED;
646 		}
647 	}
648 	spin_unlock(&rtc->lock);
649 
650 	return events ? IRQ_HANDLED : IRQ_NONE;
651 }
652 
653 /**
654  * ds1685_rtc_work_queue - work queue handler.
655  * @work: work_struct containing data to work on in task context.
656  */
657 static void
658 ds1685_rtc_work_queue(struct work_struct *work)
659 {
660 	struct ds1685_priv *rtc = container_of(work,
661 					       struct ds1685_priv, work);
662 	struct platform_device *pdev = to_platform_device(&rtc->dev->dev);
663 	struct mutex *rtc_mutex = &rtc->dev->ops_lock;
664 	u8 ctrl4a, ctrl4b;
665 
666 	mutex_lock(rtc_mutex);
667 
668 	ds1685_rtc_switch_to_bank1(rtc);
669 	ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
670 	ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
671 
672 	/*
673 	 * Check for a kickstart interrupt. With Vcc applied, this
674 	 * typically means that the power button was pressed, so we
675 	 * begin the shutdown sequence.
676 	 */
677 	if ((ctrl4b & RTC_CTRL_4B_KSE) && (ctrl4a & RTC_CTRL_4A_KF)) {
678 		/* Briefly disable kickstarts to debounce button presses. */
679 		rtc->write(rtc, RTC_EXT_CTRL_4B,
680 			   (rtc->read(rtc, RTC_EXT_CTRL_4B) &
681 			    ~(RTC_CTRL_4B_KSE)));
682 
683 		/* Clear the kickstart flag. */
684 		rtc->write(rtc, RTC_EXT_CTRL_4A,
685 			   (ctrl4a & ~(RTC_CTRL_4A_KF)));
686 
687 
688 		/*
689 		 * Sleep 500ms before re-enabling kickstarts.  This allows
690 		 * adequate time to avoid reading signal jitter as additional
691 		 * button presses.
692 		 */
693 		msleep(500);
694 		rtc->write(rtc, RTC_EXT_CTRL_4B,
695 			   (rtc->read(rtc, RTC_EXT_CTRL_4B) |
696 			    RTC_CTRL_4B_KSE));
697 
698 		/* Call the platform pre-poweroff function. Else, shutdown. */
699 		if (rtc->prepare_poweroff != NULL)
700 			rtc->prepare_poweroff();
701 		else
702 			ds1685_rtc_poweroff(pdev);
703 	}
704 
705 	/*
706 	 * Check for a wake-up interrupt.  With Vcc applied, this is
707 	 * essentially a second alarm interrupt, except it takes into
708 	 * account the 'date' register in bank1 in addition to the
709 	 * standard three alarm registers.
710 	 */
711 	if ((ctrl4b & RTC_CTRL_4B_WIE) && (ctrl4a & RTC_CTRL_4A_WF)) {
712 		rtc->write(rtc, RTC_EXT_CTRL_4A,
713 			   (ctrl4a & ~(RTC_CTRL_4A_WF)));
714 
715 		/* Call the platform wake_alarm function if defined. */
716 		if (rtc->wake_alarm != NULL)
717 			rtc->wake_alarm();
718 		else
719 			dev_warn(&pdev->dev,
720 				 "Wake Alarm IRQ just occurred!\n");
721 	}
722 
723 	/*
724 	 * Check for a ram-clear interrupt.  This happens if RIE=1 and RF=0
725 	 * when RCE=1 in 4B.  This clears all NVRAM bytes in bank0 by setting
726 	 * each byte to a logic 1.  This has no effect on any extended
727 	 * NV-SRAM that might be present, nor on the time/calendar/alarm
728 	 * registers.  After a ram-clear is completed, there is a minimum
729 	 * recovery time of ~150ms in which all reads/writes are locked out.
730 	 * NOTE: A ram-clear can still occur if RCE=1 and RIE=0.  We cannot
731 	 * catch this scenario.
732 	 */
733 	if ((ctrl4b & RTC_CTRL_4B_RIE) && (ctrl4a & RTC_CTRL_4A_RF)) {
734 		rtc->write(rtc, RTC_EXT_CTRL_4A,
735 			   (ctrl4a & ~(RTC_CTRL_4A_RF)));
736 		msleep(150);
737 
738 		/* Call the platform post_ram_clear function if defined. */
739 		if (rtc->post_ram_clear != NULL)
740 			rtc->post_ram_clear();
741 		else
742 			dev_warn(&pdev->dev,
743 				 "RAM-Clear IRQ just occurred!\n");
744 	}
745 	ds1685_rtc_switch_to_bank0(rtc);
746 
747 	mutex_unlock(rtc_mutex);
748 }
749 /* ----------------------------------------------------------------------- */
750 
751 
752 /* ----------------------------------------------------------------------- */
753 /* ProcFS interface */
754 
755 #ifdef CONFIG_PROC_FS
756 #define NUM_REGS	6	/* Num of control registers. */
757 #define NUM_BITS	8	/* Num bits per register. */
758 #define NUM_SPACES	4	/* Num spaces between each bit. */
759 
760 /*
761  * Periodic Interrupt Rates.
762  */
763 static const char *ds1685_rtc_pirq_rate[16] = {
764 	"none", "3.90625ms", "7.8125ms", "0.122070ms", "0.244141ms",
765 	"0.488281ms", "0.9765625ms", "1.953125ms", "3.90625ms", "7.8125ms",
766 	"15.625ms", "31.25ms", "62.5ms", "125ms", "250ms", "500ms"
767 };
768 
769 /*
770  * Square-Wave Output Frequencies.
771  */
772 static const char *ds1685_rtc_sqw_freq[16] = {
773 	"none", "256Hz", "128Hz", "8192Hz", "4096Hz", "2048Hz", "1024Hz",
774 	"512Hz", "256Hz", "128Hz", "64Hz", "32Hz", "16Hz", "8Hz", "4Hz", "2Hz"
775 };
776 
777 #ifdef CONFIG_RTC_DS1685_PROC_REGS
778 /**
779  * ds1685_rtc_print_regs - helper function to print register values.
780  * @hex: hex byte to convert into binary bits.
781  * @dest: destination char array.
782  *
783  * This is basically a hex->binary function, just with extra spacing between
784  * the digits.  It only works on 1-byte values (8 bits).
785  */
786 static char*
787 ds1685_rtc_print_regs(u8 hex, char *dest)
788 {
789 	u32 i, j;
790 	char *tmp = dest;
791 
792 	for (i = 0; i < NUM_BITS; i++) {
793 		*tmp++ = ((hex & 0x80) != 0 ? '1' : '0');
794 		for (j = 0; j < NUM_SPACES; j++)
795 			*tmp++ = ' ';
796 		hex <<= 1;
797 	}
798 	*tmp++ = '\0';
799 
800 	return dest;
801 }
802 #endif
803 
804 /**
805  * ds1685_rtc_proc - procfs access function.
806  * @dev: pointer to device structure.
807  * @seq: pointer to seq_file structure.
808  */
809 static int
810 ds1685_rtc_proc(struct device *dev, struct seq_file *seq)
811 {
812 	struct platform_device *pdev = to_platform_device(dev);
813 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
814 	u8 ctrla, ctrlb, ctrlc, ctrld, ctrl4a, ctrl4b, ssn[8];
815 	char *model;
816 #ifdef CONFIG_RTC_DS1685_PROC_REGS
817 	char bits[NUM_REGS][(NUM_BITS * NUM_SPACES) + NUM_BITS + 1];
818 #endif
819 
820 	/* Read all the relevant data from the control registers. */
821 	ds1685_rtc_switch_to_bank1(rtc);
822 	ds1685_rtc_get_ssn(rtc, ssn);
823 	ctrla = rtc->read(rtc, RTC_CTRL_A);
824 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
825 	ctrlc = rtc->read(rtc, RTC_CTRL_C);
826 	ctrld = rtc->read(rtc, RTC_CTRL_D);
827 	ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
828 	ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
829 	ds1685_rtc_switch_to_bank0(rtc);
830 
831 	/* Determine the RTC model. */
832 	switch (ssn[0]) {
833 	case RTC_MODEL_DS1685:
834 		model = "DS1685/DS1687\0";
835 		break;
836 	case RTC_MODEL_DS1689:
837 		model = "DS1689/DS1693\0";
838 		break;
839 	case RTC_MODEL_DS17285:
840 		model = "DS17285/DS17287\0";
841 		break;
842 	case RTC_MODEL_DS17485:
843 		model = "DS17485/DS17487\0";
844 		break;
845 	case RTC_MODEL_DS17885:
846 		model = "DS17885/DS17887\0";
847 		break;
848 	default:
849 		model = "Unknown\0";
850 		break;
851 	}
852 
853 	/* Print out the information. */
854 	seq_printf(seq,
855 	   "Model\t\t: %s\n"
856 	   "Oscillator\t: %s\n"
857 	   "12/24hr\t\t: %s\n"
858 	   "DST\t\t: %s\n"
859 	   "Data mode\t: %s\n"
860 	   "Battery\t\t: %s\n"
861 	   "Aux batt\t: %s\n"
862 	   "Update IRQ\t: %s\n"
863 	   "Periodic IRQ\t: %s\n"
864 	   "Periodic Rate\t: %s\n"
865 	   "SQW Freq\t: %s\n"
866 #ifdef CONFIG_RTC_DS1685_PROC_REGS
867 	   "Serial #\t: %8phC\n"
868 	   "Register Status\t:\n"
869 	   "   Ctrl A\t: UIP  DV2  DV1  DV0  RS3  RS2  RS1  RS0\n"
870 	   "\t\t:  %s\n"
871 	   "   Ctrl B\t: SET  PIE  AIE  UIE  SQWE  DM  2412 DSE\n"
872 	   "\t\t:  %s\n"
873 	   "   Ctrl C\t: IRQF  PF   AF   UF  ---  ---  ---  ---\n"
874 	   "\t\t:  %s\n"
875 	   "   Ctrl D\t: VRT  ---  ---  ---  ---  ---  ---  ---\n"
876 	   "\t\t:  %s\n"
877 #if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
878 	   "   Ctrl 4A\t: VRT2 INCR BME  ---  PAB   RF   WF   KF\n"
879 #else
880 	   "   Ctrl 4A\t: VRT2 INCR ---  ---  PAB   RF   WF   KF\n"
881 #endif
882 	   "\t\t:  %s\n"
883 	   "   Ctrl 4B\t: ABE  E32k  CS  RCE  PRS  RIE  WIE  KSE\n"
884 	   "\t\t:  %s\n",
885 #else
886 	   "Serial #\t: %8phC\n",
887 #endif
888 	   model,
889 	   ((ctrla & RTC_CTRL_A_DV1) ? "enabled" : "disabled"),
890 	   ((ctrlb & RTC_CTRL_B_2412) ? "24-hour" : "12-hour"),
891 	   ((ctrlb & RTC_CTRL_B_DSE) ? "enabled" : "disabled"),
892 	   ((ctrlb & RTC_CTRL_B_DM) ? "binary" : "BCD"),
893 	   ((ctrld & RTC_CTRL_D_VRT) ? "ok" : "exhausted or n/a"),
894 	   ((ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "exhausted or n/a"),
895 	   ((ctrlb & RTC_CTRL_B_UIE) ? "yes" : "no"),
896 	   ((ctrlb & RTC_CTRL_B_PIE) ? "yes" : "no"),
897 	   (!(ctrl4b & RTC_CTRL_4B_E32K) ?
898 	    ds1685_rtc_pirq_rate[(ctrla & RTC_CTRL_A_RS_MASK)] : "none"),
899 	   (!((ctrl4b & RTC_CTRL_4B_E32K)) ?
900 	    ds1685_rtc_sqw_freq[(ctrla & RTC_CTRL_A_RS_MASK)] : "32768Hz"),
901 #ifdef CONFIG_RTC_DS1685_PROC_REGS
902 	   ssn,
903 	   ds1685_rtc_print_regs(ctrla, bits[0]),
904 	   ds1685_rtc_print_regs(ctrlb, bits[1]),
905 	   ds1685_rtc_print_regs(ctrlc, bits[2]),
906 	   ds1685_rtc_print_regs(ctrld, bits[3]),
907 	   ds1685_rtc_print_regs(ctrl4a, bits[4]),
908 	   ds1685_rtc_print_regs(ctrl4b, bits[5]));
909 #else
910 	   ssn);
911 #endif
912 	return 0;
913 }
914 #else
915 #define ds1685_rtc_proc NULL
916 #endif /* CONFIG_PROC_FS */
917 /* ----------------------------------------------------------------------- */
918 
919 
920 /* ----------------------------------------------------------------------- */
921 /* RTC Class operations */
922 
923 static const struct rtc_class_ops
924 ds1685_rtc_ops = {
925 	.proc = ds1685_rtc_proc,
926 	.read_time = ds1685_rtc_read_time,
927 	.set_time = ds1685_rtc_set_time,
928 	.read_alarm = ds1685_rtc_read_alarm,
929 	.set_alarm = ds1685_rtc_set_alarm,
930 	.alarm_irq_enable = ds1685_rtc_alarm_irq_enable,
931 };
932 /* ----------------------------------------------------------------------- */
933 
934 
935 /* ----------------------------------------------------------------------- */
936 /* SysFS interface */
937 
938 #ifdef CONFIG_SYSFS
939 /**
940  * ds1685_rtc_sysfs_nvram_read - reads rtc nvram via sysfs.
941  * @file: pointer to file structure.
942  * @kobj: pointer to kobject structure.
943  * @bin_attr: pointer to bin_attribute structure.
944  * @buf: pointer to char array to hold the output.
945  * @pos: current file position pointer.
946  * @size: size of the data to read.
947  */
948 static ssize_t
949 ds1685_rtc_sysfs_nvram_read(struct file *filp, struct kobject *kobj,
950 			    struct bin_attribute *bin_attr, char *buf,
951 			    loff_t pos, size_t size)
952 {
953 	struct platform_device *pdev =
954 		to_platform_device(container_of(kobj, struct device, kobj));
955 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
956 	ssize_t count;
957 	unsigned long flags = 0;
958 
959 	spin_lock_irqsave(&rtc->lock, flags);
960 	ds1685_rtc_switch_to_bank0(rtc);
961 
962 	/* Read NVRAM in time and bank0 registers. */
963 	for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
964 	     count++, size--) {
965 		if (count < NVRAM_SZ_TIME)
966 			*buf++ = rtc->read(rtc, (NVRAM_TIME_BASE + pos++));
967 		else
968 			*buf++ = rtc->read(rtc, (NVRAM_BANK0_BASE + pos++));
969 	}
970 
971 #ifndef CONFIG_RTC_DRV_DS1689
972 	if (size > 0) {
973 		ds1685_rtc_switch_to_bank1(rtc);
974 
975 #ifndef CONFIG_RTC_DRV_DS1685
976 		/* Enable burst-mode on DS17x85/DS17x87 */
977 		rtc->write(rtc, RTC_EXT_CTRL_4A,
978 			   (rtc->read(rtc, RTC_EXT_CTRL_4A) |
979 			    RTC_CTRL_4A_BME));
980 
981 		/* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
982 		 * reading with burst-mode */
983 		rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
984 			   (pos - NVRAM_TOTAL_SZ_BANK0));
985 #endif
986 
987 		/* Read NVRAM in bank1 registers. */
988 		for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
989 		     count++, size--) {
990 #ifdef CONFIG_RTC_DRV_DS1685
991 			/* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
992 			 * before each read. */
993 			rtc->write(rtc, RTC_BANK1_RAM_ADDR,
994 				   (pos - NVRAM_TOTAL_SZ_BANK0));
995 #endif
996 			*buf++ = rtc->read(rtc, RTC_BANK1_RAM_DATA_PORT);
997 			pos++;
998 		}
999 
1000 #ifndef CONFIG_RTC_DRV_DS1685
1001 		/* Disable burst-mode on DS17x85/DS17x87 */
1002 		rtc->write(rtc, RTC_EXT_CTRL_4A,
1003 			   (rtc->read(rtc, RTC_EXT_CTRL_4A) &
1004 			    ~(RTC_CTRL_4A_BME)));
1005 #endif
1006 		ds1685_rtc_switch_to_bank0(rtc);
1007 	}
1008 #endif /* !CONFIG_RTC_DRV_DS1689 */
1009 	spin_unlock_irqrestore(&rtc->lock, flags);
1010 
1011 	/*
1012 	 * XXX: Bug? this appears to cause the function to get executed
1013 	 * several times in succession.  But it's the only way to actually get
1014 	 * data written out to a file.
1015 	 */
1016 	return count;
1017 }
1018 
1019 /**
1020  * ds1685_rtc_sysfs_nvram_write - writes rtc nvram via sysfs.
1021  * @file: pointer to file structure.
1022  * @kobj: pointer to kobject structure.
1023  * @bin_attr: pointer to bin_attribute structure.
1024  * @buf: pointer to char array to hold the input.
1025  * @pos: current file position pointer.
1026  * @size: size of the data to write.
1027  */
1028 static ssize_t
1029 ds1685_rtc_sysfs_nvram_write(struct file *filp, struct kobject *kobj,
1030 			     struct bin_attribute *bin_attr, char *buf,
1031 			     loff_t pos, size_t size)
1032 {
1033 	struct platform_device *pdev =
1034 		to_platform_device(container_of(kobj, struct device, kobj));
1035 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1036 	ssize_t count;
1037 	unsigned long flags = 0;
1038 
1039 	spin_lock_irqsave(&rtc->lock, flags);
1040 	ds1685_rtc_switch_to_bank0(rtc);
1041 
1042 	/* Write NVRAM in time and bank0 registers. */
1043 	for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
1044 	     count++, size--)
1045 		if (count < NVRAM_SZ_TIME)
1046 			rtc->write(rtc, (NVRAM_TIME_BASE + pos++),
1047 				   *buf++);
1048 		else
1049 			rtc->write(rtc, (NVRAM_BANK0_BASE), *buf++);
1050 
1051 #ifndef CONFIG_RTC_DRV_DS1689
1052 	if (size > 0) {
1053 		ds1685_rtc_switch_to_bank1(rtc);
1054 
1055 #ifndef CONFIG_RTC_DRV_DS1685
1056 		/* Enable burst-mode on DS17x85/DS17x87 */
1057 		rtc->write(rtc, RTC_EXT_CTRL_4A,
1058 			   (rtc->read(rtc, RTC_EXT_CTRL_4A) |
1059 			    RTC_CTRL_4A_BME));
1060 
1061 		/* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
1062 		 * writing with burst-mode */
1063 		rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
1064 			   (pos - NVRAM_TOTAL_SZ_BANK0));
1065 #endif
1066 
1067 		/* Write NVRAM in bank1 registers. */
1068 		for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
1069 		     count++, size--) {
1070 #ifdef CONFIG_RTC_DRV_DS1685
1071 			/* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
1072 			 * before each read. */
1073 			rtc->write(rtc, RTC_BANK1_RAM_ADDR,
1074 				   (pos - NVRAM_TOTAL_SZ_BANK0));
1075 #endif
1076 			rtc->write(rtc, RTC_BANK1_RAM_DATA_PORT, *buf++);
1077 			pos++;
1078 		}
1079 
1080 #ifndef CONFIG_RTC_DRV_DS1685
1081 		/* Disable burst-mode on DS17x85/DS17x87 */
1082 		rtc->write(rtc, RTC_EXT_CTRL_4A,
1083 			   (rtc->read(rtc, RTC_EXT_CTRL_4A) &
1084 			    ~(RTC_CTRL_4A_BME)));
1085 #endif
1086 		ds1685_rtc_switch_to_bank0(rtc);
1087 	}
1088 #endif /* !CONFIG_RTC_DRV_DS1689 */
1089 	spin_unlock_irqrestore(&rtc->lock, flags);
1090 
1091 	return count;
1092 }
1093 
1094 /**
1095  * struct ds1685_rtc_sysfs_nvram_attr - sysfs attributes for rtc nvram.
1096  * @attr: nvram attributes.
1097  * @read: nvram read function.
1098  * @write: nvram write function.
1099  * @size: nvram total size (bank0 + extended).
1100  */
1101 static struct bin_attribute
1102 ds1685_rtc_sysfs_nvram_attr = {
1103 	.attr = {
1104 		.name = "nvram",
1105 		.mode = S_IRUGO | S_IWUSR,
1106 	},
1107 	.read = ds1685_rtc_sysfs_nvram_read,
1108 	.write = ds1685_rtc_sysfs_nvram_write,
1109 	.size = NVRAM_TOTAL_SZ
1110 };
1111 
1112 /**
1113  * ds1685_rtc_sysfs_battery_show - sysfs file for main battery status.
1114  * @dev: pointer to device structure.
1115  * @attr: pointer to device_attribute structure.
1116  * @buf: pointer to char array to hold the output.
1117  */
1118 static ssize_t
1119 ds1685_rtc_sysfs_battery_show(struct device *dev,
1120 			      struct device_attribute *attr, char *buf)
1121 {
1122 	struct platform_device *pdev = to_platform_device(dev);
1123 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1124 	u8 ctrld;
1125 
1126 	ctrld = rtc->read(rtc, RTC_CTRL_D);
1127 
1128 	return sprintf(buf, "%s\n",
1129 			(ctrld & RTC_CTRL_D_VRT) ? "ok" : "not ok or N/A");
1130 }
1131 static DEVICE_ATTR(battery, S_IRUGO, ds1685_rtc_sysfs_battery_show, NULL);
1132 
1133 /**
1134  * ds1685_rtc_sysfs_auxbatt_show - sysfs file for aux battery status.
1135  * @dev: pointer to device structure.
1136  * @attr: pointer to device_attribute structure.
1137  * @buf: pointer to char array to hold the output.
1138  */
1139 static ssize_t
1140 ds1685_rtc_sysfs_auxbatt_show(struct device *dev,
1141 			      struct device_attribute *attr, char *buf)
1142 {
1143 	struct platform_device *pdev = to_platform_device(dev);
1144 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1145 	u8 ctrl4a;
1146 
1147 	ds1685_rtc_switch_to_bank1(rtc);
1148 	ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
1149 	ds1685_rtc_switch_to_bank0(rtc);
1150 
1151 	return sprintf(buf, "%s\n",
1152 			(ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "not ok or N/A");
1153 }
1154 static DEVICE_ATTR(auxbatt, S_IRUGO, ds1685_rtc_sysfs_auxbatt_show, NULL);
1155 
1156 /**
1157  * ds1685_rtc_sysfs_serial_show - sysfs file for silicon serial number.
1158  * @dev: pointer to device structure.
1159  * @attr: pointer to device_attribute structure.
1160  * @buf: pointer to char array to hold the output.
1161  */
1162 static ssize_t
1163 ds1685_rtc_sysfs_serial_show(struct device *dev,
1164 			     struct device_attribute *attr, char *buf)
1165 {
1166 	struct platform_device *pdev = to_platform_device(dev);
1167 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1168 	u8 ssn[8];
1169 
1170 	ds1685_rtc_switch_to_bank1(rtc);
1171 	ds1685_rtc_get_ssn(rtc, ssn);
1172 	ds1685_rtc_switch_to_bank0(rtc);
1173 
1174 	return sprintf(buf, "%8phC\n", ssn);
1175 }
1176 static DEVICE_ATTR(serial, S_IRUGO, ds1685_rtc_sysfs_serial_show, NULL);
1177 
1178 /**
1179  * struct ds1685_rtc_sysfs_misc_attrs - list for misc RTC features.
1180  */
1181 static struct attribute*
1182 ds1685_rtc_sysfs_misc_attrs[] = {
1183 	&dev_attr_battery.attr,
1184 	&dev_attr_auxbatt.attr,
1185 	&dev_attr_serial.attr,
1186 	NULL,
1187 };
1188 
1189 /**
1190  * struct ds1685_rtc_sysfs_misc_grp - attr group for misc RTC features.
1191  */
1192 static const struct attribute_group
1193 ds1685_rtc_sysfs_misc_grp = {
1194 	.name = "misc",
1195 	.attrs = ds1685_rtc_sysfs_misc_attrs,
1196 };
1197 
1198 #ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1199 /**
1200  * struct ds1685_rtc_ctrl_regs.
1201  * @name: char pointer for the bit name.
1202  * @reg: control register the bit is in.
1203  * @bit: the bit's offset in the register.
1204  */
1205 struct ds1685_rtc_ctrl_regs {
1206 	const char *name;
1207 	const u8 reg;
1208 	const u8 bit;
1209 };
1210 
1211 /*
1212  * Ctrl register bit lookup table.
1213  */
1214 static const struct ds1685_rtc_ctrl_regs
1215 ds1685_ctrl_regs_table[] = {
1216 	{ "uip",  RTC_CTRL_A,      RTC_CTRL_A_UIP   },
1217 	{ "dv2",  RTC_CTRL_A,      RTC_CTRL_A_DV2   },
1218 	{ "dv1",  RTC_CTRL_A,      RTC_CTRL_A_DV1   },
1219 	{ "dv0",  RTC_CTRL_A,      RTC_CTRL_A_DV0   },
1220 	{ "rs3",  RTC_CTRL_A,      RTC_CTRL_A_RS3   },
1221 	{ "rs2",  RTC_CTRL_A,      RTC_CTRL_A_RS2   },
1222 	{ "rs1",  RTC_CTRL_A,      RTC_CTRL_A_RS1   },
1223 	{ "rs0",  RTC_CTRL_A,      RTC_CTRL_A_RS0   },
1224 	{ "set",  RTC_CTRL_B,      RTC_CTRL_B_SET   },
1225 	{ "pie",  RTC_CTRL_B,      RTC_CTRL_B_PIE   },
1226 	{ "aie",  RTC_CTRL_B,      RTC_CTRL_B_AIE   },
1227 	{ "uie",  RTC_CTRL_B,      RTC_CTRL_B_UIE   },
1228 	{ "sqwe", RTC_CTRL_B,      RTC_CTRL_B_SQWE  },
1229 	{ "dm",   RTC_CTRL_B,      RTC_CTRL_B_DM    },
1230 	{ "2412", RTC_CTRL_B,      RTC_CTRL_B_2412  },
1231 	{ "dse",  RTC_CTRL_B,      RTC_CTRL_B_DSE   },
1232 	{ "irqf", RTC_CTRL_C,      RTC_CTRL_C_IRQF  },
1233 	{ "pf",   RTC_CTRL_C,      RTC_CTRL_C_PF    },
1234 	{ "af",   RTC_CTRL_C,      RTC_CTRL_C_AF    },
1235 	{ "uf",   RTC_CTRL_C,      RTC_CTRL_C_UF    },
1236 	{ "vrt",  RTC_CTRL_D,      RTC_CTRL_D_VRT   },
1237 	{ "vrt2", RTC_EXT_CTRL_4A, RTC_CTRL_4A_VRT2 },
1238 	{ "incr", RTC_EXT_CTRL_4A, RTC_CTRL_4A_INCR },
1239 	{ "pab",  RTC_EXT_CTRL_4A, RTC_CTRL_4A_PAB  },
1240 	{ "rf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_RF   },
1241 	{ "wf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_WF   },
1242 	{ "kf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_KF   },
1243 #if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1244 	{ "bme",  RTC_EXT_CTRL_4A, RTC_CTRL_4A_BME  },
1245 #endif
1246 	{ "abe",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_ABE  },
1247 	{ "e32k", RTC_EXT_CTRL_4B, RTC_CTRL_4B_E32K },
1248 	{ "cs",   RTC_EXT_CTRL_4B, RTC_CTRL_4B_CS   },
1249 	{ "rce",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_RCE  },
1250 	{ "prs",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_PRS  },
1251 	{ "rie",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_RIE  },
1252 	{ "wie",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_WIE  },
1253 	{ "kse",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_KSE  },
1254 	{ NULL,   0,               0                },
1255 };
1256 
1257 /**
1258  * ds1685_rtc_sysfs_ctrl_regs_lookup - ctrl register bit lookup function.
1259  * @name: ctrl register bit to look up in ds1685_ctrl_regs_table.
1260  */
1261 static const struct ds1685_rtc_ctrl_regs*
1262 ds1685_rtc_sysfs_ctrl_regs_lookup(const char *name)
1263 {
1264 	const struct ds1685_rtc_ctrl_regs *p = ds1685_ctrl_regs_table;
1265 
1266 	for (; p->name != NULL; ++p)
1267 		if (strcmp(p->name, name) == 0)
1268 			return p;
1269 
1270 	return NULL;
1271 }
1272 
1273 /**
1274  * ds1685_rtc_sysfs_ctrl_regs_show - reads a ctrl register bit via sysfs.
1275  * @dev: pointer to device structure.
1276  * @attr: pointer to device_attribute structure.
1277  * @buf: pointer to char array to hold the output.
1278  */
1279 static ssize_t
1280 ds1685_rtc_sysfs_ctrl_regs_show(struct device *dev,
1281 				struct device_attribute *attr, char *buf)
1282 {
1283 	u8 tmp;
1284 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1285 	const struct ds1685_rtc_ctrl_regs *reg_info =
1286 		ds1685_rtc_sysfs_ctrl_regs_lookup(attr->attr.name);
1287 
1288 	/* Make sure we actually matched something. */
1289 	if (!reg_info)
1290 		return -EINVAL;
1291 
1292 	/* No spinlock during a read -- mutex is already held. */
1293 	ds1685_rtc_switch_to_bank1(rtc);
1294 	tmp = rtc->read(rtc, reg_info->reg) & reg_info->bit;
1295 	ds1685_rtc_switch_to_bank0(rtc);
1296 
1297 	return sprintf(buf, "%d\n", (tmp ? 1 : 0));
1298 }
1299 
1300 /**
1301  * ds1685_rtc_sysfs_ctrl_regs_store - writes a ctrl register bit via sysfs.
1302  * @dev: pointer to device structure.
1303  * @attr: pointer to device_attribute structure.
1304  * @buf: pointer to char array to hold the output.
1305  * @count: number of bytes written.
1306  */
1307 static ssize_t
1308 ds1685_rtc_sysfs_ctrl_regs_store(struct device *dev,
1309 				 struct device_attribute *attr,
1310 				 const char *buf, size_t count)
1311 {
1312 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1313 	u8 reg = 0, bit = 0, tmp;
1314 	unsigned long flags;
1315 	long int val = 0;
1316 	const struct ds1685_rtc_ctrl_regs *reg_info =
1317 		ds1685_rtc_sysfs_ctrl_regs_lookup(attr->attr.name);
1318 
1319 	/* We only accept numbers. */
1320 	if (kstrtol(buf, 10, &val) < 0)
1321 		return -EINVAL;
1322 
1323 	/* bits are binary, 0 or 1 only. */
1324 	if ((val != 0) && (val != 1))
1325 		return -ERANGE;
1326 
1327 	/* Make sure we actually matched something. */
1328 	if (!reg_info)
1329 		return -EINVAL;
1330 
1331 	reg = reg_info->reg;
1332 	bit = reg_info->bit;
1333 
1334 	/* Safe to spinlock during a write. */
1335 	ds1685_rtc_begin_ctrl_access(rtc, &flags);
1336 	tmp = rtc->read(rtc, reg);
1337 	rtc->write(rtc, reg, (val ? (tmp | bit) : (tmp & ~(bit))));
1338 	ds1685_rtc_end_ctrl_access(rtc, flags);
1339 
1340 	return count;
1341 }
1342 
1343 /**
1344  * DS1685_RTC_SYSFS_CTRL_REG_RO - device_attribute for read-only register bit.
1345  * @bit: bit to read.
1346  */
1347 #define DS1685_RTC_SYSFS_CTRL_REG_RO(bit)				\
1348 	static DEVICE_ATTR(bit, S_IRUGO,				\
1349 	ds1685_rtc_sysfs_ctrl_regs_show, NULL)
1350 
1351 /**
1352  * DS1685_RTC_SYSFS_CTRL_REG_RW - device_attribute for read-write register bit.
1353  * @bit: bit to read or write.
1354  */
1355 #define DS1685_RTC_SYSFS_CTRL_REG_RW(bit)				\
1356 	static DEVICE_ATTR(bit, S_IRUGO | S_IWUSR,			\
1357 	ds1685_rtc_sysfs_ctrl_regs_show,				\
1358 	ds1685_rtc_sysfs_ctrl_regs_store)
1359 
1360 /*
1361  * Control Register A bits.
1362  */
1363 DS1685_RTC_SYSFS_CTRL_REG_RO(uip);
1364 DS1685_RTC_SYSFS_CTRL_REG_RW(dv2);
1365 DS1685_RTC_SYSFS_CTRL_REG_RW(dv1);
1366 DS1685_RTC_SYSFS_CTRL_REG_RO(dv0);
1367 DS1685_RTC_SYSFS_CTRL_REG_RW(rs3);
1368 DS1685_RTC_SYSFS_CTRL_REG_RW(rs2);
1369 DS1685_RTC_SYSFS_CTRL_REG_RW(rs1);
1370 DS1685_RTC_SYSFS_CTRL_REG_RW(rs0);
1371 
1372 static struct attribute*
1373 ds1685_rtc_sysfs_ctrla_attrs[] = {
1374 	&dev_attr_uip.attr,
1375 	&dev_attr_dv2.attr,
1376 	&dev_attr_dv1.attr,
1377 	&dev_attr_dv0.attr,
1378 	&dev_attr_rs3.attr,
1379 	&dev_attr_rs2.attr,
1380 	&dev_attr_rs1.attr,
1381 	&dev_attr_rs0.attr,
1382 	NULL,
1383 };
1384 
1385 static const struct attribute_group
1386 ds1685_rtc_sysfs_ctrla_grp = {
1387 	.name = "ctrla",
1388 	.attrs = ds1685_rtc_sysfs_ctrla_attrs,
1389 };
1390 
1391 
1392 /*
1393  * Control Register B bits.
1394  */
1395 DS1685_RTC_SYSFS_CTRL_REG_RO(set);
1396 DS1685_RTC_SYSFS_CTRL_REG_RW(pie);
1397 DS1685_RTC_SYSFS_CTRL_REG_RW(aie);
1398 DS1685_RTC_SYSFS_CTRL_REG_RW(uie);
1399 DS1685_RTC_SYSFS_CTRL_REG_RW(sqwe);
1400 DS1685_RTC_SYSFS_CTRL_REG_RO(dm);
1401 DS1685_RTC_SYSFS_CTRL_REG_RO(2412);
1402 DS1685_RTC_SYSFS_CTRL_REG_RO(dse);
1403 
1404 static struct attribute*
1405 ds1685_rtc_sysfs_ctrlb_attrs[] = {
1406 	&dev_attr_set.attr,
1407 	&dev_attr_pie.attr,
1408 	&dev_attr_aie.attr,
1409 	&dev_attr_uie.attr,
1410 	&dev_attr_sqwe.attr,
1411 	&dev_attr_dm.attr,
1412 	&dev_attr_2412.attr,
1413 	&dev_attr_dse.attr,
1414 	NULL,
1415 };
1416 
1417 static const struct attribute_group
1418 ds1685_rtc_sysfs_ctrlb_grp = {
1419 	.name = "ctrlb",
1420 	.attrs = ds1685_rtc_sysfs_ctrlb_attrs,
1421 };
1422 
1423 /*
1424  * Control Register C bits.
1425  *
1426  * Reading Control C clears these bits!  Reading them individually can
1427  * possibly cause an interrupt to be missed.  Use the /proc interface
1428  * to see all the bits in this register simultaneously.
1429  */
1430 DS1685_RTC_SYSFS_CTRL_REG_RO(irqf);
1431 DS1685_RTC_SYSFS_CTRL_REG_RO(pf);
1432 DS1685_RTC_SYSFS_CTRL_REG_RO(af);
1433 DS1685_RTC_SYSFS_CTRL_REG_RO(uf);
1434 
1435 static struct attribute*
1436 ds1685_rtc_sysfs_ctrlc_attrs[] = {
1437 	&dev_attr_irqf.attr,
1438 	&dev_attr_pf.attr,
1439 	&dev_attr_af.attr,
1440 	&dev_attr_uf.attr,
1441 	NULL,
1442 };
1443 
1444 static const struct attribute_group
1445 ds1685_rtc_sysfs_ctrlc_grp = {
1446 	.name = "ctrlc",
1447 	.attrs = ds1685_rtc_sysfs_ctrlc_attrs,
1448 };
1449 
1450 /*
1451  * Control Register D bits.
1452  */
1453 DS1685_RTC_SYSFS_CTRL_REG_RO(vrt);
1454 
1455 static struct attribute*
1456 ds1685_rtc_sysfs_ctrld_attrs[] = {
1457 	&dev_attr_vrt.attr,
1458 	NULL,
1459 };
1460 
1461 static const struct attribute_group
1462 ds1685_rtc_sysfs_ctrld_grp = {
1463 	.name = "ctrld",
1464 	.attrs = ds1685_rtc_sysfs_ctrld_attrs,
1465 };
1466 
1467 /*
1468  * Control Register 4A bits.
1469  */
1470 DS1685_RTC_SYSFS_CTRL_REG_RO(vrt2);
1471 DS1685_RTC_SYSFS_CTRL_REG_RO(incr);
1472 DS1685_RTC_SYSFS_CTRL_REG_RW(pab);
1473 DS1685_RTC_SYSFS_CTRL_REG_RW(rf);
1474 DS1685_RTC_SYSFS_CTRL_REG_RW(wf);
1475 DS1685_RTC_SYSFS_CTRL_REG_RW(kf);
1476 #if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1477 DS1685_RTC_SYSFS_CTRL_REG_RO(bme);
1478 #endif
1479 
1480 static struct attribute*
1481 ds1685_rtc_sysfs_ctrl4a_attrs[] = {
1482 	&dev_attr_vrt2.attr,
1483 	&dev_attr_incr.attr,
1484 	&dev_attr_pab.attr,
1485 	&dev_attr_rf.attr,
1486 	&dev_attr_wf.attr,
1487 	&dev_attr_kf.attr,
1488 #if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1489 	&dev_attr_bme.attr,
1490 #endif
1491 	NULL,
1492 };
1493 
1494 static const struct attribute_group
1495 ds1685_rtc_sysfs_ctrl4a_grp = {
1496 	.name = "ctrl4a",
1497 	.attrs = ds1685_rtc_sysfs_ctrl4a_attrs,
1498 };
1499 
1500 /*
1501  * Control Register 4B bits.
1502  */
1503 DS1685_RTC_SYSFS_CTRL_REG_RW(abe);
1504 DS1685_RTC_SYSFS_CTRL_REG_RW(e32k);
1505 DS1685_RTC_SYSFS_CTRL_REG_RO(cs);
1506 DS1685_RTC_SYSFS_CTRL_REG_RW(rce);
1507 DS1685_RTC_SYSFS_CTRL_REG_RW(prs);
1508 DS1685_RTC_SYSFS_CTRL_REG_RW(rie);
1509 DS1685_RTC_SYSFS_CTRL_REG_RW(wie);
1510 DS1685_RTC_SYSFS_CTRL_REG_RW(kse);
1511 
1512 static struct attribute*
1513 ds1685_rtc_sysfs_ctrl4b_attrs[] = {
1514 	&dev_attr_abe.attr,
1515 	&dev_attr_e32k.attr,
1516 	&dev_attr_cs.attr,
1517 	&dev_attr_rce.attr,
1518 	&dev_attr_prs.attr,
1519 	&dev_attr_rie.attr,
1520 	&dev_attr_wie.attr,
1521 	&dev_attr_kse.attr,
1522 	NULL,
1523 };
1524 
1525 static const struct attribute_group
1526 ds1685_rtc_sysfs_ctrl4b_grp = {
1527 	.name = "ctrl4b",
1528 	.attrs = ds1685_rtc_sysfs_ctrl4b_attrs,
1529 };
1530 
1531 
1532 /**
1533  * struct ds1685_rtc_ctrl_regs.
1534  * @name: char pointer for the bit name.
1535  * @reg: control register the bit is in.
1536  * @bit: the bit's offset in the register.
1537  */
1538 struct ds1685_rtc_time_regs {
1539 	const char *name;
1540 	const u8 reg;
1541 	const u8 mask;
1542 	const u8 min;
1543 	const u8 max;
1544 };
1545 
1546 /*
1547  * Time/Date register lookup tables.
1548  */
1549 static const struct ds1685_rtc_time_regs
1550 ds1685_time_regs_bcd_table[] = {
1551 	{ "seconds",       RTC_SECS,       RTC_SECS_BCD_MASK,   0, 59 },
1552 	{ "minutes",       RTC_MINS,       RTC_MINS_BCD_MASK,   0, 59 },
1553 	{ "hours",         RTC_HRS,        RTC_HRS_24_BCD_MASK, 0, 23 },
1554 	{ "wday",          RTC_WDAY,       RTC_WDAY_MASK,       1,  7 },
1555 	{ "mday",          RTC_MDAY,       RTC_MDAY_BCD_MASK,   1, 31 },
1556 	{ "month",         RTC_MONTH,      RTC_MONTH_BCD_MASK,  1, 12 },
1557 	{ "year",          RTC_YEAR,       RTC_YEAR_BCD_MASK,   0, 99 },
1558 	{ "century",       RTC_CENTURY,    RTC_CENTURY_MASK,    0, 99 },
1559 	{ "alarm_seconds", RTC_SECS_ALARM, RTC_SECS_BCD_MASK,   0, 59 },
1560 	{ "alarm_minutes", RTC_MINS_ALARM, RTC_MINS_BCD_MASK,   0, 59 },
1561 	{ "alarm_hours",   RTC_HRS_ALARM,  RTC_HRS_24_BCD_MASK, 0, 23 },
1562 	{ "alarm_mday",    RTC_MDAY_ALARM, RTC_MDAY_ALARM_MASK, 1, 31 },
1563 	{ NULL,            0,              0,                   0,  0 },
1564 };
1565 
1566 static const struct ds1685_rtc_time_regs
1567 ds1685_time_regs_bin_table[] = {
1568 	{ "seconds",       RTC_SECS,       RTC_SECS_BIN_MASK,   0x00, 0x3b },
1569 	{ "minutes",       RTC_MINS,       RTC_MINS_BIN_MASK,   0x00, 0x3b },
1570 	{ "hours",         RTC_HRS,        RTC_HRS_24_BIN_MASK, 0x00, 0x17 },
1571 	{ "wday",          RTC_WDAY,       RTC_WDAY_MASK,       0x01, 0x07 },
1572 	{ "mday",          RTC_MDAY,       RTC_MDAY_BIN_MASK,   0x01, 0x1f },
1573 	{ "month",         RTC_MONTH,      RTC_MONTH_BIN_MASK,  0x01, 0x0c },
1574 	{ "year",          RTC_YEAR,       RTC_YEAR_BIN_MASK,   0x00, 0x63 },
1575 	{ "century",       RTC_CENTURY,    RTC_CENTURY_MASK,    0x00, 0x63 },
1576 	{ "alarm_seconds", RTC_SECS_ALARM, RTC_SECS_BIN_MASK,   0x00, 0x3b },
1577 	{ "alarm_minutes", RTC_MINS_ALARM, RTC_MINS_BIN_MASK,   0x00, 0x3b },
1578 	{ "alarm_hours",   RTC_HRS_ALARM,  RTC_HRS_24_BIN_MASK, 0x00, 0x17 },
1579 	{ "alarm_mday",    RTC_MDAY_ALARM, RTC_MDAY_ALARM_MASK, 0x01, 0x1f },
1580 	{ NULL,            0,              0,                   0x00, 0x00 },
1581 };
1582 
1583 /**
1584  * ds1685_rtc_sysfs_time_regs_bcd_lookup - time/date reg bit lookup function.
1585  * @name: register bit to look up in ds1685_time_regs_bcd_table.
1586  */
1587 static const struct ds1685_rtc_time_regs*
1588 ds1685_rtc_sysfs_time_regs_lookup(const char *name, bool bcd_mode)
1589 {
1590 	const struct ds1685_rtc_time_regs *p;
1591 
1592 	if (bcd_mode)
1593 		p = ds1685_time_regs_bcd_table;
1594 	else
1595 		p = ds1685_time_regs_bin_table;
1596 
1597 	for (; p->name != NULL; ++p)
1598 		if (strcmp(p->name, name) == 0)
1599 			return p;
1600 
1601 	return NULL;
1602 }
1603 
1604 /**
1605  * ds1685_rtc_sysfs_time_regs_show - reads a time/date register via sysfs.
1606  * @dev: pointer to device structure.
1607  * @attr: pointer to device_attribute structure.
1608  * @buf: pointer to char array to hold the output.
1609  */
1610 static ssize_t
1611 ds1685_rtc_sysfs_time_regs_show(struct device *dev,
1612 				struct device_attribute *attr, char *buf)
1613 {
1614 	u8 tmp;
1615 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1616 	const struct ds1685_rtc_time_regs *bcd_reg_info =
1617 		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, true);
1618 	const struct ds1685_rtc_time_regs *bin_reg_info =
1619 		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, false);
1620 
1621 	/* Make sure we actually matched something. */
1622 	if (!bcd_reg_info || !bin_reg_info)
1623 		return -EINVAL;
1624 
1625 	/* bcd_reg_info->reg == bin_reg_info->reg. */
1626 	ds1685_rtc_begin_data_access(rtc);
1627 	tmp = rtc->read(rtc, bcd_reg_info->reg);
1628 	ds1685_rtc_end_data_access(rtc);
1629 
1630 	tmp = ds1685_rtc_bcd2bin(rtc, tmp, bcd_reg_info->mask,
1631 				 bin_reg_info->mask);
1632 
1633 	return sprintf(buf, "%d\n", tmp);
1634 }
1635 
1636 /**
1637  * ds1685_rtc_sysfs_time_regs_store - writes a time/date register via sysfs.
1638  * @dev: pointer to device structure.
1639  * @attr: pointer to device_attribute structure.
1640  * @buf: pointer to char array to hold the output.
1641  * @count: number of bytes written.
1642  */
1643 static ssize_t
1644 ds1685_rtc_sysfs_time_regs_store(struct device *dev,
1645 				 struct device_attribute *attr,
1646 				 const char *buf, size_t count)
1647 {
1648 	long int val = 0;
1649 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1650 	const struct ds1685_rtc_time_regs *bcd_reg_info =
1651 		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, true);
1652 	const struct ds1685_rtc_time_regs *bin_reg_info =
1653 		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, false);
1654 
1655 	/* We only accept numbers. */
1656 	if (kstrtol(buf, 10, &val) < 0)
1657 		return -EINVAL;
1658 
1659 	/* Make sure we actually matched something. */
1660 	if (!bcd_reg_info || !bin_reg_info)
1661 		return -EINVAL;
1662 
1663 	/* Check for a valid range. */
1664 	if (rtc->bcd_mode) {
1665 		if ((val < bcd_reg_info->min) || (val > bcd_reg_info->max))
1666 			return -ERANGE;
1667 	} else {
1668 		if ((val < bin_reg_info->min) || (val > bin_reg_info->max))
1669 			return -ERANGE;
1670 	}
1671 
1672 	val = ds1685_rtc_bin2bcd(rtc, val, bin_reg_info->mask,
1673 				 bcd_reg_info->mask);
1674 
1675 	/* bcd_reg_info->reg == bin_reg_info->reg. */
1676 	ds1685_rtc_begin_data_access(rtc);
1677 	rtc->write(rtc, bcd_reg_info->reg, val);
1678 	ds1685_rtc_end_data_access(rtc);
1679 
1680 	return count;
1681 }
1682 
1683 /**
1684  * DS1685_RTC_SYSFS_REG_RW - device_attribute for a read-write time register.
1685  * @reg: time/date register to read or write.
1686  */
1687 #define DS1685_RTC_SYSFS_TIME_REG_RW(reg)				\
1688 	static DEVICE_ATTR(reg, S_IRUGO | S_IWUSR,			\
1689 	ds1685_rtc_sysfs_time_regs_show,				\
1690 	ds1685_rtc_sysfs_time_regs_store)
1691 
1692 /*
1693  * Time/Date Register bits.
1694  */
1695 DS1685_RTC_SYSFS_TIME_REG_RW(seconds);
1696 DS1685_RTC_SYSFS_TIME_REG_RW(minutes);
1697 DS1685_RTC_SYSFS_TIME_REG_RW(hours);
1698 DS1685_RTC_SYSFS_TIME_REG_RW(wday);
1699 DS1685_RTC_SYSFS_TIME_REG_RW(mday);
1700 DS1685_RTC_SYSFS_TIME_REG_RW(month);
1701 DS1685_RTC_SYSFS_TIME_REG_RW(year);
1702 DS1685_RTC_SYSFS_TIME_REG_RW(century);
1703 DS1685_RTC_SYSFS_TIME_REG_RW(alarm_seconds);
1704 DS1685_RTC_SYSFS_TIME_REG_RW(alarm_minutes);
1705 DS1685_RTC_SYSFS_TIME_REG_RW(alarm_hours);
1706 DS1685_RTC_SYSFS_TIME_REG_RW(alarm_mday);
1707 
1708 static struct attribute*
1709 ds1685_rtc_sysfs_time_attrs[] = {
1710 	&dev_attr_seconds.attr,
1711 	&dev_attr_minutes.attr,
1712 	&dev_attr_hours.attr,
1713 	&dev_attr_wday.attr,
1714 	&dev_attr_mday.attr,
1715 	&dev_attr_month.attr,
1716 	&dev_attr_year.attr,
1717 	&dev_attr_century.attr,
1718 	NULL,
1719 };
1720 
1721 static const struct attribute_group
1722 ds1685_rtc_sysfs_time_grp = {
1723 	.name = "datetime",
1724 	.attrs = ds1685_rtc_sysfs_time_attrs,
1725 };
1726 
1727 static struct attribute*
1728 ds1685_rtc_sysfs_alarm_attrs[] = {
1729 	&dev_attr_alarm_seconds.attr,
1730 	&dev_attr_alarm_minutes.attr,
1731 	&dev_attr_alarm_hours.attr,
1732 	&dev_attr_alarm_mday.attr,
1733 	NULL,
1734 };
1735 
1736 static const struct attribute_group
1737 ds1685_rtc_sysfs_alarm_grp = {
1738 	.name = "alarm",
1739 	.attrs = ds1685_rtc_sysfs_alarm_attrs,
1740 };
1741 #endif /* CONFIG_RTC_DS1685_SYSFS_REGS */
1742 
1743 
1744 /**
1745  * ds1685_rtc_sysfs_register - register sysfs files.
1746  * @dev: pointer to device structure.
1747  */
1748 static int
1749 ds1685_rtc_sysfs_register(struct device *dev)
1750 {
1751 	int ret = 0;
1752 
1753 	sysfs_bin_attr_init(&ds1685_rtc_sysfs_nvram_attr);
1754 	ret = sysfs_create_bin_file(&dev->kobj, &ds1685_rtc_sysfs_nvram_attr);
1755 	if (ret)
1756 		return ret;
1757 
1758 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_misc_grp);
1759 	if (ret)
1760 		return ret;
1761 
1762 #ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1763 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrla_grp);
1764 	if (ret)
1765 		return ret;
1766 
1767 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlb_grp);
1768 	if (ret)
1769 		return ret;
1770 
1771 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlc_grp);
1772 	if (ret)
1773 		return ret;
1774 
1775 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrld_grp);
1776 	if (ret)
1777 		return ret;
1778 
1779 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4a_grp);
1780 	if (ret)
1781 		return ret;
1782 
1783 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4b_grp);
1784 	if (ret)
1785 		return ret;
1786 
1787 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_time_grp);
1788 	if (ret)
1789 		return ret;
1790 
1791 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_alarm_grp);
1792 	if (ret)
1793 		return ret;
1794 #endif
1795 	return 0;
1796 }
1797 
1798 /**
1799  * ds1685_rtc_sysfs_unregister - unregister sysfs files.
1800  * @dev: pointer to device structure.
1801  */
1802 static int
1803 ds1685_rtc_sysfs_unregister(struct device *dev)
1804 {
1805 	sysfs_remove_bin_file(&dev->kobj, &ds1685_rtc_sysfs_nvram_attr);
1806 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_misc_grp);
1807 
1808 #ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1809 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrla_grp);
1810 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlb_grp);
1811 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlc_grp);
1812 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrld_grp);
1813 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4a_grp);
1814 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4b_grp);
1815 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_time_grp);
1816 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_alarm_grp);
1817 #endif
1818 
1819 	return 0;
1820 }
1821 #endif /* CONFIG_SYSFS */
1822 
1823 
1824 
1825 /* ----------------------------------------------------------------------- */
1826 /* Driver Probe/Removal */
1827 
1828 /**
1829  * ds1685_rtc_probe - initializes rtc driver.
1830  * @pdev: pointer to platform_device structure.
1831  */
1832 static int
1833 ds1685_rtc_probe(struct platform_device *pdev)
1834 {
1835 	struct rtc_device *rtc_dev;
1836 	struct resource *res;
1837 	struct ds1685_priv *rtc;
1838 	struct ds1685_rtc_platform_data *pdata;
1839 	u8 ctrla, ctrlb, hours;
1840 	unsigned char am_pm;
1841 	int ret = 0;
1842 
1843 	/* Get the platform data. */
1844 	pdata = (struct ds1685_rtc_platform_data *) pdev->dev.platform_data;
1845 	if (!pdata)
1846 		return -ENODEV;
1847 
1848 	/* Allocate memory for the rtc device. */
1849 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
1850 	if (!rtc)
1851 		return -ENOMEM;
1852 
1853 	/*
1854 	 * Allocate/setup any IORESOURCE_MEM resources, if required.  Not all
1855 	 * platforms put the RTC in an easy-access place.  Like the SGI Octane,
1856 	 * which attaches the RTC to a "ByteBus", hooked to a SuperIO chip
1857 	 * that sits behind the IOC3 PCI metadevice.
1858 	 */
1859 	if (pdata->alloc_io_resources) {
1860 		/* Get the platform resources. */
1861 		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1862 		if (!res)
1863 			return -ENXIO;
1864 		rtc->size = resource_size(res);
1865 
1866 		/* Request a memory region. */
1867 		/* XXX: mmio-only for now. */
1868 		if (!devm_request_mem_region(&pdev->dev, res->start, rtc->size,
1869 					     pdev->name))
1870 			return -EBUSY;
1871 
1872 		/*
1873 		 * Set the base address for the rtc, and ioremap its
1874 		 * registers.
1875 		 */
1876 		rtc->baseaddr = res->start;
1877 		rtc->regs = devm_ioremap(&pdev->dev, res->start, rtc->size);
1878 		if (!rtc->regs)
1879 			return -ENOMEM;
1880 	}
1881 	rtc->alloc_io_resources = pdata->alloc_io_resources;
1882 
1883 	/* Get the register step size. */
1884 	if (pdata->regstep > 0)
1885 		rtc->regstep = pdata->regstep;
1886 	else
1887 		rtc->regstep = 1;
1888 
1889 	/* Platform read function, else default if mmio setup */
1890 	if (pdata->plat_read)
1891 		rtc->read = pdata->plat_read;
1892 	else
1893 		if (pdata->alloc_io_resources)
1894 			rtc->read = ds1685_read;
1895 		else
1896 			return -ENXIO;
1897 
1898 	/* Platform write function, else default if mmio setup */
1899 	if (pdata->plat_write)
1900 		rtc->write = pdata->plat_write;
1901 	else
1902 		if (pdata->alloc_io_resources)
1903 			rtc->write = ds1685_write;
1904 		else
1905 			return -ENXIO;
1906 
1907 	/* Platform pre-shutdown function, if defined. */
1908 	if (pdata->plat_prepare_poweroff)
1909 		rtc->prepare_poweroff = pdata->plat_prepare_poweroff;
1910 
1911 	/* Platform wake_alarm function, if defined. */
1912 	if (pdata->plat_wake_alarm)
1913 		rtc->wake_alarm = pdata->plat_wake_alarm;
1914 
1915 	/* Platform post_ram_clear function, if defined. */
1916 	if (pdata->plat_post_ram_clear)
1917 		rtc->post_ram_clear = pdata->plat_post_ram_clear;
1918 
1919 	/* Init the spinlock, workqueue, & set the driver data. */
1920 	spin_lock_init(&rtc->lock);
1921 	INIT_WORK(&rtc->work, ds1685_rtc_work_queue);
1922 	platform_set_drvdata(pdev, rtc);
1923 
1924 	/* Turn the oscillator on if is not already on (DV1 = 1). */
1925 	ctrla = rtc->read(rtc, RTC_CTRL_A);
1926 	if (!(ctrla & RTC_CTRL_A_DV1))
1927 		ctrla |= RTC_CTRL_A_DV1;
1928 
1929 	/* Enable the countdown chain (DV2 = 0) */
1930 	ctrla &= ~(RTC_CTRL_A_DV2);
1931 
1932 	/* Clear RS3-RS0 in Control A. */
1933 	ctrla &= ~(RTC_CTRL_A_RS_MASK);
1934 
1935 	/*
1936 	 * All done with Control A.  Switch to Bank 1 for the remainder of
1937 	 * the RTC setup so we have access to the extended functions.
1938 	 */
1939 	ctrla |= RTC_CTRL_A_DV0;
1940 	rtc->write(rtc, RTC_CTRL_A, ctrla);
1941 
1942 	/* Default to 32768kHz output. */
1943 	rtc->write(rtc, RTC_EXT_CTRL_4B,
1944 		   (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_E32K));
1945 
1946 	/* Set the SET bit in Control B so we can do some housekeeping. */
1947 	rtc->write(rtc, RTC_CTRL_B,
1948 		   (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
1949 
1950 	/* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
1951 	while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
1952 		cpu_relax();
1953 
1954 	/*
1955 	 * If the platform supports BCD mode, then set DM=0 in Control B.
1956 	 * Otherwise, set DM=1 for BIN mode.
1957 	 */
1958 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
1959 	if (pdata->bcd_mode)
1960 		ctrlb &= ~(RTC_CTRL_B_DM);
1961 	else
1962 		ctrlb |= RTC_CTRL_B_DM;
1963 	rtc->bcd_mode = pdata->bcd_mode;
1964 
1965 	/*
1966 	 * Disable Daylight Savings Time (DSE = 0).
1967 	 * The RTC has hardcoded timezone information that is rendered
1968 	 * obselete.  We'll let the OS deal with DST settings instead.
1969 	 */
1970 	if (ctrlb & RTC_CTRL_B_DSE)
1971 		ctrlb &= ~(RTC_CTRL_B_DSE);
1972 
1973 	/* Force 24-hour mode (2412 = 1). */
1974 	if (!(ctrlb & RTC_CTRL_B_2412)) {
1975 		/* Reinitialize the time hours. */
1976 		hours = rtc->read(rtc, RTC_HRS);
1977 		am_pm = hours & RTC_HRS_AMPM_MASK;
1978 		hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
1979 					   RTC_HRS_12_BIN_MASK);
1980 		hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
1981 
1982 		/* Enable 24-hour mode. */
1983 		ctrlb |= RTC_CTRL_B_2412;
1984 
1985 		/* Write back to Control B, including DM & DSE bits. */
1986 		rtc->write(rtc, RTC_CTRL_B, ctrlb);
1987 
1988 		/* Write the time hours back. */
1989 		rtc->write(rtc, RTC_HRS,
1990 			   ds1685_rtc_bin2bcd(rtc, hours,
1991 					      RTC_HRS_24_BIN_MASK,
1992 					      RTC_HRS_24_BCD_MASK));
1993 
1994 		/* Reinitialize the alarm hours. */
1995 		hours = rtc->read(rtc, RTC_HRS_ALARM);
1996 		am_pm = hours & RTC_HRS_AMPM_MASK;
1997 		hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
1998 					   RTC_HRS_12_BIN_MASK);
1999 		hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
2000 
2001 		/* Write the alarm hours back. */
2002 		rtc->write(rtc, RTC_HRS_ALARM,
2003 			   ds1685_rtc_bin2bcd(rtc, hours,
2004 					      RTC_HRS_24_BIN_MASK,
2005 					      RTC_HRS_24_BCD_MASK));
2006 	} else {
2007 		/* 24-hour mode is already set, so write Control B back. */
2008 		rtc->write(rtc, RTC_CTRL_B, ctrlb);
2009 	}
2010 
2011 	/* Unset the SET bit in Control B so the RTC can update. */
2012 	rtc->write(rtc, RTC_CTRL_B,
2013 		   (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
2014 
2015 	/* Check the main battery. */
2016 	if (!(rtc->read(rtc, RTC_CTRL_D) & RTC_CTRL_D_VRT))
2017 		dev_warn(&pdev->dev,
2018 			 "Main battery is exhausted! RTC may be invalid!\n");
2019 
2020 	/* Check the auxillary battery.  It is optional. */
2021 	if (!(rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_VRT2))
2022 		dev_warn(&pdev->dev,
2023 			 "Aux battery is exhausted or not available.\n");
2024 
2025 	/* Read Ctrl B and clear PIE/AIE/UIE. */
2026 	rtc->write(rtc, RTC_CTRL_B,
2027 		   (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_PAU_MASK)));
2028 
2029 	/* Reading Ctrl C auto-clears PF/AF/UF. */
2030 	rtc->read(rtc, RTC_CTRL_C);
2031 
2032 	/* Read Ctrl 4B and clear RIE/WIE/KSE. */
2033 	rtc->write(rtc, RTC_EXT_CTRL_4B,
2034 		   (rtc->read(rtc, RTC_EXT_CTRL_4B) & ~(RTC_CTRL_4B_RWK_MASK)));
2035 
2036 	/* Clear RF/WF/KF in Ctrl 4A. */
2037 	rtc->write(rtc, RTC_EXT_CTRL_4A,
2038 		   (rtc->read(rtc, RTC_EXT_CTRL_4A) & ~(RTC_CTRL_4A_RWK_MASK)));
2039 
2040 	/*
2041 	 * Re-enable KSE to handle power button events.  We do not enable
2042 	 * WIE or RIE by default.
2043 	 */
2044 	rtc->write(rtc, RTC_EXT_CTRL_4B,
2045 		   (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_KSE));
2046 
2047 	/*
2048 	 * Fetch the IRQ and setup the interrupt handler.
2049 	 *
2050 	 * Not all platforms have the IRQF pin tied to something.  If not, the
2051 	 * RTC will still set the *IE / *F flags and raise IRQF in ctrlc, but
2052 	 * there won't be an automatic way of notifying the kernel about it,
2053 	 * unless ctrlc is explicitly polled.
2054 	 */
2055 	if (!pdata->no_irq) {
2056 		ret = platform_get_irq(pdev, 0);
2057 		if (ret > 0) {
2058 			rtc->irq_num = ret;
2059 
2060 			/* Request an IRQ. */
2061 			ret = devm_request_irq(&pdev->dev, rtc->irq_num,
2062 					       ds1685_rtc_irq_handler,
2063 					       IRQF_SHARED, pdev->name, pdev);
2064 
2065 			/* Check to see if something came back. */
2066 			if (unlikely(ret)) {
2067 				dev_warn(&pdev->dev,
2068 					 "RTC interrupt not available\n");
2069 				rtc->irq_num = 0;
2070 			}
2071 		} else
2072 			return ret;
2073 	}
2074 	rtc->no_irq = pdata->no_irq;
2075 
2076 	/* Setup complete. */
2077 	ds1685_rtc_switch_to_bank0(rtc);
2078 
2079 	/* Register the device as an RTC. */
2080 	rtc_dev = rtc_device_register(pdev->name, &pdev->dev,
2081 				      &ds1685_rtc_ops, THIS_MODULE);
2082 
2083 	/* Success? */
2084 	if (IS_ERR(rtc_dev))
2085 		return PTR_ERR(rtc_dev);
2086 
2087 	/* Maximum periodic rate is 8192Hz (0.122070ms). */
2088 	rtc_dev->max_user_freq = RTC_MAX_USER_FREQ;
2089 
2090 	/* See if the platform doesn't support UIE. */
2091 	if (pdata->uie_unsupported)
2092 		rtc_dev->uie_unsupported = 1;
2093 	rtc->uie_unsupported = pdata->uie_unsupported;
2094 
2095 	rtc->dev = rtc_dev;
2096 
2097 #ifdef CONFIG_SYSFS
2098 	ret = ds1685_rtc_sysfs_register(&pdev->dev);
2099 	if (ret)
2100 		rtc_device_unregister(rtc->dev);
2101 #endif
2102 
2103 	/* Done! */
2104 	return ret;
2105 }
2106 
2107 /**
2108  * ds1685_rtc_remove - removes rtc driver.
2109  * @pdev: pointer to platform_device structure.
2110  */
2111 static int
2112 ds1685_rtc_remove(struct platform_device *pdev)
2113 {
2114 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
2115 
2116 #ifdef CONFIG_SYSFS
2117 	ds1685_rtc_sysfs_unregister(&pdev->dev);
2118 #endif
2119 
2120 	rtc_device_unregister(rtc->dev);
2121 
2122 	/* Read Ctrl B and clear PIE/AIE/UIE. */
2123 	rtc->write(rtc, RTC_CTRL_B,
2124 		   (rtc->read(rtc, RTC_CTRL_B) &
2125 		    ~(RTC_CTRL_B_PAU_MASK)));
2126 
2127 	/* Reading Ctrl C auto-clears PF/AF/UF. */
2128 	rtc->read(rtc, RTC_CTRL_C);
2129 
2130 	/* Read Ctrl 4B and clear RIE/WIE/KSE. */
2131 	rtc->write(rtc, RTC_EXT_CTRL_4B,
2132 		   (rtc->read(rtc, RTC_EXT_CTRL_4B) &
2133 		    ~(RTC_CTRL_4B_RWK_MASK)));
2134 
2135 	/* Manually clear RF/WF/KF in Ctrl 4A. */
2136 	rtc->write(rtc, RTC_EXT_CTRL_4A,
2137 		   (rtc->read(rtc, RTC_EXT_CTRL_4A) &
2138 		    ~(RTC_CTRL_4A_RWK_MASK)));
2139 
2140 	cancel_work_sync(&rtc->work);
2141 
2142 	return 0;
2143 }
2144 
2145 /**
2146  * ds1685_rtc_driver - rtc driver properties.
2147  */
2148 static struct platform_driver ds1685_rtc_driver = {
2149 	.driver		= {
2150 		.name	= "rtc-ds1685",
2151 	},
2152 	.probe		= ds1685_rtc_probe,
2153 	.remove		= ds1685_rtc_remove,
2154 };
2155 module_platform_driver(ds1685_rtc_driver);
2156 /* ----------------------------------------------------------------------- */
2157 
2158 
2159 /* ----------------------------------------------------------------------- */
2160 /* Poweroff function */
2161 
2162 /**
2163  * ds1685_rtc_poweroff - uses the RTC chip to power the system off.
2164  * @pdev: pointer to platform_device structure.
2165  */
2166 void __noreturn
2167 ds1685_rtc_poweroff(struct platform_device *pdev)
2168 {
2169 	u8 ctrla, ctrl4a, ctrl4b;
2170 	struct ds1685_priv *rtc;
2171 
2172 	/* Check for valid RTC data, else, spin forever. */
2173 	if (unlikely(!pdev)) {
2174 		pr_emerg("platform device data not available, spinning forever ...\n");
2175 		while(1);
2176 		unreachable();
2177 	} else {
2178 		/* Get the rtc data. */
2179 		rtc = platform_get_drvdata(pdev);
2180 
2181 		/*
2182 		 * Disable our IRQ.  We're powering down, so we're not
2183 		 * going to worry about cleaning up.  Most of that should
2184 		 * have been taken care of by the shutdown scripts and this
2185 		 * is the final function call.
2186 		 */
2187 		if (!rtc->no_irq)
2188 			disable_irq_nosync(rtc->irq_num);
2189 
2190 		/* Oscillator must be on and the countdown chain enabled. */
2191 		ctrla = rtc->read(rtc, RTC_CTRL_A);
2192 		ctrla |= RTC_CTRL_A_DV1;
2193 		ctrla &= ~(RTC_CTRL_A_DV2);
2194 		rtc->write(rtc, RTC_CTRL_A, ctrla);
2195 
2196 		/*
2197 		 * Read Control 4A and check the status of the auxillary
2198 		 * battery.  This must be present and working (VRT2 = 1)
2199 		 * for wakeup and kickstart functionality to be useful.
2200 		 */
2201 		ds1685_rtc_switch_to_bank1(rtc);
2202 		ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
2203 		if (ctrl4a & RTC_CTRL_4A_VRT2) {
2204 			/* Clear all of the interrupt flags on Control 4A. */
2205 			ctrl4a &= ~(RTC_CTRL_4A_RWK_MASK);
2206 			rtc->write(rtc, RTC_EXT_CTRL_4A, ctrl4a);
2207 
2208 			/*
2209 			 * The auxillary battery is present and working.
2210 			 * Enable extended functions (ABE=1), enable
2211 			 * wake-up (WIE=1), and enable kickstart (KSE=1)
2212 			 * in Control 4B.
2213 			 */
2214 			ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
2215 			ctrl4b |= (RTC_CTRL_4B_ABE | RTC_CTRL_4B_WIE |
2216 				   RTC_CTRL_4B_KSE);
2217 			rtc->write(rtc, RTC_EXT_CTRL_4B, ctrl4b);
2218 		}
2219 
2220 		/* Set PAB to 1 in Control 4A to power the system down. */
2221 		dev_warn(&pdev->dev, "Powerdown.\n");
2222 		msleep(20);
2223 		rtc->write(rtc, RTC_EXT_CTRL_4A,
2224 			   (ctrl4a | RTC_CTRL_4A_PAB));
2225 
2226 		/* Spin ... we do not switch back to bank0. */
2227 		while(1);
2228 		unreachable();
2229 	}
2230 }
2231 EXPORT_SYMBOL(ds1685_rtc_poweroff);
2232 /* ----------------------------------------------------------------------- */
2233 
2234 
2235 MODULE_AUTHOR("Joshua Kinard <kumba@gentoo.org>");
2236 MODULE_AUTHOR("Matthias Fuchs <matthias.fuchs@esd-electronics.com>");
2237 MODULE_DESCRIPTION("Dallas/Maxim DS1685/DS1687-series RTC driver");
2238 MODULE_LICENSE("GPL");
2239 MODULE_ALIAS("platform:rtc-ds1685");
2240