xref: /openbmc/linux/drivers/rtc/rtc-ds1685.c (revision 4f3db074)
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 #define DRV_VERSION	"0.42.0"
36 
37 
38 /* ----------------------------------------------------------------------- */
39 /* Standard read/write functions if platform does not provide overrides */
40 
41 /**
42  * ds1685_read - read a value from an rtc register.
43  * @rtc: pointer to the ds1685 rtc structure.
44  * @reg: the register address to read.
45  */
46 static u8
47 ds1685_read(struct ds1685_priv *rtc, int reg)
48 {
49 	return readb((u8 __iomem *)rtc->regs +
50 		     (reg * rtc->regstep));
51 }
52 
53 /**
54  * ds1685_write - write a value to an rtc register.
55  * @rtc: pointer to the ds1685 rtc structure.
56  * @reg: the register address to write.
57  * @value: value to write to the register.
58  */
59 static void
60 ds1685_write(struct ds1685_priv *rtc, int reg, u8 value)
61 {
62 	writeb(value, ((u8 __iomem *)rtc->regs +
63 		       (reg * rtc->regstep)));
64 }
65 /* ----------------------------------------------------------------------- */
66 
67 
68 /* ----------------------------------------------------------------------- */
69 /* Inlined functions */
70 
71 /**
72  * ds1685_rtc_bcd2bin - bcd2bin wrapper in case platform doesn't support BCD.
73  * @rtc: pointer to the ds1685 rtc structure.
74  * @val: u8 time value to consider converting.
75  * @bcd_mask: u8 mask value if BCD mode is used.
76  * @bin_mask: u8 mask value if BIN mode is used.
77  *
78  * Returns the value, converted to BIN if originally in BCD and bcd_mode TRUE.
79  */
80 static inline u8
81 ds1685_rtc_bcd2bin(struct ds1685_priv *rtc, u8 val, u8 bcd_mask, u8 bin_mask)
82 {
83 	if (rtc->bcd_mode)
84 		return (bcd2bin(val) & bcd_mask);
85 
86 	return (val & bin_mask);
87 }
88 
89 /**
90  * ds1685_rtc_bin2bcd - bin2bcd wrapper in case platform doesn't support BCD.
91  * @rtc: pointer to the ds1685 rtc structure.
92  * @val: u8 time value to consider converting.
93  * @bin_mask: u8 mask value if BIN mode is used.
94  * @bcd_mask: u8 mask value if BCD mode is used.
95  *
96  * Returns the value, converted to BCD if originally in BIN and bcd_mode TRUE.
97  */
98 static inline u8
99 ds1685_rtc_bin2bcd(struct ds1685_priv *rtc, u8 val, u8 bin_mask, u8 bcd_mask)
100 {
101 	if (rtc->bcd_mode)
102 		return (bin2bcd(val) & bcd_mask);
103 
104 	return (val & bin_mask);
105 }
106 
107 /**
108  * ds1685_rtc_switch_to_bank0 - switch the rtc to bank 0.
109  * @rtc: pointer to the ds1685 rtc structure.
110  */
111 static inline void
112 ds1685_rtc_switch_to_bank0(struct ds1685_priv *rtc)
113 {
114 	rtc->write(rtc, RTC_CTRL_A,
115 		   (rtc->read(rtc, RTC_CTRL_A) & ~(RTC_CTRL_A_DV0)));
116 }
117 
118 /**
119  * ds1685_rtc_switch_to_bank1 - switch the rtc to bank 1.
120  * @rtc: pointer to the ds1685 rtc structure.
121  */
122 static inline void
123 ds1685_rtc_switch_to_bank1(struct ds1685_priv *rtc)
124 {
125 	rtc->write(rtc, RTC_CTRL_A,
126 		   (rtc->read(rtc, RTC_CTRL_A) | RTC_CTRL_A_DV0));
127 }
128 
129 /**
130  * ds1685_rtc_begin_data_access - prepare the rtc for data access.
131  * @rtc: pointer to the ds1685 rtc structure.
132  *
133  * This takes several steps to prepare the rtc for access to get/set time
134  * and alarm values from the rtc registers:
135  *  - Sets the SET bit in Control Register B.
136  *  - Reads Ext Control Register 4A and checks the INCR bit.
137  *  - If INCR is active, a short delay is added before Ext Control Register 4A
138  *    is read again in a loop until INCR is inactive.
139  *  - Switches the rtc to bank 1.  This allows access to all relevant
140  *    data for normal rtc operation, as bank 0 contains only the nvram.
141  */
142 static inline void
143 ds1685_rtc_begin_data_access(struct ds1685_priv *rtc)
144 {
145 	/* Set the SET bit in Ctrl B */
146 	rtc->write(rtc, RTC_CTRL_B,
147 		   (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
148 
149 	/* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
150 	while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
151 		cpu_relax();
152 
153 	/* Switch to Bank 1 */
154 	ds1685_rtc_switch_to_bank1(rtc);
155 }
156 
157 /**
158  * ds1685_rtc_end_data_access - end data access on the rtc.
159  * @rtc: pointer to the ds1685 rtc structure.
160  *
161  * This ends what was started by ds1685_rtc_begin_data_access:
162  *  - Switches the rtc back to bank 0.
163  *  - Clears the SET bit in Control Register B.
164  */
165 static inline void
166 ds1685_rtc_end_data_access(struct ds1685_priv *rtc)
167 {
168 	/* Switch back to Bank 0 */
169 	ds1685_rtc_switch_to_bank1(rtc);
170 
171 	/* Clear the SET bit in Ctrl B */
172 	rtc->write(rtc, RTC_CTRL_B,
173 		   (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
174 }
175 
176 /**
177  * ds1685_rtc_begin_ctrl_access - prepare the rtc for ctrl access.
178  * @rtc: pointer to the ds1685 rtc structure.
179  * @flags: irq flags variable for spin_lock_irqsave.
180  *
181  * This takes several steps to prepare the rtc for access to read just the
182  * control registers:
183  *  - Sets a spinlock on the rtc IRQ.
184  *  - Switches the rtc to bank 1.  This allows access to the two extended
185  *    control registers.
186  *
187  * Only use this where you are certain another lock will not be held.
188  */
189 static inline void
190 ds1685_rtc_begin_ctrl_access(struct ds1685_priv *rtc, unsigned long flags)
191 {
192 	spin_lock_irqsave(&rtc->lock, flags);
193 	ds1685_rtc_switch_to_bank1(rtc);
194 }
195 
196 /**
197  * ds1685_rtc_end_ctrl_access - end ctrl access on the rtc.
198  * @rtc: pointer to the ds1685 rtc structure.
199  * @flags: irq flags variable for spin_unlock_irqrestore.
200  *
201  * This ends what was started by ds1685_rtc_begin_ctrl_access:
202  *  - Switches the rtc back to bank 0.
203  *  - Unsets the spinlock on the rtc IRQ.
204  */
205 static inline void
206 ds1685_rtc_end_ctrl_access(struct ds1685_priv *rtc, unsigned long flags)
207 {
208 	ds1685_rtc_switch_to_bank0(rtc);
209 	spin_unlock_irqrestore(&rtc->lock, flags);
210 }
211 
212 /**
213  * ds1685_rtc_get_ssn - retrieve the silicon serial number.
214  * @rtc: pointer to the ds1685 rtc structure.
215  * @ssn: u8 array to hold the bits of the silicon serial number.
216  *
217  * This number starts at 0x40, and is 8-bytes long, ending at 0x47. The
218  * first byte is the model number, the next six bytes are the serial number
219  * digits, and the final byte is a CRC check byte.  Together, they form the
220  * silicon serial number.
221  *
222  * These values are stored in bank1, so ds1685_rtc_switch_to_bank1 must be
223  * called first before calling this function, else data will be read out of
224  * the bank0 NVRAM.  Be sure to call ds1685_rtc_switch_to_bank0 when done.
225  */
226 static inline void
227 ds1685_rtc_get_ssn(struct ds1685_priv *rtc, u8 *ssn)
228 {
229 	ssn[0] = rtc->read(rtc, RTC_BANK1_SSN_MODEL);
230 	ssn[1] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_1);
231 	ssn[2] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_2);
232 	ssn[3] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_3);
233 	ssn[4] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_4);
234 	ssn[5] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_5);
235 	ssn[6] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_6);
236 	ssn[7] = rtc->read(rtc, RTC_BANK1_SSN_CRC);
237 }
238 /* ----------------------------------------------------------------------- */
239 
240 
241 /* ----------------------------------------------------------------------- */
242 /* Read/Set Time & Alarm functions */
243 
244 /**
245  * ds1685_rtc_read_time - reads the time registers.
246  * @dev: pointer to device structure.
247  * @tm: pointer to rtc_time structure.
248  */
249 static int
250 ds1685_rtc_read_time(struct device *dev, struct rtc_time *tm)
251 {
252 	struct platform_device *pdev = to_platform_device(dev);
253 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
254 	u8 ctrlb, century;
255 	u8 seconds, minutes, hours, wday, mday, month, years;
256 
257 	/* Fetch the time info from the RTC registers. */
258 	ds1685_rtc_begin_data_access(rtc);
259 	seconds = rtc->read(rtc, RTC_SECS);
260 	minutes = rtc->read(rtc, RTC_MINS);
261 	hours   = rtc->read(rtc, RTC_HRS);
262 	wday    = rtc->read(rtc, RTC_WDAY);
263 	mday    = rtc->read(rtc, RTC_MDAY);
264 	month   = rtc->read(rtc, RTC_MONTH);
265 	years   = rtc->read(rtc, RTC_YEAR);
266 	century = rtc->read(rtc, RTC_CENTURY);
267 	ctrlb   = rtc->read(rtc, RTC_CTRL_B);
268 	ds1685_rtc_end_data_access(rtc);
269 
270 	/* bcd2bin if needed, perform fixups, and store to rtc_time. */
271 	years        = ds1685_rtc_bcd2bin(rtc, years, RTC_YEAR_BCD_MASK,
272 					  RTC_YEAR_BIN_MASK);
273 	century      = ds1685_rtc_bcd2bin(rtc, century, RTC_CENTURY_MASK,
274 					  RTC_CENTURY_MASK);
275 	tm->tm_sec   = ds1685_rtc_bcd2bin(rtc, seconds, RTC_SECS_BCD_MASK,
276 					  RTC_SECS_BIN_MASK);
277 	tm->tm_min   = ds1685_rtc_bcd2bin(rtc, minutes, RTC_MINS_BCD_MASK,
278 					  RTC_MINS_BIN_MASK);
279 	tm->tm_hour  = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_24_BCD_MASK,
280 					  RTC_HRS_24_BIN_MASK);
281 	tm->tm_wday  = (ds1685_rtc_bcd2bin(rtc, wday, RTC_WDAY_MASK,
282 					   RTC_WDAY_MASK) - 1);
283 	tm->tm_mday  = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
284 					  RTC_MDAY_BIN_MASK);
285 	tm->tm_mon   = (ds1685_rtc_bcd2bin(rtc, month, RTC_MONTH_BCD_MASK,
286 					   RTC_MONTH_BIN_MASK) - 1);
287 	tm->tm_year  = ((years + (century * 100)) - 1900);
288 	tm->tm_yday  = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
289 	tm->tm_isdst = 0; /* RTC has hardcoded timezone, so don't use. */
290 
291 	return rtc_valid_tm(tm);
292 }
293 
294 /**
295  * ds1685_rtc_set_time - sets the time registers.
296  * @dev: pointer to device structure.
297  * @tm: pointer to rtc_time structure.
298  */
299 static int
300 ds1685_rtc_set_time(struct device *dev, struct rtc_time *tm)
301 {
302 	struct platform_device *pdev = to_platform_device(dev);
303 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
304 	u8 ctrlb, seconds, minutes, hours, wday, mday, month, years, century;
305 
306 	/* Fetch the time info from rtc_time. */
307 	seconds = ds1685_rtc_bin2bcd(rtc, tm->tm_sec, RTC_SECS_BIN_MASK,
308 				     RTC_SECS_BCD_MASK);
309 	minutes = ds1685_rtc_bin2bcd(rtc, tm->tm_min, RTC_MINS_BIN_MASK,
310 				     RTC_MINS_BCD_MASK);
311 	hours   = ds1685_rtc_bin2bcd(rtc, tm->tm_hour, RTC_HRS_24_BIN_MASK,
312 				     RTC_HRS_24_BCD_MASK);
313 	wday    = ds1685_rtc_bin2bcd(rtc, (tm->tm_wday + 1), RTC_WDAY_MASK,
314 				     RTC_WDAY_MASK);
315 	mday    = ds1685_rtc_bin2bcd(rtc, tm->tm_mday, RTC_MDAY_BIN_MASK,
316 				     RTC_MDAY_BCD_MASK);
317 	month   = ds1685_rtc_bin2bcd(rtc, (tm->tm_mon + 1), RTC_MONTH_BIN_MASK,
318 				     RTC_MONTH_BCD_MASK);
319 	years   = ds1685_rtc_bin2bcd(rtc, (tm->tm_year % 100),
320 				     RTC_YEAR_BIN_MASK, RTC_YEAR_BCD_MASK);
321 	century = ds1685_rtc_bin2bcd(rtc, ((tm->tm_year + 1900) / 100),
322 				     RTC_CENTURY_MASK, RTC_CENTURY_MASK);
323 
324 	/*
325 	 * Perform Sanity Checks:
326 	 *   - Months: !> 12, Month Day != 0.
327 	 *   - Month Day !> Max days in current month.
328 	 *   - Hours !>= 24, Mins !>= 60, Secs !>= 60, & Weekday !> 7.
329 	 */
330 	if ((tm->tm_mon > 11) || (mday == 0))
331 		return -EDOM;
332 
333 	if (tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year))
334 		return -EDOM;
335 
336 	if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) ||
337 	    (tm->tm_sec >= 60)  || (wday > 7))
338 		return -EDOM;
339 
340 	/*
341 	 * Set the data mode to use and store the time values in the
342 	 * RTC registers.
343 	 */
344 	ds1685_rtc_begin_data_access(rtc);
345 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
346 	if (rtc->bcd_mode)
347 		ctrlb &= ~(RTC_CTRL_B_DM);
348 	else
349 		ctrlb |= RTC_CTRL_B_DM;
350 	rtc->write(rtc, RTC_CTRL_B, ctrlb);
351 	rtc->write(rtc, RTC_SECS, seconds);
352 	rtc->write(rtc, RTC_MINS, minutes);
353 	rtc->write(rtc, RTC_HRS, hours);
354 	rtc->write(rtc, RTC_WDAY, wday);
355 	rtc->write(rtc, RTC_MDAY, mday);
356 	rtc->write(rtc, RTC_MONTH, month);
357 	rtc->write(rtc, RTC_YEAR, years);
358 	rtc->write(rtc, RTC_CENTURY, century);
359 	ds1685_rtc_end_data_access(rtc);
360 
361 	return 0;
362 }
363 
364 /**
365  * ds1685_rtc_read_alarm - reads the alarm registers.
366  * @dev: pointer to device structure.
367  * @alrm: pointer to rtc_wkalrm structure.
368  *
369  * There are three primary alarm registers: seconds, minutes, and hours.
370  * A fourth alarm register for the month date is also available in bank1 for
371  * kickstart/wakeup features.  The DS1685/DS1687 manual states that a
372  * "don't care" value ranging from 0xc0 to 0xff may be written into one or
373  * more of the three alarm bytes to act as a wildcard value.  The fourth
374  * byte doesn't support a "don't care" value.
375  */
376 static int
377 ds1685_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
378 {
379 	struct platform_device *pdev = to_platform_device(dev);
380 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
381 	u8 seconds, minutes, hours, mday, ctrlb, ctrlc;
382 
383 	/* Fetch the alarm info from the RTC alarm registers. */
384 	ds1685_rtc_begin_data_access(rtc);
385 	seconds	= rtc->read(rtc, RTC_SECS_ALARM);
386 	minutes	= rtc->read(rtc, RTC_MINS_ALARM);
387 	hours	= rtc->read(rtc, RTC_HRS_ALARM);
388 	mday	= rtc->read(rtc, RTC_MDAY_ALARM);
389 	ctrlb	= rtc->read(rtc, RTC_CTRL_B);
390 	ctrlc	= rtc->read(rtc, RTC_CTRL_C);
391 	ds1685_rtc_end_data_access(rtc);
392 
393 	/* Check month date. */
394 	if (!(mday >= 1) && (mday <= 31))
395 		return -EDOM;
396 
397 	/*
398 	 * Check the three alarm bytes.
399 	 *
400 	 * The Linux RTC system doesn't support the "don't care" capability
401 	 * of this RTC chip.  We check for it anyways in case support is
402 	 * added in the future.
403 	 */
404 	if (unlikely(seconds >= 0xc0))
405 		alrm->time.tm_sec = -1;
406 	else
407 		alrm->time.tm_sec = ds1685_rtc_bcd2bin(rtc, seconds,
408 						       RTC_SECS_BCD_MASK,
409 						       RTC_SECS_BIN_MASK);
410 
411 	if (unlikely(minutes >= 0xc0))
412 		alrm->time.tm_min = -1;
413 	else
414 		alrm->time.tm_min = ds1685_rtc_bcd2bin(rtc, minutes,
415 						       RTC_MINS_BCD_MASK,
416 						       RTC_MINS_BIN_MASK);
417 
418 	if (unlikely(hours >= 0xc0))
419 		alrm->time.tm_hour = -1;
420 	else
421 		alrm->time.tm_hour = ds1685_rtc_bcd2bin(rtc, hours,
422 							RTC_HRS_24_BCD_MASK,
423 							RTC_HRS_24_BIN_MASK);
424 
425 	/* Write the data to rtc_wkalrm. */
426 	alrm->time.tm_mday = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
427 						RTC_MDAY_BIN_MASK);
428 	alrm->time.tm_mon = -1;
429 	alrm->time.tm_year = -1;
430 	alrm->time.tm_wday = -1;
431 	alrm->time.tm_yday = -1;
432 	alrm->time.tm_isdst = -1;
433 	alrm->enabled = !!(ctrlb & RTC_CTRL_B_AIE);
434 	alrm->pending = !!(ctrlc & RTC_CTRL_C_AF);
435 
436 	return 0;
437 }
438 
439 /**
440  * ds1685_rtc_set_alarm - sets the alarm in registers.
441  * @dev: pointer to device structure.
442  * @alrm: pointer to rtc_wkalrm structure.
443  */
444 static int
445 ds1685_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
446 {
447 	struct platform_device *pdev = to_platform_device(dev);
448 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
449 	u8 ctrlb, seconds, minutes, hours, mday;
450 
451 	/* Fetch the alarm info and convert to BCD. */
452 	seconds	= ds1685_rtc_bin2bcd(rtc, alrm->time.tm_sec,
453 				     RTC_SECS_BIN_MASK,
454 				     RTC_SECS_BCD_MASK);
455 	minutes	= ds1685_rtc_bin2bcd(rtc, alrm->time.tm_min,
456 				     RTC_MINS_BIN_MASK,
457 				     RTC_MINS_BCD_MASK);
458 	hours	= ds1685_rtc_bin2bcd(rtc, alrm->time.tm_hour,
459 				     RTC_HRS_24_BIN_MASK,
460 				     RTC_HRS_24_BCD_MASK);
461 	mday	= ds1685_rtc_bin2bcd(rtc, alrm->time.tm_mday,
462 				     RTC_MDAY_BIN_MASK,
463 				     RTC_MDAY_BCD_MASK);
464 
465 	/* Check the month date for validity. */
466 	if (!(mday >= 1) && (mday <= 31))
467 		return -EDOM;
468 
469 	/*
470 	 * Check the three alarm bytes.
471 	 *
472 	 * The Linux RTC system doesn't support the "don't care" capability
473 	 * of this RTC chip because rtc_valid_tm tries to validate every
474 	 * field, and we only support four fields.  We put the support
475 	 * here anyways for the future.
476 	 */
477 	if (unlikely(seconds >= 0xc0))
478 		seconds = 0xff;
479 
480 	if (unlikely(minutes >= 0xc0))
481 		minutes = 0xff;
482 
483 	if (unlikely(hours >= 0xc0))
484 		hours = 0xff;
485 
486 	alrm->time.tm_mon	= -1;
487 	alrm->time.tm_year	= -1;
488 	alrm->time.tm_wday	= -1;
489 	alrm->time.tm_yday	= -1;
490 	alrm->time.tm_isdst	= -1;
491 
492 	/* Disable the alarm interrupt first. */
493 	ds1685_rtc_begin_data_access(rtc);
494 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
495 	rtc->write(rtc, RTC_CTRL_B, (ctrlb & ~(RTC_CTRL_B_AIE)));
496 
497 	/* Read ctrlc to clear RTC_CTRL_C_AF. */
498 	rtc->read(rtc, RTC_CTRL_C);
499 
500 	/*
501 	 * Set the data mode to use and store the time values in the
502 	 * RTC registers.
503 	 */
504 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
505 	if (rtc->bcd_mode)
506 		ctrlb &= ~(RTC_CTRL_B_DM);
507 	else
508 		ctrlb |= RTC_CTRL_B_DM;
509 	rtc->write(rtc, RTC_CTRL_B, ctrlb);
510 	rtc->write(rtc, RTC_SECS_ALARM, seconds);
511 	rtc->write(rtc, RTC_MINS_ALARM, minutes);
512 	rtc->write(rtc, RTC_HRS_ALARM, hours);
513 	rtc->write(rtc, RTC_MDAY_ALARM, mday);
514 
515 	/* Re-enable the alarm if needed. */
516 	if (alrm->enabled) {
517 		ctrlb = rtc->read(rtc, RTC_CTRL_B);
518 		ctrlb |= RTC_CTRL_B_AIE;
519 		rtc->write(rtc, RTC_CTRL_B, ctrlb);
520 	}
521 
522 	/* Done! */
523 	ds1685_rtc_end_data_access(rtc);
524 
525 	return 0;
526 }
527 /* ----------------------------------------------------------------------- */
528 
529 
530 /* ----------------------------------------------------------------------- */
531 /* /dev/rtcX Interface functions */
532 
533 /**
534  * ds1685_rtc_alarm_irq_enable - replaces ioctl() RTC_AIE on/off.
535  * @dev: pointer to device structure.
536  * @enabled: flag indicating whether to enable or disable.
537  */
538 static int
539 ds1685_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
540 {
541 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
542 	unsigned long flags = 0;
543 
544 	/* Enable/disable the Alarm IRQ-Enable flag. */
545 	spin_lock_irqsave(&rtc->lock, flags);
546 
547 	/* Flip the requisite interrupt-enable bit. */
548 	if (enabled)
549 		rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) |
550 					     RTC_CTRL_B_AIE));
551 	else
552 		rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) &
553 					     ~(RTC_CTRL_B_AIE)));
554 
555 	/* Read Control C to clear all the flag bits. */
556 	rtc->read(rtc, RTC_CTRL_C);
557 	spin_unlock_irqrestore(&rtc->lock, flags);
558 
559 	return 0;
560 }
561 /* ----------------------------------------------------------------------- */
562 
563 
564 /* ----------------------------------------------------------------------- */
565 /* IRQ handler & workqueue. */
566 
567 /**
568  * ds1685_rtc_irq_handler - IRQ handler.
569  * @irq: IRQ number.
570  * @dev_id: platform device pointer.
571  */
572 static irqreturn_t
573 ds1685_rtc_irq_handler(int irq, void *dev_id)
574 {
575 	struct platform_device *pdev = dev_id;
576 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
577 	u8 ctrlb, ctrlc;
578 	unsigned long events = 0;
579 	u8 num_irqs = 0;
580 
581 	/* Abort early if the device isn't ready yet (i.e., DEBUG_SHIRQ). */
582 	if (unlikely(!rtc))
583 		return IRQ_HANDLED;
584 
585 	/* Ctrlb holds the interrupt-enable bits and ctrlc the flag bits. */
586 	spin_lock(&rtc->lock);
587 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
588 	ctrlc = rtc->read(rtc, RTC_CTRL_C);
589 
590 	/* Is the IRQF bit set? */
591 	if (likely(ctrlc & RTC_CTRL_C_IRQF)) {
592 		/*
593 		 * We need to determine if it was one of the standard
594 		 * events: PF, AF, or UF.  If so, we handle them and
595 		 * update the RTC core.
596 		 */
597 		if (likely(ctrlc & RTC_CTRL_B_PAU_MASK)) {
598 			events = RTC_IRQF;
599 
600 			/* Check for a periodic interrupt. */
601 			if ((ctrlb & RTC_CTRL_B_PIE) &&
602 			    (ctrlc & RTC_CTRL_C_PF)) {
603 				events |= RTC_PF;
604 				num_irqs++;
605 			}
606 
607 			/* Check for an alarm interrupt. */
608 			if ((ctrlb & RTC_CTRL_B_AIE) &&
609 			    (ctrlc & RTC_CTRL_C_AF)) {
610 				events |= RTC_AF;
611 				num_irqs++;
612 			}
613 
614 			/* Check for an update interrupt. */
615 			if ((ctrlb & RTC_CTRL_B_UIE) &&
616 			    (ctrlc & RTC_CTRL_C_UF)) {
617 				events |= RTC_UF;
618 				num_irqs++;
619 			}
620 
621 			rtc_update_irq(rtc->dev, num_irqs, events);
622 		} else {
623 			/*
624 			 * One of the "extended" interrupts was received that
625 			 * is not recognized by the RTC core.  These need to
626 			 * be handled in task context as they can call other
627 			 * functions and the time spent in irq context needs
628 			 * to be minimized.  Schedule them into a workqueue
629 			 * and inform the RTC core that the IRQs were handled.
630 			 */
631 			spin_unlock(&rtc->lock);
632 			schedule_work(&rtc->work);
633 			rtc_update_irq(rtc->dev, 0, 0);
634 			return IRQ_HANDLED;
635 		}
636 	}
637 	spin_unlock(&rtc->lock);
638 
639 	return events ? IRQ_HANDLED : IRQ_NONE;
640 }
641 
642 /**
643  * ds1685_rtc_work_queue - work queue handler.
644  * @work: work_struct containing data to work on in task context.
645  */
646 static void
647 ds1685_rtc_work_queue(struct work_struct *work)
648 {
649 	struct ds1685_priv *rtc = container_of(work,
650 					       struct ds1685_priv, work);
651 	struct platform_device *pdev = to_platform_device(&rtc->dev->dev);
652 	struct mutex *rtc_mutex = &rtc->dev->ops_lock;
653 	u8 ctrl4a, ctrl4b;
654 
655 	mutex_lock(rtc_mutex);
656 
657 	ds1685_rtc_switch_to_bank1(rtc);
658 	ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
659 	ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
660 
661 	/*
662 	 * Check for a kickstart interrupt. With Vcc applied, this
663 	 * typically means that the power button was pressed, so we
664 	 * begin the shutdown sequence.
665 	 */
666 	if ((ctrl4b & RTC_CTRL_4B_KSE) && (ctrl4a & RTC_CTRL_4A_KF)) {
667 		/* Briefly disable kickstarts to debounce button presses. */
668 		rtc->write(rtc, RTC_EXT_CTRL_4B,
669 			   (rtc->read(rtc, RTC_EXT_CTRL_4B) &
670 			    ~(RTC_CTRL_4B_KSE)));
671 
672 		/* Clear the kickstart flag. */
673 		rtc->write(rtc, RTC_EXT_CTRL_4A,
674 			   (ctrl4a & ~(RTC_CTRL_4A_KF)));
675 
676 
677 		/*
678 		 * Sleep 500ms before re-enabling kickstarts.  This allows
679 		 * adequate time to avoid reading signal jitter as additional
680 		 * button presses.
681 		 */
682 		msleep(500);
683 		rtc->write(rtc, RTC_EXT_CTRL_4B,
684 			   (rtc->read(rtc, RTC_EXT_CTRL_4B) |
685 			    RTC_CTRL_4B_KSE));
686 
687 		/* Call the platform pre-poweroff function. Else, shutdown. */
688 		if (rtc->prepare_poweroff != NULL)
689 			rtc->prepare_poweroff();
690 		else
691 			ds1685_rtc_poweroff(pdev);
692 	}
693 
694 	/*
695 	 * Check for a wake-up interrupt.  With Vcc applied, this is
696 	 * essentially a second alarm interrupt, except it takes into
697 	 * account the 'date' register in bank1 in addition to the
698 	 * standard three alarm registers.
699 	 */
700 	if ((ctrl4b & RTC_CTRL_4B_WIE) && (ctrl4a & RTC_CTRL_4A_WF)) {
701 		rtc->write(rtc, RTC_EXT_CTRL_4A,
702 			   (ctrl4a & ~(RTC_CTRL_4A_WF)));
703 
704 		/* Call the platform wake_alarm function if defined. */
705 		if (rtc->wake_alarm != NULL)
706 			rtc->wake_alarm();
707 		else
708 			dev_warn(&pdev->dev,
709 				 "Wake Alarm IRQ just occurred!\n");
710 	}
711 
712 	/*
713 	 * Check for a ram-clear interrupt.  This happens if RIE=1 and RF=0
714 	 * when RCE=1 in 4B.  This clears all NVRAM bytes in bank0 by setting
715 	 * each byte to a logic 1.  This has no effect on any extended
716 	 * NV-SRAM that might be present, nor on the time/calendar/alarm
717 	 * registers.  After a ram-clear is completed, there is a minimum
718 	 * recovery time of ~150ms in which all reads/writes are locked out.
719 	 * NOTE: A ram-clear can still occur if RCE=1 and RIE=0.  We cannot
720 	 * catch this scenario.
721 	 */
722 	if ((ctrl4b & RTC_CTRL_4B_RIE) && (ctrl4a & RTC_CTRL_4A_RF)) {
723 		rtc->write(rtc, RTC_EXT_CTRL_4A,
724 			   (ctrl4a & ~(RTC_CTRL_4A_RF)));
725 		msleep(150);
726 
727 		/* Call the platform post_ram_clear function if defined. */
728 		if (rtc->post_ram_clear != NULL)
729 			rtc->post_ram_clear();
730 		else
731 			dev_warn(&pdev->dev,
732 				 "RAM-Clear IRQ just occurred!\n");
733 	}
734 	ds1685_rtc_switch_to_bank0(rtc);
735 
736 	mutex_unlock(rtc_mutex);
737 }
738 /* ----------------------------------------------------------------------- */
739 
740 
741 /* ----------------------------------------------------------------------- */
742 /* ProcFS interface */
743 
744 #ifdef CONFIG_PROC_FS
745 #define NUM_REGS	6	/* Num of control registers. */
746 #define NUM_BITS	8	/* Num bits per register. */
747 #define NUM_SPACES	4	/* Num spaces between each bit. */
748 
749 /*
750  * Periodic Interrupt Rates.
751  */
752 static const char *ds1685_rtc_pirq_rate[16] = {
753 	"none", "3.90625ms", "7.8125ms", "0.122070ms", "0.244141ms",
754 	"0.488281ms", "0.9765625ms", "1.953125ms", "3.90625ms", "7.8125ms",
755 	"15.625ms", "31.25ms", "62.5ms", "125ms", "250ms", "500ms"
756 };
757 
758 /*
759  * Square-Wave Output Frequencies.
760  */
761 static const char *ds1685_rtc_sqw_freq[16] = {
762 	"none", "256Hz", "128Hz", "8192Hz", "4096Hz", "2048Hz", "1024Hz",
763 	"512Hz", "256Hz", "128Hz", "64Hz", "32Hz", "16Hz", "8Hz", "4Hz", "2Hz"
764 };
765 
766 #ifdef CONFIG_RTC_DS1685_PROC_REGS
767 /**
768  * ds1685_rtc_print_regs - helper function to print register values.
769  * @hex: hex byte to convert into binary bits.
770  * @dest: destination char array.
771  *
772  * This is basically a hex->binary function, just with extra spacing between
773  * the digits.  It only works on 1-byte values (8 bits).
774  */
775 static char*
776 ds1685_rtc_print_regs(u8 hex, char *dest)
777 {
778 	u32 i, j;
779 	char *tmp = dest;
780 
781 	for (i = 0; i < NUM_BITS; i++) {
782 		*tmp++ = ((hex & 0x80) != 0 ? '1' : '0');
783 		for (j = 0; j < NUM_SPACES; j++)
784 			*tmp++ = ' ';
785 		hex <<= 1;
786 	}
787 	*tmp++ = '\0';
788 
789 	return dest;
790 }
791 #endif
792 
793 /**
794  * ds1685_rtc_proc - procfs access function.
795  * @dev: pointer to device structure.
796  * @seq: pointer to seq_file structure.
797  */
798 static int
799 ds1685_rtc_proc(struct device *dev, struct seq_file *seq)
800 {
801 	struct platform_device *pdev = to_platform_device(dev);
802 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
803 	u8 ctrla, ctrlb, ctrlc, ctrld, ctrl4a, ctrl4b, ssn[8];
804 	char *model;
805 #ifdef CONFIG_RTC_DS1685_PROC_REGS
806 	char bits[NUM_REGS][(NUM_BITS * NUM_SPACES) + NUM_BITS + 1];
807 #endif
808 
809 	/* Read all the relevant data from the control registers. */
810 	ds1685_rtc_switch_to_bank1(rtc);
811 	ds1685_rtc_get_ssn(rtc, ssn);
812 	ctrla = rtc->read(rtc, RTC_CTRL_A);
813 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
814 	ctrlc = rtc->read(rtc, RTC_CTRL_C);
815 	ctrld = rtc->read(rtc, RTC_CTRL_D);
816 	ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
817 	ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
818 	ds1685_rtc_switch_to_bank0(rtc);
819 
820 	/* Determine the RTC model. */
821 	switch (ssn[0]) {
822 	case RTC_MODEL_DS1685:
823 		model = "DS1685/DS1687\0";
824 		break;
825 	case RTC_MODEL_DS1689:
826 		model = "DS1689/DS1693\0";
827 		break;
828 	case RTC_MODEL_DS17285:
829 		model = "DS17285/DS17287\0";
830 		break;
831 	case RTC_MODEL_DS17485:
832 		model = "DS17485/DS17487\0";
833 		break;
834 	case RTC_MODEL_DS17885:
835 		model = "DS17885/DS17887\0";
836 		break;
837 	default:
838 		model = "Unknown\0";
839 		break;
840 	}
841 
842 	/* Print out the information. */
843 	seq_printf(seq,
844 	   "Model\t\t: %s\n"
845 	   "Oscillator\t: %s\n"
846 	   "12/24hr\t\t: %s\n"
847 	   "DST\t\t: %s\n"
848 	   "Data mode\t: %s\n"
849 	   "Battery\t\t: %s\n"
850 	   "Aux batt\t: %s\n"
851 	   "Update IRQ\t: %s\n"
852 	   "Periodic IRQ\t: %s\n"
853 	   "Periodic Rate\t: %s\n"
854 	   "SQW Freq\t: %s\n"
855 #ifdef CONFIG_RTC_DS1685_PROC_REGS
856 	   "Serial #\t: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n"
857 	   "Register Status\t:\n"
858 	   "   Ctrl A\t: UIP  DV2  DV1  DV0  RS3  RS2  RS1  RS0\n"
859 	   "\t\t:  %s\n"
860 	   "   Ctrl B\t: SET  PIE  AIE  UIE  SQWE  DM  2412 DSE\n"
861 	   "\t\t:  %s\n"
862 	   "   Ctrl C\t: IRQF  PF   AF   UF  ---  ---  ---  ---\n"
863 	   "\t\t:  %s\n"
864 	   "   Ctrl D\t: VRT  ---  ---  ---  ---  ---  ---  ---\n"
865 	   "\t\t:  %s\n"
866 #if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
867 	   "   Ctrl 4A\t: VRT2 INCR BME  ---  PAB   RF   WF   KF\n"
868 #else
869 	   "   Ctrl 4A\t: VRT2 INCR ---  ---  PAB   RF   WF   KF\n"
870 #endif
871 	   "\t\t:  %s\n"
872 	   "   Ctrl 4B\t: ABE  E32k  CS  RCE  PRS  RIE  WIE  KSE\n"
873 	   "\t\t:  %s\n",
874 #else
875 	   "Serial #\t: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
876 #endif
877 	   model,
878 	   ((ctrla & RTC_CTRL_A_DV1) ? "enabled" : "disabled"),
879 	   ((ctrlb & RTC_CTRL_B_2412) ? "24-hour" : "12-hour"),
880 	   ((ctrlb & RTC_CTRL_B_DSE) ? "enabled" : "disabled"),
881 	   ((ctrlb & RTC_CTRL_B_DM) ? "binary" : "BCD"),
882 	   ((ctrld & RTC_CTRL_D_VRT) ? "ok" : "exhausted or n/a"),
883 	   ((ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "exhausted or n/a"),
884 	   ((ctrlb & RTC_CTRL_B_UIE) ? "yes" : "no"),
885 	   ((ctrlb & RTC_CTRL_B_PIE) ? "yes" : "no"),
886 	   (!(ctrl4b & RTC_CTRL_4B_E32K) ?
887 	    ds1685_rtc_pirq_rate[(ctrla & RTC_CTRL_A_RS_MASK)] : "none"),
888 	   (!((ctrl4b & RTC_CTRL_4B_E32K)) ?
889 	    ds1685_rtc_sqw_freq[(ctrla & RTC_CTRL_A_RS_MASK)] : "32768Hz"),
890 #ifdef CONFIG_RTC_DS1685_PROC_REGS
891 	   ssn[0], ssn[1], ssn[2], ssn[3], ssn[4], ssn[5], ssn[6], ssn[7],
892 	   ds1685_rtc_print_regs(ctrla, bits[0]),
893 	   ds1685_rtc_print_regs(ctrlb, bits[1]),
894 	   ds1685_rtc_print_regs(ctrlc, bits[2]),
895 	   ds1685_rtc_print_regs(ctrld, bits[3]),
896 	   ds1685_rtc_print_regs(ctrl4a, bits[4]),
897 	   ds1685_rtc_print_regs(ctrl4b, bits[5]));
898 #else
899 	   ssn[0], ssn[1], ssn[2], ssn[3], ssn[4], ssn[5], ssn[6], ssn[7]);
900 #endif
901 	return 0;
902 }
903 #else
904 #define ds1685_rtc_proc NULL
905 #endif /* CONFIG_PROC_FS */
906 /* ----------------------------------------------------------------------- */
907 
908 
909 /* ----------------------------------------------------------------------- */
910 /* RTC Class operations */
911 
912 static const struct rtc_class_ops
913 ds1685_rtc_ops = {
914 	.proc = ds1685_rtc_proc,
915 	.read_time = ds1685_rtc_read_time,
916 	.set_time = ds1685_rtc_set_time,
917 	.read_alarm = ds1685_rtc_read_alarm,
918 	.set_alarm = ds1685_rtc_set_alarm,
919 	.alarm_irq_enable = ds1685_rtc_alarm_irq_enable,
920 };
921 /* ----------------------------------------------------------------------- */
922 
923 
924 /* ----------------------------------------------------------------------- */
925 /* SysFS interface */
926 
927 #ifdef CONFIG_SYSFS
928 /**
929  * ds1685_rtc_sysfs_nvram_read - reads rtc nvram via sysfs.
930  * @file: pointer to file structure.
931  * @kobj: pointer to kobject structure.
932  * @bin_attr: pointer to bin_attribute structure.
933  * @buf: pointer to char array to hold the output.
934  * @pos: current file position pointer.
935  * @size: size of the data to read.
936  */
937 static ssize_t
938 ds1685_rtc_sysfs_nvram_read(struct file *filp, struct kobject *kobj,
939 			    struct bin_attribute *bin_attr, char *buf,
940 			    loff_t pos, size_t size)
941 {
942 	struct platform_device *pdev =
943 		to_platform_device(container_of(kobj, struct device, kobj));
944 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
945 	ssize_t count;
946 	unsigned long flags = 0;
947 
948 	spin_lock_irqsave(&rtc->lock, flags);
949 	ds1685_rtc_switch_to_bank0(rtc);
950 
951 	/* Read NVRAM in time and bank0 registers. */
952 	for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
953 	     count++, size--) {
954 		if (count < NVRAM_SZ_TIME)
955 			*buf++ = rtc->read(rtc, (NVRAM_TIME_BASE + pos++));
956 		else
957 			*buf++ = rtc->read(rtc, (NVRAM_BANK0_BASE + pos++));
958 	}
959 
960 #ifndef CONFIG_RTC_DRV_DS1689
961 	if (size > 0) {
962 		ds1685_rtc_switch_to_bank1(rtc);
963 
964 #ifndef CONFIG_RTC_DRV_DS1685
965 		/* Enable burst-mode on DS17x85/DS17x87 */
966 		rtc->write(rtc, RTC_EXT_CTRL_4A,
967 			   (rtc->read(rtc, RTC_EXT_CTRL_4A) |
968 			    RTC_CTRL_4A_BME));
969 
970 		/* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
971 		 * reading with burst-mode */
972 		rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
973 			   (pos - NVRAM_TOTAL_SZ_BANK0));
974 #endif
975 
976 		/* Read NVRAM in bank1 registers. */
977 		for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
978 		     count++, size--) {
979 #ifdef CONFIG_RTC_DRV_DS1685
980 			/* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
981 			 * before each read. */
982 			rtc->write(rtc, RTC_BANK1_RAM_ADDR,
983 				   (pos - NVRAM_TOTAL_SZ_BANK0));
984 #endif
985 			*buf++ = rtc->read(rtc, RTC_BANK1_RAM_DATA_PORT);
986 			pos++;
987 		}
988 
989 #ifndef CONFIG_RTC_DRV_DS1685
990 		/* Disable burst-mode on DS17x85/DS17x87 */
991 		rtc->write(rtc, RTC_EXT_CTRL_4A,
992 			   (rtc->read(rtc, RTC_EXT_CTRL_4A) &
993 			    ~(RTC_CTRL_4A_BME)));
994 #endif
995 		ds1685_rtc_switch_to_bank0(rtc);
996 	}
997 #endif /* !CONFIG_RTC_DRV_DS1689 */
998 	spin_unlock_irqrestore(&rtc->lock, flags);
999 
1000 	/*
1001 	 * XXX: Bug? this appears to cause the function to get executed
1002 	 * several times in succession.  But it's the only way to actually get
1003 	 * data written out to a file.
1004 	 */
1005 	return count;
1006 }
1007 
1008 /**
1009  * ds1685_rtc_sysfs_nvram_write - writes rtc nvram via sysfs.
1010  * @file: pointer to file structure.
1011  * @kobj: pointer to kobject structure.
1012  * @bin_attr: pointer to bin_attribute structure.
1013  * @buf: pointer to char array to hold the input.
1014  * @pos: current file position pointer.
1015  * @size: size of the data to write.
1016  */
1017 static ssize_t
1018 ds1685_rtc_sysfs_nvram_write(struct file *filp, struct kobject *kobj,
1019 			     struct bin_attribute *bin_attr, char *buf,
1020 			     loff_t pos, size_t size)
1021 {
1022 	struct platform_device *pdev =
1023 		to_platform_device(container_of(kobj, struct device, kobj));
1024 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1025 	ssize_t count;
1026 	unsigned long flags = 0;
1027 
1028 	spin_lock_irqsave(&rtc->lock, flags);
1029 	ds1685_rtc_switch_to_bank0(rtc);
1030 
1031 	/* Write NVRAM in time and bank0 registers. */
1032 	for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
1033 	     count++, size--)
1034 		if (count < NVRAM_SZ_TIME)
1035 			rtc->write(rtc, (NVRAM_TIME_BASE + pos++),
1036 				   *buf++);
1037 		else
1038 			rtc->write(rtc, (NVRAM_BANK0_BASE), *buf++);
1039 
1040 #ifndef CONFIG_RTC_DRV_DS1689
1041 	if (size > 0) {
1042 		ds1685_rtc_switch_to_bank1(rtc);
1043 
1044 #ifndef CONFIG_RTC_DRV_DS1685
1045 		/* Enable burst-mode on DS17x85/DS17x87 */
1046 		rtc->write(rtc, RTC_EXT_CTRL_4A,
1047 			   (rtc->read(rtc, RTC_EXT_CTRL_4A) |
1048 			    RTC_CTRL_4A_BME));
1049 
1050 		/* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
1051 		 * writing with burst-mode */
1052 		rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
1053 			   (pos - NVRAM_TOTAL_SZ_BANK0));
1054 #endif
1055 
1056 		/* Write NVRAM in bank1 registers. */
1057 		for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
1058 		     count++, size--) {
1059 #ifdef CONFIG_RTC_DRV_DS1685
1060 			/* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
1061 			 * before each read. */
1062 			rtc->write(rtc, RTC_BANK1_RAM_ADDR,
1063 				   (pos - NVRAM_TOTAL_SZ_BANK0));
1064 #endif
1065 			rtc->write(rtc, RTC_BANK1_RAM_DATA_PORT, *buf++);
1066 			pos++;
1067 		}
1068 
1069 #ifndef CONFIG_RTC_DRV_DS1685
1070 		/* Disable burst-mode on DS17x85/DS17x87 */
1071 		rtc->write(rtc, RTC_EXT_CTRL_4A,
1072 			   (rtc->read(rtc, RTC_EXT_CTRL_4A) &
1073 			    ~(RTC_CTRL_4A_BME)));
1074 #endif
1075 		ds1685_rtc_switch_to_bank0(rtc);
1076 	}
1077 #endif /* !CONFIG_RTC_DRV_DS1689 */
1078 	spin_unlock_irqrestore(&rtc->lock, flags);
1079 
1080 	return count;
1081 }
1082 
1083 /**
1084  * struct ds1685_rtc_sysfs_nvram_attr - sysfs attributes for rtc nvram.
1085  * @attr: nvram attributes.
1086  * @read: nvram read function.
1087  * @write: nvram write function.
1088  * @size: nvram total size (bank0 + extended).
1089  */
1090 static struct bin_attribute
1091 ds1685_rtc_sysfs_nvram_attr = {
1092 	.attr = {
1093 		.name = "nvram",
1094 		.mode = S_IRUGO | S_IWUSR,
1095 	},
1096 	.read = ds1685_rtc_sysfs_nvram_read,
1097 	.write = ds1685_rtc_sysfs_nvram_write,
1098 	.size = NVRAM_TOTAL_SZ
1099 };
1100 
1101 /**
1102  * ds1685_rtc_sysfs_battery_show - sysfs file for main battery status.
1103  * @dev: pointer to device structure.
1104  * @attr: pointer to device_attribute structure.
1105  * @buf: pointer to char array to hold the output.
1106  */
1107 static ssize_t
1108 ds1685_rtc_sysfs_battery_show(struct device *dev,
1109 			      struct device_attribute *attr, char *buf)
1110 {
1111 	struct platform_device *pdev = to_platform_device(dev);
1112 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1113 	u8 ctrld;
1114 
1115 	ctrld = rtc->read(rtc, RTC_CTRL_D);
1116 
1117 	return snprintf(buf, 13, "%s\n",
1118 			(ctrld & RTC_CTRL_D_VRT) ? "ok" : "not ok or N/A");
1119 }
1120 static DEVICE_ATTR(battery, S_IRUGO, ds1685_rtc_sysfs_battery_show, NULL);
1121 
1122 /**
1123  * ds1685_rtc_sysfs_auxbatt_show - sysfs file for aux battery status.
1124  * @dev: pointer to device structure.
1125  * @attr: pointer to device_attribute structure.
1126  * @buf: pointer to char array to hold the output.
1127  */
1128 static ssize_t
1129 ds1685_rtc_sysfs_auxbatt_show(struct device *dev,
1130 			      struct device_attribute *attr, char *buf)
1131 {
1132 	struct platform_device *pdev = to_platform_device(dev);
1133 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1134 	u8 ctrl4a;
1135 
1136 	ds1685_rtc_switch_to_bank1(rtc);
1137 	ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
1138 	ds1685_rtc_switch_to_bank0(rtc);
1139 
1140 	return snprintf(buf, 13, "%s\n",
1141 			(ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "not ok or N/A");
1142 }
1143 static DEVICE_ATTR(auxbatt, S_IRUGO, ds1685_rtc_sysfs_auxbatt_show, NULL);
1144 
1145 /**
1146  * ds1685_rtc_sysfs_serial_show - sysfs file for silicon serial number.
1147  * @dev: pointer to device structure.
1148  * @attr: pointer to device_attribute structure.
1149  * @buf: pointer to char array to hold the output.
1150  */
1151 static ssize_t
1152 ds1685_rtc_sysfs_serial_show(struct device *dev,
1153 			     struct device_attribute *attr, char *buf)
1154 {
1155 	struct platform_device *pdev = to_platform_device(dev);
1156 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1157 	u8 ssn[8];
1158 
1159 	ds1685_rtc_switch_to_bank1(rtc);
1160 	ds1685_rtc_get_ssn(rtc, ssn);
1161 	ds1685_rtc_switch_to_bank0(rtc);
1162 
1163 	return snprintf(buf, 24, "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
1164 			ssn[0], ssn[1], ssn[2], ssn[3], ssn[4], ssn[5],
1165 			ssn[6], ssn[7]);
1166 
1167 	return 0;
1168 }
1169 static DEVICE_ATTR(serial, S_IRUGO, ds1685_rtc_sysfs_serial_show, NULL);
1170 
1171 /**
1172  * struct ds1685_rtc_sysfs_misc_attrs - list for misc RTC features.
1173  */
1174 static struct attribute*
1175 ds1685_rtc_sysfs_misc_attrs[] = {
1176 	&dev_attr_battery.attr,
1177 	&dev_attr_auxbatt.attr,
1178 	&dev_attr_serial.attr,
1179 	NULL,
1180 };
1181 
1182 /**
1183  * struct ds1685_rtc_sysfs_misc_grp - attr group for misc RTC features.
1184  */
1185 static const struct attribute_group
1186 ds1685_rtc_sysfs_misc_grp = {
1187 	.name = "misc",
1188 	.attrs = ds1685_rtc_sysfs_misc_attrs,
1189 };
1190 
1191 #ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1192 /**
1193  * struct ds1685_rtc_ctrl_regs.
1194  * @name: char pointer for the bit name.
1195  * @reg: control register the bit is in.
1196  * @bit: the bit's offset in the register.
1197  */
1198 struct ds1685_rtc_ctrl_regs {
1199 	const char *name;
1200 	const u8 reg;
1201 	const u8 bit;
1202 };
1203 
1204 /*
1205  * Ctrl register bit lookup table.
1206  */
1207 static const struct ds1685_rtc_ctrl_regs
1208 ds1685_ctrl_regs_table[] = {
1209 	{ "uip",  RTC_CTRL_A,      RTC_CTRL_A_UIP   },
1210 	{ "dv2",  RTC_CTRL_A,      RTC_CTRL_A_DV2   },
1211 	{ "dv1",  RTC_CTRL_A,      RTC_CTRL_A_DV1   },
1212 	{ "dv0",  RTC_CTRL_A,      RTC_CTRL_A_DV0   },
1213 	{ "rs3",  RTC_CTRL_A,      RTC_CTRL_A_RS3   },
1214 	{ "rs2",  RTC_CTRL_A,      RTC_CTRL_A_RS2   },
1215 	{ "rs1",  RTC_CTRL_A,      RTC_CTRL_A_RS1   },
1216 	{ "rs0",  RTC_CTRL_A,      RTC_CTRL_A_RS0   },
1217 	{ "set",  RTC_CTRL_B,      RTC_CTRL_B_SET   },
1218 	{ "pie",  RTC_CTRL_B,      RTC_CTRL_B_PIE   },
1219 	{ "aie",  RTC_CTRL_B,      RTC_CTRL_B_AIE   },
1220 	{ "uie",  RTC_CTRL_B,      RTC_CTRL_B_UIE   },
1221 	{ "sqwe", RTC_CTRL_B,      RTC_CTRL_B_SQWE  },
1222 	{ "dm",   RTC_CTRL_B,      RTC_CTRL_B_DM    },
1223 	{ "2412", RTC_CTRL_B,      RTC_CTRL_B_2412  },
1224 	{ "dse",  RTC_CTRL_B,      RTC_CTRL_B_DSE   },
1225 	{ "irqf", RTC_CTRL_C,      RTC_CTRL_C_IRQF  },
1226 	{ "pf",   RTC_CTRL_C,      RTC_CTRL_C_PF    },
1227 	{ "af",   RTC_CTRL_C,      RTC_CTRL_C_AF    },
1228 	{ "uf",   RTC_CTRL_C,      RTC_CTRL_C_UF    },
1229 	{ "vrt",  RTC_CTRL_D,      RTC_CTRL_D_VRT   },
1230 	{ "vrt2", RTC_EXT_CTRL_4A, RTC_CTRL_4A_VRT2 },
1231 	{ "incr", RTC_EXT_CTRL_4A, RTC_CTRL_4A_INCR },
1232 	{ "pab",  RTC_EXT_CTRL_4A, RTC_CTRL_4A_PAB  },
1233 	{ "rf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_RF   },
1234 	{ "wf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_WF   },
1235 	{ "kf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_KF   },
1236 #if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1237 	{ "bme",  RTC_EXT_CTRL_4A, RTC_CTRL_4A_BME  },
1238 #endif
1239 	{ "abe",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_ABE  },
1240 	{ "e32k", RTC_EXT_CTRL_4B, RTC_CTRL_4B_E32K },
1241 	{ "cs",   RTC_EXT_CTRL_4B, RTC_CTRL_4B_CS   },
1242 	{ "rce",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_RCE  },
1243 	{ "prs",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_PRS  },
1244 	{ "rie",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_RIE  },
1245 	{ "wie",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_WIE  },
1246 	{ "kse",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_KSE  },
1247 	{ NULL,   0,               0                },
1248 };
1249 
1250 /**
1251  * ds1685_rtc_sysfs_ctrl_regs_lookup - ctrl register bit lookup function.
1252  * @name: ctrl register bit to look up in ds1685_ctrl_regs_table.
1253  */
1254 static const struct ds1685_rtc_ctrl_regs*
1255 ds1685_rtc_sysfs_ctrl_regs_lookup(const char *name)
1256 {
1257 	const struct ds1685_rtc_ctrl_regs *p = ds1685_ctrl_regs_table;
1258 
1259 	for (; p->name != NULL; ++p)
1260 		if (strcmp(p->name, name) == 0)
1261 			return p;
1262 
1263 	return NULL;
1264 }
1265 
1266 /**
1267  * ds1685_rtc_sysfs_ctrl_regs_show - reads a ctrl register bit via sysfs.
1268  * @dev: pointer to device structure.
1269  * @attr: pointer to device_attribute structure.
1270  * @buf: pointer to char array to hold the output.
1271  */
1272 static ssize_t
1273 ds1685_rtc_sysfs_ctrl_regs_show(struct device *dev,
1274 				struct device_attribute *attr, char *buf)
1275 {
1276 	u8 tmp;
1277 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1278 	const struct ds1685_rtc_ctrl_regs *reg_info =
1279 		ds1685_rtc_sysfs_ctrl_regs_lookup(attr->attr.name);
1280 
1281 	/* Make sure we actually matched something. */
1282 	if (!reg_info)
1283 		return -EINVAL;
1284 
1285 	/* No spinlock during a read -- mutex is already held. */
1286 	ds1685_rtc_switch_to_bank1(rtc);
1287 	tmp = rtc->read(rtc, reg_info->reg) & reg_info->bit;
1288 	ds1685_rtc_switch_to_bank0(rtc);
1289 
1290 	return snprintf(buf, 2, "%d\n", (tmp ? 1 : 0));
1291 }
1292 
1293 /**
1294  * ds1685_rtc_sysfs_ctrl_regs_store - writes a ctrl register bit via sysfs.
1295  * @dev: pointer to device structure.
1296  * @attr: pointer to device_attribute structure.
1297  * @buf: pointer to char array to hold the output.
1298  * @count: number of bytes written.
1299  */
1300 static ssize_t
1301 ds1685_rtc_sysfs_ctrl_regs_store(struct device *dev,
1302 				 struct device_attribute *attr,
1303 				 const char *buf, size_t count)
1304 {
1305 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1306 	u8 reg = 0, bit = 0, tmp;
1307 	unsigned long flags = 0;
1308 	long int val = 0;
1309 	const struct ds1685_rtc_ctrl_regs *reg_info =
1310 		ds1685_rtc_sysfs_ctrl_regs_lookup(attr->attr.name);
1311 
1312 	/* We only accept numbers. */
1313 	if (kstrtol(buf, 10, &val) < 0)
1314 		return -EINVAL;
1315 
1316 	/* bits are binary, 0 or 1 only. */
1317 	if ((val != 0) && (val != 1))
1318 		return -ERANGE;
1319 
1320 	/* Make sure we actually matched something. */
1321 	if (!reg_info)
1322 		return -EINVAL;
1323 
1324 	reg = reg_info->reg;
1325 	bit = reg_info->bit;
1326 
1327 	/* Safe to spinlock during a write. */
1328 	ds1685_rtc_begin_ctrl_access(rtc, flags);
1329 	tmp = rtc->read(rtc, reg);
1330 	rtc->write(rtc, reg, (val ? (tmp | bit) : (tmp & ~(bit))));
1331 	ds1685_rtc_end_ctrl_access(rtc, flags);
1332 
1333 	return count;
1334 }
1335 
1336 /**
1337  * DS1685_RTC_SYSFS_CTRL_REG_RO - device_attribute for read-only register bit.
1338  * @bit: bit to read.
1339  */
1340 #define DS1685_RTC_SYSFS_CTRL_REG_RO(bit)				\
1341 	static DEVICE_ATTR(bit, S_IRUGO,				\
1342 	ds1685_rtc_sysfs_ctrl_regs_show, NULL)
1343 
1344 /**
1345  * DS1685_RTC_SYSFS_CTRL_REG_RW - device_attribute for read-write register bit.
1346  * @bit: bit to read or write.
1347  */
1348 #define DS1685_RTC_SYSFS_CTRL_REG_RW(bit)				\
1349 	static DEVICE_ATTR(bit, S_IRUGO | S_IWUSR,			\
1350 	ds1685_rtc_sysfs_ctrl_regs_show,				\
1351 	ds1685_rtc_sysfs_ctrl_regs_store)
1352 
1353 /*
1354  * Control Register A bits.
1355  */
1356 DS1685_RTC_SYSFS_CTRL_REG_RO(uip);
1357 DS1685_RTC_SYSFS_CTRL_REG_RW(dv2);
1358 DS1685_RTC_SYSFS_CTRL_REG_RW(dv1);
1359 DS1685_RTC_SYSFS_CTRL_REG_RO(dv0);
1360 DS1685_RTC_SYSFS_CTRL_REG_RW(rs3);
1361 DS1685_RTC_SYSFS_CTRL_REG_RW(rs2);
1362 DS1685_RTC_SYSFS_CTRL_REG_RW(rs1);
1363 DS1685_RTC_SYSFS_CTRL_REG_RW(rs0);
1364 
1365 static struct attribute*
1366 ds1685_rtc_sysfs_ctrla_attrs[] = {
1367 	&dev_attr_uip.attr,
1368 	&dev_attr_dv2.attr,
1369 	&dev_attr_dv1.attr,
1370 	&dev_attr_dv0.attr,
1371 	&dev_attr_rs3.attr,
1372 	&dev_attr_rs2.attr,
1373 	&dev_attr_rs1.attr,
1374 	&dev_attr_rs0.attr,
1375 	NULL,
1376 };
1377 
1378 static const struct attribute_group
1379 ds1685_rtc_sysfs_ctrla_grp = {
1380 	.name = "ctrla",
1381 	.attrs = ds1685_rtc_sysfs_ctrla_attrs,
1382 };
1383 
1384 
1385 /*
1386  * Control Register B bits.
1387  */
1388 DS1685_RTC_SYSFS_CTRL_REG_RO(set);
1389 DS1685_RTC_SYSFS_CTRL_REG_RW(pie);
1390 DS1685_RTC_SYSFS_CTRL_REG_RW(aie);
1391 DS1685_RTC_SYSFS_CTRL_REG_RW(uie);
1392 DS1685_RTC_SYSFS_CTRL_REG_RW(sqwe);
1393 DS1685_RTC_SYSFS_CTRL_REG_RO(dm);
1394 DS1685_RTC_SYSFS_CTRL_REG_RO(2412);
1395 DS1685_RTC_SYSFS_CTRL_REG_RO(dse);
1396 
1397 static struct attribute*
1398 ds1685_rtc_sysfs_ctrlb_attrs[] = {
1399 	&dev_attr_set.attr,
1400 	&dev_attr_pie.attr,
1401 	&dev_attr_aie.attr,
1402 	&dev_attr_uie.attr,
1403 	&dev_attr_sqwe.attr,
1404 	&dev_attr_dm.attr,
1405 	&dev_attr_2412.attr,
1406 	&dev_attr_dse.attr,
1407 	NULL,
1408 };
1409 
1410 static const struct attribute_group
1411 ds1685_rtc_sysfs_ctrlb_grp = {
1412 	.name = "ctrlb",
1413 	.attrs = ds1685_rtc_sysfs_ctrlb_attrs,
1414 };
1415 
1416 /*
1417  * Control Register C bits.
1418  *
1419  * Reading Control C clears these bits!  Reading them individually can
1420  * possibly cause an interrupt to be missed.  Use the /proc interface
1421  * to see all the bits in this register simultaneously.
1422  */
1423 DS1685_RTC_SYSFS_CTRL_REG_RO(irqf);
1424 DS1685_RTC_SYSFS_CTRL_REG_RO(pf);
1425 DS1685_RTC_SYSFS_CTRL_REG_RO(af);
1426 DS1685_RTC_SYSFS_CTRL_REG_RO(uf);
1427 
1428 static struct attribute*
1429 ds1685_rtc_sysfs_ctrlc_attrs[] = {
1430 	&dev_attr_irqf.attr,
1431 	&dev_attr_pf.attr,
1432 	&dev_attr_af.attr,
1433 	&dev_attr_uf.attr,
1434 	NULL,
1435 };
1436 
1437 static const struct attribute_group
1438 ds1685_rtc_sysfs_ctrlc_grp = {
1439 	.name = "ctrlc",
1440 	.attrs = ds1685_rtc_sysfs_ctrlc_attrs,
1441 };
1442 
1443 /*
1444  * Control Register D bits.
1445  */
1446 DS1685_RTC_SYSFS_CTRL_REG_RO(vrt);
1447 
1448 static struct attribute*
1449 ds1685_rtc_sysfs_ctrld_attrs[] = {
1450 	&dev_attr_vrt.attr,
1451 	NULL,
1452 };
1453 
1454 static const struct attribute_group
1455 ds1685_rtc_sysfs_ctrld_grp = {
1456 	.name = "ctrld",
1457 	.attrs = ds1685_rtc_sysfs_ctrld_attrs,
1458 };
1459 
1460 /*
1461  * Control Register 4A bits.
1462  */
1463 DS1685_RTC_SYSFS_CTRL_REG_RO(vrt2);
1464 DS1685_RTC_SYSFS_CTRL_REG_RO(incr);
1465 DS1685_RTC_SYSFS_CTRL_REG_RW(pab);
1466 DS1685_RTC_SYSFS_CTRL_REG_RW(rf);
1467 DS1685_RTC_SYSFS_CTRL_REG_RW(wf);
1468 DS1685_RTC_SYSFS_CTRL_REG_RW(kf);
1469 #if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1470 DS1685_RTC_SYSFS_CTRL_REG_RO(bme);
1471 #endif
1472 
1473 static struct attribute*
1474 ds1685_rtc_sysfs_ctrl4a_attrs[] = {
1475 	&dev_attr_vrt2.attr,
1476 	&dev_attr_incr.attr,
1477 	&dev_attr_pab.attr,
1478 	&dev_attr_rf.attr,
1479 	&dev_attr_wf.attr,
1480 	&dev_attr_kf.attr,
1481 #if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1482 	&dev_attr_bme.attr,
1483 #endif
1484 	NULL,
1485 };
1486 
1487 static const struct attribute_group
1488 ds1685_rtc_sysfs_ctrl4a_grp = {
1489 	.name = "ctrl4a",
1490 	.attrs = ds1685_rtc_sysfs_ctrl4a_attrs,
1491 };
1492 
1493 /*
1494  * Control Register 4B bits.
1495  */
1496 DS1685_RTC_SYSFS_CTRL_REG_RW(abe);
1497 DS1685_RTC_SYSFS_CTRL_REG_RW(e32k);
1498 DS1685_RTC_SYSFS_CTRL_REG_RO(cs);
1499 DS1685_RTC_SYSFS_CTRL_REG_RW(rce);
1500 DS1685_RTC_SYSFS_CTRL_REG_RW(prs);
1501 DS1685_RTC_SYSFS_CTRL_REG_RW(rie);
1502 DS1685_RTC_SYSFS_CTRL_REG_RW(wie);
1503 DS1685_RTC_SYSFS_CTRL_REG_RW(kse);
1504 
1505 static struct attribute*
1506 ds1685_rtc_sysfs_ctrl4b_attrs[] = {
1507 	&dev_attr_abe.attr,
1508 	&dev_attr_e32k.attr,
1509 	&dev_attr_cs.attr,
1510 	&dev_attr_rce.attr,
1511 	&dev_attr_prs.attr,
1512 	&dev_attr_rie.attr,
1513 	&dev_attr_wie.attr,
1514 	&dev_attr_kse.attr,
1515 	NULL,
1516 };
1517 
1518 static const struct attribute_group
1519 ds1685_rtc_sysfs_ctrl4b_grp = {
1520 	.name = "ctrl4b",
1521 	.attrs = ds1685_rtc_sysfs_ctrl4b_attrs,
1522 };
1523 
1524 
1525 /**
1526  * struct ds1685_rtc_ctrl_regs.
1527  * @name: char pointer for the bit name.
1528  * @reg: control register the bit is in.
1529  * @bit: the bit's offset in the register.
1530  */
1531 struct ds1685_rtc_time_regs {
1532 	const char *name;
1533 	const u8 reg;
1534 	const u8 mask;
1535 	const u8 min;
1536 	const u8 max;
1537 };
1538 
1539 /*
1540  * Time/Date register lookup tables.
1541  */
1542 static const struct ds1685_rtc_time_regs
1543 ds1685_time_regs_bcd_table[] = {
1544 	{ "seconds",       RTC_SECS,       RTC_SECS_BCD_MASK,   0, 59 },
1545 	{ "minutes",       RTC_MINS,       RTC_MINS_BCD_MASK,   0, 59 },
1546 	{ "hours",         RTC_HRS,        RTC_HRS_24_BCD_MASK, 0, 23 },
1547 	{ "wday",          RTC_WDAY,       RTC_WDAY_MASK,       1,  7 },
1548 	{ "mday",          RTC_MDAY,       RTC_MDAY_BCD_MASK,   1, 31 },
1549 	{ "month",         RTC_MONTH,      RTC_MONTH_BCD_MASK,  1, 12 },
1550 	{ "year",          RTC_YEAR,       RTC_YEAR_BCD_MASK,   0, 99 },
1551 	{ "century",       RTC_CENTURY,    RTC_CENTURY_MASK,    0, 99 },
1552 	{ "alarm_seconds", RTC_SECS_ALARM, RTC_SECS_BCD_MASK,   0, 59 },
1553 	{ "alarm_minutes", RTC_MINS_ALARM, RTC_MINS_BCD_MASK,   0, 59 },
1554 	{ "alarm_hours",   RTC_HRS_ALARM,  RTC_HRS_24_BCD_MASK, 0, 23 },
1555 	{ "alarm_mday",    RTC_MDAY_ALARM, RTC_MDAY_ALARM_MASK, 1, 31 },
1556 	{ NULL,            0,              0,                   0,  0 },
1557 };
1558 
1559 static const struct ds1685_rtc_time_regs
1560 ds1685_time_regs_bin_table[] = {
1561 	{ "seconds",       RTC_SECS,       RTC_SECS_BIN_MASK,   0x00, 0x3b },
1562 	{ "minutes",       RTC_MINS,       RTC_MINS_BIN_MASK,   0x00, 0x3b },
1563 	{ "hours",         RTC_HRS,        RTC_HRS_24_BIN_MASK, 0x00, 0x17 },
1564 	{ "wday",          RTC_WDAY,       RTC_WDAY_MASK,       0x01, 0x07 },
1565 	{ "mday",          RTC_MDAY,       RTC_MDAY_BIN_MASK,   0x01, 0x1f },
1566 	{ "month",         RTC_MONTH,      RTC_MONTH_BIN_MASK,  0x01, 0x0c },
1567 	{ "year",          RTC_YEAR,       RTC_YEAR_BIN_MASK,   0x00, 0x63 },
1568 	{ "century",       RTC_CENTURY,    RTC_CENTURY_MASK,    0x00, 0x63 },
1569 	{ "alarm_seconds", RTC_SECS_ALARM, RTC_SECS_BIN_MASK,   0x00, 0x3b },
1570 	{ "alarm_minutes", RTC_MINS_ALARM, RTC_MINS_BIN_MASK,   0x00, 0x3b },
1571 	{ "alarm_hours",   RTC_HRS_ALARM,  RTC_HRS_24_BIN_MASK, 0x00, 0x17 },
1572 	{ "alarm_mday",    RTC_MDAY_ALARM, RTC_MDAY_ALARM_MASK, 0x01, 0x1f },
1573 	{ NULL,            0,              0,                   0x00, 0x00 },
1574 };
1575 
1576 /**
1577  * ds1685_rtc_sysfs_time_regs_bcd_lookup - time/date reg bit lookup function.
1578  * @name: register bit to look up in ds1685_time_regs_bcd_table.
1579  */
1580 static const struct ds1685_rtc_time_regs*
1581 ds1685_rtc_sysfs_time_regs_lookup(const char *name, bool bcd_mode)
1582 {
1583 	const struct ds1685_rtc_time_regs *p;
1584 
1585 	if (bcd_mode)
1586 		p = ds1685_time_regs_bcd_table;
1587 	else
1588 		p = ds1685_time_regs_bin_table;
1589 
1590 	for (; p->name != NULL; ++p)
1591 		if (strcmp(p->name, name) == 0)
1592 			return p;
1593 
1594 	return NULL;
1595 }
1596 
1597 /**
1598  * ds1685_rtc_sysfs_time_regs_show - reads a time/date register via sysfs.
1599  * @dev: pointer to device structure.
1600  * @attr: pointer to device_attribute structure.
1601  * @buf: pointer to char array to hold the output.
1602  */
1603 static ssize_t
1604 ds1685_rtc_sysfs_time_regs_show(struct device *dev,
1605 				struct device_attribute *attr, char *buf)
1606 {
1607 	u8 tmp;
1608 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1609 	const struct ds1685_rtc_time_regs *bcd_reg_info =
1610 		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, true);
1611 	const struct ds1685_rtc_time_regs *bin_reg_info =
1612 		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, false);
1613 
1614 	/* Make sure we actually matched something. */
1615 	if (!bcd_reg_info || !bin_reg_info)
1616 		return -EINVAL;
1617 
1618 	/* bcd_reg_info->reg == bin_reg_info->reg. */
1619 	ds1685_rtc_begin_data_access(rtc);
1620 	tmp = rtc->read(rtc, bcd_reg_info->reg);
1621 	ds1685_rtc_end_data_access(rtc);
1622 
1623 	tmp = ds1685_rtc_bcd2bin(rtc, tmp, bcd_reg_info->mask,
1624 				 bin_reg_info->mask);
1625 
1626 	return snprintf(buf, 4, "%d\n", tmp);
1627 }
1628 
1629 /**
1630  * ds1685_rtc_sysfs_time_regs_store - writes a time/date register via sysfs.
1631  * @dev: pointer to device structure.
1632  * @attr: pointer to device_attribute structure.
1633  * @buf: pointer to char array to hold the output.
1634  * @count: number of bytes written.
1635  */
1636 static ssize_t
1637 ds1685_rtc_sysfs_time_regs_store(struct device *dev,
1638 				 struct device_attribute *attr,
1639 				 const char *buf, size_t count)
1640 {
1641 	long int val = 0;
1642 	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1643 	const struct ds1685_rtc_time_regs *bcd_reg_info =
1644 		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, true);
1645 	const struct ds1685_rtc_time_regs *bin_reg_info =
1646 		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, false);
1647 
1648 	/* We only accept numbers. */
1649 	if (kstrtol(buf, 10, &val) < 0)
1650 		return -EINVAL;
1651 
1652 	/* Make sure we actually matched something. */
1653 	if (!bcd_reg_info || !bin_reg_info)
1654 		return -EINVAL;
1655 
1656 	/* Check for a valid range. */
1657 	if (rtc->bcd_mode) {
1658 		if ((val < bcd_reg_info->min) || (val > bcd_reg_info->max))
1659 			return -ERANGE;
1660 	} else {
1661 		if ((val < bin_reg_info->min) || (val > bin_reg_info->max))
1662 			return -ERANGE;
1663 	}
1664 
1665 	val = ds1685_rtc_bin2bcd(rtc, val, bin_reg_info->mask,
1666 				 bcd_reg_info->mask);
1667 
1668 	/* bcd_reg_info->reg == bin_reg_info->reg. */
1669 	ds1685_rtc_begin_data_access(rtc);
1670 	rtc->write(rtc, bcd_reg_info->reg, val);
1671 	ds1685_rtc_end_data_access(rtc);
1672 
1673 	return count;
1674 }
1675 
1676 /**
1677  * DS1685_RTC_SYSFS_REG_RW - device_attribute for a read-write time register.
1678  * @reg: time/date register to read or write.
1679  */
1680 #define DS1685_RTC_SYSFS_TIME_REG_RW(reg)				\
1681 	static DEVICE_ATTR(reg, S_IRUGO | S_IWUSR,			\
1682 	ds1685_rtc_sysfs_time_regs_show,				\
1683 	ds1685_rtc_sysfs_time_regs_store)
1684 
1685 /*
1686  * Time/Date Register bits.
1687  */
1688 DS1685_RTC_SYSFS_TIME_REG_RW(seconds);
1689 DS1685_RTC_SYSFS_TIME_REG_RW(minutes);
1690 DS1685_RTC_SYSFS_TIME_REG_RW(hours);
1691 DS1685_RTC_SYSFS_TIME_REG_RW(wday);
1692 DS1685_RTC_SYSFS_TIME_REG_RW(mday);
1693 DS1685_RTC_SYSFS_TIME_REG_RW(month);
1694 DS1685_RTC_SYSFS_TIME_REG_RW(year);
1695 DS1685_RTC_SYSFS_TIME_REG_RW(century);
1696 DS1685_RTC_SYSFS_TIME_REG_RW(alarm_seconds);
1697 DS1685_RTC_SYSFS_TIME_REG_RW(alarm_minutes);
1698 DS1685_RTC_SYSFS_TIME_REG_RW(alarm_hours);
1699 DS1685_RTC_SYSFS_TIME_REG_RW(alarm_mday);
1700 
1701 static struct attribute*
1702 ds1685_rtc_sysfs_time_attrs[] = {
1703 	&dev_attr_seconds.attr,
1704 	&dev_attr_minutes.attr,
1705 	&dev_attr_hours.attr,
1706 	&dev_attr_wday.attr,
1707 	&dev_attr_mday.attr,
1708 	&dev_attr_month.attr,
1709 	&dev_attr_year.attr,
1710 	&dev_attr_century.attr,
1711 	NULL,
1712 };
1713 
1714 static const struct attribute_group
1715 ds1685_rtc_sysfs_time_grp = {
1716 	.name = "datetime",
1717 	.attrs = ds1685_rtc_sysfs_time_attrs,
1718 };
1719 
1720 static struct attribute*
1721 ds1685_rtc_sysfs_alarm_attrs[] = {
1722 	&dev_attr_alarm_seconds.attr,
1723 	&dev_attr_alarm_minutes.attr,
1724 	&dev_attr_alarm_hours.attr,
1725 	&dev_attr_alarm_mday.attr,
1726 	NULL,
1727 };
1728 
1729 static const struct attribute_group
1730 ds1685_rtc_sysfs_alarm_grp = {
1731 	.name = "alarm",
1732 	.attrs = ds1685_rtc_sysfs_alarm_attrs,
1733 };
1734 #endif /* CONFIG_RTC_DS1685_SYSFS_REGS */
1735 
1736 
1737 /**
1738  * ds1685_rtc_sysfs_register - register sysfs files.
1739  * @dev: pointer to device structure.
1740  */
1741 static int
1742 ds1685_rtc_sysfs_register(struct device *dev)
1743 {
1744 	int ret = 0;
1745 
1746 	sysfs_bin_attr_init(&ds1685_rtc_sysfs_nvram_attr);
1747 	ret = sysfs_create_bin_file(&dev->kobj, &ds1685_rtc_sysfs_nvram_attr);
1748 	if (ret)
1749 		return ret;
1750 
1751 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_misc_grp);
1752 	if (ret)
1753 		return ret;
1754 
1755 #ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1756 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrla_grp);
1757 	if (ret)
1758 		return ret;
1759 
1760 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlb_grp);
1761 	if (ret)
1762 		return ret;
1763 
1764 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlc_grp);
1765 	if (ret)
1766 		return ret;
1767 
1768 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrld_grp);
1769 	if (ret)
1770 		return ret;
1771 
1772 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4a_grp);
1773 	if (ret)
1774 		return ret;
1775 
1776 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4b_grp);
1777 	if (ret)
1778 		return ret;
1779 
1780 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_time_grp);
1781 	if (ret)
1782 		return ret;
1783 
1784 	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_alarm_grp);
1785 	if (ret)
1786 		return ret;
1787 #endif
1788 	return 0;
1789 }
1790 
1791 /**
1792  * ds1685_rtc_sysfs_unregister - unregister sysfs files.
1793  * @dev: pointer to device structure.
1794  */
1795 static int
1796 ds1685_rtc_sysfs_unregister(struct device *dev)
1797 {
1798 	sysfs_remove_bin_file(&dev->kobj, &ds1685_rtc_sysfs_nvram_attr);
1799 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_misc_grp);
1800 
1801 #ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1802 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrla_grp);
1803 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlb_grp);
1804 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlc_grp);
1805 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrld_grp);
1806 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4a_grp);
1807 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4b_grp);
1808 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_time_grp);
1809 	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_alarm_grp);
1810 #endif
1811 
1812 	return 0;
1813 }
1814 #endif /* CONFIG_SYSFS */
1815 
1816 
1817 
1818 /* ----------------------------------------------------------------------- */
1819 /* Driver Probe/Removal */
1820 
1821 /**
1822  * ds1685_rtc_probe - initializes rtc driver.
1823  * @pdev: pointer to platform_device structure.
1824  */
1825 static int
1826 ds1685_rtc_probe(struct platform_device *pdev)
1827 {
1828 	struct rtc_device *rtc_dev;
1829 	struct resource *res;
1830 	struct ds1685_priv *rtc;
1831 	struct ds1685_rtc_platform_data *pdata;
1832 	u8 ctrla, ctrlb, hours;
1833 	unsigned char am_pm;
1834 	int ret = 0;
1835 
1836 	/* Get the platform data. */
1837 	pdata = (struct ds1685_rtc_platform_data *) pdev->dev.platform_data;
1838 	if (!pdata)
1839 		return -ENODEV;
1840 
1841 	/* Allocate memory for the rtc device. */
1842 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
1843 	if (!rtc)
1844 		return -ENOMEM;
1845 
1846 	/*
1847 	 * Allocate/setup any IORESOURCE_MEM resources, if required.  Not all
1848 	 * platforms put the RTC in an easy-access place.  Like the SGI Octane,
1849 	 * which attaches the RTC to a "ByteBus", hooked to a SuperIO chip
1850 	 * that sits behind the IOC3 PCI metadevice.
1851 	 */
1852 	if (pdata->alloc_io_resources) {
1853 		/* Get the platform resources. */
1854 		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1855 		if (!res)
1856 			return -ENXIO;
1857 		rtc->size = resource_size(res);
1858 
1859 		/* Request a memory region. */
1860 		/* XXX: mmio-only for now. */
1861 		if (!devm_request_mem_region(&pdev->dev, res->start, rtc->size,
1862 					     pdev->name))
1863 			return -EBUSY;
1864 
1865 		/*
1866 		 * Set the base address for the rtc, and ioremap its
1867 		 * registers.
1868 		 */
1869 		rtc->baseaddr = res->start;
1870 		rtc->regs = devm_ioremap(&pdev->dev, res->start, rtc->size);
1871 		if (!rtc->regs)
1872 			return -ENOMEM;
1873 	}
1874 	rtc->alloc_io_resources = pdata->alloc_io_resources;
1875 
1876 	/* Get the register step size. */
1877 	if (pdata->regstep > 0)
1878 		rtc->regstep = pdata->regstep;
1879 	else
1880 		rtc->regstep = 1;
1881 
1882 	/* Platform read function, else default if mmio setup */
1883 	if (pdata->plat_read)
1884 		rtc->read = pdata->plat_read;
1885 	else
1886 		if (pdata->alloc_io_resources)
1887 			rtc->read = ds1685_read;
1888 		else
1889 			return -ENXIO;
1890 
1891 	/* Platform write function, else default if mmio setup */
1892 	if (pdata->plat_write)
1893 		rtc->write = pdata->plat_write;
1894 	else
1895 		if (pdata->alloc_io_resources)
1896 			rtc->write = ds1685_write;
1897 		else
1898 			return -ENXIO;
1899 
1900 	/* Platform pre-shutdown function, if defined. */
1901 	if (pdata->plat_prepare_poweroff)
1902 		rtc->prepare_poweroff = pdata->plat_prepare_poweroff;
1903 
1904 	/* Platform wake_alarm function, if defined. */
1905 	if (pdata->plat_wake_alarm)
1906 		rtc->wake_alarm = pdata->plat_wake_alarm;
1907 
1908 	/* Platform post_ram_clear function, if defined. */
1909 	if (pdata->plat_post_ram_clear)
1910 		rtc->post_ram_clear = pdata->plat_post_ram_clear;
1911 
1912 	/* Init the spinlock, workqueue, & set the driver data. */
1913 	spin_lock_init(&rtc->lock);
1914 	INIT_WORK(&rtc->work, ds1685_rtc_work_queue);
1915 	platform_set_drvdata(pdev, rtc);
1916 
1917 	/* Turn the oscillator on if is not already on (DV1 = 1). */
1918 	ctrla = rtc->read(rtc, RTC_CTRL_A);
1919 	if (!(ctrla & RTC_CTRL_A_DV1))
1920 		ctrla |= RTC_CTRL_A_DV1;
1921 
1922 	/* Enable the countdown chain (DV2 = 0) */
1923 	ctrla &= ~(RTC_CTRL_A_DV2);
1924 
1925 	/* Clear RS3-RS0 in Control A. */
1926 	ctrla &= ~(RTC_CTRL_A_RS_MASK);
1927 
1928 	/*
1929 	 * All done with Control A.  Switch to Bank 1 for the remainder of
1930 	 * the RTC setup so we have access to the extended functions.
1931 	 */
1932 	ctrla |= RTC_CTRL_A_DV0;
1933 	rtc->write(rtc, RTC_CTRL_A, ctrla);
1934 
1935 	/* Default to 32768kHz output. */
1936 	rtc->write(rtc, RTC_EXT_CTRL_4B,
1937 		   (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_E32K));
1938 
1939 	/* Set the SET bit in Control B so we can do some housekeeping. */
1940 	rtc->write(rtc, RTC_CTRL_B,
1941 		   (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
1942 
1943 	/* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
1944 	while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
1945 		cpu_relax();
1946 
1947 	/*
1948 	 * If the platform supports BCD mode, then set DM=0 in Control B.
1949 	 * Otherwise, set DM=1 for BIN mode.
1950 	 */
1951 	ctrlb = rtc->read(rtc, RTC_CTRL_B);
1952 	if (pdata->bcd_mode)
1953 		ctrlb &= ~(RTC_CTRL_B_DM);
1954 	else
1955 		ctrlb |= RTC_CTRL_B_DM;
1956 	rtc->bcd_mode = pdata->bcd_mode;
1957 
1958 	/*
1959 	 * Disable Daylight Savings Time (DSE = 0).
1960 	 * The RTC has hardcoded timezone information that is rendered
1961 	 * obselete.  We'll let the OS deal with DST settings instead.
1962 	 */
1963 	if (ctrlb & RTC_CTRL_B_DSE)
1964 		ctrlb &= ~(RTC_CTRL_B_DSE);
1965 
1966 	/* Force 24-hour mode (2412 = 1). */
1967 	if (!(ctrlb & RTC_CTRL_B_2412)) {
1968 		/* Reinitialize the time hours. */
1969 		hours = rtc->read(rtc, RTC_HRS);
1970 		am_pm = hours & RTC_HRS_AMPM_MASK;
1971 		hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
1972 					   RTC_HRS_12_BIN_MASK);
1973 		hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
1974 
1975 		/* Enable 24-hour mode. */
1976 		ctrlb |= RTC_CTRL_B_2412;
1977 
1978 		/* Write back to Control B, including DM & DSE bits. */
1979 		rtc->write(rtc, RTC_CTRL_B, ctrlb);
1980 
1981 		/* Write the time hours back. */
1982 		rtc->write(rtc, RTC_HRS,
1983 			   ds1685_rtc_bin2bcd(rtc, hours,
1984 					      RTC_HRS_24_BIN_MASK,
1985 					      RTC_HRS_24_BCD_MASK));
1986 
1987 		/* Reinitialize the alarm hours. */
1988 		hours = rtc->read(rtc, RTC_HRS_ALARM);
1989 		am_pm = hours & RTC_HRS_AMPM_MASK;
1990 		hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
1991 					   RTC_HRS_12_BIN_MASK);
1992 		hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
1993 
1994 		/* Write the alarm hours back. */
1995 		rtc->write(rtc, RTC_HRS_ALARM,
1996 			   ds1685_rtc_bin2bcd(rtc, hours,
1997 					      RTC_HRS_24_BIN_MASK,
1998 					      RTC_HRS_24_BCD_MASK));
1999 	} else {
2000 		/* 24-hour mode is already set, so write Control B back. */
2001 		rtc->write(rtc, RTC_CTRL_B, ctrlb);
2002 	}
2003 
2004 	/* Unset the SET bit in Control B so the RTC can update. */
2005 	rtc->write(rtc, RTC_CTRL_B,
2006 		   (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
2007 
2008 	/* Check the main battery. */
2009 	if (!(rtc->read(rtc, RTC_CTRL_D) & RTC_CTRL_D_VRT))
2010 		dev_warn(&pdev->dev,
2011 			 "Main battery is exhausted! RTC may be invalid!\n");
2012 
2013 	/* Check the auxillary battery.  It is optional. */
2014 	if (!(rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_VRT2))
2015 		dev_warn(&pdev->dev,
2016 			 "Aux battery is exhausted or not available.\n");
2017 
2018 	/* Read Ctrl B and clear PIE/AIE/UIE. */
2019 	rtc->write(rtc, RTC_CTRL_B,
2020 		   (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_PAU_MASK)));
2021 
2022 	/* Reading Ctrl C auto-clears PF/AF/UF. */
2023 	rtc->read(rtc, RTC_CTRL_C);
2024 
2025 	/* Read Ctrl 4B and clear RIE/WIE/KSE. */
2026 	rtc->write(rtc, RTC_EXT_CTRL_4B,
2027 		   (rtc->read(rtc, RTC_EXT_CTRL_4B) & ~(RTC_CTRL_4B_RWK_MASK)));
2028 
2029 	/* Clear RF/WF/KF in Ctrl 4A. */
2030 	rtc->write(rtc, RTC_EXT_CTRL_4A,
2031 		   (rtc->read(rtc, RTC_EXT_CTRL_4A) & ~(RTC_CTRL_4A_RWK_MASK)));
2032 
2033 	/*
2034 	 * Re-enable KSE to handle power button events.  We do not enable
2035 	 * WIE or RIE by default.
2036 	 */
2037 	rtc->write(rtc, RTC_EXT_CTRL_4B,
2038 		   (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_KSE));
2039 
2040 	/*
2041 	 * Fetch the IRQ and setup the interrupt handler.
2042 	 *
2043 	 * Not all platforms have the IRQF pin tied to something.  If not, the
2044 	 * RTC will still set the *IE / *F flags and raise IRQF in ctrlc, but
2045 	 * there won't be an automatic way of notifying the kernel about it,
2046 	 * unless ctrlc is explicitly polled.
2047 	 */
2048 	if (!pdata->no_irq) {
2049 		ret = platform_get_irq(pdev, 0);
2050 		if (ret > 0) {
2051 			rtc->irq_num = ret;
2052 
2053 			/* Request an IRQ. */
2054 			ret = devm_request_irq(&pdev->dev, rtc->irq_num,
2055 					       ds1685_rtc_irq_handler,
2056 					       IRQF_SHARED, pdev->name, pdev);
2057 
2058 			/* Check to see if something came back. */
2059 			if (unlikely(ret)) {
2060 				dev_warn(&pdev->dev,
2061 					 "RTC interrupt not available\n");
2062 				rtc->irq_num = 0;
2063 			}
2064 		} else
2065 			return ret;
2066 	}
2067 	rtc->no_irq = pdata->no_irq;
2068 
2069 	/* Setup complete. */
2070 	ds1685_rtc_switch_to_bank0(rtc);
2071 
2072 	/* Register the device as an RTC. */
2073 	rtc_dev = rtc_device_register(pdev->name, &pdev->dev,
2074 				      &ds1685_rtc_ops, THIS_MODULE);
2075 
2076 	/* Success? */
2077 	if (IS_ERR(rtc_dev))
2078 		return PTR_ERR(rtc_dev);
2079 
2080 	/* Maximum periodic rate is 8192Hz (0.122070ms). */
2081 	rtc_dev->max_user_freq = RTC_MAX_USER_FREQ;
2082 
2083 	/* See if the platform doesn't support UIE. */
2084 	if (pdata->uie_unsupported)
2085 		rtc_dev->uie_unsupported = 1;
2086 	rtc->uie_unsupported = pdata->uie_unsupported;
2087 
2088 	rtc->dev = rtc_dev;
2089 
2090 #ifdef CONFIG_SYSFS
2091 	ret = ds1685_rtc_sysfs_register(&pdev->dev);
2092 	if (ret)
2093 		rtc_device_unregister(rtc->dev);
2094 #endif
2095 
2096 	/* Done! */
2097 	return ret;
2098 }
2099 
2100 /**
2101  * ds1685_rtc_remove - removes rtc driver.
2102  * @pdev: pointer to platform_device structure.
2103  */
2104 static int
2105 ds1685_rtc_remove(struct platform_device *pdev)
2106 {
2107 	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
2108 
2109 #ifdef CONFIG_SYSFS
2110 	ds1685_rtc_sysfs_unregister(&pdev->dev);
2111 #endif
2112 
2113 	rtc_device_unregister(rtc->dev);
2114 
2115 	/* Read Ctrl B and clear PIE/AIE/UIE. */
2116 	rtc->write(rtc, RTC_CTRL_B,
2117 		   (rtc->read(rtc, RTC_CTRL_B) &
2118 		    ~(RTC_CTRL_B_PAU_MASK)));
2119 
2120 	/* Reading Ctrl C auto-clears PF/AF/UF. */
2121 	rtc->read(rtc, RTC_CTRL_C);
2122 
2123 	/* Read Ctrl 4B and clear RIE/WIE/KSE. */
2124 	rtc->write(rtc, RTC_EXT_CTRL_4B,
2125 		   (rtc->read(rtc, RTC_EXT_CTRL_4B) &
2126 		    ~(RTC_CTRL_4B_RWK_MASK)));
2127 
2128 	/* Manually clear RF/WF/KF in Ctrl 4A. */
2129 	rtc->write(rtc, RTC_EXT_CTRL_4A,
2130 		   (rtc->read(rtc, RTC_EXT_CTRL_4A) &
2131 		    ~(RTC_CTRL_4A_RWK_MASK)));
2132 
2133 	cancel_work_sync(&rtc->work);
2134 
2135 	return 0;
2136 }
2137 
2138 /**
2139  * ds1685_rtc_driver - rtc driver properties.
2140  */
2141 static struct platform_driver ds1685_rtc_driver = {
2142 	.driver		= {
2143 		.name	= "rtc-ds1685",
2144 	},
2145 	.probe		= ds1685_rtc_probe,
2146 	.remove		= ds1685_rtc_remove,
2147 };
2148 
2149 /**
2150  * ds1685_rtc_init - rtc module init.
2151  */
2152 static int __init
2153 ds1685_rtc_init(void)
2154 {
2155 	return platform_driver_register(&ds1685_rtc_driver);
2156 }
2157 
2158 /**
2159  * ds1685_rtc_exit - rtc module exit.
2160  */
2161 static void __exit
2162 ds1685_rtc_exit(void)
2163 {
2164 	platform_driver_unregister(&ds1685_rtc_driver);
2165 }
2166 
2167 module_init(ds1685_rtc_init);
2168 module_exit(ds1685_rtc_exit);
2169 /* ----------------------------------------------------------------------- */
2170 
2171 
2172 /* ----------------------------------------------------------------------- */
2173 /* Poweroff function */
2174 
2175 /**
2176  * ds1685_rtc_poweroff - uses the RTC chip to power the system off.
2177  * @pdev: pointer to platform_device structure.
2178  */
2179 void __noreturn
2180 ds1685_rtc_poweroff(struct platform_device *pdev)
2181 {
2182 	u8 ctrla, ctrl4a, ctrl4b;
2183 	struct ds1685_priv *rtc;
2184 
2185 	/* Check for valid RTC data, else, spin forever. */
2186 	if (unlikely(!pdev)) {
2187 		pr_emerg("platform device data not available, spinning forever ...\n");
2188 		unreachable();
2189 	} else {
2190 		/* Get the rtc data. */
2191 		rtc = platform_get_drvdata(pdev);
2192 
2193 		/*
2194 		 * Disable our IRQ.  We're powering down, so we're not
2195 		 * going to worry about cleaning up.  Most of that should
2196 		 * have been taken care of by the shutdown scripts and this
2197 		 * is the final function call.
2198 		 */
2199 		if (!rtc->no_irq)
2200 			disable_irq_nosync(rtc->irq_num);
2201 
2202 		/* Oscillator must be on and the countdown chain enabled. */
2203 		ctrla = rtc->read(rtc, RTC_CTRL_A);
2204 		ctrla |= RTC_CTRL_A_DV1;
2205 		ctrla &= ~(RTC_CTRL_A_DV2);
2206 		rtc->write(rtc, RTC_CTRL_A, ctrla);
2207 
2208 		/*
2209 		 * Read Control 4A and check the status of the auxillary
2210 		 * battery.  This must be present and working (VRT2 = 1)
2211 		 * for wakeup and kickstart functionality to be useful.
2212 		 */
2213 		ds1685_rtc_switch_to_bank1(rtc);
2214 		ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
2215 		if (ctrl4a & RTC_CTRL_4A_VRT2) {
2216 			/* Clear all of the interrupt flags on Control 4A. */
2217 			ctrl4a &= ~(RTC_CTRL_4A_RWK_MASK);
2218 			rtc->write(rtc, RTC_EXT_CTRL_4A, ctrl4a);
2219 
2220 			/*
2221 			 * The auxillary battery is present and working.
2222 			 * Enable extended functions (ABE=1), enable
2223 			 * wake-up (WIE=1), and enable kickstart (KSE=1)
2224 			 * in Control 4B.
2225 			 */
2226 			ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
2227 			ctrl4b |= (RTC_CTRL_4B_ABE | RTC_CTRL_4B_WIE |
2228 				   RTC_CTRL_4B_KSE);
2229 			rtc->write(rtc, RTC_EXT_CTRL_4B, ctrl4b);
2230 		}
2231 
2232 		/* Set PAB to 1 in Control 4A to power the system down. */
2233 		dev_warn(&pdev->dev, "Powerdown.\n");
2234 		msleep(20);
2235 		rtc->write(rtc, RTC_EXT_CTRL_4A,
2236 			   (ctrl4a | RTC_CTRL_4A_PAB));
2237 
2238 		/* Spin ... we do not switch back to bank0. */
2239 		unreachable();
2240 	}
2241 }
2242 EXPORT_SYMBOL(ds1685_rtc_poweroff);
2243 /* ----------------------------------------------------------------------- */
2244 
2245 
2246 MODULE_AUTHOR("Joshua Kinard <kumba@gentoo.org>");
2247 MODULE_AUTHOR("Matthias Fuchs <matthias.fuchs@esd-electronics.com>");
2248 MODULE_DESCRIPTION("Dallas/Maxim DS1685/DS1687-series RTC driver");
2249 MODULE_LICENSE("GPL");
2250 MODULE_VERSION(DRV_VERSION);
2251 MODULE_ALIAS("platform:rtc-ds1685");
2252