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 */
46static u8
47ds1685_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 */
59static void
60ds1685_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 */
80static inline u8
81ds1685_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 */
98static inline u8
99ds1685_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 */
111static inline void
112ds1685_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 */
122static inline void
123ds1685_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 */
142static inline void
143ds1685_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 */
165static inline void
166ds1685_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 */
189static inline void
190ds1685_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 */
205static inline void
206ds1685_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 */
226static inline void
227ds1685_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 */
249static int
250ds1685_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 */
299static int
300ds1685_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 */
376static int
377ds1685_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 */
444static int
445ds1685_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 */
538static int
539ds1685_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 */
572static irqreturn_t
573ds1685_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 */
646static void
647ds1685_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 */
752static 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 */
761static 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 */
775static char*
776ds1685_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 */
798static int
799ds1685_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
912static const struct rtc_class_ops
913ds1685_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 */
937static ssize_t
938ds1685_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 */
1017static ssize_t
1018ds1685_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 */
1090static struct bin_attribute
1091ds1685_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 */
1107static ssize_t
1108ds1685_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}
1120static 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 */
1128static ssize_t
1129ds1685_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}
1143static 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 */
1151static ssize_t
1152ds1685_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}
1169static 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 */
1174static struct attribute*
1175ds1685_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 */
1185static const struct attribute_group
1186ds1685_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 */
1198struct 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 */
1207static const struct ds1685_rtc_ctrl_regs
1208ds1685_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 */
1254static const struct ds1685_rtc_ctrl_regs*
1255ds1685_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 */
1272static ssize_t
1273ds1685_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 */
1300static ssize_t
1301ds1685_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 */
1356DS1685_RTC_SYSFS_CTRL_REG_RO(uip);
1357DS1685_RTC_SYSFS_CTRL_REG_RW(dv2);
1358DS1685_RTC_SYSFS_CTRL_REG_RW(dv1);
1359DS1685_RTC_SYSFS_CTRL_REG_RO(dv0);
1360DS1685_RTC_SYSFS_CTRL_REG_RW(rs3);
1361DS1685_RTC_SYSFS_CTRL_REG_RW(rs2);
1362DS1685_RTC_SYSFS_CTRL_REG_RW(rs1);
1363DS1685_RTC_SYSFS_CTRL_REG_RW(rs0);
1364
1365static struct attribute*
1366ds1685_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
1378static const struct attribute_group
1379ds1685_rtc_sysfs_ctrla_grp = {
1380	.name = "ctrla",
1381	.attrs = ds1685_rtc_sysfs_ctrla_attrs,
1382};
1383
1384
1385/*
1386 * Control Register B bits.
1387 */
1388DS1685_RTC_SYSFS_CTRL_REG_RO(set);
1389DS1685_RTC_SYSFS_CTRL_REG_RW(pie);
1390DS1685_RTC_SYSFS_CTRL_REG_RW(aie);
1391DS1685_RTC_SYSFS_CTRL_REG_RW(uie);
1392DS1685_RTC_SYSFS_CTRL_REG_RW(sqwe);
1393DS1685_RTC_SYSFS_CTRL_REG_RO(dm);
1394DS1685_RTC_SYSFS_CTRL_REG_RO(2412);
1395DS1685_RTC_SYSFS_CTRL_REG_RO(dse);
1396
1397static struct attribute*
1398ds1685_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
1410static const struct attribute_group
1411ds1685_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 */
1423DS1685_RTC_SYSFS_CTRL_REG_RO(irqf);
1424DS1685_RTC_SYSFS_CTRL_REG_RO(pf);
1425DS1685_RTC_SYSFS_CTRL_REG_RO(af);
1426DS1685_RTC_SYSFS_CTRL_REG_RO(uf);
1427
1428static struct attribute*
1429ds1685_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
1437static const struct attribute_group
1438ds1685_rtc_sysfs_ctrlc_grp = {
1439	.name = "ctrlc",
1440	.attrs = ds1685_rtc_sysfs_ctrlc_attrs,
1441};
1442
1443/*
1444 * Control Register D bits.
1445 */
1446DS1685_RTC_SYSFS_CTRL_REG_RO(vrt);
1447
1448static struct attribute*
1449ds1685_rtc_sysfs_ctrld_attrs[] = {
1450	&dev_attr_vrt.attr,
1451	NULL,
1452};
1453
1454static const struct attribute_group
1455ds1685_rtc_sysfs_ctrld_grp = {
1456	.name = "ctrld",
1457	.attrs = ds1685_rtc_sysfs_ctrld_attrs,
1458};
1459
1460/*
1461 * Control Register 4A bits.
1462 */
1463DS1685_RTC_SYSFS_CTRL_REG_RO(vrt2);
1464DS1685_RTC_SYSFS_CTRL_REG_RO(incr);
1465DS1685_RTC_SYSFS_CTRL_REG_RW(pab);
1466DS1685_RTC_SYSFS_CTRL_REG_RW(rf);
1467DS1685_RTC_SYSFS_CTRL_REG_RW(wf);
1468DS1685_RTC_SYSFS_CTRL_REG_RW(kf);
1469#if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1470DS1685_RTC_SYSFS_CTRL_REG_RO(bme);
1471#endif
1472
1473static struct attribute*
1474ds1685_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
1487static const struct attribute_group
1488ds1685_rtc_sysfs_ctrl4a_grp = {
1489	.name = "ctrl4a",
1490	.attrs = ds1685_rtc_sysfs_ctrl4a_attrs,
1491};
1492
1493/*
1494 * Control Register 4B bits.
1495 */
1496DS1685_RTC_SYSFS_CTRL_REG_RW(abe);
1497DS1685_RTC_SYSFS_CTRL_REG_RW(e32k);
1498DS1685_RTC_SYSFS_CTRL_REG_RO(cs);
1499DS1685_RTC_SYSFS_CTRL_REG_RW(rce);
1500DS1685_RTC_SYSFS_CTRL_REG_RW(prs);
1501DS1685_RTC_SYSFS_CTRL_REG_RW(rie);
1502DS1685_RTC_SYSFS_CTRL_REG_RW(wie);
1503DS1685_RTC_SYSFS_CTRL_REG_RW(kse);
1504
1505static struct attribute*
1506ds1685_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
1518static const struct attribute_group
1519ds1685_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 */
1531struct 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 */
1542static const struct ds1685_rtc_time_regs
1543ds1685_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
1559static const struct ds1685_rtc_time_regs
1560ds1685_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 */
1580static const struct ds1685_rtc_time_regs*
1581ds1685_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 */
1603static ssize_t
1604ds1685_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 */
1636static ssize_t
1637ds1685_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 */
1688DS1685_RTC_SYSFS_TIME_REG_RW(seconds);
1689DS1685_RTC_SYSFS_TIME_REG_RW(minutes);
1690DS1685_RTC_SYSFS_TIME_REG_RW(hours);
1691DS1685_RTC_SYSFS_TIME_REG_RW(wday);
1692DS1685_RTC_SYSFS_TIME_REG_RW(mday);
1693DS1685_RTC_SYSFS_TIME_REG_RW(month);
1694DS1685_RTC_SYSFS_TIME_REG_RW(year);
1695DS1685_RTC_SYSFS_TIME_REG_RW(century);
1696DS1685_RTC_SYSFS_TIME_REG_RW(alarm_seconds);
1697DS1685_RTC_SYSFS_TIME_REG_RW(alarm_minutes);
1698DS1685_RTC_SYSFS_TIME_REG_RW(alarm_hours);
1699DS1685_RTC_SYSFS_TIME_REG_RW(alarm_mday);
1700
1701static struct attribute*
1702ds1685_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
1714static const struct attribute_group
1715ds1685_rtc_sysfs_time_grp = {
1716	.name = "datetime",
1717	.attrs = ds1685_rtc_sysfs_time_attrs,
1718};
1719
1720static struct attribute*
1721ds1685_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
1729static const struct attribute_group
1730ds1685_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 */
1741static int
1742ds1685_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 */
1795static int
1796ds1685_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 */
1825static int
1826ds1685_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 */
2104static int
2105ds1685_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 */
2141static 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 */
2152static int __init
2153ds1685_rtc_init(void)
2154{
2155	return platform_driver_register(&ds1685_rtc_driver);
2156}
2157
2158/**
2159 * ds1685_rtc_exit - rtc module exit.
2160 */
2161static void __exit
2162ds1685_rtc_exit(void)
2163{
2164	platform_driver_unregister(&ds1685_rtc_driver);
2165}
2166
2167module_init(ds1685_rtc_init);
2168module_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 */
2179void __noreturn
2180ds1685_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}
2242EXPORT_SYMBOL(ds1685_rtc_poweroff);
2243/* ----------------------------------------------------------------------- */
2244
2245
2246MODULE_AUTHOR("Joshua Kinard <kumba@gentoo.org>");
2247MODULE_AUTHOR("Matthias Fuchs <matthias.fuchs@esd-electronics.com>");
2248MODULE_DESCRIPTION("Dallas/Maxim DS1685/DS1687-series RTC driver");
2249MODULE_LICENSE("GPL");
2250MODULE_VERSION(DRV_VERSION);
2251MODULE_ALIAS("platform:rtc-ds1685");
2252