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: %8phC\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: %8phC\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,
 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);
 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 sprintf(buf, "%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 sprintf(buf, "%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 sprintf(buf, "%8phC\n", ssn);
1164}
1165static DEVICE_ATTR(serial, S_IRUGO, ds1685_rtc_sysfs_serial_show, NULL);
1166
1167/**
1168 * struct ds1685_rtc_sysfs_misc_attrs - list for misc RTC features.
1169 */
1170static struct attribute*
1171ds1685_rtc_sysfs_misc_attrs[] = {
1172	&dev_attr_battery.attr,
1173	&dev_attr_auxbatt.attr,
1174	&dev_attr_serial.attr,
1175	NULL,
1176};
1177
1178/**
1179 * struct ds1685_rtc_sysfs_misc_grp - attr group for misc RTC features.
1180 */
1181static const struct attribute_group
1182ds1685_rtc_sysfs_misc_grp = {
1183	.name = "misc",
1184	.attrs = ds1685_rtc_sysfs_misc_attrs,
1185};
1186
1187#ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1188/**
1189 * struct ds1685_rtc_ctrl_regs.
1190 * @name: char pointer for the bit name.
1191 * @reg: control register the bit is in.
1192 * @bit: the bit's offset in the register.
1193 */
1194struct ds1685_rtc_ctrl_regs {
1195	const char *name;
1196	const u8 reg;
1197	const u8 bit;
1198};
1199
1200/*
1201 * Ctrl register bit lookup table.
1202 */
1203static const struct ds1685_rtc_ctrl_regs
1204ds1685_ctrl_regs_table[] = {
1205	{ "uip",  RTC_CTRL_A,      RTC_CTRL_A_UIP   },
1206	{ "dv2",  RTC_CTRL_A,      RTC_CTRL_A_DV2   },
1207	{ "dv1",  RTC_CTRL_A,      RTC_CTRL_A_DV1   },
1208	{ "dv0",  RTC_CTRL_A,      RTC_CTRL_A_DV0   },
1209	{ "rs3",  RTC_CTRL_A,      RTC_CTRL_A_RS3   },
1210	{ "rs2",  RTC_CTRL_A,      RTC_CTRL_A_RS2   },
1211	{ "rs1",  RTC_CTRL_A,      RTC_CTRL_A_RS1   },
1212	{ "rs0",  RTC_CTRL_A,      RTC_CTRL_A_RS0   },
1213	{ "set",  RTC_CTRL_B,      RTC_CTRL_B_SET   },
1214	{ "pie",  RTC_CTRL_B,      RTC_CTRL_B_PIE   },
1215	{ "aie",  RTC_CTRL_B,      RTC_CTRL_B_AIE   },
1216	{ "uie",  RTC_CTRL_B,      RTC_CTRL_B_UIE   },
1217	{ "sqwe", RTC_CTRL_B,      RTC_CTRL_B_SQWE  },
1218	{ "dm",   RTC_CTRL_B,      RTC_CTRL_B_DM    },
1219	{ "2412", RTC_CTRL_B,      RTC_CTRL_B_2412  },
1220	{ "dse",  RTC_CTRL_B,      RTC_CTRL_B_DSE   },
1221	{ "irqf", RTC_CTRL_C,      RTC_CTRL_C_IRQF  },
1222	{ "pf",   RTC_CTRL_C,      RTC_CTRL_C_PF    },
1223	{ "af",   RTC_CTRL_C,      RTC_CTRL_C_AF    },
1224	{ "uf",   RTC_CTRL_C,      RTC_CTRL_C_UF    },
1225	{ "vrt",  RTC_CTRL_D,      RTC_CTRL_D_VRT   },
1226	{ "vrt2", RTC_EXT_CTRL_4A, RTC_CTRL_4A_VRT2 },
1227	{ "incr", RTC_EXT_CTRL_4A, RTC_CTRL_4A_INCR },
1228	{ "pab",  RTC_EXT_CTRL_4A, RTC_CTRL_4A_PAB  },
1229	{ "rf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_RF   },
1230	{ "wf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_WF   },
1231	{ "kf",   RTC_EXT_CTRL_4A, RTC_CTRL_4A_KF   },
1232#if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1233	{ "bme",  RTC_EXT_CTRL_4A, RTC_CTRL_4A_BME  },
1234#endif
1235	{ "abe",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_ABE  },
1236	{ "e32k", RTC_EXT_CTRL_4B, RTC_CTRL_4B_E32K },
1237	{ "cs",   RTC_EXT_CTRL_4B, RTC_CTRL_4B_CS   },
1238	{ "rce",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_RCE  },
1239	{ "prs",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_PRS  },
1240	{ "rie",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_RIE  },
1241	{ "wie",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_WIE  },
1242	{ "kse",  RTC_EXT_CTRL_4B, RTC_CTRL_4B_KSE  },
1243	{ NULL,   0,               0                },
1244};
1245
1246/**
1247 * ds1685_rtc_sysfs_ctrl_regs_lookup - ctrl register bit lookup function.
1248 * @name: ctrl register bit to look up in ds1685_ctrl_regs_table.
1249 */
1250static const struct ds1685_rtc_ctrl_regs*
1251ds1685_rtc_sysfs_ctrl_regs_lookup(const char *name)
1252{
1253	const struct ds1685_rtc_ctrl_regs *p = ds1685_ctrl_regs_table;
1254
1255	for (; p->name != NULL; ++p)
1256		if (strcmp(p->name, name) == 0)
1257			return p;
1258
1259	return NULL;
1260}
1261
1262/**
1263 * ds1685_rtc_sysfs_ctrl_regs_show - reads a ctrl register bit via sysfs.
1264 * @dev: pointer to device structure.
1265 * @attr: pointer to device_attribute structure.
1266 * @buf: pointer to char array to hold the output.
1267 */
1268static ssize_t
1269ds1685_rtc_sysfs_ctrl_regs_show(struct device *dev,
1270				struct device_attribute *attr, char *buf)
1271{
1272	u8 tmp;
1273	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1274	const struct ds1685_rtc_ctrl_regs *reg_info =
1275		ds1685_rtc_sysfs_ctrl_regs_lookup(attr->attr.name);
1276
1277	/* Make sure we actually matched something. */
1278	if (!reg_info)
1279		return -EINVAL;
1280
1281	/* No spinlock during a read -- mutex is already held. */
1282	ds1685_rtc_switch_to_bank1(rtc);
1283	tmp = rtc->read(rtc, reg_info->reg) & reg_info->bit;
1284	ds1685_rtc_switch_to_bank0(rtc);
1285
1286	return sprintf(buf, "%d\n", (tmp ? 1 : 0));
1287}
1288
1289/**
1290 * ds1685_rtc_sysfs_ctrl_regs_store - writes a ctrl register bit via sysfs.
1291 * @dev: pointer to device structure.
1292 * @attr: pointer to device_attribute structure.
1293 * @buf: pointer to char array to hold the output.
1294 * @count: number of bytes written.
1295 */
1296static ssize_t
1297ds1685_rtc_sysfs_ctrl_regs_store(struct device *dev,
1298				 struct device_attribute *attr,
1299				 const char *buf, size_t count)
1300{
1301	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1302	u8 reg = 0, bit = 0, tmp;
1303	unsigned long flags;
1304	long int val = 0;
1305	const struct ds1685_rtc_ctrl_regs *reg_info =
1306		ds1685_rtc_sysfs_ctrl_regs_lookup(attr->attr.name);
1307
1308	/* We only accept numbers. */
1309	if (kstrtol(buf, 10, &val) < 0)
1310		return -EINVAL;
1311
1312	/* bits are binary, 0 or 1 only. */
1313	if ((val != 0) && (val != 1))
1314		return -ERANGE;
1315
1316	/* Make sure we actually matched something. */
1317	if (!reg_info)
1318		return -EINVAL;
1319
1320	reg = reg_info->reg;
1321	bit = reg_info->bit;
1322
1323	/* Safe to spinlock during a write. */
1324	ds1685_rtc_begin_ctrl_access(rtc, &flags);
1325	tmp = rtc->read(rtc, reg);
1326	rtc->write(rtc, reg, (val ? (tmp | bit) : (tmp & ~(bit))));
1327	ds1685_rtc_end_ctrl_access(rtc, flags);
1328
1329	return count;
1330}
1331
1332/**
1333 * DS1685_RTC_SYSFS_CTRL_REG_RO - device_attribute for read-only register bit.
1334 * @bit: bit to read.
1335 */
1336#define DS1685_RTC_SYSFS_CTRL_REG_RO(bit)				\
1337	static DEVICE_ATTR(bit, S_IRUGO,				\
1338	ds1685_rtc_sysfs_ctrl_regs_show, NULL)
1339
1340/**
1341 * DS1685_RTC_SYSFS_CTRL_REG_RW - device_attribute for read-write register bit.
1342 * @bit: bit to read or write.
1343 */
1344#define DS1685_RTC_SYSFS_CTRL_REG_RW(bit)				\
1345	static DEVICE_ATTR(bit, S_IRUGO | S_IWUSR,			\
1346	ds1685_rtc_sysfs_ctrl_regs_show,				\
1347	ds1685_rtc_sysfs_ctrl_regs_store)
1348
1349/*
1350 * Control Register A bits.
1351 */
1352DS1685_RTC_SYSFS_CTRL_REG_RO(uip);
1353DS1685_RTC_SYSFS_CTRL_REG_RW(dv2);
1354DS1685_RTC_SYSFS_CTRL_REG_RW(dv1);
1355DS1685_RTC_SYSFS_CTRL_REG_RO(dv0);
1356DS1685_RTC_SYSFS_CTRL_REG_RW(rs3);
1357DS1685_RTC_SYSFS_CTRL_REG_RW(rs2);
1358DS1685_RTC_SYSFS_CTRL_REG_RW(rs1);
1359DS1685_RTC_SYSFS_CTRL_REG_RW(rs0);
1360
1361static struct attribute*
1362ds1685_rtc_sysfs_ctrla_attrs[] = {
1363	&dev_attr_uip.attr,
1364	&dev_attr_dv2.attr,
1365	&dev_attr_dv1.attr,
1366	&dev_attr_dv0.attr,
1367	&dev_attr_rs3.attr,
1368	&dev_attr_rs2.attr,
1369	&dev_attr_rs1.attr,
1370	&dev_attr_rs0.attr,
1371	NULL,
1372};
1373
1374static const struct attribute_group
1375ds1685_rtc_sysfs_ctrla_grp = {
1376	.name = "ctrla",
1377	.attrs = ds1685_rtc_sysfs_ctrla_attrs,
1378};
1379
1380
1381/*
1382 * Control Register B bits.
1383 */
1384DS1685_RTC_SYSFS_CTRL_REG_RO(set);
1385DS1685_RTC_SYSFS_CTRL_REG_RW(pie);
1386DS1685_RTC_SYSFS_CTRL_REG_RW(aie);
1387DS1685_RTC_SYSFS_CTRL_REG_RW(uie);
1388DS1685_RTC_SYSFS_CTRL_REG_RW(sqwe);
1389DS1685_RTC_SYSFS_CTRL_REG_RO(dm);
1390DS1685_RTC_SYSFS_CTRL_REG_RO(2412);
1391DS1685_RTC_SYSFS_CTRL_REG_RO(dse);
1392
1393static struct attribute*
1394ds1685_rtc_sysfs_ctrlb_attrs[] = {
1395	&dev_attr_set.attr,
1396	&dev_attr_pie.attr,
1397	&dev_attr_aie.attr,
1398	&dev_attr_uie.attr,
1399	&dev_attr_sqwe.attr,
1400	&dev_attr_dm.attr,
1401	&dev_attr_2412.attr,
1402	&dev_attr_dse.attr,
1403	NULL,
1404};
1405
1406static const struct attribute_group
1407ds1685_rtc_sysfs_ctrlb_grp = {
1408	.name = "ctrlb",
1409	.attrs = ds1685_rtc_sysfs_ctrlb_attrs,
1410};
1411
1412/*
1413 * Control Register C bits.
1414 *
1415 * Reading Control C clears these bits!  Reading them individually can
1416 * possibly cause an interrupt to be missed.  Use the /proc interface
1417 * to see all the bits in this register simultaneously.
1418 */
1419DS1685_RTC_SYSFS_CTRL_REG_RO(irqf);
1420DS1685_RTC_SYSFS_CTRL_REG_RO(pf);
1421DS1685_RTC_SYSFS_CTRL_REG_RO(af);
1422DS1685_RTC_SYSFS_CTRL_REG_RO(uf);
1423
1424static struct attribute*
1425ds1685_rtc_sysfs_ctrlc_attrs[] = {
1426	&dev_attr_irqf.attr,
1427	&dev_attr_pf.attr,
1428	&dev_attr_af.attr,
1429	&dev_attr_uf.attr,
1430	NULL,
1431};
1432
1433static const struct attribute_group
1434ds1685_rtc_sysfs_ctrlc_grp = {
1435	.name = "ctrlc",
1436	.attrs = ds1685_rtc_sysfs_ctrlc_attrs,
1437};
1438
1439/*
1440 * Control Register D bits.
1441 */
1442DS1685_RTC_SYSFS_CTRL_REG_RO(vrt);
1443
1444static struct attribute*
1445ds1685_rtc_sysfs_ctrld_attrs[] = {
1446	&dev_attr_vrt.attr,
1447	NULL,
1448};
1449
1450static const struct attribute_group
1451ds1685_rtc_sysfs_ctrld_grp = {
1452	.name = "ctrld",
1453	.attrs = ds1685_rtc_sysfs_ctrld_attrs,
1454};
1455
1456/*
1457 * Control Register 4A bits.
1458 */
1459DS1685_RTC_SYSFS_CTRL_REG_RO(vrt2);
1460DS1685_RTC_SYSFS_CTRL_REG_RO(incr);
1461DS1685_RTC_SYSFS_CTRL_REG_RW(pab);
1462DS1685_RTC_SYSFS_CTRL_REG_RW(rf);
1463DS1685_RTC_SYSFS_CTRL_REG_RW(wf);
1464DS1685_RTC_SYSFS_CTRL_REG_RW(kf);
1465#if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1466DS1685_RTC_SYSFS_CTRL_REG_RO(bme);
1467#endif
1468
1469static struct attribute*
1470ds1685_rtc_sysfs_ctrl4a_attrs[] = {
1471	&dev_attr_vrt2.attr,
1472	&dev_attr_incr.attr,
1473	&dev_attr_pab.attr,
1474	&dev_attr_rf.attr,
1475	&dev_attr_wf.attr,
1476	&dev_attr_kf.attr,
1477#if !defined(CONFIG_RTC_DRV_DS1685) && !defined(CONFIG_RTC_DRV_DS1689)
1478	&dev_attr_bme.attr,
1479#endif
1480	NULL,
1481};
1482
1483static const struct attribute_group
1484ds1685_rtc_sysfs_ctrl4a_grp = {
1485	.name = "ctrl4a",
1486	.attrs = ds1685_rtc_sysfs_ctrl4a_attrs,
1487};
1488
1489/*
1490 * Control Register 4B bits.
1491 */
1492DS1685_RTC_SYSFS_CTRL_REG_RW(abe);
1493DS1685_RTC_SYSFS_CTRL_REG_RW(e32k);
1494DS1685_RTC_SYSFS_CTRL_REG_RO(cs);
1495DS1685_RTC_SYSFS_CTRL_REG_RW(rce);
1496DS1685_RTC_SYSFS_CTRL_REG_RW(prs);
1497DS1685_RTC_SYSFS_CTRL_REG_RW(rie);
1498DS1685_RTC_SYSFS_CTRL_REG_RW(wie);
1499DS1685_RTC_SYSFS_CTRL_REG_RW(kse);
1500
1501static struct attribute*
1502ds1685_rtc_sysfs_ctrl4b_attrs[] = {
1503	&dev_attr_abe.attr,
1504	&dev_attr_e32k.attr,
1505	&dev_attr_cs.attr,
1506	&dev_attr_rce.attr,
1507	&dev_attr_prs.attr,
1508	&dev_attr_rie.attr,
1509	&dev_attr_wie.attr,
1510	&dev_attr_kse.attr,
1511	NULL,
1512};
1513
1514static const struct attribute_group
1515ds1685_rtc_sysfs_ctrl4b_grp = {
1516	.name = "ctrl4b",
1517	.attrs = ds1685_rtc_sysfs_ctrl4b_attrs,
1518};
1519
1520
1521/**
1522 * struct ds1685_rtc_ctrl_regs.
1523 * @name: char pointer for the bit name.
1524 * @reg: control register the bit is in.
1525 * @bit: the bit's offset in the register.
1526 */
1527struct ds1685_rtc_time_regs {
1528	const char *name;
1529	const u8 reg;
1530	const u8 mask;
1531	const u8 min;
1532	const u8 max;
1533};
1534
1535/*
1536 * Time/Date register lookup tables.
1537 */
1538static const struct ds1685_rtc_time_regs
1539ds1685_time_regs_bcd_table[] = {
1540	{ "seconds",       RTC_SECS,       RTC_SECS_BCD_MASK,   0, 59 },
1541	{ "minutes",       RTC_MINS,       RTC_MINS_BCD_MASK,   0, 59 },
1542	{ "hours",         RTC_HRS,        RTC_HRS_24_BCD_MASK, 0, 23 },
1543	{ "wday",          RTC_WDAY,       RTC_WDAY_MASK,       1,  7 },
1544	{ "mday",          RTC_MDAY,       RTC_MDAY_BCD_MASK,   1, 31 },
1545	{ "month",         RTC_MONTH,      RTC_MONTH_BCD_MASK,  1, 12 },
1546	{ "year",          RTC_YEAR,       RTC_YEAR_BCD_MASK,   0, 99 },
1547	{ "century",       RTC_CENTURY,    RTC_CENTURY_MASK,    0, 99 },
1548	{ "alarm_seconds", RTC_SECS_ALARM, RTC_SECS_BCD_MASK,   0, 59 },
1549	{ "alarm_minutes", RTC_MINS_ALARM, RTC_MINS_BCD_MASK,   0, 59 },
1550	{ "alarm_hours",   RTC_HRS_ALARM,  RTC_HRS_24_BCD_MASK, 0, 23 },
1551	{ "alarm_mday",    RTC_MDAY_ALARM, RTC_MDAY_ALARM_MASK, 1, 31 },
1552	{ NULL,            0,              0,                   0,  0 },
1553};
1554
1555static const struct ds1685_rtc_time_regs
1556ds1685_time_regs_bin_table[] = {
1557	{ "seconds",       RTC_SECS,       RTC_SECS_BIN_MASK,   0x00, 0x3b },
1558	{ "minutes",       RTC_MINS,       RTC_MINS_BIN_MASK,   0x00, 0x3b },
1559	{ "hours",         RTC_HRS,        RTC_HRS_24_BIN_MASK, 0x00, 0x17 },
1560	{ "wday",          RTC_WDAY,       RTC_WDAY_MASK,       0x01, 0x07 },
1561	{ "mday",          RTC_MDAY,       RTC_MDAY_BIN_MASK,   0x01, 0x1f },
1562	{ "month",         RTC_MONTH,      RTC_MONTH_BIN_MASK,  0x01, 0x0c },
1563	{ "year",          RTC_YEAR,       RTC_YEAR_BIN_MASK,   0x00, 0x63 },
1564	{ "century",       RTC_CENTURY,    RTC_CENTURY_MASK,    0x00, 0x63 },
1565	{ "alarm_seconds", RTC_SECS_ALARM, RTC_SECS_BIN_MASK,   0x00, 0x3b },
1566	{ "alarm_minutes", RTC_MINS_ALARM, RTC_MINS_BIN_MASK,   0x00, 0x3b },
1567	{ "alarm_hours",   RTC_HRS_ALARM,  RTC_HRS_24_BIN_MASK, 0x00, 0x17 },
1568	{ "alarm_mday",    RTC_MDAY_ALARM, RTC_MDAY_ALARM_MASK, 0x01, 0x1f },
1569	{ NULL,            0,              0,                   0x00, 0x00 },
1570};
1571
1572/**
1573 * ds1685_rtc_sysfs_time_regs_bcd_lookup - time/date reg bit lookup function.
1574 * @name: register bit to look up in ds1685_time_regs_bcd_table.
1575 */
1576static const struct ds1685_rtc_time_regs*
1577ds1685_rtc_sysfs_time_regs_lookup(const char *name, bool bcd_mode)
1578{
1579	const struct ds1685_rtc_time_regs *p;
1580
1581	if (bcd_mode)
1582		p = ds1685_time_regs_bcd_table;
1583	else
1584		p = ds1685_time_regs_bin_table;
1585
1586	for (; p->name != NULL; ++p)
1587		if (strcmp(p->name, name) == 0)
1588			return p;
1589
1590	return NULL;
1591}
1592
1593/**
1594 * ds1685_rtc_sysfs_time_regs_show - reads a time/date register via sysfs.
1595 * @dev: pointer to device structure.
1596 * @attr: pointer to device_attribute structure.
1597 * @buf: pointer to char array to hold the output.
1598 */
1599static ssize_t
1600ds1685_rtc_sysfs_time_regs_show(struct device *dev,
1601				struct device_attribute *attr, char *buf)
1602{
1603	u8 tmp;
1604	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1605	const struct ds1685_rtc_time_regs *bcd_reg_info =
1606		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, true);
1607	const struct ds1685_rtc_time_regs *bin_reg_info =
1608		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, false);
1609
1610	/* Make sure we actually matched something. */
1611	if (!bcd_reg_info || !bin_reg_info)
1612		return -EINVAL;
1613
1614	/* bcd_reg_info->reg == bin_reg_info->reg. */
1615	ds1685_rtc_begin_data_access(rtc);
1616	tmp = rtc->read(rtc, bcd_reg_info->reg);
1617	ds1685_rtc_end_data_access(rtc);
1618
1619	tmp = ds1685_rtc_bcd2bin(rtc, tmp, bcd_reg_info->mask,
1620				 bin_reg_info->mask);
1621
1622	return sprintf(buf, "%d\n", tmp);
1623}
1624
1625/**
1626 * ds1685_rtc_sysfs_time_regs_store - writes a time/date register via sysfs.
1627 * @dev: pointer to device structure.
1628 * @attr: pointer to device_attribute structure.
1629 * @buf: pointer to char array to hold the output.
1630 * @count: number of bytes written.
1631 */
1632static ssize_t
1633ds1685_rtc_sysfs_time_regs_store(struct device *dev,
1634				 struct device_attribute *attr,
1635				 const char *buf, size_t count)
1636{
1637	long int val = 0;
1638	struct ds1685_priv *rtc = dev_get_drvdata(dev);
1639	const struct ds1685_rtc_time_regs *bcd_reg_info =
1640		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, true);
1641	const struct ds1685_rtc_time_regs *bin_reg_info =
1642		ds1685_rtc_sysfs_time_regs_lookup(attr->attr.name, false);
1643
1644	/* We only accept numbers. */
1645	if (kstrtol(buf, 10, &val) < 0)
1646		return -EINVAL;
1647
1648	/* Make sure we actually matched something. */
1649	if (!bcd_reg_info || !bin_reg_info)
1650		return -EINVAL;
1651
1652	/* Check for a valid range. */
1653	if (rtc->bcd_mode) {
1654		if ((val < bcd_reg_info->min) || (val > bcd_reg_info->max))
1655			return -ERANGE;
1656	} else {
1657		if ((val < bin_reg_info->min) || (val > bin_reg_info->max))
1658			return -ERANGE;
1659	}
1660
1661	val = ds1685_rtc_bin2bcd(rtc, val, bin_reg_info->mask,
1662				 bcd_reg_info->mask);
1663
1664	/* bcd_reg_info->reg == bin_reg_info->reg. */
1665	ds1685_rtc_begin_data_access(rtc);
1666	rtc->write(rtc, bcd_reg_info->reg, val);
1667	ds1685_rtc_end_data_access(rtc);
1668
1669	return count;
1670}
1671
1672/**
1673 * DS1685_RTC_SYSFS_REG_RW - device_attribute for a read-write time register.
1674 * @reg: time/date register to read or write.
1675 */
1676#define DS1685_RTC_SYSFS_TIME_REG_RW(reg)				\
1677	static DEVICE_ATTR(reg, S_IRUGO | S_IWUSR,			\
1678	ds1685_rtc_sysfs_time_regs_show,				\
1679	ds1685_rtc_sysfs_time_regs_store)
1680
1681/*
1682 * Time/Date Register bits.
1683 */
1684DS1685_RTC_SYSFS_TIME_REG_RW(seconds);
1685DS1685_RTC_SYSFS_TIME_REG_RW(minutes);
1686DS1685_RTC_SYSFS_TIME_REG_RW(hours);
1687DS1685_RTC_SYSFS_TIME_REG_RW(wday);
1688DS1685_RTC_SYSFS_TIME_REG_RW(mday);
1689DS1685_RTC_SYSFS_TIME_REG_RW(month);
1690DS1685_RTC_SYSFS_TIME_REG_RW(year);
1691DS1685_RTC_SYSFS_TIME_REG_RW(century);
1692DS1685_RTC_SYSFS_TIME_REG_RW(alarm_seconds);
1693DS1685_RTC_SYSFS_TIME_REG_RW(alarm_minutes);
1694DS1685_RTC_SYSFS_TIME_REG_RW(alarm_hours);
1695DS1685_RTC_SYSFS_TIME_REG_RW(alarm_mday);
1696
1697static struct attribute*
1698ds1685_rtc_sysfs_time_attrs[] = {
1699	&dev_attr_seconds.attr,
1700	&dev_attr_minutes.attr,
1701	&dev_attr_hours.attr,
1702	&dev_attr_wday.attr,
1703	&dev_attr_mday.attr,
1704	&dev_attr_month.attr,
1705	&dev_attr_year.attr,
1706	&dev_attr_century.attr,
1707	NULL,
1708};
1709
1710static const struct attribute_group
1711ds1685_rtc_sysfs_time_grp = {
1712	.name = "datetime",
1713	.attrs = ds1685_rtc_sysfs_time_attrs,
1714};
1715
1716static struct attribute*
1717ds1685_rtc_sysfs_alarm_attrs[] = {
1718	&dev_attr_alarm_seconds.attr,
1719	&dev_attr_alarm_minutes.attr,
1720	&dev_attr_alarm_hours.attr,
1721	&dev_attr_alarm_mday.attr,
1722	NULL,
1723};
1724
1725static const struct attribute_group
1726ds1685_rtc_sysfs_alarm_grp = {
1727	.name = "alarm",
1728	.attrs = ds1685_rtc_sysfs_alarm_attrs,
1729};
1730#endif /* CONFIG_RTC_DS1685_SYSFS_REGS */
1731
1732
1733/**
1734 * ds1685_rtc_sysfs_register - register sysfs files.
1735 * @dev: pointer to device structure.
1736 */
1737static int
1738ds1685_rtc_sysfs_register(struct device *dev)
1739{
1740	int ret = 0;
1741
1742	sysfs_bin_attr_init(&ds1685_rtc_sysfs_nvram_attr);
1743	ret = sysfs_create_bin_file(&dev->kobj, &ds1685_rtc_sysfs_nvram_attr);
1744	if (ret)
1745		return ret;
1746
1747	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_misc_grp);
1748	if (ret)
1749		return ret;
1750
1751#ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1752	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrla_grp);
1753	if (ret)
1754		return ret;
1755
1756	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlb_grp);
1757	if (ret)
1758		return ret;
1759
1760	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlc_grp);
1761	if (ret)
1762		return ret;
1763
1764	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrld_grp);
1765	if (ret)
1766		return ret;
1767
1768	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4a_grp);
1769	if (ret)
1770		return ret;
1771
1772	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4b_grp);
1773	if (ret)
1774		return ret;
1775
1776	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_time_grp);
1777	if (ret)
1778		return ret;
1779
1780	ret = sysfs_create_group(&dev->kobj, &ds1685_rtc_sysfs_alarm_grp);
1781	if (ret)
1782		return ret;
1783#endif
1784	return 0;
1785}
1786
1787/**
1788 * ds1685_rtc_sysfs_unregister - unregister sysfs files.
1789 * @dev: pointer to device structure.
1790 */
1791static int
1792ds1685_rtc_sysfs_unregister(struct device *dev)
1793{
1794	sysfs_remove_bin_file(&dev->kobj, &ds1685_rtc_sysfs_nvram_attr);
1795	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_misc_grp);
1796
1797#ifdef CONFIG_RTC_DS1685_SYSFS_REGS
1798	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrla_grp);
1799	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlb_grp);
1800	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrlc_grp);
1801	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrld_grp);
1802	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4a_grp);
1803	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_ctrl4b_grp);
1804	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_time_grp);
1805	sysfs_remove_group(&dev->kobj, &ds1685_rtc_sysfs_alarm_grp);
1806#endif
1807
1808	return 0;
1809}
1810#endif /* CONFIG_SYSFS */
1811
1812
1813
1814/* ----------------------------------------------------------------------- */
1815/* Driver Probe/Removal */
1816
1817/**
1818 * ds1685_rtc_probe - initializes rtc driver.
1819 * @pdev: pointer to platform_device structure.
1820 */
1821static int
1822ds1685_rtc_probe(struct platform_device *pdev)
1823{
1824	struct rtc_device *rtc_dev;
1825	struct resource *res;
1826	struct ds1685_priv *rtc;
1827	struct ds1685_rtc_platform_data *pdata;
1828	u8 ctrla, ctrlb, hours;
1829	unsigned char am_pm;
1830	int ret = 0;
1831
1832	/* Get the platform data. */
1833	pdata = (struct ds1685_rtc_platform_data *) pdev->dev.platform_data;
1834	if (!pdata)
1835		return -ENODEV;
1836
1837	/* Allocate memory for the rtc device. */
1838	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
1839	if (!rtc)
1840		return -ENOMEM;
1841
1842	/*
1843	 * Allocate/setup any IORESOURCE_MEM resources, if required.  Not all
1844	 * platforms put the RTC in an easy-access place.  Like the SGI Octane,
1845	 * which attaches the RTC to a "ByteBus", hooked to a SuperIO chip
1846	 * that sits behind the IOC3 PCI metadevice.
1847	 */
1848	if (pdata->alloc_io_resources) {
1849		/* Get the platform resources. */
1850		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1851		if (!res)
1852			return -ENXIO;
1853		rtc->size = resource_size(res);
1854
1855		/* Request a memory region. */
1856		/* XXX: mmio-only for now. */
1857		if (!devm_request_mem_region(&pdev->dev, res->start, rtc->size,
1858					     pdev->name))
1859			return -EBUSY;
1860
1861		/*
1862		 * Set the base address for the rtc, and ioremap its
1863		 * registers.
1864		 */
1865		rtc->baseaddr = res->start;
1866		rtc->regs = devm_ioremap(&pdev->dev, res->start, rtc->size);
1867		if (!rtc->regs)
1868			return -ENOMEM;
1869	}
1870	rtc->alloc_io_resources = pdata->alloc_io_resources;
1871
1872	/* Get the register step size. */
1873	if (pdata->regstep > 0)
1874		rtc->regstep = pdata->regstep;
1875	else
1876		rtc->regstep = 1;
1877
1878	/* Platform read function, else default if mmio setup */
1879	if (pdata->plat_read)
1880		rtc->read = pdata->plat_read;
1881	else
1882		if (pdata->alloc_io_resources)
1883			rtc->read = ds1685_read;
1884		else
1885			return -ENXIO;
1886
1887	/* Platform write function, else default if mmio setup */
1888	if (pdata->plat_write)
1889		rtc->write = pdata->plat_write;
1890	else
1891		if (pdata->alloc_io_resources)
1892			rtc->write = ds1685_write;
1893		else
1894			return -ENXIO;
1895
1896	/* Platform pre-shutdown function, if defined. */
1897	if (pdata->plat_prepare_poweroff)
1898		rtc->prepare_poweroff = pdata->plat_prepare_poweroff;
1899
1900	/* Platform wake_alarm function, if defined. */
1901	if (pdata->plat_wake_alarm)
1902		rtc->wake_alarm = pdata->plat_wake_alarm;
1903
1904	/* Platform post_ram_clear function, if defined. */
1905	if (pdata->plat_post_ram_clear)
1906		rtc->post_ram_clear = pdata->plat_post_ram_clear;
1907
1908	/* Init the spinlock, workqueue, & set the driver data. */
1909	spin_lock_init(&rtc->lock);
1910	INIT_WORK(&rtc->work, ds1685_rtc_work_queue);
1911	platform_set_drvdata(pdev, rtc);
1912
1913	/* Turn the oscillator on if is not already on (DV1 = 1). */
1914	ctrla = rtc->read(rtc, RTC_CTRL_A);
1915	if (!(ctrla & RTC_CTRL_A_DV1))
1916		ctrla |= RTC_CTRL_A_DV1;
1917
1918	/* Enable the countdown chain (DV2 = 0) */
1919	ctrla &= ~(RTC_CTRL_A_DV2);
1920
1921	/* Clear RS3-RS0 in Control A. */
1922	ctrla &= ~(RTC_CTRL_A_RS_MASK);
1923
1924	/*
1925	 * All done with Control A.  Switch to Bank 1 for the remainder of
1926	 * the RTC setup so we have access to the extended functions.
1927	 */
1928	ctrla |= RTC_CTRL_A_DV0;
1929	rtc->write(rtc, RTC_CTRL_A, ctrla);
1930
1931	/* Default to 32768kHz output. */
1932	rtc->write(rtc, RTC_EXT_CTRL_4B,
1933		   (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_E32K));
1934
1935	/* Set the SET bit in Control B so we can do some housekeeping. */
1936	rtc->write(rtc, RTC_CTRL_B,
1937		   (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
1938
1939	/* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
1940	while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
1941		cpu_relax();
1942
1943	/*
1944	 * If the platform supports BCD mode, then set DM=0 in Control B.
1945	 * Otherwise, set DM=1 for BIN mode.
1946	 */
1947	ctrlb = rtc->read(rtc, RTC_CTRL_B);
1948	if (pdata->bcd_mode)
1949		ctrlb &= ~(RTC_CTRL_B_DM);
1950	else
1951		ctrlb |= RTC_CTRL_B_DM;
1952	rtc->bcd_mode = pdata->bcd_mode;
1953
1954	/*
1955	 * Disable Daylight Savings Time (DSE = 0).
1956	 * The RTC has hardcoded timezone information that is rendered
1957	 * obselete.  We'll let the OS deal with DST settings instead.
1958	 */
1959	if (ctrlb & RTC_CTRL_B_DSE)
1960		ctrlb &= ~(RTC_CTRL_B_DSE);
1961
1962	/* Force 24-hour mode (2412 = 1). */
1963	if (!(ctrlb & RTC_CTRL_B_2412)) {
1964		/* Reinitialize the time hours. */
1965		hours = rtc->read(rtc, RTC_HRS);
1966		am_pm = hours & RTC_HRS_AMPM_MASK;
1967		hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
1968					   RTC_HRS_12_BIN_MASK);
1969		hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
1970
1971		/* Enable 24-hour mode. */
1972		ctrlb |= RTC_CTRL_B_2412;
1973
1974		/* Write back to Control B, including DM & DSE bits. */
1975		rtc->write(rtc, RTC_CTRL_B, ctrlb);
1976
1977		/* Write the time hours back. */
1978		rtc->write(rtc, RTC_HRS,
1979			   ds1685_rtc_bin2bcd(rtc, hours,
1980					      RTC_HRS_24_BIN_MASK,
1981					      RTC_HRS_24_BCD_MASK));
1982
1983		/* Reinitialize the alarm hours. */
1984		hours = rtc->read(rtc, RTC_HRS_ALARM);
1985		am_pm = hours & RTC_HRS_AMPM_MASK;
1986		hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
1987					   RTC_HRS_12_BIN_MASK);
1988		hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
1989
1990		/* Write the alarm hours back. */
1991		rtc->write(rtc, RTC_HRS_ALARM,
1992			   ds1685_rtc_bin2bcd(rtc, hours,
1993					      RTC_HRS_24_BIN_MASK,
1994					      RTC_HRS_24_BCD_MASK));
1995	} else {
1996		/* 24-hour mode is already set, so write Control B back. */
1997		rtc->write(rtc, RTC_CTRL_B, ctrlb);
1998	}
1999
2000	/* Unset the SET bit in Control B so the RTC can update. */
2001	rtc->write(rtc, RTC_CTRL_B,
2002		   (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
2003
2004	/* Check the main battery. */
2005	if (!(rtc->read(rtc, RTC_CTRL_D) & RTC_CTRL_D_VRT))
2006		dev_warn(&pdev->dev,
2007			 "Main battery is exhausted! RTC may be invalid!\n");
2008
2009	/* Check the auxillary battery.  It is optional. */
2010	if (!(rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_VRT2))
2011		dev_warn(&pdev->dev,
2012			 "Aux battery is exhausted or not available.\n");
2013
2014	/* Read Ctrl B and clear PIE/AIE/UIE. */
2015	rtc->write(rtc, RTC_CTRL_B,
2016		   (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_PAU_MASK)));
2017
2018	/* Reading Ctrl C auto-clears PF/AF/UF. */
2019	rtc->read(rtc, RTC_CTRL_C);
2020
2021	/* Read Ctrl 4B and clear RIE/WIE/KSE. */
2022	rtc->write(rtc, RTC_EXT_CTRL_4B,
2023		   (rtc->read(rtc, RTC_EXT_CTRL_4B) & ~(RTC_CTRL_4B_RWK_MASK)));
2024
2025	/* Clear RF/WF/KF in Ctrl 4A. */
2026	rtc->write(rtc, RTC_EXT_CTRL_4A,
2027		   (rtc->read(rtc, RTC_EXT_CTRL_4A) & ~(RTC_CTRL_4A_RWK_MASK)));
2028
2029	/*
2030	 * Re-enable KSE to handle power button events.  We do not enable
2031	 * WIE or RIE by default.
2032	 */
2033	rtc->write(rtc, RTC_EXT_CTRL_4B,
2034		   (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_KSE));
2035
2036	/*
2037	 * Fetch the IRQ and setup the interrupt handler.
2038	 *
2039	 * Not all platforms have the IRQF pin tied to something.  If not, the
2040	 * RTC will still set the *IE / *F flags and raise IRQF in ctrlc, but
2041	 * there won't be an automatic way of notifying the kernel about it,
2042	 * unless ctrlc is explicitly polled.
2043	 */
2044	if (!pdata->no_irq) {
2045		ret = platform_get_irq(pdev, 0);
2046		if (ret > 0) {
2047			rtc->irq_num = ret;
2048
2049			/* Request an IRQ. */
2050			ret = devm_request_irq(&pdev->dev, rtc->irq_num,
2051					       ds1685_rtc_irq_handler,
2052					       IRQF_SHARED, pdev->name, pdev);
2053
2054			/* Check to see if something came back. */
2055			if (unlikely(ret)) {
2056				dev_warn(&pdev->dev,
2057					 "RTC interrupt not available\n");
2058				rtc->irq_num = 0;
2059			}
2060		} else
2061			return ret;
2062	}
2063	rtc->no_irq = pdata->no_irq;
2064
2065	/* Setup complete. */
2066	ds1685_rtc_switch_to_bank0(rtc);
2067
2068	/* Register the device as an RTC. */
2069	rtc_dev = rtc_device_register(pdev->name, &pdev->dev,
2070				      &ds1685_rtc_ops, THIS_MODULE);
2071
2072	/* Success? */
2073	if (IS_ERR(rtc_dev))
2074		return PTR_ERR(rtc_dev);
2075
2076	/* Maximum periodic rate is 8192Hz (0.122070ms). */
2077	rtc_dev->max_user_freq = RTC_MAX_USER_FREQ;
2078
2079	/* See if the platform doesn't support UIE. */
2080	if (pdata->uie_unsupported)
2081		rtc_dev->uie_unsupported = 1;
2082	rtc->uie_unsupported = pdata->uie_unsupported;
2083
2084	rtc->dev = rtc_dev;
2085
2086#ifdef CONFIG_SYSFS
2087	ret = ds1685_rtc_sysfs_register(&pdev->dev);
2088	if (ret)
2089		rtc_device_unregister(rtc->dev);
2090#endif
2091
2092	/* Done! */
2093	return ret;
2094}
2095
2096/**
2097 * ds1685_rtc_remove - removes rtc driver.
2098 * @pdev: pointer to platform_device structure.
2099 */
2100static int
2101ds1685_rtc_remove(struct platform_device *pdev)
2102{
2103	struct ds1685_priv *rtc = platform_get_drvdata(pdev);
2104
2105#ifdef CONFIG_SYSFS
2106	ds1685_rtc_sysfs_unregister(&pdev->dev);
2107#endif
2108
2109	rtc_device_unregister(rtc->dev);
2110
2111	/* Read Ctrl B and clear PIE/AIE/UIE. */
2112	rtc->write(rtc, RTC_CTRL_B,
2113		   (rtc->read(rtc, RTC_CTRL_B) &
2114		    ~(RTC_CTRL_B_PAU_MASK)));
2115
2116	/* Reading Ctrl C auto-clears PF/AF/UF. */
2117	rtc->read(rtc, RTC_CTRL_C);
2118
2119	/* Read Ctrl 4B and clear RIE/WIE/KSE. */
2120	rtc->write(rtc, RTC_EXT_CTRL_4B,
2121		   (rtc->read(rtc, RTC_EXT_CTRL_4B) &
2122		    ~(RTC_CTRL_4B_RWK_MASK)));
2123
2124	/* Manually clear RF/WF/KF in Ctrl 4A. */
2125	rtc->write(rtc, RTC_EXT_CTRL_4A,
2126		   (rtc->read(rtc, RTC_EXT_CTRL_4A) &
2127		    ~(RTC_CTRL_4A_RWK_MASK)));
2128
2129	cancel_work_sync(&rtc->work);
2130
2131	return 0;
2132}
2133
2134/**
2135 * ds1685_rtc_driver - rtc driver properties.
2136 */
2137static struct platform_driver ds1685_rtc_driver = {
2138	.driver		= {
2139		.name	= "rtc-ds1685",
2140	},
2141	.probe		= ds1685_rtc_probe,
2142	.remove		= ds1685_rtc_remove,
2143};
2144module_platform_driver(ds1685_rtc_driver);
2145/* ----------------------------------------------------------------------- */
2146
2147
2148/* ----------------------------------------------------------------------- */
2149/* Poweroff function */
2150
2151/**
2152 * ds1685_rtc_poweroff - uses the RTC chip to power the system off.
2153 * @pdev: pointer to platform_device structure.
2154 */
2155void __noreturn
2156ds1685_rtc_poweroff(struct platform_device *pdev)
2157{
2158	u8 ctrla, ctrl4a, ctrl4b;
2159	struct ds1685_priv *rtc;
2160
2161	/* Check for valid RTC data, else, spin forever. */
2162	if (unlikely(!pdev)) {
2163		pr_emerg("platform device data not available, spinning forever ...\n");
2164		while(1);
2165		unreachable();
2166	} else {
2167		/* Get the rtc data. */
2168		rtc = platform_get_drvdata(pdev);
2169
2170		/*
2171		 * Disable our IRQ.  We're powering down, so we're not
2172		 * going to worry about cleaning up.  Most of that should
2173		 * have been taken care of by the shutdown scripts and this
2174		 * is the final function call.
2175		 */
2176		if (!rtc->no_irq)
2177			disable_irq_nosync(rtc->irq_num);
2178
2179		/* Oscillator must be on and the countdown chain enabled. */
2180		ctrla = rtc->read(rtc, RTC_CTRL_A);
2181		ctrla |= RTC_CTRL_A_DV1;
2182		ctrla &= ~(RTC_CTRL_A_DV2);
2183		rtc->write(rtc, RTC_CTRL_A, ctrla);
2184
2185		/*
2186		 * Read Control 4A and check the status of the auxillary
2187		 * battery.  This must be present and working (VRT2 = 1)
2188		 * for wakeup and kickstart functionality to be useful.
2189		 */
2190		ds1685_rtc_switch_to_bank1(rtc);
2191		ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
2192		if (ctrl4a & RTC_CTRL_4A_VRT2) {
2193			/* Clear all of the interrupt flags on Control 4A. */
2194			ctrl4a &= ~(RTC_CTRL_4A_RWK_MASK);
2195			rtc->write(rtc, RTC_EXT_CTRL_4A, ctrl4a);
2196
2197			/*
2198			 * The auxillary battery is present and working.
2199			 * Enable extended functions (ABE=1), enable
2200			 * wake-up (WIE=1), and enable kickstart (KSE=1)
2201			 * in Control 4B.
2202			 */
2203			ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
2204			ctrl4b |= (RTC_CTRL_4B_ABE | RTC_CTRL_4B_WIE |
2205				   RTC_CTRL_4B_KSE);
2206			rtc->write(rtc, RTC_EXT_CTRL_4B, ctrl4b);
2207		}
2208
2209		/* Set PAB to 1 in Control 4A to power the system down. */
2210		dev_warn(&pdev->dev, "Powerdown.\n");
2211		msleep(20);
2212		rtc->write(rtc, RTC_EXT_CTRL_4A,
2213			   (ctrl4a | RTC_CTRL_4A_PAB));
2214
2215		/* Spin ... we do not switch back to bank0. */
 
2216		unreachable();
2217	}
2218}
2219EXPORT_SYMBOL(ds1685_rtc_poweroff);
2220/* ----------------------------------------------------------------------- */
2221
2222
2223MODULE_AUTHOR("Joshua Kinard <kumba@gentoo.org>");
2224MODULE_AUTHOR("Matthias Fuchs <matthias.fuchs@esd-electronics.com>");
2225MODULE_DESCRIPTION("Dallas/Maxim DS1685/DS1687-series RTC driver");
2226MODULE_LICENSE("GPL");
2227MODULE_VERSION(DRV_VERSION);
2228MODULE_ALIAS("platform:rtc-ds1685");