drivers/rtc/rtc-ds1685.c

   1 /*
   2  * An rtc driver for the Dallas/Maxim DS1685/DS1687 and related real-time
   3  * chips.
   4  *
   5  * Copyright (C) 2011-2014 Joshua Kinard <kumba@gentoo.org>.
   6  * Copyright (C) 2009 Matthias Fuchs <matthias.fuchs@esd-electronics.com>.
   7  *
   8  * References:
   9  *    DS1685/DS1687 3V/5V Real-Time Clocks, 19-5215, Rev 4/10.
  10  *    DS17x85/DS17x87 3V/5V Real-Time Clocks, 19-5222, Rev 4/10.
  11  *    DS1689/DS1693 3V/5V Serialized Real-Time Clocks, Rev 112105.
  12  *    Application Note 90, Using the Multiplex Bus RTC Extended Features.
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License version 2 as
  16  * published by the Free Software Foundation.
  17  */
  18
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/bcd.h>
  22 #include <linux/delay.h>
  23 #include <linux/io.h>
  24 #include <linux/module.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/rtc.h>
  27 #include <linux/workqueue.h>
  28
  29 #include <linux/rtc/ds1685.h>
  30
  31 #ifdef CONFIG_PROC_FS
  32 #include <linux/proc_fs.h>
  33 #endif
  34
  35
  36 /* ----------------------------------------------------------------------- */
  37 /* Standard read/write functions if platform does not provide overrides */
  38
  39 /**
  40  * ds1685_read - read a value from an rtc register.
  41  * @rtc: pointer to the ds1685 rtc structure.
  42  * @reg: the register address to read.
  43  */
  44 static u8
  45 ds1685_read(struct ds1685_priv *rtc, int reg)
  46 {
  47         return readb((u8 __iomem *)rtc->regs +
  48                      (reg * rtc->regstep));
  49 }
  50
  51 /**
  52  * ds1685_write - write a value to an rtc register.
  53  * @rtc: pointer to the ds1685 rtc structure.
  54  * @reg: the register address to write.
  55  * @value: value to write to the register.
  56  */
  57 static void
  58 ds1685_write(struct ds1685_priv *rtc, int reg, u8 value)
  59 {
  60         writeb(value, ((u8 __iomem *)rtc->regs +
  61                        (reg * rtc->regstep)));
  62 }
  63 /* ----------------------------------------------------------------------- */
  64
  65
  66 /* ----------------------------------------------------------------------- */
  67 /* Inlined functions */
  68
  69 /**
  70  * ds1685_rtc_bcd2bin - bcd2bin wrapper in case platform doesn't support BCD.
  71  * @rtc: pointer to the ds1685 rtc structure.
  72  * @val: u8 time value to consider converting.
  73  * @bcd_mask: u8 mask value if BCD mode is used.
  74  * @bin_mask: u8 mask value if BIN mode is used.
  75  *
  76  * Returns the value, converted to BIN if originally in BCD and bcd_mode TRUE.
  77  */
  78 static inline u8
  79 ds1685_rtc_bcd2bin(struct ds1685_priv *rtc, u8 val, u8 bcd_mask, u8 bin_mask)
  80 {
  81         if (rtc->bcd_mode)
  82                 return (bcd2bin(val) & bcd_mask);
  83
  84         return (val & bin_mask);
  85 }
  86
  87 /**
  88  * ds1685_rtc_bin2bcd - bin2bcd wrapper in case platform doesn't support BCD.
  89  * @rtc: pointer to the ds1685 rtc structure.
  90  * @val: u8 time value to consider converting.
  91  * @bin_mask: u8 mask value if BIN mode is used.
  92  * @bcd_mask: u8 mask value if BCD mode is used.
  93  *
  94  * Returns the value, converted to BCD if originally in BIN and bcd_mode TRUE.
  95  */
  96 static inline u8
  97 ds1685_rtc_bin2bcd(struct ds1685_priv *rtc, u8 val, u8 bin_mask, u8 bcd_mask)
  98 {
  99         if (rtc->bcd_mode)
 100                 return (bin2bcd(val) & bcd_mask);
 101
 102         return (val & bin_mask);
 103 }
 104
 105 /**
 106  * s1685_rtc_check_mday - check validity of the day of month.
 107  * @rtc: pointer to the ds1685 rtc structure.
 108  * @mday: day of month.
 109  *
 110  * Returns -EDOM if the day of month is not within 1..31 range.
 111  */
 112 static inline int
 113 ds1685_rtc_check_mday(struct ds1685_priv *rtc, u8 mday)
 114 {
 115         if (rtc->bcd_mode) {
 116                 if (mday < 0x01 || mday > 0x31 || (mday & 0x0f) > 0x09)
 117                         return -EDOM;
 118         } else {
 119                 if (mday < 1 || mday > 31)
 120                         return -EDOM;
 121         }
 122         return 0;
 123 }
 124
 125 /**
 126  * ds1685_rtc_switch_to_bank0 - switch the rtc to bank 0.
 127  * @rtc: pointer to the ds1685 rtc structure.
 128  */
 129 static inline void
 130 ds1685_rtc_switch_to_bank0(struct ds1685_priv *rtc)
 131 {
 132         rtc->write(rtc, RTC_CTRL_A,
 133                    (rtc->read(rtc, RTC_CTRL_A) & ~(RTC_CTRL_A_DV0)));
 134 }
 135
 136 /**
 137  * ds1685_rtc_switch_to_bank1 - switch the rtc to bank 1.
 138  * @rtc: pointer to the ds1685 rtc structure.
 139  */
 140 static inline void
 141 ds1685_rtc_switch_to_bank1(struct ds1685_priv *rtc)
 142 {
 143         rtc->write(rtc, RTC_CTRL_A,
 144                    (rtc->read(rtc, RTC_CTRL_A) | RTC_CTRL_A_DV0));
 145 }
 146
 147 /**
 148  * ds1685_rtc_begin_data_access - prepare the rtc for data access.
 149  * @rtc: pointer to the ds1685 rtc structure.
 150  *
 151  * This takes several steps to prepare the rtc for access to get/set time
 152  * and alarm values from the rtc registers:
 153  *  - Sets the SET bit in Control Register B.
 154  *  - Reads Ext Control Register 4A and checks the INCR bit.
 155  *  - If INCR is active, a short delay is added before Ext Control Register 4A
 156  *    is read again in a loop until INCR is inactive.
 157  *  - Switches the rtc to bank 1.  This allows access to all relevant
 158  *    data for normal rtc operation, as bank 0 contains only the nvram.
 159  */
 160 static inline void
 161 ds1685_rtc_begin_data_access(struct ds1685_priv *rtc)
 162 {
 163         /* Set the SET bit in Ctrl B */
 164         rtc->write(rtc, RTC_CTRL_B,
 165                    (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
 166
 167         /* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
 168         while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
 169                 cpu_relax();
 170
 171         /* Switch to Bank 1 */
 172         ds1685_rtc_switch_to_bank1(rtc);
 173 }
 174
 175 /**
 176  * ds1685_rtc_end_data_access - end data access on the rtc.
 177  * @rtc: pointer to the ds1685 rtc structure.
 178  *
 179  * This ends what was started by ds1685_rtc_begin_data_access:
 180  *  - Switches the rtc back to bank 0.
 181  *  - Clears the SET bit in Control Register B.
 182  */
 183 static inline void
 184 ds1685_rtc_end_data_access(struct ds1685_priv *rtc)
 185 {
 186         /* Switch back to Bank 0 */
 187         ds1685_rtc_switch_to_bank1(rtc);
 188
 189         /* Clear the SET bit in Ctrl B */
 190         rtc->write(rtc, RTC_CTRL_B,
 191                    (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
 192 }
 193
 194 /**
 195  * ds1685_rtc_get_ssn - retrieve the silicon serial number.
 196  * @rtc: pointer to the ds1685 rtc structure.
 197  * @ssn: u8 array to hold the bits of the silicon serial number.
 198  *
 199  * This number starts at 0x40, and is 8-bytes long, ending at 0x47. The
 200  * first byte is the model number, the next six bytes are the serial number
 201  * digits, and the final byte is a CRC check byte.  Together, they form the
 202  * silicon serial number.
 203  *
 204  * These values are stored in bank1, so ds1685_rtc_switch_to_bank1 must be
 205  * called first before calling this function, else data will be read out of
 206  * the bank0 NVRAM.  Be sure to call ds1685_rtc_switch_to_bank0 when done.
 207  */
 208 static inline void
 209 ds1685_rtc_get_ssn(struct ds1685_priv *rtc, u8 *ssn)
 210 {
 211         ssn[0] = rtc->read(rtc, RTC_BANK1_SSN_MODEL);
 212         ssn[1] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_1);
 213         ssn[2] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_2);
 214         ssn[3] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_3);
 215         ssn[4] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_4);
 216         ssn[5] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_5);
 217         ssn[6] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_6);
 218         ssn[7] = rtc->read(rtc, RTC_BANK1_SSN_CRC);
 219 }
 220 /* ----------------------------------------------------------------------- */
 221
 222
 223 /* ----------------------------------------------------------------------- */
 224 /* Read/Set Time & Alarm functions */
 225
 226 /**
 227  * ds1685_rtc_read_time - reads the time registers.
 228  * @dev: pointer to device structure.
 229  * @tm: pointer to rtc_time structure.
 230  */
 231 static int
 232 ds1685_rtc_read_time(struct device *dev, struct rtc_time *tm)
 233 {
 234         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 235         u8 ctrlb, century;
 236         u8 seconds, minutes, hours, wday, mday, month, years;
 237
 238         /* Fetch the time info from the RTC registers. */
 239         ds1685_rtc_begin_data_access(rtc);
 240         seconds = rtc->read(rtc, RTC_SECS);
 241         minutes = rtc->read(rtc, RTC_MINS);
 242         hours   = rtc->read(rtc, RTC_HRS);
 243         wday    = rtc->read(rtc, RTC_WDAY);
 244         mday    = rtc->read(rtc, RTC_MDAY);
 245         month   = rtc->read(rtc, RTC_MONTH);
 246         years   = rtc->read(rtc, RTC_YEAR);
 247         century = rtc->read(rtc, RTC_CENTURY);
 248         ctrlb   = rtc->read(rtc, RTC_CTRL_B);
 249         ds1685_rtc_end_data_access(rtc);
 250
 251         /* bcd2bin if needed, perform fixups, and store to rtc_time. */
 252         years        = ds1685_rtc_bcd2bin(rtc, years, RTC_YEAR_BCD_MASK,
 253                                           RTC_YEAR_BIN_MASK);
 254         century      = ds1685_rtc_bcd2bin(rtc, century, RTC_CENTURY_MASK,
 255                                           RTC_CENTURY_MASK);
 256         tm->tm_sec   = ds1685_rtc_bcd2bin(rtc, seconds, RTC_SECS_BCD_MASK,
 257                                           RTC_SECS_BIN_MASK);
 258         tm->tm_min   = ds1685_rtc_bcd2bin(rtc, minutes, RTC_MINS_BCD_MASK,
 259                                           RTC_MINS_BIN_MASK);
 260         tm->tm_hour  = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_24_BCD_MASK,
 261                                           RTC_HRS_24_BIN_MASK);
 262         tm->tm_wday  = (ds1685_rtc_bcd2bin(rtc, wday, RTC_WDAY_MASK,
 263                                            RTC_WDAY_MASK) - 1);
 264         tm->tm_mday  = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
 265                                           RTC_MDAY_BIN_MASK);
 266         tm->tm_mon   = (ds1685_rtc_bcd2bin(rtc, month, RTC_MONTH_BCD_MASK,
 267                                            RTC_MONTH_BIN_MASK) - 1);
 268         tm->tm_year  = ((years + (century * 100)) - 1900);
 269         tm->tm_yday  = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 270         tm->tm_isdst = 0; /* RTC has hardcoded timezone, so don't use. */
 271
 272         return 0;
 273 }
 274
 275 /**
 276  * ds1685_rtc_set_time - sets the time registers.
 277  * @dev: pointer to device structure.
 278  * @tm: pointer to rtc_time structure.
 279  */
 280 static int
 281 ds1685_rtc_set_time(struct device *dev, struct rtc_time *tm)
 282 {
 283         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 284         u8 ctrlb, seconds, minutes, hours, wday, mday, month, years, century;
 285
 286         /* Fetch the time info from rtc_time. */
 287         seconds = ds1685_rtc_bin2bcd(rtc, tm->tm_sec, RTC_SECS_BIN_MASK,
 288                                      RTC_SECS_BCD_MASK);
 289         minutes = ds1685_rtc_bin2bcd(rtc, tm->tm_min, RTC_MINS_BIN_MASK,
 290                                      RTC_MINS_BCD_MASK);
 291         hours   = ds1685_rtc_bin2bcd(rtc, tm->tm_hour, RTC_HRS_24_BIN_MASK,
 292                                      RTC_HRS_24_BCD_MASK);
 293         wday    = ds1685_rtc_bin2bcd(rtc, (tm->tm_wday + 1), RTC_WDAY_MASK,
 294                                      RTC_WDAY_MASK);
 295         mday    = ds1685_rtc_bin2bcd(rtc, tm->tm_mday, RTC_MDAY_BIN_MASK,
 296                                      RTC_MDAY_BCD_MASK);
 297         month   = ds1685_rtc_bin2bcd(rtc, (tm->tm_mon + 1), RTC_MONTH_BIN_MASK,
 298                                      RTC_MONTH_BCD_MASK);
 299         years   = ds1685_rtc_bin2bcd(rtc, (tm->tm_year % 100),
 300                                      RTC_YEAR_BIN_MASK, RTC_YEAR_BCD_MASK);
 301         century = ds1685_rtc_bin2bcd(rtc, ((tm->tm_year + 1900) / 100),
 302                                      RTC_CENTURY_MASK, RTC_CENTURY_MASK);
 303
 304         /*
 305          * Perform Sanity Checks:
 306          *   - Months: !> 12, Month Day != 0.
 307          *   - Month Day !> Max days in current month.
 308          *   - Hours !>= 24, Mins !>= 60, Secs !>= 60, & Weekday !> 7.
 309          */
 310         if ((tm->tm_mon > 11) || (mday == 0))
 311                 return -EDOM;
 312
 313         if (tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year))
 314                 return -EDOM;
 315
 316         if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) ||
 317             (tm->tm_sec >= 60)  || (wday > 7))
 318                 return -EDOM;
 319
 320         /*
 321          * Set the data mode to use and store the time values in the
 322          * RTC registers.
 323          */
 324         ds1685_rtc_begin_data_access(rtc);
 325         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 326         if (rtc->bcd_mode)
 327                 ctrlb &= ~(RTC_CTRL_B_DM);
 328         else
 329                 ctrlb |= RTC_CTRL_B_DM;
 330         rtc->write(rtc, RTC_CTRL_B, ctrlb);
 331         rtc->write(rtc, RTC_SECS, seconds);
 332         rtc->write(rtc, RTC_MINS, minutes);
 333         rtc->write(rtc, RTC_HRS, hours);
 334         rtc->write(rtc, RTC_WDAY, wday);
 335         rtc->write(rtc, RTC_MDAY, mday);
 336         rtc->write(rtc, RTC_MONTH, month);
 337         rtc->write(rtc, RTC_YEAR, years);
 338         rtc->write(rtc, RTC_CENTURY, century);
 339         ds1685_rtc_end_data_access(rtc);
 340
 341         return 0;
 342 }
 343
 344 /**
 345  * ds1685_rtc_read_alarm - reads the alarm registers.
 346  * @dev: pointer to device structure.
 347  * @alrm: pointer to rtc_wkalrm structure.
 348  *
 349  * There are three primary alarm registers: seconds, minutes, and hours.
 350  * A fourth alarm register for the month date is also available in bank1 for
 351  * kickstart/wakeup features.  The DS1685/DS1687 manual states that a
 352  * "don't care" value ranging from 0xc0 to 0xff may be written into one or
 353  * more of the three alarm bytes to act as a wildcard value.  The fourth
 354  * byte doesn't support a "don't care" value.
 355  */
 356 static int
 357 ds1685_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 358 {
 359         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 360         u8 seconds, minutes, hours, mday, ctrlb, ctrlc;
 361         int ret;
 362
 363         /* Fetch the alarm info from the RTC alarm registers. */
 364         ds1685_rtc_begin_data_access(rtc);
 365         seconds = rtc->read(rtc, RTC_SECS_ALARM);
 366         minutes = rtc->read(rtc, RTC_MINS_ALARM);
 367         hours   = rtc->read(rtc, RTC_HRS_ALARM);
 368         mday    = rtc->read(rtc, RTC_MDAY_ALARM);
 369         ctrlb   = rtc->read(rtc, RTC_CTRL_B);
 370         ctrlc   = rtc->read(rtc, RTC_CTRL_C);
 371         ds1685_rtc_end_data_access(rtc);
 372
 373         /* Check the month date for validity. */
 374         ret = ds1685_rtc_check_mday(rtc, mday);
 375         if (ret)
 376                 return ret;
 377
 378         /*
 379          * Check the three alarm bytes.
 380          *
 381          * The Linux RTC system doesn't support the "don't care" capability
 382          * of this RTC chip.  We check for it anyways in case support is
 383          * added in the future and only assign when we care.
 384          */
 385         if (likely(seconds < 0xc0))
 386                 alrm->time.tm_sec = ds1685_rtc_bcd2bin(rtc, seconds,
 387                                                        RTC_SECS_BCD_MASK,
 388                                                        RTC_SECS_BIN_MASK);
 389
 390         if (likely(minutes < 0xc0))
 391                 alrm->time.tm_min = ds1685_rtc_bcd2bin(rtc, minutes,
 392                                                        RTC_MINS_BCD_MASK,
 393                                                        RTC_MINS_BIN_MASK);
 394
 395         if (likely(hours < 0xc0))
 396                 alrm->time.tm_hour = ds1685_rtc_bcd2bin(rtc, hours,
 397                                                         RTC_HRS_24_BCD_MASK,
 398                                                         RTC_HRS_24_BIN_MASK);
 399
 400         /* Write the data to rtc_wkalrm. */
 401         alrm->time.tm_mday = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
 402                                                 RTC_MDAY_BIN_MASK);
 403         alrm->enabled = !!(ctrlb & RTC_CTRL_B_AIE);
 404         alrm->pending = !!(ctrlc & RTC_CTRL_C_AF);
 405
 406         return 0;
 407 }
 408
 409 /**
 410  * ds1685_rtc_set_alarm - sets the alarm in registers.
 411  * @dev: pointer to device structure.
 412  * @alrm: pointer to rtc_wkalrm structure.
 413  */
 414 static int
 415 ds1685_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 416 {
 417         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 418         u8 ctrlb, seconds, minutes, hours, mday;
 419         int ret;
 420
 421         /* Fetch the alarm info and convert to BCD. */
 422         seconds = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_sec,
 423                                      RTC_SECS_BIN_MASK,
 424                                      RTC_SECS_BCD_MASK);
 425         minutes = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_min,
 426                                      RTC_MINS_BIN_MASK,
 427                                      RTC_MINS_BCD_MASK);
 428         hours   = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_hour,
 429                                      RTC_HRS_24_BIN_MASK,
 430                                      RTC_HRS_24_BCD_MASK);
 431         mday    = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_mday,
 432                                      RTC_MDAY_BIN_MASK,
 433                                      RTC_MDAY_BCD_MASK);
 434
 435         /* Check the month date for validity. */
 436         ret = ds1685_rtc_check_mday(rtc, mday);
 437         if (ret)
 438                 return ret;
 439
 440         /*
 441          * Check the three alarm bytes.
 442          *
 443          * The Linux RTC system doesn't support the "don't care" capability
 444          * of this RTC chip because rtc_valid_tm tries to validate every
 445          * field, and we only support four fields.  We put the support
 446          * here anyways for the future.
 447          */
 448         if (unlikely(seconds >= 0xc0))
 449                 seconds = 0xff;
 450
 451         if (unlikely(minutes >= 0xc0))
 452                 minutes = 0xff;
 453
 454         if (unlikely(hours >= 0xc0))
 455                 hours = 0xff;
 456
 457         alrm->time.tm_mon       = -1;
 458         alrm->time.tm_year      = -1;
 459         alrm->time.tm_wday      = -1;
 460         alrm->time.tm_yday      = -1;
 461         alrm->time.tm_isdst     = -1;
 462
 463         /* Disable the alarm interrupt first. */
 464         ds1685_rtc_begin_data_access(rtc);
 465         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 466         rtc->write(rtc, RTC_CTRL_B, (ctrlb & ~(RTC_CTRL_B_AIE)));
 467
 468         /* Read ctrlc to clear RTC_CTRL_C_AF. */
 469         rtc->read(rtc, RTC_CTRL_C);
 470
 471         /*
 472          * Set the data mode to use and store the time values in the
 473          * RTC registers.
 474          */
 475         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 476         if (rtc->bcd_mode)
 477                 ctrlb &= ~(RTC_CTRL_B_DM);
 478         else
 479                 ctrlb |= RTC_CTRL_B_DM;
 480         rtc->write(rtc, RTC_CTRL_B, ctrlb);
 481         rtc->write(rtc, RTC_SECS_ALARM, seconds);
 482         rtc->write(rtc, RTC_MINS_ALARM, minutes);
 483         rtc->write(rtc, RTC_HRS_ALARM, hours);
 484         rtc->write(rtc, RTC_MDAY_ALARM, mday);
 485
 486         /* Re-enable the alarm if needed. */
 487         if (alrm->enabled) {
 488                 ctrlb = rtc->read(rtc, RTC_CTRL_B);
 489                 ctrlb |= RTC_CTRL_B_AIE;
 490                 rtc->write(rtc, RTC_CTRL_B, ctrlb);
 491         }
 492
 493         /* Done! */
 494         ds1685_rtc_end_data_access(rtc);
 495
 496         return 0;
 497 }
 498 /* ----------------------------------------------------------------------- */
 499
 500
 501 /* ----------------------------------------------------------------------- */
 502 /* /dev/rtcX Interface functions */
 503
 504 /**
 505  * ds1685_rtc_alarm_irq_enable - replaces ioctl() RTC_AIE on/off.
 506  * @dev: pointer to device structure.
 507  * @enabled: flag indicating whether to enable or disable.
 508  */
 509 static int
 510 ds1685_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 511 {
 512         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 513
 514         /* Flip the requisite interrupt-enable bit. */
 515         if (enabled)
 516                 rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) |
 517                                              RTC_CTRL_B_AIE));
 518         else
 519                 rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) &
 520                                              ~(RTC_CTRL_B_AIE)));
 521
 522         /* Read Control C to clear all the flag bits. */
 523         rtc->read(rtc, RTC_CTRL_C);
 524
 525         return 0;
 526 }
 527 /* ----------------------------------------------------------------------- */
 528
 529
 530 /* ----------------------------------------------------------------------- */
 531 /* IRQ handler */
 532
 533 /**
 534  * ds1685_rtc_extended_irq - take care of extended interrupts
 535  * @rtc: pointer to the ds1685 rtc structure.
 536  * @pdev: platform device pointer.
 537  */
 538 static void
 539 ds1685_rtc_extended_irq(struct ds1685_priv *rtc, struct platform_device *pdev)
 540 {
 541         u8 ctrl4a, ctrl4b;
 542
 543         ds1685_rtc_switch_to_bank1(rtc);
 544         ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
 545         ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
 546
 547         /*
 548          * Check for a kickstart interrupt. With Vcc applied, this
 549          * typically means that the power button was pressed, so we
 550          * begin the shutdown sequence.
 551          */
 552         if ((ctrl4b & RTC_CTRL_4B_KSE) && (ctrl4a & RTC_CTRL_4A_KF)) {
 553                 /* Briefly disable kickstarts to debounce button presses. */
 554                 rtc->write(rtc, RTC_EXT_CTRL_4B,
 555                            (rtc->read(rtc, RTC_EXT_CTRL_4B) &
 556                             ~(RTC_CTRL_4B_KSE)));
 557
 558                 /* Clear the kickstart flag. */
 559                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 560                            (ctrl4a & ~(RTC_CTRL_4A_KF)));
 561
 562
 563                 /*
 564                  * Sleep 500ms before re-enabling kickstarts.  This allows
 565                  * adequate time to avoid reading signal jitter as additional
 566                  * button presses.
 567                  */
 568                 msleep(500);
 569                 rtc->write(rtc, RTC_EXT_CTRL_4B,
 570                            (rtc->read(rtc, RTC_EXT_CTRL_4B) |
 571                             RTC_CTRL_4B_KSE));
 572
 573                 /* Call the platform pre-poweroff function. Else, shutdown. */
 574                 if (rtc->prepare_poweroff != NULL)
 575                         rtc->prepare_poweroff();
 576                 else
 577                         ds1685_rtc_poweroff(pdev);
 578         }
 579
 580         /*
 581          * Check for a wake-up interrupt.  With Vcc applied, this is
 582          * essentially a second alarm interrupt, except it takes into
 583          * account the 'date' register in bank1 in addition to the
 584          * standard three alarm registers.
 585          */
 586         if ((ctrl4b & RTC_CTRL_4B_WIE) && (ctrl4a & RTC_CTRL_4A_WF)) {
 587                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 588                            (ctrl4a & ~(RTC_CTRL_4A_WF)));
 589
 590                 /* Call the platform wake_alarm function if defined. */
 591                 if (rtc->wake_alarm != NULL)
 592                         rtc->wake_alarm();
 593                 else
 594                         dev_warn(&pdev->dev,
 595                                  "Wake Alarm IRQ just occurred!\n");
 596         }
 597
 598         /*
 599          * Check for a ram-clear interrupt.  This happens if RIE=1 and RF=0
 600          * when RCE=1 in 4B.  This clears all NVRAM bytes in bank0 by setting
 601          * each byte to a logic 1.  This has no effect on any extended
 602          * NV-SRAM that might be present, nor on the time/calendar/alarm
 603          * registers.  After a ram-clear is completed, there is a minimum
 604          * recovery time of ~150ms in which all reads/writes are locked out.
 605          * NOTE: A ram-clear can still occur if RCE=1 and RIE=0.  We cannot
 606          * catch this scenario.
 607          */
 608         if ((ctrl4b & RTC_CTRL_4B_RIE) && (ctrl4a & RTC_CTRL_4A_RF)) {
 609                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 610                            (ctrl4a & ~(RTC_CTRL_4A_RF)));
 611                 msleep(150);
 612
 613                 /* Call the platform post_ram_clear function if defined. */
 614                 if (rtc->post_ram_clear != NULL)
 615                         rtc->post_ram_clear();
 616                 else
 617                         dev_warn(&pdev->dev,
 618                                  "RAM-Clear IRQ just occurred!\n");
 619         }
 620         ds1685_rtc_switch_to_bank0(rtc);
 621 }
 622
 623 /**
 624  * ds1685_rtc_irq_handler - IRQ handler.
 625  * @irq: IRQ number.
 626  * @dev_id: platform device pointer.
 627  */
 628 static irqreturn_t
 629 ds1685_rtc_irq_handler(int irq, void *dev_id)
 630 {
 631         struct platform_device *pdev = dev_id;
 632         struct ds1685_priv *rtc = platform_get_drvdata(pdev);
 633         struct mutex *rtc_mutex;
 634         u8 ctrlb, ctrlc;
 635         unsigned long events = 0;
 636         u8 num_irqs = 0;
 637
 638         /* Abort early if the device isn't ready yet (i.e., DEBUG_SHIRQ). */
 639         if (unlikely(!rtc))
 640                 return IRQ_HANDLED;
 641
 642         rtc_mutex = &rtc->dev->ops_lock;
 643         mutex_lock(rtc_mutex);
 644
 645         /* Ctrlb holds the interrupt-enable bits and ctrlc the flag bits. */
 646         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 647         ctrlc = rtc->read(rtc, RTC_CTRL_C);
 648
 649         /* Is the IRQF bit set? */
 650         if (likely(ctrlc & RTC_CTRL_C_IRQF)) {
 651                 /*
 652                  * We need to determine if it was one of the standard
 653                  * events: PF, AF, or UF.  If so, we handle them and
 654                  * update the RTC core.
 655                  */
 656                 if (likely(ctrlc & RTC_CTRL_B_PAU_MASK)) {
 657                         events = RTC_IRQF;
 658
 659                         /* Check for a periodic interrupt. */
 660                         if ((ctrlb & RTC_CTRL_B_PIE) &&
 661                             (ctrlc & RTC_CTRL_C_PF)) {
 662                                 events |= RTC_PF;
 663                                 num_irqs++;
 664                         }
 665
 666                         /* Check for an alarm interrupt. */
 667                         if ((ctrlb & RTC_CTRL_B_AIE) &&
 668                             (ctrlc & RTC_CTRL_C_AF)) {
 669                                 events |= RTC_AF;
 670                                 num_irqs++;
 671                         }
 672
 673                         /* Check for an update interrupt. */
 674                         if ((ctrlb & RTC_CTRL_B_UIE) &&
 675                             (ctrlc & RTC_CTRL_C_UF)) {
 676                                 events |= RTC_UF;
 677                                 num_irqs++;
 678                         }
 679                 } else {
 680                         /*
 681                          * One of the "extended" interrupts was received that
 682                          * is not recognized by the RTC core.
 683                          */
 684                         ds1685_rtc_extended_irq(rtc, pdev);
 685                 }
 686         }
 687         rtc_update_irq(rtc->dev, num_irqs, events);
 688         mutex_unlock(rtc_mutex);
 689
 690         return events ? IRQ_HANDLED : IRQ_NONE;
 691 }
 692 /* ----------------------------------------------------------------------- */
 693
 694
 695 /* ----------------------------------------------------------------------- */
 696 /* ProcFS interface */
 697
 698 #ifdef CONFIG_PROC_FS
 699 #define NUM_REGS        6       /* Num of control registers. */
 700 #define NUM_BITS        8       /* Num bits per register. */
 701 #define NUM_SPACES      4       /* Num spaces between each bit. */
 702
 703 /*
 704  * Periodic Interrupt Rates.
 705  */
 706 static const char *ds1685_rtc_pirq_rate[16] = {
 707         "none", "3.90625ms", "7.8125ms", "0.122070ms", "0.244141ms",
 708         "0.488281ms", "0.9765625ms", "1.953125ms", "3.90625ms", "7.8125ms",
 709         "15.625ms", "31.25ms", "62.5ms", "125ms", "250ms", "500ms"
 710 };
 711
 712 /*
 713  * Square-Wave Output Frequencies.
 714  */
 715 static const char *ds1685_rtc_sqw_freq[16] = {
 716         "none", "256Hz", "128Hz", "8192Hz", "4096Hz", "2048Hz", "1024Hz",
 717         "512Hz", "256Hz", "128Hz", "64Hz", "32Hz", "16Hz", "8Hz", "4Hz", "2Hz"
 718 };
 719
 720 /**
 721  * ds1685_rtc_proc - procfs access function.
 722  * @dev: pointer to device structure.
 723  * @seq: pointer to seq_file structure.
 724  */
 725 static int
 726 ds1685_rtc_proc(struct device *dev, struct seq_file *seq)
 727 {
 728         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 729         u8 ctrla, ctrlb, ctrlc, ctrld, ctrl4a, ctrl4b, ssn[8];
 730         char *model;
 731
 732         /* Read all the relevant data from the control registers. */
 733         ds1685_rtc_switch_to_bank1(rtc);
 734         ds1685_rtc_get_ssn(rtc, ssn);
 735         ctrla = rtc->read(rtc, RTC_CTRL_A);
 736         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 737         ctrlc = rtc->read(rtc, RTC_CTRL_C);
 738         ctrld = rtc->read(rtc, RTC_CTRL_D);
 739         ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
 740         ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
 741         ds1685_rtc_switch_to_bank0(rtc);
 742
 743         /* Determine the RTC model. */
 744         switch (ssn[0]) {
 745         case RTC_MODEL_DS1685:
 746                 model = "DS1685/DS1687\0";
 747                 break;
 748         case RTC_MODEL_DS1689:
 749                 model = "DS1689/DS1693\0";
 750                 break;
 751         case RTC_MODEL_DS17285:
 752                 model = "DS17285/DS17287\0";
 753                 break;
 754         case RTC_MODEL_DS17485:
 755                 model = "DS17485/DS17487\0";
 756                 break;
 757         case RTC_MODEL_DS17885:
 758                 model = "DS17885/DS17887\0";
 759                 break;
 760         default:
 761                 model = "Unknown\0";
 762                 break;
 763         }
 764
 765         /* Print out the information. */
 766         seq_printf(seq,
 767            "Model\t\t: %s\n"
 768            "Oscillator\t: %s\n"
 769            "12/24hr\t\t: %s\n"
 770            "DST\t\t: %s\n"
 771            "Data mode\t: %s\n"
 772            "Battery\t\t: %s\n"
 773            "Aux batt\t: %s\n"
 774            "Update IRQ\t: %s\n"
 775            "Periodic IRQ\t: %s\n"
 776            "Periodic Rate\t: %s\n"
 777            "SQW Freq\t: %s\n"
 778            "Serial #\t: %8phC\n",
 779            model,
 780            ((ctrla & RTC_CTRL_A_DV1) ? "enabled" : "disabled"),
 781            ((ctrlb & RTC_CTRL_B_2412) ? "24-hour" : "12-hour"),
 782            ((ctrlb & RTC_CTRL_B_DSE) ? "enabled" : "disabled"),
 783            ((ctrlb & RTC_CTRL_B_DM) ? "binary" : "BCD"),
 784            ((ctrld & RTC_CTRL_D_VRT) ? "ok" : "exhausted or n/a"),
 785            ((ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "exhausted or n/a"),
 786            ((ctrlb & RTC_CTRL_B_UIE) ? "yes" : "no"),
 787            ((ctrlb & RTC_CTRL_B_PIE) ? "yes" : "no"),
 788            (!(ctrl4b & RTC_CTRL_4B_E32K) ?
 789             ds1685_rtc_pirq_rate[(ctrla & RTC_CTRL_A_RS_MASK)] : "none"),
 790            (!((ctrl4b & RTC_CTRL_4B_E32K)) ?
 791             ds1685_rtc_sqw_freq[(ctrla & RTC_CTRL_A_RS_MASK)] : "32768Hz"),
 792            ssn);
 793         return 0;
 794 }
 795 #else
 796 #define ds1685_rtc_proc NULL
 797 #endif /* CONFIG_PROC_FS */
 798 /* ----------------------------------------------------------------------- */
 799
 800
 801 /* ----------------------------------------------------------------------- */
 802 /* RTC Class operations */
 803
 804 static const struct rtc_class_ops
 805 ds1685_rtc_ops = {
 806         .proc = ds1685_rtc_proc,
 807         .read_time = ds1685_rtc_read_time,
 808         .set_time = ds1685_rtc_set_time,
 809         .read_alarm = ds1685_rtc_read_alarm,
 810         .set_alarm = ds1685_rtc_set_alarm,
 811         .alarm_irq_enable = ds1685_rtc_alarm_irq_enable,
 812 };
 813 /* ----------------------------------------------------------------------- */
 814
 815 static int ds1685_nvram_read(void *priv, unsigned int pos, void *val,
 816                              size_t size)
 817 {
 818         struct ds1685_priv *rtc = priv;
 819         struct mutex *rtc_mutex = &rtc->dev->ops_lock;
 820         ssize_t count;
 821         u8 *buf = val;
 822         int err;
 823
 824         err = mutex_lock_interruptible(rtc_mutex);
 825         if (err)
 826                 return err;
 827
 828         ds1685_rtc_switch_to_bank0(rtc);
 829
 830         /* Read NVRAM in time and bank0 registers. */
 831         for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
 832              count++, size--) {
 833                 if (count < NVRAM_SZ_TIME)
 834                         *buf++ = rtc->read(rtc, (NVRAM_TIME_BASE + pos++));
 835                 else
 836                         *buf++ = rtc->read(rtc, (NVRAM_BANK0_BASE + pos++));
 837         }
 838
 839 #ifndef CONFIG_RTC_DRV_DS1689
 840         if (size > 0) {
 841                 ds1685_rtc_switch_to_bank1(rtc);
 842
 843 #ifndef CONFIG_RTC_DRV_DS1685
 844                 /* Enable burst-mode on DS17x85/DS17x87 */
 845                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 846                            (rtc->read(rtc, RTC_EXT_CTRL_4A) |
 847                             RTC_CTRL_4A_BME));
 848
 849                 /* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
 850                  * reading with burst-mode */
 851                 rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
 852                            (pos - NVRAM_TOTAL_SZ_BANK0));
 853 #endif
 854
 855                 /* Read NVRAM in bank1 registers. */
 856                 for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
 857                      count++, size--) {
 858 #ifdef CONFIG_RTC_DRV_DS1685
 859                         /* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
 860                          * before each read. */
 861                         rtc->write(rtc, RTC_BANK1_RAM_ADDR,
 862                                    (pos - NVRAM_TOTAL_SZ_BANK0));
 863 #endif
 864                         *buf++ = rtc->read(rtc, RTC_BANK1_RAM_DATA_PORT);
 865                         pos++;
 866                 }
 867
 868 #ifndef CONFIG_RTC_DRV_DS1685
 869                 /* Disable burst-mode on DS17x85/DS17x87 */
 870                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 871                            (rtc->read(rtc, RTC_EXT_CTRL_4A) &
 872                             ~(RTC_CTRL_4A_BME)));
 873 #endif
 874                 ds1685_rtc_switch_to_bank0(rtc);
 875         }
 876 #endif /* !CONFIG_RTC_DRV_DS1689 */
 877         mutex_unlock(rtc_mutex);
 878
 879         return 0;
 880 }
 881
 882 static int ds1685_nvram_write(void *priv, unsigned int pos, void *val,
 883                               size_t size)
 884 {
 885         struct ds1685_priv *rtc = priv;
 886         struct mutex *rtc_mutex = &rtc->dev->ops_lock;
 887         ssize_t count;
 888         u8 *buf = val;
 889         int err;
 890
 891         err = mutex_lock_interruptible(rtc_mutex);
 892         if (err)
 893                 return err;
 894
 895         ds1685_rtc_switch_to_bank0(rtc);
 896
 897         /* Write NVRAM in time and bank0 registers. */
 898         for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
 899              count++, size--)
 900                 if (count < NVRAM_SZ_TIME)
 901                         rtc->write(rtc, (NVRAM_TIME_BASE + pos++),
 902                                    *buf++);
 903                 else
 904                         rtc->write(rtc, (NVRAM_BANK0_BASE), *buf++);
 905
 906 #ifndef CONFIG_RTC_DRV_DS1689
 907         if (size > 0) {
 908                 ds1685_rtc_switch_to_bank1(rtc);
 909
 910 #ifndef CONFIG_RTC_DRV_DS1685
 911                 /* Enable burst-mode on DS17x85/DS17x87 */
 912                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 913                            (rtc->read(rtc, RTC_EXT_CTRL_4A) |
 914                             RTC_CTRL_4A_BME));
 915
 916                 /* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
 917                  * writing with burst-mode */
 918                 rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
 919                            (pos - NVRAM_TOTAL_SZ_BANK0));
 920 #endif
 921
 922                 /* Write NVRAM in bank1 registers. */
 923                 for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
 924                      count++, size--) {
 925 #ifdef CONFIG_RTC_DRV_DS1685
 926                         /* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
 927                          * before each read. */
 928                         rtc->write(rtc, RTC_BANK1_RAM_ADDR,
 929                                    (pos - NVRAM_TOTAL_SZ_BANK0));
 930 #endif
 931                         rtc->write(rtc, RTC_BANK1_RAM_DATA_PORT, *buf++);
 932                         pos++;
 933                 }
 934
 935 #ifndef CONFIG_RTC_DRV_DS1685
 936                 /* Disable burst-mode on DS17x85/DS17x87 */
 937                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 938                            (rtc->read(rtc, RTC_EXT_CTRL_4A) &
 939                             ~(RTC_CTRL_4A_BME)));
 940 #endif
 941                 ds1685_rtc_switch_to_bank0(rtc);
 942         }
 943 #endif /* !CONFIG_RTC_DRV_DS1689 */
 944         mutex_unlock(rtc_mutex);
 945
 946         return 0;
 947 }
 948
 949 /* ----------------------------------------------------------------------- */
 950 /* SysFS interface */
 951
 952 /**
 953  * ds1685_rtc_sysfs_battery_show - sysfs file for main battery status.
 954  * @dev: pointer to device structure.
 955  * @attr: pointer to device_attribute structure.
 956  * @buf: pointer to char array to hold the output.
 957  */
 958 static ssize_t
 959 ds1685_rtc_sysfs_battery_show(struct device *dev,
 960                               struct device_attribute *attr, char *buf)
 961 {
 962         struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
 963         u8 ctrld;
 964
 965         ctrld = rtc->read(rtc, RTC_CTRL_D);
 966
 967         return sprintf(buf, "%s\n",
 968                         (ctrld & RTC_CTRL_D_VRT) ? "ok" : "not ok or N/A");
 969 }
 970 static DEVICE_ATTR(battery, S_IRUGO, ds1685_rtc_sysfs_battery_show, NULL);
 971
 972 /**
 973  * ds1685_rtc_sysfs_auxbatt_show - sysfs file for aux battery status.
 974  * @dev: pointer to device structure.
 975  * @attr: pointer to device_attribute structure.
 976  * @buf: pointer to char array to hold the output.
 977  */
 978 static ssize_t
 979 ds1685_rtc_sysfs_auxbatt_show(struct device *dev,
 980                               struct device_attribute *attr, char *buf)
 981 {
 982         struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
 983         u8 ctrl4a;
 984
 985         ds1685_rtc_switch_to_bank1(rtc);
 986         ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
 987         ds1685_rtc_switch_to_bank0(rtc);
 988
 989         return sprintf(buf, "%s\n",
 990                         (ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "not ok or N/A");
 991 }
 992 static DEVICE_ATTR(auxbatt, S_IRUGO, ds1685_rtc_sysfs_auxbatt_show, NULL);
 993
 994 /**
 995  * ds1685_rtc_sysfs_serial_show - sysfs file for silicon serial number.
 996  * @dev: pointer to device structure.
 997  * @attr: pointer to device_attribute structure.
 998  * @buf: pointer to char array to hold the output.
 999  */
1000 static ssize_t
1001 ds1685_rtc_sysfs_serial_show(struct device *dev,
1002                              struct device_attribute *attr, char *buf)
1003 {
1004         struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
1005         u8 ssn[8];
1006
1007         ds1685_rtc_switch_to_bank1(rtc);
1008         ds1685_rtc_get_ssn(rtc, ssn);
1009         ds1685_rtc_switch_to_bank0(rtc);
1010
1011         return sprintf(buf, "%8phC\n", ssn);
1012 }
1013 static DEVICE_ATTR(serial, S_IRUGO, ds1685_rtc_sysfs_serial_show, NULL);
1014
1015 /**
1016  * struct ds1685_rtc_sysfs_misc_attrs - list for misc RTC features.
1017  */
1018 static struct attribute*
1019 ds1685_rtc_sysfs_misc_attrs[] = {
1020         &dev_attr_battery.attr,
1021         &dev_attr_auxbatt.attr,
1022         &dev_attr_serial.attr,
1023         NULL,
1024 };
1025
1026 /**
1027  * struct ds1685_rtc_sysfs_misc_grp - attr group for misc RTC features.
1028  */
1029 static const struct attribute_group
1030 ds1685_rtc_sysfs_misc_grp = {
1031         .name = "misc",
1032         .attrs = ds1685_rtc_sysfs_misc_attrs,
1033 };
1034
1035 /* ----------------------------------------------------------------------- */
1036 /* Driver Probe/Removal */
1037
1038 /**
1039  * ds1685_rtc_probe - initializes rtc driver.
1040  * @pdev: pointer to platform_device structure.
1041  */
1042 static int
1043 ds1685_rtc_probe(struct platform_device *pdev)
1044 {
1045         struct rtc_device *rtc_dev;
1046         struct resource *res;
1047         struct ds1685_priv *rtc;
1048         struct ds1685_rtc_platform_data *pdata;
1049         u8 ctrla, ctrlb, hours;
1050         unsigned char am_pm;
1051         int ret = 0;
1052         struct nvmem_config nvmem_cfg = {
1053                 .name = "ds1685_nvram",
1054                 .size = NVRAM_TOTAL_SZ,
1055                 .reg_read = ds1685_nvram_read,
1056                 .reg_write = ds1685_nvram_write,
1057         };
1058
1059         /* Get the platform data. */
1060         pdata = (struct ds1685_rtc_platform_data *) pdev->dev.platform_data;
1061         if (!pdata)
1062                 return -ENODEV;
1063
1064         /* Allocate memory for the rtc device. */
1065         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
1066         if (!rtc)
1067                 return -ENOMEM;
1068
1069         /*
1070          * Allocate/setup any IORESOURCE_MEM resources, if required.  Not all
1071          * platforms put the RTC in an easy-access place.  Like the SGI Octane,
1072          * which attaches the RTC to a "ByteBus", hooked to a SuperIO chip
1073          * that sits behind the IOC3 PCI metadevice.
1074          */
1075         if (pdata->alloc_io_resources) {
1076                 /* Get the platform resources. */
1077                 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1078                 if (!res)
1079                         return -ENXIO;
1080                 rtc->size = resource_size(res);
1081
1082                 /* Request a memory region. */
1083                 /* XXX: mmio-only for now. */
1084                 if (!devm_request_mem_region(&pdev->dev, res->start, rtc->size,
1085                                              pdev->name))
1086                         return -EBUSY;
1087
1088                 /*
1089                  * Set the base address for the rtc, and ioremap its
1090                  * registers.
1091                  */
1092                 rtc->baseaddr = res->start;
1093                 rtc->regs = devm_ioremap(&pdev->dev, res->start, rtc->size);
1094                 if (!rtc->regs)
1095                         return -ENOMEM;
1096         }
1097         rtc->alloc_io_resources = pdata->alloc_io_resources;
1098
1099         /* Get the register step size. */
1100         if (pdata->regstep > 0)
1101                 rtc->regstep = pdata->regstep;
1102         else
1103                 rtc->regstep = 1;
1104
1105         /* Platform read function, else default if mmio setup */
1106         if (pdata->plat_read)
1107                 rtc->read = pdata->plat_read;
1108         else
1109                 if (pdata->alloc_io_resources)
1110                         rtc->read = ds1685_read;
1111                 else
1112                         return -ENXIO;
1113
1114         /* Platform write function, else default if mmio setup */
1115         if (pdata->plat_write)
1116                 rtc->write = pdata->plat_write;
1117         else
1118                 if (pdata->alloc_io_resources)
1119                         rtc->write = ds1685_write;
1120                 else
1121                         return -ENXIO;
1122
1123         /* Platform pre-shutdown function, if defined. */
1124         if (pdata->plat_prepare_poweroff)
1125                 rtc->prepare_poweroff = pdata->plat_prepare_poweroff;
1126
1127         /* Platform wake_alarm function, if defined. */
1128         if (pdata->plat_wake_alarm)
1129                 rtc->wake_alarm = pdata->plat_wake_alarm;
1130
1131         /* Platform post_ram_clear function, if defined. */
1132         if (pdata->plat_post_ram_clear)
1133                 rtc->post_ram_clear = pdata->plat_post_ram_clear;
1134
1135         /* set the driver data. */
1136         platform_set_drvdata(pdev, rtc);
1137
1138         /* Turn the oscillator on if is not already on (DV1 = 1). */
1139         ctrla = rtc->read(rtc, RTC_CTRL_A);
1140         if (!(ctrla & RTC_CTRL_A_DV1))
1141                 ctrla |= RTC_CTRL_A_DV1;
1142
1143         /* Enable the countdown chain (DV2 = 0) */
1144         ctrla &= ~(RTC_CTRL_A_DV2);
1145
1146         /* Clear RS3-RS0 in Control A. */
1147         ctrla &= ~(RTC_CTRL_A_RS_MASK);
1148
1149         /*
1150          * All done with Control A.  Switch to Bank 1 for the remainder of
1151          * the RTC setup so we have access to the extended functions.
1152          */
1153         ctrla |= RTC_CTRL_A_DV0;
1154         rtc->write(rtc, RTC_CTRL_A, ctrla);
1155
1156         /* Default to 32768kHz output. */
1157         rtc->write(rtc, RTC_EXT_CTRL_4B,
1158                    (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_E32K));
1159
1160         /* Set the SET bit in Control B so we can do some housekeeping. */
1161         rtc->write(rtc, RTC_CTRL_B,
1162                    (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
1163
1164         /* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
1165         while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
1166                 cpu_relax();
1167
1168         /*
1169          * If the platform supports BCD mode, then set DM=0 in Control B.
1170          * Otherwise, set DM=1 for BIN mode.
1171          */
1172         ctrlb = rtc->read(rtc, RTC_CTRL_B);
1173         if (pdata->bcd_mode)
1174                 ctrlb &= ~(RTC_CTRL_B_DM);
1175         else
1176                 ctrlb |= RTC_CTRL_B_DM;
1177         rtc->bcd_mode = pdata->bcd_mode;
1178
1179         /*
1180          * Disable Daylight Savings Time (DSE = 0).
1181          * The RTC has hardcoded timezone information that is rendered
1182          * obselete.  We'll let the OS deal with DST settings instead.
1183          */
1184         if (ctrlb & RTC_CTRL_B_DSE)
1185                 ctrlb &= ~(RTC_CTRL_B_DSE);
1186
1187         /* Force 24-hour mode (2412 = 1). */
1188         if (!(ctrlb & RTC_CTRL_B_2412)) {
1189                 /* Reinitialize the time hours. */
1190                 hours = rtc->read(rtc, RTC_HRS);
1191                 am_pm = hours & RTC_HRS_AMPM_MASK;
1192                 hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
1193                                            RTC_HRS_12_BIN_MASK);
1194                 hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
1195
1196                 /* Enable 24-hour mode. */
1197                 ctrlb |= RTC_CTRL_B_2412;
1198
1199                 /* Write back to Control B, including DM & DSE bits. */
1200                 rtc->write(rtc, RTC_CTRL_B, ctrlb);
1201
1202                 /* Write the time hours back. */
1203                 rtc->write(rtc, RTC_HRS,
1204                            ds1685_rtc_bin2bcd(rtc, hours,
1205                                               RTC_HRS_24_BIN_MASK,
1206                                               RTC_HRS_24_BCD_MASK));
1207
1208                 /* Reinitialize the alarm hours. */
1209                 hours = rtc->read(rtc, RTC_HRS_ALARM);
1210                 am_pm = hours & RTC_HRS_AMPM_MASK;
1211                 hours = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_12_BCD_MASK,
1212                                            RTC_HRS_12_BIN_MASK);
1213                 hours = ((hours == 12) ? 0 : ((am_pm) ? hours + 12 : hours));
1214
1215                 /* Write the alarm hours back. */
1216                 rtc->write(rtc, RTC_HRS_ALARM,
1217                            ds1685_rtc_bin2bcd(rtc, hours,
1218                                               RTC_HRS_24_BIN_MASK,
1219                                               RTC_HRS_24_BCD_MASK));
1220         } else {
1221                 /* 24-hour mode is already set, so write Control B back. */
1222                 rtc->write(rtc, RTC_CTRL_B, ctrlb);
1223         }
1224
1225         /* Unset the SET bit in Control B so the RTC can update. */
1226         rtc->write(rtc, RTC_CTRL_B,
1227                    (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
1228
1229         /* Check the main battery. */
1230         if (!(rtc->read(rtc, RTC_CTRL_D) & RTC_CTRL_D_VRT))
1231                 dev_warn(&pdev->dev,
1232                          "Main battery is exhausted! RTC may be invalid!\n");
1233
1234         /* Check the auxillary battery.  It is optional. */
1235         if (!(rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_VRT2))
1236                 dev_warn(&pdev->dev,
1237                          "Aux battery is exhausted or not available.\n");
1238
1239         /* Read Ctrl B and clear PIE/AIE/UIE. */
1240         rtc->write(rtc, RTC_CTRL_B,
1241                    (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_PAU_MASK)));
1242
1243         /* Reading Ctrl C auto-clears PF/AF/UF. */
1244         rtc->read(rtc, RTC_CTRL_C);
1245
1246         /* Read Ctrl 4B and clear RIE/WIE/KSE. */
1247         rtc->write(rtc, RTC_EXT_CTRL_4B,
1248                    (rtc->read(rtc, RTC_EXT_CTRL_4B) & ~(RTC_CTRL_4B_RWK_MASK)));
1249
1250         /* Clear RF/WF/KF in Ctrl 4A. */
1251         rtc->write(rtc, RTC_EXT_CTRL_4A,
1252                    (rtc->read(rtc, RTC_EXT_CTRL_4A) & ~(RTC_CTRL_4A_RWK_MASK)));
1253
1254         /*
1255          * Re-enable KSE to handle power button events.  We do not enable
1256          * WIE or RIE by default.
1257          */
1258         rtc->write(rtc, RTC_EXT_CTRL_4B,
1259                    (rtc->read(rtc, RTC_EXT_CTRL_4B) | RTC_CTRL_4B_KSE));
1260
1261         rtc_dev = devm_rtc_allocate_device(&pdev->dev);
1262         if (IS_ERR(rtc_dev))
1263                 return PTR_ERR(rtc_dev);
1264
1265         rtc_dev->ops = &ds1685_rtc_ops;
1266
1267         /* Century bit is useless because leap year fails in 1900 and 2100 */
1268         rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_2000;
1269         rtc_dev->range_max = RTC_TIMESTAMP_END_2099;
1270
1271         /* Maximum periodic rate is 8192Hz (0.122070ms). */
1272         rtc_dev->max_user_freq = RTC_MAX_USER_FREQ;
1273
1274         /* See if the platform doesn't support UIE. */
1275         if (pdata->uie_unsupported)
1276                 rtc_dev->uie_unsupported = 1;
1277         rtc->uie_unsupported = pdata->uie_unsupported;
1278
1279         rtc->dev = rtc_dev;
1280
1281         /*
1282          * Fetch the IRQ and setup the interrupt handler.
1283          *
1284          * Not all platforms have the IRQF pin tied to something.  If not, the
1285          * RTC will still set the *IE / *F flags and raise IRQF in ctrlc, but
1286          * there won't be an automatic way of notifying the kernel about it,
1287          * unless ctrlc is explicitly polled.
1288          */
1289         if (!pdata->no_irq) {
1290                 ret = platform_get_irq(pdev, 0);
1291                 if (ret <= 0)
1292                         return ret;
1293
1294                 rtc->irq_num = ret;
1295
1296                 /* Request an IRQ. */
1297                 ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_num,
1298                                        NULL, ds1685_rtc_irq_handler,
1299                                        IRQF_SHARED | IRQF_ONESHOT,
1300                                        pdev->name, pdev);
1301
1302                 /* Check to see if something came back. */
1303                 if (unlikely(ret)) {
1304                         dev_warn(&pdev->dev,
1305                                  "RTC interrupt not available\n");
1306                         rtc->irq_num = 0;
1307                 }
1308         }
1309         rtc->no_irq = pdata->no_irq;
1310
1311         /* Setup complete. */
1312         ds1685_rtc_switch_to_bank0(rtc);
1313
1314         ret = rtc_add_group(rtc_dev, &ds1685_rtc_sysfs_misc_grp);
1315         if (ret)
1316                 return ret;
1317
1318         rtc_dev->nvram_old_abi = true;
1319         nvmem_cfg.priv = rtc;
1320         ret = rtc_nvmem_register(rtc_dev, &nvmem_cfg);
1321         if (ret)
1322                 return ret;
1323
1324         return rtc_register_device(rtc_dev);
1325 }
1326
1327 /**
1328  * ds1685_rtc_remove - removes rtc driver.
1329  * @pdev: pointer to platform_device structure.
1330  */
1331 static int
1332 ds1685_rtc_remove(struct platform_device *pdev)
1333 {
1334         struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1335
1336         /* Read Ctrl B and clear PIE/AIE/UIE. */
1337         rtc->write(rtc, RTC_CTRL_B,
1338                    (rtc->read(rtc, RTC_CTRL_B) &
1339                     ~(RTC_CTRL_B_PAU_MASK)));
1340
1341         /* Reading Ctrl C auto-clears PF/AF/UF. */
1342         rtc->read(rtc, RTC_CTRL_C);
1343
1344         /* Read Ctrl 4B and clear RIE/WIE/KSE. */
1345         rtc->write(rtc, RTC_EXT_CTRL_4B,
1346                    (rtc->read(rtc, RTC_EXT_CTRL_4B) &
1347                     ~(RTC_CTRL_4B_RWK_MASK)));
1348
1349         /* Manually clear RF/WF/KF in Ctrl 4A. */
1350         rtc->write(rtc, RTC_EXT_CTRL_4A,
1351                    (rtc->read(rtc, RTC_EXT_CTRL_4A) &
1352                     ~(RTC_CTRL_4A_RWK_MASK)));
1353
1354         return 0;
1355 }
1356
1357 /**
1358  * ds1685_rtc_driver - rtc driver properties.
1359  */
1360 static struct platform_driver ds1685_rtc_driver = {
1361         .driver         = {
1362                 .name   = "rtc-ds1685",
1363         },
1364         .probe          = ds1685_rtc_probe,
1365         .remove         = ds1685_rtc_remove,
1366 };
1367 module_platform_driver(ds1685_rtc_driver);
1368 /* ----------------------------------------------------------------------- */
1369
1370
1371 /* ----------------------------------------------------------------------- */
1372 /* Poweroff function */
1373
1374 /**
1375  * ds1685_rtc_poweroff - uses the RTC chip to power the system off.
1376  * @pdev: pointer to platform_device structure.
1377  */
1378 void __noreturn
1379 ds1685_rtc_poweroff(struct platform_device *pdev)
1380 {
1381         u8 ctrla, ctrl4a, ctrl4b;
1382         struct ds1685_priv *rtc;
1383
1384         /* Check for valid RTC data, else, spin forever. */
1385         if (unlikely(!pdev)) {
1386                 pr_emerg("platform device data not available, spinning forever ...\n");
1387                 while(1);
1388                 unreachable();
1389         } else {
1390                 /* Get the rtc data. */
1391                 rtc = platform_get_drvdata(pdev);
1392
1393                 /*
1394                  * Disable our IRQ.  We're powering down, so we're not
1395                  * going to worry about cleaning up.  Most of that should
1396                  * have been taken care of by the shutdown scripts and this
1397                  * is the final function call.
1398                  */
1399                 if (!rtc->no_irq)
1400                         disable_irq_nosync(rtc->irq_num);
1401
1402                 /* Oscillator must be on and the countdown chain enabled. */
1403                 ctrla = rtc->read(rtc, RTC_CTRL_A);
1404                 ctrla |= RTC_CTRL_A_DV1;
1405                 ctrla &= ~(RTC_CTRL_A_DV2);
1406                 rtc->write(rtc, RTC_CTRL_A, ctrla);
1407
1408                 /*
1409                  * Read Control 4A and check the status of the auxillary
1410                  * battery.  This must be present and working (VRT2 = 1)
1411                  * for wakeup and kickstart functionality to be useful.
1412                  */
1413                 ds1685_rtc_switch_to_bank1(rtc);
1414                 ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
1415                 if (ctrl4a & RTC_CTRL_4A_VRT2) {
1416                         /* Clear all of the interrupt flags on Control 4A. */
1417                         ctrl4a &= ~(RTC_CTRL_4A_RWK_MASK);
1418                         rtc->write(rtc, RTC_EXT_CTRL_4A, ctrl4a);
1419
1420                         /*
1421                          * The auxillary battery is present and working.
1422                          * Enable extended functions (ABE=1), enable
1423                          * wake-up (WIE=1), and enable kickstart (KSE=1)
1424                          * in Control 4B.
1425                          */
1426                         ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
1427                         ctrl4b |= (RTC_CTRL_4B_ABE | RTC_CTRL_4B_WIE |
1428                                    RTC_CTRL_4B_KSE);
1429                         rtc->write(rtc, RTC_EXT_CTRL_4B, ctrl4b);
1430                 }
1431
1432                 /* Set PAB to 1 in Control 4A to power the system down. */
1433                 dev_warn(&pdev->dev, "Powerdown.\n");
1434                 msleep(20);
1435                 rtc->write(rtc, RTC_EXT_CTRL_4A,
1436                            (ctrl4a | RTC_CTRL_4A_PAB));
1437
1438                 /* Spin ... we do not switch back to bank0. */
1439                 while(1);
1440                 unreachable();
1441         }
1442 }
1443 EXPORT_SYMBOL(ds1685_rtc_poweroff);
1444 /* ----------------------------------------------------------------------- */
1445
1446
1447 MODULE_AUTHOR("Joshua Kinard <kumba@gentoo.org>");
1448 MODULE_AUTHOR("Matthias Fuchs <matthias.fuchs@esd-electronics.com>");
1449 MODULE_DESCRIPTION("Dallas/Maxim DS1685/DS1687-series RTC driver");
1450 MODULE_LICENSE("GPL");
1451 MODULE_ALIAS("platform:rtc-ds1685");