drivers/rtc/rtc-ds1685.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * An rtc driver for the Dallas/Maxim DS1685/DS1687 and related real-time
   4  * chips.
   5  *
   6  * Copyright (C) 2011-2014 Joshua Kinard <kumba@gentoo.org>.
   7  * Copyright (C) 2009 Matthias Fuchs <matthias.fuchs@esd-electronics.com>.
   8  *
   9  * References:
  10  *    DS1685/DS1687 3V/5V Real-Time Clocks, 19-5215, Rev 4/10.
  11  *    DS17x85/DS17x87 3V/5V Real-Time Clocks, 19-5222, Rev 4/10.
  12  *    DS1689/DS1693 3V/5V Serialized Real-Time Clocks, Rev 112105.
  13  *    Application Note 90, Using the Multiplex Bus RTC Extended Features.
  14  */
  15
  16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18 #include <linux/bcd.h>
  19 #include <linux/delay.h>
  20 #include <linux/io.h>
  21 #include <linux/module.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/rtc.h>
  24 #include <linux/workqueue.h>
  25
  26 #include <linux/rtc/ds1685.h>
  27
  28 #ifdef CONFIG_PROC_FS
  29 #include <linux/proc_fs.h>
  30 #endif
  31
  32
  33 /* ----------------------------------------------------------------------- */
  34 /*
  35  *  Standard read/write
  36  *  all registers are mapped in CPU address space
  37  */
  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  * Indirect read/write functions
  67  * access happens via address and data register mapped in CPU address space
  68  */
  69
  70 /**
  71  * ds1685_indirect_read - read a value from an rtc register.
  72  * @rtc: pointer to the ds1685 rtc structure.
  73  * @reg: the register address to read.
  74  */
  75 static u8
  76 ds1685_indirect_read(struct ds1685_priv *rtc, int reg)
  77 {
  78         writeb(reg, rtc->regs);
  79         return readb(rtc->data);
  80 }
  81
  82 /**
  83  * ds1685_indirect_write - write a value to an rtc register.
  84  * @rtc: pointer to the ds1685 rtc structure.
  85  * @reg: the register address to write.
  86  * @value: value to write to the register.
  87  */
  88 static void
  89 ds1685_indirect_write(struct ds1685_priv *rtc, int reg, u8 value)
  90 {
  91         writeb(reg, rtc->regs);
  92         writeb(value, rtc->data);
  93 }
  94
  95 /* ----------------------------------------------------------------------- */
  96 /* Inlined functions */
  97
  98 /**
  99  * ds1685_rtc_bcd2bin - bcd2bin wrapper in case platform doesn't support BCD.
 100  * @rtc: pointer to the ds1685 rtc structure.
 101  * @val: u8 time value to consider converting.
 102  * @bcd_mask: u8 mask value if BCD mode is used.
 103  * @bin_mask: u8 mask value if BIN mode is used.
 104  *
 105  * Returns the value, converted to BIN if originally in BCD and bcd_mode TRUE.
 106  */
 107 static inline u8
 108 ds1685_rtc_bcd2bin(struct ds1685_priv *rtc, u8 val, u8 bcd_mask, u8 bin_mask)
 109 {
 110         if (rtc->bcd_mode)
 111                 return (bcd2bin(val) & bcd_mask);
 112
 113         return (val & bin_mask);
 114 }
 115
 116 /**
 117  * ds1685_rtc_bin2bcd - bin2bcd wrapper in case platform doesn't support BCD.
 118  * @rtc: pointer to the ds1685 rtc structure.
 119  * @val: u8 time value to consider converting.
 120  * @bin_mask: u8 mask value if BIN mode is used.
 121  * @bcd_mask: u8 mask value if BCD mode is used.
 122  *
 123  * Returns the value, converted to BCD if originally in BIN and bcd_mode TRUE.
 124  */
 125 static inline u8
 126 ds1685_rtc_bin2bcd(struct ds1685_priv *rtc, u8 val, u8 bin_mask, u8 bcd_mask)
 127 {
 128         if (rtc->bcd_mode)
 129                 return (bin2bcd(val) & bcd_mask);
 130
 131         return (val & bin_mask);
 132 }
 133
 134 /**
 135  * s1685_rtc_check_mday - check validity of the day of month.
 136  * @rtc: pointer to the ds1685 rtc structure.
 137  * @mday: day of month.
 138  *
 139  * Returns -EDOM if the day of month is not within 1..31 range.
 140  */
 141 static inline int
 142 ds1685_rtc_check_mday(struct ds1685_priv *rtc, u8 mday)
 143 {
 144         if (rtc->bcd_mode) {
 145                 if (mday < 0x01 || mday > 0x31 || (mday & 0x0f) > 0x09)
 146                         return -EDOM;
 147         } else {
 148                 if (mday < 1 || mday > 31)
 149                         return -EDOM;
 150         }
 151         return 0;
 152 }
 153
 154 /**
 155  * ds1685_rtc_switch_to_bank0 - switch the rtc to bank 0.
 156  * @rtc: pointer to the ds1685 rtc structure.
 157  */
 158 static inline void
 159 ds1685_rtc_switch_to_bank0(struct ds1685_priv *rtc)
 160 {
 161         rtc->write(rtc, RTC_CTRL_A,
 162                    (rtc->read(rtc, RTC_CTRL_A) & ~(RTC_CTRL_A_DV0)));
 163 }
 164
 165 /**
 166  * ds1685_rtc_switch_to_bank1 - switch the rtc to bank 1.
 167  * @rtc: pointer to the ds1685 rtc structure.
 168  */
 169 static inline void
 170 ds1685_rtc_switch_to_bank1(struct ds1685_priv *rtc)
 171 {
 172         rtc->write(rtc, RTC_CTRL_A,
 173                    (rtc->read(rtc, RTC_CTRL_A) | RTC_CTRL_A_DV0));
 174 }
 175
 176 /**
 177  * ds1685_rtc_begin_data_access - prepare the rtc for data access.
 178  * @rtc: pointer to the ds1685 rtc structure.
 179  *
 180  * This takes several steps to prepare the rtc for access to get/set time
 181  * and alarm values from the rtc registers:
 182  *  - Sets the SET bit in Control Register B.
 183  *  - Reads Ext Control Register 4A and checks the INCR bit.
 184  *  - If INCR is active, a short delay is added before Ext Control Register 4A
 185  *    is read again in a loop until INCR is inactive.
 186  *  - Switches the rtc to bank 1.  This allows access to all relevant
 187  *    data for normal rtc operation, as bank 0 contains only the nvram.
 188  */
 189 static inline void
 190 ds1685_rtc_begin_data_access(struct ds1685_priv *rtc)
 191 {
 192         /* Set the SET bit in Ctrl B */
 193         rtc->write(rtc, RTC_CTRL_B,
 194                    (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET));
 195
 196         /* Switch to Bank 1 */
 197         ds1685_rtc_switch_to_bank1(rtc);
 198
 199         /* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */
 200         while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR)
 201                 cpu_relax();
 202 }
 203
 204 /**
 205  * ds1685_rtc_end_data_access - end data access on the rtc.
 206  * @rtc: pointer to the ds1685 rtc structure.
 207  *
 208  * This ends what was started by ds1685_rtc_begin_data_access:
 209  *  - Switches the rtc back to bank 0.
 210  *  - Clears the SET bit in Control Register B.
 211  */
 212 static inline void
 213 ds1685_rtc_end_data_access(struct ds1685_priv *rtc)
 214 {
 215         /* Switch back to Bank 0 */
 216         ds1685_rtc_switch_to_bank0(rtc);
 217
 218         /* Clear the SET bit in Ctrl B */
 219         rtc->write(rtc, RTC_CTRL_B,
 220                    (rtc->read(rtc, RTC_CTRL_B) & ~(RTC_CTRL_B_SET)));
 221 }
 222
 223 /**
 224  * ds1685_rtc_get_ssn - retrieve the silicon serial number.
 225  * @rtc: pointer to the ds1685 rtc structure.
 226  * @ssn: u8 array to hold the bits of the silicon serial number.
 227  *
 228  * This number starts at 0x40, and is 8-bytes long, ending at 0x47. The
 229  * first byte is the model number, the next six bytes are the serial number
 230  * digits, and the final byte is a CRC check byte.  Together, they form the
 231  * silicon serial number.
 232  *
 233  * These values are stored in bank1, so ds1685_rtc_switch_to_bank1 must be
 234  * called first before calling this function, else data will be read out of
 235  * the bank0 NVRAM.  Be sure to call ds1685_rtc_switch_to_bank0 when done.
 236  */
 237 static inline void
 238 ds1685_rtc_get_ssn(struct ds1685_priv *rtc, u8 *ssn)
 239 {
 240         ssn[0] = rtc->read(rtc, RTC_BANK1_SSN_MODEL);
 241         ssn[1] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_1);
 242         ssn[2] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_2);
 243         ssn[3] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_3);
 244         ssn[4] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_4);
 245         ssn[5] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_5);
 246         ssn[6] = rtc->read(rtc, RTC_BANK1_SSN_BYTE_6);
 247         ssn[7] = rtc->read(rtc, RTC_BANK1_SSN_CRC);
 248 }
 249 /* ----------------------------------------------------------------------- */
 250
 251
 252 /* ----------------------------------------------------------------------- */
 253 /* Read/Set Time & Alarm functions */
 254
 255 /**
 256  * ds1685_rtc_read_time - reads the time registers.
 257  * @dev: pointer to device structure.
 258  * @tm: pointer to rtc_time structure.
 259  */
 260 static int
 261 ds1685_rtc_read_time(struct device *dev, struct rtc_time *tm)
 262 {
 263         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 264         u8 century;
 265         u8 seconds, minutes, hours, wday, mday, month, years;
 266
 267         /* Fetch the time info from the RTC registers. */
 268         ds1685_rtc_begin_data_access(rtc);
 269         seconds = rtc->read(rtc, RTC_SECS);
 270         minutes = rtc->read(rtc, RTC_MINS);
 271         hours   = rtc->read(rtc, RTC_HRS);
 272         wday    = rtc->read(rtc, RTC_WDAY);
 273         mday    = rtc->read(rtc, RTC_MDAY);
 274         month   = rtc->read(rtc, RTC_MONTH);
 275         years   = rtc->read(rtc, RTC_YEAR);
 276         century = rtc->read(rtc, RTC_CENTURY);
 277         ds1685_rtc_end_data_access(rtc);
 278
 279         /* bcd2bin if needed, perform fixups, and store to rtc_time. */
 280         years        = ds1685_rtc_bcd2bin(rtc, years, RTC_YEAR_BCD_MASK,
 281                                           RTC_YEAR_BIN_MASK);
 282         century      = ds1685_rtc_bcd2bin(rtc, century, RTC_CENTURY_MASK,
 283                                           RTC_CENTURY_MASK);
 284         tm->tm_sec   = ds1685_rtc_bcd2bin(rtc, seconds, RTC_SECS_BCD_MASK,
 285                                           RTC_SECS_BIN_MASK);
 286         tm->tm_min   = ds1685_rtc_bcd2bin(rtc, minutes, RTC_MINS_BCD_MASK,
 287                                           RTC_MINS_BIN_MASK);
 288         tm->tm_hour  = ds1685_rtc_bcd2bin(rtc, hours, RTC_HRS_24_BCD_MASK,
 289                                           RTC_HRS_24_BIN_MASK);
 290         tm->tm_wday  = (ds1685_rtc_bcd2bin(rtc, wday, RTC_WDAY_MASK,
 291                                            RTC_WDAY_MASK) - 1);
 292         tm->tm_mday  = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
 293                                           RTC_MDAY_BIN_MASK);
 294         tm->tm_mon   = (ds1685_rtc_bcd2bin(rtc, month, RTC_MONTH_BCD_MASK,
 295                                            RTC_MONTH_BIN_MASK) - 1);
 296         tm->tm_year  = ((years + (century * 100)) - 1900);
 297         tm->tm_yday  = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 298         tm->tm_isdst = 0; /* RTC has hardcoded timezone, so don't use. */
 299
 300         return 0;
 301 }
 302
 303 /**
 304  * ds1685_rtc_set_time - sets the time registers.
 305  * @dev: pointer to device structure.
 306  * @tm: pointer to rtc_time structure.
 307  */
 308 static int
 309 ds1685_rtc_set_time(struct device *dev, struct rtc_time *tm)
 310 {
 311         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 312         u8 ctrlb, seconds, minutes, hours, wday, mday, month, years, century;
 313
 314         /* Fetch the time info from rtc_time. */
 315         seconds = ds1685_rtc_bin2bcd(rtc, tm->tm_sec, RTC_SECS_BIN_MASK,
 316                                      RTC_SECS_BCD_MASK);
 317         minutes = ds1685_rtc_bin2bcd(rtc, tm->tm_min, RTC_MINS_BIN_MASK,
 318                                      RTC_MINS_BCD_MASK);
 319         hours   = ds1685_rtc_bin2bcd(rtc, tm->tm_hour, RTC_HRS_24_BIN_MASK,
 320                                      RTC_HRS_24_BCD_MASK);
 321         wday    = ds1685_rtc_bin2bcd(rtc, (tm->tm_wday + 1), RTC_WDAY_MASK,
 322                                      RTC_WDAY_MASK);
 323         mday    = ds1685_rtc_bin2bcd(rtc, tm->tm_mday, RTC_MDAY_BIN_MASK,
 324                                      RTC_MDAY_BCD_MASK);
 325         month   = ds1685_rtc_bin2bcd(rtc, (tm->tm_mon + 1), RTC_MONTH_BIN_MASK,
 326                                      RTC_MONTH_BCD_MASK);
 327         years   = ds1685_rtc_bin2bcd(rtc, (tm->tm_year % 100),
 328                                      RTC_YEAR_BIN_MASK, RTC_YEAR_BCD_MASK);
 329         century = ds1685_rtc_bin2bcd(rtc, ((tm->tm_year + 1900) / 100),
 330                                      RTC_CENTURY_MASK, RTC_CENTURY_MASK);
 331
 332         /*
 333          * Perform Sanity Checks:
 334          *   - Months: !> 12, Month Day != 0.
 335          *   - Month Day !> Max days in current month.
 336          *   - Hours !>= 24, Mins !>= 60, Secs !>= 60, & Weekday !> 7.
 337          */
 338         if ((tm->tm_mon > 11) || (mday == 0))
 339                 return -EDOM;
 340
 341         if (tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year))
 342                 return -EDOM;
 343
 344         if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) ||
 345             (tm->tm_sec >= 60)  || (wday > 7))
 346                 return -EDOM;
 347
 348         /*
 349          * Set the data mode to use and store the time values in the
 350          * RTC registers.
 351          */
 352         ds1685_rtc_begin_data_access(rtc);
 353         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 354         if (rtc->bcd_mode)
 355                 ctrlb &= ~(RTC_CTRL_B_DM);
 356         else
 357                 ctrlb |= RTC_CTRL_B_DM;
 358         rtc->write(rtc, RTC_CTRL_B, ctrlb);
 359         rtc->write(rtc, RTC_SECS, seconds);
 360         rtc->write(rtc, RTC_MINS, minutes);
 361         rtc->write(rtc, RTC_HRS, hours);
 362         rtc->write(rtc, RTC_WDAY, wday);
 363         rtc->write(rtc, RTC_MDAY, mday);
 364         rtc->write(rtc, RTC_MONTH, month);
 365         rtc->write(rtc, RTC_YEAR, years);
 366         rtc->write(rtc, RTC_CENTURY, century);
 367         ds1685_rtc_end_data_access(rtc);
 368
 369         return 0;
 370 }
 371
 372 /**
 373  * ds1685_rtc_read_alarm - reads the alarm registers.
 374  * @dev: pointer to device structure.
 375  * @alrm: pointer to rtc_wkalrm structure.
 376  *
 377  * There are three primary alarm registers: seconds, minutes, and hours.
 378  * A fourth alarm register for the month date is also available in bank1 for
 379  * kickstart/wakeup features.  The DS1685/DS1687 manual states that a
 380  * "don't care" value ranging from 0xc0 to 0xff may be written into one or
 381  * more of the three alarm bytes to act as a wildcard value.  The fourth
 382  * byte doesn't support a "don't care" value.
 383  */
 384 static int
 385 ds1685_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 386 {
 387         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 388         u8 seconds, minutes, hours, mday, ctrlb, ctrlc;
 389         int ret;
 390
 391         /* Fetch the alarm info from the RTC alarm registers. */
 392         ds1685_rtc_begin_data_access(rtc);
 393         seconds = rtc->read(rtc, RTC_SECS_ALARM);
 394         minutes = rtc->read(rtc, RTC_MINS_ALARM);
 395         hours   = rtc->read(rtc, RTC_HRS_ALARM);
 396         mday    = rtc->read(rtc, RTC_MDAY_ALARM);
 397         ctrlb   = rtc->read(rtc, RTC_CTRL_B);
 398         ctrlc   = rtc->read(rtc, RTC_CTRL_C);
 399         ds1685_rtc_end_data_access(rtc);
 400
 401         /* Check the month date for validity. */
 402         ret = ds1685_rtc_check_mday(rtc, mday);
 403         if (ret)
 404                 return ret;
 405
 406         /*
 407          * Check the three alarm bytes.
 408          *
 409          * The Linux RTC system doesn't support the "don't care" capability
 410          * of this RTC chip.  We check for it anyways in case support is
 411          * added in the future and only assign when we care.
 412          */
 413         if (likely(seconds < 0xc0))
 414                 alrm->time.tm_sec = ds1685_rtc_bcd2bin(rtc, seconds,
 415                                                        RTC_SECS_BCD_MASK,
 416                                                        RTC_SECS_BIN_MASK);
 417
 418         if (likely(minutes < 0xc0))
 419                 alrm->time.tm_min = ds1685_rtc_bcd2bin(rtc, minutes,
 420                                                        RTC_MINS_BCD_MASK,
 421                                                        RTC_MINS_BIN_MASK);
 422
 423         if (likely(hours < 0xc0))
 424                 alrm->time.tm_hour = ds1685_rtc_bcd2bin(rtc, hours,
 425                                                         RTC_HRS_24_BCD_MASK,
 426                                                         RTC_HRS_24_BIN_MASK);
 427
 428         /* Write the data to rtc_wkalrm. */
 429         alrm->time.tm_mday = ds1685_rtc_bcd2bin(rtc, mday, RTC_MDAY_BCD_MASK,
 430                                                 RTC_MDAY_BIN_MASK);
 431         alrm->enabled = !!(ctrlb & RTC_CTRL_B_AIE);
 432         alrm->pending = !!(ctrlc & RTC_CTRL_C_AF);
 433
 434         return 0;
 435 }
 436
 437 /**
 438  * ds1685_rtc_set_alarm - sets the alarm in registers.
 439  * @dev: pointer to device structure.
 440  * @alrm: pointer to rtc_wkalrm structure.
 441  */
 442 static int
 443 ds1685_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 444 {
 445         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 446         u8 ctrlb, seconds, minutes, hours, mday;
 447         int ret;
 448
 449         /* Fetch the alarm info and convert to BCD. */
 450         seconds = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_sec,
 451                                      RTC_SECS_BIN_MASK,
 452                                      RTC_SECS_BCD_MASK);
 453         minutes = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_min,
 454                                      RTC_MINS_BIN_MASK,
 455                                      RTC_MINS_BCD_MASK);
 456         hours   = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_hour,
 457                                      RTC_HRS_24_BIN_MASK,
 458                                      RTC_HRS_24_BCD_MASK);
 459         mday    = ds1685_rtc_bin2bcd(rtc, alrm->time.tm_mday,
 460                                      RTC_MDAY_BIN_MASK,
 461                                      RTC_MDAY_BCD_MASK);
 462
 463         /* Check the month date for validity. */
 464         ret = ds1685_rtc_check_mday(rtc, mday);
 465         if (ret)
 466                 return ret;
 467
 468         /*
 469          * Check the three alarm bytes.
 470          *
 471          * The Linux RTC system doesn't support the "don't care" capability
 472          * of this RTC chip because rtc_valid_tm tries to validate every
 473          * field, and we only support four fields.  We put the support
 474          * here anyways for the future.
 475          */
 476         if (unlikely(seconds >= 0xc0))
 477                 seconds = 0xff;
 478
 479         if (unlikely(minutes >= 0xc0))
 480                 minutes = 0xff;
 481
 482         if (unlikely(hours >= 0xc0))
 483                 hours = 0xff;
 484
 485         alrm->time.tm_mon       = -1;
 486         alrm->time.tm_year      = -1;
 487         alrm->time.tm_wday      = -1;
 488         alrm->time.tm_yday      = -1;
 489         alrm->time.tm_isdst     = -1;
 490
 491         /* Disable the alarm interrupt first. */
 492         ds1685_rtc_begin_data_access(rtc);
 493         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 494         rtc->write(rtc, RTC_CTRL_B, (ctrlb & ~(RTC_CTRL_B_AIE)));
 495
 496         /* Read ctrlc to clear RTC_CTRL_C_AF. */
 497         rtc->read(rtc, RTC_CTRL_C);
 498
 499         /*
 500          * Set the data mode to use and store the time values in the
 501          * RTC registers.
 502          */
 503         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 504         if (rtc->bcd_mode)
 505                 ctrlb &= ~(RTC_CTRL_B_DM);
 506         else
 507                 ctrlb |= RTC_CTRL_B_DM;
 508         rtc->write(rtc, RTC_CTRL_B, ctrlb);
 509         rtc->write(rtc, RTC_SECS_ALARM, seconds);
 510         rtc->write(rtc, RTC_MINS_ALARM, minutes);
 511         rtc->write(rtc, RTC_HRS_ALARM, hours);
 512         rtc->write(rtc, RTC_MDAY_ALARM, mday);
 513
 514         /* Re-enable the alarm if needed. */
 515         if (alrm->enabled) {
 516                 ctrlb = rtc->read(rtc, RTC_CTRL_B);
 517                 ctrlb |= RTC_CTRL_B_AIE;
 518                 rtc->write(rtc, RTC_CTRL_B, ctrlb);
 519         }
 520
 521         /* Done! */
 522         ds1685_rtc_end_data_access(rtc);
 523
 524         return 0;
 525 }
 526 /* ----------------------------------------------------------------------- */
 527
 528
 529 /* ----------------------------------------------------------------------- */
 530 /* /dev/rtcX Interface functions */
 531
 532 /**
 533  * ds1685_rtc_alarm_irq_enable - replaces ioctl() RTC_AIE on/off.
 534  * @dev: pointer to device structure.
 535  * @enabled: flag indicating whether to enable or disable.
 536  */
 537 static int
 538 ds1685_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 539 {
 540         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 541
 542         /* Flip the requisite interrupt-enable bit. */
 543         if (enabled)
 544                 rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) |
 545                                              RTC_CTRL_B_AIE));
 546         else
 547                 rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) &
 548                                              ~(RTC_CTRL_B_AIE)));
 549
 550         /* Read Control C to clear all the flag bits. */
 551         rtc->read(rtc, RTC_CTRL_C);
 552
 553         return 0;
 554 }
 555 /* ----------------------------------------------------------------------- */
 556
 557
 558 /* ----------------------------------------------------------------------- */
 559 /* IRQ handler */
 560
 561 /**
 562  * ds1685_rtc_extended_irq - take care of extended interrupts
 563  * @rtc: pointer to the ds1685 rtc structure.
 564  * @pdev: platform device pointer.
 565  */
 566 static void
 567 ds1685_rtc_extended_irq(struct ds1685_priv *rtc, struct platform_device *pdev)
 568 {
 569         u8 ctrl4a, ctrl4b;
 570
 571         ds1685_rtc_switch_to_bank1(rtc);
 572         ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
 573         ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
 574
 575         /*
 576          * Check for a kickstart interrupt. With Vcc applied, this
 577          * typically means that the power button was pressed, so we
 578          * begin the shutdown sequence.
 579          */
 580         if ((ctrl4b & RTC_CTRL_4B_KSE) && (ctrl4a & RTC_CTRL_4A_KF)) {
 581                 /* Briefly disable kickstarts to debounce button presses. */
 582                 rtc->write(rtc, RTC_EXT_CTRL_4B,
 583                            (rtc->read(rtc, RTC_EXT_CTRL_4B) &
 584                             ~(RTC_CTRL_4B_KSE)));
 585
 586                 /* Clear the kickstart flag. */
 587                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 588                            (ctrl4a & ~(RTC_CTRL_4A_KF)));
 589
 590
 591                 /*
 592                  * Sleep 500ms before re-enabling kickstarts.  This allows
 593                  * adequate time to avoid reading signal jitter as additional
 594                  * button presses.
 595                  */
 596                 msleep(500);
 597                 rtc->write(rtc, RTC_EXT_CTRL_4B,
 598                            (rtc->read(rtc, RTC_EXT_CTRL_4B) |
 599                             RTC_CTRL_4B_KSE));
 600
 601                 /* Call the platform pre-poweroff function. Else, shutdown. */
 602                 if (rtc->prepare_poweroff != NULL)
 603                         rtc->prepare_poweroff();
 604                 else
 605                         ds1685_rtc_poweroff(pdev);
 606         }
 607
 608         /*
 609          * Check for a wake-up interrupt.  With Vcc applied, this is
 610          * essentially a second alarm interrupt, except it takes into
 611          * account the 'date' register in bank1 in addition to the
 612          * standard three alarm registers.
 613          */
 614         if ((ctrl4b & RTC_CTRL_4B_WIE) && (ctrl4a & RTC_CTRL_4A_WF)) {
 615                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 616                            (ctrl4a & ~(RTC_CTRL_4A_WF)));
 617
 618                 /* Call the platform wake_alarm function if defined. */
 619                 if (rtc->wake_alarm != NULL)
 620                         rtc->wake_alarm();
 621                 else
 622                         dev_warn(&pdev->dev,
 623                                  "Wake Alarm IRQ just occurred!\n");
 624         }
 625
 626         /*
 627          * Check for a ram-clear interrupt.  This happens if RIE=1 and RF=0
 628          * when RCE=1 in 4B.  This clears all NVRAM bytes in bank0 by setting
 629          * each byte to a logic 1.  This has no effect on any extended
 630          * NV-SRAM that might be present, nor on the time/calendar/alarm
 631          * registers.  After a ram-clear is completed, there is a minimum
 632          * recovery time of ~150ms in which all reads/writes are locked out.
 633          * NOTE: A ram-clear can still occur if RCE=1 and RIE=0.  We cannot
 634          * catch this scenario.
 635          */
 636         if ((ctrl4b & RTC_CTRL_4B_RIE) && (ctrl4a & RTC_CTRL_4A_RF)) {
 637                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 638                            (ctrl4a & ~(RTC_CTRL_4A_RF)));
 639                 msleep(150);
 640
 641                 /* Call the platform post_ram_clear function if defined. */
 642                 if (rtc->post_ram_clear != NULL)
 643                         rtc->post_ram_clear();
 644                 else
 645                         dev_warn(&pdev->dev,
 646                                  "RAM-Clear IRQ just occurred!\n");
 647         }
 648         ds1685_rtc_switch_to_bank0(rtc);
 649 }
 650
 651 /**
 652  * ds1685_rtc_irq_handler - IRQ handler.
 653  * @irq: IRQ number.
 654  * @dev_id: platform device pointer.
 655  */
 656 static irqreturn_t
 657 ds1685_rtc_irq_handler(int irq, void *dev_id)
 658 {
 659         struct platform_device *pdev = dev_id;
 660         struct ds1685_priv *rtc = platform_get_drvdata(pdev);
 661         u8 ctrlb, ctrlc;
 662         unsigned long events = 0;
 663         u8 num_irqs = 0;
 664
 665         /* Abort early if the device isn't ready yet (i.e., DEBUG_SHIRQ). */
 666         if (unlikely(!rtc))
 667                 return IRQ_HANDLED;
 668
 669         rtc_lock(rtc->dev);
 670
 671         /* Ctrlb holds the interrupt-enable bits and ctrlc the flag bits. */
 672         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 673         ctrlc = rtc->read(rtc, RTC_CTRL_C);
 674
 675         /* Is the IRQF bit set? */
 676         if (likely(ctrlc & RTC_CTRL_C_IRQF)) {
 677                 /*
 678                  * We need to determine if it was one of the standard
 679                  * events: PF, AF, or UF.  If so, we handle them and
 680                  * update the RTC core.
 681                  */
 682                 if (likely(ctrlc & RTC_CTRL_B_PAU_MASK)) {
 683                         events = RTC_IRQF;
 684
 685                         /* Check for a periodic interrupt. */
 686                         if ((ctrlb & RTC_CTRL_B_PIE) &&
 687                             (ctrlc & RTC_CTRL_C_PF)) {
 688                                 events |= RTC_PF;
 689                                 num_irqs++;
 690                         }
 691
 692                         /* Check for an alarm interrupt. */
 693                         if ((ctrlb & RTC_CTRL_B_AIE) &&
 694                             (ctrlc & RTC_CTRL_C_AF)) {
 695                                 events |= RTC_AF;
 696                                 num_irqs++;
 697                         }
 698
 699                         /* Check for an update interrupt. */
 700                         if ((ctrlb & RTC_CTRL_B_UIE) &&
 701                             (ctrlc & RTC_CTRL_C_UF)) {
 702                                 events |= RTC_UF;
 703                                 num_irqs++;
 704                         }
 705                 } else {
 706                         /*
 707                          * One of the "extended" interrupts was received that
 708                          * is not recognized by the RTC core.
 709                          */
 710                         ds1685_rtc_extended_irq(rtc, pdev);
 711                 }
 712         }
 713         rtc_update_irq(rtc->dev, num_irqs, events);
 714         rtc_unlock(rtc->dev);
 715
 716         return events ? IRQ_HANDLED : IRQ_NONE;
 717 }
 718 /* ----------------------------------------------------------------------- */
 719
 720
 721 /* ----------------------------------------------------------------------- */
 722 /* ProcFS interface */
 723
 724 #ifdef CONFIG_PROC_FS
 725 #define NUM_REGS        6       /* Num of control registers. */
 726 #define NUM_BITS        8       /* Num bits per register. */
 727 #define NUM_SPACES      4       /* Num spaces between each bit. */
 728
 729 /*
 730  * Periodic Interrupt Rates.
 731  */
 732 static const char *ds1685_rtc_pirq_rate[16] = {
 733         "none", "3.90625ms", "7.8125ms", "0.122070ms", "0.244141ms",
 734         "0.488281ms", "0.9765625ms", "1.953125ms", "3.90625ms", "7.8125ms",
 735         "15.625ms", "31.25ms", "62.5ms", "125ms", "250ms", "500ms"
 736 };
 737
 738 /*
 739  * Square-Wave Output Frequencies.
 740  */
 741 static const char *ds1685_rtc_sqw_freq[16] = {
 742         "none", "256Hz", "128Hz", "8192Hz", "4096Hz", "2048Hz", "1024Hz",
 743         "512Hz", "256Hz", "128Hz", "64Hz", "32Hz", "16Hz", "8Hz", "4Hz", "2Hz"
 744 };
 745
 746 /**
 747  * ds1685_rtc_proc - procfs access function.
 748  * @dev: pointer to device structure.
 749  * @seq: pointer to seq_file structure.
 750  */
 751 static int
 752 ds1685_rtc_proc(struct device *dev, struct seq_file *seq)
 753 {
 754         struct ds1685_priv *rtc = dev_get_drvdata(dev);
 755         u8 ctrla, ctrlb, ctrld, ctrl4a, ctrl4b, ssn[8];
 756         char *model;
 757
 758         /* Read all the relevant data from the control registers. */
 759         ds1685_rtc_switch_to_bank1(rtc);
 760         ds1685_rtc_get_ssn(rtc, ssn);
 761         ctrla = rtc->read(rtc, RTC_CTRL_A);
 762         ctrlb = rtc->read(rtc, RTC_CTRL_B);
 763         ctrld = rtc->read(rtc, RTC_CTRL_D);
 764         ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
 765         ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
 766         ds1685_rtc_switch_to_bank0(rtc);
 767
 768         /* Determine the RTC model. */
 769         switch (ssn[0]) {
 770         case RTC_MODEL_DS1685:
 771                 model = "DS1685/DS1687\0";
 772                 break;
 773         case RTC_MODEL_DS1689:
 774                 model = "DS1689/DS1693\0";
 775                 break;
 776         case RTC_MODEL_DS17285:
 777                 model = "DS17285/DS17287\0";
 778                 break;
 779         case RTC_MODEL_DS17485:
 780                 model = "DS17485/DS17487\0";
 781                 break;
 782         case RTC_MODEL_DS17885:
 783                 model = "DS17885/DS17887\0";
 784                 break;
 785         default:
 786                 model = "Unknown\0";
 787                 break;
 788         }
 789
 790         /* Print out the information. */
 791         seq_printf(seq,
 792            "Model\t\t: %s\n"
 793            "Oscillator\t: %s\n"
 794            "12/24hr\t\t: %s\n"
 795            "DST\t\t: %s\n"
 796            "Data mode\t: %s\n"
 797            "Battery\t\t: %s\n"
 798            "Aux batt\t: %s\n"
 799            "Update IRQ\t: %s\n"
 800            "Periodic IRQ\t: %s\n"
 801            "Periodic Rate\t: %s\n"
 802            "SQW Freq\t: %s\n"
 803            "Serial #\t: %8phC\n",
 804            model,
 805            ((ctrla & RTC_CTRL_A_DV1) ? "enabled" : "disabled"),
 806            ((ctrlb & RTC_CTRL_B_2412) ? "24-hour" : "12-hour"),
 807            ((ctrlb & RTC_CTRL_B_DSE) ? "enabled" : "disabled"),
 808            ((ctrlb & RTC_CTRL_B_DM) ? "binary" : "BCD"),
 809            ((ctrld & RTC_CTRL_D_VRT) ? "ok" : "exhausted or n/a"),
 810            ((ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "exhausted or n/a"),
 811            ((ctrlb & RTC_CTRL_B_UIE) ? "yes" : "no"),
 812            ((ctrlb & RTC_CTRL_B_PIE) ? "yes" : "no"),
 813            (!(ctrl4b & RTC_CTRL_4B_E32K) ?
 814             ds1685_rtc_pirq_rate[(ctrla & RTC_CTRL_A_RS_MASK)] : "none"),
 815            (!((ctrl4b & RTC_CTRL_4B_E32K)) ?
 816             ds1685_rtc_sqw_freq[(ctrla & RTC_CTRL_A_RS_MASK)] : "32768Hz"),
 817            ssn);
 818         return 0;
 819 }
 820 #else
 821 #define ds1685_rtc_proc NULL
 822 #endif /* CONFIG_PROC_FS */
 823 /* ----------------------------------------------------------------------- */
 824
 825
 826 /* ----------------------------------------------------------------------- */
 827 /* RTC Class operations */
 828
 829 static const struct rtc_class_ops
 830 ds1685_rtc_ops = {
 831         .proc = ds1685_rtc_proc,
 832         .read_time = ds1685_rtc_read_time,
 833         .set_time = ds1685_rtc_set_time,
 834         .read_alarm = ds1685_rtc_read_alarm,
 835         .set_alarm = ds1685_rtc_set_alarm,
 836         .alarm_irq_enable = ds1685_rtc_alarm_irq_enable,
 837 };
 838 /* ----------------------------------------------------------------------- */
 839
 840 static int ds1685_nvram_read(void *priv, unsigned int pos, void *val,
 841                              size_t size)
 842 {
 843         struct ds1685_priv *rtc = priv;
 844         struct mutex *rtc_mutex = &rtc->dev->ops_lock;
 845         ssize_t count;
 846         u8 *buf = val;
 847         int err;
 848
 849         err = mutex_lock_interruptible(rtc_mutex);
 850         if (err)
 851                 return err;
 852
 853         ds1685_rtc_switch_to_bank0(rtc);
 854
 855         /* Read NVRAM in time and bank0 registers. */
 856         for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
 857              count++, size--) {
 858                 if (count < NVRAM_SZ_TIME)
 859                         *buf++ = rtc->read(rtc, (NVRAM_TIME_BASE + pos++));
 860                 else
 861                         *buf++ = rtc->read(rtc, (NVRAM_BANK0_BASE + pos++));
 862         }
 863
 864 #ifndef CONFIG_RTC_DRV_DS1689
 865         if (size > 0) {
 866                 ds1685_rtc_switch_to_bank1(rtc);
 867
 868 #ifndef CONFIG_RTC_DRV_DS1685
 869                 /* Enable 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
 874                 /* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
 875                  * reading with burst-mode */
 876                 rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
 877                            (pos - NVRAM_TOTAL_SZ_BANK0));
 878 #endif
 879
 880                 /* Read NVRAM in bank1 registers. */
 881                 for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
 882                      count++, size--) {
 883 #ifdef CONFIG_RTC_DRV_DS1685
 884                         /* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
 885                          * before each read. */
 886                         rtc->write(rtc, RTC_BANK1_RAM_ADDR,
 887                                    (pos - NVRAM_TOTAL_SZ_BANK0));
 888 #endif
 889                         *buf++ = rtc->read(rtc, RTC_BANK1_RAM_DATA_PORT);
 890                         pos++;
 891                 }
 892
 893 #ifndef CONFIG_RTC_DRV_DS1685
 894                 /* Disable burst-mode on DS17x85/DS17x87 */
 895                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 896                            (rtc->read(rtc, RTC_EXT_CTRL_4A) &
 897                             ~(RTC_CTRL_4A_BME)));
 898 #endif
 899                 ds1685_rtc_switch_to_bank0(rtc);
 900         }
 901 #endif /* !CONFIG_RTC_DRV_DS1689 */
 902         mutex_unlock(rtc_mutex);
 903
 904         return 0;
 905 }
 906
 907 static int ds1685_nvram_write(void *priv, unsigned int pos, void *val,
 908                               size_t size)
 909 {
 910         struct ds1685_priv *rtc = priv;
 911         struct mutex *rtc_mutex = &rtc->dev->ops_lock;
 912         ssize_t count;
 913         u8 *buf = val;
 914         int err;
 915
 916         err = mutex_lock_interruptible(rtc_mutex);
 917         if (err)
 918                 return err;
 919
 920         ds1685_rtc_switch_to_bank0(rtc);
 921
 922         /* Write NVRAM in time and bank0 registers. */
 923         for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ_BANK0;
 924              count++, size--)
 925                 if (count < NVRAM_SZ_TIME)
 926                         rtc->write(rtc, (NVRAM_TIME_BASE + pos++),
 927                                    *buf++);
 928                 else
 929                         rtc->write(rtc, (NVRAM_BANK0_BASE), *buf++);
 930
 931 #ifndef CONFIG_RTC_DRV_DS1689
 932         if (size > 0) {
 933                 ds1685_rtc_switch_to_bank1(rtc);
 934
 935 #ifndef CONFIG_RTC_DRV_DS1685
 936                 /* Enable 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
 941                 /* We need one write to RTC_BANK1_RAM_ADDR_LSB to start
 942                  * writing with burst-mode */
 943                 rtc->write(rtc, RTC_BANK1_RAM_ADDR_LSB,
 944                            (pos - NVRAM_TOTAL_SZ_BANK0));
 945 #endif
 946
 947                 /* Write NVRAM in bank1 registers. */
 948                 for (count = 0; size > 0 && pos < NVRAM_TOTAL_SZ;
 949                      count++, size--) {
 950 #ifdef CONFIG_RTC_DRV_DS1685
 951                         /* DS1685/DS1687 has to write to RTC_BANK1_RAM_ADDR
 952                          * before each read. */
 953                         rtc->write(rtc, RTC_BANK1_RAM_ADDR,
 954                                    (pos - NVRAM_TOTAL_SZ_BANK0));
 955 #endif
 956                         rtc->write(rtc, RTC_BANK1_RAM_DATA_PORT, *buf++);
 957                         pos++;
 958                 }
 959
 960 #ifndef CONFIG_RTC_DRV_DS1685
 961                 /* Disable burst-mode on DS17x85/DS17x87 */
 962                 rtc->write(rtc, RTC_EXT_CTRL_4A,
 963                            (rtc->read(rtc, RTC_EXT_CTRL_4A) &
 964                             ~(RTC_CTRL_4A_BME)));
 965 #endif
 966                 ds1685_rtc_switch_to_bank0(rtc);
 967         }
 968 #endif /* !CONFIG_RTC_DRV_DS1689 */
 969         mutex_unlock(rtc_mutex);
 970
 971         return 0;
 972 }
 973
 974 /* ----------------------------------------------------------------------- */
 975 /* SysFS interface */
 976
 977 /**
 978  * ds1685_rtc_sysfs_battery_show - sysfs file for main battery status.
 979  * @dev: pointer to device structure.
 980  * @attr: pointer to device_attribute structure.
 981  * @buf: pointer to char array to hold the output.
 982  */
 983 static ssize_t
 984 ds1685_rtc_sysfs_battery_show(struct device *dev,
 985                               struct device_attribute *attr, char *buf)
 986 {
 987         struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
 988         u8 ctrld;
 989
 990         ctrld = rtc->read(rtc, RTC_CTRL_D);
 991
 992         return sprintf(buf, "%s\n",
 993                         (ctrld & RTC_CTRL_D_VRT) ? "ok" : "not ok or N/A");
 994 }
 995 static DEVICE_ATTR(battery, S_IRUGO, ds1685_rtc_sysfs_battery_show, NULL);
 996
 997 /**
 998  * ds1685_rtc_sysfs_auxbatt_show - sysfs file for aux battery status.
 999  * @dev: pointer to device structure.
1000  * @attr: pointer to device_attribute structure.
1001  * @buf: pointer to char array to hold the output.
1002  */
1003 static ssize_t
1004 ds1685_rtc_sysfs_auxbatt_show(struct device *dev,
1005                               struct device_attribute *attr, char *buf)
1006 {
1007         struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
1008         u8 ctrl4a;
1009
1010         ds1685_rtc_switch_to_bank1(rtc);
1011         ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
1012         ds1685_rtc_switch_to_bank0(rtc);
1013
1014         return sprintf(buf, "%s\n",
1015                         (ctrl4a & RTC_CTRL_4A_VRT2) ? "ok" : "not ok or N/A");
1016 }
1017 static DEVICE_ATTR(auxbatt, S_IRUGO, ds1685_rtc_sysfs_auxbatt_show, NULL);
1018
1019 /**
1020  * ds1685_rtc_sysfs_serial_show - sysfs file for silicon serial number.
1021  * @dev: pointer to device structure.
1022  * @attr: pointer to device_attribute structure.
1023  * @buf: pointer to char array to hold the output.
1024  */
1025 static ssize_t
1026 ds1685_rtc_sysfs_serial_show(struct device *dev,
1027                              struct device_attribute *attr, char *buf)
1028 {
1029         struct ds1685_priv *rtc = dev_get_drvdata(dev->parent);
1030         u8 ssn[8];
1031
1032         ds1685_rtc_switch_to_bank1(rtc);
1033         ds1685_rtc_get_ssn(rtc, ssn);
1034         ds1685_rtc_switch_to_bank0(rtc);
1035
1036         return sprintf(buf, "%8phC\n", ssn);
1037 }
1038 static DEVICE_ATTR(serial, S_IRUGO, ds1685_rtc_sysfs_serial_show, NULL);
1039
1040 /*
1041  * struct ds1685_rtc_sysfs_misc_attrs - list for misc RTC features.
1042  */
1043 static struct attribute*
1044 ds1685_rtc_sysfs_misc_attrs[] = {
1045         &dev_attr_battery.attr,
1046         &dev_attr_auxbatt.attr,
1047         &dev_attr_serial.attr,
1048         NULL,
1049 };
1050
1051 /*
1052  * struct ds1685_rtc_sysfs_misc_grp - attr group for misc RTC features.
1053  */
1054 static const struct attribute_group
1055 ds1685_rtc_sysfs_misc_grp = {
1056         .name = "misc",
1057         .attrs = ds1685_rtc_sysfs_misc_attrs,
1058 };
1059
1060 /* ----------------------------------------------------------------------- */
1061 /* Driver Probe/Removal */
1062
1063 /**
1064  * ds1685_rtc_probe - initializes rtc driver.
1065  * @pdev: pointer to platform_device structure.
1066  */
1067 static int
1068 ds1685_rtc_probe(struct platform_device *pdev)
1069 {
1070         struct rtc_device *rtc_dev;
1071         struct ds1685_priv *rtc;
1072         struct ds1685_rtc_platform_data *pdata;
1073         u8 ctrla, ctrlb, hours;
1074         unsigned char am_pm;
1075         int ret = 0;
1076         struct nvmem_config nvmem_cfg = {
1077                 .name = "ds1685_nvram",
1078                 .size = NVRAM_TOTAL_SZ,
1079                 .reg_read = ds1685_nvram_read,
1080                 .reg_write = ds1685_nvram_write,
1081         };
1082
1083         /* Get the platform data. */
1084         pdata = (struct ds1685_rtc_platform_data *) pdev->dev.platform_data;
1085         if (!pdata)
1086                 return -ENODEV;
1087
1088         /* Allocate memory for the rtc device. */
1089         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
1090         if (!rtc)
1091                 return -ENOMEM;
1092
1093         /* Setup resources and access functions */
1094         switch (pdata->access_type) {
1095         case ds1685_reg_direct:
1096                 rtc->regs = devm_platform_ioremap_resource(pdev, 0);
1097                 if (IS_ERR(rtc->regs))
1098                         return PTR_ERR(rtc->regs);
1099                 rtc->read = ds1685_read;
1100                 rtc->write = ds1685_write;
1101                 break;
1102         case ds1685_reg_indirect:
1103                 rtc->regs = devm_platform_ioremap_resource(pdev, 0);
1104                 if (IS_ERR(rtc->regs))
1105                         return PTR_ERR(rtc->regs);
1106                 rtc->data = devm_platform_ioremap_resource(pdev, 1);
1107                 if (IS_ERR(rtc->data))
1108                         return PTR_ERR(rtc->data);
1109                 rtc->read = ds1685_indirect_read;
1110                 rtc->write = ds1685_indirect_write;
1111                 break;
1112         }
1113
1114         if (!rtc->read || !rtc->write)
1115                 return -ENXIO;
1116
1117         /* Get the register step size. */
1118         if (pdata->regstep > 0)
1119                 rtc->regstep = pdata->regstep;
1120         else
1121                 rtc->regstep = 1;
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
1278         rtc->dev = rtc_dev;
1279
1280         /*
1281          * Fetch the IRQ and setup the interrupt handler.
1282          *
1283          * Not all platforms have the IRQF pin tied to something.  If not, the
1284          * RTC will still set the *IE / *F flags and raise IRQF in ctrlc, but
1285          * there won't be an automatic way of notifying the kernel about it,
1286          * unless ctrlc is explicitly polled.
1287          */
1288         if (!pdata->no_irq) {
1289                 ret = platform_get_irq(pdev, 0);
1290                 if (ret <= 0)
1291                         return ret;
1292
1293                 rtc->irq_num = ret;
1294
1295                 /* Request an IRQ. */
1296                 ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_num,
1297                                        NULL, ds1685_rtc_irq_handler,
1298                                        IRQF_SHARED | IRQF_ONESHOT,
1299                                        pdev->name, pdev);
1300
1301                 /* Check to see if something came back. */
1302                 if (unlikely(ret)) {
1303                         dev_warn(&pdev->dev,
1304                                  "RTC interrupt not available\n");
1305                         rtc->irq_num = 0;
1306                 }
1307         }
1308         rtc->no_irq = pdata->no_irq;
1309
1310         /* Setup complete. */
1311         ds1685_rtc_switch_to_bank0(rtc);
1312
1313         ret = rtc_add_group(rtc_dev, &ds1685_rtc_sysfs_misc_grp);
1314         if (ret)
1315                 return ret;
1316
1317         nvmem_cfg.priv = rtc;
1318         ret = devm_rtc_nvmem_register(rtc_dev, &nvmem_cfg);
1319         if (ret)
1320                 return ret;
1321
1322         return devm_rtc_register_device(rtc_dev);
1323 }
1324
1325 /**
1326  * ds1685_rtc_remove - removes rtc driver.
1327  * @pdev: pointer to platform_device structure.
1328  */
1329 static int
1330 ds1685_rtc_remove(struct platform_device *pdev)
1331 {
1332         struct ds1685_priv *rtc = platform_get_drvdata(pdev);
1333
1334         /* Read Ctrl B and clear PIE/AIE/UIE. */
1335         rtc->write(rtc, RTC_CTRL_B,
1336                    (rtc->read(rtc, RTC_CTRL_B) &
1337                     ~(RTC_CTRL_B_PAU_MASK)));
1338
1339         /* Reading Ctrl C auto-clears PF/AF/UF. */
1340         rtc->read(rtc, RTC_CTRL_C);
1341
1342         /* Read Ctrl 4B and clear RIE/WIE/KSE. */
1343         rtc->write(rtc, RTC_EXT_CTRL_4B,
1344                    (rtc->read(rtc, RTC_EXT_CTRL_4B) &
1345                     ~(RTC_CTRL_4B_RWK_MASK)));
1346
1347         /* Manually clear RF/WF/KF in Ctrl 4A. */
1348         rtc->write(rtc, RTC_EXT_CTRL_4A,
1349                    (rtc->read(rtc, RTC_EXT_CTRL_4A) &
1350                     ~(RTC_CTRL_4A_RWK_MASK)));
1351
1352         return 0;
1353 }
1354
1355 /*
1356  * ds1685_rtc_driver - rtc driver properties.
1357  */
1358 static struct platform_driver ds1685_rtc_driver = {
1359         .driver         = {
1360                 .name   = "rtc-ds1685",
1361         },
1362         .probe          = ds1685_rtc_probe,
1363         .remove         = ds1685_rtc_remove,
1364 };
1365 module_platform_driver(ds1685_rtc_driver);
1366 /* ----------------------------------------------------------------------- */
1367
1368
1369 /* ----------------------------------------------------------------------- */
1370 /* Poweroff function */
1371
1372 /**
1373  * ds1685_rtc_poweroff - uses the RTC chip to power the system off.
1374  * @pdev: pointer to platform_device structure.
1375  */
1376 void __noreturn
1377 ds1685_rtc_poweroff(struct platform_device *pdev)
1378 {
1379         u8 ctrla, ctrl4a, ctrl4b;
1380         struct ds1685_priv *rtc;
1381
1382         /* Check for valid RTC data, else, spin forever. */
1383         if (unlikely(!pdev)) {
1384                 pr_emerg("platform device data not available, spinning forever ...\n");
1385                 while(1);
1386                 unreachable();
1387         } else {
1388                 /* Get the rtc data. */
1389                 rtc = platform_get_drvdata(pdev);
1390
1391                 /*
1392                  * Disable our IRQ.  We're powering down, so we're not
1393                  * going to worry about cleaning up.  Most of that should
1394                  * have been taken care of by the shutdown scripts and this
1395                  * is the final function call.
1396                  */
1397                 if (!rtc->no_irq)
1398                         disable_irq_nosync(rtc->irq_num);
1399
1400                 /* Oscillator must be on and the countdown chain enabled. */
1401                 ctrla = rtc->read(rtc, RTC_CTRL_A);
1402                 ctrla |= RTC_CTRL_A_DV1;
1403                 ctrla &= ~(RTC_CTRL_A_DV2);
1404                 rtc->write(rtc, RTC_CTRL_A, ctrla);
1405
1406                 /*
1407                  * Read Control 4A and check the status of the auxillary
1408                  * battery.  This must be present and working (VRT2 = 1)
1409                  * for wakeup and kickstart functionality to be useful.
1410                  */
1411                 ds1685_rtc_switch_to_bank1(rtc);
1412                 ctrl4a = rtc->read(rtc, RTC_EXT_CTRL_4A);
1413                 if (ctrl4a & RTC_CTRL_4A_VRT2) {
1414                         /* Clear all of the interrupt flags on Control 4A. */
1415                         ctrl4a &= ~(RTC_CTRL_4A_RWK_MASK);
1416                         rtc->write(rtc, RTC_EXT_CTRL_4A, ctrl4a);
1417
1418                         /*
1419                          * The auxillary battery is present and working.
1420                          * Enable extended functions (ABE=1), enable
1421                          * wake-up (WIE=1), and enable kickstart (KSE=1)
1422                          * in Control 4B.
1423                          */
1424                         ctrl4b = rtc->read(rtc, RTC_EXT_CTRL_4B);
1425                         ctrl4b |= (RTC_CTRL_4B_ABE | RTC_CTRL_4B_WIE |
1426                                    RTC_CTRL_4B_KSE);
1427                         rtc->write(rtc, RTC_EXT_CTRL_4B, ctrl4b);
1428                 }
1429
1430                 /* Set PAB to 1 in Control 4A to power the system down. */
1431                 dev_warn(&pdev->dev, "Powerdown.\n");
1432                 msleep(20);
1433                 rtc->write(rtc, RTC_EXT_CTRL_4A,
1434                            (ctrl4a | RTC_CTRL_4A_PAB));
1435
1436                 /* Spin ... we do not switch back to bank0. */
1437                 while(1);
1438                 unreachable();
1439         }
1440 }
1441 EXPORT_SYMBOL(ds1685_rtc_poweroff);
1442 /* ----------------------------------------------------------------------- */
1443
1444
1445 MODULE_AUTHOR("Joshua Kinard <kumba@gentoo.org>");
1446 MODULE_AUTHOR("Matthias Fuchs <matthias.fuchs@esd-electronics.com>");
1447 MODULE_DESCRIPTION("Dallas/Maxim DS1685/DS1687-series RTC driver");
1448 MODULE_LICENSE("GPL");
1449 MODULE_ALIAS("platform:rtc-ds1685");