drivers/rtc/rtc-ds1307.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
   4  *
   5  *  Copyright (C) 2005 James Chapman (ds1337 core)
   6  *  Copyright (C) 2006 David Brownell
   7  *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)
   8  *  Copyright (C) 2012 Bertrand Achard (nvram access fixes)
   9  */
  10
  11 #include <linux/bcd.h>
  12 #include <linux/i2c.h>
  13 #include <linux/init.h>
  14 #include <linux/kstrtox.h>
  15 #include <linux/mod_devicetable.h>
  16 #include <linux/module.h>
  17 #include <linux/property.h>
  18 #include <linux/rtc/ds1307.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21 #include <linux/string.h>
  22 #include <linux/hwmon.h>
  23 #include <linux/hwmon-sysfs.h>
  24 #include <linux/clk-provider.h>
  25 #include <linux/regmap.h>
  26 #include <linux/watchdog.h>
  27
  28 /*
  29  * We can't determine type by probing, but if we expect pre-Linux code
  30  * to have set the chip up as a clock (turning on the oscillator and
  31  * setting the date and time), Linux can ignore the non-clock features.
  32  * That's a natural job for a factory or repair bench.
  33  */
  34 enum ds_type {
  35         unknown_ds_type, /* always first and 0 */
  36         ds_1307,
  37         ds_1308,
  38         ds_1337,
  39         ds_1338,
  40         ds_1339,
  41         ds_1340,
  42         ds_1341,
  43         ds_1388,
  44         ds_3231,
  45         m41t0,
  46         m41t00,
  47         m41t11,
  48         mcp794xx,
  49         rx_8025,
  50         rx_8130,
  51         last_ds_type /* always last */
  52         /* rs5c372 too?  different address... */
  53 };
  54
  55 /* RTC registers don't differ much, except for the century flag */
  56 #define DS1307_REG_SECS         0x00    /* 00-59 */
  57 #       define DS1307_BIT_CH            0x80
  58 #       define DS1340_BIT_nEOSC         0x80
  59 #       define MCP794XX_BIT_ST          0x80
  60 #define DS1307_REG_MIN          0x01    /* 00-59 */
  61 #       define M41T0_BIT_OF             0x80
  62 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  63 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  64 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  65 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  66 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  67 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  68 #       define MCP794XX_BIT_VBATEN      0x08
  69 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  70 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  71 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  72 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  73
  74 /*
  75  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  76  * start at 7, and they differ a LOT. Only control and status matter for
  77  * basic RTC date and time functionality; be careful using them.
  78  */
  79 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  80 #       define DS1307_BIT_OUT           0x80
  81 #       define DS1338_BIT_OSF           0x20
  82 #       define DS1307_BIT_SQWE          0x10
  83 #       define DS1307_BIT_RS1           0x02
  84 #       define DS1307_BIT_RS0           0x01
  85 #define DS1337_REG_CONTROL      0x0e
  86 #       define DS1337_BIT_nEOSC         0x80
  87 #       define DS1339_BIT_BBSQI         0x20
  88 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  89 #       define DS1337_BIT_RS2           0x10
  90 #       define DS1337_BIT_RS1           0x08
  91 #       define DS1337_BIT_INTCN         0x04
  92 #       define DS1337_BIT_A2IE          0x02
  93 #       define DS1337_BIT_A1IE          0x01
  94 #define DS1340_REG_CONTROL      0x07
  95 #       define DS1340_BIT_OUT           0x80
  96 #       define DS1340_BIT_FT            0x40
  97 #       define DS1340_BIT_CALIB_SIGN    0x20
  98 #       define DS1340_M_CALIBRATION     0x1f
  99 #define DS1340_REG_FLAG         0x09
 100 #       define DS1340_BIT_OSF           0x80
 101 #define DS1337_REG_STATUS       0x0f
 102 #       define DS1337_BIT_OSF           0x80
 103 #       define DS3231_BIT_EN32KHZ       0x08
 104 #       define DS1337_BIT_A2I           0x02
 105 #       define DS1337_BIT_A1I           0x01
 106 #define DS1339_REG_ALARM1_SECS  0x07
 107
 108 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
 109
 110 #define RX8025_REG_CTRL1        0x0e
 111 #       define RX8025_BIT_2412          0x20
 112 #define RX8025_REG_CTRL2        0x0f
 113 #       define RX8025_BIT_PON           0x10
 114 #       define RX8025_BIT_VDET          0x40
 115 #       define RX8025_BIT_XST           0x20
 116
 117 #define RX8130_REG_ALARM_MIN            0x17
 118 #define RX8130_REG_ALARM_HOUR           0x18
 119 #define RX8130_REG_ALARM_WEEK_OR_DAY    0x19
 120 #define RX8130_REG_EXTENSION            0x1c
 121 #define RX8130_REG_EXTENSION_WADA       BIT(3)
 122 #define RX8130_REG_FLAG                 0x1d
 123 #define RX8130_REG_FLAG_VLF             BIT(1)
 124 #define RX8130_REG_FLAG_AF              BIT(3)
 125 #define RX8130_REG_CONTROL0             0x1e
 126 #define RX8130_REG_CONTROL0_AIE         BIT(3)
 127 #define RX8130_REG_CONTROL1             0x1f
 128 #define RX8130_REG_CONTROL1_INIEN       BIT(4)
 129 #define RX8130_REG_CONTROL1_CHGEN       BIT(5)
 130
 131 #define MCP794XX_REG_CONTROL            0x07
 132 #       define MCP794XX_BIT_ALM0_EN     0x10
 133 #       define MCP794XX_BIT_ALM1_EN     0x20
 134 #define MCP794XX_REG_ALARM0_BASE        0x0a
 135 #define MCP794XX_REG_ALARM0_CTRL        0x0d
 136 #define MCP794XX_REG_ALARM1_BASE        0x11
 137 #define MCP794XX_REG_ALARM1_CTRL        0x14
 138 #       define MCP794XX_BIT_ALMX_IF     BIT(3)
 139 #       define MCP794XX_BIT_ALMX_C0     BIT(4)
 140 #       define MCP794XX_BIT_ALMX_C1     BIT(5)
 141 #       define MCP794XX_BIT_ALMX_C2     BIT(6)
 142 #       define MCP794XX_BIT_ALMX_POL    BIT(7)
 143 #       define MCP794XX_MSK_ALMX_MATCH  (MCP794XX_BIT_ALMX_C0 | \
 144                                          MCP794XX_BIT_ALMX_C1 | \
 145                                          MCP794XX_BIT_ALMX_C2)
 146
 147 #define M41TXX_REG_CONTROL      0x07
 148 #       define M41TXX_BIT_OUT           BIT(7)
 149 #       define M41TXX_BIT_FT            BIT(6)
 150 #       define M41TXX_BIT_CALIB_SIGN    BIT(5)
 151 #       define M41TXX_M_CALIBRATION     GENMASK(4, 0)
 152
 153 #define DS1388_REG_WDOG_HUN_SECS        0x08
 154 #define DS1388_REG_WDOG_SECS            0x09
 155 #define DS1388_REG_FLAG                 0x0b
 156 #       define DS1388_BIT_WF            BIT(6)
 157 #       define DS1388_BIT_OSF           BIT(7)
 158 #define DS1388_REG_CONTROL              0x0c
 159 #       define DS1388_BIT_RST           BIT(0)
 160 #       define DS1388_BIT_WDE           BIT(1)
 161 #       define DS1388_BIT_nEOSC         BIT(7)
 162
 163 /* negative offset step is -2.034ppm */
 164 #define M41TXX_NEG_OFFSET_STEP_PPB      2034
 165 /* positive offset step is +4.068ppm */
 166 #define M41TXX_POS_OFFSET_STEP_PPB      4068
 167 /* Min and max values supported with 'offset' interface by M41TXX */
 168 #define M41TXX_MIN_OFFSET       ((-31) * M41TXX_NEG_OFFSET_STEP_PPB)
 169 #define M41TXX_MAX_OFFSET       ((31) * M41TXX_POS_OFFSET_STEP_PPB)
 170
 171 struct ds1307 {
 172         enum ds_type            type;
 173         struct device           *dev;
 174         struct regmap           *regmap;
 175         const char              *name;
 176         struct rtc_device       *rtc;
 177 #ifdef CONFIG_COMMON_CLK
 178         struct clk_hw           clks[2];
 179 #endif
 180 };
 181
 182 struct chip_desc {
 183         unsigned                alarm:1;
 184         u16                     nvram_offset;
 185         u16                     nvram_size;
 186         u8                      offset; /* register's offset */
 187         u8                      century_reg;
 188         u8                      century_enable_bit;
 189         u8                      century_bit;
 190         u8                      bbsqi_bit;
 191         irq_handler_t           irq_handler;
 192         const struct rtc_class_ops *rtc_ops;
 193         u16                     trickle_charger_reg;
 194         u8                      (*do_trickle_setup)(struct ds1307 *, u32,
 195                                                     bool);
 196         /* Does the RTC require trickle-resistor-ohms to select the value of
 197          * the resistor between Vcc and Vbackup?
 198          */
 199         bool                    requires_trickle_resistor;
 200         /* Some RTC's batteries and supercaps were charged by default, others
 201          * allow charging but were not configured previously to do so.
 202          * Remember this behavior to stay backwards compatible.
 203          */
 204         bool                    charge_default;
 205 };
 206
 207 static const struct chip_desc chips[last_ds_type];
 208
 209 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 210 {
 211         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 212         int             tmp, ret;
 213         const struct chip_desc *chip = &chips[ds1307->type];
 214         u8 regs[7];
 215
 216         if (ds1307->type == rx_8130) {
 217                 unsigned int regflag;
 218                 ret = regmap_read(ds1307->regmap, RX8130_REG_FLAG, &regflag);
 219                 if (ret) {
 220                         dev_err(dev, "%s error %d\n", "read", ret);
 221                         return ret;
 222                 }
 223
 224                 if (regflag & RX8130_REG_FLAG_VLF) {
 225                         dev_warn_once(dev, "oscillator failed, set time!\n");
 226                         return -EINVAL;
 227                 }
 228         }
 229
 230         /* read the RTC date and time registers all at once */
 231         ret = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
 232                                sizeof(regs));
 233         if (ret) {
 234                 dev_err(dev, "%s error %d\n", "read", ret);
 235                 return ret;
 236         }
 237
 238         dev_dbg(dev, "%s: %7ph\n", "read", regs);
 239
 240         /* if oscillator fail bit is set, no data can be trusted */
 241         if (ds1307->type == m41t0 &&
 242             regs[DS1307_REG_MIN] & M41T0_BIT_OF) {
 243                 dev_warn_once(dev, "oscillator failed, set time!\n");
 244                 return -EINVAL;
 245         }
 246
 247         tmp = regs[DS1307_REG_SECS];
 248         switch (ds1307->type) {
 249         case ds_1307:
 250         case m41t0:
 251         case m41t00:
 252         case m41t11:
 253                 if (tmp & DS1307_BIT_CH)
 254                         return -EINVAL;
 255                 break;
 256         case ds_1308:
 257         case ds_1338:
 258                 if (tmp & DS1307_BIT_CH)
 259                         return -EINVAL;
 260
 261                 ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &tmp);
 262                 if (ret)
 263                         return ret;
 264                 if (tmp & DS1338_BIT_OSF)
 265                         return -EINVAL;
 266                 break;
 267         case ds_1340:
 268                 if (tmp & DS1340_BIT_nEOSC)
 269                         return -EINVAL;
 270
 271                 ret = regmap_read(ds1307->regmap, DS1340_REG_FLAG, &tmp);
 272                 if (ret)
 273                         return ret;
 274                 if (tmp & DS1340_BIT_OSF)
 275                         return -EINVAL;
 276                 break;
 277         case ds_1388:
 278                 ret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &tmp);
 279                 if (ret)
 280                         return ret;
 281                 if (tmp & DS1388_BIT_OSF)
 282                         return -EINVAL;
 283                 break;
 284         case mcp794xx:
 285                 if (!(tmp & MCP794XX_BIT_ST))
 286                         return -EINVAL;
 287
 288                 break;
 289         default:
 290                 break;
 291         }
 292
 293         t->tm_sec = bcd2bin(regs[DS1307_REG_SECS] & 0x7f);
 294         t->tm_min = bcd2bin(regs[DS1307_REG_MIN] & 0x7f);
 295         tmp = regs[DS1307_REG_HOUR] & 0x3f;
 296         t->tm_hour = bcd2bin(tmp);
 297         /* rx8130 is bit position, not BCD */
 298         if (ds1307->type == rx_8130)
 299                 t->tm_wday = fls(regs[DS1307_REG_WDAY] & 0x7f);
 300         else
 301                 t->tm_wday = bcd2bin(regs[DS1307_REG_WDAY] & 0x07) - 1;
 302         t->tm_mday = bcd2bin(regs[DS1307_REG_MDAY] & 0x3f);
 303         tmp = regs[DS1307_REG_MONTH] & 0x1f;
 304         t->tm_mon = bcd2bin(tmp) - 1;
 305         t->tm_year = bcd2bin(regs[DS1307_REG_YEAR]) + 100;
 306
 307         if (regs[chip->century_reg] & chip->century_bit &&
 308             IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
 309                 t->tm_year += 100;
 310
 311         dev_dbg(dev, "%s secs=%d, mins=%d, "
 312                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 313                 "read", t->tm_sec, t->tm_min,
 314                 t->tm_hour, t->tm_mday,
 315                 t->tm_mon, t->tm_year, t->tm_wday);
 316
 317         return 0;
 318 }
 319
 320 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 321 {
 322         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 323         const struct chip_desc *chip = &chips[ds1307->type];
 324         int             result;
 325         int             tmp;
 326         u8              regs[7];
 327
 328         dev_dbg(dev, "%s secs=%d, mins=%d, "
 329                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 330                 "write", t->tm_sec, t->tm_min,
 331                 t->tm_hour, t->tm_mday,
 332                 t->tm_mon, t->tm_year, t->tm_wday);
 333
 334         if (t->tm_year < 100)
 335                 return -EINVAL;
 336
 337 #ifdef CONFIG_RTC_DRV_DS1307_CENTURY
 338         if (t->tm_year > (chip->century_bit ? 299 : 199))
 339                 return -EINVAL;
 340 #else
 341         if (t->tm_year > 199)
 342                 return -EINVAL;
 343 #endif
 344
 345         regs[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 346         regs[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 347         regs[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 348         /* rx8130 is bit position, not BCD */
 349         if (ds1307->type == rx_8130)
 350                 regs[DS1307_REG_WDAY] = 1 << t->tm_wday;
 351         else
 352                 regs[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 353         regs[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 354         regs[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 355
 356         /* assume 20YY not 19YY */
 357         tmp = t->tm_year - 100;
 358         regs[DS1307_REG_YEAR] = bin2bcd(tmp);
 359
 360         if (chip->century_enable_bit)
 361                 regs[chip->century_reg] |= chip->century_enable_bit;
 362         if (t->tm_year > 199 && chip->century_bit)
 363                 regs[chip->century_reg] |= chip->century_bit;
 364
 365         switch (ds1307->type) {
 366         case ds_1308:
 367         case ds_1338:
 368                 regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
 369                                    DS1338_BIT_OSF, 0);
 370                 break;
 371         case ds_1340:
 372                 regmap_update_bits(ds1307->regmap, DS1340_REG_FLAG,
 373                                    DS1340_BIT_OSF, 0);
 374                 break;
 375         case ds_1388:
 376                 regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
 377                                    DS1388_BIT_OSF, 0);
 378                 break;
 379         case mcp794xx:
 380                 /*
 381                  * these bits were cleared when preparing the date/time
 382                  * values and need to be set again before writing the
 383                  * regsfer out to the device.
 384                  */
 385                 regs[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
 386                 regs[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
 387                 break;
 388         default:
 389                 break;
 390         }
 391
 392         dev_dbg(dev, "%s: %7ph\n", "write", regs);
 393
 394         result = regmap_bulk_write(ds1307->regmap, chip->offset, regs,
 395                                    sizeof(regs));
 396         if (result) {
 397                 dev_err(dev, "%s error %d\n", "write", result);
 398                 return result;
 399         }
 400
 401         if (ds1307->type == rx_8130) {
 402                 /* clear Voltage Loss Flag as data is available now */
 403                 result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
 404                                       ~(u8)RX8130_REG_FLAG_VLF);
 405                 if (result) {
 406                         dev_err(dev, "%s error %d\n", "write", result);
 407                         return result;
 408                 }
 409         }
 410
 411         return 0;
 412 }
 413
 414 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 415 {
 416         struct ds1307           *ds1307 = dev_get_drvdata(dev);
 417         int                     ret;
 418         u8                      regs[9];
 419
 420         /* read all ALARM1, ALARM2, and status registers at once */
 421         ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS,
 422                                regs, sizeof(regs));
 423         if (ret) {
 424                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 425                 return ret;
 426         }
 427
 428         dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
 429                 &regs[0], &regs[4], &regs[7]);
 430
 431         /*
 432          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 433          * and that all four fields are checked matches
 434          */
 435         t->time.tm_sec = bcd2bin(regs[0] & 0x7f);
 436         t->time.tm_min = bcd2bin(regs[1] & 0x7f);
 437         t->time.tm_hour = bcd2bin(regs[2] & 0x3f);
 438         t->time.tm_mday = bcd2bin(regs[3] & 0x3f);
 439
 440         /* ... and status */
 441         t->enabled = !!(regs[7] & DS1337_BIT_A1IE);
 442         t->pending = !!(regs[8] & DS1337_BIT_A1I);
 443
 444         dev_dbg(dev, "%s secs=%d, mins=%d, "
 445                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 446                 "alarm read", t->time.tm_sec, t->time.tm_min,
 447                 t->time.tm_hour, t->time.tm_mday,
 448                 t->enabled, t->pending);
 449
 450         return 0;
 451 }
 452
 453 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 454 {
 455         struct ds1307           *ds1307 = dev_get_drvdata(dev);
 456         unsigned char           regs[9];
 457         u8                      control, status;
 458         int                     ret;
 459
 460         dev_dbg(dev, "%s secs=%d, mins=%d, "
 461                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 462                 "alarm set", t->time.tm_sec, t->time.tm_min,
 463                 t->time.tm_hour, t->time.tm_mday,
 464                 t->enabled, t->pending);
 465
 466         /* read current status of both alarms and the chip */
 467         ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
 468                                sizeof(regs));
 469         if (ret) {
 470                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 471                 return ret;
 472         }
 473         control = regs[7];
 474         status = regs[8];
 475
 476         dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
 477                 &regs[0], &regs[4], control, status);
 478
 479         /* set ALARM1, using 24 hour and day-of-month modes */
 480         regs[0] = bin2bcd(t->time.tm_sec);
 481         regs[1] = bin2bcd(t->time.tm_min);
 482         regs[2] = bin2bcd(t->time.tm_hour);
 483         regs[3] = bin2bcd(t->time.tm_mday);
 484
 485         /* set ALARM2 to non-garbage */
 486         regs[4] = 0;
 487         regs[5] = 0;
 488         regs[6] = 0;
 489
 490         /* disable alarms */
 491         regs[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 492         regs[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 493
 494         ret = regmap_bulk_write(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
 495                                 sizeof(regs));
 496         if (ret) {
 497                 dev_err(dev, "can't set alarm time\n");
 498                 return ret;
 499         }
 500
 501         /* optionally enable ALARM1 */
 502         if (t->enabled) {
 503                 dev_dbg(dev, "alarm IRQ armed\n");
 504                 regs[7] |= DS1337_BIT_A1IE;     /* only ALARM1 is used */
 505                 regmap_write(ds1307->regmap, DS1337_REG_CONTROL, regs[7]);
 506         }
 507
 508         return 0;
 509 }
 510
 511 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 512 {
 513         struct ds1307           *ds1307 = dev_get_drvdata(dev);
 514
 515         return regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
 516                                   DS1337_BIT_A1IE,
 517                                   enabled ? DS1337_BIT_A1IE : 0);
 518 }
 519
 520 static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307, u32 ohms, bool diode)
 521 {
 522         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
 523                 DS1307_TRICKLE_CHARGER_NO_DIODE;
 524
 525         setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
 526
 527         switch (ohms) {
 528         case 250:
 529                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
 530                 break;
 531         case 2000:
 532                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
 533                 break;
 534         case 4000:
 535                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
 536                 break;
 537         default:
 538                 dev_warn(ds1307->dev,
 539                          "Unsupported ohm value %u in dt\n", ohms);
 540                 return 0;
 541         }
 542         return setup;
 543 }
 544
 545 static u8 do_trickle_setup_rx8130(struct ds1307 *ds1307, u32 ohms, bool diode)
 546 {
 547         /* make sure that the backup battery is enabled */
 548         u8 setup = RX8130_REG_CONTROL1_INIEN;
 549         if (diode)
 550                 setup |= RX8130_REG_CONTROL1_CHGEN;
 551
 552         return setup;
 553 }
 554
 555 static irqreturn_t rx8130_irq(int irq, void *dev_id)
 556 {
 557         struct ds1307           *ds1307 = dev_id;
 558         u8 ctl[3];
 559         int ret;
 560
 561         rtc_lock(ds1307->rtc);
 562
 563         /* Read control registers. */
 564         ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 565                                sizeof(ctl));
 566         if (ret < 0)
 567                 goto out;
 568         if (!(ctl[1] & RX8130_REG_FLAG_AF))
 569                 goto out;
 570         ctl[1] &= ~RX8130_REG_FLAG_AF;
 571         ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 572
 573         ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 574                                 sizeof(ctl));
 575         if (ret < 0)
 576                 goto out;
 577
 578         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 579
 580 out:
 581         rtc_unlock(ds1307->rtc);
 582
 583         return IRQ_HANDLED;
 584 }
 585
 586 static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 587 {
 588         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 589         u8 ald[3], ctl[3];
 590         int ret;
 591
 592         /* Read alarm registers. */
 593         ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
 594                                sizeof(ald));
 595         if (ret < 0)
 596                 return ret;
 597
 598         /* Read control registers. */
 599         ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 600                                sizeof(ctl));
 601         if (ret < 0)
 602                 return ret;
 603
 604         t->enabled = !!(ctl[2] & RX8130_REG_CONTROL0_AIE);
 605         t->pending = !!(ctl[1] & RX8130_REG_FLAG_AF);
 606
 607         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 608         t->time.tm_sec = -1;
 609         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 610         t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
 611         t->time.tm_wday = -1;
 612         t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
 613         t->time.tm_mon = -1;
 614         t->time.tm_year = -1;
 615         t->time.tm_yday = -1;
 616         t->time.tm_isdst = -1;
 617
 618         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
 619                 __func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 620                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);
 621
 622         return 0;
 623 }
 624
 625 static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 626 {
 627         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 628         u8 ald[3], ctl[3];
 629         int ret;
 630
 631         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 632                 "enabled=%d pending=%d\n", __func__,
 633                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 634                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 635                 t->enabled, t->pending);
 636
 637         /* Read control registers. */
 638         ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 639                                sizeof(ctl));
 640         if (ret < 0)
 641                 return ret;
 642
 643         ctl[0] &= RX8130_REG_EXTENSION_WADA;
 644         ctl[1] &= ~RX8130_REG_FLAG_AF;
 645         ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 646
 647         ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 648                                 sizeof(ctl));
 649         if (ret < 0)
 650                 return ret;
 651
 652         /* Hardware alarm precision is 1 minute! */
 653         ald[0] = bin2bcd(t->time.tm_min);
 654         ald[1] = bin2bcd(t->time.tm_hour);
 655         ald[2] = bin2bcd(t->time.tm_mday);
 656
 657         ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
 658                                 sizeof(ald));
 659         if (ret < 0)
 660                 return ret;
 661
 662         if (!t->enabled)
 663                 return 0;
 664
 665         ctl[2] |= RX8130_REG_CONTROL0_AIE;
 666
 667         return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, ctl[2]);
 668 }
 669
 670 static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)
 671 {
 672         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 673         int ret, reg;
 674
 675         ret = regmap_read(ds1307->regmap, RX8130_REG_CONTROL0, &reg);
 676         if (ret < 0)
 677                 return ret;
 678
 679         if (enabled)
 680                 reg |= RX8130_REG_CONTROL0_AIE;
 681         else
 682                 reg &= ~RX8130_REG_CONTROL0_AIE;
 683
 684         return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, reg);
 685 }
 686
 687 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
 688 {
 689         struct ds1307           *ds1307 = dev_id;
 690         struct mutex            *lock = &ds1307->rtc->ops_lock;
 691         int reg, ret;
 692
 693         mutex_lock(lock);
 694
 695         /* Check and clear alarm 0 interrupt flag. */
 696         ret = regmap_read(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, &reg);
 697         if (ret)
 698                 goto out;
 699         if (!(reg & MCP794XX_BIT_ALMX_IF))
 700                 goto out;
 701         reg &= ~MCP794XX_BIT_ALMX_IF;
 702         ret = regmap_write(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, reg);
 703         if (ret)
 704                 goto out;
 705
 706         /* Disable alarm 0. */
 707         ret = regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
 708                                  MCP794XX_BIT_ALM0_EN, 0);
 709         if (ret)
 710                 goto out;
 711
 712         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 713
 714 out:
 715         mutex_unlock(lock);
 716
 717         return IRQ_HANDLED;
 718 }
 719
 720 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 721 {
 722         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 723         u8 regs[10];
 724         int ret;
 725
 726         /* Read control and alarm 0 registers. */
 727         ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 728                                sizeof(regs));
 729         if (ret)
 730                 return ret;
 731
 732         t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
 733
 734         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 735         t->time.tm_sec = bcd2bin(regs[3] & 0x7f);
 736         t->time.tm_min = bcd2bin(regs[4] & 0x7f);
 737         t->time.tm_hour = bcd2bin(regs[5] & 0x3f);
 738         t->time.tm_wday = bcd2bin(regs[6] & 0x7) - 1;
 739         t->time.tm_mday = bcd2bin(regs[7] & 0x3f);
 740         t->time.tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
 741         t->time.tm_year = -1;
 742         t->time.tm_yday = -1;
 743         t->time.tm_isdst = -1;
 744
 745         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 746                 "enabled=%d polarity=%d irq=%d match=%lu\n", __func__,
 747                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 748                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 749                 !!(regs[6] & MCP794XX_BIT_ALMX_POL),
 750                 !!(regs[6] & MCP794XX_BIT_ALMX_IF),
 751                 (regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
 752
 753         return 0;
 754 }
 755
 756 /*
 757  * We may have a random RTC weekday, therefore calculate alarm weekday based
 758  * on current weekday we read from the RTC timekeeping regs
 759  */
 760 static int mcp794xx_alm_weekday(struct device *dev, struct rtc_time *tm_alarm)
 761 {
 762         struct rtc_time tm_now;
 763         int days_now, days_alarm, ret;
 764
 765         ret = ds1307_get_time(dev, &tm_now);
 766         if (ret)
 767                 return ret;
 768
 769         days_now = div_s64(rtc_tm_to_time64(&tm_now), 24 * 60 * 60);
 770         days_alarm = div_s64(rtc_tm_to_time64(tm_alarm), 24 * 60 * 60);
 771
 772         return (tm_now.tm_wday + days_alarm - days_now) % 7 + 1;
 773 }
 774
 775 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 776 {
 777         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 778         unsigned char regs[10];
 779         int wday, ret;
 780
 781         wday = mcp794xx_alm_weekday(dev, &t->time);
 782         if (wday < 0)
 783                 return wday;
 784
 785         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 786                 "enabled=%d pending=%d\n", __func__,
 787                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 788                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 789                 t->enabled, t->pending);
 790
 791         /* Read control and alarm 0 registers. */
 792         ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 793                                sizeof(regs));
 794         if (ret)
 795                 return ret;
 796
 797         /* Set alarm 0, using 24-hour and day-of-month modes. */
 798         regs[3] = bin2bcd(t->time.tm_sec);
 799         regs[4] = bin2bcd(t->time.tm_min);
 800         regs[5] = bin2bcd(t->time.tm_hour);
 801         regs[6] = wday;
 802         regs[7] = bin2bcd(t->time.tm_mday);
 803         regs[8] = bin2bcd(t->time.tm_mon + 1);
 804
 805         /* Clear the alarm 0 interrupt flag. */
 806         regs[6] &= ~MCP794XX_BIT_ALMX_IF;
 807         /* Set alarm match: second, minute, hour, day, date, month. */
 808         regs[6] |= MCP794XX_MSK_ALMX_MATCH;
 809         /* Disable interrupt. We will not enable until completely programmed */
 810         regs[0] &= ~MCP794XX_BIT_ALM0_EN;
 811
 812         ret = regmap_bulk_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 813                                 sizeof(regs));
 814         if (ret)
 815                 return ret;
 816
 817         if (!t->enabled)
 818                 return 0;
 819         regs[0] |= MCP794XX_BIT_ALM0_EN;
 820         return regmap_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs[0]);
 821 }
 822
 823 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 824 {
 825         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 826
 827         return regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
 828                                   MCP794XX_BIT_ALM0_EN,
 829                                   enabled ? MCP794XX_BIT_ALM0_EN : 0);
 830 }
 831
 832 static int m41txx_rtc_read_offset(struct device *dev, long *offset)
 833 {
 834         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 835         unsigned int ctrl_reg;
 836         u8 val;
 837
 838         regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
 839
 840         val = ctrl_reg & M41TXX_M_CALIBRATION;
 841
 842         /* check if positive */
 843         if (ctrl_reg & M41TXX_BIT_CALIB_SIGN)
 844                 *offset = (val * M41TXX_POS_OFFSET_STEP_PPB);
 845         else
 846                 *offset = -(val * M41TXX_NEG_OFFSET_STEP_PPB);
 847
 848         return 0;
 849 }
 850
 851 static int m41txx_rtc_set_offset(struct device *dev, long offset)
 852 {
 853         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 854         unsigned int ctrl_reg;
 855
 856         if ((offset < M41TXX_MIN_OFFSET) || (offset > M41TXX_MAX_OFFSET))
 857                 return -ERANGE;
 858
 859         if (offset >= 0) {
 860                 ctrl_reg = DIV_ROUND_CLOSEST(offset,
 861                                              M41TXX_POS_OFFSET_STEP_PPB);
 862                 ctrl_reg |= M41TXX_BIT_CALIB_SIGN;
 863         } else {
 864                 ctrl_reg = DIV_ROUND_CLOSEST(abs(offset),
 865                                              M41TXX_NEG_OFFSET_STEP_PPB);
 866         }
 867
 868         return regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL,
 869                                   M41TXX_M_CALIBRATION | M41TXX_BIT_CALIB_SIGN,
 870                                   ctrl_reg);
 871 }
 872
 873 #ifdef CONFIG_WATCHDOG_CORE
 874 static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
 875 {
 876         struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 877         u8 regs[2];
 878         int ret;
 879
 880         ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
 881                                  DS1388_BIT_WF, 0);
 882         if (ret)
 883                 return ret;
 884
 885         ret = regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 886                                  DS1388_BIT_WDE | DS1388_BIT_RST, 0);
 887         if (ret)
 888                 return ret;
 889
 890         /*
 891          * watchdog timeouts are measured in seconds. So ignore hundredths of
 892          * seconds field.
 893          */
 894         regs[0] = 0;
 895         regs[1] = bin2bcd(wdt_dev->timeout);
 896
 897         ret = regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 898                                 sizeof(regs));
 899         if (ret)
 900                 return ret;
 901
 902         return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 903                                   DS1388_BIT_WDE | DS1388_BIT_RST,
 904                                   DS1388_BIT_WDE | DS1388_BIT_RST);
 905 }
 906
 907 static int ds1388_wdt_stop(struct watchdog_device *wdt_dev)
 908 {
 909         struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 910
 911         return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 912                                   DS1388_BIT_WDE | DS1388_BIT_RST, 0);
 913 }
 914
 915 static int ds1388_wdt_ping(struct watchdog_device *wdt_dev)
 916 {
 917         struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 918         u8 regs[2];
 919
 920         return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 921                                 sizeof(regs));
 922 }
 923
 924 static int ds1388_wdt_set_timeout(struct watchdog_device *wdt_dev,
 925                                   unsigned int val)
 926 {
 927         struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 928         u8 regs[2];
 929
 930         wdt_dev->timeout = val;
 931         regs[0] = 0;
 932         regs[1] = bin2bcd(wdt_dev->timeout);
 933
 934         return regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 935                                  sizeof(regs));
 936 }
 937 #endif
 938
 939 static const struct rtc_class_ops rx8130_rtc_ops = {
 940         .read_time      = ds1307_get_time,
 941         .set_time       = ds1307_set_time,
 942         .read_alarm     = rx8130_read_alarm,
 943         .set_alarm      = rx8130_set_alarm,
 944         .alarm_irq_enable = rx8130_alarm_irq_enable,
 945 };
 946
 947 static const struct rtc_class_ops mcp794xx_rtc_ops = {
 948         .read_time      = ds1307_get_time,
 949         .set_time       = ds1307_set_time,
 950         .read_alarm     = mcp794xx_read_alarm,
 951         .set_alarm      = mcp794xx_set_alarm,
 952         .alarm_irq_enable = mcp794xx_alarm_irq_enable,
 953 };
 954
 955 static const struct rtc_class_ops m41txx_rtc_ops = {
 956         .read_time      = ds1307_get_time,
 957         .set_time       = ds1307_set_time,
 958         .read_alarm     = ds1337_read_alarm,
 959         .set_alarm      = ds1337_set_alarm,
 960         .alarm_irq_enable = ds1307_alarm_irq_enable,
 961         .read_offset    = m41txx_rtc_read_offset,
 962         .set_offset     = m41txx_rtc_set_offset,
 963 };
 964
 965 static const struct chip_desc chips[last_ds_type] = {
 966         [ds_1307] = {
 967                 .nvram_offset   = 8,
 968                 .nvram_size     = 56,
 969         },
 970         [ds_1308] = {
 971                 .nvram_offset   = 8,
 972                 .nvram_size     = 56,
 973         },
 974         [ds_1337] = {
 975                 .alarm          = 1,
 976                 .century_reg    = DS1307_REG_MONTH,
 977                 .century_bit    = DS1337_BIT_CENTURY,
 978         },
 979         [ds_1338] = {
 980                 .nvram_offset   = 8,
 981                 .nvram_size     = 56,
 982         },
 983         [ds_1339] = {
 984                 .alarm          = 1,
 985                 .century_reg    = DS1307_REG_MONTH,
 986                 .century_bit    = DS1337_BIT_CENTURY,
 987                 .bbsqi_bit      = DS1339_BIT_BBSQI,
 988                 .trickle_charger_reg = 0x10,
 989                 .do_trickle_setup = &do_trickle_setup_ds1339,
 990                 .requires_trickle_resistor = true,
 991                 .charge_default = true,
 992         },
 993         [ds_1340] = {
 994                 .century_reg    = DS1307_REG_HOUR,
 995                 .century_enable_bit = DS1340_BIT_CENTURY_EN,
 996                 .century_bit    = DS1340_BIT_CENTURY,
 997                 .do_trickle_setup = &do_trickle_setup_ds1339,
 998                 .trickle_charger_reg = 0x08,
 999                 .requires_trickle_resistor = true,
1000                 .charge_default = true,
1001         },
1002         [ds_1341] = {
1003                 .century_reg    = DS1307_REG_MONTH,
1004                 .century_bit    = DS1337_BIT_CENTURY,
1005         },
1006         [ds_1388] = {
1007                 .offset         = 1,
1008                 .trickle_charger_reg = 0x0a,
1009         },
1010         [ds_3231] = {
1011                 .alarm          = 1,
1012                 .century_reg    = DS1307_REG_MONTH,
1013                 .century_bit    = DS1337_BIT_CENTURY,
1014                 .bbsqi_bit      = DS3231_BIT_BBSQW,
1015         },
1016         [rx_8130] = {
1017                 .alarm          = 1,
1018                 /* this is battery backed SRAM */
1019                 .nvram_offset   = 0x20,
1020                 .nvram_size     = 4,    /* 32bit (4 word x 8 bit) */
1021                 .offset         = 0x10,
1022                 .irq_handler = rx8130_irq,
1023                 .rtc_ops = &rx8130_rtc_ops,
1024                 .trickle_charger_reg = RX8130_REG_CONTROL1,
1025                 .do_trickle_setup = &do_trickle_setup_rx8130,
1026         },
1027         [m41t0] = {
1028                 .rtc_ops        = &m41txx_rtc_ops,
1029         },
1030         [m41t00] = {
1031                 .rtc_ops        = &m41txx_rtc_ops,
1032         },
1033         [m41t11] = {
1034                 /* this is battery backed SRAM */
1035                 .nvram_offset   = 8,
1036                 .nvram_size     = 56,
1037                 .rtc_ops        = &m41txx_rtc_ops,
1038         },
1039         [mcp794xx] = {
1040                 .alarm          = 1,
1041                 /* this is battery backed SRAM */
1042                 .nvram_offset   = 0x20,
1043                 .nvram_size     = 0x40,
1044                 .irq_handler = mcp794xx_irq,
1045                 .rtc_ops = &mcp794xx_rtc_ops,
1046         },
1047 };
1048
1049 static const struct i2c_device_id ds1307_id[] = {
1050         { "ds1307", ds_1307 },
1051         { "ds1308", ds_1308 },
1052         { "ds1337", ds_1337 },
1053         { "ds1338", ds_1338 },
1054         { "ds1339", ds_1339 },
1055         { "ds1388", ds_1388 },
1056         { "ds1340", ds_1340 },
1057         { "ds1341", ds_1341 },
1058         { "ds3231", ds_3231 },
1059         { "m41t0", m41t0 },
1060         { "m41t00", m41t00 },
1061         { "m41t11", m41t11 },
1062         { "mcp7940x", mcp794xx },
1063         { "mcp7941x", mcp794xx },
1064         { "pt7c4338", ds_1307 },
1065         { "rx8025", rx_8025 },
1066         { "isl12057", ds_1337 },
1067         { "rx8130", rx_8130 },
1068         { }
1069 };
1070 MODULE_DEVICE_TABLE(i2c, ds1307_id);
1071
1072 static const struct of_device_id ds1307_of_match[] = {
1073         {
1074                 .compatible = "dallas,ds1307",
1075                 .data = (void *)ds_1307
1076         },
1077         {
1078                 .compatible = "dallas,ds1308",
1079                 .data = (void *)ds_1308
1080         },
1081         {
1082                 .compatible = "dallas,ds1337",
1083                 .data = (void *)ds_1337
1084         },
1085         {
1086                 .compatible = "dallas,ds1338",
1087                 .data = (void *)ds_1338
1088         },
1089         {
1090                 .compatible = "dallas,ds1339",
1091                 .data = (void *)ds_1339
1092         },
1093         {
1094                 .compatible = "dallas,ds1388",
1095                 .data = (void *)ds_1388
1096         },
1097         {
1098                 .compatible = "dallas,ds1340",
1099                 .data = (void *)ds_1340
1100         },
1101         {
1102                 .compatible = "dallas,ds1341",
1103                 .data = (void *)ds_1341
1104         },
1105         {
1106                 .compatible = "maxim,ds3231",
1107                 .data = (void *)ds_3231
1108         },
1109         {
1110                 .compatible = "st,m41t0",
1111                 .data = (void *)m41t0
1112         },
1113         {
1114                 .compatible = "st,m41t00",
1115                 .data = (void *)m41t00
1116         },
1117         {
1118                 .compatible = "st,m41t11",
1119                 .data = (void *)m41t11
1120         },
1121         {
1122                 .compatible = "microchip,mcp7940x",
1123                 .data = (void *)mcp794xx
1124         },
1125         {
1126                 .compatible = "microchip,mcp7941x",
1127                 .data = (void *)mcp794xx
1128         },
1129         {
1130                 .compatible = "pericom,pt7c4338",
1131                 .data = (void *)ds_1307
1132         },
1133         {
1134                 .compatible = "epson,rx8025",
1135                 .data = (void *)rx_8025
1136         },
1137         {
1138                 .compatible = "isil,isl12057",
1139                 .data = (void *)ds_1337
1140         },
1141         {
1142                 .compatible = "epson,rx8130",
1143                 .data = (void *)rx_8130
1144         },
1145         { }
1146 };
1147 MODULE_DEVICE_TABLE(of, ds1307_of_match);
1148
1149 /*
1150  * The ds1337 and ds1339 both have two alarms, but we only use the first
1151  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
1152  * signal; ds1339 chips have only one alarm signal.
1153  */
1154 static irqreturn_t ds1307_irq(int irq, void *dev_id)
1155 {
1156         struct ds1307           *ds1307 = dev_id;
1157         struct mutex            *lock = &ds1307->rtc->ops_lock;
1158         int                     stat, ret;
1159
1160         mutex_lock(lock);
1161         ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &stat);
1162         if (ret)
1163                 goto out;
1164
1165         if (stat & DS1337_BIT_A1I) {
1166                 stat &= ~DS1337_BIT_A1I;
1167                 regmap_write(ds1307->regmap, DS1337_REG_STATUS, stat);
1168
1169                 ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1170                                          DS1337_BIT_A1IE, 0);
1171                 if (ret)
1172                         goto out;
1173
1174                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
1175         }
1176
1177 out:
1178         mutex_unlock(lock);
1179
1180         return IRQ_HANDLED;
1181 }
1182
1183 /*----------------------------------------------------------------------*/
1184
1185 static const struct rtc_class_ops ds13xx_rtc_ops = {
1186         .read_time      = ds1307_get_time,
1187         .set_time       = ds1307_set_time,
1188         .read_alarm     = ds1337_read_alarm,
1189         .set_alarm      = ds1337_set_alarm,
1190         .alarm_irq_enable = ds1307_alarm_irq_enable,
1191 };
1192
1193 static ssize_t frequency_test_store(struct device *dev,
1194                                     struct device_attribute *attr,
1195                                     const char *buf, size_t count)
1196 {
1197         struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1198         bool freq_test_en;
1199         int ret;
1200
1201         ret = kstrtobool(buf, &freq_test_en);
1202         if (ret) {
1203                 dev_err(dev, "Failed to store RTC Frequency Test attribute\n");
1204                 return ret;
1205         }
1206
1207         regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL, M41TXX_BIT_FT,
1208                            freq_test_en ? M41TXX_BIT_FT : 0);
1209
1210         return count;
1211 }
1212
1213 static ssize_t frequency_test_show(struct device *dev,
1214                                    struct device_attribute *attr,
1215                                    char *buf)
1216 {
1217         struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1218         unsigned int ctrl_reg;
1219
1220         regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
1221
1222         return sysfs_emit(buf, (ctrl_reg & M41TXX_BIT_FT) ? "on\n" : "off\n");
1223 }
1224
1225 static DEVICE_ATTR_RW(frequency_test);
1226
1227 static struct attribute *rtc_freq_test_attrs[] = {
1228         &dev_attr_frequency_test.attr,
1229         NULL,
1230 };
1231
1232 static const struct attribute_group rtc_freq_test_attr_group = {
1233         .attrs          = rtc_freq_test_attrs,
1234 };
1235
1236 static int ds1307_add_frequency_test(struct ds1307 *ds1307)
1237 {
1238         int err;
1239
1240         switch (ds1307->type) {
1241         case m41t0:
1242         case m41t00:
1243         case m41t11:
1244                 err = rtc_add_group(ds1307->rtc, &rtc_freq_test_attr_group);
1245                 if (err)
1246                         return err;
1247                 break;
1248         default:
1249                 break;
1250         }
1251
1252         return 0;
1253 }
1254
1255 /*----------------------------------------------------------------------*/
1256
1257 static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
1258                              size_t bytes)
1259 {
1260         struct ds1307 *ds1307 = priv;
1261         const struct chip_desc *chip = &chips[ds1307->type];
1262
1263         return regmap_bulk_read(ds1307->regmap, chip->nvram_offset + offset,
1264                                 val, bytes);
1265 }
1266
1267 static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
1268                               size_t bytes)
1269 {
1270         struct ds1307 *ds1307 = priv;
1271         const struct chip_desc *chip = &chips[ds1307->type];
1272
1273         return regmap_bulk_write(ds1307->regmap, chip->nvram_offset + offset,
1274                                  val, bytes);
1275 }
1276
1277 /*----------------------------------------------------------------------*/
1278
1279 static u8 ds1307_trickle_init(struct ds1307 *ds1307,
1280                               const struct chip_desc *chip)
1281 {
1282         u32 ohms, chargeable;
1283         bool diode = chip->charge_default;
1284
1285         if (!chip->do_trickle_setup)
1286                 return 0;
1287
1288         if (device_property_read_u32(ds1307->dev, "trickle-resistor-ohms",
1289                                      &ohms) && chip->requires_trickle_resistor)
1290                 return 0;
1291
1292         /* aux-voltage-chargeable takes precedence over the deprecated
1293          * trickle-diode-disable
1294          */
1295         if (!device_property_read_u32(ds1307->dev, "aux-voltage-chargeable",
1296                                      &chargeable)) {
1297                 switch (chargeable) {
1298                 case 0:
1299                         diode = false;
1300                         break;
1301                 case 1:
1302                         diode = true;
1303                         break;
1304                 default:
1305                         dev_warn(ds1307->dev,
1306                                  "unsupported aux-voltage-chargeable value\n");
1307                         break;
1308                 }
1309         } else if (device_property_read_bool(ds1307->dev,
1310                                              "trickle-diode-disable")) {
1311                 diode = false;
1312         }
1313
1314         return chip->do_trickle_setup(ds1307, ohms, diode);
1315 }
1316
1317 /*----------------------------------------------------------------------*/
1318
1319 #if IS_REACHABLE(CONFIG_HWMON)
1320
1321 /*
1322  * Temperature sensor support for ds3231 devices.
1323  */
1324
1325 #define DS3231_REG_TEMPERATURE  0x11
1326
1327 /*
1328  * A user-initiated temperature conversion is not started by this function,
1329  * so the temperature is updated once every 64 seconds.
1330  */
1331 static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
1332 {
1333         struct ds1307 *ds1307 = dev_get_drvdata(dev);
1334         u8 temp_buf[2];
1335         s16 temp;
1336         int ret;
1337
1338         ret = regmap_bulk_read(ds1307->regmap, DS3231_REG_TEMPERATURE,
1339                                temp_buf, sizeof(temp_buf));
1340         if (ret)
1341                 return ret;
1342         /*
1343          * Temperature is represented as a 10-bit code with a resolution of
1344          * 0.25 degree celsius and encoded in two's complement format.
1345          */
1346         temp = (temp_buf[0] << 8) | temp_buf[1];
1347         temp >>= 6;
1348         *mC = temp * 250;
1349
1350         return 0;
1351 }
1352
1353 static ssize_t ds3231_hwmon_show_temp(struct device *dev,
1354                                       struct device_attribute *attr, char *buf)
1355 {
1356         int ret;
1357         s32 temp;
1358
1359         ret = ds3231_hwmon_read_temp(dev, &temp);
1360         if (ret)
1361                 return ret;
1362
1363         return sprintf(buf, "%d\n", temp);
1364 }
1365 static SENSOR_DEVICE_ATTR(temp1_input, 0444, ds3231_hwmon_show_temp,
1366                           NULL, 0);
1367
1368 static struct attribute *ds3231_hwmon_attrs[] = {
1369         &sensor_dev_attr_temp1_input.dev_attr.attr,
1370         NULL,
1371 };
1372 ATTRIBUTE_GROUPS(ds3231_hwmon);
1373
1374 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1375 {
1376         struct device *dev;
1377
1378         if (ds1307->type != ds_3231)
1379                 return;
1380
1381         dev = devm_hwmon_device_register_with_groups(ds1307->dev, ds1307->name,
1382                                                      ds1307,
1383                                                      ds3231_hwmon_groups);
1384         if (IS_ERR(dev)) {
1385                 dev_warn(ds1307->dev, "unable to register hwmon device %ld\n",
1386                          PTR_ERR(dev));
1387         }
1388 }
1389
1390 #else
1391
1392 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1393 {
1394 }
1395
1396 #endif /* CONFIG_RTC_DRV_DS1307_HWMON */
1397
1398 /*----------------------------------------------------------------------*/
1399
1400 /*
1401  * Square-wave output support for DS3231
1402  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1403  */
1404 #ifdef CONFIG_COMMON_CLK
1405
1406 enum {
1407         DS3231_CLK_SQW = 0,
1408         DS3231_CLK_32KHZ,
1409 };
1410
1411 #define clk_sqw_to_ds1307(clk)  \
1412         container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1413 #define clk_32khz_to_ds1307(clk)        \
1414         container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1415
1416 static int ds3231_clk_sqw_rates[] = {
1417         1,
1418         1024,
1419         4096,
1420         8192,
1421 };
1422
1423 static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1424 {
1425         struct mutex *lock = &ds1307->rtc->ops_lock;
1426         int ret;
1427
1428         mutex_lock(lock);
1429         ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1430                                  mask, value);
1431         mutex_unlock(lock);
1432
1433         return ret;
1434 }
1435
1436 static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1437                                                 unsigned long parent_rate)
1438 {
1439         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1440         int control, ret;
1441         int rate_sel = 0;
1442
1443         ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1444         if (ret)
1445                 return ret;
1446         if (control & DS1337_BIT_RS1)
1447                 rate_sel += 1;
1448         if (control & DS1337_BIT_RS2)
1449                 rate_sel += 2;
1450
1451         return ds3231_clk_sqw_rates[rate_sel];
1452 }
1453
1454 static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1455                                       unsigned long *prate)
1456 {
1457         int i;
1458
1459         for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1460                 if (ds3231_clk_sqw_rates[i] <= rate)
1461                         return ds3231_clk_sqw_rates[i];
1462         }
1463
1464         return 0;
1465 }
1466
1467 static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1468                                    unsigned long parent_rate)
1469 {
1470         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1471         int control = 0;
1472         int rate_sel;
1473
1474         for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1475                         rate_sel++) {
1476                 if (ds3231_clk_sqw_rates[rate_sel] == rate)
1477                         break;
1478         }
1479
1480         if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1481                 return -EINVAL;
1482
1483         if (rate_sel & 1)
1484                 control |= DS1337_BIT_RS1;
1485         if (rate_sel & 2)
1486                 control |= DS1337_BIT_RS2;
1487
1488         return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1489                                 control);
1490 }
1491
1492 static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1493 {
1494         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1495
1496         return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1497 }
1498
1499 static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1500 {
1501         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1502
1503         ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1504 }
1505
1506 static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1507 {
1508         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1509         int control, ret;
1510
1511         ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1512         if (ret)
1513                 return ret;
1514
1515         return !(control & DS1337_BIT_INTCN);
1516 }
1517
1518 static const struct clk_ops ds3231_clk_sqw_ops = {
1519         .prepare = ds3231_clk_sqw_prepare,
1520         .unprepare = ds3231_clk_sqw_unprepare,
1521         .is_prepared = ds3231_clk_sqw_is_prepared,
1522         .recalc_rate = ds3231_clk_sqw_recalc_rate,
1523         .round_rate = ds3231_clk_sqw_round_rate,
1524         .set_rate = ds3231_clk_sqw_set_rate,
1525 };
1526
1527 static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1528                                                   unsigned long parent_rate)
1529 {
1530         return 32768;
1531 }
1532
1533 static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1534 {
1535         struct mutex *lock = &ds1307->rtc->ops_lock;
1536         int ret;
1537
1538         mutex_lock(lock);
1539         ret = regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
1540                                  DS3231_BIT_EN32KHZ,
1541                                  enable ? DS3231_BIT_EN32KHZ : 0);
1542         mutex_unlock(lock);
1543
1544         return ret;
1545 }
1546
1547 static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1548 {
1549         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1550
1551         return ds3231_clk_32khz_control(ds1307, true);
1552 }
1553
1554 static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1555 {
1556         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1557
1558         ds3231_clk_32khz_control(ds1307, false);
1559 }
1560
1561 static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1562 {
1563         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1564         int status, ret;
1565
1566         ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &status);
1567         if (ret)
1568                 return ret;
1569
1570         return !!(status & DS3231_BIT_EN32KHZ);
1571 }
1572
1573 static const struct clk_ops ds3231_clk_32khz_ops = {
1574         .prepare = ds3231_clk_32khz_prepare,
1575         .unprepare = ds3231_clk_32khz_unprepare,
1576         .is_prepared = ds3231_clk_32khz_is_prepared,
1577         .recalc_rate = ds3231_clk_32khz_recalc_rate,
1578 };
1579
1580 static const char *ds3231_clks_names[] = {
1581         [DS3231_CLK_SQW] = "ds3231_clk_sqw",
1582         [DS3231_CLK_32KHZ] = "ds3231_clk_32khz",
1583 };
1584
1585 static struct clk_init_data ds3231_clks_init[] = {
1586         [DS3231_CLK_SQW] = {
1587                 .ops = &ds3231_clk_sqw_ops,
1588         },
1589         [DS3231_CLK_32KHZ] = {
1590                 .ops = &ds3231_clk_32khz_ops,
1591         },
1592 };
1593
1594 static int ds3231_clks_register(struct ds1307 *ds1307)
1595 {
1596         struct device_node *node = ds1307->dev->of_node;
1597         struct clk_onecell_data *onecell;
1598         int i;
1599
1600         onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
1601         if (!onecell)
1602                 return -ENOMEM;
1603
1604         onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1605         onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
1606                                      sizeof(onecell->clks[0]), GFP_KERNEL);
1607         if (!onecell->clks)
1608                 return -ENOMEM;
1609
1610         /* optional override of the clockname */
1611         device_property_read_string_array(ds1307->dev, "clock-output-names",
1612                                           ds3231_clks_names,
1613                                           ARRAY_SIZE(ds3231_clks_names));
1614
1615         for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1616                 struct clk_init_data init = ds3231_clks_init[i];
1617
1618                 /*
1619                  * Interrupt signal due to alarm conditions and square-wave
1620                  * output share same pin, so don't initialize both.
1621                  */
1622                 if (i == DS3231_CLK_SQW && test_bit(RTC_FEATURE_ALARM, ds1307->rtc->features))
1623                         continue;
1624
1625                 init.name = ds3231_clks_names[i];
1626                 ds1307->clks[i].init = &init;
1627
1628                 onecell->clks[i] = devm_clk_register(ds1307->dev,
1629                                                      &ds1307->clks[i]);
1630                 if (IS_ERR(onecell->clks[i]))
1631                         return PTR_ERR(onecell->clks[i]);
1632         }
1633
1634         if (node)
1635                 of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1636
1637         return 0;
1638 }
1639
1640 static void ds1307_clks_register(struct ds1307 *ds1307)
1641 {
1642         int ret;
1643
1644         if (ds1307->type != ds_3231)
1645                 return;
1646
1647         ret = ds3231_clks_register(ds1307);
1648         if (ret) {
1649                 dev_warn(ds1307->dev, "unable to register clock device %d\n",
1650                          ret);
1651         }
1652 }
1653
1654 #else
1655
1656 static void ds1307_clks_register(struct ds1307 *ds1307)
1657 {
1658 }
1659
1660 #endif /* CONFIG_COMMON_CLK */
1661
1662 #ifdef CONFIG_WATCHDOG_CORE
1663 static const struct watchdog_info ds1388_wdt_info = {
1664         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
1665         .identity = "DS1388 watchdog",
1666 };
1667
1668 static const struct watchdog_ops ds1388_wdt_ops = {
1669         .owner = THIS_MODULE,
1670         .start = ds1388_wdt_start,
1671         .stop = ds1388_wdt_stop,
1672         .ping = ds1388_wdt_ping,
1673         .set_timeout = ds1388_wdt_set_timeout,
1674
1675 };
1676
1677 static void ds1307_wdt_register(struct ds1307 *ds1307)
1678 {
1679         struct watchdog_device  *wdt;
1680         int err;
1681         int val;
1682
1683         if (ds1307->type != ds_1388)
1684                 return;
1685
1686         wdt = devm_kzalloc(ds1307->dev, sizeof(*wdt), GFP_KERNEL);
1687         if (!wdt)
1688                 return;
1689
1690         err = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
1691         if (!err && val & DS1388_BIT_WF)
1692                 wdt->bootstatus = WDIOF_CARDRESET;
1693
1694         wdt->info = &ds1388_wdt_info;
1695         wdt->ops = &ds1388_wdt_ops;
1696         wdt->timeout = 99;
1697         wdt->max_timeout = 99;
1698         wdt->min_timeout = 1;
1699
1700         watchdog_init_timeout(wdt, 0, ds1307->dev);
1701         watchdog_set_drvdata(wdt, ds1307);
1702         devm_watchdog_register_device(ds1307->dev, wdt);
1703 }
1704 #else
1705 static void ds1307_wdt_register(struct ds1307 *ds1307)
1706 {
1707 }
1708 #endif /* CONFIG_WATCHDOG_CORE */
1709
1710 static const struct regmap_config regmap_config = {
1711         .reg_bits = 8,
1712         .val_bits = 8,
1713 };
1714
1715 static int ds1307_probe(struct i2c_client *client)
1716 {
1717         const struct i2c_device_id *id = i2c_client_get_device_id(client);
1718         struct ds1307           *ds1307;
1719         const void              *match;
1720         int                     err = -ENODEV;
1721         int                     tmp;
1722         const struct chip_desc  *chip;
1723         bool                    want_irq;
1724         bool                    ds1307_can_wakeup_device = false;
1725         unsigned char           regs[8];
1726         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1727         u8                      trickle_charger_setup = 0;
1728
1729         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1730         if (!ds1307)
1731                 return -ENOMEM;
1732
1733         dev_set_drvdata(&client->dev, ds1307);
1734         ds1307->dev = &client->dev;
1735         ds1307->name = client->name;
1736
1737         ds1307->regmap = devm_regmap_init_i2c(client, &regmap_config);
1738         if (IS_ERR(ds1307->regmap)) {
1739                 dev_err(ds1307->dev, "regmap allocation failed\n");
1740                 return PTR_ERR(ds1307->regmap);
1741         }
1742
1743         i2c_set_clientdata(client, ds1307);
1744
1745         match = device_get_match_data(&client->dev);
1746         if (match) {
1747                 ds1307->type = (uintptr_t)match;
1748                 chip = &chips[ds1307->type];
1749         } else if (id) {
1750                 chip = &chips[id->driver_data];
1751                 ds1307->type = id->driver_data;
1752         } else {
1753                 return -ENODEV;
1754         }
1755
1756         want_irq = client->irq > 0 && chip->alarm;
1757
1758         if (!pdata)
1759                 trickle_charger_setup = ds1307_trickle_init(ds1307, chip);
1760         else if (pdata->trickle_charger_setup)
1761                 trickle_charger_setup = pdata->trickle_charger_setup;
1762
1763         if (trickle_charger_setup && chip->trickle_charger_reg) {
1764                 dev_dbg(ds1307->dev,
1765                         "writing trickle charger info 0x%x to 0x%x\n",
1766                         trickle_charger_setup, chip->trickle_charger_reg);
1767                 regmap_write(ds1307->regmap, chip->trickle_charger_reg,
1768                              trickle_charger_setup);
1769         }
1770
1771 /*
1772  * For devices with no IRQ directly connected to the SoC, the RTC chip
1773  * can be forced as a wakeup source by stating that explicitly in
1774  * the device's .dts file using the "wakeup-source" boolean property.
1775  * If the "wakeup-source" property is set, don't request an IRQ.
1776  * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1777  * if supported by the RTC.
1778  */
1779         if (chip->alarm && device_property_read_bool(&client->dev, "wakeup-source"))
1780                 ds1307_can_wakeup_device = true;
1781
1782         switch (ds1307->type) {
1783         case ds_1337:
1784         case ds_1339:
1785         case ds_1341:
1786         case ds_3231:
1787                 /* get registers that the "rtc" read below won't read... */
1788                 err = regmap_bulk_read(ds1307->regmap, DS1337_REG_CONTROL,
1789                                        regs, 2);
1790                 if (err) {
1791                         dev_dbg(ds1307->dev, "read error %d\n", err);
1792                         goto exit;
1793                 }
1794
1795                 /* oscillator off?  turn it on, so clock can tick. */
1796                 if (regs[0] & DS1337_BIT_nEOSC)
1797                         regs[0] &= ~DS1337_BIT_nEOSC;
1798
1799                 /*
1800                  * Using IRQ or defined as wakeup-source?
1801                  * Disable the square wave and both alarms.
1802                  * For some variants, be sure alarms can trigger when we're
1803                  * running on Vbackup (BBSQI/BBSQW)
1804                  */
1805                 if (want_irq || ds1307_can_wakeup_device) {
1806                         regs[0] |= DS1337_BIT_INTCN | chip->bbsqi_bit;
1807                         regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1808                 }
1809
1810                 regmap_write(ds1307->regmap, DS1337_REG_CONTROL,
1811                              regs[0]);
1812
1813                 /* oscillator fault?  clear flag, and warn */
1814                 if (regs[1] & DS1337_BIT_OSF) {
1815                         regmap_write(ds1307->regmap, DS1337_REG_STATUS,
1816                                      regs[1] & ~DS1337_BIT_OSF);
1817                         dev_warn(ds1307->dev, "SET TIME!\n");
1818                 }
1819                 break;
1820
1821         case rx_8025:
1822                 err = regmap_bulk_read(ds1307->regmap,
1823                                        RX8025_REG_CTRL1 << 4 | 0x08, regs, 2);
1824                 if (err) {
1825                         dev_dbg(ds1307->dev, "read error %d\n", err);
1826                         goto exit;
1827                 }
1828
1829                 /* oscillator off?  turn it on, so clock can tick. */
1830                 if (!(regs[1] & RX8025_BIT_XST)) {
1831                         regs[1] |= RX8025_BIT_XST;
1832                         regmap_write(ds1307->regmap,
1833                                      RX8025_REG_CTRL2 << 4 | 0x08,
1834                                      regs[1]);
1835                         dev_warn(ds1307->dev,
1836                                  "oscillator stop detected - SET TIME!\n");
1837                 }
1838
1839                 if (regs[1] & RX8025_BIT_PON) {
1840                         regs[1] &= ~RX8025_BIT_PON;
1841                         regmap_write(ds1307->regmap,
1842                                      RX8025_REG_CTRL2 << 4 | 0x08,
1843                                      regs[1]);
1844                         dev_warn(ds1307->dev, "power-on detected\n");
1845                 }
1846
1847                 if (regs[1] & RX8025_BIT_VDET) {
1848                         regs[1] &= ~RX8025_BIT_VDET;
1849                         regmap_write(ds1307->regmap,
1850                                      RX8025_REG_CTRL2 << 4 | 0x08,
1851                                      regs[1]);
1852                         dev_warn(ds1307->dev, "voltage drop detected\n");
1853                 }
1854
1855                 /* make sure we are running in 24hour mode */
1856                 if (!(regs[0] & RX8025_BIT_2412)) {
1857                         u8 hour;
1858
1859                         /* switch to 24 hour mode */
1860                         regmap_write(ds1307->regmap,
1861                                      RX8025_REG_CTRL1 << 4 | 0x08,
1862                                      regs[0] | RX8025_BIT_2412);
1863
1864                         err = regmap_bulk_read(ds1307->regmap,
1865                                                RX8025_REG_CTRL1 << 4 | 0x08,
1866                                                regs, 2);
1867                         if (err) {
1868                                 dev_dbg(ds1307->dev, "read error %d\n", err);
1869                                 goto exit;
1870                         }
1871
1872                         /* correct hour */
1873                         hour = bcd2bin(regs[DS1307_REG_HOUR]);
1874                         if (hour == 12)
1875                                 hour = 0;
1876                         if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1877                                 hour += 12;
1878
1879                         regmap_write(ds1307->regmap,
1880                                      DS1307_REG_HOUR << 4 | 0x08, hour);
1881                 }
1882                 break;
1883         case ds_1388:
1884                 err = regmap_read(ds1307->regmap, DS1388_REG_CONTROL, &tmp);
1885                 if (err) {
1886                         dev_dbg(ds1307->dev, "read error %d\n", err);
1887                         goto exit;
1888                 }
1889
1890                 /* oscillator off?  turn it on, so clock can tick. */
1891                 if (tmp & DS1388_BIT_nEOSC) {
1892                         tmp &= ~DS1388_BIT_nEOSC;
1893                         regmap_write(ds1307->regmap, DS1388_REG_CONTROL, tmp);
1894                 }
1895                 break;
1896         default:
1897                 break;
1898         }
1899
1900         /* read RTC registers */
1901         err = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
1902                                sizeof(regs));
1903         if (err) {
1904                 dev_dbg(ds1307->dev, "read error %d\n", err);
1905                 goto exit;
1906         }
1907
1908         if (ds1307->type == mcp794xx &&
1909             !(regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1910                 regmap_write(ds1307->regmap, DS1307_REG_WDAY,
1911                              regs[DS1307_REG_WDAY] |
1912                              MCP794XX_BIT_VBATEN);
1913         }
1914
1915         tmp = regs[DS1307_REG_HOUR];
1916         switch (ds1307->type) {
1917         case ds_1340:
1918         case m41t0:
1919         case m41t00:
1920         case m41t11:
1921                 /*
1922                  * NOTE: ignores century bits; fix before deploying
1923                  * systems that will run through year 2100.
1924                  */
1925                 break;
1926         case rx_8025:
1927                 break;
1928         default:
1929                 if (!(tmp & DS1307_BIT_12HR))
1930                         break;
1931
1932                 /*
1933                  * Be sure we're in 24 hour mode.  Multi-master systems
1934                  * take note...
1935                  */
1936                 tmp = bcd2bin(tmp & 0x1f);
1937                 if (tmp == 12)
1938                         tmp = 0;
1939                 if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1940                         tmp += 12;
1941                 regmap_write(ds1307->regmap, chip->offset + DS1307_REG_HOUR,
1942                              bin2bcd(tmp));
1943         }
1944
1945         ds1307->rtc = devm_rtc_allocate_device(ds1307->dev);
1946         if (IS_ERR(ds1307->rtc))
1947                 return PTR_ERR(ds1307->rtc);
1948
1949         if (want_irq || ds1307_can_wakeup_device)
1950                 device_set_wakeup_capable(ds1307->dev, true);
1951         else
1952                 clear_bit(RTC_FEATURE_ALARM, ds1307->rtc->features);
1953
1954         if (ds1307_can_wakeup_device && !want_irq) {
1955                 dev_info(ds1307->dev,
1956                          "'wakeup-source' is set, request for an IRQ is disabled!\n");
1957                 /* We cannot support UIE mode if we do not have an IRQ line */
1958                 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, ds1307->rtc->features);
1959         }
1960
1961         if (want_irq) {
1962                 err = devm_request_threaded_irq(ds1307->dev, client->irq, NULL,
1963                                                 chip->irq_handler ?: ds1307_irq,
1964                                                 IRQF_SHARED | IRQF_ONESHOT,
1965                                                 ds1307->name, ds1307);
1966                 if (err) {
1967                         client->irq = 0;
1968                         device_set_wakeup_capable(ds1307->dev, false);
1969                         clear_bit(RTC_FEATURE_ALARM, ds1307->rtc->features);
1970                         dev_err(ds1307->dev, "unable to request IRQ!\n");
1971                 } else {
1972                         dev_dbg(ds1307->dev, "got IRQ %d\n", client->irq);
1973                 }
1974         }
1975
1976         ds1307->rtc->ops = chip->rtc_ops ?: &ds13xx_rtc_ops;
1977         err = ds1307_add_frequency_test(ds1307);
1978         if (err)
1979                 return err;
1980
1981         err = devm_rtc_register_device(ds1307->rtc);
1982         if (err)
1983                 return err;
1984
1985         if (chip->nvram_size) {
1986                 struct nvmem_config nvmem_cfg = {
1987                         .name = "ds1307_nvram",
1988                         .word_size = 1,
1989                         .stride = 1,
1990                         .size = chip->nvram_size,
1991                         .reg_read = ds1307_nvram_read,
1992                         .reg_write = ds1307_nvram_write,
1993                         .priv = ds1307,
1994                 };
1995
1996                 devm_rtc_nvmem_register(ds1307->rtc, &nvmem_cfg);
1997         }
1998
1999         ds1307_hwmon_register(ds1307);
2000         ds1307_clks_register(ds1307);
2001         ds1307_wdt_register(ds1307);
2002
2003         return 0;
2004
2005 exit:
2006         return err;
2007 }
2008
2009 static struct i2c_driver ds1307_driver = {
2010         .driver = {
2011                 .name   = "rtc-ds1307",
2012                 .of_match_table = ds1307_of_match,
2013         },
2014         .probe          = ds1307_probe,
2015         .id_table       = ds1307_id,
2016 };
2017
2018 module_i2c_driver(ds1307_driver);
2019
2020 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
2021 MODULE_LICENSE("GPL");