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/acpi.h>
  12 #include <linux/bcd.h>
  13 #include <linux/i2c.h>
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/of_device.h>
  17 #include <linux/rtc/ds1307.h>
  18 #include <linux/rtc.h>
  19 #include <linux/slab.h>
  20 #include <linux/string.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/hwmon-sysfs.h>
  23 #include <linux/clk-provider.h>
  24 #include <linux/regmap.h>
  25
  26 /*
  27  * We can't determine type by probing, but if we expect pre-Linux code
  28  * to have set the chip up as a clock (turning on the oscillator and
  29  * setting the date and time), Linux can ignore the non-clock features.
  30  * That's a natural job for a factory or repair bench.
  31  */
  32 enum ds_type {
  33         ds_1307,
  34         ds_1308,
  35         ds_1337,
  36         ds_1338,
  37         ds_1339,
  38         ds_1340,
  39         ds_1341,
  40         ds_1388,
  41         ds_3231,
  42         m41t0,
  43         m41t00,
  44         m41t11,
  45         mcp794xx,
  46         rx_8025,
  47         rx_8130,
  48         last_ds_type /* always last */
  49         /* rs5c372 too?  different address... */
  50 };
  51
  52 /* RTC registers don't differ much, except for the century flag */
  53 #define DS1307_REG_SECS         0x00    /* 00-59 */
  54 #       define DS1307_BIT_CH            0x80
  55 #       define DS1340_BIT_nEOSC         0x80
  56 #       define MCP794XX_BIT_ST          0x80
  57 #define DS1307_REG_MIN          0x01    /* 00-59 */
  58 #       define M41T0_BIT_OF             0x80
  59 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  60 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  61 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  62 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  63 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  64 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  65 #       define MCP794XX_BIT_VBATEN      0x08
  66 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  67 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  68 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  69 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  70
  71 /*
  72  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  73  * start at 7, and they differ a LOT. Only control and status matter for
  74  * basic RTC date and time functionality; be careful using them.
  75  */
  76 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  77 #       define DS1307_BIT_OUT           0x80
  78 #       define DS1338_BIT_OSF           0x20
  79 #       define DS1307_BIT_SQWE          0x10
  80 #       define DS1307_BIT_RS1           0x02
  81 #       define DS1307_BIT_RS0           0x01
  82 #define DS1337_REG_CONTROL      0x0e
  83 #       define DS1337_BIT_nEOSC         0x80
  84 #       define DS1339_BIT_BBSQI         0x20
  85 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  86 #       define DS1337_BIT_RS2           0x10
  87 #       define DS1337_BIT_RS1           0x08
  88 #       define DS1337_BIT_INTCN         0x04
  89 #       define DS1337_BIT_A2IE          0x02
  90 #       define DS1337_BIT_A1IE          0x01
  91 #define DS1340_REG_CONTROL      0x07
  92 #       define DS1340_BIT_OUT           0x80
  93 #       define DS1340_BIT_FT            0x40
  94 #       define DS1340_BIT_CALIB_SIGN    0x20
  95 #       define DS1340_M_CALIBRATION     0x1f
  96 #define DS1340_REG_FLAG         0x09
  97 #       define DS1340_BIT_OSF           0x80
  98 #define DS1337_REG_STATUS       0x0f
  99 #       define DS1337_BIT_OSF           0x80
 100 #       define DS3231_BIT_EN32KHZ       0x08
 101 #       define DS1337_BIT_A2I           0x02
 102 #       define DS1337_BIT_A1I           0x01
 103 #define DS1339_REG_ALARM1_SECS  0x07
 104
 105 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
 106
 107 #define RX8025_REG_CTRL1        0x0e
 108 #       define RX8025_BIT_2412          0x20
 109 #define RX8025_REG_CTRL2        0x0f
 110 #       define RX8025_BIT_PON           0x10
 111 #       define RX8025_BIT_VDET          0x40
 112 #       define RX8025_BIT_XST           0x20
 113
 114 #define RX8130_REG_ALARM_MIN            0x17
 115 #define RX8130_REG_ALARM_HOUR           0x18
 116 #define RX8130_REG_ALARM_WEEK_OR_DAY    0x19
 117 #define RX8130_REG_EXTENSION            0x1c
 118 #define RX8130_REG_EXTENSION_WADA       BIT(3)
 119 #define RX8130_REG_FLAG                 0x1d
 120 #define RX8130_REG_FLAG_VLF             BIT(1)
 121 #define RX8130_REG_FLAG_AF              BIT(3)
 122 #define RX8130_REG_CONTROL0             0x1e
 123 #define RX8130_REG_CONTROL0_AIE         BIT(3)
 124
 125 #define MCP794XX_REG_CONTROL            0x07
 126 #       define MCP794XX_BIT_ALM0_EN     0x10
 127 #       define MCP794XX_BIT_ALM1_EN     0x20
 128 #define MCP794XX_REG_ALARM0_BASE        0x0a
 129 #define MCP794XX_REG_ALARM0_CTRL        0x0d
 130 #define MCP794XX_REG_ALARM1_BASE        0x11
 131 #define MCP794XX_REG_ALARM1_CTRL        0x14
 132 #       define MCP794XX_BIT_ALMX_IF     BIT(3)
 133 #       define MCP794XX_BIT_ALMX_C0     BIT(4)
 134 #       define MCP794XX_BIT_ALMX_C1     BIT(5)
 135 #       define MCP794XX_BIT_ALMX_C2     BIT(6)
 136 #       define MCP794XX_BIT_ALMX_POL    BIT(7)
 137 #       define MCP794XX_MSK_ALMX_MATCH  (MCP794XX_BIT_ALMX_C0 | \
 138                                          MCP794XX_BIT_ALMX_C1 | \
 139                                          MCP794XX_BIT_ALMX_C2)
 140
 141 #define M41TXX_REG_CONTROL      0x07
 142 #       define M41TXX_BIT_OUT           BIT(7)
 143 #       define M41TXX_BIT_FT            BIT(6)
 144 #       define M41TXX_BIT_CALIB_SIGN    BIT(5)
 145 #       define M41TXX_M_CALIBRATION     GENMASK(4, 0)
 146
 147 /* negative offset step is -2.034ppm */
 148 #define M41TXX_NEG_OFFSET_STEP_PPB      2034
 149 /* positive offset step is +4.068ppm */
 150 #define M41TXX_POS_OFFSET_STEP_PPB      4068
 151 /* Min and max values supported with 'offset' interface by M41TXX */
 152 #define M41TXX_MIN_OFFSET       ((-31) * M41TXX_NEG_OFFSET_STEP_PPB)
 153 #define M41TXX_MAX_OFFSET       ((31) * M41TXX_POS_OFFSET_STEP_PPB)
 154
 155 struct ds1307 {
 156         enum ds_type            type;
 157         unsigned long           flags;
 158 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 159 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 160         struct device           *dev;
 161         struct regmap           *regmap;
 162         const char              *name;
 163         struct rtc_device       *rtc;
 164 #ifdef CONFIG_COMMON_CLK
 165         struct clk_hw           clks[2];
 166 #endif
 167 };
 168
 169 struct chip_desc {
 170         unsigned                alarm:1;
 171         u16                     nvram_offset;
 172         u16                     nvram_size;
 173         u8                      offset; /* register's offset */
 174         u8                      century_reg;
 175         u8                      century_enable_bit;
 176         u8                      century_bit;
 177         u8                      bbsqi_bit;
 178         irq_handler_t           irq_handler;
 179         const struct rtc_class_ops *rtc_ops;
 180         u16                     trickle_charger_reg;
 181         u8                      (*do_trickle_setup)(struct ds1307 *, u32,
 182                                                     bool);
 183 };
 184
 185 static const struct chip_desc chips[last_ds_type];
 186
 187 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 188 {
 189         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 190         int             tmp, ret;
 191         const struct chip_desc *chip = &chips[ds1307->type];
 192         u8 regs[7];
 193
 194         if (ds1307->type == rx_8130) {
 195                 unsigned int regflag;
 196                 ret = regmap_read(ds1307->regmap, RX8130_REG_FLAG, &regflag);
 197                 if (ret) {
 198                         dev_err(dev, "%s error %d\n", "read", ret);
 199                         return ret;
 200                 }
 201
 202                 if (regflag & RX8130_REG_FLAG_VLF) {
 203                         dev_warn_once(dev, "oscillator failed, set time!\n");
 204                         return -EINVAL;
 205                 }
 206         }
 207
 208         /* read the RTC date and time registers all at once */
 209         ret = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
 210                                sizeof(regs));
 211         if (ret) {
 212                 dev_err(dev, "%s error %d\n", "read", ret);
 213                 return ret;
 214         }
 215
 216         dev_dbg(dev, "%s: %7ph\n", "read", regs);
 217
 218         /* if oscillator fail bit is set, no data can be trusted */
 219         if (ds1307->type == m41t0 &&
 220             regs[DS1307_REG_MIN] & M41T0_BIT_OF) {
 221                 dev_warn_once(dev, "oscillator failed, set time!\n");
 222                 return -EINVAL;
 223         }
 224
 225         tmp = regs[DS1307_REG_SECS];
 226         switch (ds1307->type) {
 227         case ds_1307:
 228         case m41t0:
 229         case m41t00:
 230         case m41t11:
 231                 if (tmp & DS1307_BIT_CH)
 232                         return -EINVAL;
 233                 break;
 234         case ds_1308:
 235         case ds_1338:
 236                 if (tmp & DS1307_BIT_CH)
 237                         return -EINVAL;
 238
 239                 ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &tmp);
 240                 if (ret)
 241                         return ret;
 242                 if (tmp & DS1338_BIT_OSF)
 243                         return -EINVAL;
 244                 break;
 245         case ds_1340:
 246                 if (tmp & DS1340_BIT_nEOSC)
 247                         return -EINVAL;
 248
 249                 ret = regmap_read(ds1307->regmap, DS1340_REG_FLAG, &tmp);
 250                 if (ret)
 251                         return ret;
 252                 if (tmp & DS1340_BIT_OSF)
 253                         return -EINVAL;
 254                 break;
 255         case mcp794xx:
 256                 if (!(tmp & MCP794XX_BIT_ST))
 257                         return -EINVAL;
 258
 259                 break;
 260         default:
 261                 break;
 262         }
 263
 264         t->tm_sec = bcd2bin(regs[DS1307_REG_SECS] & 0x7f);
 265         t->tm_min = bcd2bin(regs[DS1307_REG_MIN] & 0x7f);
 266         tmp = regs[DS1307_REG_HOUR] & 0x3f;
 267         t->tm_hour = bcd2bin(tmp);
 268         t->tm_wday = bcd2bin(regs[DS1307_REG_WDAY] & 0x07) - 1;
 269         t->tm_mday = bcd2bin(regs[DS1307_REG_MDAY] & 0x3f);
 270         tmp = regs[DS1307_REG_MONTH] & 0x1f;
 271         t->tm_mon = bcd2bin(tmp) - 1;
 272         t->tm_year = bcd2bin(regs[DS1307_REG_YEAR]) + 100;
 273
 274         if (regs[chip->century_reg] & chip->century_bit &&
 275             IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
 276                 t->tm_year += 100;
 277
 278         dev_dbg(dev, "%s secs=%d, mins=%d, "
 279                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 280                 "read", t->tm_sec, t->tm_min,
 281                 t->tm_hour, t->tm_mday,
 282                 t->tm_mon, t->tm_year, t->tm_wday);
 283
 284         return 0;
 285 }
 286
 287 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 288 {
 289         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 290         const struct chip_desc *chip = &chips[ds1307->type];
 291         int             result;
 292         int             tmp;
 293         u8              regs[7];
 294
 295         dev_dbg(dev, "%s secs=%d, mins=%d, "
 296                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 297                 "write", t->tm_sec, t->tm_min,
 298                 t->tm_hour, t->tm_mday,
 299                 t->tm_mon, t->tm_year, t->tm_wday);
 300
 301         if (t->tm_year < 100)
 302                 return -EINVAL;
 303
 304 #ifdef CONFIG_RTC_DRV_DS1307_CENTURY
 305         if (t->tm_year > (chip->century_bit ? 299 : 199))
 306                 return -EINVAL;
 307 #else
 308         if (t->tm_year > 199)
 309                 return -EINVAL;
 310 #endif
 311
 312         regs[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 313         regs[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 314         regs[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 315         regs[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 316         regs[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 317         regs[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 318
 319         /* assume 20YY not 19YY */
 320         tmp = t->tm_year - 100;
 321         regs[DS1307_REG_YEAR] = bin2bcd(tmp);
 322
 323         if (chip->century_enable_bit)
 324                 regs[chip->century_reg] |= chip->century_enable_bit;
 325         if (t->tm_year > 199 && chip->century_bit)
 326                 regs[chip->century_reg] |= chip->century_bit;
 327
 328         switch (ds1307->type) {
 329         case ds_1308:
 330         case ds_1338:
 331                 regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
 332                                    DS1338_BIT_OSF, 0);
 333                 break;
 334         case ds_1340:
 335                 regmap_update_bits(ds1307->regmap, DS1340_REG_FLAG,
 336                                    DS1340_BIT_OSF, 0);
 337                 break;
 338         case mcp794xx:
 339                 /*
 340                  * these bits were cleared when preparing the date/time
 341                  * values and need to be set again before writing the
 342                  * regsfer out to the device.
 343                  */
 344                 regs[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
 345                 regs[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
 346                 break;
 347         default:
 348                 break;
 349         }
 350
 351         dev_dbg(dev, "%s: %7ph\n", "write", regs);
 352
 353         result = regmap_bulk_write(ds1307->regmap, chip->offset, regs,
 354                                    sizeof(regs));
 355         if (result) {
 356                 dev_err(dev, "%s error %d\n", "write", result);
 357                 return result;
 358         }
 359
 360         if (ds1307->type == rx_8130) {
 361                 /* clear Voltage Loss Flag as data is available now */
 362                 result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
 363                                       ~(u8)RX8130_REG_FLAG_VLF);
 364                 if (result) {
 365                         dev_err(dev, "%s error %d\n", "write", result);
 366                         return result;
 367                 }
 368         }
 369
 370         return 0;
 371 }
 372
 373 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 374 {
 375         struct ds1307           *ds1307 = dev_get_drvdata(dev);
 376         int                     ret;
 377         u8                      regs[9];
 378
 379         if (!test_bit(HAS_ALARM, &ds1307->flags))
 380                 return -EINVAL;
 381
 382         /* read all ALARM1, ALARM2, and status registers at once */
 383         ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS,
 384                                regs, sizeof(regs));
 385         if (ret) {
 386                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 387                 return ret;
 388         }
 389
 390         dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
 391                 &regs[0], &regs[4], &regs[7]);
 392
 393         /*
 394          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 395          * and that all four fields are checked matches
 396          */
 397         t->time.tm_sec = bcd2bin(regs[0] & 0x7f);
 398         t->time.tm_min = bcd2bin(regs[1] & 0x7f);
 399         t->time.tm_hour = bcd2bin(regs[2] & 0x3f);
 400         t->time.tm_mday = bcd2bin(regs[3] & 0x3f);
 401
 402         /* ... and status */
 403         t->enabled = !!(regs[7] & DS1337_BIT_A1IE);
 404         t->pending = !!(regs[8] & DS1337_BIT_A1I);
 405
 406         dev_dbg(dev, "%s secs=%d, mins=%d, "
 407                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 408                 "alarm read", t->time.tm_sec, t->time.tm_min,
 409                 t->time.tm_hour, t->time.tm_mday,
 410                 t->enabled, t->pending);
 411
 412         return 0;
 413 }
 414
 415 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 416 {
 417         struct ds1307           *ds1307 = dev_get_drvdata(dev);
 418         unsigned char           regs[9];
 419         u8                      control, status;
 420         int                     ret;
 421
 422         if (!test_bit(HAS_ALARM, &ds1307->flags))
 423                 return -EINVAL;
 424
 425         dev_dbg(dev, "%s secs=%d, mins=%d, "
 426                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 427                 "alarm set", t->time.tm_sec, t->time.tm_min,
 428                 t->time.tm_hour, t->time.tm_mday,
 429                 t->enabled, t->pending);
 430
 431         /* read current status of both alarms and the chip */
 432         ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
 433                                sizeof(regs));
 434         if (ret) {
 435                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 436                 return ret;
 437         }
 438         control = regs[7];
 439         status = regs[8];
 440
 441         dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
 442                 &regs[0], &regs[4], control, status);
 443
 444         /* set ALARM1, using 24 hour and day-of-month modes */
 445         regs[0] = bin2bcd(t->time.tm_sec);
 446         regs[1] = bin2bcd(t->time.tm_min);
 447         regs[2] = bin2bcd(t->time.tm_hour);
 448         regs[3] = bin2bcd(t->time.tm_mday);
 449
 450         /* set ALARM2 to non-garbage */
 451         regs[4] = 0;
 452         regs[5] = 0;
 453         regs[6] = 0;
 454
 455         /* disable alarms */
 456         regs[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 457         regs[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 458
 459         ret = regmap_bulk_write(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
 460                                 sizeof(regs));
 461         if (ret) {
 462                 dev_err(dev, "can't set alarm time\n");
 463                 return ret;
 464         }
 465
 466         /* optionally enable ALARM1 */
 467         if (t->enabled) {
 468                 dev_dbg(dev, "alarm IRQ armed\n");
 469                 regs[7] |= DS1337_BIT_A1IE;     /* only ALARM1 is used */
 470                 regmap_write(ds1307->regmap, DS1337_REG_CONTROL, regs[7]);
 471         }
 472
 473         return 0;
 474 }
 475
 476 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 477 {
 478         struct ds1307           *ds1307 = dev_get_drvdata(dev);
 479
 480         if (!test_bit(HAS_ALARM, &ds1307->flags))
 481                 return -ENOTTY;
 482
 483         return regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
 484                                   DS1337_BIT_A1IE,
 485                                   enabled ? DS1337_BIT_A1IE : 0);
 486 }
 487
 488 static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307, u32 ohms, bool diode)
 489 {
 490         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
 491                 DS1307_TRICKLE_CHARGER_NO_DIODE;
 492
 493         switch (ohms) {
 494         case 250:
 495                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
 496                 break;
 497         case 2000:
 498                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
 499                 break;
 500         case 4000:
 501                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
 502                 break;
 503         default:
 504                 dev_warn(ds1307->dev,
 505                          "Unsupported ohm value %u in dt\n", ohms);
 506                 return 0;
 507         }
 508         return setup;
 509 }
 510
 511 static irqreturn_t rx8130_irq(int irq, void *dev_id)
 512 {
 513         struct ds1307           *ds1307 = dev_id;
 514         struct mutex            *lock = &ds1307->rtc->ops_lock;
 515         u8 ctl[3];
 516         int ret;
 517
 518         mutex_lock(lock);
 519
 520         /* Read control registers. */
 521         ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 522                                sizeof(ctl));
 523         if (ret < 0)
 524                 goto out;
 525         if (!(ctl[1] & RX8130_REG_FLAG_AF))
 526                 goto out;
 527         ctl[1] &= ~RX8130_REG_FLAG_AF;
 528         ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 529
 530         ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 531                                 sizeof(ctl));
 532         if (ret < 0)
 533                 goto out;
 534
 535         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 536
 537 out:
 538         mutex_unlock(lock);
 539
 540         return IRQ_HANDLED;
 541 }
 542
 543 static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 544 {
 545         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 546         u8 ald[3], ctl[3];
 547         int ret;
 548
 549         if (!test_bit(HAS_ALARM, &ds1307->flags))
 550                 return -EINVAL;
 551
 552         /* Read alarm registers. */
 553         ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
 554                                sizeof(ald));
 555         if (ret < 0)
 556                 return ret;
 557
 558         /* Read control registers. */
 559         ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 560                                sizeof(ctl));
 561         if (ret < 0)
 562                 return ret;
 563
 564         t->enabled = !!(ctl[2] & RX8130_REG_CONTROL0_AIE);
 565         t->pending = !!(ctl[1] & RX8130_REG_FLAG_AF);
 566
 567         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 568         t->time.tm_sec = -1;
 569         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 570         t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
 571         t->time.tm_wday = -1;
 572         t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
 573         t->time.tm_mon = -1;
 574         t->time.tm_year = -1;
 575         t->time.tm_yday = -1;
 576         t->time.tm_isdst = -1;
 577
 578         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
 579                 __func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 580                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);
 581
 582         return 0;
 583 }
 584
 585 static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 586 {
 587         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 588         u8 ald[3], ctl[3];
 589         int ret;
 590
 591         if (!test_bit(HAS_ALARM, &ds1307->flags))
 592                 return -EINVAL;
 593
 594         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 595                 "enabled=%d pending=%d\n", __func__,
 596                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 597                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 598                 t->enabled, t->pending);
 599
 600         /* Read control registers. */
 601         ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 602                                sizeof(ctl));
 603         if (ret < 0)
 604                 return ret;
 605
 606         ctl[0] &= RX8130_REG_EXTENSION_WADA;
 607         ctl[1] &= ~RX8130_REG_FLAG_AF;
 608         ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 609
 610         ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 611                                 sizeof(ctl));
 612         if (ret < 0)
 613                 return ret;
 614
 615         /* Hardware alarm precision is 1 minute! */
 616         ald[0] = bin2bcd(t->time.tm_min);
 617         ald[1] = bin2bcd(t->time.tm_hour);
 618         ald[2] = bin2bcd(t->time.tm_mday);
 619
 620         ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
 621                                 sizeof(ald));
 622         if (ret < 0)
 623                 return ret;
 624
 625         if (!t->enabled)
 626                 return 0;
 627
 628         ctl[2] |= RX8130_REG_CONTROL0_AIE;
 629
 630         return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, ctl[2]);
 631 }
 632
 633 static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)
 634 {
 635         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 636         int ret, reg;
 637
 638         if (!test_bit(HAS_ALARM, &ds1307->flags))
 639                 return -EINVAL;
 640
 641         ret = regmap_read(ds1307->regmap, RX8130_REG_CONTROL0, &reg);
 642         if (ret < 0)
 643                 return ret;
 644
 645         if (enabled)
 646                 reg |= RX8130_REG_CONTROL0_AIE;
 647         else
 648                 reg &= ~RX8130_REG_CONTROL0_AIE;
 649
 650         return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, reg);
 651 }
 652
 653 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
 654 {
 655         struct ds1307           *ds1307 = dev_id;
 656         struct mutex            *lock = &ds1307->rtc->ops_lock;
 657         int reg, ret;
 658
 659         mutex_lock(lock);
 660
 661         /* Check and clear alarm 0 interrupt flag. */
 662         ret = regmap_read(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, &reg);
 663         if (ret)
 664                 goto out;
 665         if (!(reg & MCP794XX_BIT_ALMX_IF))
 666                 goto out;
 667         reg &= ~MCP794XX_BIT_ALMX_IF;
 668         ret = regmap_write(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, reg);
 669         if (ret)
 670                 goto out;
 671
 672         /* Disable alarm 0. */
 673         ret = regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
 674                                  MCP794XX_BIT_ALM0_EN, 0);
 675         if (ret)
 676                 goto out;
 677
 678         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 679
 680 out:
 681         mutex_unlock(lock);
 682
 683         return IRQ_HANDLED;
 684 }
 685
 686 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 687 {
 688         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 689         u8 regs[10];
 690         int ret;
 691
 692         if (!test_bit(HAS_ALARM, &ds1307->flags))
 693                 return -EINVAL;
 694
 695         /* Read control and alarm 0 registers. */
 696         ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 697                                sizeof(regs));
 698         if (ret)
 699                 return ret;
 700
 701         t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
 702
 703         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 704         t->time.tm_sec = bcd2bin(regs[3] & 0x7f);
 705         t->time.tm_min = bcd2bin(regs[4] & 0x7f);
 706         t->time.tm_hour = bcd2bin(regs[5] & 0x3f);
 707         t->time.tm_wday = bcd2bin(regs[6] & 0x7) - 1;
 708         t->time.tm_mday = bcd2bin(regs[7] & 0x3f);
 709         t->time.tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
 710         t->time.tm_year = -1;
 711         t->time.tm_yday = -1;
 712         t->time.tm_isdst = -1;
 713
 714         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 715                 "enabled=%d polarity=%d irq=%d match=%lu\n", __func__,
 716                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 717                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 718                 !!(regs[6] & MCP794XX_BIT_ALMX_POL),
 719                 !!(regs[6] & MCP794XX_BIT_ALMX_IF),
 720                 (regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
 721
 722         return 0;
 723 }
 724
 725 /*
 726  * We may have a random RTC weekday, therefore calculate alarm weekday based
 727  * on current weekday we read from the RTC timekeeping regs
 728  */
 729 static int mcp794xx_alm_weekday(struct device *dev, struct rtc_time *tm_alarm)
 730 {
 731         struct rtc_time tm_now;
 732         int days_now, days_alarm, ret;
 733
 734         ret = ds1307_get_time(dev, &tm_now);
 735         if (ret)
 736                 return ret;
 737
 738         days_now = div_s64(rtc_tm_to_time64(&tm_now), 24 * 60 * 60);
 739         days_alarm = div_s64(rtc_tm_to_time64(tm_alarm), 24 * 60 * 60);
 740
 741         return (tm_now.tm_wday + days_alarm - days_now) % 7 + 1;
 742 }
 743
 744 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 745 {
 746         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 747         unsigned char regs[10];
 748         int wday, ret;
 749
 750         if (!test_bit(HAS_ALARM, &ds1307->flags))
 751                 return -EINVAL;
 752
 753         wday = mcp794xx_alm_weekday(dev, &t->time);
 754         if (wday < 0)
 755                 return wday;
 756
 757         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 758                 "enabled=%d pending=%d\n", __func__,
 759                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 760                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 761                 t->enabled, t->pending);
 762
 763         /* Read control and alarm 0 registers. */
 764         ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 765                                sizeof(regs));
 766         if (ret)
 767                 return ret;
 768
 769         /* Set alarm 0, using 24-hour and day-of-month modes. */
 770         regs[3] = bin2bcd(t->time.tm_sec);
 771         regs[4] = bin2bcd(t->time.tm_min);
 772         regs[5] = bin2bcd(t->time.tm_hour);
 773         regs[6] = wday;
 774         regs[7] = bin2bcd(t->time.tm_mday);
 775         regs[8] = bin2bcd(t->time.tm_mon + 1);
 776
 777         /* Clear the alarm 0 interrupt flag. */
 778         regs[6] &= ~MCP794XX_BIT_ALMX_IF;
 779         /* Set alarm match: second, minute, hour, day, date, month. */
 780         regs[6] |= MCP794XX_MSK_ALMX_MATCH;
 781         /* Disable interrupt. We will not enable until completely programmed */
 782         regs[0] &= ~MCP794XX_BIT_ALM0_EN;
 783
 784         ret = regmap_bulk_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 785                                 sizeof(regs));
 786         if (ret)
 787                 return ret;
 788
 789         if (!t->enabled)
 790                 return 0;
 791         regs[0] |= MCP794XX_BIT_ALM0_EN;
 792         return regmap_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs[0]);
 793 }
 794
 795 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 796 {
 797         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 798
 799         if (!test_bit(HAS_ALARM, &ds1307->flags))
 800                 return -EINVAL;
 801
 802         return regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
 803                                   MCP794XX_BIT_ALM0_EN,
 804                                   enabled ? MCP794XX_BIT_ALM0_EN : 0);
 805 }
 806
 807 static int m41txx_rtc_read_offset(struct device *dev, long *offset)
 808 {
 809         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 810         unsigned int ctrl_reg;
 811         u8 val;
 812
 813         regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
 814
 815         val = ctrl_reg & M41TXX_M_CALIBRATION;
 816
 817         /* check if positive */
 818         if (ctrl_reg & M41TXX_BIT_CALIB_SIGN)
 819                 *offset = (val * M41TXX_POS_OFFSET_STEP_PPB);
 820         else
 821                 *offset = -(val * M41TXX_NEG_OFFSET_STEP_PPB);
 822
 823         return 0;
 824 }
 825
 826 static int m41txx_rtc_set_offset(struct device *dev, long offset)
 827 {
 828         struct ds1307 *ds1307 = dev_get_drvdata(dev);
 829         unsigned int ctrl_reg;
 830
 831         if ((offset < M41TXX_MIN_OFFSET) || (offset > M41TXX_MAX_OFFSET))
 832                 return -ERANGE;
 833
 834         if (offset >= 0) {
 835                 ctrl_reg = DIV_ROUND_CLOSEST(offset,
 836                                              M41TXX_POS_OFFSET_STEP_PPB);
 837                 ctrl_reg |= M41TXX_BIT_CALIB_SIGN;
 838         } else {
 839                 ctrl_reg = DIV_ROUND_CLOSEST(abs(offset),
 840                                              M41TXX_NEG_OFFSET_STEP_PPB);
 841         }
 842
 843         return regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL,
 844                                   M41TXX_M_CALIBRATION | M41TXX_BIT_CALIB_SIGN,
 845                                   ctrl_reg);
 846 }
 847
 848 static const struct rtc_class_ops rx8130_rtc_ops = {
 849         .read_time      = ds1307_get_time,
 850         .set_time       = ds1307_set_time,
 851         .read_alarm     = rx8130_read_alarm,
 852         .set_alarm      = rx8130_set_alarm,
 853         .alarm_irq_enable = rx8130_alarm_irq_enable,
 854 };
 855
 856 static const struct rtc_class_ops mcp794xx_rtc_ops = {
 857         .read_time      = ds1307_get_time,
 858         .set_time       = ds1307_set_time,
 859         .read_alarm     = mcp794xx_read_alarm,
 860         .set_alarm      = mcp794xx_set_alarm,
 861         .alarm_irq_enable = mcp794xx_alarm_irq_enable,
 862 };
 863
 864 static const struct rtc_class_ops m41txx_rtc_ops = {
 865         .read_time      = ds1307_get_time,
 866         .set_time       = ds1307_set_time,
 867         .read_alarm     = ds1337_read_alarm,
 868         .set_alarm      = ds1337_set_alarm,
 869         .alarm_irq_enable = ds1307_alarm_irq_enable,
 870         .read_offset    = m41txx_rtc_read_offset,
 871         .set_offset     = m41txx_rtc_set_offset,
 872 };
 873
 874 static const struct chip_desc chips[last_ds_type] = {
 875         [ds_1307] = {
 876                 .nvram_offset   = 8,
 877                 .nvram_size     = 56,
 878         },
 879         [ds_1308] = {
 880                 .nvram_offset   = 8,
 881                 .nvram_size     = 56,
 882         },
 883         [ds_1337] = {
 884                 .alarm          = 1,
 885                 .century_reg    = DS1307_REG_MONTH,
 886                 .century_bit    = DS1337_BIT_CENTURY,
 887         },
 888         [ds_1338] = {
 889                 .nvram_offset   = 8,
 890                 .nvram_size     = 56,
 891         },
 892         [ds_1339] = {
 893                 .alarm          = 1,
 894                 .century_reg    = DS1307_REG_MONTH,
 895                 .century_bit    = DS1337_BIT_CENTURY,
 896                 .bbsqi_bit      = DS1339_BIT_BBSQI,
 897                 .trickle_charger_reg = 0x10,
 898                 .do_trickle_setup = &do_trickle_setup_ds1339,
 899         },
 900         [ds_1340] = {
 901                 .century_reg    = DS1307_REG_HOUR,
 902                 .century_enable_bit = DS1340_BIT_CENTURY_EN,
 903                 .century_bit    = DS1340_BIT_CENTURY,
 904                 .do_trickle_setup = &do_trickle_setup_ds1339,
 905                 .trickle_charger_reg = 0x08,
 906         },
 907         [ds_1341] = {
 908                 .century_reg    = DS1307_REG_MONTH,
 909                 .century_bit    = DS1337_BIT_CENTURY,
 910         },
 911         [ds_1388] = {
 912                 .offset         = 1,
 913                 .trickle_charger_reg = 0x0a,
 914         },
 915         [ds_3231] = {
 916                 .alarm          = 1,
 917                 .century_reg    = DS1307_REG_MONTH,
 918                 .century_bit    = DS1337_BIT_CENTURY,
 919                 .bbsqi_bit      = DS3231_BIT_BBSQW,
 920         },
 921         [rx_8130] = {
 922                 .alarm          = 1,
 923                 /* this is battery backed SRAM */
 924                 .nvram_offset   = 0x20,
 925                 .nvram_size     = 4,    /* 32bit (4 word x 8 bit) */
 926                 .offset         = 0x10,
 927                 .irq_handler = rx8130_irq,
 928                 .rtc_ops = &rx8130_rtc_ops,
 929         },
 930         [m41t0] = {
 931                 .rtc_ops        = &m41txx_rtc_ops,
 932         },
 933         [m41t00] = {
 934                 .rtc_ops        = &m41txx_rtc_ops,
 935         },
 936         [m41t11] = {
 937                 /* this is battery backed SRAM */
 938                 .nvram_offset   = 8,
 939                 .nvram_size     = 56,
 940                 .rtc_ops        = &m41txx_rtc_ops,
 941         },
 942         [mcp794xx] = {
 943                 .alarm          = 1,
 944                 /* this is battery backed SRAM */
 945                 .nvram_offset   = 0x20,
 946                 .nvram_size     = 0x40,
 947                 .irq_handler = mcp794xx_irq,
 948                 .rtc_ops = &mcp794xx_rtc_ops,
 949         },
 950 };
 951
 952 static const struct i2c_device_id ds1307_id[] = {
 953         { "ds1307", ds_1307 },
 954         { "ds1308", ds_1308 },
 955         { "ds1337", ds_1337 },
 956         { "ds1338", ds_1338 },
 957         { "ds1339", ds_1339 },
 958         { "ds1388", ds_1388 },
 959         { "ds1340", ds_1340 },
 960         { "ds1341", ds_1341 },
 961         { "ds3231", ds_3231 },
 962         { "m41t0", m41t0 },
 963         { "m41t00", m41t00 },
 964         { "m41t11", m41t11 },
 965         { "mcp7940x", mcp794xx },
 966         { "mcp7941x", mcp794xx },
 967         { "pt7c4338", ds_1307 },
 968         { "rx8025", rx_8025 },
 969         { "isl12057", ds_1337 },
 970         { "rx8130", rx_8130 },
 971         { }
 972 };
 973 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 974
 975 #ifdef CONFIG_OF
 976 static const struct of_device_id ds1307_of_match[] = {
 977         {
 978                 .compatible = "dallas,ds1307",
 979                 .data = (void *)ds_1307
 980         },
 981         {
 982                 .compatible = "dallas,ds1308",
 983                 .data = (void *)ds_1308
 984         },
 985         {
 986                 .compatible = "dallas,ds1337",
 987                 .data = (void *)ds_1337
 988         },
 989         {
 990                 .compatible = "dallas,ds1338",
 991                 .data = (void *)ds_1338
 992         },
 993         {
 994                 .compatible = "dallas,ds1339",
 995                 .data = (void *)ds_1339
 996         },
 997         {
 998                 .compatible = "dallas,ds1388",
 999                 .data = (void *)ds_1388
1000         },
1001         {
1002                 .compatible = "dallas,ds1340",
1003                 .data = (void *)ds_1340
1004         },
1005         {
1006                 .compatible = "dallas,ds1341",
1007                 .data = (void *)ds_1341
1008         },
1009         {
1010                 .compatible = "maxim,ds3231",
1011                 .data = (void *)ds_3231
1012         },
1013         {
1014                 .compatible = "st,m41t0",
1015                 .data = (void *)m41t0
1016         },
1017         {
1018                 .compatible = "st,m41t00",
1019                 .data = (void *)m41t00
1020         },
1021         {
1022                 .compatible = "st,m41t11",
1023                 .data = (void *)m41t11
1024         },
1025         {
1026                 .compatible = "microchip,mcp7940x",
1027                 .data = (void *)mcp794xx
1028         },
1029         {
1030                 .compatible = "microchip,mcp7941x",
1031                 .data = (void *)mcp794xx
1032         },
1033         {
1034                 .compatible = "pericom,pt7c4338",
1035                 .data = (void *)ds_1307
1036         },
1037         {
1038                 .compatible = "epson,rx8025",
1039                 .data = (void *)rx_8025
1040         },
1041         {
1042                 .compatible = "isil,isl12057",
1043                 .data = (void *)ds_1337
1044         },
1045         {
1046                 .compatible = "epson,rx8130",
1047                 .data = (void *)rx_8130
1048         },
1049         { }
1050 };
1051 MODULE_DEVICE_TABLE(of, ds1307_of_match);
1052 #endif
1053
1054 #ifdef CONFIG_ACPI
1055 static const struct acpi_device_id ds1307_acpi_ids[] = {
1056         { .id = "DS1307", .driver_data = ds_1307 },
1057         { .id = "DS1308", .driver_data = ds_1308 },
1058         { .id = "DS1337", .driver_data = ds_1337 },
1059         { .id = "DS1338", .driver_data = ds_1338 },
1060         { .id = "DS1339", .driver_data = ds_1339 },
1061         { .id = "DS1388", .driver_data = ds_1388 },
1062         { .id = "DS1340", .driver_data = ds_1340 },
1063         { .id = "DS1341", .driver_data = ds_1341 },
1064         { .id = "DS3231", .driver_data = ds_3231 },
1065         { .id = "M41T0", .driver_data = m41t0 },
1066         { .id = "M41T00", .driver_data = m41t00 },
1067         { .id = "M41T11", .driver_data = m41t11 },
1068         { .id = "MCP7940X", .driver_data = mcp794xx },
1069         { .id = "MCP7941X", .driver_data = mcp794xx },
1070         { .id = "PT7C4338", .driver_data = ds_1307 },
1071         { .id = "RX8025", .driver_data = rx_8025 },
1072         { .id = "ISL12057", .driver_data = ds_1337 },
1073         { .id = "RX8130", .driver_data = rx_8130 },
1074         { }
1075 };
1076 MODULE_DEVICE_TABLE(acpi, ds1307_acpi_ids);
1077 #endif
1078
1079 /*
1080  * The ds1337 and ds1339 both have two alarms, but we only use the first
1081  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
1082  * signal; ds1339 chips have only one alarm signal.
1083  */
1084 static irqreturn_t ds1307_irq(int irq, void *dev_id)
1085 {
1086         struct ds1307           *ds1307 = dev_id;
1087         struct mutex            *lock = &ds1307->rtc->ops_lock;
1088         int                     stat, ret;
1089
1090         mutex_lock(lock);
1091         ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &stat);
1092         if (ret)
1093                 goto out;
1094
1095         if (stat & DS1337_BIT_A1I) {
1096                 stat &= ~DS1337_BIT_A1I;
1097                 regmap_write(ds1307->regmap, DS1337_REG_STATUS, stat);
1098
1099                 ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1100                                          DS1337_BIT_A1IE, 0);
1101                 if (ret)
1102                         goto out;
1103
1104                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
1105         }
1106
1107 out:
1108         mutex_unlock(lock);
1109
1110         return IRQ_HANDLED;
1111 }
1112
1113 /*----------------------------------------------------------------------*/
1114
1115 static const struct rtc_class_ops ds13xx_rtc_ops = {
1116         .read_time      = ds1307_get_time,
1117         .set_time       = ds1307_set_time,
1118         .read_alarm     = ds1337_read_alarm,
1119         .set_alarm      = ds1337_set_alarm,
1120         .alarm_irq_enable = ds1307_alarm_irq_enable,
1121 };
1122
1123 static ssize_t frequency_test_store(struct device *dev,
1124                                     struct device_attribute *attr,
1125                                     const char *buf, size_t count)
1126 {
1127         struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1128         bool freq_test_en;
1129         int ret;
1130
1131         ret = kstrtobool(buf, &freq_test_en);
1132         if (ret) {
1133                 dev_err(dev, "Failed to store RTC Frequency Test attribute\n");
1134                 return ret;
1135         }
1136
1137         regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL, M41TXX_BIT_FT,
1138                            freq_test_en ? M41TXX_BIT_FT : 0);
1139
1140         return count;
1141 }
1142
1143 static ssize_t frequency_test_show(struct device *dev,
1144                                    struct device_attribute *attr,
1145                                    char *buf)
1146 {
1147         struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1148         unsigned int ctrl_reg;
1149
1150         regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
1151
1152         return scnprintf(buf, PAGE_SIZE, (ctrl_reg & M41TXX_BIT_FT) ? "on\n" :
1153                         "off\n");
1154 }
1155
1156 static DEVICE_ATTR_RW(frequency_test);
1157
1158 static struct attribute *rtc_freq_test_attrs[] = {
1159         &dev_attr_frequency_test.attr,
1160         NULL,
1161 };
1162
1163 static const struct attribute_group rtc_freq_test_attr_group = {
1164         .attrs          = rtc_freq_test_attrs,
1165 };
1166
1167 static int ds1307_add_frequency_test(struct ds1307 *ds1307)
1168 {
1169         int err;
1170
1171         switch (ds1307->type) {
1172         case m41t0:
1173         case m41t00:
1174         case m41t11:
1175                 err = rtc_add_group(ds1307->rtc, &rtc_freq_test_attr_group);
1176                 if (err)
1177                         return err;
1178                 break;
1179         default:
1180                 break;
1181         }
1182
1183         return 0;
1184 }
1185
1186 /*----------------------------------------------------------------------*/
1187
1188 static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
1189                              size_t bytes)
1190 {
1191         struct ds1307 *ds1307 = priv;
1192         const struct chip_desc *chip = &chips[ds1307->type];
1193
1194         return regmap_bulk_read(ds1307->regmap, chip->nvram_offset + offset,
1195                                 val, bytes);
1196 }
1197
1198 static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
1199                               size_t bytes)
1200 {
1201         struct ds1307 *ds1307 = priv;
1202         const struct chip_desc *chip = &chips[ds1307->type];
1203
1204         return regmap_bulk_write(ds1307->regmap, chip->nvram_offset + offset,
1205                                  val, bytes);
1206 }
1207
1208 /*----------------------------------------------------------------------*/
1209
1210 static u8 ds1307_trickle_init(struct ds1307 *ds1307,
1211                               const struct chip_desc *chip)
1212 {
1213         u32 ohms;
1214         bool diode = true;
1215
1216         if (!chip->do_trickle_setup)
1217                 return 0;
1218
1219         if (device_property_read_u32(ds1307->dev, "trickle-resistor-ohms",
1220                                      &ohms))
1221                 return 0;
1222
1223         if (device_property_read_bool(ds1307->dev, "trickle-diode-disable"))
1224                 diode = false;
1225
1226         return chip->do_trickle_setup(ds1307, ohms, diode);
1227 }
1228
1229 /*----------------------------------------------------------------------*/
1230
1231 #if IS_REACHABLE(CONFIG_HWMON)
1232
1233 /*
1234  * Temperature sensor support for ds3231 devices.
1235  */
1236
1237 #define DS3231_REG_TEMPERATURE  0x11
1238
1239 /*
1240  * A user-initiated temperature conversion is not started by this function,
1241  * so the temperature is updated once every 64 seconds.
1242  */
1243 static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
1244 {
1245         struct ds1307 *ds1307 = dev_get_drvdata(dev);
1246         u8 temp_buf[2];
1247         s16 temp;
1248         int ret;
1249
1250         ret = regmap_bulk_read(ds1307->regmap, DS3231_REG_TEMPERATURE,
1251                                temp_buf, sizeof(temp_buf));
1252         if (ret)
1253                 return ret;
1254         /*
1255          * Temperature is represented as a 10-bit code with a resolution of
1256          * 0.25 degree celsius and encoded in two's complement format.
1257          */
1258         temp = (temp_buf[0] << 8) | temp_buf[1];
1259         temp >>= 6;
1260         *mC = temp * 250;
1261
1262         return 0;
1263 }
1264
1265 static ssize_t ds3231_hwmon_show_temp(struct device *dev,
1266                                       struct device_attribute *attr, char *buf)
1267 {
1268         int ret;
1269         s32 temp;
1270
1271         ret = ds3231_hwmon_read_temp(dev, &temp);
1272         if (ret)
1273                 return ret;
1274
1275         return sprintf(buf, "%d\n", temp);
1276 }
1277 static SENSOR_DEVICE_ATTR(temp1_input, 0444, ds3231_hwmon_show_temp,
1278                           NULL, 0);
1279
1280 static struct attribute *ds3231_hwmon_attrs[] = {
1281         &sensor_dev_attr_temp1_input.dev_attr.attr,
1282         NULL,
1283 };
1284 ATTRIBUTE_GROUPS(ds3231_hwmon);
1285
1286 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1287 {
1288         struct device *dev;
1289
1290         if (ds1307->type != ds_3231)
1291                 return;
1292
1293         dev = devm_hwmon_device_register_with_groups(ds1307->dev, ds1307->name,
1294                                                      ds1307,
1295                                                      ds3231_hwmon_groups);
1296         if (IS_ERR(dev)) {
1297                 dev_warn(ds1307->dev, "unable to register hwmon device %ld\n",
1298                          PTR_ERR(dev));
1299         }
1300 }
1301
1302 #else
1303
1304 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1305 {
1306 }
1307
1308 #endif /* CONFIG_RTC_DRV_DS1307_HWMON */
1309
1310 /*----------------------------------------------------------------------*/
1311
1312 /*
1313  * Square-wave output support for DS3231
1314  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1315  */
1316 #ifdef CONFIG_COMMON_CLK
1317
1318 enum {
1319         DS3231_CLK_SQW = 0,
1320         DS3231_CLK_32KHZ,
1321 };
1322
1323 #define clk_sqw_to_ds1307(clk)  \
1324         container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1325 #define clk_32khz_to_ds1307(clk)        \
1326         container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1327
1328 static int ds3231_clk_sqw_rates[] = {
1329         1,
1330         1024,
1331         4096,
1332         8192,
1333 };
1334
1335 static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1336 {
1337         struct mutex *lock = &ds1307->rtc->ops_lock;
1338         int ret;
1339
1340         mutex_lock(lock);
1341         ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1342                                  mask, value);
1343         mutex_unlock(lock);
1344
1345         return ret;
1346 }
1347
1348 static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1349                                                 unsigned long parent_rate)
1350 {
1351         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1352         int control, ret;
1353         int rate_sel = 0;
1354
1355         ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1356         if (ret)
1357                 return ret;
1358         if (control & DS1337_BIT_RS1)
1359                 rate_sel += 1;
1360         if (control & DS1337_BIT_RS2)
1361                 rate_sel += 2;
1362
1363         return ds3231_clk_sqw_rates[rate_sel];
1364 }
1365
1366 static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1367                                       unsigned long *prate)
1368 {
1369         int i;
1370
1371         for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1372                 if (ds3231_clk_sqw_rates[i] <= rate)
1373                         return ds3231_clk_sqw_rates[i];
1374         }
1375
1376         return 0;
1377 }
1378
1379 static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1380                                    unsigned long parent_rate)
1381 {
1382         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1383         int control = 0;
1384         int rate_sel;
1385
1386         for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1387                         rate_sel++) {
1388                 if (ds3231_clk_sqw_rates[rate_sel] == rate)
1389                         break;
1390         }
1391
1392         if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1393                 return -EINVAL;
1394
1395         if (rate_sel & 1)
1396                 control |= DS1337_BIT_RS1;
1397         if (rate_sel & 2)
1398                 control |= DS1337_BIT_RS2;
1399
1400         return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1401                                 control);
1402 }
1403
1404 static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1405 {
1406         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1407
1408         return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1409 }
1410
1411 static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1412 {
1413         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1414
1415         ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1416 }
1417
1418 static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1419 {
1420         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1421         int control, ret;
1422
1423         ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1424         if (ret)
1425                 return ret;
1426
1427         return !(control & DS1337_BIT_INTCN);
1428 }
1429
1430 static const struct clk_ops ds3231_clk_sqw_ops = {
1431         .prepare = ds3231_clk_sqw_prepare,
1432         .unprepare = ds3231_clk_sqw_unprepare,
1433         .is_prepared = ds3231_clk_sqw_is_prepared,
1434         .recalc_rate = ds3231_clk_sqw_recalc_rate,
1435         .round_rate = ds3231_clk_sqw_round_rate,
1436         .set_rate = ds3231_clk_sqw_set_rate,
1437 };
1438
1439 static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1440                                                   unsigned long parent_rate)
1441 {
1442         return 32768;
1443 }
1444
1445 static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1446 {
1447         struct mutex *lock = &ds1307->rtc->ops_lock;
1448         int ret;
1449
1450         mutex_lock(lock);
1451         ret = regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
1452                                  DS3231_BIT_EN32KHZ,
1453                                  enable ? DS3231_BIT_EN32KHZ : 0);
1454         mutex_unlock(lock);
1455
1456         return ret;
1457 }
1458
1459 static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1460 {
1461         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1462
1463         return ds3231_clk_32khz_control(ds1307, true);
1464 }
1465
1466 static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1467 {
1468         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1469
1470         ds3231_clk_32khz_control(ds1307, false);
1471 }
1472
1473 static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1474 {
1475         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1476         int status, ret;
1477
1478         ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &status);
1479         if (ret)
1480                 return ret;
1481
1482         return !!(status & DS3231_BIT_EN32KHZ);
1483 }
1484
1485 static const struct clk_ops ds3231_clk_32khz_ops = {
1486         .prepare = ds3231_clk_32khz_prepare,
1487         .unprepare = ds3231_clk_32khz_unprepare,
1488         .is_prepared = ds3231_clk_32khz_is_prepared,
1489         .recalc_rate = ds3231_clk_32khz_recalc_rate,
1490 };
1491
1492 static struct clk_init_data ds3231_clks_init[] = {
1493         [DS3231_CLK_SQW] = {
1494                 .name = "ds3231_clk_sqw",
1495                 .ops = &ds3231_clk_sqw_ops,
1496         },
1497         [DS3231_CLK_32KHZ] = {
1498                 .name = "ds3231_clk_32khz",
1499                 .ops = &ds3231_clk_32khz_ops,
1500         },
1501 };
1502
1503 static int ds3231_clks_register(struct ds1307 *ds1307)
1504 {
1505         struct device_node *node = ds1307->dev->of_node;
1506         struct clk_onecell_data *onecell;
1507         int i;
1508
1509         onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
1510         if (!onecell)
1511                 return -ENOMEM;
1512
1513         onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1514         onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
1515                                      sizeof(onecell->clks[0]), GFP_KERNEL);
1516         if (!onecell->clks)
1517                 return -ENOMEM;
1518
1519         for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1520                 struct clk_init_data init = ds3231_clks_init[i];
1521
1522                 /*
1523                  * Interrupt signal due to alarm conditions and square-wave
1524                  * output share same pin, so don't initialize both.
1525                  */
1526                 if (i == DS3231_CLK_SQW && test_bit(HAS_ALARM, &ds1307->flags))
1527                         continue;
1528
1529                 /* optional override of the clockname */
1530                 of_property_read_string_index(node, "clock-output-names", i,
1531                                               &init.name);
1532                 ds1307->clks[i].init = &init;
1533
1534                 onecell->clks[i] = devm_clk_register(ds1307->dev,
1535                                                      &ds1307->clks[i]);
1536                 if (IS_ERR(onecell->clks[i]))
1537                         return PTR_ERR(onecell->clks[i]);
1538         }
1539
1540         if (!node)
1541                 return 0;
1542
1543         of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1544
1545         return 0;
1546 }
1547
1548 static void ds1307_clks_register(struct ds1307 *ds1307)
1549 {
1550         int ret;
1551
1552         if (ds1307->type != ds_3231)
1553                 return;
1554
1555         ret = ds3231_clks_register(ds1307);
1556         if (ret) {
1557                 dev_warn(ds1307->dev, "unable to register clock device %d\n",
1558                          ret);
1559         }
1560 }
1561
1562 #else
1563
1564 static void ds1307_clks_register(struct ds1307 *ds1307)
1565 {
1566 }
1567
1568 #endif /* CONFIG_COMMON_CLK */
1569
1570 static const struct regmap_config regmap_config = {
1571         .reg_bits = 8,
1572         .val_bits = 8,
1573 };
1574
1575 static int ds1307_probe(struct i2c_client *client,
1576                         const struct i2c_device_id *id)
1577 {
1578         struct ds1307           *ds1307;
1579         int                     err = -ENODEV;
1580         int                     tmp;
1581         const struct chip_desc  *chip;
1582         bool                    want_irq;
1583         bool                    ds1307_can_wakeup_device = false;
1584         unsigned char           regs[8];
1585         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1586         u8                      trickle_charger_setup = 0;
1587
1588         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1589         if (!ds1307)
1590                 return -ENOMEM;
1591
1592         dev_set_drvdata(&client->dev, ds1307);
1593         ds1307->dev = &client->dev;
1594         ds1307->name = client->name;
1595
1596         ds1307->regmap = devm_regmap_init_i2c(client, &regmap_config);
1597         if (IS_ERR(ds1307->regmap)) {
1598                 dev_err(ds1307->dev, "regmap allocation failed\n");
1599                 return PTR_ERR(ds1307->regmap);
1600         }
1601
1602         i2c_set_clientdata(client, ds1307);
1603
1604         if (client->dev.of_node) {
1605                 ds1307->type = (enum ds_type)
1606                         of_device_get_match_data(&client->dev);
1607                 chip = &chips[ds1307->type];
1608         } else if (id) {
1609                 chip = &chips[id->driver_data];
1610                 ds1307->type = id->driver_data;
1611         } else {
1612                 const struct acpi_device_id *acpi_id;
1613
1614                 acpi_id = acpi_match_device(ACPI_PTR(ds1307_acpi_ids),
1615                                             ds1307->dev);
1616                 if (!acpi_id)
1617                         return -ENODEV;
1618                 chip = &chips[acpi_id->driver_data];
1619                 ds1307->type = acpi_id->driver_data;
1620         }
1621
1622         want_irq = client->irq > 0 && chip->alarm;
1623
1624         if (!pdata)
1625                 trickle_charger_setup = ds1307_trickle_init(ds1307, chip);
1626         else if (pdata->trickle_charger_setup)
1627                 trickle_charger_setup = pdata->trickle_charger_setup;
1628
1629         if (trickle_charger_setup && chip->trickle_charger_reg) {
1630                 trickle_charger_setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
1631                 dev_dbg(ds1307->dev,
1632                         "writing trickle charger info 0x%x to 0x%x\n",
1633                         trickle_charger_setup, chip->trickle_charger_reg);
1634                 regmap_write(ds1307->regmap, chip->trickle_charger_reg,
1635                              trickle_charger_setup);
1636         }
1637
1638 #ifdef CONFIG_OF
1639 /*
1640  * For devices with no IRQ directly connected to the SoC, the RTC chip
1641  * can be forced as a wakeup source by stating that explicitly in
1642  * the device's .dts file using the "wakeup-source" boolean property.
1643  * If the "wakeup-source" property is set, don't request an IRQ.
1644  * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1645  * if supported by the RTC.
1646  */
1647         if (chip->alarm && of_property_read_bool(client->dev.of_node,
1648                                                  "wakeup-source"))
1649                 ds1307_can_wakeup_device = true;
1650 #endif
1651
1652         switch (ds1307->type) {
1653         case ds_1337:
1654         case ds_1339:
1655         case ds_1341:
1656         case ds_3231:
1657                 /* get registers that the "rtc" read below won't read... */
1658                 err = regmap_bulk_read(ds1307->regmap, DS1337_REG_CONTROL,
1659                                        regs, 2);
1660                 if (err) {
1661                         dev_dbg(ds1307->dev, "read error %d\n", err);
1662                         goto exit;
1663                 }
1664
1665                 /* oscillator off?  turn it on, so clock can tick. */
1666                 if (regs[0] & DS1337_BIT_nEOSC)
1667                         regs[0] &= ~DS1337_BIT_nEOSC;
1668
1669                 /*
1670                  * Using IRQ or defined as wakeup-source?
1671                  * Disable the square wave and both alarms.
1672                  * For some variants, be sure alarms can trigger when we're
1673                  * running on Vbackup (BBSQI/BBSQW)
1674                  */
1675                 if (want_irq || ds1307_can_wakeup_device) {
1676                         regs[0] |= DS1337_BIT_INTCN | chip->bbsqi_bit;
1677                         regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1678                 }
1679
1680                 regmap_write(ds1307->regmap, DS1337_REG_CONTROL,
1681                              regs[0]);
1682
1683                 /* oscillator fault?  clear flag, and warn */
1684                 if (regs[1] & DS1337_BIT_OSF) {
1685                         regmap_write(ds1307->regmap, DS1337_REG_STATUS,
1686                                      regs[1] & ~DS1337_BIT_OSF);
1687                         dev_warn(ds1307->dev, "SET TIME!\n");
1688                 }
1689                 break;
1690
1691         case rx_8025:
1692                 err = regmap_bulk_read(ds1307->regmap,
1693                                        RX8025_REG_CTRL1 << 4 | 0x08, regs, 2);
1694                 if (err) {
1695                         dev_dbg(ds1307->dev, "read error %d\n", err);
1696                         goto exit;
1697                 }
1698
1699                 /* oscillator off?  turn it on, so clock can tick. */
1700                 if (!(regs[1] & RX8025_BIT_XST)) {
1701                         regs[1] |= RX8025_BIT_XST;
1702                         regmap_write(ds1307->regmap,
1703                                      RX8025_REG_CTRL2 << 4 | 0x08,
1704                                      regs[1]);
1705                         dev_warn(ds1307->dev,
1706                                  "oscillator stop detected - SET TIME!\n");
1707                 }
1708
1709                 if (regs[1] & RX8025_BIT_PON) {
1710                         regs[1] &= ~RX8025_BIT_PON;
1711                         regmap_write(ds1307->regmap,
1712                                      RX8025_REG_CTRL2 << 4 | 0x08,
1713                                      regs[1]);
1714                         dev_warn(ds1307->dev, "power-on detected\n");
1715                 }
1716
1717                 if (regs[1] & RX8025_BIT_VDET) {
1718                         regs[1] &= ~RX8025_BIT_VDET;
1719                         regmap_write(ds1307->regmap,
1720                                      RX8025_REG_CTRL2 << 4 | 0x08,
1721                                      regs[1]);
1722                         dev_warn(ds1307->dev, "voltage drop detected\n");
1723                 }
1724
1725                 /* make sure we are running in 24hour mode */
1726                 if (!(regs[0] & RX8025_BIT_2412)) {
1727                         u8 hour;
1728
1729                         /* switch to 24 hour mode */
1730                         regmap_write(ds1307->regmap,
1731                                      RX8025_REG_CTRL1 << 4 | 0x08,
1732                                      regs[0] | RX8025_BIT_2412);
1733
1734                         err = regmap_bulk_read(ds1307->regmap,
1735                                                RX8025_REG_CTRL1 << 4 | 0x08,
1736                                                regs, 2);
1737                         if (err) {
1738                                 dev_dbg(ds1307->dev, "read error %d\n", err);
1739                                 goto exit;
1740                         }
1741
1742                         /* correct hour */
1743                         hour = bcd2bin(regs[DS1307_REG_HOUR]);
1744                         if (hour == 12)
1745                                 hour = 0;
1746                         if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1747                                 hour += 12;
1748
1749                         regmap_write(ds1307->regmap,
1750                                      DS1307_REG_HOUR << 4 | 0x08, hour);
1751                 }
1752                 break;
1753         default:
1754                 break;
1755         }
1756
1757         /* read RTC registers */
1758         err = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
1759                                sizeof(regs));
1760         if (err) {
1761                 dev_dbg(ds1307->dev, "read error %d\n", err);
1762                 goto exit;
1763         }
1764
1765         if (ds1307->type == mcp794xx &&
1766             !(regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1767                 regmap_write(ds1307->regmap, DS1307_REG_WDAY,
1768                              regs[DS1307_REG_WDAY] |
1769                              MCP794XX_BIT_VBATEN);
1770         }
1771
1772         tmp = regs[DS1307_REG_HOUR];
1773         switch (ds1307->type) {
1774         case ds_1340:
1775         case m41t0:
1776         case m41t00:
1777         case m41t11:
1778                 /*
1779                  * NOTE: ignores century bits; fix before deploying
1780                  * systems that will run through year 2100.
1781                  */
1782                 break;
1783         case rx_8025:
1784                 break;
1785         default:
1786                 if (!(tmp & DS1307_BIT_12HR))
1787                         break;
1788
1789                 /*
1790                  * Be sure we're in 24 hour mode.  Multi-master systems
1791                  * take note...
1792                  */
1793                 tmp = bcd2bin(tmp & 0x1f);
1794                 if (tmp == 12)
1795                         tmp = 0;
1796                 if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1797                         tmp += 12;
1798                 regmap_write(ds1307->regmap, chip->offset + DS1307_REG_HOUR,
1799                              bin2bcd(tmp));
1800         }
1801
1802         if (want_irq || ds1307_can_wakeup_device) {
1803                 device_set_wakeup_capable(ds1307->dev, true);
1804                 set_bit(HAS_ALARM, &ds1307->flags);
1805         }
1806
1807         ds1307->rtc = devm_rtc_allocate_device(ds1307->dev);
1808         if (IS_ERR(ds1307->rtc))
1809                 return PTR_ERR(ds1307->rtc);
1810
1811         if (ds1307_can_wakeup_device && !want_irq) {
1812                 dev_info(ds1307->dev,
1813                          "'wakeup-source' is set, request for an IRQ is disabled!\n");
1814                 /* We cannot support UIE mode if we do not have an IRQ line */
1815                 ds1307->rtc->uie_unsupported = 1;
1816         }
1817
1818         if (want_irq) {
1819                 err = devm_request_threaded_irq(ds1307->dev, client->irq, NULL,
1820                                                 chip->irq_handler ?: ds1307_irq,
1821                                                 IRQF_SHARED | IRQF_ONESHOT,
1822                                                 ds1307->name, ds1307);
1823                 if (err) {
1824                         client->irq = 0;
1825                         device_set_wakeup_capable(ds1307->dev, false);
1826                         clear_bit(HAS_ALARM, &ds1307->flags);
1827                         dev_err(ds1307->dev, "unable to request IRQ!\n");
1828                 } else {
1829                         dev_dbg(ds1307->dev, "got IRQ %d\n", client->irq);
1830                 }
1831         }
1832
1833         ds1307->rtc->ops = chip->rtc_ops ?: &ds13xx_rtc_ops;
1834         err = ds1307_add_frequency_test(ds1307);
1835         if (err)
1836                 return err;
1837
1838         err = rtc_register_device(ds1307->rtc);
1839         if (err)
1840                 return err;
1841
1842         if (chip->nvram_size) {
1843                 struct nvmem_config nvmem_cfg = {
1844                         .name = "ds1307_nvram",
1845                         .word_size = 1,
1846                         .stride = 1,
1847                         .size = chip->nvram_size,
1848                         .reg_read = ds1307_nvram_read,
1849                         .reg_write = ds1307_nvram_write,
1850                         .priv = ds1307,
1851                 };
1852
1853                 ds1307->rtc->nvram_old_abi = true;
1854                 rtc_nvmem_register(ds1307->rtc, &nvmem_cfg);
1855         }
1856
1857         ds1307_hwmon_register(ds1307);
1858         ds1307_clks_register(ds1307);
1859
1860         return 0;
1861
1862 exit:
1863         return err;
1864 }
1865
1866 static struct i2c_driver ds1307_driver = {
1867         .driver = {
1868                 .name   = "rtc-ds1307",
1869                 .of_match_table = of_match_ptr(ds1307_of_match),
1870                 .acpi_match_table = ACPI_PTR(ds1307_acpi_ids),
1871         },
1872         .probe          = ds1307_probe,
1873         .id_table       = ds1307_id,
1874 };
1875
1876 module_i2c_driver(ds1307_driver);
1877
1878 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1879 MODULE_LICENSE("GPL");