drivers/rtc/rtc-rs5c372.c

   1 /*
   2  * An I2C driver for Ricoh RS5C372, R2025S/D and RV5C38[67] RTCs
   3  *
   4  * Copyright (C) 2005 Pavel Mironchik <pmironchik@optifacio.net>
   5  * Copyright (C) 2006 Tower Technologies
   6  * Copyright (C) 2008 Paul Mundt
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/i2c.h>
  14 #include <linux/rtc.h>
  15 #include <linux/bcd.h>
  16 #include <linux/slab.h>
  17 #include <linux/module.h>
  18
  19 /*
  20  * Ricoh has a family of I2C based RTCs, which differ only slightly from
  21  * each other.  Differences center on pinout (e.g. how many interrupts,
  22  * output clock, etc) and how the control registers are used.  The '372
  23  * is significant only because that's the one this driver first supported.
  24  */
  25 #define RS5C372_REG_SECS        0
  26 #define RS5C372_REG_MINS        1
  27 #define RS5C372_REG_HOURS       2
  28 #define RS5C372_REG_WDAY        3
  29 #define RS5C372_REG_DAY         4
  30 #define RS5C372_REG_MONTH       5
  31 #define RS5C372_REG_YEAR        6
  32 #define RS5C372_REG_TRIM        7
  33 #       define RS5C372_TRIM_XSL         0x80
  34 #       define RS5C372_TRIM_MASK        0x7F
  35
  36 #define RS5C_REG_ALARM_A_MIN    8                       /* or ALARM_W */
  37 #define RS5C_REG_ALARM_A_HOURS  9
  38 #define RS5C_REG_ALARM_A_WDAY   10
  39
  40 #define RS5C_REG_ALARM_B_MIN    11                      /* or ALARM_D */
  41 #define RS5C_REG_ALARM_B_HOURS  12
  42 #define RS5C_REG_ALARM_B_WDAY   13                      /* (ALARM_B only) */
  43
  44 #define RS5C_REG_CTRL1          14
  45 #       define RS5C_CTRL1_AALE          (1 << 7)        /* or WALE */
  46 #       define RS5C_CTRL1_BALE          (1 << 6)        /* or DALE */
  47 #       define RV5C387_CTRL1_24         (1 << 5)
  48 #       define RS5C372A_CTRL1_SL1       (1 << 5)
  49 #       define RS5C_CTRL1_CT_MASK       (7 << 0)
  50 #       define RS5C_CTRL1_CT0           (0 << 0)        /* no periodic irq */
  51 #       define RS5C_CTRL1_CT4           (4 << 0)        /* 1 Hz level irq */
  52 #define RS5C_REG_CTRL2          15
  53 #       define RS5C372_CTRL2_24         (1 << 5)
  54 #       define R2025_CTRL2_XST          (1 << 5)
  55 #       define RS5C_CTRL2_XSTP          (1 << 4)        /* only if !R2025S/D */
  56 #       define RS5C_CTRL2_CTFG          (1 << 2)
  57 #       define RS5C_CTRL2_AAFG          (1 << 1)        /* or WAFG */
  58 #       define RS5C_CTRL2_BAFG          (1 << 0)        /* or DAFG */
  59
  60
  61 /* to read (style 1) or write registers starting at R */
  62 #define RS5C_ADDR(R)            (((R) << 4) | 0)
  63
  64
  65 enum rtc_type {
  66         rtc_undef = 0,
  67         rtc_r2025sd,
  68         rtc_r2221tl,
  69         rtc_rs5c372a,
  70         rtc_rs5c372b,
  71         rtc_rv5c386,
  72         rtc_rv5c387a,
  73 };
  74
  75 static const struct i2c_device_id rs5c372_id[] = {
  76         { "r2025sd", rtc_r2025sd },
  77         { "r2221tl", rtc_r2221tl },
  78         { "rs5c372a", rtc_rs5c372a },
  79         { "rs5c372b", rtc_rs5c372b },
  80         { "rv5c386", rtc_rv5c386 },
  81         { "rv5c387a", rtc_rv5c387a },
  82         { }
  83 };
  84 MODULE_DEVICE_TABLE(i2c, rs5c372_id);
  85
  86 /* REVISIT:  this assumes that:
  87  *  - we're in the 21st century, so it's safe to ignore the century
  88  *    bit for rv5c38[67] (REG_MONTH bit 7);
  89  *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
  90  */
  91 struct rs5c372 {
  92         struct i2c_client       *client;
  93         struct rtc_device       *rtc;
  94         enum rtc_type           type;
  95         unsigned                time24:1;
  96         unsigned                has_irq:1;
  97         unsigned                smbus:1;
  98         char                    buf[17];
  99         char                    *regs;
 100 };
 101
 102 static int rs5c_get_regs(struct rs5c372 *rs5c)
 103 {
 104         struct i2c_client       *client = rs5c->client;
 105         struct i2c_msg          msgs[] = {
 106                 {
 107                         .addr = client->addr,
 108                         .flags = I2C_M_RD,
 109                         .len = sizeof(rs5c->buf),
 110                         .buf = rs5c->buf
 111                 },
 112         };
 113
 114         /* This implements the third reading method from the datasheet, using
 115          * an internal address that's reset after each transaction (by STOP)
 116          * to 0x0f ... so we read extra registers, and skip the first one.
 117          *
 118          * The first method doesn't work with the iop3xx adapter driver, on at
 119          * least 80219 chips; this works around that bug.
 120          *
 121          * The third method on the other hand doesn't work for the SMBus-only
 122          * configurations, so we use the the first method there, stripping off
 123          * the extra register in the process.
 124          */
 125         if (rs5c->smbus) {
 126                 int addr = RS5C_ADDR(RS5C372_REG_SECS);
 127                 int size = sizeof(rs5c->buf) - 1;
 128
 129                 if (i2c_smbus_read_i2c_block_data(client, addr, size,
 130                                                   rs5c->buf + 1) != size) {
 131                         dev_warn(&client->dev, "can't read registers\n");
 132                         return -EIO;
 133                 }
 134         } else {
 135                 if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
 136                         dev_warn(&client->dev, "can't read registers\n");
 137                         return -EIO;
 138                 }
 139         }
 140
 141         dev_dbg(&client->dev,
 142                 "%3ph (%02x) %3ph (%02x), %3ph, %3ph; %02x %02x\n",
 143                 rs5c->regs + 0, rs5c->regs[3],
 144                 rs5c->regs + 4, rs5c->regs[7],
 145                 rs5c->regs + 8, rs5c->regs + 11,
 146                 rs5c->regs[14], rs5c->regs[15]);
 147
 148         return 0;
 149 }
 150
 151 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
 152 {
 153         unsigned        hour;
 154
 155         if (rs5c->time24)
 156                 return bcd2bin(reg & 0x3f);
 157
 158         hour = bcd2bin(reg & 0x1f);
 159         if (hour == 12)
 160                 hour = 0;
 161         if (reg & 0x20)
 162                 hour += 12;
 163         return hour;
 164 }
 165
 166 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
 167 {
 168         if (rs5c->time24)
 169                 return bin2bcd(hour);
 170
 171         if (hour > 12)
 172                 return 0x20 | bin2bcd(hour - 12);
 173         if (hour == 12)
 174                 return 0x20 | bin2bcd(12);
 175         if (hour == 0)
 176                 return bin2bcd(12);
 177         return bin2bcd(hour);
 178 }
 179
 180 static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 181 {
 182         struct rs5c372  *rs5c = i2c_get_clientdata(client);
 183         int             status = rs5c_get_regs(rs5c);
 184
 185         if (status < 0)
 186                 return status;
 187
 188         tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
 189         tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
 190         tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
 191
 192         tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
 193         tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
 194
 195         /* tm->tm_mon is zero-based */
 196         tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
 197
 198         /* year is 1900 + tm->tm_year */
 199         tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
 200
 201         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 202                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 203                 __func__,
 204                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 205                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 206
 207         /* rtc might need initialization */
 208         return rtc_valid_tm(tm);
 209 }
 210
 211 static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 212 {
 213         struct rs5c372  *rs5c = i2c_get_clientdata(client);
 214         unsigned char   buf[7];
 215         int             addr;
 216
 217         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
 218                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 219                 __func__,
 220                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 221                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 222
 223         addr   = RS5C_ADDR(RS5C372_REG_SECS);
 224         buf[0] = bin2bcd(tm->tm_sec);
 225         buf[1] = bin2bcd(tm->tm_min);
 226         buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
 227         buf[3] = bin2bcd(tm->tm_wday);
 228         buf[4] = bin2bcd(tm->tm_mday);
 229         buf[5] = bin2bcd(tm->tm_mon + 1);
 230         buf[6] = bin2bcd(tm->tm_year - 100);
 231
 232         if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
 233                 dev_err(&client->dev, "%s: write error\n", __func__);
 234                 return -EIO;
 235         }
 236
 237         return 0;
 238 }
 239
 240 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 241 #define NEED_TRIM
 242 #endif
 243
 244 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
 245 #define NEED_TRIM
 246 #endif
 247
 248 #ifdef  NEED_TRIM
 249 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
 250 {
 251         struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
 252         u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
 253
 254         if (osc)
 255                 *osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
 256
 257         if (trim) {
 258                 dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
 259                 tmp &= RS5C372_TRIM_MASK;
 260                 if (tmp & 0x3e) {
 261                         int t = tmp & 0x3f;
 262
 263                         if (tmp & 0x40)
 264                                 t = (~t | (s8)0xc0) + 1;
 265                         else
 266                                 t = t - 1;
 267
 268                         tmp = t * 2;
 269                 } else
 270                         tmp = 0;
 271                 *trim = tmp;
 272         }
 273
 274         return 0;
 275 }
 276 #endif
 277
 278 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
 279 {
 280         return rs5c372_get_datetime(to_i2c_client(dev), tm);
 281 }
 282
 283 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
 284 {
 285         return rs5c372_set_datetime(to_i2c_client(dev), tm);
 286 }
 287
 288
 289 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 290 {
 291         struct i2c_client       *client = to_i2c_client(dev);
 292         struct rs5c372          *rs5c = i2c_get_clientdata(client);
 293         unsigned char           buf;
 294         int                     status, addr;
 295
 296         buf = rs5c->regs[RS5C_REG_CTRL1];
 297
 298         if (!rs5c->has_irq)
 299                 return -EINVAL;
 300
 301         status = rs5c_get_regs(rs5c);
 302         if (status < 0)
 303                 return status;
 304
 305         addr = RS5C_ADDR(RS5C_REG_CTRL1);
 306         if (enabled)
 307                 buf |= RS5C_CTRL1_AALE;
 308         else
 309                 buf &= ~RS5C_CTRL1_AALE;
 310
 311         if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
 312                 dev_warn(dev, "can't update alarm\n");
 313                 status = -EIO;
 314         } else
 315                 rs5c->regs[RS5C_REG_CTRL1] = buf;
 316
 317         return status;
 318 }
 319
 320
 321 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
 322  * which only exposes a polled programming interface; and since
 323  * these calls map directly to those EFI requests; we don't demand
 324  * we have an IRQ for this chip when we go through this API.
 325  *
 326  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
 327  * though, managed through RTC_AIE_{ON,OFF} requests.
 328  */
 329
 330 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 331 {
 332         struct i2c_client       *client = to_i2c_client(dev);
 333         struct rs5c372          *rs5c = i2c_get_clientdata(client);
 334         int                     status;
 335
 336         status = rs5c_get_regs(rs5c);
 337         if (status < 0)
 338                 return status;
 339
 340         /* report alarm time */
 341         t->time.tm_sec = 0;
 342         t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
 343         t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
 344
 345         /* ... and status */
 346         t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
 347         t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
 348
 349         return 0;
 350 }
 351
 352 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 353 {
 354         struct i2c_client       *client = to_i2c_client(dev);
 355         struct rs5c372          *rs5c = i2c_get_clientdata(client);
 356         int                     status, addr, i;
 357         unsigned char           buf[3];
 358
 359         /* only handle up to 24 hours in the future, like RTC_ALM_SET */
 360         if (t->time.tm_mday != -1
 361                         || t->time.tm_mon != -1
 362                         || t->time.tm_year != -1)
 363                 return -EINVAL;
 364
 365         /* REVISIT: round up tm_sec */
 366
 367         /* if needed, disable irq (clears pending status) */
 368         status = rs5c_get_regs(rs5c);
 369         if (status < 0)
 370                 return status;
 371         if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
 372                 addr = RS5C_ADDR(RS5C_REG_CTRL1);
 373                 buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
 374                 if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
 375                         dev_dbg(dev, "can't disable alarm\n");
 376                         return -EIO;
 377                 }
 378                 rs5c->regs[RS5C_REG_CTRL1] = buf[0];
 379         }
 380
 381         /* set alarm */
 382         buf[0] = bin2bcd(t->time.tm_min);
 383         buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
 384         buf[2] = 0x7f;  /* any/all days */
 385
 386         for (i = 0; i < sizeof(buf); i++) {
 387                 addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
 388                 if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
 389                         dev_dbg(dev, "can't set alarm time\n");
 390                         return -EIO;
 391                 }
 392         }
 393
 394         /* ... and maybe enable its irq */
 395         if (t->enabled) {
 396                 addr = RS5C_ADDR(RS5C_REG_CTRL1);
 397                 buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
 398                 if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
 399                         dev_warn(dev, "can't enable alarm\n");
 400                 rs5c->regs[RS5C_REG_CTRL1] = buf[0];
 401         }
 402
 403         return 0;
 404 }
 405
 406 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 407
 408 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
 409 {
 410         int err, osc, trim;
 411
 412         err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
 413         if (err == 0) {
 414                 seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
 415                                 osc / 1000, osc % 1000);
 416                 seq_printf(seq, "trim\t\t: %d\n", trim);
 417         }
 418
 419         return 0;
 420 }
 421
 422 #else
 423 #define rs5c372_rtc_proc        NULL
 424 #endif
 425
 426 static const struct rtc_class_ops rs5c372_rtc_ops = {
 427         .proc           = rs5c372_rtc_proc,
 428         .read_time      = rs5c372_rtc_read_time,
 429         .set_time       = rs5c372_rtc_set_time,
 430         .read_alarm     = rs5c_read_alarm,
 431         .set_alarm      = rs5c_set_alarm,
 432         .alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
 433 };
 434
 435 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
 436
 437 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
 438                                 struct device_attribute *attr, char *buf)
 439 {
 440         int err, trim;
 441
 442         err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
 443         if (err)
 444                 return err;
 445
 446         return sprintf(buf, "%d\n", trim);
 447 }
 448 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
 449
 450 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
 451                                 struct device_attribute *attr, char *buf)
 452 {
 453         int err, osc;
 454
 455         err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
 456         if (err)
 457                 return err;
 458
 459         return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
 460 }
 461 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
 462
 463 static int rs5c_sysfs_register(struct device *dev)
 464 {
 465         int err;
 466
 467         err = device_create_file(dev, &dev_attr_trim);
 468         if (err)
 469                 return err;
 470         err = device_create_file(dev, &dev_attr_osc);
 471         if (err)
 472                 device_remove_file(dev, &dev_attr_trim);
 473
 474         return err;
 475 }
 476
 477 static void rs5c_sysfs_unregister(struct device *dev)
 478 {
 479         device_remove_file(dev, &dev_attr_trim);
 480         device_remove_file(dev, &dev_attr_osc);
 481 }
 482
 483 #else
 484 static int rs5c_sysfs_register(struct device *dev)
 485 {
 486         return 0;
 487 }
 488
 489 static void rs5c_sysfs_unregister(struct device *dev)
 490 {
 491         /* nothing */
 492 }
 493 #endif  /* SYSFS */
 494
 495 static struct i2c_driver rs5c372_driver;
 496
 497 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
 498 {
 499         unsigned char buf[2];
 500         int addr, i, ret = 0;
 501
 502         if (rs5c372->type == rtc_r2025sd) {
 503                 if (rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST)
 504                         return ret;
 505                 rs5c372->regs[RS5C_REG_CTRL2] |= R2025_CTRL2_XST;
 506         } else {
 507                 if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
 508                         return ret;
 509                 rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
 510         }
 511
 512         addr   = RS5C_ADDR(RS5C_REG_CTRL1);
 513         buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
 514         buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
 515
 516         /* use 24hr mode */
 517         switch (rs5c372->type) {
 518         case rtc_rs5c372a:
 519         case rtc_rs5c372b:
 520                 buf[1] |= RS5C372_CTRL2_24;
 521                 rs5c372->time24 = 1;
 522                 break;
 523         case rtc_r2025sd:
 524         case rtc_r2221tl:
 525         case rtc_rv5c386:
 526         case rtc_rv5c387a:
 527                 buf[0] |= RV5C387_CTRL1_24;
 528                 rs5c372->time24 = 1;
 529                 break;
 530         default:
 531                 /* impossible */
 532                 break;
 533         }
 534
 535         for (i = 0; i < sizeof(buf); i++) {
 536                 addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
 537                 ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
 538                 if (unlikely(ret < 0))
 539                         return ret;
 540         }
 541
 542         rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
 543         rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
 544
 545         return 0;
 546 }
 547
 548 static int rs5c372_probe(struct i2c_client *client,
 549                          const struct i2c_device_id *id)
 550 {
 551         int err = 0;
 552         int smbus_mode = 0;
 553         struct rs5c372 *rs5c372;
 554         struct rtc_time tm;
 555
 556         dev_dbg(&client->dev, "%s\n", __func__);
 557
 558         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 559                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 560                 /*
 561                  * If we don't have any master mode adapter, try breaking
 562                  * it down in to the barest of capabilities.
 563                  */
 564                 if (i2c_check_functionality(client->adapter,
 565                                 I2C_FUNC_SMBUS_BYTE_DATA |
 566                                 I2C_FUNC_SMBUS_I2C_BLOCK))
 567                         smbus_mode = 1;
 568                 else {
 569                         /* Still no good, give up */
 570                         err = -ENODEV;
 571                         goto exit;
 572                 }
 573         }
 574
 575         rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
 576                                 GFP_KERNEL);
 577         if (!rs5c372) {
 578                 err = -ENOMEM;
 579                 goto exit;
 580         }
 581
 582         rs5c372->client = client;
 583         i2c_set_clientdata(client, rs5c372);
 584         rs5c372->type = id->driver_data;
 585
 586         /* we read registers 0x0f then 0x00-0x0f; skip the first one */
 587         rs5c372->regs = &rs5c372->buf[1];
 588         rs5c372->smbus = smbus_mode;
 589
 590         err = rs5c_get_regs(rs5c372);
 591         if (err < 0)
 592                 goto exit;
 593
 594         /* clock may be set for am/pm or 24 hr time */
 595         switch (rs5c372->type) {
 596         case rtc_rs5c372a:
 597         case rtc_rs5c372b:
 598                 /* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
 599                  * so does periodic irq, except some 327a modes.
 600                  */
 601                 if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
 602                         rs5c372->time24 = 1;
 603                 break;
 604         case rtc_r2025sd:
 605         case rtc_r2221tl:
 606         case rtc_rv5c386:
 607         case rtc_rv5c387a:
 608                 if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
 609                         rs5c372->time24 = 1;
 610                 /* alarm uses ALARM_W; and nINTRB for alarm and periodic
 611                  * irq, on both 386 and 387
 612                  */
 613                 break;
 614         default:
 615                 dev_err(&client->dev, "unknown RTC type\n");
 616                 goto exit;
 617         }
 618
 619         /* if the oscillator lost power and no other software (like
 620          * the bootloader) set it up, do it here.
 621          *
 622          * The R2025S/D does this a little differently than the other
 623          * parts, so we special case that..
 624          */
 625         err = rs5c_oscillator_setup(rs5c372);
 626         if (unlikely(err < 0)) {
 627                 dev_err(&client->dev, "setup error\n");
 628                 goto exit;
 629         }
 630
 631         if (rs5c372_get_datetime(client, &tm) < 0)
 632                 dev_warn(&client->dev, "clock needs to be set\n");
 633
 634         dev_info(&client->dev, "%s found, %s\n",
 635                         ({ char *s; switch (rs5c372->type) {
 636                         case rtc_r2025sd:       s = "r2025sd"; break;
 637                         case rtc_r2221tl:       s = "r2221tl"; break;
 638                         case rtc_rs5c372a:      s = "rs5c372a"; break;
 639                         case rtc_rs5c372b:      s = "rs5c372b"; break;
 640                         case rtc_rv5c386:       s = "rv5c386"; break;
 641                         case rtc_rv5c387a:      s = "rv5c387a"; break;
 642                         default:                s = "chip"; break;
 643                         }; s;}),
 644                         rs5c372->time24 ? "24hr" : "am/pm"
 645                         );
 646
 647         /* REVISIT use client->irq to register alarm irq ... */
 648         rs5c372->rtc = devm_rtc_device_register(&client->dev,
 649                                         rs5c372_driver.driver.name,
 650                                         &rs5c372_rtc_ops, THIS_MODULE);
 651
 652         if (IS_ERR(rs5c372->rtc)) {
 653                 err = PTR_ERR(rs5c372->rtc);
 654                 goto exit;
 655         }
 656
 657         err = rs5c_sysfs_register(&client->dev);
 658         if (err)
 659                 goto exit;
 660
 661         return 0;
 662
 663 exit:
 664         return err;
 665 }
 666
 667 static int rs5c372_remove(struct i2c_client *client)
 668 {
 669         rs5c_sysfs_unregister(&client->dev);
 670         return 0;
 671 }
 672
 673 static struct i2c_driver rs5c372_driver = {
 674         .driver         = {
 675                 .name   = "rtc-rs5c372",
 676         },
 677         .probe          = rs5c372_probe,
 678         .remove         = rs5c372_remove,
 679         .id_table       = rs5c372_id,
 680 };
 681
 682 module_i2c_driver(rs5c372_driver);
 683
 684 MODULE_AUTHOR(
 685                 "Pavel Mironchik <pmironchik@optifacio.net>, "
 686                 "Alessandro Zummo <a.zummo@towertech.it>, "
 687                 "Paul Mundt <lethal@linux-sh.org>");
 688 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
 689 MODULE_LICENSE("GPL");