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 #include <linux/of_device.h>
  19
  20 /*
  21  * Ricoh has a family of I2C based RTCs, which differ only slightly from
  22  * each other.  Differences center on pinout (e.g. how many interrupts,
  23  * output clock, etc) and how the control registers are used.  The '372
  24  * is significant only because that's the one this driver first supported.
  25  */
  26 #define RS5C372_REG_SECS        0
  27 #define RS5C372_REG_MINS        1
  28 #define RS5C372_REG_HOURS       2
  29 #define RS5C372_REG_WDAY        3
  30 #define RS5C372_REG_DAY         4
  31 #define RS5C372_REG_MONTH       5
  32 #define RS5C372_REG_YEAR        6
  33 #define RS5C372_REG_TRIM        7
  34 #       define RS5C372_TRIM_XSL         0x80
  35 #       define RS5C372_TRIM_MASK        0x7F
  36
  37 #define RS5C_REG_ALARM_A_MIN    8                       /* or ALARM_W */
  38 #define RS5C_REG_ALARM_A_HOURS  9
  39 #define RS5C_REG_ALARM_A_WDAY   10
  40
  41 #define RS5C_REG_ALARM_B_MIN    11                      /* or ALARM_D */
  42 #define RS5C_REG_ALARM_B_HOURS  12
  43 #define RS5C_REG_ALARM_B_WDAY   13                      /* (ALARM_B only) */
  44
  45 #define RS5C_REG_CTRL1          14
  46 #       define RS5C_CTRL1_AALE          (1 << 7)        /* or WALE */
  47 #       define RS5C_CTRL1_BALE          (1 << 6)        /* or DALE */
  48 #       define RV5C387_CTRL1_24         (1 << 5)
  49 #       define RS5C372A_CTRL1_SL1       (1 << 5)
  50 #       define RS5C_CTRL1_CT_MASK       (7 << 0)
  51 #       define RS5C_CTRL1_CT0           (0 << 0)        /* no periodic irq */
  52 #       define RS5C_CTRL1_CT4           (4 << 0)        /* 1 Hz level irq */
  53 #define RS5C_REG_CTRL2          15
  54 #       define RS5C372_CTRL2_24         (1 << 5)
  55 #       define RS5C_CTRL2_XSTP          (1 << 4)        /* only if !R2x2x */
  56 #       define R2x2x_CTRL2_VDET         (1 << 6)        /* only if  R2x2x */
  57 #       define R2x2x_CTRL2_XSTP         (1 << 5)        /* only if  R2x2x */
  58 #       define R2x2x_CTRL2_PON          (1 << 4)        /* only if  R2x2x */
  59 #       define RS5C_CTRL2_CTFG          (1 << 2)
  60 #       define RS5C_CTRL2_AAFG          (1 << 1)        /* or WAFG */
  61 #       define RS5C_CTRL2_BAFG          (1 << 0)        /* or DAFG */
  62
  63
  64 /* to read (style 1) or write registers starting at R */
  65 #define RS5C_ADDR(R)            (((R) << 4) | 0)
  66
  67
  68 enum rtc_type {
  69         rtc_undef = 0,
  70         rtc_r2025sd,
  71         rtc_r2221tl,
  72         rtc_rs5c372a,
  73         rtc_rs5c372b,
  74         rtc_rv5c386,
  75         rtc_rv5c387a,
  76 };
  77
  78 static const struct i2c_device_id rs5c372_id[] = {
  79         { "r2025sd", rtc_r2025sd },
  80         { "r2221tl", rtc_r2221tl },
  81         { "rs5c372a", rtc_rs5c372a },
  82         { "rs5c372b", rtc_rs5c372b },
  83         { "rv5c386", rtc_rv5c386 },
  84         { "rv5c387a", rtc_rv5c387a },
  85         { }
  86 };
  87 MODULE_DEVICE_TABLE(i2c, rs5c372_id);
  88
  89 static const struct of_device_id rs5c372_of_match[] = {
  90         {
  91                 .compatible = "ricoh,r2025sd",
  92                 .data = (void *)rtc_r2025sd
  93         },
  94         {
  95                 .compatible = "ricoh,r2221tl",
  96                 .data = (void *)rtc_r2221tl
  97         },
  98         {
  99                 .compatible = "ricoh,rs5c372a",
 100                 .data = (void *)rtc_rs5c372a
 101         },
 102         {
 103                 .compatible = "ricoh,rs5c372b",
 104                 .data = (void *)rtc_rs5c372b
 105         },
 106         {
 107                 .compatible = "ricoh,rv5c386",
 108                 .data = (void *)rtc_rv5c386
 109         },
 110         {
 111                 .compatible = "ricoh,rv5c387a",
 112                 .data = (void *)rtc_rv5c387a
 113         },
 114         { }
 115 };
 116 MODULE_DEVICE_TABLE(of, rs5c372_of_match);
 117
 118 /* REVISIT:  this assumes that:
 119  *  - we're in the 21st century, so it's safe to ignore the century
 120  *    bit for rv5c38[67] (REG_MONTH bit 7);
 121  *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
 122  */
 123 struct rs5c372 {
 124         struct i2c_client       *client;
 125         struct rtc_device       *rtc;
 126         enum rtc_type           type;
 127         unsigned                time24:1;
 128         unsigned                has_irq:1;
 129         unsigned                smbus:1;
 130         char                    buf[17];
 131         char                    *regs;
 132 };
 133
 134 static int rs5c_get_regs(struct rs5c372 *rs5c)
 135 {
 136         struct i2c_client       *client = rs5c->client;
 137         struct i2c_msg          msgs[] = {
 138                 {
 139                         .addr = client->addr,
 140                         .flags = I2C_M_RD,
 141                         .len = sizeof(rs5c->buf),
 142                         .buf = rs5c->buf
 143                 },
 144         };
 145
 146         /* This implements the third reading method from the datasheet, using
 147          * an internal address that's reset after each transaction (by STOP)
 148          * to 0x0f ... so we read extra registers, and skip the first one.
 149          *
 150          * The first method doesn't work with the iop3xx adapter driver, on at
 151          * least 80219 chips; this works around that bug.
 152          *
 153          * The third method on the other hand doesn't work for the SMBus-only
 154          * configurations, so we use the the first method there, stripping off
 155          * the extra register in the process.
 156          */
 157         if (rs5c->smbus) {
 158                 int addr = RS5C_ADDR(RS5C372_REG_SECS);
 159                 int size = sizeof(rs5c->buf) - 1;
 160
 161                 if (i2c_smbus_read_i2c_block_data(client, addr, size,
 162                                                   rs5c->buf + 1) != size) {
 163                         dev_warn(&client->dev, "can't read registers\n");
 164                         return -EIO;
 165                 }
 166         } else {
 167                 if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
 168                         dev_warn(&client->dev, "can't read registers\n");
 169                         return -EIO;
 170                 }
 171         }
 172
 173         dev_dbg(&client->dev,
 174                 "%3ph (%02x) %3ph (%02x), %3ph, %3ph; %02x %02x\n",
 175                 rs5c->regs + 0, rs5c->regs[3],
 176                 rs5c->regs + 4, rs5c->regs[7],
 177                 rs5c->regs + 8, rs5c->regs + 11,
 178                 rs5c->regs[14], rs5c->regs[15]);
 179
 180         return 0;
 181 }
 182
 183 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
 184 {
 185         unsigned        hour;
 186
 187         if (rs5c->time24)
 188                 return bcd2bin(reg & 0x3f);
 189
 190         hour = bcd2bin(reg & 0x1f);
 191         if (hour == 12)
 192                 hour = 0;
 193         if (reg & 0x20)
 194                 hour += 12;
 195         return hour;
 196 }
 197
 198 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
 199 {
 200         if (rs5c->time24)
 201                 return bin2bcd(hour);
 202
 203         if (hour > 12)
 204                 return 0x20 | bin2bcd(hour - 12);
 205         if (hour == 12)
 206                 return 0x20 | bin2bcd(12);
 207         if (hour == 0)
 208                 return bin2bcd(12);
 209         return bin2bcd(hour);
 210 }
 211
 212 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
 213 {
 214         struct i2c_client *client = to_i2c_client(dev);
 215         struct rs5c372  *rs5c = i2c_get_clientdata(client);
 216         int             status = rs5c_get_regs(rs5c);
 217         unsigned char ctrl2 = rs5c->regs[RS5C_REG_CTRL2];
 218
 219         if (status < 0)
 220                 return status;
 221
 222         switch (rs5c->type) {
 223         case rtc_r2025sd:
 224         case rtc_r2221tl:
 225                 if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
 226                     (rs5c->type == rtc_r2221tl &&  (ctrl2 & R2x2x_CTRL2_XSTP))) {
 227                         dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
 228                         return -EINVAL;
 229                 }
 230                 break;
 231         default:
 232                 if (ctrl2 & RS5C_CTRL2_XSTP) {
 233                         dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
 234                         return -EINVAL;
 235                 }
 236         }
 237
 238         tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
 239         tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
 240         tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
 241
 242         tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
 243         tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
 244
 245         /* tm->tm_mon is zero-based */
 246         tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
 247
 248         /* year is 1900 + tm->tm_year */
 249         tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
 250
 251         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 252                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 253                 __func__,
 254                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 255                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 256
 257         return 0;
 258 }
 259
 260 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
 261 {
 262         struct i2c_client *client = to_i2c_client(dev);
 263         struct rs5c372  *rs5c = i2c_get_clientdata(client);
 264         unsigned char   buf[7];
 265         unsigned char   ctrl2;
 266         int             addr;
 267
 268         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
 269                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 270                 __func__,
 271                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 272                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 273
 274         addr   = RS5C_ADDR(RS5C372_REG_SECS);
 275         buf[0] = bin2bcd(tm->tm_sec);
 276         buf[1] = bin2bcd(tm->tm_min);
 277         buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
 278         buf[3] = bin2bcd(tm->tm_wday);
 279         buf[4] = bin2bcd(tm->tm_mday);
 280         buf[5] = bin2bcd(tm->tm_mon + 1);
 281         buf[6] = bin2bcd(tm->tm_year - 100);
 282
 283         if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
 284                 dev_dbg(&client->dev, "%s: write error in line %i\n",
 285                         __func__, __LINE__);
 286                 return -EIO;
 287         }
 288
 289         addr = RS5C_ADDR(RS5C_REG_CTRL2);
 290         ctrl2 = i2c_smbus_read_byte_data(client, addr);
 291
 292         /* clear rtc warning bits */
 293         switch (rs5c->type) {
 294         case rtc_r2025sd:
 295         case rtc_r2221tl:
 296                 ctrl2 &= ~(R2x2x_CTRL2_VDET | R2x2x_CTRL2_PON);
 297                 if (rs5c->type == rtc_r2025sd)
 298                         ctrl2 |= R2x2x_CTRL2_XSTP;
 299                 else
 300                         ctrl2 &= ~R2x2x_CTRL2_XSTP;
 301                 break;
 302         default:
 303                 ctrl2 &= ~RS5C_CTRL2_XSTP;
 304                 break;
 305         }
 306
 307         if (i2c_smbus_write_byte_data(client, addr, ctrl2) < 0) {
 308                 dev_dbg(&client->dev, "%s: write error in line %i\n",
 309                         __func__, __LINE__);
 310                 return -EIO;
 311         }
 312
 313         return 0;
 314 }
 315
 316 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 317 #define NEED_TRIM
 318 #endif
 319
 320 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
 321 #define NEED_TRIM
 322 #endif
 323
 324 #ifdef  NEED_TRIM
 325 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
 326 {
 327         struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
 328         u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
 329
 330         if (osc)
 331                 *osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
 332
 333         if (trim) {
 334                 dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
 335                 tmp &= RS5C372_TRIM_MASK;
 336                 if (tmp & 0x3e) {
 337                         int t = tmp & 0x3f;
 338
 339                         if (tmp & 0x40)
 340                                 t = (~t | (s8)0xc0) + 1;
 341                         else
 342                                 t = t - 1;
 343
 344                         tmp = t * 2;
 345                 } else
 346                         tmp = 0;
 347                 *trim = tmp;
 348         }
 349
 350         return 0;
 351 }
 352 #endif
 353
 354 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 355 {
 356         struct i2c_client       *client = to_i2c_client(dev);
 357         struct rs5c372          *rs5c = i2c_get_clientdata(client);
 358         unsigned char           buf;
 359         int                     status, addr;
 360
 361         buf = rs5c->regs[RS5C_REG_CTRL1];
 362
 363         if (!rs5c->has_irq)
 364                 return -EINVAL;
 365
 366         status = rs5c_get_regs(rs5c);
 367         if (status < 0)
 368                 return status;
 369
 370         addr = RS5C_ADDR(RS5C_REG_CTRL1);
 371         if (enabled)
 372                 buf |= RS5C_CTRL1_AALE;
 373         else
 374                 buf &= ~RS5C_CTRL1_AALE;
 375
 376         if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
 377                 dev_warn(dev, "can't update alarm\n");
 378                 status = -EIO;
 379         } else
 380                 rs5c->regs[RS5C_REG_CTRL1] = buf;
 381
 382         return status;
 383 }
 384
 385
 386 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
 387  * which only exposes a polled programming interface; and since
 388  * these calls map directly to those EFI requests; we don't demand
 389  * we have an IRQ for this chip when we go through this API.
 390  *
 391  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
 392  * though, managed through RTC_AIE_{ON,OFF} requests.
 393  */
 394
 395 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 396 {
 397         struct i2c_client       *client = to_i2c_client(dev);
 398         struct rs5c372          *rs5c = i2c_get_clientdata(client);
 399         int                     status;
 400
 401         status = rs5c_get_regs(rs5c);
 402         if (status < 0)
 403                 return status;
 404
 405         /* report alarm time */
 406         t->time.tm_sec = 0;
 407         t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
 408         t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
 409
 410         /* ... and status */
 411         t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
 412         t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
 413
 414         return 0;
 415 }
 416
 417 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 418 {
 419         struct i2c_client       *client = to_i2c_client(dev);
 420         struct rs5c372          *rs5c = i2c_get_clientdata(client);
 421         int                     status, addr, i;
 422         unsigned char           buf[3];
 423
 424         /* only handle up to 24 hours in the future, like RTC_ALM_SET */
 425         if (t->time.tm_mday != -1
 426                         || t->time.tm_mon != -1
 427                         || t->time.tm_year != -1)
 428                 return -EINVAL;
 429
 430         /* REVISIT: round up tm_sec */
 431
 432         /* if needed, disable irq (clears pending status) */
 433         status = rs5c_get_regs(rs5c);
 434         if (status < 0)
 435                 return status;
 436         if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
 437                 addr = RS5C_ADDR(RS5C_REG_CTRL1);
 438                 buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
 439                 if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
 440                         dev_dbg(dev, "can't disable alarm\n");
 441                         return -EIO;
 442                 }
 443                 rs5c->regs[RS5C_REG_CTRL1] = buf[0];
 444         }
 445
 446         /* set alarm */
 447         buf[0] = bin2bcd(t->time.tm_min);
 448         buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
 449         buf[2] = 0x7f;  /* any/all days */
 450
 451         for (i = 0; i < sizeof(buf); i++) {
 452                 addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
 453                 if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
 454                         dev_dbg(dev, "can't set alarm time\n");
 455                         return -EIO;
 456                 }
 457         }
 458
 459         /* ... and maybe enable its irq */
 460         if (t->enabled) {
 461                 addr = RS5C_ADDR(RS5C_REG_CTRL1);
 462                 buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
 463                 if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
 464                         dev_warn(dev, "can't enable alarm\n");
 465                 rs5c->regs[RS5C_REG_CTRL1] = buf[0];
 466         }
 467
 468         return 0;
 469 }
 470
 471 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 472
 473 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
 474 {
 475         int err, osc, trim;
 476
 477         err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
 478         if (err == 0) {
 479                 seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
 480                                 osc / 1000, osc % 1000);
 481                 seq_printf(seq, "trim\t\t: %d\n", trim);
 482         }
 483
 484         return 0;
 485 }
 486
 487 #else
 488 #define rs5c372_rtc_proc        NULL
 489 #endif
 490
 491 static const struct rtc_class_ops rs5c372_rtc_ops = {
 492         .proc           = rs5c372_rtc_proc,
 493         .read_time      = rs5c372_rtc_read_time,
 494         .set_time       = rs5c372_rtc_set_time,
 495         .read_alarm     = rs5c_read_alarm,
 496         .set_alarm      = rs5c_set_alarm,
 497         .alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
 498 };
 499
 500 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
 501
 502 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
 503                                 struct device_attribute *attr, char *buf)
 504 {
 505         int err, trim;
 506
 507         err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
 508         if (err)
 509                 return err;
 510
 511         return sprintf(buf, "%d\n", trim);
 512 }
 513 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
 514
 515 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
 516                                 struct device_attribute *attr, char *buf)
 517 {
 518         int err, osc;
 519
 520         err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
 521         if (err)
 522                 return err;
 523
 524         return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
 525 }
 526 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
 527
 528 static int rs5c_sysfs_register(struct device *dev)
 529 {
 530         int err;
 531
 532         err = device_create_file(dev, &dev_attr_trim);
 533         if (err)
 534                 return err;
 535         err = device_create_file(dev, &dev_attr_osc);
 536         if (err)
 537                 device_remove_file(dev, &dev_attr_trim);
 538
 539         return err;
 540 }
 541
 542 static void rs5c_sysfs_unregister(struct device *dev)
 543 {
 544         device_remove_file(dev, &dev_attr_trim);
 545         device_remove_file(dev, &dev_attr_osc);
 546 }
 547
 548 #else
 549 static int rs5c_sysfs_register(struct device *dev)
 550 {
 551         return 0;
 552 }
 553
 554 static void rs5c_sysfs_unregister(struct device *dev)
 555 {
 556         /* nothing */
 557 }
 558 #endif  /* SYSFS */
 559
 560 static struct i2c_driver rs5c372_driver;
 561
 562 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
 563 {
 564         unsigned char buf[2];
 565         int addr, i, ret = 0;
 566
 567         addr   = RS5C_ADDR(RS5C_REG_CTRL1);
 568         buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
 569         buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
 570
 571         switch (rs5c372->type) {
 572         case rtc_r2025sd:
 573                 if (buf[1] & R2x2x_CTRL2_XSTP)
 574                         return ret;
 575                 break;
 576         case rtc_r2221tl:
 577                 if (!(buf[1] & R2x2x_CTRL2_XSTP))
 578                         return ret;
 579                 break;
 580         default:
 581                 if (!(buf[1] & RS5C_CTRL2_XSTP))
 582                         return ret;
 583                 break;
 584         }
 585
 586         /* use 24hr mode */
 587         switch (rs5c372->type) {
 588         case rtc_rs5c372a:
 589         case rtc_rs5c372b:
 590                 buf[1] |= RS5C372_CTRL2_24;
 591                 rs5c372->time24 = 1;
 592                 break;
 593         case rtc_r2025sd:
 594         case rtc_r2221tl:
 595         case rtc_rv5c386:
 596         case rtc_rv5c387a:
 597                 buf[0] |= RV5C387_CTRL1_24;
 598                 rs5c372->time24 = 1;
 599                 break;
 600         default:
 601                 /* impossible */
 602                 break;
 603         }
 604
 605         for (i = 0; i < sizeof(buf); i++) {
 606                 addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
 607                 ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
 608                 if (unlikely(ret < 0))
 609                         return ret;
 610         }
 611
 612         rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
 613         rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
 614
 615         return 0;
 616 }
 617
 618 static int rs5c372_probe(struct i2c_client *client,
 619                          const struct i2c_device_id *id)
 620 {
 621         int err = 0;
 622         int smbus_mode = 0;
 623         struct rs5c372 *rs5c372;
 624
 625         dev_dbg(&client->dev, "%s\n", __func__);
 626
 627         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 628                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 629                 /*
 630                  * If we don't have any master mode adapter, try breaking
 631                  * it down in to the barest of capabilities.
 632                  */
 633                 if (i2c_check_functionality(client->adapter,
 634                                 I2C_FUNC_SMBUS_BYTE_DATA |
 635                                 I2C_FUNC_SMBUS_I2C_BLOCK))
 636                         smbus_mode = 1;
 637                 else {
 638                         /* Still no good, give up */
 639                         err = -ENODEV;
 640                         goto exit;
 641                 }
 642         }
 643
 644         rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
 645                                 GFP_KERNEL);
 646         if (!rs5c372) {
 647                 err = -ENOMEM;
 648                 goto exit;
 649         }
 650
 651         rs5c372->client = client;
 652         i2c_set_clientdata(client, rs5c372);
 653         if (client->dev.of_node)
 654                 rs5c372->type = (enum rtc_type)
 655                         of_device_get_match_data(&client->dev);
 656         else
 657                 rs5c372->type = id->driver_data;
 658
 659         /* we read registers 0x0f then 0x00-0x0f; skip the first one */
 660         rs5c372->regs = &rs5c372->buf[1];
 661         rs5c372->smbus = smbus_mode;
 662
 663         err = rs5c_get_regs(rs5c372);
 664         if (err < 0)
 665                 goto exit;
 666
 667         /* clock may be set for am/pm or 24 hr time */
 668         switch (rs5c372->type) {
 669         case rtc_rs5c372a:
 670         case rtc_rs5c372b:
 671                 /* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
 672                  * so does periodic irq, except some 327a modes.
 673                  */
 674                 if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
 675                         rs5c372->time24 = 1;
 676                 break;
 677         case rtc_r2025sd:
 678         case rtc_r2221tl:
 679         case rtc_rv5c386:
 680         case rtc_rv5c387a:
 681                 if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
 682                         rs5c372->time24 = 1;
 683                 /* alarm uses ALARM_W; and nINTRB for alarm and periodic
 684                  * irq, on both 386 and 387
 685                  */
 686                 break;
 687         default:
 688                 dev_err(&client->dev, "unknown RTC type\n");
 689                 goto exit;
 690         }
 691
 692         /* if the oscillator lost power and no other software (like
 693          * the bootloader) set it up, do it here.
 694          *
 695          * The R2025S/D does this a little differently than the other
 696          * parts, so we special case that..
 697          */
 698         err = rs5c_oscillator_setup(rs5c372);
 699         if (unlikely(err < 0)) {
 700                 dev_err(&client->dev, "setup error\n");
 701                 goto exit;
 702         }
 703
 704         dev_info(&client->dev, "%s found, %s\n",
 705                         ({ char *s; switch (rs5c372->type) {
 706                         case rtc_r2025sd:       s = "r2025sd"; break;
 707                         case rtc_r2221tl:       s = "r2221tl"; break;
 708                         case rtc_rs5c372a:      s = "rs5c372a"; break;
 709                         case rtc_rs5c372b:      s = "rs5c372b"; break;
 710                         case rtc_rv5c386:       s = "rv5c386"; break;
 711                         case rtc_rv5c387a:      s = "rv5c387a"; break;
 712                         default:                s = "chip"; break;
 713                         }; s;}),
 714                         rs5c372->time24 ? "24hr" : "am/pm"
 715                         );
 716
 717         /* REVISIT use client->irq to register alarm irq ... */
 718         rs5c372->rtc = devm_rtc_device_register(&client->dev,
 719                                         rs5c372_driver.driver.name,
 720                                         &rs5c372_rtc_ops, THIS_MODULE);
 721
 722         if (IS_ERR(rs5c372->rtc)) {
 723                 err = PTR_ERR(rs5c372->rtc);
 724                 goto exit;
 725         }
 726
 727         err = rs5c_sysfs_register(&client->dev);
 728         if (err)
 729                 goto exit;
 730
 731         return 0;
 732
 733 exit:
 734         return err;
 735 }
 736
 737 static int rs5c372_remove(struct i2c_client *client)
 738 {
 739         rs5c_sysfs_unregister(&client->dev);
 740         return 0;
 741 }
 742
 743 static struct i2c_driver rs5c372_driver = {
 744         .driver         = {
 745                 .name   = "rtc-rs5c372",
 746                 .of_match_table = of_match_ptr(rs5c372_of_match),
 747         },
 748         .probe          = rs5c372_probe,
 749         .remove         = rs5c372_remove,
 750         .id_table       = rs5c372_id,
 751 };
 752
 753 module_i2c_driver(rs5c372_driver);
 754
 755 MODULE_AUTHOR(
 756                 "Pavel Mironchik <pmironchik@optifacio.net>, "
 757                 "Alessandro Zummo <a.zummo@towertech.it>, "
 758                 "Paul Mundt <lethal@linux-sh.org>");
 759 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
 760 MODULE_LICENSE("GPL");