drivers/rtc/rtc-rx8025.c

   1 /*
   2  * Driver for Epson's RTC module RX-8025 SA/NB
   3  *
   4  * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
   5  *
   6  * Copyright (C) 2005 by Digi International Inc.
   7  * All rights reserved.
   8  *
   9  * Modified by fengjh at rising.com.cn
  10  * <http://lists.lm-sensors.org/mailman/listinfo/lm-sensors>
  11  * 2006.11
  12  *
  13  * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
  14  * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
  15  * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
  16  *
  17  * This program is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU General Public License
  19  * version 2 as published by the Free Software Foundation.
  20  */
  21 #include <linux/bcd.h>
  22 #include <linux/bitops.h>
  23 #include <linux/i2c.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/rtc.h>
  27
  28 /* Register definitions */
  29 #define RX8025_REG_SEC          0x00
  30 #define RX8025_REG_MIN          0x01
  31 #define RX8025_REG_HOUR         0x02
  32 #define RX8025_REG_WDAY         0x03
  33 #define RX8025_REG_MDAY         0x04
  34 #define RX8025_REG_MONTH        0x05
  35 #define RX8025_REG_YEAR         0x06
  36 #define RX8025_REG_DIGOFF       0x07
  37 #define RX8025_REG_ALWMIN       0x08
  38 #define RX8025_REG_ALWHOUR      0x09
  39 #define RX8025_REG_ALWWDAY      0x0a
  40 #define RX8025_REG_ALDMIN       0x0b
  41 #define RX8025_REG_ALDHOUR      0x0c
  42 /* 0x0d is reserved */
  43 #define RX8025_REG_CTRL1        0x0e
  44 #define RX8025_REG_CTRL2        0x0f
  45
  46 #define RX8025_BIT_CTRL1_CT     (7 << 0)
  47 /* 1 Hz periodic level irq */
  48 #define RX8025_BIT_CTRL1_CT_1HZ 4
  49 #define RX8025_BIT_CTRL1_TEST   BIT(3)
  50 #define RX8025_BIT_CTRL1_1224   BIT(5)
  51 #define RX8025_BIT_CTRL1_DALE   BIT(6)
  52 #define RX8025_BIT_CTRL1_WALE   BIT(7)
  53
  54 #define RX8025_BIT_CTRL2_DAFG   BIT(0)
  55 #define RX8025_BIT_CTRL2_WAFG   BIT(1)
  56 #define RX8025_BIT_CTRL2_CTFG   BIT(2)
  57 #define RX8025_BIT_CTRL2_PON    BIT(4)
  58 #define RX8025_BIT_CTRL2_XST    BIT(5)
  59 #define RX8025_BIT_CTRL2_VDET   BIT(6)
  60
  61 /* Clock precision adjustment */
  62 #define RX8025_ADJ_RESOLUTION   3050 /* in ppb */
  63 #define RX8025_ADJ_DATA_MAX     62
  64 #define RX8025_ADJ_DATA_MIN     -62
  65
  66 static const struct i2c_device_id rx8025_id[] = {
  67         { "rx8025", 0 },
  68         { }
  69 };
  70 MODULE_DEVICE_TABLE(i2c, rx8025_id);
  71
  72 struct rx8025_data {
  73         struct i2c_client *client;
  74         struct rtc_device *rtc;
  75         u8 ctrl1;
  76 };
  77
  78 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
  79 {
  80         return i2c_smbus_read_byte_data(client, number << 4);
  81 }
  82
  83 static int rx8025_read_regs(const struct i2c_client *client,
  84                             u8 number, u8 length, u8 *values)
  85 {
  86         int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
  87                                                 values);
  88         if (ret != length)
  89                 return ret < 0 ? ret : -EIO;
  90
  91         return 0;
  92 }
  93
  94 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
  95                             u8 value)
  96 {
  97         return i2c_smbus_write_byte_data(client, number << 4, value);
  98 }
  99
 100 static s32 rx8025_write_regs(const struct i2c_client *client,
 101                              u8 number, u8 length, const u8 *values)
 102 {
 103         return i2c_smbus_write_i2c_block_data(client, number << 4,
 104                                               length, values);
 105 }
 106
 107 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
 108 {
 109         struct i2c_client *client = dev_id;
 110         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 111         int status;
 112
 113         status = rx8025_read_reg(client, RX8025_REG_CTRL2);
 114         if (status < 0)
 115                 goto out;
 116
 117         if (!(status & RX8025_BIT_CTRL2_XST))
 118                 dev_warn(&client->dev, "Oscillation stop was detected,"
 119                          "you may have to readjust the clock\n");
 120
 121         if (status & RX8025_BIT_CTRL2_CTFG) {
 122                 /* periodic */
 123                 status &= ~RX8025_BIT_CTRL2_CTFG;
 124                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
 125         }
 126
 127         if (status & RX8025_BIT_CTRL2_DAFG) {
 128                 /* alarm */
 129                 status &= RX8025_BIT_CTRL2_DAFG;
 130                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
 131                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
 132                         goto out;
 133                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
 134         }
 135
 136         /* acknowledge IRQ */
 137         rx8025_write_reg(client, RX8025_REG_CTRL2,
 138                          status | RX8025_BIT_CTRL2_XST);
 139
 140 out:
 141         return IRQ_HANDLED;
 142 }
 143
 144 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
 145 {
 146         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 147         u8 date[7];
 148         int ctrl, err;
 149
 150         ctrl = rx8025_read_reg(rx8025->client, RX8025_REG_CTRL2);
 151         if (ctrl < 0)
 152                 return ctrl;
 153
 154         if (ctrl & RX8025_BIT_CTRL2_PON) {
 155                 dev_warn(dev, "power-on reset detected, date is invalid\n");
 156                 return -EINVAL;
 157         }
 158
 159         if (!(ctrl & RX8025_BIT_CTRL2_XST)) {
 160                 dev_warn(dev, "crystal stopped, date is invalid\n");
 161                 return -EINVAL;
 162         }
 163
 164         err = rx8025_read_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 165         if (err)
 166                 return err;
 167
 168         dev_dbg(dev, "%s: read 0x%02x 0x%02x "
 169                 "0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n", __func__,
 170                 date[0], date[1], date[2], date[3], date[4],
 171                 date[5], date[6]);
 172
 173         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
 174         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
 175         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 176                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
 177         else
 178                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
 179                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
 180
 181         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
 182         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
 183         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
 184
 185         dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
 186                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 187                 dt->tm_mday, dt->tm_mon, dt->tm_year);
 188
 189         return rtc_valid_tm(dt);
 190 }
 191
 192 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
 193 {
 194         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 195         u8 date[7];
 196
 197         if ((dt->tm_year < 100) || (dt->tm_year > 199))
 198                 return -EINVAL;
 199
 200         /*
 201          * Here the read-only bits are written as "0".  I'm not sure if that
 202          * is sound.
 203          */
 204         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
 205         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
 206         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 207                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
 208         else
 209                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
 210                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
 211
 212         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
 213         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
 214         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
 215         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
 216
 217         dev_dbg(dev,
 218                 "%s: write 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n",
 219                 __func__,
 220                 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
 221
 222         return rx8025_write_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 223 }
 224
 225 static int rx8025_init_client(struct i2c_client *client)
 226 {
 227         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 228         u8 ctrl[2], ctrl2;
 229         int need_clear = 0;
 230         int err;
 231
 232         err = rx8025_read_regs(rx8025->client, RX8025_REG_CTRL1, 2, ctrl);
 233         if (err)
 234                 goto out;
 235
 236         /* Keep test bit zero ! */
 237         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
 238
 239         if (ctrl[1] & RX8025_BIT_CTRL2_PON) {
 240                 dev_warn(&client->dev, "power-on reset was detected, "
 241                          "you may have to readjust the clock\n");
 242                 need_clear = 1;
 243         }
 244
 245         if (ctrl[1] & RX8025_BIT_CTRL2_VDET) {
 246                 dev_warn(&client->dev, "a power voltage drop was detected, "
 247                          "you may have to readjust the clock\n");
 248                 need_clear = 1;
 249         }
 250
 251         if (!(ctrl[1] & RX8025_BIT_CTRL2_XST)) {
 252                 dev_warn(&client->dev, "Oscillation stop was detected,"
 253                          "you may have to readjust the clock\n");
 254                 need_clear = 1;
 255         }
 256
 257         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
 258                 dev_warn(&client->dev, "Alarm was detected\n");
 259                 need_clear = 1;
 260         }
 261
 262         if (!(ctrl[1] & RX8025_BIT_CTRL2_CTFG))
 263                 need_clear = 1;
 264
 265         if (need_clear) {
 266                 ctrl2 = ctrl[1];
 267                 ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET |
 268                            RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
 269                            RX8025_BIT_CTRL2_DAFG);
 270                 ctrl2 |= RX8025_BIT_CTRL2_XST;
 271
 272                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
 273         }
 274 out:
 275         return err;
 276 }
 277
 278 /* Alarm support */
 279 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 280 {
 281         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 282         struct i2c_client *client = rx8025->client;
 283         u8 ald[2];
 284         int ctrl2, err;
 285
 286         if (client->irq <= 0)
 287                 return -EINVAL;
 288
 289         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
 290         if (err)
 291                 return err;
 292
 293         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 294         if (ctrl2 < 0)
 295                 return ctrl2;
 296
 297         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
 298                 __func__, ald[0], ald[1], ctrl2);
 299
 300         /* Hardware alarms precision is 1 minute! */
 301         t->time.tm_sec = 0;
 302         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 303         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 304                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
 305         else
 306                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
 307                         + (ald[1] & 0x20 ? 12 : 0);
 308
 309         t->time.tm_wday = -1;
 310         t->time.tm_mday = -1;
 311         t->time.tm_mon = -1;
 312         t->time.tm_year = -1;
 313
 314         dev_dbg(dev, "%s: date: %ds %dm %dh %dmd %dm %dy\n",
 315                 __func__,
 316                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 317                 t->time.tm_mday, t->time.tm_mon, t->time.tm_year);
 318         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
 319         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
 320
 321         return err;
 322 }
 323
 324 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 325 {
 326         struct i2c_client *client = to_i2c_client(dev);
 327         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 328         u8 ald[2];
 329         int err;
 330
 331         if (client->irq <= 0)
 332                 return -EINVAL;
 333
 334         /* Hardware alarm precision is 1 minute! */
 335         ald[0] = bin2bcd(t->time.tm_min);
 336         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 337                 ald[1] = bin2bcd(t->time.tm_hour);
 338         else
 339                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
 340                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
 341
 342         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
 343
 344         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
 345                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 346                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 347                                        rx8025->ctrl1);
 348                 if (err)
 349                         return err;
 350         }
 351         err = rx8025_write_regs(rx8025->client, RX8025_REG_ALDMIN, 2, ald);
 352         if (err)
 353                 return err;
 354
 355         if (t->enabled) {
 356                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
 357                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 358                                        rx8025->ctrl1);
 359                 if (err)
 360                         return err;
 361         }
 362
 363         return 0;
 364 }
 365
 366 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
 367 {
 368         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 369         u8 ctrl1;
 370         int err;
 371
 372         ctrl1 = rx8025->ctrl1;
 373         if (enabled)
 374                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
 375         else
 376                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 377
 378         if (ctrl1 != rx8025->ctrl1) {
 379                 rx8025->ctrl1 = ctrl1;
 380                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 381                                        rx8025->ctrl1);
 382                 if (err)
 383                         return err;
 384         }
 385         return 0;
 386 }
 387
 388 static struct rtc_class_ops rx8025_rtc_ops = {
 389         .read_time = rx8025_get_time,
 390         .set_time = rx8025_set_time,
 391         .read_alarm = rx8025_read_alarm,
 392         .set_alarm = rx8025_set_alarm,
 393         .alarm_irq_enable = rx8025_alarm_irq_enable,
 394 };
 395
 396 /*
 397  * Clock precision adjustment support
 398  *
 399  * According to the RX8025 SA/NB application manual the frequency and
 400  * temperature characteristics can be approximated using the following
 401  * equation:
 402  *
 403  *   df = a * (ut - t)**2
 404  *
 405  *   df: Frequency deviation in any temperature
 406  *   a : Coefficient = (-35 +-5) * 10**-9
 407  *   ut: Ultimate temperature in degree = +25 +-5 degree
 408  *   t : Any temperature in degree
 409  *
 410  * Note that the clock adjustment in ppb must be entered (which is
 411  * the negative value of the deviation).
 412  */
 413 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
 414 {
 415         struct i2c_client *client = to_i2c_client(dev);
 416         int digoff;
 417
 418         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
 419         if (digoff < 0)
 420                 return digoff;
 421
 422         *adj = digoff >= 64 ? digoff - 128 : digoff;
 423         if (*adj > 0)
 424                 (*adj)--;
 425         *adj *= -RX8025_ADJ_RESOLUTION;
 426
 427         return 0;
 428 }
 429
 430 static int rx8025_set_clock_adjust(struct device *dev, int adj)
 431 {
 432         struct i2c_client *client = to_i2c_client(dev);
 433         u8 digoff;
 434         int err;
 435
 436         adj /= -RX8025_ADJ_RESOLUTION;
 437         if (adj > RX8025_ADJ_DATA_MAX)
 438                 adj = RX8025_ADJ_DATA_MAX;
 439         else if (adj < RX8025_ADJ_DATA_MIN)
 440                 adj = RX8025_ADJ_DATA_MIN;
 441         else if (adj > 0)
 442                 adj++;
 443         else if (adj < 0)
 444                 adj += 128;
 445         digoff = adj;
 446
 447         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
 448         if (err)
 449                 return err;
 450
 451         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
 452
 453         return 0;
 454 }
 455
 456 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
 457                                               struct device_attribute *attr,
 458                                               char *buf)
 459 {
 460         int err, adj;
 461
 462         err = rx8025_get_clock_adjust(dev, &adj);
 463         if (err)
 464                 return err;
 465
 466         return sprintf(buf, "%d\n", adj);
 467 }
 468
 469 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
 470                                                struct device_attribute *attr,
 471                                                const char *buf, size_t count)
 472 {
 473         int adj, err;
 474
 475         if (sscanf(buf, "%i", &adj) != 1)
 476                 return -EINVAL;
 477
 478         err = rx8025_set_clock_adjust(dev, adj);
 479
 480         return err ? err : count;
 481 }
 482
 483 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
 484                    rx8025_sysfs_show_clock_adjust,
 485                    rx8025_sysfs_store_clock_adjust);
 486
 487 static int rx8025_sysfs_register(struct device *dev)
 488 {
 489         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
 490 }
 491
 492 static void rx8025_sysfs_unregister(struct device *dev)
 493 {
 494         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
 495 }
 496
 497 static int rx8025_probe(struct i2c_client *client,
 498                         const struct i2c_device_id *id)
 499 {
 500         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 501         struct rx8025_data *rx8025;
 502         int err = 0;
 503
 504         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 505                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 506                 dev_err(&adapter->dev,
 507                         "doesn't support required functionality\n");
 508                 return -EIO;
 509         }
 510
 511         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 512         if (!rx8025) {
 513                 return -ENOMEM;
 514         }
 515
 516         rx8025->client = client;
 517         i2c_set_clientdata(client, rx8025);
 518
 519         err = rx8025_init_client(client);
 520         if (err)
 521                 return err;
 522
 523         rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
 524                                           &rx8025_rtc_ops, THIS_MODULE);
 525         if (IS_ERR(rx8025->rtc)) {
 526                 dev_err(&client->dev, "unable to register the class device\n");
 527                 return PTR_ERR(rx8025->rtc);
 528         }
 529
 530         if (client->irq > 0) {
 531                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 532                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 533                                                 rx8025_handle_irq, 0, "rx8025",
 534                                                 client);
 535                 if (err) {
 536                         dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
 537                         client->irq = 0;
 538                 }
 539         }
 540
 541         rx8025->rtc->irq_freq = 1;
 542         rx8025->rtc->max_user_freq = 1;
 543
 544         err = rx8025_sysfs_register(&client->dev);
 545         return err;
 546 }
 547
 548 static int rx8025_remove(struct i2c_client *client)
 549 {
 550         rx8025_sysfs_unregister(&client->dev);
 551         return 0;
 552 }
 553
 554 static struct i2c_driver rx8025_driver = {
 555         .driver = {
 556                 .name = "rtc-rx8025",
 557         },
 558         .probe          = rx8025_probe,
 559         .remove         = rx8025_remove,
 560         .id_table       = rx8025_id,
 561 };
 562
 563 module_i2c_driver(rx8025_driver);
 564
 565 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 566 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
 567 MODULE_LICENSE("GPL");