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 int rx8025_check_validity(struct device *dev)
 108 {
 109         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 110         int ctrl2;
 111
 112         ctrl2 = rx8025_read_reg(rx8025->client, RX8025_REG_CTRL2);
 113         if (ctrl2 < 0)
 114                 return ctrl2;
 115
 116         if (ctrl2 & RX8025_BIT_CTRL2_VDET)
 117                 dev_warn(dev, "power voltage drop detected\n");
 118
 119         if (ctrl2 & RX8025_BIT_CTRL2_PON) {
 120                 dev_warn(dev, "power-on reset detected, date is invalid\n");
 121                 return -EINVAL;
 122         }
 123
 124         if (!(ctrl2 & RX8025_BIT_CTRL2_XST)) {
 125                 dev_warn(dev, "crystal stopped, date is invalid\n");
 126                 return -EINVAL;
 127         }
 128
 129         return 0;
 130 }
 131
 132 static int rx8025_reset_validity(struct i2c_client *client)
 133 {
 134         int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 135
 136         if (ctrl2 < 0)
 137                 return ctrl2;
 138
 139         ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
 140
 141         return rx8025_write_reg(client, RX8025_REG_CTRL2,
 142                                 ctrl2 | RX8025_BIT_CTRL2_XST);
 143 }
 144
 145 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
 146 {
 147         struct i2c_client *client = dev_id;
 148         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 149         int status;
 150
 151         status = rx8025_read_reg(client, RX8025_REG_CTRL2);
 152         if (status < 0)
 153                 goto out;
 154
 155         if (!(status & RX8025_BIT_CTRL2_XST))
 156                 dev_warn(&client->dev, "Oscillation stop was detected,"
 157                          "you may have to readjust the clock\n");
 158
 159         if (status & RX8025_BIT_CTRL2_CTFG) {
 160                 /* periodic */
 161                 status &= ~RX8025_BIT_CTRL2_CTFG;
 162                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
 163         }
 164
 165         if (status & RX8025_BIT_CTRL2_DAFG) {
 166                 /* alarm */
 167                 status &= RX8025_BIT_CTRL2_DAFG;
 168                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
 169                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
 170                         goto out;
 171                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
 172         }
 173
 174 out:
 175         return IRQ_HANDLED;
 176 }
 177
 178 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
 179 {
 180         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 181         u8 date[7];
 182         int err;
 183
 184         err = rx8025_check_validity(dev);
 185         if (err)
 186                 return err;
 187
 188         err = rx8025_read_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 189         if (err)
 190                 return err;
 191
 192         dev_dbg(dev, "%s: read 0x%02x 0x%02x "
 193                 "0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n", __func__,
 194                 date[0], date[1], date[2], date[3], date[4],
 195                 date[5], date[6]);
 196
 197         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
 198         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
 199         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 200                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
 201         else
 202                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
 203                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
 204
 205         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
 206         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
 207         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
 208
 209         dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
 210                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 211                 dt->tm_mday, dt->tm_mon, dt->tm_year);
 212
 213         return rtc_valid_tm(dt);
 214 }
 215
 216 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
 217 {
 218         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 219         u8 date[7];
 220         int ret;
 221
 222         if ((dt->tm_year < 100) || (dt->tm_year > 199))
 223                 return -EINVAL;
 224
 225         /*
 226          * Here the read-only bits are written as "0".  I'm not sure if that
 227          * is sound.
 228          */
 229         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
 230         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
 231         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 232                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
 233         else
 234                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
 235                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
 236
 237         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
 238         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
 239         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
 240         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
 241
 242         dev_dbg(dev,
 243                 "%s: write 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n",
 244                 __func__,
 245                 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
 246
 247         ret = rx8025_write_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 248         if (ret < 0)
 249                 return ret;
 250
 251         return rx8025_reset_validity(rx8025->client);
 252 }
 253
 254 static int rx8025_init_client(struct i2c_client *client)
 255 {
 256         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 257         u8 ctrl[2], ctrl2;
 258         int need_clear = 0;
 259         int err;
 260
 261         err = rx8025_read_regs(rx8025->client, RX8025_REG_CTRL1, 2, ctrl);
 262         if (err)
 263                 goto out;
 264
 265         /* Keep test bit zero ! */
 266         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
 267
 268         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
 269                 dev_warn(&client->dev, "Alarm was detected\n");
 270                 need_clear = 1;
 271         }
 272
 273         if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
 274                 need_clear = 1;
 275
 276         if (need_clear) {
 277                 ctrl2 = ctrl[1];
 278                 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
 279                            RX8025_BIT_CTRL2_DAFG);
 280
 281                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
 282         }
 283 out:
 284         return err;
 285 }
 286
 287 /* Alarm support */
 288 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 289 {
 290         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 291         struct i2c_client *client = rx8025->client;
 292         u8 ald[2];
 293         int ctrl2, err;
 294
 295         if (client->irq <= 0)
 296                 return -EINVAL;
 297
 298         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
 299         if (err)
 300                 return err;
 301
 302         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 303         if (ctrl2 < 0)
 304                 return ctrl2;
 305
 306         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
 307                 __func__, ald[0], ald[1], ctrl2);
 308
 309         /* Hardware alarms precision is 1 minute! */
 310         t->time.tm_sec = 0;
 311         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 312         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 313                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
 314         else
 315                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
 316                         + (ald[1] & 0x20 ? 12 : 0);
 317
 318         t->time.tm_wday = -1;
 319         t->time.tm_mday = -1;
 320         t->time.tm_mon = -1;
 321         t->time.tm_year = -1;
 322
 323         dev_dbg(dev, "%s: date: %ds %dm %dh %dmd %dm %dy\n",
 324                 __func__,
 325                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 326                 t->time.tm_mday, t->time.tm_mon, t->time.tm_year);
 327         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
 328         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
 329
 330         return err;
 331 }
 332
 333 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 334 {
 335         struct i2c_client *client = to_i2c_client(dev);
 336         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 337         u8 ald[2];
 338         int err;
 339
 340         if (client->irq <= 0)
 341                 return -EINVAL;
 342
 343         /* Hardware alarm precision is 1 minute! */
 344         ald[0] = bin2bcd(t->time.tm_min);
 345         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 346                 ald[1] = bin2bcd(t->time.tm_hour);
 347         else
 348                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
 349                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
 350
 351         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
 352
 353         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
 354                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 355                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 356                                        rx8025->ctrl1);
 357                 if (err)
 358                         return err;
 359         }
 360         err = rx8025_write_regs(rx8025->client, RX8025_REG_ALDMIN, 2, ald);
 361         if (err)
 362                 return err;
 363
 364         if (t->enabled) {
 365                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
 366                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 367                                        rx8025->ctrl1);
 368                 if (err)
 369                         return err;
 370         }
 371
 372         return 0;
 373 }
 374
 375 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
 376 {
 377         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 378         u8 ctrl1;
 379         int err;
 380
 381         ctrl1 = rx8025->ctrl1;
 382         if (enabled)
 383                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
 384         else
 385                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 386
 387         if (ctrl1 != rx8025->ctrl1) {
 388                 rx8025->ctrl1 = ctrl1;
 389                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 390                                        rx8025->ctrl1);
 391                 if (err)
 392                         return err;
 393         }
 394         return 0;
 395 }
 396
 397 static struct rtc_class_ops rx8025_rtc_ops = {
 398         .read_time = rx8025_get_time,
 399         .set_time = rx8025_set_time,
 400         .read_alarm = rx8025_read_alarm,
 401         .set_alarm = rx8025_set_alarm,
 402         .alarm_irq_enable = rx8025_alarm_irq_enable,
 403 };
 404
 405 /*
 406  * Clock precision adjustment support
 407  *
 408  * According to the RX8025 SA/NB application manual the frequency and
 409  * temperature characteristics can be approximated using the following
 410  * equation:
 411  *
 412  *   df = a * (ut - t)**2
 413  *
 414  *   df: Frequency deviation in any temperature
 415  *   a : Coefficient = (-35 +-5) * 10**-9
 416  *   ut: Ultimate temperature in degree = +25 +-5 degree
 417  *   t : Any temperature in degree
 418  *
 419  * Note that the clock adjustment in ppb must be entered (which is
 420  * the negative value of the deviation).
 421  */
 422 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
 423 {
 424         struct i2c_client *client = to_i2c_client(dev);
 425         int digoff;
 426
 427         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
 428         if (digoff < 0)
 429                 return digoff;
 430
 431         *adj = digoff >= 64 ? digoff - 128 : digoff;
 432         if (*adj > 0)
 433                 (*adj)--;
 434         *adj *= -RX8025_ADJ_RESOLUTION;
 435
 436         return 0;
 437 }
 438
 439 static int rx8025_set_clock_adjust(struct device *dev, int adj)
 440 {
 441         struct i2c_client *client = to_i2c_client(dev);
 442         u8 digoff;
 443         int err;
 444
 445         adj /= -RX8025_ADJ_RESOLUTION;
 446         if (adj > RX8025_ADJ_DATA_MAX)
 447                 adj = RX8025_ADJ_DATA_MAX;
 448         else if (adj < RX8025_ADJ_DATA_MIN)
 449                 adj = RX8025_ADJ_DATA_MIN;
 450         else if (adj > 0)
 451                 adj++;
 452         else if (adj < 0)
 453                 adj += 128;
 454         digoff = adj;
 455
 456         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
 457         if (err)
 458                 return err;
 459
 460         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
 461
 462         return 0;
 463 }
 464
 465 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
 466                                               struct device_attribute *attr,
 467                                               char *buf)
 468 {
 469         int err, adj;
 470
 471         err = rx8025_get_clock_adjust(dev, &adj);
 472         if (err)
 473                 return err;
 474
 475         return sprintf(buf, "%d\n", adj);
 476 }
 477
 478 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
 479                                                struct device_attribute *attr,
 480                                                const char *buf, size_t count)
 481 {
 482         int adj, err;
 483
 484         if (sscanf(buf, "%i", &adj) != 1)
 485                 return -EINVAL;
 486
 487         err = rx8025_set_clock_adjust(dev, adj);
 488
 489         return err ? err : count;
 490 }
 491
 492 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
 493                    rx8025_sysfs_show_clock_adjust,
 494                    rx8025_sysfs_store_clock_adjust);
 495
 496 static int rx8025_sysfs_register(struct device *dev)
 497 {
 498         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
 499 }
 500
 501 static void rx8025_sysfs_unregister(struct device *dev)
 502 {
 503         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
 504 }
 505
 506 static int rx8025_probe(struct i2c_client *client,
 507                         const struct i2c_device_id *id)
 508 {
 509         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 510         struct rx8025_data *rx8025;
 511         int err = 0;
 512
 513         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 514                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 515                 dev_err(&adapter->dev,
 516                         "doesn't support required functionality\n");
 517                 return -EIO;
 518         }
 519
 520         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 521         if (!rx8025) {
 522                 return -ENOMEM;
 523         }
 524
 525         rx8025->client = client;
 526         i2c_set_clientdata(client, rx8025);
 527
 528         err = rx8025_init_client(client);
 529         if (err)
 530                 return err;
 531
 532         rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
 533                                           &rx8025_rtc_ops, THIS_MODULE);
 534         if (IS_ERR(rx8025->rtc)) {
 535                 dev_err(&client->dev, "unable to register the class device\n");
 536                 return PTR_ERR(rx8025->rtc);
 537         }
 538
 539         if (client->irq > 0) {
 540                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 541                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 542                                                 rx8025_handle_irq, 0, "rx8025",
 543                                                 client);
 544                 if (err) {
 545                         dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
 546                         client->irq = 0;
 547                 }
 548         }
 549
 550         rx8025->rtc->max_user_freq = 1;
 551
 552         err = rx8025_sysfs_register(&client->dev);
 553         return err;
 554 }
 555
 556 static int rx8025_remove(struct i2c_client *client)
 557 {
 558         rx8025_sysfs_unregister(&client->dev);
 559         return 0;
 560 }
 561
 562 static struct i2c_driver rx8025_driver = {
 563         .driver = {
 564                 .name = "rtc-rx8025",
 565         },
 566         .probe          = rx8025_probe,
 567         .remove         = rx8025_remove,
 568         .id_table       = rx8025_id,
 569 };
 570
 571 module_i2c_driver(rx8025_driver);
 572
 573 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 574 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
 575 MODULE_LICENSE("GPL");