drivers/rtc/rtc-rx8025.c

   1 /*
   2  * Driver for Epson's RTC module RX-8025 SA/NB
   3  *
   4  * Copyright (C) 2009 Wolfgang Grandegger <[email protected]>
   5  *
   6  * Copyright (C) 2005 by Digi International Inc.
   7  * All rights reserved.
   8  *
   9  * Modified by fengjh at rising.com.cn
  10  * <[email protected]>
  11  * 2006.11
  12  *
  13  * Code cleanup by Sergei Poselenov, <[email protected]>
  14  * Converted to new style by Wolfgang Grandegger <[email protected]>
  15  * Alarm and periodic interrupt added by Dmitry Rakhchev <[email protected]>
  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         struct mutex *lock = &rx8025->rtc->ops_lock;
 150         int status;
 151
 152         mutex_lock(lock);
 153         status = rx8025_read_reg(client, RX8025_REG_CTRL2);
 154         if (status < 0)
 155                 goto out;
 156
 157         if (!(status & RX8025_BIT_CTRL2_XST))
 158                 dev_warn(&client->dev, "Oscillation stop was detected,"
 159                          "you may have to readjust the clock\n");
 160
 161         if (status & RX8025_BIT_CTRL2_CTFG) {
 162                 /* periodic */
 163                 status &= ~RX8025_BIT_CTRL2_CTFG;
 164                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
 165         }
 166
 167         if (status & RX8025_BIT_CTRL2_DAFG) {
 168                 /* alarm */
 169                 status &= RX8025_BIT_CTRL2_DAFG;
 170                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
 171                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
 172                         goto out;
 173                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
 174         }
 175
 176 out:
 177         mutex_unlock(lock);
 178
 179         return IRQ_HANDLED;
 180 }
 181
 182 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
 183 {
 184         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 185         u8 date[7];
 186         int err;
 187
 188         err = rx8025_check_validity(dev);
 189         if (err)
 190                 return err;
 191
 192         err = rx8025_read_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 193         if (err)
 194                 return err;
 195
 196         dev_dbg(dev, "%s: read %7ph\n", __func__, date);
 197
 198         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
 199         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
 200         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 201                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
 202         else
 203                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
 204                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
 205
 206         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
 207         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
 208         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
 209
 210         dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
 211
 212         return 0;
 213 }
 214
 215 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
 216 {
 217         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 218         u8 date[7];
 219         int ret;
 220
 221         if ((dt->tm_year < 100) || (dt->tm_year > 199))
 222                 return -EINVAL;
 223
 224         /*
 225          * Here the read-only bits are written as "0".  I'm not sure if that
 226          * is sound.
 227          */
 228         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
 229         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
 230         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 231                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
 232         else
 233                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
 234                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
 235
 236         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
 237         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
 238         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
 239         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
 240
 241         dev_dbg(dev, "%s: write %7ph\n", __func__, date);
 242
 243         ret = rx8025_write_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 244         if (ret < 0)
 245                 return ret;
 246
 247         return rx8025_reset_validity(rx8025->client);
 248 }
 249
 250 static int rx8025_init_client(struct i2c_client *client)
 251 {
 252         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 253         u8 ctrl[2], ctrl2;
 254         int need_clear = 0;
 255         int err;
 256
 257         err = rx8025_read_regs(rx8025->client, RX8025_REG_CTRL1, 2, ctrl);
 258         if (err)
 259                 goto out;
 260
 261         /* Keep test bit zero ! */
 262         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
 263
 264         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
 265                 dev_warn(&client->dev, "Alarm was detected\n");
 266                 need_clear = 1;
 267         }
 268
 269         if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
 270                 need_clear = 1;
 271
 272         if (need_clear) {
 273                 ctrl2 = ctrl[1];
 274                 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
 275                            RX8025_BIT_CTRL2_DAFG);
 276
 277                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
 278         }
 279 out:
 280         return err;
 281 }
 282
 283 /* Alarm support */
 284 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 285 {
 286         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 287         struct i2c_client *client = rx8025->client;
 288         u8 ald[2];
 289         int ctrl2, err;
 290
 291         if (client->irq <= 0)
 292                 return -EINVAL;
 293
 294         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
 295         if (err)
 296                 return err;
 297
 298         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 299         if (ctrl2 < 0)
 300                 return ctrl2;
 301
 302         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
 303                 __func__, ald[0], ald[1], ctrl2);
 304
 305         /* Hardware alarms precision is 1 minute! */
 306         t->time.tm_sec = 0;
 307         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 308         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 309                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
 310         else
 311                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
 312                         + (ald[1] & 0x20 ? 12 : 0);
 313
 314         dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
 315         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
 316         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
 317
 318         return err;
 319 }
 320
 321 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 322 {
 323         struct i2c_client *client = to_i2c_client(dev);
 324         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 325         u8 ald[2];
 326         int err;
 327
 328         if (client->irq <= 0)
 329                 return -EINVAL;
 330
 331         /*
 332          * Hardware alarm precision is 1 minute!
 333          * round up to nearest minute
 334          */
 335         if (t->time.tm_sec) {
 336                 time64_t alarm_time = rtc_tm_to_time64(&t->time);
 337
 338                 alarm_time += 60 - t->time.tm_sec;
 339                 rtc_time64_to_tm(alarm_time, &t->time);
 340         }
 341
 342         ald[0] = bin2bcd(t->time.tm_min);
 343         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 344                 ald[1] = bin2bcd(t->time.tm_hour);
 345         else
 346                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
 347                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
 348
 349         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
 350
 351         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
 352                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 353                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 354                                        rx8025->ctrl1);
 355                 if (err)
 356                         return err;
 357         }
 358         err = rx8025_write_regs(rx8025->client, RX8025_REG_ALDMIN, 2, ald);
 359         if (err)
 360                 return err;
 361
 362         if (t->enabled) {
 363                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
 364                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 365                                        rx8025->ctrl1);
 366                 if (err)
 367                         return err;
 368         }
 369
 370         return 0;
 371 }
 372
 373 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
 374 {
 375         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 376         u8 ctrl1;
 377         int err;
 378
 379         ctrl1 = rx8025->ctrl1;
 380         if (enabled)
 381                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
 382         else
 383                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 384
 385         if (ctrl1 != rx8025->ctrl1) {
 386                 rx8025->ctrl1 = ctrl1;
 387                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 388                                        rx8025->ctrl1);
 389                 if (err)
 390                         return err;
 391         }
 392         return 0;
 393 }
 394
 395 static const struct rtc_class_ops rx8025_rtc_ops = {
 396         .read_time = rx8025_get_time,
 397         .set_time = rx8025_set_time,
 398         .read_alarm = rx8025_read_alarm,
 399         .set_alarm = rx8025_set_alarm,
 400         .alarm_irq_enable = rx8025_alarm_irq_enable,
 401 };
 402
 403 /*
 404  * Clock precision adjustment support
 405  *
 406  * According to the RX8025 SA/NB application manual the frequency and
 407  * temperature characteristics can be approximated using the following
 408  * equation:
 409  *
 410  *   df = a * (ut - t)**2
 411  *
 412  *   df: Frequency deviation in any temperature
 413  *   a : Coefficient = (-35 +-5) * 10**-9
 414  *   ut: Ultimate temperature in degree = +25 +-5 degree
 415  *   t : Any temperature in degree
 416  *
 417  * Note that the clock adjustment in ppb must be entered (which is
 418  * the negative value of the deviation).
 419  */
 420 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
 421 {
 422         struct i2c_client *client = to_i2c_client(dev);
 423         int digoff;
 424
 425         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
 426         if (digoff < 0)
 427                 return digoff;
 428
 429         *adj = digoff >= 64 ? digoff - 128 : digoff;
 430         if (*adj > 0)
 431                 (*adj)--;
 432         *adj *= -RX8025_ADJ_RESOLUTION;
 433
 434         return 0;
 435 }
 436
 437 static int rx8025_set_clock_adjust(struct device *dev, int adj)
 438 {
 439         struct i2c_client *client = to_i2c_client(dev);
 440         u8 digoff;
 441         int err;
 442
 443         adj /= -RX8025_ADJ_RESOLUTION;
 444         if (adj > RX8025_ADJ_DATA_MAX)
 445                 adj = RX8025_ADJ_DATA_MAX;
 446         else if (adj < RX8025_ADJ_DATA_MIN)
 447                 adj = RX8025_ADJ_DATA_MIN;
 448         else if (adj > 0)
 449                 adj++;
 450         else if (adj < 0)
 451                 adj += 128;
 452         digoff = adj;
 453
 454         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
 455         if (err)
 456                 return err;
 457
 458         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
 459
 460         return 0;
 461 }
 462
 463 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
 464                                               struct device_attribute *attr,
 465                                               char *buf)
 466 {
 467         int err, adj;
 468
 469         err = rx8025_get_clock_adjust(dev, &adj);
 470         if (err)
 471                 return err;
 472
 473         return sprintf(buf, "%d\n", adj);
 474 }
 475
 476 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
 477                                                struct device_attribute *attr,
 478                                                const char *buf, size_t count)
 479 {
 480         int adj, err;
 481
 482         if (sscanf(buf, "%i", &adj) != 1)
 483                 return -EINVAL;
 484
 485         err = rx8025_set_clock_adjust(dev, adj);
 486
 487         return err ? err : count;
 488 }
 489
 490 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
 491                    rx8025_sysfs_show_clock_adjust,
 492                    rx8025_sysfs_store_clock_adjust);
 493
 494 static int rx8025_sysfs_register(struct device *dev)
 495 {
 496         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
 497 }
 498
 499 static void rx8025_sysfs_unregister(struct device *dev)
 500 {
 501         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
 502 }
 503
 504 static int rx8025_probe(struct i2c_client *client,
 505                         const struct i2c_device_id *id)
 506 {
 507         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 508         struct rx8025_data *rx8025;
 509         int err = 0;
 510
 511         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 512                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 513                 dev_err(&adapter->dev,
 514                         "doesn't support required functionality\n");
 515                 return -EIO;
 516         }
 517
 518         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 519         if (!rx8025)
 520                 return -ENOMEM;
 521
 522         rx8025->client = client;
 523         i2c_set_clientdata(client, rx8025);
 524
 525         err = rx8025_init_client(client);
 526         if (err)
 527                 return err;
 528
 529         rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
 530                                           &rx8025_rtc_ops, THIS_MODULE);
 531         if (IS_ERR(rx8025->rtc)) {
 532                 dev_err(&client->dev, "unable to register the class device\n");
 533                 return PTR_ERR(rx8025->rtc);
 534         }
 535
 536         if (client->irq > 0) {
 537                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 538                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 539                                                 rx8025_handle_irq,
 540                                                 IRQF_ONESHOT,
 541                                                 "rx8025", client);
 542                 if (err) {
 543                         dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
 544                         client->irq = 0;
 545                 }
 546         }
 547
 548         rx8025->rtc->max_user_freq = 1;
 549
 550         /* the rx8025 alarm only supports a minute accuracy */
 551         rx8025->rtc->uie_unsupported = 1;
 552
 553         err = rx8025_sysfs_register(&client->dev);
 554         return err;
 555 }
 556
 557 static int rx8025_remove(struct i2c_client *client)
 558 {
 559         rx8025_sysfs_unregister(&client->dev);
 560         return 0;
 561 }
 562
 563 static struct i2c_driver rx8025_driver = {
 564         .driver = {
 565                 .name = "rtc-rx8025",
 566         },
 567         .probe          = rx8025_probe,
 568         .remove         = rx8025_remove,
 569         .id_table       = rx8025_id,
 570 };
 571
 572 module_i2c_driver(rx8025_driver);
 573
 574 MODULE_AUTHOR("Wolfgang Grandegger <[email protected]>");
 575 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
 576 MODULE_LICENSE("GPL");