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 0x%02x 0x%02x "
 197                 "0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n", __func__,
 198                 date[0], date[1], date[2], date[3], date[4],
 199                 date[5], date[6]);
 200
 201         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
 202         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
 203         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 204                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
 205         else
 206                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
 207                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
 208
 209         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
 210         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
 211         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
 212
 213         dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
 214                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 215                 dt->tm_mday, dt->tm_mon, dt->tm_year);
 216
 217         return 0;
 218 }
 219
 220 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
 221 {
 222         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 223         u8 date[7];
 224         int ret;
 225
 226         if ((dt->tm_year < 100) || (dt->tm_year > 199))
 227                 return -EINVAL;
 228
 229         /*
 230          * Here the read-only bits are written as "0".  I'm not sure if that
 231          * is sound.
 232          */
 233         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
 234         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
 235         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 236                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
 237         else
 238                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
 239                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
 240
 241         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
 242         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
 243         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
 244         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
 245
 246         dev_dbg(dev,
 247                 "%s: write 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n",
 248                 __func__,
 249                 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
 250
 251         ret = rx8025_write_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 252         if (ret < 0)
 253                 return ret;
 254
 255         return rx8025_reset_validity(rx8025->client);
 256 }
 257
 258 static int rx8025_init_client(struct i2c_client *client)
 259 {
 260         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 261         u8 ctrl[2], ctrl2;
 262         int need_clear = 0;
 263         int err;
 264
 265         err = rx8025_read_regs(rx8025->client, RX8025_REG_CTRL1, 2, ctrl);
 266         if (err)
 267                 goto out;
 268
 269         /* Keep test bit zero ! */
 270         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
 271
 272         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
 273                 dev_warn(&client->dev, "Alarm was detected\n");
 274                 need_clear = 1;
 275         }
 276
 277         if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
 278                 need_clear = 1;
 279
 280         if (need_clear) {
 281                 ctrl2 = ctrl[1];
 282                 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
 283                            RX8025_BIT_CTRL2_DAFG);
 284
 285                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
 286         }
 287 out:
 288         return err;
 289 }
 290
 291 /* Alarm support */
 292 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 293 {
 294         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 295         struct i2c_client *client = rx8025->client;
 296         u8 ald[2];
 297         int ctrl2, err;
 298
 299         if (client->irq <= 0)
 300                 return -EINVAL;
 301
 302         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
 303         if (err)
 304                 return err;
 305
 306         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 307         if (ctrl2 < 0)
 308                 return ctrl2;
 309
 310         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
 311                 __func__, ald[0], ald[1], ctrl2);
 312
 313         /* Hardware alarms precision is 1 minute! */
 314         t->time.tm_sec = 0;
 315         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 316         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 317                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
 318         else
 319                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
 320                         + (ald[1] & 0x20 ? 12 : 0);
 321
 322         dev_dbg(dev, "%s: date: %ds %dm %dh %dmd %dm %dy\n",
 323                 __func__,
 324                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 325                 t->time.tm_mday, t->time.tm_mon, t->time.tm_year);
 326         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
 327         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
 328
 329         return err;
 330 }
 331
 332 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 333 {
 334         struct i2c_client *client = to_i2c_client(dev);
 335         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 336         u8 ald[2];
 337         int err;
 338
 339         if (client->irq <= 0)
 340                 return -EINVAL;
 341
 342         /*
 343          * Hardware alarm precision is 1 minute!
 344          * round up to nearest minute
 345          */
 346         if (t->time.tm_sec) {
 347                 time64_t alarm_time = rtc_tm_to_time64(&t->time);
 348
 349                 alarm_time += 60 - t->time.tm_sec;
 350                 rtc_time64_to_tm(alarm_time, &t->time);
 351         }
 352
 353         ald[0] = bin2bcd(t->time.tm_min);
 354         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 355                 ald[1] = bin2bcd(t->time.tm_hour);
 356         else
 357                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
 358                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
 359
 360         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
 361
 362         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
 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         err = rx8025_write_regs(rx8025->client, RX8025_REG_ALDMIN, 2, ald);
 370         if (err)
 371                 return err;
 372
 373         if (t->enabled) {
 374                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
 375                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 376                                        rx8025->ctrl1);
 377                 if (err)
 378                         return err;
 379         }
 380
 381         return 0;
 382 }
 383
 384 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
 385 {
 386         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 387         u8 ctrl1;
 388         int err;
 389
 390         ctrl1 = rx8025->ctrl1;
 391         if (enabled)
 392                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
 393         else
 394                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 395
 396         if (ctrl1 != rx8025->ctrl1) {
 397                 rx8025->ctrl1 = ctrl1;
 398                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 399                                        rx8025->ctrl1);
 400                 if (err)
 401                         return err;
 402         }
 403         return 0;
 404 }
 405
 406 static const struct rtc_class_ops rx8025_rtc_ops = {
 407         .read_time = rx8025_get_time,
 408         .set_time = rx8025_set_time,
 409         .read_alarm = rx8025_read_alarm,
 410         .set_alarm = rx8025_set_alarm,
 411         .alarm_irq_enable = rx8025_alarm_irq_enable,
 412 };
 413
 414 /*
 415  * Clock precision adjustment support
 416  *
 417  * According to the RX8025 SA/NB application manual the frequency and
 418  * temperature characteristics can be approximated using the following
 419  * equation:
 420  *
 421  *   df = a * (ut - t)**2
 422  *
 423  *   df: Frequency deviation in any temperature
 424  *   a : Coefficient = (-35 +-5) * 10**-9
 425  *   ut: Ultimate temperature in degree = +25 +-5 degree
 426  *   t : Any temperature in degree
 427  *
 428  * Note that the clock adjustment in ppb must be entered (which is
 429  * the negative value of the deviation).
 430  */
 431 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
 432 {
 433         struct i2c_client *client = to_i2c_client(dev);
 434         int digoff;
 435
 436         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
 437         if (digoff < 0)
 438                 return digoff;
 439
 440         *adj = digoff >= 64 ? digoff - 128 : digoff;
 441         if (*adj > 0)
 442                 (*adj)--;
 443         *adj *= -RX8025_ADJ_RESOLUTION;
 444
 445         return 0;
 446 }
 447
 448 static int rx8025_set_clock_adjust(struct device *dev, int adj)
 449 {
 450         struct i2c_client *client = to_i2c_client(dev);
 451         u8 digoff;
 452         int err;
 453
 454         adj /= -RX8025_ADJ_RESOLUTION;
 455         if (adj > RX8025_ADJ_DATA_MAX)
 456                 adj = RX8025_ADJ_DATA_MAX;
 457         else if (adj < RX8025_ADJ_DATA_MIN)
 458                 adj = RX8025_ADJ_DATA_MIN;
 459         else if (adj > 0)
 460                 adj++;
 461         else if (adj < 0)
 462                 adj += 128;
 463         digoff = adj;
 464
 465         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
 466         if (err)
 467                 return err;
 468
 469         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
 470
 471         return 0;
 472 }
 473
 474 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
 475                                               struct device_attribute *attr,
 476                                               char *buf)
 477 {
 478         int err, adj;
 479
 480         err = rx8025_get_clock_adjust(dev, &adj);
 481         if (err)
 482                 return err;
 483
 484         return sprintf(buf, "%d\n", adj);
 485 }
 486
 487 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
 488                                                struct device_attribute *attr,
 489                                                const char *buf, size_t count)
 490 {
 491         int adj, err;
 492
 493         if (sscanf(buf, "%i", &adj) != 1)
 494                 return -EINVAL;
 495
 496         err = rx8025_set_clock_adjust(dev, adj);
 497
 498         return err ? err : count;
 499 }
 500
 501 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
 502                    rx8025_sysfs_show_clock_adjust,
 503                    rx8025_sysfs_store_clock_adjust);
 504
 505 static int rx8025_sysfs_register(struct device *dev)
 506 {
 507         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
 508 }
 509
 510 static void rx8025_sysfs_unregister(struct device *dev)
 511 {
 512         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
 513 }
 514
 515 static int rx8025_probe(struct i2c_client *client,
 516                         const struct i2c_device_id *id)
 517 {
 518         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 519         struct rx8025_data *rx8025;
 520         int err = 0;
 521
 522         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 523                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 524                 dev_err(&adapter->dev,
 525                         "doesn't support required functionality\n");
 526                 return -EIO;
 527         }
 528
 529         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 530         if (!rx8025)
 531                 return -ENOMEM;
 532
 533         rx8025->client = client;
 534         i2c_set_clientdata(client, rx8025);
 535
 536         err = rx8025_init_client(client);
 537         if (err)
 538                 return err;
 539
 540         rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
 541                                           &rx8025_rtc_ops, THIS_MODULE);
 542         if (IS_ERR(rx8025->rtc)) {
 543                 dev_err(&client->dev, "unable to register the class device\n");
 544                 return PTR_ERR(rx8025->rtc);
 545         }
 546
 547         if (client->irq > 0) {
 548                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 549                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 550                                                 rx8025_handle_irq,
 551                                                 IRQF_ONESHOT,
 552                                                 "rx8025", client);
 553                 if (err) {
 554                         dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
 555                         client->irq = 0;
 556                 }
 557         }
 558
 559         rx8025->rtc->max_user_freq = 1;
 560
 561         /* the rx8025 alarm only supports a minute accuracy */
 562         rx8025->rtc->uie_unsupported = 1;
 563
 564         err = rx8025_sysfs_register(&client->dev);
 565         return err;
 566 }
 567
 568 static int rx8025_remove(struct i2c_client *client)
 569 {
 570         rx8025_sysfs_unregister(&client->dev);
 571         return 0;
 572 }
 573
 574 static struct i2c_driver rx8025_driver = {
 575         .driver = {
 576                 .name = "rtc-rx8025",
 577         },
 578         .probe          = rx8025_probe,
 579         .remove         = rx8025_remove,
 580         .id_table       = rx8025_id,
 581 };
 582
 583 module_i2c_driver(rx8025_driver);
 584
 585 MODULE_AUTHOR("Wolfgang Grandegger <[email protected]>");
 586 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
 587 MODULE_LICENSE("GPL");