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         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 rtc_valid_tm(dt);
 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         t->time.tm_wday = -1;
 323         t->time.tm_mday = -1;
 324         t->time.tm_mon = -1;
 325         t->time.tm_year = -1;
 326
 327         dev_dbg(dev, "%s: date: %ds %dm %dh %dmd %dm %dy\n",
 328                 __func__,
 329                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 330                 t->time.tm_mday, t->time.tm_mon, t->time.tm_year);
 331         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
 332         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
 333
 334         return err;
 335 }
 336
 337 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 338 {
 339         struct i2c_client *client = to_i2c_client(dev);
 340         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 341         u8 ald[2];
 342         int err;
 343
 344         if (client->irq <= 0)
 345                 return -EINVAL;
 346
 347         /* Hardware alarm precision is 1 minute! */
 348         ald[0] = bin2bcd(t->time.tm_min);
 349         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 350                 ald[1] = bin2bcd(t->time.tm_hour);
 351         else
 352                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
 353                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
 354
 355         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
 356
 357         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
 358                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 359                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 360                                        rx8025->ctrl1);
 361                 if (err)
 362                         return err;
 363         }
 364         err = rx8025_write_regs(rx8025->client, RX8025_REG_ALDMIN, 2, ald);
 365         if (err)
 366                 return err;
 367
 368         if (t->enabled) {
 369                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
 370                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 371                                        rx8025->ctrl1);
 372                 if (err)
 373                         return err;
 374         }
 375
 376         return 0;
 377 }
 378
 379 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
 380 {
 381         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 382         u8 ctrl1;
 383         int err;
 384
 385         ctrl1 = rx8025->ctrl1;
 386         if (enabled)
 387                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
 388         else
 389                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 390
 391         if (ctrl1 != rx8025->ctrl1) {
 392                 rx8025->ctrl1 = ctrl1;
 393                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 394                                        rx8025->ctrl1);
 395                 if (err)
 396                         return err;
 397         }
 398         return 0;
 399 }
 400
 401 static struct rtc_class_ops rx8025_rtc_ops = {
 402         .read_time = rx8025_get_time,
 403         .set_time = rx8025_set_time,
 404         .read_alarm = rx8025_read_alarm,
 405         .set_alarm = rx8025_set_alarm,
 406         .alarm_irq_enable = rx8025_alarm_irq_enable,
 407 };
 408
 409 /*
 410  * Clock precision adjustment support
 411  *
 412  * According to the RX8025 SA/NB application manual the frequency and
 413  * temperature characteristics can be approximated using the following
 414  * equation:
 415  *
 416  *   df = a * (ut - t)**2
 417  *
 418  *   df: Frequency deviation in any temperature
 419  *   a : Coefficient = (-35 +-5) * 10**-9
 420  *   ut: Ultimate temperature in degree = +25 +-5 degree
 421  *   t : Any temperature in degree
 422  *
 423  * Note that the clock adjustment in ppb must be entered (which is
 424  * the negative value of the deviation).
 425  */
 426 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
 427 {
 428         struct i2c_client *client = to_i2c_client(dev);
 429         int digoff;
 430
 431         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
 432         if (digoff < 0)
 433                 return digoff;
 434
 435         *adj = digoff >= 64 ? digoff - 128 : digoff;
 436         if (*adj > 0)
 437                 (*adj)--;
 438         *adj *= -RX8025_ADJ_RESOLUTION;
 439
 440         return 0;
 441 }
 442
 443 static int rx8025_set_clock_adjust(struct device *dev, int adj)
 444 {
 445         struct i2c_client *client = to_i2c_client(dev);
 446         u8 digoff;
 447         int err;
 448
 449         adj /= -RX8025_ADJ_RESOLUTION;
 450         if (adj > RX8025_ADJ_DATA_MAX)
 451                 adj = RX8025_ADJ_DATA_MAX;
 452         else if (adj < RX8025_ADJ_DATA_MIN)
 453                 adj = RX8025_ADJ_DATA_MIN;
 454         else if (adj > 0)
 455                 adj++;
 456         else if (adj < 0)
 457                 adj += 128;
 458         digoff = adj;
 459
 460         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
 461         if (err)
 462                 return err;
 463
 464         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
 465
 466         return 0;
 467 }
 468
 469 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
 470                                               struct device_attribute *attr,
 471                                               char *buf)
 472 {
 473         int err, adj;
 474
 475         err = rx8025_get_clock_adjust(dev, &adj);
 476         if (err)
 477                 return err;
 478
 479         return sprintf(buf, "%d\n", adj);
 480 }
 481
 482 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
 483                                                struct device_attribute *attr,
 484                                                const char *buf, size_t count)
 485 {
 486         int adj, err;
 487
 488         if (sscanf(buf, "%i", &adj) != 1)
 489                 return -EINVAL;
 490
 491         err = rx8025_set_clock_adjust(dev, adj);
 492
 493         return err ? err : count;
 494 }
 495
 496 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
 497                    rx8025_sysfs_show_clock_adjust,
 498                    rx8025_sysfs_store_clock_adjust);
 499
 500 static int rx8025_sysfs_register(struct device *dev)
 501 {
 502         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
 503 }
 504
 505 static void rx8025_sysfs_unregister(struct device *dev)
 506 {
 507         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
 508 }
 509
 510 static int rx8025_probe(struct i2c_client *client,
 511                         const struct i2c_device_id *id)
 512 {
 513         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 514         struct rx8025_data *rx8025;
 515         int err = 0;
 516
 517         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 518                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 519                 dev_err(&adapter->dev,
 520                         "doesn't support required functionality\n");
 521                 return -EIO;
 522         }
 523
 524         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 525         if (!rx8025)
 526                 return -ENOMEM;
 527
 528         rx8025->client = client;
 529         i2c_set_clientdata(client, rx8025);
 530
 531         err = rx8025_init_client(client);
 532         if (err)
 533                 return err;
 534
 535         rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
 536                                           &rx8025_rtc_ops, THIS_MODULE);
 537         if (IS_ERR(rx8025->rtc)) {
 538                 dev_err(&client->dev, "unable to register the class device\n");
 539                 return PTR_ERR(rx8025->rtc);
 540         }
 541
 542         if (client->irq > 0) {
 543                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 544                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 545                                                 rx8025_handle_irq,
 546                                                 IRQF_ONESHOT,
 547                                                 "rx8025", client);
 548                 if (err) {
 549                         dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
 550                         client->irq = 0;
 551                 }
 552         }
 553
 554         rx8025->rtc->max_user_freq = 1;
 555
 556         err = rx8025_sysfs_register(&client->dev);
 557         return err;
 558 }
 559
 560 static int rx8025_remove(struct i2c_client *client)
 561 {
 562         rx8025_sysfs_unregister(&client->dev);
 563         return 0;
 564 }
 565
 566 static struct i2c_driver rx8025_driver = {
 567         .driver = {
 568                 .name = "rtc-rx8025",
 569         },
 570         .probe          = rx8025_probe,
 571         .remove         = rx8025_remove,
 572         .id_table       = rx8025_id,
 573 };
 574
 575 module_i2c_driver(rx8025_driver);
 576
 577 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 578 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
 579 MODULE_LICENSE("GPL");