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/i2c.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/rtc.h>
  26
  27 /* Register definitions */
  28 #define RX8025_REG_SEC          0x00
  29 #define RX8025_REG_MIN          0x01
  30 #define RX8025_REG_HOUR         0x02
  31 #define RX8025_REG_WDAY         0x03
  32 #define RX8025_REG_MDAY         0x04
  33 #define RX8025_REG_MONTH        0x05
  34 #define RX8025_REG_YEAR         0x06
  35 #define RX8025_REG_DIGOFF       0x07
  36 #define RX8025_REG_ALWMIN       0x08
  37 #define RX8025_REG_ALWHOUR      0x09
  38 #define RX8025_REG_ALWWDAY      0x0a
  39 #define RX8025_REG_ALDMIN       0x0b
  40 #define RX8025_REG_ALDHOUR      0x0c
  41 /* 0x0d is reserved */
  42 #define RX8025_REG_CTRL1        0x0e
  43 #define RX8025_REG_CTRL2        0x0f
  44
  45 #define RX8025_BIT_CTRL1_CT     (7 << 0)
  46 /* 1 Hz periodic level irq */
  47 #define RX8025_BIT_CTRL1_CT_1HZ 4
  48 #define RX8025_BIT_CTRL1_TEST   (1 << 3)
  49 #define RX8025_BIT_CTRL1_1224   (1 << 5)
  50 #define RX8025_BIT_CTRL1_DALE   (1 << 6)
  51 #define RX8025_BIT_CTRL1_WALE   (1 << 7)
  52
  53 #define RX8025_BIT_CTRL2_DAFG   (1 << 0)
  54 #define RX8025_BIT_CTRL2_WAFG   (1 << 1)
  55 #define RX8025_BIT_CTRL2_CTFG   (1 << 2)
  56 #define RX8025_BIT_CTRL2_PON    (1 << 4)
  57 #define RX8025_BIT_CTRL2_XST    (1 << 5)
  58 #define RX8025_BIT_CTRL2_VDET   (1 << 6)
  59
  60 /* Clock precision adjustment */
  61 #define RX8025_ADJ_RESOLUTION   3050 /* in ppb */
  62 #define RX8025_ADJ_DATA_MAX     62
  63 #define RX8025_ADJ_DATA_MIN     -62
  64
  65 static const struct i2c_device_id rx8025_id[] = {
  66         { "rx8025", 0 },
  67         { }
  68 };
  69 MODULE_DEVICE_TABLE(i2c, rx8025_id);
  70
  71 struct rx8025_data {
  72         struct i2c_client *client;
  73         struct rtc_device *rtc;
  74         u8 ctrl1;
  75 };
  76
  77 static int rx8025_read_reg(struct i2c_client *client, int number, u8 *value)
  78 {
  79         int ret = i2c_smbus_read_byte_data(client, (number << 4) | 0x08);
  80
  81         if (ret < 0) {
  82                 dev_err(&client->dev, "Unable to read register #%d\n", number);
  83                 return ret;
  84         }
  85
  86         *value = ret;
  87         return 0;
  88 }
  89
  90 static int rx8025_read_regs(struct i2c_client *client,
  91                             int number, u8 length, u8 *values)
  92 {
  93         int ret = i2c_smbus_read_i2c_block_data(client, (number << 4) | 0x08,
  94                                                 length, values);
  95
  96         if (ret != length) {
  97                 dev_err(&client->dev, "Unable to read registers #%d..#%d\n",
  98                         number, number + length - 1);
  99                 return ret < 0 ? ret : -EIO;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static int rx8025_write_reg(struct i2c_client *client, int number, u8 value)
 106 {
 107         int ret = i2c_smbus_write_byte_data(client, number << 4, value);
 108
 109         if (ret)
 110                 dev_err(&client->dev, "Unable to write register #%d\n",
 111                         number);
 112
 113         return ret;
 114 }
 115
 116 static int rx8025_write_regs(struct i2c_client *client,
 117                              int number, u8 length, u8 *values)
 118 {
 119         int ret = i2c_smbus_write_i2c_block_data(client, (number << 4) | 0x08,
 120                                                  length, values);
 121
 122         if (ret)
 123                 dev_err(&client->dev, "Unable to write registers #%d..#%d\n",
 124                         number, number + length - 1);
 125
 126         return ret;
 127 }
 128
 129 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
 130 {
 131         struct i2c_client *client = dev_id;
 132         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 133         u8 status;
 134
 135         if (rx8025_read_reg(client, RX8025_REG_CTRL2, &status))
 136                 goto out;
 137
 138         if (!(status & RX8025_BIT_CTRL2_XST))
 139                 dev_warn(&client->dev, "Oscillation stop was detected,"
 140                          "you may have to readjust the clock\n");
 141
 142         if (status & RX8025_BIT_CTRL2_CTFG) {
 143                 /* periodic */
 144                 status &= ~RX8025_BIT_CTRL2_CTFG;
 145                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
 146         }
 147
 148         if (status & RX8025_BIT_CTRL2_DAFG) {
 149                 /* alarm */
 150                 status &= RX8025_BIT_CTRL2_DAFG;
 151                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
 152                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
 153                         goto out;
 154                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
 155         }
 156
 157         /* acknowledge IRQ */
 158         rx8025_write_reg(client, RX8025_REG_CTRL2,
 159                          status | RX8025_BIT_CTRL2_XST);
 160
 161 out:
 162         return IRQ_HANDLED;
 163 }
 164
 165 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
 166 {
 167         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 168         u8 date[7];
 169         int err;
 170
 171         err = rx8025_read_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 172         if (err)
 173                 return err;
 174
 175         dev_dbg(dev, "%s: read 0x%02x 0x%02x "
 176                 "0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n", __func__,
 177                 date[0], date[1], date[2], date[3], date[4],
 178                 date[5], date[6]);
 179
 180         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
 181         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
 182         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 183                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
 184         else
 185                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
 186                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
 187
 188         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
 189         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
 190         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]);
 191
 192         if (dt->tm_year < 70)
 193                 dt->tm_year += 100;
 194
 195         dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
 196                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 197                 dt->tm_mday, dt->tm_mon, dt->tm_year);
 198
 199         return rtc_valid_tm(dt);
 200 }
 201
 202 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
 203 {
 204         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 205         u8 date[7];
 206
 207         /*
 208          * BUG: The HW assumes every year that is a multiple of 4 to be a leap
 209          * year.  Next time this is wrong is 2100, which will not be a leap
 210          * year.
 211          */
 212
 213         /*
 214          * Here the read-only bits are written as "0".  I'm not sure if that
 215          * is sound.
 216          */
 217         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
 218         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
 219         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 220                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
 221         else
 222                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
 223                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
 224
 225         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
 226         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
 227         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
 228         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year % 100);
 229
 230         dev_dbg(dev,
 231                 "%s: write 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n",
 232                 __func__,
 233                 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
 234
 235         return rx8025_write_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 236 }
 237
 238 static int rx8025_init_client(struct i2c_client *client, int *need_reset)
 239 {
 240         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 241         u8 ctrl[2], ctrl2;
 242         int need_clear = 0;
 243         int err;
 244
 245         err = rx8025_read_regs(rx8025->client, RX8025_REG_CTRL1, 2, ctrl);
 246         if (err)
 247                 goto out;
 248
 249         /* Keep test bit zero ! */
 250         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
 251
 252         if (ctrl[1] & RX8025_BIT_CTRL2_PON) {
 253                 dev_warn(&client->dev, "power-on reset was detected, "
 254                          "you may have to readjust the clock\n");
 255                 *need_reset = 1;
 256         }
 257
 258         if (ctrl[1] & RX8025_BIT_CTRL2_VDET) {
 259                 dev_warn(&client->dev, "a power voltage drop was detected, "
 260                          "you may have to readjust the clock\n");
 261                 *need_reset = 1;
 262         }
 263
 264         if (!(ctrl[1] & RX8025_BIT_CTRL2_XST)) {
 265                 dev_warn(&client->dev, "Oscillation stop was detected,"
 266                          "you may have to readjust the clock\n");
 267                 *need_reset = 1;
 268         }
 269
 270         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
 271                 dev_warn(&client->dev, "Alarm was detected\n");
 272                 need_clear = 1;
 273         }
 274
 275         if (!(ctrl[1] & RX8025_BIT_CTRL2_CTFG))
 276                 need_clear = 1;
 277
 278         if (*need_reset || need_clear) {
 279                 ctrl2 = ctrl[0];
 280                 ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET |
 281                            RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
 282                            RX8025_BIT_CTRL2_DAFG);
 283                 ctrl2 |= RX8025_BIT_CTRL2_XST;
 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 ctrl2, ald[2];
 297         int 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         err = rx8025_read_reg(client, RX8025_REG_CTRL2, &ctrl2);
 307         if (err)
 308                 return err;
 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         u8 digoff;
 430         int err;
 431
 432         err = rx8025_read_reg(client, RX8025_REG_DIGOFF, &digoff);
 433         if (err)
 434                 return err;
 435
 436         *adj = digoff >= 64 ? digoff - 128 : digoff;
 437         if (*adj > 0)
 438                 (*adj)--;
 439         *adj *= -RX8025_ADJ_RESOLUTION;
 440
 441         return 0;
 442 }
 443
 444 static int rx8025_set_clock_adjust(struct device *dev, int adj)
 445 {
 446         struct i2c_client *client = to_i2c_client(dev);
 447         u8 digoff;
 448         int err;
 449
 450         adj /= -RX8025_ADJ_RESOLUTION;
 451         if (adj > RX8025_ADJ_DATA_MAX)
 452                 adj = RX8025_ADJ_DATA_MAX;
 453         else if (adj < RX8025_ADJ_DATA_MIN)
 454                 adj = RX8025_ADJ_DATA_MIN;
 455         else if (adj > 0)
 456                 adj++;
 457         else if (adj < 0)
 458                 adj += 128;
 459         digoff = adj;
 460
 461         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
 462         if (err)
 463                 return err;
 464
 465         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
 466
 467         return 0;
 468 }
 469
 470 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
 471                                               struct device_attribute *attr,
 472                                               char *buf)
 473 {
 474         int err, adj;
 475
 476         err = rx8025_get_clock_adjust(dev, &adj);
 477         if (err)
 478                 return err;
 479
 480         return sprintf(buf, "%d\n", adj);
 481 }
 482
 483 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
 484                                                struct device_attribute *attr,
 485                                                const char *buf, size_t count)
 486 {
 487         int adj, err;
 488
 489         if (sscanf(buf, "%i", &adj) != 1)
 490                 return -EINVAL;
 491
 492         err = rx8025_set_clock_adjust(dev, adj);
 493
 494         return err ? err : count;
 495 }
 496
 497 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
 498                    rx8025_sysfs_show_clock_adjust,
 499                    rx8025_sysfs_store_clock_adjust);
 500
 501 static int rx8025_sysfs_register(struct device *dev)
 502 {
 503         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
 504 }
 505
 506 static void rx8025_sysfs_unregister(struct device *dev)
 507 {
 508         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
 509 }
 510
 511 static int rx8025_probe(struct i2c_client *client,
 512                         const struct i2c_device_id *id)
 513 {
 514         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 515         struct rx8025_data *rx8025;
 516         int err = 0, need_reset = 0;
 517
 518         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 519                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 520                 dev_err(&adapter->dev,
 521                         "doesn't support required functionality\n");
 522                 return -EIO;
 523         }
 524
 525         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 526         if (!rx8025) {
 527                 return -ENOMEM;
 528         }
 529
 530         rx8025->client = client;
 531         i2c_set_clientdata(client, rx8025);
 532
 533         err = rx8025_init_client(client, &need_reset);
 534         if (err)
 535                 return err;
 536
 537         if (need_reset) {
 538                 struct rtc_time tm;
 539                 dev_info(&client->dev,
 540                          "bad conditions detected, resetting date\n");
 541                 rtc_time_to_tm(0, &tm); /* 1970/1/1 */
 542                 rx8025_set_time(&client->dev, &tm);
 543         }
 544
 545         rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
 546                                           &rx8025_rtc_ops, THIS_MODULE);
 547         if (IS_ERR(rx8025->rtc)) {
 548                 dev_err(&client->dev, "unable to register the class device\n");
 549                 return PTR_ERR(rx8025->rtc);
 550         }
 551
 552         if (client->irq > 0) {
 553                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 554                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 555                                                 rx8025_handle_irq, 0, "rx8025",
 556                                                 client);
 557                 if (err) {
 558                         dev_err(&client->dev, "unable to request IRQ\n");
 559                         return err;
 560                 }
 561         }
 562
 563         rx8025->rtc->irq_freq = 1;
 564         rx8025->rtc->max_user_freq = 1;
 565
 566         err = rx8025_sysfs_register(&client->dev);
 567         return err;
 568 }
 569
 570 static int rx8025_remove(struct i2c_client *client)
 571 {
 572         rx8025_sysfs_unregister(&client->dev);
 573         return 0;
 574 }
 575
 576 static struct i2c_driver rx8025_driver = {
 577         .driver = {
 578                 .name = "rtc-rx8025",
 579         },
 580         .probe          = rx8025_probe,
 581         .remove         = rx8025_remove,
 582         .id_table       = rx8025_id,
 583 };
 584
 585 module_i2c_driver(rx8025_driver);
 586
 587 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 588 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
 589 MODULE_LICENSE("GPL");