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         { "rv8803", 1 },
  69         { }
  70 };
  71 MODULE_DEVICE_TABLE(i2c, rx8025_id);
  72
  73 struct rx8025_data {
  74         struct i2c_client *client;
  75         struct rtc_device *rtc;
  76         u8 ctrl1;
  77 };
  78
  79 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
  80 {
  81         return i2c_smbus_read_byte_data(client, number << 4);
  82 }
  83
  84 static int rx8025_read_regs(const struct i2c_client *client,
  85                             u8 number, u8 length, u8 *values)
  86 {
  87         int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
  88                                                 values);
  89         if (ret != length)
  90                 return ret < 0 ? ret : -EIO;
  91
  92         return 0;
  93 }
  94
  95 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
  96                             u8 value)
  97 {
  98         return i2c_smbus_write_byte_data(client, number << 4, value);
  99 }
 100
 101 static s32 rx8025_write_regs(const struct i2c_client *client,
 102                              u8 number, u8 length, const u8 *values)
 103 {
 104         return i2c_smbus_write_i2c_block_data(client, number << 4,
 105                                               length, values);
 106 }
 107
 108 static int rx8025_check_validity(struct device *dev)
 109 {
 110         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 111         int ctrl2;
 112
 113         ctrl2 = rx8025_read_reg(rx8025->client, RX8025_REG_CTRL2);
 114         if (ctrl2 < 0)
 115                 return ctrl2;
 116
 117         if (ctrl2 & RX8025_BIT_CTRL2_VDET)
 118                 dev_warn(dev, "power voltage drop detected\n");
 119
 120         if (ctrl2 & RX8025_BIT_CTRL2_PON) {
 121                 dev_warn(dev, "power-on reset detected, date is invalid\n");
 122                 return -EINVAL;
 123         }
 124
 125         if (!(ctrl2 & RX8025_BIT_CTRL2_XST)) {
 126                 dev_warn(dev, "crystal stopped, date is invalid\n");
 127                 return -EINVAL;
 128         }
 129
 130         return 0;
 131 }
 132
 133 static int rx8025_reset_validity(struct i2c_client *client)
 134 {
 135         int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 136
 137         if (ctrl2 < 0)
 138                 return ctrl2;
 139
 140         ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
 141
 142         return rx8025_write_reg(client, RX8025_REG_CTRL2,
 143                                 ctrl2 | RX8025_BIT_CTRL2_XST);
 144 }
 145
 146 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
 147 {
 148         struct i2c_client *client = dev_id;
 149         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 150         int status;
 151
 152         status = rx8025_read_reg(client, RX8025_REG_CTRL2);
 153         if (status < 0)
 154                 goto out;
 155
 156         if (!(status & RX8025_BIT_CTRL2_XST))
 157                 dev_warn(&client->dev, "Oscillation stop was detected,"
 158                          "you may have to readjust the clock\n");
 159
 160         if (status & RX8025_BIT_CTRL2_CTFG) {
 161                 /* periodic */
 162                 status &= ~RX8025_BIT_CTRL2_CTFG;
 163                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
 164         }
 165
 166         if (status & RX8025_BIT_CTRL2_DAFG) {
 167                 /* alarm */
 168                 status &= RX8025_BIT_CTRL2_DAFG;
 169                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
 170                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
 171                         goto out;
 172                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
 173         }
 174
 175 out:
 176         return IRQ_HANDLED;
 177 }
 178
 179 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
 180 {
 181         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 182         u8 date[7];
 183         int err;
 184
 185         err = rx8025_check_validity(dev);
 186         if (err)
 187                 return err;
 188
 189         err = rx8025_read_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 190         if (err)
 191                 return err;
 192
 193         dev_dbg(dev, "%s: read 0x%02x 0x%02x "
 194                 "0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n", __func__,
 195                 date[0], date[1], date[2], date[3], date[4],
 196                 date[5], date[6]);
 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 %ds %dm %dh %dmd %dm %dy\n", __func__,
 211                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 212                 dt->tm_mday, dt->tm_mon, dt->tm_year);
 213
 214         return rtc_valid_tm(dt);
 215 }
 216
 217 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
 218 {
 219         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 220         u8 date[7];
 221         int ret;
 222
 223         if ((dt->tm_year < 100) || (dt->tm_year > 199))
 224                 return -EINVAL;
 225
 226         /*
 227          * Here the read-only bits are written as "0".  I'm not sure if that
 228          * is sound.
 229          */
 230         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
 231         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
 232         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 233                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
 234         else
 235                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
 236                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
 237
 238         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
 239         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
 240         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
 241         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
 242
 243         dev_dbg(dev,
 244                 "%s: write 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n",
 245                 __func__,
 246                 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
 247
 248         ret = rx8025_write_regs(rx8025->client, RX8025_REG_SEC, 7, date);
 249         if (ret < 0)
 250                 return ret;
 251
 252         return rx8025_reset_validity(rx8025->client);
 253 }
 254
 255 static int rx8025_init_client(struct i2c_client *client)
 256 {
 257         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 258         u8 ctrl[2], ctrl2;
 259         int need_clear = 0;
 260         int err;
 261
 262         err = rx8025_read_regs(rx8025->client, RX8025_REG_CTRL1, 2, ctrl);
 263         if (err)
 264                 goto out;
 265
 266         /* Keep test bit zero ! */
 267         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
 268
 269         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
 270                 dev_warn(&client->dev, "Alarm was detected\n");
 271                 need_clear = 1;
 272         }
 273
 274         if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
 275                 need_clear = 1;
 276
 277         if (need_clear) {
 278                 ctrl2 = ctrl[1];
 279                 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
 280                            RX8025_BIT_CTRL2_DAFG);
 281
 282                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
 283         }
 284 out:
 285         return err;
 286 }
 287
 288 /* Alarm support */
 289 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 290 {
 291         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 292         struct i2c_client *client = rx8025->client;
 293         u8 ald[2];
 294         int ctrl2, err;
 295
 296         if (client->irq <= 0)
 297                 return -EINVAL;
 298
 299         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
 300         if (err)
 301                 return err;
 302
 303         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 304         if (ctrl2 < 0)
 305                 return ctrl2;
 306
 307         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
 308                 __func__, ald[0], ald[1], ctrl2);
 309
 310         /* Hardware alarms precision is 1 minute! */
 311         t->time.tm_sec = 0;
 312         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 313         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 314                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
 315         else
 316                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
 317                         + (ald[1] & 0x20 ? 12 : 0);
 318
 319         t->time.tm_wday = -1;
 320         t->time.tm_mday = -1;
 321         t->time.tm_mon = -1;
 322         t->time.tm_year = -1;
 323
 324         dev_dbg(dev, "%s: date: %ds %dm %dh %dmd %dm %dy\n",
 325                 __func__,
 326                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 327                 t->time.tm_mday, t->time.tm_mon, t->time.tm_year);
 328         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
 329         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
 330
 331         return err;
 332 }
 333
 334 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 335 {
 336         struct i2c_client *client = to_i2c_client(dev);
 337         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 338         u8 ald[2];
 339         int err;
 340
 341         if (client->irq <= 0)
 342                 return -EINVAL;
 343
 344         /* Hardware alarm precision is 1 minute! */
 345         ald[0] = bin2bcd(t->time.tm_min);
 346         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 347                 ald[1] = bin2bcd(t->time.tm_hour);
 348         else
 349                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
 350                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
 351
 352         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
 353
 354         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
 355                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 356                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 357                                        rx8025->ctrl1);
 358                 if (err)
 359                         return err;
 360         }
 361         err = rx8025_write_regs(rx8025->client, RX8025_REG_ALDMIN, 2, ald);
 362         if (err)
 363                 return err;
 364
 365         if (t->enabled) {
 366                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
 367                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 368                                        rx8025->ctrl1);
 369                 if (err)
 370                         return err;
 371         }
 372
 373         return 0;
 374 }
 375
 376 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
 377 {
 378         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 379         u8 ctrl1;
 380         int err;
 381
 382         ctrl1 = rx8025->ctrl1;
 383         if (enabled)
 384                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
 385         else
 386                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 387
 388         if (ctrl1 != rx8025->ctrl1) {
 389                 rx8025->ctrl1 = ctrl1;
 390                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
 391                                        rx8025->ctrl1);
 392                 if (err)
 393                         return err;
 394         }
 395         return 0;
 396 }
 397
 398 static struct rtc_class_ops rx8025_rtc_ops = {
 399         .read_time = rx8025_get_time,
 400         .set_time = rx8025_set_time,
 401         .read_alarm = rx8025_read_alarm,
 402         .set_alarm = rx8025_set_alarm,
 403         .alarm_irq_enable = rx8025_alarm_irq_enable,
 404 };
 405
 406 /*
 407  * Clock precision adjustment support
 408  *
 409  * According to the RX8025 SA/NB application manual the frequency and
 410  * temperature characteristics can be approximated using the following
 411  * equation:
 412  *
 413  *   df = a * (ut - t)**2
 414  *
 415  *   df: Frequency deviation in any temperature
 416  *   a : Coefficient = (-35 +-5) * 10**-9
 417  *   ut: Ultimate temperature in degree = +25 +-5 degree
 418  *   t : Any temperature in degree
 419  *
 420  * Note that the clock adjustment in ppb must be entered (which is
 421  * the negative value of the deviation).
 422  */
 423 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
 424 {
 425         struct i2c_client *client = to_i2c_client(dev);
 426         int digoff;
 427
 428         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
 429         if (digoff < 0)
 430                 return digoff;
 431
 432         *adj = digoff >= 64 ? digoff - 128 : digoff;
 433         if (*adj > 0)
 434                 (*adj)--;
 435         *adj *= -RX8025_ADJ_RESOLUTION;
 436
 437         return 0;
 438 }
 439
 440 static int rx8025_set_clock_adjust(struct device *dev, int adj)
 441 {
 442         struct i2c_client *client = to_i2c_client(dev);
 443         u8 digoff;
 444         int err;
 445
 446         adj /= -RX8025_ADJ_RESOLUTION;
 447         if (adj > RX8025_ADJ_DATA_MAX)
 448                 adj = RX8025_ADJ_DATA_MAX;
 449         else if (adj < RX8025_ADJ_DATA_MIN)
 450                 adj = RX8025_ADJ_DATA_MIN;
 451         else if (adj > 0)
 452                 adj++;
 453         else if (adj < 0)
 454                 adj += 128;
 455         digoff = adj;
 456
 457         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
 458         if (err)
 459                 return err;
 460
 461         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
 462
 463         return 0;
 464 }
 465
 466 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
 467                                               struct device_attribute *attr,
 468                                               char *buf)
 469 {
 470         int err, adj;
 471
 472         err = rx8025_get_clock_adjust(dev, &adj);
 473         if (err)
 474                 return err;
 475
 476         return sprintf(buf, "%d\n", adj);
 477 }
 478
 479 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
 480                                                struct device_attribute *attr,
 481                                                const char *buf, size_t count)
 482 {
 483         int adj, err;
 484
 485         if (sscanf(buf, "%i", &adj) != 1)
 486                 return -EINVAL;
 487
 488         err = rx8025_set_clock_adjust(dev, adj);
 489
 490         return err ? err : count;
 491 }
 492
 493 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
 494                    rx8025_sysfs_show_clock_adjust,
 495                    rx8025_sysfs_store_clock_adjust);
 496
 497 static int rx8025_sysfs_register(struct device *dev)
 498 {
 499         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
 500 }
 501
 502 static void rx8025_sysfs_unregister(struct device *dev)
 503 {
 504         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
 505 }
 506
 507 static int rx8025_probe(struct i2c_client *client,
 508                         const struct i2c_device_id *id)
 509 {
 510         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 511         struct rx8025_data *rx8025;
 512         int err = 0;
 513
 514         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 515                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 516                 dev_err(&adapter->dev,
 517                         "doesn't support required functionality\n");
 518                 return -EIO;
 519         }
 520
 521         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 522         if (!rx8025)
 523                 return -ENOMEM;
 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");