drivers/rtc/rtc-rx8025.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for Epson's RTC module RX-8025 SA/NB
   4  *
   5  * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
   6  *
   7  * Copyright (C) 2005 by Digi International Inc.
   8  * All rights reserved.
   9  *
  10  * Modified by fengjh at rising.com.cn
  11  * <lm-sensors@lm-sensors.org>
  12  * 2006.11
  13  *
  14  * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
  15  * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
  16  * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
  17  */
  18 #include <linux/bcd.h>
  19 #include <linux/bitops.h>
  20 #include <linux/i2c.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/rtc.h>
  24
  25 /* Register definitions */
  26 #define RX8025_REG_SEC          0x00
  27 #define RX8025_REG_MIN          0x01
  28 #define RX8025_REG_HOUR         0x02
  29 #define RX8025_REG_WDAY         0x03
  30 #define RX8025_REG_MDAY         0x04
  31 #define RX8025_REG_MONTH        0x05
  32 #define RX8025_REG_YEAR         0x06
  33 #define RX8025_REG_DIGOFF       0x07
  34 #define RX8025_REG_ALWMIN       0x08
  35 #define RX8025_REG_ALWHOUR      0x09
  36 #define RX8025_REG_ALWWDAY      0x0a
  37 #define RX8025_REG_ALDMIN       0x0b
  38 #define RX8025_REG_ALDHOUR      0x0c
  39 /* 0x0d is reserved */
  40 #define RX8025_REG_CTRL1        0x0e
  41 #define RX8025_REG_CTRL2        0x0f
  42
  43 #define RX8025_BIT_CTRL1_CT     (7 << 0)
  44 /* 1 Hz periodic level irq */
  45 #define RX8025_BIT_CTRL1_CT_1HZ 4
  46 #define RX8025_BIT_CTRL1_TEST   BIT(3)
  47 #define RX8025_BIT_CTRL1_1224   BIT(5)
  48 #define RX8025_BIT_CTRL1_DALE   BIT(6)
  49 #define RX8025_BIT_CTRL1_WALE   BIT(7)
  50
  51 #define RX8025_BIT_CTRL2_DAFG   BIT(0)
  52 #define RX8025_BIT_CTRL2_WAFG   BIT(1)
  53 #define RX8025_BIT_CTRL2_CTFG   BIT(2)
  54 #define RX8025_BIT_CTRL2_PON    BIT(4)
  55 #define RX8025_BIT_CTRL2_XST    BIT(5)
  56 #define RX8025_BIT_CTRL2_VDET   BIT(6)
  57
  58 #define RX8035_BIT_HOUR_1224    BIT(7)
  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 enum rx_model {
  66         model_rx_unknown,
  67         model_rx_8025,
  68         model_rx_8035,
  69         model_last
  70 };
  71
  72 static const struct i2c_device_id rx8025_id[] = {
  73         { "rx8025", model_rx_8025 },
  74         { "rx8035", model_rx_8035 },
  75         { }
  76 };
  77 MODULE_DEVICE_TABLE(i2c, rx8025_id);
  78
  79 struct rx8025_data {
  80         struct rtc_device *rtc;
  81         enum rx_model model;
  82         u8 ctrl1;
  83         int is_24;
  84 };
  85
  86 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
  87 {
  88         return i2c_smbus_read_byte_data(client, number << 4);
  89 }
  90
  91 static int rx8025_read_regs(const struct i2c_client *client,
  92                             u8 number, u8 length, u8 *values)
  93 {
  94         int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
  95                                                 values);
  96         if (ret != length)
  97                 return ret < 0 ? ret : -EIO;
  98
  99         return 0;
 100 }
 101
 102 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
 103                             u8 value)
 104 {
 105         return i2c_smbus_write_byte_data(client, number << 4, value);
 106 }
 107
 108 static s32 rx8025_write_regs(const struct i2c_client *client,
 109                              u8 number, u8 length, const u8 *values)
 110 {
 111         return i2c_smbus_write_i2c_block_data(client, number << 4,
 112                                               length, values);
 113 }
 114
 115 static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
 116 {
 117         int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
 118         /* XSTP bit has different polarity on RX-8025 vs RX-8035.
 119          * RX-8025: 0 == oscillator stopped
 120          * RX-8035: 1 == oscillator stopped
 121          */
 122
 123         if (model == model_rx_8025)
 124                 xstp = !xstp;
 125
 126         return xstp;
 127 }
 128
 129 static int rx8025_check_validity(struct device *dev)
 130 {
 131         struct i2c_client *client = to_i2c_client(dev);
 132         struct rx8025_data *drvdata = dev_get_drvdata(dev);
 133         int ctrl2;
 134         int xstp;
 135
 136         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 137         if (ctrl2 < 0)
 138                 return ctrl2;
 139
 140         if (ctrl2 & RX8025_BIT_CTRL2_VDET)
 141                 dev_warn(dev, "power voltage drop detected\n");
 142
 143         if (ctrl2 & RX8025_BIT_CTRL2_PON) {
 144                 dev_warn(dev, "power-on reset detected, date is invalid\n");
 145                 return -EINVAL;
 146         }
 147
 148         xstp = rx8025_is_osc_stopped(drvdata->model, ctrl2);
 149         if (xstp) {
 150                 dev_warn(dev, "crystal stopped, date is invalid\n");
 151                 return -EINVAL;
 152         }
 153
 154         return 0;
 155 }
 156
 157 static int rx8025_reset_validity(struct i2c_client *client)
 158 {
 159         struct rx8025_data *drvdata = i2c_get_clientdata(client);
 160         int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 161
 162         if (ctrl2 < 0)
 163                 return ctrl2;
 164
 165         ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
 166
 167         if (drvdata->model == model_rx_8025)
 168                 ctrl2 |= RX8025_BIT_CTRL2_XST;
 169         else
 170                 ctrl2 &= ~(RX8025_BIT_CTRL2_XST);
 171
 172         return rx8025_write_reg(client, RX8025_REG_CTRL2,
 173                                 ctrl2);
 174 }
 175
 176 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
 177 {
 178         struct i2c_client *client = dev_id;
 179         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 180         int status, xstp;
 181
 182         rtc_lock(rx8025->rtc);
 183         status = rx8025_read_reg(client, RX8025_REG_CTRL2);
 184         if (status < 0)
 185                 goto out;
 186
 187         xstp = rx8025_is_osc_stopped(rx8025->model, status);
 188         if (xstp)
 189                 dev_warn(&client->dev, "Oscillation stop was detected,"
 190                          "you may have to readjust the clock\n");
 191
 192         if (status & RX8025_BIT_CTRL2_CTFG) {
 193                 /* periodic */
 194                 status &= ~RX8025_BIT_CTRL2_CTFG;
 195                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
 196         }
 197
 198         if (status & RX8025_BIT_CTRL2_DAFG) {
 199                 /* alarm */
 200                 status &= RX8025_BIT_CTRL2_DAFG;
 201                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
 202                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
 203                         goto out;
 204                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
 205         }
 206
 207 out:
 208         rtc_unlock(rx8025->rtc);
 209
 210         return IRQ_HANDLED;
 211 }
 212
 213 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
 214 {
 215         struct i2c_client *client = to_i2c_client(dev);
 216         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 217         u8 date[7];
 218         int err;
 219
 220         err = rx8025_check_validity(dev);
 221         if (err)
 222                 return err;
 223
 224         err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
 225         if (err)
 226                 return err;
 227
 228         dev_dbg(dev, "%s: read %7ph\n", __func__, date);
 229
 230         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
 231         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
 232         if (rx8025->is_24)
 233                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
 234         else
 235                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
 236                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
 237
 238         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
 239         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
 240         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
 241
 242         dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
 243
 244         return 0;
 245 }
 246
 247 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
 248 {
 249         struct i2c_client *client = to_i2c_client(dev);
 250         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 251         u8 date[7];
 252         int ret;
 253
 254         /*
 255          * Here the read-only bits are written as "0".  I'm not sure if that
 256          * is sound.
 257          */
 258         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
 259         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
 260         if (rx8025->is_24)
 261                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
 262         else
 263                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
 264                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
 265
 266         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
 267         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
 268         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
 269         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
 270
 271         dev_dbg(dev, "%s: write %7ph\n", __func__, date);
 272
 273         ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
 274         if (ret < 0)
 275                 return ret;
 276
 277         return rx8025_reset_validity(client);
 278 }
 279
 280 static int rx8025_init_client(struct i2c_client *client)
 281 {
 282         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 283         u8 ctrl[2], ctrl2;
 284         int need_clear = 0;
 285         int hour_reg;
 286         int err;
 287
 288         err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
 289         if (err)
 290                 goto out;
 291
 292         /* Keep test bit zero ! */
 293         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
 294
 295         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
 296                 dev_warn(&client->dev, "Alarm was detected\n");
 297                 need_clear = 1;
 298         }
 299
 300         if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
 301                 need_clear = 1;
 302
 303         if (need_clear) {
 304                 ctrl2 = ctrl[1];
 305                 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
 306                            RX8025_BIT_CTRL2_DAFG);
 307
 308                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
 309         }
 310
 311         if (rx8025->model == model_rx_8035) {
 312                 /* In RX-8035, 12/24 flag is in the hour register */
 313                 hour_reg = rx8025_read_reg(client, RX8025_REG_HOUR);
 314                 if (hour_reg < 0)
 315                         return hour_reg;
 316                 rx8025->is_24 = (hour_reg & RX8035_BIT_HOUR_1224);
 317         } else {
 318                 rx8025->is_24 = (ctrl[1] & RX8025_BIT_CTRL1_1224);
 319         }
 320 out:
 321         return err;
 322 }
 323
 324 /* Alarm support */
 325 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 326 {
 327         struct i2c_client *client = to_i2c_client(dev);
 328         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 329         u8 ald[2];
 330         int ctrl2, err;
 331
 332         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
 333         if (err)
 334                 return err;
 335
 336         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 337         if (ctrl2 < 0)
 338                 return ctrl2;
 339
 340         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
 341                 __func__, ald[0], ald[1], ctrl2);
 342
 343         /* Hardware alarms precision is 1 minute! */
 344         t->time.tm_sec = 0;
 345         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 346         if (rx8025->is_24)
 347                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
 348         else
 349                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
 350                         + (ald[1] & 0x20 ? 12 : 0);
 351
 352         dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
 353         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
 354         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
 355
 356         return err;
 357 }
 358
 359 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 360 {
 361         struct i2c_client *client = to_i2c_client(dev);
 362         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 363         u8 ald[2];
 364         int err;
 365
 366         ald[0] = bin2bcd(t->time.tm_min);
 367         if (rx8025->is_24)
 368                 ald[1] = bin2bcd(t->time.tm_hour);
 369         else
 370                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
 371                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
 372
 373         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
 374
 375         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
 376                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 377                 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
 378                                        rx8025->ctrl1);
 379                 if (err)
 380                         return err;
 381         }
 382         err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
 383         if (err)
 384                 return err;
 385
 386         if (t->enabled) {
 387                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
 388                 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
 389                                        rx8025->ctrl1);
 390                 if (err)
 391                         return err;
 392         }
 393
 394         return 0;
 395 }
 396
 397 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
 398 {
 399         struct i2c_client *client = to_i2c_client(dev);
 400         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 401         u8 ctrl1;
 402         int err;
 403
 404         ctrl1 = rx8025->ctrl1;
 405         if (enabled)
 406                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
 407         else
 408                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 409
 410         if (ctrl1 != rx8025->ctrl1) {
 411                 rx8025->ctrl1 = ctrl1;
 412                 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
 413                                        rx8025->ctrl1);
 414                 if (err)
 415                         return err;
 416         }
 417         return 0;
 418 }
 419
 420 /*
 421  * According to the RX8025 SA/NB application manual the frequency and
 422  * temperature characteristics can be approximated using the following
 423  * equation:
 424  *
 425  *   df = a * (ut - t)**2
 426  *
 427  *   df: Frequency deviation in any temperature
 428  *   a : Coefficient = (-35 +-5) * 10**-9
 429  *   ut: Ultimate temperature in degree = +25 +-5 degree
 430  *   t : Any temperature in degree
 431  */
 432 static int rx8025_read_offset(struct device *dev, long *offset)
 433 {
 434         struct i2c_client *client = to_i2c_client(dev);
 435         int digoff;
 436
 437         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
 438         if (digoff < 0)
 439                 return digoff;
 440
 441         *offset = digoff >= 64 ? digoff - 128 : digoff;
 442         if (*offset > 0)
 443                 (*offset)--;
 444         *offset *= RX8025_ADJ_RESOLUTION;
 445
 446         return 0;
 447 }
 448
 449 static int rx8025_set_offset(struct device *dev, long offset)
 450 {
 451         struct i2c_client *client = to_i2c_client(dev);
 452         u8 digoff;
 453
 454         offset /= RX8025_ADJ_RESOLUTION;
 455         if (offset > RX8025_ADJ_DATA_MAX)
 456                 offset = RX8025_ADJ_DATA_MAX;
 457         else if (offset < RX8025_ADJ_DATA_MIN)
 458                 offset = RX8025_ADJ_DATA_MIN;
 459         else if (offset > 0)
 460                 offset++;
 461         else if (offset < 0)
 462                 offset += 128;
 463         digoff = offset;
 464
 465         return rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
 466 }
 467
 468 static const struct rtc_class_ops rx8025_rtc_ops = {
 469         .read_time = rx8025_get_time,
 470         .set_time = rx8025_set_time,
 471         .read_alarm = rx8025_read_alarm,
 472         .set_alarm = rx8025_set_alarm,
 473         .alarm_irq_enable = rx8025_alarm_irq_enable,
 474         .read_offset = rx8025_read_offset,
 475         .set_offset = rx8025_set_offset,
 476 };
 477
 478 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
 479                                               struct device_attribute *attr,
 480                                               char *buf)
 481 {
 482         long adj;
 483         int err;
 484
 485         dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
 486         err = rx8025_read_offset(dev, &adj);
 487         if (err)
 488                 return err;
 489
 490         return sprintf(buf, "%ld\n", -adj);
 491 }
 492
 493 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
 494                                                struct device_attribute *attr,
 495                                                const char *buf, size_t count)
 496 {
 497         long adj;
 498         int err;
 499
 500         dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
 501         if (kstrtol(buf, 10, &adj) != 0)
 502                 return -EINVAL;
 503
 504         err = rx8025_set_offset(dev, -adj);
 505
 506         return err ? err : count;
 507 }
 508
 509 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
 510                    rx8025_sysfs_show_clock_adjust,
 511                    rx8025_sysfs_store_clock_adjust);
 512
 513 static struct attribute *rx8025_attrs[] = {
 514         &dev_attr_clock_adjust_ppb.attr,
 515         NULL
 516 };
 517
 518 static const struct attribute_group rx8025_attr_group = {
 519         .attrs  = rx8025_attrs,
 520 };
 521
 522 static int rx8025_probe(struct i2c_client *client,
 523                         const struct i2c_device_id *id)
 524 {
 525         struct i2c_adapter *adapter = client->adapter;
 526         struct rx8025_data *rx8025;
 527         int err = 0;
 528
 529         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 530                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 531                 dev_err(&adapter->dev,
 532                         "doesn't support required functionality\n");
 533                 return -EIO;
 534         }
 535
 536         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 537         if (!rx8025)
 538                 return -ENOMEM;
 539
 540         i2c_set_clientdata(client, rx8025);
 541
 542         if (id)
 543                 rx8025->model = id->driver_data;
 544
 545         err = rx8025_init_client(client);
 546         if (err)
 547                 return err;
 548
 549         rx8025->rtc = devm_rtc_allocate_device(&client->dev);
 550         if (IS_ERR(rx8025->rtc))
 551                 return PTR_ERR(rx8025->rtc);
 552
 553         rx8025->rtc->ops = &rx8025_rtc_ops;
 554         rx8025->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
 555         rx8025->rtc->range_max = RTC_TIMESTAMP_END_2099;
 556
 557         if (client->irq > 0) {
 558                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 559                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 560                                                 rx8025_handle_irq,
 561                                                 IRQF_ONESHOT,
 562                                                 "rx8025", client);
 563                 if (err)
 564                         clear_bit(RTC_FEATURE_ALARM, rx8025->rtc->features);
 565         }
 566
 567         rx8025->rtc->max_user_freq = 1;
 568
 569         set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rx8025->rtc->features);
 570         clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rx8025->rtc->features);
 571
 572         err = rtc_add_group(rx8025->rtc, &rx8025_attr_group);
 573         if (err)
 574                 return err;
 575
 576         return devm_rtc_register_device(rx8025->rtc);
 577 }
 578
 579 static struct i2c_driver rx8025_driver = {
 580         .driver = {
 581                 .name = "rtc-rx8025",
 582         },
 583         .probe          = rx8025_probe,
 584         .id_table       = rx8025_id,
 585 };
 586
 587 module_i2c_driver(rx8025_driver);
 588
 589 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 590 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
 591 MODULE_LICENSE("GPL");