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 /* Clock precision adjustment */
  59 #define RX8025_ADJ_RESOLUTION   3050 /* in ppb */
  60 #define RX8025_ADJ_DATA_MAX     62
  61 #define RX8025_ADJ_DATA_MIN     -62
  62
  63 enum rx_model {
  64         model_rx_unknown,
  65         model_rx_8025,
  66         model_rx_8035,
  67         model_last
  68 };
  69
  70 static const struct i2c_device_id rx8025_id[] = {
  71         { "rx8025", model_rx_8025 },
  72         { "rx8035", model_rx_8035 },
  73         { }
  74 };
  75 MODULE_DEVICE_TABLE(i2c, rx8025_id);
  76
  77 struct rx8025_data {
  78         struct rtc_device *rtc;
  79         enum rx_model model;
  80         u8 ctrl1;
  81 };
  82
  83 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
  84 {
  85         return i2c_smbus_read_byte_data(client, number << 4);
  86 }
  87
  88 static int rx8025_read_regs(const struct i2c_client *client,
  89                             u8 number, u8 length, u8 *values)
  90 {
  91         int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
  92                                                 values);
  93         if (ret != length)
  94                 return ret < 0 ? ret : -EIO;
  95
  96         return 0;
  97 }
  98
  99 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
 100                             u8 value)
 101 {
 102         return i2c_smbus_write_byte_data(client, number << 4, value);
 103 }
 104
 105 static s32 rx8025_write_regs(const struct i2c_client *client,
 106                              u8 number, u8 length, const u8 *values)
 107 {
 108         return i2c_smbus_write_i2c_block_data(client, number << 4,
 109                                               length, values);
 110 }
 111
 112 static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
 113 {
 114         int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
 115         /* XSTP bit has different polarity on RX-8025 vs RX-8035.
 116          * RX-8025: 0 == oscillator stopped
 117          * RX-8035: 1 == oscillator stopped
 118          */
 119
 120         if (model == model_rx_8025)
 121                 xstp = !xstp;
 122
 123         return xstp;
 124 }
 125
 126 static int rx8025_check_validity(struct device *dev)
 127 {
 128         struct i2c_client *client = to_i2c_client(dev);
 129         struct rx8025_data *drvdata = dev_get_drvdata(dev);
 130         int ctrl2;
 131         int xstp;
 132
 133         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 134         if (ctrl2 < 0)
 135                 return ctrl2;
 136
 137         if (ctrl2 & RX8025_BIT_CTRL2_VDET)
 138                 dev_warn(dev, "power voltage drop detected\n");
 139
 140         if (ctrl2 & RX8025_BIT_CTRL2_PON) {
 141                 dev_warn(dev, "power-on reset detected, date is invalid\n");
 142                 return -EINVAL;
 143         }
 144
 145         xstp = rx8025_is_osc_stopped(drvdata->model, ctrl2);
 146         if (xstp) {
 147                 dev_warn(dev, "crystal stopped, date is invalid\n");
 148                 return -EINVAL;
 149         }
 150
 151         return 0;
 152 }
 153
 154 static int rx8025_reset_validity(struct i2c_client *client)
 155 {
 156         struct rx8025_data *drvdata = i2c_get_clientdata(client);
 157         int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 158
 159         if (ctrl2 < 0)
 160                 return ctrl2;
 161
 162         ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
 163
 164         if (drvdata->model == model_rx_8025)
 165                 ctrl2 |= RX8025_BIT_CTRL2_XST;
 166         else
 167                 ctrl2 &= ~(RX8025_BIT_CTRL2_XST);
 168
 169         return rx8025_write_reg(client, RX8025_REG_CTRL2,
 170                                 ctrl2);
 171 }
 172
 173 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
 174 {
 175         struct i2c_client *client = dev_id;
 176         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 177         int status, xstp;
 178
 179         rtc_lock(rx8025->rtc);
 180         status = rx8025_read_reg(client, RX8025_REG_CTRL2);
 181         if (status < 0)
 182                 goto out;
 183
 184         xstp = rx8025_is_osc_stopped(rx8025->model, status);
 185         if (xstp)
 186                 dev_warn(&client->dev, "Oscillation stop was detected,"
 187                          "you may have to readjust the clock\n");
 188
 189         if (status & RX8025_BIT_CTRL2_CTFG) {
 190                 /* periodic */
 191                 status &= ~RX8025_BIT_CTRL2_CTFG;
 192                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
 193         }
 194
 195         if (status & RX8025_BIT_CTRL2_DAFG) {
 196                 /* alarm */
 197                 status &= RX8025_BIT_CTRL2_DAFG;
 198                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
 199                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
 200                         goto out;
 201                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
 202         }
 203
 204 out:
 205         rtc_unlock(rx8025->rtc);
 206
 207         return IRQ_HANDLED;
 208 }
 209
 210 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
 211 {
 212         struct i2c_client *client = to_i2c_client(dev);
 213         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 214         u8 date[7];
 215         int err;
 216
 217         err = rx8025_check_validity(dev);
 218         if (err)
 219                 return err;
 220
 221         err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
 222         if (err)
 223                 return err;
 224
 225         dev_dbg(dev, "%s: read %7ph\n", __func__, date);
 226
 227         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
 228         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
 229         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 230                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
 231         else
 232                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
 233                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
 234
 235         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
 236         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
 237         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
 238
 239         dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
 240
 241         return 0;
 242 }
 243
 244 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
 245 {
 246         struct i2c_client *client = to_i2c_client(dev);
 247         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 248         u8 date[7];
 249         int ret;
 250
 251         /*
 252          * Here the read-only bits are written as "0".  I'm not sure if that
 253          * is sound.
 254          */
 255         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
 256         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
 257         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 258                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
 259         else
 260                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
 261                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
 262
 263         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
 264         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
 265         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
 266         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
 267
 268         dev_dbg(dev, "%s: write %7ph\n", __func__, date);
 269
 270         ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
 271         if (ret < 0)
 272                 return ret;
 273
 274         return rx8025_reset_validity(client);
 275 }
 276
 277 static int rx8025_init_client(struct i2c_client *client)
 278 {
 279         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
 280         u8 ctrl[2], ctrl2;
 281         int need_clear = 0;
 282         int err;
 283
 284         err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
 285         if (err)
 286                 goto out;
 287
 288         /* Keep test bit zero ! */
 289         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
 290
 291         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
 292                 dev_warn(&client->dev, "Alarm was detected\n");
 293                 need_clear = 1;
 294         }
 295
 296         if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
 297                 need_clear = 1;
 298
 299         if (need_clear) {
 300                 ctrl2 = ctrl[1];
 301                 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
 302                            RX8025_BIT_CTRL2_DAFG);
 303
 304                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
 305         }
 306 out:
 307         return err;
 308 }
 309
 310 /* Alarm support */
 311 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 312 {
 313         struct i2c_client *client = to_i2c_client(dev);
 314         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 315         u8 ald[2];
 316         int ctrl2, err;
 317
 318         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
 319         if (err)
 320                 return err;
 321
 322         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
 323         if (ctrl2 < 0)
 324                 return ctrl2;
 325
 326         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
 327                 __func__, ald[0], ald[1], ctrl2);
 328
 329         /* Hardware alarms precision is 1 minute! */
 330         t->time.tm_sec = 0;
 331         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 332         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 333                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
 334         else
 335                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
 336                         + (ald[1] & 0x20 ? 12 : 0);
 337
 338         dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
 339         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
 340         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
 341
 342         return err;
 343 }
 344
 345 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 346 {
 347         struct i2c_client *client = to_i2c_client(dev);
 348         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
 349         u8 ald[2];
 350         int err;
 351
 352         ald[0] = bin2bcd(t->time.tm_min);
 353         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
 354                 ald[1] = bin2bcd(t->time.tm_hour);
 355         else
 356                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
 357                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
 358
 359         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
 360
 361         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
 362                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
 363                 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
 364                                        rx8025->ctrl1);
 365                 if (err)
 366                         return err;
 367         }
 368         err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
 369         if (err)
 370                 return err;
 371
 372         if (t->enabled) {
 373                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
 374                 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
 375                                        rx8025->ctrl1);
 376                 if (err)
 377                         return err;
 378         }
 379
 380         return 0;
 381 }
 382
 383 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
 384 {
 385         struct i2c_client *client = to_i2c_client(dev);
 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(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 struct attribute *rx8025_attrs[] = {
 506         &dev_attr_clock_adjust_ppb.attr,
 507         NULL
 508 };
 509
 510 static const struct attribute_group rx8025_attr_group = {
 511         .attrs  = rx8025_attrs,
 512 };
 513
 514 static int rx8025_probe(struct i2c_client *client,
 515                         const struct i2c_device_id *id)
 516 {
 517         struct i2c_adapter *adapter = client->adapter;
 518         struct rx8025_data *rx8025;
 519         int err = 0;
 520
 521         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 522                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 523                 dev_err(&adapter->dev,
 524                         "doesn't support required functionality\n");
 525                 return -EIO;
 526         }
 527
 528         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
 529         if (!rx8025)
 530                 return -ENOMEM;
 531
 532         i2c_set_clientdata(client, rx8025);
 533
 534         if (id)
 535                 rx8025->model = id->driver_data;
 536
 537         err = rx8025_init_client(client);
 538         if (err)
 539                 return err;
 540
 541         rx8025->rtc = devm_rtc_allocate_device(&client->dev);
 542         if (IS_ERR(rx8025->rtc))
 543                 return PTR_ERR(rx8025->rtc);
 544
 545         rx8025->rtc->ops = &rx8025_rtc_ops;
 546         rx8025->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
 547         rx8025->rtc->range_max = RTC_TIMESTAMP_END_2099;
 548
 549         if (client->irq > 0) {
 550                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
 551                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 552                                                 rx8025_handle_irq,
 553                                                 IRQF_ONESHOT,
 554                                                 "rx8025", client);
 555                 if (err)
 556                         clear_bit(RTC_FEATURE_ALARM, rx8025->rtc->features);
 557         }
 558
 559         rx8025->rtc->max_user_freq = 1;
 560
 561         set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rx8025->rtc->features);
 562         clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rx8025->rtc->features);
 563
 564         err = rtc_add_group(rx8025->rtc, &rx8025_attr_group);
 565         if (err)
 566                 return err;
 567
 568         return devm_rtc_register_device(rx8025->rtc);
 569 }
 570
 571 static struct i2c_driver rx8025_driver = {
 572         .driver = {
 573                 .name = "rtc-rx8025",
 574         },
 575         .probe          = rx8025_probe,
 576         .id_table       = rx8025_id,
 577 };
 578
 579 module_i2c_driver(rx8025_driver);
 580
 581 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 582 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
 583 MODULE_LICENSE("GPL");