drivers/rtc/rtc-pcf8523.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Avionic Design GmbH
   4  */
   5
   6 #include <linux/bcd.h>
   7 #include <linux/bitfield.h>
   8 #include <linux/i2c.h>
   9 #include <linux/module.h>
  10 #include <linux/regmap.h>
  11 #include <linux/rtc.h>
  12 #include <linux/of.h>
  13 #include <linux/pm_wakeirq.h>
  14
  15 #define PCF8523_REG_CONTROL1 0x00
  16 #define PCF8523_CONTROL1_CAP_SEL BIT(7)
  17 #define PCF8523_CONTROL1_STOP    BIT(5)
  18 #define PCF8523_CONTROL1_AIE    BIT(1)
  19
  20 #define PCF8523_REG_CONTROL2 0x01
  21 #define PCF8523_CONTROL2_AF BIT(3)
  22
  23 #define PCF8523_REG_CONTROL3 0x02
  24 #define PCF8523_CONTROL3_PM  GENMASK(7, 5)
  25 #define PCF8523_PM_STANDBY   0x7
  26 #define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
  27 #define PCF8523_CONTROL3_BSF BIT(3)
  28
  29 #define PCF8523_REG_SECONDS  0x03
  30 #define PCF8523_SECONDS_OS BIT(7)
  31
  32 #define PCF8523_REG_MINUTES  0x04
  33 #define PCF8523_REG_HOURS    0x05
  34 #define PCF8523_REG_DAYS     0x06
  35 #define PCF8523_REG_WEEKDAYS 0x07
  36 #define PCF8523_REG_MONTHS   0x08
  37 #define PCF8523_REG_YEARS    0x09
  38
  39 #define PCF8523_REG_MINUTE_ALARM        0x0a
  40 #define PCF8523_REG_HOUR_ALARM          0x0b
  41 #define PCF8523_REG_DAY_ALARM           0x0c
  42 #define PCF8523_REG_WEEKDAY_ALARM       0x0d
  43 #define ALARM_DIS BIT(7)
  44
  45 #define PCF8523_REG_OFFSET   0x0e
  46 #define PCF8523_OFFSET_MODE BIT(7)
  47
  48 #define PCF8523_TMR_CLKOUT_CTRL 0x0f
  49
  50 struct pcf8523 {
  51         struct rtc_device *rtc;
  52         struct regmap *regmap;
  53 };
  54
  55 static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
  56 {
  57         u32 load, value = 0;
  58
  59         load = 12500;
  60         of_property_read_u32(node, "quartz-load-femtofarads", &load);
  61
  62         switch (load) {
  63         default:
  64                 dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
  65                          load);
  66                 fallthrough;
  67         case 12500:
  68                 value = PCF8523_CONTROL1_CAP_SEL;
  69                 break;
  70         case 7000:
  71                 break;
  72         }
  73
  74         return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
  75                                   PCF8523_CONTROL1_CAP_SEL, value);
  76 }
  77
  78 static irqreturn_t pcf8523_irq(int irq, void *dev_id)
  79 {
  80         struct pcf8523 *pcf8523 = dev_id;
  81         u32 value;
  82         int err;
  83
  84         err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
  85         if (err < 0)
  86                 return IRQ_HANDLED;
  87
  88         if (value & PCF8523_CONTROL2_AF) {
  89                 value &= ~PCF8523_CONTROL2_AF;
  90                 regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value);
  91                 rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);
  92
  93                 return IRQ_HANDLED;
  94         }
  95
  96         return IRQ_NONE;
  97 }
  98
  99 static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
 100 {
 101         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 102         u8 regs[10];
 103         int err;
 104
 105         err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs,
 106                                sizeof(regs));
 107         if (err < 0)
 108                 return err;
 109
 110         if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS))
 111                 return -EINVAL;
 112
 113         tm->tm_sec = bcd2bin(regs[3] & 0x7f);
 114         tm->tm_min = bcd2bin(regs[4] & 0x7f);
 115         tm->tm_hour = bcd2bin(regs[5] & 0x3f);
 116         tm->tm_mday = bcd2bin(regs[6] & 0x3f);
 117         tm->tm_wday = regs[7] & 0x7;
 118         tm->tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
 119         tm->tm_year = bcd2bin(regs[9]) + 100;
 120
 121         return 0;
 122 }
 123
 124 static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
 125 {
 126         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 127         u8 regs[7];
 128         int err;
 129
 130         err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
 131                                  PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
 132         if (err < 0)
 133                 return err;
 134
 135         /* This will purposely overwrite PCF8523_SECONDS_OS */
 136         regs[0] = bin2bcd(tm->tm_sec);
 137         regs[1] = bin2bcd(tm->tm_min);
 138         regs[2] = bin2bcd(tm->tm_hour);
 139         regs[3] = bin2bcd(tm->tm_mday);
 140         regs[4] = tm->tm_wday;
 141         regs[5] = bin2bcd(tm->tm_mon + 1);
 142         regs[6] = bin2bcd(tm->tm_year - 100);
 143
 144         err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
 145                                 sizeof(regs));
 146         if (err < 0) {
 147                 /*
 148                  * If the time cannot be set, restart the RTC anyway. Note
 149                  * that errors are ignored if the RTC cannot be started so
 150                  * that we have a chance to propagate the original error.
 151                  */
 152                 regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
 153                                    PCF8523_CONTROL1_STOP, 0);
 154                 return err;
 155         }
 156
 157         return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
 158                                  PCF8523_CONTROL1_STOP, 0);
 159 }
 160
 161 static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
 162 {
 163         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 164         u8 regs[4];
 165         u32 value;
 166         int err;
 167
 168         err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
 169                                sizeof(regs));
 170         if (err < 0)
 171                 return err;
 172
 173         tm->time.tm_sec = 0;
 174         tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
 175         tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
 176         tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
 177         tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
 178
 179         err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
 180         if (err < 0)
 181                 return err;
 182         tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
 183
 184         err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
 185         if (err < 0)
 186                 return err;
 187         tm->pending = !!(value & PCF8523_CONTROL2_AF);
 188
 189         return 0;
 190 }
 191
 192 static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
 193 {
 194         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 195
 196         return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
 197                                   PCF8523_CONTROL1_AIE, enabled ?
 198                                   PCF8523_CONTROL1_AIE : 0);
 199 }
 200
 201 static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 202 {
 203         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 204         u8 regs[5];
 205         int err;
 206
 207         err = pcf8523_irq_enable(dev, 0);
 208         if (err)
 209                 return err;
 210
 211         err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
 212         if (err < 0)
 213                 return err;
 214
 215         regs[0] = bin2bcd(tm->time.tm_min);
 216         regs[1] = bin2bcd(tm->time.tm_hour);
 217         regs[2] = bin2bcd(tm->time.tm_mday);
 218         regs[3] = ALARM_DIS;
 219
 220         err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
 221                                 sizeof(regs));
 222         if (err < 0)
 223                 return err;
 224
 225         if (tm->enabled)
 226                 return pcf8523_irq_enable(dev, tm->enabled);
 227
 228         return 0;
 229 }
 230
 231 static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
 232 {
 233         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 234         int ret;
 235         u32 value;
 236
 237         switch (param->param) {
 238         case RTC_PARAM_BACKUP_SWITCH_MODE:
 239                 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
 240                 if (ret < 0)
 241                         return ret;
 242
 243                 value = FIELD_GET(PCF8523_CONTROL3_PM, value);
 244
 245                 switch (value) {
 246                 case 0x0:
 247                 case 0x4:
 248                         param->uvalue = RTC_BSM_LEVEL;
 249                         break;
 250                 case 0x1:
 251                 case 0x5:
 252                         param->uvalue = RTC_BSM_DIRECT;
 253                         break;
 254                 case PCF8523_PM_STANDBY:
 255                         param->uvalue = RTC_BSM_STANDBY;
 256                         break;
 257                 default:
 258                         param->uvalue = RTC_BSM_DISABLED;
 259                 }
 260
 261                 break;
 262
 263         default:
 264                 return -EINVAL;
 265         }
 266
 267         return 0;
 268 }
 269
 270 static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
 271 {
 272         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 273         u8 mode;
 274
 275         switch (param->param) {
 276         case RTC_PARAM_BACKUP_SWITCH_MODE:
 277                 switch (param->uvalue) {
 278                 case RTC_BSM_DISABLED:
 279                         mode = 0x2;
 280                         break;
 281                 case RTC_BSM_DIRECT:
 282                         mode = 0x1;
 283                         break;
 284                 case RTC_BSM_LEVEL:
 285                         mode = 0x0;
 286                         break;
 287                 case RTC_BSM_STANDBY:
 288                         mode = PCF8523_PM_STANDBY;
 289                         break;
 290                 default:
 291                         return -EINVAL;
 292                 }
 293
 294                 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
 295                                           PCF8523_CONTROL3_PM,
 296                                           FIELD_PREP(PCF8523_CONTROL3_PM, mode));
 297
 298                 break;
 299
 300         default:
 301                 return -EINVAL;
 302         }
 303
 304         return 0;
 305 }
 306
 307 static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 308                              unsigned long arg)
 309 {
 310         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 311         unsigned int flags = 0;
 312         u32 value;
 313         int ret;
 314
 315         switch (cmd) {
 316         case RTC_VL_READ:
 317                 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
 318                 if (ret < 0)
 319                         return ret;
 320
 321                 if (value & PCF8523_CONTROL3_BLF)
 322                         flags |= RTC_VL_BACKUP_LOW;
 323
 324                 ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
 325                 if (ret < 0)
 326                         return ret;
 327
 328                 if (value & PCF8523_SECONDS_OS)
 329                         flags |= RTC_VL_DATA_INVALID;
 330
 331                 return put_user(flags, (unsigned int __user *)arg);
 332
 333         default:
 334                 return -ENOIOCTLCMD;
 335         }
 336 }
 337
 338 static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
 339 {
 340         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 341         int err;
 342         u32 value;
 343         s8 val;
 344
 345         err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
 346         if (err < 0)
 347                 return err;
 348
 349         /* sign extend the 7-bit offset value */
 350         val = value << 1;
 351         *offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
 352
 353         return 0;
 354 }
 355
 356 static int pcf8523_rtc_set_offset(struct device *dev, long offset)
 357 {
 358         struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
 359         long reg_m0, reg_m1;
 360         u32 value;
 361
 362         reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
 363         reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
 364
 365         if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
 366                 value = reg_m0 & 0x7f;
 367         else
 368                 value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
 369
 370         return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
 371 }
 372
 373 static const struct rtc_class_ops pcf8523_rtc_ops = {
 374         .read_time = pcf8523_rtc_read_time,
 375         .set_time = pcf8523_rtc_set_time,
 376         .read_alarm = pcf8523_rtc_read_alarm,
 377         .set_alarm = pcf8523_rtc_set_alarm,
 378         .alarm_irq_enable = pcf8523_irq_enable,
 379         .ioctl = pcf8523_rtc_ioctl,
 380         .read_offset = pcf8523_rtc_read_offset,
 381         .set_offset = pcf8523_rtc_set_offset,
 382         .param_get = pcf8523_param_get,
 383         .param_set = pcf8523_param_set,
 384 };
 385
 386 static const struct regmap_config regmap_config = {
 387         .reg_bits = 8,
 388         .val_bits = 8,
 389         .max_register = 0x13,
 390 };
 391
 392 static int pcf8523_probe(struct i2c_client *client)
 393 {
 394         struct pcf8523 *pcf8523;
 395         struct rtc_device *rtc;
 396         bool wakeup_source = false;
 397         u32 value;
 398         int err;
 399
 400         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 401                 return -ENODEV;
 402
 403         pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
 404         if (!pcf8523)
 405                 return -ENOMEM;
 406
 407         pcf8523->regmap = devm_regmap_init_i2c(client, &regmap_config);
 408         if (IS_ERR(pcf8523->regmap))
 409                 return PTR_ERR(pcf8523->regmap);
 410
 411         i2c_set_clientdata(client, pcf8523);
 412
 413         rtc = devm_rtc_allocate_device(&client->dev);
 414         if (IS_ERR(rtc))
 415                 return PTR_ERR(rtc);
 416         pcf8523->rtc = rtc;
 417
 418         err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
 419         if (err < 0)
 420                 dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
 421                          err);
 422
 423         err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
 424         if (err < 0)
 425                 return err;
 426
 427         if (value & PCF8523_SECONDS_OS) {
 428                 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
 429                 if (err < 0)
 430                         return err;
 431
 432                 if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
 433                         err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
 434                                            value & ~PCF8523_CONTROL3_PM);
 435                         if (err < 0)
 436                                 return err;
 437                 }
 438         }
 439
 440         rtc->ops = &pcf8523_rtc_ops;
 441         rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 442         rtc->range_max = RTC_TIMESTAMP_END_2099;
 443         set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
 444         clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
 445
 446         if (client->irq > 0) {
 447                 unsigned long irqflags = IRQF_TRIGGER_LOW;
 448
 449                 if (dev_fwnode(&client->dev))
 450                         irqflags = 0;
 451
 452                 err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
 453                 if (err < 0)
 454                         return err;
 455
 456                 err = devm_request_threaded_irq(&client->dev, client->irq,
 457                                                 NULL, pcf8523_irq,
 458                                                 IRQF_SHARED | IRQF_ONESHOT | irqflags,
 459                                                 dev_name(&rtc->dev), pcf8523);
 460                 if (err)
 461                         return err;
 462
 463                 dev_pm_set_wake_irq(&client->dev, client->irq);
 464         }
 465
 466         wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
 467         if (client->irq > 0 || wakeup_source)
 468                 device_init_wakeup(&client->dev, true);
 469
 470         return devm_rtc_register_device(rtc);
 471 }
 472
 473 static const struct i2c_device_id pcf8523_id[] = {
 474         { "pcf8523", 0 },
 475         { }
 476 };
 477 MODULE_DEVICE_TABLE(i2c, pcf8523_id);
 478
 479 static const struct of_device_id pcf8523_of_match[] = {
 480         { .compatible = "nxp,pcf8523" },
 481         { .compatible = "microcrystal,rv8523" },
 482         { }
 483 };
 484 MODULE_DEVICE_TABLE(of, pcf8523_of_match);
 485
 486 static struct i2c_driver pcf8523_driver = {
 487         .driver = {
 488                 .name = "rtc-pcf8523",
 489                 .of_match_table = pcf8523_of_match,
 490         },
 491         .probe = pcf8523_probe,
 492         .id_table = pcf8523_id,
 493 };
 494 module_i2c_driver(pcf8523_driver);
 495
 496 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
 497 MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
 498 MODULE_LICENSE("GPL v2");