drivers/rtc/rtc-pcf85363.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * drivers/rtc/rtc-pcf85363.c
   4  *
   5  * Driver for NXP PCF85363 real-time clock.
   6  *
   7  * Copyright (C) 2017 Eric Nelson
   8  */
   9 #include <linux/module.h>
  10 #include <linux/i2c.h>
  11 #include <linux/slab.h>
  12 #include <linux/rtc.h>
  13 #include <linux/init.h>
  14 #include <linux/err.h>
  15 #include <linux/errno.h>
  16 #include <linux/bcd.h>
  17 #include <linux/of.h>
  18 #include <linux/regmap.h>
  19
  20 /*
  21  * Date/Time registers
  22  */
  23 #define DT_100THS       0x00
  24 #define DT_SECS         0x01
  25 #define DT_MINUTES      0x02
  26 #define DT_HOURS        0x03
  27 #define DT_DAYS         0x04
  28 #define DT_WEEKDAYS     0x05
  29 #define DT_MONTHS       0x06
  30 #define DT_YEARS        0x07
  31
  32 /*
  33  * Alarm registers
  34  */
  35 #define DT_SECOND_ALM1  0x08
  36 #define DT_MINUTE_ALM1  0x09
  37 #define DT_HOUR_ALM1    0x0a
  38 #define DT_DAY_ALM1     0x0b
  39 #define DT_MONTH_ALM1   0x0c
  40 #define DT_MINUTE_ALM2  0x0d
  41 #define DT_HOUR_ALM2    0x0e
  42 #define DT_WEEKDAY_ALM2 0x0f
  43 #define DT_ALARM_EN     0x10
  44
  45 /*
  46  * Time stamp registers
  47  */
  48 #define DT_TIMESTAMP1   0x11
  49 #define DT_TIMESTAMP2   0x17
  50 #define DT_TIMESTAMP3   0x1d
  51 #define DT_TS_MODE      0x23
  52
  53 /*
  54  * control registers
  55  */
  56 #define CTRL_OFFSET     0x24
  57 #define CTRL_OSCILLATOR 0x25
  58 #define CTRL_BATTERY    0x26
  59 #define CTRL_PIN_IO     0x27
  60 #define CTRL_FUNCTION   0x28
  61 #define CTRL_INTA_EN    0x29
  62 #define CTRL_INTB_EN    0x2a
  63 #define CTRL_FLAGS      0x2b
  64 #define CTRL_RAMBYTE    0x2c
  65 #define CTRL_WDOG       0x2d
  66 #define CTRL_STOP_EN    0x2e
  67 #define CTRL_RESETS     0x2f
  68 #define CTRL_RAM        0x40
  69
  70 #define ALRM_SEC_A1E    BIT(0)
  71 #define ALRM_MIN_A1E    BIT(1)
  72 #define ALRM_HR_A1E     BIT(2)
  73 #define ALRM_DAY_A1E    BIT(3)
  74 #define ALRM_MON_A1E    BIT(4)
  75 #define ALRM_MIN_A2E    BIT(5)
  76 #define ALRM_HR_A2E     BIT(6)
  77 #define ALRM_DAY_A2E    BIT(7)
  78
  79 #define INT_WDIE        BIT(0)
  80 #define INT_BSIE        BIT(1)
  81 #define INT_TSRIE       BIT(2)
  82 #define INT_A2IE        BIT(3)
  83 #define INT_A1IE        BIT(4)
  84 #define INT_OIE         BIT(5)
  85 #define INT_PIE         BIT(6)
  86 #define INT_ILP         BIT(7)
  87
  88 #define FLAGS_TSR1F     BIT(0)
  89 #define FLAGS_TSR2F     BIT(1)
  90 #define FLAGS_TSR3F     BIT(2)
  91 #define FLAGS_BSF       BIT(3)
  92 #define FLAGS_WDF       BIT(4)
  93 #define FLAGS_A1F       BIT(5)
  94 #define FLAGS_A2F       BIT(6)
  95 #define FLAGS_PIF       BIT(7)
  96
  97 #define PIN_IO_INTAPM   GENMASK(1, 0)
  98 #define PIN_IO_INTA_CLK 0
  99 #define PIN_IO_INTA_BAT 1
 100 #define PIN_IO_INTA_OUT 2
 101 #define PIN_IO_INTA_HIZ 3
 102
 103 #define OSC_CAP_SEL     GENMASK(1, 0)
 104 #define OSC_CAP_6000    0x01
 105 #define OSC_CAP_12500   0x02
 106
 107 #define STOP_EN_STOP    BIT(0)
 108
 109 #define RESET_CPR       0xa4
 110
 111 #define NVRAM_SIZE      0x40
 112
 113 struct pcf85363 {
 114         struct rtc_device       *rtc;
 115         struct regmap           *regmap;
 116 };
 117
 118 struct pcf85x63_config {
 119         struct regmap_config regmap;
 120         unsigned int num_nvram;
 121 };
 122
 123 static int pcf85363_load_capacitance(struct pcf85363 *pcf85363, struct device_node *node)
 124 {
 125         u32 load = 7000;
 126         u8 value = 0;
 127
 128         of_property_read_u32(node, "quartz-load-femtofarads", &load);
 129
 130         switch (load) {
 131         default:
 132                 dev_warn(&pcf85363->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 7000",
 133                          load);
 134                 fallthrough;
 135         case 7000:
 136                 break;
 137         case 6000:
 138                 value = OSC_CAP_6000;
 139                 break;
 140         case 12500:
 141                 value = OSC_CAP_12500;
 142                 break;
 143         }
 144
 145         return regmap_update_bits(pcf85363->regmap, CTRL_OSCILLATOR,
 146                                   OSC_CAP_SEL, value);
 147 }
 148
 149 static int pcf85363_rtc_read_time(struct device *dev, struct rtc_time *tm)
 150 {
 151         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 152         unsigned char buf[DT_YEARS + 1];
 153         int ret, len = sizeof(buf);
 154
 155         /* read the RTC date and time registers all at once */
 156         ret = regmap_bulk_read(pcf85363->regmap, DT_100THS, buf, len);
 157         if (ret) {
 158                 dev_err(dev, "%s: error %d\n", __func__, ret);
 159                 return ret;
 160         }
 161
 162         tm->tm_year = bcd2bin(buf[DT_YEARS]);
 163         /* adjust for 1900 base of rtc_time */
 164         tm->tm_year += 100;
 165
 166         tm->tm_wday = buf[DT_WEEKDAYS] & 7;
 167         buf[DT_SECS] &= 0x7F;
 168         tm->tm_sec = bcd2bin(buf[DT_SECS]);
 169         buf[DT_MINUTES] &= 0x7F;
 170         tm->tm_min = bcd2bin(buf[DT_MINUTES]);
 171         tm->tm_hour = bcd2bin(buf[DT_HOURS]);
 172         tm->tm_mday = bcd2bin(buf[DT_DAYS]);
 173         tm->tm_mon = bcd2bin(buf[DT_MONTHS]) - 1;
 174
 175         return 0;
 176 }
 177
 178 static int pcf85363_rtc_set_time(struct device *dev, struct rtc_time *tm)
 179 {
 180         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 181         unsigned char tmp[11];
 182         unsigned char *buf = &tmp[2];
 183         int ret;
 184
 185         tmp[0] = STOP_EN_STOP;
 186         tmp[1] = RESET_CPR;
 187
 188         buf[DT_100THS] = 0;
 189         buf[DT_SECS] = bin2bcd(tm->tm_sec);
 190         buf[DT_MINUTES] = bin2bcd(tm->tm_min);
 191         buf[DT_HOURS] = bin2bcd(tm->tm_hour);
 192         buf[DT_DAYS] = bin2bcd(tm->tm_mday);
 193         buf[DT_WEEKDAYS] = tm->tm_wday;
 194         buf[DT_MONTHS] = bin2bcd(tm->tm_mon + 1);
 195         buf[DT_YEARS] = bin2bcd(tm->tm_year % 100);
 196
 197         ret = regmap_bulk_write(pcf85363->regmap, CTRL_STOP_EN,
 198                                 tmp, 2);
 199         if (ret)
 200                 return ret;
 201
 202         ret = regmap_bulk_write(pcf85363->regmap, DT_100THS,
 203                                 buf, sizeof(tmp) - 2);
 204         if (ret)
 205                 return ret;
 206
 207         return regmap_write(pcf85363->regmap, CTRL_STOP_EN, 0);
 208 }
 209
 210 static int pcf85363_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 211 {
 212         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 213         unsigned char buf[DT_MONTH_ALM1 - DT_SECOND_ALM1 + 1];
 214         unsigned int val;
 215         int ret;
 216
 217         ret = regmap_bulk_read(pcf85363->regmap, DT_SECOND_ALM1, buf,
 218                                sizeof(buf));
 219         if (ret)
 220                 return ret;
 221
 222         alrm->time.tm_sec = bcd2bin(buf[0]);
 223         alrm->time.tm_min = bcd2bin(buf[1]);
 224         alrm->time.tm_hour = bcd2bin(buf[2]);
 225         alrm->time.tm_mday = bcd2bin(buf[3]);
 226         alrm->time.tm_mon = bcd2bin(buf[4]) - 1;
 227
 228         ret = regmap_read(pcf85363->regmap, CTRL_INTA_EN, &val);
 229         if (ret)
 230                 return ret;
 231
 232         alrm->enabled =  !!(val & INT_A1IE);
 233
 234         return 0;
 235 }
 236
 237 static int _pcf85363_rtc_alarm_irq_enable(struct pcf85363 *pcf85363, unsigned
 238                                           int enabled)
 239 {
 240         unsigned int alarm_flags = ALRM_SEC_A1E | ALRM_MIN_A1E | ALRM_HR_A1E |
 241                                    ALRM_DAY_A1E | ALRM_MON_A1E;
 242         int ret;
 243
 244         ret = regmap_update_bits(pcf85363->regmap, DT_ALARM_EN, alarm_flags,
 245                                  enabled ? alarm_flags : 0);
 246         if (ret)
 247                 return ret;
 248
 249         ret = regmap_update_bits(pcf85363->regmap, CTRL_INTA_EN,
 250                                  INT_A1IE, enabled ? INT_A1IE : 0);
 251
 252         if (ret || enabled)
 253                 return ret;
 254
 255         /* clear current flags */
 256         return regmap_update_bits(pcf85363->regmap, CTRL_FLAGS, FLAGS_A1F, 0);
 257 }
 258
 259 static int pcf85363_rtc_alarm_irq_enable(struct device *dev,
 260                                          unsigned int enabled)
 261 {
 262         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 263
 264         return _pcf85363_rtc_alarm_irq_enable(pcf85363, enabled);
 265 }
 266
 267 static int pcf85363_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 268 {
 269         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 270         unsigned char buf[DT_MONTH_ALM1 - DT_SECOND_ALM1 + 1];
 271         int ret;
 272
 273         buf[0] = bin2bcd(alrm->time.tm_sec);
 274         buf[1] = bin2bcd(alrm->time.tm_min);
 275         buf[2] = bin2bcd(alrm->time.tm_hour);
 276         buf[3] = bin2bcd(alrm->time.tm_mday);
 277         buf[4] = bin2bcd(alrm->time.tm_mon + 1);
 278
 279         /*
 280          * Disable the alarm interrupt before changing the value to avoid
 281          * spurious interrupts
 282          */
 283         ret = _pcf85363_rtc_alarm_irq_enable(pcf85363, 0);
 284         if (ret)
 285                 return ret;
 286
 287         ret = regmap_bulk_write(pcf85363->regmap, DT_SECOND_ALM1, buf,
 288                                 sizeof(buf));
 289         if (ret)
 290                 return ret;
 291
 292         return _pcf85363_rtc_alarm_irq_enable(pcf85363, alrm->enabled);
 293 }
 294
 295 static irqreturn_t pcf85363_rtc_handle_irq(int irq, void *dev_id)
 296 {
 297         struct pcf85363 *pcf85363 = i2c_get_clientdata(dev_id);
 298         unsigned int flags;
 299         int err;
 300
 301         err = regmap_read(pcf85363->regmap, CTRL_FLAGS, &flags);
 302         if (err)
 303                 return IRQ_NONE;
 304
 305         if (flags & FLAGS_A1F) {
 306                 rtc_update_irq(pcf85363->rtc, 1, RTC_IRQF | RTC_AF);
 307                 regmap_update_bits(pcf85363->regmap, CTRL_FLAGS, FLAGS_A1F, 0);
 308                 return IRQ_HANDLED;
 309         }
 310
 311         return IRQ_NONE;
 312 }
 313
 314 static const struct rtc_class_ops rtc_ops = {
 315         .read_time      = pcf85363_rtc_read_time,
 316         .set_time       = pcf85363_rtc_set_time,
 317         .read_alarm     = pcf85363_rtc_read_alarm,
 318         .set_alarm      = pcf85363_rtc_set_alarm,
 319         .alarm_irq_enable = pcf85363_rtc_alarm_irq_enable,
 320 };
 321
 322 static int pcf85363_nvram_read(void *priv, unsigned int offset, void *val,
 323                                size_t bytes)
 324 {
 325         struct pcf85363 *pcf85363 = priv;
 326
 327         return regmap_bulk_read(pcf85363->regmap, CTRL_RAM + offset,
 328                                 val, bytes);
 329 }
 330
 331 static int pcf85363_nvram_write(void *priv, unsigned int offset, void *val,
 332                                 size_t bytes)
 333 {
 334         struct pcf85363 *pcf85363 = priv;
 335
 336         return regmap_bulk_write(pcf85363->regmap, CTRL_RAM + offset,
 337                                  val, bytes);
 338 }
 339
 340 static int pcf85x63_nvram_read(void *priv, unsigned int offset, void *val,
 341                                size_t bytes)
 342 {
 343         struct pcf85363 *pcf85363 = priv;
 344         unsigned int tmp_val;
 345         int ret;
 346
 347         ret = regmap_read(pcf85363->regmap, CTRL_RAMBYTE, &tmp_val);
 348         (*(unsigned char *) val) = (unsigned char) tmp_val;
 349
 350         return ret;
 351 }
 352
 353 static int pcf85x63_nvram_write(void *priv, unsigned int offset, void *val,
 354                                 size_t bytes)
 355 {
 356         struct pcf85363 *pcf85363 = priv;
 357         unsigned char tmp_val;
 358
 359         tmp_val = *((unsigned char *)val);
 360         return regmap_write(pcf85363->regmap, CTRL_RAMBYTE,
 361                                 (unsigned int)tmp_val);
 362 }
 363
 364 static const struct pcf85x63_config pcf_85263_config = {
 365         .regmap = {
 366                 .reg_bits = 8,
 367                 .val_bits = 8,
 368                 .max_register = 0x2f,
 369         },
 370         .num_nvram = 1
 371 };
 372
 373 static const struct pcf85x63_config pcf_85363_config = {
 374         .regmap = {
 375                 .reg_bits = 8,
 376                 .val_bits = 8,
 377                 .max_register = 0x7f,
 378         },
 379         .num_nvram = 2
 380 };
 381
 382 static int pcf85363_probe(struct i2c_client *client)
 383 {
 384         struct pcf85363 *pcf85363;
 385         const struct pcf85x63_config *config = &pcf_85363_config;
 386         const void *data = of_device_get_match_data(&client->dev);
 387         static struct nvmem_config nvmem_cfg[] = {
 388                 {
 389                         .name = "pcf85x63-",
 390                         .word_size = 1,
 391                         .stride = 1,
 392                         .size = 1,
 393                         .reg_read = pcf85x63_nvram_read,
 394                         .reg_write = pcf85x63_nvram_write,
 395                 }, {
 396                         .name = "pcf85363-",
 397                         .word_size = 1,
 398                         .stride = 1,
 399                         .size = NVRAM_SIZE,
 400                         .reg_read = pcf85363_nvram_read,
 401                         .reg_write = pcf85363_nvram_write,
 402                 },
 403         };
 404         int ret, i, err;
 405         bool wakeup_source;
 406
 407         if (data)
 408                 config = data;
 409
 410         pcf85363 = devm_kzalloc(&client->dev, sizeof(struct pcf85363),
 411                                 GFP_KERNEL);
 412         if (!pcf85363)
 413                 return -ENOMEM;
 414
 415         pcf85363->regmap = devm_regmap_init_i2c(client, &config->regmap);
 416         if (IS_ERR(pcf85363->regmap)) {
 417                 dev_err(&client->dev, "regmap allocation failed\n");
 418                 return PTR_ERR(pcf85363->regmap);
 419         }
 420
 421         i2c_set_clientdata(client, pcf85363);
 422
 423         pcf85363->rtc = devm_rtc_allocate_device(&client->dev);
 424         if (IS_ERR(pcf85363->rtc))
 425                 return PTR_ERR(pcf85363->rtc);
 426
 427         err = pcf85363_load_capacitance(pcf85363, client->dev.of_node);
 428         if (err < 0)
 429                 dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
 430                          err);
 431
 432         pcf85363->rtc->ops = &rtc_ops;
 433         pcf85363->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 434         pcf85363->rtc->range_max = RTC_TIMESTAMP_END_2099;
 435
 436         wakeup_source = device_property_read_bool(&client->dev,
 437                                                   "wakeup-source");
 438         if (client->irq > 0 || wakeup_source) {
 439                 regmap_write(pcf85363->regmap, CTRL_FLAGS, 0);
 440                 regmap_update_bits(pcf85363->regmap, CTRL_PIN_IO,
 441                                    PIN_IO_INTAPM, PIN_IO_INTA_OUT);
 442         }
 443
 444         if (client->irq > 0) {
 445                 unsigned long irqflags = IRQF_TRIGGER_LOW;
 446
 447                 if (dev_fwnode(&client->dev))
 448                         irqflags = 0;
 449                 ret = devm_request_threaded_irq(&client->dev, client->irq,
 450                                                 NULL, pcf85363_rtc_handle_irq,
 451                                                 irqflags | IRQF_ONESHOT,
 452                                                 "pcf85363", client);
 453                 if (ret) {
 454                         dev_warn(&client->dev,
 455                                  "unable to request IRQ, alarms disabled\n");
 456                         client->irq = 0;
 457                 }
 458         }
 459
 460         if (client->irq > 0 || wakeup_source) {
 461                 device_init_wakeup(&client->dev, true);
 462                 set_bit(RTC_FEATURE_ALARM, pcf85363->rtc->features);
 463         } else {
 464                 clear_bit(RTC_FEATURE_ALARM, pcf85363->rtc->features);
 465         }
 466
 467         ret = devm_rtc_register_device(pcf85363->rtc);
 468
 469         for (i = 0; i < config->num_nvram; i++) {
 470                 nvmem_cfg[i].priv = pcf85363;
 471                 devm_rtc_nvmem_register(pcf85363->rtc, &nvmem_cfg[i]);
 472         }
 473
 474         return ret;
 475 }
 476
 477 static const __maybe_unused struct of_device_id dev_ids[] = {
 478         { .compatible = "nxp,pcf85263", .data = &pcf_85263_config },
 479         { .compatible = "nxp,pcf85363", .data = &pcf_85363_config },
 480         { /* sentinel */ }
 481 };
 482 MODULE_DEVICE_TABLE(of, dev_ids);
 483
 484 static struct i2c_driver pcf85363_driver = {
 485         .driver = {
 486                 .name   = "pcf85363",
 487                 .of_match_table = of_match_ptr(dev_ids),
 488         },
 489         .probe = pcf85363_probe,
 490 };
 491
 492 module_i2c_driver(pcf85363_driver);
 493
 494 MODULE_AUTHOR("Eric Nelson");
 495 MODULE_DESCRIPTION("pcf85263/pcf85363 I2C RTC driver");
 496 MODULE_LICENSE("GPL");