drivers/rtc/rv3029.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2018 Theobroma Systems Design und Consulting GmbH
   4  *
   5  * Based on a the Linux rtc-rv3029c2.c driver written by:
   6  *   Gregory Hermant <gregory.hermant@calao-systems.com>
   7  *   Michael Buesch <m@bues.ch>
   8  */
   9
  10 #include <common.h>
  11 #include <command.h>
  12 #include <dm.h>
  13 #include <eeprom.h>
  14 #include <i2c.h>
  15 #include <log.h>
  16 #include <rtc.h>
  17 #include <dm/device_compat.h>
  18
  19 #define RTC_RV3029_PAGE_LEN             7
  20
  21 /* control section */
  22 #define RV3029_ONOFF_CTRL               0x00
  23 #define RV3029_ONOFF_CTRL_WE            BIT(0)
  24 #define RV3029_ONOFF_CTRL_TE            BIT(1)
  25 #define RV3029_ONOFF_CTRL_TAR           BIT(2)
  26 #define RV3029_ONOFF_CTRL_EERE          BIT(3)
  27 #define RV3029_ONOFF_CTRL_SRON          BIT(4)
  28 #define RV3029_ONOFF_CTRL_TD0           BIT(5)
  29 #define RV3029_ONOFF_CTRL_TD1           BIT(6)
  30 #define RV3029_ONOFF_CTRL_CLKINT        BIT(7)
  31 #define RV3029_IRQ_CTRL                 0x01
  32 #define RV3029_IRQ_CTRL_AIE             BIT(0)
  33 #define RV3029_IRQ_CTRL_TIE             BIT(1)
  34 #define RV3029_IRQ_CTRL_V1IE            BIT(2)
  35 #define RV3029_IRQ_CTRL_V2IE            BIT(3)
  36 #define RV3029_IRQ_CTRL_SRIE            BIT(4)
  37 #define RV3029_IRQ_FLAGS                0x02
  38 #define RV3029_IRQ_FLAGS_AF             BIT(0)
  39 #define RV3029_IRQ_FLAGS_TF             BIT(1)
  40 #define RV3029_IRQ_FLAGS_V1IF           BIT(2)
  41 #define RV3029_IRQ_FLAGS_V2IF           BIT(3)
  42 #define RV3029_IRQ_FLAGS_SRF            BIT(4)
  43 #define RV3029_STATUS                   0x03
  44 #define RV3029_STATUS_VLOW1             BIT(2)
  45 #define RV3029_STATUS_VLOW2             BIT(3)
  46 #define RV3029_STATUS_SR                BIT(4)
  47 #define RV3029_STATUS_PON               BIT(5)
  48 #define RV3029_STATUS_EEBUSY            BIT(7)
  49 #define RV3029_RST_CTRL                 0x04
  50 #define RV3029_RST_CTRL_SYSR            BIT(4)
  51 #define RV3029_CONTROL_SECTION_LEN      0x05
  52
  53 /* watch section */
  54 #define RV3029_W_SEC                    0x08
  55 #define RV3029_W_MINUTES                0x09
  56 #define RV3029_W_HOURS                  0x0A
  57 #define RV3029_REG_HR_12_24             BIT(6) /* 24h/12h mode */
  58 #define RV3029_REG_HR_PM                BIT(5) /* PM/AM bit in 12h mode */
  59 #define RV3029_W_DATE                   0x0B
  60 #define RV3029_W_DAYS                   0x0C
  61 #define RV3029_W_MONTHS                 0x0D
  62 #define RV3029_W_YEARS                  0x0E
  63
  64 /* eeprom control section */
  65 #define RV3029_CONTROL_E2P_EECTRL       0x30
  66 #define RV3029_TRICKLE_1K               BIT(4) /* 1.5K resistance */
  67 #define RV3029_TRICKLE_5K               BIT(5) /* 5K   resistance */
  68 #define RV3029_TRICKLE_20K              BIT(6) /* 20K  resistance */
  69 #define RV3029_TRICKLE_80K              BIT(7) /* 80K  resistance */
  70 #define RV3029_TRICKLE_MASK             (RV3029_TRICKLE_1K |\
  71                                          RV3029_TRICKLE_5K |\
  72                                          RV3029_TRICKLE_20K |\
  73                                          RV3029_TRICKLE_80K)
  74 #define RV3029_TRICKLE_SHIFT            4
  75
  76
  77 static int rv3029_rtc_get(struct udevice *dev, struct rtc_time *tm)
  78 {
  79         u8 regs[RTC_RV3029_PAGE_LEN];
  80         int ret;
  81
  82         ret = dm_i2c_read(dev, RV3029_W_SEC, regs, sizeof(regs));
  83         if (ret < 0) {
  84                 printf("%s: error reading RTC: %x\n", __func__, ret);
  85                 return -EIO;
  86         }
  87
  88         tm->tm_sec = bcd2bin(regs[RV3029_W_SEC - RV3029_W_SEC]);
  89         tm->tm_min = bcd2bin(regs[RV3029_W_MINUTES - RV3029_W_SEC]);
  90
  91         /* HR field has a more complex interpretation */
  92         {
  93                 const u8 _hr = regs[RV3029_W_HOURS - RV3029_W_SEC];
  94
  95                 if (_hr & RV3029_REG_HR_12_24) {
  96                         /* 12h format */
  97                         tm->tm_hour = bcd2bin(_hr & 0x1f);
  98                         if (_hr & RV3029_REG_HR_PM)     /* PM flag set */
  99                                 tm->tm_hour += 12;
 100                 } else {
 101                         /* 24h format */
 102                         tm->tm_hour = bcd2bin(_hr & 0x3f);
 103                 }
 104         }
 105
 106         tm->tm_mday = bcd2bin(regs[RV3029_W_DATE - RV3029_W_SEC]);
 107         tm->tm_mon = bcd2bin(regs[RV3029_W_MONTHS - RV3029_W_SEC]) - 1;
 108         /* RTC supports only years > 1999 */
 109         tm->tm_year = bcd2bin(regs[RV3029_W_YEARS - RV3029_W_SEC]) + 2000;
 110         tm->tm_wday = bcd2bin(regs[RV3029_W_DAYS - RV3029_W_SEC]) - 1;
 111
 112         tm->tm_yday = 0;
 113         tm->tm_isdst = 0;
 114
 115         debug("%s: %4d-%02d-%02d (wday=%d) %2d:%02d:%02d\n",
 116               __func__, tm->tm_year, tm->tm_mon, tm->tm_mday,
 117               tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
 118
 119         return 0;
 120 }
 121
 122 static int rv3029_rtc_set(struct udevice *dev, const struct rtc_time *tm)
 123 {
 124         u8 regs[RTC_RV3029_PAGE_LEN];
 125
 126         debug("%s: %4d-%02d-%02d (wday=%d( %2d:%02d:%02d\n",
 127               __func__, tm->tm_year, tm->tm_mon, tm->tm_mday,
 128               tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
 129
 130
 131         if (tm->tm_year < 2000) {
 132                 printf("%s: year %d (before 2000) not supported\n",
 133                        __func__, tm->tm_year);
 134                 return -EINVAL;
 135         }
 136
 137         regs[RV3029_W_SEC - RV3029_W_SEC] = bin2bcd(tm->tm_sec);
 138         regs[RV3029_W_MINUTES - RV3029_W_SEC] = bin2bcd(tm->tm_min);
 139         regs[RV3029_W_HOURS - RV3029_W_SEC] = bin2bcd(tm->tm_hour);
 140         regs[RV3029_W_DATE - RV3029_W_SEC] = bin2bcd(tm->tm_mday);
 141         regs[RV3029_W_MONTHS - RV3029_W_SEC] = bin2bcd(tm->tm_mon + 1);
 142         regs[RV3029_W_DAYS - RV3029_W_SEC] = bin2bcd(tm->tm_wday + 1) & 0x7;
 143         regs[RV3029_W_YEARS - RV3029_W_SEC] = bin2bcd(tm->tm_year - 2000);
 144
 145         return dm_i2c_write(dev, RV3029_W_SEC, regs, sizeof(regs));
 146 }
 147
 148 static int rv3029_rtc_reset(struct udevice *dev)
 149 {
 150         u8 ctrl = RV3029_RST_CTRL_SYSR;
 151         unsigned long start;
 152         const unsigned long timeout_ms = 10000;
 153         int ret;
 154
 155         /* trigger the system-reset */
 156         ret = dm_i2c_write(dev, RV3029_RST_CTRL, &ctrl, 1);
 157         if (ret < 0)
 158                 return -EIO;
 159
 160         /* wait for the system-reset to complete */
 161         start = get_timer(0);
 162         do {
 163                 if (get_timer(start) > timeout_ms)
 164                         return -ETIMEDOUT;
 165
 166                 ret = dm_i2c_read(dev, RV3029_RST_CTRL, &ctrl, 1);
 167                 if (ret < 0)
 168                         return -EIO;
 169         } while (ctrl & RV3029_RST_CTRL_SYSR);
 170
 171         return 0;
 172 }
 173
 174 static int rv3029_rtc_read8(struct udevice *dev, unsigned int reg)
 175 {
 176         u8 data;
 177         int ret;
 178
 179         ret = dm_i2c_read(dev, reg, &data, sizeof(data));
 180         return ret < 0 ? ret : data;
 181 }
 182
 183 static int rv3029_rtc_write8(struct udevice *dev, unsigned int reg, int val)
 184 {
 185         u8 data = val;
 186
 187         return dm_i2c_write(dev, reg, &data, 1);
 188 }
 189
 190 #if defined(OF_CONTROL)
 191 static int rv3029_get_sr(struct udevice *dev, u8 *buf)
 192 {
 193         int ret = dm_i2c_read(dev, RV3029_STATUS, buf, 1);
 194
 195         if (ret < 0)
 196                 return -EIO;
 197
 198         dev_dbg(dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
 199         return 0;
 200 }
 201
 202 static int rv3029_set_sr(struct udevice *dev, u8 val)
 203 {
 204         int ret;
 205
 206         ret = dm_i2c_read(dev, RV3029_STATUS, &val, 1);
 207         if (ret < 0)
 208                 return -EIO;
 209
 210         dev_dbg(dev, "status = 0x%.2x (%d)\n", val, val);
 211         return 0;
 212 }
 213
 214 static int rv3029_eeprom_busywait(struct udevice *dev)
 215 {
 216         int i, ret;
 217         u8 sr;
 218
 219         for (i = 100; i > 0; i--) {
 220                 ret = rv3029_get_sr(dev, &sr);
 221                 if (ret < 0)
 222                         break;
 223                 if (!(sr & RV3029_STATUS_EEBUSY))
 224                         break;
 225                 udelay(10000);
 226         }
 227         if (i <= 0) {
 228                 dev_err(dev, "EEPROM busy wait timeout.\n");
 229                 return -ETIMEDOUT;
 230         }
 231
 232         return ret;
 233 }
 234
 235 static int rv3029_update_bits(struct udevice *dev, u8 reg, u8 mask, u8 set)
 236 {
 237         u8 buf;
 238         int ret;
 239
 240         ret = dm_i2c_read(dev, reg, &buf, 1);
 241         if (ret < 0)
 242                 return ret;
 243
 244         if ((buf & mask) == (set && mask))
 245                 return 0;
 246
 247         buf = (buf & ~mask) | (set & mask);
 248         ret = dm_i2c_read(dev, reg, &buf, 1);
 249         if (ret < 0)
 250                 return ret;
 251
 252         return 0;
 253 }
 254
 255 static int rv3029_eeprom_exit(struct udevice *dev)
 256 {
 257         /* Re-enable eeprom refresh */
 258         return rv3029_update_bits(dev, RV3029_ONOFF_CTRL,
 259                                   RV3029_ONOFF_CTRL_EERE,
 260                                   RV3029_ONOFF_CTRL_EERE);
 261 }
 262
 263 static int rv3029_eeprom_enter(struct udevice *dev)
 264 {
 265         int ret;
 266         u8 sr;
 267
 268         /* Check whether we are in the allowed voltage range. */
 269         ret = rv3029_get_sr(dev, &sr);
 270         if (ret < 0)
 271                 return ret;
 272         if (sr & (RV3029_STATUS_VLOW1 | RV3029_STATUS_VLOW2)) {
 273                 /* We clear the bits and retry once just in case
 274                  * we had a brown out in early startup.
 275                  */
 276                 sr &= ~RV3029_STATUS_VLOW1;
 277                 sr &= ~RV3029_STATUS_VLOW2;
 278                 ret = rv3029_set_sr(dev, sr);
 279                 if (ret < 0)
 280                         return ret;
 281                 udelay(10000);
 282                 ret = rv3029_get_sr(dev, &sr);
 283                 if (ret < 0)
 284                         return ret;
 285                 if (sr & (RV3029_STATUS_VLOW1 | RV3029_STATUS_VLOW2)) {
 286                         dev_err(dev, "Supply voltage is too low to safely access the EEPROM.\n");
 287                         return -ENODEV;
 288                 }
 289         }
 290
 291         /* Disable eeprom refresh. */
 292         ret = rv3029_update_bits(dev,
 293                                  RV3029_ONOFF_CTRL, RV3029_ONOFF_CTRL_EERE, 0);
 294         if (ret < 0)
 295                 return ret;
 296
 297         /* Wait for any previous eeprom accesses to finish. */
 298         ret = rv3029_eeprom_busywait(dev);
 299         if (ret < 0)
 300                 rv3029_eeprom_exit(dev);
 301
 302         return ret;
 303 }
 304
 305 static int rv3029_eeprom_read(struct udevice *dev, u8 reg,
 306                               u8 buf[], size_t len)
 307 {
 308         int ret, err;
 309
 310         err = rv3029_eeprom_enter(dev);
 311         if (err < 0)
 312                 return err;
 313
 314         ret = dm_i2c_read(dev, reg, buf, len);
 315
 316         err = rv3029_eeprom_exit(dev);
 317         if (err < 0)
 318                 return err;
 319
 320         return ret;
 321 }
 322
 323 static int rv3029_eeprom_write(struct udevice *dev, u8 reg,
 324                                u8 const buf[], size_t len)
 325 {
 326         int ret;
 327         size_t i;
 328         u8 tmp;
 329
 330         ret = rv3029_eeprom_enter(dev);
 331         if (ret < 0)
 332                 return ret;
 333
 334         for (i = 0; i < len; i++, reg++) {
 335                 ret = dm_i2c_read(dev, reg, &tmp, 1);
 336                 if (ret < 0)
 337                         break;
 338                 if (tmp != buf[i]) {
 339                         ret = dm_i2c_write(dev, reg, &buf[i], 1);
 340                         if (ret < 0)
 341                                 break;
 342                 }
 343                 ret = rv3029_eeprom_busywait(dev);
 344                 if (ret < 0)
 345                         break;
 346         }
 347
 348         ret = rv3029_eeprom_exit(dev);
 349         if (ret < 0)
 350                 return ret;
 351
 352         return 0;
 353 }
 354
 355 static int rv3029_eeprom_update_bits(struct udevice *dev,
 356                                      u8 reg, u8 mask, u8 set)
 357 {
 358         u8 buf;
 359         int ret;
 360
 361         ret = rv3029_eeprom_read(dev, reg, &buf, 1);
 362         if (ret < 0)
 363                 return ret;
 364
 365         /*
 366          * If the EEPROM already reads the correct bitpattern, we don't need
 367          * to update it.
 368          */
 369         if ((buf & mask) == (set & mask))
 370                 return 0;
 371
 372         buf = (buf & ~mask) | (set & mask);
 373         ret = rv3029_eeprom_write(dev, reg, &buf, 1);
 374         if (ret < 0)
 375                 return ret;
 376
 377         return 0;
 378 }
 379
 380 static void rv3029_trickle_config(struct udevice *dev)
 381 {
 382         static const struct rv3029_trickle_tab_elem {
 383                 u32 r;          /* resistance in ohms */
 384                 u8 conf;        /* trickle config bits */
 385         } rv3029_trickle_tab[] = {
 386                 {
 387                         .r      = 1076,
 388                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
 389                                   RV3029_TRICKLE_20K | RV3029_TRICKLE_80K,
 390                 }, {
 391                         .r      = 1091,
 392                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
 393                                   RV3029_TRICKLE_20K,
 394                 }, {
 395                         .r      = 1137,
 396                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
 397                                   RV3029_TRICKLE_80K,
 398                 }, {
 399                         .r      = 1154,
 400                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K,
 401                 }, {
 402                         .r      = 1371,
 403                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_20K |
 404                                   RV3029_TRICKLE_80K,
 405                 }, {
 406                         .r      = 1395,
 407                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_20K,
 408                 }, {
 409                         .r      = 1472,
 410                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_80K,
 411                 }, {
 412                         .r      = 1500,
 413                         .conf   = RV3029_TRICKLE_1K,
 414                 }, {
 415                         .r      = 3810,
 416                         .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_20K |
 417                                   RV3029_TRICKLE_80K,
 418                 }, {
 419                         .r      = 4000,
 420                         .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_20K,
 421                 }, {
 422                         .r      = 4706,
 423                         .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_80K,
 424                 }, {
 425                         .r      = 5000,
 426                         .conf   = RV3029_TRICKLE_5K,
 427                 }, {
 428                         .r      = 16000,
 429                         .conf   = RV3029_TRICKLE_20K | RV3029_TRICKLE_80K,
 430                 }, {
 431                         .r      = 20000,
 432                         .conf   = RV3029_TRICKLE_20K,
 433                 }, {
 434                         .r      = 80000,
 435                         .conf   = RV3029_TRICKLE_80K,
 436                 },
 437         };
 438         int err;
 439         u32 ohms;
 440         u8 trickle_set_bits = 0;
 441
 442         /* Configure the trickle charger. */
 443         err = dev_read_u32(dev, "trickle-resistor-ohms", &ohms);
 444
 445         if (!err) {
 446                 /* Find trickle-charger config */
 447                 for (int i = 0; i < ARRAY_SIZE(rv3029_trickle_tab); i++)
 448                         if (rv3029_trickle_tab[i].r >= ohms) {
 449                                 dev_dbg(dev, "trickle charger at %d ohms\n",
 450                                         rv3029_trickle_tab[i].r);
 451                                 trickle_set_bits = rv3029_trickle_tab[i].conf;
 452                                 break;
 453                         }
 454         }
 455
 456         dev_dbg(dev, "trickle charger config 0x%x\n", trickle_set_bits);
 457         err = rv3029_eeprom_update_bits(dev, RV3029_CONTROL_E2P_EECTRL,
 458                                         RV3029_TRICKLE_MASK,
 459                                         trickle_set_bits);
 460         if (err < 0)
 461                 dev_dbg(dev, "failed to update trickle charger\n");
 462 }
 463 #else
 464 static inline void rv3029_trickle_config(struct udevice *dev)
 465 {
 466 }
 467 #endif
 468
 469 static int rv3029_probe(struct udevice *dev)
 470 {
 471         i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
 472                                 DM_I2C_CHIP_WR_ADDRESS);
 473
 474         rv3029_trickle_config(dev);
 475         return 0;
 476 }
 477
 478 static const struct rtc_ops rv3029_rtc_ops = {
 479         .get = rv3029_rtc_get,
 480         .set = rv3029_rtc_set,
 481         .read8 = rv3029_rtc_read8,
 482         .write8 = rv3029_rtc_write8,
 483         .reset = rv3029_rtc_reset,
 484 };
 485
 486 static const struct udevice_id rv3029_rtc_ids[] = {
 487         { .compatible = "mc,rv3029" },
 488         { .compatible = "mc,rv3029c2" },
 489         { }
 490 };
 491
 492 U_BOOT_DRIVER(rtc_rv3029) = {
 493         .name   = "rtc-rv3029",
 494         .id     = UCLASS_RTC,
 495         .probe  = rv3029_probe,
 496         .of_match = rv3029_rtc_ids,
 497         .ops    = &rv3029_rtc_ops,
 498 };