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