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