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