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 #include <linux/bitops.h>
  19 #include <linux/delay.h>
  20
  21 #define RTC_RV3029_PAGE_LEN             7
  22
  23 /* control section */
  24 #define RV3029_ONOFF_CTRL               0x00
  25 #define RV3029_ONOFF_CTRL_WE            BIT(0)
  26 #define RV3029_ONOFF_CTRL_TE            BIT(1)
  27 #define RV3029_ONOFF_CTRL_TAR           BIT(2)
  28 #define RV3029_ONOFF_CTRL_EERE          BIT(3)
  29 #define RV3029_ONOFF_CTRL_SRON          BIT(4)
  30 #define RV3029_ONOFF_CTRL_TD0           BIT(5)
  31 #define RV3029_ONOFF_CTRL_TD1           BIT(6)
  32 #define RV3029_ONOFF_CTRL_CLKINT        BIT(7)
  33 #define RV3029_IRQ_CTRL                 0x01
  34 #define RV3029_IRQ_CTRL_AIE             BIT(0)
  35 #define RV3029_IRQ_CTRL_TIE             BIT(1)
  36 #define RV3029_IRQ_CTRL_V1IE            BIT(2)
  37 #define RV3029_IRQ_CTRL_V2IE            BIT(3)
  38 #define RV3029_IRQ_CTRL_SRIE            BIT(4)
  39 #define RV3029_IRQ_FLAGS                0x02
  40 #define RV3029_IRQ_FLAGS_AF             BIT(0)
  41 #define RV3029_IRQ_FLAGS_TF             BIT(1)
  42 #define RV3029_IRQ_FLAGS_V1IF           BIT(2)
  43 #define RV3029_IRQ_FLAGS_V2IF           BIT(3)
  44 #define RV3029_IRQ_FLAGS_SRF            BIT(4)
  45 #define RV3029_STATUS                   0x03
  46 #define RV3029_STATUS_VLOW1             BIT(2)
  47 #define RV3029_STATUS_VLOW2             BIT(3)
  48 #define RV3029_STATUS_SR                BIT(4)
  49 #define RV3029_STATUS_PON               BIT(5)
  50 #define RV3029_STATUS_EEBUSY            BIT(7)
  51 #define RV3029_RST_CTRL                 0x04
  52 #define RV3029_RST_CTRL_SYSR            BIT(4)
  53 #define RV3029_CONTROL_SECTION_LEN      0x05
  54
  55 /* watch section */
  56 #define RV3029_W_SEC                    0x08
  57 #define RV3029_W_MINUTES                0x09
  58 #define RV3029_W_HOURS                  0x0A
  59 #define RV3029_REG_HR_12_24             BIT(6) /* 24h/12h mode */
  60 #define RV3029_REG_HR_PM                BIT(5) /* PM/AM bit in 12h mode */
  61 #define RV3029_W_DATE                   0x0B
  62 #define RV3029_W_DAYS                   0x0C
  63 #define RV3029_W_MONTHS                 0x0D
  64 #define RV3029_W_YEARS                  0x0E
  65
  66 /* eeprom control section */
  67 #define RV3029_CONTROL_E2P_EECTRL       0x30
  68 #define RV3029_TRICKLE_1K               BIT(4) /* 1.5K resistance */
  69 #define RV3029_TRICKLE_5K               BIT(5) /* 5K   resistance */
  70 #define RV3029_TRICKLE_20K              BIT(6) /* 20K  resistance */
  71 #define RV3029_TRICKLE_80K              BIT(7) /* 80K  resistance */
  72 #define RV3029_TRICKLE_MASK             (RV3029_TRICKLE_1K |\
  73                                          RV3029_TRICKLE_5K |\
  74                                          RV3029_TRICKLE_20K |\
  75                                          RV3029_TRICKLE_80K)
  76 #define RV3029_TRICKLE_SHIFT            4
  77
  78
  79 static int rv3029_rtc_get(struct udevice *dev, struct rtc_time *tm)
  80 {
  81         u8 regs[RTC_RV3029_PAGE_LEN];
  82         int ret;
  83
  84         ret = dm_i2c_read(dev, RV3029_W_SEC, regs, sizeof(regs));
  85         if (ret < 0) {
  86                 printf("%s: error reading RTC: %x\n", __func__, ret);
  87                 return -EIO;
  88         }
  89
  90         tm->tm_sec = bcd2bin(regs[RV3029_W_SEC - RV3029_W_SEC]);
  91         tm->tm_min = bcd2bin(regs[RV3029_W_MINUTES - RV3029_W_SEC]);
  92
  93         /* HR field has a more complex interpretation */
  94         {
  95                 const u8 _hr = regs[RV3029_W_HOURS - RV3029_W_SEC];
  96
  97                 if (_hr & RV3029_REG_HR_12_24) {
  98                         /* 12h format */
  99                         tm->tm_hour = bcd2bin(_hr & 0x1f);
 100                         if (_hr & RV3029_REG_HR_PM)     /* PM flag set */
 101                                 tm->tm_hour += 12;
 102                 } else {
 103                         /* 24h format */
 104                         tm->tm_hour = bcd2bin(_hr & 0x3f);
 105                 }
 106         }
 107
 108         tm->tm_mday = bcd2bin(regs[RV3029_W_DATE - RV3029_W_SEC]);
 109         tm->tm_mon = bcd2bin(regs[RV3029_W_MONTHS - RV3029_W_SEC]) - 1;
 110         /* RTC supports only years > 1999 */
 111         tm->tm_year = bcd2bin(regs[RV3029_W_YEARS - RV3029_W_SEC]) + 2000;
 112         tm->tm_wday = bcd2bin(regs[RV3029_W_DAYS - RV3029_W_SEC]) - 1;
 113
 114         tm->tm_yday = 0;
 115         tm->tm_isdst = 0;
 116
 117         debug("%s: %4d-%02d-%02d (wday=%d) %2d:%02d:%02d\n",
 118               __func__, tm->tm_year, tm->tm_mon, tm->tm_mday,
 119               tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
 120
 121         return 0;
 122 }
 123
 124 static int rv3029_rtc_set(struct udevice *dev, const struct rtc_time *tm)
 125 {
 126         u8 regs[RTC_RV3029_PAGE_LEN];
 127
 128         debug("%s: %4d-%02d-%02d (wday=%d( %2d:%02d:%02d\n",
 129               __func__, tm->tm_year, tm->tm_mon, tm->tm_mday,
 130               tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
 131
 132
 133         if (tm->tm_year < 2000) {
 134                 printf("%s: year %d (before 2000) not supported\n",
 135                        __func__, tm->tm_year);
 136                 return -EINVAL;
 137         }
 138
 139         regs[RV3029_W_SEC - RV3029_W_SEC] = bin2bcd(tm->tm_sec);
 140         regs[RV3029_W_MINUTES - RV3029_W_SEC] = bin2bcd(tm->tm_min);
 141         regs[RV3029_W_HOURS - RV3029_W_SEC] = bin2bcd(tm->tm_hour);
 142         regs[RV3029_W_DATE - RV3029_W_SEC] = bin2bcd(tm->tm_mday);
 143         regs[RV3029_W_MONTHS - RV3029_W_SEC] = bin2bcd(tm->tm_mon + 1);
 144         regs[RV3029_W_DAYS - RV3029_W_SEC] = bin2bcd(tm->tm_wday + 1) & 0x7;
 145         regs[RV3029_W_YEARS - RV3029_W_SEC] = bin2bcd(tm->tm_year - 2000);
 146
 147         return dm_i2c_write(dev, RV3029_W_SEC, regs, sizeof(regs));
 148 }
 149
 150 static int rv3029_rtc_reset(struct udevice *dev)
 151 {
 152         u8 ctrl = RV3029_RST_CTRL_SYSR;
 153         unsigned long start;
 154         const unsigned long timeout_ms = 10000;
 155         int ret;
 156
 157         /* trigger the system-reset */
 158         ret = dm_i2c_write(dev, RV3029_RST_CTRL, &ctrl, 1);
 159         if (ret < 0)
 160                 return -EIO;
 161
 162         /* wait for the system-reset to complete */
 163         start = get_timer(0);
 164         do {
 165                 if (get_timer(start) > timeout_ms)
 166                         return -ETIMEDOUT;
 167
 168                 ret = dm_i2c_read(dev, RV3029_RST_CTRL, &ctrl, 1);
 169                 if (ret < 0)
 170                         return -EIO;
 171         } while (ctrl & RV3029_RST_CTRL_SYSR);
 172
 173         return 0;
 174 }
 175
 176 static int rv3029_rtc_read8(struct udevice *dev, unsigned int reg)
 177 {
 178         u8 data;
 179         int ret;
 180
 181         ret = dm_i2c_read(dev, reg, &data, sizeof(data));
 182         return ret < 0 ? ret : data;
 183 }
 184
 185 static int rv3029_rtc_write8(struct udevice *dev, unsigned int reg, int val)
 186 {
 187         u8 data = val;
 188
 189         return dm_i2c_write(dev, reg, &data, 1);
 190 }
 191
 192 #if defined(OF_CONTROL)
 193 static int rv3029_get_sr(struct udevice *dev, u8 *buf)
 194 {
 195         int ret = dm_i2c_read(dev, RV3029_STATUS, buf, 1);
 196
 197         if (ret < 0)
 198                 return -EIO;
 199
 200         dev_dbg(dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
 201         return 0;
 202 }
 203
 204 static int rv3029_set_sr(struct udevice *dev, u8 val)
 205 {
 206         int ret;
 207
 208         ret = dm_i2c_read(dev, RV3029_STATUS, &val, 1);
 209         if (ret < 0)
 210                 return -EIO;
 211
 212         dev_dbg(dev, "status = 0x%.2x (%d)\n", val, val);
 213         return 0;
 214 }
 215
 216 static int rv3029_eeprom_busywait(struct udevice *dev)
 217 {
 218         int i, ret;
 219         u8 sr;
 220
 221         for (i = 100; i > 0; i--) {
 222                 ret = rv3029_get_sr(dev, &sr);
 223                 if (ret < 0)
 224                         break;
 225                 if (!(sr & RV3029_STATUS_EEBUSY))
 226                         break;
 227                 udelay(10000);
 228         }
 229         if (i <= 0) {
 230                 dev_err(dev, "EEPROM busy wait timeout.\n");
 231                 return -ETIMEDOUT;
 232         }
 233
 234         return ret;
 235 }
 236
 237 static int rv3029_update_bits(struct udevice *dev, u8 reg, u8 mask, u8 set)
 238 {
 239         u8 buf;
 240         int ret;
 241
 242         ret = dm_i2c_read(dev, reg, &buf, 1);
 243         if (ret < 0)
 244                 return ret;
 245
 246         if ((buf & mask) == (set && mask))
 247                 return 0;
 248
 249         buf = (buf & ~mask) | (set & mask);
 250         ret = dm_i2c_read(dev, reg, &buf, 1);
 251         if (ret < 0)
 252                 return ret;
 253
 254         return 0;
 255 }
 256
 257 static int rv3029_eeprom_exit(struct udevice *dev)
 258 {
 259         /* Re-enable eeprom refresh */
 260         return rv3029_update_bits(dev, RV3029_ONOFF_CTRL,
 261                                   RV3029_ONOFF_CTRL_EERE,
 262                                   RV3029_ONOFF_CTRL_EERE);
 263 }
 264
 265 static int rv3029_eeprom_enter(struct udevice *dev)
 266 {
 267         int ret;
 268         u8 sr;
 269
 270         /* Check whether we are in the allowed voltage range. */
 271         ret = rv3029_get_sr(dev, &sr);
 272         if (ret < 0)
 273                 return ret;
 274         if (sr & (RV3029_STATUS_VLOW1 | RV3029_STATUS_VLOW2)) {
 275                 /* We clear the bits and retry once just in case
 276                  * we had a brown out in early startup.
 277                  */
 278                 sr &= ~RV3029_STATUS_VLOW1;
 279                 sr &= ~RV3029_STATUS_VLOW2;
 280                 ret = rv3029_set_sr(dev, sr);
 281                 if (ret < 0)
 282                         return ret;
 283                 udelay(10000);
 284                 ret = rv3029_get_sr(dev, &sr);
 285                 if (ret < 0)
 286                         return ret;
 287                 if (sr & (RV3029_STATUS_VLOW1 | RV3029_STATUS_VLOW2)) {
 288                         dev_err(dev, "Supply voltage is too low to safely access the EEPROM.\n");
 289                         return -ENODEV;
 290                 }
 291         }
 292
 293         /* Disable eeprom refresh. */
 294         ret = rv3029_update_bits(dev,
 295                                  RV3029_ONOFF_CTRL, RV3029_ONOFF_CTRL_EERE, 0);
 296         if (ret < 0)
 297                 return ret;
 298
 299         /* Wait for any previous eeprom accesses to finish. */
 300         ret = rv3029_eeprom_busywait(dev);
 301         if (ret < 0)
 302                 rv3029_eeprom_exit(dev);
 303
 304         return ret;
 305 }
 306
 307 static int rv3029_eeprom_read(struct udevice *dev, u8 reg,
 308                               u8 buf[], size_t len)
 309 {
 310         int ret, err;
 311
 312         err = rv3029_eeprom_enter(dev);
 313         if (err < 0)
 314                 return err;
 315
 316         ret = dm_i2c_read(dev, reg, buf, len);
 317
 318         err = rv3029_eeprom_exit(dev);
 319         if (err < 0)
 320                 return err;
 321
 322         return ret;
 323 }
 324
 325 static int rv3029_eeprom_write(struct udevice *dev, u8 reg,
 326                                u8 const buf[], size_t len)
 327 {
 328         int ret;
 329         size_t i;
 330         u8 tmp;
 331
 332         ret = rv3029_eeprom_enter(dev);
 333         if (ret < 0)
 334                 return ret;
 335
 336         for (i = 0; i < len; i++, reg++) {
 337                 ret = dm_i2c_read(dev, reg, &tmp, 1);
 338                 if (ret < 0)
 339                         break;
 340                 if (tmp != buf[i]) {
 341                         ret = dm_i2c_write(dev, reg, &buf[i], 1);
 342                         if (ret < 0)
 343                                 break;
 344                 }
 345                 ret = rv3029_eeprom_busywait(dev);
 346                 if (ret < 0)
 347                         break;
 348         }
 349
 350         ret = rv3029_eeprom_exit(dev);
 351         if (ret < 0)
 352                 return ret;
 353
 354         return 0;
 355 }
 356
 357 static int rv3029_eeprom_update_bits(struct udevice *dev,
 358                                      u8 reg, u8 mask, u8 set)
 359 {
 360         u8 buf;
 361         int ret;
 362
 363         ret = rv3029_eeprom_read(dev, reg, &buf, 1);
 364         if (ret < 0)
 365                 return ret;
 366
 367         /*
 368          * If the EEPROM already reads the correct bitpattern, we don't need
 369          * to update it.
 370          */
 371         if ((buf & mask) == (set & mask))
 372                 return 0;
 373
 374         buf = (buf & ~mask) | (set & mask);
 375         ret = rv3029_eeprom_write(dev, reg, &buf, 1);
 376         if (ret < 0)
 377                 return ret;
 378
 379         return 0;
 380 }
 381
 382 static void rv3029_trickle_config(struct udevice *dev)
 383 {
 384         static const struct rv3029_trickle_tab_elem {
 385                 u32 r;          /* resistance in ohms */
 386                 u8 conf;        /* trickle config bits */
 387         } rv3029_trickle_tab[] = {
 388                 {
 389                         .r      = 1076,
 390                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
 391                                   RV3029_TRICKLE_20K | RV3029_TRICKLE_80K,
 392                 }, {
 393                         .r      = 1091,
 394                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
 395                                   RV3029_TRICKLE_20K,
 396                 }, {
 397                         .r      = 1137,
 398                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
 399                                   RV3029_TRICKLE_80K,
 400                 }, {
 401                         .r      = 1154,
 402                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K,
 403                 }, {
 404                         .r      = 1371,
 405                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_20K |
 406                                   RV3029_TRICKLE_80K,
 407                 }, {
 408                         .r      = 1395,
 409                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_20K,
 410                 }, {
 411                         .r      = 1472,
 412                         .conf   = RV3029_TRICKLE_1K | RV3029_TRICKLE_80K,
 413                 }, {
 414                         .r      = 1500,
 415                         .conf   = RV3029_TRICKLE_1K,
 416                 }, {
 417                         .r      = 3810,
 418                         .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_20K |
 419                                   RV3029_TRICKLE_80K,
 420                 }, {
 421                         .r      = 4000,
 422                         .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_20K,
 423                 }, {
 424                         .r      = 4706,
 425                         .conf   = RV3029_TRICKLE_5K | RV3029_TRICKLE_80K,
 426                 }, {
 427                         .r      = 5000,
 428                         .conf   = RV3029_TRICKLE_5K,
 429                 }, {
 430                         .r      = 16000,
 431                         .conf   = RV3029_TRICKLE_20K | RV3029_TRICKLE_80K,
 432                 }, {
 433                         .r      = 20000,
 434                         .conf   = RV3029_TRICKLE_20K,
 435                 }, {
 436                         .r      = 80000,
 437                         .conf   = RV3029_TRICKLE_80K,
 438                 },
 439         };
 440         int err;
 441         u32 ohms;
 442         u8 trickle_set_bits = 0;
 443
 444         /* Configure the trickle charger. */
 445         err = dev_read_u32(dev, "trickle-resistor-ohms", &ohms);
 446
 447         if (!err) {
 448                 /* Find trickle-charger config */
 449                 for (int i = 0; i < ARRAY_SIZE(rv3029_trickle_tab); i++)
 450                         if (rv3029_trickle_tab[i].r >= ohms) {
 451                                 dev_dbg(dev, "trickle charger at %d ohms\n",
 452                                         rv3029_trickle_tab[i].r);
 453                                 trickle_set_bits = rv3029_trickle_tab[i].conf;
 454                                 break;
 455                         }
 456         }
 457
 458         dev_dbg(dev, "trickle charger config 0x%x\n", trickle_set_bits);
 459         err = rv3029_eeprom_update_bits(dev, RV3029_CONTROL_E2P_EECTRL,
 460                                         RV3029_TRICKLE_MASK,
 461                                         trickle_set_bits);
 462         if (err < 0)
 463                 dev_dbg(dev, "failed to update trickle charger\n");
 464 }
 465 #else
 466 static inline void rv3029_trickle_config(struct udevice *dev)
 467 {
 468 }
 469 #endif
 470
 471 static int rv3029_probe(struct udevice *dev)
 472 {
 473         i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
 474                                 DM_I2C_CHIP_WR_ADDRESS);
 475
 476         rv3029_trickle_config(dev);
 477         return 0;
 478 }
 479
 480 static const struct rtc_ops rv3029_rtc_ops = {
 481         .get = rv3029_rtc_get,
 482         .set = rv3029_rtc_set,
 483         .read8 = rv3029_rtc_read8,
 484         .write8 = rv3029_rtc_write8,
 485         .reset = rv3029_rtc_reset,
 486 };
 487
 488 static const struct udevice_id rv3029_rtc_ids[] = {
 489         { .compatible = "mc,rv3029" },
 490         { .compatible = "mc,rv3029c2" },
 491         { }
 492 };
 493
 494 U_BOOT_DRIVER(rtc_rv3029) = {
 495         .name   = "rtc-rv3029",
 496         .id     = UCLASS_RTC,
 497         .probe  = rv3029_probe,
 498         .of_match = rv3029_rtc_ids,
 499         .ops    = &rv3029_rtc_ops,
 500 };