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