drivers/rtc/rtc-ab-eoz9.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Real Time Clock driver for AB-RTCMC-32.768kHz-EOZ9 chip.
   4  * Copyright (C) 2019 Orolia
   5  *
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/rtc.h>
  10 #include <linux/i2c.h>
  11 #include <linux/bcd.h>
  12 #include <linux/of.h>
  13 #include <linux/regmap.h>
  14 #include <linux/hwmon.h>
  15 #include <linux/hwmon-sysfs.h>
  16
  17 #define ABEOZ9_REG_CTRL1                0x00
  18 #define ABEOZ9_REG_CTRL1_MASK           GENMASK(7, 0)
  19 #define ABEOZ9_REG_CTRL1_WE             BIT(0)
  20 #define ABEOZ9_REG_CTRL1_TE             BIT(1)
  21 #define ABEOZ9_REG_CTRL1_TAR            BIT(2)
  22 #define ABEOZ9_REG_CTRL1_EERE           BIT(3)
  23 #define ABEOZ9_REG_CTRL1_SRON           BIT(4)
  24 #define ABEOZ9_REG_CTRL1_TD0            BIT(5)
  25 #define ABEOZ9_REG_CTRL1_TD1            BIT(6)
  26 #define ABEOZ9_REG_CTRL1_CLKINT         BIT(7)
  27
  28 #define ABEOZ9_REG_CTRL_INT             0x01
  29 #define ABEOZ9_REG_CTRL_INT_AIE         BIT(0)
  30 #define ABEOZ9_REG_CTRL_INT_TIE         BIT(1)
  31 #define ABEOZ9_REG_CTRL_INT_V1IE        BIT(2)
  32 #define ABEOZ9_REG_CTRL_INT_V2IE        BIT(3)
  33 #define ABEOZ9_REG_CTRL_INT_SRIE        BIT(4)
  34
  35 #define ABEOZ9_REG_CTRL_INT_FLAG        0x02
  36 #define ABEOZ9_REG_CTRL_INT_FLAG_AF     BIT(0)
  37 #define ABEOZ9_REG_CTRL_INT_FLAG_TF     BIT(1)
  38 #define ABEOZ9_REG_CTRL_INT_FLAG_V1IF   BIT(2)
  39 #define ABEOZ9_REG_CTRL_INT_FLAG_V2IF   BIT(3)
  40 #define ABEOZ9_REG_CTRL_INT_FLAG_SRF    BIT(4)
  41
  42 #define ABEOZ9_REG_CTRL_STATUS          0x03
  43 #define ABEOZ9_REG_CTRL_STATUS_V1F      BIT(2)
  44 #define ABEOZ9_REG_CTRL_STATUS_V2F      BIT(3)
  45 #define ABEOZ9_REG_CTRL_STATUS_SR       BIT(4)
  46 #define ABEOZ9_REG_CTRL_STATUS_PON      BIT(5)
  47 #define ABEOZ9_REG_CTRL_STATUS_EEBUSY   BIT(7)
  48
  49 #define ABEOZ9_REG_SEC                  0x08
  50 #define ABEOZ9_REG_MIN                  0x09
  51 #define ABEOZ9_REG_HOURS                0x0A
  52 #define ABEOZ9_HOURS_PM                 BIT(6)
  53 #define ABEOZ9_REG_DAYS                 0x0B
  54 #define ABEOZ9_REG_WEEKDAYS             0x0C
  55 #define ABEOZ9_REG_MONTHS               0x0D
  56 #define ABEOZ9_REG_YEARS                0x0E
  57
  58 #define ABEOZ9_SEC_LEN                  7
  59
  60 #define ABEOZ9_REG_REG_TEMP             0x20
  61 #define ABEOZ953_TEMP_MAX               120
  62 #define ABEOZ953_TEMP_MIN               -60
  63
  64 #define ABEOZ9_REG_EEPROM               0x30
  65 #define ABEOZ9_REG_EEPROM_MASK          GENMASK(8, 0)
  66 #define ABEOZ9_REG_EEPROM_THP           BIT(0)
  67 #define ABEOZ9_REG_EEPROM_THE           BIT(1)
  68 #define ABEOZ9_REG_EEPROM_FD0           BIT(2)
  69 #define ABEOZ9_REG_EEPROM_FD1           BIT(3)
  70 #define ABEOZ9_REG_EEPROM_R1K           BIT(4)
  71 #define ABEOZ9_REG_EEPROM_R5K           BIT(5)
  72 #define ABEOZ9_REG_EEPROM_R20K          BIT(6)
  73 #define ABEOZ9_REG_EEPROM_R80K          BIT(7)
  74
  75 struct abeoz9_rtc_data {
  76         struct rtc_device *rtc;
  77         struct regmap *regmap;
  78         struct device *hwmon_dev;
  79 };
  80
  81 static int abeoz9_check_validity(struct device *dev)
  82 {
  83         struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
  84         struct regmap *regmap = data->regmap;
  85         int ret;
  86         int val;
  87
  88         ret = regmap_read(regmap, ABEOZ9_REG_CTRL_STATUS, &val);
  89         if (ret < 0) {
  90                 dev_err(dev,
  91                         "unable to get CTRL_STATUS register (%d)\n", ret);
  92                 return ret;
  93         }
  94
  95         if (val & ABEOZ9_REG_CTRL_STATUS_PON) {
  96                 dev_warn(dev, "power-on reset detected, date is invalid\n");
  97                 return -EINVAL;
  98         }
  99
 100         if (val & ABEOZ9_REG_CTRL_STATUS_V1F) {
 101                 dev_warn(dev,
 102                          "voltage drops below VLOW1 threshold, date is invalid\n");
 103                 return -EINVAL;
 104         }
 105
 106         if ((val & ABEOZ9_REG_CTRL_STATUS_V2F)) {
 107                 dev_warn(dev,
 108                          "voltage drops below VLOW2 threshold, date is invalid\n");
 109                 return -EINVAL;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static int abeoz9_reset_validity(struct regmap *regmap)
 116 {
 117         return regmap_update_bits(regmap, ABEOZ9_REG_CTRL_STATUS,
 118                                   ABEOZ9_REG_CTRL_STATUS_V1F |
 119                                   ABEOZ9_REG_CTRL_STATUS_V2F |
 120                                   ABEOZ9_REG_CTRL_STATUS_PON,
 121                                   0);
 122 }
 123
 124 static int abeoz9_rtc_get_time(struct device *dev, struct rtc_time *tm)
 125 {
 126         struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 127         u8 regs[ABEOZ9_SEC_LEN];
 128         int ret;
 129
 130         ret = abeoz9_check_validity(dev);
 131         if (ret)
 132                 return ret;
 133
 134         ret = regmap_bulk_read(data->regmap, ABEOZ9_REG_SEC,
 135                                regs,
 136                                sizeof(regs));
 137         if (ret) {
 138                 dev_err(dev, "reading RTC time failed (%d)\n", ret);
 139                 return ret;
 140         }
 141
 142         tm->tm_sec = bcd2bin(regs[ABEOZ9_REG_SEC - ABEOZ9_REG_SEC] & 0x7F);
 143         tm->tm_min = bcd2bin(regs[ABEOZ9_REG_MIN - ABEOZ9_REG_SEC] & 0x7F);
 144
 145         if (regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & ABEOZ9_HOURS_PM) {
 146                 tm->tm_hour =
 147                         bcd2bin(regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & 0x1f);
 148                 if (regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] & ABEOZ9_HOURS_PM)
 149                         tm->tm_hour += 12;
 150         } else {
 151                 tm->tm_hour = bcd2bin(regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC]);
 152         }
 153
 154         tm->tm_mday = bcd2bin(regs[ABEOZ9_REG_DAYS - ABEOZ9_REG_SEC]);
 155         tm->tm_wday = bcd2bin(regs[ABEOZ9_REG_WEEKDAYS - ABEOZ9_REG_SEC]);
 156         tm->tm_mon  = bcd2bin(regs[ABEOZ9_REG_MONTHS - ABEOZ9_REG_SEC]) - 1;
 157         tm->tm_year = bcd2bin(regs[ABEOZ9_REG_YEARS - ABEOZ9_REG_SEC]) + 100;
 158
 159         return ret;
 160 }
 161
 162 static int abeoz9_rtc_set_time(struct device *dev, struct rtc_time *tm)
 163 {
 164         struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 165         struct regmap *regmap = data->regmap;
 166         u8 regs[ABEOZ9_SEC_LEN];
 167         int ret;
 168
 169         regs[ABEOZ9_REG_SEC - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_sec);
 170         regs[ABEOZ9_REG_MIN - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_min);
 171         regs[ABEOZ9_REG_HOURS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_hour);
 172         regs[ABEOZ9_REG_DAYS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_mday);
 173         regs[ABEOZ9_REG_WEEKDAYS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_wday);
 174         regs[ABEOZ9_REG_MONTHS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_mon + 1);
 175         regs[ABEOZ9_REG_YEARS - ABEOZ9_REG_SEC] = bin2bcd(tm->tm_year - 100);
 176
 177         ret = regmap_bulk_write(data->regmap, ABEOZ9_REG_SEC,
 178                                 regs,
 179                                 sizeof(regs));
 180
 181         if (ret) {
 182                 dev_err(dev, "set RTC time failed (%d)\n", ret);
 183                 return ret;
 184         }
 185
 186         return abeoz9_reset_validity(regmap);
 187 }
 188
 189 static int abeoz9_trickle_parse_dt(struct device_node *node)
 190 {
 191         u32 ohms = 0;
 192
 193         if (of_property_read_u32(node, "trickle-resistor-ohms", &ohms))
 194                 return 0;
 195
 196         switch (ohms) {
 197         case 1000:
 198                 return ABEOZ9_REG_EEPROM_R1K;
 199         case 5000:
 200                 return ABEOZ9_REG_EEPROM_R5K;
 201         case 20000:
 202                 return ABEOZ9_REG_EEPROM_R20K;
 203         case 80000:
 204                 return ABEOZ9_REG_EEPROM_R80K;
 205         default:
 206                 return 0;
 207         }
 208 }
 209
 210 static int abeoz9_rtc_setup(struct device *dev, struct device_node *node)
 211 {
 212         struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 213         struct regmap *regmap = data->regmap;
 214         int ret;
 215
 216         /* Enable Self Recovery, Clock for Watch and EEPROM refresh functions */
 217         ret = regmap_update_bits(regmap, ABEOZ9_REG_CTRL1,
 218                                  ABEOZ9_REG_CTRL1_MASK,
 219                                  ABEOZ9_REG_CTRL1_WE |
 220                                  ABEOZ9_REG_CTRL1_EERE |
 221                                  ABEOZ9_REG_CTRL1_SRON);
 222         if (ret < 0) {
 223                 dev_err(dev, "unable to set CTRL_1 register (%d)\n", ret);
 224                 return ret;
 225         }
 226
 227         ret = regmap_write(regmap, ABEOZ9_REG_CTRL_INT, 0);
 228         if (ret < 0) {
 229                 dev_err(dev,
 230                         "unable to set control CTRL_INT register (%d)\n",
 231                         ret);
 232                 return ret;
 233         }
 234
 235         ret = regmap_write(regmap, ABEOZ9_REG_CTRL_INT_FLAG, 0);
 236         if (ret < 0) {
 237                 dev_err(dev,
 238                         "unable to set control CTRL_INT_FLAG register (%d)\n",
 239                         ret);
 240                 return ret;
 241         }
 242
 243         ret = abeoz9_trickle_parse_dt(node);
 244
 245         /* Enable built-in termometer */
 246         ret |= ABEOZ9_REG_EEPROM_THE;
 247
 248         ret = regmap_update_bits(regmap, ABEOZ9_REG_EEPROM,
 249                                  ABEOZ9_REG_EEPROM_MASK,
 250                                  ret);
 251         if (ret < 0) {
 252                 dev_err(dev, "unable to set EEPROM register (%d)\n", ret);
 253                 return ret;
 254         }
 255
 256         return ret;
 257 }
 258
 259 static const struct rtc_class_ops rtc_ops = {
 260         .read_time = abeoz9_rtc_get_time,
 261         .set_time  = abeoz9_rtc_set_time,
 262 };
 263
 264 static const struct regmap_config abeoz9_rtc_regmap_config = {
 265         .reg_bits = 8,
 266         .val_bits = 8,
 267 };
 268
 269 #if IS_REACHABLE(CONFIG_HWMON)
 270
 271 static int abeoz9z3_temp_read(struct device *dev,
 272                               enum hwmon_sensor_types type,
 273                               u32 attr, int channel, long *temp)
 274 {
 275         struct abeoz9_rtc_data *data = dev_get_drvdata(dev);
 276         struct regmap *regmap = data->regmap;
 277         int ret;
 278         unsigned int val;
 279
 280         ret = regmap_read(regmap, ABEOZ9_REG_CTRL_STATUS, &val);
 281         if (ret < 0)
 282                 return ret;
 283
 284         if ((val & ABEOZ9_REG_CTRL_STATUS_V1F) ||
 285             (val & ABEOZ9_REG_CTRL_STATUS_V2F)) {
 286                 dev_err(dev,
 287                         "thermometer might be disabled due to low voltage\n");
 288                 return -EINVAL;
 289         }
 290
 291         switch (attr) {
 292         case hwmon_temp_input:
 293                 ret = regmap_read(regmap, ABEOZ9_REG_REG_TEMP, &val);
 294                 if (ret < 0)
 295                         return ret;
 296                 *temp = 1000 * (val + ABEOZ953_TEMP_MIN);
 297                 return 0;
 298         case hwmon_temp_max:
 299                 *temp = 1000 * ABEOZ953_TEMP_MAX;
 300                 return 0;
 301         case hwmon_temp_min:
 302                 *temp = 1000 * ABEOZ953_TEMP_MIN;
 303                 return 0;
 304         default:
 305                 return -EOPNOTSUPP;
 306         }
 307 }
 308
 309 static umode_t abeoz9_is_visible(const void *data,
 310                                  enum hwmon_sensor_types type,
 311                                  u32 attr, int channel)
 312 {
 313         switch (attr) {
 314         case hwmon_temp_input:
 315         case hwmon_temp_max:
 316         case hwmon_temp_min:
 317                 return 0444;
 318         default:
 319                 return 0;
 320         }
 321 }
 322
 323 static const u32 abeoz9_chip_config[] = {
 324         HWMON_C_REGISTER_TZ,
 325         0
 326 };
 327
 328 static const struct hwmon_channel_info abeoz9_chip = {
 329         .type = hwmon_chip,
 330         .config = abeoz9_chip_config,
 331 };
 332
 333 static const u32 abeoz9_temp_config[] = {
 334         HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN,
 335         0
 336 };
 337
 338 static const struct hwmon_channel_info abeoz9_temp = {
 339         .type = hwmon_temp,
 340         .config = abeoz9_temp_config,
 341 };
 342
 343 static const struct hwmon_channel_info *abeoz9_info[] = {
 344         &abeoz9_chip,
 345         &abeoz9_temp,
 346         NULL
 347 };
 348
 349 static const struct hwmon_ops abeoz9_hwmon_ops = {
 350         .is_visible = abeoz9_is_visible,
 351         .read = abeoz9z3_temp_read,
 352 };
 353
 354 static const struct hwmon_chip_info abeoz9_chip_info = {
 355         .ops = &abeoz9_hwmon_ops,
 356         .info = abeoz9_info,
 357 };
 358
 359 static void abeoz9_hwmon_register(struct device *dev,
 360                                   struct abeoz9_rtc_data *data)
 361 {
 362         data->hwmon_dev =
 363                 devm_hwmon_device_register_with_info(dev,
 364                                                      "abeoz9",
 365                                                      data,
 366                                                      &abeoz9_chip_info,
 367                                                      NULL);
 368         if (IS_ERR(data->hwmon_dev)) {
 369                 dev_warn(dev, "unable to register hwmon device %ld\n",
 370                          PTR_ERR(data->hwmon_dev));
 371         }
 372 }
 373
 374 #else
 375
 376 static void abeoz9_hwmon_register(struct device *dev,
 377                                   struct abeoz9_rtc_data *data)
 378 {
 379 }
 380
 381 #endif
 382
 383 static int abeoz9_probe(struct i2c_client *client,
 384                         const struct i2c_device_id *id)
 385 {
 386         struct abeoz9_rtc_data *data = NULL;
 387         struct device *dev = &client->dev;
 388         struct regmap *regmap;
 389         int ret;
 390
 391         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 392                                      I2C_FUNC_SMBUS_BYTE_DATA |
 393                                      I2C_FUNC_SMBUS_I2C_BLOCK))
 394                 return -ENODEV;
 395
 396         regmap = devm_regmap_init_i2c(client, &abeoz9_rtc_regmap_config);
 397         if (IS_ERR(regmap)) {
 398                 ret = PTR_ERR(regmap);
 399                 dev_err(dev, "regmap allocation failed: %d\n", ret);
 400                 return ret;
 401         }
 402
 403         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 404         if (!data)
 405                 return -ENOMEM;
 406
 407         data->regmap = regmap;
 408         dev_set_drvdata(dev, data);
 409
 410         ret = abeoz9_rtc_setup(dev, client->dev.of_node);
 411         if (ret)
 412                 return ret;
 413
 414         data->rtc = devm_rtc_allocate_device(dev);
 415         ret = PTR_ERR_OR_ZERO(data->rtc);
 416         if (ret)
 417                 return ret;
 418
 419         data->rtc->ops = &rtc_ops;
 420         data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 421         data->rtc->range_max = RTC_TIMESTAMP_END_2099;
 422
 423         ret = devm_rtc_register_device(data->rtc);
 424         if (ret)
 425                 return ret;
 426
 427         abeoz9_hwmon_register(dev, data);
 428         return 0;
 429 }
 430
 431 #ifdef CONFIG_OF
 432 static const struct of_device_id abeoz9_dt_match[] = {
 433         { .compatible = "abracon,abeoz9" },
 434         { },
 435 };
 436 MODULE_DEVICE_TABLE(of, abeoz9_dt_match);
 437 #endif
 438
 439 static const struct i2c_device_id abeoz9_id[] = {
 440         { "abeoz9", 0 },
 441         { }
 442 };
 443
 444 static struct i2c_driver abeoz9_driver = {
 445         .driver = {
 446                 .name = "rtc-ab-eoz9",
 447                 .of_match_table = of_match_ptr(abeoz9_dt_match),
 448         },
 449         .probe    = abeoz9_probe,
 450         .id_table = abeoz9_id,
 451 };
 452
 453 module_i2c_driver(abeoz9_driver);
 454
 455 MODULE_AUTHOR("Artem Panfilov <panfilov.artyom@gmail.com>");
 456 MODULE_DESCRIPTION("Abracon AB-RTCMC-32.768kHz-EOZ9 RTC driver");
 457 MODULE_LICENSE("GPL");