linux/drivers/rtc/rtc-ab-eoz9.c
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   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
  75struct abeoz9_rtc_data {
  76        struct rtc_device *rtc;
  77        struct regmap *regmap;
  78        struct device *hwmon_dev;
  79};
  80
  81static 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
 115static 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
 124static 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
 162static 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
 189static 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
 210static 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
 259static const struct rtc_class_ops rtc_ops = {
 260        .read_time = abeoz9_rtc_get_time,
 261        .set_time  = abeoz9_rtc_set_time,
 262};
 263
 264static 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
 271static 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
 309static 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
 323static const u32 abeoz9_chip_config[] = {
 324        HWMON_C_REGISTER_TZ,
 325        0
 326};
 327
 328static const struct hwmon_channel_info abeoz9_chip = {
 329        .type = hwmon_chip,
 330        .config = abeoz9_chip_config,
 331};
 332
 333static const u32 abeoz9_temp_config[] = {
 334        HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN,
 335        0
 336};
 337
 338static const struct hwmon_channel_info abeoz9_temp = {
 339        .type = hwmon_temp,
 340        .config = abeoz9_temp_config,
 341};
 342
 343static const struct hwmon_channel_info *abeoz9_info[] = {
 344        &abeoz9_chip,
 345        &abeoz9_temp,
 346        NULL
 347};
 348
 349static const struct hwmon_ops abeoz9_hwmon_ops = {
 350        .is_visible = abeoz9_is_visible,
 351        .read = abeoz9z3_temp_read,
 352};
 353
 354static const struct hwmon_chip_info abeoz9_chip_info = {
 355        .ops = &abeoz9_hwmon_ops,
 356        .info = abeoz9_info,
 357};
 358
 359static 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
 376static void abeoz9_hwmon_register(struct device *dev,
 377                                  struct abeoz9_rtc_data *data)
 378{
 379}
 380
 381#endif
 382
 383static 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                ret = -ENODEV;
 395                goto err;
 396        }
 397
 398        regmap = devm_regmap_init_i2c(client, &abeoz9_rtc_regmap_config);
 399        if (IS_ERR(regmap)) {
 400                ret = PTR_ERR(regmap);
 401                dev_err(dev, "regmap allocation failed: %d\n", ret);
 402                goto err;
 403        }
 404
 405        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 406        if (!data) {
 407                ret = -ENOMEM;
 408                goto err;
 409        }
 410
 411        data->regmap = regmap;
 412        dev_set_drvdata(dev, data);
 413
 414        ret = abeoz9_rtc_setup(dev, client->dev.of_node);
 415        if (ret)
 416                goto err;
 417
 418        data->rtc = devm_rtc_allocate_device(dev);
 419        ret = PTR_ERR_OR_ZERO(data->rtc);
 420        if (ret)
 421                goto err;
 422
 423        data->rtc->ops = &rtc_ops;
 424        data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 425        data->rtc->range_max = RTC_TIMESTAMP_END_2099;
 426
 427        ret = rtc_register_device(data->rtc);
 428        if (ret)
 429                goto err;
 430
 431        abeoz9_hwmon_register(dev, data);
 432        return 0;
 433
 434err:
 435        dev_err(dev, "unable to register RTC device (%d)\n", ret);
 436        return ret;
 437}
 438
 439#ifdef CONFIG_OF
 440static const struct of_device_id abeoz9_dt_match[] = {
 441        { .compatible = "abracon,abeoz9" },
 442        { },
 443};
 444MODULE_DEVICE_TABLE(of, abeoz9_dt_match);
 445#endif
 446
 447static const struct i2c_device_id abeoz9_id[] = {
 448        { "abeoz9", 0 },
 449        { }
 450};
 451
 452static struct i2c_driver abeoz9_driver = {
 453        .driver = {
 454                .name = "rtc-ab-eoz9",
 455                .of_match_table = of_match_ptr(abeoz9_dt_match),
 456        },
 457        .probe    = abeoz9_probe,
 458        .id_table = abeoz9_id,
 459};
 460
 461module_i2c_driver(abeoz9_driver);
 462
 463MODULE_AUTHOR("Artem Panfilov <panfilov.artyom@gmail.com>");
 464MODULE_DESCRIPTION("Abracon AB-RTCMC-32.768kHz-EOZ9 RTC driver");
 465MODULE_LICENSE("GPL");
 466