drivers/rtc/rtc-rx8111.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for Epson RX8111 RTC.
   4  *
   5  * Copyright (C) 2023 Axis Communications AB
   6  */
   7
   8 #include <linux/bcd.h>
   9 #include <linux/bitfield.h>
  10 #include <linux/i2c.h>
  11 #include <linux/module.h>
  12 #include <linux/regmap.h>
  13
  14 #include <linux/rtc.h>
  15
  16 #define RX8111_REG_SEC                  0x10    /* Second counter. */
  17 #define RX8111_REG_MIN                  0x11    /* Minute counter */
  18 #define RX8111_REG_HOUR                 0x12    /* Hour counter. */
  19 #define RX8111_REG_WEEK                 0x13    /* Week day counter. */
  20 #define RX8111_REG_DAY                  0x14    /* Month day counter. */
  21 #define RX8111_REG_MONTH                0x15    /* Month counter. */
  22 #define RX8111_REG_YEAR                 0x16    /* Year counter. */
  23
  24 #define RX8111_REG_ALARM_MIN            0x17    /* Alarm minute. */
  25 #define RX8111_REG_ALARM_HOUR           0x18    /* Alarm hour. */
  26 #define RX8111_REG_ALARM_WEEK_DAY       0x19    /* Alarm week or month day. */
  27
  28 #define RX8111_REG_TIMER_COUNTER0       0x1a    /* Timer counter LSB. */
  29 #define RX8111_REG_TIMER_COUNTER1       0x1b    /* Timer counter. */
  30 #define RX8111_REG_TIMER_COUNTER2       0x1c    /* Timer counter MSB. */
  31
  32 #define RX8111_REG_EXT                  0x1d    /* Extension register. */
  33 #define RX8111_REG_FLAG                 0x1e    /* Flag register. */
  34 #define RX8111_REG_CTRL                 0x1f    /* Control register. */
  35
  36 #define RX8111_REG_TS_1_1000_SEC        0x20    /* Timestamp 256 or 512 Hz . */
  37 #define RX8111_REG_TS_1_100_SEC         0x21    /* Timestamp 1 - 128 Hz. */
  38 #define RX8111_REG_TS_SEC               0x22    /* Timestamp second. */
  39 #define RX8111_REG_TS_MIN               0x23    /* Timestamp minute. */
  40 #define RX8111_REG_TS_HOUR              0x24    /* Timestamp hour. */
  41 #define RX8111_REG_TS_WEEK              0x25    /* Timestamp week day. */
  42 #define RX8111_REG_TS_DAY               0x26    /* Timestamp month day. */
  43 #define RX8111_REG_TS_MONTH             0x27    /* Timestamp month. */
  44 #define RX8111_REG_TS_YEAR              0x28    /* Timestamp year. */
  45 #define RX8111_REG_TS_STATUS            0x29    /* Timestamp status. */
  46
  47 #define RX8111_REG_EVIN_SETTING         0x2b    /* Timestamp trigger setting. */
  48 #define RX8111_REG_ALARM_SEC            0x2c    /* Alarm second. */
  49 #define RX8111_REG_TIMER_CTRL           0x2d    /* Timer control. */
  50 #define RX8111_REG_TS_CTRL0             0x2e    /* Timestamp control 0. */
  51 #define RX8111_REG_CMD_TRIGGER          0x2f    /* Timestamp trigger. */
  52 #define RX8111_REG_PWR_SWITCH_CTRL      0x32    /* Power switch control. */
  53 #define RX8111_REG_STATUS_MON           0x33    /* Status monitor. */
  54 #define RX8111_REG_TS_CTRL1             0x34    /* Timestamp control 1. */
  55 #define RX8111_REG_TS_CTRL2             0x35    /* Timestamp control 2. */
  56 #define RX8111_REG_TS_CTRL3             0x36    /* Timestamp control 3. */
  57
  58 #define RX8111_FLAG_XST_BIT BIT(0)
  59 #define RX8111_FLAG_VLF_BIT BIT(1)
  60
  61 #define RX8111_TIME_BUF_SZ (RX8111_REG_YEAR - RX8111_REG_SEC + 1)
  62
  63 enum rx8111_regfield {
  64         /* RX8111_REG_EXT. */
  65         RX8111_REGF_TSEL0,
  66         RX8111_REGF_TSEL1,
  67         RX8111_REGF_ETS,
  68         RX8111_REGF_WADA,
  69         RX8111_REGF_TE,
  70         RX8111_REGF_USEL,
  71         RX8111_REGF_FSEL0,
  72         RX8111_REGF_FSEL1,
  73
  74         /* RX8111_REG_FLAG. */
  75         RX8111_REGF_XST,
  76         RX8111_REGF_VLF,
  77         RX8111_REGF_EVF,
  78         RX8111_REGF_AF,
  79         RX8111_REGF_TF,
  80         RX8111_REGF_UF,
  81         RX8111_REGF_POR,
  82
  83         /* RX8111_REG_CTRL. */
  84         RX8111_REGF_STOP,
  85         RX8111_REGF_EIE,
  86         RX8111_REGF_AIE,
  87         RX8111_REGF_TIE,
  88         RX8111_REGF_UIE,
  89
  90         /* RX8111_REG_PWR_SWITCH_CTRL. */
  91         RX8111_REGF_SMPT0,
  92         RX8111_REGF_SMPT1,
  93         RX8111_REGF_SWSEL0,
  94         RX8111_REGF_SWSEL1,
  95         RX8111_REGF_INIEN,
  96         RX8111_REGF_CHGEN,
  97
  98         /* RX8111_REG_STATUS_MON. */
  99         RX8111_REGF_VLOW,
 100
 101         /* Sentinel value. */
 102         RX8111_REGF_MAX
 103 };
 104
 105 static const struct reg_field rx8111_regfields[] = {
 106         [RX8111_REGF_TSEL0] = REG_FIELD(RX8111_REG_EXT, 0, 0),
 107         [RX8111_REGF_TSEL1] = REG_FIELD(RX8111_REG_EXT, 1, 1),
 108         [RX8111_REGF_ETS]   = REG_FIELD(RX8111_REG_EXT, 2, 2),
 109         [RX8111_REGF_WADA]  = REG_FIELD(RX8111_REG_EXT, 3, 3),
 110         [RX8111_REGF_TE]    = REG_FIELD(RX8111_REG_EXT, 4, 4),
 111         [RX8111_REGF_USEL]  = REG_FIELD(RX8111_REG_EXT, 5, 5),
 112         [RX8111_REGF_FSEL0] = REG_FIELD(RX8111_REG_EXT, 6, 6),
 113         [RX8111_REGF_FSEL1] = REG_FIELD(RX8111_REG_EXT, 7, 7),
 114
 115         [RX8111_REGF_XST] = REG_FIELD(RX8111_REG_FLAG, 0, 0),
 116         [RX8111_REGF_VLF] = REG_FIELD(RX8111_REG_FLAG, 1, 1),
 117         [RX8111_REGF_EVF] = REG_FIELD(RX8111_REG_FLAG, 2, 2),
 118         [RX8111_REGF_AF]  = REG_FIELD(RX8111_REG_FLAG, 3, 3),
 119         [RX8111_REGF_TF]  = REG_FIELD(RX8111_REG_FLAG, 4, 4),
 120         [RX8111_REGF_UF]  = REG_FIELD(RX8111_REG_FLAG, 5, 5),
 121         [RX8111_REGF_POR] = REG_FIELD(RX8111_REG_FLAG, 7, 7),
 122
 123         [RX8111_REGF_STOP] = REG_FIELD(RX8111_REG_CTRL, 0, 0),
 124         [RX8111_REGF_EIE]  = REG_FIELD(RX8111_REG_CTRL, 2, 2),
 125         [RX8111_REGF_AIE]  = REG_FIELD(RX8111_REG_CTRL, 3, 3),
 126         [RX8111_REGF_TIE]  = REG_FIELD(RX8111_REG_CTRL, 4, 4),
 127         [RX8111_REGF_UIE]  = REG_FIELD(RX8111_REG_CTRL, 5, 5),
 128
 129         [RX8111_REGF_SMPT0]  = REG_FIELD(RX8111_REG_PWR_SWITCH_CTRL, 0, 0),
 130         [RX8111_REGF_SMPT1]  = REG_FIELD(RX8111_REG_PWR_SWITCH_CTRL, 1, 1),
 131         [RX8111_REGF_SWSEL0] = REG_FIELD(RX8111_REG_PWR_SWITCH_CTRL, 2, 2),
 132         [RX8111_REGF_SWSEL1] = REG_FIELD(RX8111_REG_PWR_SWITCH_CTRL, 3, 3),
 133         [RX8111_REGF_INIEN]  = REG_FIELD(RX8111_REG_PWR_SWITCH_CTRL, 6, 6),
 134         [RX8111_REGF_CHGEN]  = REG_FIELD(RX8111_REG_PWR_SWITCH_CTRL, 7, 7),
 135
 136         [RX8111_REGF_VLOW]  = REG_FIELD(RX8111_REG_STATUS_MON, 1, 1),
 137 };
 138
 139 static const struct regmap_config rx8111_regmap_config = {
 140         .reg_bits = 8,
 141         .val_bits = 8,
 142         .max_register = RX8111_REG_TS_CTRL3,
 143 };
 144
 145 struct rx8111_data {
 146         struct regmap *regmap;
 147         struct regmap_field *regfields[RX8111_REGF_MAX];
 148         struct device *dev;
 149         struct rtc_device *rtc;
 150 };
 151
 152 static int rx8111_read_vl_flag(struct rx8111_data *data, unsigned int *vlval)
 153 {
 154         int ret;
 155
 156         ret = regmap_field_read(data->regfields[RX8111_REGF_VLF], vlval);
 157         if (ret)
 158                 dev_dbg(data->dev, "Could not read VL flag (%d)", ret);
 159
 160         return ret;
 161 }
 162
 163 static int rx8111_read_time(struct device *dev, struct rtc_time *tm)
 164 {
 165         struct rx8111_data *data = dev_get_drvdata(dev);
 166         u8 buf[RX8111_TIME_BUF_SZ];
 167         unsigned int regval;
 168         int ret;
 169
 170         /* Check status. */
 171         ret = regmap_read(data->regmap, RX8111_REG_FLAG, &regval);
 172         if (ret) {
 173                 dev_dbg(data->dev, "Could not read flag register (%d)\n", ret);
 174                 return ret;
 175         }
 176
 177         if (FIELD_GET(RX8111_FLAG_XST_BIT, regval)) {
 178                 dev_dbg(data->dev,
 179                         "Crystal oscillation stopped, time is not reliable\n");
 180                 return -EINVAL;
 181         }
 182
 183         if (FIELD_GET(RX8111_FLAG_VLF_BIT, regval)) {
 184                 dev_dbg(data->dev,
 185                         "Low voltage detected, time is not reliable\n");
 186                 return -EINVAL;
 187         }
 188
 189         ret = regmap_field_read(data->regfields[RX8111_REGF_STOP], &regval);
 190         if (ret) {
 191                 dev_dbg(data->dev, "Could not read clock status (%d)\n", ret);
 192                 return ret;
 193         }
 194
 195         if (regval) {
 196                 dev_dbg(data->dev, "Clock stopped, time is not reliable\n");
 197                 return -EINVAL;
 198         }
 199
 200         /* Read time. */
 201         ret = regmap_bulk_read(data->regmap, RX8111_REG_SEC, buf,
 202                                ARRAY_SIZE(buf));
 203         if (ret) {
 204                 dev_dbg(data->dev, "Could not bulk read time (%d)\n", ret);
 205                 return ret;
 206         }
 207
 208         tm->tm_sec = bcd2bin(buf[0]);
 209         tm->tm_min = bcd2bin(buf[1]);
 210         tm->tm_hour = bcd2bin(buf[2]);
 211         tm->tm_wday = ffs(buf[3]) - 1;
 212         tm->tm_mday = bcd2bin(buf[4]);
 213         tm->tm_mon = bcd2bin(buf[5]) - 1;
 214         tm->tm_year = bcd2bin(buf[6]) + 100;
 215
 216         return 0;
 217 }
 218
 219 static int rx8111_set_time(struct device *dev, struct rtc_time *tm)
 220 {
 221         struct rx8111_data *data = dev_get_drvdata(dev);
 222         u8 buf[RX8111_TIME_BUF_SZ];
 223         int ret;
 224
 225         buf[0] = bin2bcd(tm->tm_sec);
 226         buf[1] = bin2bcd(tm->tm_min);
 227         buf[2] = bin2bcd(tm->tm_hour);
 228         buf[3] = BIT(tm->tm_wday);
 229         buf[4] = bin2bcd(tm->tm_mday);
 230         buf[5] = bin2bcd(tm->tm_mon + 1);
 231         buf[6] = bin2bcd(tm->tm_year - 100);
 232
 233         ret = regmap_clear_bits(data->regmap, RX8111_REG_FLAG,
 234                                 RX8111_FLAG_XST_BIT | RX8111_FLAG_VLF_BIT);
 235         if (ret)
 236                 return ret;
 237
 238         /* Stop the clock. */
 239         ret = regmap_field_write(data->regfields[RX8111_REGF_STOP], 1);
 240         if (ret) {
 241                 dev_dbg(data->dev, "Could not stop the clock (%d)\n", ret);
 242                 return ret;
 243         }
 244
 245         /* Set the time. */
 246         ret = regmap_bulk_write(data->regmap, RX8111_REG_SEC, buf,
 247                                 ARRAY_SIZE(buf));
 248         if (ret) {
 249                 dev_dbg(data->dev, "Could not bulk write time (%d)\n", ret);
 250
 251                 /*
 252                  * We don't bother with trying to start the clock again. We
 253                  * check for this in rx8111_read_time() (and thus force user to
 254                  * call rx8111_set_time() to try again).
 255                  */
 256                 return ret;
 257         }
 258
 259         /* Start the clock. */
 260         ret = regmap_field_write(data->regfields[RX8111_REGF_STOP], 0);
 261         if (ret) {
 262                 dev_dbg(data->dev, "Could not start the clock (%d)\n", ret);
 263                 return ret;
 264         }
 265
 266         return 0;
 267 }
 268
 269 static int rx8111_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 270 {
 271         struct rx8111_data *data = dev_get_drvdata(dev);
 272         unsigned int regval;
 273         unsigned int vlval;
 274         int ret;
 275
 276         switch (cmd) {
 277         case RTC_VL_READ:
 278                 ret = rx8111_read_vl_flag(data, &regval);
 279                 if (ret)
 280                         return ret;
 281
 282                 vlval = regval ? RTC_VL_DATA_INVALID : 0;
 283
 284                 ret = regmap_field_read(data->regfields[RX8111_REGF_VLOW],
 285                                         &regval);
 286                 if (ret)
 287                         return ret;
 288
 289                 vlval |= regval ? RTC_VL_BACKUP_LOW : 0;
 290
 291                 return put_user(vlval, (typeof(vlval) __user *)arg);
 292         default:
 293                 return -ENOIOCTLCMD;
 294         }
 295 }
 296
 297 static const struct rtc_class_ops rx8111_rtc_ops = {
 298         .read_time = rx8111_read_time,
 299         .set_time = rx8111_set_time,
 300         .ioctl = rx8111_ioctl,
 301 };
 302
 303 static int rx8111_probe(struct i2c_client *client)
 304 {
 305         struct rx8111_data *data;
 306         struct rtc_device *rtc;
 307         size_t i;
 308
 309         data = devm_kmalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 310         if (!data) {
 311                 dev_dbg(&client->dev, "Could not allocate device data\n");
 312                 return -ENOMEM;
 313         }
 314
 315         data->dev = &client->dev;
 316         dev_set_drvdata(data->dev, data);
 317
 318         data->regmap = devm_regmap_init_i2c(client, &rx8111_regmap_config);
 319         if (IS_ERR(data->regmap)) {
 320                 dev_dbg(data->dev, "Could not initialize regmap\n");
 321                 return PTR_ERR(data->regmap);
 322         }
 323
 324         for (i = 0; i < RX8111_REGF_MAX; ++i) {
 325                 data->regfields[i] = devm_regmap_field_alloc(
 326                         data->dev, data->regmap, rx8111_regfields[i]);
 327                 if (IS_ERR(data->regfields[i])) {
 328                         dev_dbg(data->dev,
 329                                 "Could not allocate register field %zu\n", i);
 330                         return PTR_ERR(data->regfields[i]);
 331                 }
 332         }
 333
 334         rtc = devm_rtc_allocate_device(data->dev);
 335         if (IS_ERR(rtc)) {
 336                 dev_dbg(data->dev, "Could not allocate rtc device\n");
 337                 return PTR_ERR(rtc);
 338         }
 339
 340         rtc->ops = &rx8111_rtc_ops;
 341         rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 342         rtc->range_max = RTC_TIMESTAMP_END_2099;
 343
 344         clear_bit(RTC_FEATURE_ALARM, rtc->features);
 345
 346         return devm_rtc_register_device(rtc);
 347 }
 348
 349 static const struct of_device_id rx8111_of_match[] = {
 350         {
 351                 .compatible = "epson,rx8111",
 352         },
 353         {}
 354 };
 355 MODULE_DEVICE_TABLE(of, rx8111_of_match);
 356
 357 static struct i2c_driver rx8111_driver = {
 358         .driver = {
 359                 .name = "rtc-rx8111",
 360                 .of_match_table = rx8111_of_match,
 361         },
 362         .probe = rx8111_probe,
 363 };
 364 module_i2c_driver(rx8111_driver);
 365
 366 MODULE_AUTHOR("Waqar Hameed <waqar.hameed@axis.com>");
 367 MODULE_DESCRIPTION("Epson RX8111 RTC driver");
 368 MODULE_LICENSE("GPL");