drivers/rtc/rtc-rx6110.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for the Epson RTC module RX-6110 SA
   4  *
   5  * Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
   6  * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
   7  */
   8
   9 #include <linux/bcd.h>
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/of_gpio.h>
  14 #include <linux/regmap.h>
  15 #include <linux/rtc.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/spi/spi.h>
  19 #include <linux/i2c.h>
  20
  21 /* RX-6110 Register definitions */
  22 #define RX6110_REG_SEC          0x10
  23 #define RX6110_REG_MIN          0x11
  24 #define RX6110_REG_HOUR         0x12
  25 #define RX6110_REG_WDAY         0x13
  26 #define RX6110_REG_MDAY         0x14
  27 #define RX6110_REG_MONTH        0x15
  28 #define RX6110_REG_YEAR         0x16
  29 #define RX6110_REG_RES1         0x17
  30 #define RX6110_REG_ALMIN        0x18
  31 #define RX6110_REG_ALHOUR       0x19
  32 #define RX6110_REG_ALWDAY       0x1A
  33 #define RX6110_REG_TCOUNT0      0x1B
  34 #define RX6110_REG_TCOUNT1      0x1C
  35 #define RX6110_REG_EXT          0x1D
  36 #define RX6110_REG_FLAG         0x1E
  37 #define RX6110_REG_CTRL         0x1F
  38 #define RX6110_REG_USER0        0x20
  39 #define RX6110_REG_USER1        0x21
  40 #define RX6110_REG_USER2        0x22
  41 #define RX6110_REG_USER3        0x23
  42 #define RX6110_REG_USER4        0x24
  43 #define RX6110_REG_USER5        0x25
  44 #define RX6110_REG_USER6        0x26
  45 #define RX6110_REG_USER7        0x27
  46 #define RX6110_REG_USER8        0x28
  47 #define RX6110_REG_USER9        0x29
  48 #define RX6110_REG_USERA        0x2A
  49 #define RX6110_REG_USERB        0x2B
  50 #define RX6110_REG_USERC        0x2C
  51 #define RX6110_REG_USERD        0x2D
  52 #define RX6110_REG_USERE        0x2E
  53 #define RX6110_REG_USERF        0x2F
  54 #define RX6110_REG_RES2         0x30
  55 #define RX6110_REG_RES3         0x31
  56 #define RX6110_REG_IRQ          0x32
  57
  58 #define RX6110_BIT_ALARM_EN             BIT(7)
  59
  60 /* Extension Register (1Dh) bit positions */
  61 #define RX6110_BIT_EXT_TSEL0            BIT(0)
  62 #define RX6110_BIT_EXT_TSEL1            BIT(1)
  63 #define RX6110_BIT_EXT_TSEL2            BIT(2)
  64 #define RX6110_BIT_EXT_WADA             BIT(3)
  65 #define RX6110_BIT_EXT_TE               BIT(4)
  66 #define RX6110_BIT_EXT_USEL             BIT(5)
  67 #define RX6110_BIT_EXT_FSEL0            BIT(6)
  68 #define RX6110_BIT_EXT_FSEL1            BIT(7)
  69
  70 /* Flag Register (1Eh) bit positions */
  71 #define RX6110_BIT_FLAG_VLF             BIT(1)
  72 #define RX6110_BIT_FLAG_AF              BIT(3)
  73 #define RX6110_BIT_FLAG_TF              BIT(4)
  74 #define RX6110_BIT_FLAG_UF              BIT(5)
  75
  76 /* Control Register (1Fh) bit positions */
  77 #define RX6110_BIT_CTRL_TBKE            BIT(0)
  78 #define RX6110_BIT_CTRL_TBKON           BIT(1)
  79 #define RX6110_BIT_CTRL_TSTP            BIT(2)
  80 #define RX6110_BIT_CTRL_AIE             BIT(3)
  81 #define RX6110_BIT_CTRL_TIE             BIT(4)
  82 #define RX6110_BIT_CTRL_UIE             BIT(5)
  83 #define RX6110_BIT_CTRL_STOP            BIT(6)
  84 #define RX6110_BIT_CTRL_TEST            BIT(7)
  85
  86 enum {
  87         RTC_SEC = 0,
  88         RTC_MIN,
  89         RTC_HOUR,
  90         RTC_WDAY,
  91         RTC_MDAY,
  92         RTC_MONTH,
  93         RTC_YEAR,
  94         RTC_NR_TIME
  95 };
  96
  97 #define RX6110_DRIVER_NAME              "rx6110"
  98
  99 struct rx6110_data {
 100         struct rtc_device *rtc;
 101         struct regmap *regmap;
 102 };
 103
 104 /**
 105  * rx6110_rtc_tm_to_data - convert rtc_time to native time encoding
 106  *
 107  * @tm: holds date and time
 108  * @data: holds the encoding in rx6110 native form
 109  */
 110 static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
 111 {
 112         pr_debug("%s: date %ptRr\n", __func__, tm);
 113
 114         /*
 115          * The year in the RTC is a value between 0 and 99.
 116          * Assume that this represents the current century
 117          * and disregard all other values.
 118          */
 119         if (tm->tm_year < 100 || tm->tm_year >= 200)
 120                 return -EINVAL;
 121
 122         data[RTC_SEC] = bin2bcd(tm->tm_sec);
 123         data[RTC_MIN] = bin2bcd(tm->tm_min);
 124         data[RTC_HOUR] = bin2bcd(tm->tm_hour);
 125         data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday));
 126         data[RTC_MDAY] = bin2bcd(tm->tm_mday);
 127         data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
 128         data[RTC_YEAR] = bin2bcd(tm->tm_year % 100);
 129
 130         return 0;
 131 }
 132
 133 /**
 134  * rx6110_data_to_rtc_tm - convert native time encoding to rtc_time
 135  *
 136  * @data: holds the encoding in rx6110 native form
 137  * @tm: holds date and time
 138  */
 139 static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm)
 140 {
 141         tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f);
 142         tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f);
 143         /* only 24-hour clock */
 144         tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
 145         tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f);
 146         tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f);
 147         tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1;
 148         tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100;
 149
 150         pr_debug("%s: date %ptRr\n", __func__, tm);
 151
 152         /*
 153          * The year in the RTC is a value between 0 and 99.
 154          * Assume that this represents the current century
 155          * and disregard all other values.
 156          */
 157         if (tm->tm_year < 100 || tm->tm_year >= 200)
 158                 return -EINVAL;
 159
 160         return 0;
 161 }
 162
 163 /**
 164  * rx6110_set_time - set the current time in the rx6110 registers
 165  *
 166  * @dev: the rtc device in use
 167  * @tm: holds date and time
 168  *
 169  * BUG: The HW assumes every year that is a multiple of 4 to be a leap
 170  * year. Next time this is wrong is 2100, which will not be a leap year
 171  *
 172  * Note: If STOP is not set/cleared, the clock will start when the seconds
 173  *       register is written
 174  *
 175  */
 176 static int rx6110_set_time(struct device *dev, struct rtc_time *tm)
 177 {
 178         struct rx6110_data *rx6110 = dev_get_drvdata(dev);
 179         u8 data[RTC_NR_TIME];
 180         int ret;
 181
 182         ret = rx6110_rtc_tm_to_data(tm, data);
 183         if (ret < 0)
 184                 return ret;
 185
 186         /* set STOP bit before changing clock/calendar */
 187         ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
 188                                  RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP);
 189         if (ret)
 190                 return ret;
 191
 192         ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data,
 193                                 RTC_NR_TIME);
 194         if (ret)
 195                 return ret;
 196
 197         /* The time in the RTC is valid. Be sure to have VLF cleared. */
 198         ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
 199                                  RX6110_BIT_FLAG_VLF, 0);
 200         if (ret)
 201                 return ret;
 202
 203         /* clear STOP bit after changing clock/calendar */
 204         ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
 205                                  RX6110_BIT_CTRL_STOP, 0);
 206
 207         return ret;
 208 }
 209
 210 /**
 211  * rx6110_get_time - get the current time from the rx6110 registers
 212  * @dev: the rtc device in use
 213  * @tm: holds date and time
 214  */
 215 static int rx6110_get_time(struct device *dev, struct rtc_time *tm)
 216 {
 217         struct rx6110_data *rx6110 = dev_get_drvdata(dev);
 218         u8 data[RTC_NR_TIME];
 219         int flags;
 220         int ret;
 221
 222         ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
 223         if (ret)
 224                 return -EINVAL;
 225
 226         /* check for VLF Flag (set at power-on) */
 227         if ((flags & RX6110_BIT_FLAG_VLF)) {
 228                 dev_warn(dev, "Voltage low, data is invalid.\n");
 229                 return -EINVAL;
 230         }
 231
 232         /* read registers to date */
 233         ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data,
 234                                RTC_NR_TIME);
 235         if (ret)
 236                 return ret;
 237
 238         ret = rx6110_data_to_rtc_tm(data, tm);
 239         if (ret)
 240                 return ret;
 241
 242         dev_dbg(dev, "%s: date %ptRr\n", __func__, tm);
 243
 244         return 0;
 245 }
 246
 247 static const struct reg_sequence rx6110_default_regs[] = {
 248         { RX6110_REG_RES1,   0xB8 },
 249         { RX6110_REG_RES2,   0x00 },
 250         { RX6110_REG_RES3,   0x10 },
 251         { RX6110_REG_IRQ,    0x00 },
 252         { RX6110_REG_ALMIN,  0x00 },
 253         { RX6110_REG_ALHOUR, 0x00 },
 254         { RX6110_REG_ALWDAY, 0x00 },
 255 };
 256
 257 /**
 258  * rx6110_init - initialize the rx6110 registers
 259  *
 260  * @rx6110: pointer to the rx6110 struct in use
 261  *
 262  */
 263 static int rx6110_init(struct rx6110_data *rx6110)
 264 {
 265         struct rtc_device *rtc = rx6110->rtc;
 266         int flags;
 267         int ret;
 268
 269         ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT,
 270                                  RX6110_BIT_EXT_TE, 0);
 271         if (ret)
 272                 return ret;
 273
 274         ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs,
 275                                     ARRAY_SIZE(rx6110_default_regs));
 276         if (ret)
 277                 return ret;
 278
 279         ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
 280         if (ret)
 281                 return ret;
 282
 283         /* check for VLF Flag (set at power-on) */
 284         if ((flags & RX6110_BIT_FLAG_VLF))
 285                 dev_warn(&rtc->dev, "Voltage low, data loss detected.\n");
 286
 287         /* check for Alarm Flag */
 288         if (flags & RX6110_BIT_FLAG_AF)
 289                 dev_warn(&rtc->dev, "An alarm may have been missed.\n");
 290
 291         /* check for Periodic Timer Flag */
 292         if (flags & RX6110_BIT_FLAG_TF)
 293                 dev_warn(&rtc->dev, "Periodic timer was detected\n");
 294
 295         /* check for Update Timer Flag */
 296         if (flags & RX6110_BIT_FLAG_UF)
 297                 dev_warn(&rtc->dev, "Update timer was detected\n");
 298
 299         /* clear all flags BUT VLF */
 300         ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
 301                                  RX6110_BIT_FLAG_AF |
 302                                  RX6110_BIT_FLAG_UF |
 303                                  RX6110_BIT_FLAG_TF,
 304                                  0);
 305
 306         return ret;
 307 }
 308
 309 static const struct rtc_class_ops rx6110_rtc_ops = {
 310         .read_time = rx6110_get_time,
 311         .set_time = rx6110_set_time,
 312 };
 313
 314 static int rx6110_probe(struct rx6110_data *rx6110, struct device *dev)
 315 {
 316         int err;
 317
 318         rx6110->rtc = devm_rtc_device_register(dev,
 319                                                RX6110_DRIVER_NAME,
 320                                                &rx6110_rtc_ops, THIS_MODULE);
 321
 322         if (IS_ERR(rx6110->rtc))
 323                 return PTR_ERR(rx6110->rtc);
 324
 325         err = rx6110_init(rx6110);
 326         if (err)
 327                 return err;
 328
 329         rx6110->rtc->max_user_freq = 1;
 330
 331         return 0;
 332 }
 333
 334 #ifdef CONFIG_SPI_MASTER
 335 static struct regmap_config regmap_spi_config = {
 336         .reg_bits = 8,
 337         .val_bits = 8,
 338         .max_register = RX6110_REG_IRQ,
 339         .read_flag_mask = 0x80,
 340 };
 341
 342 /**
 343  * rx6110_spi_probe - initialize rtc driver
 344  * @spi: pointer to spi device
 345  */
 346 static int rx6110_spi_probe(struct spi_device *spi)
 347 {
 348         struct rx6110_data *rx6110;
 349
 350         if ((spi->bits_per_word && spi->bits_per_word != 8) ||
 351             (spi->max_speed_hz > 2000000) ||
 352             (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) {
 353                 dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n",
 354                          spi->bits_per_word, spi->max_speed_hz, spi->mode);
 355                 dev_warn(&spi->dev, "driving device in an unsupported mode");
 356         }
 357
 358         rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL);
 359         if (!rx6110)
 360                 return -ENOMEM;
 361
 362         rx6110->regmap = devm_regmap_init_spi(spi, &regmap_spi_config);
 363         if (IS_ERR(rx6110->regmap)) {
 364                 dev_err(&spi->dev, "regmap init failed for rtc rx6110\n");
 365                 return PTR_ERR(rx6110->regmap);
 366         }
 367
 368         spi_set_drvdata(spi, rx6110);
 369
 370         return rx6110_probe(rx6110, &spi->dev);
 371 }
 372
 373 static const struct spi_device_id rx6110_spi_id[] = {
 374         { "rx6110", 0 },
 375         { }
 376 };
 377 MODULE_DEVICE_TABLE(spi, rx6110_spi_id);
 378
 379 static const struct of_device_id rx6110_spi_of_match[] = {
 380         { .compatible = "epson,rx6110" },
 381         { },
 382 };
 383 MODULE_DEVICE_TABLE(of, rx6110_spi_of_match);
 384
 385 static struct spi_driver rx6110_spi_driver = {
 386         .driver = {
 387                 .name = RX6110_DRIVER_NAME,
 388                 .of_match_table = of_match_ptr(rx6110_spi_of_match),
 389         },
 390         .probe          = rx6110_spi_probe,
 391         .id_table       = rx6110_spi_id,
 392 };
 393
 394 static int rx6110_spi_register(void)
 395 {
 396         return spi_register_driver(&rx6110_spi_driver);
 397 }
 398
 399 static void rx6110_spi_unregister(void)
 400 {
 401         spi_unregister_driver(&rx6110_spi_driver);
 402 }
 403 #else
 404 static int rx6110_spi_register(void)
 405 {
 406         return 0;
 407 }
 408
 409 static void rx6110_spi_unregister(void)
 410 {
 411 }
 412 #endif /* CONFIG_SPI_MASTER */
 413
 414 #ifdef CONFIG_I2C
 415 static struct regmap_config regmap_i2c_config = {
 416         .reg_bits = 8,
 417         .val_bits = 8,
 418         .max_register = RX6110_REG_IRQ,
 419         .read_flag_mask = 0x80,
 420 };
 421
 422 static int rx6110_i2c_probe(struct i2c_client *client,
 423                             const struct i2c_device_id *id)
 424 {
 425         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 426         struct rx6110_data *rx6110;
 427
 428         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 429                                 | I2C_FUNC_SMBUS_I2C_BLOCK)) {
 430                 dev_err(&adapter->dev,
 431                         "doesn't support required functionality\n");
 432                 return -EIO;
 433         }
 434
 435         rx6110 = devm_kzalloc(&client->dev, sizeof(*rx6110), GFP_KERNEL);
 436         if (!rx6110)
 437                 return -ENOMEM;
 438
 439         rx6110->regmap = devm_regmap_init_i2c(client, &regmap_i2c_config);
 440         if (IS_ERR(rx6110->regmap)) {
 441                 dev_err(&client->dev, "regmap init failed for rtc rx6110\n");
 442                 return PTR_ERR(rx6110->regmap);
 443         }
 444
 445         i2c_set_clientdata(client, rx6110);
 446
 447         return rx6110_probe(rx6110, &client->dev);
 448 }
 449
 450 static const struct i2c_device_id rx6110_i2c_id[] = {
 451         { "rx6110", 0 },
 452         { }
 453 };
 454 MODULE_DEVICE_TABLE(i2c, rx6110_i2c_id);
 455
 456 static struct i2c_driver rx6110_i2c_driver = {
 457         .driver = {
 458                 .name = RX6110_DRIVER_NAME,
 459         },
 460         .probe          = rx6110_i2c_probe,
 461         .id_table       = rx6110_i2c_id,
 462 };
 463
 464 static int rx6110_i2c_register(void)
 465 {
 466         return i2c_add_driver(&rx6110_i2c_driver);
 467 }
 468
 469 static void rx6110_i2c_unregister(void)
 470 {
 471         i2c_del_driver(&rx6110_i2c_driver);
 472 }
 473 #else
 474 static int rx6110_i2c_register(void)
 475 {
 476         return 0;
 477 }
 478
 479 static void rx6110_i2c_unregister(void)
 480 {
 481 }
 482 #endif /* CONFIG_I2C */
 483
 484 static int __init rx6110_module_init(void)
 485 {
 486         int ret;
 487
 488         ret = rx6110_spi_register();
 489         if (ret)
 490                 return ret;
 491
 492         ret = rx6110_i2c_register();
 493         if (ret)
 494                 rx6110_spi_unregister();
 495
 496         return ret;
 497 }
 498 module_init(rx6110_module_init);
 499
 500 static void __exit rx6110_module_exit(void)
 501 {
 502         rx6110_spi_unregister();
 503         rx6110_i2c_unregister();
 504 }
 505 module_exit(rx6110_module_exit);
 506
 507 MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
 508 MODULE_DESCRIPTION("RX-6110 SA RTC driver");
 509 MODULE_LICENSE("GPL");