linux/drivers/rtc/rtc-rx6110.c
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   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
  86enum {
  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
  99struct 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 */
 110static 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 */
 139static 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 */
 176static 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 */
 215static 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
 247static 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 */
 263static 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
 309static const struct rtc_class_ops rx6110_rtc_ops = {
 310        .read_time = rx6110_get_time,
 311        .set_time = rx6110_set_time,
 312};
 313
 314static 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#if IS_ENABLED(CONFIG_SPI_MASTER)
 335static 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 */
 346static 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
 373static const struct spi_device_id rx6110_spi_id[] = {
 374        { "rx6110", 0 },
 375        { }
 376};
 377MODULE_DEVICE_TABLE(spi, rx6110_spi_id);
 378
 379static const struct of_device_id rx6110_spi_of_match[] = {
 380        { .compatible = "epson,rx6110" },
 381        { },
 382};
 383MODULE_DEVICE_TABLE(of, rx6110_spi_of_match);
 384
 385static 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
 394static int rx6110_spi_register(void)
 395{
 396        return spi_register_driver(&rx6110_spi_driver);
 397}
 398
 399static void rx6110_spi_unregister(void)
 400{
 401        spi_unregister_driver(&rx6110_spi_driver);
 402}
 403#else
 404static int rx6110_spi_register(void)
 405{
 406        return 0;
 407}
 408
 409static void rx6110_spi_unregister(void)
 410{
 411}
 412#endif /* CONFIG_SPI_MASTER */
 413
 414#if IS_ENABLED(CONFIG_I2C)
 415static 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
 422static 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
 450static const struct acpi_device_id rx6110_i2c_acpi_match[] = {
 451        { "SECC6110" },
 452        { }
 453};
 454MODULE_DEVICE_TABLE(acpi, rx6110_i2c_acpi_match);
 455
 456static const struct i2c_device_id rx6110_i2c_id[] = {
 457        { "rx6110", 0 },
 458        { }
 459};
 460MODULE_DEVICE_TABLE(i2c, rx6110_i2c_id);
 461
 462static struct i2c_driver rx6110_i2c_driver = {
 463        .driver = {
 464                .name = RX6110_DRIVER_NAME,
 465                .acpi_match_table = rx6110_i2c_acpi_match,
 466        },
 467        .probe          = rx6110_i2c_probe,
 468        .id_table       = rx6110_i2c_id,
 469};
 470
 471static int rx6110_i2c_register(void)
 472{
 473        return i2c_add_driver(&rx6110_i2c_driver);
 474}
 475
 476static void rx6110_i2c_unregister(void)
 477{
 478        i2c_del_driver(&rx6110_i2c_driver);
 479}
 480#else
 481static int rx6110_i2c_register(void)
 482{
 483        return 0;
 484}
 485
 486static void rx6110_i2c_unregister(void)
 487{
 488}
 489#endif /* CONFIG_I2C */
 490
 491static int __init rx6110_module_init(void)
 492{
 493        int ret;
 494
 495        ret = rx6110_spi_register();
 496        if (ret)
 497                return ret;
 498
 499        ret = rx6110_i2c_register();
 500        if (ret)
 501                rx6110_spi_unregister();
 502
 503        return ret;
 504}
 505module_init(rx6110_module_init);
 506
 507static void __exit rx6110_module_exit(void)
 508{
 509        rx6110_spi_unregister();
 510        rx6110_i2c_unregister();
 511}
 512module_exit(rx6110_module_exit);
 513
 514MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
 515MODULE_DESCRIPTION("RX-6110 SA RTC driver");
 516MODULE_LICENSE("GPL");
 517