linux/drivers/rtc/rtc-rx8581.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * An I2C driver for the Epson RX8581 RTC
   4 *
   5 * Author: Martyn Welch <martyn.welch@ge.com>
   6 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
   7 *
   8 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
   9 * Copyright 2005-06 Tower Technologies
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/i2c.h>
  14#include <linux/bcd.h>
  15#include <linux/of.h>
  16#include <linux/of_device.h>
  17#include <linux/regmap.h>
  18#include <linux/rtc.h>
  19#include <linux/log2.h>
  20
  21#define RX8581_REG_SC           0x00 /* Second in BCD */
  22#define RX8581_REG_MN           0x01 /* Minute in BCD */
  23#define RX8581_REG_HR           0x02 /* Hour in BCD */
  24#define RX8581_REG_DW           0x03 /* Day of Week */
  25#define RX8581_REG_DM           0x04 /* Day of Month in BCD */
  26#define RX8581_REG_MO           0x05 /* Month in BCD */
  27#define RX8581_REG_YR           0x06 /* Year in BCD */
  28#define RX8581_REG_RAM          0x07 /* RAM */
  29#define RX8581_REG_AMN          0x08 /* Alarm Min in BCD*/
  30#define RX8581_REG_AHR          0x09 /* Alarm Hour in BCD */
  31#define RX8581_REG_ADM          0x0A
  32#define RX8581_REG_ADW          0x0A
  33#define RX8581_REG_TMR0         0x0B
  34#define RX8581_REG_TMR1         0x0C
  35#define RX8581_REG_EXT          0x0D /* Extension Register */
  36#define RX8581_REG_FLAG         0x0E /* Flag Register */
  37#define RX8581_REG_CTRL         0x0F /* Control Register */
  38
  39
  40/* Flag Register bit definitions */
  41#define RX8581_FLAG_UF          0x20 /* Update */
  42#define RX8581_FLAG_TF          0x10 /* Timer */
  43#define RX8581_FLAG_AF          0x08 /* Alarm */
  44#define RX8581_FLAG_VLF         0x02 /* Voltage Low */
  45
  46/* Control Register bit definitions */
  47#define RX8581_CTRL_UIE         0x20 /* Update Interrupt Enable */
  48#define RX8581_CTRL_TIE         0x10 /* Timer Interrupt Enable */
  49#define RX8581_CTRL_AIE         0x08 /* Alarm Interrupt Enable */
  50#define RX8581_CTRL_STOP        0x02 /* STOP bit */
  51#define RX8581_CTRL_RESET       0x01 /* RESET bit */
  52
  53#define RX8571_USER_RAM         0x10
  54#define RX8571_NVRAM_SIZE       0x10
  55
  56struct rx8581 {
  57        struct regmap           *regmap;
  58        struct rtc_device       *rtc;
  59};
  60
  61struct rx85x1_config {
  62        struct regmap_config regmap;
  63        unsigned int num_nvram;
  64};
  65
  66/*
  67 * In the routines that deal directly with the rx8581 hardware, we use
  68 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  69 */
  70static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
  71{
  72        struct i2c_client *client = to_i2c_client(dev);
  73        unsigned char date[7];
  74        unsigned int data;
  75        int err;
  76        struct rx8581 *rx8581 = i2c_get_clientdata(client);
  77
  78        /* First we ensure that the "update flag" is not set, we read the
  79         * time and date then re-read the "update flag". If the update flag
  80         * has been set, we know that the time has changed during the read so
  81         * we repeat the whole process again.
  82         */
  83        err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
  84        if (err < 0)
  85                return err;
  86
  87        if (data & RX8581_FLAG_VLF) {
  88                dev_warn(dev,
  89                         "low voltage detected, date/time is not reliable.\n");
  90                return -EINVAL;
  91        }
  92
  93        do {
  94                /* If update flag set, clear it */
  95                if (data & RX8581_FLAG_UF) {
  96                        err = regmap_write(rx8581->regmap, RX8581_REG_FLAG,
  97                                          data & ~RX8581_FLAG_UF);
  98                        if (err < 0)
  99                                return err;
 100                }
 101
 102                /* Now read time and date */
 103                err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date,
 104                                       sizeof(date));
 105                if (err < 0)
 106                        return err;
 107
 108                /* Check flag register */
 109                err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
 110                if (err < 0)
 111                        return err;
 112        } while (data & RX8581_FLAG_UF);
 113
 114        dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
 115                "wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
 116                __func__,
 117                date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
 118
 119        tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
 120        tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
 121        tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
 122        tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
 123        tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
 124        tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 125        tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100;
 126
 127        dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 128                "mday=%d, mon=%d, year=%d, wday=%d\n",
 129                __func__,
 130                tm->tm_sec, tm->tm_min, tm->tm_hour,
 131                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 132
 133        return 0;
 134}
 135
 136static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
 137{
 138        struct i2c_client *client = to_i2c_client(dev);
 139        int err;
 140        unsigned char buf[7];
 141        struct rx8581 *rx8581 = i2c_get_clientdata(client);
 142
 143        dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
 144                "mday=%d, mon=%d, year=%d, wday=%d\n",
 145                __func__,
 146                tm->tm_sec, tm->tm_min, tm->tm_hour,
 147                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 148
 149        /* hours, minutes and seconds */
 150        buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
 151        buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
 152        buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
 153
 154        buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
 155
 156        /* month, 1 - 12 */
 157        buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
 158
 159        /* year and century */
 160        buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100);
 161        buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
 162
 163        /* Stop the clock */
 164        err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
 165                                 RX8581_CTRL_STOP, RX8581_CTRL_STOP);
 166        if (err < 0)
 167                return err;
 168
 169        /* write register's data */
 170        err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC,
 171                                buf, sizeof(buf));
 172        if (err < 0)
 173                return err;
 174
 175        /* get VLF and clear it */
 176        err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG,
 177                                 RX8581_FLAG_VLF, 0);
 178        if (err < 0)
 179                return err;
 180
 181        /* Restart the clock */
 182        return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
 183                                 RX8581_CTRL_STOP, 0);
 184}
 185
 186static const struct rtc_class_ops rx8581_rtc_ops = {
 187        .read_time      = rx8581_rtc_read_time,
 188        .set_time       = rx8581_rtc_set_time,
 189};
 190
 191static int rx8571_nvram_read(void *priv, unsigned int offset, void *val,
 192                             size_t bytes)
 193{
 194        struct rx8581 *rx8581 = priv;
 195
 196        return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset,
 197                                val, bytes);
 198}
 199
 200static int rx8571_nvram_write(void *priv, unsigned int offset, void *val,
 201                              size_t bytes)
 202{
 203        struct rx8581 *rx8581 = priv;
 204
 205        return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset,
 206                                 val, bytes);
 207}
 208
 209static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val,
 210                             size_t bytes)
 211{
 212        struct rx8581 *rx8581 = priv;
 213        unsigned int tmp_val;
 214        int ret;
 215
 216        ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val);
 217        (*(unsigned char *)val) = (unsigned char) tmp_val;
 218
 219        return ret;
 220}
 221
 222static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val,
 223                              size_t bytes)
 224{
 225        struct rx8581 *rx8581 = priv;
 226        unsigned char tmp_val;
 227
 228        tmp_val = *((unsigned char *)val);
 229        return regmap_write(rx8581->regmap, RX8581_REG_RAM,
 230                                (unsigned int)tmp_val);
 231}
 232
 233static const struct rx85x1_config rx8581_config = {
 234        .regmap = {
 235                .reg_bits = 8,
 236                .val_bits = 8,
 237                .max_register = 0xf,
 238        },
 239        .num_nvram = 1
 240};
 241
 242static const struct rx85x1_config rx8571_config = {
 243        .regmap = {
 244                .reg_bits = 8,
 245                .val_bits = 8,
 246                .max_register = 0x1f,
 247        },
 248        .num_nvram = 2
 249};
 250
 251static int rx8581_probe(struct i2c_client *client,
 252                        const struct i2c_device_id *id)
 253{
 254        struct rx8581 *rx8581;
 255        const struct rx85x1_config *config = &rx8581_config;
 256        const void *data = of_device_get_match_data(&client->dev);
 257        static struct nvmem_config nvmem_cfg[] = {
 258                {
 259                        .name = "rx85x1-",
 260                        .word_size = 1,
 261                        .stride = 1,
 262                        .size = 1,
 263                        .reg_read = rx85x1_nvram_read,
 264                        .reg_write = rx85x1_nvram_write,
 265                }, {
 266                        .name = "rx8571-",
 267                        .word_size = 1,
 268                        .stride = 1,
 269                        .size = RX8571_NVRAM_SIZE,
 270                        .reg_read = rx8571_nvram_read,
 271                        .reg_write = rx8571_nvram_write,
 272                },
 273        };
 274        int ret, i;
 275
 276        dev_dbg(&client->dev, "%s\n", __func__);
 277
 278        if (data)
 279                config = data;
 280
 281        rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
 282        if (!rx8581)
 283                return -ENOMEM;
 284
 285        i2c_set_clientdata(client, rx8581);
 286
 287        rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap);
 288        if (IS_ERR(rx8581->regmap))
 289                return PTR_ERR(rx8581->regmap);
 290
 291        rx8581->rtc = devm_rtc_allocate_device(&client->dev);
 292        if (IS_ERR(rx8581->rtc))
 293                return PTR_ERR(rx8581->rtc);
 294
 295        rx8581->rtc->ops = &rx8581_rtc_ops;
 296        rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 297        rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099;
 298        rx8581->rtc->start_secs = 0;
 299        rx8581->rtc->set_start_time = true;
 300
 301        ret = devm_rtc_register_device(rx8581->rtc);
 302
 303        for (i = 0; i < config->num_nvram; i++) {
 304                nvmem_cfg[i].priv = rx8581;
 305                devm_rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]);
 306        }
 307
 308        return ret;
 309}
 310
 311static const struct i2c_device_id rx8581_id[] = {
 312        { "rx8581", 0 },
 313        { }
 314};
 315MODULE_DEVICE_TABLE(i2c, rx8581_id);
 316
 317static const __maybe_unused struct of_device_id rx8581_of_match[] = {
 318        { .compatible = "epson,rx8571", .data = &rx8571_config },
 319        { .compatible = "epson,rx8581", .data = &rx8581_config },
 320        { /* sentinel */ }
 321};
 322MODULE_DEVICE_TABLE(of, rx8581_of_match);
 323
 324static struct i2c_driver rx8581_driver = {
 325        .driver         = {
 326                .name   = "rtc-rx8581",
 327                .of_match_table = of_match_ptr(rx8581_of_match),
 328        },
 329        .probe          = rx8581_probe,
 330        .id_table       = rx8581_id,
 331};
 332
 333module_i2c_driver(rx8581_driver);
 334
 335MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
 336MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver");
 337MODULE_LICENSE("GPL");
 338