drivers/rtc/rtc-rx8581.c

   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
  56 struct rx8581 {
  57         struct regmap           *regmap;
  58         struct rtc_device       *rtc;
  59 };
  60
  61 struct 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  */
  70 static 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
 136 static 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
 186 static const struct rtc_class_ops rx8581_rtc_ops = {
 187         .read_time      = rx8581_rtc_read_time,
 188         .set_time       = rx8581_rtc_set_time,
 189 };
 190
 191 static 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
 200 static 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
 209 static 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
 222 static 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
 233 static 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
 242 static 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
 251 static 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 = rtc_register_device(rx8581->rtc);
 302
 303         for (i = 0; i < config->num_nvram; i++) {
 304                 nvmem_cfg[i].priv = rx8581;
 305                 rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]);
 306         }
 307
 308         return ret;
 309 }
 310
 311 static const struct i2c_device_id rx8581_id[] = {
 312         { "rx8581", 0 },
 313         { }
 314 };
 315 MODULE_DEVICE_TABLE(i2c, rx8581_id);
 316
 317 static const struct of_device_id rx8581_of_match[] = {
 318         { .compatible = "epson,rx8571", .data = &rx8571_config },
 319         { .compatible = "epson,rx8581", .data = &rx8581_config },
 320         { /* sentinel */ }
 321 };
 322 MODULE_DEVICE_TABLE(of, rx8581_of_match);
 323
 324 static 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
 333 module_i2c_driver(rx8581_driver);
 334
 335 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
 336 MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver");
 337 MODULE_LICENSE("GPL");