drivers/rtc/rtc-rx8581.c

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