drivers/rtc/rtc-rv3029c2.c

   1 /*
   2  * Micro Crystal RV-3029C2 rtc class driver
   3  *
   4  * Author: Gregory Hermant <gregory.hermant@calao-systems.com>
   5  *
   6  * based on previously existing rtc class drivers
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * NOTE: Currently this driver only supports the bare minimum for read
  13  * and write the RTC and alarms. The extra features provided by this chip
  14  * (trickle charger, eeprom, T° compensation) are unavailable.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/i2c.h>
  19 #include <linux/bcd.h>
  20 #include <linux/rtc.h>
  21
  22 /* Register map */
  23 /* control section */
  24 #define RV3029C2_ONOFF_CTRL             0x00
  25 #define RV3029C2_IRQ_CTRL               0x01
  26 #define RV3029C2_IRQ_CTRL_AIE           (1 << 0)
  27 #define RV3029C2_IRQ_FLAGS              0x02
  28 #define RV3029C2_IRQ_FLAGS_AF           (1 << 0)
  29 #define RV3029C2_STATUS                 0x03
  30 #define RV3029C2_STATUS_VLOW1           (1 << 2)
  31 #define RV3029C2_STATUS_VLOW2           (1 << 3)
  32 #define RV3029C2_STATUS_SR              (1 << 4)
  33 #define RV3029C2_STATUS_PON             (1 << 5)
  34 #define RV3029C2_STATUS_EEBUSY          (1 << 7)
  35 #define RV3029C2_RST_CTRL               0x04
  36 #define RV3029C2_CONTROL_SECTION_LEN    0x05
  37
  38 /* watch section */
  39 #define RV3029C2_W_SEC                  0x08
  40 #define RV3029C2_W_MINUTES              0x09
  41 #define RV3029C2_W_HOURS                0x0A
  42 #define RV3029C2_REG_HR_12_24           (1<<6)  /* 24h/12h mode */
  43 #define RV3029C2_REG_HR_PM              (1<<5)  /* PM/AM bit in 12h mode */
  44 #define RV3029C2_W_DATE                 0x0B
  45 #define RV3029C2_W_DAYS                 0x0C
  46 #define RV3029C2_W_MONTHS               0x0D
  47 #define RV3029C2_W_YEARS                0x0E
  48 #define RV3029C2_WATCH_SECTION_LEN      0x07
  49
  50 /* alarm section */
  51 #define RV3029C2_A_SC                   0x10
  52 #define RV3029C2_A_MN                   0x11
  53 #define RV3029C2_A_HR                   0x12
  54 #define RV3029C2_A_DT                   0x13
  55 #define RV3029C2_A_DW                   0x14
  56 #define RV3029C2_A_MO                   0x15
  57 #define RV3029C2_A_YR                   0x16
  58 #define RV3029C2_ALARM_SECTION_LEN      0x07
  59
  60 /* timer section */
  61 #define RV3029C2_TIMER_LOW              0x18
  62 #define RV3029C2_TIMER_HIGH             0x19
  63
  64 /* temperature section */
  65 #define RV3029C2_TEMP_PAGE              0x20
  66
  67 /* eeprom data section */
  68 #define RV3029C2_E2P_EEDATA1            0x28
  69 #define RV3029C2_E2P_EEDATA2            0x29
  70
  71 /* eeprom control section */
  72 #define RV3029C2_CONTROL_E2P_EECTRL     0x30
  73 #define RV3029C2_TRICKLE_1K             (1<<0)  /*  1K resistance */
  74 #define RV3029C2_TRICKLE_5K             (1<<1)  /*  5K resistance */
  75 #define RV3029C2_TRICKLE_20K            (1<<2)  /* 20K resistance */
  76 #define RV3029C2_TRICKLE_80K            (1<<3)  /* 80K resistance */
  77 #define RV3029C2_CONTROL_E2P_XTALOFFSET 0x31
  78 #define RV3029C2_CONTROL_E2P_QCOEF      0x32
  79 #define RV3029C2_CONTROL_E2P_TURNOVER   0x33
  80
  81 /* user ram section */
  82 #define RV3029C2_USR1_RAM_PAGE          0x38
  83 #define RV3029C2_USR1_SECTION_LEN       0x04
  84 #define RV3029C2_USR2_RAM_PAGE          0x3C
  85 #define RV3029C2_USR2_SECTION_LEN       0x04
  86
  87 static int
  88 rv3029c2_i2c_read_regs(struct i2c_client *client, u8 reg, u8 *buf,
  89         unsigned len)
  90 {
  91         int ret;
  92
  93         if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
  94                 (reg + len > RV3029C2_USR1_RAM_PAGE + 8))
  95                 return -EINVAL;
  96
  97         ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
  98         if (ret < 0)
  99                 return ret;
 100         if (ret < len)
 101                 return -EIO;
 102         return 0;
 103 }
 104
 105 static int
 106 rv3029c2_i2c_write_regs(struct i2c_client *client, u8 reg, u8 const buf[],
 107                         unsigned len)
 108 {
 109         if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
 110                 (reg + len > RV3029C2_USR1_RAM_PAGE + 8))
 111                 return -EINVAL;
 112
 113         return i2c_smbus_write_i2c_block_data(client, reg, len, buf);
 114 }
 115
 116 static int
 117 rv3029c2_i2c_get_sr(struct i2c_client *client, u8 *buf)
 118 {
 119         int ret = rv3029c2_i2c_read_regs(client, RV3029C2_STATUS, buf, 1);
 120
 121         if (ret < 0)
 122                 return -EIO;
 123         dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
 124         return 0;
 125 }
 126
 127 static int
 128 rv3029c2_i2c_set_sr(struct i2c_client *client, u8 val)
 129 {
 130         u8 buf[1];
 131         int sr;
 132
 133         buf[0] = val;
 134         sr = rv3029c2_i2c_write_regs(client, RV3029C2_STATUS, buf, 1);
 135         dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
 136         if (sr < 0)
 137                 return -EIO;
 138         return 0;
 139 }
 140
 141 static int
 142 rv3029c2_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
 143 {
 144         u8 buf[1];
 145         int ret;
 146         u8 regs[RV3029C2_WATCH_SECTION_LEN] = { 0, };
 147
 148         ret = rv3029c2_i2c_get_sr(client, buf);
 149         if (ret < 0) {
 150                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 151                 return -EIO;
 152         }
 153
 154         ret = rv3029c2_i2c_read_regs(client, RV3029C2_W_SEC , regs,
 155                                         RV3029C2_WATCH_SECTION_LEN);
 156         if (ret < 0) {
 157                 dev_err(&client->dev, "%s: reading RTC section failed\n",
 158                         __func__);
 159                 return ret;
 160         }
 161
 162         tm->tm_sec = bcd2bin(regs[RV3029C2_W_SEC-RV3029C2_W_SEC]);
 163         tm->tm_min = bcd2bin(regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC]);
 164
 165         /* HR field has a more complex interpretation */
 166         {
 167                 const u8 _hr = regs[RV3029C2_W_HOURS-RV3029C2_W_SEC];
 168                 if (_hr & RV3029C2_REG_HR_12_24) {
 169                         /* 12h format */
 170                         tm->tm_hour = bcd2bin(_hr & 0x1f);
 171                         if (_hr & RV3029C2_REG_HR_PM)   /* PM flag set */
 172                                 tm->tm_hour += 12;
 173                 } else /* 24h format */
 174                         tm->tm_hour = bcd2bin(_hr & 0x3f);
 175         }
 176
 177         tm->tm_mday = bcd2bin(regs[RV3029C2_W_DATE-RV3029C2_W_SEC]);
 178         tm->tm_mon = bcd2bin(regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC]) - 1;
 179         tm->tm_year = bcd2bin(regs[RV3029C2_W_YEARS-RV3029C2_W_SEC]) + 100;
 180         tm->tm_wday = bcd2bin(regs[RV3029C2_W_DAYS-RV3029C2_W_SEC]) - 1;
 181
 182         return 0;
 183 }
 184
 185 static int rv3029c2_rtc_read_time(struct device *dev, struct rtc_time *tm)
 186 {
 187         return rv3029c2_i2c_read_time(to_i2c_client(dev), tm);
 188 }
 189
 190 static int
 191 rv3029c2_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
 192 {
 193         struct rtc_time *const tm = &alarm->time;
 194         int ret;
 195         u8 regs[8];
 196
 197         ret = rv3029c2_i2c_get_sr(client, regs);
 198         if (ret < 0) {
 199                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 200                 return -EIO;
 201         }
 202
 203         ret = rv3029c2_i2c_read_regs(client, RV3029C2_A_SC, regs,
 204                                         RV3029C2_ALARM_SECTION_LEN);
 205
 206         if (ret < 0) {
 207                 dev_err(&client->dev, "%s: reading alarm section failed\n",
 208                         __func__);
 209                 return ret;
 210         }
 211
 212         tm->tm_sec = bcd2bin(regs[RV3029C2_A_SC-RV3029C2_A_SC] & 0x7f);
 213         tm->tm_min = bcd2bin(regs[RV3029C2_A_MN-RV3029C2_A_SC] & 0x7f);
 214         tm->tm_hour = bcd2bin(regs[RV3029C2_A_HR-RV3029C2_A_SC] & 0x3f);
 215         tm->tm_mday = bcd2bin(regs[RV3029C2_A_DT-RV3029C2_A_SC] & 0x3f);
 216         tm->tm_mon = bcd2bin(regs[RV3029C2_A_MO-RV3029C2_A_SC] & 0x1f) - 1;
 217         tm->tm_year = bcd2bin(regs[RV3029C2_A_YR-RV3029C2_A_SC] & 0x7f) + 100;
 218         tm->tm_wday = bcd2bin(regs[RV3029C2_A_DW-RV3029C2_A_SC] & 0x07) - 1;
 219
 220         return 0;
 221 }
 222
 223 static int
 224 rv3029c2_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 225 {
 226         return rv3029c2_i2c_read_alarm(to_i2c_client(dev), alarm);
 227 }
 228
 229 static int rv3029c2_rtc_i2c_alarm_set_irq(struct i2c_client *client,
 230                                         int enable)
 231 {
 232         int ret;
 233         u8 buf[1];
 234
 235         /* enable AIE irq */
 236         ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
 237         if (ret < 0) {
 238                 dev_err(&client->dev, "can't read INT reg\n");
 239                 return ret;
 240         }
 241         if (enable)
 242                 buf[0] |= RV3029C2_IRQ_CTRL_AIE;
 243         else
 244                 buf[0] &= ~RV3029C2_IRQ_CTRL_AIE;
 245
 246         ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
 247         if (ret < 0) {
 248                 dev_err(&client->dev, "can't set INT reg\n");
 249                 return ret;
 250         }
 251
 252         return 0;
 253 }
 254
 255 static int rv3029c2_rtc_i2c_set_alarm(struct i2c_client *client,
 256                                         struct rtc_wkalrm *alarm)
 257 {
 258         struct rtc_time *const tm = &alarm->time;
 259         int ret;
 260         u8 regs[8];
 261
 262         /*
 263          * The clock has an 8 bit wide bcd-coded register (they never learn)
 264          * for the year. tm_year is an offset from 1900 and we are interested
 265          * in the 2000-2099 range, so any value less than 100 is invalid.
 266         */
 267         if (tm->tm_year < 100)
 268                 return -EINVAL;
 269
 270         ret = rv3029c2_i2c_get_sr(client, regs);
 271         if (ret < 0) {
 272                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 273                 return -EIO;
 274         }
 275         regs[RV3029C2_A_SC-RV3029C2_A_SC] = bin2bcd(tm->tm_sec & 0x7f);
 276         regs[RV3029C2_A_MN-RV3029C2_A_SC] = bin2bcd(tm->tm_min & 0x7f);
 277         regs[RV3029C2_A_HR-RV3029C2_A_SC] = bin2bcd(tm->tm_hour & 0x3f);
 278         regs[RV3029C2_A_DT-RV3029C2_A_SC] = bin2bcd(tm->tm_mday & 0x3f);
 279         regs[RV3029C2_A_MO-RV3029C2_A_SC] = bin2bcd((tm->tm_mon & 0x1f) - 1);
 280         regs[RV3029C2_A_DW-RV3029C2_A_SC] = bin2bcd((tm->tm_wday & 7) - 1);
 281         regs[RV3029C2_A_YR-RV3029C2_A_SC] = bin2bcd((tm->tm_year & 0x7f) - 100);
 282
 283         ret = rv3029c2_i2c_write_regs(client, RV3029C2_A_SC, regs,
 284                                         RV3029C2_ALARM_SECTION_LEN);
 285         if (ret < 0)
 286                 return ret;
 287
 288         if (alarm->enabled) {
 289                 u8 buf[1];
 290
 291                 /* clear AF flag */
 292                 ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_FLAGS,
 293                                                 buf, 1);
 294                 if (ret < 0) {
 295                         dev_err(&client->dev, "can't read alarm flag\n");
 296                         return ret;
 297                 }
 298                 buf[0] &= ~RV3029C2_IRQ_FLAGS_AF;
 299                 ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_FLAGS,
 300                                                 buf, 1);
 301                 if (ret < 0) {
 302                         dev_err(&client->dev, "can't set alarm flag\n");
 303                         return ret;
 304                 }
 305                 /* enable AIE irq */
 306                 ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
 307                 if (ret)
 308                         return ret;
 309
 310                 dev_dbg(&client->dev, "alarm IRQ armed\n");
 311         } else {
 312                 /* disable AIE irq */
 313                 ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 0);
 314                 if (ret)
 315                         return ret;
 316
 317                 dev_dbg(&client->dev, "alarm IRQ disabled\n");
 318         }
 319
 320         return 0;
 321 }
 322
 323 static int rv3029c2_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 324 {
 325         return rv3029c2_rtc_i2c_set_alarm(to_i2c_client(dev), alarm);
 326 }
 327
 328 static int
 329 rv3029c2_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
 330 {
 331         u8 regs[8];
 332         int ret;
 333
 334         /*
 335          * The clock has an 8 bit wide bcd-coded register (they never learn)
 336          * for the year. tm_year is an offset from 1900 and we are interested
 337          * in the 2000-2099 range, so any value less than 100 is invalid.
 338         */
 339         if (tm->tm_year < 100)
 340                 return -EINVAL;
 341
 342         regs[RV3029C2_W_SEC-RV3029C2_W_SEC] = bin2bcd(tm->tm_sec);
 343         regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC] = bin2bcd(tm->tm_min);
 344         regs[RV3029C2_W_HOURS-RV3029C2_W_SEC] = bin2bcd(tm->tm_hour);
 345         regs[RV3029C2_W_DATE-RV3029C2_W_SEC] = bin2bcd(tm->tm_mday);
 346         regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC] = bin2bcd(tm->tm_mon+1);
 347         regs[RV3029C2_W_DAYS-RV3029C2_W_SEC] = bin2bcd((tm->tm_wday & 7)+1);
 348         regs[RV3029C2_W_YEARS-RV3029C2_W_SEC] = bin2bcd(tm->tm_year - 100);
 349
 350         ret = rv3029c2_i2c_write_regs(client, RV3029C2_W_SEC, regs,
 351                                         RV3029C2_WATCH_SECTION_LEN);
 352         if (ret < 0)
 353                 return ret;
 354
 355         ret = rv3029c2_i2c_get_sr(client, regs);
 356         if (ret < 0) {
 357                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 358                 return ret;
 359         }
 360         /* clear PON bit */
 361         ret = rv3029c2_i2c_set_sr(client, (regs[0] & ~RV3029C2_STATUS_PON));
 362         if (ret < 0) {
 363                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 364                 return ret;
 365         }
 366
 367         return 0;
 368 }
 369
 370 static int rv3029c2_rtc_set_time(struct device *dev, struct rtc_time *tm)
 371 {
 372         return rv3029c2_i2c_set_time(to_i2c_client(dev), tm);
 373 }
 374
 375 static const struct rtc_class_ops rv3029c2_rtc_ops = {
 376         .read_time      = rv3029c2_rtc_read_time,
 377         .set_time       = rv3029c2_rtc_set_time,
 378         .read_alarm     = rv3029c2_rtc_read_alarm,
 379         .set_alarm      = rv3029c2_rtc_set_alarm,
 380 };
 381
 382 static struct i2c_device_id rv3029c2_id[] = {
 383         { "rv3029c2", 0 },
 384         { }
 385 };
 386 MODULE_DEVICE_TABLE(i2c, rv3029c2_id);
 387
 388 static int rv3029c2_probe(struct i2c_client *client,
 389                           const struct i2c_device_id *id)
 390 {
 391         struct rtc_device *rtc;
 392         int rc = 0;
 393         u8 buf[1];
 394
 395         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_EMUL))
 396                 return -ENODEV;
 397
 398         rc = rv3029c2_i2c_get_sr(client, buf);
 399         if (rc < 0) {
 400                 dev_err(&client->dev, "reading status failed\n");
 401                 return rc;
 402         }
 403
 404         rtc = devm_rtc_device_register(&client->dev, client->name,
 405                                         &rv3029c2_rtc_ops, THIS_MODULE);
 406
 407         if (IS_ERR(rtc))
 408                 return PTR_ERR(rtc);
 409
 410         i2c_set_clientdata(client, rtc);
 411
 412         return 0;
 413 }
 414
 415 static struct i2c_driver rv3029c2_driver = {
 416         .driver = {
 417                 .name = "rtc-rv3029c2",
 418         },
 419         .probe = rv3029c2_probe,
 420         .id_table = rv3029c2_id,
 421 };
 422
 423 module_i2c_driver(rv3029c2_driver);
 424
 425 MODULE_AUTHOR("Gregory Hermant <gregory.hermant@calao-systems.com>");
 426 MODULE_DESCRIPTION("Micro Crystal RV3029C2 RTC driver");
 427 MODULE_LICENSE("GPL");