kernel/drivers/rtc/rtc-pcf8563.c

   1 /*
   2  * An I2C driver for the Philips PCF8563 RTC
   3  * Copyright 2005-06 Tower Technologies
   4  *
   5  * Author: Alessandro Zummo <a.zummo@towertech.it>
   6  * Maintainers: http://www.nslu2-linux.org/
   7  *
   8  * based on the other drivers in this same directory.
   9  *
  10  * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  */
  16
  17 #include <linux/i2c.h>
  18 #include <linux/bcd.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21 #include <linux/module.h>
  22 #include <linux/of.h>
  23 #include <linux/err.h>
  24
  25 #define DRV_VERSION "0.4.3"
  26
  27 #define PCF8563_REG_ST1         0x00 /* status */
  28 #define PCF8563_REG_ST2         0x01
  29 #define PCF8563_BIT_AIE         (1 << 1)
  30 #define PCF8563_BIT_AF          (1 << 3)
  31 #define PCF8563_BITS_ST2_N      (7 << 5)
  32
  33 #define PCF8563_REG_SC          0x02 /* datetime */
  34 #define PCF8563_REG_MN          0x03
  35 #define PCF8563_REG_HR          0x04
  36 #define PCF8563_REG_DM          0x05
  37 #define PCF8563_REG_DW          0x06
  38 #define PCF8563_REG_MO          0x07
  39 #define PCF8563_REG_YR          0x08
  40
  41 #define PCF8563_REG_AMN         0x09 /* alarm */
  42
  43 #define PCF8563_REG_CLKO        0x0D /* clock out */
  44 #define PCF8563_REG_TMRC        0x0E /* timer control */
  45 #define PCF8563_TMRC_ENABLE     BIT(7)
  46 #define PCF8563_TMRC_4096       0
  47 #define PCF8563_TMRC_64         1
  48 #define PCF8563_TMRC_1          2
  49 #define PCF8563_TMRC_1_60       3
  50 #define PCF8563_TMRC_MASK       3
  51
  52 #define PCF8563_REG_TMR         0x0F /* timer */
  53
  54 #define PCF8563_SC_LV           0x80 /* low voltage */
  55 #define PCF8563_MO_C            0x80 /* century */
  56
  57 static struct i2c_driver pcf8563_driver;
  58
  59 struct pcf8563 {
  60         struct rtc_device *rtc;
  61         /*
  62          * The meaning of MO_C bit varies by the chip type.
  63          * From PCF8563 datasheet: this bit is toggled when the years
  64          * register overflows from 99 to 00
  65          *   0 indicates the century is 20xx
  66          *   1 indicates the century is 19xx
  67          * From RTC8564 datasheet: this bit indicates change of
  68          * century. When the year digit data overflows from 99 to 00,
  69          * this bit is set. By presetting it to 0 while still in the
  70          * 20th century, it will be set in year 2000, ...
  71          * There seems no reliable way to know how the system use this
  72          * bit.  So let's do it heuristically, assuming we are live in
  73          * 1970...2069.
  74          */
  75         int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
  76         int voltage_low; /* incicates if a low_voltage was detected */
  77
  78         struct i2c_client *client;
  79 };
  80
  81 static int pcf8563_read_block_data(struct i2c_client *client, unsigned char reg,
  82                                    unsigned char length, unsigned char *buf)
  83 {
  84         struct i2c_msg msgs[] = {
  85                 {/* setup read ptr */
  86                         .addr = client->addr,
  87                         .len = 1,
  88                         .buf = &reg,
  89                 },
  90                 {
  91                         .addr = client->addr,
  92                         .flags = I2C_M_RD,
  93                         .len = length,
  94                         .buf = buf
  95                 },
  96         };
  97
  98         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  99                 dev_err(&client->dev, "%s: read error\n", __func__);
 100                 return -EIO;
 101         }
 102
 103         return 0;
 104 }
 105
 106 static int pcf8563_write_block_data(struct i2c_client *client,
 107                                    unsigned char reg, unsigned char length,
 108                                    unsigned char *buf)
 109 {
 110         int i, err;
 111
 112         for (i = 0; i < length; i++) {
 113                 unsigned char data[2] = { reg + i, buf[i] };
 114
 115                 err = i2c_master_send(client, data, sizeof(data));
 116                 if (err != sizeof(data)) {
 117                         dev_err(&client->dev,
 118                                 "%s: err=%d addr=%02x, data=%02x\n",
 119                                 __func__, err, data[0], data[1]);
 120                         return -EIO;
 121                 }
 122         }
 123
 124         return 0;
 125 }
 126
 127 static int pcf8563_set_alarm_mode(struct i2c_client *client, bool on)
 128 {
 129         unsigned char buf;
 130         int err;
 131
 132         err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
 133         if (err < 0)
 134                 return err;
 135
 136         if (on)
 137                 buf |= PCF8563_BIT_AIE;
 138         else
 139                 buf &= ~PCF8563_BIT_AIE;
 140
 141         buf &= ~(PCF8563_BIT_AF | PCF8563_BITS_ST2_N);
 142
 143         err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
 144         if (err < 0) {
 145                 dev_err(&client->dev, "%s: write error\n", __func__);
 146                 return -EIO;
 147         }
 148
 149         return 0;
 150 }
 151
 152 static int pcf8563_get_alarm_mode(struct i2c_client *client, unsigned char *en,
 153                                   unsigned char *pen)
 154 {
 155         unsigned char buf;
 156         int err;
 157
 158         err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
 159         if (err)
 160                 return err;
 161
 162         if (en)
 163                 *en = !!(buf & PCF8563_BIT_AIE);
 164         if (pen)
 165                 *pen = !!(buf & PCF8563_BIT_AF);
 166
 167         return 0;
 168 }
 169
 170 static irqreturn_t pcf8563_irq(int irq, void *dev_id)
 171 {
 172         struct pcf8563 *pcf8563 = i2c_get_clientdata(dev_id);
 173         int err;
 174         char pending;
 175
 176         err = pcf8563_get_alarm_mode(pcf8563->client, NULL, &pending);
 177         if (err)
 178                 return IRQ_NONE;
 179
 180         if (pending) {
 181                 rtc_update_irq(pcf8563->rtc, 1, RTC_IRQF | RTC_AF);
 182                 pcf8563_set_alarm_mode(pcf8563->client, 1);
 183                 return IRQ_HANDLED;
 184         }
 185
 186         return IRQ_NONE;
 187 }
 188
 189 /*
 190  * In the routines that deal directly with the pcf8563 hardware, we use
 191  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 192  */
 193 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 194 {
 195         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 196         unsigned char buf[9];
 197         int err;
 198
 199         err = pcf8563_read_block_data(client, PCF8563_REG_ST1, 9, buf);
 200         if (err)
 201                 return err;
 202
 203         if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
 204                 pcf8563->voltage_low = 1;
 205                 dev_info(&client->dev,
 206                         "low voltage detected, date/time is not reliable.\n");
 207         }
 208
 209         dev_dbg(&client->dev,
 210                 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
 211                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
 212                 __func__,
 213                 buf[0], buf[1], buf[2], buf[3],
 214                 buf[4], buf[5], buf[6], buf[7],
 215                 buf[8]);
 216
 217
 218         tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
 219         tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
 220         tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
 221         tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
 222         tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
 223         tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 224         tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
 225         if (tm->tm_year < 70)
 226                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
 227         /* detect the polarity heuristically. see note above. */
 228         pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
 229                 (tm->tm_year >= 100) : (tm->tm_year < 100);
 230
 231         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 232                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 233                 __func__,
 234                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 235                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 236
 237         /* the clock can give out invalid datetime, but we cannot return
 238          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
 239          */
 240         if (rtc_valid_tm(tm) < 0)
 241                 dev_err(&client->dev, "retrieved date/time is not valid.\n");
 242
 243         return 0;
 244 }
 245
 246 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 247 {
 248         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 249         unsigned char buf[9];
 250
 251         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 252                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 253                 __func__,
 254                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 255                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 256
 257         /* hours, minutes and seconds */
 258         buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
 259         buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
 260         buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
 261
 262         buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
 263
 264         /* month, 1 - 12 */
 265         buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
 266
 267         /* year and century */
 268         buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
 269         if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
 270                 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
 271
 272         buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 273
 274         return pcf8563_write_block_data(client, PCF8563_REG_SC,
 275                                 9 - PCF8563_REG_SC, buf + PCF8563_REG_SC);
 276 }
 277
 278 #ifdef CONFIG_RTC_INTF_DEV
 279 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 280 {
 281         struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
 282         struct rtc_time tm;
 283
 284         switch (cmd) {
 285         case RTC_VL_READ:
 286                 if (pcf8563->voltage_low)
 287                         dev_info(dev, "low voltage detected, date/time is not reliable.\n");
 288
 289                 if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
 290                                         sizeof(int)))
 291                         return -EFAULT;
 292                 return 0;
 293         case RTC_VL_CLR:
 294                 /*
 295                  * Clear the VL bit in the seconds register in case
 296                  * the time has not been set already (which would
 297                  * have cleared it). This does not really matter
 298                  * because of the cached voltage_low value but do it
 299                  * anyway for consistency.
 300                  */
 301                 if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
 302                         pcf8563_set_datetime(to_i2c_client(dev), &tm);
 303
 304                 /* Clear the cached value. */
 305                 pcf8563->voltage_low = 0;
 306
 307                 return 0;
 308         default:
 309                 return -ENOIOCTLCMD;
 310         }
 311 }
 312 #else
 313 #define pcf8563_rtc_ioctl NULL
 314 #endif
 315
 316 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 317 {
 318         return pcf8563_get_datetime(to_i2c_client(dev), tm);
 319 }
 320
 321 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 322 {
 323         return pcf8563_set_datetime(to_i2c_client(dev), tm);
 324 }
 325
 326 static int pcf8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
 327 {
 328         struct i2c_client *client = to_i2c_client(dev);
 329         unsigned char buf[4];
 330         int err;
 331
 332         err = pcf8563_read_block_data(client, PCF8563_REG_AMN, 4, buf);
 333         if (err)
 334                 return err;
 335
 336         dev_dbg(&client->dev,
 337                 "%s: raw data is min=%02x, hr=%02x, mday=%02x, wday=%02x\n",
 338                 __func__, buf[0], buf[1], buf[2], buf[3]);
 339
 340         tm->time.tm_min = bcd2bin(buf[0] & 0x7F);
 341         tm->time.tm_hour = bcd2bin(buf[1] & 0x3F);
 342         tm->time.tm_mday = bcd2bin(buf[2] & 0x3F);
 343         tm->time.tm_wday = bcd2bin(buf[3] & 0x7);
 344         tm->time.tm_mon = -1;
 345         tm->time.tm_year = -1;
 346         tm->time.tm_yday = -1;
 347         tm->time.tm_isdst = -1;
 348
 349         err = pcf8563_get_alarm_mode(client, &tm->enabled, &tm->pending);
 350         if (err < 0)
 351                 return err;
 352
 353         dev_dbg(&client->dev, "%s: tm is mins=%d, hours=%d, mday=%d, wday=%d,"
 354                 " enabled=%d, pending=%d\n", __func__, tm->time.tm_min,
 355                 tm->time.tm_hour, tm->time.tm_mday, tm->time.tm_wday,
 356                 tm->enabled, tm->pending);
 357
 358         return 0;
 359 }
 360
 361 static int pcf8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 362 {
 363         struct i2c_client *client = to_i2c_client(dev);
 364         unsigned char buf[4];
 365         int err;
 366         unsigned long alarm_time;
 367
 368         /* The alarm has no seconds, round up to nearest minute */
 369         if (tm->time.tm_sec) {
 370                 rtc_tm_to_time(&tm->time, &alarm_time);
 371                 alarm_time += 60-tm->time.tm_sec;
 372                 rtc_time_to_tm(alarm_time, &tm->time);
 373         }
 374
 375         dev_dbg(dev, "%s, min=%d hour=%d wday=%d mday=%d "
 376                 "enabled=%d pending=%d\n", __func__,
 377                 tm->time.tm_min, tm->time.tm_hour, tm->time.tm_wday,
 378                 tm->time.tm_mday, tm->enabled, tm->pending);
 379
 380         buf[0] = bin2bcd(tm->time.tm_min);
 381         buf[1] = bin2bcd(tm->time.tm_hour);
 382         buf[2] = bin2bcd(tm->time.tm_mday);
 383         buf[3] = tm->time.tm_wday & 0x07;
 384
 385         err = pcf8563_write_block_data(client, PCF8563_REG_AMN, 4, buf);
 386         if (err)
 387                 return err;
 388
 389         return pcf8563_set_alarm_mode(client, 1);
 390 }
 391
 392 static int pcf8563_irq_enable(struct device *dev, unsigned int enabled)
 393 {
 394         dev_dbg(dev, "%s: en=%d\n", __func__, enabled);
 395         return pcf8563_set_alarm_mode(to_i2c_client(dev), !!enabled);
 396 }
 397
 398 static const struct rtc_class_ops pcf8563_rtc_ops = {
 399         .ioctl          = pcf8563_rtc_ioctl,
 400         .read_time      = pcf8563_rtc_read_time,
 401         .set_time       = pcf8563_rtc_set_time,
 402         .read_alarm     = pcf8563_rtc_read_alarm,
 403         .set_alarm      = pcf8563_rtc_set_alarm,
 404         .alarm_irq_enable = pcf8563_irq_enable,
 405 };
 406
 407 static int pcf8563_probe(struct i2c_client *client,
 408                                 const struct i2c_device_id *id)
 409 {
 410         struct pcf8563 *pcf8563;
 411         int err;
 412         unsigned char buf;
 413         unsigned char alm_pending;
 414
 415         dev_dbg(&client->dev, "%s\n", __func__);
 416
 417         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 418                 return -ENODEV;
 419
 420         pcf8563 = devm_kzalloc(&client->dev, sizeof(struct pcf8563),
 421                                 GFP_KERNEL);
 422         if (!pcf8563)
 423                 return -ENOMEM;
 424
 425         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 426
 427         i2c_set_clientdata(client, pcf8563);
 428         pcf8563->client = client;
 429         device_set_wakeup_capable(&client->dev, 1);
 430
 431         /* Set timer to lowest frequency to save power (ref Haoyu datasheet) */
 432         buf = PCF8563_TMRC_1_60;
 433         err = pcf8563_write_block_data(client, PCF8563_REG_TMRC, 1, &buf);
 434         if (err < 0) {
 435                 dev_err(&client->dev, "%s: write error\n", __func__);
 436                 return err;
 437         }
 438
 439         err = pcf8563_get_alarm_mode(client, NULL, &alm_pending);
 440         if (err < 0) {
 441                 dev_err(&client->dev, "%s: read error\n", __func__);
 442                 return err;
 443         }
 444         if (alm_pending)
 445                 pcf8563_set_alarm_mode(client, 0);
 446
 447         pcf8563->rtc = devm_rtc_device_register(&client->dev,
 448                                 pcf8563_driver.driver.name,
 449                                 &pcf8563_rtc_ops, THIS_MODULE);
 450
 451         if (IS_ERR(pcf8563->rtc))
 452                 return PTR_ERR(pcf8563->rtc);
 453
 454         if (client->irq > 0) {
 455                 err = devm_request_threaded_irq(&client->dev, client->irq,
 456                                 NULL, pcf8563_irq,
 457                                 IRQF_SHARED|IRQF_ONESHOT|IRQF_TRIGGER_FALLING,
 458                                 pcf8563->rtc->name, client);
 459                 if (err) {
 460                         dev_err(&client->dev, "unable to request IRQ %d\n",
 461                                                                 client->irq);
 462                         return err;
 463                 }
 464
 465         }
 466
 467         /* the pcf8563 alarm only supports a minute accuracy */
 468         pcf8563->rtc->uie_unsupported = 1;
 469
 470         return 0;
 471 }
 472
 473 static const struct i2c_device_id pcf8563_id[] = {
 474         { "pcf8563", 0 },
 475         { "rtc8564", 0 },
 476         { }
 477 };
 478 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 479
 480 #ifdef CONFIG_OF
 481 static const struct of_device_id pcf8563_of_match[] = {
 482         { .compatible = "nxp,pcf8563" },
 483         {}
 484 };
 485 MODULE_DEVICE_TABLE(of, pcf8563_of_match);
 486 #endif
 487
 488 static struct i2c_driver pcf8563_driver = {
 489         .driver         = {
 490                 .name   = "rtc-pcf8563",
 491                 .owner  = THIS_MODULE,
 492                 .of_match_table = of_match_ptr(pcf8563_of_match),
 493         },
 494         .probe          = pcf8563_probe,
 495         .id_table       = pcf8563_id,
 496 };
 497
 498 module_i2c_driver(pcf8563_driver);
 499
 500 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 501 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 502 MODULE_LICENSE("GPL");
 503 MODULE_VERSION(DRV_VERSION);