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