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
  21 #define DRV_VERSION "0.4.2"
  22
  23 /* Addresses to scan: none
  24  * This chip cannot be reliably autodetected. An empty eeprom
  25  * located at 0x51 will pass the validation routine due to
  26  * the way the registers are implemented.
  27  */
  28 static unsigned short normal_i2c[] = { I2C_CLIENT_END };
  29
  30 /* Module parameters */
  31 I2C_CLIENT_INSMOD;
  32
  33 #define PCF8563_REG_ST1         0x00 /* status */
  34 #define PCF8563_REG_ST2         0x01
  35
  36 #define PCF8563_REG_SC          0x02 /* datetime */
  37 #define PCF8563_REG_MN          0x03
  38 #define PCF8563_REG_HR          0x04
  39 #define PCF8563_REG_DM          0x05
  40 #define PCF8563_REG_DW          0x06
  41 #define PCF8563_REG_MO          0x07
  42 #define PCF8563_REG_YR          0x08
  43
  44 #define PCF8563_REG_AMN         0x09 /* alarm */
  45 #define PCF8563_REG_AHR         0x0A
  46 #define PCF8563_REG_ADM         0x0B
  47 #define PCF8563_REG_ADW         0x0C
  48
  49 #define PCF8563_REG_CLKO        0x0D /* clock out */
  50 #define PCF8563_REG_TMRC        0x0E /* timer control */
  51 #define PCF8563_REG_TMR         0x0F /* timer */
  52
  53 #define PCF8563_SC_LV           0x80 /* low voltage */
  54 #define PCF8563_MO_C            0x80 /* century */
  55
  56 struct pcf8563 {
  57         struct i2c_client client;
  58         /*
  59          * The meaning of MO_C bit varies by the chip type.
  60          * From PCF8563 datasheet: this bit is toggled when the years
  61          * register overflows from 99 to 00
  62          *   0 indicates the century is 20xx
  63          *   1 indicates the century is 19xx
  64          * From RTC8564 datasheet: this bit indicates change of
  65          * century. When the year digit data overflows from 99 to 00,
  66          * this bit is set. By presetting it to 0 while still in the
  67          * 20th century, it will be set in year 2000, ...
  68          * There seems no reliable way to know how the system use this
  69          * bit.  So let's do it heuristically, assuming we are live in
  70          * 1970...2069.
  71          */
  72         int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
  73 };
  74
  75 static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind);
  76 static int pcf8563_detach(struct i2c_client *client);
  77
  78 /*
  79  * In the routines that deal directly with the pcf8563 hardware, we use
  80  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  81  */
  82 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  83 {
  84         struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client);
  85         unsigned char buf[13] = { PCF8563_REG_ST1 };
  86
  87         struct i2c_msg msgs[] = {
  88                 { client->addr, 0, 1, buf },    /* setup read ptr */
  89                 { client->addr, I2C_M_RD, 13, buf },    /* read status + date */
  90         };
  91
  92         /* read registers */
  93         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  94                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
  95                 return -EIO;
  96         }
  97
  98         if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
  99                 dev_info(&client->dev,
 100                         "low voltage detected, date/time is not reliable.\n");
 101
 102         dev_dbg(&client->dev,
 103                 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
 104                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
 105                 __FUNCTION__,
 106                 buf[0], buf[1], buf[2], buf[3],
 107                 buf[4], buf[5], buf[6], buf[7],
 108                 buf[8]);
 109
 110
 111         tm->tm_sec = BCD2BIN(buf[PCF8563_REG_SC] & 0x7F);
 112         tm->tm_min = BCD2BIN(buf[PCF8563_REG_MN] & 0x7F);
 113         tm->tm_hour = BCD2BIN(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
 114         tm->tm_mday = BCD2BIN(buf[PCF8563_REG_DM] & 0x3F);
 115         tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
 116         tm->tm_mon = BCD2BIN(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 117         tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR]);
 118         if (tm->tm_year < 70)
 119                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
 120         /* detect the polarity heuristically. see note above. */
 121         pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
 122                 (tm->tm_year >= 100) : (tm->tm_year < 100);
 123
 124         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 125                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 126                 __FUNCTION__,
 127                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 128                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 129
 130         /* the clock can give out invalid datetime, but we cannot return
 131          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
 132          */
 133         if (rtc_valid_tm(tm) < 0)
 134                 dev_err(&client->dev, "retrieved date/time is not valid.\n");
 135
 136         return 0;
 137 }
 138
 139 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 140 {
 141         struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client);
 142         int i, err;
 143         unsigned char buf[9];
 144
 145         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 146                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 147                 __FUNCTION__,
 148                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 149                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 150
 151         /* hours, minutes and seconds */
 152         buf[PCF8563_REG_SC] = BIN2BCD(tm->tm_sec);
 153         buf[PCF8563_REG_MN] = BIN2BCD(tm->tm_min);
 154         buf[PCF8563_REG_HR] = BIN2BCD(tm->tm_hour);
 155
 156         buf[PCF8563_REG_DM] = BIN2BCD(tm->tm_mday);
 157
 158         /* month, 1 - 12 */
 159         buf[PCF8563_REG_MO] = BIN2BCD(tm->tm_mon + 1);
 160
 161         /* year and century */
 162         buf[PCF8563_REG_YR] = BIN2BCD(tm->tm_year % 100);
 163         if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
 164                 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
 165
 166         buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 167
 168         /* write register's data */
 169         for (i = 0; i < 7; i++) {
 170                 unsigned char data[2] = { PCF8563_REG_SC + i,
 171                                                 buf[PCF8563_REG_SC + i] };
 172
 173                 err = i2c_master_send(client, data, sizeof(data));
 174                 if (err != sizeof(data)) {
 175                         dev_err(&client->dev,
 176                                 "%s: err=%d addr=%02x, data=%02x\n",
 177                                 __FUNCTION__, err, data[0], data[1]);
 178                         return -EIO;
 179                 }
 180         };
 181
 182         return 0;
 183 }
 184
 185 struct pcf8563_limit
 186 {
 187         unsigned char reg;
 188         unsigned char mask;
 189         unsigned char min;
 190         unsigned char max;
 191 };
 192
 193 static int pcf8563_validate_client(struct i2c_client *client)
 194 {
 195         int i;
 196
 197         static const struct pcf8563_limit pattern[] = {
 198                 /* register, mask, min, max */
 199                 { PCF8563_REG_SC,       0x7F,   0,      59      },
 200                 { PCF8563_REG_MN,       0x7F,   0,      59      },
 201                 { PCF8563_REG_HR,       0x3F,   0,      23      },
 202                 { PCF8563_REG_DM,       0x3F,   0,      31      },
 203                 { PCF8563_REG_MO,       0x1F,   0,      12      },
 204         };
 205
 206         /* check limits (only registers with bcd values) */
 207         for (i = 0; i < ARRAY_SIZE(pattern); i++) {
 208                 int xfer;
 209                 unsigned char value;
 210                 unsigned char buf = pattern[i].reg;
 211
 212                 struct i2c_msg msgs[] = {
 213                         { client->addr, 0, 1, &buf },
 214                         { client->addr, I2C_M_RD, 1, &buf },
 215                 };
 216
 217                 xfer = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 218
 219                 if (xfer != ARRAY_SIZE(msgs)) {
 220                         dev_err(&client->dev,
 221                                 "%s: could not read register 0x%02X\n",
 222                                 __FUNCTION__, pattern[i].reg);
 223
 224                         return -EIO;
 225                 }
 226
 227                 value = BCD2BIN(buf & pattern[i].mask);
 228
 229                 if (value > pattern[i].max ||
 230                         value < pattern[i].min) {
 231                         dev_dbg(&client->dev,
 232                                 "%s: pattern=%d, reg=%x, mask=0x%02x, min=%d, "
 233                                 "max=%d, value=%d, raw=0x%02X\n",
 234                                 __FUNCTION__, i, pattern[i].reg, pattern[i].mask,
 235                                 pattern[i].min, pattern[i].max,
 236                                 value, buf);
 237
 238                         return -ENODEV;
 239                 }
 240         }
 241
 242         return 0;
 243 }
 244
 245 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 246 {
 247         return pcf8563_get_datetime(to_i2c_client(dev), tm);
 248 }
 249
 250 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 251 {
 252         return pcf8563_set_datetime(to_i2c_client(dev), tm);
 253 }
 254
 255 static const struct rtc_class_ops pcf8563_rtc_ops = {
 256         .read_time      = pcf8563_rtc_read_time,
 257         .set_time       = pcf8563_rtc_set_time,
 258 };
 259
 260 static int pcf8563_attach(struct i2c_adapter *adapter)
 261 {
 262         return i2c_probe(adapter, &addr_data, pcf8563_probe);
 263 }
 264
 265 static struct i2c_driver pcf8563_driver = {
 266         .driver         = {
 267                 .name   = "pcf8563",
 268         },
 269         .id             = I2C_DRIVERID_PCF8563,
 270         .attach_adapter = &pcf8563_attach,
 271         .detach_client  = &pcf8563_detach,
 272 };
 273
 274 static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind)
 275 {
 276         struct pcf8563 *pcf8563;
 277         struct i2c_client *client;
 278         struct rtc_device *rtc;
 279
 280         int err = 0;
 281
 282         dev_dbg(adapter->class_dev.dev, "%s\n", __FUNCTION__);
 283
 284         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
 285                 err = -ENODEV;
 286                 goto exit;
 287         }
 288
 289         if (!(pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL))) {
 290                 err = -ENOMEM;
 291                 goto exit;
 292         }
 293
 294         client = &pcf8563->client;
 295         client->addr = address;
 296         client->driver = &pcf8563_driver;
 297         client->adapter = adapter;
 298
 299         strlcpy(client->name, pcf8563_driver.driver.name, I2C_NAME_SIZE);
 300
 301         /* Verify the chip is really an PCF8563 */
 302         if (kind < 0) {
 303                 if (pcf8563_validate_client(client) < 0) {
 304                         err = -ENODEV;
 305                         goto exit_kfree;
 306                 }
 307         }
 308
 309         /* Inform the i2c layer */
 310         if ((err = i2c_attach_client(client)))
 311                 goto exit_kfree;
 312
 313         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 314
 315         rtc = rtc_device_register(pcf8563_driver.driver.name, &client->dev,
 316                                 &pcf8563_rtc_ops, THIS_MODULE);
 317
 318         if (IS_ERR(rtc)) {
 319                 err = PTR_ERR(rtc);
 320                 goto exit_detach;
 321         }
 322
 323         i2c_set_clientdata(client, rtc);
 324
 325         return 0;
 326
 327 exit_detach:
 328         i2c_detach_client(client);
 329
 330 exit_kfree:
 331         kfree(pcf8563);
 332
 333 exit:
 334         return err;
 335 }
 336
 337 static int pcf8563_detach(struct i2c_client *client)
 338 {
 339         struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client);
 340         int err;
 341         struct rtc_device *rtc = i2c_get_clientdata(client);
 342
 343         if (rtc)
 344                 rtc_device_unregister(rtc);
 345
 346         if ((err = i2c_detach_client(client)))
 347                 return err;
 348
 349         kfree(pcf8563);
 350
 351         return 0;
 352 }
 353
 354 static int __init pcf8563_init(void)
 355 {
 356         return i2c_add_driver(&pcf8563_driver);
 357 }
 358
 359 static void __exit pcf8563_exit(void)
 360 {
 361         i2c_del_driver(&pcf8563_driver);
 362 }
 363
 364 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 365 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 366 MODULE_LICENSE("GPL");
 367 MODULE_VERSION(DRV_VERSION);
 368
 369 module_init(pcf8563_init);
 370 module_exit(pcf8563_exit);