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 "0.4.3"
  22
  23 #define PCF8563_REG_ST1         0x00 /* status */
  24 #define PCF8563_REG_ST2         0x01
  25
  26 #define PCF8563_REG_SC          0x02 /* datetime */
  27 #define PCF8563_REG_MN          0x03
  28 #define PCF8563_REG_HR          0x04
  29 #define PCF8563_REG_DM          0x05
  30 #define PCF8563_REG_DW          0x06
  31 #define PCF8563_REG_MO          0x07
  32 #define PCF8563_REG_YR          0x08
  33
  34 #define PCF8563_REG_AMN         0x09 /* alarm */
  35 #define PCF8563_REG_AHR         0x0A
  36 #define PCF8563_REG_ADM         0x0B
  37 #define PCF8563_REG_ADW         0x0C
  38
  39 #define PCF8563_REG_CLKO        0x0D /* clock out */
  40 #define PCF8563_REG_TMRC        0x0E /* timer control */
  41 #define PCF8563_REG_TMR         0x0F /* timer */
  42
  43 #define PCF8563_SC_LV           0x80 /* low voltage */
  44 #define PCF8563_MO_C            0x80 /* century */
  45
  46 static struct i2c_driver pcf8563_driver;
  47
  48 struct pcf8563 {
  49         struct rtc_device *rtc;
  50         /*
  51          * The meaning of MO_C bit varies by the chip type.
  52          * From PCF8563 datasheet: this bit is toggled when the years
  53          * register overflows from 99 to 00
  54          *   0 indicates the century is 20xx
  55          *   1 indicates the century is 19xx
  56          * From RTC8564 datasheet: this bit indicates change of
  57          * century. When the year digit data overflows from 99 to 00,
  58          * this bit is set. By presetting it to 0 while still in the
  59          * 20th century, it will be set in year 2000, ...
  60          * There seems no reliable way to know how the system use this
  61          * bit.  So let's do it heuristically, assuming we are live in
  62          * 1970...2069.
  63          */
  64         int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
  65 };
  66
  67 /*
  68  * In the routines that deal directly with the pcf8563 hardware, we use
  69  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  70  */
  71 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  72 {
  73         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
  74         unsigned char buf[13] = { PCF8563_REG_ST1 };
  75
  76         struct i2c_msg msgs[] = {
  77                 { client->addr, 0, 1, buf },    /* setup read ptr */
  78                 { client->addr, I2C_M_RD, 13, buf },    /* read status + date */
  79         };
  80
  81         /* read registers */
  82         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  83                 dev_err(&client->dev, "%s: read error\n", __func__);
  84                 return -EIO;
  85         }
  86
  87         if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
  88                 dev_info(&client->dev,
  89                         "low voltage detected, date/time is not reliable.\n");
  90
  91         dev_dbg(&client->dev,
  92                 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
  93                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
  94                 __func__,
  95                 buf[0], buf[1], buf[2], buf[3],
  96                 buf[4], buf[5], buf[6], buf[7],
  97                 buf[8]);
  98
  99
 100         tm->tm_sec = BCD2BIN(buf[PCF8563_REG_SC] & 0x7F);
 101         tm->tm_min = BCD2BIN(buf[PCF8563_REG_MN] & 0x7F);
 102         tm->tm_hour = BCD2BIN(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
 103         tm->tm_mday = BCD2BIN(buf[PCF8563_REG_DM] & 0x3F);
 104         tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
 105         tm->tm_mon = BCD2BIN(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 106         tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR]);
 107         if (tm->tm_year < 70)
 108                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
 109         /* detect the polarity heuristically. see note above. */
 110         pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
 111                 (tm->tm_year >= 100) : (tm->tm_year < 100);
 112
 113         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 114                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 115                 __func__,
 116                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 117                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 118
 119         /* the clock can give out invalid datetime, but we cannot return
 120          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
 121          */
 122         if (rtc_valid_tm(tm) < 0)
 123                 dev_err(&client->dev, "retrieved date/time is not valid.\n");
 124
 125         return 0;
 126 }
 127
 128 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 129 {
 130         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 131         int i, err;
 132         unsigned char buf[9];
 133
 134         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 135                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 136                 __func__,
 137                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 138                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 139
 140         /* hours, minutes and seconds */
 141         buf[PCF8563_REG_SC] = BIN2BCD(tm->tm_sec);
 142         buf[PCF8563_REG_MN] = BIN2BCD(tm->tm_min);
 143         buf[PCF8563_REG_HR] = BIN2BCD(tm->tm_hour);
 144
 145         buf[PCF8563_REG_DM] = BIN2BCD(tm->tm_mday);
 146
 147         /* month, 1 - 12 */
 148         buf[PCF8563_REG_MO] = BIN2BCD(tm->tm_mon + 1);
 149
 150         /* year and century */
 151         buf[PCF8563_REG_YR] = BIN2BCD(tm->tm_year % 100);
 152         if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
 153                 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
 154
 155         buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 156
 157         /* write register's data */
 158         for (i = 0; i < 7; i++) {
 159                 unsigned char data[2] = { PCF8563_REG_SC + i,
 160                                                 buf[PCF8563_REG_SC + i] };
 161
 162                 err = i2c_master_send(client, data, sizeof(data));
 163                 if (err != sizeof(data)) {
 164                         dev_err(&client->dev,
 165                                 "%s: err=%d addr=%02x, data=%02x\n",
 166                                 __func__, err, data[0], data[1]);
 167                         return -EIO;
 168                 }
 169         };
 170
 171         return 0;
 172 }
 173
 174 struct pcf8563_limit
 175 {
 176         unsigned char reg;
 177         unsigned char mask;
 178         unsigned char min;
 179         unsigned char max;
 180 };
 181
 182 static int pcf8563_validate_client(struct i2c_client *client)
 183 {
 184         int i;
 185
 186         static const struct pcf8563_limit pattern[] = {
 187                 /* register, mask, min, max */
 188                 { PCF8563_REG_SC,       0x7F,   0,      59      },
 189                 { PCF8563_REG_MN,       0x7F,   0,      59      },
 190                 { PCF8563_REG_HR,       0x3F,   0,      23      },
 191                 { PCF8563_REG_DM,       0x3F,   0,      31      },
 192                 { PCF8563_REG_MO,       0x1F,   0,      12      },
 193         };
 194
 195         /* check limits (only registers with bcd values) */
 196         for (i = 0; i < ARRAY_SIZE(pattern); i++) {
 197                 int xfer;
 198                 unsigned char value;
 199                 unsigned char buf = pattern[i].reg;
 200
 201                 struct i2c_msg msgs[] = {
 202                         { client->addr, 0, 1, &buf },
 203                         { client->addr, I2C_M_RD, 1, &buf },
 204                 };
 205
 206                 xfer = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 207
 208                 if (xfer != ARRAY_SIZE(msgs)) {
 209                         dev_err(&client->dev,
 210                                 "%s: could not read register 0x%02X\n",
 211                                 __func__, pattern[i].reg);
 212
 213                         return -EIO;
 214                 }
 215
 216                 value = BCD2BIN(buf & pattern[i].mask);
 217
 218                 if (value > pattern[i].max ||
 219                         value < pattern[i].min) {
 220                         dev_dbg(&client->dev,
 221                                 "%s: pattern=%d, reg=%x, mask=0x%02x, min=%d, "
 222                                 "max=%d, value=%d, raw=0x%02X\n",
 223                                 __func__, i, pattern[i].reg, pattern[i].mask,
 224                                 pattern[i].min, pattern[i].max,
 225                                 value, buf);
 226
 227                         return -ENODEV;
 228                 }
 229         }
 230
 231         return 0;
 232 }
 233
 234 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 235 {
 236         return pcf8563_get_datetime(to_i2c_client(dev), tm);
 237 }
 238
 239 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 240 {
 241         return pcf8563_set_datetime(to_i2c_client(dev), tm);
 242 }
 243
 244 static const struct rtc_class_ops pcf8563_rtc_ops = {
 245         .read_time      = pcf8563_rtc_read_time,
 246         .set_time       = pcf8563_rtc_set_time,
 247 };
 248
 249 static int pcf8563_probe(struct i2c_client *client,
 250                                 const struct i2c_device_id *id)
 251 {
 252         struct pcf8563 *pcf8563;
 253
 254         int err = 0;
 255
 256         dev_dbg(&client->dev, "%s\n", __func__);
 257
 258         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 259                 return -ENODEV;
 260
 261         pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
 262         if (!pcf8563)
 263                 return -ENOMEM;
 264
 265         /* Verify the chip is really an PCF8563 */
 266         if (pcf8563_validate_client(client) < 0) {
 267                 err = -ENODEV;
 268                 goto exit_kfree;
 269         }
 270
 271         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 272
 273         pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
 274                                 &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
 275
 276         if (IS_ERR(pcf8563->rtc)) {
 277                 err = PTR_ERR(pcf8563->rtc);
 278                 goto exit_kfree;
 279         }
 280
 281         i2c_set_clientdata(client, pcf8563);
 282
 283         return 0;
 284
 285 exit_kfree:
 286         kfree(pcf8563);
 287
 288         return err;
 289 }
 290
 291 static int pcf8563_remove(struct i2c_client *client)
 292 {
 293         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 294
 295         if (pcf8563->rtc)
 296                 rtc_device_unregister(pcf8563->rtc);
 297
 298         kfree(pcf8563);
 299
 300         return 0;
 301 }
 302
 303 static const struct i2c_device_id pcf8563_id[] = {
 304         { "pcf8563", 0 },
 305         { }
 306 };
 307 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 308
 309 static struct i2c_driver pcf8563_driver = {
 310         .driver         = {
 311                 .name   = "rtc-pcf8563",
 312         },
 313         .probe          = pcf8563_probe,
 314         .remove         = pcf8563_remove,
 315         .id_table       = pcf8563_id,
 316 };
 317
 318 static int __init pcf8563_init(void)
 319 {
 320         return i2c_add_driver(&pcf8563_driver);
 321 }
 322
 323 static void __exit pcf8563_exit(void)
 324 {
 325         i2c_del_driver(&pcf8563_driver);
 326 }
 327
 328 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 329 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 330 MODULE_LICENSE("GPL");
 331 MODULE_VERSION(DRV_VERSION);
 332
 333 module_init(pcf8563_init);
 334 module_exit(pcf8563_exit);