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
  22 #define DRV_VERSION "0.4.3"
  23
  24 #define PCF8563_REG_ST1         0x00 /* status */
  25 #define PCF8563_REG_ST2         0x01
  26
  27 #define PCF8563_REG_SC          0x02 /* datetime */
  28 #define PCF8563_REG_MN          0x03
  29 #define PCF8563_REG_HR          0x04
  30 #define PCF8563_REG_DM          0x05
  31 #define PCF8563_REG_DW          0x06
  32 #define PCF8563_REG_MO          0x07
  33 #define PCF8563_REG_YR          0x08
  34
  35 #define PCF8563_REG_AMN         0x09 /* alarm */
  36 #define PCF8563_REG_AHR         0x0A
  37 #define PCF8563_REG_ADM         0x0B
  38 #define PCF8563_REG_ADW         0x0C
  39
  40 #define PCF8563_REG_CLKO        0x0D /* clock out */
  41 #define PCF8563_REG_TMRC        0x0E /* timer control */
  42 #define PCF8563_REG_TMR         0x0F /* timer */
  43
  44 #define PCF8563_SC_LV           0x80 /* low voltage */
  45 #define PCF8563_MO_C            0x80 /* century */
  46
  47 static struct i2c_driver pcf8563_driver;
  48
  49 struct pcf8563 {
  50         struct rtc_device *rtc;
  51         /*
  52          * The meaning of MO_C bit varies by the chip type.
  53          * From PCF8563 datasheet: this bit is toggled when the years
  54          * register overflows from 99 to 00
  55          *   0 indicates the century is 20xx
  56          *   1 indicates the century is 19xx
  57          * From RTC8564 datasheet: this bit indicates change of
  58          * century. When the year digit data overflows from 99 to 00,
  59          * this bit is set. By presetting it to 0 while still in the
  60          * 20th century, it will be set in year 2000, ...
  61          * There seems no reliable way to know how the system use this
  62          * bit.  So let's do it heuristically, assuming we are live in
  63          * 1970...2069.
  64          */
  65         int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
  66 };
  67
  68 /*
  69  * In the routines that deal directly with the pcf8563 hardware, we use
  70  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  71  */
  72 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  73 {
  74         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
  75         unsigned char buf[13] = { PCF8563_REG_ST1 };
  76
  77         struct i2c_msg msgs[] = {
  78                 { client->addr, 0, 1, buf },    /* setup read ptr */
  79                 { client->addr, I2C_M_RD, 13, buf },    /* read status + date */
  80         };
  81
  82         /* read registers */
  83         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  84                 dev_err(&client->dev, "%s: read error\n", __func__);
  85                 return -EIO;
  86         }
  87
  88         if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
  89                 dev_info(&client->dev,
  90                         "low voltage detected, date/time is not reliable.\n");
  91
  92         dev_dbg(&client->dev,
  93                 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
  94                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
  95                 __func__,
  96                 buf[0], buf[1], buf[2], buf[3],
  97                 buf[4], buf[5], buf[6], buf[7],
  98                 buf[8]);
  99
 100
 101         tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
 102         tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
 103         tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
 104         tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
 105         tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
 106         tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 107         tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
 108         if (tm->tm_year < 70)
 109                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
 110         /* detect the polarity heuristically. see note above. */
 111         pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
 112                 (tm->tm_year >= 100) : (tm->tm_year < 100);
 113
 114         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 115                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 116                 __func__,
 117                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 118                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 119
 120         /* the clock can give out invalid datetime, but we cannot return
 121          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
 122          */
 123         if (rtc_valid_tm(tm) < 0)
 124                 dev_err(&client->dev, "retrieved date/time is not valid.\n");
 125
 126         return 0;
 127 }
 128
 129 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 130 {
 131         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 132         int i, err;
 133         unsigned char buf[9];
 134
 135         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 136                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 137                 __func__,
 138                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 139                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 140
 141         /* hours, minutes and seconds */
 142         buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
 143         buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
 144         buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
 145
 146         buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
 147
 148         /* month, 1 - 12 */
 149         buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
 150
 151         /* year and century */
 152         buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
 153         if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
 154                 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
 155
 156         buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 157
 158         /* write register's data */
 159         for (i = 0; i < 7; i++) {
 160                 unsigned char data[2] = { PCF8563_REG_SC + i,
 161                                                 buf[PCF8563_REG_SC + i] };
 162
 163                 err = i2c_master_send(client, data, sizeof(data));
 164                 if (err != sizeof(data)) {
 165                         dev_err(&client->dev,
 166                                 "%s: err=%d addr=%02x, data=%02x\n",
 167                                 __func__, err, data[0], data[1]);
 168                         return -EIO;
 169                 }
 170         };
 171
 172         return 0;
 173 }
 174
 175 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 176 {
 177         return pcf8563_get_datetime(to_i2c_client(dev), tm);
 178 }
 179
 180 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 181 {
 182         return pcf8563_set_datetime(to_i2c_client(dev), tm);
 183 }
 184
 185 static const struct rtc_class_ops pcf8563_rtc_ops = {
 186         .read_time      = pcf8563_rtc_read_time,
 187         .set_time       = pcf8563_rtc_set_time,
 188 };
 189
 190 static int pcf8563_probe(struct i2c_client *client,
 191                                 const struct i2c_device_id *id)
 192 {
 193         struct pcf8563 *pcf8563;
 194
 195         int err = 0;
 196
 197         dev_dbg(&client->dev, "%s\n", __func__);
 198
 199         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 200                 return -ENODEV;
 201
 202         pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
 203         if (!pcf8563)
 204                 return -ENOMEM;
 205
 206         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 207
 208         i2c_set_clientdata(client, pcf8563);
 209
 210         pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
 211                                 &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
 212
 213         if (IS_ERR(pcf8563->rtc)) {
 214                 err = PTR_ERR(pcf8563->rtc);
 215                 goto exit_kfree;
 216         }
 217
 218         return 0;
 219
 220 exit_kfree:
 221         kfree(pcf8563);
 222
 223         return err;
 224 }
 225
 226 static int pcf8563_remove(struct i2c_client *client)
 227 {
 228         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 229
 230         if (pcf8563->rtc)
 231                 rtc_device_unregister(pcf8563->rtc);
 232
 233         kfree(pcf8563);
 234
 235         return 0;
 236 }
 237
 238 static const struct i2c_device_id pcf8563_id[] = {
 239         { "pcf8563", 0 },
 240         { "rtc8564", 0 },
 241         { }
 242 };
 243 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 244
 245 static struct i2c_driver pcf8563_driver = {
 246         .driver         = {
 247                 .name   = "rtc-pcf8563",
 248         },
 249         .probe          = pcf8563_probe,
 250         .remove         = pcf8563_remove,
 251         .id_table       = pcf8563_id,
 252 };
 253
 254 static int __init pcf8563_init(void)
 255 {
 256         return i2c_add_driver(&pcf8563_driver);
 257 }
 258
 259 static void __exit pcf8563_exit(void)
 260 {
 261         i2c_del_driver(&pcf8563_driver);
 262 }
 263
 264 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 265 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 266 MODULE_LICENSE("GPL");
 267 MODULE_VERSION(DRV_VERSION);
 268
 269 module_init(pcf8563_init);
 270 module_exit(pcf8563_exit);