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_rtc_read_time(struct device *dev, struct rtc_time *tm)
 183 {
 184         return pcf8563_get_datetime(to_i2c_client(dev), tm);
 185 }
 186
 187 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 188 {
 189         return pcf8563_set_datetime(to_i2c_client(dev), tm);
 190 }
 191
 192 static const struct rtc_class_ops pcf8563_rtc_ops = {
 193         .read_time      = pcf8563_rtc_read_time,
 194         .set_time       = pcf8563_rtc_set_time,
 195 };
 196
 197 static int pcf8563_probe(struct i2c_client *client,
 198                                 const struct i2c_device_id *id)
 199 {
 200         struct pcf8563 *pcf8563;
 201
 202         int err = 0;
 203
 204         dev_dbg(&client->dev, "%s\n", __func__);
 205
 206         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 207                 return -ENODEV;
 208
 209         pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
 210         if (!pcf8563)
 211                 return -ENOMEM;
 212
 213         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 214
 215         i2c_set_clientdata(client, pcf8563);
 216
 217         pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
 218                                 &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
 219
 220         if (IS_ERR(pcf8563->rtc)) {
 221                 err = PTR_ERR(pcf8563->rtc);
 222                 goto exit_kfree;
 223         }
 224
 225         return 0;
 226
 227 exit_kfree:
 228         kfree(pcf8563);
 229
 230         return err;
 231 }
 232
 233 static int pcf8563_remove(struct i2c_client *client)
 234 {
 235         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 236
 237         if (pcf8563->rtc)
 238                 rtc_device_unregister(pcf8563->rtc);
 239
 240         kfree(pcf8563);
 241
 242         return 0;
 243 }
 244
 245 static const struct i2c_device_id pcf8563_id[] = {
 246         { "pcf8563", 0 },
 247         { "rtc8564", 0 },
 248         { }
 249 };
 250 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 251
 252 static struct i2c_driver pcf8563_driver = {
 253         .driver         = {
 254                 .name   = "rtc-pcf8563",
 255         },
 256         .probe          = pcf8563_probe,
 257         .remove         = pcf8563_remove,
 258         .id_table       = pcf8563_id,
 259 };
 260
 261 static int __init pcf8563_init(void)
 262 {
 263         return i2c_add_driver(&pcf8563_driver);
 264 }
 265
 266 static void __exit pcf8563_exit(void)
 267 {
 268         i2c_del_driver(&pcf8563_driver);
 269 }
 270
 271 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 272 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 273 MODULE_LICENSE("GPL");
 274 MODULE_VERSION(DRV_VERSION);
 275
 276 module_init(pcf8563_init);
 277 module_exit(pcf8563_exit);