LXR linux/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
  46static struct i2c_driver pcf8563_driver;
  47
  48struct 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 */
  71static 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
 128static 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
 174struct pcf8563_limit
 175{
 176        unsigned char reg;
 177        unsigned char mask;
 178        unsigned char min;
 179        unsigned char max;
 180};
 181
 182static 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
 187static 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
 192static const struct rtc_class_ops pcf8563_rtc_ops = {
 193        .read_time      = pcf8563_rtc_read_time,
 194        .set_time       = pcf8563_rtc_set_time,
 195};
 196
 197static 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        pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
 216                                &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
 217
 218        if (IS_ERR(pcf8563->rtc)) {
 219                err = PTR_ERR(pcf8563->rtc);
 220                goto exit_kfree;
 221        }
 222
 223        i2c_set_clientdata(client, pcf8563);
 224
 225        return 0;
 226
 227exit_kfree:
 228        kfree(pcf8563);
 229
 230        return err;
 231}
 232
 233static 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
 245static const struct i2c_device_id pcf8563_id[] = {
 246        { "pcf8563", 0 },
 247        { "rtc8564", 0 },
 248        { }
 249};
 250MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 251
 252static 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
 261static int __init pcf8563_init(void)
 262{
 263        return i2c_add_driver(&pcf8563_driver);
 264}
 265
 266static void __exit pcf8563_exit(void)
 267{
 268        i2c_del_driver(&pcf8563_driver);
 269}
 270
 271MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 272MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 273MODULE_LICENSE("GPL");
 274MODULE_VERSION(DRV_VERSION);
 275
 276module_init(pcf8563_init);
 277module_exit(pcf8563_exit);
 278