linux/drivers/rtc/rtc-pcf8563.c
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   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#include <linux/module.h>
  22
  23#define DRV_VERSION "0.4.3"
  24
  25#define PCF8563_REG_ST1         0x00 /* status */
  26#define PCF8563_REG_ST2         0x01
  27
  28#define PCF8563_REG_SC          0x02 /* datetime */
  29#define PCF8563_REG_MN          0x03
  30#define PCF8563_REG_HR          0x04
  31#define PCF8563_REG_DM          0x05
  32#define PCF8563_REG_DW          0x06
  33#define PCF8563_REG_MO          0x07
  34#define PCF8563_REG_YR          0x08
  35
  36#define PCF8563_REG_AMN         0x09 /* alarm */
  37#define PCF8563_REG_AHR         0x0A
  38#define PCF8563_REG_ADM         0x0B
  39#define PCF8563_REG_ADW         0x0C
  40
  41#define PCF8563_REG_CLKO        0x0D /* clock out */
  42#define PCF8563_REG_TMRC        0x0E /* timer control */
  43#define PCF8563_REG_TMR         0x0F /* timer */
  44
  45#define PCF8563_SC_LV           0x80 /* low voltage */
  46#define PCF8563_MO_C            0x80 /* century */
  47
  48static struct i2c_driver pcf8563_driver;
  49
  50struct pcf8563 {
  51        struct rtc_device *rtc;
  52        /*
  53         * The meaning of MO_C bit varies by the chip type.
  54         * From PCF8563 datasheet: this bit is toggled when the years
  55         * register overflows from 99 to 00
  56         *   0 indicates the century is 20xx
  57         *   1 indicates the century is 19xx
  58         * From RTC8564 datasheet: this bit indicates change of
  59         * century. When the year digit data overflows from 99 to 00,
  60         * this bit is set. By presetting it to 0 while still in the
  61         * 20th century, it will be set in year 2000, ...
  62         * There seems no reliable way to know how the system use this
  63         * bit.  So let's do it heuristically, assuming we are live in
  64         * 1970...2069.
  65         */
  66        int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
  67};
  68
  69/*
  70 * In the routines that deal directly with the pcf8563 hardware, we use
  71 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  72 */
  73static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  74{
  75        struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
  76        unsigned char buf[13] = { PCF8563_REG_ST1 };
  77
  78        struct i2c_msg msgs[] = {
  79                { client->addr, 0, 1, buf },    /* setup read ptr */
  80                { client->addr, I2C_M_RD, 13, buf },    /* read status + date */
  81        };
  82
  83        /* read registers */
  84        if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  85                dev_err(&client->dev, "%s: read error\n", __func__);
  86                return -EIO;
  87        }
  88
  89        if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
  90                dev_info(&client->dev,
  91                        "low voltage detected, date/time is not reliable.\n");
  92
  93        dev_dbg(&client->dev,
  94                "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
  95                "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
  96                __func__,
  97                buf[0], buf[1], buf[2], buf[3],
  98                buf[4], buf[5], buf[6], buf[7],
  99                buf[8]);
 100
 101
 102        tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
 103        tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
 104        tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
 105        tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
 106        tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
 107        tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 108        tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
 109        if (tm->tm_year < 70)
 110                tm->tm_year += 100;     /* assume we are in 1970...2069 */
 111        /* detect the polarity heuristically. see note above. */
 112        pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
 113                (tm->tm_year >= 100) : (tm->tm_year < 100);
 114
 115        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 116                "mday=%d, mon=%d, year=%d, wday=%d\n",
 117                __func__,
 118                tm->tm_sec, tm->tm_min, tm->tm_hour,
 119                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 120
 121        /* the clock can give out invalid datetime, but we cannot return
 122         * -EINVAL otherwise hwclock will refuse to set the time on bootup.
 123         */
 124        if (rtc_valid_tm(tm) < 0)
 125                dev_err(&client->dev, "retrieved date/time is not valid.\n");
 126
 127        return 0;
 128}
 129
 130static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 131{
 132        struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 133        int i, err;
 134        unsigned char buf[9];
 135
 136        dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 137                "mday=%d, mon=%d, year=%d, wday=%d\n",
 138                __func__,
 139                tm->tm_sec, tm->tm_min, tm->tm_hour,
 140                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 141
 142        /* hours, minutes and seconds */
 143        buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
 144        buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
 145        buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
 146
 147        buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
 148
 149        /* month, 1 - 12 */
 150        buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
 151
 152        /* year and century */
 153        buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
 154        if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
 155                buf[PCF8563_REG_MO] |= PCF8563_MO_C;
 156
 157        buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 158
 159        /* write register's data */
 160        for (i = 0; i < 7; i++) {
 161                unsigned char data[2] = { PCF8563_REG_SC + i,
 162                                                buf[PCF8563_REG_SC + i] };
 163
 164                err = i2c_master_send(client, data, sizeof(data));
 165                if (err != sizeof(data)) {
 166                        dev_err(&client->dev,
 167                                "%s: err=%d addr=%02x, data=%02x\n",
 168                                __func__, err, data[0], data[1]);
 169                        return -EIO;
 170                }
 171        };
 172
 173        return 0;
 174}
 175
 176static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 177{
 178        return pcf8563_get_datetime(to_i2c_client(dev), tm);
 179}
 180
 181static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 182{
 183        return pcf8563_set_datetime(to_i2c_client(dev), tm);
 184}
 185
 186static const struct rtc_class_ops pcf8563_rtc_ops = {
 187        .read_time      = pcf8563_rtc_read_time,
 188        .set_time       = pcf8563_rtc_set_time,
 189};
 190
 191static int pcf8563_probe(struct i2c_client *client,
 192                                const struct i2c_device_id *id)
 193{
 194        struct pcf8563 *pcf8563;
 195
 196        int err = 0;
 197
 198        dev_dbg(&client->dev, "%s\n", __func__);
 199
 200        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 201                return -ENODEV;
 202
 203        pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
 204        if (!pcf8563)
 205                return -ENOMEM;
 206
 207        dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 208
 209        i2c_set_clientdata(client, pcf8563);
 210
 211        pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
 212                                &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
 213
 214        if (IS_ERR(pcf8563->rtc)) {
 215                err = PTR_ERR(pcf8563->rtc);
 216                goto exit_kfree;
 217        }
 218
 219        return 0;
 220
 221exit_kfree:
 222        kfree(pcf8563);
 223
 224        return err;
 225}
 226
 227static int pcf8563_remove(struct i2c_client *client)
 228{
 229        struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 230
 231        if (pcf8563->rtc)
 232                rtc_device_unregister(pcf8563->rtc);
 233
 234        kfree(pcf8563);
 235
 236        return 0;
 237}
 238
 239static const struct i2c_device_id pcf8563_id[] = {
 240        { "pcf8563", 0 },
 241        { "rtc8564", 0 },
 242        { }
 243};
 244MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 245
 246static struct i2c_driver pcf8563_driver = {
 247        .driver         = {
 248                .name   = "rtc-pcf8563",
 249        },
 250        .probe          = pcf8563_probe,
 251        .remove         = pcf8563_remove,
 252        .id_table       = pcf8563_id,
 253};
 254
 255static int __init pcf8563_init(void)
 256{
 257        return i2c_add_driver(&pcf8563_driver);
 258}
 259
 260static void __exit pcf8563_exit(void)
 261{
 262        i2c_del_driver(&pcf8563_driver);
 263}
 264
 265MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 266MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 267MODULE_LICENSE("GPL");
 268MODULE_VERSION(DRV_VERSION);
 269
 270module_init(pcf8563_init);
 271module_exit(pcf8563_exit);
 272