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#include <linux/of.h>
  23
  24#define DRV_VERSION "0.4.3"
  25
  26#define PCF8563_REG_ST1         0x00 /* status */
  27#define PCF8563_REG_ST2         0x01
  28
  29#define PCF8563_REG_SC          0x02 /* datetime */
  30#define PCF8563_REG_MN          0x03
  31#define PCF8563_REG_HR          0x04
  32#define PCF8563_REG_DM          0x05
  33#define PCF8563_REG_DW          0x06
  34#define PCF8563_REG_MO          0x07
  35#define PCF8563_REG_YR          0x08
  36
  37#define PCF8563_REG_AMN         0x09 /* alarm */
  38#define PCF8563_REG_AHR         0x0A
  39#define PCF8563_REG_ADM         0x0B
  40#define PCF8563_REG_ADW         0x0C
  41
  42#define PCF8563_REG_CLKO        0x0D /* clock out */
  43#define PCF8563_REG_TMRC        0x0E /* timer control */
  44#define PCF8563_REG_TMR         0x0F /* timer */
  45
  46#define PCF8563_SC_LV           0x80 /* low voltage */
  47#define PCF8563_MO_C            0x80 /* century */
  48
  49static struct i2c_driver pcf8563_driver;
  50
  51struct pcf8563 {
  52        struct rtc_device *rtc;
  53        /*
  54         * The meaning of MO_C bit varies by the chip type.
  55         * From PCF8563 datasheet: this bit is toggled when the years
  56         * register overflows from 99 to 00
  57         *   0 indicates the century is 20xx
  58         *   1 indicates the century is 19xx
  59         * From RTC8564 datasheet: this bit indicates change of
  60         * century. When the year digit data overflows from 99 to 00,
  61         * this bit is set. By presetting it to 0 while still in the
  62         * 20th century, it will be set in year 2000, ...
  63         * There seems no reliable way to know how the system use this
  64         * bit.  So let's do it heuristically, assuming we are live in
  65         * 1970...2069.
  66         */
  67        int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
  68        int voltage_low; /* incicates if a low_voltage was detected */
  69};
  70
  71/*
  72 * In the routines that deal directly with the pcf8563 hardware, we use
  73 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  74 */
  75static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  76{
  77        struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
  78        unsigned char buf[13] = { PCF8563_REG_ST1 };
  79
  80        struct i2c_msg msgs[] = {
  81                { client->addr, 0, 1, buf },    /* setup read ptr */
  82                { client->addr, I2C_M_RD, 13, buf },    /* read status + date */
  83        };
  84
  85        /* read registers */
  86        if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  87                dev_err(&client->dev, "%s: read error\n", __func__);
  88                return -EIO;
  89        }
  90
  91        if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
  92                pcf8563->voltage_low = 1;
  93                dev_info(&client->dev,
  94                        "low voltage detected, date/time is not reliable.\n");
  95        }
  96
  97        dev_dbg(&client->dev,
  98                "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
  99                "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
 100                __func__,
 101                buf[0], buf[1], buf[2], buf[3],
 102                buf[4], buf[5], buf[6], buf[7],
 103                buf[8]);
 104
 105
 106        tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
 107        tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
 108        tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
 109        tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
 110        tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
 111        tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 112        tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
 113        if (tm->tm_year < 70)
 114                tm->tm_year += 100;     /* assume we are in 1970...2069 */
 115        /* detect the polarity heuristically. see note above. */
 116        pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
 117                (tm->tm_year >= 100) : (tm->tm_year < 100);
 118
 119        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 120                "mday=%d, mon=%d, year=%d, wday=%d\n",
 121                __func__,
 122                tm->tm_sec, tm->tm_min, tm->tm_hour,
 123                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 124
 125        /* the clock can give out invalid datetime, but we cannot return
 126         * -EINVAL otherwise hwclock will refuse to set the time on bootup.
 127         */
 128        if (rtc_valid_tm(tm) < 0)
 129                dev_err(&client->dev, "retrieved date/time is not valid.\n");
 130
 131        return 0;
 132}
 133
 134static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 135{
 136        struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 137        int i, err;
 138        unsigned char buf[9];
 139
 140        dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 141                "mday=%d, mon=%d, year=%d, wday=%d\n",
 142                __func__,
 143                tm->tm_sec, tm->tm_min, tm->tm_hour,
 144                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 145
 146        /* hours, minutes and seconds */
 147        buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
 148        buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
 149        buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
 150
 151        buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
 152
 153        /* month, 1 - 12 */
 154        buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
 155
 156        /* year and century */
 157        buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
 158        if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
 159                buf[PCF8563_REG_MO] |= PCF8563_MO_C;
 160
 161        buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 162
 163        /* write register's data */
 164        for (i = 0; i < 7; i++) {
 165                unsigned char data[2] = { PCF8563_REG_SC + i,
 166                                                buf[PCF8563_REG_SC + i] };
 167
 168                err = i2c_master_send(client, data, sizeof(data));
 169                if (err != sizeof(data)) {
 170                        dev_err(&client->dev,
 171                                "%s: err=%d addr=%02x, data=%02x\n",
 172                                __func__, err, data[0], data[1]);
 173                        return -EIO;
 174                }
 175        };
 176
 177        return 0;
 178}
 179
 180#ifdef CONFIG_RTC_INTF_DEV
 181static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 182{
 183        struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
 184        struct rtc_time tm;
 185
 186        switch (cmd) {
 187        case RTC_VL_READ:
 188                if (pcf8563->voltage_low)
 189                        dev_info(dev, "low voltage detected, date/time is not reliable.\n");
 190
 191                if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
 192                                        sizeof(int)))
 193                        return -EFAULT;
 194                return 0;
 195        case RTC_VL_CLR:
 196                /*
 197                 * Clear the VL bit in the seconds register in case
 198                 * the time has not been set already (which would
 199                 * have cleared it). This does not really matter
 200                 * because of the cached voltage_low value but do it
 201                 * anyway for consistency.
 202                 */
 203                if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
 204                        pcf8563_set_datetime(to_i2c_client(dev), &tm);
 205
 206                /* Clear the cached value. */
 207                pcf8563->voltage_low = 0;
 208
 209                return 0;
 210        default:
 211                return -ENOIOCTLCMD;
 212        }
 213}
 214#else
 215#define pcf8563_rtc_ioctl NULL
 216#endif
 217
 218static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 219{
 220        return pcf8563_get_datetime(to_i2c_client(dev), tm);
 221}
 222
 223static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 224{
 225        return pcf8563_set_datetime(to_i2c_client(dev), tm);
 226}
 227
 228static const struct rtc_class_ops pcf8563_rtc_ops = {
 229        .ioctl          = pcf8563_rtc_ioctl,
 230        .read_time      = pcf8563_rtc_read_time,
 231        .set_time       = pcf8563_rtc_set_time,
 232};
 233
 234static int pcf8563_probe(struct i2c_client *client,
 235                                const struct i2c_device_id *id)
 236{
 237        struct pcf8563 *pcf8563;
 238
 239        int err = 0;
 240
 241        dev_dbg(&client->dev, "%s\n", __func__);
 242
 243        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 244                return -ENODEV;
 245
 246        pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
 247        if (!pcf8563)
 248                return -ENOMEM;
 249
 250        dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 251
 252        i2c_set_clientdata(client, pcf8563);
 253
 254        pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
 255                                &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
 256
 257        if (IS_ERR(pcf8563->rtc)) {
 258                err = PTR_ERR(pcf8563->rtc);
 259                goto exit_kfree;
 260        }
 261
 262        return 0;
 263
 264exit_kfree:
 265        kfree(pcf8563);
 266
 267        return err;
 268}
 269
 270static int pcf8563_remove(struct i2c_client *client)
 271{
 272        struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
 273
 274        if (pcf8563->rtc)
 275                rtc_device_unregister(pcf8563->rtc);
 276
 277        kfree(pcf8563);
 278
 279        return 0;
 280}
 281
 282static const struct i2c_device_id pcf8563_id[] = {
 283        { "pcf8563", 0 },
 284        { "rtc8564", 0 },
 285        { }
 286};
 287MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 288
 289#ifdef CONFIG_OF
 290static const struct of_device_id pcf8563_of_match[] __devinitconst = {
 291        { .compatible = "nxp,pcf8563" },
 292        {}
 293};
 294MODULE_DEVICE_TABLE(of, pcf8563_of_match);
 295#endif
 296
 297static struct i2c_driver pcf8563_driver = {
 298        .driver         = {
 299                .name   = "rtc-pcf8563",
 300                .owner  = THIS_MODULE,
 301                .of_match_table = of_match_ptr(pcf8563_of_match),
 302        },
 303        .probe          = pcf8563_probe,
 304        .remove         = pcf8563_remove,
 305        .id_table       = pcf8563_id,
 306};
 307
 308module_i2c_driver(pcf8563_driver);
 309
 310MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 311MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 312MODULE_LICENSE("GPL");
 313MODULE_VERSION(DRV_VERSION);
 314
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