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 #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
  48 static struct i2c_driver pcf8563_driver;
  49
  50 struct 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  */
  73 static 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
 130 static 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
 176 static 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
 181 static 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
 186 static const struct rtc_class_ops pcf8563_rtc_ops = {
 187         .read_time      = pcf8563_rtc_read_time,
 188         .set_time       = pcf8563_rtc_set_time,
 189 };
 190
 191 static 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
 221 exit_kfree:
 222         kfree(pcf8563);
 223
 224         return err;
 225 }
 226
 227 static 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
 239 static const struct i2c_device_id pcf8563_id[] = {
 240         { "pcf8563", 0 },
 241         { "rtc8564", 0 },
 242         { }
 243 };
 244 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
 245
 246 static 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
 255 static int __init pcf8563_init(void)
 256 {
 257         return i2c_add_driver(&pcf8563_driver);
 258 }
 259
 260 static void __exit pcf8563_exit(void)
 261 {
 262         i2c_del_driver(&pcf8563_driver);
 263 }
 264
 265 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 266 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 267 MODULE_LICENSE("GPL");
 268 MODULE_VERSION(DRV_VERSION);
 269
 270 module_init(pcf8563_init);
 271 module_exit(pcf8563_exit);