drivers/rtc/rtc-ds1672.c

   1 /*
   2  * An rtc/i2c driver for the Dallas DS1672
   3  * Copyright 2005 Alessandro Zummo
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/i2c.h>
  12 #include <linux/rtc.h>
  13
  14 #define DRV_VERSION "0.2"
  15
  16 /* Addresses to scan: none. This chip cannot be detected. */
  17 static unsigned short normal_i2c[] = { I2C_CLIENT_END };
  18
  19 /* Insmod parameters */
  20 I2C_CLIENT_INSMOD;
  21
  22 /* Registers */
  23
  24 #define DS1672_REG_CNT_BASE     0
  25 #define DS1672_REG_CONTROL      4
  26 #define DS1672_REG_TRICKLE      5
  27
  28
  29 /* Prototypes */
  30 static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind);
  31
  32 /*
  33  * In the routines that deal directly with the ds1672 hardware, we use
  34  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
  35  * Epoch is initialized as 2000. Time is set to UTC.
  36  */
  37 static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  38 {
  39         unsigned long time;
  40         unsigned char addr = DS1672_REG_CNT_BASE;
  41         unsigned char buf[4];
  42
  43         struct i2c_msg msgs[] = {
  44                 { client->addr, 0, 1, &addr },          /* setup read ptr */
  45                 { client->addr, I2C_M_RD, 4, buf },     /* read date */
  46         };
  47
  48         /* read date registers */
  49         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
  50                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
  51                 return -EIO;
  52         }
  53
  54         dev_dbg(&client->dev,
  55                 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n"
  56                 __FUNCTION__,
  57                 buf[0], buf[1], buf[2], buf[3]);
  58
  59         time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
  60
  61         rtc_time_to_tm(time, tm);
  62
  63         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
  64                 "mday=%d, mon=%d, year=%d, wday=%d\n",
  65                 __FUNCTION__,
  66                 tm->tm_sec, tm->tm_min, tm->tm_hour,
  67                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
  68
  69         return 0;
  70 }
  71
  72 static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
  73 {
  74         int xfer;
  75         unsigned char buf[5];
  76
  77         buf[0] = DS1672_REG_CNT_BASE;
  78         buf[1] = secs & 0x000000FF;
  79         buf[2] = (secs & 0x0000FF00) >> 8;
  80         buf[3] = (secs & 0x00FF0000) >> 16;
  81         buf[4] = (secs & 0xFF000000) >> 24;
  82
  83         xfer = i2c_master_send(client, buf, 5);
  84         if (xfer != 5) {
  85                 dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer);
  86                 return -EIO;
  87         }
  88
  89         return 0;
  90 }
  91
  92 static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm)
  93 {
  94         unsigned long secs;
  95
  96         dev_dbg(&client->dev,
  97                 "%s: secs=%d, mins=%d, hours=%d, ",
  98                 "mday=%d, mon=%d, year=%d, wday=%d\n",
  99                 __FUNCTION__,
 100                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 101                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 102
 103         rtc_tm_to_time(tm, &secs);
 104
 105         return ds1672_set_mmss(client, secs);
 106 }
 107
 108 static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
 109 {
 110         return ds1672_get_datetime(to_i2c_client(dev), tm);
 111 }
 112
 113 static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm)
 114 {
 115         return ds1672_set_datetime(to_i2c_client(dev), tm);
 116 }
 117
 118 static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
 119 {
 120         return ds1672_set_mmss(to_i2c_client(dev), secs);
 121 }
 122
 123 static struct rtc_class_ops ds1672_rtc_ops = {
 124         .read_time      = ds1672_rtc_read_time,
 125         .set_time       = ds1672_rtc_set_time,
 126         .set_mmss       = ds1672_rtc_set_mmss,
 127 };
 128
 129 static int ds1672_attach(struct i2c_adapter *adapter)
 130 {
 131         dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
 132         return i2c_probe(adapter, &addr_data, ds1672_probe);
 133 }
 134
 135 static int ds1672_detach(struct i2c_client *client)
 136 {
 137         int err;
 138         struct rtc_device *rtc = i2c_get_clientdata(client);
 139
 140         dev_dbg(&client->dev, "%s\n", __FUNCTION__);
 141
 142         if (rtc)
 143                 rtc_device_unregister(rtc);
 144
 145         if ((err = i2c_detach_client(client)))
 146                 return err;
 147
 148         kfree(client);
 149
 150         return 0;
 151 }
 152
 153 static struct i2c_driver ds1672_driver = {
 154         .driver         = {
 155                 .name   = "ds1672",
 156         },
 157         .id             = I2C_DRIVERID_DS1672,
 158         .attach_adapter = &ds1672_attach,
 159         .detach_client  = &ds1672_detach,
 160 };
 161
 162 static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind)
 163 {
 164         int err = 0;
 165         struct i2c_client *client;
 166         struct rtc_device *rtc;
 167
 168         dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
 169
 170         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
 171                 err = -ENODEV;
 172                 goto exit;
 173         }
 174
 175         if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
 176                 err = -ENOMEM;
 177                 goto exit;
 178         }
 179
 180         /* I2C client */
 181         client->addr = address;
 182         client->driver = &ds1672_driver;
 183         client->adapter = adapter;
 184
 185         strlcpy(client->name, ds1672_driver.driver.name, I2C_NAME_SIZE);
 186
 187         /* Inform the i2c layer */
 188         if ((err = i2c_attach_client(client)))
 189                 goto exit_kfree;
 190
 191         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 192
 193         rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev,
 194                                 &ds1672_rtc_ops, THIS_MODULE);
 195
 196         if (IS_ERR(rtc)) {
 197                 err = PTR_ERR(rtc);
 198                 dev_err(&client->dev,
 199                         "unable to register the class device\n");
 200                 goto exit_detach;
 201         }
 202
 203         i2c_set_clientdata(client, rtc);
 204
 205         return 0;
 206
 207 exit_detach:
 208         i2c_detach_client(client);
 209
 210 exit_kfree:
 211         kfree(client);
 212
 213 exit:
 214         return err;
 215 }
 216
 217 static int __init ds1672_init(void)
 218 {
 219         return i2c_add_driver(&ds1672_driver);
 220 }
 221
 222 static void __exit ds1672_exit(void)
 223 {
 224         i2c_del_driver(&ds1672_driver);
 225 }
 226
 227 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 228 MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
 229 MODULE_LICENSE("GPL");
 230 MODULE_VERSION(DRV_VERSION);
 231
 232 module_init(ds1672_init);
 233 module_exit(ds1672_exit);