drivers/rtc/rtc-rs5c372.c

   1 /*
   2  * An I2C driver for the Ricoh RS5C372 RTC
   3  *
   4  * Copyright (C) 2005 Pavel Mironchik <pmironchik@optifacio.net>
   5  * Copyright (C) 2006 Tower Technologies
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/i2c.h>
  13 #include <linux/rtc.h>
  14 #include <linux/bcd.h>
  15
  16 #define DRV_VERSION "0.2"
  17
  18 /* Addresses to scan */
  19 static unsigned short normal_i2c[] = { /* 0x32,*/ I2C_CLIENT_END };
  20
  21 /* Insmod parameters */
  22 I2C_CLIENT_INSMOD;
  23
  24 #define RS5C372_REG_SECS        0
  25 #define RS5C372_REG_MINS        1
  26 #define RS5C372_REG_HOURS       2
  27 #define RS5C372_REG_WDAY        3
  28 #define RS5C372_REG_DAY         4
  29 #define RS5C372_REG_MONTH       5
  30 #define RS5C372_REG_YEAR        6
  31 #define RS5C372_REG_TRIM        7
  32
  33 #define RS5C372_TRIM_XSL        0x80
  34 #define RS5C372_TRIM_MASK       0x7F
  35
  36 #define RS5C372_REG_BASE        0
  37
  38 static int rs5c372_attach(struct i2c_adapter *adapter);
  39 static int rs5c372_detach(struct i2c_client *client);
  40 static int rs5c372_probe(struct i2c_adapter *adapter, int address, int kind);
  41
  42 static struct i2c_driver rs5c372_driver = {
  43         .driver         = {
  44                 .name   = "rs5c372",
  45         },
  46         .attach_adapter = &rs5c372_attach,
  47         .detach_client  = &rs5c372_detach,
  48 };
  49
  50 static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  51 {
  52         unsigned char buf[7] = { RS5C372_REG_BASE };
  53
  54         /* this implements the 1st reading method, according
  55          * to the datasheet. buf[0] is initialized with
  56          * address ptr and transmission format register.
  57          */
  58         struct i2c_msg msgs[] = {
  59                 { client->addr, 0, 1, buf },
  60                 { client->addr, I2C_M_RD, 7, buf },
  61         };
  62
  63         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  64                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
  65                 return -EIO;
  66         }
  67
  68         tm->tm_sec = BCD2BIN(buf[RS5C372_REG_SECS] & 0x7f);
  69         tm->tm_min = BCD2BIN(buf[RS5C372_REG_MINS] & 0x7f);
  70         tm->tm_hour = BCD2BIN(buf[RS5C372_REG_HOURS] & 0x3f);
  71         tm->tm_wday = BCD2BIN(buf[RS5C372_REG_WDAY] & 0x07);
  72         tm->tm_mday = BCD2BIN(buf[RS5C372_REG_DAY] & 0x3f);
  73
  74         /* tm->tm_mon is zero-based */
  75         tm->tm_mon = BCD2BIN(buf[RS5C372_REG_MONTH] & 0x1f) - 1;
  76
  77         /* year is 1900 + tm->tm_year */
  78         tm->tm_year = BCD2BIN(buf[RS5C372_REG_YEAR]) + 100;
  79
  80         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
  81                 "mday=%d, mon=%d, year=%d, wday=%d\n",
  82                 __FUNCTION__,
  83                 tm->tm_sec, tm->tm_min, tm->tm_hour,
  84                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
  85
  86         return 0;
  87 }
  88
  89 static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
  90 {
  91         unsigned char buf[8] = { RS5C372_REG_BASE };
  92
  93         dev_dbg(&client->dev,
  94                 "%s: secs=%d, mins=%d, hours=%d "
  95                 "mday=%d, mon=%d, year=%d, wday=%d\n",
  96                 __FUNCTION__, tm->tm_sec, tm->tm_min, tm->tm_hour,
  97                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
  98
  99         buf[1] = BIN2BCD(tm->tm_sec);
 100         buf[2] = BIN2BCD(tm->tm_min);
 101         buf[3] = BIN2BCD(tm->tm_hour);
 102         buf[4] = BIN2BCD(tm->tm_wday);
 103         buf[5] = BIN2BCD(tm->tm_mday);
 104         buf[6] = BIN2BCD(tm->tm_mon + 1);
 105         buf[7] = BIN2BCD(tm->tm_year - 100);
 106
 107         if ((i2c_master_send(client, buf, 8)) != 8) {
 108                 dev_err(&client->dev, "%s: write error\n", __FUNCTION__);
 109                 return -EIO;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
 116 {
 117         unsigned char buf = RS5C372_REG_TRIM;
 118
 119         struct i2c_msg msgs[] = {
 120                 { client->addr, 0, 1, &buf },
 121                 { client->addr, I2C_M_RD, 1, &buf },
 122         };
 123
 124         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
 125                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
 126                 return -EIO;
 127         }
 128
 129         dev_dbg(&client->dev, "%s: raw trim=%x\n", __FUNCTION__, *trim);
 130
 131         if (osc)
 132                 *osc = (buf & RS5C372_TRIM_XSL) ? 32000 : 32768;
 133
 134         if (trim)
 135                 *trim = buf & RS5C372_TRIM_MASK;
 136
 137         return 0;
 138 }
 139
 140 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
 141 {
 142         return rs5c372_get_datetime(to_i2c_client(dev), tm);
 143 }
 144
 145 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
 146 {
 147         return rs5c372_set_datetime(to_i2c_client(dev), tm);
 148 }
 149
 150 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
 151 {
 152         int err, osc, trim;
 153
 154         err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
 155         if (err == 0) {
 156                 seq_printf(seq, "%d.%03d KHz\n", osc / 1000, osc % 1000);
 157                 seq_printf(seq, "trim\t: %d\n", trim);
 158         }
 159
 160         return 0;
 161 }
 162
 163 static const struct rtc_class_ops rs5c372_rtc_ops = {
 164         .proc           = rs5c372_rtc_proc,
 165         .read_time      = rs5c372_rtc_read_time,
 166         .set_time       = rs5c372_rtc_set_time,
 167 };
 168
 169 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
 170                                 struct device_attribute *attr, char *buf)
 171 {
 172         int err, trim;
 173
 174         err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
 175         if (err)
 176                 return err;
 177
 178         return sprintf(buf, "0x%2x\n", trim);
 179 }
 180 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
 181
 182 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
 183                                 struct device_attribute *attr, char *buf)
 184 {
 185         int err, osc;
 186
 187         err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
 188         if (err)
 189                 return err;
 190
 191         return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
 192 }
 193 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
 194
 195 static int rs5c372_attach(struct i2c_adapter *adapter)
 196 {
 197         return i2c_probe(adapter, &addr_data, rs5c372_probe);
 198 }
 199
 200 static int rs5c372_probe(struct i2c_adapter *adapter, int address, int kind)
 201 {
 202         int err = 0;
 203         struct i2c_client *client;
 204         struct rtc_device *rtc;
 205
 206         dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
 207
 208         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
 209                 err = -ENODEV;
 210                 goto exit;
 211         }
 212
 213         if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
 214                 err = -ENOMEM;
 215                 goto exit;
 216         }
 217
 218         /* I2C client */
 219         client->addr = address;
 220         client->driver = &rs5c372_driver;
 221         client->adapter = adapter;
 222
 223         strlcpy(client->name, rs5c372_driver.driver.name, I2C_NAME_SIZE);
 224
 225         /* Inform the i2c layer */
 226         if ((err = i2c_attach_client(client)))
 227                 goto exit_kfree;
 228
 229         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 230
 231         rtc = rtc_device_register(rs5c372_driver.driver.name, &client->dev,
 232                                 &rs5c372_rtc_ops, THIS_MODULE);
 233
 234         if (IS_ERR(rtc)) {
 235                 err = PTR_ERR(rtc);
 236                 goto exit_detach;
 237         }
 238
 239         i2c_set_clientdata(client, rtc);
 240
 241         device_create_file(&client->dev, &dev_attr_trim);
 242         device_create_file(&client->dev, &dev_attr_osc);
 243
 244         return 0;
 245
 246 exit_detach:
 247         i2c_detach_client(client);
 248
 249 exit_kfree:
 250         kfree(client);
 251
 252 exit:
 253         return err;
 254 }
 255
 256 static int rs5c372_detach(struct i2c_client *client)
 257 {
 258         int err;
 259         struct rtc_device *rtc = i2c_get_clientdata(client);
 260
 261         if (rtc)
 262                 rtc_device_unregister(rtc);
 263
 264         if ((err = i2c_detach_client(client)))
 265                 return err;
 266
 267         kfree(client);
 268
 269         return 0;
 270 }
 271
 272 static __init int rs5c372_init(void)
 273 {
 274         return i2c_add_driver(&rs5c372_driver);
 275 }
 276
 277 static __exit void rs5c372_exit(void)
 278 {
 279         i2c_del_driver(&rs5c372_driver);
 280 }
 281
 282 module_init(rs5c372_init);
 283 module_exit(rs5c372_exit);
 284
 285 MODULE_AUTHOR(
 286                 "Pavel Mironchik <pmironchik@optifacio.net>, "
 287                 "Alessandro Zummo <a.zummo@towertech.it>");
 288 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
 289 MODULE_LICENSE("GPL");
 290 MODULE_VERSION(DRV_VERSION);