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
  21 #define DRV_VERSION "0.4.2"
  22
  23 /* Addresses to scan: none
  24  * This chip cannot be reliably autodetected. An empty eeprom
  25  * located at 0x51 will pass the validation routine due to
  26  * the way the registers are implemented.
  27  */
  28 static unsigned short normal_i2c[] = { I2C_CLIENT_END };
  29
  30 /* Module parameters */
  31 I2C_CLIENT_INSMOD;
  32
  33 #define PCF8563_REG_ST1         0x00 /* status */
  34 #define PCF8563_REG_ST2         0x01
  35
  36 #define PCF8563_REG_SC          0x02 /* datetime */
  37 #define PCF8563_REG_MN          0x03
  38 #define PCF8563_REG_HR          0x04
  39 #define PCF8563_REG_DM          0x05
  40 #define PCF8563_REG_DW          0x06
  41 #define PCF8563_REG_MO          0x07
  42 #define PCF8563_REG_YR          0x08
  43
  44 #define PCF8563_REG_AMN         0x09 /* alarm */
  45 #define PCF8563_REG_AHR         0x0A
  46 #define PCF8563_REG_ADM         0x0B
  47 #define PCF8563_REG_ADW         0x0C
  48
  49 #define PCF8563_REG_CLKO        0x0D /* clock out */
  50 #define PCF8563_REG_TMRC        0x0E /* timer control */
  51 #define PCF8563_REG_TMR         0x0F /* timer */
  52
  53 #define PCF8563_SC_LV           0x80 /* low voltage */
  54 #define PCF8563_MO_C            0x80 /* century */
  55
  56 static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind);
  57 static int pcf8563_detach(struct i2c_client *client);
  58
  59 /*
  60  * In the routines that deal directly with the pcf8563 hardware, we use
  61  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  62  */
  63 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
  64 {
  65         unsigned char buf[13] = { PCF8563_REG_ST1 };
  66
  67         struct i2c_msg msgs[] = {
  68                 { client->addr, 0, 1, buf },    /* setup read ptr */
  69                 { client->addr, I2C_M_RD, 13, buf },    /* read status + date */
  70         };
  71
  72         /* read registers */
  73         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
  74                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
  75                 return -EIO;
  76         }
  77
  78         if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
  79                 dev_info(&client->dev,
  80                         "low voltage detected, date/time is not reliable.\n");
  81
  82         dev_dbg(&client->dev,
  83                 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
  84                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
  85                 __FUNCTION__,
  86                 buf[0], buf[1], buf[2], buf[3],
  87                 buf[4], buf[5], buf[6], buf[7],
  88                 buf[8]);
  89
  90
  91         tm->tm_sec = BCD2BIN(buf[PCF8563_REG_SC] & 0x7F);
  92         tm->tm_min = BCD2BIN(buf[PCF8563_REG_MN] & 0x7F);
  93         tm->tm_hour = BCD2BIN(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
  94         tm->tm_mday = BCD2BIN(buf[PCF8563_REG_DM] & 0x3F);
  95         tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
  96         tm->tm_mon = BCD2BIN(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
  97         tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR])
  98                 + (buf[PCF8563_REG_MO] & PCF8563_MO_C ? 0 : 100);
  99
 100         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 101                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 102                 __FUNCTION__,
 103                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 104                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 105
 106         /* the clock can give out invalid datetime, but we cannot return
 107          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
 108          */
 109         if (rtc_valid_tm(tm) < 0)
 110                 dev_err(&client->dev, "retrieved date/time is not valid.\n");
 111
 112         return 0;
 113 }
 114
 115 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 116 {
 117         int i, err;
 118         unsigned char buf[9];
 119
 120         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 121                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 122                 __FUNCTION__,
 123                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 124                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 125
 126         /* hours, minutes and seconds */
 127         buf[PCF8563_REG_SC] = BIN2BCD(tm->tm_sec);
 128         buf[PCF8563_REG_MN] = BIN2BCD(tm->tm_min);
 129         buf[PCF8563_REG_HR] = BIN2BCD(tm->tm_hour);
 130
 131         buf[PCF8563_REG_DM] = BIN2BCD(tm->tm_mday);
 132
 133         /* month, 1 - 12 */
 134         buf[PCF8563_REG_MO] = BIN2BCD(tm->tm_mon + 1);
 135
 136         /* year and century */
 137         buf[PCF8563_REG_YR] = BIN2BCD(tm->tm_year % 100);
 138         if (tm->tm_year < 100)
 139                 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
 140
 141         buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 142
 143         /* write register's data */
 144         for (i = 0; i < 7; i++) {
 145                 unsigned char data[2] = { PCF8563_REG_SC + i,
 146                                                 buf[PCF8563_REG_SC + i] };
 147
 148                 err = i2c_master_send(client, data, sizeof(data));
 149                 if (err != sizeof(data)) {
 150                         dev_err(&client->dev,
 151                                 "%s: err=%d addr=%02x, data=%02x\n",
 152                                 __FUNCTION__, err, data[0], data[1]);
 153                         return -EIO;
 154                 }
 155         };
 156
 157         return 0;
 158 }
 159
 160 struct pcf8563_limit
 161 {
 162         unsigned char reg;
 163         unsigned char mask;
 164         unsigned char min;
 165         unsigned char max;
 166 };
 167
 168 static int pcf8563_validate_client(struct i2c_client *client)
 169 {
 170         int i;
 171
 172         static const struct pcf8563_limit pattern[] = {
 173                 /* register, mask, min, max */
 174                 { PCF8563_REG_SC,       0x7F,   0,      59      },
 175                 { PCF8563_REG_MN,       0x7F,   0,      59      },
 176                 { PCF8563_REG_HR,       0x3F,   0,      23      },
 177                 { PCF8563_REG_DM,       0x3F,   0,      31      },
 178                 { PCF8563_REG_MO,       0x1F,   0,      12      },
 179         };
 180
 181         /* check limits (only registers with bcd values) */
 182         for (i = 0; i < ARRAY_SIZE(pattern); i++) {
 183                 int xfer;
 184                 unsigned char value;
 185                 unsigned char buf = pattern[i].reg;
 186
 187                 struct i2c_msg msgs[] = {
 188                         { client->addr, 0, 1, &buf },
 189                         { client->addr, I2C_M_RD, 1, &buf },
 190                 };
 191
 192                 xfer = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 193
 194                 if (xfer != ARRAY_SIZE(msgs)) {
 195                         dev_err(&client->dev,
 196                                 "%s: could not read register 0x%02X\n",
 197                                 __FUNCTION__, pattern[i].reg);
 198
 199                         return -EIO;
 200                 }
 201
 202                 value = BCD2BIN(buf & pattern[i].mask);
 203
 204                 if (value > pattern[i].max ||
 205                         value < pattern[i].min) {
 206                         dev_dbg(&client->dev,
 207                                 "%s: pattern=%d, reg=%x, mask=0x%02x, min=%d, "
 208                                 "max=%d, value=%d, raw=0x%02X\n",
 209                                 __FUNCTION__, i, pattern[i].reg, pattern[i].mask,
 210                                 pattern[i].min, pattern[i].max,
 211                                 value, buf);
 212
 213                         return -ENODEV;
 214                 }
 215         }
 216
 217         return 0;
 218 }
 219
 220 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 221 {
 222         return pcf8563_get_datetime(to_i2c_client(dev), tm);
 223 }
 224
 225 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 226 {
 227         return pcf8563_set_datetime(to_i2c_client(dev), tm);
 228 }
 229
 230 static const struct rtc_class_ops pcf8563_rtc_ops = {
 231         .read_time      = pcf8563_rtc_read_time,
 232         .set_time       = pcf8563_rtc_set_time,
 233 };
 234
 235 static int pcf8563_attach(struct i2c_adapter *adapter)
 236 {
 237         return i2c_probe(adapter, &addr_data, pcf8563_probe);
 238 }
 239
 240 static struct i2c_driver pcf8563_driver = {
 241         .driver         = {
 242                 .name   = "pcf8563",
 243         },
 244         .id             = I2C_DRIVERID_PCF8563,
 245         .attach_adapter = &pcf8563_attach,
 246         .detach_client  = &pcf8563_detach,
 247 };
 248
 249 static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind)
 250 {
 251         struct i2c_client *client;
 252         struct rtc_device *rtc;
 253
 254         int err = 0;
 255
 256         dev_dbg(adapter->class_dev.dev, "%s\n", __FUNCTION__);
 257
 258         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
 259                 err = -ENODEV;
 260                 goto exit;
 261         }
 262
 263         if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
 264                 err = -ENOMEM;
 265                 goto exit;
 266         }
 267
 268         client->addr = address;
 269         client->driver = &pcf8563_driver;
 270         client->adapter = adapter;
 271
 272         strlcpy(client->name, pcf8563_driver.driver.name, I2C_NAME_SIZE);
 273
 274         /* Verify the chip is really an PCF8563 */
 275         if (kind < 0) {
 276                 if (pcf8563_validate_client(client) < 0) {
 277                         err = -ENODEV;
 278                         goto exit_kfree;
 279                 }
 280         }
 281
 282         /* Inform the i2c layer */
 283         if ((err = i2c_attach_client(client)))
 284                 goto exit_kfree;
 285
 286         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 287
 288         rtc = rtc_device_register(pcf8563_driver.driver.name, &client->dev,
 289                                 &pcf8563_rtc_ops, THIS_MODULE);
 290
 291         if (IS_ERR(rtc)) {
 292                 err = PTR_ERR(rtc);
 293                 goto exit_detach;
 294         }
 295
 296         i2c_set_clientdata(client, rtc);
 297
 298         return 0;
 299
 300 exit_detach:
 301         i2c_detach_client(client);
 302
 303 exit_kfree:
 304         kfree(client);
 305
 306 exit:
 307         return err;
 308 }
 309
 310 static int pcf8563_detach(struct i2c_client *client)
 311 {
 312         int err;
 313         struct rtc_device *rtc = i2c_get_clientdata(client);
 314
 315         if (rtc)
 316                 rtc_device_unregister(rtc);
 317
 318         if ((err = i2c_detach_client(client)))
 319                 return err;
 320
 321         kfree(client);
 322
 323         return 0;
 324 }
 325
 326 static int __init pcf8563_init(void)
 327 {
 328         return i2c_add_driver(&pcf8563_driver);
 329 }
 330
 331 static void __exit pcf8563_exit(void)
 332 {
 333         i2c_del_driver(&pcf8563_driver);
 334 }
 335
 336 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 337 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
 338 MODULE_LICENSE("GPL");
 339 MODULE_VERSION(DRV_VERSION);
 340
 341 module_init(pcf8563_init);
 342 module_exit(pcf8563_exit);