drivers/i2c/chips/ds1337.c

   1 /*
   2  *  linux/drivers/i2c/chips/ds1337.c
   3  *
   4  *  Copyright (C) 2005 James Chapman <jchapman@katalix.com>
   5  *
   6  *      based on linux/drivers/acron/char/pcf8583.c
   7  *  Copyright (C) 2000 Russell King
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * Driver for Dallas Semiconductor DS1337 real time clock chip
  14  */
  15
  16 #include <linux/config.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/i2c.h>
  21 #include <linux/i2c-sensor.h>
  22 #include <linux/string.h>
  23 #include <linux/rtc.h>          /* get the user-level API */
  24 #include <linux/bcd.h>
  25 #include <linux/list.h>
  26
  27 /* Device registers */
  28 #define DS1337_REG_HOUR         2
  29 #define DS1337_REG_DAY          3
  30 #define DS1337_REG_DATE         4
  31 #define DS1337_REG_MONTH        5
  32 #define DS1337_REG_CONTROL      14
  33 #define DS1337_REG_STATUS       15
  34
  35 /* FIXME - how do we export these interface constants? */
  36 #define DS1337_GET_DATE         0
  37 #define DS1337_SET_DATE         1
  38
  39 /*
  40  * Functions declaration
  41  */
  42 static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
  43 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
  44
  45 SENSORS_INSMOD_1(ds1337);
  46
  47 static int ds1337_attach_adapter(struct i2c_adapter *adapter);
  48 static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind);
  49 static void ds1337_init_client(struct i2c_client *client);
  50 static int ds1337_detach_client(struct i2c_client *client);
  51 static int ds1337_command(struct i2c_client *client, unsigned int cmd,
  52                           void *arg);
  53
  54 /*
  55  * Driver data (common to all clients)
  56  */
  57 static struct i2c_driver ds1337_driver = {
  58         .owner          = THIS_MODULE,
  59         .name           = "ds1337",
  60         .flags          = I2C_DF_NOTIFY,
  61         .attach_adapter = ds1337_attach_adapter,
  62         .detach_client  = ds1337_detach_client,
  63         .command        = ds1337_command,
  64 };
  65
  66 /*
  67  * Client data (each client gets its own)
  68  */
  69 struct ds1337_data {
  70         struct i2c_client client;
  71         struct list_head list;
  72         int id;
  73 };
  74
  75 /*
  76  * Internal variables
  77  */
  78 static int ds1337_id;
  79 static LIST_HEAD(ds1337_clients);
  80
  81 static inline int ds1337_read(struct i2c_client *client, u8 reg, u8 *value)
  82 {
  83         s32 tmp = i2c_smbus_read_byte_data(client, reg);
  84
  85         if (tmp < 0)
  86                 return -EIO;
  87
  88         *value = tmp;
  89
  90         return 0;
  91 }
  92
  93 /*
  94  * Chip access functions
  95  */
  96 static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *dt)
  97 {
  98         struct ds1337_data *data = i2c_get_clientdata(client);
  99         int result;
 100         u8 buf[7];
 101         u8 val;
 102         struct i2c_msg msg[2];
 103         u8 offs = 0;
 104
 105         if (!dt) {
 106                 dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n",
 107                         __FUNCTION__);
 108
 109                 return -EINVAL;
 110         }
 111
 112         msg[0].addr = client->addr;
 113         msg[0].flags = 0;
 114         msg[0].len = 1;
 115         msg[0].buf = &offs;
 116
 117         msg[1].addr = client->addr;
 118         msg[1].flags = I2C_M_RD;
 119         msg[1].len = sizeof(buf);
 120         msg[1].buf = &buf[0];
 121
 122         result = client->adapter->algo->master_xfer(client->adapter,
 123                                                     &msg[0], 2);
 124
 125         dev_dbg(&client->adapter->dev,
 126                 "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
 127                 __FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
 128                 buf[4], buf[5], buf[6]);
 129
 130         if (result >= 0) {
 131                 dt->tm_sec = BCD_TO_BIN(buf[0]);
 132                 dt->tm_min = BCD_TO_BIN(buf[1]);
 133                 val = buf[2] & 0x3f;
 134                 dt->tm_hour = BCD_TO_BIN(val);
 135                 dt->tm_wday = BCD_TO_BIN(buf[3]) - 1;
 136                 dt->tm_mday = BCD_TO_BIN(buf[4]);
 137                 val = buf[5] & 0x7f;
 138                 dt->tm_mon = BCD_TO_BIN(val);
 139                 dt->tm_year = 1900 + BCD_TO_BIN(buf[6]);
 140                 if (buf[5] & 0x80)
 141                         dt->tm_year += 100;
 142
 143                 dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, "
 144                         "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 145                         __FUNCTION__, dt->tm_sec, dt->tm_min,
 146                         dt->tm_hour, dt->tm_mday,
 147                         dt->tm_mon, dt->tm_year, dt->tm_wday);
 148         } else {
 149                 dev_err(&client->adapter->dev, "ds1337[%d]: error reading "
 150                         "data! %d\n", data->id, result);
 151                 result = -EIO;
 152         }
 153
 154         return result;
 155 }
 156
 157 static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt)
 158 {
 159         struct ds1337_data *data = i2c_get_clientdata(client);
 160         int result;
 161         u8 buf[8];
 162         u8 val;
 163         struct i2c_msg msg[1];
 164
 165         if (!dt) {
 166                 dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n",
 167                         __FUNCTION__);
 168
 169                 return -EINVAL;
 170         }
 171
 172         dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, hours=%d, "
 173                 "mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
 174                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 175                 dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);
 176
 177         buf[0] = 0;             /* reg offset */
 178         buf[1] = BIN_TO_BCD(dt->tm_sec);
 179         buf[2] = BIN_TO_BCD(dt->tm_min);
 180         buf[3] = BIN_TO_BCD(dt->tm_hour) | (1 << 6);
 181         buf[4] = BIN_TO_BCD(dt->tm_wday) + 1;
 182         buf[5] = BIN_TO_BCD(dt->tm_mday);
 183         buf[6] = BIN_TO_BCD(dt->tm_mon);
 184         if (dt->tm_year >= 2000) {
 185                 val = dt->tm_year - 2000;
 186                 buf[6] |= (1 << 7);
 187         } else {
 188                 val = dt->tm_year - 1900;
 189         }
 190         buf[7] = BIN_TO_BCD(val);
 191
 192         msg[0].addr = client->addr;
 193         msg[0].flags = 0;
 194         msg[0].len = sizeof(buf);
 195         msg[0].buf = &buf[0];
 196
 197         result = client->adapter->algo->master_xfer(client->adapter,
 198                                                     &msg[0], 1);
 199         if (result < 0) {
 200                 dev_err(&client->adapter->dev, "ds1337[%d]: error "
 201                         "writing data! %d\n", data->id, result);
 202                 result = -EIO;
 203         } else {
 204                 result = 0;
 205         }
 206
 207         return result;
 208 }
 209
 210 static int ds1337_command(struct i2c_client *client, unsigned int cmd,
 211                           void *arg)
 212 {
 213         dev_dbg(&client->adapter->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
 214
 215         switch (cmd) {
 216         case DS1337_GET_DATE:
 217                 return ds1337_get_datetime(client, arg);
 218
 219         case DS1337_SET_DATE:
 220                 return ds1337_set_datetime(client, arg);
 221
 222         default:
 223                 return -EINVAL;
 224         }
 225 }
 226
 227 /*
 228  * Public API for access to specific device. Useful for low-level
 229  * RTC access from kernel code.
 230  */
 231 int ds1337_do_command(int id, int cmd, void *arg)
 232 {
 233         struct list_head *walk;
 234         struct list_head *tmp;
 235         struct ds1337_data *data;
 236
 237         list_for_each_safe(walk, tmp, &ds1337_clients) {
 238                 data = list_entry(walk, struct ds1337_data, list);
 239                 if (data->id == id)
 240                         return ds1337_command(&data->client, cmd, arg);
 241         }
 242
 243         return -ENODEV;
 244 }
 245
 246 static int ds1337_attach_adapter(struct i2c_adapter *adapter)
 247 {
 248         return i2c_detect(adapter, &addr_data, ds1337_detect);
 249 }
 250
 251 /*
 252  * The following function does more than just detection. If detection
 253  * succeeds, it also registers the new chip.
 254  */
 255 static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
 256 {
 257         struct i2c_client *new_client;
 258         struct ds1337_data *data;
 259         int err = 0;
 260         const char *name = "";
 261
 262         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 263                                      I2C_FUNC_I2C))
 264                 goto exit;
 265
 266         if (!(data = kmalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
 267                 err = -ENOMEM;
 268                 goto exit;
 269         }
 270         memset(data, 0, sizeof(struct ds1337_data));
 271         INIT_LIST_HEAD(&data->list);
 272
 273         /* The common I2C client data is placed right before the
 274          * DS1337-specific data.
 275          */
 276         new_client = &data->client;
 277         i2c_set_clientdata(new_client, data);
 278         new_client->addr = address;
 279         new_client->adapter = adapter;
 280         new_client->driver = &ds1337_driver;
 281         new_client->flags = 0;
 282
 283         /*
 284          * Now we do the remaining detection. A negative kind means that
 285          * the driver was loaded with no force parameter (default), so we
 286          * must both detect and identify the chip. A zero kind means that
 287          * the driver was loaded with the force parameter, the detection
 288          * step shall be skipped. A positive kind means that the driver
 289          * was loaded with the force parameter and a given kind of chip is
 290          * requested, so both the detection and the identification steps
 291          * are skipped.
 292          *
 293          * For detection, we read registers that are most likely to cause
 294          * detection failure, i.e. those that have more bits with fixed
 295          * or reserved values.
 296          */
 297
 298         /* Default to an DS1337 if forced */
 299         if (kind == 0)
 300                 kind = ds1337;
 301
 302         if (kind < 0) {         /* detection and identification */
 303                 u8 data;
 304
 305                 /* Check that status register bits 6-2 are zero */
 306                 if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) ||
 307                     (data & 0x7c))
 308                         goto exit_free;
 309
 310                 /* Check for a valid day register value */
 311                 if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) ||
 312                     (data == 0) || (data & 0xf8))
 313                         goto exit_free;
 314
 315                 /* Check for a valid date register value */
 316                 if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) ||
 317                     (data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) ||
 318                     (data >= 0x32))
 319                         goto exit_free;
 320
 321                 /* Check for a valid month register value */
 322                 if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) ||
 323                     (data == 0) || (data & 0x60) || ((data & 0x0f) > 9) ||
 324                     ((data >= 0x13) && (data <= 0x19)))
 325                         goto exit_free;
 326
 327                 /* Check that control register bits 6-5 are zero */
 328                 if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) ||
 329                     (data & 0x60))
 330                         goto exit_free;
 331
 332                 kind = ds1337;
 333         }
 334
 335         if (kind == ds1337)
 336                 name = "ds1337";
 337
 338         /* We can fill in the remaining client fields */
 339         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 340
 341         /* Tell the I2C layer a new client has arrived */
 342         if ((err = i2c_attach_client(new_client)))
 343                 goto exit_free;
 344
 345         /* Initialize the DS1337 chip */
 346         ds1337_init_client(new_client);
 347
 348         /* Add client to local list */
 349         data->id = ds1337_id++;
 350         list_add(&data->list, &ds1337_clients);
 351
 352         return 0;
 353
 354 exit_free:
 355         kfree(data);
 356 exit:
 357         return err;
 358 }
 359
 360 static void ds1337_init_client(struct i2c_client *client)
 361 {
 362         s32 val;
 363
 364         /* Ensure that device is set in 24-hour mode */
 365         val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR);
 366         if ((val >= 0) && (val & (1 << 6)) == 0)
 367                 i2c_smbus_write_byte_data(client, DS1337_REG_HOUR,
 368                                           val | (1 << 6));
 369 }
 370
 371 static int ds1337_detach_client(struct i2c_client *client)
 372 {
 373         int err;
 374         struct ds1337_data *data = i2c_get_clientdata(client);
 375
 376         if ((err = i2c_detach_client(client))) {
 377                 dev_err(&client->dev, "Client deregistration failed, "
 378                         "client not detached.\n");
 379                 return err;
 380         }
 381
 382         list_del(&data->list);
 383         kfree(data);
 384         return 0;
 385 }
 386
 387 static int __init ds1337_init(void)
 388 {
 389         return i2c_add_driver(&ds1337_driver);
 390 }
 391
 392 static void __exit ds1337_exit(void)
 393 {
 394         i2c_del_driver(&ds1337_driver);
 395 }
 396
 397 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 398 MODULE_DESCRIPTION("DS1337 RTC driver");
 399 MODULE_LICENSE("GPL");
 400
 401 module_init(ds1337_init);
 402 module_exit(ds1337_exit);