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/acorn/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 = i2c_transfer(client->adapter, msg, 2);
 123
 124         dev_dbg(&client->adapter->dev,
 125                 "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
 126                 __FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
 127                 buf[4], buf[5], buf[6]);
 128
 129         if (result >= 0) {
 130                 dt->tm_sec = BCD2BIN(buf[0]);
 131                 dt->tm_min = BCD2BIN(buf[1]);
 132                 val = buf[2] & 0x3f;
 133                 dt->tm_hour = BCD2BIN(val);
 134                 dt->tm_wday = BCD2BIN(buf[3]) - 1;
 135                 dt->tm_mday = BCD2BIN(buf[4]);
 136                 val = buf[5] & 0x7f;
 137                 dt->tm_mon = BCD2BIN(val);
 138                 dt->tm_year = 1900 + BCD2BIN(buf[6]);
 139                 if (buf[5] & 0x80)
 140                         dt->tm_year += 100;
 141
 142                 dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, "
 143                         "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 144                         __FUNCTION__, dt->tm_sec, dt->tm_min,
 145                         dt->tm_hour, dt->tm_mday,
 146                         dt->tm_mon, dt->tm_year, dt->tm_wday);
 147         } else {
 148                 dev_err(&client->adapter->dev, "ds1337[%d]: error reading "
 149                         "data! %d\n", data->id, result);
 150                 result = -EIO;
 151         }
 152
 153         return result;
 154 }
 155
 156 static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt)
 157 {
 158         struct ds1337_data *data = i2c_get_clientdata(client);
 159         int result;
 160         u8 buf[8];
 161         u8 val;
 162         struct i2c_msg msg[1];
 163
 164         if (!dt) {
 165                 dev_dbg(&client->adapter->dev, "%s: EINVAL: dt=NULL\n",
 166                         __FUNCTION__);
 167
 168                 return -EINVAL;
 169         }
 170
 171         dev_dbg(&client->adapter->dev, "%s: secs=%d, mins=%d, hours=%d, "
 172                 "mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
 173                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 174                 dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);
 175
 176         buf[0] = 0;             /* reg offset */
 177         buf[1] = BIN2BCD(dt->tm_sec);
 178         buf[2] = BIN2BCD(dt->tm_min);
 179         buf[3] = BIN2BCD(dt->tm_hour) | (1 << 6);
 180         buf[4] = BIN2BCD(dt->tm_wday) + 1;
 181         buf[5] = BIN2BCD(dt->tm_mday);
 182         buf[6] = BIN2BCD(dt->tm_mon);
 183         if (dt->tm_year >= 2000) {
 184                 val = dt->tm_year - 2000;
 185                 buf[6] |= (1 << 7);
 186         } else {
 187                 val = dt->tm_year - 1900;
 188         }
 189         buf[7] = BIN2BCD(val);
 190
 191         msg[0].addr = client->addr;
 192         msg[0].flags = 0;
 193         msg[0].len = sizeof(buf);
 194         msg[0].buf = &buf[0];
 195
 196         result = i2c_transfer(client->adapter, msg, 1);
 197         if (result < 0) {
 198                 dev_err(&client->adapter->dev, "ds1337[%d]: error "
 199                         "writing data! %d\n", data->id, result);
 200                 result = -EIO;
 201         } else {
 202                 result = 0;
 203         }
 204
 205         return result;
 206 }
 207
 208 static int ds1337_command(struct i2c_client *client, unsigned int cmd,
 209                           void *arg)
 210 {
 211         dev_dbg(&client->adapter->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
 212
 213         switch (cmd) {
 214         case DS1337_GET_DATE:
 215                 return ds1337_get_datetime(client, arg);
 216
 217         case DS1337_SET_DATE:
 218                 return ds1337_set_datetime(client, arg);
 219
 220         default:
 221                 return -EINVAL;
 222         }
 223 }
 224
 225 /*
 226  * Public API for access to specific device. Useful for low-level
 227  * RTC access from kernel code.
 228  */
 229 int ds1337_do_command(int id, int cmd, void *arg)
 230 {
 231         struct list_head *walk;
 232         struct list_head *tmp;
 233         struct ds1337_data *data;
 234
 235         list_for_each_safe(walk, tmp, &ds1337_clients) {
 236                 data = list_entry(walk, struct ds1337_data, list);
 237                 if (data->id == id)
 238                         return ds1337_command(&data->client, cmd, arg);
 239         }
 240
 241         return -ENODEV;
 242 }
 243
 244 static int ds1337_attach_adapter(struct i2c_adapter *adapter)
 245 {
 246         return i2c_detect(adapter, &addr_data, ds1337_detect);
 247 }
 248
 249 /*
 250  * The following function does more than just detection. If detection
 251  * succeeds, it also registers the new chip.
 252  */
 253 static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
 254 {
 255         struct i2c_client *new_client;
 256         struct ds1337_data *data;
 257         int err = 0;
 258         const char *name = "";
 259
 260         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 261                                      I2C_FUNC_I2C))
 262                 goto exit;
 263
 264         if (!(data = kmalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
 265                 err = -ENOMEM;
 266                 goto exit;
 267         }
 268         memset(data, 0, sizeof(struct ds1337_data));
 269         INIT_LIST_HEAD(&data->list);
 270
 271         /* The common I2C client data is placed right before the
 272          * DS1337-specific data.
 273          */
 274         new_client = &data->client;
 275         i2c_set_clientdata(new_client, data);
 276         new_client->addr = address;
 277         new_client->adapter = adapter;
 278         new_client->driver = &ds1337_driver;
 279         new_client->flags = 0;
 280
 281         /*
 282          * Now we do the remaining detection. A negative kind means that
 283          * the driver was loaded with no force parameter (default), so we
 284          * must both detect and identify the chip. A zero kind means that
 285          * the driver was loaded with the force parameter, the detection
 286          * step shall be skipped. A positive kind means that the driver
 287          * was loaded with the force parameter and a given kind of chip is
 288          * requested, so both the detection and the identification steps
 289          * are skipped.
 290          *
 291          * For detection, we read registers that are most likely to cause
 292          * detection failure, i.e. those that have more bits with fixed
 293          * or reserved values.
 294          */
 295
 296         /* Default to an DS1337 if forced */
 297         if (kind == 0)
 298                 kind = ds1337;
 299
 300         if (kind < 0) {         /* detection and identification */
 301                 u8 data;
 302
 303                 /* Check that status register bits 6-2 are zero */
 304                 if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) ||
 305                     (data & 0x7c))
 306                         goto exit_free;
 307
 308                 /* Check for a valid day register value */
 309                 if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) ||
 310                     (data == 0) || (data & 0xf8))
 311                         goto exit_free;
 312
 313                 /* Check for a valid date register value */
 314                 if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) ||
 315                     (data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) ||
 316                     (data >= 0x32))
 317                         goto exit_free;
 318
 319                 /* Check for a valid month register value */
 320                 if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) ||
 321                     (data == 0) || (data & 0x60) || ((data & 0x0f) > 9) ||
 322                     ((data >= 0x13) && (data <= 0x19)))
 323                         goto exit_free;
 324
 325                 /* Check that control register bits 6-5 are zero */
 326                 if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) ||
 327                     (data & 0x60))
 328                         goto exit_free;
 329
 330                 kind = ds1337;
 331         }
 332
 333         if (kind == ds1337)
 334                 name = "ds1337";
 335
 336         /* We can fill in the remaining client fields */
 337         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 338
 339         /* Tell the I2C layer a new client has arrived */
 340         if ((err = i2c_attach_client(new_client)))
 341                 goto exit_free;
 342
 343         /* Initialize the DS1337 chip */
 344         ds1337_init_client(new_client);
 345
 346         /* Add client to local list */
 347         data->id = ds1337_id++;
 348         list_add(&data->list, &ds1337_clients);
 349
 350         return 0;
 351
 352 exit_free:
 353         kfree(data);
 354 exit:
 355         return err;
 356 }
 357
 358 static void ds1337_init_client(struct i2c_client *client)
 359 {
 360         s32 val;
 361
 362         /* Ensure that device is set in 24-hour mode */
 363         val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR);
 364         if ((val >= 0) && (val & (1 << 6)) == 0)
 365                 i2c_smbus_write_byte_data(client, DS1337_REG_HOUR,
 366                                           val | (1 << 6));
 367 }
 368
 369 static int ds1337_detach_client(struct i2c_client *client)
 370 {
 371         int err;
 372         struct ds1337_data *data = i2c_get_clientdata(client);
 373
 374         if ((err = i2c_detach_client(client))) {
 375                 dev_err(&client->dev, "Client deregistration failed, "
 376                         "client not detached.\n");
 377                 return err;
 378         }
 379
 380         list_del(&data->list);
 381         kfree(data);
 382         return 0;
 383 }
 384
 385 static int __init ds1337_init(void)
 386 {
 387         return i2c_add_driver(&ds1337_driver);
 388 }
 389
 390 static void __exit ds1337_exit(void)
 391 {
 392         i2c_del_driver(&ds1337_driver);
 393 }
 394
 395 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 396 MODULE_DESCRIPTION("DS1337 RTC driver");
 397 MODULE_LICENSE("GPL");
 398
 399 module_init(ds1337_init);
 400 module_exit(ds1337_exit);