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 and DS1339 real time clock chip
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/i2c.h>
  20 #include <linux/i2c-sensor.h>
  21 #include <linux/string.h>
  22 #include <linux/rtc.h>          /* get the user-level API */
  23 #include <linux/bcd.h>
  24 #include <linux/list.h>
  25
  26 /* Device registers */
  27 #define DS1337_REG_HOUR         2
  28 #define DS1337_REG_DAY          3
  29 #define DS1337_REG_DATE         4
  30 #define DS1337_REG_MONTH        5
  31 #define DS1337_REG_CONTROL      14
  32 #define DS1337_REG_STATUS       15
  33
  34 /* FIXME - how do we export these interface constants? */
  35 #define DS1337_GET_DATE         0
  36 #define DS1337_SET_DATE         1
  37
  38 /*
  39  * Functions declaration
  40  */
  41 static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
  42 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
  43
  44 SENSORS_INSMOD_1(ds1337);
  45
  46 static int ds1337_attach_adapter(struct i2c_adapter *adapter);
  47 static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind);
  48 static void ds1337_init_client(struct i2c_client *client);
  49 static int ds1337_detach_client(struct i2c_client *client);
  50 static int ds1337_command(struct i2c_client *client, unsigned int cmd,
  51                           void *arg);
  52
  53 /*
  54  * Driver data (common to all clients)
  55  */
  56 static struct i2c_driver ds1337_driver = {
  57         .owner          = THIS_MODULE,
  58         .name           = "ds1337",
  59         .flags          = I2C_DF_NOTIFY,
  60         .attach_adapter = ds1337_attach_adapter,
  61         .detach_client  = ds1337_detach_client,
  62         .command        = ds1337_command,
  63 };
  64
  65 /*
  66  * Client data (each client gets its own)
  67  */
  68 struct ds1337_data {
  69         struct i2c_client client;
  70         struct list_head list;
  71 };
  72
  73 /*
  74  * Internal variables
  75  */
  76 static LIST_HEAD(ds1337_clients);
  77
  78 static inline int ds1337_read(struct i2c_client *client, u8 reg, u8 *value)
  79 {
  80         s32 tmp = i2c_smbus_read_byte_data(client, reg);
  81
  82         if (tmp < 0)
  83                 return -EIO;
  84
  85         *value = tmp;
  86
  87         return 0;
  88 }
  89
  90 /*
  91  * Chip access functions
  92  */
  93 static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *dt)
  94 {
  95         int result;
  96         u8 buf[7];
  97         u8 val;
  98         struct i2c_msg msg[2];
  99         u8 offs = 0;
 100
 101         if (!dt) {
 102                 dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
 103                 return -EINVAL;
 104         }
 105
 106         msg[0].addr = client->addr;
 107         msg[0].flags = 0;
 108         msg[0].len = 1;
 109         msg[0].buf = &offs;
 110
 111         msg[1].addr = client->addr;
 112         msg[1].flags = I2C_M_RD;
 113         msg[1].len = sizeof(buf);
 114         msg[1].buf = &buf[0];
 115
 116         result = i2c_transfer(client->adapter, msg, 2);
 117
 118         dev_dbg(&client->dev, "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
 119                 __FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
 120                 buf[4], buf[5], buf[6]);
 121
 122         if (result == 2) {
 123                 dt->tm_sec = BCD2BIN(buf[0]);
 124                 dt->tm_min = BCD2BIN(buf[1]);
 125                 val = buf[2] & 0x3f;
 126                 dt->tm_hour = BCD2BIN(val);
 127                 dt->tm_wday = BCD2BIN(buf[3]) - 1;
 128                 dt->tm_mday = BCD2BIN(buf[4]);
 129                 val = buf[5] & 0x7f;
 130                 dt->tm_mon = BCD2BIN(val) - 1;
 131                 dt->tm_year = BCD2BIN(buf[6]);
 132                 if (buf[5] & 0x80)
 133                         dt->tm_year += 100;
 134
 135                 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, "
 136                         "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 137                         __FUNCTION__, dt->tm_sec, dt->tm_min,
 138                         dt->tm_hour, dt->tm_mday,
 139                         dt->tm_mon, dt->tm_year, dt->tm_wday);
 140
 141                 return 0;
 142         }
 143
 144         dev_err(&client->dev, "error reading data! %d\n", result);
 145         return -EIO;
 146 }
 147
 148 static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt)
 149 {
 150         int result;
 151         u8 buf[8];
 152         u8 val;
 153         struct i2c_msg msg[1];
 154
 155         if (!dt) {
 156                 dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
 157                 return -EINVAL;
 158         }
 159
 160         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 161                 "mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
 162                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 163                 dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);
 164
 165         buf[0] = 0;             /* reg offset */
 166         buf[1] = BIN2BCD(dt->tm_sec);
 167         buf[2] = BIN2BCD(dt->tm_min);
 168         buf[3] = BIN2BCD(dt->tm_hour) | (1 << 6);
 169         buf[4] = BIN2BCD(dt->tm_wday) + 1;
 170         buf[5] = BIN2BCD(dt->tm_mday);
 171         buf[6] = BIN2BCD(dt->tm_mon) + 1;
 172         val = dt->tm_year;
 173         if (val >= 100) {
 174                 val -= 100;
 175                 buf[6] |= (1 << 7);
 176         }
 177         buf[7] = BIN2BCD(val);
 178
 179         msg[0].addr = client->addr;
 180         msg[0].flags = 0;
 181         msg[0].len = sizeof(buf);
 182         msg[0].buf = &buf[0];
 183
 184         result = i2c_transfer(client->adapter, msg, 1);
 185         if (result == 1)
 186                 return 0;
 187
 188         dev_err(&client->dev, "error writing data! %d\n", result);
 189         return -EIO;
 190 }
 191
 192 static int ds1337_command(struct i2c_client *client, unsigned int cmd,
 193                           void *arg)
 194 {
 195         dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
 196
 197         switch (cmd) {
 198         case DS1337_GET_DATE:
 199                 return ds1337_get_datetime(client, arg);
 200
 201         case DS1337_SET_DATE:
 202                 return ds1337_set_datetime(client, arg);
 203
 204         default:
 205                 return -EINVAL;
 206         }
 207 }
 208
 209 /*
 210  * Public API for access to specific device. Useful for low-level
 211  * RTC access from kernel code.
 212  */
 213 int ds1337_do_command(int bus, int cmd, void *arg)
 214 {
 215         struct list_head *walk;
 216         struct list_head *tmp;
 217         struct ds1337_data *data;
 218
 219         list_for_each_safe(walk, tmp, &ds1337_clients) {
 220                 data = list_entry(walk, struct ds1337_data, list);
 221                 if (data->client.adapter->nr == bus)
 222                         return ds1337_command(&data->client, cmd, arg);
 223         }
 224
 225         return -ENODEV;
 226 }
 227
 228 static int ds1337_attach_adapter(struct i2c_adapter *adapter)
 229 {
 230         return i2c_detect(adapter, &addr_data, ds1337_detect);
 231 }
 232
 233 /*
 234  * The following function does more than just detection. If detection
 235  * succeeds, it also registers the new chip.
 236  */
 237 static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
 238 {
 239         struct i2c_client *new_client;
 240         struct ds1337_data *data;
 241         int err = 0;
 242         const char *name = "";
 243
 244         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 245                                      I2C_FUNC_I2C))
 246                 goto exit;
 247
 248         if (!(data = kmalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
 249                 err = -ENOMEM;
 250                 goto exit;
 251         }
 252         memset(data, 0, sizeof(struct ds1337_data));
 253         INIT_LIST_HEAD(&data->list);
 254
 255         /* The common I2C client data is placed right before the
 256          * DS1337-specific data.
 257          */
 258         new_client = &data->client;
 259         i2c_set_clientdata(new_client, data);
 260         new_client->addr = address;
 261         new_client->adapter = adapter;
 262         new_client->driver = &ds1337_driver;
 263         new_client->flags = 0;
 264
 265         /*
 266          * Now we do the remaining detection. A negative kind means that
 267          * the driver was loaded with no force parameter (default), so we
 268          * must both detect and identify the chip. A zero kind means that
 269          * the driver was loaded with the force parameter, the detection
 270          * step shall be skipped. A positive kind means that the driver
 271          * was loaded with the force parameter and a given kind of chip is
 272          * requested, so both the detection and the identification steps
 273          * are skipped.
 274          *
 275          * For detection, we read registers that are most likely to cause
 276          * detection failure, i.e. those that have more bits with fixed
 277          * or reserved values.
 278          */
 279
 280         /* Default to an DS1337 if forced */
 281         if (kind == 0)
 282                 kind = ds1337;
 283
 284         if (kind < 0) {         /* detection and identification */
 285                 u8 data;
 286
 287                 /* Check that status register bits 6-2 are zero */
 288                 if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) ||
 289                     (data & 0x7c))
 290                         goto exit_free;
 291
 292                 /* Check for a valid day register value */
 293                 if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) ||
 294                     (data == 0) || (data & 0xf8))
 295                         goto exit_free;
 296
 297                 /* Check for a valid date register value */
 298                 if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) ||
 299                     (data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) ||
 300                     (data >= 0x32))
 301                         goto exit_free;
 302
 303                 /* Check for a valid month register value */
 304                 if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) ||
 305                     (data == 0) || (data & 0x60) || ((data & 0x0f) > 9) ||
 306                     ((data >= 0x13) && (data <= 0x19)))
 307                         goto exit_free;
 308
 309                 /* Check that control register bits 6-5 are zero */
 310                 if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) ||
 311                     (data & 0x60))
 312                         goto exit_free;
 313
 314                 kind = ds1337;
 315         }
 316
 317         if (kind == ds1337)
 318                 name = "ds1337";
 319
 320         /* We can fill in the remaining client fields */
 321         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 322
 323         /* Tell the I2C layer a new client has arrived */
 324         if ((err = i2c_attach_client(new_client)))
 325                 goto exit_free;
 326
 327         /* Initialize the DS1337 chip */
 328         ds1337_init_client(new_client);
 329
 330         /* Add client to local list */
 331         list_add(&data->list, &ds1337_clients);
 332
 333         return 0;
 334
 335 exit_free:
 336         kfree(data);
 337 exit:
 338         return err;
 339 }
 340
 341 static void ds1337_init_client(struct i2c_client *client)
 342 {
 343         s32 val;
 344
 345         /* Ensure that device is set in 24-hour mode */
 346         val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR);
 347         if ((val >= 0) && (val & (1 << 6)) == 0)
 348                 i2c_smbus_write_byte_data(client, DS1337_REG_HOUR,
 349                                           val | (1 << 6));
 350 }
 351
 352 static int ds1337_detach_client(struct i2c_client *client)
 353 {
 354         int err;
 355         struct ds1337_data *data = i2c_get_clientdata(client);
 356
 357         if ((err = i2c_detach_client(client))) {
 358                 dev_err(&client->dev, "Client deregistration failed, "
 359                         "client not detached.\n");
 360                 return err;
 361         }
 362
 363         list_del(&data->list);
 364         kfree(data);
 365         return 0;
 366 }
 367
 368 static int __init ds1337_init(void)
 369 {
 370         return i2c_add_driver(&ds1337_driver);
 371 }
 372
 373 static void __exit ds1337_exit(void)
 374 {
 375         i2c_del_driver(&ds1337_driver);
 376 }
 377
 378 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 379 MODULE_DESCRIPTION("DS1337 RTC driver");
 380 MODULE_LICENSE("GPL");
 381
 382 EXPORT_SYMBOL_GPL(ds1337_do_command);
 383
 384 module_init(ds1337_init);
 385 module_exit(ds1337_exit);