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/string.h>
  21 #include <linux/rtc.h>          /* get the user-level API */
  22 #include <linux/bcd.h>
  23 #include <linux/list.h>
  24
  25 /* Device registers */
  26 #define DS1337_REG_HOUR         2
  27 #define DS1337_REG_DAY          3
  28 #define DS1337_REG_DATE         4
  29 #define DS1337_REG_MONTH        5
  30 #define DS1337_REG_CONTROL      14
  31 #define DS1337_REG_STATUS       15
  32
  33 /* FIXME - how do we export these interface constants? */
  34 #define DS1337_GET_DATE         0
  35 #define DS1337_SET_DATE         1
  36
  37 /*
  38  * Functions declaration
  39  */
  40 static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
  41
  42 I2C_CLIENT_INSMOD_1(ds1337);
  43
  44 static int ds1337_attach_adapter(struct i2c_adapter *adapter);
  45 static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind);
  46 static void ds1337_init_client(struct i2c_client *client);
  47 static int ds1337_detach_client(struct i2c_client *client);
  48 static int ds1337_command(struct i2c_client *client, unsigned int cmd,
  49                           void *arg);
  50
  51 /*
  52  * Driver data (common to all clients)
  53  */
  54 static struct i2c_driver ds1337_driver = {
  55         .owner          = THIS_MODULE,
  56         .name           = "ds1337",
  57         .attach_adapter = ds1337_attach_adapter,
  58         .detach_client  = ds1337_detach_client,
  59         .command        = ds1337_command,
  60 };
  61
  62 /*
  63  * Client data (each client gets its own)
  64  */
  65 struct ds1337_data {
  66         struct i2c_client client;
  67         struct list_head list;
  68 };
  69
  70 /*
  71  * Internal variables
  72  */
  73 static LIST_HEAD(ds1337_clients);
  74
  75 static inline int ds1337_read(struct i2c_client *client, u8 reg, u8 *value)
  76 {
  77         s32 tmp = i2c_smbus_read_byte_data(client, reg);
  78
  79         if (tmp < 0)
  80                 return -EIO;
  81
  82         *value = tmp;
  83
  84         return 0;
  85 }
  86
  87 /*
  88  * Chip access functions
  89  */
  90 static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *dt)
  91 {
  92         int result;
  93         u8 buf[7];
  94         u8 val;
  95         struct i2c_msg msg[2];
  96         u8 offs = 0;
  97
  98         if (!dt) {
  99                 dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
 100                 return -EINVAL;
 101         }
 102
 103         msg[0].addr = client->addr;
 104         msg[0].flags = 0;
 105         msg[0].len = 1;
 106         msg[0].buf = &offs;
 107
 108         msg[1].addr = client->addr;
 109         msg[1].flags = I2C_M_RD;
 110         msg[1].len = sizeof(buf);
 111         msg[1].buf = &buf[0];
 112
 113         result = i2c_transfer(client->adapter, msg, 2);
 114
 115         dev_dbg(&client->dev, "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
 116                 __FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
 117                 buf[4], buf[5], buf[6]);
 118
 119         if (result == 2) {
 120                 dt->tm_sec = BCD2BIN(buf[0]);
 121                 dt->tm_min = BCD2BIN(buf[1]);
 122                 val = buf[2] & 0x3f;
 123                 dt->tm_hour = BCD2BIN(val);
 124                 dt->tm_wday = BCD2BIN(buf[3]) - 1;
 125                 dt->tm_mday = BCD2BIN(buf[4]);
 126                 val = buf[5] & 0x7f;
 127                 dt->tm_mon = BCD2BIN(val) - 1;
 128                 dt->tm_year = BCD2BIN(buf[6]);
 129                 if (buf[5] & 0x80)
 130                         dt->tm_year += 100;
 131
 132                 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, "
 133                         "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 134                         __FUNCTION__, dt->tm_sec, dt->tm_min,
 135                         dt->tm_hour, dt->tm_mday,
 136                         dt->tm_mon, dt->tm_year, dt->tm_wday);
 137
 138                 return 0;
 139         }
 140
 141         dev_err(&client->dev, "error reading data! %d\n", result);
 142         return -EIO;
 143 }
 144
 145 static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt)
 146 {
 147         int result;
 148         u8 buf[8];
 149         u8 val;
 150         struct i2c_msg msg[1];
 151
 152         if (!dt) {
 153                 dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
 154                 return -EINVAL;
 155         }
 156
 157         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 158                 "mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
 159                 dt->tm_sec, dt->tm_min, dt->tm_hour,
 160                 dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);
 161
 162         buf[0] = 0;             /* reg offset */
 163         buf[1] = BIN2BCD(dt->tm_sec);
 164         buf[2] = BIN2BCD(dt->tm_min);
 165         buf[3] = BIN2BCD(dt->tm_hour);
 166         buf[4] = BIN2BCD(dt->tm_wday + 1);
 167         buf[5] = BIN2BCD(dt->tm_mday);
 168         buf[6] = BIN2BCD(dt->tm_mon + 1);
 169         val = dt->tm_year;
 170         if (val >= 100) {
 171                 val -= 100;
 172                 buf[6] |= (1 << 7);
 173         }
 174         buf[7] = BIN2BCD(val);
 175
 176         msg[0].addr = client->addr;
 177         msg[0].flags = 0;
 178         msg[0].len = sizeof(buf);
 179         msg[0].buf = &buf[0];
 180
 181         result = i2c_transfer(client->adapter, msg, 1);
 182         if (result == 1)
 183                 return 0;
 184
 185         dev_err(&client->dev, "error writing data! %d\n", result);
 186         return -EIO;
 187 }
 188
 189 static int ds1337_command(struct i2c_client *client, unsigned int cmd,
 190                           void *arg)
 191 {
 192         dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
 193
 194         switch (cmd) {
 195         case DS1337_GET_DATE:
 196                 return ds1337_get_datetime(client, arg);
 197
 198         case DS1337_SET_DATE:
 199                 return ds1337_set_datetime(client, arg);
 200
 201         default:
 202                 return -EINVAL;
 203         }
 204 }
 205
 206 /*
 207  * Public API for access to specific device. Useful for low-level
 208  * RTC access from kernel code.
 209  */
 210 int ds1337_do_command(int bus, int cmd, void *arg)
 211 {
 212         struct list_head *walk;
 213         struct list_head *tmp;
 214         struct ds1337_data *data;
 215
 216         list_for_each_safe(walk, tmp, &ds1337_clients) {
 217                 data = list_entry(walk, struct ds1337_data, list);
 218                 if (data->client.adapter->nr == bus)
 219                         return ds1337_command(&data->client, cmd, arg);
 220         }
 221
 222         return -ENODEV;
 223 }
 224
 225 static int ds1337_attach_adapter(struct i2c_adapter *adapter)
 226 {
 227         return i2c_probe(adapter, &addr_data, ds1337_detect);
 228 }
 229
 230 /*
 231  * The following function does more than just detection. If detection
 232  * succeeds, it also registers the new chip.
 233  */
 234 static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
 235 {
 236         struct i2c_client *new_client;
 237         struct ds1337_data *data;
 238         int err = 0;
 239         const char *name = "";
 240
 241         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 242                                      I2C_FUNC_I2C))
 243                 goto exit;
 244
 245         if (!(data = kzalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
 246                 err = -ENOMEM;
 247                 goto exit;
 248         }
 249         INIT_LIST_HEAD(&data->list);
 250
 251         /* The common I2C client data is placed right before the
 252          * DS1337-specific data.
 253          */
 254         new_client = &data->client;
 255         i2c_set_clientdata(new_client, data);
 256         new_client->addr = address;
 257         new_client->adapter = adapter;
 258         new_client->driver = &ds1337_driver;
 259         new_client->flags = 0;
 260
 261         /*
 262          * Now we do the remaining detection. A negative kind means that
 263          * the driver was loaded with no force parameter (default), so we
 264          * must both detect and identify the chip. A zero kind means that
 265          * the driver was loaded with the force parameter, the detection
 266          * step shall be skipped. A positive kind means that the driver
 267          * was loaded with the force parameter and a given kind of chip is
 268          * requested, so both the detection and the identification steps
 269          * are skipped.
 270          *
 271          * For detection, we read registers that are most likely to cause
 272          * detection failure, i.e. those that have more bits with fixed
 273          * or reserved values.
 274          */
 275
 276         /* Default to an DS1337 if forced */
 277         if (kind == 0)
 278                 kind = ds1337;
 279
 280         if (kind < 0) {         /* detection and identification */
 281                 u8 data;
 282
 283                 /* Check that status register bits 6-2 are zero */
 284                 if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) ||
 285                     (data & 0x7c))
 286                         goto exit_free;
 287
 288                 /* Check for a valid day register value */
 289                 if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) ||
 290                     (data == 0) || (data & 0xf8))
 291                         goto exit_free;
 292
 293                 /* Check for a valid date register value */
 294                 if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) ||
 295                     (data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) ||
 296                     (data >= 0x32))
 297                         goto exit_free;
 298
 299                 /* Check for a valid month register value */
 300                 if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) ||
 301                     (data == 0) || (data & 0x60) || ((data & 0x0f) > 9) ||
 302                     ((data >= 0x13) && (data <= 0x19)))
 303                         goto exit_free;
 304
 305                 /* Check that control register bits 6-5 are zero */
 306                 if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) ||
 307                     (data & 0x60))
 308                         goto exit_free;
 309
 310                 kind = ds1337;
 311         }
 312
 313         if (kind == ds1337)
 314                 name = "ds1337";
 315
 316         /* We can fill in the remaining client fields */
 317         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 318
 319         /* Tell the I2C layer a new client has arrived */
 320         if ((err = i2c_attach_client(new_client)))
 321                 goto exit_free;
 322
 323         /* Initialize the DS1337 chip */
 324         ds1337_init_client(new_client);
 325
 326         /* Add client to local list */
 327         list_add(&data->list, &ds1337_clients);
 328
 329         return 0;
 330
 331 exit_free:
 332         kfree(data);
 333 exit:
 334         return err;
 335 }
 336
 337 static void ds1337_init_client(struct i2c_client *client)
 338 {
 339         u8 status, control;
 340
 341         /* On some boards, the RTC isn't configured by boot firmware.
 342          * Handle that case by starting/configuring the RTC now.
 343          */
 344         status = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 345         control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 346
 347         if ((status & 0x80) || (control & 0x80)) {
 348                 /* RTC not running */
 349                 u8 buf[16];
 350                 struct i2c_msg msg[1];
 351
 352                 dev_dbg(&client->dev, "%s: RTC not running!\n", __FUNCTION__);
 353
 354                 /* Initialize all, including STATUS and CONTROL to zero */
 355                 memset(buf, 0, sizeof(buf));
 356                 msg[0].addr = client->addr;
 357                 msg[0].flags = 0;
 358                 msg[0].len = sizeof(buf);
 359                 msg[0].buf = &buf[0];
 360
 361                 i2c_transfer(client->adapter, msg, 1);
 362         } else {
 363                 /* Running: ensure that device is set in 24-hour mode */
 364                 s32 val;
 365
 366                 val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR);
 367                 if ((val >= 0) && (val & (1 << 6)))
 368                         i2c_smbus_write_byte_data(client, DS1337_REG_HOUR,
 369                                                   val & 0x3f);
 370         }
 371 }
 372
 373 static int ds1337_detach_client(struct i2c_client *client)
 374 {
 375         int err;
 376         struct ds1337_data *data = i2c_get_clientdata(client);
 377
 378         if ((err = i2c_detach_client(client)))
 379                 return err;
 380
 381         list_del(&data->list);
 382         kfree(data);
 383         return 0;
 384 }
 385
 386 static int __init ds1337_init(void)
 387 {
 388         return i2c_add_driver(&ds1337_driver);
 389 }
 390
 391 static void __exit ds1337_exit(void)
 392 {
 393         i2c_del_driver(&ds1337_driver);
 394 }
 395
 396 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 397 MODULE_DESCRIPTION("DS1337 RTC driver");
 398 MODULE_LICENSE("GPL");
 399
 400 EXPORT_SYMBOL_GPL(ds1337_do_command);
 401
 402 module_init(ds1337_init);
 403 module_exit(ds1337_exit);