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