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