kernel/drivers/w1/slaves/w1_therm.c

   1 /*
   2  *      w1_therm.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the therms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <asm/types.h>
  23
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/sched.h>
  28 #include <linux/device.h>
  29 #include <linux/types.h>
  30 #include <linux/slab.h>
  31 #include <linux/delay.h>
  32
  33 #include "../w1.h"
  34 #include "../w1_int.h"
  35 #include "../w1_family.h"
  36
  37 MODULE_LICENSE("GPL");
  38 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
  39 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
  40 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20));
  41 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822));
  42 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20));
  43 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825));
  44 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));
  45
  46 /* Allow the strong pullup to be disabled, but default to enabled.
  47  * If it was disabled a parasite powered device might not get the require
  48  * current to do a temperature conversion.  If it is enabled parasite powered
  49  * devices have a better chance of getting the current required.
  50  * In case the parasite power-detection is not working (seems to be the case
  51  * for some DS18S20) the strong pullup can also be forced, regardless of the
  52  * power state of the devices.
  53  *
  54  * Summary of options:
  55  * - strong_pullup = 0  Disable strong pullup completely
  56  * - strong_pullup = 1  Enable automatic strong pullup detection
  57  * - strong_pullup = 2  Force strong pullup
  58  */
  59 static int w1_strong_pullup = 1;
  60 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
  61
  62 struct w1_therm_family_data {
  63         uint8_t rom[9];
  64         atomic_t refcnt;
  65 };
  66
  67 /* return the address of the refcnt in the family data */
  68 #define THERM_REFCNT(family_data) \
  69         (&((struct w1_therm_family_data*)family_data)->refcnt)
  70
  71 static int w1_therm_add_slave(struct w1_slave *sl)
  72 {
  73         sl->family_data = kzalloc(sizeof(struct w1_therm_family_data),
  74                 GFP_KERNEL);
  75         if (!sl->family_data)
  76                 return -ENOMEM;
  77         atomic_set(THERM_REFCNT(sl->family_data), 1);
  78         return 0;
  79 }
  80
  81 static void w1_therm_remove_slave(struct w1_slave *sl)
  82 {
  83         int refcnt = atomic_sub_return(1, THERM_REFCNT(sl->family_data));
  84         while(refcnt) {
  85                 msleep(1000);
  86                 refcnt = atomic_read(THERM_REFCNT(sl->family_data));
  87         }
  88         kfree(sl->family_data);
  89         sl->family_data = NULL;
  90 }
  91
  92 static ssize_t w1_slave_show(struct device *device,
  93         struct device_attribute *attr, char *buf);
  94
  95 static ssize_t w1_seq_show(struct device *device,
  96         struct device_attribute *attr, char *buf);
  97
  98 static DEVICE_ATTR_RO(w1_slave);
  99 static DEVICE_ATTR_RO(w1_seq);
 100
 101 static struct attribute *w1_therm_attrs[] = {
 102         &dev_attr_w1_slave.attr,
 103         NULL,
 104 };
 105
 106 static struct attribute *w1_ds28ea00_attrs[] = {
 107         &dev_attr_w1_slave.attr,
 108         &dev_attr_w1_seq.attr,
 109         NULL,
 110 };
 111 ATTRIBUTE_GROUPS(w1_therm);
 112 ATTRIBUTE_GROUPS(w1_ds28ea00);
 113
 114 static struct w1_family_ops w1_therm_fops = {
 115         .add_slave      = w1_therm_add_slave,
 116         .remove_slave   = w1_therm_remove_slave,
 117         .groups         = w1_therm_groups,
 118 };
 119
 120 static struct w1_family_ops w1_ds28ea00_fops = {
 121         .add_slave      = w1_therm_add_slave,
 122         .remove_slave   = w1_therm_remove_slave,
 123         .groups         = w1_ds28ea00_groups,
 124 };
 125
 126 static struct w1_family w1_therm_family_DS18S20 = {
 127         .fid = W1_THERM_DS18S20,
 128         .fops = &w1_therm_fops,
 129 };
 130
 131 static struct w1_family w1_therm_family_DS18B20 = {
 132         .fid = W1_THERM_DS18B20,
 133         .fops = &w1_therm_fops,
 134 };
 135
 136 static struct w1_family w1_therm_family_DS1822 = {
 137         .fid = W1_THERM_DS1822,
 138         .fops = &w1_therm_fops,
 139 };
 140
 141 static struct w1_family w1_therm_family_DS28EA00 = {
 142         .fid = W1_THERM_DS28EA00,
 143         .fops = &w1_ds28ea00_fops,
 144 };
 145
 146 static struct w1_family w1_therm_family_DS1825 = {
 147         .fid = W1_THERM_DS1825,
 148         .fops = &w1_therm_fops,
 149 };
 150
 151 struct w1_therm_family_converter
 152 {
 153         u8                      broken;
 154         u16                     reserved;
 155         struct w1_family        *f;
 156         int                     (*convert)(u8 rom[9]);
 157 };
 158
 159 /* The return value is millidegrees Centigrade. */
 160 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
 161 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
 162
 163 static struct w1_therm_family_converter w1_therm_families[] = {
 164         {
 165                 .f              = &w1_therm_family_DS18S20,
 166                 .convert        = w1_DS18S20_convert_temp
 167         },
 168         {
 169                 .f              = &w1_therm_family_DS1822,
 170                 .convert        = w1_DS18B20_convert_temp
 171         },
 172         {
 173                 .f              = &w1_therm_family_DS18B20,
 174                 .convert        = w1_DS18B20_convert_temp
 175         },
 176         {
 177                 .f              = &w1_therm_family_DS28EA00,
 178                 .convert        = w1_DS18B20_convert_temp
 179         },
 180         {
 181                 .f              = &w1_therm_family_DS1825,
 182                 .convert        = w1_DS18B20_convert_temp
 183         }
 184 };
 185
 186 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 187 {
 188         s16 t = le16_to_cpup((__le16 *)rom);
 189         return t*1000/16;
 190 }
 191
 192 static inline int w1_DS18S20_convert_temp(u8 rom[9])
 193 {
 194         int t, h;
 195
 196         if (!rom[7])
 197                 return 0;
 198
 199         if (rom[1] == 0)
 200                 t = ((s32)rom[0] >> 1)*1000;
 201         else
 202                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
 203
 204         t -= 250;
 205         h = 1000*((s32)rom[7] - (s32)rom[6]);
 206         h /= (s32)rom[7];
 207         t += h;
 208
 209         return t;
 210 }
 211
 212 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 213 {
 214         int i;
 215
 216         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
 217                 if (w1_therm_families[i].f->fid == fid)
 218                         return w1_therm_families[i].convert(rom);
 219
 220         return 0;
 221 }
 222
 223
 224 static ssize_t w1_slave_show(struct device *device,
 225         struct device_attribute *attr, char *buf)
 226 {
 227         struct w1_slave *sl = dev_to_w1_slave(device);
 228         struct w1_master *dev = sl->master;
 229         u8 rom[9], crc, verdict, external_power;
 230         int i, ret, max_trying = 10;
 231         ssize_t c = PAGE_SIZE;
 232         u8 *family_data = sl->family_data;
 233
 234         ret = mutex_lock_interruptible(&dev->bus_mutex);
 235         if (ret != 0)
 236                 goto post_unlock;
 237
 238         if(!sl->family_data)
 239         {
 240                 ret = -ENODEV;
 241                 goto pre_unlock;
 242         }
 243
 244         /* prevent the slave from going away in sleep */
 245         atomic_inc(THERM_REFCNT(family_data));
 246         memset(rom, 0, sizeof(rom));
 247
 248         while (max_trying--) {
 249
 250                 verdict = 0;
 251                 crc = 0;
 252
 253                 if (!w1_reset_select_slave(sl)) {
 254                         int count = 0;
 255                         unsigned int tm = 750;
 256                         unsigned long sleep_rem;
 257
 258                         w1_write_8(dev, W1_READ_PSUPPLY);
 259                         external_power = w1_read_8(dev);
 260
 261                         if (w1_reset_select_slave(sl))
 262                                 continue;
 263
 264                         /* 750ms strong pullup (or delay) after the convert */
 265                         if (w1_strong_pullup == 2 ||
 266                                         (!external_power && w1_strong_pullup))
 267                                 w1_next_pullup(dev, tm);
 268
 269                         w1_write_8(dev, W1_CONVERT_TEMP);
 270
 271                         if (external_power) {
 272                                 mutex_unlock(&dev->bus_mutex);
 273
 274                                 sleep_rem = msleep_interruptible(tm);
 275                                 if (sleep_rem != 0) {
 276                                         ret = -EINTR;
 277                                         goto post_unlock;
 278                                 }
 279
 280                                 ret = mutex_lock_interruptible(&dev->bus_mutex);
 281                                 if (ret != 0)
 282                                         goto post_unlock;
 283                         } else if (!w1_strong_pullup) {
 284                                 sleep_rem = msleep_interruptible(tm);
 285                                 if (sleep_rem != 0) {
 286                                         ret = -EINTR;
 287                                         goto pre_unlock;
 288                                 }
 289                         }
 290
 291                         if (!w1_reset_select_slave(sl)) {
 292
 293                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 294                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 295                                         dev_warn(device, "w1_read_block() "
 296                                                 "returned %u instead of 9.\n",
 297                                                 count);
 298                                 }
 299
 300                                 crc = w1_calc_crc8(rom, 8);
 301
 302                                 if (rom[8] == crc)
 303                                         verdict = 1;
 304                         }
 305                 }
 306
 307                 if (verdict)
 308                         break;
 309         }
 310
 311         for (i = 0; i < 9; ++i)
 312                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
 313         c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
 314                            crc, (verdict) ? "YES" : "NO");
 315         if (verdict)
 316                 memcpy(family_data, rom, sizeof(rom));
 317         else
 318                 dev_warn(device, "Read failed CRC check\n");
 319
 320         for (i = 0; i < 9; ++i)
 321                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
 322                               ((u8 *)family_data)[i]);
 323
 324         c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
 325                 w1_convert_temp(rom, sl->family->fid));
 326         ret = PAGE_SIZE - c;
 327
 328 pre_unlock:
 329         mutex_unlock(&dev->bus_mutex);
 330
 331 post_unlock:
 332         atomic_dec(THERM_REFCNT(family_data));
 333         return ret;
 334 }
 335
 336 #define W1_42_CHAIN     0x99
 337 #define W1_42_CHAIN_OFF 0x3C
 338 #define W1_42_CHAIN_OFF_INV     0xC3
 339 #define W1_42_CHAIN_ON  0x5A
 340 #define W1_42_CHAIN_ON_INV      0xA5
 341 #define W1_42_CHAIN_DONE 0x96
 342 #define W1_42_CHAIN_DONE_INV 0x69
 343 #define W1_42_COND_READ 0x0F
 344 #define W1_42_SUCCESS_CONFIRM_BYTE 0xAA
 345 #define W1_42_FINISHED_BYTE 0xFF
 346 static ssize_t w1_seq_show(struct device *device,
 347         struct device_attribute *attr, char *buf)
 348 {
 349         struct w1_slave *sl = dev_to_w1_slave(device);
 350         ssize_t c = PAGE_SIZE;
 351         int rv;
 352         int i;
 353         u8 ack;
 354         u64 rn;
 355         struct w1_reg_num *reg_num;
 356         int seq = 0;
 357
 358         mutex_lock(&sl->master->bus_mutex);
 359         /* Place all devices in CHAIN state */
 360         if (w1_reset_bus(sl->master))
 361                 goto error;
 362         w1_write_8(sl->master, W1_SKIP_ROM);
 363         w1_write_8(sl->master, W1_42_CHAIN);
 364         w1_write_8(sl->master, W1_42_CHAIN_ON);
 365         w1_write_8(sl->master, W1_42_CHAIN_ON_INV);
 366         msleep(sl->master->pullup_duration);
 367
 368         /* check for acknowledgment */
 369         ack = w1_read_8(sl->master);
 370         if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
 371                 goto error;
 372
 373         /* In case the bus fails to send 0xFF, limit*/
 374         for (i = 0; i <= 64; i++) {
 375                 if (w1_reset_bus(sl->master))
 376                         goto error;
 377
 378                 w1_write_8(sl->master, W1_42_COND_READ);
 379                 rv = w1_read_block(sl->master, (u8 *)&rn, 8);
 380                 reg_num = (struct w1_reg_num *) &rn;
 381                 if (reg_num->family == W1_42_FINISHED_BYTE)
 382                         break;
 383                 if (sl->reg_num.id == reg_num->id)
 384                         seq = i;
 385
 386                 w1_write_8(sl->master, W1_42_CHAIN);
 387                 w1_write_8(sl->master, W1_42_CHAIN_DONE);
 388                 w1_write_8(sl->master, W1_42_CHAIN_DONE_INV);
 389                 w1_read_block(sl->master, &ack, sizeof(ack));
 390
 391                 /* check for acknowledgment */
 392                 ack = w1_read_8(sl->master);
 393                 if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
 394                         goto error;
 395
 396         }
 397
 398         /* Exit from CHAIN state */
 399         if (w1_reset_bus(sl->master))
 400                 goto error;
 401         w1_write_8(sl->master, W1_SKIP_ROM);
 402         w1_write_8(sl->master, W1_42_CHAIN);
 403         w1_write_8(sl->master, W1_42_CHAIN_OFF);
 404         w1_write_8(sl->master, W1_42_CHAIN_OFF_INV);
 405
 406         /* check for acknowledgment */
 407         ack = w1_read_8(sl->master);
 408         if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
 409                 goto error;
 410         mutex_unlock(&sl->master->bus_mutex);
 411
 412         c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq);
 413         return PAGE_SIZE - c;
 414 error:
 415         mutex_unlock(&sl->master->bus_mutex);
 416         return -EIO;
 417 }
 418
 419 static int __init w1_therm_init(void)
 420 {
 421         int err, i;
 422
 423         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
 424                 err = w1_register_family(w1_therm_families[i].f);
 425                 if (err)
 426                         w1_therm_families[i].broken = 1;
 427         }
 428
 429         return 0;
 430 }
 431
 432 static void __exit w1_therm_fini(void)
 433 {
 434         int i;
 435
 436         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
 437                 if (!w1_therm_families[i].broken)
 438                         w1_unregister_family(w1_therm_families[i].f);
 439 }
 440
 441 module_init(w1_therm_init);
 442 module_exit(w1_therm_fini);