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); 443