1 /* 2 * w1_ds28e04.c - w1 family 1C (DS28E04) driver 3 * 4 * Copyright (c) 2012 Markus Franke <franke.m@sebakmt.com> 5 * 6 * This source code is licensed under the GNU General Public License, 7 * Version 2. See the file COPYING for more details. 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/moduleparam.h> 13 #include <linux/device.h> 14 #include <linux/types.h> 15 #include <linux/delay.h> 16 #include <linux/slab.h> 17 #include <linux/crc16.h> 18 #include <linux/uaccess.h> 19 20 #define CRC16_INIT 0 21 #define CRC16_VALID 0xb001 22 23 #include "../w1.h" 24 #include "../w1_int.h" 25 #include "../w1_family.h" 26 27 MODULE_LICENSE("GPL"); 28 MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>"); 29 MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO"); 30 31 /* Allow the strong pullup to be disabled, but default to enabled. 32 * If it was disabled a parasite powered device might not get the required 33 * current to copy the data from the scratchpad to EEPROM. If it is enabled 34 * parasite powered devices have a better chance of getting the current 35 * required. 36 */ 37 static int w1_strong_pullup = 1; 38 module_param_named(strong_pullup, w1_strong_pullup, int, 0); 39 40 /* enable/disable CRC checking on DS28E04-100 memory accesses */ 41 static char w1_enable_crccheck = 1; 42 43 #define W1_EEPROM_SIZE 512 44 #define W1_PAGE_COUNT 16 45 #define W1_PAGE_SIZE 32 46 #define W1_PAGE_BITS 5 47 #define W1_PAGE_MASK 0x1F 48 49 #define W1_F1C_READ_EEPROM 0xF0 50 #define W1_F1C_WRITE_SCRATCH 0x0F 51 #define W1_F1C_READ_SCRATCH 0xAA 52 #define W1_F1C_COPY_SCRATCH 0x55 53 #define W1_F1C_ACCESS_WRITE 0x5A 54 55 #define W1_1C_REG_LOGIC_STATE 0x220 56 57 struct w1_f1C_data { 58 u8 memory[W1_EEPROM_SIZE]; 59 u32 validcrc; 60 }; 61 62 /** 63 * Check the file size bounds and adjusts count as needed. 64 * This would not be needed if the file size didn't reset to 0 after a write. 65 */ 66 static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size) 67 { 68 if (off > size) 69 return 0; 70 71 if ((off + count) > size) 72 return size - off; 73 74 return count; 75 } 76 77 static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data, 78 int block) 79 { 80 u8 wrbuf[3]; 81 int off = block * W1_PAGE_SIZE; 82 83 if (data->validcrc & (1 << block)) 84 return 0; 85 86 if (w1_reset_select_slave(sl)) { 87 data->validcrc = 0; 88 return -EIO; 89 } 90 91 wrbuf[0] = W1_F1C_READ_EEPROM; 92 wrbuf[1] = off & 0xff; 93 wrbuf[2] = off >> 8; 94 w1_write_block(sl->master, wrbuf, 3); 95 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); 96 97 /* cache the block if the CRC is valid */ 98 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID) 99 data->validcrc |= (1 << block); 100 101 return 0; 102 } 103 104 static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data) 105 { 106 u8 wrbuf[3]; 107 108 /* read directly from the EEPROM */ 109 if (w1_reset_select_slave(sl)) 110 return -EIO; 111 112 wrbuf[0] = W1_F1C_READ_EEPROM; 113 wrbuf[1] = addr & 0xff; 114 wrbuf[2] = addr >> 8; 115 116 w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); 117 return w1_read_block(sl->master, data, len); 118 } 119 120 static ssize_t w1_f1C_read_bin(struct file *filp, struct kobject *kobj, 121 struct bin_attribute *bin_attr, 122 char *buf, loff_t off, size_t count) 123 { 124 struct w1_slave *sl = kobj_to_w1_slave(kobj); 125 struct w1_f1C_data *data = sl->family_data; 126 int i, min_page, max_page; 127 128 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); 129 if (count == 0) 130 return 0; 131 132 mutex_lock(&sl->master->mutex); 133 134 if (w1_enable_crccheck) { 135 min_page = (off >> W1_PAGE_BITS); 136 max_page = (off + count - 1) >> W1_PAGE_BITS; 137 for (i = min_page; i <= max_page; i++) { 138 if (w1_f1C_refresh_block(sl, data, i)) { 139 count = -EIO; 140 goto out_up; 141 } 142 } 143 memcpy(buf, &data->memory[off], count); 144 } else { 145 count = w1_f1C_read(sl, off, count, buf); 146 } 147 148 out_up: 149 mutex_unlock(&sl->master->mutex); 150 151 return count; 152 } 153 154 /** 155 * Writes to the scratchpad and reads it back for verification. 156 * Then copies the scratchpad to EEPROM. 157 * The data must be on one page. 158 * The master must be locked. 159 * 160 * @param sl The slave structure 161 * @param addr Address for the write 162 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) 163 * @param data The data to write 164 * @return 0=Success -1=failure 165 */ 166 static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data) 167 { 168 u8 wrbuf[4]; 169 u8 rdbuf[W1_PAGE_SIZE + 3]; 170 u8 es = (addr + len - 1) & 0x1f; 171 unsigned int tm = 10; 172 int i; 173 struct w1_f1C_data *f1C = sl->family_data; 174 175 /* Write the data to the scratchpad */ 176 if (w1_reset_select_slave(sl)) 177 return -1; 178 179 wrbuf[0] = W1_F1C_WRITE_SCRATCH; 180 wrbuf[1] = addr & 0xff; 181 wrbuf[2] = addr >> 8; 182 183 w1_write_block(sl->master, wrbuf, 3); 184 w1_write_block(sl->master, data, len); 185 186 /* Read the scratchpad and verify */ 187 if (w1_reset_select_slave(sl)) 188 return -1; 189 190 w1_write_8(sl->master, W1_F1C_READ_SCRATCH); 191 w1_read_block(sl->master, rdbuf, len + 3); 192 193 /* Compare what was read against the data written */ 194 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || 195 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) 196 return -1; 197 198 /* Copy the scratchpad to EEPROM */ 199 if (w1_reset_select_slave(sl)) 200 return -1; 201 202 wrbuf[0] = W1_F1C_COPY_SCRATCH; 203 wrbuf[3] = es; 204 205 for (i = 0; i < sizeof(wrbuf); ++i) { 206 /* issue 10ms strong pullup (or delay) on the last byte 207 for writing the data from the scratchpad to EEPROM */ 208 if (w1_strong_pullup && i == sizeof(wrbuf)-1) 209 w1_next_pullup(sl->master, tm); 210 211 w1_write_8(sl->master, wrbuf[i]); 212 } 213 214 if (!w1_strong_pullup) 215 msleep(tm); 216 217 if (w1_enable_crccheck) { 218 /* invalidate cached data */ 219 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS)); 220 } 221 222 /* Reset the bus to wake up the EEPROM (this may not be needed) */ 223 w1_reset_bus(sl->master); 224 225 return 0; 226 } 227 228 static ssize_t w1_f1C_write_bin(struct file *filp, struct kobject *kobj, 229 struct bin_attribute *bin_attr, 230 char *buf, loff_t off, size_t count) 231 232 { 233 struct w1_slave *sl = kobj_to_w1_slave(kobj); 234 int addr, len, idx; 235 236 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); 237 if (count == 0) 238 return 0; 239 240 if (w1_enable_crccheck) { 241 /* can only write full blocks in cached mode */ 242 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { 243 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", 244 (int)off, count); 245 return -EINVAL; 246 } 247 248 /* make sure the block CRCs are valid */ 249 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { 250 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) 251 != CRC16_VALID) { 252 dev_err(&sl->dev, "bad CRC at offset %d\n", 253 (int)off); 254 return -EINVAL; 255 } 256 } 257 } 258 259 mutex_lock(&sl->master->mutex); 260 261 /* Can only write data to one page at a time */ 262 idx = 0; 263 while (idx < count) { 264 addr = off + idx; 265 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); 266 if (len > (count - idx)) 267 len = count - idx; 268 269 if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) { 270 count = -EIO; 271 goto out_up; 272 } 273 idx += len; 274 } 275 276 out_up: 277 mutex_unlock(&sl->master->mutex); 278 279 return count; 280 } 281 282 static ssize_t w1_f1C_read_pio(struct file *filp, struct kobject *kobj, 283 struct bin_attribute *bin_attr, 284 char *buf, loff_t off, size_t count) 285 286 { 287 struct w1_slave *sl = kobj_to_w1_slave(kobj); 288 int ret; 289 290 /* check arguments */ 291 if (off != 0 || count != 1 || buf == NULL) 292 return -EINVAL; 293 294 mutex_lock(&sl->master->mutex); 295 ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf); 296 mutex_unlock(&sl->master->mutex); 297 298 return ret; 299 } 300 301 static ssize_t w1_f1C_write_pio(struct file *filp, struct kobject *kobj, 302 struct bin_attribute *bin_attr, 303 char *buf, loff_t off, size_t count) 304 305 { 306 struct w1_slave *sl = kobj_to_w1_slave(kobj); 307 u8 wrbuf[3]; 308 u8 ack; 309 310 /* check arguments */ 311 if (off != 0 || count != 1 || buf == NULL) 312 return -EINVAL; 313 314 mutex_lock(&sl->master->mutex); 315 316 /* Write the PIO data */ 317 if (w1_reset_select_slave(sl)) { 318 mutex_unlock(&sl->master->mutex); 319 return -1; 320 } 321 322 /* set bit 7..2 to value '1' */ 323 *buf = *buf | 0xFC; 324 325 wrbuf[0] = W1_F1C_ACCESS_WRITE; 326 wrbuf[1] = *buf; 327 wrbuf[2] = ~(*buf); 328 w1_write_block(sl->master, wrbuf, 3); 329 330 w1_read_block(sl->master, &ack, sizeof(ack)); 331 332 mutex_unlock(&sl->master->mutex); 333 334 /* check for acknowledgement */ 335 if (ack != 0xAA) 336 return -EIO; 337 338 return count; 339 } 340 341 static ssize_t w1_f1C_show_crccheck(struct device *dev, 342 struct device_attribute *attr, char *buf) 343 { 344 if (put_user(w1_enable_crccheck + 0x30, buf)) 345 return -EFAULT; 346 347 return sizeof(w1_enable_crccheck); 348 } 349 350 static ssize_t w1_f1C_store_crccheck(struct device *dev, 351 struct device_attribute *attr, 352 const char *buf, size_t count) 353 { 354 char val; 355 356 if (count != 1 || !buf) 357 return -EINVAL; 358 359 if (get_user(val, buf)) 360 return -EFAULT; 361 362 /* convert to decimal */ 363 val = val - 0x30; 364 if (val != 0 && val != 1) 365 return -EINVAL; 366 367 /* set the new value */ 368 w1_enable_crccheck = val; 369 370 return sizeof(w1_enable_crccheck); 371 } 372 373 #define NB_SYSFS_BIN_FILES 2 374 static struct bin_attribute w1_f1C_bin_attr[NB_SYSFS_BIN_FILES] = { 375 { 376 .attr = { 377 .name = "eeprom", 378 .mode = S_IRUGO | S_IWUSR, 379 }, 380 .size = W1_EEPROM_SIZE, 381 .read = w1_f1C_read_bin, 382 .write = w1_f1C_write_bin, 383 }, 384 { 385 .attr = { 386 .name = "pio", 387 .mode = S_IRUGO | S_IWUSR, 388 }, 389 .size = 1, 390 .read = w1_f1C_read_pio, 391 .write = w1_f1C_write_pio, 392 } 393 }; 394 395 static DEVICE_ATTR(crccheck, S_IWUSR | S_IRUGO, 396 w1_f1C_show_crccheck, w1_f1C_store_crccheck); 397 398 static int w1_f1C_add_slave(struct w1_slave *sl) 399 { 400 int err = 0; 401 int i; 402 struct w1_f1C_data *data = NULL; 403 404 if (w1_enable_crccheck) { 405 data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL); 406 if (!data) 407 return -ENOMEM; 408 sl->family_data = data; 409 } 410 411 /* create binary sysfs attributes */ 412 for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i) 413 err = sysfs_create_bin_file( 414 &sl->dev.kobj, &(w1_f1C_bin_attr[i])); 415 416 if (!err) { 417 /* create device attributes */ 418 err = device_create_file(&sl->dev, &dev_attr_crccheck); 419 } 420 421 if (err) { 422 /* remove binary sysfs attributes */ 423 for (i = 0; i < NB_SYSFS_BIN_FILES; ++i) 424 sysfs_remove_bin_file( 425 &sl->dev.kobj, &(w1_f1C_bin_attr[i])); 426 427 kfree(data); 428 } 429 430 return err; 431 } 432 433 static void w1_f1C_remove_slave(struct w1_slave *sl) 434 { 435 int i; 436 437 kfree(sl->family_data); 438 sl->family_data = NULL; 439 440 /* remove device attributes */ 441 device_remove_file(&sl->dev, &dev_attr_crccheck); 442 443 /* remove binary sysfs attributes */ 444 for (i = 0; i < NB_SYSFS_BIN_FILES; ++i) 445 sysfs_remove_bin_file(&sl->dev.kobj, &(w1_f1C_bin_attr[i])); 446 } 447 448 static struct w1_family_ops w1_f1C_fops = { 449 .add_slave = w1_f1C_add_slave, 450 .remove_slave = w1_f1C_remove_slave, 451 }; 452 453 static struct w1_family w1_family_1C = { 454 .fid = W1_FAMILY_DS28E04, 455 .fops = &w1_f1C_fops, 456 }; 457 458 static int __init w1_f1C_init(void) 459 { 460 return w1_register_family(&w1_family_1C); 461 } 462 463 static void __exit w1_f1C_fini(void) 464 { 465 w1_unregister_family(&w1_family_1C); 466 } 467 468 module_init(w1_f1C_init); 469 module_exit(w1_f1C_fini); 470