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 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04)); 31 32 /* Allow the strong pullup to be disabled, but default to enabled. 33 * If it was disabled a parasite powered device might not get the required 34 * current to copy the data from the scratchpad to EEPROM. If it is enabled 35 * parasite powered devices have a better chance of getting the current 36 * required. 37 */ 38 static int w1_strong_pullup = 1; 39 module_param_named(strong_pullup, w1_strong_pullup, int, 0); 40 41 /* enable/disable CRC checking on DS28E04-100 memory accesses */ 42 static char w1_enable_crccheck = 1; 43 44 #define W1_EEPROM_SIZE 512 45 #define W1_PAGE_COUNT 16 46 #define W1_PAGE_SIZE 32 47 #define W1_PAGE_BITS 5 48 #define W1_PAGE_MASK 0x1F 49 50 #define W1_F1C_READ_EEPROM 0xF0 51 #define W1_F1C_WRITE_SCRATCH 0x0F 52 #define W1_F1C_READ_SCRATCH 0xAA 53 #define W1_F1C_COPY_SCRATCH 0x55 54 #define W1_F1C_ACCESS_WRITE 0x5A 55 56 #define W1_1C_REG_LOGIC_STATE 0x220 57 58 struct w1_f1C_data { 59 u8 memory[W1_EEPROM_SIZE]; 60 u32 validcrc; 61 }; 62 63 /** 64 * Check the file size bounds and adjusts count as needed. 65 * This would not be needed if the file size didn't reset to 0 after a write. 66 */ 67 static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size) 68 { 69 if (off > size) 70 return 0; 71 72 if ((off + count) > size) 73 return size - off; 74 75 return count; 76 } 77 78 static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data, 79 int block) 80 { 81 u8 wrbuf[3]; 82 int off = block * W1_PAGE_SIZE; 83 84 if (data->validcrc & (1 << block)) 85 return 0; 86 87 if (w1_reset_select_slave(sl)) { 88 data->validcrc = 0; 89 return -EIO; 90 } 91 92 wrbuf[0] = W1_F1C_READ_EEPROM; 93 wrbuf[1] = off & 0xff; 94 wrbuf[2] = off >> 8; 95 w1_write_block(sl->master, wrbuf, 3); 96 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); 97 98 /* cache the block if the CRC is valid */ 99 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID) 100 data->validcrc |= (1 << block); 101 102 return 0; 103 } 104 105 static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data) 106 { 107 u8 wrbuf[3]; 108 109 /* read directly from the EEPROM */ 110 if (w1_reset_select_slave(sl)) 111 return -EIO; 112 113 wrbuf[0] = W1_F1C_READ_EEPROM; 114 wrbuf[1] = addr & 0xff; 115 wrbuf[2] = addr >> 8; 116 117 w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); 118 return w1_read_block(sl->master, data, len); 119 } 120 121 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, 122 struct bin_attribute *bin_attr, char *buf, 123 loff_t off, size_t count) 124 { 125 struct w1_slave *sl = kobj_to_w1_slave(kobj); 126 struct w1_f1C_data *data = sl->family_data; 127 int i, min_page, max_page; 128 129 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); 130 if (count == 0) 131 return 0; 132 133 mutex_lock(&sl->master->mutex); 134 135 if (w1_enable_crccheck) { 136 min_page = (off >> W1_PAGE_BITS); 137 max_page = (off + count - 1) >> W1_PAGE_BITS; 138 for (i = min_page; i <= max_page; i++) { 139 if (w1_f1C_refresh_block(sl, data, i)) { 140 count = -EIO; 141 goto out_up; 142 } 143 } 144 memcpy(buf, &data->memory[off], count); 145 } else { 146 count = w1_f1C_read(sl, off, count, buf); 147 } 148 149 out_up: 150 mutex_unlock(&sl->master->mutex); 151 152 return count; 153 } 154 155 /** 156 * Writes to the scratchpad and reads it back for verification. 157 * Then copies the scratchpad to EEPROM. 158 * The data must be on one page. 159 * The master must be locked. 160 * 161 * @param sl The slave structure 162 * @param addr Address for the write 163 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) 164 * @param data The data to write 165 * @return 0=Success -1=failure 166 */ 167 static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data) 168 { 169 u8 wrbuf[4]; 170 u8 rdbuf[W1_PAGE_SIZE + 3]; 171 u8 es = (addr + len - 1) & 0x1f; 172 unsigned int tm = 10; 173 int i; 174 struct w1_f1C_data *f1C = sl->family_data; 175 176 /* Write the data to the scratchpad */ 177 if (w1_reset_select_slave(sl)) 178 return -1; 179 180 wrbuf[0] = W1_F1C_WRITE_SCRATCH; 181 wrbuf[1] = addr & 0xff; 182 wrbuf[2] = addr >> 8; 183 184 w1_write_block(sl->master, wrbuf, 3); 185 w1_write_block(sl->master, data, len); 186 187 /* Read the scratchpad and verify */ 188 if (w1_reset_select_slave(sl)) 189 return -1; 190 191 w1_write_8(sl->master, W1_F1C_READ_SCRATCH); 192 w1_read_block(sl->master, rdbuf, len + 3); 193 194 /* Compare what was read against the data written */ 195 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || 196 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) 197 return -1; 198 199 /* Copy the scratchpad to EEPROM */ 200 if (w1_reset_select_slave(sl)) 201 return -1; 202 203 wrbuf[0] = W1_F1C_COPY_SCRATCH; 204 wrbuf[3] = es; 205 206 for (i = 0; i < sizeof(wrbuf); ++i) { 207 /* issue 10ms strong pullup (or delay) on the last byte 208 for writing the data from the scratchpad to EEPROM */ 209 if (w1_strong_pullup && i == sizeof(wrbuf)-1) 210 w1_next_pullup(sl->master, tm); 211 212 w1_write_8(sl->master, wrbuf[i]); 213 } 214 215 if (!w1_strong_pullup) 216 msleep(tm); 217 218 if (w1_enable_crccheck) { 219 /* invalidate cached data */ 220 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS)); 221 } 222 223 /* Reset the bus to wake up the EEPROM (this may not be needed) */ 224 w1_reset_bus(sl->master); 225 226 return 0; 227 } 228 229 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, 230 struct bin_attribute *bin_attr, char *buf, 231 loff_t off, size_t count) 232 233 { 234 struct w1_slave *sl = kobj_to_w1_slave(kobj); 235 int addr, len, idx; 236 237 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); 238 if (count == 0) 239 return 0; 240 241 if (w1_enable_crccheck) { 242 /* can only write full blocks in cached mode */ 243 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { 244 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", 245 (int)off, count); 246 return -EINVAL; 247 } 248 249 /* make sure the block CRCs are valid */ 250 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { 251 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) 252 != CRC16_VALID) { 253 dev_err(&sl->dev, "bad CRC at offset %d\n", 254 (int)off); 255 return -EINVAL; 256 } 257 } 258 } 259 260 mutex_lock(&sl->master->mutex); 261 262 /* Can only write data to one page at a time */ 263 idx = 0; 264 while (idx < count) { 265 addr = off + idx; 266 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); 267 if (len > (count - idx)) 268 len = count - idx; 269 270 if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) { 271 count = -EIO; 272 goto out_up; 273 } 274 idx += len; 275 } 276 277 out_up: 278 mutex_unlock(&sl->master->mutex); 279 280 return count; 281 } 282 283 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE); 284 285 static ssize_t pio_read(struct file *filp, struct kobject *kobj, 286 struct bin_attribute *bin_attr, char *buf, loff_t off, 287 size_t count) 288 289 { 290 struct w1_slave *sl = kobj_to_w1_slave(kobj); 291 int ret; 292 293 /* check arguments */ 294 if (off != 0 || count != 1 || buf == NULL) 295 return -EINVAL; 296 297 mutex_lock(&sl->master->mutex); 298 ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf); 299 mutex_unlock(&sl->master->mutex); 300 301 return ret; 302 } 303 304 static ssize_t pio_write(struct file *filp, struct kobject *kobj, 305 struct bin_attribute *bin_attr, char *buf, loff_t off, 306 size_t count) 307 308 { 309 struct w1_slave *sl = kobj_to_w1_slave(kobj); 310 u8 wrbuf[3]; 311 u8 ack; 312 313 /* check arguments */ 314 if (off != 0 || count != 1 || buf == NULL) 315 return -EINVAL; 316 317 mutex_lock(&sl->master->mutex); 318 319 /* Write the PIO data */ 320 if (w1_reset_select_slave(sl)) { 321 mutex_unlock(&sl->master->mutex); 322 return -1; 323 } 324 325 /* set bit 7..2 to value '1' */ 326 *buf = *buf | 0xFC; 327 328 wrbuf[0] = W1_F1C_ACCESS_WRITE; 329 wrbuf[1] = *buf; 330 wrbuf[2] = ~(*buf); 331 w1_write_block(sl->master, wrbuf, 3); 332 333 w1_read_block(sl->master, &ack, sizeof(ack)); 334 335 mutex_unlock(&sl->master->mutex); 336 337 /* check for acknowledgement */ 338 if (ack != 0xAA) 339 return -EIO; 340 341 return count; 342 } 343 344 static BIN_ATTR_RW(pio, 1); 345 346 static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr, 347 char *buf) 348 { 349 if (put_user(w1_enable_crccheck + 0x30, buf)) 350 return -EFAULT; 351 352 return sizeof(w1_enable_crccheck); 353 } 354 355 static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, 356 const char *buf, size_t count) 357 { 358 char val; 359 360 if (count != 1 || !buf) 361 return -EINVAL; 362 363 if (get_user(val, buf)) 364 return -EFAULT; 365 366 /* convert to decimal */ 367 val = val - 0x30; 368 if (val != 0 && val != 1) 369 return -EINVAL; 370 371 /* set the new value */ 372 w1_enable_crccheck = val; 373 374 return sizeof(w1_enable_crccheck); 375 } 376 377 static DEVICE_ATTR_RW(crccheck); 378 379 static struct attribute *w1_f1C_attrs[] = { 380 &dev_attr_crccheck.attr, 381 NULL, 382 }; 383 384 static struct bin_attribute *w1_f1C_bin_attrs[] = { 385 &bin_attr_eeprom, 386 &bin_attr_pio, 387 NULL, 388 }; 389 390 static const struct attribute_group w1_f1C_group = { 391 .attrs = w1_f1C_attrs, 392 .bin_attrs = w1_f1C_bin_attrs, 393 }; 394 395 static const struct attribute_group *w1_f1C_groups[] = { 396 &w1_f1C_group, 397 NULL, 398 }; 399 400 static int w1_f1C_add_slave(struct w1_slave *sl) 401 { 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 return 0; 412 } 413 414 static void w1_f1C_remove_slave(struct w1_slave *sl) 415 { 416 kfree(sl->family_data); 417 sl->family_data = NULL; 418 } 419 420 static struct w1_family_ops w1_f1C_fops = { 421 .add_slave = w1_f1C_add_slave, 422 .remove_slave = w1_f1C_remove_slave, 423 .groups = w1_f1C_groups, 424 }; 425 426 static struct w1_family w1_family_1C = { 427 .fid = W1_FAMILY_DS28E04, 428 .fops = &w1_f1C_fops, 429 }; 430 431 static int __init w1_f1C_init(void) 432 { 433 return w1_register_family(&w1_family_1C); 434 } 435 436 static void __exit w1_f1C_fini(void) 437 { 438 w1_unregister_family(&w1_family_1C); 439 } 440 441 module_init(w1_f1C_init); 442 module_exit(w1_f1C_fini); 443