1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * w1_ds28e04.c - w1 family 1C (DS28E04) driver 4 * 5 * Copyright (c) 2012 Markus Franke <franke.m@sebakmt.com> 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/moduleparam.h> 11 #include <linux/device.h> 12 #include <linux/types.h> 13 #include <linux/delay.h> 14 #include <linux/slab.h> 15 #include <linux/crc16.h> 16 #include <linux/uaccess.h> 17 18 #define CRC16_INIT 0 19 #define CRC16_VALID 0xb001 20 21 #include <linux/w1.h> 22 23 #define W1_FAMILY_DS28E04 0x1C 24 25 /* Allow the strong pullup to be disabled, but default to enabled. 26 * If it was disabled a parasite powered device might not get the required 27 * current to copy the data from the scratchpad to EEPROM. If it is enabled 28 * parasite powered devices have a better chance of getting the current 29 * required. 30 */ 31 static int w1_strong_pullup = 1; 32 module_param_named(strong_pullup, w1_strong_pullup, int, 0); 33 34 /* enable/disable CRC checking on DS28E04-100 memory accesses */ 35 static char w1_enable_crccheck = 1; 36 37 #define W1_EEPROM_SIZE 512 38 #define W1_PAGE_COUNT 16 39 #define W1_PAGE_SIZE 32 40 #define W1_PAGE_BITS 5 41 #define W1_PAGE_MASK 0x1F 42 43 #define W1_F1C_READ_EEPROM 0xF0 44 #define W1_F1C_WRITE_SCRATCH 0x0F 45 #define W1_F1C_READ_SCRATCH 0xAA 46 #define W1_F1C_COPY_SCRATCH 0x55 47 #define W1_F1C_ACCESS_WRITE 0x5A 48 49 #define W1_1C_REG_LOGIC_STATE 0x220 50 51 struct w1_f1C_data { 52 u8 memory[W1_EEPROM_SIZE]; 53 u32 validcrc; 54 }; 55 56 /** 57 * Check the file size bounds and adjusts count as needed. 58 * This would not be needed if the file size didn't reset to 0 after a write. 59 */ 60 static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size) 61 { 62 if (off > size) 63 return 0; 64 65 if ((off + count) > size) 66 return size - off; 67 68 return count; 69 } 70 71 static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data, 72 int block) 73 { 74 u8 wrbuf[3]; 75 int off = block * W1_PAGE_SIZE; 76 77 if (data->validcrc & (1 << block)) 78 return 0; 79 80 if (w1_reset_select_slave(sl)) { 81 data->validcrc = 0; 82 return -EIO; 83 } 84 85 wrbuf[0] = W1_F1C_READ_EEPROM; 86 wrbuf[1] = off & 0xff; 87 wrbuf[2] = off >> 8; 88 w1_write_block(sl->master, wrbuf, 3); 89 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); 90 91 /* cache the block if the CRC is valid */ 92 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID) 93 data->validcrc |= (1 << block); 94 95 return 0; 96 } 97 98 static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data) 99 { 100 u8 wrbuf[3]; 101 102 /* read directly from the EEPROM */ 103 if (w1_reset_select_slave(sl)) 104 return -EIO; 105 106 wrbuf[0] = W1_F1C_READ_EEPROM; 107 wrbuf[1] = addr & 0xff; 108 wrbuf[2] = addr >> 8; 109 110 w1_write_block(sl->master, wrbuf, sizeof(wrbuf)); 111 return w1_read_block(sl->master, data, len); 112 } 113 114 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, 115 struct bin_attribute *bin_attr, char *buf, 116 loff_t off, size_t count) 117 { 118 struct w1_slave *sl = kobj_to_w1_slave(kobj); 119 struct w1_f1C_data *data = sl->family_data; 120 int i, min_page, max_page; 121 122 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); 123 if (count == 0) 124 return 0; 125 126 mutex_lock(&sl->master->mutex); 127 128 if (w1_enable_crccheck) { 129 min_page = (off >> W1_PAGE_BITS); 130 max_page = (off + count - 1) >> W1_PAGE_BITS; 131 for (i = min_page; i <= max_page; i++) { 132 if (w1_f1C_refresh_block(sl, data, i)) { 133 count = -EIO; 134 goto out_up; 135 } 136 } 137 memcpy(buf, &data->memory[off], count); 138 } else { 139 count = w1_f1C_read(sl, off, count, buf); 140 } 141 142 out_up: 143 mutex_unlock(&sl->master->mutex); 144 145 return count; 146 } 147 148 /** 149 * Writes to the scratchpad and reads it back for verification. 150 * Then copies the scratchpad to EEPROM. 151 * The data must be on one page. 152 * The master must be locked. 153 * 154 * @param sl The slave structure 155 * @param addr Address for the write 156 * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) 157 * @param data The data to write 158 * @return 0=Success -1=failure 159 */ 160 static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data) 161 { 162 u8 wrbuf[4]; 163 u8 rdbuf[W1_PAGE_SIZE + 3]; 164 u8 es = (addr + len - 1) & 0x1f; 165 unsigned int tm = 10; 166 int i; 167 struct w1_f1C_data *f1C = sl->family_data; 168 169 /* Write the data to the scratchpad */ 170 if (w1_reset_select_slave(sl)) 171 return -1; 172 173 wrbuf[0] = W1_F1C_WRITE_SCRATCH; 174 wrbuf[1] = addr & 0xff; 175 wrbuf[2] = addr >> 8; 176 177 w1_write_block(sl->master, wrbuf, 3); 178 w1_write_block(sl->master, data, len); 179 180 /* Read the scratchpad and verify */ 181 if (w1_reset_select_slave(sl)) 182 return -1; 183 184 w1_write_8(sl->master, W1_F1C_READ_SCRATCH); 185 w1_read_block(sl->master, rdbuf, len + 3); 186 187 /* Compare what was read against the data written */ 188 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || 189 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) 190 return -1; 191 192 /* Copy the scratchpad to EEPROM */ 193 if (w1_reset_select_slave(sl)) 194 return -1; 195 196 wrbuf[0] = W1_F1C_COPY_SCRATCH; 197 wrbuf[3] = es; 198 199 for (i = 0; i < sizeof(wrbuf); ++i) { 200 /* issue 10ms strong pullup (or delay) on the last byte 201 for writing the data from the scratchpad to EEPROM */ 202 if (w1_strong_pullup && i == sizeof(wrbuf)-1) 203 w1_next_pullup(sl->master, tm); 204 205 w1_write_8(sl->master, wrbuf[i]); 206 } 207 208 if (!w1_strong_pullup) 209 msleep(tm); 210 211 if (w1_enable_crccheck) { 212 /* invalidate cached data */ 213 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS)); 214 } 215 216 /* Reset the bus to wake up the EEPROM (this may not be needed) */ 217 w1_reset_bus(sl->master); 218 219 return 0; 220 } 221 222 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, 223 struct bin_attribute *bin_attr, char *buf, 224 loff_t off, size_t count) 225 226 { 227 struct w1_slave *sl = kobj_to_w1_slave(kobj); 228 int addr, len, idx; 229 230 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); 231 if (count == 0) 232 return 0; 233 234 if (w1_enable_crccheck) { 235 /* can only write full blocks in cached mode */ 236 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { 237 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", 238 (int)off, count); 239 return -EINVAL; 240 } 241 242 /* make sure the block CRCs are valid */ 243 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { 244 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) 245 != CRC16_VALID) { 246 dev_err(&sl->dev, "bad CRC at offset %d\n", 247 (int)off); 248 return -EINVAL; 249 } 250 } 251 } 252 253 mutex_lock(&sl->master->mutex); 254 255 /* Can only write data to one page at a time */ 256 idx = 0; 257 while (idx < count) { 258 addr = off + idx; 259 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); 260 if (len > (count - idx)) 261 len = count - idx; 262 263 if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) { 264 count = -EIO; 265 goto out_up; 266 } 267 idx += len; 268 } 269 270 out_up: 271 mutex_unlock(&sl->master->mutex); 272 273 return count; 274 } 275 276 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE); 277 278 static ssize_t pio_read(struct file *filp, struct kobject *kobj, 279 struct bin_attribute *bin_attr, char *buf, loff_t off, 280 size_t count) 281 282 { 283 struct w1_slave *sl = kobj_to_w1_slave(kobj); 284 int ret; 285 286 /* check arguments */ 287 if (off != 0 || count != 1 || buf == NULL) 288 return -EINVAL; 289 290 mutex_lock(&sl->master->mutex); 291 ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf); 292 mutex_unlock(&sl->master->mutex); 293 294 return ret; 295 } 296 297 static ssize_t pio_write(struct file *filp, struct kobject *kobj, 298 struct bin_attribute *bin_attr, char *buf, loff_t off, 299 size_t count) 300 301 { 302 struct w1_slave *sl = kobj_to_w1_slave(kobj); 303 u8 wrbuf[3]; 304 u8 ack; 305 306 /* check arguments */ 307 if (off != 0 || count != 1 || buf == NULL) 308 return -EINVAL; 309 310 mutex_lock(&sl->master->mutex); 311 312 /* Write the PIO data */ 313 if (w1_reset_select_slave(sl)) { 314 mutex_unlock(&sl->master->mutex); 315 return -1; 316 } 317 318 /* set bit 7..2 to value '1' */ 319 *buf = *buf | 0xFC; 320 321 wrbuf[0] = W1_F1C_ACCESS_WRITE; 322 wrbuf[1] = *buf; 323 wrbuf[2] = ~(*buf); 324 w1_write_block(sl->master, wrbuf, 3); 325 326 w1_read_block(sl->master, &ack, sizeof(ack)); 327 328 mutex_unlock(&sl->master->mutex); 329 330 /* check for acknowledgement */ 331 if (ack != 0xAA) 332 return -EIO; 333 334 return count; 335 } 336 337 static BIN_ATTR_RW(pio, 1); 338 339 static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr, 340 char *buf) 341 { 342 if (put_user(w1_enable_crccheck + 0x30, buf)) 343 return -EFAULT; 344 345 return sizeof(w1_enable_crccheck); 346 } 347 348 static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, 349 const char *buf, size_t count) 350 { 351 char val; 352 353 if (count != 1 || !buf) 354 return -EINVAL; 355 356 if (get_user(val, buf)) 357 return -EFAULT; 358 359 /* convert to decimal */ 360 val = val - 0x30; 361 if (val != 0 && val != 1) 362 return -EINVAL; 363 364 /* set the new value */ 365 w1_enable_crccheck = val; 366 367 return sizeof(w1_enable_crccheck); 368 } 369 370 static DEVICE_ATTR_RW(crccheck); 371 372 static struct attribute *w1_f1C_attrs[] = { 373 &dev_attr_crccheck.attr, 374 NULL, 375 }; 376 377 static struct bin_attribute *w1_f1C_bin_attrs[] = { 378 &bin_attr_eeprom, 379 &bin_attr_pio, 380 NULL, 381 }; 382 383 static const struct attribute_group w1_f1C_group = { 384 .attrs = w1_f1C_attrs, 385 .bin_attrs = w1_f1C_bin_attrs, 386 }; 387 388 static const struct attribute_group *w1_f1C_groups[] = { 389 &w1_f1C_group, 390 NULL, 391 }; 392 393 static int w1_f1C_add_slave(struct w1_slave *sl) 394 { 395 struct w1_f1C_data *data = NULL; 396 397 if (w1_enable_crccheck) { 398 data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL); 399 if (!data) 400 return -ENOMEM; 401 sl->family_data = data; 402 } 403 404 return 0; 405 } 406 407 static void w1_f1C_remove_slave(struct w1_slave *sl) 408 { 409 kfree(sl->family_data); 410 sl->family_data = NULL; 411 } 412 413 static const struct w1_family_ops w1_f1C_fops = { 414 .add_slave = w1_f1C_add_slave, 415 .remove_slave = w1_f1C_remove_slave, 416 .groups = w1_f1C_groups, 417 }; 418 419 static struct w1_family w1_family_1C = { 420 .fid = W1_FAMILY_DS28E04, 421 .fops = &w1_f1C_fops, 422 }; 423 module_w1_family(w1_family_1C); 424 425 MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>"); 426 MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO"); 427 MODULE_LICENSE("GPL"); 428 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04)); 429