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 bool w1_enable_crccheck = true; 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 * w1_f1C_write() - Writes to the scratchpad and reads it back for verification. 150 * @sl: The slave structure 151 * @addr: Address for the write 152 * @len: length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) 153 * @data: The data to write 154 * 155 * Then copies the scratchpad to EEPROM. 156 * The data must be on one page. 157 * The master must be locked. 158 * 159 * Return: 0=Success, -1=failure 160 */ 161 static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data) 162 { 163 u8 wrbuf[4]; 164 u8 rdbuf[W1_PAGE_SIZE + 3]; 165 u8 es = (addr + len - 1) & 0x1f; 166 unsigned int tm = 10; 167 int i; 168 struct w1_f1C_data *f1C = sl->family_data; 169 170 /* Write the data to the scratchpad */ 171 if (w1_reset_select_slave(sl)) 172 return -1; 173 174 wrbuf[0] = W1_F1C_WRITE_SCRATCH; 175 wrbuf[1] = addr & 0xff; 176 wrbuf[2] = addr >> 8; 177 178 w1_write_block(sl->master, wrbuf, 3); 179 w1_write_block(sl->master, data, len); 180 181 /* Read the scratchpad and verify */ 182 if (w1_reset_select_slave(sl)) 183 return -1; 184 185 w1_write_8(sl->master, W1_F1C_READ_SCRATCH); 186 w1_read_block(sl->master, rdbuf, len + 3); 187 188 /* Compare what was read against the data written */ 189 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || 190 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) 191 return -1; 192 193 /* Copy the scratchpad to EEPROM */ 194 if (w1_reset_select_slave(sl)) 195 return -1; 196 197 wrbuf[0] = W1_F1C_COPY_SCRATCH; 198 wrbuf[3] = es; 199 200 for (i = 0; i < sizeof(wrbuf); ++i) { 201 /* 202 * issue 10ms strong pullup (or delay) on the last byte 203 * for writing the data from the scratchpad to EEPROM 204 */ 205 if (w1_strong_pullup && i == sizeof(wrbuf)-1) 206 w1_next_pullup(sl->master, tm); 207 208 w1_write_8(sl->master, wrbuf[i]); 209 } 210 211 if (!w1_strong_pullup) 212 msleep(tm); 213 214 if (w1_enable_crccheck) { 215 /* invalidate cached data */ 216 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS)); 217 } 218 219 /* Reset the bus to wake up the EEPROM (this may not be needed) */ 220 w1_reset_bus(sl->master); 221 222 return 0; 223 } 224 225 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, 226 struct bin_attribute *bin_attr, char *buf, 227 loff_t off, size_t count) 228 229 { 230 struct w1_slave *sl = kobj_to_w1_slave(kobj); 231 int addr, len, idx; 232 233 count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE); 234 if (count == 0) 235 return 0; 236 237 if (w1_enable_crccheck) { 238 /* can only write full blocks in cached mode */ 239 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { 240 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", 241 (int)off, count); 242 return -EINVAL; 243 } 244 245 /* make sure the block CRCs are valid */ 246 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { 247 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) 248 != CRC16_VALID) { 249 dev_err(&sl->dev, "bad CRC at offset %d\n", 250 (int)off); 251 return -EINVAL; 252 } 253 } 254 } 255 256 mutex_lock(&sl->master->mutex); 257 258 /* Can only write data to one page at a time */ 259 idx = 0; 260 while (idx < count) { 261 addr = off + idx; 262 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); 263 if (len > (count - idx)) 264 len = count - idx; 265 266 if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) { 267 count = -EIO; 268 goto out_up; 269 } 270 idx += len; 271 } 272 273 out_up: 274 mutex_unlock(&sl->master->mutex); 275 276 return count; 277 } 278 279 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE); 280 281 static ssize_t pio_read(struct file *filp, struct kobject *kobj, 282 struct bin_attribute *bin_attr, char *buf, loff_t off, 283 size_t count) 284 285 { 286 struct w1_slave *sl = kobj_to_w1_slave(kobj); 287 int ret; 288 289 /* check arguments */ 290 if (off != 0 || count != 1 || buf == NULL) 291 return -EINVAL; 292 293 mutex_lock(&sl->master->mutex); 294 ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf); 295 mutex_unlock(&sl->master->mutex); 296 297 return ret; 298 } 299 300 static ssize_t pio_write(struct file *filp, struct kobject *kobj, 301 struct bin_attribute *bin_attr, char *buf, loff_t off, 302 size_t count) 303 304 { 305 struct w1_slave *sl = kobj_to_w1_slave(kobj); 306 u8 wrbuf[3]; 307 u8 ack; 308 309 /* check arguments */ 310 if (off != 0 || count != 1 || buf == NULL) 311 return -EINVAL; 312 313 mutex_lock(&sl->master->mutex); 314 315 /* Write the PIO data */ 316 if (w1_reset_select_slave(sl)) { 317 mutex_unlock(&sl->master->mutex); 318 return -1; 319 } 320 321 /* set bit 7..2 to value '1' */ 322 *buf = *buf | 0xFC; 323 324 wrbuf[0] = W1_F1C_ACCESS_WRITE; 325 wrbuf[1] = *buf; 326 wrbuf[2] = ~(*buf); 327 w1_write_block(sl->master, wrbuf, 3); 328 329 w1_read_block(sl->master, &ack, sizeof(ack)); 330 331 mutex_unlock(&sl->master->mutex); 332 333 /* check for acknowledgement */ 334 if (ack != 0xAA) 335 return -EIO; 336 337 return count; 338 } 339 340 static BIN_ATTR_RW(pio, 1); 341 342 static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr, 343 char *buf) 344 { 345 return sysfs_emit(buf, "%d\n", 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 int err = kstrtobool(buf, &w1_enable_crccheck); 352 353 if (err) 354 return err; 355 356 return count; 357 } 358 359 static DEVICE_ATTR_RW(crccheck); 360 361 static struct attribute *w1_f1C_attrs[] = { 362 &dev_attr_crccheck.attr, 363 NULL, 364 }; 365 366 static struct bin_attribute *w1_f1C_bin_attrs[] = { 367 &bin_attr_eeprom, 368 &bin_attr_pio, 369 NULL, 370 }; 371 372 static const struct attribute_group w1_f1C_group = { 373 .attrs = w1_f1C_attrs, 374 .bin_attrs = w1_f1C_bin_attrs, 375 }; 376 377 static const struct attribute_group *w1_f1C_groups[] = { 378 &w1_f1C_group, 379 NULL, 380 }; 381 382 static int w1_f1C_add_slave(struct w1_slave *sl) 383 { 384 struct w1_f1C_data *data = NULL; 385 386 if (w1_enable_crccheck) { 387 data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL); 388 if (!data) 389 return -ENOMEM; 390 sl->family_data = data; 391 } 392 393 return 0; 394 } 395 396 static void w1_f1C_remove_slave(struct w1_slave *sl) 397 { 398 kfree(sl->family_data); 399 sl->family_data = NULL; 400 } 401 402 static const struct w1_family_ops w1_f1C_fops = { 403 .add_slave = w1_f1C_add_slave, 404 .remove_slave = w1_f1C_remove_slave, 405 .groups = w1_f1C_groups, 406 }; 407 408 static struct w1_family w1_family_1C = { 409 .fid = W1_FAMILY_DS28E04, 410 .fops = &w1_f1C_fops, 411 }; 412 module_w1_family(w1_family_1C); 413 414 MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>"); 415 MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO"); 416 MODULE_LICENSE("GPL"); 417 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04)); 418