Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 | // SPDX-License-Identifier: GPL-2.0-only /* * w1_ds28e17.c - w1 family 19 (DS28E17) driver * * Copyright (c) 2016 Jan Kandziora <jjj@gmx.de> */ #include <linux/crc16.h> #include <linux/delay.h> #include <linux/device.h> #include <linux/i2c.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/slab.h> #include <linux/types.h> #include <linux/uaccess.h> #define CRC16_INIT 0 #include <linux/w1.h> #define W1_FAMILY_DS28E17 0x19 /* Module setup. */ MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Jan Kandziora <jjj@gmx.de>"); MODULE_DESCRIPTION("w1 family 19 driver for DS28E17, 1-wire to I2C master bridge"); MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E17)); /* Default I2C speed to be set when a DS28E17 is detected. */ static int i2c_speed = 100; module_param_named(speed, i2c_speed, int, 0600); MODULE_PARM_DESC(speed, "Default I2C speed to be set when a DS28E17 is detected"); /* Default I2C stretch value to be set when a DS28E17 is detected. */ static char i2c_stretch = 1; module_param_named(stretch, i2c_stretch, byte, 0600); MODULE_PARM_DESC(stretch, "Default I2C stretch value to be set when a DS28E17 is detected"); /* DS28E17 device command codes. */ #define W1_F19_WRITE_DATA_WITH_STOP 0x4B #define W1_F19_WRITE_DATA_NO_STOP 0x5A #define W1_F19_WRITE_DATA_ONLY 0x69 #define W1_F19_WRITE_DATA_ONLY_WITH_STOP 0x78 #define W1_F19_READ_DATA_WITH_STOP 0x87 #define W1_F19_WRITE_READ_DATA_WITH_STOP 0x2D #define W1_F19_WRITE_CONFIGURATION 0xD2 #define W1_F19_READ_CONFIGURATION 0xE1 #define W1_F19_ENABLE_SLEEP_MODE 0x1E #define W1_F19_READ_DEVICE_REVISION 0xC4 /* DS28E17 status bits */ #define W1_F19_STATUS_CRC 0x01 #define W1_F19_STATUS_ADDRESS 0x02 #define W1_F19_STATUS_START 0x08 /* * Maximum number of I2C bytes to transfer within one CRC16 protected onewire * command. */ #define W1_F19_WRITE_DATA_LIMIT 255 /* Maximum number of I2C bytes to read with one onewire command. */ #define W1_F19_READ_DATA_LIMIT 255 /* Constants for calculating the busy sleep. */ #define W1_F19_BUSY_TIMEBASES { 90, 23, 10 } #define W1_F19_BUSY_GRATUITY 1000 /* Number of checks for the busy flag before timeout. */ #define W1_F19_BUSY_CHECKS 1000 /* Slave specific data. */ struct w1_f19_data { u8 speed; u8 stretch; struct i2c_adapter adapter; }; /* Wait a while until the busy flag clears. */ static int w1_f19_i2c_busy_wait(struct w1_slave *sl, size_t count) { const unsigned long timebases[3] = W1_F19_BUSY_TIMEBASES; struct w1_f19_data *data = sl->family_data; unsigned int checks; /* Check the busy flag first in any case.*/ if (w1_touch_bit(sl->master, 1) == 0) return 0; /* * Do a generously long sleep in the beginning, * as we have to wait at least this time for all * the I2C bytes at the given speed to be transferred. */ usleep_range(timebases[data->speed] * (data->stretch) * count, timebases[data->speed] * (data->stretch) * count + W1_F19_BUSY_GRATUITY); /* Now continusly check the busy flag sent by the DS28E17. */ checks = W1_F19_BUSY_CHECKS; while ((checks--) > 0) { /* Return success if the busy flag is cleared. */ if (w1_touch_bit(sl->master, 1) == 0) return 0; /* Wait one non-streched byte timeslot. */ udelay(timebases[data->speed]); } /* Timeout. */ dev_warn(&sl->dev, "busy timeout\n"); return -ETIMEDOUT; } /* Utility function: result. */ static size_t w1_f19_error(struct w1_slave *sl, u8 w1_buf[]) { /* Warnings. */ if (w1_buf[0] & W1_F19_STATUS_CRC) dev_warn(&sl->dev, "crc16 mismatch\n"); if (w1_buf[0] & W1_F19_STATUS_ADDRESS) dev_warn(&sl->dev, "i2c device not responding\n"); if ((w1_buf[0] & (W1_F19_STATUS_CRC | W1_F19_STATUS_ADDRESS)) == 0 && w1_buf[1] != 0) { dev_warn(&sl->dev, "i2c short write, %d bytes not acknowledged\n", w1_buf[1]); } /* Check error conditions. */ if (w1_buf[0] & W1_F19_STATUS_ADDRESS) return -ENXIO; if (w1_buf[0] & W1_F19_STATUS_START) return -EAGAIN; if (w1_buf[0] != 0 || w1_buf[1] != 0) return -EIO; /* All ok. */ return 0; } /* Utility function: write data to I2C slave, single chunk. */ static int __w1_f19_i2c_write(struct w1_slave *sl, const u8 *command, size_t command_count, const u8 *buffer, size_t count) { u16 crc; int error; u8 w1_buf[2]; /* Send command and I2C data to DS28E17. */ crc = crc16(CRC16_INIT, command, command_count); w1_write_block(sl->master, command, command_count); w1_buf[0] = count; crc = crc16(crc, w1_buf, 1); w1_write_8(sl->master, w1_buf[0]); crc = crc16(crc, buffer, count); w1_write_block(sl->master, buffer, count); w1_buf[0] = ~(crc & 0xFF); w1_buf[1] = ~((crc >> 8) & 0xFF); w1_write_block(sl->master, w1_buf, 2); /* Wait until busy flag clears (or timeout). */ if (w1_f19_i2c_busy_wait(sl, count + 1) < 0) return -ETIMEDOUT; /* Read status from DS28E17. */ w1_read_block(sl->master, w1_buf, 2); /* Check error conditions. */ error = w1_f19_error(sl, w1_buf); if (error < 0) return error; /* Return number of bytes written. */ return count; } /* Write data to I2C slave. */ static int w1_f19_i2c_write(struct w1_slave *sl, u16 i2c_address, const u8 *buffer, size_t count, bool stop) { int result; int remaining = count; const u8 *p; u8 command[2]; /* Check input. */ if (count == 0) return -EOPNOTSUPP; /* Check whether we need multiple commands. */ if (count <= W1_F19_WRITE_DATA_LIMIT) { /* * Small data amount. Data can be sent with * a single onewire command. */ /* Send all data to DS28E17. */ command[0] = (stop ? W1_F19_WRITE_DATA_WITH_STOP : W1_F19_WRITE_DATA_NO_STOP); command[1] = i2c_address << 1; result = __w1_f19_i2c_write(sl, command, 2, buffer, count); } else { /* Large data amount. Data has to be sent in multiple chunks. */ /* Send first chunk to DS28E17. */ p = buffer; command[0] = W1_F19_WRITE_DATA_NO_STOP; command[1] = i2c_address << 1; result = __w1_f19_i2c_write(sl, command, 2, p, W1_F19_WRITE_DATA_LIMIT); if (result < 0) return result; /* Resume to same DS28E17. */ if (w1_reset_resume_command(sl->master)) return -EIO; /* Next data chunk. */ p += W1_F19_WRITE_DATA_LIMIT; remaining -= W1_F19_WRITE_DATA_LIMIT; while (remaining > W1_F19_WRITE_DATA_LIMIT) { /* Send intermediate chunk to DS28E17. */ command[0] = W1_F19_WRITE_DATA_ONLY; result = __w1_f19_i2c_write(sl, command, 1, p, W1_F19_WRITE_DATA_LIMIT); if (result < 0) return result; /* Resume to same DS28E17. */ if (w1_reset_resume_command(sl->master)) return -EIO; /* Next data chunk. */ p += W1_F19_WRITE_DATA_LIMIT; remaining -= W1_F19_WRITE_DATA_LIMIT; } /* Send final chunk to DS28E17. */ command[0] = (stop ? W1_F19_WRITE_DATA_ONLY_WITH_STOP : W1_F19_WRITE_DATA_ONLY); result = __w1_f19_i2c_write(sl, command, 1, p, remaining); } return result; } /* Read data from I2C slave. */ static int w1_f19_i2c_read(struct w1_slave *sl, u16 i2c_address, u8 *buffer, size_t count) { u16 crc; int error; u8 w1_buf[5]; /* Check input. */ if (count == 0) return -EOPNOTSUPP; /* Send command to DS28E17. */ w1_buf[0] = W1_F19_READ_DATA_WITH_STOP; w1_buf[1] = i2c_address << 1 | 0x01; w1_buf[2] = count; crc = crc16(CRC16_INIT, w1_buf, 3); w1_buf[3] = ~(crc & 0xFF); w1_buf[4] = ~((crc >> 8) & 0xFF); w1_write_block(sl->master, w1_buf, 5); /* Wait until busy flag clears (or timeout). */ if (w1_f19_i2c_busy_wait(sl, count + 1) < 0) return -ETIMEDOUT; /* Read status from DS28E17. */ w1_buf[0] = w1_read_8(sl->master); w1_buf[1] = 0; /* Check error conditions. */ error = w1_f19_error(sl, w1_buf); if (error < 0) return error; /* Read received I2C data from DS28E17. */ return w1_read_block(sl->master, buffer, count); } /* Write to, then read data from I2C slave. */ static int w1_f19_i2c_write_read(struct w1_slave *sl, u16 i2c_address, const u8 *wbuffer, size_t wcount, u8 *rbuffer, size_t rcount) { u16 crc; int error; u8 w1_buf[3]; /* Check input. */ if (wcount == 0 || rcount == 0) return -EOPNOTSUPP; /* Send command and I2C data to DS28E17. */ w1_buf[0] = W1_F19_WRITE_READ_DATA_WITH_STOP; w1_buf[1] = i2c_address << 1; w1_buf[2] = wcount; crc = crc16(CRC16_INIT, w1_buf, 3); w1_write_block(sl->master, w1_buf, 3); crc = crc16(crc, wbuffer, wcount); w1_write_block(sl->master, wbuffer, wcount); w1_buf[0] = rcount; crc = crc16(crc, w1_buf, 1); w1_buf[1] = ~(crc & 0xFF); w1_buf[2] = ~((crc >> 8) & 0xFF); w1_write_block(sl->master, w1_buf, 3); /* Wait until busy flag clears (or timeout). */ if (w1_f19_i2c_busy_wait(sl, wcount + rcount + 2) < 0) return -ETIMEDOUT; /* Read status from DS28E17. */ w1_read_block(sl->master, w1_buf, 2); /* Check error conditions. */ error = w1_f19_error(sl, w1_buf); if (error < 0) return error; /* Read received I2C data from DS28E17. */ return w1_read_block(sl->master, rbuffer, rcount); } /* Do an I2C master transfer. */ static int w1_f19_i2c_master_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { struct w1_slave *sl = (struct w1_slave *) adapter->algo_data; int i = 0; int result = 0; /* Start onewire transaction. */ mutex_lock(&sl->master->bus_mutex); /* Select DS28E17. */ if (w1_reset_select_slave(sl)) { i = -EIO; goto error; } /* Loop while there are still messages to transfer. */ while (i < num) { /* * Check for special case: Small write followed * by read to same I2C device. */ if (i < (num-1) && msgs[i].addr == msgs[i+1].addr && !(msgs[i].flags & I2C_M_RD) && (msgs[i+1].flags & I2C_M_RD) && (msgs[i].len <= W1_F19_WRITE_DATA_LIMIT)) { /* * The DS28E17 has a combined transfer * for small write+read. */ result = w1_f19_i2c_write_read(sl, msgs[i].addr, msgs[i].buf, msgs[i].len, msgs[i+1].buf, msgs[i+1].len); if (result < 0) { i = result; goto error; } /* * Check if we should interpret the read data * as a length byte. The DS28E17 unfortunately * has no read without stop, so we can just do * another simple read in that case. */ if (msgs[i+1].flags & I2C_M_RECV_LEN) { result = w1_f19_i2c_read(sl, msgs[i+1].addr, &(msgs[i+1].buf[1]), msgs[i+1].buf[0]); if (result < 0) { i = result; goto error; } } /* Eat up read message, too. */ i++; } else if (msgs[i].flags & I2C_M_RD) { /* Read transfer. */ result = w1_f19_i2c_read(sl, msgs[i].addr, msgs[i].buf, msgs[i].len); if (result < 0) { i = result; goto error; } /* * Check if we should interpret the read data * as a length byte. The DS28E17 unfortunately * has no read without stop, so we can just do * another simple read in that case. */ if (msgs[i].flags & I2C_M_RECV_LEN) { result = w1_f19_i2c_read(sl, msgs[i].addr, &(msgs[i].buf[1]), msgs[i].buf[0]); if (result < 0) { i = result; goto error; } } } else { /* * Write transfer. * Stop condition only for last * transfer. */ result = w1_f19_i2c_write(sl, msgs[i].addr, msgs[i].buf, msgs[i].len, i == (num-1)); if (result < 0) { i = result; goto error; } } /* Next message. */ i++; /* Are there still messages to send/receive? */ if (i < num) { /* Yes. Resume to same DS28E17. */ if (w1_reset_resume_command(sl->master)) { i = -EIO; goto error; } } } error: /* End onewire transaction. */ mutex_unlock(&sl->master->bus_mutex); /* Return number of messages processed or error. */ return i; } /* Get I2C adapter functionality. */ static u32 w1_f19_i2c_functionality(struct i2c_adapter *adapter) { /* * Plain I2C functions only. * SMBus is emulated by the kernel's I2C layer. * No "I2C_FUNC_SMBUS_QUICK" * No "I2C_FUNC_SMBUS_READ_BLOCK_DATA" * No "I2C_FUNC_SMBUS_BLOCK_PROC_CALL" */ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_SMBUS_PEC; } /* I2C adapter quirks. */ static const struct i2c_adapter_quirks w1_f19_i2c_adapter_quirks = { .max_read_len = W1_F19_READ_DATA_LIMIT, }; /* I2C algorithm. */ static const struct i2c_algorithm w1_f19_i2c_algorithm = { .master_xfer = w1_f19_i2c_master_transfer, .functionality = w1_f19_i2c_functionality, }; /* Read I2C speed from DS28E17. */ static int w1_f19_get_i2c_speed(struct w1_slave *sl) { struct w1_f19_data *data = sl->family_data; int result = -EIO; /* Start onewire transaction. */ mutex_lock(&sl->master->bus_mutex); /* Select slave. */ if (w1_reset_select_slave(sl)) goto error; /* Read slave configuration byte. */ w1_write_8(sl->master, W1_F19_READ_CONFIGURATION); result = w1_read_8(sl->master); if (result < 0 || result > 2) { result = -EIO; goto error; } /* Update speed in slave specific data. */ data->speed = result; error: /* End onewire transaction. */ mutex_unlock(&sl->master->bus_mutex); return result; } /* Set I2C speed on DS28E17. */ static int __w1_f19_set_i2c_speed(struct w1_slave *sl, u8 speed) { struct w1_f19_data *data = sl->family_data; const int i2c_speeds[3] = { 100, 400, 900 }; u8 w1_buf[2]; /* Select slave. */ if (w1_reset_select_slave(sl)) return -EIO; w1_buf[0] = W1_F19_WRITE_CONFIGURATION; w1_buf[1] = speed; w1_write_block(sl->master, w1_buf, 2); /* Update speed in slave specific data. */ data->speed = speed; dev_info(&sl->dev, "i2c speed set to %d kBaud\n", i2c_speeds[speed]); return 0; } static int w1_f19_set_i2c_speed(struct w1_slave *sl, u8 speed) { int result; /* Start onewire transaction. */ mutex_lock(&sl->master->bus_mutex); /* Set I2C speed on DS28E17. */ result = __w1_f19_set_i2c_speed(sl, speed); /* End onewire transaction. */ mutex_unlock(&sl->master->bus_mutex); return result; } /* Sysfs attributes. */ /* I2C speed attribute for a single chip. */ static ssize_t speed_show(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_slave *sl = dev_to_w1_slave(dev); int result; /* Read current speed from slave. Updates data->speed. */ result = w1_f19_get_i2c_speed(sl); if (result < 0) return result; /* Return current speed value. */ return sprintf(buf, "%d\n", result); } static ssize_t speed_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct w1_slave *sl = dev_to_w1_slave(dev); int error; /* Valid values are: "100", "400", "900" */ if (count < 3 || count > 4 || !buf) return -EINVAL; if (count == 4 && buf[3] != '\n') return -EINVAL; if (buf[1] != '0' || buf[2] != '0') return -EINVAL; /* Set speed on slave. */ switch (buf[0]) { case '1': error = w1_f19_set_i2c_speed(sl, 0); break; case '4': error = w1_f19_set_i2c_speed(sl, 1); break; case '9': error = w1_f19_set_i2c_speed(sl, 2); break; default: return -EINVAL; } if (error < 0) return error; /* Return bytes written. */ return count; } static DEVICE_ATTR_RW(speed); /* Busy stretch attribute for a single chip. */ static ssize_t stretch_show(struct device *dev, struct device_attribute *attr, char *buf) { struct w1_slave *sl = dev_to_w1_slave(dev); struct w1_f19_data *data = sl->family_data; /* Return current stretch value. */ return sprintf(buf, "%d\n", data->stretch); } static ssize_t stretch_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct w1_slave *sl = dev_to_w1_slave(dev); struct w1_f19_data *data = sl->family_data; /* Valid values are '1' to '9' */ if (count < 1 || count > 2 || !buf) return -EINVAL; if (count == 2 && buf[1] != '\n') return -EINVAL; if (buf[0] < '1' || buf[0] > '9') return -EINVAL; /* Set busy stretch value. */ data->stretch = buf[0] & 0x0F; /* Return bytes written. */ return count; } static DEVICE_ATTR_RW(stretch); /* All attributes. */ static struct attribute *w1_f19_attrs[] = { &dev_attr_speed.attr, &dev_attr_stretch.attr, NULL, }; static const struct attribute_group w1_f19_group = { .attrs = w1_f19_attrs, }; static const struct attribute_group *w1_f19_groups[] = { &w1_f19_group, NULL, }; /* Slave add and remove functions. */ static int w1_f19_add_slave(struct w1_slave *sl) { struct w1_f19_data *data = NULL; /* Allocate memory for slave specific data. */ data = devm_kzalloc(&sl->dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; sl->family_data = data; /* Setup default I2C speed on slave. */ switch (i2c_speed) { case 100: __w1_f19_set_i2c_speed(sl, 0); break; case 400: __w1_f19_set_i2c_speed(sl, 1); break; case 900: __w1_f19_set_i2c_speed(sl, 2); break; default: /* * A i2c_speed module parameter of anything else * than 100, 400, 900 means not to touch the * speed of the DS28E17. * We assume 400kBaud, the power-on value. */ data->speed = 1; } /* * Setup default busy stretch * configuration for the DS28E17. */ data->stretch = i2c_stretch; /* Setup I2C adapter. */ data->adapter.owner = THIS_MODULE; data->adapter.algo = &w1_f19_i2c_algorithm; data->adapter.algo_data = sl; strcpy(data->adapter.name, "w1-"); strcat(data->adapter.name, sl->name); data->adapter.dev.parent = &sl->dev; data->adapter.quirks = &w1_f19_i2c_adapter_quirks; return i2c_add_adapter(&data->adapter); } static void w1_f19_remove_slave(struct w1_slave *sl) { struct w1_f19_data *family_data = sl->family_data; /* Delete I2C adapter. */ i2c_del_adapter(&family_data->adapter); /* Free slave specific data. */ devm_kfree(&sl->dev, family_data); sl->family_data = NULL; } /* Declarations within the w1 subsystem. */ static const struct w1_family_ops w1_f19_fops = { .add_slave = w1_f19_add_slave, .remove_slave = w1_f19_remove_slave, .groups = w1_f19_groups, }; static struct w1_family w1_family_19 = { .fid = W1_FAMILY_DS28E17, .fops = &w1_f19_fops, }; module_w1_family(w1_family_19); |