1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * I2C multiplexer 4 * 5 * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it> 6 * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it> 7 * 8 * This module supports the PCA954x and PCA984x series of I2C multiplexer/switch 9 * chips made by NXP Semiconductors. 10 * This includes the: 11 * PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547, 12 * PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849. 13 * 14 * It's also compatible to Maxims MAX735x I2C switch chips, which are controlled 15 * as the NXP PCA9548 and the MAX736x chips that act like the PCA9544. 16 * 17 * This includes the: 18 * MAX7356, MAX7357, MAX7358, MAX7367, MAX7368 and MAX7369 19 * 20 * These chips are all controlled via the I2C bus itself, and all have a 21 * single 8-bit register. The upstream "parent" bus fans out to two, 22 * four, or eight downstream busses or channels; which of these 23 * are selected is determined by the chip type and register contents. A 24 * mux can select only one sub-bus at a time; a switch can select any 25 * combination simultaneously. 26 * 27 * Based on: 28 * pca954x.c from Kumar Gala <galak@kernel.crashing.org> 29 * Copyright (C) 2006 30 * 31 * Based on: 32 * pca954x.c from Ken Harrenstien 33 * Copyright (C) 2004 Google, Inc. (Ken Harrenstien) 34 * 35 * Based on: 36 * i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com> 37 * and 38 * pca9540.c from Jean Delvare <jdelvare@suse.de>. 39 */ 40 41 #include <linux/device.h> 42 #include <linux/delay.h> 43 #include <linux/gpio/consumer.h> 44 #include <linux/i2c.h> 45 #include <linux/i2c-mux.h> 46 #include <linux/interrupt.h> 47 #include <linux/irq.h> 48 #include <linux/module.h> 49 #include <linux/pm.h> 50 #include <linux/property.h> 51 #include <linux/regulator/consumer.h> 52 #include <linux/slab.h> 53 #include <linux/spinlock.h> 54 #include <dt-bindings/mux/mux.h> 55 56 #define PCA954X_MAX_NCHANS 8 57 58 #define PCA954X_IRQ_OFFSET 4 59 60 enum pca_type { 61 max_7356, 62 max_7357, 63 max_7358, 64 max_7367, 65 max_7368, 66 max_7369, 67 pca_9540, 68 pca_9542, 69 pca_9543, 70 pca_9544, 71 pca_9545, 72 pca_9546, 73 pca_9547, 74 pca_9548, 75 pca_9846, 76 pca_9847, 77 pca_9848, 78 pca_9849, 79 }; 80 81 struct chip_desc { 82 u8 nchans; 83 u8 enable; /* used for muxes only */ 84 u8 has_irq; 85 enum muxtype { 86 pca954x_ismux = 0, 87 pca954x_isswi 88 } muxtype; 89 struct i2c_device_identity id; 90 }; 91 92 struct pca954x { 93 const struct chip_desc *chip; 94 95 u8 last_chan; /* last register value */ 96 /* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */ 97 s32 idle_state; 98 99 struct i2c_client *client; 100 101 struct irq_domain *irq; 102 unsigned int irq_mask; 103 raw_spinlock_t lock; 104 struct regulator *supply; 105 }; 106 107 /* Provide specs for the MAX735x, PCA954x and PCA984x types we know about */ 108 static const struct chip_desc chips[] = { 109 [max_7356] = { 110 .nchans = 8, 111 .muxtype = pca954x_isswi, 112 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 113 }, 114 [max_7357] = { 115 .nchans = 8, 116 .muxtype = pca954x_isswi, 117 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 118 /* 119 * No interrupt controller support. The interrupt 120 * provides information about stuck channels. 121 */ 122 }, 123 [max_7358] = { 124 .nchans = 8, 125 .muxtype = pca954x_isswi, 126 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 127 /* 128 * No interrupt controller support. The interrupt 129 * provides information about stuck channels. 130 */ 131 }, 132 [max_7367] = { 133 .nchans = 4, 134 .muxtype = pca954x_isswi, 135 .has_irq = 1, 136 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 137 }, 138 [max_7368] = { 139 .nchans = 4, 140 .muxtype = pca954x_isswi, 141 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 142 }, 143 [max_7369] = { 144 .nchans = 4, 145 .enable = 0x4, 146 .muxtype = pca954x_ismux, 147 .has_irq = 1, 148 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 149 }, 150 [pca_9540] = { 151 .nchans = 2, 152 .enable = 0x4, 153 .muxtype = pca954x_ismux, 154 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 155 }, 156 [pca_9542] = { 157 .nchans = 2, 158 .enable = 0x4, 159 .has_irq = 1, 160 .muxtype = pca954x_ismux, 161 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 162 }, 163 [pca_9543] = { 164 .nchans = 2, 165 .has_irq = 1, 166 .muxtype = pca954x_isswi, 167 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 168 }, 169 [pca_9544] = { 170 .nchans = 4, 171 .enable = 0x4, 172 .has_irq = 1, 173 .muxtype = pca954x_ismux, 174 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 175 }, 176 [pca_9545] = { 177 .nchans = 4, 178 .has_irq = 1, 179 .muxtype = pca954x_isswi, 180 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 181 }, 182 [pca_9546] = { 183 .nchans = 4, 184 .muxtype = pca954x_isswi, 185 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 186 }, 187 [pca_9547] = { 188 .nchans = 8, 189 .enable = 0x8, 190 .muxtype = pca954x_ismux, 191 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 192 }, 193 [pca_9548] = { 194 .nchans = 8, 195 .muxtype = pca954x_isswi, 196 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 197 }, 198 [pca_9846] = { 199 .nchans = 4, 200 .muxtype = pca954x_isswi, 201 .id = { 202 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 203 .part_id = 0x10b, 204 }, 205 }, 206 [pca_9847] = { 207 .nchans = 8, 208 .enable = 0x8, 209 .muxtype = pca954x_ismux, 210 .id = { 211 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 212 .part_id = 0x108, 213 }, 214 }, 215 [pca_9848] = { 216 .nchans = 8, 217 .muxtype = pca954x_isswi, 218 .id = { 219 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 220 .part_id = 0x10a, 221 }, 222 }, 223 [pca_9849] = { 224 .nchans = 4, 225 .enable = 0x4, 226 .muxtype = pca954x_ismux, 227 .id = { 228 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 229 .part_id = 0x109, 230 }, 231 }, 232 }; 233 234 static const struct i2c_device_id pca954x_id[] = { 235 { "max7356", max_7356 }, 236 { "max7357", max_7357 }, 237 { "max7358", max_7358 }, 238 { "max7367", max_7367 }, 239 { "max7368", max_7368 }, 240 { "max7369", max_7369 }, 241 { "pca9540", pca_9540 }, 242 { "pca9542", pca_9542 }, 243 { "pca9543", pca_9543 }, 244 { "pca9544", pca_9544 }, 245 { "pca9545", pca_9545 }, 246 { "pca9546", pca_9546 }, 247 { "pca9547", pca_9547 }, 248 { "pca9548", pca_9548 }, 249 { "pca9846", pca_9846 }, 250 { "pca9847", pca_9847 }, 251 { "pca9848", pca_9848 }, 252 { "pca9849", pca_9849 }, 253 { } 254 }; 255 MODULE_DEVICE_TABLE(i2c, pca954x_id); 256 257 static const struct of_device_id pca954x_of_match[] = { 258 { .compatible = "maxim,max7356", .data = &chips[max_7356] }, 259 { .compatible = "maxim,max7357", .data = &chips[max_7357] }, 260 { .compatible = "maxim,max7358", .data = &chips[max_7358] }, 261 { .compatible = "maxim,max7367", .data = &chips[max_7367] }, 262 { .compatible = "maxim,max7368", .data = &chips[max_7368] }, 263 { .compatible = "maxim,max7369", .data = &chips[max_7369] }, 264 { .compatible = "nxp,pca9540", .data = &chips[pca_9540] }, 265 { .compatible = "nxp,pca9542", .data = &chips[pca_9542] }, 266 { .compatible = "nxp,pca9543", .data = &chips[pca_9543] }, 267 { .compatible = "nxp,pca9544", .data = &chips[pca_9544] }, 268 { .compatible = "nxp,pca9545", .data = &chips[pca_9545] }, 269 { .compatible = "nxp,pca9546", .data = &chips[pca_9546] }, 270 { .compatible = "nxp,pca9547", .data = &chips[pca_9547] }, 271 { .compatible = "nxp,pca9548", .data = &chips[pca_9548] }, 272 { .compatible = "nxp,pca9846", .data = &chips[pca_9846] }, 273 { .compatible = "nxp,pca9847", .data = &chips[pca_9847] }, 274 { .compatible = "nxp,pca9848", .data = &chips[pca_9848] }, 275 { .compatible = "nxp,pca9849", .data = &chips[pca_9849] }, 276 {} 277 }; 278 MODULE_DEVICE_TABLE(of, pca954x_of_match); 279 280 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer() 281 for this as they will try to lock adapter a second time */ 282 static int pca954x_reg_write(struct i2c_adapter *adap, 283 struct i2c_client *client, u8 val) 284 { 285 union i2c_smbus_data dummy; 286 287 return __i2c_smbus_xfer(adap, client->addr, client->flags, 288 I2C_SMBUS_WRITE, val, 289 I2C_SMBUS_BYTE, &dummy); 290 } 291 292 static u8 pca954x_regval(struct pca954x *data, u8 chan) 293 { 294 /* We make switches look like muxes, not sure how to be smarter. */ 295 if (data->chip->muxtype == pca954x_ismux) 296 return chan | data->chip->enable; 297 else 298 return 1 << chan; 299 } 300 301 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan) 302 { 303 struct pca954x *data = i2c_mux_priv(muxc); 304 struct i2c_client *client = data->client; 305 u8 regval; 306 int ret = 0; 307 308 regval = pca954x_regval(data, chan); 309 /* Only select the channel if its different from the last channel */ 310 if (data->last_chan != regval) { 311 ret = pca954x_reg_write(muxc->parent, client, regval); 312 data->last_chan = ret < 0 ? 0 : regval; 313 } 314 315 return ret; 316 } 317 318 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan) 319 { 320 struct pca954x *data = i2c_mux_priv(muxc); 321 struct i2c_client *client = data->client; 322 s32 idle_state; 323 324 idle_state = READ_ONCE(data->idle_state); 325 if (idle_state >= 0) 326 /* Set the mux back to a predetermined channel */ 327 return pca954x_select_chan(muxc, idle_state); 328 329 if (idle_state == MUX_IDLE_DISCONNECT) { 330 /* Deselect active channel */ 331 data->last_chan = 0; 332 return pca954x_reg_write(muxc->parent, client, 333 data->last_chan); 334 } 335 336 /* otherwise leave as-is */ 337 338 return 0; 339 } 340 341 static ssize_t idle_state_show(struct device *dev, 342 struct device_attribute *attr, 343 char *buf) 344 { 345 struct i2c_client *client = to_i2c_client(dev); 346 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 347 struct pca954x *data = i2c_mux_priv(muxc); 348 349 return sprintf(buf, "%d\n", READ_ONCE(data->idle_state)); 350 } 351 352 static ssize_t idle_state_store(struct device *dev, 353 struct device_attribute *attr, 354 const char *buf, size_t count) 355 { 356 struct i2c_client *client = to_i2c_client(dev); 357 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 358 struct pca954x *data = i2c_mux_priv(muxc); 359 int val; 360 int ret; 361 362 ret = kstrtoint(buf, 0, &val); 363 if (ret < 0) 364 return ret; 365 366 if (val != MUX_IDLE_AS_IS && val != MUX_IDLE_DISCONNECT && 367 (val < 0 || val >= data->chip->nchans)) 368 return -EINVAL; 369 370 i2c_lock_bus(muxc->parent, I2C_LOCK_SEGMENT); 371 372 WRITE_ONCE(data->idle_state, val); 373 /* 374 * Set the mux into a state consistent with the new 375 * idle_state. 376 */ 377 if (data->last_chan || val != MUX_IDLE_DISCONNECT) 378 ret = pca954x_deselect_mux(muxc, 0); 379 380 i2c_unlock_bus(muxc->parent, I2C_LOCK_SEGMENT); 381 382 return ret < 0 ? ret : count; 383 } 384 385 static DEVICE_ATTR_RW(idle_state); 386 387 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id) 388 { 389 struct pca954x *data = dev_id; 390 unsigned long pending; 391 int ret, i; 392 393 ret = i2c_smbus_read_byte(data->client); 394 if (ret < 0) 395 return IRQ_NONE; 396 397 pending = (ret >> PCA954X_IRQ_OFFSET) & (BIT(data->chip->nchans) - 1); 398 for_each_set_bit(i, &pending, data->chip->nchans) 399 handle_nested_irq(irq_linear_revmap(data->irq, i)); 400 401 return IRQ_RETVAL(pending); 402 } 403 404 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type) 405 { 406 if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW) 407 return -EINVAL; 408 return 0; 409 } 410 411 static struct irq_chip pca954x_irq_chip = { 412 .name = "i2c-mux-pca954x", 413 .irq_set_type = pca954x_irq_set_type, 414 }; 415 416 static int pca954x_irq_setup(struct i2c_mux_core *muxc) 417 { 418 struct pca954x *data = i2c_mux_priv(muxc); 419 struct i2c_client *client = data->client; 420 int c, irq; 421 422 if (!data->chip->has_irq || client->irq <= 0) 423 return 0; 424 425 raw_spin_lock_init(&data->lock); 426 427 data->irq = irq_domain_add_linear(client->dev.of_node, 428 data->chip->nchans, 429 &irq_domain_simple_ops, data); 430 if (!data->irq) 431 return -ENODEV; 432 433 for (c = 0; c < data->chip->nchans; c++) { 434 irq = irq_create_mapping(data->irq, c); 435 if (!irq) { 436 dev_err(&client->dev, "failed irq create map\n"); 437 return -EINVAL; 438 } 439 irq_set_chip_data(irq, data); 440 irq_set_chip_and_handler(irq, &pca954x_irq_chip, 441 handle_simple_irq); 442 } 443 444 return 0; 445 } 446 447 static void pca954x_cleanup(struct i2c_mux_core *muxc) 448 { 449 struct pca954x *data = i2c_mux_priv(muxc); 450 int c, irq; 451 452 regulator_disable(data->supply); 453 454 if (data->irq) { 455 for (c = 0; c < data->chip->nchans; c++) { 456 irq = irq_find_mapping(data->irq, c); 457 irq_dispose_mapping(irq); 458 } 459 irq_domain_remove(data->irq); 460 } 461 i2c_mux_del_adapters(muxc); 462 } 463 464 static int pca954x_init(struct i2c_client *client, struct pca954x *data) 465 { 466 int ret; 467 468 if (data->idle_state >= 0) 469 data->last_chan = pca954x_regval(data, data->idle_state); 470 else 471 data->last_chan = 0; /* Disconnect multiplexer */ 472 473 ret = i2c_smbus_write_byte(client, data->last_chan); 474 if (ret < 0) 475 data->last_chan = 0; 476 477 return ret; 478 } 479 480 /* 481 * I2C init/probing/exit functions 482 */ 483 static int pca954x_probe(struct i2c_client *client) 484 { 485 const struct i2c_device_id *id = i2c_client_get_device_id(client); 486 struct i2c_adapter *adap = client->adapter; 487 struct device *dev = &client->dev; 488 struct gpio_desc *gpio; 489 struct i2c_mux_core *muxc; 490 struct pca954x *data; 491 int num; 492 int ret; 493 494 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE)) 495 return -ENODEV; 496 497 muxc = i2c_mux_alloc(adap, dev, PCA954X_MAX_NCHANS, sizeof(*data), 0, 498 pca954x_select_chan, pca954x_deselect_mux); 499 if (!muxc) 500 return -ENOMEM; 501 data = i2c_mux_priv(muxc); 502 503 i2c_set_clientdata(client, muxc); 504 data->client = client; 505 506 data->supply = devm_regulator_get(dev, "vdd"); 507 if (IS_ERR(data->supply)) 508 return dev_err_probe(dev, PTR_ERR(data->supply), 509 "Failed to request regulator\n"); 510 511 ret = regulator_enable(data->supply); 512 if (ret) 513 return dev_err_probe(dev, ret, 514 "Failed to enable vdd supply\n"); 515 516 /* Reset the mux if a reset GPIO is specified. */ 517 gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); 518 if (IS_ERR(gpio)) { 519 ret = PTR_ERR(gpio); 520 goto fail_cleanup; 521 } 522 if (gpio) { 523 udelay(1); 524 gpiod_set_value_cansleep(gpio, 0); 525 /* Give the chip some time to recover. */ 526 udelay(1); 527 } 528 529 data->chip = device_get_match_data(dev); 530 if (!data->chip) 531 data->chip = &chips[id->driver_data]; 532 533 if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) { 534 struct i2c_device_identity id; 535 536 ret = i2c_get_device_id(client, &id); 537 if (ret && ret != -EOPNOTSUPP) 538 goto fail_cleanup; 539 540 if (!ret && 541 (id.manufacturer_id != data->chip->id.manufacturer_id || 542 id.part_id != data->chip->id.part_id)) { 543 dev_warn(dev, "unexpected device id %03x-%03x-%x\n", 544 id.manufacturer_id, id.part_id, 545 id.die_revision); 546 ret = -ENODEV; 547 goto fail_cleanup; 548 } 549 } 550 551 data->idle_state = MUX_IDLE_AS_IS; 552 if (device_property_read_u32(dev, "idle-state", &data->idle_state)) { 553 if (device_property_read_bool(dev, "i2c-mux-idle-disconnect")) 554 data->idle_state = MUX_IDLE_DISCONNECT; 555 } 556 557 /* 558 * Write the mux register at addr to verify 559 * that the mux is in fact present. This also 560 * initializes the mux to a channel 561 * or disconnected state. 562 */ 563 ret = pca954x_init(client, data); 564 if (ret < 0) { 565 dev_warn(dev, "probe failed\n"); 566 ret = -ENODEV; 567 goto fail_cleanup; 568 } 569 570 ret = pca954x_irq_setup(muxc); 571 if (ret) 572 goto fail_cleanup; 573 574 /* Now create an adapter for each channel */ 575 for (num = 0; num < data->chip->nchans; num++) { 576 ret = i2c_mux_add_adapter(muxc, 0, num, 0); 577 if (ret) 578 goto fail_cleanup; 579 } 580 581 if (data->irq) { 582 ret = devm_request_threaded_irq(dev, data->client->irq, 583 NULL, pca954x_irq_handler, 584 IRQF_ONESHOT | IRQF_SHARED, 585 "pca954x", data); 586 if (ret) 587 goto fail_cleanup; 588 } 589 590 /* 591 * The attr probably isn't going to be needed in most cases, 592 * so don't fail completely on error. 593 */ 594 device_create_file(dev, &dev_attr_idle_state); 595 596 dev_info(dev, "registered %d multiplexed busses for I2C %s %s\n", 597 num, data->chip->muxtype == pca954x_ismux 598 ? "mux" : "switch", client->name); 599 600 return 0; 601 602 fail_cleanup: 603 pca954x_cleanup(muxc); 604 return ret; 605 } 606 607 static void pca954x_remove(struct i2c_client *client) 608 { 609 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 610 611 device_remove_file(&client->dev, &dev_attr_idle_state); 612 613 pca954x_cleanup(muxc); 614 } 615 616 static int pca954x_resume(struct device *dev) 617 { 618 struct i2c_client *client = to_i2c_client(dev); 619 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 620 struct pca954x *data = i2c_mux_priv(muxc); 621 int ret; 622 623 ret = pca954x_init(client, data); 624 if (ret < 0) 625 dev_err(&client->dev, "failed to verify mux presence\n"); 626 627 return ret; 628 } 629 630 static DEFINE_SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume); 631 632 static struct i2c_driver pca954x_driver = { 633 .driver = { 634 .name = "pca954x", 635 .pm = pm_sleep_ptr(&pca954x_pm), 636 .of_match_table = pca954x_of_match, 637 }, 638 .probe = pca954x_probe, 639 .remove = pca954x_remove, 640 .id_table = pca954x_id, 641 }; 642 643 module_i2c_driver(pca954x_driver); 644 645 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); 646 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); 647 MODULE_LICENSE("GPL v2"); 648