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