1 /* 2 * I2C multiplexer 3 * 4 * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it> 5 * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it> 6 * 7 * This module supports the PCA954x and PCA954x series of I2C multiplexer/switch 8 * chips made by NXP Semiconductors. 9 * This includes the: 10 * PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547, 11 * PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849. 12 * 13 * These chips are all controlled via the I2C bus itself, and all have a 14 * single 8-bit register. The upstream "parent" bus fans out to two, 15 * four, or eight downstream busses or channels; which of these 16 * are selected is determined by the chip type and register contents. A 17 * mux can select only one sub-bus at a time; a switch can select any 18 * combination simultaneously. 19 * 20 * Based on: 21 * pca954x.c from Kumar Gala <galak@kernel.crashing.org> 22 * Copyright (C) 2006 23 * 24 * Based on: 25 * pca954x.c from Ken Harrenstien 26 * Copyright (C) 2004 Google, Inc. (Ken Harrenstien) 27 * 28 * Based on: 29 * i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com> 30 * and 31 * pca9540.c from Jean Delvare <jdelvare@suse.de>. 32 * 33 * This file is licensed under the terms of the GNU General Public 34 * License version 2. This program is licensed "as is" without any 35 * warranty of any kind, whether express or implied. 36 */ 37 38 #include <linux/device.h> 39 #include <linux/delay.h> 40 #include <linux/gpio/consumer.h> 41 #include <linux/i2c.h> 42 #include <linux/i2c-mux.h> 43 #include <linux/interrupt.h> 44 #include <linux/irq.h> 45 #include <linux/module.h> 46 #include <linux/of.h> 47 #include <linux/of_device.h> 48 #include <linux/of_irq.h> 49 #include <linux/pm.h> 50 #include <linux/slab.h> 51 #include <linux/spinlock.h> 52 #include <dt-bindings/mux/mux.h> 53 54 #define PCA954X_MAX_NCHANS 8 55 56 #define PCA954X_IRQ_OFFSET 4 57 58 enum pca_type { 59 pca_9540, 60 pca_9542, 61 pca_9543, 62 pca_9544, 63 pca_9545, 64 pca_9546, 65 pca_9547, 66 pca_9548, 67 pca_9846, 68 pca_9847, 69 pca_9848, 70 pca_9849, 71 }; 72 73 struct chip_desc { 74 u8 nchans; 75 u8 enable; /* used for muxes only */ 76 u8 has_irq; 77 enum muxtype { 78 pca954x_ismux = 0, 79 pca954x_isswi 80 } muxtype; 81 struct i2c_device_identity id; 82 }; 83 84 struct pca954x { 85 const struct chip_desc *chip; 86 87 u8 last_chan; /* last register value */ 88 /* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */ 89 s32 idle_state; 90 91 struct i2c_client *client; 92 93 struct irq_domain *irq; 94 unsigned int irq_mask; 95 raw_spinlock_t lock; 96 }; 97 98 /* Provide specs for the PCA954x types we know about */ 99 static const struct chip_desc chips[] = { 100 [pca_9540] = { 101 .nchans = 2, 102 .enable = 0x4, 103 .muxtype = pca954x_ismux, 104 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 105 }, 106 [pca_9542] = { 107 .nchans = 2, 108 .enable = 0x4, 109 .has_irq = 1, 110 .muxtype = pca954x_ismux, 111 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 112 }, 113 [pca_9543] = { 114 .nchans = 2, 115 .has_irq = 1, 116 .muxtype = pca954x_isswi, 117 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 118 }, 119 [pca_9544] = { 120 .nchans = 4, 121 .enable = 0x4, 122 .has_irq = 1, 123 .muxtype = pca954x_ismux, 124 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 125 }, 126 [pca_9545] = { 127 .nchans = 4, 128 .has_irq = 1, 129 .muxtype = pca954x_isswi, 130 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 131 }, 132 [pca_9546] = { 133 .nchans = 4, 134 .muxtype = pca954x_isswi, 135 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 136 }, 137 [pca_9547] = { 138 .nchans = 8, 139 .enable = 0x8, 140 .muxtype = pca954x_ismux, 141 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 142 }, 143 [pca_9548] = { 144 .nchans = 8, 145 .muxtype = pca954x_isswi, 146 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE }, 147 }, 148 [pca_9846] = { 149 .nchans = 4, 150 .muxtype = pca954x_isswi, 151 .id = { 152 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 153 .part_id = 0x10b, 154 }, 155 }, 156 [pca_9847] = { 157 .nchans = 8, 158 .enable = 0x8, 159 .muxtype = pca954x_ismux, 160 .id = { 161 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 162 .part_id = 0x108, 163 }, 164 }, 165 [pca_9848] = { 166 .nchans = 8, 167 .muxtype = pca954x_isswi, 168 .id = { 169 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 170 .part_id = 0x10a, 171 }, 172 }, 173 [pca_9849] = { 174 .nchans = 4, 175 .enable = 0x4, 176 .muxtype = pca954x_ismux, 177 .id = { 178 .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS, 179 .part_id = 0x109, 180 }, 181 }, 182 }; 183 184 static const struct i2c_device_id pca954x_id[] = { 185 { "pca9540", pca_9540 }, 186 { "pca9542", pca_9542 }, 187 { "pca9543", pca_9543 }, 188 { "pca9544", pca_9544 }, 189 { "pca9545", pca_9545 }, 190 { "pca9546", pca_9546 }, 191 { "pca9547", pca_9547 }, 192 { "pca9548", pca_9548 }, 193 { "pca9846", pca_9846 }, 194 { "pca9847", pca_9847 }, 195 { "pca9848", pca_9848 }, 196 { "pca9849", pca_9849 }, 197 { } 198 }; 199 MODULE_DEVICE_TABLE(i2c, pca954x_id); 200 201 #ifdef CONFIG_OF 202 static const struct of_device_id pca954x_of_match[] = { 203 { .compatible = "nxp,pca9540", .data = &chips[pca_9540] }, 204 { .compatible = "nxp,pca9542", .data = &chips[pca_9542] }, 205 { .compatible = "nxp,pca9543", .data = &chips[pca_9543] }, 206 { .compatible = "nxp,pca9544", .data = &chips[pca_9544] }, 207 { .compatible = "nxp,pca9545", .data = &chips[pca_9545] }, 208 { .compatible = "nxp,pca9546", .data = &chips[pca_9546] }, 209 { .compatible = "nxp,pca9547", .data = &chips[pca_9547] }, 210 { .compatible = "nxp,pca9548", .data = &chips[pca_9548] }, 211 { .compatible = "nxp,pca9846", .data = &chips[pca_9846] }, 212 { .compatible = "nxp,pca9847", .data = &chips[pca_9847] }, 213 { .compatible = "nxp,pca9848", .data = &chips[pca_9848] }, 214 { .compatible = "nxp,pca9849", .data = &chips[pca_9849] }, 215 {} 216 }; 217 MODULE_DEVICE_TABLE(of, pca954x_of_match); 218 #endif 219 220 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer() 221 for this as they will try to lock adapter a second time */ 222 static int pca954x_reg_write(struct i2c_adapter *adap, 223 struct i2c_client *client, u8 val) 224 { 225 union i2c_smbus_data dummy; 226 227 return __i2c_smbus_xfer(adap, client->addr, client->flags, 228 I2C_SMBUS_WRITE, val, 229 I2C_SMBUS_BYTE, &dummy); 230 } 231 232 static u8 pca954x_regval(struct pca954x *data, u8 chan) 233 { 234 /* We make switches look like muxes, not sure how to be smarter. */ 235 if (data->chip->muxtype == pca954x_ismux) 236 return chan | data->chip->enable; 237 else 238 return 1 << chan; 239 } 240 241 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan) 242 { 243 struct pca954x *data = i2c_mux_priv(muxc); 244 struct i2c_client *client = data->client; 245 u8 regval; 246 int ret = 0; 247 248 regval = pca954x_regval(data, chan); 249 /* Only select the channel if its different from the last channel */ 250 if (data->last_chan != regval) { 251 ret = pca954x_reg_write(muxc->parent, client, regval); 252 data->last_chan = ret < 0 ? 0 : regval; 253 } 254 255 return ret; 256 } 257 258 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan) 259 { 260 struct pca954x *data = i2c_mux_priv(muxc); 261 struct i2c_client *client = data->client; 262 s32 idle_state; 263 264 idle_state = READ_ONCE(data->idle_state); 265 if (idle_state >= 0) 266 /* Set the mux back to a predetermined channel */ 267 return pca954x_select_chan(muxc, idle_state); 268 269 if (idle_state == MUX_IDLE_DISCONNECT) { 270 /* Deselect active channel */ 271 data->last_chan = 0; 272 return pca954x_reg_write(muxc->parent, client, 273 data->last_chan); 274 } 275 276 /* otherwise leave as-is */ 277 278 return 0; 279 } 280 281 static ssize_t idle_state_show(struct device *dev, 282 struct device_attribute *attr, 283 char *buf) 284 { 285 struct i2c_client *client = to_i2c_client(dev); 286 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 287 struct pca954x *data = i2c_mux_priv(muxc); 288 289 return sprintf(buf, "%d\n", READ_ONCE(data->idle_state)); 290 } 291 292 static ssize_t idle_state_store(struct device *dev, 293 struct device_attribute *attr, 294 const char *buf, size_t count) 295 { 296 struct i2c_client *client = to_i2c_client(dev); 297 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 298 struct pca954x *data = i2c_mux_priv(muxc); 299 int val; 300 int ret; 301 302 ret = kstrtoint(buf, 0, &val); 303 if (ret < 0) 304 return ret; 305 306 if (val != MUX_IDLE_AS_IS && val != MUX_IDLE_DISCONNECT && 307 (val < 0 || val >= data->chip->nchans)) 308 return -EINVAL; 309 310 i2c_lock_bus(muxc->parent, I2C_LOCK_SEGMENT); 311 312 WRITE_ONCE(data->idle_state, val); 313 /* 314 * Set the mux into a state consistent with the new 315 * idle_state. 316 */ 317 if (data->last_chan || val != MUX_IDLE_DISCONNECT) 318 ret = pca954x_deselect_mux(muxc, 0); 319 320 i2c_unlock_bus(muxc->parent, I2C_LOCK_SEGMENT); 321 322 return ret < 0 ? ret : count; 323 } 324 325 static DEVICE_ATTR_RW(idle_state); 326 327 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id) 328 { 329 struct pca954x *data = dev_id; 330 unsigned int child_irq; 331 int ret, i, handled = 0; 332 333 ret = i2c_smbus_read_byte(data->client); 334 if (ret < 0) 335 return IRQ_NONE; 336 337 for (i = 0; i < data->chip->nchans; i++) { 338 if (ret & BIT(PCA954X_IRQ_OFFSET + i)) { 339 child_irq = irq_linear_revmap(data->irq, i); 340 handle_nested_irq(child_irq); 341 handled++; 342 } 343 } 344 return handled ? IRQ_HANDLED : IRQ_NONE; 345 } 346 347 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type) 348 { 349 if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW) 350 return -EINVAL; 351 return 0; 352 } 353 354 static struct irq_chip pca954x_irq_chip = { 355 .name = "i2c-mux-pca954x", 356 .irq_set_type = pca954x_irq_set_type, 357 }; 358 359 static int pca954x_irq_setup(struct i2c_mux_core *muxc) 360 { 361 struct pca954x *data = i2c_mux_priv(muxc); 362 struct i2c_client *client = data->client; 363 int c, irq; 364 365 if (!data->chip->has_irq || client->irq <= 0) 366 return 0; 367 368 raw_spin_lock_init(&data->lock); 369 370 data->irq = irq_domain_add_linear(client->dev.of_node, 371 data->chip->nchans, 372 &irq_domain_simple_ops, data); 373 if (!data->irq) 374 return -ENODEV; 375 376 for (c = 0; c < data->chip->nchans; c++) { 377 irq = irq_create_mapping(data->irq, c); 378 if (!irq) { 379 dev_err(&client->dev, "failed irq create map\n"); 380 return -EINVAL; 381 } 382 irq_set_chip_data(irq, data); 383 irq_set_chip_and_handler(irq, &pca954x_irq_chip, 384 handle_simple_irq); 385 } 386 387 return 0; 388 } 389 390 static void pca954x_cleanup(struct i2c_mux_core *muxc) 391 { 392 struct pca954x *data = i2c_mux_priv(muxc); 393 struct i2c_client *client = data->client; 394 int c, irq; 395 396 device_remove_file(&client->dev, &dev_attr_idle_state); 397 398 if (data->irq) { 399 for (c = 0; c < data->chip->nchans; c++) { 400 irq = irq_find_mapping(data->irq, c); 401 irq_dispose_mapping(irq); 402 } 403 irq_domain_remove(data->irq); 404 } 405 i2c_mux_del_adapters(muxc); 406 } 407 408 static int pca954x_init(struct i2c_client *client, struct pca954x *data) 409 { 410 int ret; 411 412 if (data->idle_state >= 0) 413 data->last_chan = pca954x_regval(data, data->idle_state); 414 else 415 data->last_chan = 0; /* Disconnect multiplexer */ 416 417 ret = i2c_smbus_write_byte(client, data->last_chan); 418 if (ret < 0) 419 data->last_chan = 0; 420 421 return ret; 422 } 423 424 /* 425 * I2C init/probing/exit functions 426 */ 427 static int pca954x_probe(struct i2c_client *client, 428 const struct i2c_device_id *id) 429 { 430 struct i2c_adapter *adap = client->adapter; 431 struct device *dev = &client->dev; 432 struct device_node *np = dev->of_node; 433 struct gpio_desc *gpio; 434 struct i2c_mux_core *muxc; 435 struct pca954x *data; 436 int num; 437 int ret; 438 439 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE)) 440 return -ENODEV; 441 442 muxc = i2c_mux_alloc(adap, dev, PCA954X_MAX_NCHANS, sizeof(*data), 0, 443 pca954x_select_chan, pca954x_deselect_mux); 444 if (!muxc) 445 return -ENOMEM; 446 data = i2c_mux_priv(muxc); 447 448 i2c_set_clientdata(client, muxc); 449 data->client = client; 450 451 /* Reset the mux if a reset GPIO is specified. */ 452 gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); 453 if (IS_ERR(gpio)) 454 return PTR_ERR(gpio); 455 if (gpio) { 456 udelay(1); 457 gpiod_set_value_cansleep(gpio, 0); 458 /* Give the chip some time to recover. */ 459 udelay(1); 460 } 461 462 data->chip = of_device_get_match_data(dev); 463 if (!data->chip) 464 data->chip = &chips[id->driver_data]; 465 466 if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) { 467 struct i2c_device_identity id; 468 469 ret = i2c_get_device_id(client, &id); 470 if (ret && ret != -EOPNOTSUPP) 471 return ret; 472 473 if (!ret && 474 (id.manufacturer_id != data->chip->id.manufacturer_id || 475 id.part_id != data->chip->id.part_id)) { 476 dev_warn(dev, "unexpected device id %03x-%03x-%x\n", 477 id.manufacturer_id, id.part_id, 478 id.die_revision); 479 return -ENODEV; 480 } 481 } 482 483 data->idle_state = MUX_IDLE_AS_IS; 484 if (of_property_read_u32(np, "idle-state", &data->idle_state)) { 485 if (np && of_property_read_bool(np, "i2c-mux-idle-disconnect")) 486 data->idle_state = MUX_IDLE_DISCONNECT; 487 } 488 489 /* 490 * Write the mux register at addr to verify 491 * that the mux is in fact present. This also 492 * initializes the mux to a channel 493 * or disconnected state. 494 */ 495 ret = pca954x_init(client, data); 496 if (ret < 0) { 497 dev_warn(dev, "probe failed\n"); 498 return -ENODEV; 499 } 500 501 ret = pca954x_irq_setup(muxc); 502 if (ret) 503 goto fail_cleanup; 504 505 /* Now create an adapter for each channel */ 506 for (num = 0; num < data->chip->nchans; num++) { 507 ret = i2c_mux_add_adapter(muxc, 0, num, 0); 508 if (ret) 509 goto fail_cleanup; 510 } 511 512 if (data->irq) { 513 ret = devm_request_threaded_irq(dev, data->client->irq, 514 NULL, pca954x_irq_handler, 515 IRQF_ONESHOT | IRQF_SHARED, 516 "pca954x", data); 517 if (ret) 518 goto fail_cleanup; 519 } 520 521 /* 522 * The attr probably isn't going to be needed in most cases, 523 * so don't fail completely on error. 524 */ 525 device_create_file(dev, &dev_attr_idle_state); 526 527 dev_info(dev, "registered %d multiplexed busses for I2C %s %s\n", 528 num, data->chip->muxtype == pca954x_ismux 529 ? "mux" : "switch", client->name); 530 531 return 0; 532 533 fail_cleanup: 534 pca954x_cleanup(muxc); 535 return ret; 536 } 537 538 static int pca954x_remove(struct i2c_client *client) 539 { 540 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 541 542 pca954x_cleanup(muxc); 543 return 0; 544 } 545 546 #ifdef CONFIG_PM_SLEEP 547 static int pca954x_resume(struct device *dev) 548 { 549 struct i2c_client *client = to_i2c_client(dev); 550 struct i2c_mux_core *muxc = i2c_get_clientdata(client); 551 struct pca954x *data = i2c_mux_priv(muxc); 552 int ret; 553 554 ret = pca954x_init(client, data); 555 if (ret < 0) 556 dev_err(&client->dev, "failed to verify mux presence\n"); 557 558 return ret; 559 } 560 #endif 561 562 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume); 563 564 static struct i2c_driver pca954x_driver = { 565 .driver = { 566 .name = "pca954x", 567 .pm = &pca954x_pm, 568 .of_match_table = of_match_ptr(pca954x_of_match), 569 }, 570 .probe = pca954x_probe, 571 .remove = pca954x_remove, 572 .id_table = pca954x_id, 573 }; 574 575 module_i2c_driver(pca954x_driver); 576 577 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); 578 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); 579 MODULE_LICENSE("GPL v2"); 580