drivers/i2c/muxes/i2c-mux-pca954x.c

   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");