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/reset.h>
  53 #include <linux/slab.h>
  54 #include <linux/spinlock.h>
  55 #include <dt-bindings/mux/mux.h>
  56
  57 #define PCA954X_MAX_NCHANS 8
  58
  59 #define PCA954X_IRQ_OFFSET 4
  60
  61 /*
  62  * MAX7357's configuration register is writeable after POR, but
  63  * can be locked by setting the basic mode bit. MAX7358 configuration
  64  * register is locked by default and needs to be unlocked first.
  65  * The configuration register holds the following settings:
  66  */
  67 #define MAX7357_CONF_INT_ENABLE                 BIT(0)
  68 #define MAX7357_CONF_FLUSH_OUT                  BIT(1)
  69 #define MAX7357_CONF_RELEASE_INT                BIT(2)
  70 #define MAX7357_CONF_DISCON_SINGLE_CHAN         BIT(4)
  71 #define MAX7357_CONF_PRECONNECT_TEST            BIT(7)
  72
  73 #define MAX7357_POR_DEFAULT_CONF                MAX7357_CONF_INT_ENABLE
  74
  75 enum pca_type {
  76         max_7356,
  77         max_7357,
  78         max_7358,
  79         max_7367,
  80         max_7368,
  81         max_7369,
  82         pca_9540,
  83         pca_9542,
  84         pca_9543,
  85         pca_9544,
  86         pca_9545,
  87         pca_9546,
  88         pca_9547,
  89         pca_9548,
  90         pca_9846,
  91         pca_9847,
  92         pca_9848,
  93         pca_9849,
  94 };
  95
  96 struct chip_desc {
  97         u8 nchans;
  98         u8 enable;      /* used for muxes only */
  99         u8 has_irq;
 100         enum muxtype {
 101                 pca954x_ismux = 0,
 102                 pca954x_isswi
 103         } muxtype;
 104         struct i2c_device_identity id;
 105 };
 106
 107 struct pca954x {
 108         const struct chip_desc *chip;
 109
 110         u8 last_chan;           /* last register value */
 111         /* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */
 112         s32 idle_state;
 113
 114         struct i2c_client *client;
 115
 116         struct irq_domain *irq;
 117         unsigned int irq_mask;
 118         raw_spinlock_t lock;
 119         struct regulator *supply;
 120
 121         struct gpio_desc *reset_gpio;
 122         struct reset_control *reset_cont;
 123 };
 124
 125 /* Provide specs for the MAX735x, PCA954x and PCA984x types we know about */
 126 static const struct chip_desc chips[] = {
 127         [max_7356] = {
 128                 .nchans = 8,
 129                 .muxtype = pca954x_isswi,
 130                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 131         },
 132         [max_7357] = {
 133                 .nchans = 8,
 134                 .muxtype = pca954x_isswi,
 135                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 136                 /*
 137                  * No interrupt controller support. The interrupt
 138                  * provides information about stuck channels.
 139                  */
 140         },
 141         [max_7358] = {
 142                 .nchans = 8,
 143                 .muxtype = pca954x_isswi,
 144                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 145                 /*
 146                  * No interrupt controller support. The interrupt
 147                  * provides information about stuck channels.
 148                  */
 149         },
 150         [max_7367] = {
 151                 .nchans = 4,
 152                 .muxtype = pca954x_isswi,
 153                 .has_irq = 1,
 154                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 155         },
 156         [max_7368] = {
 157                 .nchans = 4,
 158                 .muxtype = pca954x_isswi,
 159                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 160         },
 161         [max_7369] = {
 162                 .nchans = 4,
 163                 .enable = 0x4,
 164                 .muxtype = pca954x_ismux,
 165                 .has_irq = 1,
 166                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 167         },
 168         [pca_9540] = {
 169                 .nchans = 2,
 170                 .enable = 0x4,
 171                 .muxtype = pca954x_ismux,
 172                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 173         },
 174         [pca_9542] = {
 175                 .nchans = 2,
 176                 .enable = 0x4,
 177                 .has_irq = 1,
 178                 .muxtype = pca954x_ismux,
 179                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 180         },
 181         [pca_9543] = {
 182                 .nchans = 2,
 183                 .has_irq = 1,
 184                 .muxtype = pca954x_isswi,
 185                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 186         },
 187         [pca_9544] = {
 188                 .nchans = 4,
 189                 .enable = 0x4,
 190                 .has_irq = 1,
 191                 .muxtype = pca954x_ismux,
 192                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 193         },
 194         [pca_9545] = {
 195                 .nchans = 4,
 196                 .has_irq = 1,
 197                 .muxtype = pca954x_isswi,
 198                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 199         },
 200         [pca_9546] = {
 201                 .nchans = 4,
 202                 .muxtype = pca954x_isswi,
 203                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 204         },
 205         [pca_9547] = {
 206                 .nchans = 8,
 207                 .enable = 0x8,
 208                 .muxtype = pca954x_ismux,
 209                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 210         },
 211         [pca_9548] = {
 212                 .nchans = 8,
 213                 .muxtype = pca954x_isswi,
 214                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 215         },
 216         [pca_9846] = {
 217                 .nchans = 4,
 218                 .muxtype = pca954x_isswi,
 219                 .id = {
 220                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 221                         .part_id = 0x10b,
 222                 },
 223         },
 224         [pca_9847] = {
 225                 .nchans = 8,
 226                 .enable = 0x8,
 227                 .muxtype = pca954x_ismux,
 228                 .id = {
 229                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 230                         .part_id = 0x108,
 231                 },
 232         },
 233         [pca_9848] = {
 234                 .nchans = 8,
 235                 .muxtype = pca954x_isswi,
 236                 .id = {
 237                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 238                         .part_id = 0x10a,
 239                 },
 240         },
 241         [pca_9849] = {
 242                 .nchans = 4,
 243                 .enable = 0x4,
 244                 .muxtype = pca954x_ismux,
 245                 .id = {
 246                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 247                         .part_id = 0x109,
 248                 },
 249         },
 250 };
 251
 252 static const struct i2c_device_id pca954x_id[] = {
 253         { "max7356", max_7356 },
 254         { "max7357", max_7357 },
 255         { "max7358", max_7358 },
 256         { "max7367", max_7367 },
 257         { "max7368", max_7368 },
 258         { "max7369", max_7369 },
 259         { "pca9540", pca_9540 },
 260         { "pca9542", pca_9542 },
 261         { "pca9543", pca_9543 },
 262         { "pca9544", pca_9544 },
 263         { "pca9545", pca_9545 },
 264         { "pca9546", pca_9546 },
 265         { "pca9547", pca_9547 },
 266         { "pca9548", pca_9548 },
 267         { "pca9846", pca_9846 },
 268         { "pca9847", pca_9847 },
 269         { "pca9848", pca_9848 },
 270         { "pca9849", pca_9849 },
 271         { }
 272 };
 273 MODULE_DEVICE_TABLE(i2c, pca954x_id);
 274
 275 static const struct of_device_id pca954x_of_match[] = {
 276         { .compatible = "maxim,max7356", .data = &chips[max_7356] },
 277         { .compatible = "maxim,max7357", .data = &chips[max_7357] },
 278         { .compatible = "maxim,max7358", .data = &chips[max_7358] },
 279         { .compatible = "maxim,max7367", .data = &chips[max_7367] },
 280         { .compatible = "maxim,max7368", .data = &chips[max_7368] },
 281         { .compatible = "maxim,max7369", .data = &chips[max_7369] },
 282         { .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
 283         { .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
 284         { .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
 285         { .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
 286         { .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
 287         { .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
 288         { .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
 289         { .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
 290         { .compatible = "nxp,pca9846", .data = &chips[pca_9846] },
 291         { .compatible = "nxp,pca9847", .data = &chips[pca_9847] },
 292         { .compatible = "nxp,pca9848", .data = &chips[pca_9848] },
 293         { .compatible = "nxp,pca9849", .data = &chips[pca_9849] },
 294         {}
 295 };
 296 MODULE_DEVICE_TABLE(of, pca954x_of_match);
 297
 298 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
 299    for this as they will try to lock adapter a second time */
 300 static int pca954x_reg_write(struct i2c_adapter *adap,
 301                              struct i2c_client *client, u8 val)
 302 {
 303         union i2c_smbus_data dummy;
 304
 305         return __i2c_smbus_xfer(adap, client->addr, client->flags,
 306                                 I2C_SMBUS_WRITE, val,
 307                                 I2C_SMBUS_BYTE, &dummy);
 308 }
 309
 310 static u8 pca954x_regval(struct pca954x *data, u8 chan)
 311 {
 312         /* We make switches look like muxes, not sure how to be smarter. */
 313         if (data->chip->muxtype == pca954x_ismux)
 314                 return chan | data->chip->enable;
 315         else
 316                 return 1 << chan;
 317 }
 318
 319 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
 320 {
 321         struct pca954x *data = i2c_mux_priv(muxc);
 322         struct i2c_client *client = data->client;
 323         u8 regval;
 324         int ret = 0;
 325
 326         regval = pca954x_regval(data, chan);
 327         /* Only select the channel if its different from the last channel */
 328         if (data->last_chan != regval) {
 329                 ret = pca954x_reg_write(muxc->parent, client, regval);
 330                 data->last_chan = ret < 0 ? 0 : regval;
 331         }
 332
 333         return ret;
 334 }
 335
 336 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
 337 {
 338         struct pca954x *data = i2c_mux_priv(muxc);
 339         struct i2c_client *client = data->client;
 340         s32 idle_state;
 341
 342         idle_state = READ_ONCE(data->idle_state);
 343         if (idle_state >= 0)
 344                 /* Set the mux back to a predetermined channel */
 345                 return pca954x_select_chan(muxc, idle_state);
 346
 347         if (idle_state == MUX_IDLE_DISCONNECT) {
 348                 /* Deselect active channel */
 349                 data->last_chan = 0;
 350                 return pca954x_reg_write(muxc->parent, client,
 351                                          data->last_chan);
 352         }
 353
 354         /* otherwise leave as-is */
 355
 356         return 0;
 357 }
 358
 359 static ssize_t idle_state_show(struct device *dev,
 360                                     struct device_attribute *attr,
 361                                     char *buf)
 362 {
 363         struct i2c_client *client = to_i2c_client(dev);
 364         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 365         struct pca954x *data = i2c_mux_priv(muxc);
 366
 367         return sprintf(buf, "%d\n", READ_ONCE(data->idle_state));
 368 }
 369
 370 static ssize_t idle_state_store(struct device *dev,
 371                                 struct device_attribute *attr,
 372                                 const char *buf, size_t count)
 373 {
 374         struct i2c_client *client = to_i2c_client(dev);
 375         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 376         struct pca954x *data = i2c_mux_priv(muxc);
 377         int val;
 378         int ret;
 379
 380         ret = kstrtoint(buf, 0, &val);
 381         if (ret < 0)
 382                 return ret;
 383
 384         if (val != MUX_IDLE_AS_IS && val != MUX_IDLE_DISCONNECT &&
 385             (val < 0 || val >= data->chip->nchans))
 386                 return -EINVAL;
 387
 388         i2c_lock_bus(muxc->parent, I2C_LOCK_SEGMENT);
 389
 390         WRITE_ONCE(data->idle_state, val);
 391         /*
 392          * Set the mux into a state consistent with the new
 393          * idle_state.
 394          */
 395         if (data->last_chan || val != MUX_IDLE_DISCONNECT)
 396                 ret = pca954x_deselect_mux(muxc, 0);
 397
 398         i2c_unlock_bus(muxc->parent, I2C_LOCK_SEGMENT);
 399
 400         return ret < 0 ? ret : count;
 401 }
 402
 403 static DEVICE_ATTR_RW(idle_state);
 404
 405 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
 406 {
 407         struct pca954x *data = dev_id;
 408         unsigned long pending;
 409         int ret, i;
 410
 411         ret = i2c_smbus_read_byte(data->client);
 412         if (ret < 0)
 413                 return IRQ_NONE;
 414
 415         pending = (ret >> PCA954X_IRQ_OFFSET) & (BIT(data->chip->nchans) - 1);
 416         for_each_set_bit(i, &pending, data->chip->nchans)
 417                 handle_nested_irq(irq_linear_revmap(data->irq, i));
 418
 419         return IRQ_RETVAL(pending);
 420 }
 421
 422 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
 423 {
 424         if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
 425                 return -EINVAL;
 426         return 0;
 427 }
 428
 429 static struct irq_chip pca954x_irq_chip = {
 430         .name = "i2c-mux-pca954x",
 431         .irq_set_type = pca954x_irq_set_type,
 432 };
 433
 434 static int pca954x_irq_setup(struct i2c_mux_core *muxc)
 435 {
 436         struct pca954x *data = i2c_mux_priv(muxc);
 437         struct i2c_client *client = data->client;
 438         int c, irq;
 439
 440         if (!data->chip->has_irq || client->irq <= 0)
 441                 return 0;
 442
 443         raw_spin_lock_init(&data->lock);
 444
 445         data->irq = irq_domain_add_linear(client->dev.of_node,
 446                                           data->chip->nchans,
 447                                           &irq_domain_simple_ops, data);
 448         if (!data->irq)
 449                 return -ENODEV;
 450
 451         for (c = 0; c < data->chip->nchans; c++) {
 452                 irq = irq_create_mapping(data->irq, c);
 453                 if (!irq) {
 454                         dev_err(&client->dev, "failed irq create map\n");
 455                         return -EINVAL;
 456                 }
 457                 irq_set_chip_data(irq, data);
 458                 irq_set_chip_and_handler(irq, &pca954x_irq_chip,
 459                         handle_simple_irq);
 460         }
 461
 462         return 0;
 463 }
 464
 465 static void pca954x_cleanup(struct i2c_mux_core *muxc)
 466 {
 467         struct pca954x *data = i2c_mux_priv(muxc);
 468         int c, irq;
 469
 470         regulator_disable(data->supply);
 471
 472         if (data->irq) {
 473                 for (c = 0; c < data->chip->nchans; c++) {
 474                         irq = irq_find_mapping(data->irq, c);
 475                         irq_dispose_mapping(irq);
 476                 }
 477                 irq_domain_remove(data->irq);
 478         }
 479         i2c_mux_del_adapters(muxc);
 480 }
 481
 482 static int pca954x_init(struct i2c_client *client, struct pca954x *data)
 483 {
 484         int ret;
 485
 486         if (data->idle_state >= 0)
 487                 data->last_chan = pca954x_regval(data, data->idle_state);
 488         else
 489                 data->last_chan = 0; /* Disconnect multiplexer */
 490
 491         if (device_is_compatible(&client->dev, "maxim,max7357")) {
 492                 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
 493                         u8 conf = MAX7357_POR_DEFAULT_CONF;
 494                         /*
 495                          * The interrupt signal is shared with the reset pin. Release the
 496                          * interrupt after 1.6 seconds to allow using the pin as reset.
 497                          */
 498                         conf |= MAX7357_CONF_RELEASE_INT;
 499
 500                         if (device_property_read_bool(&client->dev, "maxim,isolate-stuck-channel"))
 501                                 conf |= MAX7357_CONF_DISCON_SINGLE_CHAN;
 502                         if (device_property_read_bool(&client->dev,
 503                                                       "maxim,send-flush-out-sequence"))
 504                                 conf |= MAX7357_CONF_FLUSH_OUT;
 505                         if (device_property_read_bool(&client->dev,
 506                                                       "maxim,preconnection-wiggle-test-enable"))
 507                                 conf |= MAX7357_CONF_PRECONNECT_TEST;
 508
 509                         ret = i2c_smbus_write_byte_data(client, data->last_chan, conf);
 510                 } else {
 511                         dev_warn(&client->dev, "Write byte data not supported."
 512                                  "Cannot enable enhanced mode features\n");
 513                         ret = i2c_smbus_write_byte(client, data->last_chan);
 514                 }
 515         } else {
 516                 ret = i2c_smbus_write_byte(client, data->last_chan);
 517         }
 518
 519         if (ret < 0)
 520                 data->last_chan = 0;
 521
 522         return ret;
 523 }
 524
 525 static int pca954x_get_reset(struct device *dev, struct pca954x *data)
 526 {
 527         data->reset_cont = devm_reset_control_get_optional_shared(dev, NULL);
 528         if (IS_ERR(data->reset_cont))
 529                 return dev_err_probe(dev, PTR_ERR(data->reset_cont),
 530                                      "Failed to get reset\n");
 531         else if (data->reset_cont)
 532                 return 0;
 533
 534         /*
 535          * fallback to legacy reset-gpios
 536          */
 537         data->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 538         if (IS_ERR(data->reset_gpio)) {
 539                 return dev_err_probe(dev, PTR_ERR(data->reset_gpio),
 540                                      "Failed to get reset gpio");
 541         }
 542
 543         return 0;
 544 }
 545
 546 static void pca954x_reset_deassert(struct pca954x *data)
 547 {
 548         if (data->reset_cont)
 549                 reset_control_deassert(data->reset_cont);
 550         else
 551                 gpiod_set_value_cansleep(data->reset_gpio, 0);
 552 }
 553
 554 /*
 555  * I2C init/probing/exit functions
 556  */
 557 static int pca954x_probe(struct i2c_client *client)
 558 {
 559         const struct i2c_device_id *id = i2c_client_get_device_id(client);
 560         struct i2c_adapter *adap = client->adapter;
 561         struct device *dev = &client->dev;
 562         struct i2c_mux_core *muxc;
 563         struct pca954x *data;
 564         int num;
 565         int ret;
 566
 567         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
 568                 return -ENODEV;
 569
 570         muxc = i2c_mux_alloc(adap, dev, PCA954X_MAX_NCHANS, sizeof(*data), 0,
 571                              pca954x_select_chan, pca954x_deselect_mux);
 572         if (!muxc)
 573                 return -ENOMEM;
 574         data = i2c_mux_priv(muxc);
 575
 576         i2c_set_clientdata(client, muxc);
 577         data->client = client;
 578
 579         data->supply = devm_regulator_get(dev, "vdd");
 580         if (IS_ERR(data->supply))
 581                 return dev_err_probe(dev, PTR_ERR(data->supply),
 582                                 "Failed to request regulator\n");
 583
 584         ret = regulator_enable(data->supply);
 585         if (ret)
 586                 return dev_err_probe(dev, ret,
 587                                      "Failed to enable vdd supply\n");
 588
 589         ret = pca954x_get_reset(dev, data);
 590         if (ret)
 591                 goto fail_cleanup;
 592
 593         if (data->reset_cont || data->reset_gpio) {
 594                 udelay(1);
 595                 pca954x_reset_deassert(data);
 596                 /* Give the chip some time to recover. */
 597                 udelay(1);
 598         }
 599
 600         data->chip = device_get_match_data(dev);
 601         if (!data->chip)
 602                 data->chip = &chips[id->driver_data];
 603
 604         if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {
 605                 struct i2c_device_identity id;
 606
 607                 ret = i2c_get_device_id(client, &id);
 608                 if (ret && ret != -EOPNOTSUPP)
 609                         goto fail_cleanup;
 610
 611                 if (!ret &&
 612                     (id.manufacturer_id != data->chip->id.manufacturer_id ||
 613                      id.part_id != data->chip->id.part_id)) {
 614                         dev_warn(dev, "unexpected device id %03x-%03x-%x\n",
 615                                  id.manufacturer_id, id.part_id,
 616                                  id.die_revision);
 617                         ret = -ENODEV;
 618                         goto fail_cleanup;
 619                 }
 620         }
 621
 622         data->idle_state = MUX_IDLE_AS_IS;
 623         if (device_property_read_u32(dev, "idle-state", &data->idle_state)) {
 624                 if (device_property_read_bool(dev, "i2c-mux-idle-disconnect"))
 625                         data->idle_state = MUX_IDLE_DISCONNECT;
 626         }
 627
 628         /*
 629          * Write the mux register at addr to verify
 630          * that the mux is in fact present. This also
 631          * initializes the mux to a channel
 632          * or disconnected state.
 633          */
 634         ret = pca954x_init(client, data);
 635         if (ret < 0) {
 636                 dev_warn(dev, "probe failed\n");
 637                 ret = -ENODEV;
 638                 goto fail_cleanup;
 639         }
 640
 641         ret = pca954x_irq_setup(muxc);
 642         if (ret)
 643                 goto fail_cleanup;
 644
 645         /* Now create an adapter for each channel */
 646         for (num = 0; num < data->chip->nchans; num++) {
 647                 ret = i2c_mux_add_adapter(muxc, 0, num);
 648                 if (ret)
 649                         goto fail_cleanup;
 650         }
 651
 652         if (data->irq) {
 653                 ret = devm_request_threaded_irq(dev, data->client->irq,
 654                                                 NULL, pca954x_irq_handler,
 655                                                 IRQF_ONESHOT | IRQF_SHARED,
 656                                                 "pca954x", data);
 657                 if (ret)
 658                         goto fail_cleanup;
 659         }
 660
 661         /*
 662          * The attr probably isn't going to be needed in most cases,
 663          * so don't fail completely on error.
 664          */
 665         device_create_file(dev, &dev_attr_idle_state);
 666
 667         dev_info(dev, "registered %d multiplexed busses for I2C %s %s\n",
 668                  num, data->chip->muxtype == pca954x_ismux
 669                                 ? "mux" : "switch", client->name);
 670
 671         return 0;
 672
 673 fail_cleanup:
 674         pca954x_cleanup(muxc);
 675         return ret;
 676 }
 677
 678 static void pca954x_remove(struct i2c_client *client)
 679 {
 680         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 681
 682         device_remove_file(&client->dev, &dev_attr_idle_state);
 683
 684         pca954x_cleanup(muxc);
 685 }
 686
 687 static int pca954x_resume(struct device *dev)
 688 {
 689         struct i2c_client *client = to_i2c_client(dev);
 690         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 691         struct pca954x *data = i2c_mux_priv(muxc);
 692         int ret;
 693
 694         ret = pca954x_init(client, data);
 695         if (ret < 0)
 696                 dev_err(&client->dev, "failed to verify mux presence\n");
 697
 698         return ret;
 699 }
 700
 701 static DEFINE_SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
 702
 703 static struct i2c_driver pca954x_driver = {
 704         .driver         = {
 705                 .name   = "pca954x",
 706                 .pm     = pm_sleep_ptr(&pca954x_pm),
 707                 .of_match_table = pca954x_of_match,
 708         },
 709         .probe          = pca954x_probe,
 710         .remove         = pca954x_remove,
 711         .id_table       = pca954x_id,
 712 };
 713
 714 module_i2c_driver(pca954x_driver);
 715
 716 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 717 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
 718 MODULE_LICENSE("GPL v2");