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  * 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                          const struct i2c_device_id *id)
 416 {
 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 int 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         return 0;
 532 }
 533
 534 #ifdef CONFIG_PM_SLEEP
 535 static int pca954x_resume(struct device *dev)
 536 {
 537         struct i2c_client *client = to_i2c_client(dev);
 538         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 539         struct pca954x *data = i2c_mux_priv(muxc);
 540         int ret;
 541
 542         ret = pca954x_init(client, data);
 543         if (ret < 0)
 544                 dev_err(&client->dev, "failed to verify mux presence\n");
 545
 546         return ret;
 547 }
 548 #endif
 549
 550 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
 551
 552 static struct i2c_driver pca954x_driver = {
 553         .driver         = {
 554                 .name   = "pca954x",
 555                 .pm     = &pca954x_pm,
 556                 .of_match_table = pca954x_of_match,
 557         },
 558         .probe          = pca954x_probe,
 559         .remove         = pca954x_remove,
 560         .id_table       = pca954x_id,
 561 };
 562
 563 module_i2c_driver(pca954x_driver);
 564
 565 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 566 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
 567 MODULE_LICENSE("GPL v2");