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

   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/gpio/consumer.h>
  40 #include <linux/i2c.h>
  41 #include <linux/i2c-mux.h>
  42 #include <linux/interrupt.h>
  43 #include <linux/irq.h>
  44 #include <linux/module.h>
  45 #include <linux/of.h>
  46 #include <linux/of_device.h>
  47 #include <linux/of_irq.h>
  48 #include <linux/platform_data/pca954x.h>
  49 #include <linux/pm.h>
  50 #include <linux/slab.h>
  51 #include <linux/spinlock.h>
  52
  53 #define PCA954X_MAX_NCHANS 8
  54
  55 #define PCA954X_IRQ_OFFSET 4
  56
  57 enum pca_type {
  58         pca_9540,
  59         pca_9542,
  60         pca_9543,
  61         pca_9544,
  62         pca_9545,
  63         pca_9546,
  64         pca_9547,
  65         pca_9548,
  66         pca_9846,
  67         pca_9847,
  68         pca_9848,
  69         pca_9849,
  70 };
  71
  72 struct chip_desc {
  73         u8 nchans;
  74         u8 enable;      /* used for muxes only */
  75         u8 has_irq;
  76         enum muxtype {
  77                 pca954x_ismux = 0,
  78                 pca954x_isswi
  79         } muxtype;
  80         struct i2c_device_identity id;
  81 };
  82
  83 struct pca954x {
  84         const struct chip_desc *chip;
  85
  86         u8 last_chan;           /* last register value */
  87         u8 deselect;
  88         struct i2c_client *client;
  89
  90         struct irq_domain *irq;
  91         unsigned int irq_mask;
  92         raw_spinlock_t lock;
  93 };
  94
  95 /* Provide specs for the PCA954x types we know about */
  96 static const struct chip_desc chips[] = {
  97         [pca_9540] = {
  98                 .nchans = 2,
  99                 .enable = 0x4,
 100                 .muxtype = pca954x_ismux,
 101                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 102         },
 103         [pca_9542] = {
 104                 .nchans = 2,
 105                 .enable = 0x4,
 106                 .has_irq = 1,
 107                 .muxtype = pca954x_ismux,
 108                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 109         },
 110         [pca_9543] = {
 111                 .nchans = 2,
 112                 .has_irq = 1,
 113                 .muxtype = pca954x_isswi,
 114                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 115         },
 116         [pca_9544] = {
 117                 .nchans = 4,
 118                 .enable = 0x4,
 119                 .has_irq = 1,
 120                 .muxtype = pca954x_ismux,
 121                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 122         },
 123         [pca_9545] = {
 124                 .nchans = 4,
 125                 .has_irq = 1,
 126                 .muxtype = pca954x_isswi,
 127                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 128         },
 129         [pca_9546] = {
 130                 .nchans = 4,
 131                 .muxtype = pca954x_isswi,
 132                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 133         },
 134         [pca_9547] = {
 135                 .nchans = 8,
 136                 .enable = 0x8,
 137                 .muxtype = pca954x_ismux,
 138                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 139         },
 140         [pca_9548] = {
 141                 .nchans = 8,
 142                 .muxtype = pca954x_isswi,
 143                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 144         },
 145         [pca_9846] = {
 146                 .nchans = 4,
 147                 .muxtype = pca954x_isswi,
 148                 .id = {
 149                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 150                         .part_id = 0x10b,
 151                 },
 152         },
 153         [pca_9847] = {
 154                 .nchans = 8,
 155                 .enable = 0x8,
 156                 .muxtype = pca954x_ismux,
 157                 .id = {
 158                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 159                         .part_id = 0x108,
 160                 },
 161         },
 162         [pca_9848] = {
 163                 .nchans = 8,
 164                 .muxtype = pca954x_isswi,
 165                 .id = {
 166                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 167                         .part_id = 0x10a,
 168                 },
 169         },
 170         [pca_9849] = {
 171                 .nchans = 4,
 172                 .enable = 0x4,
 173                 .muxtype = pca954x_ismux,
 174                 .id = {
 175                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 176                         .part_id = 0x109,
 177                 },
 178         },
 179 };
 180
 181 static const struct i2c_device_id pca954x_id[] = {
 182         { "pca9540", pca_9540 },
 183         { "pca9542", pca_9542 },
 184         { "pca9543", pca_9543 },
 185         { "pca9544", pca_9544 },
 186         { "pca9545", pca_9545 },
 187         { "pca9546", pca_9546 },
 188         { "pca9547", pca_9547 },
 189         { "pca9548", pca_9548 },
 190         { "pca9846", pca_9846 },
 191         { "pca9847", pca_9847 },
 192         { "pca9848", pca_9848 },
 193         { "pca9849", pca_9849 },
 194         { }
 195 };
 196 MODULE_DEVICE_TABLE(i2c, pca954x_id);
 197
 198 #ifdef CONFIG_OF
 199 static const struct of_device_id pca954x_of_match[] = {
 200         { .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
 201         { .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
 202         { .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
 203         { .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
 204         { .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
 205         { .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
 206         { .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
 207         { .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
 208         { .compatible = "nxp,pca9846", .data = &chips[pca_9846] },
 209         { .compatible = "nxp,pca9847", .data = &chips[pca_9847] },
 210         { .compatible = "nxp,pca9848", .data = &chips[pca_9848] },
 211         { .compatible = "nxp,pca9849", .data = &chips[pca_9849] },
 212         {}
 213 };
 214 MODULE_DEVICE_TABLE(of, pca954x_of_match);
 215 #endif
 216
 217 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
 218    for this as they will try to lock adapter a second time */
 219 static int pca954x_reg_write(struct i2c_adapter *adap,
 220                              struct i2c_client *client, u8 val)
 221 {
 222         int ret = -ENODEV;
 223
 224         if (adap->algo->master_xfer) {
 225                 struct i2c_msg msg;
 226                 char buf[1];
 227
 228                 msg.addr = client->addr;
 229                 msg.flags = 0;
 230                 msg.len = 1;
 231                 buf[0] = val;
 232                 msg.buf = buf;
 233                 ret = __i2c_transfer(adap, &msg, 1);
 234
 235                 if (ret >= 0 && ret != 1)
 236                         ret = -EREMOTEIO;
 237         } else {
 238                 union i2c_smbus_data data;
 239                 ret = adap->algo->smbus_xfer(adap, client->addr,
 240                                              client->flags,
 241                                              I2C_SMBUS_WRITE,
 242                                              val, I2C_SMBUS_BYTE, &data);
 243         }
 244
 245         return ret;
 246 }
 247
 248 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
 249 {
 250         struct pca954x *data = i2c_mux_priv(muxc);
 251         struct i2c_client *client = data->client;
 252         const struct chip_desc *chip = data->chip;
 253         u8 regval;
 254         int ret = 0;
 255
 256         /* we make switches look like muxes, not sure how to be smarter */
 257         if (chip->muxtype == pca954x_ismux)
 258                 regval = chan | chip->enable;
 259         else
 260                 regval = 1 << chan;
 261
 262         /* Only select the channel if its different from the last channel */
 263         if (data->last_chan != regval) {
 264                 ret = pca954x_reg_write(muxc->parent, client, regval);
 265                 data->last_chan = ret < 0 ? 0 : regval;
 266         }
 267
 268         return ret;
 269 }
 270
 271 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
 272 {
 273         struct pca954x *data = i2c_mux_priv(muxc);
 274         struct i2c_client *client = data->client;
 275
 276         if (!(data->deselect & (1 << chan)))
 277                 return 0;
 278
 279         /* Deselect active channel */
 280         data->last_chan = 0;
 281         return pca954x_reg_write(muxc->parent, client, data->last_chan);
 282 }
 283
 284 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
 285 {
 286         struct pca954x *data = dev_id;
 287         unsigned int child_irq;
 288         int ret, i, handled = 0;
 289
 290         ret = i2c_smbus_read_byte(data->client);
 291         if (ret < 0)
 292                 return IRQ_NONE;
 293
 294         for (i = 0; i < data->chip->nchans; i++) {
 295                 if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
 296                         child_irq = irq_linear_revmap(data->irq, i);
 297                         handle_nested_irq(child_irq);
 298                         handled++;
 299                 }
 300         }
 301         return handled ? IRQ_HANDLED : IRQ_NONE;
 302 }
 303
 304 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
 305 {
 306         if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
 307                 return -EINVAL;
 308         return 0;
 309 }
 310
 311 static struct irq_chip pca954x_irq_chip = {
 312         .name = "i2c-mux-pca954x",
 313         .irq_set_type = pca954x_irq_set_type,
 314 };
 315
 316 static int pca954x_irq_setup(struct i2c_mux_core *muxc)
 317 {
 318         struct pca954x *data = i2c_mux_priv(muxc);
 319         struct i2c_client *client = data->client;
 320         int c, irq;
 321
 322         if (!data->chip->has_irq || client->irq <= 0)
 323                 return 0;
 324
 325         raw_spin_lock_init(&data->lock);
 326
 327         data->irq = irq_domain_add_linear(client->dev.of_node,
 328                                           data->chip->nchans,
 329                                           &irq_domain_simple_ops, data);
 330         if (!data->irq)
 331                 return -ENODEV;
 332
 333         for (c = 0; c < data->chip->nchans; c++) {
 334                 irq = irq_create_mapping(data->irq, c);
 335                 if (!irq) {
 336                         dev_err(&client->dev, "failed irq create map\n");
 337                         return -EINVAL;
 338                 }
 339                 irq_set_chip_data(irq, data);
 340                 irq_set_chip_and_handler(irq, &pca954x_irq_chip,
 341                         handle_simple_irq);
 342         }
 343
 344         return 0;
 345 }
 346
 347 static void pca954x_cleanup(struct i2c_mux_core *muxc)
 348 {
 349         struct pca954x *data = i2c_mux_priv(muxc);
 350         int c, irq;
 351
 352         if (data->irq) {
 353                 for (c = 0; c < data->chip->nchans; c++) {
 354                         irq = irq_find_mapping(data->irq, c);
 355                         irq_dispose_mapping(irq);
 356                 }
 357                 irq_domain_remove(data->irq);
 358         }
 359         i2c_mux_del_adapters(muxc);
 360 }
 361
 362 /*
 363  * I2C init/probing/exit functions
 364  */
 365 static int pca954x_probe(struct i2c_client *client,
 366                          const struct i2c_device_id *id)
 367 {
 368         struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
 369         struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
 370         struct device_node *of_node = client->dev.of_node;
 371         bool idle_disconnect_dt;
 372         struct gpio_desc *gpio;
 373         int num, force, class;
 374         struct i2c_mux_core *muxc;
 375         struct pca954x *data;
 376         const struct of_device_id *match;
 377         int ret;
 378
 379         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
 380                 return -ENODEV;
 381
 382         muxc = i2c_mux_alloc(adap, &client->dev,
 383                              PCA954X_MAX_NCHANS, sizeof(*data), 0,
 384                              pca954x_select_chan, pca954x_deselect_mux);
 385         if (!muxc)
 386                 return -ENOMEM;
 387         data = i2c_mux_priv(muxc);
 388
 389         i2c_set_clientdata(client, muxc);
 390         data->client = client;
 391
 392         /* Get the mux out of reset if a reset GPIO is specified. */
 393         gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
 394         if (IS_ERR(gpio))
 395                 return PTR_ERR(gpio);
 396
 397         match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);
 398         if (match)
 399                 data->chip = of_device_get_match_data(&client->dev);
 400         else
 401                 data->chip = &chips[id->driver_data];
 402
 403         if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {
 404                 struct i2c_device_identity id;
 405
 406                 ret = i2c_get_device_id(client, &id);
 407                 if (ret && ret != -EOPNOTSUPP)
 408                         return ret;
 409
 410                 if (!ret &&
 411                     (id.manufacturer_id != data->chip->id.manufacturer_id ||
 412                      id.part_id != data->chip->id.part_id)) {
 413                         dev_warn(&client->dev,
 414                                  "unexpected device id %03x-%03x-%x\n",
 415                                  id.manufacturer_id, id.part_id,
 416                                  id.die_revision);
 417                         return -ENODEV;
 418                 }
 419         }
 420
 421         /* Write the mux register at addr to verify
 422          * that the mux is in fact present. This also
 423          * initializes the mux to disconnected state.
 424          */
 425         if (i2c_smbus_write_byte(client, 0) < 0) {
 426                 dev_warn(&client->dev, "probe failed\n");
 427                 return -ENODEV;
 428         }
 429
 430         data->last_chan = 0;               /* force the first selection */
 431
 432         idle_disconnect_dt = of_node &&
 433                 of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
 434
 435         ret = pca954x_irq_setup(muxc);
 436         if (ret)
 437                 goto fail_cleanup;
 438
 439         /* Now create an adapter for each channel */
 440         for (num = 0; num < data->chip->nchans; num++) {
 441                 bool idle_disconnect_pd = false;
 442
 443                 force = 0;                        /* dynamic adap number */
 444                 class = 0;                        /* no class by default */
 445                 if (pdata) {
 446                         if (num < pdata->num_modes) {
 447                                 /* force static number */
 448                                 force = pdata->modes[num].adap_id;
 449                                 class = pdata->modes[num].class;
 450                         } else
 451                                 /* discard unconfigured channels */
 452                                 break;
 453                         idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
 454                 }
 455                 data->deselect |= (idle_disconnect_pd ||
 456                                    idle_disconnect_dt) << num;
 457
 458                 ret = i2c_mux_add_adapter(muxc, force, num, class);
 459                 if (ret)
 460                         goto fail_cleanup;
 461         }
 462
 463         if (data->irq) {
 464                 ret = devm_request_threaded_irq(&client->dev, data->client->irq,
 465                                                 NULL, pca954x_irq_handler,
 466                                                 IRQF_ONESHOT | IRQF_SHARED,
 467                                                 "pca954x", data);
 468                 if (ret)
 469                         goto fail_cleanup;
 470         }
 471
 472         dev_info(&client->dev,
 473                  "registered %d multiplexed busses for I2C %s %s\n",
 474                  num, data->chip->muxtype == pca954x_ismux
 475                                 ? "mux" : "switch", client->name);
 476
 477         return 0;
 478
 479 fail_cleanup:
 480         pca954x_cleanup(muxc);
 481         return ret;
 482 }
 483
 484 static int pca954x_remove(struct i2c_client *client)
 485 {
 486         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 487
 488         pca954x_cleanup(muxc);
 489         return 0;
 490 }
 491
 492 #ifdef CONFIG_PM_SLEEP
 493 static int pca954x_resume(struct device *dev)
 494 {
 495         struct i2c_client *client = to_i2c_client(dev);
 496         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 497         struct pca954x *data = i2c_mux_priv(muxc);
 498
 499         data->last_chan = 0;
 500         return i2c_smbus_write_byte(client, 0);
 501 }
 502 #endif
 503
 504 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
 505
 506 static struct i2c_driver pca954x_driver = {
 507         .driver         = {
 508                 .name   = "pca954x",
 509                 .pm     = &pca954x_pm,
 510                 .of_match_table = of_match_ptr(pca954x_of_match),
 511         },
 512         .probe          = pca954x_probe,
 513         .remove         = pca954x_remove,
 514         .id_table       = pca954x_id,
 515 };
 516
 517 module_i2c_driver(pca954x_driver);
 518
 519 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 520 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
 521 MODULE_LICENSE("GPL v2");