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/delay.h>
  40 #include <linux/gpio/consumer.h>
  41 #include <linux/i2c.h>
  42 #include <linux/i2c-mux.h>
  43 #include <linux/interrupt.h>
  44 #include <linux/irq.h>
  45 #include <linux/module.h>
  46 #include <linux/of.h>
  47 #include <linux/of_device.h>
  48 #include <linux/of_irq.h>
  49 #include <linux/platform_data/pca954x.h>
  50 #include <linux/pm.h>
  51 #include <linux/slab.h>
  52 #include <linux/spinlock.h>
  53
  54 #define PCA954X_MAX_NCHANS 8
  55
  56 #define PCA954X_IRQ_OFFSET 4
  57
  58 enum pca_type {
  59         pca_9540,
  60         pca_9542,
  61         pca_9543,
  62         pca_9544,
  63         pca_9545,
  64         pca_9546,
  65         pca_9547,
  66         pca_9548,
  67         pca_9846,
  68         pca_9847,
  69         pca_9848,
  70         pca_9849,
  71 };
  72
  73 struct chip_desc {
  74         u8 nchans;
  75         u8 enable;      /* used for muxes only */
  76         u8 has_irq;
  77         enum muxtype {
  78                 pca954x_ismux = 0,
  79                 pca954x_isswi
  80         } muxtype;
  81         struct i2c_device_identity id;
  82 };
  83
  84 struct pca954x {
  85         const struct chip_desc *chip;
  86
  87         u8 last_chan;           /* last register value */
  88         u8 deselect;
  89         struct i2c_client *client;
  90
  91         struct irq_domain *irq;
  92         unsigned int irq_mask;
  93         raw_spinlock_t lock;
  94 };
  95
  96 /* Provide specs for the PCA954x types we know about */
  97 static const struct chip_desc chips[] = {
  98         [pca_9540] = {
  99                 .nchans = 2,
 100                 .enable = 0x4,
 101                 .muxtype = pca954x_ismux,
 102                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 103         },
 104         [pca_9542] = {
 105                 .nchans = 2,
 106                 .enable = 0x4,
 107                 .has_irq = 1,
 108                 .muxtype = pca954x_ismux,
 109                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 110         },
 111         [pca_9543] = {
 112                 .nchans = 2,
 113                 .has_irq = 1,
 114                 .muxtype = pca954x_isswi,
 115                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 116         },
 117         [pca_9544] = {
 118                 .nchans = 4,
 119                 .enable = 0x4,
 120                 .has_irq = 1,
 121                 .muxtype = pca954x_ismux,
 122                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 123         },
 124         [pca_9545] = {
 125                 .nchans = 4,
 126                 .has_irq = 1,
 127                 .muxtype = pca954x_isswi,
 128                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 129         },
 130         [pca_9546] = {
 131                 .nchans = 4,
 132                 .muxtype = pca954x_isswi,
 133                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 134         },
 135         [pca_9547] = {
 136                 .nchans = 8,
 137                 .enable = 0x8,
 138                 .muxtype = pca954x_ismux,
 139                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 140         },
 141         [pca_9548] = {
 142                 .nchans = 8,
 143                 .muxtype = pca954x_isswi,
 144                 .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
 145         },
 146         [pca_9846] = {
 147                 .nchans = 4,
 148                 .muxtype = pca954x_isswi,
 149                 .id = {
 150                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 151                         .part_id = 0x10b,
 152                 },
 153         },
 154         [pca_9847] = {
 155                 .nchans = 8,
 156                 .enable = 0x8,
 157                 .muxtype = pca954x_ismux,
 158                 .id = {
 159                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 160                         .part_id = 0x108,
 161                 },
 162         },
 163         [pca_9848] = {
 164                 .nchans = 8,
 165                 .muxtype = pca954x_isswi,
 166                 .id = {
 167                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 168                         .part_id = 0x10a,
 169                 },
 170         },
 171         [pca_9849] = {
 172                 .nchans = 4,
 173                 .enable = 0x4,
 174                 .muxtype = pca954x_ismux,
 175                 .id = {
 176                         .manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
 177                         .part_id = 0x109,
 178                 },
 179         },
 180 };
 181
 182 static const struct i2c_device_id pca954x_id[] = {
 183         { "pca9540", pca_9540 },
 184         { "pca9542", pca_9542 },
 185         { "pca9543", pca_9543 },
 186         { "pca9544", pca_9544 },
 187         { "pca9545", pca_9545 },
 188         { "pca9546", pca_9546 },
 189         { "pca9547", pca_9547 },
 190         { "pca9548", pca_9548 },
 191         { "pca9846", pca_9846 },
 192         { "pca9847", pca_9847 },
 193         { "pca9848", pca_9848 },
 194         { "pca9849", pca_9849 },
 195         { }
 196 };
 197 MODULE_DEVICE_TABLE(i2c, pca954x_id);
 198
 199 #ifdef CONFIG_OF
 200 static const struct of_device_id pca954x_of_match[] = {
 201         { .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
 202         { .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
 203         { .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
 204         { .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
 205         { .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
 206         { .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
 207         { .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
 208         { .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
 209         { .compatible = "nxp,pca9846", .data = &chips[pca_9846] },
 210         { .compatible = "nxp,pca9847", .data = &chips[pca_9847] },
 211         { .compatible = "nxp,pca9848", .data = &chips[pca_9848] },
 212         { .compatible = "nxp,pca9849", .data = &chips[pca_9849] },
 213         {}
 214 };
 215 MODULE_DEVICE_TABLE(of, pca954x_of_match);
 216 #endif
 217
 218 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
 219    for this as they will try to lock adapter a second time */
 220 static int pca954x_reg_write(struct i2c_adapter *adap,
 221                              struct i2c_client *client, u8 val)
 222 {
 223         union i2c_smbus_data dummy;
 224
 225         return __i2c_smbus_xfer(adap, client->addr, client->flags,
 226                                 I2C_SMBUS_WRITE, val,
 227                                 I2C_SMBUS_BYTE, &dummy);
 228 }
 229
 230 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
 231 {
 232         struct pca954x *data = i2c_mux_priv(muxc);
 233         struct i2c_client *client = data->client;
 234         const struct chip_desc *chip = data->chip;
 235         u8 regval;
 236         int ret = 0;
 237
 238         /* we make switches look like muxes, not sure how to be smarter */
 239         if (chip->muxtype == pca954x_ismux)
 240                 regval = chan | chip->enable;
 241         else
 242                 regval = 1 << chan;
 243
 244         /* Only select the channel if its different from the last channel */
 245         if (data->last_chan != regval) {
 246                 ret = pca954x_reg_write(muxc->parent, client, regval);
 247                 data->last_chan = ret < 0 ? 0 : regval;
 248         }
 249
 250         return ret;
 251 }
 252
 253 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
 254 {
 255         struct pca954x *data = i2c_mux_priv(muxc);
 256         struct i2c_client *client = data->client;
 257
 258         if (!(data->deselect & (1 << chan)))
 259                 return 0;
 260
 261         /* Deselect active channel */
 262         data->last_chan = 0;
 263         return pca954x_reg_write(muxc->parent, client, data->last_chan);
 264 }
 265
 266 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
 267 {
 268         struct pca954x *data = dev_id;
 269         unsigned int child_irq;
 270         int ret, i, handled = 0;
 271
 272         ret = i2c_smbus_read_byte(data->client);
 273         if (ret < 0)
 274                 return IRQ_NONE;
 275
 276         for (i = 0; i < data->chip->nchans; i++) {
 277                 if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
 278                         child_irq = irq_linear_revmap(data->irq, i);
 279                         handle_nested_irq(child_irq);
 280                         handled++;
 281                 }
 282         }
 283         return handled ? IRQ_HANDLED : IRQ_NONE;
 284 }
 285
 286 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
 287 {
 288         if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
 289                 return -EINVAL;
 290         return 0;
 291 }
 292
 293 static struct irq_chip pca954x_irq_chip = {
 294         .name = "i2c-mux-pca954x",
 295         .irq_set_type = pca954x_irq_set_type,
 296 };
 297
 298 static int pca954x_irq_setup(struct i2c_mux_core *muxc)
 299 {
 300         struct pca954x *data = i2c_mux_priv(muxc);
 301         struct i2c_client *client = data->client;
 302         int c, irq;
 303
 304         if (!data->chip->has_irq || client->irq <= 0)
 305                 return 0;
 306
 307         raw_spin_lock_init(&data->lock);
 308
 309         data->irq = irq_domain_add_linear(client->dev.of_node,
 310                                           data->chip->nchans,
 311                                           &irq_domain_simple_ops, data);
 312         if (!data->irq)
 313                 return -ENODEV;
 314
 315         for (c = 0; c < data->chip->nchans; c++) {
 316                 irq = irq_create_mapping(data->irq, c);
 317                 if (!irq) {
 318                         dev_err(&client->dev, "failed irq create map\n");
 319                         return -EINVAL;
 320                 }
 321                 irq_set_chip_data(irq, data);
 322                 irq_set_chip_and_handler(irq, &pca954x_irq_chip,
 323                         handle_simple_irq);
 324         }
 325
 326         return 0;
 327 }
 328
 329 static void pca954x_cleanup(struct i2c_mux_core *muxc)
 330 {
 331         struct pca954x *data = i2c_mux_priv(muxc);
 332         int c, irq;
 333
 334         if (data->irq) {
 335                 for (c = 0; c < data->chip->nchans; c++) {
 336                         irq = irq_find_mapping(data->irq, c);
 337                         irq_dispose_mapping(irq);
 338                 }
 339                 irq_domain_remove(data->irq);
 340         }
 341         i2c_mux_del_adapters(muxc);
 342 }
 343
 344 /*
 345  * I2C init/probing/exit functions
 346  */
 347 static int pca954x_probe(struct i2c_client *client,
 348                          const struct i2c_device_id *id)
 349 {
 350         struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
 351         struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
 352         struct device *dev = &client->dev;
 353         struct device_node *np = dev->of_node;
 354         bool idle_disconnect_dt;
 355         struct gpio_desc *gpio;
 356         int num, force, class;
 357         struct i2c_mux_core *muxc;
 358         struct pca954x *data;
 359         int ret;
 360
 361         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
 362                 return -ENODEV;
 363
 364         muxc = i2c_mux_alloc(adap, dev, PCA954X_MAX_NCHANS, sizeof(*data), 0,
 365                              pca954x_select_chan, pca954x_deselect_mux);
 366         if (!muxc)
 367                 return -ENOMEM;
 368         data = i2c_mux_priv(muxc);
 369
 370         i2c_set_clientdata(client, muxc);
 371         data->client = client;
 372
 373         /* Reset the mux if a reset GPIO is specified. */
 374         gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 375         if (IS_ERR(gpio))
 376                 return PTR_ERR(gpio);
 377         if (gpio) {
 378                 udelay(1);
 379                 gpiod_set_value_cansleep(gpio, 0);
 380                 /* Give the chip some time to recover. */
 381                 udelay(1);
 382         }
 383
 384         data->chip = of_device_get_match_data(dev);
 385         if (!data->chip)
 386                 data->chip = &chips[id->driver_data];
 387
 388         if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {
 389                 struct i2c_device_identity id;
 390
 391                 ret = i2c_get_device_id(client, &id);
 392                 if (ret && ret != -EOPNOTSUPP)
 393                         return ret;
 394
 395                 if (!ret &&
 396                     (id.manufacturer_id != data->chip->id.manufacturer_id ||
 397                      id.part_id != data->chip->id.part_id)) {
 398                         dev_warn(dev, "unexpected device id %03x-%03x-%x\n",
 399                                  id.manufacturer_id, id.part_id,
 400                                  id.die_revision);
 401                         return -ENODEV;
 402                 }
 403         }
 404
 405         /* Write the mux register at addr to verify
 406          * that the mux is in fact present. This also
 407          * initializes the mux to disconnected state.
 408          */
 409         if (i2c_smbus_write_byte(client, 0) < 0) {
 410                 dev_warn(dev, "probe failed\n");
 411                 return -ENODEV;
 412         }
 413
 414         data->last_chan = 0;               /* force the first selection */
 415
 416         idle_disconnect_dt = np &&
 417                 of_property_read_bool(np, "i2c-mux-idle-disconnect");
 418
 419         ret = pca954x_irq_setup(muxc);
 420         if (ret)
 421                 goto fail_cleanup;
 422
 423         /* Now create an adapter for each channel */
 424         for (num = 0; num < data->chip->nchans; num++) {
 425                 bool idle_disconnect_pd = false;
 426
 427                 force = 0;                        /* dynamic adap number */
 428                 class = 0;                        /* no class by default */
 429                 if (pdata) {
 430                         if (num < pdata->num_modes) {
 431                                 /* force static number */
 432                                 force = pdata->modes[num].adap_id;
 433                                 class = pdata->modes[num].class;
 434                         } else
 435                                 /* discard unconfigured channels */
 436                                 break;
 437                         idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
 438                 }
 439                 data->deselect |= (idle_disconnect_pd ||
 440                                    idle_disconnect_dt) << num;
 441
 442                 ret = i2c_mux_add_adapter(muxc, force, num, class);
 443                 if (ret)
 444                         goto fail_cleanup;
 445         }
 446
 447         if (data->irq) {
 448                 ret = devm_request_threaded_irq(dev, data->client->irq,
 449                                                 NULL, pca954x_irq_handler,
 450                                                 IRQF_ONESHOT | IRQF_SHARED,
 451                                                 "pca954x", data);
 452                 if (ret)
 453                         goto fail_cleanup;
 454         }
 455
 456         dev_info(dev, "registered %d multiplexed busses for I2C %s %s\n",
 457                  num, data->chip->muxtype == pca954x_ismux
 458                                 ? "mux" : "switch", client->name);
 459
 460         return 0;
 461
 462 fail_cleanup:
 463         pca954x_cleanup(muxc);
 464         return ret;
 465 }
 466
 467 static int pca954x_remove(struct i2c_client *client)
 468 {
 469         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 470
 471         pca954x_cleanup(muxc);
 472         return 0;
 473 }
 474
 475 #ifdef CONFIG_PM_SLEEP
 476 static int pca954x_resume(struct device *dev)
 477 {
 478         struct i2c_client *client = to_i2c_client(dev);
 479         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 480         struct pca954x *data = i2c_mux_priv(muxc);
 481
 482         data->last_chan = 0;
 483         return i2c_smbus_write_byte(client, 0);
 484 }
 485 #endif
 486
 487 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
 488
 489 static struct i2c_driver pca954x_driver = {
 490         .driver         = {
 491                 .name   = "pca954x",
 492                 .pm     = &pca954x_pm,
 493                 .of_match_table = of_match_ptr(pca954x_of_match),
 494         },
 495         .probe          = pca954x_probe,
 496         .remove         = pca954x_remove,
 497         .id_table       = pca954x_id,
 498 };
 499
 500 module_i2c_driver(pca954x_driver);
 501
 502 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 503 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
 504 MODULE_LICENSE("GPL v2");