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 series of I2C multiplexer/switch chips
   8  * made by Philips Semiconductors.
   9  * This includes the:
  10  *       PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
  11  *       and PCA9548.
  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/acpi.h>
  39 #include <linux/device.h>
  40 #include <linux/gpio/consumer.h>
  41 #include <linux/i2c.h>
  42 #include <linux/i2c-mux.h>
  43 #include <linux/i2c/pca954x.h>
  44 #include <linux/interrupt.h>
  45 #include <linux/irq.h>
  46 #include <linux/module.h>
  47 #include <linux/of.h>
  48 #include <linux/of_device.h>
  49 #include <linux/of_irq.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 };
  68
  69 struct chip_desc {
  70         u8 nchans;
  71         u8 enable;      /* used for muxes only */
  72         u8 has_irq;
  73         enum muxtype {
  74                 pca954x_ismux = 0,
  75                 pca954x_isswi
  76         } muxtype;
  77 };
  78
  79 struct pca954x {
  80         const struct chip_desc *chip;
  81
  82         u8 last_chan;           /* last register value */
  83         u8 deselect;
  84         struct i2c_client *client;
  85
  86         struct irq_domain *irq;
  87         unsigned int irq_mask;
  88         spinlock_t lock;
  89 };
  90
  91 /* Provide specs for the PCA954x types we know about */
  92 static const struct chip_desc chips[] = {
  93         [pca_9540] = {
  94                 .nchans = 2,
  95                 .enable = 0x4,
  96                 .muxtype = pca954x_ismux,
  97         },
  98         [pca_9542] = {
  99                 .nchans = 2,
 100                 .enable = 0x4,
 101                 .has_irq = 1,
 102                 .muxtype = pca954x_ismux,
 103         },
 104         [pca_9543] = {
 105                 .nchans = 2,
 106                 .has_irq = 1,
 107                 .muxtype = pca954x_isswi,
 108         },
 109         [pca_9544] = {
 110                 .nchans = 4,
 111                 .enable = 0x4,
 112                 .has_irq = 1,
 113                 .muxtype = pca954x_ismux,
 114         },
 115         [pca_9545] = {
 116                 .nchans = 4,
 117                 .has_irq = 1,
 118                 .muxtype = pca954x_isswi,
 119         },
 120         [pca_9547] = {
 121                 .nchans = 8,
 122                 .enable = 0x8,
 123                 .muxtype = pca954x_ismux,
 124         },
 125         [pca_9548] = {
 126                 .nchans = 8,
 127                 .muxtype = pca954x_isswi,
 128         },
 129 };
 130
 131 static const struct i2c_device_id pca954x_id[] = {
 132         { "pca9540", pca_9540 },
 133         { "pca9542", pca_9542 },
 134         { "pca9543", pca_9543 },
 135         { "pca9544", pca_9544 },
 136         { "pca9545", pca_9545 },
 137         { "pca9546", pca_9545 },
 138         { "pca9547", pca_9547 },
 139         { "pca9548", pca_9548 },
 140         { }
 141 };
 142 MODULE_DEVICE_TABLE(i2c, pca954x_id);
 143
 144 #ifdef CONFIG_ACPI
 145 static const struct acpi_device_id pca954x_acpi_ids[] = {
 146         { .id = "PCA9540", .driver_data = pca_9540 },
 147         { .id = "PCA9542", .driver_data = pca_9542 },
 148         { .id = "PCA9543", .driver_data = pca_9543 },
 149         { .id = "PCA9544", .driver_data = pca_9544 },
 150         { .id = "PCA9545", .driver_data = pca_9545 },
 151         { .id = "PCA9546", .driver_data = pca_9545 },
 152         { .id = "PCA9547", .driver_data = pca_9547 },
 153         { .id = "PCA9548", .driver_data = pca_9548 },
 154         { }
 155 };
 156 MODULE_DEVICE_TABLE(acpi, pca954x_acpi_ids);
 157 #endif
 158
 159 #ifdef CONFIG_OF
 160 static const struct of_device_id pca954x_of_match[] = {
 161         { .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
 162         { .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
 163         { .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
 164         { .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
 165         { .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
 166         { .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
 167         { .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
 168         { .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
 169         {}
 170 };
 171 MODULE_DEVICE_TABLE(of, pca954x_of_match);
 172 #endif
 173
 174 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
 175    for this as they will try to lock adapter a second time */
 176 static int pca954x_reg_write(struct i2c_adapter *adap,
 177                              struct i2c_client *client, u8 val)
 178 {
 179         int ret = -ENODEV;
 180
 181         if (adap->algo->master_xfer) {
 182                 struct i2c_msg msg;
 183                 char buf[1];
 184
 185                 msg.addr = client->addr;
 186                 msg.flags = 0;
 187                 msg.len = 1;
 188                 buf[0] = val;
 189                 msg.buf = buf;
 190                 ret = __i2c_transfer(adap, &msg, 1);
 191
 192                 if (ret >= 0 && ret != 1)
 193                         ret = -EREMOTEIO;
 194         } else {
 195                 union i2c_smbus_data data;
 196                 ret = adap->algo->smbus_xfer(adap, client->addr,
 197                                              client->flags,
 198                                              I2C_SMBUS_WRITE,
 199                                              val, I2C_SMBUS_BYTE, &data);
 200         }
 201
 202         return ret;
 203 }
 204
 205 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
 206 {
 207         struct pca954x *data = i2c_mux_priv(muxc);
 208         struct i2c_client *client = data->client;
 209         const struct chip_desc *chip = data->chip;
 210         u8 regval;
 211         int ret = 0;
 212
 213         /* we make switches look like muxes, not sure how to be smarter */
 214         if (chip->muxtype == pca954x_ismux)
 215                 regval = chan | chip->enable;
 216         else
 217                 regval = 1 << chan;
 218
 219         /* Only select the channel if its different from the last channel */
 220         if (data->last_chan != regval) {
 221                 ret = pca954x_reg_write(muxc->parent, client, regval);
 222                 data->last_chan = ret < 0 ? 0 : regval;
 223         }
 224
 225         return ret;
 226 }
 227
 228 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
 229 {
 230         struct pca954x *data = i2c_mux_priv(muxc);
 231         struct i2c_client *client = data->client;
 232
 233         if (!(data->deselect & (1 << chan)))
 234                 return 0;
 235
 236         /* Deselect active channel */
 237         data->last_chan = 0;
 238         return pca954x_reg_write(muxc->parent, client, data->last_chan);
 239 }
 240
 241 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
 242 {
 243         struct pca954x *data = dev_id;
 244         unsigned int child_irq;
 245         int ret, i, handled = 0;
 246
 247         ret = i2c_smbus_read_byte(data->client);
 248         if (ret < 0)
 249                 return IRQ_NONE;
 250
 251         for (i = 0; i < data->chip->nchans; i++) {
 252                 if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
 253                         child_irq = irq_linear_revmap(data->irq, i);
 254                         handle_nested_irq(child_irq);
 255                         handled++;
 256                 }
 257         }
 258         return handled ? IRQ_HANDLED : IRQ_NONE;
 259 }
 260
 261 static void pca954x_irq_mask(struct irq_data *idata)
 262 {
 263         struct pca954x *data = irq_data_get_irq_chip_data(idata);
 264         unsigned int pos = idata->hwirq;
 265         unsigned long flags;
 266
 267         spin_lock_irqsave(&data->lock, flags);
 268
 269         data->irq_mask &= ~BIT(pos);
 270         if (!data->irq_mask)
 271                 disable_irq(data->client->irq);
 272
 273         spin_unlock_irqrestore(&data->lock, flags);
 274 }
 275
 276 static void pca954x_irq_unmask(struct irq_data *idata)
 277 {
 278         struct pca954x *data = irq_data_get_irq_chip_data(idata);
 279         unsigned int pos = idata->hwirq;
 280         unsigned long flags;
 281
 282         spin_lock_irqsave(&data->lock, flags);
 283
 284         if (!data->irq_mask)
 285                 enable_irq(data->client->irq);
 286         data->irq_mask |= BIT(pos);
 287
 288         spin_unlock_irqrestore(&data->lock, flags);
 289 }
 290
 291 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
 292 {
 293         if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
 294                 return -EINVAL;
 295         return 0;
 296 }
 297
 298 static struct irq_chip pca954x_irq_chip = {
 299         .name = "i2c-mux-pca954x",
 300         .irq_mask = pca954x_irq_mask,
 301         .irq_unmask = pca954x_irq_unmask,
 302         .irq_set_type = pca954x_irq_set_type,
 303 };
 304
 305 static int pca954x_irq_setup(struct i2c_mux_core *muxc)
 306 {
 307         struct pca954x *data = i2c_mux_priv(muxc);
 308         struct i2c_client *client = data->client;
 309         int c, err, irq;
 310
 311         if (!data->chip->has_irq || client->irq <= 0)
 312                 return 0;
 313
 314         spin_lock_init(&data->lock);
 315
 316         data->irq = irq_domain_add_linear(client->dev.of_node,
 317                                           data->chip->nchans,
 318                                           &irq_domain_simple_ops, data);
 319         if (!data->irq)
 320                 return -ENODEV;
 321
 322         for (c = 0; c < data->chip->nchans; c++) {
 323                 irq = irq_create_mapping(data->irq, c);
 324                 irq_set_chip_data(irq, data);
 325                 irq_set_chip_and_handler(irq, &pca954x_irq_chip,
 326                         handle_simple_irq);
 327         }
 328
 329         err = devm_request_threaded_irq(&client->dev, data->client->irq, NULL,
 330                                         pca954x_irq_handler,
 331                                         IRQF_ONESHOT | IRQF_SHARED,
 332                                         "pca954x", data);
 333         if (err)
 334                 goto err_req_irq;
 335
 336         disable_irq(data->client->irq);
 337
 338         return 0;
 339 err_req_irq:
 340         for (c = 0; c < data->chip->nchans; c++) {
 341                 irq = irq_find_mapping(data->irq, c);
 342                 irq_dispose_mapping(irq);
 343         }
 344         irq_domain_remove(data->irq);
 345
 346         return err;
 347 }
 348
 349 /*
 350  * I2C init/probing/exit functions
 351  */
 352 static int pca954x_probe(struct i2c_client *client,
 353                          const struct i2c_device_id *id)
 354 {
 355         struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
 356         struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
 357         struct device_node *of_node = client->dev.of_node;
 358         bool idle_disconnect_dt;
 359         struct gpio_desc *gpio;
 360         int num, force, class;
 361         struct i2c_mux_core *muxc;
 362         struct pca954x *data;
 363         const struct of_device_id *match;
 364         int ret;
 365
 366         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
 367                 return -ENODEV;
 368
 369         muxc = i2c_mux_alloc(adap, &client->dev,
 370                              PCA954X_MAX_NCHANS, sizeof(*data), 0,
 371                              pca954x_select_chan, pca954x_deselect_mux);
 372         if (!muxc)
 373                 return -ENOMEM;
 374         data = i2c_mux_priv(muxc);
 375
 376         i2c_set_clientdata(client, muxc);
 377         data->client = client;
 378
 379         /* Get the mux out of reset if a reset GPIO is specified. */
 380         gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
 381         if (IS_ERR(gpio))
 382                 return PTR_ERR(gpio);
 383
 384         /* Write the mux register at addr to verify
 385          * that the mux is in fact present. This also
 386          * initializes the mux to disconnected state.
 387          */
 388         if (i2c_smbus_write_byte(client, 0) < 0) {
 389                 dev_warn(&client->dev, "probe failed\n");
 390                 return -ENODEV;
 391         }
 392
 393         match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);
 394         if (match)
 395                 data->chip = of_device_get_match_data(&client->dev);
 396         else if (id)
 397                 data->chip = &chips[id->driver_data];
 398         else {
 399                 const struct acpi_device_id *acpi_id;
 400
 401                 acpi_id = acpi_match_device(ACPI_PTR(pca954x_acpi_ids),
 402                                                 &client->dev);
 403                 if (!acpi_id)
 404                         return -ENODEV;
 405                 data->chip = &chips[acpi_id->driver_data];
 406         }
 407
 408         data->last_chan = 0;               /* force the first selection */
 409
 410         idle_disconnect_dt = of_node &&
 411                 of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
 412
 413         ret = pca954x_irq_setup(muxc);
 414         if (ret)
 415                 goto fail_del_adapters;
 416
 417         /* Now create an adapter for each channel */
 418         for (num = 0; num < data->chip->nchans; num++) {
 419                 bool idle_disconnect_pd = false;
 420
 421                 force = 0;                        /* dynamic adap number */
 422                 class = 0;                        /* no class by default */
 423                 if (pdata) {
 424                         if (num < pdata->num_modes) {
 425                                 /* force static number */
 426                                 force = pdata->modes[num].adap_id;
 427                                 class = pdata->modes[num].class;
 428                         } else
 429                                 /* discard unconfigured channels */
 430                                 break;
 431                         idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
 432                 }
 433                 data->deselect |= (idle_disconnect_pd ||
 434                                    idle_disconnect_dt) << num;
 435
 436                 ret = i2c_mux_add_adapter(muxc, force, num, class);
 437
 438                 if (ret) {
 439                         dev_err(&client->dev,
 440                                 "failed to register multiplexed adapter"
 441                                 " %d as bus %d\n", num, force);
 442                         goto fail_del_adapters;
 443                 }
 444         }
 445
 446         dev_info(&client->dev,
 447                  "registered %d multiplexed busses for I2C %s %s\n",
 448                  num, data->chip->muxtype == pca954x_ismux
 449                                 ? "mux" : "switch", client->name);
 450
 451         return 0;
 452
 453 fail_del_adapters:
 454         i2c_mux_del_adapters(muxc);
 455         return ret;
 456 }
 457
 458 static int pca954x_remove(struct i2c_client *client)
 459 {
 460         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 461         struct pca954x *data = i2c_mux_priv(muxc);
 462         int c, irq;
 463
 464         if (data->irq) {
 465                 for (c = 0; c < data->chip->nchans; c++) {
 466                         irq = irq_find_mapping(data->irq, c);
 467                         irq_dispose_mapping(irq);
 468                 }
 469                 irq_domain_remove(data->irq);
 470         }
 471
 472         i2c_mux_del_adapters(muxc);
 473         return 0;
 474 }
 475
 476 #ifdef CONFIG_PM_SLEEP
 477 static int pca954x_resume(struct device *dev)
 478 {
 479         struct i2c_client *client = to_i2c_client(dev);
 480         struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 481         struct pca954x *data = i2c_mux_priv(muxc);
 482
 483         data->last_chan = 0;
 484         return i2c_smbus_write_byte(client, 0);
 485 }
 486 #endif
 487
 488 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
 489
 490 static struct i2c_driver pca954x_driver = {
 491         .driver         = {
 492                 .name   = "pca954x",
 493                 .pm     = &pca954x_pm,
 494                 .of_match_table = of_match_ptr(pca954x_of_match),
 495                 .acpi_match_table = ACPI_PTR(pca954x_acpi_ids),
 496         },
 497         .probe          = pca954x_probe,
 498         .remove         = pca954x_remove,
 499         .id_table       = pca954x_id,
 500 };
 501
 502 module_i2c_driver(pca954x_driver);
 503
 504 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 505 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
 506 MODULE_LICENSE("GPL v2");