1 /* 2 * Linux I2C core 3 * 4 * Copyright (C) 1995-99 Simon G. Vogl 5 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> 6 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and 7 * Michael Lawnick <michael.lawnick.ext@nsn.com> 8 * 9 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de> 10 * 11 * This program is free software; you can redistribute it and/or modify it 12 * under the terms of the GNU General Public License as published by the Free 13 * Software Foundation; either version 2 of the License, or (at your option) 14 * any later version. 15 * 16 * This program is distributed in the hope that it will be useful, but WITHOUT 17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 18 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. 19 */ 20 21 #define pr_fmt(fmt) "i2c-core: " fmt 22 23 #include <dt-bindings/i2c/i2c.h> 24 #include <linux/acpi.h> 25 #include <linux/clk/clk-conf.h> 26 #include <linux/completion.h> 27 #include <linux/delay.h> 28 #include <linux/err.h> 29 #include <linux/errno.h> 30 #include <linux/gpio/consumer.h> 31 #include <linux/i2c.h> 32 #include <linux/i2c-smbus.h> 33 #include <linux/idr.h> 34 #include <linux/init.h> 35 #include <linux/irqflags.h> 36 #include <linux/jump_label.h> 37 #include <linux/kernel.h> 38 #include <linux/module.h> 39 #include <linux/mutex.h> 40 #include <linux/of_device.h> 41 #include <linux/of.h> 42 #include <linux/of_irq.h> 43 #include <linux/pm_domain.h> 44 #include <linux/pm_runtime.h> 45 #include <linux/pm_wakeirq.h> 46 #include <linux/property.h> 47 #include <linux/rwsem.h> 48 #include <linux/slab.h> 49 50 #include "i2c-core.h" 51 52 #define CREATE_TRACE_POINTS 53 #include <trace/events/i2c.h> 54 55 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000 56 #define I2C_ADDR_OFFSET_SLAVE 0x1000 57 58 #define I2C_ADDR_7BITS_MAX 0x77 59 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1) 60 61 #define I2C_ADDR_DEVICE_ID 0x7c 62 63 /* 64 * core_lock protects i2c_adapter_idr, and guarantees that device detection, 65 * deletion of detected devices are serialized 66 */ 67 static DEFINE_MUTEX(core_lock); 68 static DEFINE_IDR(i2c_adapter_idr); 69 70 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); 71 72 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key); 73 static bool is_registered; 74 75 int i2c_transfer_trace_reg(void) 76 { 77 static_branch_inc(&i2c_trace_msg_key); 78 return 0; 79 } 80 81 void i2c_transfer_trace_unreg(void) 82 { 83 static_branch_dec(&i2c_trace_msg_key); 84 } 85 86 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, 87 const struct i2c_client *client) 88 { 89 if (!(id && client)) 90 return NULL; 91 92 while (id->name[0]) { 93 if (strcmp(client->name, id->name) == 0) 94 return id; 95 id++; 96 } 97 return NULL; 98 } 99 EXPORT_SYMBOL_GPL(i2c_match_id); 100 101 static int i2c_device_match(struct device *dev, struct device_driver *drv) 102 { 103 struct i2c_client *client = i2c_verify_client(dev); 104 struct i2c_driver *driver; 105 106 107 /* Attempt an OF style match */ 108 if (i2c_of_match_device(drv->of_match_table, client)) 109 return 1; 110 111 /* Then ACPI style match */ 112 if (acpi_driver_match_device(dev, drv)) 113 return 1; 114 115 driver = to_i2c_driver(drv); 116 117 /* Finally an I2C match */ 118 if (i2c_match_id(driver->id_table, client)) 119 return 1; 120 121 return 0; 122 } 123 124 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env) 125 { 126 struct i2c_client *client = to_i2c_client(dev); 127 int rc; 128 129 rc = of_device_uevent_modalias(dev, env); 130 if (rc != -ENODEV) 131 return rc; 132 133 rc = acpi_device_uevent_modalias(dev, env); 134 if (rc != -ENODEV) 135 return rc; 136 137 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name); 138 } 139 140 /* i2c bus recovery routines */ 141 static int get_scl_gpio_value(struct i2c_adapter *adap) 142 { 143 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod); 144 } 145 146 static void set_scl_gpio_value(struct i2c_adapter *adap, int val) 147 { 148 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val); 149 } 150 151 static int get_sda_gpio_value(struct i2c_adapter *adap) 152 { 153 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod); 154 } 155 156 static void set_sda_gpio_value(struct i2c_adapter *adap, int val) 157 { 158 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val); 159 } 160 161 static int i2c_generic_bus_free(struct i2c_adapter *adap) 162 { 163 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 164 int ret = -EOPNOTSUPP; 165 166 if (bri->get_bus_free) 167 ret = bri->get_bus_free(adap); 168 else if (bri->get_sda) 169 ret = bri->get_sda(adap); 170 171 if (ret < 0) 172 return ret; 173 174 return ret ? 0 : -EBUSY; 175 } 176 177 /* 178 * We are generating clock pulses. ndelay() determines durating of clk pulses. 179 * We will generate clock with rate 100 KHz and so duration of both clock levels 180 * is: delay in ns = (10^6 / 100) / 2 181 */ 182 #define RECOVERY_NDELAY 5000 183 #define RECOVERY_CLK_CNT 9 184 185 int i2c_generic_scl_recovery(struct i2c_adapter *adap) 186 { 187 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 188 int i = 0, scl = 1, ret; 189 190 if (bri->prepare_recovery) 191 bri->prepare_recovery(adap); 192 193 /* 194 * If we can set SDA, we will always create a STOP to ensure additional 195 * pulses will do no harm. This is achieved by letting SDA follow SCL 196 * half a cycle later. Check the 'incomplete_write_byte' fault injector 197 * for details. 198 */ 199 bri->set_scl(adap, scl); 200 ndelay(RECOVERY_NDELAY / 2); 201 if (bri->set_sda) 202 bri->set_sda(adap, scl); 203 ndelay(RECOVERY_NDELAY / 2); 204 205 /* 206 * By this time SCL is high, as we need to give 9 falling-rising edges 207 */ 208 while (i++ < RECOVERY_CLK_CNT * 2) { 209 if (scl) { 210 /* SCL shouldn't be low here */ 211 if (!bri->get_scl(adap)) { 212 dev_err(&adap->dev, 213 "SCL is stuck low, exit recovery\n"); 214 ret = -EBUSY; 215 break; 216 } 217 } 218 219 scl = !scl; 220 bri->set_scl(adap, scl); 221 /* Creating STOP again, see above */ 222 ndelay(RECOVERY_NDELAY / 2); 223 if (bri->set_sda) 224 bri->set_sda(adap, scl); 225 ndelay(RECOVERY_NDELAY / 2); 226 227 if (scl) { 228 ret = i2c_generic_bus_free(adap); 229 if (ret == 0) 230 break; 231 } 232 } 233 234 /* If we can't check bus status, assume recovery worked */ 235 if (ret == -EOPNOTSUPP) 236 ret = 0; 237 238 if (bri->unprepare_recovery) 239 bri->unprepare_recovery(adap); 240 241 return ret; 242 } 243 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery); 244 245 int i2c_recover_bus(struct i2c_adapter *adap) 246 { 247 if (!adap->bus_recovery_info) 248 return -EOPNOTSUPP; 249 250 dev_dbg(&adap->dev, "Trying i2c bus recovery\n"); 251 return adap->bus_recovery_info->recover_bus(adap); 252 } 253 EXPORT_SYMBOL_GPL(i2c_recover_bus); 254 255 static void i2c_init_recovery(struct i2c_adapter *adap) 256 { 257 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 258 char *err_str; 259 260 if (!bri) 261 return; 262 263 if (!bri->recover_bus) { 264 err_str = "no recover_bus() found"; 265 goto err; 266 } 267 268 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) { 269 bri->get_scl = get_scl_gpio_value; 270 bri->set_scl = set_scl_gpio_value; 271 if (bri->sda_gpiod) { 272 bri->get_sda = get_sda_gpio_value; 273 /* FIXME: add proper flag instead of '0' once available */ 274 if (gpiod_get_direction(bri->sda_gpiod) == 0) 275 bri->set_sda = set_sda_gpio_value; 276 } 277 return; 278 } 279 280 if (bri->recover_bus == i2c_generic_scl_recovery) { 281 /* Generic SCL recovery */ 282 if (!bri->set_scl || !bri->get_scl) { 283 err_str = "no {get|set}_scl() found"; 284 goto err; 285 } 286 if (!bri->set_sda && !bri->get_sda) { 287 err_str = "either get_sda() or set_sda() needed"; 288 goto err; 289 } 290 } 291 292 return; 293 err: 294 dev_err(&adap->dev, "Not using recovery: %s\n", err_str); 295 adap->bus_recovery_info = NULL; 296 } 297 298 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client) 299 { 300 struct i2c_adapter *adap = client->adapter; 301 unsigned int irq; 302 303 if (!adap->host_notify_domain) 304 return -ENXIO; 305 306 if (client->flags & I2C_CLIENT_TEN) 307 return -EINVAL; 308 309 irq = irq_find_mapping(adap->host_notify_domain, client->addr); 310 if (!irq) 311 irq = irq_create_mapping(adap->host_notify_domain, 312 client->addr); 313 314 return irq > 0 ? irq : -ENXIO; 315 } 316 317 static int i2c_device_probe(struct device *dev) 318 { 319 struct i2c_client *client = i2c_verify_client(dev); 320 struct i2c_driver *driver; 321 int status; 322 323 if (!client) 324 return 0; 325 326 driver = to_i2c_driver(dev->driver); 327 328 if (!client->irq && !driver->disable_i2c_core_irq_mapping) { 329 int irq = -ENOENT; 330 331 if (client->flags & I2C_CLIENT_HOST_NOTIFY) { 332 dev_dbg(dev, "Using Host Notify IRQ\n"); 333 irq = i2c_smbus_host_notify_to_irq(client); 334 } else if (dev->of_node) { 335 irq = of_irq_get_byname(dev->of_node, "irq"); 336 if (irq == -EINVAL || irq == -ENODATA) 337 irq = of_irq_get(dev->of_node, 0); 338 } else if (ACPI_COMPANION(dev)) { 339 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0); 340 } 341 if (irq == -EPROBE_DEFER) 342 return irq; 343 344 if (irq < 0) 345 irq = 0; 346 347 client->irq = irq; 348 } 349 350 /* 351 * An I2C ID table is not mandatory, if and only if, a suitable OF 352 * or ACPI ID table is supplied for the probing device. 353 */ 354 if (!driver->id_table && 355 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) && 356 !i2c_of_match_device(dev->driver->of_match_table, client)) 357 return -ENODEV; 358 359 if (client->flags & I2C_CLIENT_WAKE) { 360 int wakeirq = -ENOENT; 361 362 if (dev->of_node) { 363 wakeirq = of_irq_get_byname(dev->of_node, "wakeup"); 364 if (wakeirq == -EPROBE_DEFER) 365 return wakeirq; 366 } 367 368 device_init_wakeup(&client->dev, true); 369 370 if (wakeirq > 0 && wakeirq != client->irq) 371 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq); 372 else if (client->irq > 0) 373 status = dev_pm_set_wake_irq(dev, client->irq); 374 else 375 status = 0; 376 377 if (status) 378 dev_warn(&client->dev, "failed to set up wakeup irq\n"); 379 } 380 381 dev_dbg(dev, "probe\n"); 382 383 status = of_clk_set_defaults(dev->of_node, false); 384 if (status < 0) 385 goto err_clear_wakeup_irq; 386 387 status = dev_pm_domain_attach(&client->dev, true); 388 if (status) 389 goto err_clear_wakeup_irq; 390 391 /* 392 * When there are no more users of probe(), 393 * rename probe_new to probe. 394 */ 395 if (driver->probe_new) 396 status = driver->probe_new(client); 397 else if (driver->probe) 398 status = driver->probe(client, 399 i2c_match_id(driver->id_table, client)); 400 else 401 status = -EINVAL; 402 403 if (status) 404 goto err_detach_pm_domain; 405 406 return 0; 407 408 err_detach_pm_domain: 409 dev_pm_domain_detach(&client->dev, true); 410 err_clear_wakeup_irq: 411 dev_pm_clear_wake_irq(&client->dev); 412 device_init_wakeup(&client->dev, false); 413 return status; 414 } 415 416 static int i2c_device_remove(struct device *dev) 417 { 418 struct i2c_client *client = i2c_verify_client(dev); 419 struct i2c_driver *driver; 420 int status = 0; 421 422 if (!client || !dev->driver) 423 return 0; 424 425 driver = to_i2c_driver(dev->driver); 426 if (driver->remove) { 427 dev_dbg(dev, "remove\n"); 428 status = driver->remove(client); 429 } 430 431 dev_pm_domain_detach(&client->dev, true); 432 433 dev_pm_clear_wake_irq(&client->dev); 434 device_init_wakeup(&client->dev, false); 435 436 return status; 437 } 438 439 static void i2c_device_shutdown(struct device *dev) 440 { 441 struct i2c_client *client = i2c_verify_client(dev); 442 struct i2c_driver *driver; 443 444 if (!client || !dev->driver) 445 return; 446 driver = to_i2c_driver(dev->driver); 447 if (driver->shutdown) 448 driver->shutdown(client); 449 } 450 451 static void i2c_client_dev_release(struct device *dev) 452 { 453 kfree(to_i2c_client(dev)); 454 } 455 456 static ssize_t 457 show_name(struct device *dev, struct device_attribute *attr, char *buf) 458 { 459 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? 460 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); 461 } 462 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 463 464 static ssize_t 465 show_modalias(struct device *dev, struct device_attribute *attr, char *buf) 466 { 467 struct i2c_client *client = to_i2c_client(dev); 468 int len; 469 470 len = of_device_modalias(dev, buf, PAGE_SIZE); 471 if (len != -ENODEV) 472 return len; 473 474 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1); 475 if (len != -ENODEV) 476 return len; 477 478 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); 479 } 480 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL); 481 482 static struct attribute *i2c_dev_attrs[] = { 483 &dev_attr_name.attr, 484 /* modalias helps coldplug: modprobe $(cat .../modalias) */ 485 &dev_attr_modalias.attr, 486 NULL 487 }; 488 ATTRIBUTE_GROUPS(i2c_dev); 489 490 struct bus_type i2c_bus_type = { 491 .name = "i2c", 492 .match = i2c_device_match, 493 .probe = i2c_device_probe, 494 .remove = i2c_device_remove, 495 .shutdown = i2c_device_shutdown, 496 }; 497 EXPORT_SYMBOL_GPL(i2c_bus_type); 498 499 struct device_type i2c_client_type = { 500 .groups = i2c_dev_groups, 501 .uevent = i2c_device_uevent, 502 .release = i2c_client_dev_release, 503 }; 504 EXPORT_SYMBOL_GPL(i2c_client_type); 505 506 507 /** 508 * i2c_verify_client - return parameter as i2c_client, or NULL 509 * @dev: device, probably from some driver model iterator 510 * 511 * When traversing the driver model tree, perhaps using driver model 512 * iterators like @device_for_each_child(), you can't assume very much 513 * about the nodes you find. Use this function to avoid oopses caused 514 * by wrongly treating some non-I2C device as an i2c_client. 515 */ 516 struct i2c_client *i2c_verify_client(struct device *dev) 517 { 518 return (dev->type == &i2c_client_type) 519 ? to_i2c_client(dev) 520 : NULL; 521 } 522 EXPORT_SYMBOL(i2c_verify_client); 523 524 525 /* Return a unique address which takes the flags of the client into account */ 526 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client) 527 { 528 unsigned short addr = client->addr; 529 530 /* For some client flags, add an arbitrary offset to avoid collisions */ 531 if (client->flags & I2C_CLIENT_TEN) 532 addr |= I2C_ADDR_OFFSET_TEN_BIT; 533 534 if (client->flags & I2C_CLIENT_SLAVE) 535 addr |= I2C_ADDR_OFFSET_SLAVE; 536 537 return addr; 538 } 539 540 /* This is a permissive address validity check, I2C address map constraints 541 * are purposely not enforced, except for the general call address. */ 542 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags) 543 { 544 if (flags & I2C_CLIENT_TEN) { 545 /* 10-bit address, all values are valid */ 546 if (addr > 0x3ff) 547 return -EINVAL; 548 } else { 549 /* 7-bit address, reject the general call address */ 550 if (addr == 0x00 || addr > 0x7f) 551 return -EINVAL; 552 } 553 return 0; 554 } 555 556 /* And this is a strict address validity check, used when probing. If a 557 * device uses a reserved address, then it shouldn't be probed. 7-bit 558 * addressing is assumed, 10-bit address devices are rare and should be 559 * explicitly enumerated. */ 560 int i2c_check_7bit_addr_validity_strict(unsigned short addr) 561 { 562 /* 563 * Reserved addresses per I2C specification: 564 * 0x00 General call address / START byte 565 * 0x01 CBUS address 566 * 0x02 Reserved for different bus format 567 * 0x03 Reserved for future purposes 568 * 0x04-0x07 Hs-mode master code 569 * 0x78-0x7b 10-bit slave addressing 570 * 0x7c-0x7f Reserved for future purposes 571 */ 572 if (addr < 0x08 || addr > 0x77) 573 return -EINVAL; 574 return 0; 575 } 576 577 static int __i2c_check_addr_busy(struct device *dev, void *addrp) 578 { 579 struct i2c_client *client = i2c_verify_client(dev); 580 int addr = *(int *)addrp; 581 582 if (client && i2c_encode_flags_to_addr(client) == addr) 583 return -EBUSY; 584 return 0; 585 } 586 587 /* walk up mux tree */ 588 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) 589 { 590 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 591 int result; 592 593 result = device_for_each_child(&adapter->dev, &addr, 594 __i2c_check_addr_busy); 595 596 if (!result && parent) 597 result = i2c_check_mux_parents(parent, addr); 598 599 return result; 600 } 601 602 /* recurse down mux tree */ 603 static int i2c_check_mux_children(struct device *dev, void *addrp) 604 { 605 int result; 606 607 if (dev->type == &i2c_adapter_type) 608 result = device_for_each_child(dev, addrp, 609 i2c_check_mux_children); 610 else 611 result = __i2c_check_addr_busy(dev, addrp); 612 613 return result; 614 } 615 616 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) 617 { 618 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 619 int result = 0; 620 621 if (parent) 622 result = i2c_check_mux_parents(parent, addr); 623 624 if (!result) 625 result = device_for_each_child(&adapter->dev, &addr, 626 i2c_check_mux_children); 627 628 return result; 629 } 630 631 /** 632 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment 633 * @adapter: Target I2C bus segment 634 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT 635 * locks only this branch in the adapter tree 636 */ 637 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, 638 unsigned int flags) 639 { 640 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); 641 } 642 643 /** 644 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment 645 * @adapter: Target I2C bus segment 646 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT 647 * trylocks only this branch in the adapter tree 648 */ 649 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, 650 unsigned int flags) 651 { 652 return rt_mutex_trylock(&adapter->bus_lock); 653 } 654 655 /** 656 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment 657 * @adapter: Target I2C bus segment 658 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT 659 * unlocks only this branch in the adapter tree 660 */ 661 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, 662 unsigned int flags) 663 { 664 rt_mutex_unlock(&adapter->bus_lock); 665 } 666 667 static void i2c_dev_set_name(struct i2c_adapter *adap, 668 struct i2c_client *client, 669 struct i2c_board_info const *info) 670 { 671 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 672 673 if (info && info->dev_name) { 674 dev_set_name(&client->dev, "i2c-%s", info->dev_name); 675 return; 676 } 677 678 if (adev) { 679 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev)); 680 return; 681 } 682 683 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), 684 i2c_encode_flags_to_addr(client)); 685 } 686 687 static int i2c_dev_irq_from_resources(const struct resource *resources, 688 unsigned int num_resources) 689 { 690 struct irq_data *irqd; 691 int i; 692 693 for (i = 0; i < num_resources; i++) { 694 const struct resource *r = &resources[i]; 695 696 if (resource_type(r) != IORESOURCE_IRQ) 697 continue; 698 699 if (r->flags & IORESOURCE_BITS) { 700 irqd = irq_get_irq_data(r->start); 701 if (!irqd) 702 break; 703 704 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); 705 } 706 707 return r->start; 708 } 709 710 return 0; 711 } 712 713 /** 714 * i2c_new_device - instantiate an i2c device 715 * @adap: the adapter managing the device 716 * @info: describes one I2C device; bus_num is ignored 717 * Context: can sleep 718 * 719 * Create an i2c device. Binding is handled through driver model 720 * probe()/remove() methods. A driver may be bound to this device when we 721 * return from this function, or any later moment (e.g. maybe hotplugging will 722 * load the driver module). This call is not appropriate for use by mainboard 723 * initialization logic, which usually runs during an arch_initcall() long 724 * before any i2c_adapter could exist. 725 * 726 * This returns the new i2c client, which may be saved for later use with 727 * i2c_unregister_device(); or NULL to indicate an error. 728 */ 729 struct i2c_client * 730 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info) 731 { 732 struct i2c_client *client; 733 int status; 734 735 client = kzalloc(sizeof *client, GFP_KERNEL); 736 if (!client) 737 return NULL; 738 739 client->adapter = adap; 740 741 client->dev.platform_data = info->platform_data; 742 client->flags = info->flags; 743 client->addr = info->addr; 744 745 client->irq = info->irq; 746 if (!client->irq) 747 client->irq = i2c_dev_irq_from_resources(info->resources, 748 info->num_resources); 749 750 strlcpy(client->name, info->type, sizeof(client->name)); 751 752 status = i2c_check_addr_validity(client->addr, client->flags); 753 if (status) { 754 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", 755 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); 756 goto out_err_silent; 757 } 758 759 /* Check for address business */ 760 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); 761 if (status) 762 goto out_err; 763 764 client->dev.parent = &client->adapter->dev; 765 client->dev.bus = &i2c_bus_type; 766 client->dev.type = &i2c_client_type; 767 client->dev.of_node = of_node_get(info->of_node); 768 client->dev.fwnode = info->fwnode; 769 770 i2c_dev_set_name(adap, client, info); 771 772 if (info->properties) { 773 status = device_add_properties(&client->dev, info->properties); 774 if (status) { 775 dev_err(&adap->dev, 776 "Failed to add properties to client %s: %d\n", 777 client->name, status); 778 goto out_err_put_of_node; 779 } 780 } 781 782 status = device_register(&client->dev); 783 if (status) 784 goto out_free_props; 785 786 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", 787 client->name, dev_name(&client->dev)); 788 789 return client; 790 791 out_free_props: 792 if (info->properties) 793 device_remove_properties(&client->dev); 794 out_err_put_of_node: 795 of_node_put(info->of_node); 796 out_err: 797 dev_err(&adap->dev, 798 "Failed to register i2c client %s at 0x%02x (%d)\n", 799 client->name, client->addr, status); 800 out_err_silent: 801 kfree(client); 802 return NULL; 803 } 804 EXPORT_SYMBOL_GPL(i2c_new_device); 805 806 807 /** 808 * i2c_unregister_device - reverse effect of i2c_new_device() 809 * @client: value returned from i2c_new_device() 810 * Context: can sleep 811 */ 812 void i2c_unregister_device(struct i2c_client *client) 813 { 814 if (!client) 815 return; 816 817 if (client->dev.of_node) { 818 of_node_clear_flag(client->dev.of_node, OF_POPULATED); 819 of_node_put(client->dev.of_node); 820 } 821 822 if (ACPI_COMPANION(&client->dev)) 823 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev)); 824 device_unregister(&client->dev); 825 } 826 EXPORT_SYMBOL_GPL(i2c_unregister_device); 827 828 829 static const struct i2c_device_id dummy_id[] = { 830 { "dummy", 0 }, 831 { }, 832 }; 833 834 static int dummy_probe(struct i2c_client *client, 835 const struct i2c_device_id *id) 836 { 837 return 0; 838 } 839 840 static int dummy_remove(struct i2c_client *client) 841 { 842 return 0; 843 } 844 845 static struct i2c_driver dummy_driver = { 846 .driver.name = "dummy", 847 .probe = dummy_probe, 848 .remove = dummy_remove, 849 .id_table = dummy_id, 850 }; 851 852 /** 853 * i2c_new_dummy - return a new i2c device bound to a dummy driver 854 * @adapter: the adapter managing the device 855 * @address: seven bit address to be used 856 * Context: can sleep 857 * 858 * This returns an I2C client bound to the "dummy" driver, intended for use 859 * with devices that consume multiple addresses. Examples of such chips 860 * include various EEPROMS (like 24c04 and 24c08 models). 861 * 862 * These dummy devices have two main uses. First, most I2C and SMBus calls 863 * except i2c_transfer() need a client handle; the dummy will be that handle. 864 * And second, this prevents the specified address from being bound to a 865 * different driver. 866 * 867 * This returns the new i2c client, which should be saved for later use with 868 * i2c_unregister_device(); or NULL to indicate an error. 869 */ 870 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address) 871 { 872 struct i2c_board_info info = { 873 I2C_BOARD_INFO("dummy", address), 874 }; 875 876 return i2c_new_device(adapter, &info); 877 } 878 EXPORT_SYMBOL_GPL(i2c_new_dummy); 879 880 /** 881 * i2c_new_secondary_device - Helper to get the instantiated secondary address 882 * and create the associated device 883 * @client: Handle to the primary client 884 * @name: Handle to specify which secondary address to get 885 * @default_addr: Used as a fallback if no secondary address was specified 886 * Context: can sleep 887 * 888 * I2C clients can be composed of multiple I2C slaves bound together in a single 889 * component. The I2C client driver then binds to the master I2C slave and needs 890 * to create I2C dummy clients to communicate with all the other slaves. 891 * 892 * This function creates and returns an I2C dummy client whose I2C address is 893 * retrieved from the platform firmware based on the given slave name. If no 894 * address is specified by the firmware default_addr is used. 895 * 896 * On DT-based platforms the address is retrieved from the "reg" property entry 897 * cell whose "reg-names" value matches the slave name. 898 * 899 * This returns the new i2c client, which should be saved for later use with 900 * i2c_unregister_device(); or NULL to indicate an error. 901 */ 902 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client, 903 const char *name, 904 u16 default_addr) 905 { 906 struct device_node *np = client->dev.of_node; 907 u32 addr = default_addr; 908 int i; 909 910 if (np) { 911 i = of_property_match_string(np, "reg-names", name); 912 if (i >= 0) 913 of_property_read_u32_index(np, "reg", i, &addr); 914 } 915 916 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); 917 return i2c_new_dummy(client->adapter, addr); 918 } 919 EXPORT_SYMBOL_GPL(i2c_new_secondary_device); 920 921 /* ------------------------------------------------------------------------- */ 922 923 /* I2C bus adapters -- one roots each I2C or SMBUS segment */ 924 925 static void i2c_adapter_dev_release(struct device *dev) 926 { 927 struct i2c_adapter *adap = to_i2c_adapter(dev); 928 complete(&adap->dev_released); 929 } 930 931 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) 932 { 933 unsigned int depth = 0; 934 935 while ((adapter = i2c_parent_is_i2c_adapter(adapter))) 936 depth++; 937 938 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES, 939 "adapter depth exceeds lockdep subclass limit\n"); 940 941 return depth; 942 } 943 EXPORT_SYMBOL_GPL(i2c_adapter_depth); 944 945 /* 946 * Let users instantiate I2C devices through sysfs. This can be used when 947 * platform initialization code doesn't contain the proper data for 948 * whatever reason. Also useful for drivers that do device detection and 949 * detection fails, either because the device uses an unexpected address, 950 * or this is a compatible device with different ID register values. 951 * 952 * Parameter checking may look overzealous, but we really don't want 953 * the user to provide incorrect parameters. 954 */ 955 static ssize_t 956 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr, 957 const char *buf, size_t count) 958 { 959 struct i2c_adapter *adap = to_i2c_adapter(dev); 960 struct i2c_board_info info; 961 struct i2c_client *client; 962 char *blank, end; 963 int res; 964 965 memset(&info, 0, sizeof(struct i2c_board_info)); 966 967 blank = strchr(buf, ' '); 968 if (!blank) { 969 dev_err(dev, "%s: Missing parameters\n", "new_device"); 970 return -EINVAL; 971 } 972 if (blank - buf > I2C_NAME_SIZE - 1) { 973 dev_err(dev, "%s: Invalid device name\n", "new_device"); 974 return -EINVAL; 975 } 976 memcpy(info.type, buf, blank - buf); 977 978 /* Parse remaining parameters, reject extra parameters */ 979 res = sscanf(++blank, "%hi%c", &info.addr, &end); 980 if (res < 1) { 981 dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); 982 return -EINVAL; 983 } 984 if (res > 1 && end != '\n') { 985 dev_err(dev, "%s: Extra parameters\n", "new_device"); 986 return -EINVAL; 987 } 988 989 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) { 990 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT; 991 info.flags |= I2C_CLIENT_TEN; 992 } 993 994 if (info.addr & I2C_ADDR_OFFSET_SLAVE) { 995 info.addr &= ~I2C_ADDR_OFFSET_SLAVE; 996 info.flags |= I2C_CLIENT_SLAVE; 997 } 998 999 client = i2c_new_device(adap, &info); 1000 if (!client) 1001 return -EINVAL; 1002 1003 /* Keep track of the added device */ 1004 mutex_lock(&adap->userspace_clients_lock); 1005 list_add_tail(&client->detected, &adap->userspace_clients); 1006 mutex_unlock(&adap->userspace_clients_lock); 1007 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", 1008 info.type, info.addr); 1009 1010 return count; 1011 } 1012 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device); 1013 1014 /* 1015 * And of course let the users delete the devices they instantiated, if 1016 * they got it wrong. This interface can only be used to delete devices 1017 * instantiated by i2c_sysfs_new_device above. This guarantees that we 1018 * don't delete devices to which some kernel code still has references. 1019 * 1020 * Parameter checking may look overzealous, but we really don't want 1021 * the user to delete the wrong device. 1022 */ 1023 static ssize_t 1024 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr, 1025 const char *buf, size_t count) 1026 { 1027 struct i2c_adapter *adap = to_i2c_adapter(dev); 1028 struct i2c_client *client, *next; 1029 unsigned short addr; 1030 char end; 1031 int res; 1032 1033 /* Parse parameters, reject extra parameters */ 1034 res = sscanf(buf, "%hi%c", &addr, &end); 1035 if (res < 1) { 1036 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); 1037 return -EINVAL; 1038 } 1039 if (res > 1 && end != '\n') { 1040 dev_err(dev, "%s: Extra parameters\n", "delete_device"); 1041 return -EINVAL; 1042 } 1043 1044 /* Make sure the device was added through sysfs */ 1045 res = -ENOENT; 1046 mutex_lock_nested(&adap->userspace_clients_lock, 1047 i2c_adapter_depth(adap)); 1048 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1049 detected) { 1050 if (i2c_encode_flags_to_addr(client) == addr) { 1051 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", 1052 "delete_device", client->name, client->addr); 1053 1054 list_del(&client->detected); 1055 i2c_unregister_device(client); 1056 res = count; 1057 break; 1058 } 1059 } 1060 mutex_unlock(&adap->userspace_clients_lock); 1061 1062 if (res < 0) 1063 dev_err(dev, "%s: Can't find device in list\n", 1064 "delete_device"); 1065 return res; 1066 } 1067 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL, 1068 i2c_sysfs_delete_device); 1069 1070 static struct attribute *i2c_adapter_attrs[] = { 1071 &dev_attr_name.attr, 1072 &dev_attr_new_device.attr, 1073 &dev_attr_delete_device.attr, 1074 NULL 1075 }; 1076 ATTRIBUTE_GROUPS(i2c_adapter); 1077 1078 struct device_type i2c_adapter_type = { 1079 .groups = i2c_adapter_groups, 1080 .release = i2c_adapter_dev_release, 1081 }; 1082 EXPORT_SYMBOL_GPL(i2c_adapter_type); 1083 1084 /** 1085 * i2c_verify_adapter - return parameter as i2c_adapter or NULL 1086 * @dev: device, probably from some driver model iterator 1087 * 1088 * When traversing the driver model tree, perhaps using driver model 1089 * iterators like @device_for_each_child(), you can't assume very much 1090 * about the nodes you find. Use this function to avoid oopses caused 1091 * by wrongly treating some non-I2C device as an i2c_adapter. 1092 */ 1093 struct i2c_adapter *i2c_verify_adapter(struct device *dev) 1094 { 1095 return (dev->type == &i2c_adapter_type) 1096 ? to_i2c_adapter(dev) 1097 : NULL; 1098 } 1099 EXPORT_SYMBOL(i2c_verify_adapter); 1100 1101 #ifdef CONFIG_I2C_COMPAT 1102 static struct class_compat *i2c_adapter_compat_class; 1103 #endif 1104 1105 static void i2c_scan_static_board_info(struct i2c_adapter *adapter) 1106 { 1107 struct i2c_devinfo *devinfo; 1108 1109 down_read(&__i2c_board_lock); 1110 list_for_each_entry(devinfo, &__i2c_board_list, list) { 1111 if (devinfo->busnum == adapter->nr 1112 && !i2c_new_device(adapter, 1113 &devinfo->board_info)) 1114 dev_err(&adapter->dev, 1115 "Can't create device at 0x%02x\n", 1116 devinfo->board_info.addr); 1117 } 1118 up_read(&__i2c_board_lock); 1119 } 1120 1121 static int i2c_do_add_adapter(struct i2c_driver *driver, 1122 struct i2c_adapter *adap) 1123 { 1124 /* Detect supported devices on that bus, and instantiate them */ 1125 i2c_detect(adap, driver); 1126 1127 return 0; 1128 } 1129 1130 static int __process_new_adapter(struct device_driver *d, void *data) 1131 { 1132 return i2c_do_add_adapter(to_i2c_driver(d), data); 1133 } 1134 1135 static const struct i2c_lock_operations i2c_adapter_lock_ops = { 1136 .lock_bus = i2c_adapter_lock_bus, 1137 .trylock_bus = i2c_adapter_trylock_bus, 1138 .unlock_bus = i2c_adapter_unlock_bus, 1139 }; 1140 1141 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap) 1142 { 1143 struct irq_domain *domain = adap->host_notify_domain; 1144 irq_hw_number_t hwirq; 1145 1146 if (!domain) 1147 return; 1148 1149 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++) 1150 irq_dispose_mapping(irq_find_mapping(domain, hwirq)); 1151 1152 irq_domain_remove(domain); 1153 adap->host_notify_domain = NULL; 1154 } 1155 1156 static int i2c_host_notify_irq_map(struct irq_domain *h, 1157 unsigned int virq, 1158 irq_hw_number_t hw_irq_num) 1159 { 1160 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq); 1161 1162 return 0; 1163 } 1164 1165 static const struct irq_domain_ops i2c_host_notify_irq_ops = { 1166 .map = i2c_host_notify_irq_map, 1167 }; 1168 1169 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap) 1170 { 1171 struct irq_domain *domain; 1172 1173 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY)) 1174 return 0; 1175 1176 domain = irq_domain_create_linear(adap->dev.fwnode, 1177 I2C_ADDR_7BITS_COUNT, 1178 &i2c_host_notify_irq_ops, adap); 1179 if (!domain) 1180 return -ENOMEM; 1181 1182 adap->host_notify_domain = domain; 1183 1184 return 0; 1185 } 1186 1187 /** 1188 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct 1189 * I2C client. 1190 * @adap: the adapter 1191 * @addr: the I2C address of the notifying device 1192 * Context: can't sleep 1193 * 1194 * Helper function to be called from an I2C bus driver's interrupt 1195 * handler. It will schedule the Host Notify IRQ. 1196 */ 1197 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr) 1198 { 1199 int irq; 1200 1201 if (!adap) 1202 return -EINVAL; 1203 1204 irq = irq_find_mapping(adap->host_notify_domain, addr); 1205 if (irq <= 0) 1206 return -ENXIO; 1207 1208 generic_handle_irq(irq); 1209 1210 return 0; 1211 } 1212 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify); 1213 1214 static int i2c_register_adapter(struct i2c_adapter *adap) 1215 { 1216 int res = -EINVAL; 1217 1218 /* Can't register until after driver model init */ 1219 if (WARN_ON(!is_registered)) { 1220 res = -EAGAIN; 1221 goto out_list; 1222 } 1223 1224 /* Sanity checks */ 1225 if (WARN(!adap->name[0], "i2c adapter has no name")) 1226 goto out_list; 1227 1228 if (!adap->algo) { 1229 pr_err("adapter '%s': no algo supplied!\n", adap->name); 1230 goto out_list; 1231 } 1232 1233 if (!adap->lock_ops) 1234 adap->lock_ops = &i2c_adapter_lock_ops; 1235 1236 rt_mutex_init(&adap->bus_lock); 1237 rt_mutex_init(&adap->mux_lock); 1238 mutex_init(&adap->userspace_clients_lock); 1239 INIT_LIST_HEAD(&adap->userspace_clients); 1240 1241 /* Set default timeout to 1 second if not already set */ 1242 if (adap->timeout == 0) 1243 adap->timeout = HZ; 1244 1245 /* register soft irqs for Host Notify */ 1246 res = i2c_setup_host_notify_irq_domain(adap); 1247 if (res) { 1248 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n", 1249 adap->name, res); 1250 goto out_list; 1251 } 1252 1253 dev_set_name(&adap->dev, "i2c-%d", adap->nr); 1254 adap->dev.bus = &i2c_bus_type; 1255 adap->dev.type = &i2c_adapter_type; 1256 res = device_register(&adap->dev); 1257 if (res) { 1258 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); 1259 goto out_list; 1260 } 1261 1262 res = of_i2c_setup_smbus_alert(adap); 1263 if (res) 1264 goto out_reg; 1265 1266 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); 1267 1268 pm_runtime_no_callbacks(&adap->dev); 1269 pm_suspend_ignore_children(&adap->dev, true); 1270 pm_runtime_enable(&adap->dev); 1271 1272 #ifdef CONFIG_I2C_COMPAT 1273 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, 1274 adap->dev.parent); 1275 if (res) 1276 dev_warn(&adap->dev, 1277 "Failed to create compatibility class link\n"); 1278 #endif 1279 1280 i2c_init_recovery(adap); 1281 1282 /* create pre-declared device nodes */ 1283 of_i2c_register_devices(adap); 1284 i2c_acpi_register_devices(adap); 1285 i2c_acpi_install_space_handler(adap); 1286 1287 if (adap->nr < __i2c_first_dynamic_bus_num) 1288 i2c_scan_static_board_info(adap); 1289 1290 /* Notify drivers */ 1291 mutex_lock(&core_lock); 1292 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); 1293 mutex_unlock(&core_lock); 1294 1295 return 0; 1296 1297 out_reg: 1298 init_completion(&adap->dev_released); 1299 device_unregister(&adap->dev); 1300 wait_for_completion(&adap->dev_released); 1301 out_list: 1302 mutex_lock(&core_lock); 1303 idr_remove(&i2c_adapter_idr, adap->nr); 1304 mutex_unlock(&core_lock); 1305 return res; 1306 } 1307 1308 /** 1309 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 1310 * @adap: the adapter to register (with adap->nr initialized) 1311 * Context: can sleep 1312 * 1313 * See i2c_add_numbered_adapter() for details. 1314 */ 1315 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) 1316 { 1317 int id; 1318 1319 mutex_lock(&core_lock); 1320 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); 1321 mutex_unlock(&core_lock); 1322 if (WARN(id < 0, "couldn't get idr")) 1323 return id == -ENOSPC ? -EBUSY : id; 1324 1325 return i2c_register_adapter(adap); 1326 } 1327 1328 /** 1329 * i2c_add_adapter - declare i2c adapter, use dynamic bus number 1330 * @adapter: the adapter to add 1331 * Context: can sleep 1332 * 1333 * This routine is used to declare an I2C adapter when its bus number 1334 * doesn't matter or when its bus number is specified by an dt alias. 1335 * Examples of bases when the bus number doesn't matter: I2C adapters 1336 * dynamically added by USB links or PCI plugin cards. 1337 * 1338 * When this returns zero, a new bus number was allocated and stored 1339 * in adap->nr, and the specified adapter became available for clients. 1340 * Otherwise, a negative errno value is returned. 1341 */ 1342 int i2c_add_adapter(struct i2c_adapter *adapter) 1343 { 1344 struct device *dev = &adapter->dev; 1345 int id; 1346 1347 if (dev->of_node) { 1348 id = of_alias_get_id(dev->of_node, "i2c"); 1349 if (id >= 0) { 1350 adapter->nr = id; 1351 return __i2c_add_numbered_adapter(adapter); 1352 } 1353 } 1354 1355 mutex_lock(&core_lock); 1356 id = idr_alloc(&i2c_adapter_idr, adapter, 1357 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); 1358 mutex_unlock(&core_lock); 1359 if (WARN(id < 0, "couldn't get idr")) 1360 return id; 1361 1362 adapter->nr = id; 1363 1364 return i2c_register_adapter(adapter); 1365 } 1366 EXPORT_SYMBOL(i2c_add_adapter); 1367 1368 /** 1369 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number 1370 * @adap: the adapter to register (with adap->nr initialized) 1371 * Context: can sleep 1372 * 1373 * This routine is used to declare an I2C adapter when its bus number 1374 * matters. For example, use it for I2C adapters from system-on-chip CPUs, 1375 * or otherwise built in to the system's mainboard, and where i2c_board_info 1376 * is used to properly configure I2C devices. 1377 * 1378 * If the requested bus number is set to -1, then this function will behave 1379 * identically to i2c_add_adapter, and will dynamically assign a bus number. 1380 * 1381 * If no devices have pre-been declared for this bus, then be sure to 1382 * register the adapter before any dynamically allocated ones. Otherwise 1383 * the required bus ID may not be available. 1384 * 1385 * When this returns zero, the specified adapter became available for 1386 * clients using the bus number provided in adap->nr. Also, the table 1387 * of I2C devices pre-declared using i2c_register_board_info() is scanned, 1388 * and the appropriate driver model device nodes are created. Otherwise, a 1389 * negative errno value is returned. 1390 */ 1391 int i2c_add_numbered_adapter(struct i2c_adapter *adap) 1392 { 1393 if (adap->nr == -1) /* -1 means dynamically assign bus id */ 1394 return i2c_add_adapter(adap); 1395 1396 return __i2c_add_numbered_adapter(adap); 1397 } 1398 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); 1399 1400 static void i2c_do_del_adapter(struct i2c_driver *driver, 1401 struct i2c_adapter *adapter) 1402 { 1403 struct i2c_client *client, *_n; 1404 1405 /* Remove the devices we created ourselves as the result of hardware 1406 * probing (using a driver's detect method) */ 1407 list_for_each_entry_safe(client, _n, &driver->clients, detected) { 1408 if (client->adapter == adapter) { 1409 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", 1410 client->name, client->addr); 1411 list_del(&client->detected); 1412 i2c_unregister_device(client); 1413 } 1414 } 1415 } 1416 1417 static int __unregister_client(struct device *dev, void *dummy) 1418 { 1419 struct i2c_client *client = i2c_verify_client(dev); 1420 if (client && strcmp(client->name, "dummy")) 1421 i2c_unregister_device(client); 1422 return 0; 1423 } 1424 1425 static int __unregister_dummy(struct device *dev, void *dummy) 1426 { 1427 struct i2c_client *client = i2c_verify_client(dev); 1428 i2c_unregister_device(client); 1429 return 0; 1430 } 1431 1432 static int __process_removed_adapter(struct device_driver *d, void *data) 1433 { 1434 i2c_do_del_adapter(to_i2c_driver(d), data); 1435 return 0; 1436 } 1437 1438 /** 1439 * i2c_del_adapter - unregister I2C adapter 1440 * @adap: the adapter being unregistered 1441 * Context: can sleep 1442 * 1443 * This unregisters an I2C adapter which was previously registered 1444 * by @i2c_add_adapter or @i2c_add_numbered_adapter. 1445 */ 1446 void i2c_del_adapter(struct i2c_adapter *adap) 1447 { 1448 struct i2c_adapter *found; 1449 struct i2c_client *client, *next; 1450 1451 /* First make sure that this adapter was ever added */ 1452 mutex_lock(&core_lock); 1453 found = idr_find(&i2c_adapter_idr, adap->nr); 1454 mutex_unlock(&core_lock); 1455 if (found != adap) { 1456 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); 1457 return; 1458 } 1459 1460 i2c_acpi_remove_space_handler(adap); 1461 /* Tell drivers about this removal */ 1462 mutex_lock(&core_lock); 1463 bus_for_each_drv(&i2c_bus_type, NULL, adap, 1464 __process_removed_adapter); 1465 mutex_unlock(&core_lock); 1466 1467 /* Remove devices instantiated from sysfs */ 1468 mutex_lock_nested(&adap->userspace_clients_lock, 1469 i2c_adapter_depth(adap)); 1470 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1471 detected) { 1472 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, 1473 client->addr); 1474 list_del(&client->detected); 1475 i2c_unregister_device(client); 1476 } 1477 mutex_unlock(&adap->userspace_clients_lock); 1478 1479 /* Detach any active clients. This can't fail, thus we do not 1480 * check the returned value. This is a two-pass process, because 1481 * we can't remove the dummy devices during the first pass: they 1482 * could have been instantiated by real devices wishing to clean 1483 * them up properly, so we give them a chance to do that first. */ 1484 device_for_each_child(&adap->dev, NULL, __unregister_client); 1485 device_for_each_child(&adap->dev, NULL, __unregister_dummy); 1486 1487 #ifdef CONFIG_I2C_COMPAT 1488 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, 1489 adap->dev.parent); 1490 #endif 1491 1492 /* device name is gone after device_unregister */ 1493 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); 1494 1495 pm_runtime_disable(&adap->dev); 1496 1497 i2c_host_notify_irq_teardown(adap); 1498 1499 /* wait until all references to the device are gone 1500 * 1501 * FIXME: This is old code and should ideally be replaced by an 1502 * alternative which results in decoupling the lifetime of the struct 1503 * device from the i2c_adapter, like spi or netdev do. Any solution 1504 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled! 1505 */ 1506 init_completion(&adap->dev_released); 1507 device_unregister(&adap->dev); 1508 wait_for_completion(&adap->dev_released); 1509 1510 /* free bus id */ 1511 mutex_lock(&core_lock); 1512 idr_remove(&i2c_adapter_idr, adap->nr); 1513 mutex_unlock(&core_lock); 1514 1515 /* Clear the device structure in case this adapter is ever going to be 1516 added again */ 1517 memset(&adap->dev, 0, sizeof(adap->dev)); 1518 } 1519 EXPORT_SYMBOL(i2c_del_adapter); 1520 1521 /** 1522 * i2c_parse_fw_timings - get I2C related timing parameters from firmware 1523 * @dev: The device to scan for I2C timing properties 1524 * @t: the i2c_timings struct to be filled with values 1525 * @use_defaults: bool to use sane defaults derived from the I2C specification 1526 * when properties are not found, otherwise use 0 1527 * 1528 * Scan the device for the generic I2C properties describing timing parameters 1529 * for the signal and fill the given struct with the results. If a property was 1530 * not found and use_defaults was true, then maximum timings are assumed which 1531 * are derived from the I2C specification. If use_defaults is not used, the 1532 * results will be 0, so drivers can apply their own defaults later. The latter 1533 * is mainly intended for avoiding regressions of existing drivers which want 1534 * to switch to this function. New drivers almost always should use the defaults. 1535 */ 1536 1537 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) 1538 { 1539 int ret; 1540 1541 memset(t, 0, sizeof(*t)); 1542 1543 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz); 1544 if (ret && use_defaults) 1545 t->bus_freq_hz = 100000; 1546 1547 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns); 1548 if (ret && use_defaults) { 1549 if (t->bus_freq_hz <= 100000) 1550 t->scl_rise_ns = 1000; 1551 else if (t->bus_freq_hz <= 400000) 1552 t->scl_rise_ns = 300; 1553 else 1554 t->scl_rise_ns = 120; 1555 } 1556 1557 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns); 1558 if (ret && use_defaults) { 1559 if (t->bus_freq_hz <= 400000) 1560 t->scl_fall_ns = 300; 1561 else 1562 t->scl_fall_ns = 120; 1563 } 1564 1565 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns); 1566 1567 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns); 1568 if (ret && use_defaults) 1569 t->sda_fall_ns = t->scl_fall_ns; 1570 1571 device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns); 1572 } 1573 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); 1574 1575 /* ------------------------------------------------------------------------- */ 1576 1577 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *)) 1578 { 1579 int res; 1580 1581 mutex_lock(&core_lock); 1582 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn); 1583 mutex_unlock(&core_lock); 1584 1585 return res; 1586 } 1587 EXPORT_SYMBOL_GPL(i2c_for_each_dev); 1588 1589 static int __process_new_driver(struct device *dev, void *data) 1590 { 1591 if (dev->type != &i2c_adapter_type) 1592 return 0; 1593 return i2c_do_add_adapter(data, to_i2c_adapter(dev)); 1594 } 1595 1596 /* 1597 * An i2c_driver is used with one or more i2c_client (device) nodes to access 1598 * i2c slave chips, on a bus instance associated with some i2c_adapter. 1599 */ 1600 1601 int i2c_register_driver(struct module *owner, struct i2c_driver *driver) 1602 { 1603 int res; 1604 1605 /* Can't register until after driver model init */ 1606 if (WARN_ON(!is_registered)) 1607 return -EAGAIN; 1608 1609 /* add the driver to the list of i2c drivers in the driver core */ 1610 driver->driver.owner = owner; 1611 driver->driver.bus = &i2c_bus_type; 1612 INIT_LIST_HEAD(&driver->clients); 1613 1614 /* When registration returns, the driver core 1615 * will have called probe() for all matching-but-unbound devices. 1616 */ 1617 res = driver_register(&driver->driver); 1618 if (res) 1619 return res; 1620 1621 pr_debug("driver [%s] registered\n", driver->driver.name); 1622 1623 /* Walk the adapters that are already present */ 1624 i2c_for_each_dev(driver, __process_new_driver); 1625 1626 return 0; 1627 } 1628 EXPORT_SYMBOL(i2c_register_driver); 1629 1630 static int __process_removed_driver(struct device *dev, void *data) 1631 { 1632 if (dev->type == &i2c_adapter_type) 1633 i2c_do_del_adapter(data, to_i2c_adapter(dev)); 1634 return 0; 1635 } 1636 1637 /** 1638 * i2c_del_driver - unregister I2C driver 1639 * @driver: the driver being unregistered 1640 * Context: can sleep 1641 */ 1642 void i2c_del_driver(struct i2c_driver *driver) 1643 { 1644 i2c_for_each_dev(driver, __process_removed_driver); 1645 1646 driver_unregister(&driver->driver); 1647 pr_debug("driver [%s] unregistered\n", driver->driver.name); 1648 } 1649 EXPORT_SYMBOL(i2c_del_driver); 1650 1651 /* ------------------------------------------------------------------------- */ 1652 1653 /** 1654 * i2c_use_client - increments the reference count of the i2c client structure 1655 * @client: the client being referenced 1656 * 1657 * Each live reference to a client should be refcounted. The driver model does 1658 * that automatically as part of driver binding, so that most drivers don't 1659 * need to do this explicitly: they hold a reference until they're unbound 1660 * from the device. 1661 * 1662 * A pointer to the client with the incremented reference counter is returned. 1663 */ 1664 struct i2c_client *i2c_use_client(struct i2c_client *client) 1665 { 1666 if (client && get_device(&client->dev)) 1667 return client; 1668 return NULL; 1669 } 1670 EXPORT_SYMBOL(i2c_use_client); 1671 1672 /** 1673 * i2c_release_client - release a use of the i2c client structure 1674 * @client: the client being no longer referenced 1675 * 1676 * Must be called when a user of a client is finished with it. 1677 */ 1678 void i2c_release_client(struct i2c_client *client) 1679 { 1680 if (client) 1681 put_device(&client->dev); 1682 } 1683 EXPORT_SYMBOL(i2c_release_client); 1684 1685 struct i2c_cmd_arg { 1686 unsigned cmd; 1687 void *arg; 1688 }; 1689 1690 static int i2c_cmd(struct device *dev, void *_arg) 1691 { 1692 struct i2c_client *client = i2c_verify_client(dev); 1693 struct i2c_cmd_arg *arg = _arg; 1694 struct i2c_driver *driver; 1695 1696 if (!client || !client->dev.driver) 1697 return 0; 1698 1699 driver = to_i2c_driver(client->dev.driver); 1700 if (driver->command) 1701 driver->command(client, arg->cmd, arg->arg); 1702 return 0; 1703 } 1704 1705 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) 1706 { 1707 struct i2c_cmd_arg cmd_arg; 1708 1709 cmd_arg.cmd = cmd; 1710 cmd_arg.arg = arg; 1711 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); 1712 } 1713 EXPORT_SYMBOL(i2c_clients_command); 1714 1715 static int __init i2c_init(void) 1716 { 1717 int retval; 1718 1719 retval = of_alias_get_highest_id("i2c"); 1720 1721 down_write(&__i2c_board_lock); 1722 if (retval >= __i2c_first_dynamic_bus_num) 1723 __i2c_first_dynamic_bus_num = retval + 1; 1724 up_write(&__i2c_board_lock); 1725 1726 retval = bus_register(&i2c_bus_type); 1727 if (retval) 1728 return retval; 1729 1730 is_registered = true; 1731 1732 #ifdef CONFIG_I2C_COMPAT 1733 i2c_adapter_compat_class = class_compat_register("i2c-adapter"); 1734 if (!i2c_adapter_compat_class) { 1735 retval = -ENOMEM; 1736 goto bus_err; 1737 } 1738 #endif 1739 retval = i2c_add_driver(&dummy_driver); 1740 if (retval) 1741 goto class_err; 1742 1743 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 1744 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); 1745 if (IS_ENABLED(CONFIG_ACPI)) 1746 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier)); 1747 1748 return 0; 1749 1750 class_err: 1751 #ifdef CONFIG_I2C_COMPAT 1752 class_compat_unregister(i2c_adapter_compat_class); 1753 bus_err: 1754 #endif 1755 is_registered = false; 1756 bus_unregister(&i2c_bus_type); 1757 return retval; 1758 } 1759 1760 static void __exit i2c_exit(void) 1761 { 1762 if (IS_ENABLED(CONFIG_ACPI)) 1763 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier)); 1764 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 1765 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier)); 1766 i2c_del_driver(&dummy_driver); 1767 #ifdef CONFIG_I2C_COMPAT 1768 class_compat_unregister(i2c_adapter_compat_class); 1769 #endif 1770 bus_unregister(&i2c_bus_type); 1771 tracepoint_synchronize_unregister(); 1772 } 1773 1774 /* We must initialize early, because some subsystems register i2c drivers 1775 * in subsys_initcall() code, but are linked (and initialized) before i2c. 1776 */ 1777 postcore_initcall(i2c_init); 1778 module_exit(i2c_exit); 1779 1780 /* ---------------------------------------------------- 1781 * the functional interface to the i2c busses. 1782 * ---------------------------------------------------- 1783 */ 1784 1785 /* Check if val is exceeding the quirk IFF quirk is non 0 */ 1786 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) 1787 1788 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) 1789 { 1790 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n", 1791 err_msg, msg->addr, msg->len, 1792 msg->flags & I2C_M_RD ? "read" : "write"); 1793 return -EOPNOTSUPP; 1794 } 1795 1796 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 1797 { 1798 const struct i2c_adapter_quirks *q = adap->quirks; 1799 int max_num = q->max_num_msgs, i; 1800 bool do_len_check = true; 1801 1802 if (q->flags & I2C_AQ_COMB) { 1803 max_num = 2; 1804 1805 /* special checks for combined messages */ 1806 if (num == 2) { 1807 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD) 1808 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write"); 1809 1810 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD)) 1811 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read"); 1812 1813 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr) 1814 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr"); 1815 1816 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len)) 1817 return i2c_quirk_error(adap, &msgs[0], "msg too long"); 1818 1819 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len)) 1820 return i2c_quirk_error(adap, &msgs[1], "msg too long"); 1821 1822 do_len_check = false; 1823 } 1824 } 1825 1826 if (i2c_quirk_exceeded(num, max_num)) 1827 return i2c_quirk_error(adap, &msgs[0], "too many messages"); 1828 1829 for (i = 0; i < num; i++) { 1830 u16 len = msgs[i].len; 1831 1832 if (msgs[i].flags & I2C_M_RD) { 1833 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len)) 1834 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 1835 1836 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0) 1837 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 1838 } else { 1839 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len)) 1840 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 1841 1842 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0) 1843 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 1844 } 1845 } 1846 1847 return 0; 1848 } 1849 1850 /** 1851 * __i2c_transfer - unlocked flavor of i2c_transfer 1852 * @adap: Handle to I2C bus 1853 * @msgs: One or more messages to execute before STOP is issued to 1854 * terminate the operation; each message begins with a START. 1855 * @num: Number of messages to be executed. 1856 * 1857 * Returns negative errno, else the number of messages executed. 1858 * 1859 * Adapter lock must be held when calling this function. No debug logging 1860 * takes place. adap->algo->master_xfer existence isn't checked. 1861 */ 1862 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 1863 { 1864 unsigned long orig_jiffies; 1865 int ret, try; 1866 1867 if (WARN_ON(!msgs || num < 1)) 1868 return -EINVAL; 1869 1870 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) 1871 return -EOPNOTSUPP; 1872 1873 /* 1874 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets 1875 * enabled. This is an efficient way of keeping the for-loop from 1876 * being executed when not needed. 1877 */ 1878 if (static_branch_unlikely(&i2c_trace_msg_key)) { 1879 int i; 1880 for (i = 0; i < num; i++) 1881 if (msgs[i].flags & I2C_M_RD) 1882 trace_i2c_read(adap, &msgs[i], i); 1883 else 1884 trace_i2c_write(adap, &msgs[i], i); 1885 } 1886 1887 /* Retry automatically on arbitration loss */ 1888 orig_jiffies = jiffies; 1889 for (ret = 0, try = 0; try <= adap->retries; try++) { 1890 ret = adap->algo->master_xfer(adap, msgs, num); 1891 if (ret != -EAGAIN) 1892 break; 1893 if (time_after(jiffies, orig_jiffies + adap->timeout)) 1894 break; 1895 } 1896 1897 if (static_branch_unlikely(&i2c_trace_msg_key)) { 1898 int i; 1899 for (i = 0; i < ret; i++) 1900 if (msgs[i].flags & I2C_M_RD) 1901 trace_i2c_reply(adap, &msgs[i], i); 1902 trace_i2c_result(adap, num, ret); 1903 } 1904 1905 return ret; 1906 } 1907 EXPORT_SYMBOL(__i2c_transfer); 1908 1909 /** 1910 * i2c_transfer - execute a single or combined I2C message 1911 * @adap: Handle to I2C bus 1912 * @msgs: One or more messages to execute before STOP is issued to 1913 * terminate the operation; each message begins with a START. 1914 * @num: Number of messages to be executed. 1915 * 1916 * Returns negative errno, else the number of messages executed. 1917 * 1918 * Note that there is no requirement that each message be sent to 1919 * the same slave address, although that is the most common model. 1920 */ 1921 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 1922 { 1923 int ret; 1924 1925 /* REVISIT the fault reporting model here is weak: 1926 * 1927 * - When we get an error after receiving N bytes from a slave, 1928 * there is no way to report "N". 1929 * 1930 * - When we get a NAK after transmitting N bytes to a slave, 1931 * there is no way to report "N" ... or to let the master 1932 * continue executing the rest of this combined message, if 1933 * that's the appropriate response. 1934 * 1935 * - When for example "num" is two and we successfully complete 1936 * the first message but get an error part way through the 1937 * second, it's unclear whether that should be reported as 1938 * one (discarding status on the second message) or errno 1939 * (discarding status on the first one). 1940 */ 1941 1942 if (adap->algo->master_xfer) { 1943 #ifdef DEBUG 1944 for (ret = 0; ret < num; ret++) { 1945 dev_dbg(&adap->dev, 1946 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n", 1947 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W', 1948 msgs[ret].addr, msgs[ret].len, 1949 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : ""); 1950 } 1951 #endif 1952 1953 if (in_atomic() || irqs_disabled()) { 1954 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT); 1955 if (!ret) 1956 /* I2C activity is ongoing. */ 1957 return -EAGAIN; 1958 } else { 1959 i2c_lock_bus(adap, I2C_LOCK_SEGMENT); 1960 } 1961 1962 ret = __i2c_transfer(adap, msgs, num); 1963 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); 1964 1965 return ret; 1966 } else { 1967 dev_dbg(&adap->dev, "I2C level transfers not supported\n"); 1968 return -EOPNOTSUPP; 1969 } 1970 } 1971 EXPORT_SYMBOL(i2c_transfer); 1972 1973 /** 1974 * i2c_transfer_buffer_flags - issue a single I2C message transferring data 1975 * to/from a buffer 1976 * @client: Handle to slave device 1977 * @buf: Where the data is stored 1978 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16 1979 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads 1980 * 1981 * Returns negative errno, or else the number of bytes transferred. 1982 */ 1983 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf, 1984 int count, u16 flags) 1985 { 1986 int ret; 1987 struct i2c_msg msg = { 1988 .addr = client->addr, 1989 .flags = flags | (client->flags & I2C_M_TEN), 1990 .len = count, 1991 .buf = buf, 1992 }; 1993 1994 ret = i2c_transfer(client->adapter, &msg, 1); 1995 1996 /* 1997 * If everything went ok (i.e. 1 msg transferred), return #bytes 1998 * transferred, else error code. 1999 */ 2000 return (ret == 1) ? count : ret; 2001 } 2002 EXPORT_SYMBOL(i2c_transfer_buffer_flags); 2003 2004 /** 2005 * i2c_get_device_id - get manufacturer, part id and die revision of a device 2006 * @client: The device to query 2007 * @id: The queried information 2008 * 2009 * Returns negative errno on error, zero on success. 2010 */ 2011 int i2c_get_device_id(const struct i2c_client *client, 2012 struct i2c_device_identity *id) 2013 { 2014 struct i2c_adapter *adap = client->adapter; 2015 union i2c_smbus_data raw_id; 2016 int ret; 2017 2018 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) 2019 return -EOPNOTSUPP; 2020 2021 raw_id.block[0] = 3; 2022 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0, 2023 I2C_SMBUS_READ, client->addr << 1, 2024 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id); 2025 if (ret) 2026 return ret; 2027 2028 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4); 2029 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3); 2030 id->die_revision = raw_id.block[3] & 0x7; 2031 return 0; 2032 } 2033 EXPORT_SYMBOL_GPL(i2c_get_device_id); 2034 2035 /* ---------------------------------------------------- 2036 * the i2c address scanning function 2037 * Will not work for 10-bit addresses! 2038 * ---------------------------------------------------- 2039 */ 2040 2041 /* 2042 * Legacy default probe function, mostly relevant for SMBus. The default 2043 * probe method is a quick write, but it is known to corrupt the 24RF08 2044 * EEPROMs due to a state machine bug, and could also irreversibly 2045 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f, 2046 * we use a short byte read instead. Also, some bus drivers don't implement 2047 * quick write, so we fallback to a byte read in that case too. 2048 * On x86, there is another special case for FSC hardware monitoring chips, 2049 * which want regular byte reads (address 0x73.) Fortunately, these are the 2050 * only known chips using this I2C address on PC hardware. 2051 * Returns 1 if probe succeeded, 0 if not. 2052 */ 2053 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) 2054 { 2055 int err; 2056 union i2c_smbus_data dummy; 2057 2058 #ifdef CONFIG_X86 2059 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON) 2060 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA)) 2061 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2062 I2C_SMBUS_BYTE_DATA, &dummy); 2063 else 2064 #endif 2065 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) 2066 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) 2067 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, 2068 I2C_SMBUS_QUICK, NULL); 2069 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) 2070 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2071 I2C_SMBUS_BYTE, &dummy); 2072 else { 2073 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n", 2074 addr); 2075 err = -EOPNOTSUPP; 2076 } 2077 2078 return err >= 0; 2079 } 2080 2081 static int i2c_detect_address(struct i2c_client *temp_client, 2082 struct i2c_driver *driver) 2083 { 2084 struct i2c_board_info info; 2085 struct i2c_adapter *adapter = temp_client->adapter; 2086 int addr = temp_client->addr; 2087 int err; 2088 2089 /* Make sure the address is valid */ 2090 err = i2c_check_7bit_addr_validity_strict(addr); 2091 if (err) { 2092 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n", 2093 addr); 2094 return err; 2095 } 2096 2097 /* Skip if already in use (7 bit, no need to encode flags) */ 2098 if (i2c_check_addr_busy(adapter, addr)) 2099 return 0; 2100 2101 /* Make sure there is something at this address */ 2102 if (!i2c_default_probe(adapter, addr)) 2103 return 0; 2104 2105 /* Finally call the custom detection function */ 2106 memset(&info, 0, sizeof(struct i2c_board_info)); 2107 info.addr = addr; 2108 err = driver->detect(temp_client, &info); 2109 if (err) { 2110 /* -ENODEV is returned if the detection fails. We catch it 2111 here as this isn't an error. */ 2112 return err == -ENODEV ? 0 : err; 2113 } 2114 2115 /* Consistency check */ 2116 if (info.type[0] == '\0') { 2117 dev_err(&adapter->dev, 2118 "%s detection function provided no name for 0x%x\n", 2119 driver->driver.name, addr); 2120 } else { 2121 struct i2c_client *client; 2122 2123 /* Detection succeeded, instantiate the device */ 2124 if (adapter->class & I2C_CLASS_DEPRECATED) 2125 dev_warn(&adapter->dev, 2126 "This adapter will soon drop class based instantiation of devices. " 2127 "Please make sure client 0x%02x gets instantiated by other means. " 2128 "Check 'Documentation/i2c/instantiating-devices' for details.\n", 2129 info.addr); 2130 2131 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n", 2132 info.type, info.addr); 2133 client = i2c_new_device(adapter, &info); 2134 if (client) 2135 list_add_tail(&client->detected, &driver->clients); 2136 else 2137 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n", 2138 info.type, info.addr); 2139 } 2140 return 0; 2141 } 2142 2143 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) 2144 { 2145 const unsigned short *address_list; 2146 struct i2c_client *temp_client; 2147 int i, err = 0; 2148 int adap_id = i2c_adapter_id(adapter); 2149 2150 address_list = driver->address_list; 2151 if (!driver->detect || !address_list) 2152 return 0; 2153 2154 /* Warn that the adapter lost class based instantiation */ 2155 if (adapter->class == I2C_CLASS_DEPRECATED) { 2156 dev_dbg(&adapter->dev, 2157 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. " 2158 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n", 2159 driver->driver.name); 2160 return 0; 2161 } 2162 2163 /* Stop here if the classes do not match */ 2164 if (!(adapter->class & driver->class)) 2165 return 0; 2166 2167 /* Set up a temporary client to help detect callback */ 2168 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); 2169 if (!temp_client) 2170 return -ENOMEM; 2171 temp_client->adapter = adapter; 2172 2173 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { 2174 dev_dbg(&adapter->dev, 2175 "found normal entry for adapter %d, addr 0x%02x\n", 2176 adap_id, address_list[i]); 2177 temp_client->addr = address_list[i]; 2178 err = i2c_detect_address(temp_client, driver); 2179 if (unlikely(err)) 2180 break; 2181 } 2182 2183 kfree(temp_client); 2184 return err; 2185 } 2186 2187 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) 2188 { 2189 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2190 I2C_SMBUS_QUICK, NULL) >= 0; 2191 } 2192 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); 2193 2194 struct i2c_client * 2195 i2c_new_probed_device(struct i2c_adapter *adap, 2196 struct i2c_board_info *info, 2197 unsigned short const *addr_list, 2198 int (*probe)(struct i2c_adapter *, unsigned short addr)) 2199 { 2200 int i; 2201 2202 if (!probe) 2203 probe = i2c_default_probe; 2204 2205 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { 2206 /* Check address validity */ 2207 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) { 2208 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n", 2209 addr_list[i]); 2210 continue; 2211 } 2212 2213 /* Check address availability (7 bit, no need to encode flags) */ 2214 if (i2c_check_addr_busy(adap, addr_list[i])) { 2215 dev_dbg(&adap->dev, 2216 "Address 0x%02x already in use, not probing\n", 2217 addr_list[i]); 2218 continue; 2219 } 2220 2221 /* Test address responsiveness */ 2222 if (probe(adap, addr_list[i])) 2223 break; 2224 } 2225 2226 if (addr_list[i] == I2C_CLIENT_END) { 2227 dev_dbg(&adap->dev, "Probing failed, no device found\n"); 2228 return NULL; 2229 } 2230 2231 info->addr = addr_list[i]; 2232 return i2c_new_device(adap, info); 2233 } 2234 EXPORT_SYMBOL_GPL(i2c_new_probed_device); 2235 2236 struct i2c_adapter *i2c_get_adapter(int nr) 2237 { 2238 struct i2c_adapter *adapter; 2239 2240 mutex_lock(&core_lock); 2241 adapter = idr_find(&i2c_adapter_idr, nr); 2242 if (!adapter) 2243 goto exit; 2244 2245 if (try_module_get(adapter->owner)) 2246 get_device(&adapter->dev); 2247 else 2248 adapter = NULL; 2249 2250 exit: 2251 mutex_unlock(&core_lock); 2252 return adapter; 2253 } 2254 EXPORT_SYMBOL(i2c_get_adapter); 2255 2256 void i2c_put_adapter(struct i2c_adapter *adap) 2257 { 2258 if (!adap) 2259 return; 2260 2261 put_device(&adap->dev); 2262 module_put(adap->owner); 2263 } 2264 EXPORT_SYMBOL(i2c_put_adapter); 2265 2266 /** 2267 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg 2268 * @msg: the message to be checked 2269 * @threshold: the minimum number of bytes for which using DMA makes sense 2270 * 2271 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO. 2272 * Or a valid pointer to be used with DMA. After use, release it by 2273 * calling i2c_release_dma_safe_msg_buf(). 2274 * 2275 * This function must only be called from process context! 2276 */ 2277 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold) 2278 { 2279 if (msg->len < threshold) 2280 return NULL; 2281 2282 if (msg->flags & I2C_M_DMA_SAFE) 2283 return msg->buf; 2284 2285 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n", 2286 msg->addr, msg->len); 2287 2288 if (msg->flags & I2C_M_RD) 2289 return kzalloc(msg->len, GFP_KERNEL); 2290 else 2291 return kmemdup(msg->buf, msg->len, GFP_KERNEL); 2292 } 2293 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf); 2294 2295 /** 2296 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg 2297 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL. 2298 * @msg: the message which the buffer corresponds to 2299 * @xferred: bool saying if the message was transferred 2300 */ 2301 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred) 2302 { 2303 if (!buf || buf == msg->buf) 2304 return; 2305 2306 if (xferred && msg->flags & I2C_M_RD) 2307 memcpy(msg->buf, buf, msg->len); 2308 2309 kfree(buf); 2310 } 2311 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf); 2312 2313 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 2314 MODULE_DESCRIPTION("I2C-Bus main module"); 2315 MODULE_LICENSE("GPL"); 2316