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