1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux I2C core 4 * 5 * Copyright (C) 1995-99 Simon G. Vogl 6 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> 7 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and 8 * Michael Lawnick <michael.lawnick.ext@nsn.com> 9 * 10 * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org> 11 */ 12 13 #define pr_fmt(fmt) "i2c-core: " fmt 14 15 #include <dt-bindings/i2c/i2c.h> 16 #include <linux/acpi.h> 17 #include <linux/clk/clk-conf.h> 18 #include <linux/completion.h> 19 #include <linux/delay.h> 20 #include <linux/err.h> 21 #include <linux/errno.h> 22 #include <linux/gpio/consumer.h> 23 #include <linux/i2c.h> 24 #include <linux/i2c-smbus.h> 25 #include <linux/idr.h> 26 #include <linux/init.h> 27 #include <linux/irqflags.h> 28 #include <linux/jump_label.h> 29 #include <linux/kernel.h> 30 #include <linux/module.h> 31 #include <linux/mutex.h> 32 #include <linux/of_device.h> 33 #include <linux/of.h> 34 #include <linux/of_irq.h> 35 #include <linux/pinctrl/consumer.h> 36 #include <linux/pm_domain.h> 37 #include <linux/pm_runtime.h> 38 #include <linux/pm_wakeirq.h> 39 #include <linux/property.h> 40 #include <linux/rwsem.h> 41 #include <linux/slab.h> 42 43 #include "i2c-core.h" 44 45 #define CREATE_TRACE_POINTS 46 #include <trace/events/i2c.h> 47 48 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000 49 #define I2C_ADDR_OFFSET_SLAVE 0x1000 50 51 #define I2C_ADDR_7BITS_MAX 0x77 52 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1) 53 54 #define I2C_ADDR_DEVICE_ID 0x7c 55 56 /* 57 * core_lock protects i2c_adapter_idr, and guarantees that device detection, 58 * deletion of detected devices are serialized 59 */ 60 static DEFINE_MUTEX(core_lock); 61 static DEFINE_IDR(i2c_adapter_idr); 62 63 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); 64 65 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key); 66 static bool is_registered; 67 68 int i2c_transfer_trace_reg(void) 69 { 70 static_branch_inc(&i2c_trace_msg_key); 71 return 0; 72 } 73 74 void i2c_transfer_trace_unreg(void) 75 { 76 static_branch_dec(&i2c_trace_msg_key); 77 } 78 79 const char *i2c_freq_mode_string(u32 bus_freq_hz) 80 { 81 switch (bus_freq_hz) { 82 case I2C_MAX_STANDARD_MODE_FREQ: 83 return "Standard Mode (100 kHz)"; 84 case I2C_MAX_FAST_MODE_FREQ: 85 return "Fast Mode (400 kHz)"; 86 case I2C_MAX_FAST_MODE_PLUS_FREQ: 87 return "Fast Mode Plus (1.0 MHz)"; 88 case I2C_MAX_TURBO_MODE_FREQ: 89 return "Turbo Mode (1.4 MHz)"; 90 case I2C_MAX_HIGH_SPEED_MODE_FREQ: 91 return "High Speed Mode (3.4 MHz)"; 92 case I2C_MAX_ULTRA_FAST_MODE_FREQ: 93 return "Ultra Fast Mode (5.0 MHz)"; 94 default: 95 return "Unknown Mode"; 96 } 97 } 98 EXPORT_SYMBOL_GPL(i2c_freq_mode_string); 99 100 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, 101 const struct i2c_client *client) 102 { 103 if (!(id && client)) 104 return NULL; 105 106 while (id->name[0]) { 107 if (strcmp(client->name, id->name) == 0) 108 return id; 109 id++; 110 } 111 return NULL; 112 } 113 EXPORT_SYMBOL_GPL(i2c_match_id); 114 115 static int i2c_device_match(struct device *dev, struct device_driver *drv) 116 { 117 struct i2c_client *client = i2c_verify_client(dev); 118 struct i2c_driver *driver; 119 120 121 /* Attempt an OF style match */ 122 if (i2c_of_match_device(drv->of_match_table, client)) 123 return 1; 124 125 /* Then ACPI style match */ 126 if (acpi_driver_match_device(dev, drv)) 127 return 1; 128 129 driver = to_i2c_driver(drv); 130 131 /* Finally an I2C match */ 132 if (i2c_match_id(driver->id_table, client)) 133 return 1; 134 135 return 0; 136 } 137 138 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env) 139 { 140 struct i2c_client *client = to_i2c_client(dev); 141 int rc; 142 143 rc = of_device_uevent_modalias(dev, env); 144 if (rc != -ENODEV) 145 return rc; 146 147 rc = acpi_device_uevent_modalias(dev, env); 148 if (rc != -ENODEV) 149 return rc; 150 151 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name); 152 } 153 154 /* i2c bus recovery routines */ 155 static int get_scl_gpio_value(struct i2c_adapter *adap) 156 { 157 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod); 158 } 159 160 static void set_scl_gpio_value(struct i2c_adapter *adap, int val) 161 { 162 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val); 163 } 164 165 static int get_sda_gpio_value(struct i2c_adapter *adap) 166 { 167 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod); 168 } 169 170 static void set_sda_gpio_value(struct i2c_adapter *adap, int val) 171 { 172 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val); 173 } 174 175 static int i2c_generic_bus_free(struct i2c_adapter *adap) 176 { 177 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 178 int ret = -EOPNOTSUPP; 179 180 if (bri->get_bus_free) 181 ret = bri->get_bus_free(adap); 182 else if (bri->get_sda) 183 ret = bri->get_sda(adap); 184 185 if (ret < 0) 186 return ret; 187 188 return ret ? 0 : -EBUSY; 189 } 190 191 /* 192 * We are generating clock pulses. ndelay() determines durating of clk pulses. 193 * We will generate clock with rate 100 KHz and so duration of both clock levels 194 * is: delay in ns = (10^6 / 100) / 2 195 */ 196 #define RECOVERY_NDELAY 5000 197 #define RECOVERY_CLK_CNT 9 198 199 int i2c_generic_scl_recovery(struct i2c_adapter *adap) 200 { 201 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 202 int i = 0, scl = 1, ret = 0; 203 204 if (bri->prepare_recovery) 205 bri->prepare_recovery(adap); 206 if (bri->pinctrl) 207 pinctrl_select_state(bri->pinctrl, bri->pins_gpio); 208 209 /* 210 * If we can set SDA, we will always create a STOP to ensure additional 211 * pulses will do no harm. This is achieved by letting SDA follow SCL 212 * half a cycle later. Check the 'incomplete_write_byte' fault injector 213 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us 214 * here for simplicity. 215 */ 216 bri->set_scl(adap, scl); 217 ndelay(RECOVERY_NDELAY); 218 if (bri->set_sda) 219 bri->set_sda(adap, scl); 220 ndelay(RECOVERY_NDELAY / 2); 221 222 /* 223 * By this time SCL is high, as we need to give 9 falling-rising edges 224 */ 225 while (i++ < RECOVERY_CLK_CNT * 2) { 226 if (scl) { 227 /* SCL shouldn't be low here */ 228 if (!bri->get_scl(adap)) { 229 dev_err(&adap->dev, 230 "SCL is stuck low, exit recovery\n"); 231 ret = -EBUSY; 232 break; 233 } 234 } 235 236 scl = !scl; 237 bri->set_scl(adap, scl); 238 /* Creating STOP again, see above */ 239 if (scl) { 240 /* Honour minimum tsu:sto */ 241 ndelay(RECOVERY_NDELAY); 242 } else { 243 /* Honour minimum tf and thd:dat */ 244 ndelay(RECOVERY_NDELAY / 2); 245 } 246 if (bri->set_sda) 247 bri->set_sda(adap, scl); 248 ndelay(RECOVERY_NDELAY / 2); 249 250 if (scl) { 251 ret = i2c_generic_bus_free(adap); 252 if (ret == 0) 253 break; 254 } 255 } 256 257 /* If we can't check bus status, assume recovery worked */ 258 if (ret == -EOPNOTSUPP) 259 ret = 0; 260 261 if (bri->unprepare_recovery) 262 bri->unprepare_recovery(adap); 263 if (bri->pinctrl) 264 pinctrl_select_state(bri->pinctrl, bri->pins_default); 265 266 return ret; 267 } 268 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery); 269 270 int i2c_recover_bus(struct i2c_adapter *adap) 271 { 272 if (!adap->bus_recovery_info) 273 return -EBUSY; 274 275 dev_dbg(&adap->dev, "Trying i2c bus recovery\n"); 276 return adap->bus_recovery_info->recover_bus(adap); 277 } 278 EXPORT_SYMBOL_GPL(i2c_recover_bus); 279 280 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap) 281 { 282 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 283 struct device *dev = &adap->dev; 284 struct pinctrl *p = bri->pinctrl; 285 286 /* 287 * we can't change states without pinctrl, so remove the states if 288 * populated 289 */ 290 if (!p) { 291 bri->pins_default = NULL; 292 bri->pins_gpio = NULL; 293 return; 294 } 295 296 if (!bri->pins_default) { 297 bri->pins_default = pinctrl_lookup_state(p, 298 PINCTRL_STATE_DEFAULT); 299 if (IS_ERR(bri->pins_default)) { 300 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n"); 301 bri->pins_default = NULL; 302 } 303 } 304 if (!bri->pins_gpio) { 305 bri->pins_gpio = pinctrl_lookup_state(p, "gpio"); 306 if (IS_ERR(bri->pins_gpio)) 307 bri->pins_gpio = pinctrl_lookup_state(p, "recovery"); 308 309 if (IS_ERR(bri->pins_gpio)) { 310 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n"); 311 bri->pins_gpio = NULL; 312 } 313 } 314 315 /* for pinctrl state changes, we need all the information */ 316 if (bri->pins_default && bri->pins_gpio) { 317 dev_info(dev, "using pinctrl states for GPIO recovery"); 318 } else { 319 bri->pinctrl = NULL; 320 bri->pins_default = NULL; 321 bri->pins_gpio = NULL; 322 } 323 } 324 325 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap) 326 { 327 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 328 struct device *dev = &adap->dev; 329 struct gpio_desc *gpiod; 330 int ret = 0; 331 332 /* 333 * don't touch the recovery information if the driver is not using 334 * generic SCL recovery 335 */ 336 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery) 337 return 0; 338 339 /* 340 * pins might be taken as GPIO, so we should inform pinctrl about 341 * this and move the state to GPIO 342 */ 343 if (bri->pinctrl) 344 pinctrl_select_state(bri->pinctrl, bri->pins_gpio); 345 346 /* 347 * if there is incomplete or no recovery information, see if generic 348 * GPIO recovery is available 349 */ 350 if (!bri->scl_gpiod) { 351 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); 352 if (PTR_ERR(gpiod) == -EPROBE_DEFER) { 353 ret = -EPROBE_DEFER; 354 goto cleanup_pinctrl_state; 355 } 356 if (!IS_ERR(gpiod)) { 357 bri->scl_gpiod = gpiod; 358 bri->recover_bus = i2c_generic_scl_recovery; 359 dev_info(dev, "using generic GPIOs for recovery\n"); 360 } 361 } 362 363 /* SDA GPIOD line is optional, so we care about DEFER only */ 364 if (!bri->sda_gpiod) { 365 /* 366 * We have SCL. Pull SCL low and wait a bit so that SDA glitches 367 * have no effect. 368 */ 369 gpiod_direction_output(bri->scl_gpiod, 0); 370 udelay(10); 371 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN); 372 373 /* Wait a bit in case of a SDA glitch, and then release SCL. */ 374 udelay(10); 375 gpiod_direction_output(bri->scl_gpiod, 1); 376 377 if (PTR_ERR(gpiod) == -EPROBE_DEFER) { 378 ret = -EPROBE_DEFER; 379 goto cleanup_pinctrl_state; 380 } 381 if (!IS_ERR(gpiod)) 382 bri->sda_gpiod = gpiod; 383 } 384 385 cleanup_pinctrl_state: 386 /* change the state of the pins back to their default state */ 387 if (bri->pinctrl) 388 pinctrl_select_state(bri->pinctrl, bri->pins_default); 389 390 return ret; 391 } 392 393 static int i2c_gpio_init_recovery(struct i2c_adapter *adap) 394 { 395 i2c_gpio_init_pinctrl_recovery(adap); 396 return i2c_gpio_init_generic_recovery(adap); 397 } 398 399 static int i2c_init_recovery(struct i2c_adapter *adap) 400 { 401 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 402 char *err_str, *err_level = KERN_ERR; 403 404 if (!bri) 405 return 0; 406 407 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER) 408 return -EPROBE_DEFER; 409 410 if (!bri->recover_bus) { 411 err_str = "no suitable method provided"; 412 err_level = KERN_DEBUG; 413 goto err; 414 } 415 416 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) { 417 bri->get_scl = get_scl_gpio_value; 418 bri->set_scl = set_scl_gpio_value; 419 if (bri->sda_gpiod) { 420 bri->get_sda = get_sda_gpio_value; 421 /* FIXME: add proper flag instead of '0' once available */ 422 if (gpiod_get_direction(bri->sda_gpiod) == 0) 423 bri->set_sda = set_sda_gpio_value; 424 } 425 } else if (bri->recover_bus == i2c_generic_scl_recovery) { 426 /* Generic SCL recovery */ 427 if (!bri->set_scl || !bri->get_scl) { 428 err_str = "no {get|set}_scl() found"; 429 goto err; 430 } 431 if (!bri->set_sda && !bri->get_sda) { 432 err_str = "either get_sda() or set_sda() needed"; 433 goto err; 434 } 435 } 436 437 return 0; 438 err: 439 dev_printk(err_level, &adap->dev, "Not using recovery: %s\n", err_str); 440 adap->bus_recovery_info = NULL; 441 442 return -EINVAL; 443 } 444 445 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client) 446 { 447 struct i2c_adapter *adap = client->adapter; 448 unsigned int irq; 449 450 if (!adap->host_notify_domain) 451 return -ENXIO; 452 453 if (client->flags & I2C_CLIENT_TEN) 454 return -EINVAL; 455 456 irq = irq_create_mapping(adap->host_notify_domain, client->addr); 457 458 return irq > 0 ? irq : -ENXIO; 459 } 460 461 static int i2c_device_probe(struct device *dev) 462 { 463 struct i2c_client *client = i2c_verify_client(dev); 464 struct i2c_driver *driver; 465 int status; 466 467 if (!client) 468 return 0; 469 470 client->irq = client->init_irq; 471 472 if (!client->irq) { 473 int irq = -ENOENT; 474 475 if (client->flags & I2C_CLIENT_HOST_NOTIFY) { 476 dev_dbg(dev, "Using Host Notify IRQ\n"); 477 /* Keep adapter active when Host Notify is required */ 478 pm_runtime_get_sync(&client->adapter->dev); 479 irq = i2c_smbus_host_notify_to_irq(client); 480 } else if (dev->of_node) { 481 irq = of_irq_get_byname(dev->of_node, "irq"); 482 if (irq == -EINVAL || irq == -ENODATA) 483 irq = of_irq_get(dev->of_node, 0); 484 } else if (ACPI_COMPANION(dev)) { 485 irq = i2c_acpi_get_irq(client); 486 } 487 if (irq == -EPROBE_DEFER) { 488 status = irq; 489 goto put_sync_adapter; 490 } 491 492 if (irq < 0) 493 irq = 0; 494 495 client->irq = irq; 496 } 497 498 driver = to_i2c_driver(dev->driver); 499 500 /* 501 * An I2C ID table is not mandatory, if and only if, a suitable OF 502 * or ACPI ID table is supplied for the probing device. 503 */ 504 if (!driver->id_table && 505 !acpi_driver_match_device(dev, dev->driver) && 506 !i2c_of_match_device(dev->driver->of_match_table, client)) { 507 status = -ENODEV; 508 goto put_sync_adapter; 509 } 510 511 if (client->flags & I2C_CLIENT_WAKE) { 512 int wakeirq; 513 514 wakeirq = of_irq_get_byname(dev->of_node, "wakeup"); 515 if (wakeirq == -EPROBE_DEFER) { 516 status = wakeirq; 517 goto put_sync_adapter; 518 } 519 520 device_init_wakeup(&client->dev, true); 521 522 if (wakeirq > 0 && wakeirq != client->irq) 523 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq); 524 else if (client->irq > 0) 525 status = dev_pm_set_wake_irq(dev, client->irq); 526 else 527 status = 0; 528 529 if (status) 530 dev_warn(&client->dev, "failed to set up wakeup irq\n"); 531 } 532 533 dev_dbg(dev, "probe\n"); 534 535 status = of_clk_set_defaults(dev->of_node, false); 536 if (status < 0) 537 goto err_clear_wakeup_irq; 538 539 status = dev_pm_domain_attach(&client->dev, true); 540 if (status) 541 goto err_clear_wakeup_irq; 542 543 client->devres_group_id = devres_open_group(&client->dev, NULL, 544 GFP_KERNEL); 545 if (!client->devres_group_id) { 546 status = -ENOMEM; 547 goto err_detach_pm_domain; 548 } 549 550 /* 551 * When there are no more users of probe(), 552 * rename probe_new to probe. 553 */ 554 if (driver->probe_new) 555 status = driver->probe_new(client); 556 else if (driver->probe) 557 status = driver->probe(client, 558 i2c_match_id(driver->id_table, client)); 559 else 560 status = -EINVAL; 561 562 /* 563 * Note that we are not closing the devres group opened above so 564 * even resources that were attached to the device after probe is 565 * run are released when i2c_device_remove() is executed. This is 566 * needed as some drivers would allocate additional resources, 567 * for example when updating firmware. 568 */ 569 570 if (status) 571 goto err_release_driver_resources; 572 573 return 0; 574 575 err_release_driver_resources: 576 devres_release_group(&client->dev, client->devres_group_id); 577 err_detach_pm_domain: 578 dev_pm_domain_detach(&client->dev, true); 579 err_clear_wakeup_irq: 580 dev_pm_clear_wake_irq(&client->dev); 581 device_init_wakeup(&client->dev, false); 582 put_sync_adapter: 583 if (client->flags & I2C_CLIENT_HOST_NOTIFY) 584 pm_runtime_put_sync(&client->adapter->dev); 585 586 return status; 587 } 588 589 static int i2c_device_remove(struct device *dev) 590 { 591 struct i2c_client *client = to_i2c_client(dev); 592 struct i2c_driver *driver; 593 594 driver = to_i2c_driver(dev->driver); 595 if (driver->remove) { 596 int status; 597 598 dev_dbg(dev, "remove\n"); 599 600 status = driver->remove(client); 601 if (status) 602 dev_warn(dev, "remove failed (%pe), will be ignored\n", ERR_PTR(status)); 603 } 604 605 devres_release_group(&client->dev, client->devres_group_id); 606 607 dev_pm_domain_detach(&client->dev, true); 608 609 dev_pm_clear_wake_irq(&client->dev); 610 device_init_wakeup(&client->dev, false); 611 612 client->irq = 0; 613 if (client->flags & I2C_CLIENT_HOST_NOTIFY) 614 pm_runtime_put(&client->adapter->dev); 615 616 /* return always 0 because there is WIP to make remove-functions void */ 617 return 0; 618 } 619 620 static void i2c_device_shutdown(struct device *dev) 621 { 622 struct i2c_client *client = i2c_verify_client(dev); 623 struct i2c_driver *driver; 624 625 if (!client || !dev->driver) 626 return; 627 driver = to_i2c_driver(dev->driver); 628 if (driver->shutdown) 629 driver->shutdown(client); 630 } 631 632 static void i2c_client_dev_release(struct device *dev) 633 { 634 kfree(to_i2c_client(dev)); 635 } 636 637 static ssize_t 638 name_show(struct device *dev, struct device_attribute *attr, char *buf) 639 { 640 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? 641 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); 642 } 643 static DEVICE_ATTR_RO(name); 644 645 static ssize_t 646 modalias_show(struct device *dev, struct device_attribute *attr, char *buf) 647 { 648 struct i2c_client *client = to_i2c_client(dev); 649 int len; 650 651 len = of_device_modalias(dev, buf, PAGE_SIZE); 652 if (len != -ENODEV) 653 return len; 654 655 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); 656 if (len != -ENODEV) 657 return len; 658 659 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); 660 } 661 static DEVICE_ATTR_RO(modalias); 662 663 static struct attribute *i2c_dev_attrs[] = { 664 &dev_attr_name.attr, 665 /* modalias helps coldplug: modprobe $(cat .../modalias) */ 666 &dev_attr_modalias.attr, 667 NULL 668 }; 669 ATTRIBUTE_GROUPS(i2c_dev); 670 671 struct bus_type i2c_bus_type = { 672 .name = "i2c", 673 .match = i2c_device_match, 674 .probe = i2c_device_probe, 675 .remove = i2c_device_remove, 676 .shutdown = i2c_device_shutdown, 677 }; 678 EXPORT_SYMBOL_GPL(i2c_bus_type); 679 680 struct device_type i2c_client_type = { 681 .groups = i2c_dev_groups, 682 .uevent = i2c_device_uevent, 683 .release = i2c_client_dev_release, 684 }; 685 EXPORT_SYMBOL_GPL(i2c_client_type); 686 687 688 /** 689 * i2c_verify_client - return parameter as i2c_client, or NULL 690 * @dev: device, probably from some driver model iterator 691 * 692 * When traversing the driver model tree, perhaps using driver model 693 * iterators like @device_for_each_child(), you can't assume very much 694 * about the nodes you find. Use this function to avoid oopses caused 695 * by wrongly treating some non-I2C device as an i2c_client. 696 */ 697 struct i2c_client *i2c_verify_client(struct device *dev) 698 { 699 return (dev->type == &i2c_client_type) 700 ? to_i2c_client(dev) 701 : NULL; 702 } 703 EXPORT_SYMBOL(i2c_verify_client); 704 705 706 /* Return a unique address which takes the flags of the client into account */ 707 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client) 708 { 709 unsigned short addr = client->addr; 710 711 /* For some client flags, add an arbitrary offset to avoid collisions */ 712 if (client->flags & I2C_CLIENT_TEN) 713 addr |= I2C_ADDR_OFFSET_TEN_BIT; 714 715 if (client->flags & I2C_CLIENT_SLAVE) 716 addr |= I2C_ADDR_OFFSET_SLAVE; 717 718 return addr; 719 } 720 721 /* This is a permissive address validity check, I2C address map constraints 722 * are purposely not enforced, except for the general call address. */ 723 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags) 724 { 725 if (flags & I2C_CLIENT_TEN) { 726 /* 10-bit address, all values are valid */ 727 if (addr > 0x3ff) 728 return -EINVAL; 729 } else { 730 /* 7-bit address, reject the general call address */ 731 if (addr == 0x00 || addr > 0x7f) 732 return -EINVAL; 733 } 734 return 0; 735 } 736 737 /* And this is a strict address validity check, used when probing. If a 738 * device uses a reserved address, then it shouldn't be probed. 7-bit 739 * addressing is assumed, 10-bit address devices are rare and should be 740 * explicitly enumerated. */ 741 int i2c_check_7bit_addr_validity_strict(unsigned short addr) 742 { 743 /* 744 * Reserved addresses per I2C specification: 745 * 0x00 General call address / START byte 746 * 0x01 CBUS address 747 * 0x02 Reserved for different bus format 748 * 0x03 Reserved for future purposes 749 * 0x04-0x07 Hs-mode master code 750 * 0x78-0x7b 10-bit slave addressing 751 * 0x7c-0x7f Reserved for future purposes 752 */ 753 if (addr < 0x08 || addr > 0x77) 754 return -EINVAL; 755 return 0; 756 } 757 758 static int __i2c_check_addr_busy(struct device *dev, void *addrp) 759 { 760 struct i2c_client *client = i2c_verify_client(dev); 761 int addr = *(int *)addrp; 762 763 if (client && i2c_encode_flags_to_addr(client) == addr) 764 return -EBUSY; 765 return 0; 766 } 767 768 /* walk up mux tree */ 769 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) 770 { 771 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 772 int result; 773 774 result = device_for_each_child(&adapter->dev, &addr, 775 __i2c_check_addr_busy); 776 777 if (!result && parent) 778 result = i2c_check_mux_parents(parent, addr); 779 780 return result; 781 } 782 783 /* recurse down mux tree */ 784 static int i2c_check_mux_children(struct device *dev, void *addrp) 785 { 786 int result; 787 788 if (dev->type == &i2c_adapter_type) 789 result = device_for_each_child(dev, addrp, 790 i2c_check_mux_children); 791 else 792 result = __i2c_check_addr_busy(dev, addrp); 793 794 return result; 795 } 796 797 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) 798 { 799 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 800 int result = 0; 801 802 if (parent) 803 result = i2c_check_mux_parents(parent, addr); 804 805 if (!result) 806 result = device_for_each_child(&adapter->dev, &addr, 807 i2c_check_mux_children); 808 809 return result; 810 } 811 812 /** 813 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment 814 * @adapter: Target I2C bus segment 815 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT 816 * locks only this branch in the adapter tree 817 */ 818 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, 819 unsigned int flags) 820 { 821 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); 822 } 823 824 /** 825 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment 826 * @adapter: Target I2C bus segment 827 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT 828 * trylocks only this branch in the adapter tree 829 */ 830 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, 831 unsigned int flags) 832 { 833 return rt_mutex_trylock(&adapter->bus_lock); 834 } 835 836 /** 837 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment 838 * @adapter: Target I2C bus segment 839 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT 840 * unlocks only this branch in the adapter tree 841 */ 842 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, 843 unsigned int flags) 844 { 845 rt_mutex_unlock(&adapter->bus_lock); 846 } 847 848 static void i2c_dev_set_name(struct i2c_adapter *adap, 849 struct i2c_client *client, 850 struct i2c_board_info const *info) 851 { 852 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 853 854 if (info && info->dev_name) { 855 dev_set_name(&client->dev, "i2c-%s", info->dev_name); 856 return; 857 } 858 859 if (adev) { 860 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev)); 861 return; 862 } 863 864 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), 865 i2c_encode_flags_to_addr(client)); 866 } 867 868 int i2c_dev_irq_from_resources(const struct resource *resources, 869 unsigned int num_resources) 870 { 871 struct irq_data *irqd; 872 int i; 873 874 for (i = 0; i < num_resources; i++) { 875 const struct resource *r = &resources[i]; 876 877 if (resource_type(r) != IORESOURCE_IRQ) 878 continue; 879 880 if (r->flags & IORESOURCE_BITS) { 881 irqd = irq_get_irq_data(r->start); 882 if (!irqd) 883 break; 884 885 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); 886 } 887 888 return r->start; 889 } 890 891 return 0; 892 } 893 894 /** 895 * i2c_new_client_device - instantiate an i2c device 896 * @adap: the adapter managing the device 897 * @info: describes one I2C device; bus_num is ignored 898 * Context: can sleep 899 * 900 * Create an i2c device. Binding is handled through driver model 901 * probe()/remove() methods. A driver may be bound to this device when we 902 * return from this function, or any later moment (e.g. maybe hotplugging will 903 * load the driver module). This call is not appropriate for use by mainboard 904 * initialization logic, which usually runs during an arch_initcall() long 905 * before any i2c_adapter could exist. 906 * 907 * This returns the new i2c client, which may be saved for later use with 908 * i2c_unregister_device(); or an ERR_PTR to describe the error. 909 */ 910 struct i2c_client * 911 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info) 912 { 913 struct i2c_client *client; 914 int status; 915 916 client = kzalloc(sizeof *client, GFP_KERNEL); 917 if (!client) 918 return ERR_PTR(-ENOMEM); 919 920 client->adapter = adap; 921 922 client->dev.platform_data = info->platform_data; 923 client->flags = info->flags; 924 client->addr = info->addr; 925 926 client->init_irq = info->irq; 927 if (!client->init_irq) 928 client->init_irq = i2c_dev_irq_from_resources(info->resources, 929 info->num_resources); 930 931 strlcpy(client->name, info->type, sizeof(client->name)); 932 933 status = i2c_check_addr_validity(client->addr, client->flags); 934 if (status) { 935 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", 936 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); 937 goto out_err_silent; 938 } 939 940 /* Check for address business */ 941 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); 942 if (status) 943 goto out_err; 944 945 client->dev.parent = &client->adapter->dev; 946 client->dev.bus = &i2c_bus_type; 947 client->dev.type = &i2c_client_type; 948 client->dev.of_node = of_node_get(info->of_node); 949 client->dev.fwnode = info->fwnode; 950 951 i2c_dev_set_name(adap, client, info); 952 953 if (info->swnode) { 954 status = device_add_software_node(&client->dev, info->swnode); 955 if (status) { 956 dev_err(&adap->dev, 957 "Failed to add software node to client %s: %d\n", 958 client->name, status); 959 goto out_err_put_of_node; 960 } 961 } 962 963 status = device_register(&client->dev); 964 if (status) 965 goto out_remove_swnode; 966 967 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", 968 client->name, dev_name(&client->dev)); 969 970 return client; 971 972 out_remove_swnode: 973 device_remove_software_node(&client->dev); 974 out_err_put_of_node: 975 of_node_put(info->of_node); 976 out_err: 977 dev_err(&adap->dev, 978 "Failed to register i2c client %s at 0x%02x (%d)\n", 979 client->name, client->addr, status); 980 out_err_silent: 981 kfree(client); 982 return ERR_PTR(status); 983 } 984 EXPORT_SYMBOL_GPL(i2c_new_client_device); 985 986 /** 987 * i2c_unregister_device - reverse effect of i2c_new_*_device() 988 * @client: value returned from i2c_new_*_device() 989 * Context: can sleep 990 */ 991 void i2c_unregister_device(struct i2c_client *client) 992 { 993 if (IS_ERR_OR_NULL(client)) 994 return; 995 996 if (client->dev.of_node) { 997 of_node_clear_flag(client->dev.of_node, OF_POPULATED); 998 of_node_put(client->dev.of_node); 999 } 1000 1001 if (ACPI_COMPANION(&client->dev)) 1002 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev)); 1003 device_remove_software_node(&client->dev); 1004 device_unregister(&client->dev); 1005 } 1006 EXPORT_SYMBOL_GPL(i2c_unregister_device); 1007 1008 1009 static const struct i2c_device_id dummy_id[] = { 1010 { "dummy", 0 }, 1011 { }, 1012 }; 1013 1014 static int dummy_probe(struct i2c_client *client, 1015 const struct i2c_device_id *id) 1016 { 1017 return 0; 1018 } 1019 1020 static int dummy_remove(struct i2c_client *client) 1021 { 1022 return 0; 1023 } 1024 1025 static struct i2c_driver dummy_driver = { 1026 .driver.name = "dummy", 1027 .probe = dummy_probe, 1028 .remove = dummy_remove, 1029 .id_table = dummy_id, 1030 }; 1031 1032 /** 1033 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1034 * @adapter: the adapter managing the device 1035 * @address: seven bit address to be used 1036 * Context: can sleep 1037 * 1038 * This returns an I2C client bound to the "dummy" driver, intended for use 1039 * with devices that consume multiple addresses. Examples of such chips 1040 * include various EEPROMS (like 24c04 and 24c08 models). 1041 * 1042 * These dummy devices have two main uses. First, most I2C and SMBus calls 1043 * except i2c_transfer() need a client handle; the dummy will be that handle. 1044 * And second, this prevents the specified address from being bound to a 1045 * different driver. 1046 * 1047 * This returns the new i2c client, which should be saved for later use with 1048 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1049 */ 1050 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address) 1051 { 1052 struct i2c_board_info info = { 1053 I2C_BOARD_INFO("dummy", address), 1054 }; 1055 1056 return i2c_new_client_device(adapter, &info); 1057 } 1058 EXPORT_SYMBOL_GPL(i2c_new_dummy_device); 1059 1060 static void devm_i2c_release_dummy(void *client) 1061 { 1062 i2c_unregister_device(client); 1063 } 1064 1065 /** 1066 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1067 * @dev: device the managed resource is bound to 1068 * @adapter: the adapter managing the device 1069 * @address: seven bit address to be used 1070 * Context: can sleep 1071 * 1072 * This is the device-managed version of @i2c_new_dummy_device. It returns the 1073 * new i2c client or an ERR_PTR in case of an error. 1074 */ 1075 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev, 1076 struct i2c_adapter *adapter, 1077 u16 address) 1078 { 1079 struct i2c_client *client; 1080 int ret; 1081 1082 client = i2c_new_dummy_device(adapter, address); 1083 if (IS_ERR(client)) 1084 return client; 1085 1086 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client); 1087 if (ret) 1088 return ERR_PTR(ret); 1089 1090 return client; 1091 } 1092 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device); 1093 1094 /** 1095 * i2c_new_ancillary_device - Helper to get the instantiated secondary address 1096 * and create the associated device 1097 * @client: Handle to the primary client 1098 * @name: Handle to specify which secondary address to get 1099 * @default_addr: Used as a fallback if no secondary address was specified 1100 * Context: can sleep 1101 * 1102 * I2C clients can be composed of multiple I2C slaves bound together in a single 1103 * component. The I2C client driver then binds to the master I2C slave and needs 1104 * to create I2C dummy clients to communicate with all the other slaves. 1105 * 1106 * This function creates and returns an I2C dummy client whose I2C address is 1107 * retrieved from the platform firmware based on the given slave name. If no 1108 * address is specified by the firmware default_addr is used. 1109 * 1110 * On DT-based platforms the address is retrieved from the "reg" property entry 1111 * cell whose "reg-names" value matches the slave name. 1112 * 1113 * This returns the new i2c client, which should be saved for later use with 1114 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1115 */ 1116 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, 1117 const char *name, 1118 u16 default_addr) 1119 { 1120 struct device_node *np = client->dev.of_node; 1121 u32 addr = default_addr; 1122 int i; 1123 1124 if (np) { 1125 i = of_property_match_string(np, "reg-names", name); 1126 if (i >= 0) 1127 of_property_read_u32_index(np, "reg", i, &addr); 1128 } 1129 1130 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); 1131 return i2c_new_dummy_device(client->adapter, addr); 1132 } 1133 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device); 1134 1135 /* ------------------------------------------------------------------------- */ 1136 1137 /* I2C bus adapters -- one roots each I2C or SMBUS segment */ 1138 1139 static void i2c_adapter_dev_release(struct device *dev) 1140 { 1141 struct i2c_adapter *adap = to_i2c_adapter(dev); 1142 complete(&adap->dev_released); 1143 } 1144 1145 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) 1146 { 1147 unsigned int depth = 0; 1148 1149 while ((adapter = i2c_parent_is_i2c_adapter(adapter))) 1150 depth++; 1151 1152 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES, 1153 "adapter depth exceeds lockdep subclass limit\n"); 1154 1155 return depth; 1156 } 1157 EXPORT_SYMBOL_GPL(i2c_adapter_depth); 1158 1159 /* 1160 * Let users instantiate I2C devices through sysfs. This can be used when 1161 * platform initialization code doesn't contain the proper data for 1162 * whatever reason. Also useful for drivers that do device detection and 1163 * detection fails, either because the device uses an unexpected address, 1164 * or this is a compatible device with different ID register values. 1165 * 1166 * Parameter checking may look overzealous, but we really don't want 1167 * the user to provide incorrect parameters. 1168 */ 1169 static ssize_t 1170 new_device_store(struct device *dev, struct device_attribute *attr, 1171 const char *buf, size_t count) 1172 { 1173 struct i2c_adapter *adap = to_i2c_adapter(dev); 1174 struct i2c_board_info info; 1175 struct i2c_client *client; 1176 char *blank, end; 1177 int res; 1178 1179 memset(&info, 0, sizeof(struct i2c_board_info)); 1180 1181 blank = strchr(buf, ' '); 1182 if (!blank) { 1183 dev_err(dev, "%s: Missing parameters\n", "new_device"); 1184 return -EINVAL; 1185 } 1186 if (blank - buf > I2C_NAME_SIZE - 1) { 1187 dev_err(dev, "%s: Invalid device name\n", "new_device"); 1188 return -EINVAL; 1189 } 1190 memcpy(info.type, buf, blank - buf); 1191 1192 /* Parse remaining parameters, reject extra parameters */ 1193 res = sscanf(++blank, "%hi%c", &info.addr, &end); 1194 if (res < 1) { 1195 dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); 1196 return -EINVAL; 1197 } 1198 if (res > 1 && end != '\n') { 1199 dev_err(dev, "%s: Extra parameters\n", "new_device"); 1200 return -EINVAL; 1201 } 1202 1203 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) { 1204 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT; 1205 info.flags |= I2C_CLIENT_TEN; 1206 } 1207 1208 if (info.addr & I2C_ADDR_OFFSET_SLAVE) { 1209 info.addr &= ~I2C_ADDR_OFFSET_SLAVE; 1210 info.flags |= I2C_CLIENT_SLAVE; 1211 } 1212 1213 client = i2c_new_client_device(adap, &info); 1214 if (IS_ERR(client)) 1215 return PTR_ERR(client); 1216 1217 /* Keep track of the added device */ 1218 mutex_lock(&adap->userspace_clients_lock); 1219 list_add_tail(&client->detected, &adap->userspace_clients); 1220 mutex_unlock(&adap->userspace_clients_lock); 1221 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", 1222 info.type, info.addr); 1223 1224 return count; 1225 } 1226 static DEVICE_ATTR_WO(new_device); 1227 1228 /* 1229 * And of course let the users delete the devices they instantiated, if 1230 * they got it wrong. This interface can only be used to delete devices 1231 * instantiated by i2c_sysfs_new_device above. This guarantees that we 1232 * don't delete devices to which some kernel code still has references. 1233 * 1234 * Parameter checking may look overzealous, but we really don't want 1235 * the user to delete the wrong device. 1236 */ 1237 static ssize_t 1238 delete_device_store(struct device *dev, struct device_attribute *attr, 1239 const char *buf, size_t count) 1240 { 1241 struct i2c_adapter *adap = to_i2c_adapter(dev); 1242 struct i2c_client *client, *next; 1243 unsigned short addr; 1244 char end; 1245 int res; 1246 1247 /* Parse parameters, reject extra parameters */ 1248 res = sscanf(buf, "%hi%c", &addr, &end); 1249 if (res < 1) { 1250 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); 1251 return -EINVAL; 1252 } 1253 if (res > 1 && end != '\n') { 1254 dev_err(dev, "%s: Extra parameters\n", "delete_device"); 1255 return -EINVAL; 1256 } 1257 1258 /* Make sure the device was added through sysfs */ 1259 res = -ENOENT; 1260 mutex_lock_nested(&adap->userspace_clients_lock, 1261 i2c_adapter_depth(adap)); 1262 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1263 detected) { 1264 if (i2c_encode_flags_to_addr(client) == addr) { 1265 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", 1266 "delete_device", client->name, client->addr); 1267 1268 list_del(&client->detected); 1269 i2c_unregister_device(client); 1270 res = count; 1271 break; 1272 } 1273 } 1274 mutex_unlock(&adap->userspace_clients_lock); 1275 1276 if (res < 0) 1277 dev_err(dev, "%s: Can't find device in list\n", 1278 "delete_device"); 1279 return res; 1280 } 1281 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL, 1282 delete_device_store); 1283 1284 static struct attribute *i2c_adapter_attrs[] = { 1285 &dev_attr_name.attr, 1286 &dev_attr_new_device.attr, 1287 &dev_attr_delete_device.attr, 1288 NULL 1289 }; 1290 ATTRIBUTE_GROUPS(i2c_adapter); 1291 1292 struct device_type i2c_adapter_type = { 1293 .groups = i2c_adapter_groups, 1294 .release = i2c_adapter_dev_release, 1295 }; 1296 EXPORT_SYMBOL_GPL(i2c_adapter_type); 1297 1298 /** 1299 * i2c_verify_adapter - return parameter as i2c_adapter or NULL 1300 * @dev: device, probably from some driver model iterator 1301 * 1302 * When traversing the driver model tree, perhaps using driver model 1303 * iterators like @device_for_each_child(), you can't assume very much 1304 * about the nodes you find. Use this function to avoid oopses caused 1305 * by wrongly treating some non-I2C device as an i2c_adapter. 1306 */ 1307 struct i2c_adapter *i2c_verify_adapter(struct device *dev) 1308 { 1309 return (dev->type == &i2c_adapter_type) 1310 ? to_i2c_adapter(dev) 1311 : NULL; 1312 } 1313 EXPORT_SYMBOL(i2c_verify_adapter); 1314 1315 #ifdef CONFIG_I2C_COMPAT 1316 static struct class_compat *i2c_adapter_compat_class; 1317 #endif 1318 1319 static void i2c_scan_static_board_info(struct i2c_adapter *adapter) 1320 { 1321 struct i2c_devinfo *devinfo; 1322 1323 down_read(&__i2c_board_lock); 1324 list_for_each_entry(devinfo, &__i2c_board_list, list) { 1325 if (devinfo->busnum == adapter->nr && 1326 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info))) 1327 dev_err(&adapter->dev, 1328 "Can't create device at 0x%02x\n", 1329 devinfo->board_info.addr); 1330 } 1331 up_read(&__i2c_board_lock); 1332 } 1333 1334 static int i2c_do_add_adapter(struct i2c_driver *driver, 1335 struct i2c_adapter *adap) 1336 { 1337 /* Detect supported devices on that bus, and instantiate them */ 1338 i2c_detect(adap, driver); 1339 1340 return 0; 1341 } 1342 1343 static int __process_new_adapter(struct device_driver *d, void *data) 1344 { 1345 return i2c_do_add_adapter(to_i2c_driver(d), data); 1346 } 1347 1348 static const struct i2c_lock_operations i2c_adapter_lock_ops = { 1349 .lock_bus = i2c_adapter_lock_bus, 1350 .trylock_bus = i2c_adapter_trylock_bus, 1351 .unlock_bus = i2c_adapter_unlock_bus, 1352 }; 1353 1354 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap) 1355 { 1356 struct irq_domain *domain = adap->host_notify_domain; 1357 irq_hw_number_t hwirq; 1358 1359 if (!domain) 1360 return; 1361 1362 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++) 1363 irq_dispose_mapping(irq_find_mapping(domain, hwirq)); 1364 1365 irq_domain_remove(domain); 1366 adap->host_notify_domain = NULL; 1367 } 1368 1369 static int i2c_host_notify_irq_map(struct irq_domain *h, 1370 unsigned int virq, 1371 irq_hw_number_t hw_irq_num) 1372 { 1373 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq); 1374 1375 return 0; 1376 } 1377 1378 static const struct irq_domain_ops i2c_host_notify_irq_ops = { 1379 .map = i2c_host_notify_irq_map, 1380 }; 1381 1382 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap) 1383 { 1384 struct irq_domain *domain; 1385 1386 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY)) 1387 return 0; 1388 1389 domain = irq_domain_create_linear(adap->dev.parent->fwnode, 1390 I2C_ADDR_7BITS_COUNT, 1391 &i2c_host_notify_irq_ops, adap); 1392 if (!domain) 1393 return -ENOMEM; 1394 1395 adap->host_notify_domain = domain; 1396 1397 return 0; 1398 } 1399 1400 /** 1401 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct 1402 * I2C client. 1403 * @adap: the adapter 1404 * @addr: the I2C address of the notifying device 1405 * Context: can't sleep 1406 * 1407 * Helper function to be called from an I2C bus driver's interrupt 1408 * handler. It will schedule the Host Notify IRQ. 1409 */ 1410 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr) 1411 { 1412 int irq; 1413 1414 if (!adap) 1415 return -EINVAL; 1416 1417 irq = irq_find_mapping(adap->host_notify_domain, addr); 1418 if (irq <= 0) 1419 return -ENXIO; 1420 1421 generic_handle_irq(irq); 1422 1423 return 0; 1424 } 1425 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify); 1426 1427 static int i2c_register_adapter(struct i2c_adapter *adap) 1428 { 1429 int res = -EINVAL; 1430 1431 /* Can't register until after driver model init */ 1432 if (WARN_ON(!is_registered)) { 1433 res = -EAGAIN; 1434 goto out_list; 1435 } 1436 1437 /* Sanity checks */ 1438 if (WARN(!adap->name[0], "i2c adapter has no name")) 1439 goto out_list; 1440 1441 if (!adap->algo) { 1442 pr_err("adapter '%s': no algo supplied!\n", adap->name); 1443 goto out_list; 1444 } 1445 1446 if (!adap->lock_ops) 1447 adap->lock_ops = &i2c_adapter_lock_ops; 1448 1449 adap->locked_flags = 0; 1450 rt_mutex_init(&adap->bus_lock); 1451 rt_mutex_init(&adap->mux_lock); 1452 mutex_init(&adap->userspace_clients_lock); 1453 INIT_LIST_HEAD(&adap->userspace_clients); 1454 1455 /* Set default timeout to 1 second if not already set */ 1456 if (adap->timeout == 0) 1457 adap->timeout = HZ; 1458 1459 /* register soft irqs for Host Notify */ 1460 res = i2c_setup_host_notify_irq_domain(adap); 1461 if (res) { 1462 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n", 1463 adap->name, res); 1464 goto out_list; 1465 } 1466 1467 dev_set_name(&adap->dev, "i2c-%d", adap->nr); 1468 adap->dev.bus = &i2c_bus_type; 1469 adap->dev.type = &i2c_adapter_type; 1470 res = device_register(&adap->dev); 1471 if (res) { 1472 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); 1473 goto out_list; 1474 } 1475 1476 res = of_i2c_setup_smbus_alert(adap); 1477 if (res) 1478 goto out_reg; 1479 1480 pm_runtime_no_callbacks(&adap->dev); 1481 pm_suspend_ignore_children(&adap->dev, true); 1482 pm_runtime_enable(&adap->dev); 1483 1484 res = i2c_init_recovery(adap); 1485 if (res == -EPROBE_DEFER) 1486 goto out_reg; 1487 1488 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); 1489 1490 #ifdef CONFIG_I2C_COMPAT 1491 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, 1492 adap->dev.parent); 1493 if (res) 1494 dev_warn(&adap->dev, 1495 "Failed to create compatibility class link\n"); 1496 #endif 1497 1498 /* create pre-declared device nodes */ 1499 of_i2c_register_devices(adap); 1500 i2c_acpi_install_space_handler(adap); 1501 i2c_acpi_register_devices(adap); 1502 1503 if (adap->nr < __i2c_first_dynamic_bus_num) 1504 i2c_scan_static_board_info(adap); 1505 1506 /* Notify drivers */ 1507 mutex_lock(&core_lock); 1508 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); 1509 mutex_unlock(&core_lock); 1510 1511 return 0; 1512 1513 out_reg: 1514 init_completion(&adap->dev_released); 1515 device_unregister(&adap->dev); 1516 wait_for_completion(&adap->dev_released); 1517 out_list: 1518 mutex_lock(&core_lock); 1519 idr_remove(&i2c_adapter_idr, adap->nr); 1520 mutex_unlock(&core_lock); 1521 return res; 1522 } 1523 1524 /** 1525 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 1526 * @adap: the adapter to register (with adap->nr initialized) 1527 * Context: can sleep 1528 * 1529 * See i2c_add_numbered_adapter() for details. 1530 */ 1531 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) 1532 { 1533 int id; 1534 1535 mutex_lock(&core_lock); 1536 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); 1537 mutex_unlock(&core_lock); 1538 if (WARN(id < 0, "couldn't get idr")) 1539 return id == -ENOSPC ? -EBUSY : id; 1540 1541 return i2c_register_adapter(adap); 1542 } 1543 1544 /** 1545 * i2c_add_adapter - declare i2c adapter, use dynamic bus number 1546 * @adapter: the adapter to add 1547 * Context: can sleep 1548 * 1549 * This routine is used to declare an I2C adapter when its bus number 1550 * doesn't matter or when its bus number is specified by an dt alias. 1551 * Examples of bases when the bus number doesn't matter: I2C adapters 1552 * dynamically added by USB links or PCI plugin cards. 1553 * 1554 * When this returns zero, a new bus number was allocated and stored 1555 * in adap->nr, and the specified adapter became available for clients. 1556 * Otherwise, a negative errno value is returned. 1557 */ 1558 int i2c_add_adapter(struct i2c_adapter *adapter) 1559 { 1560 struct device *dev = &adapter->dev; 1561 int id; 1562 1563 if (dev->of_node) { 1564 id = of_alias_get_id(dev->of_node, "i2c"); 1565 if (id >= 0) { 1566 adapter->nr = id; 1567 return __i2c_add_numbered_adapter(adapter); 1568 } 1569 } 1570 1571 mutex_lock(&core_lock); 1572 id = idr_alloc(&i2c_adapter_idr, adapter, 1573 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); 1574 mutex_unlock(&core_lock); 1575 if (WARN(id < 0, "couldn't get idr")) 1576 return id; 1577 1578 adapter->nr = id; 1579 1580 return i2c_register_adapter(adapter); 1581 } 1582 EXPORT_SYMBOL(i2c_add_adapter); 1583 1584 /** 1585 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number 1586 * @adap: the adapter to register (with adap->nr initialized) 1587 * Context: can sleep 1588 * 1589 * This routine is used to declare an I2C adapter when its bus number 1590 * matters. For example, use it for I2C adapters from system-on-chip CPUs, 1591 * or otherwise built in to the system's mainboard, and where i2c_board_info 1592 * is used to properly configure I2C devices. 1593 * 1594 * If the requested bus number is set to -1, then this function will behave 1595 * identically to i2c_add_adapter, and will dynamically assign a bus number. 1596 * 1597 * If no devices have pre-been declared for this bus, then be sure to 1598 * register the adapter before any dynamically allocated ones. Otherwise 1599 * the required bus ID may not be available. 1600 * 1601 * When this returns zero, the specified adapter became available for 1602 * clients using the bus number provided in adap->nr. Also, the table 1603 * of I2C devices pre-declared using i2c_register_board_info() is scanned, 1604 * and the appropriate driver model device nodes are created. Otherwise, a 1605 * negative errno value is returned. 1606 */ 1607 int i2c_add_numbered_adapter(struct i2c_adapter *adap) 1608 { 1609 if (adap->nr == -1) /* -1 means dynamically assign bus id */ 1610 return i2c_add_adapter(adap); 1611 1612 return __i2c_add_numbered_adapter(adap); 1613 } 1614 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); 1615 1616 static void i2c_do_del_adapter(struct i2c_driver *driver, 1617 struct i2c_adapter *adapter) 1618 { 1619 struct i2c_client *client, *_n; 1620 1621 /* Remove the devices we created ourselves as the result of hardware 1622 * probing (using a driver's detect method) */ 1623 list_for_each_entry_safe(client, _n, &driver->clients, detected) { 1624 if (client->adapter == adapter) { 1625 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", 1626 client->name, client->addr); 1627 list_del(&client->detected); 1628 i2c_unregister_device(client); 1629 } 1630 } 1631 } 1632 1633 static int __unregister_client(struct device *dev, void *dummy) 1634 { 1635 struct i2c_client *client = i2c_verify_client(dev); 1636 if (client && strcmp(client->name, "dummy")) 1637 i2c_unregister_device(client); 1638 return 0; 1639 } 1640 1641 static int __unregister_dummy(struct device *dev, void *dummy) 1642 { 1643 struct i2c_client *client = i2c_verify_client(dev); 1644 i2c_unregister_device(client); 1645 return 0; 1646 } 1647 1648 static int __process_removed_adapter(struct device_driver *d, void *data) 1649 { 1650 i2c_do_del_adapter(to_i2c_driver(d), data); 1651 return 0; 1652 } 1653 1654 /** 1655 * i2c_del_adapter - unregister I2C adapter 1656 * @adap: the adapter being unregistered 1657 * Context: can sleep 1658 * 1659 * This unregisters an I2C adapter which was previously registered 1660 * by @i2c_add_adapter or @i2c_add_numbered_adapter. 1661 */ 1662 void i2c_del_adapter(struct i2c_adapter *adap) 1663 { 1664 struct i2c_adapter *found; 1665 struct i2c_client *client, *next; 1666 1667 /* First make sure that this adapter was ever added */ 1668 mutex_lock(&core_lock); 1669 found = idr_find(&i2c_adapter_idr, adap->nr); 1670 mutex_unlock(&core_lock); 1671 if (found != adap) { 1672 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); 1673 return; 1674 } 1675 1676 i2c_acpi_remove_space_handler(adap); 1677 /* Tell drivers about this removal */ 1678 mutex_lock(&core_lock); 1679 bus_for_each_drv(&i2c_bus_type, NULL, adap, 1680 __process_removed_adapter); 1681 mutex_unlock(&core_lock); 1682 1683 /* Remove devices instantiated from sysfs */ 1684 mutex_lock_nested(&adap->userspace_clients_lock, 1685 i2c_adapter_depth(adap)); 1686 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1687 detected) { 1688 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, 1689 client->addr); 1690 list_del(&client->detected); 1691 i2c_unregister_device(client); 1692 } 1693 mutex_unlock(&adap->userspace_clients_lock); 1694 1695 /* Detach any active clients. This can't fail, thus we do not 1696 * check the returned value. This is a two-pass process, because 1697 * we can't remove the dummy devices during the first pass: they 1698 * could have been instantiated by real devices wishing to clean 1699 * them up properly, so we give them a chance to do that first. */ 1700 device_for_each_child(&adap->dev, NULL, __unregister_client); 1701 device_for_each_child(&adap->dev, NULL, __unregister_dummy); 1702 1703 #ifdef CONFIG_I2C_COMPAT 1704 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, 1705 adap->dev.parent); 1706 #endif 1707 1708 /* device name is gone after device_unregister */ 1709 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); 1710 1711 pm_runtime_disable(&adap->dev); 1712 1713 i2c_host_notify_irq_teardown(adap); 1714 1715 /* wait until all references to the device are gone 1716 * 1717 * FIXME: This is old code and should ideally be replaced by an 1718 * alternative which results in decoupling the lifetime of the struct 1719 * device from the i2c_adapter, like spi or netdev do. Any solution 1720 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled! 1721 */ 1722 init_completion(&adap->dev_released); 1723 device_unregister(&adap->dev); 1724 wait_for_completion(&adap->dev_released); 1725 1726 /* free bus id */ 1727 mutex_lock(&core_lock); 1728 idr_remove(&i2c_adapter_idr, adap->nr); 1729 mutex_unlock(&core_lock); 1730 1731 /* Clear the device structure in case this adapter is ever going to be 1732 added again */ 1733 memset(&adap->dev, 0, sizeof(adap->dev)); 1734 } 1735 EXPORT_SYMBOL(i2c_del_adapter); 1736 1737 static void devm_i2c_del_adapter(void *adapter) 1738 { 1739 i2c_del_adapter(adapter); 1740 } 1741 1742 /** 1743 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter() 1744 * @dev: managing device for adding this I2C adapter 1745 * @adapter: the adapter to add 1746 * Context: can sleep 1747 * 1748 * Add adapter with dynamic bus number, same with i2c_add_adapter() 1749 * but the adapter will be auto deleted on driver detach. 1750 */ 1751 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter) 1752 { 1753 int ret; 1754 1755 ret = i2c_add_adapter(adapter); 1756 if (ret) 1757 return ret; 1758 1759 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter); 1760 } 1761 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter); 1762 1763 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p, 1764 u32 def_val, bool use_def) 1765 { 1766 int ret; 1767 1768 ret = device_property_read_u32(dev, prop_name, cur_val_p); 1769 if (ret && use_def) 1770 *cur_val_p = def_val; 1771 1772 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p); 1773 } 1774 1775 /** 1776 * i2c_parse_fw_timings - get I2C related timing parameters from firmware 1777 * @dev: The device to scan for I2C timing properties 1778 * @t: the i2c_timings struct to be filled with values 1779 * @use_defaults: bool to use sane defaults derived from the I2C specification 1780 * when properties are not found, otherwise don't update 1781 * 1782 * Scan the device for the generic I2C properties describing timing parameters 1783 * for the signal and fill the given struct with the results. If a property was 1784 * not found and use_defaults was true, then maximum timings are assumed which 1785 * are derived from the I2C specification. If use_defaults is not used, the 1786 * results will be as before, so drivers can apply their own defaults before 1787 * calling this helper. The latter is mainly intended for avoiding regressions 1788 * of existing drivers which want to switch to this function. New drivers 1789 * almost always should use the defaults. 1790 */ 1791 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) 1792 { 1793 bool u = use_defaults; 1794 u32 d; 1795 1796 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz, 1797 I2C_MAX_STANDARD_MODE_FREQ, u); 1798 1799 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 : 1800 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1801 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u); 1802 1803 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1804 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u); 1805 1806 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns", 1807 &t->scl_int_delay_ns, 0, u); 1808 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns, 1809 t->scl_fall_ns, u); 1810 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u); 1811 i2c_parse_timing(dev, "i2c-digital-filter-width-ns", 1812 &t->digital_filter_width_ns, 0, u); 1813 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency", 1814 &t->analog_filter_cutoff_freq_hz, 0, u); 1815 } 1816 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); 1817 1818 /* ------------------------------------------------------------------------- */ 1819 1820 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data)) 1821 { 1822 int res; 1823 1824 mutex_lock(&core_lock); 1825 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn); 1826 mutex_unlock(&core_lock); 1827 1828 return res; 1829 } 1830 EXPORT_SYMBOL_GPL(i2c_for_each_dev); 1831 1832 static int __process_new_driver(struct device *dev, void *data) 1833 { 1834 if (dev->type != &i2c_adapter_type) 1835 return 0; 1836 return i2c_do_add_adapter(data, to_i2c_adapter(dev)); 1837 } 1838 1839 /* 1840 * An i2c_driver is used with one or more i2c_client (device) nodes to access 1841 * i2c slave chips, on a bus instance associated with some i2c_adapter. 1842 */ 1843 1844 int i2c_register_driver(struct module *owner, struct i2c_driver *driver) 1845 { 1846 int res; 1847 1848 /* Can't register until after driver model init */ 1849 if (WARN_ON(!is_registered)) 1850 return -EAGAIN; 1851 1852 /* add the driver to the list of i2c drivers in the driver core */ 1853 driver->driver.owner = owner; 1854 driver->driver.bus = &i2c_bus_type; 1855 INIT_LIST_HEAD(&driver->clients); 1856 1857 /* When registration returns, the driver core 1858 * will have called probe() for all matching-but-unbound devices. 1859 */ 1860 res = driver_register(&driver->driver); 1861 if (res) 1862 return res; 1863 1864 pr_debug("driver [%s] registered\n", driver->driver.name); 1865 1866 /* Walk the adapters that are already present */ 1867 i2c_for_each_dev(driver, __process_new_driver); 1868 1869 return 0; 1870 } 1871 EXPORT_SYMBOL(i2c_register_driver); 1872 1873 static int __process_removed_driver(struct device *dev, void *data) 1874 { 1875 if (dev->type == &i2c_adapter_type) 1876 i2c_do_del_adapter(data, to_i2c_adapter(dev)); 1877 return 0; 1878 } 1879 1880 /** 1881 * i2c_del_driver - unregister I2C driver 1882 * @driver: the driver being unregistered 1883 * Context: can sleep 1884 */ 1885 void i2c_del_driver(struct i2c_driver *driver) 1886 { 1887 i2c_for_each_dev(driver, __process_removed_driver); 1888 1889 driver_unregister(&driver->driver); 1890 pr_debug("driver [%s] unregistered\n", driver->driver.name); 1891 } 1892 EXPORT_SYMBOL(i2c_del_driver); 1893 1894 /* ------------------------------------------------------------------------- */ 1895 1896 struct i2c_cmd_arg { 1897 unsigned cmd; 1898 void *arg; 1899 }; 1900 1901 static int i2c_cmd(struct device *dev, void *_arg) 1902 { 1903 struct i2c_client *client = i2c_verify_client(dev); 1904 struct i2c_cmd_arg *arg = _arg; 1905 struct i2c_driver *driver; 1906 1907 if (!client || !client->dev.driver) 1908 return 0; 1909 1910 driver = to_i2c_driver(client->dev.driver); 1911 if (driver->command) 1912 driver->command(client, arg->cmd, arg->arg); 1913 return 0; 1914 } 1915 1916 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) 1917 { 1918 struct i2c_cmd_arg cmd_arg; 1919 1920 cmd_arg.cmd = cmd; 1921 cmd_arg.arg = arg; 1922 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); 1923 } 1924 EXPORT_SYMBOL(i2c_clients_command); 1925 1926 static int __init i2c_init(void) 1927 { 1928 int retval; 1929 1930 retval = of_alias_get_highest_id("i2c"); 1931 1932 down_write(&__i2c_board_lock); 1933 if (retval >= __i2c_first_dynamic_bus_num) 1934 __i2c_first_dynamic_bus_num = retval + 1; 1935 up_write(&__i2c_board_lock); 1936 1937 retval = bus_register(&i2c_bus_type); 1938 if (retval) 1939 return retval; 1940 1941 is_registered = true; 1942 1943 #ifdef CONFIG_I2C_COMPAT 1944 i2c_adapter_compat_class = class_compat_register("i2c-adapter"); 1945 if (!i2c_adapter_compat_class) { 1946 retval = -ENOMEM; 1947 goto bus_err; 1948 } 1949 #endif 1950 retval = i2c_add_driver(&dummy_driver); 1951 if (retval) 1952 goto class_err; 1953 1954 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 1955 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); 1956 if (IS_ENABLED(CONFIG_ACPI)) 1957 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier)); 1958 1959 return 0; 1960 1961 class_err: 1962 #ifdef CONFIG_I2C_COMPAT 1963 class_compat_unregister(i2c_adapter_compat_class); 1964 bus_err: 1965 #endif 1966 is_registered = false; 1967 bus_unregister(&i2c_bus_type); 1968 return retval; 1969 } 1970 1971 static void __exit i2c_exit(void) 1972 { 1973 if (IS_ENABLED(CONFIG_ACPI)) 1974 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier)); 1975 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 1976 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier)); 1977 i2c_del_driver(&dummy_driver); 1978 #ifdef CONFIG_I2C_COMPAT 1979 class_compat_unregister(i2c_adapter_compat_class); 1980 #endif 1981 bus_unregister(&i2c_bus_type); 1982 tracepoint_synchronize_unregister(); 1983 } 1984 1985 /* We must initialize early, because some subsystems register i2c drivers 1986 * in subsys_initcall() code, but are linked (and initialized) before i2c. 1987 */ 1988 postcore_initcall(i2c_init); 1989 module_exit(i2c_exit); 1990 1991 /* ---------------------------------------------------- 1992 * the functional interface to the i2c busses. 1993 * ---------------------------------------------------- 1994 */ 1995 1996 /* Check if val is exceeding the quirk IFF quirk is non 0 */ 1997 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) 1998 1999 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) 2000 { 2001 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n", 2002 err_msg, msg->addr, msg->len, 2003 msg->flags & I2C_M_RD ? "read" : "write"); 2004 return -EOPNOTSUPP; 2005 } 2006 2007 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2008 { 2009 const struct i2c_adapter_quirks *q = adap->quirks; 2010 int max_num = q->max_num_msgs, i; 2011 bool do_len_check = true; 2012 2013 if (q->flags & I2C_AQ_COMB) { 2014 max_num = 2; 2015 2016 /* special checks for combined messages */ 2017 if (num == 2) { 2018 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD) 2019 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write"); 2020 2021 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD)) 2022 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read"); 2023 2024 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr) 2025 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr"); 2026 2027 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len)) 2028 return i2c_quirk_error(adap, &msgs[0], "msg too long"); 2029 2030 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len)) 2031 return i2c_quirk_error(adap, &msgs[1], "msg too long"); 2032 2033 do_len_check = false; 2034 } 2035 } 2036 2037 if (i2c_quirk_exceeded(num, max_num)) 2038 return i2c_quirk_error(adap, &msgs[0], "too many messages"); 2039 2040 for (i = 0; i < num; i++) { 2041 u16 len = msgs[i].len; 2042 2043 if (msgs[i].flags & I2C_M_RD) { 2044 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len)) 2045 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2046 2047 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0) 2048 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2049 } else { 2050 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len)) 2051 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2052 2053 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0) 2054 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2055 } 2056 } 2057 2058 return 0; 2059 } 2060 2061 /** 2062 * __i2c_transfer - unlocked flavor of i2c_transfer 2063 * @adap: Handle to I2C bus 2064 * @msgs: One or more messages to execute before STOP is issued to 2065 * terminate the operation; each message begins with a START. 2066 * @num: Number of messages to be executed. 2067 * 2068 * Returns negative errno, else the number of messages executed. 2069 * 2070 * Adapter lock must be held when calling this function. No debug logging 2071 * takes place. adap->algo->master_xfer existence isn't checked. 2072 */ 2073 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2074 { 2075 unsigned long orig_jiffies; 2076 int ret, try; 2077 2078 if (WARN_ON(!msgs || num < 1)) 2079 return -EINVAL; 2080 2081 ret = __i2c_check_suspended(adap); 2082 if (ret) 2083 return ret; 2084 2085 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) 2086 return -EOPNOTSUPP; 2087 2088 /* 2089 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets 2090 * enabled. This is an efficient way of keeping the for-loop from 2091 * being executed when not needed. 2092 */ 2093 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2094 int i; 2095 for (i = 0; i < num; i++) 2096 if (msgs[i].flags & I2C_M_RD) 2097 trace_i2c_read(adap, &msgs[i], i); 2098 else 2099 trace_i2c_write(adap, &msgs[i], i); 2100 } 2101 2102 /* Retry automatically on arbitration loss */ 2103 orig_jiffies = jiffies; 2104 for (ret = 0, try = 0; try <= adap->retries; try++) { 2105 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic) 2106 ret = adap->algo->master_xfer_atomic(adap, msgs, num); 2107 else 2108 ret = adap->algo->master_xfer(adap, msgs, num); 2109 2110 if (ret != -EAGAIN) 2111 break; 2112 if (time_after(jiffies, orig_jiffies + adap->timeout)) 2113 break; 2114 } 2115 2116 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2117 int i; 2118 for (i = 0; i < ret; i++) 2119 if (msgs[i].flags & I2C_M_RD) 2120 trace_i2c_reply(adap, &msgs[i], i); 2121 trace_i2c_result(adap, num, ret); 2122 } 2123 2124 return ret; 2125 } 2126 EXPORT_SYMBOL(__i2c_transfer); 2127 2128 /** 2129 * i2c_transfer - execute a single or combined I2C message 2130 * @adap: Handle to I2C bus 2131 * @msgs: One or more messages to execute before STOP is issued to 2132 * terminate the operation; each message begins with a START. 2133 * @num: Number of messages to be executed. 2134 * 2135 * Returns negative errno, else the number of messages executed. 2136 * 2137 * Note that there is no requirement that each message be sent to 2138 * the same slave address, although that is the most common model. 2139 */ 2140 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2141 { 2142 int ret; 2143 2144 if (!adap->algo->master_xfer) { 2145 dev_dbg(&adap->dev, "I2C level transfers not supported\n"); 2146 return -EOPNOTSUPP; 2147 } 2148 2149 /* REVISIT the fault reporting model here is weak: 2150 * 2151 * - When we get an error after receiving N bytes from a slave, 2152 * there is no way to report "N". 2153 * 2154 * - When we get a NAK after transmitting N bytes to a slave, 2155 * there is no way to report "N" ... or to let the master 2156 * continue executing the rest of this combined message, if 2157 * that's the appropriate response. 2158 * 2159 * - When for example "num" is two and we successfully complete 2160 * the first message but get an error part way through the 2161 * second, it's unclear whether that should be reported as 2162 * one (discarding status on the second message) or errno 2163 * (discarding status on the first one). 2164 */ 2165 ret = __i2c_lock_bus_helper(adap); 2166 if (ret) 2167 return ret; 2168 2169 ret = __i2c_transfer(adap, msgs, num); 2170 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); 2171 2172 return ret; 2173 } 2174 EXPORT_SYMBOL(i2c_transfer); 2175 2176 /** 2177 * i2c_transfer_buffer_flags - issue a single I2C message transferring data 2178 * to/from a buffer 2179 * @client: Handle to slave device 2180 * @buf: Where the data is stored 2181 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16 2182 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads 2183 * 2184 * Returns negative errno, or else the number of bytes transferred. 2185 */ 2186 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf, 2187 int count, u16 flags) 2188 { 2189 int ret; 2190 struct i2c_msg msg = { 2191 .addr = client->addr, 2192 .flags = flags | (client->flags & I2C_M_TEN), 2193 .len = count, 2194 .buf = buf, 2195 }; 2196 2197 ret = i2c_transfer(client->adapter, &msg, 1); 2198 2199 /* 2200 * If everything went ok (i.e. 1 msg transferred), return #bytes 2201 * transferred, else error code. 2202 */ 2203 return (ret == 1) ? count : ret; 2204 } 2205 EXPORT_SYMBOL(i2c_transfer_buffer_flags); 2206 2207 /** 2208 * i2c_get_device_id - get manufacturer, part id and die revision of a device 2209 * @client: The device to query 2210 * @id: The queried information 2211 * 2212 * Returns negative errno on error, zero on success. 2213 */ 2214 int i2c_get_device_id(const struct i2c_client *client, 2215 struct i2c_device_identity *id) 2216 { 2217 struct i2c_adapter *adap = client->adapter; 2218 union i2c_smbus_data raw_id; 2219 int ret; 2220 2221 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) 2222 return -EOPNOTSUPP; 2223 2224 raw_id.block[0] = 3; 2225 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0, 2226 I2C_SMBUS_READ, client->addr << 1, 2227 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id); 2228 if (ret) 2229 return ret; 2230 2231 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4); 2232 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3); 2233 id->die_revision = raw_id.block[3] & 0x7; 2234 return 0; 2235 } 2236 EXPORT_SYMBOL_GPL(i2c_get_device_id); 2237 2238 /* ---------------------------------------------------- 2239 * the i2c address scanning function 2240 * Will not work for 10-bit addresses! 2241 * ---------------------------------------------------- 2242 */ 2243 2244 /* 2245 * Legacy default probe function, mostly relevant for SMBus. The default 2246 * probe method is a quick write, but it is known to corrupt the 24RF08 2247 * EEPROMs due to a state machine bug, and could also irreversibly 2248 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f, 2249 * we use a short byte read instead. Also, some bus drivers don't implement 2250 * quick write, so we fallback to a byte read in that case too. 2251 * On x86, there is another special case for FSC hardware monitoring chips, 2252 * which want regular byte reads (address 0x73.) Fortunately, these are the 2253 * only known chips using this I2C address on PC hardware. 2254 * Returns 1 if probe succeeded, 0 if not. 2255 */ 2256 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) 2257 { 2258 int err; 2259 union i2c_smbus_data dummy; 2260 2261 #ifdef CONFIG_X86 2262 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON) 2263 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA)) 2264 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2265 I2C_SMBUS_BYTE_DATA, &dummy); 2266 else 2267 #endif 2268 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) 2269 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) 2270 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, 2271 I2C_SMBUS_QUICK, NULL); 2272 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) 2273 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2274 I2C_SMBUS_BYTE, &dummy); 2275 else { 2276 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n", 2277 addr); 2278 err = -EOPNOTSUPP; 2279 } 2280 2281 return err >= 0; 2282 } 2283 2284 static int i2c_detect_address(struct i2c_client *temp_client, 2285 struct i2c_driver *driver) 2286 { 2287 struct i2c_board_info info; 2288 struct i2c_adapter *adapter = temp_client->adapter; 2289 int addr = temp_client->addr; 2290 int err; 2291 2292 /* Make sure the address is valid */ 2293 err = i2c_check_7bit_addr_validity_strict(addr); 2294 if (err) { 2295 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n", 2296 addr); 2297 return err; 2298 } 2299 2300 /* Skip if already in use (7 bit, no need to encode flags) */ 2301 if (i2c_check_addr_busy(adapter, addr)) 2302 return 0; 2303 2304 /* Make sure there is something at this address */ 2305 if (!i2c_default_probe(adapter, addr)) 2306 return 0; 2307 2308 /* Finally call the custom detection function */ 2309 memset(&info, 0, sizeof(struct i2c_board_info)); 2310 info.addr = addr; 2311 err = driver->detect(temp_client, &info); 2312 if (err) { 2313 /* -ENODEV is returned if the detection fails. We catch it 2314 here as this isn't an error. */ 2315 return err == -ENODEV ? 0 : err; 2316 } 2317 2318 /* Consistency check */ 2319 if (info.type[0] == '\0') { 2320 dev_err(&adapter->dev, 2321 "%s detection function provided no name for 0x%x\n", 2322 driver->driver.name, addr); 2323 } else { 2324 struct i2c_client *client; 2325 2326 /* Detection succeeded, instantiate the device */ 2327 if (adapter->class & I2C_CLASS_DEPRECATED) 2328 dev_warn(&adapter->dev, 2329 "This adapter will soon drop class based instantiation of devices. " 2330 "Please make sure client 0x%02x gets instantiated by other means. " 2331 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n", 2332 info.addr); 2333 2334 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n", 2335 info.type, info.addr); 2336 client = i2c_new_client_device(adapter, &info); 2337 if (!IS_ERR(client)) 2338 list_add_tail(&client->detected, &driver->clients); 2339 else 2340 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n", 2341 info.type, info.addr); 2342 } 2343 return 0; 2344 } 2345 2346 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) 2347 { 2348 const unsigned short *address_list; 2349 struct i2c_client *temp_client; 2350 int i, err = 0; 2351 2352 address_list = driver->address_list; 2353 if (!driver->detect || !address_list) 2354 return 0; 2355 2356 /* Warn that the adapter lost class based instantiation */ 2357 if (adapter->class == I2C_CLASS_DEPRECATED) { 2358 dev_dbg(&adapter->dev, 2359 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. " 2360 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n", 2361 driver->driver.name); 2362 return 0; 2363 } 2364 2365 /* Stop here if the classes do not match */ 2366 if (!(adapter->class & driver->class)) 2367 return 0; 2368 2369 /* Set up a temporary client to help detect callback */ 2370 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); 2371 if (!temp_client) 2372 return -ENOMEM; 2373 temp_client->adapter = adapter; 2374 2375 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { 2376 dev_dbg(&adapter->dev, 2377 "found normal entry for adapter %d, addr 0x%02x\n", 2378 i2c_adapter_id(adapter), address_list[i]); 2379 temp_client->addr = address_list[i]; 2380 err = i2c_detect_address(temp_client, driver); 2381 if (unlikely(err)) 2382 break; 2383 } 2384 2385 kfree(temp_client); 2386 return err; 2387 } 2388 2389 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) 2390 { 2391 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2392 I2C_SMBUS_QUICK, NULL) >= 0; 2393 } 2394 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); 2395 2396 struct i2c_client * 2397 i2c_new_scanned_device(struct i2c_adapter *adap, 2398 struct i2c_board_info *info, 2399 unsigned short const *addr_list, 2400 int (*probe)(struct i2c_adapter *adap, unsigned short addr)) 2401 { 2402 int i; 2403 2404 if (!probe) 2405 probe = i2c_default_probe; 2406 2407 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { 2408 /* Check address validity */ 2409 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) { 2410 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n", 2411 addr_list[i]); 2412 continue; 2413 } 2414 2415 /* Check address availability (7 bit, no need to encode flags) */ 2416 if (i2c_check_addr_busy(adap, addr_list[i])) { 2417 dev_dbg(&adap->dev, 2418 "Address 0x%02x already in use, not probing\n", 2419 addr_list[i]); 2420 continue; 2421 } 2422 2423 /* Test address responsiveness */ 2424 if (probe(adap, addr_list[i])) 2425 break; 2426 } 2427 2428 if (addr_list[i] == I2C_CLIENT_END) { 2429 dev_dbg(&adap->dev, "Probing failed, no device found\n"); 2430 return ERR_PTR(-ENODEV); 2431 } 2432 2433 info->addr = addr_list[i]; 2434 return i2c_new_client_device(adap, info); 2435 } 2436 EXPORT_SYMBOL_GPL(i2c_new_scanned_device); 2437 2438 struct i2c_adapter *i2c_get_adapter(int nr) 2439 { 2440 struct i2c_adapter *adapter; 2441 2442 mutex_lock(&core_lock); 2443 adapter = idr_find(&i2c_adapter_idr, nr); 2444 if (!adapter) 2445 goto exit; 2446 2447 if (try_module_get(adapter->owner)) 2448 get_device(&adapter->dev); 2449 else 2450 adapter = NULL; 2451 2452 exit: 2453 mutex_unlock(&core_lock); 2454 return adapter; 2455 } 2456 EXPORT_SYMBOL(i2c_get_adapter); 2457 2458 void i2c_put_adapter(struct i2c_adapter *adap) 2459 { 2460 if (!adap) 2461 return; 2462 2463 put_device(&adap->dev); 2464 module_put(adap->owner); 2465 } 2466 EXPORT_SYMBOL(i2c_put_adapter); 2467 2468 /** 2469 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg 2470 * @msg: the message to be checked 2471 * @threshold: the minimum number of bytes for which using DMA makes sense. 2472 * Should at least be 1. 2473 * 2474 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO. 2475 * Or a valid pointer to be used with DMA. After use, release it by 2476 * calling i2c_put_dma_safe_msg_buf(). 2477 * 2478 * This function must only be called from process context! 2479 */ 2480 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold) 2481 { 2482 /* also skip 0-length msgs for bogus thresholds of 0 */ 2483 if (!threshold) 2484 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n", 2485 msg->addr); 2486 if (msg->len < threshold || msg->len == 0) 2487 return NULL; 2488 2489 if (msg->flags & I2C_M_DMA_SAFE) 2490 return msg->buf; 2491 2492 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n", 2493 msg->addr, msg->len); 2494 2495 if (msg->flags & I2C_M_RD) 2496 return kzalloc(msg->len, GFP_KERNEL); 2497 else 2498 return kmemdup(msg->buf, msg->len, GFP_KERNEL); 2499 } 2500 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf); 2501 2502 /** 2503 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg 2504 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL. 2505 * @msg: the message which the buffer corresponds to 2506 * @xferred: bool saying if the message was transferred 2507 */ 2508 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred) 2509 { 2510 if (!buf || buf == msg->buf) 2511 return; 2512 2513 if (xferred && msg->flags & I2C_M_RD) 2514 memcpy(msg->buf, buf, msg->len); 2515 2516 kfree(buf); 2517 } 2518 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf); 2519 2520 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 2521 MODULE_DESCRIPTION("I2C-Bus main module"); 2522 MODULE_LICENSE("GPL"); 2523