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/interrupt.h> 28 #include <linux/irqflags.h> 29 #include <linux/jump_label.h> 30 #include <linux/kernel.h> 31 #include <linux/module.h> 32 #include <linux/mutex.h> 33 #include <linux/of_device.h> 34 #include <linux/of.h> 35 #include <linux/of_irq.h> 36 #include <linux/pinctrl/consumer.h> 37 #include <linux/pm_domain.h> 38 #include <linux/pm_runtime.h> 39 #include <linux/pm_wakeirq.h> 40 #include <linux/property.h> 41 #include <linux/rwsem.h> 42 #include <linux/slab.h> 43 44 #include "i2c-core.h" 45 46 #define CREATE_TRACE_POINTS 47 #include <trace/events/i2c.h> 48 49 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000 50 #define I2C_ADDR_OFFSET_SLAVE 0x1000 51 52 #define I2C_ADDR_7BITS_MAX 0x77 53 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1) 54 55 #define I2C_ADDR_DEVICE_ID 0x7c 56 57 /* 58 * core_lock protects i2c_adapter_idr, and guarantees that device detection, 59 * deletion of detected devices are serialized 60 */ 61 static DEFINE_MUTEX(core_lock); 62 static DEFINE_IDR(i2c_adapter_idr); 63 64 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); 65 66 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key); 67 static bool is_registered; 68 69 int i2c_transfer_trace_reg(void) 70 { 71 static_branch_inc(&i2c_trace_msg_key); 72 return 0; 73 } 74 75 void i2c_transfer_trace_unreg(void) 76 { 77 static_branch_dec(&i2c_trace_msg_key); 78 } 79 80 const char *i2c_freq_mode_string(u32 bus_freq_hz) 81 { 82 switch (bus_freq_hz) { 83 case I2C_MAX_STANDARD_MODE_FREQ: 84 return "Standard Mode (100 kHz)"; 85 case I2C_MAX_FAST_MODE_FREQ: 86 return "Fast Mode (400 kHz)"; 87 case I2C_MAX_FAST_MODE_PLUS_FREQ: 88 return "Fast Mode Plus (1.0 MHz)"; 89 case I2C_MAX_TURBO_MODE_FREQ: 90 return "Turbo Mode (1.4 MHz)"; 91 case I2C_MAX_HIGH_SPEED_MODE_FREQ: 92 return "High Speed Mode (3.4 MHz)"; 93 case I2C_MAX_ULTRA_FAST_MODE_FREQ: 94 return "Ultra Fast Mode (5.0 MHz)"; 95 default: 96 return "Unknown Mode"; 97 } 98 } 99 EXPORT_SYMBOL_GPL(i2c_freq_mode_string); 100 101 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, 102 const struct i2c_client *client) 103 { 104 if (!(id && client)) 105 return NULL; 106 107 while (id->name[0]) { 108 if (strcmp(client->name, id->name) == 0) 109 return id; 110 id++; 111 } 112 return NULL; 113 } 114 EXPORT_SYMBOL_GPL(i2c_match_id); 115 116 static int i2c_device_match(struct device *dev, struct device_driver *drv) 117 { 118 struct i2c_client *client = i2c_verify_client(dev); 119 struct i2c_driver *driver; 120 121 122 /* Attempt an OF style match */ 123 if (i2c_of_match_device(drv->of_match_table, client)) 124 return 1; 125 126 /* Then ACPI style match */ 127 if (acpi_driver_match_device(dev, drv)) 128 return 1; 129 130 driver = to_i2c_driver(drv); 131 132 /* Finally an I2C match */ 133 if (i2c_match_id(driver->id_table, client)) 134 return 1; 135 136 return 0; 137 } 138 139 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env) 140 { 141 struct i2c_client *client = to_i2c_client(dev); 142 int rc; 143 144 rc = of_device_uevent_modalias(dev, env); 145 if (rc != -ENODEV) 146 return rc; 147 148 rc = acpi_device_uevent_modalias(dev, env); 149 if (rc != -ENODEV) 150 return rc; 151 152 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name); 153 } 154 155 /* i2c bus recovery routines */ 156 static int get_scl_gpio_value(struct i2c_adapter *adap) 157 { 158 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod); 159 } 160 161 static void set_scl_gpio_value(struct i2c_adapter *adap, int val) 162 { 163 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val); 164 } 165 166 static int get_sda_gpio_value(struct i2c_adapter *adap) 167 { 168 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod); 169 } 170 171 static void set_sda_gpio_value(struct i2c_adapter *adap, int val) 172 { 173 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val); 174 } 175 176 static int i2c_generic_bus_free(struct i2c_adapter *adap) 177 { 178 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 179 int ret = -EOPNOTSUPP; 180 181 if (bri->get_bus_free) 182 ret = bri->get_bus_free(adap); 183 else if (bri->get_sda) 184 ret = bri->get_sda(adap); 185 186 if (ret < 0) 187 return ret; 188 189 return ret ? 0 : -EBUSY; 190 } 191 192 /* 193 * We are generating clock pulses. ndelay() determines durating of clk pulses. 194 * We will generate clock with rate 100 KHz and so duration of both clock levels 195 * is: delay in ns = (10^6 / 100) / 2 196 */ 197 #define RECOVERY_NDELAY 5000 198 #define RECOVERY_CLK_CNT 9 199 200 int i2c_generic_scl_recovery(struct i2c_adapter *adap) 201 { 202 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 203 int i = 0, scl = 1, ret = 0; 204 205 if (bri->prepare_recovery) 206 bri->prepare_recovery(adap); 207 if (bri->pinctrl) 208 pinctrl_select_state(bri->pinctrl, bri->pins_gpio); 209 210 /* 211 * If we can set SDA, we will always create a STOP to ensure additional 212 * pulses will do no harm. This is achieved by letting SDA follow SCL 213 * half a cycle later. Check the 'incomplete_write_byte' fault injector 214 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us 215 * here for simplicity. 216 */ 217 bri->set_scl(adap, scl); 218 ndelay(RECOVERY_NDELAY); 219 if (bri->set_sda) 220 bri->set_sda(adap, scl); 221 ndelay(RECOVERY_NDELAY / 2); 222 223 /* 224 * By this time SCL is high, as we need to give 9 falling-rising edges 225 */ 226 while (i++ < RECOVERY_CLK_CNT * 2) { 227 if (scl) { 228 /* SCL shouldn't be low here */ 229 if (!bri->get_scl(adap)) { 230 dev_err(&adap->dev, 231 "SCL is stuck low, exit recovery\n"); 232 ret = -EBUSY; 233 break; 234 } 235 } 236 237 scl = !scl; 238 bri->set_scl(adap, scl); 239 /* Creating STOP again, see above */ 240 if (scl) { 241 /* Honour minimum tsu:sto */ 242 ndelay(RECOVERY_NDELAY); 243 } else { 244 /* Honour minimum tf and thd:dat */ 245 ndelay(RECOVERY_NDELAY / 2); 246 } 247 if (bri->set_sda) 248 bri->set_sda(adap, scl); 249 ndelay(RECOVERY_NDELAY / 2); 250 251 if (scl) { 252 ret = i2c_generic_bus_free(adap); 253 if (ret == 0) 254 break; 255 } 256 } 257 258 /* If we can't check bus status, assume recovery worked */ 259 if (ret == -EOPNOTSUPP) 260 ret = 0; 261 262 if (bri->unprepare_recovery) 263 bri->unprepare_recovery(adap); 264 if (bri->pinctrl) 265 pinctrl_select_state(bri->pinctrl, bri->pins_default); 266 267 return ret; 268 } 269 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery); 270 271 int i2c_recover_bus(struct i2c_adapter *adap) 272 { 273 if (!adap->bus_recovery_info) 274 return -EBUSY; 275 276 dev_dbg(&adap->dev, "Trying i2c bus recovery\n"); 277 return adap->bus_recovery_info->recover_bus(adap); 278 } 279 EXPORT_SYMBOL_GPL(i2c_recover_bus); 280 281 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap) 282 { 283 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 284 struct device *dev = &adap->dev; 285 struct pinctrl *p = bri->pinctrl; 286 287 /* 288 * we can't change states without pinctrl, so remove the states if 289 * populated 290 */ 291 if (!p) { 292 bri->pins_default = NULL; 293 bri->pins_gpio = NULL; 294 return; 295 } 296 297 if (!bri->pins_default) { 298 bri->pins_default = pinctrl_lookup_state(p, 299 PINCTRL_STATE_DEFAULT); 300 if (IS_ERR(bri->pins_default)) { 301 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n"); 302 bri->pins_default = NULL; 303 } 304 } 305 if (!bri->pins_gpio) { 306 bri->pins_gpio = pinctrl_lookup_state(p, "gpio"); 307 if (IS_ERR(bri->pins_gpio)) 308 bri->pins_gpio = pinctrl_lookup_state(p, "recovery"); 309 310 if (IS_ERR(bri->pins_gpio)) { 311 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n"); 312 bri->pins_gpio = NULL; 313 } 314 } 315 316 /* for pinctrl state changes, we need all the information */ 317 if (bri->pins_default && bri->pins_gpio) { 318 dev_info(dev, "using pinctrl states for GPIO recovery"); 319 } else { 320 bri->pinctrl = NULL; 321 bri->pins_default = NULL; 322 bri->pins_gpio = NULL; 323 } 324 } 325 326 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap) 327 { 328 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 329 struct device *dev = &adap->dev; 330 struct gpio_desc *gpiod; 331 int ret = 0; 332 333 /* 334 * don't touch the recovery information if the driver is not using 335 * generic SCL recovery 336 */ 337 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery) 338 return 0; 339 340 /* 341 * pins might be taken as GPIO, so we should inform pinctrl about 342 * this and move the state to GPIO 343 */ 344 if (bri->pinctrl) 345 pinctrl_select_state(bri->pinctrl, bri->pins_gpio); 346 347 /* 348 * if there is incomplete or no recovery information, see if generic 349 * GPIO recovery is available 350 */ 351 if (!bri->scl_gpiod) { 352 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); 353 if (PTR_ERR(gpiod) == -EPROBE_DEFER) { 354 ret = -EPROBE_DEFER; 355 goto cleanup_pinctrl_state; 356 } 357 if (!IS_ERR(gpiod)) { 358 bri->scl_gpiod = gpiod; 359 bri->recover_bus = i2c_generic_scl_recovery; 360 dev_info(dev, "using generic GPIOs for recovery\n"); 361 } 362 } 363 364 /* SDA GPIOD line is optional, so we care about DEFER only */ 365 if (!bri->sda_gpiod) { 366 /* 367 * We have SCL. Pull SCL low and wait a bit so that SDA glitches 368 * have no effect. 369 */ 370 gpiod_direction_output(bri->scl_gpiod, 0); 371 udelay(10); 372 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN); 373 374 /* Wait a bit in case of a SDA glitch, and then release SCL. */ 375 udelay(10); 376 gpiod_direction_output(bri->scl_gpiod, 1); 377 378 if (PTR_ERR(gpiod) == -EPROBE_DEFER) { 379 ret = -EPROBE_DEFER; 380 goto cleanup_pinctrl_state; 381 } 382 if (!IS_ERR(gpiod)) 383 bri->sda_gpiod = gpiod; 384 } 385 386 cleanup_pinctrl_state: 387 /* change the state of the pins back to their default state */ 388 if (bri->pinctrl) 389 pinctrl_select_state(bri->pinctrl, bri->pins_default); 390 391 return ret; 392 } 393 394 static int i2c_gpio_init_recovery(struct i2c_adapter *adap) 395 { 396 i2c_gpio_init_pinctrl_recovery(adap); 397 return i2c_gpio_init_generic_recovery(adap); 398 } 399 400 static int i2c_init_recovery(struct i2c_adapter *adap) 401 { 402 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 403 bool is_error_level = true; 404 char *err_str; 405 406 if (!bri) 407 return 0; 408 409 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER) 410 return -EPROBE_DEFER; 411 412 if (!bri->recover_bus) { 413 err_str = "no suitable method provided"; 414 is_error_level = false; 415 goto err; 416 } 417 418 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) { 419 bri->get_scl = get_scl_gpio_value; 420 bri->set_scl = set_scl_gpio_value; 421 if (bri->sda_gpiod) { 422 bri->get_sda = get_sda_gpio_value; 423 /* FIXME: add proper flag instead of '0' once available */ 424 if (gpiod_get_direction(bri->sda_gpiod) == 0) 425 bri->set_sda = set_sda_gpio_value; 426 } 427 } else if (bri->recover_bus == i2c_generic_scl_recovery) { 428 /* Generic SCL recovery */ 429 if (!bri->set_scl || !bri->get_scl) { 430 err_str = "no {get|set}_scl() found"; 431 goto err; 432 } 433 if (!bri->set_sda && !bri->get_sda) { 434 err_str = "either get_sda() or set_sda() needed"; 435 goto err; 436 } 437 } 438 439 return 0; 440 err: 441 if (is_error_level) 442 dev_err(&adap->dev, "Not using recovery: %s\n", err_str); 443 else 444 dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str); 445 adap->bus_recovery_info = NULL; 446 447 return -EINVAL; 448 } 449 450 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client) 451 { 452 struct i2c_adapter *adap = client->adapter; 453 unsigned int irq; 454 455 if (!adap->host_notify_domain) 456 return -ENXIO; 457 458 if (client->flags & I2C_CLIENT_TEN) 459 return -EINVAL; 460 461 irq = irq_create_mapping(adap->host_notify_domain, client->addr); 462 463 return irq > 0 ? irq : -ENXIO; 464 } 465 466 static int i2c_device_probe(struct device *dev) 467 { 468 struct i2c_client *client = i2c_verify_client(dev); 469 struct i2c_adapter *adap; 470 struct i2c_driver *driver; 471 int status; 472 473 if (!client) 474 return 0; 475 476 adap = client->adapter; 477 client->irq = client->init_irq; 478 479 if (!client->irq) { 480 int irq = -ENOENT; 481 482 if (client->flags & I2C_CLIENT_HOST_NOTIFY) { 483 dev_dbg(dev, "Using Host Notify IRQ\n"); 484 /* Keep adapter active when Host Notify is required */ 485 pm_runtime_get_sync(&client->adapter->dev); 486 irq = i2c_smbus_host_notify_to_irq(client); 487 } else if (dev->of_node) { 488 irq = of_irq_get_byname(dev->of_node, "irq"); 489 if (irq == -EINVAL || irq == -ENODATA) 490 irq = of_irq_get(dev->of_node, 0); 491 } else if (ACPI_COMPANION(dev)) { 492 irq = i2c_acpi_get_irq(client); 493 } 494 if (irq == -EPROBE_DEFER) { 495 status = irq; 496 goto put_sync_adapter; 497 } 498 499 if (irq < 0) 500 irq = 0; 501 502 client->irq = irq; 503 } 504 505 driver = to_i2c_driver(dev->driver); 506 507 /* 508 * An I2C ID table is not mandatory, if and only if, a suitable OF 509 * or ACPI ID table is supplied for the probing device. 510 */ 511 if (!driver->id_table && 512 !acpi_driver_match_device(dev, dev->driver) && 513 !i2c_of_match_device(dev->driver->of_match_table, client)) { 514 status = -ENODEV; 515 goto put_sync_adapter; 516 } 517 518 if (client->flags & I2C_CLIENT_WAKE) { 519 int wakeirq; 520 521 wakeirq = of_irq_get_byname(dev->of_node, "wakeup"); 522 if (wakeirq == -EPROBE_DEFER) { 523 status = wakeirq; 524 goto put_sync_adapter; 525 } 526 527 device_init_wakeup(&client->dev, true); 528 529 if (wakeirq > 0 && wakeirq != client->irq) 530 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq); 531 else if (client->irq > 0) 532 status = dev_pm_set_wake_irq(dev, client->irq); 533 else 534 status = 0; 535 536 if (status) 537 dev_warn(&client->dev, "failed to set up wakeup irq\n"); 538 } 539 540 dev_dbg(dev, "probe\n"); 541 542 if (adap->bus_regulator) { 543 status = regulator_enable(adap->bus_regulator); 544 if (status < 0) { 545 dev_err(&adap->dev, "Failed to enable bus regulator\n"); 546 goto err_clear_wakeup_irq; 547 } 548 } 549 550 status = of_clk_set_defaults(dev->of_node, false); 551 if (status < 0) 552 goto err_clear_wakeup_irq; 553 554 status = dev_pm_domain_attach(&client->dev, true); 555 if (status) 556 goto err_clear_wakeup_irq; 557 558 client->devres_group_id = devres_open_group(&client->dev, NULL, 559 GFP_KERNEL); 560 if (!client->devres_group_id) { 561 status = -ENOMEM; 562 goto err_detach_pm_domain; 563 } 564 565 /* 566 * When there are no more users of probe(), 567 * rename probe_new to probe. 568 */ 569 if (driver->probe_new) 570 status = driver->probe_new(client); 571 else if (driver->probe) 572 status = driver->probe(client, 573 i2c_match_id(driver->id_table, client)); 574 else 575 status = -EINVAL; 576 577 /* 578 * Note that we are not closing the devres group opened above so 579 * even resources that were attached to the device after probe is 580 * run are released when i2c_device_remove() is executed. This is 581 * needed as some drivers would allocate additional resources, 582 * for example when updating firmware. 583 */ 584 585 if (status) 586 goto err_release_driver_resources; 587 588 return 0; 589 590 err_release_driver_resources: 591 devres_release_group(&client->dev, client->devres_group_id); 592 err_detach_pm_domain: 593 dev_pm_domain_detach(&client->dev, true); 594 err_clear_wakeup_irq: 595 dev_pm_clear_wake_irq(&client->dev); 596 device_init_wakeup(&client->dev, false); 597 put_sync_adapter: 598 if (client->flags & I2C_CLIENT_HOST_NOTIFY) 599 pm_runtime_put_sync(&client->adapter->dev); 600 601 return status; 602 } 603 604 static void i2c_device_remove(struct device *dev) 605 { 606 struct i2c_client *client = to_i2c_client(dev); 607 struct i2c_adapter *adap; 608 struct i2c_driver *driver; 609 610 adap = client->adapter; 611 driver = to_i2c_driver(dev->driver); 612 if (driver->remove) { 613 int status; 614 615 dev_dbg(dev, "remove\n"); 616 617 status = driver->remove(client); 618 if (status) 619 dev_warn(dev, "remove failed (%pe), will be ignored\n", ERR_PTR(status)); 620 } 621 622 devres_release_group(&client->dev, client->devres_group_id); 623 624 dev_pm_domain_detach(&client->dev, true); 625 if (!pm_runtime_status_suspended(&client->dev) && adap->bus_regulator) 626 regulator_disable(adap->bus_regulator); 627 628 dev_pm_clear_wake_irq(&client->dev); 629 device_init_wakeup(&client->dev, false); 630 631 client->irq = 0; 632 if (client->flags & I2C_CLIENT_HOST_NOTIFY) 633 pm_runtime_put(&client->adapter->dev); 634 } 635 636 #ifdef CONFIG_PM_SLEEP 637 static int i2c_resume_early(struct device *dev) 638 { 639 struct i2c_client *client = i2c_verify_client(dev); 640 int err; 641 642 if (!client) 643 return 0; 644 645 if (pm_runtime_status_suspended(&client->dev) && 646 client->adapter->bus_regulator) { 647 err = regulator_enable(client->adapter->bus_regulator); 648 if (err) 649 return err; 650 } 651 652 return pm_generic_resume_early(&client->dev); 653 } 654 655 static int i2c_suspend_late(struct device *dev) 656 { 657 struct i2c_client *client = i2c_verify_client(dev); 658 int err; 659 660 if (!client) 661 return 0; 662 663 err = pm_generic_suspend_late(&client->dev); 664 if (err) 665 return err; 666 667 if (!pm_runtime_status_suspended(&client->dev) && 668 client->adapter->bus_regulator) 669 return regulator_disable(client->adapter->bus_regulator); 670 671 return 0; 672 } 673 #endif 674 675 #ifdef CONFIG_PM 676 static int i2c_runtime_resume(struct device *dev) 677 { 678 struct i2c_client *client = i2c_verify_client(dev); 679 int err; 680 681 if (!client) 682 return 0; 683 684 if (client->adapter->bus_regulator) { 685 err = regulator_enable(client->adapter->bus_regulator); 686 if (err) 687 return err; 688 } 689 690 return pm_generic_runtime_resume(&client->dev); 691 } 692 693 static int i2c_runtime_suspend(struct device *dev) 694 { 695 struct i2c_client *client = i2c_verify_client(dev); 696 int err; 697 698 if (!client) 699 return 0; 700 701 err = pm_generic_runtime_suspend(&client->dev); 702 if (err) 703 return err; 704 705 if (client->adapter->bus_regulator) 706 return regulator_disable(client->adapter->bus_regulator); 707 return 0; 708 } 709 #endif 710 711 static const struct dev_pm_ops i2c_device_pm = { 712 SET_LATE_SYSTEM_SLEEP_PM_OPS(i2c_suspend_late, i2c_resume_early) 713 SET_RUNTIME_PM_OPS(i2c_runtime_suspend, i2c_runtime_resume, NULL) 714 }; 715 716 static void i2c_device_shutdown(struct device *dev) 717 { 718 struct i2c_client *client = i2c_verify_client(dev); 719 struct i2c_driver *driver; 720 721 if (!client || !dev->driver) 722 return; 723 driver = to_i2c_driver(dev->driver); 724 if (driver->shutdown) 725 driver->shutdown(client); 726 else if (client->irq > 0) 727 disable_irq(client->irq); 728 } 729 730 static void i2c_client_dev_release(struct device *dev) 731 { 732 kfree(to_i2c_client(dev)); 733 } 734 735 static ssize_t 736 name_show(struct device *dev, struct device_attribute *attr, char *buf) 737 { 738 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? 739 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); 740 } 741 static DEVICE_ATTR_RO(name); 742 743 static ssize_t 744 modalias_show(struct device *dev, struct device_attribute *attr, char *buf) 745 { 746 struct i2c_client *client = to_i2c_client(dev); 747 int len; 748 749 len = of_device_modalias(dev, buf, PAGE_SIZE); 750 if (len != -ENODEV) 751 return len; 752 753 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); 754 if (len != -ENODEV) 755 return len; 756 757 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); 758 } 759 static DEVICE_ATTR_RO(modalias); 760 761 static struct attribute *i2c_dev_attrs[] = { 762 &dev_attr_name.attr, 763 /* modalias helps coldplug: modprobe $(cat .../modalias) */ 764 &dev_attr_modalias.attr, 765 NULL 766 }; 767 ATTRIBUTE_GROUPS(i2c_dev); 768 769 struct bus_type i2c_bus_type = { 770 .name = "i2c", 771 .match = i2c_device_match, 772 .probe = i2c_device_probe, 773 .remove = i2c_device_remove, 774 .shutdown = i2c_device_shutdown, 775 .pm = &i2c_device_pm, 776 }; 777 EXPORT_SYMBOL_GPL(i2c_bus_type); 778 779 struct device_type i2c_client_type = { 780 .groups = i2c_dev_groups, 781 .uevent = i2c_device_uevent, 782 .release = i2c_client_dev_release, 783 }; 784 EXPORT_SYMBOL_GPL(i2c_client_type); 785 786 787 /** 788 * i2c_verify_client - return parameter as i2c_client, or NULL 789 * @dev: device, probably from some driver model iterator 790 * 791 * When traversing the driver model tree, perhaps using driver model 792 * iterators like @device_for_each_child(), you can't assume very much 793 * about the nodes you find. Use this function to avoid oopses caused 794 * by wrongly treating some non-I2C device as an i2c_client. 795 */ 796 struct i2c_client *i2c_verify_client(struct device *dev) 797 { 798 return (dev->type == &i2c_client_type) 799 ? to_i2c_client(dev) 800 : NULL; 801 } 802 EXPORT_SYMBOL(i2c_verify_client); 803 804 805 /* Return a unique address which takes the flags of the client into account */ 806 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client) 807 { 808 unsigned short addr = client->addr; 809 810 /* For some client flags, add an arbitrary offset to avoid collisions */ 811 if (client->flags & I2C_CLIENT_TEN) 812 addr |= I2C_ADDR_OFFSET_TEN_BIT; 813 814 if (client->flags & I2C_CLIENT_SLAVE) 815 addr |= I2C_ADDR_OFFSET_SLAVE; 816 817 return addr; 818 } 819 820 /* This is a permissive address validity check, I2C address map constraints 821 * are purposely not enforced, except for the general call address. */ 822 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags) 823 { 824 if (flags & I2C_CLIENT_TEN) { 825 /* 10-bit address, all values are valid */ 826 if (addr > 0x3ff) 827 return -EINVAL; 828 } else { 829 /* 7-bit address, reject the general call address */ 830 if (addr == 0x00 || addr > 0x7f) 831 return -EINVAL; 832 } 833 return 0; 834 } 835 836 /* And this is a strict address validity check, used when probing. If a 837 * device uses a reserved address, then it shouldn't be probed. 7-bit 838 * addressing is assumed, 10-bit address devices are rare and should be 839 * explicitly enumerated. */ 840 int i2c_check_7bit_addr_validity_strict(unsigned short addr) 841 { 842 /* 843 * Reserved addresses per I2C specification: 844 * 0x00 General call address / START byte 845 * 0x01 CBUS address 846 * 0x02 Reserved for different bus format 847 * 0x03 Reserved for future purposes 848 * 0x04-0x07 Hs-mode master code 849 * 0x78-0x7b 10-bit slave addressing 850 * 0x7c-0x7f Reserved for future purposes 851 */ 852 if (addr < 0x08 || addr > 0x77) 853 return -EINVAL; 854 return 0; 855 } 856 857 static int __i2c_check_addr_busy(struct device *dev, void *addrp) 858 { 859 struct i2c_client *client = i2c_verify_client(dev); 860 int addr = *(int *)addrp; 861 862 if (client && i2c_encode_flags_to_addr(client) == addr) 863 return -EBUSY; 864 return 0; 865 } 866 867 /* walk up mux tree */ 868 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) 869 { 870 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 871 int result; 872 873 result = device_for_each_child(&adapter->dev, &addr, 874 __i2c_check_addr_busy); 875 876 if (!result && parent) 877 result = i2c_check_mux_parents(parent, addr); 878 879 return result; 880 } 881 882 /* recurse down mux tree */ 883 static int i2c_check_mux_children(struct device *dev, void *addrp) 884 { 885 int result; 886 887 if (dev->type == &i2c_adapter_type) 888 result = device_for_each_child(dev, addrp, 889 i2c_check_mux_children); 890 else 891 result = __i2c_check_addr_busy(dev, addrp); 892 893 return result; 894 } 895 896 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) 897 { 898 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 899 int result = 0; 900 901 if (parent) 902 result = i2c_check_mux_parents(parent, addr); 903 904 if (!result) 905 result = device_for_each_child(&adapter->dev, &addr, 906 i2c_check_mux_children); 907 908 return result; 909 } 910 911 /** 912 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment 913 * @adapter: Target I2C bus segment 914 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT 915 * locks only this branch in the adapter tree 916 */ 917 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, 918 unsigned int flags) 919 { 920 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); 921 } 922 923 /** 924 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment 925 * @adapter: Target I2C bus segment 926 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT 927 * trylocks only this branch in the adapter tree 928 */ 929 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, 930 unsigned int flags) 931 { 932 return rt_mutex_trylock(&adapter->bus_lock); 933 } 934 935 /** 936 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment 937 * @adapter: Target I2C bus segment 938 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT 939 * unlocks only this branch in the adapter tree 940 */ 941 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, 942 unsigned int flags) 943 { 944 rt_mutex_unlock(&adapter->bus_lock); 945 } 946 947 static void i2c_dev_set_name(struct i2c_adapter *adap, 948 struct i2c_client *client, 949 struct i2c_board_info const *info) 950 { 951 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 952 953 if (info && info->dev_name) { 954 dev_set_name(&client->dev, "i2c-%s", info->dev_name); 955 return; 956 } 957 958 if (adev) { 959 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev)); 960 return; 961 } 962 963 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), 964 i2c_encode_flags_to_addr(client)); 965 } 966 967 int i2c_dev_irq_from_resources(const struct resource *resources, 968 unsigned int num_resources) 969 { 970 struct irq_data *irqd; 971 int i; 972 973 for (i = 0; i < num_resources; i++) { 974 const struct resource *r = &resources[i]; 975 976 if (resource_type(r) != IORESOURCE_IRQ) 977 continue; 978 979 if (r->flags & IORESOURCE_BITS) { 980 irqd = irq_get_irq_data(r->start); 981 if (!irqd) 982 break; 983 984 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); 985 } 986 987 return r->start; 988 } 989 990 return 0; 991 } 992 993 /** 994 * i2c_new_client_device - instantiate an i2c device 995 * @adap: the adapter managing the device 996 * @info: describes one I2C device; bus_num is ignored 997 * Context: can sleep 998 * 999 * Create an i2c device. Binding is handled through driver model 1000 * probe()/remove() methods. A driver may be bound to this device when we 1001 * return from this function, or any later moment (e.g. maybe hotplugging will 1002 * load the driver module). This call is not appropriate for use by mainboard 1003 * initialization logic, which usually runs during an arch_initcall() long 1004 * before any i2c_adapter could exist. 1005 * 1006 * This returns the new i2c client, which may be saved for later use with 1007 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1008 */ 1009 struct i2c_client * 1010 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info) 1011 { 1012 struct i2c_client *client; 1013 int status; 1014 1015 client = kzalloc(sizeof *client, GFP_KERNEL); 1016 if (!client) 1017 return ERR_PTR(-ENOMEM); 1018 1019 client->adapter = adap; 1020 1021 client->dev.platform_data = info->platform_data; 1022 client->flags = info->flags; 1023 client->addr = info->addr; 1024 1025 client->init_irq = info->irq; 1026 if (!client->init_irq) 1027 client->init_irq = i2c_dev_irq_from_resources(info->resources, 1028 info->num_resources); 1029 1030 strlcpy(client->name, info->type, sizeof(client->name)); 1031 1032 status = i2c_check_addr_validity(client->addr, client->flags); 1033 if (status) { 1034 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", 1035 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); 1036 goto out_err_silent; 1037 } 1038 1039 /* Check for address business */ 1040 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); 1041 if (status) 1042 goto out_err; 1043 1044 client->dev.parent = &client->adapter->dev; 1045 client->dev.bus = &i2c_bus_type; 1046 client->dev.type = &i2c_client_type; 1047 client->dev.of_node = of_node_get(info->of_node); 1048 client->dev.fwnode = info->fwnode; 1049 1050 i2c_dev_set_name(adap, client, info); 1051 1052 if (info->swnode) { 1053 status = device_add_software_node(&client->dev, info->swnode); 1054 if (status) { 1055 dev_err(&adap->dev, 1056 "Failed to add software node to client %s: %d\n", 1057 client->name, status); 1058 goto out_err_put_of_node; 1059 } 1060 } 1061 1062 status = device_register(&client->dev); 1063 if (status) 1064 goto out_remove_swnode; 1065 1066 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", 1067 client->name, dev_name(&client->dev)); 1068 1069 return client; 1070 1071 out_remove_swnode: 1072 device_remove_software_node(&client->dev); 1073 out_err_put_of_node: 1074 of_node_put(info->of_node); 1075 out_err: 1076 dev_err(&adap->dev, 1077 "Failed to register i2c client %s at 0x%02x (%d)\n", 1078 client->name, client->addr, status); 1079 out_err_silent: 1080 kfree(client); 1081 return ERR_PTR(status); 1082 } 1083 EXPORT_SYMBOL_GPL(i2c_new_client_device); 1084 1085 /** 1086 * i2c_unregister_device - reverse effect of i2c_new_*_device() 1087 * @client: value returned from i2c_new_*_device() 1088 * Context: can sleep 1089 */ 1090 void i2c_unregister_device(struct i2c_client *client) 1091 { 1092 if (IS_ERR_OR_NULL(client)) 1093 return; 1094 1095 if (client->dev.of_node) { 1096 of_node_clear_flag(client->dev.of_node, OF_POPULATED); 1097 of_node_put(client->dev.of_node); 1098 } 1099 1100 if (ACPI_COMPANION(&client->dev)) 1101 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev)); 1102 device_remove_software_node(&client->dev); 1103 device_unregister(&client->dev); 1104 } 1105 EXPORT_SYMBOL_GPL(i2c_unregister_device); 1106 1107 1108 static const struct i2c_device_id dummy_id[] = { 1109 { "dummy", 0 }, 1110 { }, 1111 }; 1112 1113 static int dummy_probe(struct i2c_client *client, 1114 const struct i2c_device_id *id) 1115 { 1116 return 0; 1117 } 1118 1119 static int dummy_remove(struct i2c_client *client) 1120 { 1121 return 0; 1122 } 1123 1124 static struct i2c_driver dummy_driver = { 1125 .driver.name = "dummy", 1126 .probe = dummy_probe, 1127 .remove = dummy_remove, 1128 .id_table = dummy_id, 1129 }; 1130 1131 /** 1132 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1133 * @adapter: the adapter managing the device 1134 * @address: seven bit address to be used 1135 * Context: can sleep 1136 * 1137 * This returns an I2C client bound to the "dummy" driver, intended for use 1138 * with devices that consume multiple addresses. Examples of such chips 1139 * include various EEPROMS (like 24c04 and 24c08 models). 1140 * 1141 * These dummy devices have two main uses. First, most I2C and SMBus calls 1142 * except i2c_transfer() need a client handle; the dummy will be that handle. 1143 * And second, this prevents the specified address from being bound to a 1144 * different driver. 1145 * 1146 * This returns the new i2c client, which should be saved for later use with 1147 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1148 */ 1149 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address) 1150 { 1151 struct i2c_board_info info = { 1152 I2C_BOARD_INFO("dummy", address), 1153 }; 1154 1155 return i2c_new_client_device(adapter, &info); 1156 } 1157 EXPORT_SYMBOL_GPL(i2c_new_dummy_device); 1158 1159 static void devm_i2c_release_dummy(void *client) 1160 { 1161 i2c_unregister_device(client); 1162 } 1163 1164 /** 1165 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1166 * @dev: device the managed resource is bound to 1167 * @adapter: the adapter managing the device 1168 * @address: seven bit address to be used 1169 * Context: can sleep 1170 * 1171 * This is the device-managed version of @i2c_new_dummy_device. It returns the 1172 * new i2c client or an ERR_PTR in case of an error. 1173 */ 1174 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev, 1175 struct i2c_adapter *adapter, 1176 u16 address) 1177 { 1178 struct i2c_client *client; 1179 int ret; 1180 1181 client = i2c_new_dummy_device(adapter, address); 1182 if (IS_ERR(client)) 1183 return client; 1184 1185 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client); 1186 if (ret) 1187 return ERR_PTR(ret); 1188 1189 return client; 1190 } 1191 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device); 1192 1193 /** 1194 * i2c_new_ancillary_device - Helper to get the instantiated secondary address 1195 * and create the associated device 1196 * @client: Handle to the primary client 1197 * @name: Handle to specify which secondary address to get 1198 * @default_addr: Used as a fallback if no secondary address was specified 1199 * Context: can sleep 1200 * 1201 * I2C clients can be composed of multiple I2C slaves bound together in a single 1202 * component. The I2C client driver then binds to the master I2C slave and needs 1203 * to create I2C dummy clients to communicate with all the other slaves. 1204 * 1205 * This function creates and returns an I2C dummy client whose I2C address is 1206 * retrieved from the platform firmware based on the given slave name. If no 1207 * address is specified by the firmware default_addr is used. 1208 * 1209 * On DT-based platforms the address is retrieved from the "reg" property entry 1210 * cell whose "reg-names" value matches the slave name. 1211 * 1212 * This returns the new i2c client, which should be saved for later use with 1213 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1214 */ 1215 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, 1216 const char *name, 1217 u16 default_addr) 1218 { 1219 struct device_node *np = client->dev.of_node; 1220 u32 addr = default_addr; 1221 int i; 1222 1223 if (np) { 1224 i = of_property_match_string(np, "reg-names", name); 1225 if (i >= 0) 1226 of_property_read_u32_index(np, "reg", i, &addr); 1227 } 1228 1229 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); 1230 return i2c_new_dummy_device(client->adapter, addr); 1231 } 1232 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device); 1233 1234 /* ------------------------------------------------------------------------- */ 1235 1236 /* I2C bus adapters -- one roots each I2C or SMBUS segment */ 1237 1238 static void i2c_adapter_dev_release(struct device *dev) 1239 { 1240 struct i2c_adapter *adap = to_i2c_adapter(dev); 1241 complete(&adap->dev_released); 1242 } 1243 1244 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) 1245 { 1246 unsigned int depth = 0; 1247 1248 while ((adapter = i2c_parent_is_i2c_adapter(adapter))) 1249 depth++; 1250 1251 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES, 1252 "adapter depth exceeds lockdep subclass limit\n"); 1253 1254 return depth; 1255 } 1256 EXPORT_SYMBOL_GPL(i2c_adapter_depth); 1257 1258 /* 1259 * Let users instantiate I2C devices through sysfs. This can be used when 1260 * platform initialization code doesn't contain the proper data for 1261 * whatever reason. Also useful for drivers that do device detection and 1262 * detection fails, either because the device uses an unexpected address, 1263 * or this is a compatible device with different ID register values. 1264 * 1265 * Parameter checking may look overzealous, but we really don't want 1266 * the user to provide incorrect parameters. 1267 */ 1268 static ssize_t 1269 new_device_store(struct device *dev, struct device_attribute *attr, 1270 const char *buf, size_t count) 1271 { 1272 struct i2c_adapter *adap = to_i2c_adapter(dev); 1273 struct i2c_board_info info; 1274 struct i2c_client *client; 1275 char *blank, end; 1276 int res; 1277 1278 memset(&info, 0, sizeof(struct i2c_board_info)); 1279 1280 blank = strchr(buf, ' '); 1281 if (!blank) { 1282 dev_err(dev, "%s: Missing parameters\n", "new_device"); 1283 return -EINVAL; 1284 } 1285 if (blank - buf > I2C_NAME_SIZE - 1) { 1286 dev_err(dev, "%s: Invalid device name\n", "new_device"); 1287 return -EINVAL; 1288 } 1289 memcpy(info.type, buf, blank - buf); 1290 1291 /* Parse remaining parameters, reject extra parameters */ 1292 res = sscanf(++blank, "%hi%c", &info.addr, &end); 1293 if (res < 1) { 1294 dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); 1295 return -EINVAL; 1296 } 1297 if (res > 1 && end != '\n') { 1298 dev_err(dev, "%s: Extra parameters\n", "new_device"); 1299 return -EINVAL; 1300 } 1301 1302 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) { 1303 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT; 1304 info.flags |= I2C_CLIENT_TEN; 1305 } 1306 1307 if (info.addr & I2C_ADDR_OFFSET_SLAVE) { 1308 info.addr &= ~I2C_ADDR_OFFSET_SLAVE; 1309 info.flags |= I2C_CLIENT_SLAVE; 1310 } 1311 1312 client = i2c_new_client_device(adap, &info); 1313 if (IS_ERR(client)) 1314 return PTR_ERR(client); 1315 1316 /* Keep track of the added device */ 1317 mutex_lock(&adap->userspace_clients_lock); 1318 list_add_tail(&client->detected, &adap->userspace_clients); 1319 mutex_unlock(&adap->userspace_clients_lock); 1320 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", 1321 info.type, info.addr); 1322 1323 return count; 1324 } 1325 static DEVICE_ATTR_WO(new_device); 1326 1327 /* 1328 * And of course let the users delete the devices they instantiated, if 1329 * they got it wrong. This interface can only be used to delete devices 1330 * instantiated by i2c_sysfs_new_device above. This guarantees that we 1331 * don't delete devices to which some kernel code still has references. 1332 * 1333 * Parameter checking may look overzealous, but we really don't want 1334 * the user to delete the wrong device. 1335 */ 1336 static ssize_t 1337 delete_device_store(struct device *dev, struct device_attribute *attr, 1338 const char *buf, size_t count) 1339 { 1340 struct i2c_adapter *adap = to_i2c_adapter(dev); 1341 struct i2c_client *client, *next; 1342 unsigned short addr; 1343 char end; 1344 int res; 1345 1346 /* Parse parameters, reject extra parameters */ 1347 res = sscanf(buf, "%hi%c", &addr, &end); 1348 if (res < 1) { 1349 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); 1350 return -EINVAL; 1351 } 1352 if (res > 1 && end != '\n') { 1353 dev_err(dev, "%s: Extra parameters\n", "delete_device"); 1354 return -EINVAL; 1355 } 1356 1357 /* Make sure the device was added through sysfs */ 1358 res = -ENOENT; 1359 mutex_lock_nested(&adap->userspace_clients_lock, 1360 i2c_adapter_depth(adap)); 1361 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1362 detected) { 1363 if (i2c_encode_flags_to_addr(client) == addr) { 1364 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", 1365 "delete_device", client->name, client->addr); 1366 1367 list_del(&client->detected); 1368 i2c_unregister_device(client); 1369 res = count; 1370 break; 1371 } 1372 } 1373 mutex_unlock(&adap->userspace_clients_lock); 1374 1375 if (res < 0) 1376 dev_err(dev, "%s: Can't find device in list\n", 1377 "delete_device"); 1378 return res; 1379 } 1380 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL, 1381 delete_device_store); 1382 1383 static struct attribute *i2c_adapter_attrs[] = { 1384 &dev_attr_name.attr, 1385 &dev_attr_new_device.attr, 1386 &dev_attr_delete_device.attr, 1387 NULL 1388 }; 1389 ATTRIBUTE_GROUPS(i2c_adapter); 1390 1391 struct device_type i2c_adapter_type = { 1392 .groups = i2c_adapter_groups, 1393 .release = i2c_adapter_dev_release, 1394 }; 1395 EXPORT_SYMBOL_GPL(i2c_adapter_type); 1396 1397 /** 1398 * i2c_verify_adapter - return parameter as i2c_adapter or NULL 1399 * @dev: device, probably from some driver model iterator 1400 * 1401 * When traversing the driver model tree, perhaps using driver model 1402 * iterators like @device_for_each_child(), you can't assume very much 1403 * about the nodes you find. Use this function to avoid oopses caused 1404 * by wrongly treating some non-I2C device as an i2c_adapter. 1405 */ 1406 struct i2c_adapter *i2c_verify_adapter(struct device *dev) 1407 { 1408 return (dev->type == &i2c_adapter_type) 1409 ? to_i2c_adapter(dev) 1410 : NULL; 1411 } 1412 EXPORT_SYMBOL(i2c_verify_adapter); 1413 1414 #ifdef CONFIG_I2C_COMPAT 1415 static struct class_compat *i2c_adapter_compat_class; 1416 #endif 1417 1418 static void i2c_scan_static_board_info(struct i2c_adapter *adapter) 1419 { 1420 struct i2c_devinfo *devinfo; 1421 1422 down_read(&__i2c_board_lock); 1423 list_for_each_entry(devinfo, &__i2c_board_list, list) { 1424 if (devinfo->busnum == adapter->nr && 1425 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info))) 1426 dev_err(&adapter->dev, 1427 "Can't create device at 0x%02x\n", 1428 devinfo->board_info.addr); 1429 } 1430 up_read(&__i2c_board_lock); 1431 } 1432 1433 static int i2c_do_add_adapter(struct i2c_driver *driver, 1434 struct i2c_adapter *adap) 1435 { 1436 /* Detect supported devices on that bus, and instantiate them */ 1437 i2c_detect(adap, driver); 1438 1439 return 0; 1440 } 1441 1442 static int __process_new_adapter(struct device_driver *d, void *data) 1443 { 1444 return i2c_do_add_adapter(to_i2c_driver(d), data); 1445 } 1446 1447 static const struct i2c_lock_operations i2c_adapter_lock_ops = { 1448 .lock_bus = i2c_adapter_lock_bus, 1449 .trylock_bus = i2c_adapter_trylock_bus, 1450 .unlock_bus = i2c_adapter_unlock_bus, 1451 }; 1452 1453 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap) 1454 { 1455 struct irq_domain *domain = adap->host_notify_domain; 1456 irq_hw_number_t hwirq; 1457 1458 if (!domain) 1459 return; 1460 1461 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++) 1462 irq_dispose_mapping(irq_find_mapping(domain, hwirq)); 1463 1464 irq_domain_remove(domain); 1465 adap->host_notify_domain = NULL; 1466 } 1467 1468 static int i2c_host_notify_irq_map(struct irq_domain *h, 1469 unsigned int virq, 1470 irq_hw_number_t hw_irq_num) 1471 { 1472 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq); 1473 1474 return 0; 1475 } 1476 1477 static const struct irq_domain_ops i2c_host_notify_irq_ops = { 1478 .map = i2c_host_notify_irq_map, 1479 }; 1480 1481 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap) 1482 { 1483 struct irq_domain *domain; 1484 1485 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY)) 1486 return 0; 1487 1488 domain = irq_domain_create_linear(adap->dev.parent->fwnode, 1489 I2C_ADDR_7BITS_COUNT, 1490 &i2c_host_notify_irq_ops, adap); 1491 if (!domain) 1492 return -ENOMEM; 1493 1494 adap->host_notify_domain = domain; 1495 1496 return 0; 1497 } 1498 1499 /** 1500 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct 1501 * I2C client. 1502 * @adap: the adapter 1503 * @addr: the I2C address of the notifying device 1504 * Context: can't sleep 1505 * 1506 * Helper function to be called from an I2C bus driver's interrupt 1507 * handler. It will schedule the Host Notify IRQ. 1508 */ 1509 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr) 1510 { 1511 int irq; 1512 1513 if (!adap) 1514 return -EINVAL; 1515 1516 irq = irq_find_mapping(adap->host_notify_domain, addr); 1517 if (irq <= 0) 1518 return -ENXIO; 1519 1520 generic_handle_irq(irq); 1521 1522 return 0; 1523 } 1524 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify); 1525 1526 static int i2c_register_adapter(struct i2c_adapter *adap) 1527 { 1528 int res = -EINVAL; 1529 1530 /* Can't register until after driver model init */ 1531 if (WARN_ON(!is_registered)) { 1532 res = -EAGAIN; 1533 goto out_list; 1534 } 1535 1536 /* Sanity checks */ 1537 if (WARN(!adap->name[0], "i2c adapter has no name")) 1538 goto out_list; 1539 1540 if (!adap->algo) { 1541 pr_err("adapter '%s': no algo supplied!\n", adap->name); 1542 goto out_list; 1543 } 1544 1545 if (!adap->lock_ops) 1546 adap->lock_ops = &i2c_adapter_lock_ops; 1547 1548 adap->locked_flags = 0; 1549 rt_mutex_init(&adap->bus_lock); 1550 rt_mutex_init(&adap->mux_lock); 1551 mutex_init(&adap->userspace_clients_lock); 1552 INIT_LIST_HEAD(&adap->userspace_clients); 1553 1554 /* Set default timeout to 1 second if not already set */ 1555 if (adap->timeout == 0) 1556 adap->timeout = HZ; 1557 1558 /* register soft irqs for Host Notify */ 1559 res = i2c_setup_host_notify_irq_domain(adap); 1560 if (res) { 1561 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n", 1562 adap->name, res); 1563 goto out_list; 1564 } 1565 1566 dev_set_name(&adap->dev, "i2c-%d", adap->nr); 1567 adap->dev.bus = &i2c_bus_type; 1568 adap->dev.type = &i2c_adapter_type; 1569 res = device_register(&adap->dev); 1570 if (res) { 1571 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); 1572 goto out_list; 1573 } 1574 1575 res = of_i2c_setup_smbus_alert(adap); 1576 if (res) 1577 goto out_reg; 1578 1579 pm_runtime_no_callbacks(&adap->dev); 1580 pm_suspend_ignore_children(&adap->dev, true); 1581 pm_runtime_enable(&adap->dev); 1582 1583 res = i2c_init_recovery(adap); 1584 if (res == -EPROBE_DEFER) 1585 goto out_reg; 1586 1587 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); 1588 1589 #ifdef CONFIG_I2C_COMPAT 1590 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, 1591 adap->dev.parent); 1592 if (res) 1593 dev_warn(&adap->dev, 1594 "Failed to create compatibility class link\n"); 1595 #endif 1596 1597 /* create pre-declared device nodes */ 1598 of_i2c_register_devices(adap); 1599 i2c_acpi_install_space_handler(adap); 1600 i2c_acpi_register_devices(adap); 1601 1602 if (adap->nr < __i2c_first_dynamic_bus_num) 1603 i2c_scan_static_board_info(adap); 1604 1605 /* Notify drivers */ 1606 mutex_lock(&core_lock); 1607 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); 1608 mutex_unlock(&core_lock); 1609 1610 return 0; 1611 1612 out_reg: 1613 init_completion(&adap->dev_released); 1614 device_unregister(&adap->dev); 1615 wait_for_completion(&adap->dev_released); 1616 out_list: 1617 mutex_lock(&core_lock); 1618 idr_remove(&i2c_adapter_idr, adap->nr); 1619 mutex_unlock(&core_lock); 1620 return res; 1621 } 1622 1623 /** 1624 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 1625 * @adap: the adapter to register (with adap->nr initialized) 1626 * Context: can sleep 1627 * 1628 * See i2c_add_numbered_adapter() for details. 1629 */ 1630 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) 1631 { 1632 int id; 1633 1634 mutex_lock(&core_lock); 1635 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); 1636 mutex_unlock(&core_lock); 1637 if (WARN(id < 0, "couldn't get idr")) 1638 return id == -ENOSPC ? -EBUSY : id; 1639 1640 return i2c_register_adapter(adap); 1641 } 1642 1643 /** 1644 * i2c_add_adapter - declare i2c adapter, use dynamic bus number 1645 * @adapter: the adapter to add 1646 * Context: can sleep 1647 * 1648 * This routine is used to declare an I2C adapter when its bus number 1649 * doesn't matter or when its bus number is specified by an dt alias. 1650 * Examples of bases when the bus number doesn't matter: I2C adapters 1651 * dynamically added by USB links or PCI plugin cards. 1652 * 1653 * When this returns zero, a new bus number was allocated and stored 1654 * in adap->nr, and the specified adapter became available for clients. 1655 * Otherwise, a negative errno value is returned. 1656 */ 1657 int i2c_add_adapter(struct i2c_adapter *adapter) 1658 { 1659 struct device *dev = &adapter->dev; 1660 int id; 1661 1662 if (dev->of_node) { 1663 id = of_alias_get_id(dev->of_node, "i2c"); 1664 if (id >= 0) { 1665 adapter->nr = id; 1666 return __i2c_add_numbered_adapter(adapter); 1667 } 1668 } 1669 1670 mutex_lock(&core_lock); 1671 id = idr_alloc(&i2c_adapter_idr, adapter, 1672 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); 1673 mutex_unlock(&core_lock); 1674 if (WARN(id < 0, "couldn't get idr")) 1675 return id; 1676 1677 adapter->nr = id; 1678 1679 return i2c_register_adapter(adapter); 1680 } 1681 EXPORT_SYMBOL(i2c_add_adapter); 1682 1683 /** 1684 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number 1685 * @adap: the adapter to register (with adap->nr initialized) 1686 * Context: can sleep 1687 * 1688 * This routine is used to declare an I2C adapter when its bus number 1689 * matters. For example, use it for I2C adapters from system-on-chip CPUs, 1690 * or otherwise built in to the system's mainboard, and where i2c_board_info 1691 * is used to properly configure I2C devices. 1692 * 1693 * If the requested bus number is set to -1, then this function will behave 1694 * identically to i2c_add_adapter, and will dynamically assign a bus number. 1695 * 1696 * If no devices have pre-been declared for this bus, then be sure to 1697 * register the adapter before any dynamically allocated ones. Otherwise 1698 * the required bus ID may not be available. 1699 * 1700 * When this returns zero, the specified adapter became available for 1701 * clients using the bus number provided in adap->nr. Also, the table 1702 * of I2C devices pre-declared using i2c_register_board_info() is scanned, 1703 * and the appropriate driver model device nodes are created. Otherwise, a 1704 * negative errno value is returned. 1705 */ 1706 int i2c_add_numbered_adapter(struct i2c_adapter *adap) 1707 { 1708 if (adap->nr == -1) /* -1 means dynamically assign bus id */ 1709 return i2c_add_adapter(adap); 1710 1711 return __i2c_add_numbered_adapter(adap); 1712 } 1713 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); 1714 1715 static void i2c_do_del_adapter(struct i2c_driver *driver, 1716 struct i2c_adapter *adapter) 1717 { 1718 struct i2c_client *client, *_n; 1719 1720 /* Remove the devices we created ourselves as the result of hardware 1721 * probing (using a driver's detect method) */ 1722 list_for_each_entry_safe(client, _n, &driver->clients, detected) { 1723 if (client->adapter == adapter) { 1724 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", 1725 client->name, client->addr); 1726 list_del(&client->detected); 1727 i2c_unregister_device(client); 1728 } 1729 } 1730 } 1731 1732 static int __unregister_client(struct device *dev, void *dummy) 1733 { 1734 struct i2c_client *client = i2c_verify_client(dev); 1735 if (client && strcmp(client->name, "dummy")) 1736 i2c_unregister_device(client); 1737 return 0; 1738 } 1739 1740 static int __unregister_dummy(struct device *dev, void *dummy) 1741 { 1742 struct i2c_client *client = i2c_verify_client(dev); 1743 i2c_unregister_device(client); 1744 return 0; 1745 } 1746 1747 static int __process_removed_adapter(struct device_driver *d, void *data) 1748 { 1749 i2c_do_del_adapter(to_i2c_driver(d), data); 1750 return 0; 1751 } 1752 1753 /** 1754 * i2c_del_adapter - unregister I2C adapter 1755 * @adap: the adapter being unregistered 1756 * Context: can sleep 1757 * 1758 * This unregisters an I2C adapter which was previously registered 1759 * by @i2c_add_adapter or @i2c_add_numbered_adapter. 1760 */ 1761 void i2c_del_adapter(struct i2c_adapter *adap) 1762 { 1763 struct i2c_adapter *found; 1764 struct i2c_client *client, *next; 1765 1766 /* First make sure that this adapter was ever added */ 1767 mutex_lock(&core_lock); 1768 found = idr_find(&i2c_adapter_idr, adap->nr); 1769 mutex_unlock(&core_lock); 1770 if (found != adap) { 1771 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); 1772 return; 1773 } 1774 1775 i2c_acpi_remove_space_handler(adap); 1776 /* Tell drivers about this removal */ 1777 mutex_lock(&core_lock); 1778 bus_for_each_drv(&i2c_bus_type, NULL, adap, 1779 __process_removed_adapter); 1780 mutex_unlock(&core_lock); 1781 1782 /* Remove devices instantiated from sysfs */ 1783 mutex_lock_nested(&adap->userspace_clients_lock, 1784 i2c_adapter_depth(adap)); 1785 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1786 detected) { 1787 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, 1788 client->addr); 1789 list_del(&client->detected); 1790 i2c_unregister_device(client); 1791 } 1792 mutex_unlock(&adap->userspace_clients_lock); 1793 1794 /* Detach any active clients. This can't fail, thus we do not 1795 * check the returned value. This is a two-pass process, because 1796 * we can't remove the dummy devices during the first pass: they 1797 * could have been instantiated by real devices wishing to clean 1798 * them up properly, so we give them a chance to do that first. */ 1799 device_for_each_child(&adap->dev, NULL, __unregister_client); 1800 device_for_each_child(&adap->dev, NULL, __unregister_dummy); 1801 1802 #ifdef CONFIG_I2C_COMPAT 1803 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, 1804 adap->dev.parent); 1805 #endif 1806 1807 /* device name is gone after device_unregister */ 1808 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); 1809 1810 pm_runtime_disable(&adap->dev); 1811 1812 i2c_host_notify_irq_teardown(adap); 1813 1814 /* wait until all references to the device are gone 1815 * 1816 * FIXME: This is old code and should ideally be replaced by an 1817 * alternative which results in decoupling the lifetime of the struct 1818 * device from the i2c_adapter, like spi or netdev do. Any solution 1819 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled! 1820 */ 1821 init_completion(&adap->dev_released); 1822 device_unregister(&adap->dev); 1823 wait_for_completion(&adap->dev_released); 1824 1825 /* free bus id */ 1826 mutex_lock(&core_lock); 1827 idr_remove(&i2c_adapter_idr, adap->nr); 1828 mutex_unlock(&core_lock); 1829 1830 /* Clear the device structure in case this adapter is ever going to be 1831 added again */ 1832 memset(&adap->dev, 0, sizeof(adap->dev)); 1833 } 1834 EXPORT_SYMBOL(i2c_del_adapter); 1835 1836 static void devm_i2c_del_adapter(void *adapter) 1837 { 1838 i2c_del_adapter(adapter); 1839 } 1840 1841 /** 1842 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter() 1843 * @dev: managing device for adding this I2C adapter 1844 * @adapter: the adapter to add 1845 * Context: can sleep 1846 * 1847 * Add adapter with dynamic bus number, same with i2c_add_adapter() 1848 * but the adapter will be auto deleted on driver detach. 1849 */ 1850 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter) 1851 { 1852 int ret; 1853 1854 ret = i2c_add_adapter(adapter); 1855 if (ret) 1856 return ret; 1857 1858 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter); 1859 } 1860 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter); 1861 1862 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p, 1863 u32 def_val, bool use_def) 1864 { 1865 int ret; 1866 1867 ret = device_property_read_u32(dev, prop_name, cur_val_p); 1868 if (ret && use_def) 1869 *cur_val_p = def_val; 1870 1871 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p); 1872 } 1873 1874 /** 1875 * i2c_parse_fw_timings - get I2C related timing parameters from firmware 1876 * @dev: The device to scan for I2C timing properties 1877 * @t: the i2c_timings struct to be filled with values 1878 * @use_defaults: bool to use sane defaults derived from the I2C specification 1879 * when properties are not found, otherwise don't update 1880 * 1881 * Scan the device for the generic I2C properties describing timing parameters 1882 * for the signal and fill the given struct with the results. If a property was 1883 * not found and use_defaults was true, then maximum timings are assumed which 1884 * are derived from the I2C specification. If use_defaults is not used, the 1885 * results will be as before, so drivers can apply their own defaults before 1886 * calling this helper. The latter is mainly intended for avoiding regressions 1887 * of existing drivers which want to switch to this function. New drivers 1888 * almost always should use the defaults. 1889 */ 1890 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) 1891 { 1892 bool u = use_defaults; 1893 u32 d; 1894 1895 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz, 1896 I2C_MAX_STANDARD_MODE_FREQ, u); 1897 1898 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 : 1899 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1900 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u); 1901 1902 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1903 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u); 1904 1905 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns", 1906 &t->scl_int_delay_ns, 0, u); 1907 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns, 1908 t->scl_fall_ns, u); 1909 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u); 1910 i2c_parse_timing(dev, "i2c-digital-filter-width-ns", 1911 &t->digital_filter_width_ns, 0, u); 1912 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency", 1913 &t->analog_filter_cutoff_freq_hz, 0, u); 1914 } 1915 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); 1916 1917 /* ------------------------------------------------------------------------- */ 1918 1919 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data)) 1920 { 1921 int res; 1922 1923 mutex_lock(&core_lock); 1924 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn); 1925 mutex_unlock(&core_lock); 1926 1927 return res; 1928 } 1929 EXPORT_SYMBOL_GPL(i2c_for_each_dev); 1930 1931 static int __process_new_driver(struct device *dev, void *data) 1932 { 1933 if (dev->type != &i2c_adapter_type) 1934 return 0; 1935 return i2c_do_add_adapter(data, to_i2c_adapter(dev)); 1936 } 1937 1938 /* 1939 * An i2c_driver is used with one or more i2c_client (device) nodes to access 1940 * i2c slave chips, on a bus instance associated with some i2c_adapter. 1941 */ 1942 1943 int i2c_register_driver(struct module *owner, struct i2c_driver *driver) 1944 { 1945 int res; 1946 1947 /* Can't register until after driver model init */ 1948 if (WARN_ON(!is_registered)) 1949 return -EAGAIN; 1950 1951 /* add the driver to the list of i2c drivers in the driver core */ 1952 driver->driver.owner = owner; 1953 driver->driver.bus = &i2c_bus_type; 1954 INIT_LIST_HEAD(&driver->clients); 1955 1956 /* When registration returns, the driver core 1957 * will have called probe() for all matching-but-unbound devices. 1958 */ 1959 res = driver_register(&driver->driver); 1960 if (res) 1961 return res; 1962 1963 pr_debug("driver [%s] registered\n", driver->driver.name); 1964 1965 /* Walk the adapters that are already present */ 1966 i2c_for_each_dev(driver, __process_new_driver); 1967 1968 return 0; 1969 } 1970 EXPORT_SYMBOL(i2c_register_driver); 1971 1972 static int __process_removed_driver(struct device *dev, void *data) 1973 { 1974 if (dev->type == &i2c_adapter_type) 1975 i2c_do_del_adapter(data, to_i2c_adapter(dev)); 1976 return 0; 1977 } 1978 1979 /** 1980 * i2c_del_driver - unregister I2C driver 1981 * @driver: the driver being unregistered 1982 * Context: can sleep 1983 */ 1984 void i2c_del_driver(struct i2c_driver *driver) 1985 { 1986 i2c_for_each_dev(driver, __process_removed_driver); 1987 1988 driver_unregister(&driver->driver); 1989 pr_debug("driver [%s] unregistered\n", driver->driver.name); 1990 } 1991 EXPORT_SYMBOL(i2c_del_driver); 1992 1993 /* ------------------------------------------------------------------------- */ 1994 1995 struct i2c_cmd_arg { 1996 unsigned cmd; 1997 void *arg; 1998 }; 1999 2000 static int i2c_cmd(struct device *dev, void *_arg) 2001 { 2002 struct i2c_client *client = i2c_verify_client(dev); 2003 struct i2c_cmd_arg *arg = _arg; 2004 struct i2c_driver *driver; 2005 2006 if (!client || !client->dev.driver) 2007 return 0; 2008 2009 driver = to_i2c_driver(client->dev.driver); 2010 if (driver->command) 2011 driver->command(client, arg->cmd, arg->arg); 2012 return 0; 2013 } 2014 2015 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) 2016 { 2017 struct i2c_cmd_arg cmd_arg; 2018 2019 cmd_arg.cmd = cmd; 2020 cmd_arg.arg = arg; 2021 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); 2022 } 2023 EXPORT_SYMBOL(i2c_clients_command); 2024 2025 static int __init i2c_init(void) 2026 { 2027 int retval; 2028 2029 retval = of_alias_get_highest_id("i2c"); 2030 2031 down_write(&__i2c_board_lock); 2032 if (retval >= __i2c_first_dynamic_bus_num) 2033 __i2c_first_dynamic_bus_num = retval + 1; 2034 up_write(&__i2c_board_lock); 2035 2036 retval = bus_register(&i2c_bus_type); 2037 if (retval) 2038 return retval; 2039 2040 is_registered = true; 2041 2042 #ifdef CONFIG_I2C_COMPAT 2043 i2c_adapter_compat_class = class_compat_register("i2c-adapter"); 2044 if (!i2c_adapter_compat_class) { 2045 retval = -ENOMEM; 2046 goto bus_err; 2047 } 2048 #endif 2049 retval = i2c_add_driver(&dummy_driver); 2050 if (retval) 2051 goto class_err; 2052 2053 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 2054 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); 2055 if (IS_ENABLED(CONFIG_ACPI)) 2056 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier)); 2057 2058 return 0; 2059 2060 class_err: 2061 #ifdef CONFIG_I2C_COMPAT 2062 class_compat_unregister(i2c_adapter_compat_class); 2063 bus_err: 2064 #endif 2065 is_registered = false; 2066 bus_unregister(&i2c_bus_type); 2067 return retval; 2068 } 2069 2070 static void __exit i2c_exit(void) 2071 { 2072 if (IS_ENABLED(CONFIG_ACPI)) 2073 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier)); 2074 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 2075 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier)); 2076 i2c_del_driver(&dummy_driver); 2077 #ifdef CONFIG_I2C_COMPAT 2078 class_compat_unregister(i2c_adapter_compat_class); 2079 #endif 2080 bus_unregister(&i2c_bus_type); 2081 tracepoint_synchronize_unregister(); 2082 } 2083 2084 /* We must initialize early, because some subsystems register i2c drivers 2085 * in subsys_initcall() code, but are linked (and initialized) before i2c. 2086 */ 2087 postcore_initcall(i2c_init); 2088 module_exit(i2c_exit); 2089 2090 /* ---------------------------------------------------- 2091 * the functional interface to the i2c busses. 2092 * ---------------------------------------------------- 2093 */ 2094 2095 /* Check if val is exceeding the quirk IFF quirk is non 0 */ 2096 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) 2097 2098 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) 2099 { 2100 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n", 2101 err_msg, msg->addr, msg->len, 2102 msg->flags & I2C_M_RD ? "read" : "write"); 2103 return -EOPNOTSUPP; 2104 } 2105 2106 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2107 { 2108 const struct i2c_adapter_quirks *q = adap->quirks; 2109 int max_num = q->max_num_msgs, i; 2110 bool do_len_check = true; 2111 2112 if (q->flags & I2C_AQ_COMB) { 2113 max_num = 2; 2114 2115 /* special checks for combined messages */ 2116 if (num == 2) { 2117 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD) 2118 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write"); 2119 2120 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD)) 2121 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read"); 2122 2123 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr) 2124 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr"); 2125 2126 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len)) 2127 return i2c_quirk_error(adap, &msgs[0], "msg too long"); 2128 2129 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len)) 2130 return i2c_quirk_error(adap, &msgs[1], "msg too long"); 2131 2132 do_len_check = false; 2133 } 2134 } 2135 2136 if (i2c_quirk_exceeded(num, max_num)) 2137 return i2c_quirk_error(adap, &msgs[0], "too many messages"); 2138 2139 for (i = 0; i < num; i++) { 2140 u16 len = msgs[i].len; 2141 2142 if (msgs[i].flags & I2C_M_RD) { 2143 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len)) 2144 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2145 2146 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0) 2147 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2148 } else { 2149 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len)) 2150 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2151 2152 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0) 2153 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2154 } 2155 } 2156 2157 return 0; 2158 } 2159 2160 /** 2161 * __i2c_transfer - unlocked flavor of i2c_transfer 2162 * @adap: Handle to I2C bus 2163 * @msgs: One or more messages to execute before STOP is issued to 2164 * terminate the operation; each message begins with a START. 2165 * @num: Number of messages to be executed. 2166 * 2167 * Returns negative errno, else the number of messages executed. 2168 * 2169 * Adapter lock must be held when calling this function. No debug logging 2170 * takes place. adap->algo->master_xfer existence isn't checked. 2171 */ 2172 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2173 { 2174 unsigned long orig_jiffies; 2175 int ret, try; 2176 2177 if (WARN_ON(!msgs || num < 1)) 2178 return -EINVAL; 2179 2180 ret = __i2c_check_suspended(adap); 2181 if (ret) 2182 return ret; 2183 2184 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) 2185 return -EOPNOTSUPP; 2186 2187 /* 2188 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets 2189 * enabled. This is an efficient way of keeping the for-loop from 2190 * being executed when not needed. 2191 */ 2192 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2193 int i; 2194 for (i = 0; i < num; i++) 2195 if (msgs[i].flags & I2C_M_RD) 2196 trace_i2c_read(adap, &msgs[i], i); 2197 else 2198 trace_i2c_write(adap, &msgs[i], i); 2199 } 2200 2201 /* Retry automatically on arbitration loss */ 2202 orig_jiffies = jiffies; 2203 for (ret = 0, try = 0; try <= adap->retries; try++) { 2204 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic) 2205 ret = adap->algo->master_xfer_atomic(adap, msgs, num); 2206 else 2207 ret = adap->algo->master_xfer(adap, msgs, num); 2208 2209 if (ret != -EAGAIN) 2210 break; 2211 if (time_after(jiffies, orig_jiffies + adap->timeout)) 2212 break; 2213 } 2214 2215 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2216 int i; 2217 for (i = 0; i < ret; i++) 2218 if (msgs[i].flags & I2C_M_RD) 2219 trace_i2c_reply(adap, &msgs[i], i); 2220 trace_i2c_result(adap, num, ret); 2221 } 2222 2223 return ret; 2224 } 2225 EXPORT_SYMBOL(__i2c_transfer); 2226 2227 /** 2228 * i2c_transfer - execute a single or combined I2C message 2229 * @adap: Handle to I2C bus 2230 * @msgs: One or more messages to execute before STOP is issued to 2231 * terminate the operation; each message begins with a START. 2232 * @num: Number of messages to be executed. 2233 * 2234 * Returns negative errno, else the number of messages executed. 2235 * 2236 * Note that there is no requirement that each message be sent to 2237 * the same slave address, although that is the most common model. 2238 */ 2239 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2240 { 2241 int ret; 2242 2243 if (!adap->algo->master_xfer) { 2244 dev_dbg(&adap->dev, "I2C level transfers not supported\n"); 2245 return -EOPNOTSUPP; 2246 } 2247 2248 /* REVISIT the fault reporting model here is weak: 2249 * 2250 * - When we get an error after receiving N bytes from a slave, 2251 * there is no way to report "N". 2252 * 2253 * - When we get a NAK after transmitting N bytes to a slave, 2254 * there is no way to report "N" ... or to let the master 2255 * continue executing the rest of this combined message, if 2256 * that's the appropriate response. 2257 * 2258 * - When for example "num" is two and we successfully complete 2259 * the first message but get an error part way through the 2260 * second, it's unclear whether that should be reported as 2261 * one (discarding status on the second message) or errno 2262 * (discarding status on the first one). 2263 */ 2264 ret = __i2c_lock_bus_helper(adap); 2265 if (ret) 2266 return ret; 2267 2268 ret = __i2c_transfer(adap, msgs, num); 2269 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); 2270 2271 return ret; 2272 } 2273 EXPORT_SYMBOL(i2c_transfer); 2274 2275 /** 2276 * i2c_transfer_buffer_flags - issue a single I2C message transferring data 2277 * to/from a buffer 2278 * @client: Handle to slave device 2279 * @buf: Where the data is stored 2280 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16 2281 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads 2282 * 2283 * Returns negative errno, or else the number of bytes transferred. 2284 */ 2285 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf, 2286 int count, u16 flags) 2287 { 2288 int ret; 2289 struct i2c_msg msg = { 2290 .addr = client->addr, 2291 .flags = flags | (client->flags & I2C_M_TEN), 2292 .len = count, 2293 .buf = buf, 2294 }; 2295 2296 ret = i2c_transfer(client->adapter, &msg, 1); 2297 2298 /* 2299 * If everything went ok (i.e. 1 msg transferred), return #bytes 2300 * transferred, else error code. 2301 */ 2302 return (ret == 1) ? count : ret; 2303 } 2304 EXPORT_SYMBOL(i2c_transfer_buffer_flags); 2305 2306 /** 2307 * i2c_get_device_id - get manufacturer, part id and die revision of a device 2308 * @client: The device to query 2309 * @id: The queried information 2310 * 2311 * Returns negative errno on error, zero on success. 2312 */ 2313 int i2c_get_device_id(const struct i2c_client *client, 2314 struct i2c_device_identity *id) 2315 { 2316 struct i2c_adapter *adap = client->adapter; 2317 union i2c_smbus_data raw_id; 2318 int ret; 2319 2320 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) 2321 return -EOPNOTSUPP; 2322 2323 raw_id.block[0] = 3; 2324 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0, 2325 I2C_SMBUS_READ, client->addr << 1, 2326 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id); 2327 if (ret) 2328 return ret; 2329 2330 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4); 2331 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3); 2332 id->die_revision = raw_id.block[3] & 0x7; 2333 return 0; 2334 } 2335 EXPORT_SYMBOL_GPL(i2c_get_device_id); 2336 2337 /* ---------------------------------------------------- 2338 * the i2c address scanning function 2339 * Will not work for 10-bit addresses! 2340 * ---------------------------------------------------- 2341 */ 2342 2343 /* 2344 * Legacy default probe function, mostly relevant for SMBus. The default 2345 * probe method is a quick write, but it is known to corrupt the 24RF08 2346 * EEPROMs due to a state machine bug, and could also irreversibly 2347 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f, 2348 * we use a short byte read instead. Also, some bus drivers don't implement 2349 * quick write, so we fallback to a byte read in that case too. 2350 * On x86, there is another special case for FSC hardware monitoring chips, 2351 * which want regular byte reads (address 0x73.) Fortunately, these are the 2352 * only known chips using this I2C address on PC hardware. 2353 * Returns 1 if probe succeeded, 0 if not. 2354 */ 2355 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) 2356 { 2357 int err; 2358 union i2c_smbus_data dummy; 2359 2360 #ifdef CONFIG_X86 2361 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON) 2362 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA)) 2363 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2364 I2C_SMBUS_BYTE_DATA, &dummy); 2365 else 2366 #endif 2367 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) 2368 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) 2369 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, 2370 I2C_SMBUS_QUICK, NULL); 2371 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) 2372 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2373 I2C_SMBUS_BYTE, &dummy); 2374 else { 2375 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n", 2376 addr); 2377 err = -EOPNOTSUPP; 2378 } 2379 2380 return err >= 0; 2381 } 2382 2383 static int i2c_detect_address(struct i2c_client *temp_client, 2384 struct i2c_driver *driver) 2385 { 2386 struct i2c_board_info info; 2387 struct i2c_adapter *adapter = temp_client->adapter; 2388 int addr = temp_client->addr; 2389 int err; 2390 2391 /* Make sure the address is valid */ 2392 err = i2c_check_7bit_addr_validity_strict(addr); 2393 if (err) { 2394 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n", 2395 addr); 2396 return err; 2397 } 2398 2399 /* Skip if already in use (7 bit, no need to encode flags) */ 2400 if (i2c_check_addr_busy(adapter, addr)) 2401 return 0; 2402 2403 /* Make sure there is something at this address */ 2404 if (!i2c_default_probe(adapter, addr)) 2405 return 0; 2406 2407 /* Finally call the custom detection function */ 2408 memset(&info, 0, sizeof(struct i2c_board_info)); 2409 info.addr = addr; 2410 err = driver->detect(temp_client, &info); 2411 if (err) { 2412 /* -ENODEV is returned if the detection fails. We catch it 2413 here as this isn't an error. */ 2414 return err == -ENODEV ? 0 : err; 2415 } 2416 2417 /* Consistency check */ 2418 if (info.type[0] == '\0') { 2419 dev_err(&adapter->dev, 2420 "%s detection function provided no name for 0x%x\n", 2421 driver->driver.name, addr); 2422 } else { 2423 struct i2c_client *client; 2424 2425 /* Detection succeeded, instantiate the device */ 2426 if (adapter->class & I2C_CLASS_DEPRECATED) 2427 dev_warn(&adapter->dev, 2428 "This adapter will soon drop class based instantiation of devices. " 2429 "Please make sure client 0x%02x gets instantiated by other means. " 2430 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n", 2431 info.addr); 2432 2433 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n", 2434 info.type, info.addr); 2435 client = i2c_new_client_device(adapter, &info); 2436 if (!IS_ERR(client)) 2437 list_add_tail(&client->detected, &driver->clients); 2438 else 2439 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n", 2440 info.type, info.addr); 2441 } 2442 return 0; 2443 } 2444 2445 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) 2446 { 2447 const unsigned short *address_list; 2448 struct i2c_client *temp_client; 2449 int i, err = 0; 2450 2451 address_list = driver->address_list; 2452 if (!driver->detect || !address_list) 2453 return 0; 2454 2455 /* Warn that the adapter lost class based instantiation */ 2456 if (adapter->class == I2C_CLASS_DEPRECATED) { 2457 dev_dbg(&adapter->dev, 2458 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. " 2459 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n", 2460 driver->driver.name); 2461 return 0; 2462 } 2463 2464 /* Stop here if the classes do not match */ 2465 if (!(adapter->class & driver->class)) 2466 return 0; 2467 2468 /* Set up a temporary client to help detect callback */ 2469 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); 2470 if (!temp_client) 2471 return -ENOMEM; 2472 temp_client->adapter = adapter; 2473 2474 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { 2475 dev_dbg(&adapter->dev, 2476 "found normal entry for adapter %d, addr 0x%02x\n", 2477 i2c_adapter_id(adapter), address_list[i]); 2478 temp_client->addr = address_list[i]; 2479 err = i2c_detect_address(temp_client, driver); 2480 if (unlikely(err)) 2481 break; 2482 } 2483 2484 kfree(temp_client); 2485 return err; 2486 } 2487 2488 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) 2489 { 2490 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2491 I2C_SMBUS_QUICK, NULL) >= 0; 2492 } 2493 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); 2494 2495 struct i2c_client * 2496 i2c_new_scanned_device(struct i2c_adapter *adap, 2497 struct i2c_board_info *info, 2498 unsigned short const *addr_list, 2499 int (*probe)(struct i2c_adapter *adap, unsigned short addr)) 2500 { 2501 int i; 2502 2503 if (!probe) 2504 probe = i2c_default_probe; 2505 2506 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { 2507 /* Check address validity */ 2508 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) { 2509 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n", 2510 addr_list[i]); 2511 continue; 2512 } 2513 2514 /* Check address availability (7 bit, no need to encode flags) */ 2515 if (i2c_check_addr_busy(adap, addr_list[i])) { 2516 dev_dbg(&adap->dev, 2517 "Address 0x%02x already in use, not probing\n", 2518 addr_list[i]); 2519 continue; 2520 } 2521 2522 /* Test address responsiveness */ 2523 if (probe(adap, addr_list[i])) 2524 break; 2525 } 2526 2527 if (addr_list[i] == I2C_CLIENT_END) { 2528 dev_dbg(&adap->dev, "Probing failed, no device found\n"); 2529 return ERR_PTR(-ENODEV); 2530 } 2531 2532 info->addr = addr_list[i]; 2533 return i2c_new_client_device(adap, info); 2534 } 2535 EXPORT_SYMBOL_GPL(i2c_new_scanned_device); 2536 2537 struct i2c_adapter *i2c_get_adapter(int nr) 2538 { 2539 struct i2c_adapter *adapter; 2540 2541 mutex_lock(&core_lock); 2542 adapter = idr_find(&i2c_adapter_idr, nr); 2543 if (!adapter) 2544 goto exit; 2545 2546 if (try_module_get(adapter->owner)) 2547 get_device(&adapter->dev); 2548 else 2549 adapter = NULL; 2550 2551 exit: 2552 mutex_unlock(&core_lock); 2553 return adapter; 2554 } 2555 EXPORT_SYMBOL(i2c_get_adapter); 2556 2557 void i2c_put_adapter(struct i2c_adapter *adap) 2558 { 2559 if (!adap) 2560 return; 2561 2562 put_device(&adap->dev); 2563 module_put(adap->owner); 2564 } 2565 EXPORT_SYMBOL(i2c_put_adapter); 2566 2567 /** 2568 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg 2569 * @msg: the message to be checked 2570 * @threshold: the minimum number of bytes for which using DMA makes sense. 2571 * Should at least be 1. 2572 * 2573 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO. 2574 * Or a valid pointer to be used with DMA. After use, release it by 2575 * calling i2c_put_dma_safe_msg_buf(). 2576 * 2577 * This function must only be called from process context! 2578 */ 2579 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold) 2580 { 2581 /* also skip 0-length msgs for bogus thresholds of 0 */ 2582 if (!threshold) 2583 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n", 2584 msg->addr); 2585 if (msg->len < threshold || msg->len == 0) 2586 return NULL; 2587 2588 if (msg->flags & I2C_M_DMA_SAFE) 2589 return msg->buf; 2590 2591 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n", 2592 msg->addr, msg->len); 2593 2594 if (msg->flags & I2C_M_RD) 2595 return kzalloc(msg->len, GFP_KERNEL); 2596 else 2597 return kmemdup(msg->buf, msg->len, GFP_KERNEL); 2598 } 2599 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf); 2600 2601 /** 2602 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg 2603 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL. 2604 * @msg: the message which the buffer corresponds to 2605 * @xferred: bool saying if the message was transferred 2606 */ 2607 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred) 2608 { 2609 if (!buf || buf == msg->buf) 2610 return; 2611 2612 if (xferred && msg->flags & I2C_M_RD) 2613 memcpy(msg->buf, buf, msg->len); 2614 2615 kfree(buf); 2616 } 2617 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf); 2618 2619 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 2620 MODULE_DESCRIPTION("I2C-Bus main module"); 2621 MODULE_LICENSE("GPL"); 2622