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 int 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 /* return always 0 because there is WIP to make remove-functions void */ 636 return 0; 637 } 638 639 #ifdef CONFIG_PM_SLEEP 640 static int i2c_resume_early(struct device *dev) 641 { 642 struct i2c_client *client = i2c_verify_client(dev); 643 int err; 644 645 if (!client) 646 return 0; 647 648 if (pm_runtime_status_suspended(&client->dev) && 649 client->adapter->bus_regulator) { 650 err = regulator_enable(client->adapter->bus_regulator); 651 if (err) 652 return err; 653 } 654 655 return pm_generic_resume_early(&client->dev); 656 } 657 658 static int i2c_suspend_late(struct device *dev) 659 { 660 struct i2c_client *client = i2c_verify_client(dev); 661 int err; 662 663 if (!client) 664 return 0; 665 666 err = pm_generic_suspend_late(&client->dev); 667 if (err) 668 return err; 669 670 if (!pm_runtime_status_suspended(&client->dev) && 671 client->adapter->bus_regulator) 672 return regulator_disable(client->adapter->bus_regulator); 673 674 return 0; 675 } 676 #endif 677 678 #ifdef CONFIG_PM 679 static int i2c_runtime_resume(struct device *dev) 680 { 681 struct i2c_client *client = i2c_verify_client(dev); 682 int err; 683 684 if (!client) 685 return 0; 686 687 if (client->adapter->bus_regulator) { 688 err = regulator_enable(client->adapter->bus_regulator); 689 if (err) 690 return err; 691 } 692 693 return pm_generic_runtime_resume(&client->dev); 694 } 695 696 static int i2c_runtime_suspend(struct device *dev) 697 { 698 struct i2c_client *client = i2c_verify_client(dev); 699 int err; 700 701 if (!client) 702 return 0; 703 704 err = pm_generic_runtime_suspend(&client->dev); 705 if (err) 706 return err; 707 708 if (client->adapter->bus_regulator) 709 return regulator_disable(client->adapter->bus_regulator); 710 return 0; 711 } 712 #endif 713 714 static const struct dev_pm_ops i2c_device_pm = { 715 SET_LATE_SYSTEM_SLEEP_PM_OPS(i2c_suspend_late, i2c_resume_early) 716 SET_RUNTIME_PM_OPS(i2c_runtime_suspend, i2c_runtime_resume, NULL) 717 }; 718 719 static void i2c_device_shutdown(struct device *dev) 720 { 721 struct i2c_client *client = i2c_verify_client(dev); 722 struct i2c_driver *driver; 723 724 if (!client || !dev->driver) 725 return; 726 driver = to_i2c_driver(dev->driver); 727 if (driver->shutdown) 728 driver->shutdown(client); 729 else if (client->irq > 0) 730 disable_irq(client->irq); 731 } 732 733 static void i2c_client_dev_release(struct device *dev) 734 { 735 kfree(to_i2c_client(dev)); 736 } 737 738 static ssize_t 739 name_show(struct device *dev, struct device_attribute *attr, char *buf) 740 { 741 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? 742 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); 743 } 744 static DEVICE_ATTR_RO(name); 745 746 static ssize_t 747 modalias_show(struct device *dev, struct device_attribute *attr, char *buf) 748 { 749 struct i2c_client *client = to_i2c_client(dev); 750 int len; 751 752 len = of_device_modalias(dev, buf, PAGE_SIZE); 753 if (len != -ENODEV) 754 return len; 755 756 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); 757 if (len != -ENODEV) 758 return len; 759 760 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); 761 } 762 static DEVICE_ATTR_RO(modalias); 763 764 static struct attribute *i2c_dev_attrs[] = { 765 &dev_attr_name.attr, 766 /* modalias helps coldplug: modprobe $(cat .../modalias) */ 767 &dev_attr_modalias.attr, 768 NULL 769 }; 770 ATTRIBUTE_GROUPS(i2c_dev); 771 772 struct bus_type i2c_bus_type = { 773 .name = "i2c", 774 .match = i2c_device_match, 775 .probe = i2c_device_probe, 776 .remove = i2c_device_remove, 777 .shutdown = i2c_device_shutdown, 778 .pm = &i2c_device_pm, 779 }; 780 EXPORT_SYMBOL_GPL(i2c_bus_type); 781 782 struct device_type i2c_client_type = { 783 .groups = i2c_dev_groups, 784 .uevent = i2c_device_uevent, 785 .release = i2c_client_dev_release, 786 }; 787 EXPORT_SYMBOL_GPL(i2c_client_type); 788 789 790 /** 791 * i2c_verify_client - return parameter as i2c_client, or NULL 792 * @dev: device, probably from some driver model iterator 793 * 794 * When traversing the driver model tree, perhaps using driver model 795 * iterators like @device_for_each_child(), you can't assume very much 796 * about the nodes you find. Use this function to avoid oopses caused 797 * by wrongly treating some non-I2C device as an i2c_client. 798 */ 799 struct i2c_client *i2c_verify_client(struct device *dev) 800 { 801 return (dev->type == &i2c_client_type) 802 ? to_i2c_client(dev) 803 : NULL; 804 } 805 EXPORT_SYMBOL(i2c_verify_client); 806 807 808 /* Return a unique address which takes the flags of the client into account */ 809 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client) 810 { 811 unsigned short addr = client->addr; 812 813 /* For some client flags, add an arbitrary offset to avoid collisions */ 814 if (client->flags & I2C_CLIENT_TEN) 815 addr |= I2C_ADDR_OFFSET_TEN_BIT; 816 817 if (client->flags & I2C_CLIENT_SLAVE) 818 addr |= I2C_ADDR_OFFSET_SLAVE; 819 820 return addr; 821 } 822 823 /* This is a permissive address validity check, I2C address map constraints 824 * are purposely not enforced, except for the general call address. */ 825 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags) 826 { 827 if (flags & I2C_CLIENT_TEN) { 828 /* 10-bit address, all values are valid */ 829 if (addr > 0x3ff) 830 return -EINVAL; 831 } else { 832 /* 7-bit address, reject the general call address */ 833 if (addr == 0x00 || addr > 0x7f) 834 return -EINVAL; 835 } 836 return 0; 837 } 838 839 /* And this is a strict address validity check, used when probing. If a 840 * device uses a reserved address, then it shouldn't be probed. 7-bit 841 * addressing is assumed, 10-bit address devices are rare and should be 842 * explicitly enumerated. */ 843 int i2c_check_7bit_addr_validity_strict(unsigned short addr) 844 { 845 /* 846 * Reserved addresses per I2C specification: 847 * 0x00 General call address / START byte 848 * 0x01 CBUS address 849 * 0x02 Reserved for different bus format 850 * 0x03 Reserved for future purposes 851 * 0x04-0x07 Hs-mode master code 852 * 0x78-0x7b 10-bit slave addressing 853 * 0x7c-0x7f Reserved for future purposes 854 */ 855 if (addr < 0x08 || addr > 0x77) 856 return -EINVAL; 857 return 0; 858 } 859 860 static int __i2c_check_addr_busy(struct device *dev, void *addrp) 861 { 862 struct i2c_client *client = i2c_verify_client(dev); 863 int addr = *(int *)addrp; 864 865 if (client && i2c_encode_flags_to_addr(client) == addr) 866 return -EBUSY; 867 return 0; 868 } 869 870 /* walk up mux tree */ 871 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) 872 { 873 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 874 int result; 875 876 result = device_for_each_child(&adapter->dev, &addr, 877 __i2c_check_addr_busy); 878 879 if (!result && parent) 880 result = i2c_check_mux_parents(parent, addr); 881 882 return result; 883 } 884 885 /* recurse down mux tree */ 886 static int i2c_check_mux_children(struct device *dev, void *addrp) 887 { 888 int result; 889 890 if (dev->type == &i2c_adapter_type) 891 result = device_for_each_child(dev, addrp, 892 i2c_check_mux_children); 893 else 894 result = __i2c_check_addr_busy(dev, addrp); 895 896 return result; 897 } 898 899 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) 900 { 901 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 902 int result = 0; 903 904 if (parent) 905 result = i2c_check_mux_parents(parent, addr); 906 907 if (!result) 908 result = device_for_each_child(&adapter->dev, &addr, 909 i2c_check_mux_children); 910 911 return result; 912 } 913 914 /** 915 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment 916 * @adapter: Target I2C bus segment 917 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT 918 * locks only this branch in the adapter tree 919 */ 920 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, 921 unsigned int flags) 922 { 923 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); 924 } 925 926 /** 927 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment 928 * @adapter: Target I2C bus segment 929 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT 930 * trylocks only this branch in the adapter tree 931 */ 932 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, 933 unsigned int flags) 934 { 935 return rt_mutex_trylock(&adapter->bus_lock); 936 } 937 938 /** 939 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment 940 * @adapter: Target I2C bus segment 941 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT 942 * unlocks only this branch in the adapter tree 943 */ 944 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, 945 unsigned int flags) 946 { 947 rt_mutex_unlock(&adapter->bus_lock); 948 } 949 950 static void i2c_dev_set_name(struct i2c_adapter *adap, 951 struct i2c_client *client, 952 struct i2c_board_info const *info) 953 { 954 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 955 956 if (info && info->dev_name) { 957 dev_set_name(&client->dev, "i2c-%s", info->dev_name); 958 return; 959 } 960 961 if (adev) { 962 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev)); 963 return; 964 } 965 966 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), 967 i2c_encode_flags_to_addr(client)); 968 } 969 970 int i2c_dev_irq_from_resources(const struct resource *resources, 971 unsigned int num_resources) 972 { 973 struct irq_data *irqd; 974 int i; 975 976 for (i = 0; i < num_resources; i++) { 977 const struct resource *r = &resources[i]; 978 979 if (resource_type(r) != IORESOURCE_IRQ) 980 continue; 981 982 if (r->flags & IORESOURCE_BITS) { 983 irqd = irq_get_irq_data(r->start); 984 if (!irqd) 985 break; 986 987 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); 988 } 989 990 return r->start; 991 } 992 993 return 0; 994 } 995 996 /** 997 * i2c_new_client_device - instantiate an i2c device 998 * @adap: the adapter managing the device 999 * @info: describes one I2C device; bus_num is ignored 1000 * Context: can sleep 1001 * 1002 * Create an i2c device. Binding is handled through driver model 1003 * probe()/remove() methods. A driver may be bound to this device when we 1004 * return from this function, or any later moment (e.g. maybe hotplugging will 1005 * load the driver module). This call is not appropriate for use by mainboard 1006 * initialization logic, which usually runs during an arch_initcall() long 1007 * before any i2c_adapter could exist. 1008 * 1009 * This returns the new i2c client, which may be saved for later use with 1010 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1011 */ 1012 struct i2c_client * 1013 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info) 1014 { 1015 struct i2c_client *client; 1016 int status; 1017 1018 client = kzalloc(sizeof *client, GFP_KERNEL); 1019 if (!client) 1020 return ERR_PTR(-ENOMEM); 1021 1022 client->adapter = adap; 1023 1024 client->dev.platform_data = info->platform_data; 1025 client->flags = info->flags; 1026 client->addr = info->addr; 1027 1028 client->init_irq = info->irq; 1029 if (!client->init_irq) 1030 client->init_irq = i2c_dev_irq_from_resources(info->resources, 1031 info->num_resources); 1032 1033 strlcpy(client->name, info->type, sizeof(client->name)); 1034 1035 status = i2c_check_addr_validity(client->addr, client->flags); 1036 if (status) { 1037 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", 1038 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); 1039 goto out_err_silent; 1040 } 1041 1042 /* Check for address business */ 1043 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); 1044 if (status) 1045 goto out_err; 1046 1047 client->dev.parent = &client->adapter->dev; 1048 client->dev.bus = &i2c_bus_type; 1049 client->dev.type = &i2c_client_type; 1050 client->dev.of_node = of_node_get(info->of_node); 1051 client->dev.fwnode = info->fwnode; 1052 1053 i2c_dev_set_name(adap, client, info); 1054 1055 if (info->swnode) { 1056 status = device_add_software_node(&client->dev, info->swnode); 1057 if (status) { 1058 dev_err(&adap->dev, 1059 "Failed to add software node to client %s: %d\n", 1060 client->name, status); 1061 goto out_err_put_of_node; 1062 } 1063 } 1064 1065 status = device_register(&client->dev); 1066 if (status) 1067 goto out_remove_swnode; 1068 1069 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", 1070 client->name, dev_name(&client->dev)); 1071 1072 return client; 1073 1074 out_remove_swnode: 1075 device_remove_software_node(&client->dev); 1076 out_err_put_of_node: 1077 of_node_put(info->of_node); 1078 out_err: 1079 dev_err(&adap->dev, 1080 "Failed to register i2c client %s at 0x%02x (%d)\n", 1081 client->name, client->addr, status); 1082 out_err_silent: 1083 kfree(client); 1084 return ERR_PTR(status); 1085 } 1086 EXPORT_SYMBOL_GPL(i2c_new_client_device); 1087 1088 /** 1089 * i2c_unregister_device - reverse effect of i2c_new_*_device() 1090 * @client: value returned from i2c_new_*_device() 1091 * Context: can sleep 1092 */ 1093 void i2c_unregister_device(struct i2c_client *client) 1094 { 1095 if (IS_ERR_OR_NULL(client)) 1096 return; 1097 1098 if (client->dev.of_node) { 1099 of_node_clear_flag(client->dev.of_node, OF_POPULATED); 1100 of_node_put(client->dev.of_node); 1101 } 1102 1103 if (ACPI_COMPANION(&client->dev)) 1104 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev)); 1105 device_remove_software_node(&client->dev); 1106 device_unregister(&client->dev); 1107 } 1108 EXPORT_SYMBOL_GPL(i2c_unregister_device); 1109 1110 1111 static const struct i2c_device_id dummy_id[] = { 1112 { "dummy", 0 }, 1113 { }, 1114 }; 1115 1116 static int dummy_probe(struct i2c_client *client, 1117 const struct i2c_device_id *id) 1118 { 1119 return 0; 1120 } 1121 1122 static int dummy_remove(struct i2c_client *client) 1123 { 1124 return 0; 1125 } 1126 1127 static struct i2c_driver dummy_driver = { 1128 .driver.name = "dummy", 1129 .probe = dummy_probe, 1130 .remove = dummy_remove, 1131 .id_table = dummy_id, 1132 }; 1133 1134 /** 1135 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1136 * @adapter: the adapter managing the device 1137 * @address: seven bit address to be used 1138 * Context: can sleep 1139 * 1140 * This returns an I2C client bound to the "dummy" driver, intended for use 1141 * with devices that consume multiple addresses. Examples of such chips 1142 * include various EEPROMS (like 24c04 and 24c08 models). 1143 * 1144 * These dummy devices have two main uses. First, most I2C and SMBus calls 1145 * except i2c_transfer() need a client handle; the dummy will be that handle. 1146 * And second, this prevents the specified address from being bound to a 1147 * different driver. 1148 * 1149 * This returns the new i2c client, which should be saved for later use with 1150 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1151 */ 1152 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address) 1153 { 1154 struct i2c_board_info info = { 1155 I2C_BOARD_INFO("dummy", address), 1156 }; 1157 1158 return i2c_new_client_device(adapter, &info); 1159 } 1160 EXPORT_SYMBOL_GPL(i2c_new_dummy_device); 1161 1162 static void devm_i2c_release_dummy(void *client) 1163 { 1164 i2c_unregister_device(client); 1165 } 1166 1167 /** 1168 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1169 * @dev: device the managed resource is bound to 1170 * @adapter: the adapter managing the device 1171 * @address: seven bit address to be used 1172 * Context: can sleep 1173 * 1174 * This is the device-managed version of @i2c_new_dummy_device. It returns the 1175 * new i2c client or an ERR_PTR in case of an error. 1176 */ 1177 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev, 1178 struct i2c_adapter *adapter, 1179 u16 address) 1180 { 1181 struct i2c_client *client; 1182 int ret; 1183 1184 client = i2c_new_dummy_device(adapter, address); 1185 if (IS_ERR(client)) 1186 return client; 1187 1188 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client); 1189 if (ret) 1190 return ERR_PTR(ret); 1191 1192 return client; 1193 } 1194 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device); 1195 1196 /** 1197 * i2c_new_ancillary_device - Helper to get the instantiated secondary address 1198 * and create the associated device 1199 * @client: Handle to the primary client 1200 * @name: Handle to specify which secondary address to get 1201 * @default_addr: Used as a fallback if no secondary address was specified 1202 * Context: can sleep 1203 * 1204 * I2C clients can be composed of multiple I2C slaves bound together in a single 1205 * component. The I2C client driver then binds to the master I2C slave and needs 1206 * to create I2C dummy clients to communicate with all the other slaves. 1207 * 1208 * This function creates and returns an I2C dummy client whose I2C address is 1209 * retrieved from the platform firmware based on the given slave name. If no 1210 * address is specified by the firmware default_addr is used. 1211 * 1212 * On DT-based platforms the address is retrieved from the "reg" property entry 1213 * cell whose "reg-names" value matches the slave name. 1214 * 1215 * This returns the new i2c client, which should be saved for later use with 1216 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1217 */ 1218 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, 1219 const char *name, 1220 u16 default_addr) 1221 { 1222 struct device_node *np = client->dev.of_node; 1223 u32 addr = default_addr; 1224 int i; 1225 1226 if (np) { 1227 i = of_property_match_string(np, "reg-names", name); 1228 if (i >= 0) 1229 of_property_read_u32_index(np, "reg", i, &addr); 1230 } 1231 1232 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); 1233 return i2c_new_dummy_device(client->adapter, addr); 1234 } 1235 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device); 1236 1237 /* ------------------------------------------------------------------------- */ 1238 1239 /* I2C bus adapters -- one roots each I2C or SMBUS segment */ 1240 1241 static void i2c_adapter_dev_release(struct device *dev) 1242 { 1243 struct i2c_adapter *adap = to_i2c_adapter(dev); 1244 complete(&adap->dev_released); 1245 } 1246 1247 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) 1248 { 1249 unsigned int depth = 0; 1250 1251 while ((adapter = i2c_parent_is_i2c_adapter(adapter))) 1252 depth++; 1253 1254 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES, 1255 "adapter depth exceeds lockdep subclass limit\n"); 1256 1257 return depth; 1258 } 1259 EXPORT_SYMBOL_GPL(i2c_adapter_depth); 1260 1261 /* 1262 * Let users instantiate I2C devices through sysfs. This can be used when 1263 * platform initialization code doesn't contain the proper data for 1264 * whatever reason. Also useful for drivers that do device detection and 1265 * detection fails, either because the device uses an unexpected address, 1266 * or this is a compatible device with different ID register values. 1267 * 1268 * Parameter checking may look overzealous, but we really don't want 1269 * the user to provide incorrect parameters. 1270 */ 1271 static ssize_t 1272 new_device_store(struct device *dev, struct device_attribute *attr, 1273 const char *buf, size_t count) 1274 { 1275 struct i2c_adapter *adap = to_i2c_adapter(dev); 1276 struct i2c_board_info info; 1277 struct i2c_client *client; 1278 char *blank, end; 1279 int res; 1280 1281 memset(&info, 0, sizeof(struct i2c_board_info)); 1282 1283 blank = strchr(buf, ' '); 1284 if (!blank) { 1285 dev_err(dev, "%s: Missing parameters\n", "new_device"); 1286 return -EINVAL; 1287 } 1288 if (blank - buf > I2C_NAME_SIZE - 1) { 1289 dev_err(dev, "%s: Invalid device name\n", "new_device"); 1290 return -EINVAL; 1291 } 1292 memcpy(info.type, buf, blank - buf); 1293 1294 /* Parse remaining parameters, reject extra parameters */ 1295 res = sscanf(++blank, "%hi%c", &info.addr, &end); 1296 if (res < 1) { 1297 dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); 1298 return -EINVAL; 1299 } 1300 if (res > 1 && end != '\n') { 1301 dev_err(dev, "%s: Extra parameters\n", "new_device"); 1302 return -EINVAL; 1303 } 1304 1305 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) { 1306 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT; 1307 info.flags |= I2C_CLIENT_TEN; 1308 } 1309 1310 if (info.addr & I2C_ADDR_OFFSET_SLAVE) { 1311 info.addr &= ~I2C_ADDR_OFFSET_SLAVE; 1312 info.flags |= I2C_CLIENT_SLAVE; 1313 } 1314 1315 client = i2c_new_client_device(adap, &info); 1316 if (IS_ERR(client)) 1317 return PTR_ERR(client); 1318 1319 /* Keep track of the added device */ 1320 mutex_lock(&adap->userspace_clients_lock); 1321 list_add_tail(&client->detected, &adap->userspace_clients); 1322 mutex_unlock(&adap->userspace_clients_lock); 1323 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", 1324 info.type, info.addr); 1325 1326 return count; 1327 } 1328 static DEVICE_ATTR_WO(new_device); 1329 1330 /* 1331 * And of course let the users delete the devices they instantiated, if 1332 * they got it wrong. This interface can only be used to delete devices 1333 * instantiated by i2c_sysfs_new_device above. This guarantees that we 1334 * don't delete devices to which some kernel code still has references. 1335 * 1336 * Parameter checking may look overzealous, but we really don't want 1337 * the user to delete the wrong device. 1338 */ 1339 static ssize_t 1340 delete_device_store(struct device *dev, struct device_attribute *attr, 1341 const char *buf, size_t count) 1342 { 1343 struct i2c_adapter *adap = to_i2c_adapter(dev); 1344 struct i2c_client *client, *next; 1345 unsigned short addr; 1346 char end; 1347 int res; 1348 1349 /* Parse parameters, reject extra parameters */ 1350 res = sscanf(buf, "%hi%c", &addr, &end); 1351 if (res < 1) { 1352 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); 1353 return -EINVAL; 1354 } 1355 if (res > 1 && end != '\n') { 1356 dev_err(dev, "%s: Extra parameters\n", "delete_device"); 1357 return -EINVAL; 1358 } 1359 1360 /* Make sure the device was added through sysfs */ 1361 res = -ENOENT; 1362 mutex_lock_nested(&adap->userspace_clients_lock, 1363 i2c_adapter_depth(adap)); 1364 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1365 detected) { 1366 if (i2c_encode_flags_to_addr(client) == addr) { 1367 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", 1368 "delete_device", client->name, client->addr); 1369 1370 list_del(&client->detected); 1371 i2c_unregister_device(client); 1372 res = count; 1373 break; 1374 } 1375 } 1376 mutex_unlock(&adap->userspace_clients_lock); 1377 1378 if (res < 0) 1379 dev_err(dev, "%s: Can't find device in list\n", 1380 "delete_device"); 1381 return res; 1382 } 1383 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL, 1384 delete_device_store); 1385 1386 static struct attribute *i2c_adapter_attrs[] = { 1387 &dev_attr_name.attr, 1388 &dev_attr_new_device.attr, 1389 &dev_attr_delete_device.attr, 1390 NULL 1391 }; 1392 ATTRIBUTE_GROUPS(i2c_adapter); 1393 1394 struct device_type i2c_adapter_type = { 1395 .groups = i2c_adapter_groups, 1396 .release = i2c_adapter_dev_release, 1397 }; 1398 EXPORT_SYMBOL_GPL(i2c_adapter_type); 1399 1400 /** 1401 * i2c_verify_adapter - return parameter as i2c_adapter or NULL 1402 * @dev: device, probably from some driver model iterator 1403 * 1404 * When traversing the driver model tree, perhaps using driver model 1405 * iterators like @device_for_each_child(), you can't assume very much 1406 * about the nodes you find. Use this function to avoid oopses caused 1407 * by wrongly treating some non-I2C device as an i2c_adapter. 1408 */ 1409 struct i2c_adapter *i2c_verify_adapter(struct device *dev) 1410 { 1411 return (dev->type == &i2c_adapter_type) 1412 ? to_i2c_adapter(dev) 1413 : NULL; 1414 } 1415 EXPORT_SYMBOL(i2c_verify_adapter); 1416 1417 #ifdef CONFIG_I2C_COMPAT 1418 static struct class_compat *i2c_adapter_compat_class; 1419 #endif 1420 1421 static void i2c_scan_static_board_info(struct i2c_adapter *adapter) 1422 { 1423 struct i2c_devinfo *devinfo; 1424 1425 down_read(&__i2c_board_lock); 1426 list_for_each_entry(devinfo, &__i2c_board_list, list) { 1427 if (devinfo->busnum == adapter->nr && 1428 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info))) 1429 dev_err(&adapter->dev, 1430 "Can't create device at 0x%02x\n", 1431 devinfo->board_info.addr); 1432 } 1433 up_read(&__i2c_board_lock); 1434 } 1435 1436 static int i2c_do_add_adapter(struct i2c_driver *driver, 1437 struct i2c_adapter *adap) 1438 { 1439 /* Detect supported devices on that bus, and instantiate them */ 1440 i2c_detect(adap, driver); 1441 1442 return 0; 1443 } 1444 1445 static int __process_new_adapter(struct device_driver *d, void *data) 1446 { 1447 return i2c_do_add_adapter(to_i2c_driver(d), data); 1448 } 1449 1450 static const struct i2c_lock_operations i2c_adapter_lock_ops = { 1451 .lock_bus = i2c_adapter_lock_bus, 1452 .trylock_bus = i2c_adapter_trylock_bus, 1453 .unlock_bus = i2c_adapter_unlock_bus, 1454 }; 1455 1456 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap) 1457 { 1458 struct irq_domain *domain = adap->host_notify_domain; 1459 irq_hw_number_t hwirq; 1460 1461 if (!domain) 1462 return; 1463 1464 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++) 1465 irq_dispose_mapping(irq_find_mapping(domain, hwirq)); 1466 1467 irq_domain_remove(domain); 1468 adap->host_notify_domain = NULL; 1469 } 1470 1471 static int i2c_host_notify_irq_map(struct irq_domain *h, 1472 unsigned int virq, 1473 irq_hw_number_t hw_irq_num) 1474 { 1475 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq); 1476 1477 return 0; 1478 } 1479 1480 static const struct irq_domain_ops i2c_host_notify_irq_ops = { 1481 .map = i2c_host_notify_irq_map, 1482 }; 1483 1484 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap) 1485 { 1486 struct irq_domain *domain; 1487 1488 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY)) 1489 return 0; 1490 1491 domain = irq_domain_create_linear(adap->dev.parent->fwnode, 1492 I2C_ADDR_7BITS_COUNT, 1493 &i2c_host_notify_irq_ops, adap); 1494 if (!domain) 1495 return -ENOMEM; 1496 1497 adap->host_notify_domain = domain; 1498 1499 return 0; 1500 } 1501 1502 /** 1503 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct 1504 * I2C client. 1505 * @adap: the adapter 1506 * @addr: the I2C address of the notifying device 1507 * Context: can't sleep 1508 * 1509 * Helper function to be called from an I2C bus driver's interrupt 1510 * handler. It will schedule the Host Notify IRQ. 1511 */ 1512 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr) 1513 { 1514 int irq; 1515 1516 if (!adap) 1517 return -EINVAL; 1518 1519 irq = irq_find_mapping(adap->host_notify_domain, addr); 1520 if (irq <= 0) 1521 return -ENXIO; 1522 1523 generic_handle_irq(irq); 1524 1525 return 0; 1526 } 1527 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify); 1528 1529 static int i2c_register_adapter(struct i2c_adapter *adap) 1530 { 1531 int res = -EINVAL; 1532 1533 /* Can't register until after driver model init */ 1534 if (WARN_ON(!is_registered)) { 1535 res = -EAGAIN; 1536 goto out_list; 1537 } 1538 1539 /* Sanity checks */ 1540 if (WARN(!adap->name[0], "i2c adapter has no name")) 1541 goto out_list; 1542 1543 if (!adap->algo) { 1544 pr_err("adapter '%s': no algo supplied!\n", adap->name); 1545 goto out_list; 1546 } 1547 1548 if (!adap->lock_ops) 1549 adap->lock_ops = &i2c_adapter_lock_ops; 1550 1551 adap->locked_flags = 0; 1552 rt_mutex_init(&adap->bus_lock); 1553 rt_mutex_init(&adap->mux_lock); 1554 mutex_init(&adap->userspace_clients_lock); 1555 INIT_LIST_HEAD(&adap->userspace_clients); 1556 1557 /* Set default timeout to 1 second if not already set */ 1558 if (adap->timeout == 0) 1559 adap->timeout = HZ; 1560 1561 /* register soft irqs for Host Notify */ 1562 res = i2c_setup_host_notify_irq_domain(adap); 1563 if (res) { 1564 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n", 1565 adap->name, res); 1566 goto out_list; 1567 } 1568 1569 dev_set_name(&adap->dev, "i2c-%d", adap->nr); 1570 adap->dev.bus = &i2c_bus_type; 1571 adap->dev.type = &i2c_adapter_type; 1572 res = device_register(&adap->dev); 1573 if (res) { 1574 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); 1575 goto out_list; 1576 } 1577 1578 res = of_i2c_setup_smbus_alert(adap); 1579 if (res) 1580 goto out_reg; 1581 1582 pm_runtime_no_callbacks(&adap->dev); 1583 pm_suspend_ignore_children(&adap->dev, true); 1584 pm_runtime_enable(&adap->dev); 1585 1586 res = i2c_init_recovery(adap); 1587 if (res == -EPROBE_DEFER) 1588 goto out_reg; 1589 1590 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); 1591 1592 #ifdef CONFIG_I2C_COMPAT 1593 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, 1594 adap->dev.parent); 1595 if (res) 1596 dev_warn(&adap->dev, 1597 "Failed to create compatibility class link\n"); 1598 #endif 1599 1600 /* create pre-declared device nodes */ 1601 of_i2c_register_devices(adap); 1602 i2c_acpi_install_space_handler(adap); 1603 i2c_acpi_register_devices(adap); 1604 1605 if (adap->nr < __i2c_first_dynamic_bus_num) 1606 i2c_scan_static_board_info(adap); 1607 1608 /* Notify drivers */ 1609 mutex_lock(&core_lock); 1610 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); 1611 mutex_unlock(&core_lock); 1612 1613 return 0; 1614 1615 out_reg: 1616 init_completion(&adap->dev_released); 1617 device_unregister(&adap->dev); 1618 wait_for_completion(&adap->dev_released); 1619 out_list: 1620 mutex_lock(&core_lock); 1621 idr_remove(&i2c_adapter_idr, adap->nr); 1622 mutex_unlock(&core_lock); 1623 return res; 1624 } 1625 1626 /** 1627 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 1628 * @adap: the adapter to register (with adap->nr initialized) 1629 * Context: can sleep 1630 * 1631 * See i2c_add_numbered_adapter() for details. 1632 */ 1633 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) 1634 { 1635 int id; 1636 1637 mutex_lock(&core_lock); 1638 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); 1639 mutex_unlock(&core_lock); 1640 if (WARN(id < 0, "couldn't get idr")) 1641 return id == -ENOSPC ? -EBUSY : id; 1642 1643 return i2c_register_adapter(adap); 1644 } 1645 1646 /** 1647 * i2c_add_adapter - declare i2c adapter, use dynamic bus number 1648 * @adapter: the adapter to add 1649 * Context: can sleep 1650 * 1651 * This routine is used to declare an I2C adapter when its bus number 1652 * doesn't matter or when its bus number is specified by an dt alias. 1653 * Examples of bases when the bus number doesn't matter: I2C adapters 1654 * dynamically added by USB links or PCI plugin cards. 1655 * 1656 * When this returns zero, a new bus number was allocated and stored 1657 * in adap->nr, and the specified adapter became available for clients. 1658 * Otherwise, a negative errno value is returned. 1659 */ 1660 int i2c_add_adapter(struct i2c_adapter *adapter) 1661 { 1662 struct device *dev = &adapter->dev; 1663 int id; 1664 1665 if (dev->of_node) { 1666 id = of_alias_get_id(dev->of_node, "i2c"); 1667 if (id >= 0) { 1668 adapter->nr = id; 1669 return __i2c_add_numbered_adapter(adapter); 1670 } 1671 } 1672 1673 mutex_lock(&core_lock); 1674 id = idr_alloc(&i2c_adapter_idr, adapter, 1675 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); 1676 mutex_unlock(&core_lock); 1677 if (WARN(id < 0, "couldn't get idr")) 1678 return id; 1679 1680 adapter->nr = id; 1681 1682 return i2c_register_adapter(adapter); 1683 } 1684 EXPORT_SYMBOL(i2c_add_adapter); 1685 1686 /** 1687 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number 1688 * @adap: the adapter to register (with adap->nr initialized) 1689 * Context: can sleep 1690 * 1691 * This routine is used to declare an I2C adapter when its bus number 1692 * matters. For example, use it for I2C adapters from system-on-chip CPUs, 1693 * or otherwise built in to the system's mainboard, and where i2c_board_info 1694 * is used to properly configure I2C devices. 1695 * 1696 * If the requested bus number is set to -1, then this function will behave 1697 * identically to i2c_add_adapter, and will dynamically assign a bus number. 1698 * 1699 * If no devices have pre-been declared for this bus, then be sure to 1700 * register the adapter before any dynamically allocated ones. Otherwise 1701 * the required bus ID may not be available. 1702 * 1703 * When this returns zero, the specified adapter became available for 1704 * clients using the bus number provided in adap->nr. Also, the table 1705 * of I2C devices pre-declared using i2c_register_board_info() is scanned, 1706 * and the appropriate driver model device nodes are created. Otherwise, a 1707 * negative errno value is returned. 1708 */ 1709 int i2c_add_numbered_adapter(struct i2c_adapter *adap) 1710 { 1711 if (adap->nr == -1) /* -1 means dynamically assign bus id */ 1712 return i2c_add_adapter(adap); 1713 1714 return __i2c_add_numbered_adapter(adap); 1715 } 1716 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); 1717 1718 static void i2c_do_del_adapter(struct i2c_driver *driver, 1719 struct i2c_adapter *adapter) 1720 { 1721 struct i2c_client *client, *_n; 1722 1723 /* Remove the devices we created ourselves as the result of hardware 1724 * probing (using a driver's detect method) */ 1725 list_for_each_entry_safe(client, _n, &driver->clients, detected) { 1726 if (client->adapter == adapter) { 1727 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", 1728 client->name, client->addr); 1729 list_del(&client->detected); 1730 i2c_unregister_device(client); 1731 } 1732 } 1733 } 1734 1735 static int __unregister_client(struct device *dev, void *dummy) 1736 { 1737 struct i2c_client *client = i2c_verify_client(dev); 1738 if (client && strcmp(client->name, "dummy")) 1739 i2c_unregister_device(client); 1740 return 0; 1741 } 1742 1743 static int __unregister_dummy(struct device *dev, void *dummy) 1744 { 1745 struct i2c_client *client = i2c_verify_client(dev); 1746 i2c_unregister_device(client); 1747 return 0; 1748 } 1749 1750 static int __process_removed_adapter(struct device_driver *d, void *data) 1751 { 1752 i2c_do_del_adapter(to_i2c_driver(d), data); 1753 return 0; 1754 } 1755 1756 /** 1757 * i2c_del_adapter - unregister I2C adapter 1758 * @adap: the adapter being unregistered 1759 * Context: can sleep 1760 * 1761 * This unregisters an I2C adapter which was previously registered 1762 * by @i2c_add_adapter or @i2c_add_numbered_adapter. 1763 */ 1764 void i2c_del_adapter(struct i2c_adapter *adap) 1765 { 1766 struct i2c_adapter *found; 1767 struct i2c_client *client, *next; 1768 1769 /* First make sure that this adapter was ever added */ 1770 mutex_lock(&core_lock); 1771 found = idr_find(&i2c_adapter_idr, adap->nr); 1772 mutex_unlock(&core_lock); 1773 if (found != adap) { 1774 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); 1775 return; 1776 } 1777 1778 i2c_acpi_remove_space_handler(adap); 1779 /* Tell drivers about this removal */ 1780 mutex_lock(&core_lock); 1781 bus_for_each_drv(&i2c_bus_type, NULL, adap, 1782 __process_removed_adapter); 1783 mutex_unlock(&core_lock); 1784 1785 /* Remove devices instantiated from sysfs */ 1786 mutex_lock_nested(&adap->userspace_clients_lock, 1787 i2c_adapter_depth(adap)); 1788 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1789 detected) { 1790 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, 1791 client->addr); 1792 list_del(&client->detected); 1793 i2c_unregister_device(client); 1794 } 1795 mutex_unlock(&adap->userspace_clients_lock); 1796 1797 /* Detach any active clients. This can't fail, thus we do not 1798 * check the returned value. This is a two-pass process, because 1799 * we can't remove the dummy devices during the first pass: they 1800 * could have been instantiated by real devices wishing to clean 1801 * them up properly, so we give them a chance to do that first. */ 1802 device_for_each_child(&adap->dev, NULL, __unregister_client); 1803 device_for_each_child(&adap->dev, NULL, __unregister_dummy); 1804 1805 #ifdef CONFIG_I2C_COMPAT 1806 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, 1807 adap->dev.parent); 1808 #endif 1809 1810 /* device name is gone after device_unregister */ 1811 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); 1812 1813 pm_runtime_disable(&adap->dev); 1814 1815 i2c_host_notify_irq_teardown(adap); 1816 1817 /* wait until all references to the device are gone 1818 * 1819 * FIXME: This is old code and should ideally be replaced by an 1820 * alternative which results in decoupling the lifetime of the struct 1821 * device from the i2c_adapter, like spi or netdev do. Any solution 1822 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled! 1823 */ 1824 init_completion(&adap->dev_released); 1825 device_unregister(&adap->dev); 1826 wait_for_completion(&adap->dev_released); 1827 1828 /* free bus id */ 1829 mutex_lock(&core_lock); 1830 idr_remove(&i2c_adapter_idr, adap->nr); 1831 mutex_unlock(&core_lock); 1832 1833 /* Clear the device structure in case this adapter is ever going to be 1834 added again */ 1835 memset(&adap->dev, 0, sizeof(adap->dev)); 1836 } 1837 EXPORT_SYMBOL(i2c_del_adapter); 1838 1839 static void devm_i2c_del_adapter(void *adapter) 1840 { 1841 i2c_del_adapter(adapter); 1842 } 1843 1844 /** 1845 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter() 1846 * @dev: managing device for adding this I2C adapter 1847 * @adapter: the adapter to add 1848 * Context: can sleep 1849 * 1850 * Add adapter with dynamic bus number, same with i2c_add_adapter() 1851 * but the adapter will be auto deleted on driver detach. 1852 */ 1853 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter) 1854 { 1855 int ret; 1856 1857 ret = i2c_add_adapter(adapter); 1858 if (ret) 1859 return ret; 1860 1861 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter); 1862 } 1863 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter); 1864 1865 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p, 1866 u32 def_val, bool use_def) 1867 { 1868 int ret; 1869 1870 ret = device_property_read_u32(dev, prop_name, cur_val_p); 1871 if (ret && use_def) 1872 *cur_val_p = def_val; 1873 1874 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p); 1875 } 1876 1877 /** 1878 * i2c_parse_fw_timings - get I2C related timing parameters from firmware 1879 * @dev: The device to scan for I2C timing properties 1880 * @t: the i2c_timings struct to be filled with values 1881 * @use_defaults: bool to use sane defaults derived from the I2C specification 1882 * when properties are not found, otherwise don't update 1883 * 1884 * Scan the device for the generic I2C properties describing timing parameters 1885 * for the signal and fill the given struct with the results. If a property was 1886 * not found and use_defaults was true, then maximum timings are assumed which 1887 * are derived from the I2C specification. If use_defaults is not used, the 1888 * results will be as before, so drivers can apply their own defaults before 1889 * calling this helper. The latter is mainly intended for avoiding regressions 1890 * of existing drivers which want to switch to this function. New drivers 1891 * almost always should use the defaults. 1892 */ 1893 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) 1894 { 1895 bool u = use_defaults; 1896 u32 d; 1897 1898 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz, 1899 I2C_MAX_STANDARD_MODE_FREQ, u); 1900 1901 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 : 1902 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1903 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u); 1904 1905 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1906 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u); 1907 1908 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns", 1909 &t->scl_int_delay_ns, 0, u); 1910 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns, 1911 t->scl_fall_ns, u); 1912 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u); 1913 i2c_parse_timing(dev, "i2c-digital-filter-width-ns", 1914 &t->digital_filter_width_ns, 0, u); 1915 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency", 1916 &t->analog_filter_cutoff_freq_hz, 0, u); 1917 } 1918 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); 1919 1920 /* ------------------------------------------------------------------------- */ 1921 1922 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data)) 1923 { 1924 int res; 1925 1926 mutex_lock(&core_lock); 1927 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn); 1928 mutex_unlock(&core_lock); 1929 1930 return res; 1931 } 1932 EXPORT_SYMBOL_GPL(i2c_for_each_dev); 1933 1934 static int __process_new_driver(struct device *dev, void *data) 1935 { 1936 if (dev->type != &i2c_adapter_type) 1937 return 0; 1938 return i2c_do_add_adapter(data, to_i2c_adapter(dev)); 1939 } 1940 1941 /* 1942 * An i2c_driver is used with one or more i2c_client (device) nodes to access 1943 * i2c slave chips, on a bus instance associated with some i2c_adapter. 1944 */ 1945 1946 int i2c_register_driver(struct module *owner, struct i2c_driver *driver) 1947 { 1948 int res; 1949 1950 /* Can't register until after driver model init */ 1951 if (WARN_ON(!is_registered)) 1952 return -EAGAIN; 1953 1954 /* add the driver to the list of i2c drivers in the driver core */ 1955 driver->driver.owner = owner; 1956 driver->driver.bus = &i2c_bus_type; 1957 INIT_LIST_HEAD(&driver->clients); 1958 1959 /* When registration returns, the driver core 1960 * will have called probe() for all matching-but-unbound devices. 1961 */ 1962 res = driver_register(&driver->driver); 1963 if (res) 1964 return res; 1965 1966 pr_debug("driver [%s] registered\n", driver->driver.name); 1967 1968 /* Walk the adapters that are already present */ 1969 i2c_for_each_dev(driver, __process_new_driver); 1970 1971 return 0; 1972 } 1973 EXPORT_SYMBOL(i2c_register_driver); 1974 1975 static int __process_removed_driver(struct device *dev, void *data) 1976 { 1977 if (dev->type == &i2c_adapter_type) 1978 i2c_do_del_adapter(data, to_i2c_adapter(dev)); 1979 return 0; 1980 } 1981 1982 /** 1983 * i2c_del_driver - unregister I2C driver 1984 * @driver: the driver being unregistered 1985 * Context: can sleep 1986 */ 1987 void i2c_del_driver(struct i2c_driver *driver) 1988 { 1989 i2c_for_each_dev(driver, __process_removed_driver); 1990 1991 driver_unregister(&driver->driver); 1992 pr_debug("driver [%s] unregistered\n", driver->driver.name); 1993 } 1994 EXPORT_SYMBOL(i2c_del_driver); 1995 1996 /* ------------------------------------------------------------------------- */ 1997 1998 struct i2c_cmd_arg { 1999 unsigned cmd; 2000 void *arg; 2001 }; 2002 2003 static int i2c_cmd(struct device *dev, void *_arg) 2004 { 2005 struct i2c_client *client = i2c_verify_client(dev); 2006 struct i2c_cmd_arg *arg = _arg; 2007 struct i2c_driver *driver; 2008 2009 if (!client || !client->dev.driver) 2010 return 0; 2011 2012 driver = to_i2c_driver(client->dev.driver); 2013 if (driver->command) 2014 driver->command(client, arg->cmd, arg->arg); 2015 return 0; 2016 } 2017 2018 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) 2019 { 2020 struct i2c_cmd_arg cmd_arg; 2021 2022 cmd_arg.cmd = cmd; 2023 cmd_arg.arg = arg; 2024 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); 2025 } 2026 EXPORT_SYMBOL(i2c_clients_command); 2027 2028 static int __init i2c_init(void) 2029 { 2030 int retval; 2031 2032 retval = of_alias_get_highest_id("i2c"); 2033 2034 down_write(&__i2c_board_lock); 2035 if (retval >= __i2c_first_dynamic_bus_num) 2036 __i2c_first_dynamic_bus_num = retval + 1; 2037 up_write(&__i2c_board_lock); 2038 2039 retval = bus_register(&i2c_bus_type); 2040 if (retval) 2041 return retval; 2042 2043 is_registered = true; 2044 2045 #ifdef CONFIG_I2C_COMPAT 2046 i2c_adapter_compat_class = class_compat_register("i2c-adapter"); 2047 if (!i2c_adapter_compat_class) { 2048 retval = -ENOMEM; 2049 goto bus_err; 2050 } 2051 #endif 2052 retval = i2c_add_driver(&dummy_driver); 2053 if (retval) 2054 goto class_err; 2055 2056 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 2057 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); 2058 if (IS_ENABLED(CONFIG_ACPI)) 2059 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier)); 2060 2061 return 0; 2062 2063 class_err: 2064 #ifdef CONFIG_I2C_COMPAT 2065 class_compat_unregister(i2c_adapter_compat_class); 2066 bus_err: 2067 #endif 2068 is_registered = false; 2069 bus_unregister(&i2c_bus_type); 2070 return retval; 2071 } 2072 2073 static void __exit i2c_exit(void) 2074 { 2075 if (IS_ENABLED(CONFIG_ACPI)) 2076 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier)); 2077 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 2078 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier)); 2079 i2c_del_driver(&dummy_driver); 2080 #ifdef CONFIG_I2C_COMPAT 2081 class_compat_unregister(i2c_adapter_compat_class); 2082 #endif 2083 bus_unregister(&i2c_bus_type); 2084 tracepoint_synchronize_unregister(); 2085 } 2086 2087 /* We must initialize early, because some subsystems register i2c drivers 2088 * in subsys_initcall() code, but are linked (and initialized) before i2c. 2089 */ 2090 postcore_initcall(i2c_init); 2091 module_exit(i2c_exit); 2092 2093 /* ---------------------------------------------------- 2094 * the functional interface to the i2c busses. 2095 * ---------------------------------------------------- 2096 */ 2097 2098 /* Check if val is exceeding the quirk IFF quirk is non 0 */ 2099 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) 2100 2101 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) 2102 { 2103 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n", 2104 err_msg, msg->addr, msg->len, 2105 msg->flags & I2C_M_RD ? "read" : "write"); 2106 return -EOPNOTSUPP; 2107 } 2108 2109 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2110 { 2111 const struct i2c_adapter_quirks *q = adap->quirks; 2112 int max_num = q->max_num_msgs, i; 2113 bool do_len_check = true; 2114 2115 if (q->flags & I2C_AQ_COMB) { 2116 max_num = 2; 2117 2118 /* special checks for combined messages */ 2119 if (num == 2) { 2120 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD) 2121 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write"); 2122 2123 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD)) 2124 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read"); 2125 2126 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr) 2127 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr"); 2128 2129 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len)) 2130 return i2c_quirk_error(adap, &msgs[0], "msg too long"); 2131 2132 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len)) 2133 return i2c_quirk_error(adap, &msgs[1], "msg too long"); 2134 2135 do_len_check = false; 2136 } 2137 } 2138 2139 if (i2c_quirk_exceeded(num, max_num)) 2140 return i2c_quirk_error(adap, &msgs[0], "too many messages"); 2141 2142 for (i = 0; i < num; i++) { 2143 u16 len = msgs[i].len; 2144 2145 if (msgs[i].flags & I2C_M_RD) { 2146 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len)) 2147 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2148 2149 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0) 2150 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2151 } else { 2152 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len)) 2153 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2154 2155 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0) 2156 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2157 } 2158 } 2159 2160 return 0; 2161 } 2162 2163 /** 2164 * __i2c_transfer - unlocked flavor of i2c_transfer 2165 * @adap: Handle to I2C bus 2166 * @msgs: One or more messages to execute before STOP is issued to 2167 * terminate the operation; each message begins with a START. 2168 * @num: Number of messages to be executed. 2169 * 2170 * Returns negative errno, else the number of messages executed. 2171 * 2172 * Adapter lock must be held when calling this function. No debug logging 2173 * takes place. adap->algo->master_xfer existence isn't checked. 2174 */ 2175 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2176 { 2177 unsigned long orig_jiffies; 2178 int ret, try; 2179 2180 if (WARN_ON(!msgs || num < 1)) 2181 return -EINVAL; 2182 2183 ret = __i2c_check_suspended(adap); 2184 if (ret) 2185 return ret; 2186 2187 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) 2188 return -EOPNOTSUPP; 2189 2190 /* 2191 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets 2192 * enabled. This is an efficient way of keeping the for-loop from 2193 * being executed when not needed. 2194 */ 2195 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2196 int i; 2197 for (i = 0; i < num; i++) 2198 if (msgs[i].flags & I2C_M_RD) 2199 trace_i2c_read(adap, &msgs[i], i); 2200 else 2201 trace_i2c_write(adap, &msgs[i], i); 2202 } 2203 2204 /* Retry automatically on arbitration loss */ 2205 orig_jiffies = jiffies; 2206 for (ret = 0, try = 0; try <= adap->retries; try++) { 2207 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic) 2208 ret = adap->algo->master_xfer_atomic(adap, msgs, num); 2209 else 2210 ret = adap->algo->master_xfer(adap, msgs, num); 2211 2212 if (ret != -EAGAIN) 2213 break; 2214 if (time_after(jiffies, orig_jiffies + adap->timeout)) 2215 break; 2216 } 2217 2218 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2219 int i; 2220 for (i = 0; i < ret; i++) 2221 if (msgs[i].flags & I2C_M_RD) 2222 trace_i2c_reply(adap, &msgs[i], i); 2223 trace_i2c_result(adap, num, ret); 2224 } 2225 2226 return ret; 2227 } 2228 EXPORT_SYMBOL(__i2c_transfer); 2229 2230 /** 2231 * i2c_transfer - execute a single or combined I2C message 2232 * @adap: Handle to I2C bus 2233 * @msgs: One or more messages to execute before STOP is issued to 2234 * terminate the operation; each message begins with a START. 2235 * @num: Number of messages to be executed. 2236 * 2237 * Returns negative errno, else the number of messages executed. 2238 * 2239 * Note that there is no requirement that each message be sent to 2240 * the same slave address, although that is the most common model. 2241 */ 2242 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2243 { 2244 int ret; 2245 2246 if (!adap->algo->master_xfer) { 2247 dev_dbg(&adap->dev, "I2C level transfers not supported\n"); 2248 return -EOPNOTSUPP; 2249 } 2250 2251 /* REVISIT the fault reporting model here is weak: 2252 * 2253 * - When we get an error after receiving N bytes from a slave, 2254 * there is no way to report "N". 2255 * 2256 * - When we get a NAK after transmitting N bytes to a slave, 2257 * there is no way to report "N" ... or to let the master 2258 * continue executing the rest of this combined message, if 2259 * that's the appropriate response. 2260 * 2261 * - When for example "num" is two and we successfully complete 2262 * the first message but get an error part way through the 2263 * second, it's unclear whether that should be reported as 2264 * one (discarding status on the second message) or errno 2265 * (discarding status on the first one). 2266 */ 2267 ret = __i2c_lock_bus_helper(adap); 2268 if (ret) 2269 return ret; 2270 2271 ret = __i2c_transfer(adap, msgs, num); 2272 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); 2273 2274 return ret; 2275 } 2276 EXPORT_SYMBOL(i2c_transfer); 2277 2278 /** 2279 * i2c_transfer_buffer_flags - issue a single I2C message transferring data 2280 * to/from a buffer 2281 * @client: Handle to slave device 2282 * @buf: Where the data is stored 2283 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16 2284 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads 2285 * 2286 * Returns negative errno, or else the number of bytes transferred. 2287 */ 2288 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf, 2289 int count, u16 flags) 2290 { 2291 int ret; 2292 struct i2c_msg msg = { 2293 .addr = client->addr, 2294 .flags = flags | (client->flags & I2C_M_TEN), 2295 .len = count, 2296 .buf = buf, 2297 }; 2298 2299 ret = i2c_transfer(client->adapter, &msg, 1); 2300 2301 /* 2302 * If everything went ok (i.e. 1 msg transferred), return #bytes 2303 * transferred, else error code. 2304 */ 2305 return (ret == 1) ? count : ret; 2306 } 2307 EXPORT_SYMBOL(i2c_transfer_buffer_flags); 2308 2309 /** 2310 * i2c_get_device_id - get manufacturer, part id and die revision of a device 2311 * @client: The device to query 2312 * @id: The queried information 2313 * 2314 * Returns negative errno on error, zero on success. 2315 */ 2316 int i2c_get_device_id(const struct i2c_client *client, 2317 struct i2c_device_identity *id) 2318 { 2319 struct i2c_adapter *adap = client->adapter; 2320 union i2c_smbus_data raw_id; 2321 int ret; 2322 2323 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) 2324 return -EOPNOTSUPP; 2325 2326 raw_id.block[0] = 3; 2327 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0, 2328 I2C_SMBUS_READ, client->addr << 1, 2329 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id); 2330 if (ret) 2331 return ret; 2332 2333 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4); 2334 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3); 2335 id->die_revision = raw_id.block[3] & 0x7; 2336 return 0; 2337 } 2338 EXPORT_SYMBOL_GPL(i2c_get_device_id); 2339 2340 /* ---------------------------------------------------- 2341 * the i2c address scanning function 2342 * Will not work for 10-bit addresses! 2343 * ---------------------------------------------------- 2344 */ 2345 2346 /* 2347 * Legacy default probe function, mostly relevant for SMBus. The default 2348 * probe method is a quick write, but it is known to corrupt the 24RF08 2349 * EEPROMs due to a state machine bug, and could also irreversibly 2350 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f, 2351 * we use a short byte read instead. Also, some bus drivers don't implement 2352 * quick write, so we fallback to a byte read in that case too. 2353 * On x86, there is another special case for FSC hardware monitoring chips, 2354 * which want regular byte reads (address 0x73.) Fortunately, these are the 2355 * only known chips using this I2C address on PC hardware. 2356 * Returns 1 if probe succeeded, 0 if not. 2357 */ 2358 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) 2359 { 2360 int err; 2361 union i2c_smbus_data dummy; 2362 2363 #ifdef CONFIG_X86 2364 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON) 2365 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA)) 2366 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2367 I2C_SMBUS_BYTE_DATA, &dummy); 2368 else 2369 #endif 2370 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) 2371 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) 2372 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, 2373 I2C_SMBUS_QUICK, NULL); 2374 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) 2375 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2376 I2C_SMBUS_BYTE, &dummy); 2377 else { 2378 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n", 2379 addr); 2380 err = -EOPNOTSUPP; 2381 } 2382 2383 return err >= 0; 2384 } 2385 2386 static int i2c_detect_address(struct i2c_client *temp_client, 2387 struct i2c_driver *driver) 2388 { 2389 struct i2c_board_info info; 2390 struct i2c_adapter *adapter = temp_client->adapter; 2391 int addr = temp_client->addr; 2392 int err; 2393 2394 /* Make sure the address is valid */ 2395 err = i2c_check_7bit_addr_validity_strict(addr); 2396 if (err) { 2397 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n", 2398 addr); 2399 return err; 2400 } 2401 2402 /* Skip if already in use (7 bit, no need to encode flags) */ 2403 if (i2c_check_addr_busy(adapter, addr)) 2404 return 0; 2405 2406 /* Make sure there is something at this address */ 2407 if (!i2c_default_probe(adapter, addr)) 2408 return 0; 2409 2410 /* Finally call the custom detection function */ 2411 memset(&info, 0, sizeof(struct i2c_board_info)); 2412 info.addr = addr; 2413 err = driver->detect(temp_client, &info); 2414 if (err) { 2415 /* -ENODEV is returned if the detection fails. We catch it 2416 here as this isn't an error. */ 2417 return err == -ENODEV ? 0 : err; 2418 } 2419 2420 /* Consistency check */ 2421 if (info.type[0] == '\0') { 2422 dev_err(&adapter->dev, 2423 "%s detection function provided no name for 0x%x\n", 2424 driver->driver.name, addr); 2425 } else { 2426 struct i2c_client *client; 2427 2428 /* Detection succeeded, instantiate the device */ 2429 if (adapter->class & I2C_CLASS_DEPRECATED) 2430 dev_warn(&adapter->dev, 2431 "This adapter will soon drop class based instantiation of devices. " 2432 "Please make sure client 0x%02x gets instantiated by other means. " 2433 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n", 2434 info.addr); 2435 2436 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n", 2437 info.type, info.addr); 2438 client = i2c_new_client_device(adapter, &info); 2439 if (!IS_ERR(client)) 2440 list_add_tail(&client->detected, &driver->clients); 2441 else 2442 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n", 2443 info.type, info.addr); 2444 } 2445 return 0; 2446 } 2447 2448 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) 2449 { 2450 const unsigned short *address_list; 2451 struct i2c_client *temp_client; 2452 int i, err = 0; 2453 2454 address_list = driver->address_list; 2455 if (!driver->detect || !address_list) 2456 return 0; 2457 2458 /* Warn that the adapter lost class based instantiation */ 2459 if (adapter->class == I2C_CLASS_DEPRECATED) { 2460 dev_dbg(&adapter->dev, 2461 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. " 2462 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n", 2463 driver->driver.name); 2464 return 0; 2465 } 2466 2467 /* Stop here if the classes do not match */ 2468 if (!(adapter->class & driver->class)) 2469 return 0; 2470 2471 /* Set up a temporary client to help detect callback */ 2472 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); 2473 if (!temp_client) 2474 return -ENOMEM; 2475 temp_client->adapter = adapter; 2476 2477 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { 2478 dev_dbg(&adapter->dev, 2479 "found normal entry for adapter %d, addr 0x%02x\n", 2480 i2c_adapter_id(adapter), address_list[i]); 2481 temp_client->addr = address_list[i]; 2482 err = i2c_detect_address(temp_client, driver); 2483 if (unlikely(err)) 2484 break; 2485 } 2486 2487 kfree(temp_client); 2488 return err; 2489 } 2490 2491 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) 2492 { 2493 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2494 I2C_SMBUS_QUICK, NULL) >= 0; 2495 } 2496 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); 2497 2498 struct i2c_client * 2499 i2c_new_scanned_device(struct i2c_adapter *adap, 2500 struct i2c_board_info *info, 2501 unsigned short const *addr_list, 2502 int (*probe)(struct i2c_adapter *adap, unsigned short addr)) 2503 { 2504 int i; 2505 2506 if (!probe) 2507 probe = i2c_default_probe; 2508 2509 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { 2510 /* Check address validity */ 2511 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) { 2512 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n", 2513 addr_list[i]); 2514 continue; 2515 } 2516 2517 /* Check address availability (7 bit, no need to encode flags) */ 2518 if (i2c_check_addr_busy(adap, addr_list[i])) { 2519 dev_dbg(&adap->dev, 2520 "Address 0x%02x already in use, not probing\n", 2521 addr_list[i]); 2522 continue; 2523 } 2524 2525 /* Test address responsiveness */ 2526 if (probe(adap, addr_list[i])) 2527 break; 2528 } 2529 2530 if (addr_list[i] == I2C_CLIENT_END) { 2531 dev_dbg(&adap->dev, "Probing failed, no device found\n"); 2532 return ERR_PTR(-ENODEV); 2533 } 2534 2535 info->addr = addr_list[i]; 2536 return i2c_new_client_device(adap, info); 2537 } 2538 EXPORT_SYMBOL_GPL(i2c_new_scanned_device); 2539 2540 struct i2c_adapter *i2c_get_adapter(int nr) 2541 { 2542 struct i2c_adapter *adapter; 2543 2544 mutex_lock(&core_lock); 2545 adapter = idr_find(&i2c_adapter_idr, nr); 2546 if (!adapter) 2547 goto exit; 2548 2549 if (try_module_get(adapter->owner)) 2550 get_device(&adapter->dev); 2551 else 2552 adapter = NULL; 2553 2554 exit: 2555 mutex_unlock(&core_lock); 2556 return adapter; 2557 } 2558 EXPORT_SYMBOL(i2c_get_adapter); 2559 2560 void i2c_put_adapter(struct i2c_adapter *adap) 2561 { 2562 if (!adap) 2563 return; 2564 2565 put_device(&adap->dev); 2566 module_put(adap->owner); 2567 } 2568 EXPORT_SYMBOL(i2c_put_adapter); 2569 2570 /** 2571 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg 2572 * @msg: the message to be checked 2573 * @threshold: the minimum number of bytes for which using DMA makes sense. 2574 * Should at least be 1. 2575 * 2576 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO. 2577 * Or a valid pointer to be used with DMA. After use, release it by 2578 * calling i2c_put_dma_safe_msg_buf(). 2579 * 2580 * This function must only be called from process context! 2581 */ 2582 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold) 2583 { 2584 /* also skip 0-length msgs for bogus thresholds of 0 */ 2585 if (!threshold) 2586 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n", 2587 msg->addr); 2588 if (msg->len < threshold || msg->len == 0) 2589 return NULL; 2590 2591 if (msg->flags & I2C_M_DMA_SAFE) 2592 return msg->buf; 2593 2594 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n", 2595 msg->addr, msg->len); 2596 2597 if (msg->flags & I2C_M_RD) 2598 return kzalloc(msg->len, GFP_KERNEL); 2599 else 2600 return kmemdup(msg->buf, msg->len, GFP_KERNEL); 2601 } 2602 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf); 2603 2604 /** 2605 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg 2606 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL. 2607 * @msg: the message which the buffer corresponds to 2608 * @xferred: bool saying if the message was transferred 2609 */ 2610 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred) 2611 { 2612 if (!buf || buf == msg->buf) 2613 return; 2614 2615 if (xferred && msg->flags & I2C_M_RD) 2616 memcpy(msg->buf, buf, msg->len); 2617 2618 kfree(buf); 2619 } 2620 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf); 2621 2622 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 2623 MODULE_DESCRIPTION("I2C-Bus main module"); 2624 MODULE_LICENSE("GPL"); 2625