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_driver *driver; 470 int status; 471 472 if (!client) 473 return 0; 474 475 client->irq = client->init_irq; 476 477 if (!client->irq) { 478 int irq = -ENOENT; 479 480 if (client->flags & I2C_CLIENT_HOST_NOTIFY) { 481 dev_dbg(dev, "Using Host Notify IRQ\n"); 482 /* Keep adapter active when Host Notify is required */ 483 pm_runtime_get_sync(&client->adapter->dev); 484 irq = i2c_smbus_host_notify_to_irq(client); 485 } else if (dev->of_node) { 486 irq = of_irq_get_byname(dev->of_node, "irq"); 487 if (irq == -EINVAL || irq == -ENODATA) 488 irq = of_irq_get(dev->of_node, 0); 489 } else if (ACPI_COMPANION(dev)) { 490 irq = i2c_acpi_get_irq(client); 491 } 492 if (irq == -EPROBE_DEFER) { 493 status = irq; 494 goto put_sync_adapter; 495 } 496 497 if (irq < 0) 498 irq = 0; 499 500 client->irq = irq; 501 } 502 503 driver = to_i2c_driver(dev->driver); 504 505 /* 506 * An I2C ID table is not mandatory, if and only if, a suitable OF 507 * or ACPI ID table is supplied for the probing device. 508 */ 509 if (!driver->id_table && 510 !acpi_driver_match_device(dev, dev->driver) && 511 !i2c_of_match_device(dev->driver->of_match_table, client)) { 512 status = -ENODEV; 513 goto put_sync_adapter; 514 } 515 516 if (client->flags & I2C_CLIENT_WAKE) { 517 int wakeirq; 518 519 wakeirq = of_irq_get_byname(dev->of_node, "wakeup"); 520 if (wakeirq == -EPROBE_DEFER) { 521 status = wakeirq; 522 goto put_sync_adapter; 523 } 524 525 device_init_wakeup(&client->dev, true); 526 527 if (wakeirq > 0 && wakeirq != client->irq) 528 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq); 529 else if (client->irq > 0) 530 status = dev_pm_set_wake_irq(dev, client->irq); 531 else 532 status = 0; 533 534 if (status) 535 dev_warn(&client->dev, "failed to set up wakeup irq\n"); 536 } 537 538 dev_dbg(dev, "probe\n"); 539 540 status = of_clk_set_defaults(dev->of_node, false); 541 if (status < 0) 542 goto err_clear_wakeup_irq; 543 544 status = dev_pm_domain_attach(&client->dev, 545 !i2c_acpi_waive_d0_probe(dev)); 546 if (status) 547 goto err_clear_wakeup_irq; 548 549 client->devres_group_id = devres_open_group(&client->dev, NULL, 550 GFP_KERNEL); 551 if (!client->devres_group_id) { 552 status = -ENOMEM; 553 goto err_detach_pm_domain; 554 } 555 556 /* 557 * When there are no more users of probe(), 558 * rename probe_new to probe. 559 */ 560 if (driver->probe_new) 561 status = driver->probe_new(client); 562 else if (driver->probe) 563 status = driver->probe(client, 564 i2c_match_id(driver->id_table, client)); 565 else 566 status = -EINVAL; 567 568 /* 569 * Note that we are not closing the devres group opened above so 570 * even resources that were attached to the device after probe is 571 * run are released when i2c_device_remove() is executed. This is 572 * needed as some drivers would allocate additional resources, 573 * for example when updating firmware. 574 */ 575 576 if (status) 577 goto err_release_driver_resources; 578 579 return 0; 580 581 err_release_driver_resources: 582 devres_release_group(&client->dev, client->devres_group_id); 583 err_detach_pm_domain: 584 dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev)); 585 err_clear_wakeup_irq: 586 dev_pm_clear_wake_irq(&client->dev); 587 device_init_wakeup(&client->dev, false); 588 put_sync_adapter: 589 if (client->flags & I2C_CLIENT_HOST_NOTIFY) 590 pm_runtime_put_sync(&client->adapter->dev); 591 592 return status; 593 } 594 595 static void i2c_device_remove(struct device *dev) 596 { 597 struct i2c_client *client = to_i2c_client(dev); 598 struct i2c_driver *driver; 599 600 driver = to_i2c_driver(dev->driver); 601 if (driver->remove) { 602 int status; 603 604 dev_dbg(dev, "remove\n"); 605 606 status = driver->remove(client); 607 if (status) 608 dev_warn(dev, "remove failed (%pe), will be ignored\n", ERR_PTR(status)); 609 } 610 611 devres_release_group(&client->dev, client->devres_group_id); 612 613 dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev)); 614 615 dev_pm_clear_wake_irq(&client->dev); 616 device_init_wakeup(&client->dev, false); 617 618 client->irq = 0; 619 if (client->flags & I2C_CLIENT_HOST_NOTIFY) 620 pm_runtime_put(&client->adapter->dev); 621 } 622 623 static void i2c_device_shutdown(struct device *dev) 624 { 625 struct i2c_client *client = i2c_verify_client(dev); 626 struct i2c_driver *driver; 627 628 if (!client || !dev->driver) 629 return; 630 driver = to_i2c_driver(dev->driver); 631 if (driver->shutdown) 632 driver->shutdown(client); 633 else if (client->irq > 0) 634 disable_irq(client->irq); 635 } 636 637 static void i2c_client_dev_release(struct device *dev) 638 { 639 kfree(to_i2c_client(dev)); 640 } 641 642 static ssize_t 643 name_show(struct device *dev, struct device_attribute *attr, char *buf) 644 { 645 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? 646 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); 647 } 648 static DEVICE_ATTR_RO(name); 649 650 static ssize_t 651 modalias_show(struct device *dev, struct device_attribute *attr, char *buf) 652 { 653 struct i2c_client *client = to_i2c_client(dev); 654 int len; 655 656 len = of_device_modalias(dev, buf, PAGE_SIZE); 657 if (len != -ENODEV) 658 return len; 659 660 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); 661 if (len != -ENODEV) 662 return len; 663 664 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); 665 } 666 static DEVICE_ATTR_RO(modalias); 667 668 static struct attribute *i2c_dev_attrs[] = { 669 &dev_attr_name.attr, 670 /* modalias helps coldplug: modprobe $(cat .../modalias) */ 671 &dev_attr_modalias.attr, 672 NULL 673 }; 674 ATTRIBUTE_GROUPS(i2c_dev); 675 676 struct bus_type i2c_bus_type = { 677 .name = "i2c", 678 .match = i2c_device_match, 679 .probe = i2c_device_probe, 680 .remove = i2c_device_remove, 681 .shutdown = i2c_device_shutdown, 682 }; 683 EXPORT_SYMBOL_GPL(i2c_bus_type); 684 685 struct device_type i2c_client_type = { 686 .groups = i2c_dev_groups, 687 .uevent = i2c_device_uevent, 688 .release = i2c_client_dev_release, 689 }; 690 EXPORT_SYMBOL_GPL(i2c_client_type); 691 692 693 /** 694 * i2c_verify_client - return parameter as i2c_client, or NULL 695 * @dev: device, probably from some driver model iterator 696 * 697 * When traversing the driver model tree, perhaps using driver model 698 * iterators like @device_for_each_child(), you can't assume very much 699 * about the nodes you find. Use this function to avoid oopses caused 700 * by wrongly treating some non-I2C device as an i2c_client. 701 */ 702 struct i2c_client *i2c_verify_client(struct device *dev) 703 { 704 return (dev->type == &i2c_client_type) 705 ? to_i2c_client(dev) 706 : NULL; 707 } 708 EXPORT_SYMBOL(i2c_verify_client); 709 710 711 /* Return a unique address which takes the flags of the client into account */ 712 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client) 713 { 714 unsigned short addr = client->addr; 715 716 /* For some client flags, add an arbitrary offset to avoid collisions */ 717 if (client->flags & I2C_CLIENT_TEN) 718 addr |= I2C_ADDR_OFFSET_TEN_BIT; 719 720 if (client->flags & I2C_CLIENT_SLAVE) 721 addr |= I2C_ADDR_OFFSET_SLAVE; 722 723 return addr; 724 } 725 726 /* This is a permissive address validity check, I2C address map constraints 727 * are purposely not enforced, except for the general call address. */ 728 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags) 729 { 730 if (flags & I2C_CLIENT_TEN) { 731 /* 10-bit address, all values are valid */ 732 if (addr > 0x3ff) 733 return -EINVAL; 734 } else { 735 /* 7-bit address, reject the general call address */ 736 if (addr == 0x00 || addr > 0x7f) 737 return -EINVAL; 738 } 739 return 0; 740 } 741 742 /* And this is a strict address validity check, used when probing. If a 743 * device uses a reserved address, then it shouldn't be probed. 7-bit 744 * addressing is assumed, 10-bit address devices are rare and should be 745 * explicitly enumerated. */ 746 int i2c_check_7bit_addr_validity_strict(unsigned short addr) 747 { 748 /* 749 * Reserved addresses per I2C specification: 750 * 0x00 General call address / START byte 751 * 0x01 CBUS address 752 * 0x02 Reserved for different bus format 753 * 0x03 Reserved for future purposes 754 * 0x04-0x07 Hs-mode master code 755 * 0x78-0x7b 10-bit slave addressing 756 * 0x7c-0x7f Reserved for future purposes 757 */ 758 if (addr < 0x08 || addr > 0x77) 759 return -EINVAL; 760 return 0; 761 } 762 763 static int __i2c_check_addr_busy(struct device *dev, void *addrp) 764 { 765 struct i2c_client *client = i2c_verify_client(dev); 766 int addr = *(int *)addrp; 767 768 if (client && i2c_encode_flags_to_addr(client) == addr) 769 return -EBUSY; 770 return 0; 771 } 772 773 /* walk up mux tree */ 774 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) 775 { 776 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 777 int result; 778 779 result = device_for_each_child(&adapter->dev, &addr, 780 __i2c_check_addr_busy); 781 782 if (!result && parent) 783 result = i2c_check_mux_parents(parent, addr); 784 785 return result; 786 } 787 788 /* recurse down mux tree */ 789 static int i2c_check_mux_children(struct device *dev, void *addrp) 790 { 791 int result; 792 793 if (dev->type == &i2c_adapter_type) 794 result = device_for_each_child(dev, addrp, 795 i2c_check_mux_children); 796 else 797 result = __i2c_check_addr_busy(dev, addrp); 798 799 return result; 800 } 801 802 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) 803 { 804 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 805 int result = 0; 806 807 if (parent) 808 result = i2c_check_mux_parents(parent, addr); 809 810 if (!result) 811 result = device_for_each_child(&adapter->dev, &addr, 812 i2c_check_mux_children); 813 814 return result; 815 } 816 817 /** 818 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment 819 * @adapter: Target I2C bus segment 820 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT 821 * locks only this branch in the adapter tree 822 */ 823 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, 824 unsigned int flags) 825 { 826 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); 827 } 828 829 /** 830 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment 831 * @adapter: Target I2C bus segment 832 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT 833 * trylocks only this branch in the adapter tree 834 */ 835 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, 836 unsigned int flags) 837 { 838 return rt_mutex_trylock(&adapter->bus_lock); 839 } 840 841 /** 842 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment 843 * @adapter: Target I2C bus segment 844 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT 845 * unlocks only this branch in the adapter tree 846 */ 847 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, 848 unsigned int flags) 849 { 850 rt_mutex_unlock(&adapter->bus_lock); 851 } 852 853 static void i2c_dev_set_name(struct i2c_adapter *adap, 854 struct i2c_client *client, 855 struct i2c_board_info const *info) 856 { 857 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 858 859 if (info && info->dev_name) { 860 dev_set_name(&client->dev, "i2c-%s", info->dev_name); 861 return; 862 } 863 864 if (adev) { 865 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev)); 866 return; 867 } 868 869 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), 870 i2c_encode_flags_to_addr(client)); 871 } 872 873 int i2c_dev_irq_from_resources(const struct resource *resources, 874 unsigned int num_resources) 875 { 876 struct irq_data *irqd; 877 int i; 878 879 for (i = 0; i < num_resources; i++) { 880 const struct resource *r = &resources[i]; 881 882 if (resource_type(r) != IORESOURCE_IRQ) 883 continue; 884 885 if (r->flags & IORESOURCE_BITS) { 886 irqd = irq_get_irq_data(r->start); 887 if (!irqd) 888 break; 889 890 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); 891 } 892 893 return r->start; 894 } 895 896 return 0; 897 } 898 899 /** 900 * i2c_new_client_device - instantiate an i2c device 901 * @adap: the adapter managing the device 902 * @info: describes one I2C device; bus_num is ignored 903 * Context: can sleep 904 * 905 * Create an i2c device. Binding is handled through driver model 906 * probe()/remove() methods. A driver may be bound to this device when we 907 * return from this function, or any later moment (e.g. maybe hotplugging will 908 * load the driver module). This call is not appropriate for use by mainboard 909 * initialization logic, which usually runs during an arch_initcall() long 910 * before any i2c_adapter could exist. 911 * 912 * This returns the new i2c client, which may be saved for later use with 913 * i2c_unregister_device(); or an ERR_PTR to describe the error. 914 */ 915 struct i2c_client * 916 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info) 917 { 918 struct i2c_client *client; 919 int status; 920 921 client = kzalloc(sizeof *client, GFP_KERNEL); 922 if (!client) 923 return ERR_PTR(-ENOMEM); 924 925 client->adapter = adap; 926 927 client->dev.platform_data = info->platform_data; 928 client->flags = info->flags; 929 client->addr = info->addr; 930 931 client->init_irq = info->irq; 932 if (!client->init_irq) 933 client->init_irq = i2c_dev_irq_from_resources(info->resources, 934 info->num_resources); 935 936 strscpy(client->name, info->type, sizeof(client->name)); 937 938 status = i2c_check_addr_validity(client->addr, client->flags); 939 if (status) { 940 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", 941 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); 942 goto out_err_silent; 943 } 944 945 /* Check for address business */ 946 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); 947 if (status) 948 goto out_err; 949 950 client->dev.parent = &client->adapter->dev; 951 client->dev.bus = &i2c_bus_type; 952 client->dev.type = &i2c_client_type; 953 client->dev.of_node = of_node_get(info->of_node); 954 client->dev.fwnode = info->fwnode; 955 956 device_enable_async_suspend(&client->dev); 957 i2c_dev_set_name(adap, client, info); 958 959 if (info->swnode) { 960 status = device_add_software_node(&client->dev, info->swnode); 961 if (status) { 962 dev_err(&adap->dev, 963 "Failed to add software node to client %s: %d\n", 964 client->name, status); 965 goto out_err_put_of_node; 966 } 967 } 968 969 status = device_register(&client->dev); 970 if (status) 971 goto out_remove_swnode; 972 973 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", 974 client->name, dev_name(&client->dev)); 975 976 return client; 977 978 out_remove_swnode: 979 device_remove_software_node(&client->dev); 980 out_err_put_of_node: 981 of_node_put(info->of_node); 982 out_err: 983 dev_err(&adap->dev, 984 "Failed to register i2c client %s at 0x%02x (%d)\n", 985 client->name, client->addr, status); 986 out_err_silent: 987 kfree(client); 988 return ERR_PTR(status); 989 } 990 EXPORT_SYMBOL_GPL(i2c_new_client_device); 991 992 /** 993 * i2c_unregister_device - reverse effect of i2c_new_*_device() 994 * @client: value returned from i2c_new_*_device() 995 * Context: can sleep 996 */ 997 void i2c_unregister_device(struct i2c_client *client) 998 { 999 if (IS_ERR_OR_NULL(client)) 1000 return; 1001 1002 if (client->dev.of_node) { 1003 of_node_clear_flag(client->dev.of_node, OF_POPULATED); 1004 of_node_put(client->dev.of_node); 1005 } 1006 1007 if (ACPI_COMPANION(&client->dev)) 1008 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev)); 1009 device_remove_software_node(&client->dev); 1010 device_unregister(&client->dev); 1011 } 1012 EXPORT_SYMBOL_GPL(i2c_unregister_device); 1013 1014 1015 static const struct i2c_device_id dummy_id[] = { 1016 { "dummy", 0 }, 1017 { }, 1018 }; 1019 1020 static int dummy_probe(struct i2c_client *client, 1021 const struct i2c_device_id *id) 1022 { 1023 return 0; 1024 } 1025 1026 static struct i2c_driver dummy_driver = { 1027 .driver.name = "dummy", 1028 .probe = dummy_probe, 1029 .id_table = dummy_id, 1030 }; 1031 1032 /** 1033 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1034 * @adapter: the adapter managing the device 1035 * @address: seven bit address to be used 1036 * Context: can sleep 1037 * 1038 * This returns an I2C client bound to the "dummy" driver, intended for use 1039 * with devices that consume multiple addresses. Examples of such chips 1040 * include various EEPROMS (like 24c04 and 24c08 models). 1041 * 1042 * These dummy devices have two main uses. First, most I2C and SMBus calls 1043 * except i2c_transfer() need a client handle; the dummy will be that handle. 1044 * And second, this prevents the specified address from being bound to a 1045 * different driver. 1046 * 1047 * This returns the new i2c client, which should be saved for later use with 1048 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1049 */ 1050 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address) 1051 { 1052 struct i2c_board_info info = { 1053 I2C_BOARD_INFO("dummy", address), 1054 }; 1055 1056 return i2c_new_client_device(adapter, &info); 1057 } 1058 EXPORT_SYMBOL_GPL(i2c_new_dummy_device); 1059 1060 static void devm_i2c_release_dummy(void *client) 1061 { 1062 i2c_unregister_device(client); 1063 } 1064 1065 /** 1066 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1067 * @dev: device the managed resource is bound to 1068 * @adapter: the adapter managing the device 1069 * @address: seven bit address to be used 1070 * Context: can sleep 1071 * 1072 * This is the device-managed version of @i2c_new_dummy_device. It returns the 1073 * new i2c client or an ERR_PTR in case of an error. 1074 */ 1075 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev, 1076 struct i2c_adapter *adapter, 1077 u16 address) 1078 { 1079 struct i2c_client *client; 1080 int ret; 1081 1082 client = i2c_new_dummy_device(adapter, address); 1083 if (IS_ERR(client)) 1084 return client; 1085 1086 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client); 1087 if (ret) 1088 return ERR_PTR(ret); 1089 1090 return client; 1091 } 1092 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device); 1093 1094 /** 1095 * i2c_new_ancillary_device - Helper to get the instantiated secondary address 1096 * and create the associated device 1097 * @client: Handle to the primary client 1098 * @name: Handle to specify which secondary address to get 1099 * @default_addr: Used as a fallback if no secondary address was specified 1100 * Context: can sleep 1101 * 1102 * I2C clients can be composed of multiple I2C slaves bound together in a single 1103 * component. The I2C client driver then binds to the master I2C slave and needs 1104 * to create I2C dummy clients to communicate with all the other slaves. 1105 * 1106 * This function creates and returns an I2C dummy client whose I2C address is 1107 * retrieved from the platform firmware based on the given slave name. If no 1108 * address is specified by the firmware default_addr is used. 1109 * 1110 * On DT-based platforms the address is retrieved from the "reg" property entry 1111 * cell whose "reg-names" value matches the slave name. 1112 * 1113 * This returns the new i2c client, which should be saved for later use with 1114 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1115 */ 1116 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, 1117 const char *name, 1118 u16 default_addr) 1119 { 1120 struct device_node *np = client->dev.of_node; 1121 u32 addr = default_addr; 1122 int i; 1123 1124 if (np) { 1125 i = of_property_match_string(np, "reg-names", name); 1126 if (i >= 0) 1127 of_property_read_u32_index(np, "reg", i, &addr); 1128 } 1129 1130 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); 1131 return i2c_new_dummy_device(client->adapter, addr); 1132 } 1133 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device); 1134 1135 /* ------------------------------------------------------------------------- */ 1136 1137 /* I2C bus adapters -- one roots each I2C or SMBUS segment */ 1138 1139 static void i2c_adapter_dev_release(struct device *dev) 1140 { 1141 struct i2c_adapter *adap = to_i2c_adapter(dev); 1142 complete(&adap->dev_released); 1143 } 1144 1145 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) 1146 { 1147 unsigned int depth = 0; 1148 1149 while ((adapter = i2c_parent_is_i2c_adapter(adapter))) 1150 depth++; 1151 1152 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES, 1153 "adapter depth exceeds lockdep subclass limit\n"); 1154 1155 return depth; 1156 } 1157 EXPORT_SYMBOL_GPL(i2c_adapter_depth); 1158 1159 /* 1160 * Let users instantiate I2C devices through sysfs. This can be used when 1161 * platform initialization code doesn't contain the proper data for 1162 * whatever reason. Also useful for drivers that do device detection and 1163 * detection fails, either because the device uses an unexpected address, 1164 * or this is a compatible device with different ID register values. 1165 * 1166 * Parameter checking may look overzealous, but we really don't want 1167 * the user to provide incorrect parameters. 1168 */ 1169 static ssize_t 1170 new_device_store(struct device *dev, struct device_attribute *attr, 1171 const char *buf, size_t count) 1172 { 1173 struct i2c_adapter *adap = to_i2c_adapter(dev); 1174 struct i2c_board_info info; 1175 struct i2c_client *client; 1176 char *blank, end; 1177 int res; 1178 1179 memset(&info, 0, sizeof(struct i2c_board_info)); 1180 1181 blank = strchr(buf, ' '); 1182 if (!blank) { 1183 dev_err(dev, "%s: Missing parameters\n", "new_device"); 1184 return -EINVAL; 1185 } 1186 if (blank - buf > I2C_NAME_SIZE - 1) { 1187 dev_err(dev, "%s: Invalid device name\n", "new_device"); 1188 return -EINVAL; 1189 } 1190 memcpy(info.type, buf, blank - buf); 1191 1192 /* Parse remaining parameters, reject extra parameters */ 1193 res = sscanf(++blank, "%hi%c", &info.addr, &end); 1194 if (res < 1) { 1195 dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); 1196 return -EINVAL; 1197 } 1198 if (res > 1 && end != '\n') { 1199 dev_err(dev, "%s: Extra parameters\n", "new_device"); 1200 return -EINVAL; 1201 } 1202 1203 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) { 1204 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT; 1205 info.flags |= I2C_CLIENT_TEN; 1206 } 1207 1208 if (info.addr & I2C_ADDR_OFFSET_SLAVE) { 1209 info.addr &= ~I2C_ADDR_OFFSET_SLAVE; 1210 info.flags |= I2C_CLIENT_SLAVE; 1211 } 1212 1213 client = i2c_new_client_device(adap, &info); 1214 if (IS_ERR(client)) 1215 return PTR_ERR(client); 1216 1217 /* Keep track of the added device */ 1218 mutex_lock(&adap->userspace_clients_lock); 1219 list_add_tail(&client->detected, &adap->userspace_clients); 1220 mutex_unlock(&adap->userspace_clients_lock); 1221 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", 1222 info.type, info.addr); 1223 1224 return count; 1225 } 1226 static DEVICE_ATTR_WO(new_device); 1227 1228 /* 1229 * And of course let the users delete the devices they instantiated, if 1230 * they got it wrong. This interface can only be used to delete devices 1231 * instantiated by i2c_sysfs_new_device above. This guarantees that we 1232 * don't delete devices to which some kernel code still has references. 1233 * 1234 * Parameter checking may look overzealous, but we really don't want 1235 * the user to delete the wrong device. 1236 */ 1237 static ssize_t 1238 delete_device_store(struct device *dev, struct device_attribute *attr, 1239 const char *buf, size_t count) 1240 { 1241 struct i2c_adapter *adap = to_i2c_adapter(dev); 1242 struct i2c_client *client, *next; 1243 unsigned short addr; 1244 char end; 1245 int res; 1246 1247 /* Parse parameters, reject extra parameters */ 1248 res = sscanf(buf, "%hi%c", &addr, &end); 1249 if (res < 1) { 1250 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); 1251 return -EINVAL; 1252 } 1253 if (res > 1 && end != '\n') { 1254 dev_err(dev, "%s: Extra parameters\n", "delete_device"); 1255 return -EINVAL; 1256 } 1257 1258 /* Make sure the device was added through sysfs */ 1259 res = -ENOENT; 1260 mutex_lock_nested(&adap->userspace_clients_lock, 1261 i2c_adapter_depth(adap)); 1262 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1263 detected) { 1264 if (i2c_encode_flags_to_addr(client) == addr) { 1265 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", 1266 "delete_device", client->name, client->addr); 1267 1268 list_del(&client->detected); 1269 i2c_unregister_device(client); 1270 res = count; 1271 break; 1272 } 1273 } 1274 mutex_unlock(&adap->userspace_clients_lock); 1275 1276 if (res < 0) 1277 dev_err(dev, "%s: Can't find device in list\n", 1278 "delete_device"); 1279 return res; 1280 } 1281 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL, 1282 delete_device_store); 1283 1284 static struct attribute *i2c_adapter_attrs[] = { 1285 &dev_attr_name.attr, 1286 &dev_attr_new_device.attr, 1287 &dev_attr_delete_device.attr, 1288 NULL 1289 }; 1290 ATTRIBUTE_GROUPS(i2c_adapter); 1291 1292 struct device_type i2c_adapter_type = { 1293 .groups = i2c_adapter_groups, 1294 .release = i2c_adapter_dev_release, 1295 }; 1296 EXPORT_SYMBOL_GPL(i2c_adapter_type); 1297 1298 /** 1299 * i2c_verify_adapter - return parameter as i2c_adapter or NULL 1300 * @dev: device, probably from some driver model iterator 1301 * 1302 * When traversing the driver model tree, perhaps using driver model 1303 * iterators like @device_for_each_child(), you can't assume very much 1304 * about the nodes you find. Use this function to avoid oopses caused 1305 * by wrongly treating some non-I2C device as an i2c_adapter. 1306 */ 1307 struct i2c_adapter *i2c_verify_adapter(struct device *dev) 1308 { 1309 return (dev->type == &i2c_adapter_type) 1310 ? to_i2c_adapter(dev) 1311 : NULL; 1312 } 1313 EXPORT_SYMBOL(i2c_verify_adapter); 1314 1315 #ifdef CONFIG_I2C_COMPAT 1316 static struct class_compat *i2c_adapter_compat_class; 1317 #endif 1318 1319 static void i2c_scan_static_board_info(struct i2c_adapter *adapter) 1320 { 1321 struct i2c_devinfo *devinfo; 1322 1323 down_read(&__i2c_board_lock); 1324 list_for_each_entry(devinfo, &__i2c_board_list, list) { 1325 if (devinfo->busnum == adapter->nr && 1326 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info))) 1327 dev_err(&adapter->dev, 1328 "Can't create device at 0x%02x\n", 1329 devinfo->board_info.addr); 1330 } 1331 up_read(&__i2c_board_lock); 1332 } 1333 1334 static int i2c_do_add_adapter(struct i2c_driver *driver, 1335 struct i2c_adapter *adap) 1336 { 1337 /* Detect supported devices on that bus, and instantiate them */ 1338 i2c_detect(adap, driver); 1339 1340 return 0; 1341 } 1342 1343 static int __process_new_adapter(struct device_driver *d, void *data) 1344 { 1345 return i2c_do_add_adapter(to_i2c_driver(d), data); 1346 } 1347 1348 static const struct i2c_lock_operations i2c_adapter_lock_ops = { 1349 .lock_bus = i2c_adapter_lock_bus, 1350 .trylock_bus = i2c_adapter_trylock_bus, 1351 .unlock_bus = i2c_adapter_unlock_bus, 1352 }; 1353 1354 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap) 1355 { 1356 struct irq_domain *domain = adap->host_notify_domain; 1357 irq_hw_number_t hwirq; 1358 1359 if (!domain) 1360 return; 1361 1362 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++) 1363 irq_dispose_mapping(irq_find_mapping(domain, hwirq)); 1364 1365 irq_domain_remove(domain); 1366 adap->host_notify_domain = NULL; 1367 } 1368 1369 static int i2c_host_notify_irq_map(struct irq_domain *h, 1370 unsigned int virq, 1371 irq_hw_number_t hw_irq_num) 1372 { 1373 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq); 1374 1375 return 0; 1376 } 1377 1378 static const struct irq_domain_ops i2c_host_notify_irq_ops = { 1379 .map = i2c_host_notify_irq_map, 1380 }; 1381 1382 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap) 1383 { 1384 struct irq_domain *domain; 1385 1386 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY)) 1387 return 0; 1388 1389 domain = irq_domain_create_linear(adap->dev.parent->fwnode, 1390 I2C_ADDR_7BITS_COUNT, 1391 &i2c_host_notify_irq_ops, adap); 1392 if (!domain) 1393 return -ENOMEM; 1394 1395 adap->host_notify_domain = domain; 1396 1397 return 0; 1398 } 1399 1400 /** 1401 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct 1402 * I2C client. 1403 * @adap: the adapter 1404 * @addr: the I2C address of the notifying device 1405 * Context: can't sleep 1406 * 1407 * Helper function to be called from an I2C bus driver's interrupt 1408 * handler. It will schedule the Host Notify IRQ. 1409 */ 1410 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr) 1411 { 1412 int irq; 1413 1414 if (!adap) 1415 return -EINVAL; 1416 1417 irq = irq_find_mapping(adap->host_notify_domain, addr); 1418 if (irq <= 0) 1419 return -ENXIO; 1420 1421 generic_handle_irq_safe(irq); 1422 1423 return 0; 1424 } 1425 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify); 1426 1427 static int i2c_register_adapter(struct i2c_adapter *adap) 1428 { 1429 int res = -EINVAL; 1430 1431 /* Can't register until after driver model init */ 1432 if (WARN_ON(!is_registered)) { 1433 res = -EAGAIN; 1434 goto out_list; 1435 } 1436 1437 /* Sanity checks */ 1438 if (WARN(!adap->name[0], "i2c adapter has no name")) 1439 goto out_list; 1440 1441 if (!adap->algo) { 1442 pr_err("adapter '%s': no algo supplied!\n", adap->name); 1443 goto out_list; 1444 } 1445 1446 if (!adap->lock_ops) 1447 adap->lock_ops = &i2c_adapter_lock_ops; 1448 1449 adap->locked_flags = 0; 1450 rt_mutex_init(&adap->bus_lock); 1451 rt_mutex_init(&adap->mux_lock); 1452 mutex_init(&adap->userspace_clients_lock); 1453 INIT_LIST_HEAD(&adap->userspace_clients); 1454 1455 /* Set default timeout to 1 second if not already set */ 1456 if (adap->timeout == 0) 1457 adap->timeout = HZ; 1458 1459 /* register soft irqs for Host Notify */ 1460 res = i2c_setup_host_notify_irq_domain(adap); 1461 if (res) { 1462 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n", 1463 adap->name, res); 1464 goto out_list; 1465 } 1466 1467 dev_set_name(&adap->dev, "i2c-%d", adap->nr); 1468 adap->dev.bus = &i2c_bus_type; 1469 adap->dev.type = &i2c_adapter_type; 1470 res = device_register(&adap->dev); 1471 if (res) { 1472 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); 1473 goto out_list; 1474 } 1475 1476 res = i2c_setup_smbus_alert(adap); 1477 if (res) 1478 goto out_reg; 1479 1480 device_enable_async_suspend(&adap->dev); 1481 pm_runtime_no_callbacks(&adap->dev); 1482 pm_suspend_ignore_children(&adap->dev, true); 1483 pm_runtime_enable(&adap->dev); 1484 1485 res = i2c_init_recovery(adap); 1486 if (res == -EPROBE_DEFER) 1487 goto out_reg; 1488 1489 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); 1490 1491 #ifdef CONFIG_I2C_COMPAT 1492 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, 1493 adap->dev.parent); 1494 if (res) 1495 dev_warn(&adap->dev, 1496 "Failed to create compatibility class link\n"); 1497 #endif 1498 1499 /* create pre-declared device nodes */ 1500 of_i2c_register_devices(adap); 1501 i2c_acpi_install_space_handler(adap); 1502 i2c_acpi_register_devices(adap); 1503 1504 if (adap->nr < __i2c_first_dynamic_bus_num) 1505 i2c_scan_static_board_info(adap); 1506 1507 /* Notify drivers */ 1508 mutex_lock(&core_lock); 1509 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); 1510 mutex_unlock(&core_lock); 1511 1512 return 0; 1513 1514 out_reg: 1515 init_completion(&adap->dev_released); 1516 device_unregister(&adap->dev); 1517 wait_for_completion(&adap->dev_released); 1518 out_list: 1519 mutex_lock(&core_lock); 1520 idr_remove(&i2c_adapter_idr, adap->nr); 1521 mutex_unlock(&core_lock); 1522 return res; 1523 } 1524 1525 /** 1526 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 1527 * @adap: the adapter to register (with adap->nr initialized) 1528 * Context: can sleep 1529 * 1530 * See i2c_add_numbered_adapter() for details. 1531 */ 1532 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) 1533 { 1534 int id; 1535 1536 mutex_lock(&core_lock); 1537 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); 1538 mutex_unlock(&core_lock); 1539 if (WARN(id < 0, "couldn't get idr")) 1540 return id == -ENOSPC ? -EBUSY : id; 1541 1542 return i2c_register_adapter(adap); 1543 } 1544 1545 /** 1546 * i2c_add_adapter - declare i2c adapter, use dynamic bus number 1547 * @adapter: the adapter to add 1548 * Context: can sleep 1549 * 1550 * This routine is used to declare an I2C adapter when its bus number 1551 * doesn't matter or when its bus number is specified by an dt alias. 1552 * Examples of bases when the bus number doesn't matter: I2C adapters 1553 * dynamically added by USB links or PCI plugin cards. 1554 * 1555 * When this returns zero, a new bus number was allocated and stored 1556 * in adap->nr, and the specified adapter became available for clients. 1557 * Otherwise, a negative errno value is returned. 1558 */ 1559 int i2c_add_adapter(struct i2c_adapter *adapter) 1560 { 1561 struct device *dev = &adapter->dev; 1562 int id; 1563 1564 if (dev->of_node) { 1565 id = of_alias_get_id(dev->of_node, "i2c"); 1566 if (id >= 0) { 1567 adapter->nr = id; 1568 return __i2c_add_numbered_adapter(adapter); 1569 } 1570 } 1571 1572 mutex_lock(&core_lock); 1573 id = idr_alloc(&i2c_adapter_idr, adapter, 1574 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); 1575 mutex_unlock(&core_lock); 1576 if (WARN(id < 0, "couldn't get idr")) 1577 return id; 1578 1579 adapter->nr = id; 1580 1581 return i2c_register_adapter(adapter); 1582 } 1583 EXPORT_SYMBOL(i2c_add_adapter); 1584 1585 /** 1586 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number 1587 * @adap: the adapter to register (with adap->nr initialized) 1588 * Context: can sleep 1589 * 1590 * This routine is used to declare an I2C adapter when its bus number 1591 * matters. For example, use it for I2C adapters from system-on-chip CPUs, 1592 * or otherwise built in to the system's mainboard, and where i2c_board_info 1593 * is used to properly configure I2C devices. 1594 * 1595 * If the requested bus number is set to -1, then this function will behave 1596 * identically to i2c_add_adapter, and will dynamically assign a bus number. 1597 * 1598 * If no devices have pre-been declared for this bus, then be sure to 1599 * register the adapter before any dynamically allocated ones. Otherwise 1600 * the required bus ID may not be available. 1601 * 1602 * When this returns zero, the specified adapter became available for 1603 * clients using the bus number provided in adap->nr. Also, the table 1604 * of I2C devices pre-declared using i2c_register_board_info() is scanned, 1605 * and the appropriate driver model device nodes are created. Otherwise, a 1606 * negative errno value is returned. 1607 */ 1608 int i2c_add_numbered_adapter(struct i2c_adapter *adap) 1609 { 1610 if (adap->nr == -1) /* -1 means dynamically assign bus id */ 1611 return i2c_add_adapter(adap); 1612 1613 return __i2c_add_numbered_adapter(adap); 1614 } 1615 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); 1616 1617 static void i2c_do_del_adapter(struct i2c_driver *driver, 1618 struct i2c_adapter *adapter) 1619 { 1620 struct i2c_client *client, *_n; 1621 1622 /* Remove the devices we created ourselves as the result of hardware 1623 * probing (using a driver's detect method) */ 1624 list_for_each_entry_safe(client, _n, &driver->clients, detected) { 1625 if (client->adapter == adapter) { 1626 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", 1627 client->name, client->addr); 1628 list_del(&client->detected); 1629 i2c_unregister_device(client); 1630 } 1631 } 1632 } 1633 1634 static int __unregister_client(struct device *dev, void *dummy) 1635 { 1636 struct i2c_client *client = i2c_verify_client(dev); 1637 if (client && strcmp(client->name, "dummy")) 1638 i2c_unregister_device(client); 1639 return 0; 1640 } 1641 1642 static int __unregister_dummy(struct device *dev, void *dummy) 1643 { 1644 struct i2c_client *client = i2c_verify_client(dev); 1645 i2c_unregister_device(client); 1646 return 0; 1647 } 1648 1649 static int __process_removed_adapter(struct device_driver *d, void *data) 1650 { 1651 i2c_do_del_adapter(to_i2c_driver(d), data); 1652 return 0; 1653 } 1654 1655 /** 1656 * i2c_del_adapter - unregister I2C adapter 1657 * @adap: the adapter being unregistered 1658 * Context: can sleep 1659 * 1660 * This unregisters an I2C adapter which was previously registered 1661 * by @i2c_add_adapter or @i2c_add_numbered_adapter. 1662 */ 1663 void i2c_del_adapter(struct i2c_adapter *adap) 1664 { 1665 struct i2c_adapter *found; 1666 struct i2c_client *client, *next; 1667 1668 /* First make sure that this adapter was ever added */ 1669 mutex_lock(&core_lock); 1670 found = idr_find(&i2c_adapter_idr, adap->nr); 1671 mutex_unlock(&core_lock); 1672 if (found != adap) { 1673 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); 1674 return; 1675 } 1676 1677 i2c_acpi_remove_space_handler(adap); 1678 /* Tell drivers about this removal */ 1679 mutex_lock(&core_lock); 1680 bus_for_each_drv(&i2c_bus_type, NULL, adap, 1681 __process_removed_adapter); 1682 mutex_unlock(&core_lock); 1683 1684 /* Remove devices instantiated from sysfs */ 1685 mutex_lock_nested(&adap->userspace_clients_lock, 1686 i2c_adapter_depth(adap)); 1687 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1688 detected) { 1689 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, 1690 client->addr); 1691 list_del(&client->detected); 1692 i2c_unregister_device(client); 1693 } 1694 mutex_unlock(&adap->userspace_clients_lock); 1695 1696 /* Detach any active clients. This can't fail, thus we do not 1697 * check the returned value. This is a two-pass process, because 1698 * we can't remove the dummy devices during the first pass: they 1699 * could have been instantiated by real devices wishing to clean 1700 * them up properly, so we give them a chance to do that first. */ 1701 device_for_each_child(&adap->dev, NULL, __unregister_client); 1702 device_for_each_child(&adap->dev, NULL, __unregister_dummy); 1703 1704 #ifdef CONFIG_I2C_COMPAT 1705 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, 1706 adap->dev.parent); 1707 #endif 1708 1709 /* device name is gone after device_unregister */ 1710 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); 1711 1712 pm_runtime_disable(&adap->dev); 1713 1714 i2c_host_notify_irq_teardown(adap); 1715 1716 /* wait until all references to the device are gone 1717 * 1718 * FIXME: This is old code and should ideally be replaced by an 1719 * alternative which results in decoupling the lifetime of the struct 1720 * device from the i2c_adapter, like spi or netdev do. Any solution 1721 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled! 1722 */ 1723 init_completion(&adap->dev_released); 1724 device_unregister(&adap->dev); 1725 wait_for_completion(&adap->dev_released); 1726 1727 /* free bus id */ 1728 mutex_lock(&core_lock); 1729 idr_remove(&i2c_adapter_idr, adap->nr); 1730 mutex_unlock(&core_lock); 1731 1732 /* Clear the device structure in case this adapter is ever going to be 1733 added again */ 1734 memset(&adap->dev, 0, sizeof(adap->dev)); 1735 } 1736 EXPORT_SYMBOL(i2c_del_adapter); 1737 1738 static void devm_i2c_del_adapter(void *adapter) 1739 { 1740 i2c_del_adapter(adapter); 1741 } 1742 1743 /** 1744 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter() 1745 * @dev: managing device for adding this I2C adapter 1746 * @adapter: the adapter to add 1747 * Context: can sleep 1748 * 1749 * Add adapter with dynamic bus number, same with i2c_add_adapter() 1750 * but the adapter will be auto deleted on driver detach. 1751 */ 1752 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter) 1753 { 1754 int ret; 1755 1756 ret = i2c_add_adapter(adapter); 1757 if (ret) 1758 return ret; 1759 1760 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter); 1761 } 1762 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter); 1763 1764 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p, 1765 u32 def_val, bool use_def) 1766 { 1767 int ret; 1768 1769 ret = device_property_read_u32(dev, prop_name, cur_val_p); 1770 if (ret && use_def) 1771 *cur_val_p = def_val; 1772 1773 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p); 1774 } 1775 1776 /** 1777 * i2c_parse_fw_timings - get I2C related timing parameters from firmware 1778 * @dev: The device to scan for I2C timing properties 1779 * @t: the i2c_timings struct to be filled with values 1780 * @use_defaults: bool to use sane defaults derived from the I2C specification 1781 * when properties are not found, otherwise don't update 1782 * 1783 * Scan the device for the generic I2C properties describing timing parameters 1784 * for the signal and fill the given struct with the results. If a property was 1785 * not found and use_defaults was true, then maximum timings are assumed which 1786 * are derived from the I2C specification. If use_defaults is not used, the 1787 * results will be as before, so drivers can apply their own defaults before 1788 * calling this helper. The latter is mainly intended for avoiding regressions 1789 * of existing drivers which want to switch to this function. New drivers 1790 * almost always should use the defaults. 1791 */ 1792 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) 1793 { 1794 bool u = use_defaults; 1795 u32 d; 1796 1797 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz, 1798 I2C_MAX_STANDARD_MODE_FREQ, u); 1799 1800 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 : 1801 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1802 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u); 1803 1804 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1805 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u); 1806 1807 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns", 1808 &t->scl_int_delay_ns, 0, u); 1809 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns, 1810 t->scl_fall_ns, u); 1811 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u); 1812 i2c_parse_timing(dev, "i2c-digital-filter-width-ns", 1813 &t->digital_filter_width_ns, 0, u); 1814 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency", 1815 &t->analog_filter_cutoff_freq_hz, 0, u); 1816 } 1817 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); 1818 1819 /* ------------------------------------------------------------------------- */ 1820 1821 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data)) 1822 { 1823 int res; 1824 1825 mutex_lock(&core_lock); 1826 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn); 1827 mutex_unlock(&core_lock); 1828 1829 return res; 1830 } 1831 EXPORT_SYMBOL_GPL(i2c_for_each_dev); 1832 1833 static int __process_new_driver(struct device *dev, void *data) 1834 { 1835 if (dev->type != &i2c_adapter_type) 1836 return 0; 1837 return i2c_do_add_adapter(data, to_i2c_adapter(dev)); 1838 } 1839 1840 /* 1841 * An i2c_driver is used with one or more i2c_client (device) nodes to access 1842 * i2c slave chips, on a bus instance associated with some i2c_adapter. 1843 */ 1844 1845 int i2c_register_driver(struct module *owner, struct i2c_driver *driver) 1846 { 1847 int res; 1848 1849 /* Can't register until after driver model init */ 1850 if (WARN_ON(!is_registered)) 1851 return -EAGAIN; 1852 1853 /* add the driver to the list of i2c drivers in the driver core */ 1854 driver->driver.owner = owner; 1855 driver->driver.bus = &i2c_bus_type; 1856 INIT_LIST_HEAD(&driver->clients); 1857 1858 /* When registration returns, the driver core 1859 * will have called probe() for all matching-but-unbound devices. 1860 */ 1861 res = driver_register(&driver->driver); 1862 if (res) 1863 return res; 1864 1865 pr_debug("driver [%s] registered\n", driver->driver.name); 1866 1867 /* Walk the adapters that are already present */ 1868 i2c_for_each_dev(driver, __process_new_driver); 1869 1870 return 0; 1871 } 1872 EXPORT_SYMBOL(i2c_register_driver); 1873 1874 static int __process_removed_driver(struct device *dev, void *data) 1875 { 1876 if (dev->type == &i2c_adapter_type) 1877 i2c_do_del_adapter(data, to_i2c_adapter(dev)); 1878 return 0; 1879 } 1880 1881 /** 1882 * i2c_del_driver - unregister I2C driver 1883 * @driver: the driver being unregistered 1884 * Context: can sleep 1885 */ 1886 void i2c_del_driver(struct i2c_driver *driver) 1887 { 1888 i2c_for_each_dev(driver, __process_removed_driver); 1889 1890 driver_unregister(&driver->driver); 1891 pr_debug("driver [%s] unregistered\n", driver->driver.name); 1892 } 1893 EXPORT_SYMBOL(i2c_del_driver); 1894 1895 /* ------------------------------------------------------------------------- */ 1896 1897 struct i2c_cmd_arg { 1898 unsigned cmd; 1899 void *arg; 1900 }; 1901 1902 static int i2c_cmd(struct device *dev, void *_arg) 1903 { 1904 struct i2c_client *client = i2c_verify_client(dev); 1905 struct i2c_cmd_arg *arg = _arg; 1906 struct i2c_driver *driver; 1907 1908 if (!client || !client->dev.driver) 1909 return 0; 1910 1911 driver = to_i2c_driver(client->dev.driver); 1912 if (driver->command) 1913 driver->command(client, arg->cmd, arg->arg); 1914 return 0; 1915 } 1916 1917 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) 1918 { 1919 struct i2c_cmd_arg cmd_arg; 1920 1921 cmd_arg.cmd = cmd; 1922 cmd_arg.arg = arg; 1923 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); 1924 } 1925 EXPORT_SYMBOL(i2c_clients_command); 1926 1927 static int __init i2c_init(void) 1928 { 1929 int retval; 1930 1931 retval = of_alias_get_highest_id("i2c"); 1932 1933 down_write(&__i2c_board_lock); 1934 if (retval >= __i2c_first_dynamic_bus_num) 1935 __i2c_first_dynamic_bus_num = retval + 1; 1936 up_write(&__i2c_board_lock); 1937 1938 retval = bus_register(&i2c_bus_type); 1939 if (retval) 1940 return retval; 1941 1942 is_registered = true; 1943 1944 #ifdef CONFIG_I2C_COMPAT 1945 i2c_adapter_compat_class = class_compat_register("i2c-adapter"); 1946 if (!i2c_adapter_compat_class) { 1947 retval = -ENOMEM; 1948 goto bus_err; 1949 } 1950 #endif 1951 retval = i2c_add_driver(&dummy_driver); 1952 if (retval) 1953 goto class_err; 1954 1955 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 1956 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); 1957 if (IS_ENABLED(CONFIG_ACPI)) 1958 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier)); 1959 1960 return 0; 1961 1962 class_err: 1963 #ifdef CONFIG_I2C_COMPAT 1964 class_compat_unregister(i2c_adapter_compat_class); 1965 bus_err: 1966 #endif 1967 is_registered = false; 1968 bus_unregister(&i2c_bus_type); 1969 return retval; 1970 } 1971 1972 static void __exit i2c_exit(void) 1973 { 1974 if (IS_ENABLED(CONFIG_ACPI)) 1975 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier)); 1976 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 1977 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier)); 1978 i2c_del_driver(&dummy_driver); 1979 #ifdef CONFIG_I2C_COMPAT 1980 class_compat_unregister(i2c_adapter_compat_class); 1981 #endif 1982 bus_unregister(&i2c_bus_type); 1983 tracepoint_synchronize_unregister(); 1984 } 1985 1986 /* We must initialize early, because some subsystems register i2c drivers 1987 * in subsys_initcall() code, but are linked (and initialized) before i2c. 1988 */ 1989 postcore_initcall(i2c_init); 1990 module_exit(i2c_exit); 1991 1992 /* ---------------------------------------------------- 1993 * the functional interface to the i2c busses. 1994 * ---------------------------------------------------- 1995 */ 1996 1997 /* Check if val is exceeding the quirk IFF quirk is non 0 */ 1998 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) 1999 2000 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) 2001 { 2002 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n", 2003 err_msg, msg->addr, msg->len, 2004 msg->flags & I2C_M_RD ? "read" : "write"); 2005 return -EOPNOTSUPP; 2006 } 2007 2008 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2009 { 2010 const struct i2c_adapter_quirks *q = adap->quirks; 2011 int max_num = q->max_num_msgs, i; 2012 bool do_len_check = true; 2013 2014 if (q->flags & I2C_AQ_COMB) { 2015 max_num = 2; 2016 2017 /* special checks for combined messages */ 2018 if (num == 2) { 2019 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD) 2020 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write"); 2021 2022 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD)) 2023 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read"); 2024 2025 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr) 2026 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr"); 2027 2028 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len)) 2029 return i2c_quirk_error(adap, &msgs[0], "msg too long"); 2030 2031 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len)) 2032 return i2c_quirk_error(adap, &msgs[1], "msg too long"); 2033 2034 do_len_check = false; 2035 } 2036 } 2037 2038 if (i2c_quirk_exceeded(num, max_num)) 2039 return i2c_quirk_error(adap, &msgs[0], "too many messages"); 2040 2041 for (i = 0; i < num; i++) { 2042 u16 len = msgs[i].len; 2043 2044 if (msgs[i].flags & I2C_M_RD) { 2045 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len)) 2046 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2047 2048 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0) 2049 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2050 } else { 2051 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len)) 2052 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2053 2054 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0) 2055 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2056 } 2057 } 2058 2059 return 0; 2060 } 2061 2062 /** 2063 * __i2c_transfer - unlocked flavor of i2c_transfer 2064 * @adap: Handle to I2C bus 2065 * @msgs: One or more messages to execute before STOP is issued to 2066 * terminate the operation; each message begins with a START. 2067 * @num: Number of messages to be executed. 2068 * 2069 * Returns negative errno, else the number of messages executed. 2070 * 2071 * Adapter lock must be held when calling this function. No debug logging 2072 * takes place. adap->algo->master_xfer existence isn't checked. 2073 */ 2074 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2075 { 2076 unsigned long orig_jiffies; 2077 int ret, try; 2078 2079 if (WARN_ON(!msgs || num < 1)) 2080 return -EINVAL; 2081 2082 ret = __i2c_check_suspended(adap); 2083 if (ret) 2084 return ret; 2085 2086 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) 2087 return -EOPNOTSUPP; 2088 2089 /* 2090 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets 2091 * enabled. This is an efficient way of keeping the for-loop from 2092 * being executed when not needed. 2093 */ 2094 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2095 int i; 2096 for (i = 0; i < num; i++) 2097 if (msgs[i].flags & I2C_M_RD) 2098 trace_i2c_read(adap, &msgs[i], i); 2099 else 2100 trace_i2c_write(adap, &msgs[i], i); 2101 } 2102 2103 /* Retry automatically on arbitration loss */ 2104 orig_jiffies = jiffies; 2105 for (ret = 0, try = 0; try <= adap->retries; try++) { 2106 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic) 2107 ret = adap->algo->master_xfer_atomic(adap, msgs, num); 2108 else 2109 ret = adap->algo->master_xfer(adap, msgs, num); 2110 2111 if (ret != -EAGAIN) 2112 break; 2113 if (time_after(jiffies, orig_jiffies + adap->timeout)) 2114 break; 2115 } 2116 2117 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2118 int i; 2119 for (i = 0; i < ret; i++) 2120 if (msgs[i].flags & I2C_M_RD) 2121 trace_i2c_reply(adap, &msgs[i], i); 2122 trace_i2c_result(adap, num, ret); 2123 } 2124 2125 return ret; 2126 } 2127 EXPORT_SYMBOL(__i2c_transfer); 2128 2129 /** 2130 * i2c_transfer - execute a single or combined I2C message 2131 * @adap: Handle to I2C bus 2132 * @msgs: One or more messages to execute before STOP is issued to 2133 * terminate the operation; each message begins with a START. 2134 * @num: Number of messages to be executed. 2135 * 2136 * Returns negative errno, else the number of messages executed. 2137 * 2138 * Note that there is no requirement that each message be sent to 2139 * the same slave address, although that is the most common model. 2140 */ 2141 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2142 { 2143 int ret; 2144 2145 if (!adap->algo->master_xfer) { 2146 dev_dbg(&adap->dev, "I2C level transfers not supported\n"); 2147 return -EOPNOTSUPP; 2148 } 2149 2150 /* REVISIT the fault reporting model here is weak: 2151 * 2152 * - When we get an error after receiving N bytes from a slave, 2153 * there is no way to report "N". 2154 * 2155 * - When we get a NAK after transmitting N bytes to a slave, 2156 * there is no way to report "N" ... or to let the master 2157 * continue executing the rest of this combined message, if 2158 * that's the appropriate response. 2159 * 2160 * - When for example "num" is two and we successfully complete 2161 * the first message but get an error part way through the 2162 * second, it's unclear whether that should be reported as 2163 * one (discarding status on the second message) or errno 2164 * (discarding status on the first one). 2165 */ 2166 ret = __i2c_lock_bus_helper(adap); 2167 if (ret) 2168 return ret; 2169 2170 ret = __i2c_transfer(adap, msgs, num); 2171 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); 2172 2173 return ret; 2174 } 2175 EXPORT_SYMBOL(i2c_transfer); 2176 2177 /** 2178 * i2c_transfer_buffer_flags - issue a single I2C message transferring data 2179 * to/from a buffer 2180 * @client: Handle to slave device 2181 * @buf: Where the data is stored 2182 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16 2183 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads 2184 * 2185 * Returns negative errno, or else the number of bytes transferred. 2186 */ 2187 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf, 2188 int count, u16 flags) 2189 { 2190 int ret; 2191 struct i2c_msg msg = { 2192 .addr = client->addr, 2193 .flags = flags | (client->flags & I2C_M_TEN), 2194 .len = count, 2195 .buf = buf, 2196 }; 2197 2198 ret = i2c_transfer(client->adapter, &msg, 1); 2199 2200 /* 2201 * If everything went ok (i.e. 1 msg transferred), return #bytes 2202 * transferred, else error code. 2203 */ 2204 return (ret == 1) ? count : ret; 2205 } 2206 EXPORT_SYMBOL(i2c_transfer_buffer_flags); 2207 2208 /** 2209 * i2c_get_device_id - get manufacturer, part id and die revision of a device 2210 * @client: The device to query 2211 * @id: The queried information 2212 * 2213 * Returns negative errno on error, zero on success. 2214 */ 2215 int i2c_get_device_id(const struct i2c_client *client, 2216 struct i2c_device_identity *id) 2217 { 2218 struct i2c_adapter *adap = client->adapter; 2219 union i2c_smbus_data raw_id; 2220 int ret; 2221 2222 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) 2223 return -EOPNOTSUPP; 2224 2225 raw_id.block[0] = 3; 2226 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0, 2227 I2C_SMBUS_READ, client->addr << 1, 2228 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id); 2229 if (ret) 2230 return ret; 2231 2232 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4); 2233 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3); 2234 id->die_revision = raw_id.block[3] & 0x7; 2235 return 0; 2236 } 2237 EXPORT_SYMBOL_GPL(i2c_get_device_id); 2238 2239 /* ---------------------------------------------------- 2240 * the i2c address scanning function 2241 * Will not work for 10-bit addresses! 2242 * ---------------------------------------------------- 2243 */ 2244 2245 /* 2246 * Legacy default probe function, mostly relevant for SMBus. The default 2247 * probe method is a quick write, but it is known to corrupt the 24RF08 2248 * EEPROMs due to a state machine bug, and could also irreversibly 2249 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f, 2250 * we use a short byte read instead. Also, some bus drivers don't implement 2251 * quick write, so we fallback to a byte read in that case too. 2252 * On x86, there is another special case for FSC hardware monitoring chips, 2253 * which want regular byte reads (address 0x73.) Fortunately, these are the 2254 * only known chips using this I2C address on PC hardware. 2255 * Returns 1 if probe succeeded, 0 if not. 2256 */ 2257 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) 2258 { 2259 int err; 2260 union i2c_smbus_data dummy; 2261 2262 #ifdef CONFIG_X86 2263 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON) 2264 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA)) 2265 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2266 I2C_SMBUS_BYTE_DATA, &dummy); 2267 else 2268 #endif 2269 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) 2270 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) 2271 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, 2272 I2C_SMBUS_QUICK, NULL); 2273 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) 2274 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2275 I2C_SMBUS_BYTE, &dummy); 2276 else { 2277 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n", 2278 addr); 2279 err = -EOPNOTSUPP; 2280 } 2281 2282 return err >= 0; 2283 } 2284 2285 static int i2c_detect_address(struct i2c_client *temp_client, 2286 struct i2c_driver *driver) 2287 { 2288 struct i2c_board_info info; 2289 struct i2c_adapter *adapter = temp_client->adapter; 2290 int addr = temp_client->addr; 2291 int err; 2292 2293 /* Make sure the address is valid */ 2294 err = i2c_check_7bit_addr_validity_strict(addr); 2295 if (err) { 2296 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n", 2297 addr); 2298 return err; 2299 } 2300 2301 /* Skip if already in use (7 bit, no need to encode flags) */ 2302 if (i2c_check_addr_busy(adapter, addr)) 2303 return 0; 2304 2305 /* Make sure there is something at this address */ 2306 if (!i2c_default_probe(adapter, addr)) 2307 return 0; 2308 2309 /* Finally call the custom detection function */ 2310 memset(&info, 0, sizeof(struct i2c_board_info)); 2311 info.addr = addr; 2312 err = driver->detect(temp_client, &info); 2313 if (err) { 2314 /* -ENODEV is returned if the detection fails. We catch it 2315 here as this isn't an error. */ 2316 return err == -ENODEV ? 0 : err; 2317 } 2318 2319 /* Consistency check */ 2320 if (info.type[0] == '\0') { 2321 dev_err(&adapter->dev, 2322 "%s detection function provided no name for 0x%x\n", 2323 driver->driver.name, addr); 2324 } else { 2325 struct i2c_client *client; 2326 2327 /* Detection succeeded, instantiate the device */ 2328 if (adapter->class & I2C_CLASS_DEPRECATED) 2329 dev_warn(&adapter->dev, 2330 "This adapter will soon drop class based instantiation of devices. " 2331 "Please make sure client 0x%02x gets instantiated by other means. " 2332 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n", 2333 info.addr); 2334 2335 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n", 2336 info.type, info.addr); 2337 client = i2c_new_client_device(adapter, &info); 2338 if (!IS_ERR(client)) 2339 list_add_tail(&client->detected, &driver->clients); 2340 else 2341 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n", 2342 info.type, info.addr); 2343 } 2344 return 0; 2345 } 2346 2347 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) 2348 { 2349 const unsigned short *address_list; 2350 struct i2c_client *temp_client; 2351 int i, err = 0; 2352 2353 address_list = driver->address_list; 2354 if (!driver->detect || !address_list) 2355 return 0; 2356 2357 /* Warn that the adapter lost class based instantiation */ 2358 if (adapter->class == I2C_CLASS_DEPRECATED) { 2359 dev_dbg(&adapter->dev, 2360 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. " 2361 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n", 2362 driver->driver.name); 2363 return 0; 2364 } 2365 2366 /* Stop here if the classes do not match */ 2367 if (!(adapter->class & driver->class)) 2368 return 0; 2369 2370 /* Set up a temporary client to help detect callback */ 2371 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); 2372 if (!temp_client) 2373 return -ENOMEM; 2374 temp_client->adapter = adapter; 2375 2376 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { 2377 dev_dbg(&adapter->dev, 2378 "found normal entry for adapter %d, addr 0x%02x\n", 2379 i2c_adapter_id(adapter), address_list[i]); 2380 temp_client->addr = address_list[i]; 2381 err = i2c_detect_address(temp_client, driver); 2382 if (unlikely(err)) 2383 break; 2384 } 2385 2386 kfree(temp_client); 2387 return err; 2388 } 2389 2390 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) 2391 { 2392 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2393 I2C_SMBUS_QUICK, NULL) >= 0; 2394 } 2395 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); 2396 2397 struct i2c_client * 2398 i2c_new_scanned_device(struct i2c_adapter *adap, 2399 struct i2c_board_info *info, 2400 unsigned short const *addr_list, 2401 int (*probe)(struct i2c_adapter *adap, unsigned short addr)) 2402 { 2403 int i; 2404 2405 if (!probe) 2406 probe = i2c_default_probe; 2407 2408 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { 2409 /* Check address validity */ 2410 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) { 2411 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n", 2412 addr_list[i]); 2413 continue; 2414 } 2415 2416 /* Check address availability (7 bit, no need to encode flags) */ 2417 if (i2c_check_addr_busy(adap, addr_list[i])) { 2418 dev_dbg(&adap->dev, 2419 "Address 0x%02x already in use, not probing\n", 2420 addr_list[i]); 2421 continue; 2422 } 2423 2424 /* Test address responsiveness */ 2425 if (probe(adap, addr_list[i])) 2426 break; 2427 } 2428 2429 if (addr_list[i] == I2C_CLIENT_END) { 2430 dev_dbg(&adap->dev, "Probing failed, no device found\n"); 2431 return ERR_PTR(-ENODEV); 2432 } 2433 2434 info->addr = addr_list[i]; 2435 return i2c_new_client_device(adap, info); 2436 } 2437 EXPORT_SYMBOL_GPL(i2c_new_scanned_device); 2438 2439 struct i2c_adapter *i2c_get_adapter(int nr) 2440 { 2441 struct i2c_adapter *adapter; 2442 2443 mutex_lock(&core_lock); 2444 adapter = idr_find(&i2c_adapter_idr, nr); 2445 if (!adapter) 2446 goto exit; 2447 2448 if (try_module_get(adapter->owner)) 2449 get_device(&adapter->dev); 2450 else 2451 adapter = NULL; 2452 2453 exit: 2454 mutex_unlock(&core_lock); 2455 return adapter; 2456 } 2457 EXPORT_SYMBOL(i2c_get_adapter); 2458 2459 void i2c_put_adapter(struct i2c_adapter *adap) 2460 { 2461 if (!adap) 2462 return; 2463 2464 module_put(adap->owner); 2465 /* Should be last, otherwise we risk use-after-free with 'adap' */ 2466 put_device(&adap->dev); 2467 } 2468 EXPORT_SYMBOL(i2c_put_adapter); 2469 2470 /** 2471 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg 2472 * @msg: the message to be checked 2473 * @threshold: the minimum number of bytes for which using DMA makes sense. 2474 * Should at least be 1. 2475 * 2476 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO. 2477 * Or a valid pointer to be used with DMA. After use, release it by 2478 * calling i2c_put_dma_safe_msg_buf(). 2479 * 2480 * This function must only be called from process context! 2481 */ 2482 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold) 2483 { 2484 /* also skip 0-length msgs for bogus thresholds of 0 */ 2485 if (!threshold) 2486 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n", 2487 msg->addr); 2488 if (msg->len < threshold || msg->len == 0) 2489 return NULL; 2490 2491 if (msg->flags & I2C_M_DMA_SAFE) 2492 return msg->buf; 2493 2494 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n", 2495 msg->addr, msg->len); 2496 2497 if (msg->flags & I2C_M_RD) 2498 return kzalloc(msg->len, GFP_KERNEL); 2499 else 2500 return kmemdup(msg->buf, msg->len, GFP_KERNEL); 2501 } 2502 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf); 2503 2504 /** 2505 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg 2506 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL. 2507 * @msg: the message which the buffer corresponds to 2508 * @xferred: bool saying if the message was transferred 2509 */ 2510 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred) 2511 { 2512 if (!buf || buf == msg->buf) 2513 return; 2514 2515 if (xferred && msg->flags & I2C_M_RD) 2516 memcpy(msg->buf, buf, msg->len); 2517 2518 kfree(buf); 2519 } 2520 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf); 2521 2522 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 2523 MODULE_DESCRIPTION("I2C-Bus main module"); 2524 MODULE_LICENSE("GPL"); 2525