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/debugfs.h> 20 #include <linux/delay.h> 21 #include <linux/err.h> 22 #include <linux/errno.h> 23 #include <linux/gpio/consumer.h> 24 #include <linux/i2c.h> 25 #include <linux/i2c-smbus.h> 26 #include <linux/idr.h> 27 #include <linux/init.h> 28 #include <linux/interrupt.h> 29 #include <linux/irqflags.h> 30 #include <linux/jump_label.h> 31 #include <linux/kernel.h> 32 #include <linux/module.h> 33 #include <linux/mutex.h> 34 #include <linux/of_device.h> 35 #include <linux/of.h> 36 #include <linux/of_irq.h> 37 #include <linux/pinctrl/consumer.h> 38 #include <linux/pinctrl/devinfo.h> 39 #include <linux/pm_domain.h> 40 #include <linux/pm_runtime.h> 41 #include <linux/pm_wakeirq.h> 42 #include <linux/property.h> 43 #include <linux/rwsem.h> 44 #include <linux/slab.h> 45 46 #include "i2c-core.h" 47 48 #define CREATE_TRACE_POINTS 49 #include <trace/events/i2c.h> 50 51 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000 52 #define I2C_ADDR_OFFSET_SLAVE 0x1000 53 54 #define I2C_ADDR_7BITS_MAX 0x77 55 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1) 56 57 #define I2C_ADDR_DEVICE_ID 0x7c 58 59 /* 60 * core_lock protects i2c_adapter_idr, and guarantees that device detection, 61 * deletion of detected devices are serialized 62 */ 63 static DEFINE_MUTEX(core_lock); 64 static DEFINE_IDR(i2c_adapter_idr); 65 66 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); 67 68 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key); 69 static bool is_registered; 70 71 static struct dentry *i2c_debugfs_root; 72 73 int i2c_transfer_trace_reg(void) 74 { 75 static_branch_inc(&i2c_trace_msg_key); 76 return 0; 77 } 78 79 void i2c_transfer_trace_unreg(void) 80 { 81 static_branch_dec(&i2c_trace_msg_key); 82 } 83 84 const char *i2c_freq_mode_string(u32 bus_freq_hz) 85 { 86 switch (bus_freq_hz) { 87 case I2C_MAX_STANDARD_MODE_FREQ: 88 return "Standard Mode (100 kHz)"; 89 case I2C_MAX_FAST_MODE_FREQ: 90 return "Fast Mode (400 kHz)"; 91 case I2C_MAX_FAST_MODE_PLUS_FREQ: 92 return "Fast Mode Plus (1.0 MHz)"; 93 case I2C_MAX_TURBO_MODE_FREQ: 94 return "Turbo Mode (1.4 MHz)"; 95 case I2C_MAX_HIGH_SPEED_MODE_FREQ: 96 return "High Speed Mode (3.4 MHz)"; 97 case I2C_MAX_ULTRA_FAST_MODE_FREQ: 98 return "Ultra Fast Mode (5.0 MHz)"; 99 default: 100 return "Unknown Mode"; 101 } 102 } 103 EXPORT_SYMBOL_GPL(i2c_freq_mode_string); 104 105 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, 106 const struct i2c_client *client) 107 { 108 if (!(id && client)) 109 return NULL; 110 111 while (id->name[0]) { 112 if (strcmp(client->name, id->name) == 0) 113 return id; 114 id++; 115 } 116 return NULL; 117 } 118 EXPORT_SYMBOL_GPL(i2c_match_id); 119 120 const void *i2c_get_match_data(const struct i2c_client *client) 121 { 122 struct i2c_driver *driver = to_i2c_driver(client->dev.driver); 123 const struct i2c_device_id *match; 124 const void *data; 125 126 data = device_get_match_data(&client->dev); 127 if (!data) { 128 match = i2c_match_id(driver->id_table, client); 129 if (!match) 130 return NULL; 131 132 data = (const void *)match->driver_data; 133 } 134 135 return data; 136 } 137 EXPORT_SYMBOL(i2c_get_match_data); 138 139 static int i2c_device_match(struct device *dev, struct device_driver *drv) 140 { 141 struct i2c_client *client = i2c_verify_client(dev); 142 struct i2c_driver *driver; 143 144 145 /* Attempt an OF style match */ 146 if (i2c_of_match_device(drv->of_match_table, client)) 147 return 1; 148 149 /* Then ACPI style match */ 150 if (acpi_driver_match_device(dev, drv)) 151 return 1; 152 153 driver = to_i2c_driver(drv); 154 155 /* Finally an I2C match */ 156 if (i2c_match_id(driver->id_table, client)) 157 return 1; 158 159 return 0; 160 } 161 162 static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env) 163 { 164 const struct i2c_client *client = to_i2c_client(dev); 165 int rc; 166 167 rc = of_device_uevent_modalias(dev, env); 168 if (rc != -ENODEV) 169 return rc; 170 171 rc = acpi_device_uevent_modalias(dev, env); 172 if (rc != -ENODEV) 173 return rc; 174 175 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name); 176 } 177 178 /* i2c bus recovery routines */ 179 static int get_scl_gpio_value(struct i2c_adapter *adap) 180 { 181 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod); 182 } 183 184 static void set_scl_gpio_value(struct i2c_adapter *adap, int val) 185 { 186 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val); 187 } 188 189 static int get_sda_gpio_value(struct i2c_adapter *adap) 190 { 191 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod); 192 } 193 194 static void set_sda_gpio_value(struct i2c_adapter *adap, int val) 195 { 196 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val); 197 } 198 199 static int i2c_generic_bus_free(struct i2c_adapter *adap) 200 { 201 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 202 int ret = -EOPNOTSUPP; 203 204 if (bri->get_bus_free) 205 ret = bri->get_bus_free(adap); 206 else if (bri->get_sda) 207 ret = bri->get_sda(adap); 208 209 if (ret < 0) 210 return ret; 211 212 return ret ? 0 : -EBUSY; 213 } 214 215 /* 216 * We are generating clock pulses. ndelay() determines durating of clk pulses. 217 * We will generate clock with rate 100 KHz and so duration of both clock levels 218 * is: delay in ns = (10^6 / 100) / 2 219 */ 220 #define RECOVERY_NDELAY 5000 221 #define RECOVERY_CLK_CNT 9 222 223 int i2c_generic_scl_recovery(struct i2c_adapter *adap) 224 { 225 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 226 int i = 0, scl = 1, ret = 0; 227 228 if (bri->prepare_recovery) 229 bri->prepare_recovery(adap); 230 if (bri->pinctrl) 231 pinctrl_select_state(bri->pinctrl, bri->pins_gpio); 232 233 /* 234 * If we can set SDA, we will always create a STOP to ensure additional 235 * pulses will do no harm. This is achieved by letting SDA follow SCL 236 * half a cycle later. Check the 'incomplete_write_byte' fault injector 237 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us 238 * here for simplicity. 239 */ 240 bri->set_scl(adap, scl); 241 ndelay(RECOVERY_NDELAY); 242 if (bri->set_sda) 243 bri->set_sda(adap, scl); 244 ndelay(RECOVERY_NDELAY / 2); 245 246 /* 247 * By this time SCL is high, as we need to give 9 falling-rising edges 248 */ 249 while (i++ < RECOVERY_CLK_CNT * 2) { 250 if (scl) { 251 /* SCL shouldn't be low here */ 252 if (!bri->get_scl(adap)) { 253 dev_err(&adap->dev, 254 "SCL is stuck low, exit recovery\n"); 255 ret = -EBUSY; 256 break; 257 } 258 } 259 260 scl = !scl; 261 bri->set_scl(adap, scl); 262 /* Creating STOP again, see above */ 263 if (scl) { 264 /* Honour minimum tsu:sto */ 265 ndelay(RECOVERY_NDELAY); 266 } else { 267 /* Honour minimum tf and thd:dat */ 268 ndelay(RECOVERY_NDELAY / 2); 269 } 270 if (bri->set_sda) 271 bri->set_sda(adap, scl); 272 ndelay(RECOVERY_NDELAY / 2); 273 274 if (scl) { 275 ret = i2c_generic_bus_free(adap); 276 if (ret == 0) 277 break; 278 } 279 } 280 281 /* If we can't check bus status, assume recovery worked */ 282 if (ret == -EOPNOTSUPP) 283 ret = 0; 284 285 if (bri->unprepare_recovery) 286 bri->unprepare_recovery(adap); 287 if (bri->pinctrl) 288 pinctrl_select_state(bri->pinctrl, bri->pins_default); 289 290 return ret; 291 } 292 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery); 293 294 int i2c_recover_bus(struct i2c_adapter *adap) 295 { 296 if (!adap->bus_recovery_info) 297 return -EBUSY; 298 299 dev_dbg(&adap->dev, "Trying i2c bus recovery\n"); 300 return adap->bus_recovery_info->recover_bus(adap); 301 } 302 EXPORT_SYMBOL_GPL(i2c_recover_bus); 303 304 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap) 305 { 306 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 307 struct device *dev = &adap->dev; 308 struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent); 309 310 bri->pinctrl = p; 311 312 /* 313 * we can't change states without pinctrl, so remove the states if 314 * populated 315 */ 316 if (!p) { 317 bri->pins_default = NULL; 318 bri->pins_gpio = NULL; 319 return; 320 } 321 322 if (!bri->pins_default) { 323 bri->pins_default = pinctrl_lookup_state(p, 324 PINCTRL_STATE_DEFAULT); 325 if (IS_ERR(bri->pins_default)) { 326 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n"); 327 bri->pins_default = NULL; 328 } 329 } 330 if (!bri->pins_gpio) { 331 bri->pins_gpio = pinctrl_lookup_state(p, "gpio"); 332 if (IS_ERR(bri->pins_gpio)) 333 bri->pins_gpio = pinctrl_lookup_state(p, "recovery"); 334 335 if (IS_ERR(bri->pins_gpio)) { 336 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n"); 337 bri->pins_gpio = NULL; 338 } 339 } 340 341 /* for pinctrl state changes, we need all the information */ 342 if (bri->pins_default && bri->pins_gpio) { 343 dev_info(dev, "using pinctrl states for GPIO recovery"); 344 } else { 345 bri->pinctrl = NULL; 346 bri->pins_default = NULL; 347 bri->pins_gpio = NULL; 348 } 349 } 350 351 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap) 352 { 353 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 354 struct device *dev = &adap->dev; 355 struct gpio_desc *gpiod; 356 int ret = 0; 357 358 /* 359 * don't touch the recovery information if the driver is not using 360 * generic SCL recovery 361 */ 362 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery) 363 return 0; 364 365 /* 366 * pins might be taken as GPIO, so we should inform pinctrl about 367 * this and move the state to GPIO 368 */ 369 if (bri->pinctrl) 370 pinctrl_select_state(bri->pinctrl, bri->pins_gpio); 371 372 /* 373 * if there is incomplete or no recovery information, see if generic 374 * GPIO recovery is available 375 */ 376 if (!bri->scl_gpiod) { 377 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); 378 if (PTR_ERR(gpiod) == -EPROBE_DEFER) { 379 ret = -EPROBE_DEFER; 380 goto cleanup_pinctrl_state; 381 } 382 if (!IS_ERR(gpiod)) { 383 bri->scl_gpiod = gpiod; 384 bri->recover_bus = i2c_generic_scl_recovery; 385 dev_info(dev, "using generic GPIOs for recovery\n"); 386 } 387 } 388 389 /* SDA GPIOD line is optional, so we care about DEFER only */ 390 if (!bri->sda_gpiod) { 391 /* 392 * We have SCL. Pull SCL low and wait a bit so that SDA glitches 393 * have no effect. 394 */ 395 gpiod_direction_output(bri->scl_gpiod, 0); 396 udelay(10); 397 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN); 398 399 /* Wait a bit in case of a SDA glitch, and then release SCL. */ 400 udelay(10); 401 gpiod_direction_output(bri->scl_gpiod, 1); 402 403 if (PTR_ERR(gpiod) == -EPROBE_DEFER) { 404 ret = -EPROBE_DEFER; 405 goto cleanup_pinctrl_state; 406 } 407 if (!IS_ERR(gpiod)) 408 bri->sda_gpiod = gpiod; 409 } 410 411 cleanup_pinctrl_state: 412 /* change the state of the pins back to their default state */ 413 if (bri->pinctrl) 414 pinctrl_select_state(bri->pinctrl, bri->pins_default); 415 416 return ret; 417 } 418 419 static int i2c_gpio_init_recovery(struct i2c_adapter *adap) 420 { 421 i2c_gpio_init_pinctrl_recovery(adap); 422 return i2c_gpio_init_generic_recovery(adap); 423 } 424 425 static int i2c_init_recovery(struct i2c_adapter *adap) 426 { 427 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 428 bool is_error_level = true; 429 char *err_str; 430 431 if (!bri) 432 return 0; 433 434 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER) 435 return -EPROBE_DEFER; 436 437 if (!bri->recover_bus) { 438 err_str = "no suitable method provided"; 439 is_error_level = false; 440 goto err; 441 } 442 443 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) { 444 bri->get_scl = get_scl_gpio_value; 445 bri->set_scl = set_scl_gpio_value; 446 if (bri->sda_gpiod) { 447 bri->get_sda = get_sda_gpio_value; 448 /* FIXME: add proper flag instead of '0' once available */ 449 if (gpiod_get_direction(bri->sda_gpiod) == 0) 450 bri->set_sda = set_sda_gpio_value; 451 } 452 } else if (bri->recover_bus == i2c_generic_scl_recovery) { 453 /* Generic SCL recovery */ 454 if (!bri->set_scl || !bri->get_scl) { 455 err_str = "no {get|set}_scl() found"; 456 goto err; 457 } 458 if (!bri->set_sda && !bri->get_sda) { 459 err_str = "either get_sda() or set_sda() needed"; 460 goto err; 461 } 462 } 463 464 return 0; 465 err: 466 if (is_error_level) 467 dev_err(&adap->dev, "Not using recovery: %s\n", err_str); 468 else 469 dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str); 470 adap->bus_recovery_info = NULL; 471 472 return -EINVAL; 473 } 474 475 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client) 476 { 477 struct i2c_adapter *adap = client->adapter; 478 unsigned int irq; 479 480 if (!adap->host_notify_domain) 481 return -ENXIO; 482 483 if (client->flags & I2C_CLIENT_TEN) 484 return -EINVAL; 485 486 irq = irq_create_mapping(adap->host_notify_domain, client->addr); 487 488 return irq > 0 ? irq : -ENXIO; 489 } 490 491 static int i2c_device_probe(struct device *dev) 492 { 493 struct i2c_client *client = i2c_verify_client(dev); 494 struct i2c_driver *driver; 495 bool do_power_on; 496 int status; 497 498 if (!client) 499 return 0; 500 501 client->irq = client->init_irq; 502 503 if (!client->irq) { 504 int irq = -ENOENT; 505 506 if (client->flags & I2C_CLIENT_HOST_NOTIFY) { 507 dev_dbg(dev, "Using Host Notify IRQ\n"); 508 /* Keep adapter active when Host Notify is required */ 509 pm_runtime_get_sync(&client->adapter->dev); 510 irq = i2c_smbus_host_notify_to_irq(client); 511 } else if (dev->of_node) { 512 irq = of_irq_get_byname(dev->of_node, "irq"); 513 if (irq == -EINVAL || irq == -ENODATA) 514 irq = of_irq_get(dev->of_node, 0); 515 } else if (ACPI_COMPANION(dev)) { 516 bool wake_capable; 517 518 irq = i2c_acpi_get_irq(client, &wake_capable); 519 if (irq > 0 && wake_capable) 520 client->flags |= I2C_CLIENT_WAKE; 521 } 522 if (irq == -EPROBE_DEFER) { 523 status = irq; 524 goto put_sync_adapter; 525 } 526 527 if (irq < 0) 528 irq = 0; 529 530 client->irq = irq; 531 } 532 533 driver = to_i2c_driver(dev->driver); 534 535 /* 536 * An I2C ID table is not mandatory, if and only if, a suitable OF 537 * or ACPI ID table is supplied for the probing device. 538 */ 539 if (!driver->id_table && 540 !acpi_driver_match_device(dev, dev->driver) && 541 !i2c_of_match_device(dev->driver->of_match_table, client)) { 542 status = -ENODEV; 543 goto put_sync_adapter; 544 } 545 546 if (client->flags & I2C_CLIENT_WAKE) { 547 int wakeirq; 548 549 wakeirq = of_irq_get_byname(dev->of_node, "wakeup"); 550 if (wakeirq == -EPROBE_DEFER) { 551 status = wakeirq; 552 goto put_sync_adapter; 553 } 554 555 device_init_wakeup(&client->dev, true); 556 557 if (wakeirq > 0 && wakeirq != client->irq) 558 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq); 559 else if (client->irq > 0) 560 status = dev_pm_set_wake_irq(dev, client->irq); 561 else 562 status = 0; 563 564 if (status) 565 dev_warn(&client->dev, "failed to set up wakeup irq\n"); 566 } 567 568 dev_dbg(dev, "probe\n"); 569 570 status = of_clk_set_defaults(dev->of_node, false); 571 if (status < 0) 572 goto err_clear_wakeup_irq; 573 574 do_power_on = !i2c_acpi_waive_d0_probe(dev); 575 status = dev_pm_domain_attach(&client->dev, do_power_on); 576 if (status) 577 goto err_clear_wakeup_irq; 578 579 client->devres_group_id = devres_open_group(&client->dev, NULL, 580 GFP_KERNEL); 581 if (!client->devres_group_id) { 582 status = -ENOMEM; 583 goto err_detach_pm_domain; 584 } 585 586 if (driver->probe) 587 status = driver->probe(client); 588 else 589 status = -EINVAL; 590 591 /* 592 * Note that we are not closing the devres group opened above so 593 * even resources that were attached to the device after probe is 594 * run are released when i2c_device_remove() is executed. This is 595 * needed as some drivers would allocate additional resources, 596 * for example when updating firmware. 597 */ 598 599 if (status) 600 goto err_release_driver_resources; 601 602 return 0; 603 604 err_release_driver_resources: 605 devres_release_group(&client->dev, client->devres_group_id); 606 err_detach_pm_domain: 607 dev_pm_domain_detach(&client->dev, do_power_on); 608 err_clear_wakeup_irq: 609 dev_pm_clear_wake_irq(&client->dev); 610 device_init_wakeup(&client->dev, false); 611 put_sync_adapter: 612 if (client->flags & I2C_CLIENT_HOST_NOTIFY) 613 pm_runtime_put_sync(&client->adapter->dev); 614 615 return status; 616 } 617 618 static void i2c_device_remove(struct device *dev) 619 { 620 struct i2c_client *client = to_i2c_client(dev); 621 struct i2c_driver *driver; 622 623 driver = to_i2c_driver(dev->driver); 624 if (driver->remove) { 625 dev_dbg(dev, "remove\n"); 626 627 driver->remove(client); 628 } 629 630 devres_release_group(&client->dev, client->devres_group_id); 631 632 dev_pm_domain_detach(&client->dev, true); 633 634 dev_pm_clear_wake_irq(&client->dev); 635 device_init_wakeup(&client->dev, false); 636 637 client->irq = 0; 638 if (client->flags & I2C_CLIENT_HOST_NOTIFY) 639 pm_runtime_put(&client->adapter->dev); 640 } 641 642 static void i2c_device_shutdown(struct device *dev) 643 { 644 struct i2c_client *client = i2c_verify_client(dev); 645 struct i2c_driver *driver; 646 647 if (!client || !dev->driver) 648 return; 649 driver = to_i2c_driver(dev->driver); 650 if (driver->shutdown) 651 driver->shutdown(client); 652 else if (client->irq > 0) 653 disable_irq(client->irq); 654 } 655 656 static void i2c_client_dev_release(struct device *dev) 657 { 658 kfree(to_i2c_client(dev)); 659 } 660 661 static ssize_t 662 name_show(struct device *dev, struct device_attribute *attr, char *buf) 663 { 664 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? 665 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); 666 } 667 static DEVICE_ATTR_RO(name); 668 669 static ssize_t 670 modalias_show(struct device *dev, struct device_attribute *attr, char *buf) 671 { 672 struct i2c_client *client = to_i2c_client(dev); 673 int len; 674 675 len = of_device_modalias(dev, buf, PAGE_SIZE); 676 if (len != -ENODEV) 677 return len; 678 679 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); 680 if (len != -ENODEV) 681 return len; 682 683 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); 684 } 685 static DEVICE_ATTR_RO(modalias); 686 687 static struct attribute *i2c_dev_attrs[] = { 688 &dev_attr_name.attr, 689 /* modalias helps coldplug: modprobe $(cat .../modalias) */ 690 &dev_attr_modalias.attr, 691 NULL 692 }; 693 ATTRIBUTE_GROUPS(i2c_dev); 694 695 const struct bus_type i2c_bus_type = { 696 .name = "i2c", 697 .match = i2c_device_match, 698 .probe = i2c_device_probe, 699 .remove = i2c_device_remove, 700 .shutdown = i2c_device_shutdown, 701 }; 702 EXPORT_SYMBOL_GPL(i2c_bus_type); 703 704 const struct device_type i2c_client_type = { 705 .groups = i2c_dev_groups, 706 .uevent = i2c_device_uevent, 707 .release = i2c_client_dev_release, 708 }; 709 EXPORT_SYMBOL_GPL(i2c_client_type); 710 711 712 /** 713 * i2c_verify_client - return parameter as i2c_client, or NULL 714 * @dev: device, probably from some driver model iterator 715 * 716 * When traversing the driver model tree, perhaps using driver model 717 * iterators like @device_for_each_child(), you can't assume very much 718 * about the nodes you find. Use this function to avoid oopses caused 719 * by wrongly treating some non-I2C device as an i2c_client. 720 */ 721 struct i2c_client *i2c_verify_client(struct device *dev) 722 { 723 return (dev->type == &i2c_client_type) 724 ? to_i2c_client(dev) 725 : NULL; 726 } 727 EXPORT_SYMBOL(i2c_verify_client); 728 729 730 /* Return a unique address which takes the flags of the client into account */ 731 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client) 732 { 733 unsigned short addr = client->addr; 734 735 /* For some client flags, add an arbitrary offset to avoid collisions */ 736 if (client->flags & I2C_CLIENT_TEN) 737 addr |= I2C_ADDR_OFFSET_TEN_BIT; 738 739 if (client->flags & I2C_CLIENT_SLAVE) 740 addr |= I2C_ADDR_OFFSET_SLAVE; 741 742 return addr; 743 } 744 745 /* This is a permissive address validity check, I2C address map constraints 746 * are purposely not enforced, except for the general call address. */ 747 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags) 748 { 749 if (flags & I2C_CLIENT_TEN) { 750 /* 10-bit address, all values are valid */ 751 if (addr > 0x3ff) 752 return -EINVAL; 753 } else { 754 /* 7-bit address, reject the general call address */ 755 if (addr == 0x00 || addr > 0x7f) 756 return -EINVAL; 757 } 758 return 0; 759 } 760 761 /* And this is a strict address validity check, used when probing. If a 762 * device uses a reserved address, then it shouldn't be probed. 7-bit 763 * addressing is assumed, 10-bit address devices are rare and should be 764 * explicitly enumerated. */ 765 int i2c_check_7bit_addr_validity_strict(unsigned short addr) 766 { 767 /* 768 * Reserved addresses per I2C specification: 769 * 0x00 General call address / START byte 770 * 0x01 CBUS address 771 * 0x02 Reserved for different bus format 772 * 0x03 Reserved for future purposes 773 * 0x04-0x07 Hs-mode master code 774 * 0x78-0x7b 10-bit slave addressing 775 * 0x7c-0x7f Reserved for future purposes 776 */ 777 if (addr < 0x08 || addr > 0x77) 778 return -EINVAL; 779 return 0; 780 } 781 782 static int __i2c_check_addr_busy(struct device *dev, void *addrp) 783 { 784 struct i2c_client *client = i2c_verify_client(dev); 785 int addr = *(int *)addrp; 786 787 if (client && i2c_encode_flags_to_addr(client) == addr) 788 return -EBUSY; 789 return 0; 790 } 791 792 /* walk up mux tree */ 793 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) 794 { 795 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 796 int result; 797 798 result = device_for_each_child(&adapter->dev, &addr, 799 __i2c_check_addr_busy); 800 801 if (!result && parent) 802 result = i2c_check_mux_parents(parent, addr); 803 804 return result; 805 } 806 807 /* recurse down mux tree */ 808 static int i2c_check_mux_children(struct device *dev, void *addrp) 809 { 810 int result; 811 812 if (dev->type == &i2c_adapter_type) 813 result = device_for_each_child(dev, addrp, 814 i2c_check_mux_children); 815 else 816 result = __i2c_check_addr_busy(dev, addrp); 817 818 return result; 819 } 820 821 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) 822 { 823 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 824 int result = 0; 825 826 if (parent) 827 result = i2c_check_mux_parents(parent, addr); 828 829 if (!result) 830 result = device_for_each_child(&adapter->dev, &addr, 831 i2c_check_mux_children); 832 833 return result; 834 } 835 836 /** 837 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment 838 * @adapter: Target I2C bus segment 839 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT 840 * locks only this branch in the adapter tree 841 */ 842 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, 843 unsigned int flags) 844 { 845 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); 846 } 847 848 /** 849 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment 850 * @adapter: Target I2C bus segment 851 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT 852 * trylocks only this branch in the adapter tree 853 */ 854 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, 855 unsigned int flags) 856 { 857 return rt_mutex_trylock(&adapter->bus_lock); 858 } 859 860 /** 861 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment 862 * @adapter: Target I2C bus segment 863 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT 864 * unlocks only this branch in the adapter tree 865 */ 866 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, 867 unsigned int flags) 868 { 869 rt_mutex_unlock(&adapter->bus_lock); 870 } 871 872 static void i2c_dev_set_name(struct i2c_adapter *adap, 873 struct i2c_client *client, 874 struct i2c_board_info const *info) 875 { 876 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 877 878 if (info && info->dev_name) { 879 dev_set_name(&client->dev, "i2c-%s", info->dev_name); 880 return; 881 } 882 883 if (adev) { 884 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev)); 885 return; 886 } 887 888 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), 889 i2c_encode_flags_to_addr(client)); 890 } 891 892 int i2c_dev_irq_from_resources(const struct resource *resources, 893 unsigned int num_resources) 894 { 895 struct irq_data *irqd; 896 int i; 897 898 for (i = 0; i < num_resources; i++) { 899 const struct resource *r = &resources[i]; 900 901 if (resource_type(r) != IORESOURCE_IRQ) 902 continue; 903 904 if (r->flags & IORESOURCE_BITS) { 905 irqd = irq_get_irq_data(r->start); 906 if (!irqd) 907 break; 908 909 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); 910 } 911 912 return r->start; 913 } 914 915 return 0; 916 } 917 918 /** 919 * i2c_new_client_device - instantiate an i2c device 920 * @adap: the adapter managing the device 921 * @info: describes one I2C device; bus_num is ignored 922 * Context: can sleep 923 * 924 * Create an i2c device. Binding is handled through driver model 925 * probe()/remove() methods. A driver may be bound to this device when we 926 * return from this function, or any later moment (e.g. maybe hotplugging will 927 * load the driver module). This call is not appropriate for use by mainboard 928 * initialization logic, which usually runs during an arch_initcall() long 929 * before any i2c_adapter could exist. 930 * 931 * This returns the new i2c client, which may be saved for later use with 932 * i2c_unregister_device(); or an ERR_PTR to describe the error. 933 */ 934 struct i2c_client * 935 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info) 936 { 937 struct i2c_client *client; 938 bool need_put = false; 939 int status; 940 941 client = kzalloc(sizeof *client, GFP_KERNEL); 942 if (!client) 943 return ERR_PTR(-ENOMEM); 944 945 client->adapter = adap; 946 947 client->dev.platform_data = info->platform_data; 948 client->flags = info->flags; 949 client->addr = info->addr; 950 951 client->init_irq = info->irq; 952 if (!client->init_irq) 953 client->init_irq = i2c_dev_irq_from_resources(info->resources, 954 info->num_resources); 955 956 strscpy(client->name, info->type, sizeof(client->name)); 957 958 status = i2c_check_addr_validity(client->addr, client->flags); 959 if (status) { 960 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", 961 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); 962 goto out_err_silent; 963 } 964 965 /* Check for address business */ 966 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); 967 if (status) 968 goto out_err; 969 970 client->dev.parent = &client->adapter->dev; 971 client->dev.bus = &i2c_bus_type; 972 client->dev.type = &i2c_client_type; 973 client->dev.of_node = of_node_get(info->of_node); 974 client->dev.fwnode = info->fwnode; 975 976 device_enable_async_suspend(&client->dev); 977 978 if (info->swnode) { 979 status = device_add_software_node(&client->dev, info->swnode); 980 if (status) { 981 dev_err(&adap->dev, 982 "Failed to add software node to client %s: %d\n", 983 client->name, status); 984 goto out_err_put_of_node; 985 } 986 } 987 988 i2c_dev_set_name(adap, client, info); 989 status = device_register(&client->dev); 990 if (status) 991 goto out_remove_swnode; 992 993 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", 994 client->name, dev_name(&client->dev)); 995 996 return client; 997 998 out_remove_swnode: 999 device_remove_software_node(&client->dev); 1000 need_put = true; 1001 out_err_put_of_node: 1002 of_node_put(info->of_node); 1003 out_err: 1004 dev_err(&adap->dev, 1005 "Failed to register i2c client %s at 0x%02x (%d)\n", 1006 client->name, client->addr, status); 1007 out_err_silent: 1008 if (need_put) 1009 put_device(&client->dev); 1010 else 1011 kfree(client); 1012 return ERR_PTR(status); 1013 } 1014 EXPORT_SYMBOL_GPL(i2c_new_client_device); 1015 1016 /** 1017 * i2c_unregister_device - reverse effect of i2c_new_*_device() 1018 * @client: value returned from i2c_new_*_device() 1019 * Context: can sleep 1020 */ 1021 void i2c_unregister_device(struct i2c_client *client) 1022 { 1023 if (IS_ERR_OR_NULL(client)) 1024 return; 1025 1026 if (client->dev.of_node) { 1027 of_node_clear_flag(client->dev.of_node, OF_POPULATED); 1028 of_node_put(client->dev.of_node); 1029 } 1030 1031 if (ACPI_COMPANION(&client->dev)) 1032 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev)); 1033 device_remove_software_node(&client->dev); 1034 device_unregister(&client->dev); 1035 } 1036 EXPORT_SYMBOL_GPL(i2c_unregister_device); 1037 1038 /** 1039 * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode 1040 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client 1041 * 1042 * Look up and return the &struct i2c_client corresponding to the @fwnode. 1043 * If no client can be found, or @fwnode is NULL, this returns NULL. 1044 * 1045 * The user must call put_device(&client->dev) once done with the i2c client. 1046 */ 1047 struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode) 1048 { 1049 struct i2c_client *client; 1050 struct device *dev; 1051 1052 if (!fwnode) 1053 return NULL; 1054 1055 dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode); 1056 if (!dev) 1057 return NULL; 1058 1059 client = i2c_verify_client(dev); 1060 if (!client) 1061 put_device(dev); 1062 1063 return client; 1064 } 1065 EXPORT_SYMBOL(i2c_find_device_by_fwnode); 1066 1067 1068 static const struct i2c_device_id dummy_id[] = { 1069 { "dummy", 0 }, 1070 { }, 1071 }; 1072 1073 static int dummy_probe(struct i2c_client *client) 1074 { 1075 return 0; 1076 } 1077 1078 static struct i2c_driver dummy_driver = { 1079 .driver.name = "dummy", 1080 .probe = dummy_probe, 1081 .id_table = dummy_id, 1082 }; 1083 1084 /** 1085 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1086 * @adapter: the adapter managing the device 1087 * @address: seven bit address to be used 1088 * Context: can sleep 1089 * 1090 * This returns an I2C client bound to the "dummy" driver, intended for use 1091 * with devices that consume multiple addresses. Examples of such chips 1092 * include various EEPROMS (like 24c04 and 24c08 models). 1093 * 1094 * These dummy devices have two main uses. First, most I2C and SMBus calls 1095 * except i2c_transfer() need a client handle; the dummy will be that handle. 1096 * And second, this prevents the specified address from being bound to a 1097 * different driver. 1098 * 1099 * This returns the new i2c client, which should be saved for later use with 1100 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1101 */ 1102 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address) 1103 { 1104 struct i2c_board_info info = { 1105 I2C_BOARD_INFO("dummy", address), 1106 }; 1107 1108 return i2c_new_client_device(adapter, &info); 1109 } 1110 EXPORT_SYMBOL_GPL(i2c_new_dummy_device); 1111 1112 static void devm_i2c_release_dummy(void *client) 1113 { 1114 i2c_unregister_device(client); 1115 } 1116 1117 /** 1118 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver 1119 * @dev: device the managed resource is bound to 1120 * @adapter: the adapter managing the device 1121 * @address: seven bit address to be used 1122 * Context: can sleep 1123 * 1124 * This is the device-managed version of @i2c_new_dummy_device. It returns the 1125 * new i2c client or an ERR_PTR in case of an error. 1126 */ 1127 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev, 1128 struct i2c_adapter *adapter, 1129 u16 address) 1130 { 1131 struct i2c_client *client; 1132 int ret; 1133 1134 client = i2c_new_dummy_device(adapter, address); 1135 if (IS_ERR(client)) 1136 return client; 1137 1138 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client); 1139 if (ret) 1140 return ERR_PTR(ret); 1141 1142 return client; 1143 } 1144 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device); 1145 1146 /** 1147 * i2c_new_ancillary_device - Helper to get the instantiated secondary address 1148 * and create the associated device 1149 * @client: Handle to the primary client 1150 * @name: Handle to specify which secondary address to get 1151 * @default_addr: Used as a fallback if no secondary address was specified 1152 * Context: can sleep 1153 * 1154 * I2C clients can be composed of multiple I2C slaves bound together in a single 1155 * component. The I2C client driver then binds to the master I2C slave and needs 1156 * to create I2C dummy clients to communicate with all the other slaves. 1157 * 1158 * This function creates and returns an I2C dummy client whose I2C address is 1159 * retrieved from the platform firmware based on the given slave name. If no 1160 * address is specified by the firmware default_addr is used. 1161 * 1162 * On DT-based platforms the address is retrieved from the "reg" property entry 1163 * cell whose "reg-names" value matches the slave name. 1164 * 1165 * This returns the new i2c client, which should be saved for later use with 1166 * i2c_unregister_device(); or an ERR_PTR to describe the error. 1167 */ 1168 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client, 1169 const char *name, 1170 u16 default_addr) 1171 { 1172 struct device_node *np = client->dev.of_node; 1173 u32 addr = default_addr; 1174 int i; 1175 1176 if (np) { 1177 i = of_property_match_string(np, "reg-names", name); 1178 if (i >= 0) 1179 of_property_read_u32_index(np, "reg", i, &addr); 1180 } 1181 1182 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); 1183 return i2c_new_dummy_device(client->adapter, addr); 1184 } 1185 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device); 1186 1187 /* ------------------------------------------------------------------------- */ 1188 1189 /* I2C bus adapters -- one roots each I2C or SMBUS segment */ 1190 1191 static void i2c_adapter_dev_release(struct device *dev) 1192 { 1193 struct i2c_adapter *adap = to_i2c_adapter(dev); 1194 complete(&adap->dev_released); 1195 } 1196 1197 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) 1198 { 1199 unsigned int depth = 0; 1200 struct device *parent; 1201 1202 for (parent = adapter->dev.parent; parent; parent = parent->parent) 1203 if (parent->type == &i2c_adapter_type) 1204 depth++; 1205 1206 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES, 1207 "adapter depth exceeds lockdep subclass limit\n"); 1208 1209 return depth; 1210 } 1211 EXPORT_SYMBOL_GPL(i2c_adapter_depth); 1212 1213 /* 1214 * Let users instantiate I2C devices through sysfs. This can be used when 1215 * platform initialization code doesn't contain the proper data for 1216 * whatever reason. Also useful for drivers that do device detection and 1217 * detection fails, either because the device uses an unexpected address, 1218 * or this is a compatible device with different ID register values. 1219 * 1220 * Parameter checking may look overzealous, but we really don't want 1221 * the user to provide incorrect parameters. 1222 */ 1223 static ssize_t 1224 new_device_store(struct device *dev, struct device_attribute *attr, 1225 const char *buf, size_t count) 1226 { 1227 struct i2c_adapter *adap = to_i2c_adapter(dev); 1228 struct i2c_board_info info; 1229 struct i2c_client *client; 1230 char *blank, end; 1231 int res; 1232 1233 memset(&info, 0, sizeof(struct i2c_board_info)); 1234 1235 blank = strchr(buf, ' '); 1236 if (!blank) { 1237 dev_err(dev, "%s: Missing parameters\n", "new_device"); 1238 return -EINVAL; 1239 } 1240 if (blank - buf > I2C_NAME_SIZE - 1) { 1241 dev_err(dev, "%s: Invalid device name\n", "new_device"); 1242 return -EINVAL; 1243 } 1244 memcpy(info.type, buf, blank - buf); 1245 1246 /* Parse remaining parameters, reject extra parameters */ 1247 res = sscanf(++blank, "%hi%c", &info.addr, &end); 1248 if (res < 1) { 1249 dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); 1250 return -EINVAL; 1251 } 1252 if (res > 1 && end != '\n') { 1253 dev_err(dev, "%s: Extra parameters\n", "new_device"); 1254 return -EINVAL; 1255 } 1256 1257 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) { 1258 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT; 1259 info.flags |= I2C_CLIENT_TEN; 1260 } 1261 1262 if (info.addr & I2C_ADDR_OFFSET_SLAVE) { 1263 info.addr &= ~I2C_ADDR_OFFSET_SLAVE; 1264 info.flags |= I2C_CLIENT_SLAVE; 1265 } 1266 1267 client = i2c_new_client_device(adap, &info); 1268 if (IS_ERR(client)) 1269 return PTR_ERR(client); 1270 1271 /* Keep track of the added device */ 1272 mutex_lock(&adap->userspace_clients_lock); 1273 list_add_tail(&client->detected, &adap->userspace_clients); 1274 mutex_unlock(&adap->userspace_clients_lock); 1275 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", 1276 info.type, info.addr); 1277 1278 return count; 1279 } 1280 static DEVICE_ATTR_WO(new_device); 1281 1282 /* 1283 * And of course let the users delete the devices they instantiated, if 1284 * they got it wrong. This interface can only be used to delete devices 1285 * instantiated by i2c_sysfs_new_device above. This guarantees that we 1286 * don't delete devices to which some kernel code still has references. 1287 * 1288 * Parameter checking may look overzealous, but we really don't want 1289 * the user to delete the wrong device. 1290 */ 1291 static ssize_t 1292 delete_device_store(struct device *dev, struct device_attribute *attr, 1293 const char *buf, size_t count) 1294 { 1295 struct i2c_adapter *adap = to_i2c_adapter(dev); 1296 struct i2c_client *client, *next; 1297 unsigned short addr; 1298 char end; 1299 int res; 1300 1301 /* Parse parameters, reject extra parameters */ 1302 res = sscanf(buf, "%hi%c", &addr, &end); 1303 if (res < 1) { 1304 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); 1305 return -EINVAL; 1306 } 1307 if (res > 1 && end != '\n') { 1308 dev_err(dev, "%s: Extra parameters\n", "delete_device"); 1309 return -EINVAL; 1310 } 1311 1312 /* Make sure the device was added through sysfs */ 1313 res = -ENOENT; 1314 mutex_lock_nested(&adap->userspace_clients_lock, 1315 i2c_adapter_depth(adap)); 1316 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1317 detected) { 1318 if (i2c_encode_flags_to_addr(client) == addr) { 1319 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", 1320 "delete_device", client->name, client->addr); 1321 1322 list_del(&client->detected); 1323 i2c_unregister_device(client); 1324 res = count; 1325 break; 1326 } 1327 } 1328 mutex_unlock(&adap->userspace_clients_lock); 1329 1330 if (res < 0) 1331 dev_err(dev, "%s: Can't find device in list\n", 1332 "delete_device"); 1333 return res; 1334 } 1335 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL, 1336 delete_device_store); 1337 1338 static struct attribute *i2c_adapter_attrs[] = { 1339 &dev_attr_name.attr, 1340 &dev_attr_new_device.attr, 1341 &dev_attr_delete_device.attr, 1342 NULL 1343 }; 1344 ATTRIBUTE_GROUPS(i2c_adapter); 1345 1346 const struct device_type i2c_adapter_type = { 1347 .groups = i2c_adapter_groups, 1348 .release = i2c_adapter_dev_release, 1349 }; 1350 EXPORT_SYMBOL_GPL(i2c_adapter_type); 1351 1352 /** 1353 * i2c_verify_adapter - return parameter as i2c_adapter or NULL 1354 * @dev: device, probably from some driver model iterator 1355 * 1356 * When traversing the driver model tree, perhaps using driver model 1357 * iterators like @device_for_each_child(), you can't assume very much 1358 * about the nodes you find. Use this function to avoid oopses caused 1359 * by wrongly treating some non-I2C device as an i2c_adapter. 1360 */ 1361 struct i2c_adapter *i2c_verify_adapter(struct device *dev) 1362 { 1363 return (dev->type == &i2c_adapter_type) 1364 ? to_i2c_adapter(dev) 1365 : NULL; 1366 } 1367 EXPORT_SYMBOL(i2c_verify_adapter); 1368 1369 #ifdef CONFIG_I2C_COMPAT 1370 static struct class_compat *i2c_adapter_compat_class; 1371 #endif 1372 1373 static void i2c_scan_static_board_info(struct i2c_adapter *adapter) 1374 { 1375 struct i2c_devinfo *devinfo; 1376 1377 down_read(&__i2c_board_lock); 1378 list_for_each_entry(devinfo, &__i2c_board_list, list) { 1379 if (devinfo->busnum == adapter->nr && 1380 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info))) 1381 dev_err(&adapter->dev, 1382 "Can't create device at 0x%02x\n", 1383 devinfo->board_info.addr); 1384 } 1385 up_read(&__i2c_board_lock); 1386 } 1387 1388 static int i2c_do_add_adapter(struct i2c_driver *driver, 1389 struct i2c_adapter *adap) 1390 { 1391 /* Detect supported devices on that bus, and instantiate them */ 1392 i2c_detect(adap, driver); 1393 1394 return 0; 1395 } 1396 1397 static int __process_new_adapter(struct device_driver *d, void *data) 1398 { 1399 return i2c_do_add_adapter(to_i2c_driver(d), data); 1400 } 1401 1402 static const struct i2c_lock_operations i2c_adapter_lock_ops = { 1403 .lock_bus = i2c_adapter_lock_bus, 1404 .trylock_bus = i2c_adapter_trylock_bus, 1405 .unlock_bus = i2c_adapter_unlock_bus, 1406 }; 1407 1408 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap) 1409 { 1410 struct irq_domain *domain = adap->host_notify_domain; 1411 irq_hw_number_t hwirq; 1412 1413 if (!domain) 1414 return; 1415 1416 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++) 1417 irq_dispose_mapping(irq_find_mapping(domain, hwirq)); 1418 1419 irq_domain_remove(domain); 1420 adap->host_notify_domain = NULL; 1421 } 1422 1423 static int i2c_host_notify_irq_map(struct irq_domain *h, 1424 unsigned int virq, 1425 irq_hw_number_t hw_irq_num) 1426 { 1427 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq); 1428 1429 return 0; 1430 } 1431 1432 static const struct irq_domain_ops i2c_host_notify_irq_ops = { 1433 .map = i2c_host_notify_irq_map, 1434 }; 1435 1436 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap) 1437 { 1438 struct irq_domain *domain; 1439 1440 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY)) 1441 return 0; 1442 1443 domain = irq_domain_create_linear(adap->dev.parent->fwnode, 1444 I2C_ADDR_7BITS_COUNT, 1445 &i2c_host_notify_irq_ops, adap); 1446 if (!domain) 1447 return -ENOMEM; 1448 1449 adap->host_notify_domain = domain; 1450 1451 return 0; 1452 } 1453 1454 /** 1455 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct 1456 * I2C client. 1457 * @adap: the adapter 1458 * @addr: the I2C address of the notifying device 1459 * Context: can't sleep 1460 * 1461 * Helper function to be called from an I2C bus driver's interrupt 1462 * handler. It will schedule the Host Notify IRQ. 1463 */ 1464 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr) 1465 { 1466 int irq; 1467 1468 if (!adap) 1469 return -EINVAL; 1470 1471 irq = irq_find_mapping(adap->host_notify_domain, addr); 1472 if (irq <= 0) 1473 return -ENXIO; 1474 1475 generic_handle_irq_safe(irq); 1476 1477 return 0; 1478 } 1479 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify); 1480 1481 static int i2c_register_adapter(struct i2c_adapter *adap) 1482 { 1483 int res = -EINVAL; 1484 1485 /* Can't register until after driver model init */ 1486 if (WARN_ON(!is_registered)) { 1487 res = -EAGAIN; 1488 goto out_list; 1489 } 1490 1491 /* Sanity checks */ 1492 if (WARN(!adap->name[0], "i2c adapter has no name")) 1493 goto out_list; 1494 1495 if (!adap->algo) { 1496 pr_err("adapter '%s': no algo supplied!\n", adap->name); 1497 goto out_list; 1498 } 1499 1500 if (!adap->lock_ops) 1501 adap->lock_ops = &i2c_adapter_lock_ops; 1502 1503 adap->locked_flags = 0; 1504 rt_mutex_init(&adap->bus_lock); 1505 rt_mutex_init(&adap->mux_lock); 1506 mutex_init(&adap->userspace_clients_lock); 1507 INIT_LIST_HEAD(&adap->userspace_clients); 1508 1509 /* Set default timeout to 1 second if not already set */ 1510 if (adap->timeout == 0) 1511 adap->timeout = HZ; 1512 1513 /* register soft irqs for Host Notify */ 1514 res = i2c_setup_host_notify_irq_domain(adap); 1515 if (res) { 1516 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n", 1517 adap->name, res); 1518 goto out_list; 1519 } 1520 1521 dev_set_name(&adap->dev, "i2c-%d", adap->nr); 1522 adap->dev.bus = &i2c_bus_type; 1523 adap->dev.type = &i2c_adapter_type; 1524 res = device_register(&adap->dev); 1525 if (res) { 1526 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); 1527 goto out_list; 1528 } 1529 1530 adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root); 1531 1532 res = i2c_setup_smbus_alert(adap); 1533 if (res) 1534 goto out_reg; 1535 1536 device_enable_async_suspend(&adap->dev); 1537 pm_runtime_no_callbacks(&adap->dev); 1538 pm_suspend_ignore_children(&adap->dev, true); 1539 pm_runtime_enable(&adap->dev); 1540 1541 res = i2c_init_recovery(adap); 1542 if (res == -EPROBE_DEFER) 1543 goto out_reg; 1544 1545 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); 1546 1547 #ifdef CONFIG_I2C_COMPAT 1548 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, 1549 adap->dev.parent); 1550 if (res) 1551 dev_warn(&adap->dev, 1552 "Failed to create compatibility class link\n"); 1553 #endif 1554 1555 /* create pre-declared device nodes */ 1556 of_i2c_register_devices(adap); 1557 i2c_acpi_install_space_handler(adap); 1558 i2c_acpi_register_devices(adap); 1559 1560 if (adap->nr < __i2c_first_dynamic_bus_num) 1561 i2c_scan_static_board_info(adap); 1562 1563 /* Notify drivers */ 1564 mutex_lock(&core_lock); 1565 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); 1566 mutex_unlock(&core_lock); 1567 1568 return 0; 1569 1570 out_reg: 1571 debugfs_remove_recursive(adap->debugfs); 1572 init_completion(&adap->dev_released); 1573 device_unregister(&adap->dev); 1574 wait_for_completion(&adap->dev_released); 1575 out_list: 1576 mutex_lock(&core_lock); 1577 idr_remove(&i2c_adapter_idr, adap->nr); 1578 mutex_unlock(&core_lock); 1579 return res; 1580 } 1581 1582 /** 1583 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 1584 * @adap: the adapter to register (with adap->nr initialized) 1585 * Context: can sleep 1586 * 1587 * See i2c_add_numbered_adapter() for details. 1588 */ 1589 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) 1590 { 1591 int id; 1592 1593 mutex_lock(&core_lock); 1594 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); 1595 mutex_unlock(&core_lock); 1596 if (WARN(id < 0, "couldn't get idr")) 1597 return id == -ENOSPC ? -EBUSY : id; 1598 1599 return i2c_register_adapter(adap); 1600 } 1601 1602 /** 1603 * i2c_add_adapter - declare i2c adapter, use dynamic bus number 1604 * @adapter: the adapter to add 1605 * Context: can sleep 1606 * 1607 * This routine is used to declare an I2C adapter when its bus number 1608 * doesn't matter or when its bus number is specified by an dt alias. 1609 * Examples of bases when the bus number doesn't matter: I2C adapters 1610 * dynamically added by USB links or PCI plugin cards. 1611 * 1612 * When this returns zero, a new bus number was allocated and stored 1613 * in adap->nr, and the specified adapter became available for clients. 1614 * Otherwise, a negative errno value is returned. 1615 */ 1616 int i2c_add_adapter(struct i2c_adapter *adapter) 1617 { 1618 struct device *dev = &adapter->dev; 1619 int id; 1620 1621 if (dev->of_node) { 1622 id = of_alias_get_id(dev->of_node, "i2c"); 1623 if (id >= 0) { 1624 adapter->nr = id; 1625 return __i2c_add_numbered_adapter(adapter); 1626 } 1627 } 1628 1629 mutex_lock(&core_lock); 1630 id = idr_alloc(&i2c_adapter_idr, adapter, 1631 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); 1632 mutex_unlock(&core_lock); 1633 if (WARN(id < 0, "couldn't get idr")) 1634 return id; 1635 1636 adapter->nr = id; 1637 1638 return i2c_register_adapter(adapter); 1639 } 1640 EXPORT_SYMBOL(i2c_add_adapter); 1641 1642 /** 1643 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number 1644 * @adap: the adapter to register (with adap->nr initialized) 1645 * Context: can sleep 1646 * 1647 * This routine is used to declare an I2C adapter when its bus number 1648 * matters. For example, use it for I2C adapters from system-on-chip CPUs, 1649 * or otherwise built in to the system's mainboard, and where i2c_board_info 1650 * is used to properly configure I2C devices. 1651 * 1652 * If the requested bus number is set to -1, then this function will behave 1653 * identically to i2c_add_adapter, and will dynamically assign a bus number. 1654 * 1655 * If no devices have pre-been declared for this bus, then be sure to 1656 * register the adapter before any dynamically allocated ones. Otherwise 1657 * the required bus ID may not be available. 1658 * 1659 * When this returns zero, the specified adapter became available for 1660 * clients using the bus number provided in adap->nr. Also, the table 1661 * of I2C devices pre-declared using i2c_register_board_info() is scanned, 1662 * and the appropriate driver model device nodes are created. Otherwise, a 1663 * negative errno value is returned. 1664 */ 1665 int i2c_add_numbered_adapter(struct i2c_adapter *adap) 1666 { 1667 if (adap->nr == -1) /* -1 means dynamically assign bus id */ 1668 return i2c_add_adapter(adap); 1669 1670 return __i2c_add_numbered_adapter(adap); 1671 } 1672 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); 1673 1674 static void i2c_do_del_adapter(struct i2c_driver *driver, 1675 struct i2c_adapter *adapter) 1676 { 1677 struct i2c_client *client, *_n; 1678 1679 /* Remove the devices we created ourselves as the result of hardware 1680 * probing (using a driver's detect method) */ 1681 list_for_each_entry_safe(client, _n, &driver->clients, detected) { 1682 if (client->adapter == adapter) { 1683 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", 1684 client->name, client->addr); 1685 list_del(&client->detected); 1686 i2c_unregister_device(client); 1687 } 1688 } 1689 } 1690 1691 static int __unregister_client(struct device *dev, void *dummy) 1692 { 1693 struct i2c_client *client = i2c_verify_client(dev); 1694 if (client && strcmp(client->name, "dummy")) 1695 i2c_unregister_device(client); 1696 return 0; 1697 } 1698 1699 static int __unregister_dummy(struct device *dev, void *dummy) 1700 { 1701 struct i2c_client *client = i2c_verify_client(dev); 1702 i2c_unregister_device(client); 1703 return 0; 1704 } 1705 1706 static int __process_removed_adapter(struct device_driver *d, void *data) 1707 { 1708 i2c_do_del_adapter(to_i2c_driver(d), data); 1709 return 0; 1710 } 1711 1712 /** 1713 * i2c_del_adapter - unregister I2C adapter 1714 * @adap: the adapter being unregistered 1715 * Context: can sleep 1716 * 1717 * This unregisters an I2C adapter which was previously registered 1718 * by @i2c_add_adapter or @i2c_add_numbered_adapter. 1719 */ 1720 void i2c_del_adapter(struct i2c_adapter *adap) 1721 { 1722 struct i2c_adapter *found; 1723 struct i2c_client *client, *next; 1724 1725 /* First make sure that this adapter was ever added */ 1726 mutex_lock(&core_lock); 1727 found = idr_find(&i2c_adapter_idr, adap->nr); 1728 mutex_unlock(&core_lock); 1729 if (found != adap) { 1730 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); 1731 return; 1732 } 1733 1734 i2c_acpi_remove_space_handler(adap); 1735 /* Tell drivers about this removal */ 1736 mutex_lock(&core_lock); 1737 bus_for_each_drv(&i2c_bus_type, NULL, adap, 1738 __process_removed_adapter); 1739 mutex_unlock(&core_lock); 1740 1741 /* Remove devices instantiated from sysfs */ 1742 mutex_lock_nested(&adap->userspace_clients_lock, 1743 i2c_adapter_depth(adap)); 1744 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1745 detected) { 1746 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, 1747 client->addr); 1748 list_del(&client->detected); 1749 i2c_unregister_device(client); 1750 } 1751 mutex_unlock(&adap->userspace_clients_lock); 1752 1753 /* Detach any active clients. This can't fail, thus we do not 1754 * check the returned value. This is a two-pass process, because 1755 * we can't remove the dummy devices during the first pass: they 1756 * could have been instantiated by real devices wishing to clean 1757 * them up properly, so we give them a chance to do that first. */ 1758 device_for_each_child(&adap->dev, NULL, __unregister_client); 1759 device_for_each_child(&adap->dev, NULL, __unregister_dummy); 1760 1761 #ifdef CONFIG_I2C_COMPAT 1762 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, 1763 adap->dev.parent); 1764 #endif 1765 1766 /* device name is gone after device_unregister */ 1767 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); 1768 1769 pm_runtime_disable(&adap->dev); 1770 1771 i2c_host_notify_irq_teardown(adap); 1772 1773 debugfs_remove_recursive(adap->debugfs); 1774 1775 /* wait until all references to the device are gone 1776 * 1777 * FIXME: This is old code and should ideally be replaced by an 1778 * alternative which results in decoupling the lifetime of the struct 1779 * device from the i2c_adapter, like spi or netdev do. Any solution 1780 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled! 1781 */ 1782 init_completion(&adap->dev_released); 1783 device_unregister(&adap->dev); 1784 wait_for_completion(&adap->dev_released); 1785 1786 /* free bus id */ 1787 mutex_lock(&core_lock); 1788 idr_remove(&i2c_adapter_idr, adap->nr); 1789 mutex_unlock(&core_lock); 1790 1791 /* Clear the device structure in case this adapter is ever going to be 1792 added again */ 1793 memset(&adap->dev, 0, sizeof(adap->dev)); 1794 } 1795 EXPORT_SYMBOL(i2c_del_adapter); 1796 1797 static void devm_i2c_del_adapter(void *adapter) 1798 { 1799 i2c_del_adapter(adapter); 1800 } 1801 1802 /** 1803 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter() 1804 * @dev: managing device for adding this I2C adapter 1805 * @adapter: the adapter to add 1806 * Context: can sleep 1807 * 1808 * Add adapter with dynamic bus number, same with i2c_add_adapter() 1809 * but the adapter will be auto deleted on driver detach. 1810 */ 1811 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter) 1812 { 1813 int ret; 1814 1815 ret = i2c_add_adapter(adapter); 1816 if (ret) 1817 return ret; 1818 1819 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter); 1820 } 1821 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter); 1822 1823 static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data) 1824 { 1825 if (dev_fwnode(dev) == data) 1826 return 1; 1827 1828 if (dev->parent && dev_fwnode(dev->parent) == data) 1829 return 1; 1830 1831 return 0; 1832 } 1833 1834 /** 1835 * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode 1836 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter 1837 * 1838 * Look up and return the &struct i2c_adapter corresponding to the @fwnode. 1839 * If no adapter can be found, or @fwnode is NULL, this returns NULL. 1840 * 1841 * The user must call put_device(&adapter->dev) once done with the i2c adapter. 1842 */ 1843 struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode) 1844 { 1845 struct i2c_adapter *adapter; 1846 struct device *dev; 1847 1848 if (!fwnode) 1849 return NULL; 1850 1851 dev = bus_find_device(&i2c_bus_type, NULL, fwnode, 1852 i2c_dev_or_parent_fwnode_match); 1853 if (!dev) 1854 return NULL; 1855 1856 adapter = i2c_verify_adapter(dev); 1857 if (!adapter) 1858 put_device(dev); 1859 1860 return adapter; 1861 } 1862 EXPORT_SYMBOL(i2c_find_adapter_by_fwnode); 1863 1864 /** 1865 * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode 1866 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter 1867 * 1868 * Look up and return the &struct i2c_adapter corresponding to the @fwnode, 1869 * and increment the adapter module's use count. If no adapter can be found, 1870 * or @fwnode is NULL, this returns NULL. 1871 * 1872 * The user must call i2c_put_adapter(adapter) once done with the i2c adapter. 1873 * Note that this is different from i2c_find_adapter_by_node(). 1874 */ 1875 struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode) 1876 { 1877 struct i2c_adapter *adapter; 1878 1879 adapter = i2c_find_adapter_by_fwnode(fwnode); 1880 if (!adapter) 1881 return NULL; 1882 1883 if (!try_module_get(adapter->owner)) { 1884 put_device(&adapter->dev); 1885 adapter = NULL; 1886 } 1887 1888 return adapter; 1889 } 1890 EXPORT_SYMBOL(i2c_get_adapter_by_fwnode); 1891 1892 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p, 1893 u32 def_val, bool use_def) 1894 { 1895 int ret; 1896 1897 ret = device_property_read_u32(dev, prop_name, cur_val_p); 1898 if (ret && use_def) 1899 *cur_val_p = def_val; 1900 1901 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p); 1902 } 1903 1904 /** 1905 * i2c_parse_fw_timings - get I2C related timing parameters from firmware 1906 * @dev: The device to scan for I2C timing properties 1907 * @t: the i2c_timings struct to be filled with values 1908 * @use_defaults: bool to use sane defaults derived from the I2C specification 1909 * when properties are not found, otherwise don't update 1910 * 1911 * Scan the device for the generic I2C properties describing timing parameters 1912 * for the signal and fill the given struct with the results. If a property was 1913 * not found and use_defaults was true, then maximum timings are assumed which 1914 * are derived from the I2C specification. If use_defaults is not used, the 1915 * results will be as before, so drivers can apply their own defaults before 1916 * calling this helper. The latter is mainly intended for avoiding regressions 1917 * of existing drivers which want to switch to this function. New drivers 1918 * almost always should use the defaults. 1919 */ 1920 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults) 1921 { 1922 bool u = use_defaults; 1923 u32 d; 1924 1925 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz, 1926 I2C_MAX_STANDARD_MODE_FREQ, u); 1927 1928 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 : 1929 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1930 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u); 1931 1932 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120; 1933 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u); 1934 1935 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns", 1936 &t->scl_int_delay_ns, 0, u); 1937 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns, 1938 t->scl_fall_ns, u); 1939 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u); 1940 i2c_parse_timing(dev, "i2c-digital-filter-width-ns", 1941 &t->digital_filter_width_ns, 0, u); 1942 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency", 1943 &t->analog_filter_cutoff_freq_hz, 0, u); 1944 } 1945 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings); 1946 1947 /* ------------------------------------------------------------------------- */ 1948 1949 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data)) 1950 { 1951 int res; 1952 1953 mutex_lock(&core_lock); 1954 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn); 1955 mutex_unlock(&core_lock); 1956 1957 return res; 1958 } 1959 EXPORT_SYMBOL_GPL(i2c_for_each_dev); 1960 1961 static int __process_new_driver(struct device *dev, void *data) 1962 { 1963 if (dev->type != &i2c_adapter_type) 1964 return 0; 1965 return i2c_do_add_adapter(data, to_i2c_adapter(dev)); 1966 } 1967 1968 /* 1969 * An i2c_driver is used with one or more i2c_client (device) nodes to access 1970 * i2c slave chips, on a bus instance associated with some i2c_adapter. 1971 */ 1972 1973 int i2c_register_driver(struct module *owner, struct i2c_driver *driver) 1974 { 1975 int res; 1976 1977 /* Can't register until after driver model init */ 1978 if (WARN_ON(!is_registered)) 1979 return -EAGAIN; 1980 1981 /* add the driver to the list of i2c drivers in the driver core */ 1982 driver->driver.owner = owner; 1983 driver->driver.bus = &i2c_bus_type; 1984 INIT_LIST_HEAD(&driver->clients); 1985 1986 /* When registration returns, the driver core 1987 * will have called probe() for all matching-but-unbound devices. 1988 */ 1989 res = driver_register(&driver->driver); 1990 if (res) 1991 return res; 1992 1993 pr_debug("driver [%s] registered\n", driver->driver.name); 1994 1995 /* Walk the adapters that are already present */ 1996 i2c_for_each_dev(driver, __process_new_driver); 1997 1998 return 0; 1999 } 2000 EXPORT_SYMBOL(i2c_register_driver); 2001 2002 static int __process_removed_driver(struct device *dev, void *data) 2003 { 2004 if (dev->type == &i2c_adapter_type) 2005 i2c_do_del_adapter(data, to_i2c_adapter(dev)); 2006 return 0; 2007 } 2008 2009 /** 2010 * i2c_del_driver - unregister I2C driver 2011 * @driver: the driver being unregistered 2012 * Context: can sleep 2013 */ 2014 void i2c_del_driver(struct i2c_driver *driver) 2015 { 2016 i2c_for_each_dev(driver, __process_removed_driver); 2017 2018 driver_unregister(&driver->driver); 2019 pr_debug("driver [%s] unregistered\n", driver->driver.name); 2020 } 2021 EXPORT_SYMBOL(i2c_del_driver); 2022 2023 /* ------------------------------------------------------------------------- */ 2024 2025 struct i2c_cmd_arg { 2026 unsigned cmd; 2027 void *arg; 2028 }; 2029 2030 static int i2c_cmd(struct device *dev, void *_arg) 2031 { 2032 struct i2c_client *client = i2c_verify_client(dev); 2033 struct i2c_cmd_arg *arg = _arg; 2034 struct i2c_driver *driver; 2035 2036 if (!client || !client->dev.driver) 2037 return 0; 2038 2039 driver = to_i2c_driver(client->dev.driver); 2040 if (driver->command) 2041 driver->command(client, arg->cmd, arg->arg); 2042 return 0; 2043 } 2044 2045 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) 2046 { 2047 struct i2c_cmd_arg cmd_arg; 2048 2049 cmd_arg.cmd = cmd; 2050 cmd_arg.arg = arg; 2051 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); 2052 } 2053 EXPORT_SYMBOL(i2c_clients_command); 2054 2055 static int __init i2c_init(void) 2056 { 2057 int retval; 2058 2059 retval = of_alias_get_highest_id("i2c"); 2060 2061 down_write(&__i2c_board_lock); 2062 if (retval >= __i2c_first_dynamic_bus_num) 2063 __i2c_first_dynamic_bus_num = retval + 1; 2064 up_write(&__i2c_board_lock); 2065 2066 retval = bus_register(&i2c_bus_type); 2067 if (retval) 2068 return retval; 2069 2070 is_registered = true; 2071 2072 i2c_debugfs_root = debugfs_create_dir("i2c", NULL); 2073 2074 #ifdef CONFIG_I2C_COMPAT 2075 i2c_adapter_compat_class = class_compat_register("i2c-adapter"); 2076 if (!i2c_adapter_compat_class) { 2077 retval = -ENOMEM; 2078 goto bus_err; 2079 } 2080 #endif 2081 retval = i2c_add_driver(&dummy_driver); 2082 if (retval) 2083 goto class_err; 2084 2085 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 2086 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); 2087 if (IS_ENABLED(CONFIG_ACPI)) 2088 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier)); 2089 2090 return 0; 2091 2092 class_err: 2093 #ifdef CONFIG_I2C_COMPAT 2094 class_compat_unregister(i2c_adapter_compat_class); 2095 bus_err: 2096 #endif 2097 is_registered = false; 2098 bus_unregister(&i2c_bus_type); 2099 return retval; 2100 } 2101 2102 static void __exit i2c_exit(void) 2103 { 2104 if (IS_ENABLED(CONFIG_ACPI)) 2105 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier)); 2106 if (IS_ENABLED(CONFIG_OF_DYNAMIC)) 2107 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier)); 2108 i2c_del_driver(&dummy_driver); 2109 #ifdef CONFIG_I2C_COMPAT 2110 class_compat_unregister(i2c_adapter_compat_class); 2111 #endif 2112 debugfs_remove_recursive(i2c_debugfs_root); 2113 bus_unregister(&i2c_bus_type); 2114 tracepoint_synchronize_unregister(); 2115 } 2116 2117 /* We must initialize early, because some subsystems register i2c drivers 2118 * in subsys_initcall() code, but are linked (and initialized) before i2c. 2119 */ 2120 postcore_initcall(i2c_init); 2121 module_exit(i2c_exit); 2122 2123 /* ---------------------------------------------------- 2124 * the functional interface to the i2c busses. 2125 * ---------------------------------------------------- 2126 */ 2127 2128 /* Check if val is exceeding the quirk IFF quirk is non 0 */ 2129 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) 2130 2131 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) 2132 { 2133 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n", 2134 err_msg, msg->addr, msg->len, 2135 msg->flags & I2C_M_RD ? "read" : "write"); 2136 return -EOPNOTSUPP; 2137 } 2138 2139 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2140 { 2141 const struct i2c_adapter_quirks *q = adap->quirks; 2142 int max_num = q->max_num_msgs, i; 2143 bool do_len_check = true; 2144 2145 if (q->flags & I2C_AQ_COMB) { 2146 max_num = 2; 2147 2148 /* special checks for combined messages */ 2149 if (num == 2) { 2150 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD) 2151 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write"); 2152 2153 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD)) 2154 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read"); 2155 2156 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr) 2157 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr"); 2158 2159 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len)) 2160 return i2c_quirk_error(adap, &msgs[0], "msg too long"); 2161 2162 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len)) 2163 return i2c_quirk_error(adap, &msgs[1], "msg too long"); 2164 2165 do_len_check = false; 2166 } 2167 } 2168 2169 if (i2c_quirk_exceeded(num, max_num)) 2170 return i2c_quirk_error(adap, &msgs[0], "too many messages"); 2171 2172 for (i = 0; i < num; i++) { 2173 u16 len = msgs[i].len; 2174 2175 if (msgs[i].flags & I2C_M_RD) { 2176 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len)) 2177 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2178 2179 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0) 2180 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2181 } else { 2182 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len)) 2183 return i2c_quirk_error(adap, &msgs[i], "msg too long"); 2184 2185 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0) 2186 return i2c_quirk_error(adap, &msgs[i], "no zero length"); 2187 } 2188 } 2189 2190 return 0; 2191 } 2192 2193 /** 2194 * __i2c_transfer - unlocked flavor of i2c_transfer 2195 * @adap: Handle to I2C bus 2196 * @msgs: One or more messages to execute before STOP is issued to 2197 * terminate the operation; each message begins with a START. 2198 * @num: Number of messages to be executed. 2199 * 2200 * Returns negative errno, else the number of messages executed. 2201 * 2202 * Adapter lock must be held when calling this function. No debug logging 2203 * takes place. adap->algo->master_xfer existence isn't checked. 2204 */ 2205 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2206 { 2207 unsigned long orig_jiffies; 2208 int ret, try; 2209 2210 if (WARN_ON(!msgs || num < 1)) 2211 return -EINVAL; 2212 2213 ret = __i2c_check_suspended(adap); 2214 if (ret) 2215 return ret; 2216 2217 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) 2218 return -EOPNOTSUPP; 2219 2220 /* 2221 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets 2222 * enabled. This is an efficient way of keeping the for-loop from 2223 * being executed when not needed. 2224 */ 2225 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2226 int i; 2227 for (i = 0; i < num; i++) 2228 if (msgs[i].flags & I2C_M_RD) 2229 trace_i2c_read(adap, &msgs[i], i); 2230 else 2231 trace_i2c_write(adap, &msgs[i], i); 2232 } 2233 2234 /* Retry automatically on arbitration loss */ 2235 orig_jiffies = jiffies; 2236 for (ret = 0, try = 0; try <= adap->retries; try++) { 2237 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic) 2238 ret = adap->algo->master_xfer_atomic(adap, msgs, num); 2239 else 2240 ret = adap->algo->master_xfer(adap, msgs, num); 2241 2242 if (ret != -EAGAIN) 2243 break; 2244 if (time_after(jiffies, orig_jiffies + adap->timeout)) 2245 break; 2246 } 2247 2248 if (static_branch_unlikely(&i2c_trace_msg_key)) { 2249 int i; 2250 for (i = 0; i < ret; i++) 2251 if (msgs[i].flags & I2C_M_RD) 2252 trace_i2c_reply(adap, &msgs[i], i); 2253 trace_i2c_result(adap, num, ret); 2254 } 2255 2256 return ret; 2257 } 2258 EXPORT_SYMBOL(__i2c_transfer); 2259 2260 /** 2261 * i2c_transfer - execute a single or combined I2C message 2262 * @adap: Handle to I2C bus 2263 * @msgs: One or more messages to execute before STOP is issued to 2264 * terminate the operation; each message begins with a START. 2265 * @num: Number of messages to be executed. 2266 * 2267 * Returns negative errno, else the number of messages executed. 2268 * 2269 * Note that there is no requirement that each message be sent to 2270 * the same slave address, although that is the most common model. 2271 */ 2272 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 2273 { 2274 int ret; 2275 2276 if (!adap->algo->master_xfer) { 2277 dev_dbg(&adap->dev, "I2C level transfers not supported\n"); 2278 return -EOPNOTSUPP; 2279 } 2280 2281 /* REVISIT the fault reporting model here is weak: 2282 * 2283 * - When we get an error after receiving N bytes from a slave, 2284 * there is no way to report "N". 2285 * 2286 * - When we get a NAK after transmitting N bytes to a slave, 2287 * there is no way to report "N" ... or to let the master 2288 * continue executing the rest of this combined message, if 2289 * that's the appropriate response. 2290 * 2291 * - When for example "num" is two and we successfully complete 2292 * the first message but get an error part way through the 2293 * second, it's unclear whether that should be reported as 2294 * one (discarding status on the second message) or errno 2295 * (discarding status on the first one). 2296 */ 2297 ret = __i2c_lock_bus_helper(adap); 2298 if (ret) 2299 return ret; 2300 2301 ret = __i2c_transfer(adap, msgs, num); 2302 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT); 2303 2304 return ret; 2305 } 2306 EXPORT_SYMBOL(i2c_transfer); 2307 2308 /** 2309 * i2c_transfer_buffer_flags - issue a single I2C message transferring data 2310 * to/from a buffer 2311 * @client: Handle to slave device 2312 * @buf: Where the data is stored 2313 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16 2314 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads 2315 * 2316 * Returns negative errno, or else the number of bytes transferred. 2317 */ 2318 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf, 2319 int count, u16 flags) 2320 { 2321 int ret; 2322 struct i2c_msg msg = { 2323 .addr = client->addr, 2324 .flags = flags | (client->flags & I2C_M_TEN), 2325 .len = count, 2326 .buf = buf, 2327 }; 2328 2329 ret = i2c_transfer(client->adapter, &msg, 1); 2330 2331 /* 2332 * If everything went ok (i.e. 1 msg transferred), return #bytes 2333 * transferred, else error code. 2334 */ 2335 return (ret == 1) ? count : ret; 2336 } 2337 EXPORT_SYMBOL(i2c_transfer_buffer_flags); 2338 2339 /** 2340 * i2c_get_device_id - get manufacturer, part id and die revision of a device 2341 * @client: The device to query 2342 * @id: The queried information 2343 * 2344 * Returns negative errno on error, zero on success. 2345 */ 2346 int i2c_get_device_id(const struct i2c_client *client, 2347 struct i2c_device_identity *id) 2348 { 2349 struct i2c_adapter *adap = client->adapter; 2350 union i2c_smbus_data raw_id; 2351 int ret; 2352 2353 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) 2354 return -EOPNOTSUPP; 2355 2356 raw_id.block[0] = 3; 2357 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0, 2358 I2C_SMBUS_READ, client->addr << 1, 2359 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id); 2360 if (ret) 2361 return ret; 2362 2363 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4); 2364 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3); 2365 id->die_revision = raw_id.block[3] & 0x7; 2366 return 0; 2367 } 2368 EXPORT_SYMBOL_GPL(i2c_get_device_id); 2369 2370 /** 2371 * i2c_client_get_device_id - get the driver match table entry of a device 2372 * @client: the device to query. The device must be bound to a driver 2373 * 2374 * Returns a pointer to the matching entry if found, NULL otherwise. 2375 */ 2376 const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client) 2377 { 2378 const struct i2c_driver *drv = to_i2c_driver(client->dev.driver); 2379 2380 return i2c_match_id(drv->id_table, client); 2381 } 2382 EXPORT_SYMBOL_GPL(i2c_client_get_device_id); 2383 2384 /* ---------------------------------------------------- 2385 * the i2c address scanning function 2386 * Will not work for 10-bit addresses! 2387 * ---------------------------------------------------- 2388 */ 2389 2390 /* 2391 * Legacy default probe function, mostly relevant for SMBus. The default 2392 * probe method is a quick write, but it is known to corrupt the 24RF08 2393 * EEPROMs due to a state machine bug, and could also irreversibly 2394 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f, 2395 * we use a short byte read instead. Also, some bus drivers don't implement 2396 * quick write, so we fallback to a byte read in that case too. 2397 * On x86, there is another special case for FSC hardware monitoring chips, 2398 * which want regular byte reads (address 0x73.) Fortunately, these are the 2399 * only known chips using this I2C address on PC hardware. 2400 * Returns 1 if probe succeeded, 0 if not. 2401 */ 2402 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) 2403 { 2404 int err; 2405 union i2c_smbus_data dummy; 2406 2407 #ifdef CONFIG_X86 2408 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON) 2409 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA)) 2410 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2411 I2C_SMBUS_BYTE_DATA, &dummy); 2412 else 2413 #endif 2414 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) 2415 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) 2416 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, 2417 I2C_SMBUS_QUICK, NULL); 2418 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) 2419 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2420 I2C_SMBUS_BYTE, &dummy); 2421 else { 2422 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n", 2423 addr); 2424 err = -EOPNOTSUPP; 2425 } 2426 2427 return err >= 0; 2428 } 2429 2430 static int i2c_detect_address(struct i2c_client *temp_client, 2431 struct i2c_driver *driver) 2432 { 2433 struct i2c_board_info info; 2434 struct i2c_adapter *adapter = temp_client->adapter; 2435 int addr = temp_client->addr; 2436 int err; 2437 2438 /* Make sure the address is valid */ 2439 err = i2c_check_7bit_addr_validity_strict(addr); 2440 if (err) { 2441 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n", 2442 addr); 2443 return err; 2444 } 2445 2446 /* Skip if already in use (7 bit, no need to encode flags) */ 2447 if (i2c_check_addr_busy(adapter, addr)) 2448 return 0; 2449 2450 /* Make sure there is something at this address */ 2451 if (!i2c_default_probe(adapter, addr)) 2452 return 0; 2453 2454 /* Finally call the custom detection function */ 2455 memset(&info, 0, sizeof(struct i2c_board_info)); 2456 info.addr = addr; 2457 err = driver->detect(temp_client, &info); 2458 if (err) { 2459 /* -ENODEV is returned if the detection fails. We catch it 2460 here as this isn't an error. */ 2461 return err == -ENODEV ? 0 : err; 2462 } 2463 2464 /* Consistency check */ 2465 if (info.type[0] == '\0') { 2466 dev_err(&adapter->dev, 2467 "%s detection function provided no name for 0x%x\n", 2468 driver->driver.name, addr); 2469 } else { 2470 struct i2c_client *client; 2471 2472 /* Detection succeeded, instantiate the device */ 2473 if (adapter->class & I2C_CLASS_DEPRECATED) 2474 dev_warn(&adapter->dev, 2475 "This adapter will soon drop class based instantiation of devices. " 2476 "Please make sure client 0x%02x gets instantiated by other means. " 2477 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n", 2478 info.addr); 2479 2480 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n", 2481 info.type, info.addr); 2482 client = i2c_new_client_device(adapter, &info); 2483 if (!IS_ERR(client)) 2484 list_add_tail(&client->detected, &driver->clients); 2485 else 2486 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n", 2487 info.type, info.addr); 2488 } 2489 return 0; 2490 } 2491 2492 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) 2493 { 2494 const unsigned short *address_list; 2495 struct i2c_client *temp_client; 2496 int i, err = 0; 2497 2498 address_list = driver->address_list; 2499 if (!driver->detect || !address_list) 2500 return 0; 2501 2502 /* Warn that the adapter lost class based instantiation */ 2503 if (adapter->class == I2C_CLASS_DEPRECATED) { 2504 dev_dbg(&adapter->dev, 2505 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. " 2506 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n", 2507 driver->driver.name); 2508 return 0; 2509 } 2510 2511 /* Stop here if the classes do not match */ 2512 if (!(adapter->class & driver->class)) 2513 return 0; 2514 2515 /* Set up a temporary client to help detect callback */ 2516 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); 2517 if (!temp_client) 2518 return -ENOMEM; 2519 temp_client->adapter = adapter; 2520 2521 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { 2522 dev_dbg(&adapter->dev, 2523 "found normal entry for adapter %d, addr 0x%02x\n", 2524 i2c_adapter_id(adapter), address_list[i]); 2525 temp_client->addr = address_list[i]; 2526 err = i2c_detect_address(temp_client, driver); 2527 if (unlikely(err)) 2528 break; 2529 } 2530 2531 kfree(temp_client); 2532 return err; 2533 } 2534 2535 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) 2536 { 2537 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 2538 I2C_SMBUS_QUICK, NULL) >= 0; 2539 } 2540 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); 2541 2542 struct i2c_client * 2543 i2c_new_scanned_device(struct i2c_adapter *adap, 2544 struct i2c_board_info *info, 2545 unsigned short const *addr_list, 2546 int (*probe)(struct i2c_adapter *adap, unsigned short addr)) 2547 { 2548 int i; 2549 2550 if (!probe) 2551 probe = i2c_default_probe; 2552 2553 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { 2554 /* Check address validity */ 2555 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) { 2556 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n", 2557 addr_list[i]); 2558 continue; 2559 } 2560 2561 /* Check address availability (7 bit, no need to encode flags) */ 2562 if (i2c_check_addr_busy(adap, addr_list[i])) { 2563 dev_dbg(&adap->dev, 2564 "Address 0x%02x already in use, not probing\n", 2565 addr_list[i]); 2566 continue; 2567 } 2568 2569 /* Test address responsiveness */ 2570 if (probe(adap, addr_list[i])) 2571 break; 2572 } 2573 2574 if (addr_list[i] == I2C_CLIENT_END) { 2575 dev_dbg(&adap->dev, "Probing failed, no device found\n"); 2576 return ERR_PTR(-ENODEV); 2577 } 2578 2579 info->addr = addr_list[i]; 2580 return i2c_new_client_device(adap, info); 2581 } 2582 EXPORT_SYMBOL_GPL(i2c_new_scanned_device); 2583 2584 struct i2c_adapter *i2c_get_adapter(int nr) 2585 { 2586 struct i2c_adapter *adapter; 2587 2588 mutex_lock(&core_lock); 2589 adapter = idr_find(&i2c_adapter_idr, nr); 2590 if (!adapter) 2591 goto exit; 2592 2593 if (try_module_get(adapter->owner)) 2594 get_device(&adapter->dev); 2595 else 2596 adapter = NULL; 2597 2598 exit: 2599 mutex_unlock(&core_lock); 2600 return adapter; 2601 } 2602 EXPORT_SYMBOL(i2c_get_adapter); 2603 2604 void i2c_put_adapter(struct i2c_adapter *adap) 2605 { 2606 if (!adap) 2607 return; 2608 2609 module_put(adap->owner); 2610 /* Should be last, otherwise we risk use-after-free with 'adap' */ 2611 put_device(&adap->dev); 2612 } 2613 EXPORT_SYMBOL(i2c_put_adapter); 2614 2615 /** 2616 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg 2617 * @msg: the message to be checked 2618 * @threshold: the minimum number of bytes for which using DMA makes sense. 2619 * Should at least be 1. 2620 * 2621 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO. 2622 * Or a valid pointer to be used with DMA. After use, release it by 2623 * calling i2c_put_dma_safe_msg_buf(). 2624 * 2625 * This function must only be called from process context! 2626 */ 2627 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold) 2628 { 2629 /* also skip 0-length msgs for bogus thresholds of 0 */ 2630 if (!threshold) 2631 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n", 2632 msg->addr); 2633 if (msg->len < threshold || msg->len == 0) 2634 return NULL; 2635 2636 if (msg->flags & I2C_M_DMA_SAFE) 2637 return msg->buf; 2638 2639 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n", 2640 msg->addr, msg->len); 2641 2642 if (msg->flags & I2C_M_RD) 2643 return kzalloc(msg->len, GFP_KERNEL); 2644 else 2645 return kmemdup(msg->buf, msg->len, GFP_KERNEL); 2646 } 2647 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf); 2648 2649 /** 2650 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg 2651 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL. 2652 * @msg: the message which the buffer corresponds to 2653 * @xferred: bool saying if the message was transferred 2654 */ 2655 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred) 2656 { 2657 if (!buf || buf == msg->buf) 2658 return; 2659 2660 if (xferred && msg->flags & I2C_M_RD) 2661 memcpy(msg->buf, buf, msg->len); 2662 2663 kfree(buf); 2664 } 2665 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf); 2666 2667 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 2668 MODULE_DESCRIPTION("I2C-Bus main module"); 2669 MODULE_LICENSE("GPL"); 2670