/drivers/i2c/i2c-core.c
C | 3409 lines | 2286 code | 523 blank | 600 comment | 439 complexity | d25163411f21d600ab4a7d548aa78732 MD5 | raw file
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1/* i2c-core.c - a device driver for the iic-bus interface */ 2/* ------------------------------------------------------------------------- */ 3/* Copyright (C) 1995-99 Simon G. Vogl 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. */ 14/* ------------------------------------------------------------------------- */ 15 16/* With some changes from KyĂśsti Mälkki <kmalkki@cc.hut.fi>. 17 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl> 18 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and 19 Jean Delvare <jdelvare@suse.de> 20 Mux support by Rodolfo Giometti <giometti@enneenne.com> and 21 Michael Lawnick <michael.lawnick.ext@nsn.com> 22 OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de> 23 (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and 24 (c) 2013 Wolfram Sang <wsa@the-dreams.de> 25 I2C ACPI code Copyright (C) 2014 Intel Corp 26 Author: Lan Tianyu <tianyu.lan@intel.com> 27 I2C slave support (c) 2014 by Wolfram Sang <wsa@sang-engineering.com> 28 */ 29 30#define pr_fmt(fmt) "i2c-core: " fmt 31 32#include <dt-bindings/i2c/i2c.h> 33#include <asm/uaccess.h> 34#include <linux/acpi.h> 35#include <linux/clk/clk-conf.h> 36#include <linux/completion.h> 37#include <linux/delay.h> 38#include <linux/err.h> 39#include <linux/errno.h> 40#include <linux/gpio.h> 41#include <linux/hardirq.h> 42#include <linux/i2c.h> 43#include <linux/idr.h> 44#include <linux/init.h> 45#include <linux/irqflags.h> 46#include <linux/jump_label.h> 47#include <linux/kernel.h> 48#include <linux/module.h> 49#include <linux/mutex.h> 50#include <linux/of_device.h> 51#include <linux/of.h> 52#include <linux/of_irq.h> 53#include <linux/pm_domain.h> 54#include <linux/pm_runtime.h> 55#include <linux/pm_wakeirq.h> 56#include <linux/property.h> 57#include <linux/rwsem.h> 58#include <linux/slab.h> 59 60#include "i2c-core.h" 61 62#define CREATE_TRACE_POINTS 63#include <trace/events/i2c.h> 64 65#define I2C_ADDR_OFFSET_TEN_BIT 0xa000 66#define I2C_ADDR_OFFSET_SLAVE 0x1000 67 68/* core_lock protects i2c_adapter_idr, and guarantees 69 that device detection, deletion of detected devices, and attach_adapter 70 calls are serialized */ 71static DEFINE_MUTEX(core_lock); 72static DEFINE_IDR(i2c_adapter_idr); 73 74static struct device_type i2c_client_type; 75static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); 76 77static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE; 78static bool is_registered; 79 80void i2c_transfer_trace_reg(void) 81{ 82 static_key_slow_inc(&i2c_trace_msg); 83} 84 85void i2c_transfer_trace_unreg(void) 86{ 87 static_key_slow_dec(&i2c_trace_msg); 88} 89 90#if defined(CONFIG_ACPI) 91struct acpi_i2c_handler_data { 92 struct acpi_connection_info info; 93 struct i2c_adapter *adapter; 94}; 95 96struct gsb_buffer { 97 u8 status; 98 u8 len; 99 union { 100 u16 wdata; 101 u8 bdata; 102 u8 data[0]; 103 }; 104} __packed; 105 106struct acpi_i2c_lookup { 107 struct i2c_board_info *info; 108 acpi_handle adapter_handle; 109 acpi_handle device_handle; 110}; 111 112static int acpi_i2c_fill_info(struct acpi_resource *ares, void *data) 113{ 114 struct acpi_i2c_lookup *lookup = data; 115 struct i2c_board_info *info = lookup->info; 116 struct acpi_resource_i2c_serialbus *sb; 117 acpi_status status; 118 119 if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) 120 return 1; 121 122 sb = &ares->data.i2c_serial_bus; 123 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) 124 return 1; 125 126 status = acpi_get_handle(lookup->device_handle, 127 sb->resource_source.string_ptr, 128 &lookup->adapter_handle); 129 if (!ACPI_SUCCESS(status)) 130 return 1; 131 132 info->addr = sb->slave_address; 133 if (sb->access_mode == ACPI_I2C_10BIT_MODE) 134 info->flags |= I2C_CLIENT_TEN; 135 136 return 1; 137} 138 139static int acpi_i2c_get_info(struct acpi_device *adev, 140 struct i2c_board_info *info, 141 acpi_handle *adapter_handle) 142{ 143 struct list_head resource_list; 144 struct resource_entry *entry; 145 struct acpi_i2c_lookup lookup; 146 int ret; 147 148 if (acpi_bus_get_status(adev) || !adev->status.present || 149 acpi_device_enumerated(adev)) 150 return -EINVAL; 151 152 memset(info, 0, sizeof(*info)); 153 info->fwnode = acpi_fwnode_handle(adev); 154 155 memset(&lookup, 0, sizeof(lookup)); 156 lookup.device_handle = acpi_device_handle(adev); 157 lookup.info = info; 158 159 /* Look up for I2cSerialBus resource */ 160 INIT_LIST_HEAD(&resource_list); 161 ret = acpi_dev_get_resources(adev, &resource_list, 162 acpi_i2c_fill_info, &lookup); 163 acpi_dev_free_resource_list(&resource_list); 164 165 if (ret < 0 || !info->addr) 166 return -EINVAL; 167 168 *adapter_handle = lookup.adapter_handle; 169 170 /* Then fill IRQ number if any */ 171 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL); 172 if (ret < 0) 173 return -EINVAL; 174 175 resource_list_for_each_entry(entry, &resource_list) { 176 if (resource_type(entry->res) == IORESOURCE_IRQ) { 177 info->irq = entry->res->start; 178 break; 179 } 180 } 181 182 acpi_dev_free_resource_list(&resource_list); 183 184 strlcpy(info->type, dev_name(&adev->dev), sizeof(info->type)); 185 186 return 0; 187} 188 189static void acpi_i2c_register_device(struct i2c_adapter *adapter, 190 struct acpi_device *adev, 191 struct i2c_board_info *info) 192{ 193 adev->power.flags.ignore_parent = true; 194 acpi_device_set_enumerated(adev); 195 196 if (!i2c_new_device(adapter, info)) { 197 adev->power.flags.ignore_parent = false; 198 dev_err(&adapter->dev, 199 "failed to add I2C device %s from ACPI\n", 200 dev_name(&adev->dev)); 201 } 202} 203 204static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level, 205 void *data, void **return_value) 206{ 207 struct i2c_adapter *adapter = data; 208 struct acpi_device *adev; 209 acpi_handle adapter_handle; 210 struct i2c_board_info info; 211 212 if (acpi_bus_get_device(handle, &adev)) 213 return AE_OK; 214 215 if (acpi_i2c_get_info(adev, &info, &adapter_handle)) 216 return AE_OK; 217 218 if (adapter_handle != ACPI_HANDLE(&adapter->dev)) 219 return AE_OK; 220 221 acpi_i2c_register_device(adapter, adev, &info); 222 223 return AE_OK; 224} 225 226#define ACPI_I2C_MAX_SCAN_DEPTH 32 227 228/** 229 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter 230 * @adap: pointer to adapter 231 * 232 * Enumerate all I2C slave devices behind this adapter by walking the ACPI 233 * namespace. When a device is found it will be added to the Linux device 234 * model and bound to the corresponding ACPI handle. 235 */ 236static void acpi_i2c_register_devices(struct i2c_adapter *adap) 237{ 238 acpi_status status; 239 240 if (!has_acpi_companion(&adap->dev)) 241 return; 242 243 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 244 ACPI_I2C_MAX_SCAN_DEPTH, 245 acpi_i2c_add_device, NULL, 246 adap, NULL); 247 if (ACPI_FAILURE(status)) 248 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n"); 249} 250 251static int acpi_i2c_match_adapter(struct device *dev, void *data) 252{ 253 struct i2c_adapter *adapter = i2c_verify_adapter(dev); 254 255 if (!adapter) 256 return 0; 257 258 return ACPI_HANDLE(dev) == (acpi_handle)data; 259} 260 261static int acpi_i2c_match_device(struct device *dev, void *data) 262{ 263 return ACPI_COMPANION(dev) == data; 264} 265 266static struct i2c_adapter *acpi_i2c_find_adapter_by_handle(acpi_handle handle) 267{ 268 struct device *dev; 269 270 dev = bus_find_device(&i2c_bus_type, NULL, handle, 271 acpi_i2c_match_adapter); 272 return dev ? i2c_verify_adapter(dev) : NULL; 273} 274 275static struct i2c_client *acpi_i2c_find_client_by_adev(struct acpi_device *adev) 276{ 277 struct device *dev; 278 279 dev = bus_find_device(&i2c_bus_type, NULL, adev, acpi_i2c_match_device); 280 return dev ? i2c_verify_client(dev) : NULL; 281} 282 283static int acpi_i2c_notify(struct notifier_block *nb, unsigned long value, 284 void *arg) 285{ 286 struct acpi_device *adev = arg; 287 struct i2c_board_info info; 288 acpi_handle adapter_handle; 289 struct i2c_adapter *adapter; 290 struct i2c_client *client; 291 292 switch (value) { 293 case ACPI_RECONFIG_DEVICE_ADD: 294 if (acpi_i2c_get_info(adev, &info, &adapter_handle)) 295 break; 296 297 adapter = acpi_i2c_find_adapter_by_handle(adapter_handle); 298 if (!adapter) 299 break; 300 301 acpi_i2c_register_device(adapter, adev, &info); 302 break; 303 case ACPI_RECONFIG_DEVICE_REMOVE: 304 if (!acpi_device_enumerated(adev)) 305 break; 306 307 client = acpi_i2c_find_client_by_adev(adev); 308 if (!client) 309 break; 310 311 i2c_unregister_device(client); 312 put_device(&client->dev); 313 break; 314 } 315 316 return NOTIFY_OK; 317} 318 319static struct notifier_block i2c_acpi_notifier = { 320 .notifier_call = acpi_i2c_notify, 321}; 322#else /* CONFIG_ACPI */ 323static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) { } 324extern struct notifier_block i2c_acpi_notifier; 325#endif /* CONFIG_ACPI */ 326 327#ifdef CONFIG_ACPI_I2C_OPREGION 328static int acpi_gsb_i2c_read_bytes(struct i2c_client *client, 329 u8 cmd, u8 *data, u8 data_len) 330{ 331 332 struct i2c_msg msgs[2]; 333 int ret; 334 u8 *buffer; 335 336 buffer = kzalloc(data_len, GFP_KERNEL); 337 if (!buffer) 338 return AE_NO_MEMORY; 339 340 msgs[0].addr = client->addr; 341 msgs[0].flags = client->flags; 342 msgs[0].len = 1; 343 msgs[0].buf = &cmd; 344 345 msgs[1].addr = client->addr; 346 msgs[1].flags = client->flags | I2C_M_RD; 347 msgs[1].len = data_len; 348 msgs[1].buf = buffer; 349 350 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 351 if (ret < 0) 352 dev_err(&client->adapter->dev, "i2c read failed\n"); 353 else 354 memcpy(data, buffer, data_len); 355 356 kfree(buffer); 357 return ret; 358} 359 360static int acpi_gsb_i2c_write_bytes(struct i2c_client *client, 361 u8 cmd, u8 *data, u8 data_len) 362{ 363 364 struct i2c_msg msgs[1]; 365 u8 *buffer; 366 int ret = AE_OK; 367 368 buffer = kzalloc(data_len + 1, GFP_KERNEL); 369 if (!buffer) 370 return AE_NO_MEMORY; 371 372 buffer[0] = cmd; 373 memcpy(buffer + 1, data, data_len); 374 375 msgs[0].addr = client->addr; 376 msgs[0].flags = client->flags; 377 msgs[0].len = data_len + 1; 378 msgs[0].buf = buffer; 379 380 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 381 if (ret < 0) 382 dev_err(&client->adapter->dev, "i2c write failed\n"); 383 384 kfree(buffer); 385 return ret; 386} 387 388static acpi_status 389acpi_i2c_space_handler(u32 function, acpi_physical_address command, 390 u32 bits, u64 *value64, 391 void *handler_context, void *region_context) 392{ 393 struct gsb_buffer *gsb = (struct gsb_buffer *)value64; 394 struct acpi_i2c_handler_data *data = handler_context; 395 struct acpi_connection_info *info = &data->info; 396 struct acpi_resource_i2c_serialbus *sb; 397 struct i2c_adapter *adapter = data->adapter; 398 struct i2c_client *client; 399 struct acpi_resource *ares; 400 u32 accessor_type = function >> 16; 401 u8 action = function & ACPI_IO_MASK; 402 acpi_status ret; 403 int status; 404 405 ret = acpi_buffer_to_resource(info->connection, info->length, &ares); 406 if (ACPI_FAILURE(ret)) 407 return ret; 408 409 client = kzalloc(sizeof(*client), GFP_KERNEL); 410 if (!client) { 411 ret = AE_NO_MEMORY; 412 goto err; 413 } 414 415 if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) { 416 ret = AE_BAD_PARAMETER; 417 goto err; 418 } 419 420 sb = &ares->data.i2c_serial_bus; 421 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) { 422 ret = AE_BAD_PARAMETER; 423 goto err; 424 } 425 426 client->adapter = adapter; 427 client->addr = sb->slave_address; 428 429 if (sb->access_mode == ACPI_I2C_10BIT_MODE) 430 client->flags |= I2C_CLIENT_TEN; 431 432 switch (accessor_type) { 433 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV: 434 if (action == ACPI_READ) { 435 status = i2c_smbus_read_byte(client); 436 if (status >= 0) { 437 gsb->bdata = status; 438 status = 0; 439 } 440 } else { 441 status = i2c_smbus_write_byte(client, gsb->bdata); 442 } 443 break; 444 445 case ACPI_GSB_ACCESS_ATTRIB_BYTE: 446 if (action == ACPI_READ) { 447 status = i2c_smbus_read_byte_data(client, command); 448 if (status >= 0) { 449 gsb->bdata = status; 450 status = 0; 451 } 452 } else { 453 status = i2c_smbus_write_byte_data(client, command, 454 gsb->bdata); 455 } 456 break; 457 458 case ACPI_GSB_ACCESS_ATTRIB_WORD: 459 if (action == ACPI_READ) { 460 status = i2c_smbus_read_word_data(client, command); 461 if (status >= 0) { 462 gsb->wdata = status; 463 status = 0; 464 } 465 } else { 466 status = i2c_smbus_write_word_data(client, command, 467 gsb->wdata); 468 } 469 break; 470 471 case ACPI_GSB_ACCESS_ATTRIB_BLOCK: 472 if (action == ACPI_READ) { 473 status = i2c_smbus_read_block_data(client, command, 474 gsb->data); 475 if (status >= 0) { 476 gsb->len = status; 477 status = 0; 478 } 479 } else { 480 status = i2c_smbus_write_block_data(client, command, 481 gsb->len, gsb->data); 482 } 483 break; 484 485 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE: 486 if (action == ACPI_READ) { 487 status = acpi_gsb_i2c_read_bytes(client, command, 488 gsb->data, info->access_length); 489 if (status > 0) 490 status = 0; 491 } else { 492 status = acpi_gsb_i2c_write_bytes(client, command, 493 gsb->data, info->access_length); 494 } 495 break; 496 497 default: 498 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n", 499 accessor_type, client->addr); 500 ret = AE_BAD_PARAMETER; 501 goto err; 502 } 503 504 gsb->status = status; 505 506 err: 507 kfree(client); 508 ACPI_FREE(ares); 509 return ret; 510} 511 512 513static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter) 514{ 515 acpi_handle handle; 516 struct acpi_i2c_handler_data *data; 517 acpi_status status; 518 519 if (!adapter->dev.parent) 520 return -ENODEV; 521 522 handle = ACPI_HANDLE(adapter->dev.parent); 523 524 if (!handle) 525 return -ENODEV; 526 527 data = kzalloc(sizeof(struct acpi_i2c_handler_data), 528 GFP_KERNEL); 529 if (!data) 530 return -ENOMEM; 531 532 data->adapter = adapter; 533 status = acpi_bus_attach_private_data(handle, (void *)data); 534 if (ACPI_FAILURE(status)) { 535 kfree(data); 536 return -ENOMEM; 537 } 538 539 status = acpi_install_address_space_handler(handle, 540 ACPI_ADR_SPACE_GSBUS, 541 &acpi_i2c_space_handler, 542 NULL, 543 data); 544 if (ACPI_FAILURE(status)) { 545 dev_err(&adapter->dev, "Error installing i2c space handler\n"); 546 acpi_bus_detach_private_data(handle); 547 kfree(data); 548 return -ENOMEM; 549 } 550 551 acpi_walk_dep_device_list(handle); 552 return 0; 553} 554 555static void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter) 556{ 557 acpi_handle handle; 558 struct acpi_i2c_handler_data *data; 559 acpi_status status; 560 561 if (!adapter->dev.parent) 562 return; 563 564 handle = ACPI_HANDLE(adapter->dev.parent); 565 566 if (!handle) 567 return; 568 569 acpi_remove_address_space_handler(handle, 570 ACPI_ADR_SPACE_GSBUS, 571 &acpi_i2c_space_handler); 572 573 status = acpi_bus_get_private_data(handle, (void **)&data); 574 if (ACPI_SUCCESS(status)) 575 kfree(data); 576 577 acpi_bus_detach_private_data(handle); 578} 579#else /* CONFIG_ACPI_I2C_OPREGION */ 580static inline void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter) 581{ } 582 583static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter) 584{ return 0; } 585#endif /* CONFIG_ACPI_I2C_OPREGION */ 586 587/* ------------------------------------------------------------------------- */ 588 589static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, 590 const struct i2c_client *client) 591{ 592 while (id->name[0]) { 593 if (strcmp(client->name, id->name) == 0) 594 return id; 595 id++; 596 } 597 return NULL; 598} 599 600static int i2c_device_match(struct device *dev, struct device_driver *drv) 601{ 602 struct i2c_client *client = i2c_verify_client(dev); 603 struct i2c_driver *driver; 604 605 if (!client) 606 return 0; 607 608 /* Attempt an OF style match */ 609 if (of_driver_match_device(dev, drv)) 610 return 1; 611 612 /* Then ACPI style match */ 613 if (acpi_driver_match_device(dev, drv)) 614 return 1; 615 616 driver = to_i2c_driver(drv); 617 /* match on an id table if there is one */ 618 if (driver->id_table) 619 return i2c_match_id(driver->id_table, client) != NULL; 620 621 return 0; 622} 623 624static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env) 625{ 626 struct i2c_client *client = to_i2c_client(dev); 627 int rc; 628 629 rc = acpi_device_uevent_modalias(dev, env); 630 if (rc != -ENODEV) 631 return rc; 632 633 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name); 634} 635 636/* i2c bus recovery routines */ 637static int get_scl_gpio_value(struct i2c_adapter *adap) 638{ 639 return gpio_get_value(adap->bus_recovery_info->scl_gpio); 640} 641 642static void set_scl_gpio_value(struct i2c_adapter *adap, int val) 643{ 644 gpio_set_value(adap->bus_recovery_info->scl_gpio, val); 645} 646 647static int get_sda_gpio_value(struct i2c_adapter *adap) 648{ 649 return gpio_get_value(adap->bus_recovery_info->sda_gpio); 650} 651 652static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap) 653{ 654 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 655 struct device *dev = &adap->dev; 656 int ret = 0; 657 658 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN | 659 GPIOF_OUT_INIT_HIGH, "i2c-scl"); 660 if (ret) { 661 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio); 662 return ret; 663 } 664 665 if (bri->get_sda) { 666 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) { 667 /* work without SDA polling */ 668 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n", 669 bri->sda_gpio); 670 bri->get_sda = NULL; 671 } 672 } 673 674 return ret; 675} 676 677static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap) 678{ 679 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 680 681 if (bri->get_sda) 682 gpio_free(bri->sda_gpio); 683 684 gpio_free(bri->scl_gpio); 685} 686 687/* 688 * We are generating clock pulses. ndelay() determines durating of clk pulses. 689 * We will generate clock with rate 100 KHz and so duration of both clock levels 690 * is: delay in ns = (10^6 / 100) / 2 691 */ 692#define RECOVERY_NDELAY 5000 693#define RECOVERY_CLK_CNT 9 694 695static int i2c_generic_recovery(struct i2c_adapter *adap) 696{ 697 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 698 int i = 0, val = 1, ret = 0; 699 700 if (bri->prepare_recovery) 701 bri->prepare_recovery(adap); 702 703 bri->set_scl(adap, val); 704 ndelay(RECOVERY_NDELAY); 705 706 /* 707 * By this time SCL is high, as we need to give 9 falling-rising edges 708 */ 709 while (i++ < RECOVERY_CLK_CNT * 2) { 710 if (val) { 711 /* Break if SDA is high */ 712 if (bri->get_sda && bri->get_sda(adap)) 713 break; 714 /* SCL shouldn't be low here */ 715 if (!bri->get_scl(adap)) { 716 dev_err(&adap->dev, 717 "SCL is stuck low, exit recovery\n"); 718 ret = -EBUSY; 719 break; 720 } 721 } 722 723 val = !val; 724 bri->set_scl(adap, val); 725 ndelay(RECOVERY_NDELAY); 726 } 727 728 if (bri->unprepare_recovery) 729 bri->unprepare_recovery(adap); 730 731 return ret; 732} 733 734int i2c_generic_scl_recovery(struct i2c_adapter *adap) 735{ 736 return i2c_generic_recovery(adap); 737} 738EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery); 739 740int i2c_generic_gpio_recovery(struct i2c_adapter *adap) 741{ 742 int ret; 743 744 ret = i2c_get_gpios_for_recovery(adap); 745 if (ret) 746 return ret; 747 748 ret = i2c_generic_recovery(adap); 749 i2c_put_gpios_for_recovery(adap); 750 751 return ret; 752} 753EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery); 754 755int i2c_recover_bus(struct i2c_adapter *adap) 756{ 757 if (!adap->bus_recovery_info) 758 return -EOPNOTSUPP; 759 760 dev_dbg(&adap->dev, "Trying i2c bus recovery\n"); 761 return adap->bus_recovery_info->recover_bus(adap); 762} 763EXPORT_SYMBOL_GPL(i2c_recover_bus); 764 765static void i2c_init_recovery(struct i2c_adapter *adap) 766{ 767 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; 768 char *err_str; 769 770 if (!bri) 771 return; 772 773 if (!bri->recover_bus) { 774 err_str = "no recover_bus() found"; 775 goto err; 776 } 777 778 /* Generic GPIO recovery */ 779 if (bri->recover_bus == i2c_generic_gpio_recovery) { 780 if (!gpio_is_valid(bri->scl_gpio)) { 781 err_str = "invalid SCL gpio"; 782 goto err; 783 } 784 785 if (gpio_is_valid(bri->sda_gpio)) 786 bri->get_sda = get_sda_gpio_value; 787 else 788 bri->get_sda = NULL; 789 790 bri->get_scl = get_scl_gpio_value; 791 bri->set_scl = set_scl_gpio_value; 792 } else if (bri->recover_bus == i2c_generic_scl_recovery) { 793 /* Generic SCL recovery */ 794 if (!bri->set_scl || !bri->get_scl) { 795 err_str = "no {get|set}_scl() found"; 796 goto err; 797 } 798 } 799 800 return; 801 err: 802 dev_err(&adap->dev, "Not using recovery: %s\n", err_str); 803 adap->bus_recovery_info = NULL; 804} 805 806static int i2c_device_probe(struct device *dev) 807{ 808 struct i2c_client *client = i2c_verify_client(dev); 809 struct i2c_driver *driver; 810 int status; 811 812 if (!client) 813 return 0; 814 815 if (!client->irq) { 816 int irq = -ENOENT; 817 818 if (dev->of_node) { 819 irq = of_irq_get_byname(dev->of_node, "irq"); 820 if (irq == -EINVAL || irq == -ENODATA) 821 irq = of_irq_get(dev->of_node, 0); 822 } else if (ACPI_COMPANION(dev)) { 823 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0); 824 } 825 if (irq == -EPROBE_DEFER) 826 return irq; 827 if (irq < 0) 828 irq = 0; 829 830 client->irq = irq; 831 } 832 833 driver = to_i2c_driver(dev->driver); 834 if (!driver->probe || !driver->id_table) 835 return -ENODEV; 836 837 if (client->flags & I2C_CLIENT_WAKE) { 838 int wakeirq = -ENOENT; 839 840 if (dev->of_node) { 841 wakeirq = of_irq_get_byname(dev->of_node, "wakeup"); 842 if (wakeirq == -EPROBE_DEFER) 843 return wakeirq; 844 } 845 846 device_init_wakeup(&client->dev, true); 847 848 if (wakeirq > 0 && wakeirq != client->irq) 849 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq); 850 else if (client->irq > 0) 851 status = dev_pm_set_wake_irq(dev, client->irq); 852 else 853 status = 0; 854 855 if (status) 856 dev_warn(&client->dev, "failed to set up wakeup irq"); 857 } 858 859 dev_dbg(dev, "probe\n"); 860 861 status = of_clk_set_defaults(dev->of_node, false); 862 if (status < 0) 863 goto err_clear_wakeup_irq; 864 865 status = dev_pm_domain_attach(&client->dev, true); 866 if (status == -EPROBE_DEFER) 867 goto err_clear_wakeup_irq; 868 869 status = driver->probe(client, i2c_match_id(driver->id_table, client)); 870 if (status) 871 goto err_detach_pm_domain; 872 873 return 0; 874 875err_detach_pm_domain: 876 dev_pm_domain_detach(&client->dev, true); 877err_clear_wakeup_irq: 878 dev_pm_clear_wake_irq(&client->dev); 879 device_init_wakeup(&client->dev, false); 880 return status; 881} 882 883static int i2c_device_remove(struct device *dev) 884{ 885 struct i2c_client *client = i2c_verify_client(dev); 886 struct i2c_driver *driver; 887 int status = 0; 888 889 if (!client || !dev->driver) 890 return 0; 891 892 driver = to_i2c_driver(dev->driver); 893 if (driver->remove) { 894 dev_dbg(dev, "remove\n"); 895 status = driver->remove(client); 896 } 897 898 dev_pm_domain_detach(&client->dev, true); 899 900 dev_pm_clear_wake_irq(&client->dev); 901 device_init_wakeup(&client->dev, false); 902 903 return status; 904} 905 906static void i2c_device_shutdown(struct device *dev) 907{ 908 struct i2c_client *client = i2c_verify_client(dev); 909 struct i2c_driver *driver; 910 911 if (!client || !dev->driver) 912 return; 913 driver = to_i2c_driver(dev->driver); 914 if (driver->shutdown) 915 driver->shutdown(client); 916} 917 918static void i2c_client_dev_release(struct device *dev) 919{ 920 kfree(to_i2c_client(dev)); 921} 922 923static ssize_t 924show_name(struct device *dev, struct device_attribute *attr, char *buf) 925{ 926 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? 927 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); 928} 929static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 930 931static ssize_t 932show_modalias(struct device *dev, struct device_attribute *attr, char *buf) 933{ 934 struct i2c_client *client = to_i2c_client(dev); 935 int len; 936 937 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1); 938 if (len != -ENODEV) 939 return len; 940 941 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); 942} 943static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL); 944 945static struct attribute *i2c_dev_attrs[] = { 946 &dev_attr_name.attr, 947 /* modalias helps coldplug: modprobe $(cat .../modalias) */ 948 &dev_attr_modalias.attr, 949 NULL 950}; 951ATTRIBUTE_GROUPS(i2c_dev); 952 953struct bus_type i2c_bus_type = { 954 .name = "i2c", 955 .match = i2c_device_match, 956 .probe = i2c_device_probe, 957 .remove = i2c_device_remove, 958 .shutdown = i2c_device_shutdown, 959}; 960EXPORT_SYMBOL_GPL(i2c_bus_type); 961 962static struct device_type i2c_client_type = { 963 .groups = i2c_dev_groups, 964 .uevent = i2c_device_uevent, 965 .release = i2c_client_dev_release, 966}; 967 968 969/** 970 * i2c_verify_client - return parameter as i2c_client, or NULL 971 * @dev: device, probably from some driver model iterator 972 * 973 * When traversing the driver model tree, perhaps using driver model 974 * iterators like @device_for_each_child(), you can't assume very much 975 * about the nodes you find. Use this function to avoid oopses caused 976 * by wrongly treating some non-I2C device as an i2c_client. 977 */ 978struct i2c_client *i2c_verify_client(struct device *dev) 979{ 980 return (dev->type == &i2c_client_type) 981 ? to_i2c_client(dev) 982 : NULL; 983} 984EXPORT_SYMBOL(i2c_verify_client); 985 986 987/* Return a unique address which takes the flags of the client into account */ 988static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client) 989{ 990 unsigned short addr = client->addr; 991 992 /* For some client flags, add an arbitrary offset to avoid collisions */ 993 if (client->flags & I2C_CLIENT_TEN) 994 addr |= I2C_ADDR_OFFSET_TEN_BIT; 995 996 if (client->flags & I2C_CLIENT_SLAVE) 997 addr |= I2C_ADDR_OFFSET_SLAVE; 998 999 return addr; 1000} 1001 1002/* This is a permissive address validity check, I2C address map constraints 1003 * are purposely not enforced, except for the general call address. */ 1004static int i2c_check_addr_validity(unsigned addr, unsigned short flags) 1005{ 1006 if (flags & I2C_CLIENT_TEN) { 1007 /* 10-bit address, all values are valid */ 1008 if (addr > 0x3ff) 1009 return -EINVAL; 1010 } else { 1011 /* 7-bit address, reject the general call address */ 1012 if (addr == 0x00 || addr > 0x7f) 1013 return -EINVAL; 1014 } 1015 return 0; 1016} 1017 1018/* And this is a strict address validity check, used when probing. If a 1019 * device uses a reserved address, then it shouldn't be probed. 7-bit 1020 * addressing is assumed, 10-bit address devices are rare and should be 1021 * explicitly enumerated. */ 1022static int i2c_check_7bit_addr_validity_strict(unsigned short addr) 1023{ 1024 /* 1025 * Reserved addresses per I2C specification: 1026 * 0x00 General call address / START byte 1027 * 0x01 CBUS address 1028 * 0x02 Reserved for different bus format 1029 * 0x03 Reserved for future purposes 1030 * 0x04-0x07 Hs-mode master code 1031 * 0x78-0x7b 10-bit slave addressing 1032 * 0x7c-0x7f Reserved for future purposes 1033 */ 1034 if (addr < 0x08 || addr > 0x77) 1035 return -EINVAL; 1036 return 0; 1037} 1038 1039static int __i2c_check_addr_busy(struct device *dev, void *addrp) 1040{ 1041 struct i2c_client *client = i2c_verify_client(dev); 1042 int addr = *(int *)addrp; 1043 1044 if (client && i2c_encode_flags_to_addr(client) == addr) 1045 return -EBUSY; 1046 return 0; 1047} 1048 1049/* walk up mux tree */ 1050static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) 1051{ 1052 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 1053 int result; 1054 1055 result = device_for_each_child(&adapter->dev, &addr, 1056 __i2c_check_addr_busy); 1057 1058 if (!result && parent) 1059 result = i2c_check_mux_parents(parent, addr); 1060 1061 return result; 1062} 1063 1064/* recurse down mux tree */ 1065static int i2c_check_mux_children(struct device *dev, void *addrp) 1066{ 1067 int result; 1068 1069 if (dev->type == &i2c_adapter_type) 1070 result = device_for_each_child(dev, addrp, 1071 i2c_check_mux_children); 1072 else 1073 result = __i2c_check_addr_busy(dev, addrp); 1074 1075 return result; 1076} 1077 1078static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) 1079{ 1080 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 1081 int result = 0; 1082 1083 if (parent) 1084 result = i2c_check_mux_parents(parent, addr); 1085 1086 if (!result) 1087 result = device_for_each_child(&adapter->dev, &addr, 1088 i2c_check_mux_children); 1089 1090 return result; 1091} 1092 1093/** 1094 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment 1095 * @adapter: Target I2C bus segment 1096 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT 1097 * locks only this branch in the adapter tree 1098 */ 1099static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, 1100 unsigned int flags) 1101{ 1102 rt_mutex_lock(&adapter->bus_lock); 1103} 1104 1105/** 1106 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment 1107 * @adapter: Target I2C bus segment 1108 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT 1109 * trylocks only this branch in the adapter tree 1110 */ 1111static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, 1112 unsigned int flags) 1113{ 1114 return rt_mutex_trylock(&adapter->bus_lock); 1115} 1116 1117/** 1118 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment 1119 * @adapter: Target I2C bus segment 1120 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT 1121 * unlocks only this branch in the adapter tree 1122 */ 1123static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, 1124 unsigned int flags) 1125{ 1126 rt_mutex_unlock(&adapter->bus_lock); 1127} 1128 1129static void i2c_dev_set_name(struct i2c_adapter *adap, 1130 struct i2c_client *client) 1131{ 1132 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 1133 1134 if (adev) { 1135 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev)); 1136 return; 1137 } 1138 1139 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), 1140 i2c_encode_flags_to_addr(client)); 1141} 1142 1143/** 1144 * i2c_new_device - instantiate an i2c device 1145 * @adap: the adapter managing the device 1146 * @info: describes one I2C device; bus_num is ignored 1147 * Context: can sleep 1148 * 1149 * Create an i2c device. Binding is handled through driver model 1150 * probe()/remove() methods. A driver may be bound to this device when we 1151 * return from this function, or any later moment (e.g. maybe hotplugging will 1152 * load the driver module). This call is not appropriate for use by mainboard 1153 * initialization logic, which usually runs during an arch_initcall() long 1154 * before any i2c_adapter could exist. 1155 * 1156 * This returns the new i2c client, which may be saved for later use with 1157 * i2c_unregister_device(); or NULL to indicate an error. 1158 */ 1159struct i2c_client * 1160i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info) 1161{ 1162 struct i2c_client *client; 1163 int status; 1164 1165 client = kzalloc(sizeof *client, GFP_KERNEL); 1166 if (!client) 1167 return NULL; 1168 1169 client->adapter = adap; 1170 1171 client->dev.platform_data = info->platform_data; 1172 1173 if (info->archdata) 1174 client->dev.archdata = *info->archdata; 1175 1176 client->flags = info->flags; 1177 client->addr = info->addr; 1178 client->irq = info->irq; 1179 1180 strlcpy(client->name, info->type, sizeof(client->name)); 1181 1182 status = i2c_check_addr_validity(client->addr, client->flags); 1183 if (status) { 1184 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", 1185 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); 1186 goto out_err_silent; 1187 } 1188 1189 /* Check for address business */ 1190 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); 1191 if (status) 1192 goto out_err; 1193 1194 client->dev.parent = &client->adapter->dev; 1195 client->dev.bus = &i2c_bus_type; 1196 client->dev.type = &i2c_client_type; 1197 client->dev.of_node = info->of_node; 1198 client->dev.fwnode = info->fwnode; 1199 1200 i2c_dev_set_name(adap, client); 1201 status = device_register(&client->dev); 1202 if (status) 1203 goto out_err; 1204 1205 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", 1206 client->name, dev_name(&client->dev)); 1207 1208 return client; 1209 1210out_err: 1211 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x " 1212 "(%d)\n", client->name, client->addr, status); 1213out_err_silent: 1214 kfree(client); 1215 return NULL; 1216} 1217EXPORT_SYMBOL_GPL(i2c_new_device); 1218 1219 1220/** 1221 * i2c_unregister_device - reverse effect of i2c_new_device() 1222 * @client: value returned from i2c_new_device() 1223 * Context: can sleep 1224 */ 1225void i2c_unregister_device(struct i2c_client *client) 1226{ 1227 if (client->dev.of_node) 1228 of_node_clear_flag(client->dev.of_node, OF_POPULATED); 1229 if (ACPI_COMPANION(&client->dev)) 1230 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev)); 1231 device_unregister(&client->dev); 1232} 1233EXPORT_SYMBOL_GPL(i2c_unregister_device); 1234 1235 1236static const struct i2c_device_id dummy_id[] = { 1237 { "dummy", 0 }, 1238 { }, 1239}; 1240 1241static int dummy_probe(struct i2c_client *client, 1242 const struct i2c_device_id *id) 1243{ 1244 return 0; 1245} 1246 1247static int dummy_remove(struct i2c_client *client) 1248{ 1249 return 0; 1250} 1251 1252static struct i2c_driver dummy_driver = { 1253 .driver.name = "dummy", 1254 .probe = dummy_probe, 1255 .remove = dummy_remove, 1256 .id_table = dummy_id, 1257}; 1258 1259/** 1260 * i2c_new_dummy - return a new i2c device bound to a dummy driver 1261 * @adapter: the adapter managing the device 1262 * @address: seven bit address to be used 1263 * Context: can sleep 1264 * 1265 * This returns an I2C client bound to the "dummy" driver, intended for use 1266 * with devices that consume multiple addresses. Examples of such chips 1267 * include various EEPROMS (like 24c04 and 24c08 models). 1268 * 1269 * These dummy devices have two main uses. First, most I2C and SMBus calls 1270 * except i2c_transfer() need a client handle; the dummy will be that handle. 1271 * And second, this prevents the specified address from being bound to a 1272 * different driver. 1273 * 1274 * This returns the new i2c client, which should be saved for later use with 1275 * i2c_unregister_device(); or NULL to indicate an error. 1276 */ 1277struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address) 1278{ 1279 struct i2c_board_info info = { 1280 I2C_BOARD_INFO("dummy", address), 1281 }; 1282 1283 return i2c_new_device(adapter, &info); 1284} 1285EXPORT_SYMBOL_GPL(i2c_new_dummy); 1286 1287/** 1288 * i2c_new_secondary_device - Helper to get the instantiated secondary address 1289 * and create the associated device 1290 * @client: Handle to the primary client 1291 * @name: Handle to specify which secondary address to get 1292 * @default_addr: Used as a fallback if no secondary address was specified 1293 * Context: can sleep 1294 * 1295 * I2C clients can be composed of multiple I2C slaves bound together in a single 1296 * component. The I2C client driver then binds to the master I2C slave and needs 1297 * to create I2C dummy clients to communicate with all the other slaves. 1298 * 1299 * This function creates and returns an I2C dummy client whose I2C address is 1300 * retrieved from the platform firmware based on the given slave name. If no 1301 * address is specified by the firmware default_addr is used. 1302 * 1303 * On DT-based platforms the address is retrieved from the "reg" property entry 1304 * cell whose "reg-names" value matches the slave name. 1305 * 1306 * This returns the new i2c client, which should be saved for later use with 1307 * i2c_unregister_device(); or NULL to indicate an error. 1308 */ 1309struct i2c_client *i2c_new_secondary_device(struct i2c_client *client, 1310 const char *name, 1311 u16 default_addr) 1312{ 1313 struct device_node *np = client->dev.of_node; 1314 u32 addr = default_addr; 1315 int i; 1316 1317 if (np) { 1318 i = of_property_match_string(np, "reg-names", name); 1319 if (i >= 0) 1320 of_property_read_u32_index(np, "reg", i, &addr); 1321 } 1322 1323 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr); 1324 return i2c_new_dummy(client->adapter, addr); 1325} 1326EXPORT_SYMBOL_GPL(i2c_new_secondary_device); 1327 1328/* ------------------------------------------------------------------------- */ 1329 1330/* I2C bus adapters -- one roots each I2C or SMBUS segment */ 1331 1332static void i2c_adapter_dev_release(struct device *dev) 1333{ 1334 struct i2c_adapter *adap = to_i2c_adapter(dev); 1335 complete(&adap->dev_released); 1336} 1337 1338/* 1339 * This function is only needed for mutex_lock_nested, so it is never 1340 * called unless locking correctness checking is enabled. Thus we 1341 * make it inline to avoid a compiler warning. That's what gcc ends up 1342 * doing anyway. 1343 */ 1344static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter) 1345{ 1346 unsigned int depth = 0; 1347 1348 while ((adapter = i2c_parent_is_i2c_adapter(adapter))) 1349 depth++; 1350 1351 return depth; 1352} 1353 1354/* 1355 * Let users instantiate I2C devices through sysfs. This can be used when 1356 * platform initialization code doesn't contain the proper data for 1357 * whatever reason. Also useful for drivers that do device detection and 1358 * detection fails, either because the device uses an unexpected address, 1359 * or this is a compatible device with different ID register values. 1360 * 1361 * Parameter checking may look overzealous, but we really don't want 1362 * the user to provide incorrect parameters. 1363 */ 1364static ssize_t 1365i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr, 1366 const char *buf, size_t count) 1367{ 1368 struct i2c_adapter *adap = to_i2c_adapter(dev); 1369 struct i2c_board_info info; 1370 struct i2c_client *client; 1371 char *blank, end; 1372 int res; 1373 1374 memset(&info, 0, sizeof(struct i2c_board_info)); 1375 1376 blank = strchr(buf, ' '); 1377 if (!blank) { 1378 dev_err(dev, "%s: Missing parameters\n", "new_device"); 1379 return -EINVAL; 1380 } 1381 if (blank - buf > I2C_NAME_SIZE - 1) { 1382 dev_err(dev, "%s: Invalid device name\n", "new_device"); 1383 return -EINVAL; 1384 } 1385 memcpy(info.type, buf, blank - buf); 1386 1387 /* Parse remaining parameters, reject extra parameters */ 1388 res = sscanf(++blank, "%hi%c", &info.addr, &end); 1389 if (res < 1) { 1390 dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); 1391 return -EINVAL; 1392 } 1393 if (res > 1 && end != '\n') { 1394 dev_err(dev, "%s: Extra parameters\n", "new_device"); 1395 return -EINVAL; 1396 } 1397 1398 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) { 1399 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT; 1400 info.flags |= I2C_CLIENT_TEN; 1401 } 1402 1403 if (info.addr & I2C_ADDR_OFFSET_SLAVE) { 1404 info.addr &= ~I2C_ADDR_OFFSET_SLAVE; 1405 info.flags |= I2C_CLIENT_SLAVE; 1406 } 1407 1408 client = i2c_new_device(adap, &info); 1409 if (!client) 1410 return -EINVAL; 1411 1412 /* Keep track of the added device */ 1413 mutex_lock(&adap->userspace_clients_lock); 1414 list_add_tail(&client->detected, &adap->userspace_clients); 1415 mutex_unlock(&adap->userspace_clients_lock); 1416 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", 1417 info.type, info.addr); 1418 1419 return count; 1420} 1421static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device); 1422 1423/* 1424 * And of course let the users delete the devices they instantiated, if 1425 * they got it wrong. This interface can only be used to delete devices 1426 * instantiated by i2c_sysfs_new_device above. This guarantees that we 1427 * don't delete devices to which some kernel code still has references. 1428 * 1429 * Parameter checking may look overzealous, but we really don't want 1430 * the user to delete the wrong device. 1431 */ 1432static ssize_t 1433i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr, 1434 const char *buf, size_t count) 1435{ 1436 struct i2c_adapter *adap = to_i2c_adapter(dev); 1437 struct i2c_client *client, *next; 1438 unsigned short addr; 1439 char end; 1440 int res; 1441 1442 /* Parse parameters, reject extra parameters */ 1443 res = sscanf(buf, "%hi%c", &addr, &end); 1444 if (res < 1) { 1445 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); 1446 return -EINVAL; 1447 } 1448 if (res > 1 && end != '\n') { 1449 dev_err(dev, "%s: Extra parameters\n", "delete_device"); 1450 return -EINVAL; 1451 } 1452 1453 /* Make sure the device was added through sysfs */ 1454 res = -ENOENT; 1455 mutex_lock_nested(&adap->userspace_clients_lock, 1456 i2c_adapter_depth(adap)); 1457 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1458 detected) { 1459 if (i2c_encode_flags_to_addr(client) == addr) { 1460 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", 1461 "delete_device", client->name, client->addr); 1462 1463 list_del(&client->detected); 1464 i2c_unregister_device(client); 1465 res = count; 1466 break; 1467 } 1468 } 1469 mutex_unlock(&adap->userspace_clients_lock); 1470 1471 if (res < 0) 1472 dev_err(dev, "%s: Can't find device in list\n", 1473 "delete_device"); 1474 return res; 1475} 1476static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL, 1477 i2c_sysfs_delete_device); 1478 1479static struct attribute *i2c_adapter_attrs[] = { 1480 &dev_attr_name.attr, 1481 &dev_attr_new_device.attr, 1482 &dev_attr_delete_device.attr, 1483 NULL 1484}; 1485ATTRIBUTE_GROUPS(i2c_adapter); 1486 1487struct device_type i2c_adapter_type = { 1488 .groups = i2c_adapter_groups, 1489 .release = i2c_adapter_dev_release, 1490}; 1491EXPORT_SYMBOL_GPL(i2c_adapter_type); 1492 1493/** 1494 * i2c_verify_adapter - return parameter as i2c_adapter or NULL 1495 * @dev: device, probably from some driver model iterator 1496 * 1497 * When traversing the driver model tree, perhaps using driver model 1498 * iterators like @device_for_each_child(), you can't assume very much 1499 * about the nodes you find. Use this function to avoid oopses caused 1500 * by wrongly treating some non-I2C device as an i2c_adapter. 1501 */ 1502struct i2c_adapter *i2c_verify_adapter(struct device *dev) 1503{ 1504 return (dev->type == &i2c_adapter_type) 1505 ? to_i2c_adapter(dev) 1506 : NULL; 1507} 1508EXPORT_SYMBOL(i2c_verify_adapter); 1509 1510#ifdef CONFIG_I2C_COMPAT 1511static struct class_compat *i2c_adapter_compat_class; 1512#endif 1513 1514static void i2c_scan_static_board_info(struct i2c_adapter *adapter) 1515{ 1516 struct i2c_devinfo *devinfo; 1517 1518 down_read(&__i2c_board_lock); 1519 list_for_each_entry(devinfo, &__i2c_board_list, list) { 1520 if (devinfo->busnum == adapter->nr 1521 && !i2c_new_device(adapter, 1522 &devinfo->board_info)) 1523 dev_err(&adapter->dev, 1524 "Can't create device at 0x%02x\n", 1525 devinfo->board_info.addr); 1526 } 1527 up_read(&__i2c_board_lock); 1528} 1529 1530/* OF support code */ 1531 1532#if IS_ENABLED(CONFIG_OF) 1533static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap, 1534 struct device_node *node) 1535{ 1536 struct i2c_client *result; 1537 struct i2c_board_info info = {}; 1538 struct dev_archdata dev_ad = {}; 1539 const __be32 *addr_be; 1540 u32 addr; 1541 int len; 1542 1543 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name); 1544 1545 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) { 1546 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n", 1547 node->full_name); 1548 return ERR_PTR(-EINVAL); 1549 } 1550 1551 addr_be = of_get_property(node, "reg", &len); 1552 if (!addr_be || (len < sizeof(*addr_be))) { 1553 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n", 1554 node->full_name); 1555 return ERR_PTR(-EINVAL); 1556 } 1557 1558 addr = be32_to_cpup(addr_be); 1559 if (addr & I2C_TEN_BIT_ADDRESS) { 1560 addr &= ~I2C_TEN_BIT_ADDRESS; 1561 info.flags |= I2C_CLIENT_TEN; 1562 } 1563 1564 if (addr & I2C_OWN_SLAVE_ADDRESS) { 1565 addr &= ~I2C_OWN_SLAVE_ADDRESS; 1566 info.flags |= I2C_CLIENT_SLAVE; 1567 } 1568 1569 if (i2c_check_addr_validity(addr, info.flags)) { 1570 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n", 1571 info.addr, node->full_name); 1572 return ERR_PTR(-EINVAL); 1573 } 1574 1575 info.addr = addr; 1576 info.of_node = of_node_get(node); 1577 info.archdata = &dev_ad; 1578 1579 if (of_get_property(node, "wakeup-source", NULL)) 1580 info.flags |= I2C_CLIENT_WAKE; 1581 1582 result = i2c_new_device(adap, &info); 1583 if (result == NULL) { 1584 dev_err(&adap->dev, "of_i2c: Failure registering %s\n", 1585 node->full_name); 1586 of_node_put(node); 1587 return ERR_PTR(-EINVAL); 1588 } 1589 return result; 1590} 1591 1592static void of_i2c_register_devices(struct i2c_adapter *adap) 1593{ 1594 struct device_node *node; 1595 1596 /* Only register child devices if the adapter has a node pointer set */ 1597 if (!adap->dev.of_node) 1598 return; 1599 1600 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n"); 1601 1602 for_each_available_child_of_node(adap->dev.of_node, node) { 1603 if (of_node_test_and_set_flag(node, OF_POPULATED)) 1604 continue; 1605 of_i2c_register_device(adap, node); 1606 } 1607} 1608 1609static int of_dev_node_match(struct device *dev, void *data) 1610{ 1611 return dev->of_node == data; 1612} 1613 1614/* must call put_device() when done with returned i2c_client device */ 1615struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) 1616{ 1617 struct device *dev; 1618 struct i2c_client *client; 1619 1620 dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match); 1621 if (!dev) 1622 return NULL; 1623 1624 client = i2c_verify_client(dev); 1625 if (!client) 1626 put_device(dev); 1627 1628 return client; 1629} 1630EXPORT_SYMBOL(of_find_i2c_device_by_node); 1631 1632/* must call put_device() when done with returned i2c_adapter device */ 1633struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node) 1634{ 1635 struct device *dev; 1636 struct i2c_adapter *adapter; 1637 1638 dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match); 1639 if (!dev) 1640 return NULL; 1641 1642 adapter = i2c_verify_adapter(dev); 1643 if (!adapter) 1644 put_device(dev); 1645 1646 return adapter; 1647} 1648EXPORT_SYMBOL(of_find_i2c_adapter_by_node); 1649 1650/* must call i2c_put_adapter() when done with returned i2c_adapter device */ 1651struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node) 1652{ 1653 struct i2c_adapter *adapter; 1654 1655 adapter = of_find_i2c_adapter_by_node(node); 1656 if (!adapter) 1657 return NULL; 1658 1659 if (!try_module_get(adapter->owner)) { 1660 put_device(&adapter->dev); 1661 adapter = NULL; 1662 } 1663 1664 return adapter; 1665} 1666EXPORT_SYMBOL(of_get_i2c_adapter_by_node); 1667#else 1668static void of_i2c_register_devices(struct i2c_adapter *adap) { } 1669#endif /* CONFIG_OF */ 1670 1671static int i2c_do_add_adapter(struct i2c_driver *driver, 1672 struct i2c_adapter *adap) 1673{ 1674 /* Detect supported devices on that bus, and instantiate them */ 1675 i2c_detect(adap, driver); 1676 1677 /* Let legacy drivers scan this bus for matching devices */ 1678 if (driver->attach_adapter) { 1679 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n", 1680 driver->driver.name); 1681 dev_warn(&adap->dev, "Please use another way to instantiate " 1682 "your i2c_client\n"); 1683 /* We ignore the return code; if it fails, too bad */ 1684 driver->attach_adapter(adap); 1685 } 1686 return 0; 1687} 1688 1689static int __process_new_adapter(struct device_driver *d, void *data) 1690{ 1691 return i2c_do_add_adapter(to_i2c_driver(d), data); 1692} 1693 1694static int i2c_register_adapter(struct i2c_adapter *adap) 1695{ 1696 int res = -EINVAL; 1697 1698 /* Can't register until after driver model init */ 1699 if (WARN_ON(!is_registered)) { 1700 res = -EAGAIN; 1701 goto out_list; 1702 } 1703 1704 /* Sanity checks */ 1705 if (WARN(!adap->name[0], "i2c adapter has no name")) 1706 goto out_list; 1707 1708 if (!adap->algo) { 1709 pr_err("adapter '%s': no algo supplied!\n", adap->name); 1710 goto out_list; 1711 } 1712 1713 if (!adap->lock_bus) { 1714 adap->lock_bus = i2c_adapter_lock_bus; 1715 adap->trylock_bus = i2c_adapter_trylock_bus; 1716 adap->unlock_bus = i2c_adapter_unlock_bus; 1717 } 1718 1719 rt_mutex_init(&adap->bus_lock); 1720 rt_mutex_init(&adap->mux_lock); 1721 mutex_init(&adap->userspace_clients_lock); 1722 INIT_LIST_HEAD(&adap->userspace_clients); 1723 1724 /* Set default timeout to 1 second if not already set */ 1725 if (adap->timeout == 0) 1726 adap->timeout = HZ; 1727 1728 dev_set_name(&adap->dev, "i2c-%d", adap->nr); 1729 adap->dev.bus = &i2c_bus_type; 1730 adap->dev.type = &i2c_adapter_type; 1731 res = device_register(&adap->dev); 1732 if (res) { 1733 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res); 1734 goto out_list; 1735 } 1736 1737 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); 1738 1739 pm_runtime_no_callbacks(&adap->dev); 1740 pm_suspend_ignore_children(&adap->dev, true); 1741 pm_runtime_enable(&adap->dev); 1742 1743#ifdef CONFIG_I2C_COMPAT 1744 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, 1745 adap->dev.parent); 1746 if (res) 1747 dev_warn(&adap->dev, 1748 "Failed to create compatibility class link\n"); 1749#endif 1750 1751 i2c_init_recovery(adap); 1752 1753 /* create pre-declared device nodes */ 1754 of_i2c_register_devices(adap); 1755 acpi_i2c_register_devices(adap); 1756 acpi_i2c_install_space_handler(adap); 1757 1758 if (adap->nr < __i2c_first_dynamic_bus_num) 1759 i2c_scan_static_board_info(adap); 1760 1761 /* Notify drivers */ 1762 mutex_lock(&core_lock); 1763 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); 1764 mutex_unlock(&core_lock); 1765 1766 return 0; 1767 1768out_list: 1769 mutex_lock(&core_lock); 1770 idr_remove(&i2c_adapter_idr, adap->nr); 1771 mutex_unlock(&core_lock); 1772 return res; 1773} 1774 1775/** 1776 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1 1777 * @adap: the adapter to register (with adap->nr initialized) 1778 * Context: can sleep 1779 * 1780 * See i2c_add_numbered_adapter() for details. 1781 */ 1782static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) 1783{ 1784 int id; 1785 1786 mutex_lock(&core_lock); 1787 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); 1788 mutex_unlock(&core_lock); 1789 if (WARN(id < 0, "couldn't get idr")) 1790 return id == -ENOSPC ? -EBUSY : id; 1791 1792 return i2c_register_adapter(adap); 1793} 1794 1795/** 1796 * i2c_add_adapter - declare i2c adapter, use dynamic bus number 1797 * @adapter: the adapter to add 1798 * Context: can sleep 1799 * 1800 * This routine is used to declare an I2C adapter when its bus number 1801 * doesn't matter or when its bus number is specified by an dt alias. 1802 * Examples of bases when the bus number doesn't matter: I2C adapters 1803 * dynamically added by USB links or PCI plugin cards. 1804 * 1805 * When this returns zero, a new bus number was allocated and stored 1806 * in adap->nr, and the specified adapter became available for clients. 1807 * Otherwise, a negative errno value is returned. 1808 */ 1809int i2c_add_adapter(struct i2c_adapter *adapter) 1810{ 1811 struct device *dev = &adapter->dev; 1812 int id; 1813 1814 if (dev->of_node) { 1815 id = of_alias_get_id(dev->of_node, "i2c"); 1816 if (id >= 0) { 1817 adapter->nr = id; 1818 return __i2c_add_numbered_adapter(adapter); 1819 } 1820 } 1821 1822 mutex_lock(&core_lock); 1823 id = idr_alloc(&i2c_adapter_idr, adapter, 1824 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL); 1825 mutex_unlock(&core_lock); 1826 if (WARN(id < 0, "couldn't get idr")) 1827 return id; 1828 1829 adapter->nr = id; 1830 1831 return i2c_register_adapter(adapter); 1832} 1833EXPORT_SYMBOL(i2c_add_adapter); 1834 1835/** 1836 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number 1837 * @adap: the adapter to register (with adap->nr initialized) 1838 * Context: can sleep 1839 * 1840 * This routine is used to declare an I2C adapter when its bus number 1841 * matters. For example, use it for I2C adapters from system-on-chip CPUs, 1842 * or otherwise built in to the system's mainboard, and where i2c_board_info 1843 * is used to properly configure I2C devices. 1844 * 1845 * If the requested bus number is set to -1, then this function will behave 1846 * identically to i2c_add_adapter, and will dynamically assign a bus number. 1847 * 1848 * If no devices have pre-been declared for this bus, then be sure to 1849 * register the adapter before any dynamically allocated ones. Otherwise 1850 * the required bus ID may not be available. 1851 * 1852 * When this returns zero, the specified adapter became available for 1853 * clients using the bus number provided in adap->nr. Also, the table 1854 * of I2C devices pre-declared using i2c_register_board_info() is scanned, 1855 * and the appropriate driver model device nodes are created. Otherwise, a 1856 * negative errno value is returned. 1857 */ 1858int i2c_add_numbered_adapter(struct i2c_adapter *adap) 1859{ 1860 if (adap->nr == -1) /* -1 means dynamically assign bus id */ 1861 return i2c_add_adapter(adap); 1862 1863 return __i2c_add_numbered_adapter(adap); 1864} 1865EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); 1866 1867static void i2c_do_del_adapter(struct i2c_driver *driver, 1868 struct i2c_adapter *adapter) 1869{ 1870 struct i2c_client *client, *_n; 1871 1872 /* Remove the devices we created ourselves as the result of hardware 1873 * probing (using a driver's detect method) */ 1874 list_for_each_entry_safe(client, _n, &driver->clients, detected) { 1875 if (client->adapter == adapter) { 1876 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", 1877 client->name, client->addr); 1878 list_del(&client->detected); 1879 i2c_unregister_device(client); 1880 } 1881 } 1882} 1883 1884static int __unregister_client(struct device *dev, void *dummy) 1885{ 1886 struct i2c_client *client = i2c_verify_client(dev); 1887 if (client && strcmp(client->name, "dummy")) 1888 i2c_unregister_device(client); 1889 return 0; 1890} 1891 1892static int __unregister_dummy(struct device *dev, void *dummy) 1893{ 1894 struct i2c_client *client = i2c_verify_client(dev); 1895 if (client) 1896 i2c_unregister_device(client); 1897 return 0; 1898} 1899 1900static int __process_removed_adapter(struct device_driver *d, void *data) 1901{ 1902 i2c_do_del_adapter(to_i2c_driver(d), data); 1903 return 0; 1904} 1905 1906/** 1907 * i2c_del_adapter - unregister I2C adapter 1908 * @adap: the adapter being unregis…
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