i2c-core.c 87.5 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12
/* i2c-core.c - a device driver for the iic-bus interface		     */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 1995-99 Simon G. Vogl

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
W
Wolfram Sang 已提交
13
    GNU General Public License for more details.			     */
L
Linus Torvalds 已提交
14 15
/* ------------------------------------------------------------------------- */

16
/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
L
Linus Torvalds 已提交
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 22 23 24
   Michael Lawnick <michael.lawnick.ext@nsn.com>
   OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
   (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
   (c) 2013  Wolfram Sang <wsa@the-dreams.de>
25 26
   I2C ACPI code Copyright (C) 2014 Intel Corp
   Author: Lan Tianyu <tianyu.lan@intel.com>
W
Wolfram Sang 已提交
27
   I2C slave support (c) 2014 by Wolfram Sang <wsa@sang-engineering.com>
28
 */
L
Linus Torvalds 已提交
29

W
Wolfram Sang 已提交
30
#include <dt-bindings/i2c/i2c.h>
W
Wolfram Sang 已提交
31 32 33 34
#include <asm/uaccess.h>
#include <linux/acpi.h>
#include <linux/clk/clk-conf.h>
#include <linux/completion.h>
35
#include <linux/delay.h>
W
Wolfram Sang 已提交
36
#include <linux/err.h>
L
Linus Torvalds 已提交
37
#include <linux/errno.h>
38
#include <linux/gpio.h>
W
Wolfram Sang 已提交
39
#include <linux/hardirq.h>
L
Linus Torvalds 已提交
40 41
#include <linux/i2c.h>
#include <linux/idr.h>
W
Wolfram Sang 已提交
42 43 44 45 46
#include <linux/init.h>
#include <linux/irqflags.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/module.h>
47
#include <linux/mutex.h>
48
#include <linux/of_device.h>
W
Wolfram Sang 已提交
49
#include <linux/of.h>
50
#include <linux/of_irq.h>
51
#include <linux/pm_domain.h>
W
Wolfram Sang 已提交
52
#include <linux/pm_runtime.h>
53
#include <linux/pm_wakeirq.h>
54
#include <linux/property.h>
W
Wolfram Sang 已提交
55 56
#include <linux/rwsem.h>
#include <linux/slab.h>
L
Linus Torvalds 已提交
57

58 59
#include "i2c-core.h"

60 61
#define CREATE_TRACE_POINTS
#include <trace/events/i2c.h>
L
Linus Torvalds 已提交
62

63 64 65
#define I2C_ADDR_OFFSET_TEN_BIT	0xa000
#define I2C_ADDR_OFFSET_SLAVE	0x1000

66
/* core_lock protects i2c_adapter_idr, and guarantees
67
   that device detection, deletion of detected devices, and attach_adapter
L
Lars-Peter Clausen 已提交
68
   calls are serialized */
J
Jean Delvare 已提交
69
static DEFINE_MUTEX(core_lock);
L
Linus Torvalds 已提交
70 71
static DEFINE_IDR(i2c_adapter_idr);

72
static struct device_type i2c_client_type;
73
static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
74

75
static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
76
static bool is_registered;
77 78 79 80 81 82 83 84 85 86 87

void i2c_transfer_trace_reg(void)
{
	static_key_slow_inc(&i2c_trace_msg);
}

void i2c_transfer_trace_unreg(void)
{
	static_key_slow_dec(&i2c_trace_msg);
}

88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
#if defined(CONFIG_ACPI)
struct acpi_i2c_handler_data {
	struct acpi_connection_info info;
	struct i2c_adapter *adapter;
};

struct gsb_buffer {
	u8	status;
	u8	len;
	union {
		u16	wdata;
		u8	bdata;
		u8	data[0];
	};
} __packed;

104 105 106 107 108
struct acpi_i2c_lookup {
	struct i2c_board_info *info;
	acpi_handle adapter_handle;
	acpi_handle device_handle;
};
109

110 111 112 113 114 115 116
static int acpi_i2c_find_address(struct acpi_resource *ares, void *data)
{
	struct acpi_i2c_lookup *lookup = data;
	struct i2c_board_info *info = lookup->info;
	struct acpi_resource_i2c_serialbus *sb;
	acpi_handle adapter_handle;
	acpi_status status;
117

118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135
	if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
		return 1;

	sb = &ares->data.i2c_serial_bus;
	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
		return 1;

	/*
	 * Extract the ResourceSource and make sure that the handle matches
	 * with the I2C adapter handle.
	 */
	status = acpi_get_handle(lookup->device_handle,
				 sb->resource_source.string_ptr,
				 &adapter_handle);
	if (ACPI_SUCCESS(status) && adapter_handle == lookup->adapter_handle) {
		info->addr = sb->slave_address;
		if (sb->access_mode == ACPI_I2C_10BIT_MODE)
			info->flags |= I2C_CLIENT_TEN;
136 137 138 139 140 141 142 143 144 145
	}

	return 1;
}

static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
				       void *data, void **return_value)
{
	struct i2c_adapter *adapter = data;
	struct list_head resource_list;
146 147
	struct acpi_i2c_lookup lookup;
	struct resource_entry *entry;
148 149 150 151 152 153 154 155 156 157
	struct i2c_board_info info;
	struct acpi_device *adev;
	int ret;

	if (acpi_bus_get_device(handle, &adev))
		return AE_OK;
	if (acpi_bus_get_status(adev) || !adev->status.present)
		return AE_OK;

	memset(&info, 0, sizeof(info));
158
	info.fwnode = acpi_fwnode_handle(adev);
159

160
	memset(&lookup, 0, sizeof(lookup));
161
	lookup.adapter_handle = ACPI_HANDLE(&adapter->dev);
162 163 164 165 166 167 168
	lookup.device_handle = handle;
	lookup.info = &info;

	/*
	 * Look up for I2cSerialBus resource with ResourceSource that
	 * matches with this adapter.
	 */
169 170
	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list,
171
				     acpi_i2c_find_address, &lookup);
172 173 174 175 176
	acpi_dev_free_resource_list(&resource_list);

	if (ret < 0 || !info.addr)
		return AE_OK;

177 178 179 180 181 182 183 184 185 186 187 188 189 190
	/* Then fill IRQ number if any */
	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
	if (ret < 0)
		return AE_OK;

	resource_list_for_each_entry(entry, &resource_list) {
		if (resource_type(entry->res) == IORESOURCE_IRQ) {
			info.irq = entry->res->start;
			break;
		}
	}

	acpi_dev_free_resource_list(&resource_list);

191 192 193 194 195 196 197 198 199 200 201 202
	adev->power.flags.ignore_parent = true;
	strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
	if (!i2c_new_device(adapter, &info)) {
		adev->power.flags.ignore_parent = false;
		dev_err(&adapter->dev,
			"failed to add I2C device %s from ACPI\n",
			dev_name(&adev->dev));
	}

	return AE_OK;
}

203 204
#define ACPI_I2C_MAX_SCAN_DEPTH 32

205 206 207 208 209 210 211 212 213 214 215 216
/**
 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
 * @adap: pointer to adapter
 *
 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
 * namespace. When a device is found it will be added to the Linux device
 * model and bound to the corresponding ACPI handle.
 */
static void acpi_i2c_register_devices(struct i2c_adapter *adap)
{
	acpi_status status;

217
	if (!has_acpi_companion(&adap->dev))
218 219
		return;

220 221
	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
				     ACPI_I2C_MAX_SCAN_DEPTH,
222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302
				     acpi_i2c_add_device, NULL,
				     adap, NULL);
	if (ACPI_FAILURE(status))
		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
}

#else /* CONFIG_ACPI */
static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) { }
#endif /* CONFIG_ACPI */

#ifdef CONFIG_ACPI_I2C_OPREGION
static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
		u8 cmd, u8 *data, u8 data_len)
{

	struct i2c_msg msgs[2];
	int ret;
	u8 *buffer;

	buffer = kzalloc(data_len, GFP_KERNEL);
	if (!buffer)
		return AE_NO_MEMORY;

	msgs[0].addr = client->addr;
	msgs[0].flags = client->flags;
	msgs[0].len = 1;
	msgs[0].buf = &cmd;

	msgs[1].addr = client->addr;
	msgs[1].flags = client->flags | I2C_M_RD;
	msgs[1].len = data_len;
	msgs[1].buf = buffer;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0)
		dev_err(&client->adapter->dev, "i2c read failed\n");
	else
		memcpy(data, buffer, data_len);

	kfree(buffer);
	return ret;
}

static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
		u8 cmd, u8 *data, u8 data_len)
{

	struct i2c_msg msgs[1];
	u8 *buffer;
	int ret = AE_OK;

	buffer = kzalloc(data_len + 1, GFP_KERNEL);
	if (!buffer)
		return AE_NO_MEMORY;

	buffer[0] = cmd;
	memcpy(buffer + 1, data, data_len);

	msgs[0].addr = client->addr;
	msgs[0].flags = client->flags;
	msgs[0].len = data_len + 1;
	msgs[0].buf = buffer;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0)
		dev_err(&client->adapter->dev, "i2c write failed\n");

	kfree(buffer);
	return ret;
}

static acpi_status
acpi_i2c_space_handler(u32 function, acpi_physical_address command,
			u32 bits, u64 *value64,
			void *handler_context, void *region_context)
{
	struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
	struct acpi_i2c_handler_data *data = handler_context;
	struct acpi_connection_info *info = &data->info;
	struct acpi_resource_i2c_serialbus *sb;
	struct i2c_adapter *adapter = data->adapter;
303
	struct i2c_client *client;
304 305 306
	struct acpi_resource *ares;
	u32 accessor_type = function >> 16;
	u8 action = function & ACPI_IO_MASK;
307
	acpi_status ret;
308 309 310 311 312 313
	int status;

	ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
	if (ACPI_FAILURE(ret))
		return ret;

314 315 316 317 318 319
	client = kzalloc(sizeof(*client), GFP_KERNEL);
	if (!client) {
		ret = AE_NO_MEMORY;
		goto err;
	}

320 321 322 323 324 325 326 327 328 329 330
	if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	sb = &ares->data.i2c_serial_bus;
	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
		ret = AE_BAD_PARAMETER;
		goto err;
	}

331 332
	client->adapter = adapter;
	client->addr = sb->slave_address;
333 334

	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
335
		client->flags |= I2C_CLIENT_TEN;
336 337 338 339

	switch (accessor_type) {
	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
		if (action == ACPI_READ) {
340
			status = i2c_smbus_read_byte(client);
341 342 343 344 345
			if (status >= 0) {
				gsb->bdata = status;
				status = 0;
			}
		} else {
346
			status = i2c_smbus_write_byte(client, gsb->bdata);
347 348 349 350 351
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_BYTE:
		if (action == ACPI_READ) {
352
			status = i2c_smbus_read_byte_data(client, command);
353 354 355 356 357
			if (status >= 0) {
				gsb->bdata = status;
				status = 0;
			}
		} else {
358
			status = i2c_smbus_write_byte_data(client, command,
359 360 361 362 363 364
					gsb->bdata);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_WORD:
		if (action == ACPI_READ) {
365
			status = i2c_smbus_read_word_data(client, command);
366 367 368 369 370
			if (status >= 0) {
				gsb->wdata = status;
				status = 0;
			}
		} else {
371
			status = i2c_smbus_write_word_data(client, command,
372 373 374 375 376 377
					gsb->wdata);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
		if (action == ACPI_READ) {
378
			status = i2c_smbus_read_block_data(client, command,
379 380 381 382 383 384
					gsb->data);
			if (status >= 0) {
				gsb->len = status;
				status = 0;
			}
		} else {
385
			status = i2c_smbus_write_block_data(client, command,
386 387 388 389 390 391
					gsb->len, gsb->data);
		}
		break;

	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
		if (action == ACPI_READ) {
392
			status = acpi_gsb_i2c_read_bytes(client, command,
393 394 395 396
					gsb->data, info->access_length);
			if (status > 0)
				status = 0;
		} else {
397
			status = acpi_gsb_i2c_write_bytes(client, command,
398 399 400 401 402 403 404 405 406 407 408 409 410
					gsb->data, info->access_length);
		}
		break;

	default:
		pr_info("protocol(0x%02x) is not supported.\n", accessor_type);
		ret = AE_BAD_PARAMETER;
		goto err;
	}

	gsb->status = status;

 err:
411
	kfree(client);
412 413 414 415 416 417 418
	ACPI_FREE(ares);
	return ret;
}


static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
{
419
	acpi_handle handle;
420 421 422
	struct acpi_i2c_handler_data *data;
	acpi_status status;

423 424 425 426 427
	if (!adapter->dev.parent)
		return -ENODEV;

	handle = ACPI_HANDLE(adapter->dev.parent);

428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454
	if (!handle)
		return -ENODEV;

	data = kzalloc(sizeof(struct acpi_i2c_handler_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->adapter = adapter;
	status = acpi_bus_attach_private_data(handle, (void *)data);
	if (ACPI_FAILURE(status)) {
		kfree(data);
		return -ENOMEM;
	}

	status = acpi_install_address_space_handler(handle,
				ACPI_ADR_SPACE_GSBUS,
				&acpi_i2c_space_handler,
				NULL,
				data);
	if (ACPI_FAILURE(status)) {
		dev_err(&adapter->dev, "Error installing i2c space handler\n");
		acpi_bus_detach_private_data(handle);
		kfree(data);
		return -ENOMEM;
	}

455
	acpi_walk_dep_device_list(handle);
456 457 458 459 460
	return 0;
}

static void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
{
461
	acpi_handle handle;
462 463 464
	struct acpi_i2c_handler_data *data;
	acpi_status status;

465 466 467 468 469
	if (!adapter->dev.parent)
		return;

	handle = ACPI_HANDLE(adapter->dev.parent);

470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490
	if (!handle)
		return;

	acpi_remove_address_space_handler(handle,
				ACPI_ADR_SPACE_GSBUS,
				&acpi_i2c_space_handler);

	status = acpi_bus_get_private_data(handle, (void **)&data);
	if (ACPI_SUCCESS(status))
		kfree(data);

	acpi_bus_detach_private_data(handle);
}
#else /* CONFIG_ACPI_I2C_OPREGION */
static inline void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
{ }

static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
{ return 0; }
#endif /* CONFIG_ACPI_I2C_OPREGION */

491 492
/* ------------------------------------------------------------------------- */

493 494 495 496 497 498 499 500 501 502 503
static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
						const struct i2c_client *client)
{
	while (id->name[0]) {
		if (strcmp(client->name, id->name) == 0)
			return id;
		id++;
	}
	return NULL;
}

L
Linus Torvalds 已提交
504 505
static int i2c_device_match(struct device *dev, struct device_driver *drv)
{
506 507 508 509 510
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;

	if (!client)
		return 0;
D
David Brownell 已提交
511

512 513 514 515
	/* Attempt an OF style match */
	if (of_driver_match_device(dev, drv))
		return 1;

516 517 518 519
	/* Then ACPI style match */
	if (acpi_driver_match_device(dev, drv))
		return 1;

520
	driver = to_i2c_driver(drv);
521 522 523 524
	/* match on an id table if there is one */
	if (driver->id_table)
		return i2c_match_id(driver->id_table, client) != NULL;

525
	return 0;
L
Linus Torvalds 已提交
526 527
}

528
static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
D
David Brownell 已提交
529
{
530
	struct i2c_client *client = to_i2c_client(dev);
531 532 533 534 535
	int rc;

	rc = acpi_device_uevent_modalias(dev, env);
	if (rc != -ENODEV)
		return rc;
D
David Brownell 已提交
536

537
	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
D
David Brownell 已提交
538 539
}

540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604
/* i2c bus recovery routines */
static int get_scl_gpio_value(struct i2c_adapter *adap)
{
	return gpio_get_value(adap->bus_recovery_info->scl_gpio);
}

static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
{
	gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
}

static int get_sda_gpio_value(struct i2c_adapter *adap)
{
	return gpio_get_value(adap->bus_recovery_info->sda_gpio);
}

static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
	struct device *dev = &adap->dev;
	int ret = 0;

	ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
			GPIOF_OUT_INIT_HIGH, "i2c-scl");
	if (ret) {
		dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
		return ret;
	}

	if (bri->get_sda) {
		if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
			/* work without SDA polling */
			dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
					bri->sda_gpio);
			bri->get_sda = NULL;
		}
	}

	return ret;
}

static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;

	if (bri->get_sda)
		gpio_free(bri->sda_gpio);

	gpio_free(bri->scl_gpio);
}

/*
 * We are generating clock pulses. ndelay() determines durating of clk pulses.
 * We will generate clock with rate 100 KHz and so duration of both clock levels
 * is: delay in ns = (10^6 / 100) / 2
 */
#define RECOVERY_NDELAY		5000
#define RECOVERY_CLK_CNT	9

static int i2c_generic_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
	int i = 0, val = 1, ret = 0;

	if (bri->prepare_recovery)
605
		bri->prepare_recovery(adap);
606

607 608 609
	bri->set_scl(adap, val);
	ndelay(RECOVERY_NDELAY);

610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632
	/*
	 * By this time SCL is high, as we need to give 9 falling-rising edges
	 */
	while (i++ < RECOVERY_CLK_CNT * 2) {
		if (val) {
			/* Break if SDA is high */
			if (bri->get_sda && bri->get_sda(adap))
					break;
			/* SCL shouldn't be low here */
			if (!bri->get_scl(adap)) {
				dev_err(&adap->dev,
					"SCL is stuck low, exit recovery\n");
				ret = -EBUSY;
				break;
			}
		}

		val = !val;
		bri->set_scl(adap, val);
		ndelay(RECOVERY_NDELAY);
	}

	if (bri->unprepare_recovery)
633
		bri->unprepare_recovery(adap);
634 635 636 637 638 639 640 641

	return ret;
}

int i2c_generic_scl_recovery(struct i2c_adapter *adap)
{
	return i2c_generic_recovery(adap);
}
642
EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
643 644 645 646 647 648 649 650 651 652 653 654 655 656

int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
{
	int ret;

	ret = i2c_get_gpios_for_recovery(adap);
	if (ret)
		return ret;

	ret = i2c_generic_recovery(adap);
	i2c_put_gpios_for_recovery(adap);

	return ret;
}
657
EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
658 659 660 661 662 663 664 665 666

int i2c_recover_bus(struct i2c_adapter *adap)
{
	if (!adap->bus_recovery_info)
		return -EOPNOTSUPP;

	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
	return adap->bus_recovery_info->recover_bus(adap);
}
667
EXPORT_SYMBOL_GPL(i2c_recover_bus);
668

669
static int i2c_device_probe(struct device *dev)
L
Linus Torvalds 已提交
670
{
671 672
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;
673
	int status;
D
David Brownell 已提交
674

675 676 677
	if (!client)
		return 0;

678 679 680
	if (!client->irq) {
		int irq = -ENOENT;

681 682 683 684 685
		if (dev->of_node) {
			irq = of_irq_get_byname(dev->of_node, "irq");
			if (irq == -EINVAL || irq == -ENODATA)
				irq = of_irq_get(dev->of_node, 0);
		} else if (ACPI_COMPANION(dev)) {
686
			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
687
		}
688
		if (irq == -EPROBE_DEFER)
689
			return irq;
690 691
		if (irq < 0)
			irq = 0;
692 693 694 695

		client->irq = irq;
	}

696
	driver = to_i2c_driver(dev->driver);
J
Jean Delvare 已提交
697
	if (!driver->probe || !driver->id_table)
D
David Brownell 已提交
698
		return -ENODEV;
699

700 701 702 703 704 705 706 707 708 709 710 711 712 713
	if (client->flags & I2C_CLIENT_WAKE) {
		int wakeirq = -ENOENT;

		if (dev->of_node) {
			wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
			if (wakeirq == -EPROBE_DEFER)
				return wakeirq;
		}

		device_init_wakeup(&client->dev, true);

		if (wakeirq > 0 && wakeirq != client->irq)
			status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
		else if (client->irq > 0)
G
Grygorii Strashko 已提交
714
			status = dev_pm_set_wake_irq(dev, client->irq);
715 716 717 718 719 720 721
		else
			status = 0;

		if (status)
			dev_warn(&client->dev, "failed to set up wakeup irq");
	}

D
David Brownell 已提交
722
	dev_dbg(dev, "probe\n");
723

724 725
	status = of_clk_set_defaults(dev->of_node, false);
	if (status < 0)
726
		goto err_clear_wakeup_irq;
727

728
	status = dev_pm_domain_attach(&client->dev, true);
729 730 731 732 733 734
	if (status == -EPROBE_DEFER)
		goto err_clear_wakeup_irq;

	status = driver->probe(client, i2c_match_id(driver->id_table, client));
	if (status)
		goto err_detach_pm_domain;
735

736 737 738 739 740 741 742
	return 0;

err_detach_pm_domain:
	dev_pm_domain_detach(&client->dev, true);
err_clear_wakeup_irq:
	dev_pm_clear_wake_irq(&client->dev);
	device_init_wakeup(&client->dev, false);
743
	return status;
744
}
L
Linus Torvalds 已提交
745

746 747
static int i2c_device_remove(struct device *dev)
{
748
	struct i2c_client	*client = i2c_verify_client(dev);
D
David Brownell 已提交
749
	struct i2c_driver	*driver;
750
	int status = 0;
D
David Brownell 已提交
751

752
	if (!client || !dev->driver)
D
David Brownell 已提交
753 754 755 756 757 758 759
		return 0;

	driver = to_i2c_driver(dev->driver);
	if (driver->remove) {
		dev_dbg(dev, "remove\n");
		status = driver->remove(client);
	}
760

761
	dev_pm_domain_detach(&client->dev, true);
762 763 764 765

	dev_pm_clear_wake_irq(&client->dev);
	device_init_wakeup(&client->dev, false);

D
David Brownell 已提交
766
	return status;
L
Linus Torvalds 已提交
767 768
}

769
static void i2c_device_shutdown(struct device *dev)
L
Linus Torvalds 已提交
770
{
771
	struct i2c_client *client = i2c_verify_client(dev);
772 773
	struct i2c_driver *driver;

774
	if (!client || !dev->driver)
775 776 777
		return;
	driver = to_i2c_driver(dev->driver);
	if (driver->shutdown)
778
		driver->shutdown(client);
L
Linus Torvalds 已提交
779 780
}

781 782 783 784 785
static void i2c_client_dev_release(struct device *dev)
{
	kfree(to_i2c_client(dev));
}

Z
Zhenwen Xu 已提交
786
static ssize_t
787
show_name(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
788
{
789 790
	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
D
David Brownell 已提交
791
}
792
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
D
David Brownell 已提交
793

Z
Zhenwen Xu 已提交
794 795
static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
D
David Brownell 已提交
796 797
{
	struct i2c_client *client = to_i2c_client(dev);
798 799 800 801 802 803
	int len;

	len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
	if (len != -ENODEV)
		return len;

804
	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
D
David Brownell 已提交
805
}
806 807 808 809
static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);

static struct attribute *i2c_dev_attrs[] = {
	&dev_attr_name.attr,
D
David Brownell 已提交
810
	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
811 812 813
	&dev_attr_modalias.attr,
	NULL
};
814
ATTRIBUTE_GROUPS(i2c_dev);
815

J
Jon Smirl 已提交
816
struct bus_type i2c_bus_type = {
817 818 819 820 821
	.name		= "i2c",
	.match		= i2c_device_match,
	.probe		= i2c_device_probe,
	.remove		= i2c_device_remove,
	.shutdown	= i2c_device_shutdown,
822
};
J
Jon Smirl 已提交
823
EXPORT_SYMBOL_GPL(i2c_bus_type);
824

825
static struct device_type i2c_client_type = {
826
	.groups		= i2c_dev_groups,
827 828 829 830
	.uevent		= i2c_device_uevent,
	.release	= i2c_client_dev_release,
};

831 832 833 834 835 836 837 838 839 840 841 842

/**
 * i2c_verify_client - return parameter as i2c_client, or NULL
 * @dev: device, probably from some driver model iterator
 *
 * When traversing the driver model tree, perhaps using driver model
 * iterators like @device_for_each_child(), you can't assume very much
 * about the nodes you find.  Use this function to avoid oopses caused
 * by wrongly treating some non-I2C device as an i2c_client.
 */
struct i2c_client *i2c_verify_client(struct device *dev)
{
843
	return (dev->type == &i2c_client_type)
844 845 846 847 848 849
			? to_i2c_client(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);


850 851 852 853 854 855 856 857 858 859 860 861 862 863 864
/* Return a unique address which takes the flags of the client into account */
static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
{
	unsigned short addr = client->addr;

	/* For some client flags, add an arbitrary offset to avoid collisions */
	if (client->flags & I2C_CLIENT_TEN)
		addr |= I2C_ADDR_OFFSET_TEN_BIT;

	if (client->flags & I2C_CLIENT_SLAVE)
		addr |= I2C_ADDR_OFFSET_SLAVE;

	return addr;
}

865
/* This is a permissive address validity check, I2C address map constraints
L
Lucas De Marchi 已提交
866
 * are purposely not enforced, except for the general call address. */
867
static int i2c_check_addr_validity(unsigned addr, unsigned short flags)
868
{
869
	if (flags & I2C_CLIENT_TEN) {
870
		/* 10-bit address, all values are valid */
871
		if (addr > 0x3ff)
872 873 874
			return -EINVAL;
	} else {
		/* 7-bit address, reject the general call address */
875
		if (addr == 0x00 || addr > 0x7f)
876 877 878 879 880
			return -EINVAL;
	}
	return 0;
}

881 882 883 884
/* And this is a strict address validity check, used when probing. If a
 * device uses a reserved address, then it shouldn't be probed. 7-bit
 * addressing is assumed, 10-bit address devices are rare and should be
 * explicitly enumerated. */
885
static int i2c_check_7bit_addr_validity_strict(unsigned short addr)
886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901
{
	/*
	 * Reserved addresses per I2C specification:
	 *  0x00       General call address / START byte
	 *  0x01       CBUS address
	 *  0x02       Reserved for different bus format
	 *  0x03       Reserved for future purposes
	 *  0x04-0x07  Hs-mode master code
	 *  0x78-0x7b  10-bit slave addressing
	 *  0x7c-0x7f  Reserved for future purposes
	 */
	if (addr < 0x08 || addr > 0x77)
		return -EINVAL;
	return 0;
}

902 903 904 905 906
static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	int			addr = *(int *)addrp;

907
	if (client && i2c_encode_flags_to_addr(client) == addr)
908 909 910 911
		return -EBUSY;
	return 0;
}

912 913 914
/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
915
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
916 917 918 919 920
	int result;

	result = device_for_each_child(&adapter->dev, &addr,
					__i2c_check_addr_busy);

921 922
	if (!result && parent)
		result = i2c_check_mux_parents(parent, addr);
923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940

	return result;
}

/* recurse down mux tree */
static int i2c_check_mux_children(struct device *dev, void *addrp)
{
	int result;

	if (dev->type == &i2c_adapter_type)
		result = device_for_each_child(dev, addrp,
						i2c_check_mux_children);
	else
		result = __i2c_check_addr_busy(dev, addrp);

	return result;
}

941 942
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
943
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
944 945
	int result = 0;

946 947
	if (parent)
		result = i2c_check_mux_parents(parent, addr);
948 949 950 951 952 953

	if (!result)
		result = device_for_each_child(&adapter->dev, &addr,
						i2c_check_mux_children);

	return result;
954 955
}

956
/**
957
 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
958
 * @adapter: Target I2C bus segment
959 960
 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 *	locks only this branch in the adapter tree
961
 */
962 963
static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
				 unsigned int flags)
964
{
965 966 967 968
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)
		i2c_lock_adapter(parent);
969 970
	else
		rt_mutex_lock(&adapter->bus_lock);
971 972 973
}

/**
974
 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
975
 * @adapter: Target I2C bus segment
976 977
 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	trylocks only this branch in the adapter tree
978
 */
979 980
static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
981
{
982 983 984
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)
985
		return parent->trylock_bus(parent, flags);
986 987
	else
		return rt_mutex_trylock(&adapter->bus_lock);
988 989 990
}

/**
991
 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
992
 * @adapter: Target I2C bus segment
993 994
 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	unlocks only this branch in the adapter tree
995
 */
996 997
static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
998
{
999 1000 1001 1002
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);

	if (parent)
		i2c_unlock_adapter(parent);
1003 1004
	else
		rt_mutex_unlock(&adapter->bus_lock);
1005 1006
}

1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017
static void i2c_dev_set_name(struct i2c_adapter *adap,
			     struct i2c_client *client)
{
	struct acpi_device *adev = ACPI_COMPANION(&client->dev);

	if (adev) {
		dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
		return;
	}

	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
1018
		     i2c_encode_flags_to_addr(client));
1019 1020
}

1021
/**
1022
 * i2c_new_device - instantiate an i2c device
1023 1024
 * @adap: the adapter managing the device
 * @info: describes one I2C device; bus_num is ignored
D
David Brownell 已提交
1025
 * Context: can sleep
1026
 *
1027 1028 1029 1030 1031 1032
 * Create an i2c device. Binding is handled through driver model
 * probe()/remove() methods.  A driver may be bound to this device when we
 * return from this function, or any later moment (e.g. maybe hotplugging will
 * load the driver module).  This call is not appropriate for use by mainboard
 * initialization logic, which usually runs during an arch_initcall() long
 * before any i2c_adapter could exist.
1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049
 *
 * This returns the new i2c client, which may be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
struct i2c_client *
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
{
	struct i2c_client	*client;
	int			status;

	client = kzalloc(sizeof *client, GFP_KERNEL);
	if (!client)
		return NULL;

	client->adapter = adap;

	client->dev.platform_data = info->platform_data;
1050

A
Anton Vorontsov 已提交
1051 1052 1053
	if (info->archdata)
		client->dev.archdata = *info->archdata;

M
Marc Pignat 已提交
1054
	client->flags = info->flags;
1055 1056 1057 1058 1059
	client->addr = info->addr;
	client->irq = info->irq;

	strlcpy(client->name, info->type, sizeof(client->name));

1060
	status = i2c_check_addr_validity(client->addr, client->flags);
1061 1062 1063 1064 1065 1066
	if (status) {
		dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
			client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
		goto out_err_silent;
	}

1067
	/* Check for address business */
1068
	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
1069 1070 1071 1072 1073
	if (status)
		goto out_err;

	client->dev.parent = &client->adapter->dev;
	client->dev.bus = &i2c_bus_type;
1074
	client->dev.type = &i2c_client_type;
1075
	client->dev.of_node = info->of_node;
1076
	client->dev.fwnode = info->fwnode;
1077

1078
	i2c_dev_set_name(adap, client);
1079 1080 1081 1082 1083 1084 1085
	status = device_register(&client->dev);
	if (status)
		goto out_err;

	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
		client->name, dev_name(&client->dev));

1086
	return client;
1087 1088 1089 1090

out_err:
	dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
		"(%d)\n", client->name, client->addr, status);
1091
out_err_silent:
1092 1093
	kfree(client);
	return NULL;
1094 1095 1096 1097 1098 1099 1100
}
EXPORT_SYMBOL_GPL(i2c_new_device);


/**
 * i2c_unregister_device - reverse effect of i2c_new_device()
 * @client: value returned from i2c_new_device()
D
David Brownell 已提交
1101
 * Context: can sleep
1102 1103
 */
void i2c_unregister_device(struct i2c_client *client)
D
David Brownell 已提交
1104
{
1105 1106
	if (client->dev.of_node)
		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
D
David Brownell 已提交
1107 1108
	device_unregister(&client->dev);
}
1109
EXPORT_SYMBOL_GPL(i2c_unregister_device);
D
David Brownell 已提交
1110 1111


J
Jean Delvare 已提交
1112 1113 1114 1115 1116
static const struct i2c_device_id dummy_id[] = {
	{ "dummy", 0 },
	{ },
};

1117 1118 1119 1120 1121 1122 1123
static int dummy_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	return 0;
}

static int dummy_remove(struct i2c_client *client)
1124 1125 1126 1127 1128 1129
{
	return 0;
}

static struct i2c_driver dummy_driver = {
	.driver.name	= "dummy",
1130 1131
	.probe		= dummy_probe,
	.remove		= dummy_remove,
J
Jean Delvare 已提交
1132
	.id_table	= dummy_id,
1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152
};

/**
 * i2c_new_dummy - return a new i2c device bound to a dummy driver
 * @adapter: the adapter managing the device
 * @address: seven bit address to be used
 * Context: can sleep
 *
 * This returns an I2C client bound to the "dummy" driver, intended for use
 * with devices that consume multiple addresses.  Examples of such chips
 * include various EEPROMS (like 24c04 and 24c08 models).
 *
 * These dummy devices have two main uses.  First, most I2C and SMBus calls
 * except i2c_transfer() need a client handle; the dummy will be that handle.
 * And second, this prevents the specified address from being bound to a
 * different driver.
 *
 * This returns the new i2c client, which should be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
Z
Zhenwen Xu 已提交
1153
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
1154 1155
{
	struct i2c_board_info info = {
J
Jean Delvare 已提交
1156
		I2C_BOARD_INFO("dummy", address),
1157 1158 1159 1160 1161 1162
	};

	return i2c_new_device(adapter, &info);
}
EXPORT_SYMBOL_GPL(i2c_new_dummy);

1163 1164
/* ------------------------------------------------------------------------- */

D
David Brownell 已提交
1165 1166
/* I2C bus adapters -- one roots each I2C or SMBUS segment */

A
Adrian Bunk 已提交
1167
static void i2c_adapter_dev_release(struct device *dev)
L
Linus Torvalds 已提交
1168
{
1169
	struct i2c_adapter *adap = to_i2c_adapter(dev);
L
Linus Torvalds 已提交
1170 1171 1172
	complete(&adap->dev_released);
}

1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188
/*
 * This function is only needed for mutex_lock_nested, so it is never
 * called unless locking correctness checking is enabled. Thus we
 * make it inline to avoid a compiler warning. That's what gcc ends up
 * doing anyway.
 */
static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
{
	unsigned int depth = 0;

	while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
		depth++;

	return depth;
}

1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232
/*
 * Let users instantiate I2C devices through sysfs. This can be used when
 * platform initialization code doesn't contain the proper data for
 * whatever reason. Also useful for drivers that do device detection and
 * detection fails, either because the device uses an unexpected address,
 * or this is a compatible device with different ID register values.
 *
 * Parameter checking may look overzealous, but we really don't want
 * the user to provide incorrect parameters.
 */
static ssize_t
i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
		     const char *buf, size_t count)
{
	struct i2c_adapter *adap = to_i2c_adapter(dev);
	struct i2c_board_info info;
	struct i2c_client *client;
	char *blank, end;
	int res;

	memset(&info, 0, sizeof(struct i2c_board_info));

	blank = strchr(buf, ' ');
	if (!blank) {
		dev_err(dev, "%s: Missing parameters\n", "new_device");
		return -EINVAL;
	}
	if (blank - buf > I2C_NAME_SIZE - 1) {
		dev_err(dev, "%s: Invalid device name\n", "new_device");
		return -EINVAL;
	}
	memcpy(info.type, buf, blank - buf);

	/* Parse remaining parameters, reject extra parameters */
	res = sscanf(++blank, "%hi%c", &info.addr, &end);
	if (res < 1) {
		dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
		return -EINVAL;
	}
	if (res > 1  && end != '\n') {
		dev_err(dev, "%s: Extra parameters\n", "new_device");
		return -EINVAL;
	}

1233 1234 1235 1236 1237 1238 1239 1240 1241 1242
	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
		info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
		info.flags |= I2C_CLIENT_TEN;
	}

	if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
		info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
		info.flags |= I2C_CLIENT_SLAVE;
	}

1243 1244
	client = i2c_new_device(adap, &info);
	if (!client)
1245
		return -EINVAL;
1246 1247

	/* Keep track of the added device */
1248
	mutex_lock(&adap->userspace_clients_lock);
1249
	list_add_tail(&client->detected, &adap->userspace_clients);
1250
	mutex_unlock(&adap->userspace_clients_lock);
1251 1252 1253 1254 1255
	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
		 info.type, info.addr);

	return count;
}
1256
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289

/*
 * And of course let the users delete the devices they instantiated, if
 * they got it wrong. This interface can only be used to delete devices
 * instantiated by i2c_sysfs_new_device above. This guarantees that we
 * don't delete devices to which some kernel code still has references.
 *
 * Parameter checking may look overzealous, but we really don't want
 * the user to delete the wrong device.
 */
static ssize_t
i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
			const char *buf, size_t count)
{
	struct i2c_adapter *adap = to_i2c_adapter(dev);
	struct i2c_client *client, *next;
	unsigned short addr;
	char end;
	int res;

	/* Parse parameters, reject extra parameters */
	res = sscanf(buf, "%hi%c", &addr, &end);
	if (res < 1) {
		dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
		return -EINVAL;
	}
	if (res > 1  && end != '\n') {
		dev_err(dev, "%s: Extra parameters\n", "delete_device");
		return -EINVAL;
	}

	/* Make sure the device was added through sysfs */
	res = -ENOENT;
1290 1291
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1292 1293
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
1294
		if (i2c_encode_flags_to_addr(client) == addr) {
1295 1296 1297 1298 1299 1300 1301 1302 1303
			dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
				 "delete_device", client->name, client->addr);

			list_del(&client->detected);
			i2c_unregister_device(client);
			res = count;
			break;
		}
	}
1304
	mutex_unlock(&adap->userspace_clients_lock);
1305 1306 1307 1308 1309 1310

	if (res < 0)
		dev_err(dev, "%s: Can't find device in list\n",
			"delete_device");
	return res;
}
1311 1312
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
				   i2c_sysfs_delete_device);
1313 1314 1315 1316 1317 1318 1319

static struct attribute *i2c_adapter_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_new_device.attr,
	&dev_attr_delete_device.attr,
	NULL
};
1320
ATTRIBUTE_GROUPS(i2c_adapter);
1321

1322
struct device_type i2c_adapter_type = {
1323
	.groups		= i2c_adapter_groups,
1324
	.release	= i2c_adapter_dev_release,
L
Linus Torvalds 已提交
1325
};
1326
EXPORT_SYMBOL_GPL(i2c_adapter_type);
L
Linus Torvalds 已提交
1327

1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344
/**
 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
 * @dev: device, probably from some driver model iterator
 *
 * When traversing the driver model tree, perhaps using driver model
 * iterators like @device_for_each_child(), you can't assume very much
 * about the nodes you find.  Use this function to avoid oopses caused
 * by wrongly treating some non-I2C device as an i2c_adapter.
 */
struct i2c_adapter *i2c_verify_adapter(struct device *dev)
{
	return (dev->type == &i2c_adapter_type)
			? to_i2c_adapter(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_adapter);

1345 1346 1347 1348
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;
#endif

1349 1350 1351 1352
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
	struct i2c_devinfo	*devinfo;

1353
	down_read(&__i2c_board_lock);
1354 1355 1356 1357
	list_for_each_entry(devinfo, &__i2c_board_list, list) {
		if (devinfo->busnum == adapter->nr
				&& !i2c_new_device(adapter,
						&devinfo->board_info))
Z
Zhenwen Xu 已提交
1358 1359
			dev_err(&adapter->dev,
				"Can't create device at 0x%02x\n",
1360 1361
				devinfo->board_info.addr);
	}
1362
	up_read(&__i2c_board_lock);
1363 1364
}

1365 1366 1367
/* OF support code */

#if IS_ENABLED(CONFIG_OF)
1368 1369
static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
						 struct device_node *node)
1370
{
1371 1372 1373
	struct i2c_client *result;
	struct i2c_board_info info = {};
	struct dev_archdata dev_ad = {};
W
Wolfram Sang 已提交
1374 1375
	const __be32 *addr_be;
	u32 addr;
1376
	int len;
1377

1378
	dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1379

1380 1381 1382 1383 1384
	if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
		dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
			node->full_name);
		return ERR_PTR(-EINVAL);
	}
1385

W
Wolfram Sang 已提交
1386 1387
	addr_be = of_get_property(node, "reg", &len);
	if (!addr_be || (len < sizeof(*addr_be))) {
1388 1389 1390 1391
		dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
			node->full_name);
		return ERR_PTR(-EINVAL);
	}
1392

W
Wolfram Sang 已提交
1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404
	addr = be32_to_cpup(addr_be);
	if (addr & I2C_TEN_BIT_ADDRESS) {
		addr &= ~I2C_TEN_BIT_ADDRESS;
		info.flags |= I2C_CLIENT_TEN;
	}

	if (addr & I2C_OWN_SLAVE_ADDRESS) {
		addr &= ~I2C_OWN_SLAVE_ADDRESS;
		info.flags |= I2C_CLIENT_SLAVE;
	}

	if (i2c_check_addr_validity(addr, info.flags)) {
1405 1406 1407 1408
		dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
			info.addr, node->full_name);
		return ERR_PTR(-EINVAL);
	}
1409

W
Wolfram Sang 已提交
1410
	info.addr = addr;
1411 1412
	info.of_node = of_node_get(node);
	info.archdata = &dev_ad;
1413

1414 1415
	if (of_get_property(node, "wakeup-source", NULL))
		info.flags |= I2C_CLIENT_WAKE;
1416

1417 1418 1419 1420 1421 1422 1423 1424 1425
	result = i2c_new_device(adap, &info);
	if (result == NULL) {
		dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
			node->full_name);
		of_node_put(node);
		return ERR_PTR(-EINVAL);
	}
	return result;
}
1426

1427 1428 1429
static void of_i2c_register_devices(struct i2c_adapter *adap)
{
	struct device_node *node;
1430

1431 1432 1433
	/* Only register child devices if the adapter has a node pointer set */
	if (!adap->dev.of_node)
		return;
1434

1435 1436
	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");

1437 1438 1439
	for_each_available_child_of_node(adap->dev.of_node, node) {
		if (of_node_test_and_set_flag(node, OF_POPULATED))
			continue;
1440
		of_i2c_register_device(adap, node);
1441
	}
1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452
}

static int of_dev_node_match(struct device *dev, void *data)
{
	return dev->of_node == data;
}

/* must call put_device() when done with returned i2c_client device */
struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
{
	struct device *dev;
1453
	struct i2c_client *client;
1454

1455
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1456 1457 1458
	if (!dev)
		return NULL;

1459 1460 1461 1462 1463
	client = i2c_verify_client(dev);
	if (!client)
		put_device(dev);

	return client;
1464 1465 1466 1467 1468 1469 1470
}
EXPORT_SYMBOL(of_find_i2c_device_by_node);

/* must call put_device() when done with returned i2c_adapter device */
struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
{
	struct device *dev;
1471
	struct i2c_adapter *adapter;
1472

1473
	dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1474 1475 1476
	if (!dev)
		return NULL;

1477 1478 1479 1480 1481
	adapter = i2c_verify_adapter(dev);
	if (!adapter)
		put_device(dev);

	return adapter;
1482 1483
}
EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501

/* must call i2c_put_adapter() when done with returned i2c_adapter device */
struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
{
	struct i2c_adapter *adapter;

	adapter = of_find_i2c_adapter_by_node(node);
	if (!adapter)
		return NULL;

	if (!try_module_get(adapter->owner)) {
		put_device(&adapter->dev);
		adapter = NULL;
	}

	return adapter;
}
EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
1502 1503 1504 1505
#else
static void of_i2c_register_devices(struct i2c_adapter *adap) { }
#endif /* CONFIG_OF */

J
Jean Delvare 已提交
1506 1507
static int i2c_do_add_adapter(struct i2c_driver *driver,
			      struct i2c_adapter *adap)
1508
{
1509 1510 1511 1512
	/* Detect supported devices on that bus, and instantiate them */
	i2c_detect(adap, driver);

	/* Let legacy drivers scan this bus for matching devices */
1513
	if (driver->attach_adapter) {
J
Jean Delvare 已提交
1514 1515
		dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
			 driver->driver.name);
1516 1517
		dev_warn(&adap->dev, "Please use another way to instantiate "
			 "your i2c_client\n");
1518 1519 1520 1521 1522 1523
		/* We ignore the return code; if it fails, too bad */
		driver->attach_adapter(adap);
	}
	return 0;
}

J
Jean Delvare 已提交
1524 1525 1526 1527 1528
static int __process_new_adapter(struct device_driver *d, void *data)
{
	return i2c_do_add_adapter(to_i2c_driver(d), data);
}

1529
static int i2c_register_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1530
{
J
Jean Delvare 已提交
1531
	int res = 0;
L
Linus Torvalds 已提交
1532

1533
	/* Can't register until after driver model init */
1534
	if (WARN_ON(!is_registered)) {
1535 1536 1537
		res = -EAGAIN;
		goto out_list;
	}
1538

1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550
	/* Sanity checks */
	if (unlikely(adap->name[0] == '\0')) {
		pr_err("i2c-core: Attempt to register an adapter with "
		       "no name!\n");
		return -EINVAL;
	}
	if (unlikely(!adap->algo)) {
		pr_err("i2c-core: Attempt to register adapter '%s' with "
		       "no algo!\n", adap->name);
		return -EINVAL;
	}

1551 1552 1553 1554 1555 1556
	if (!adap->lock_bus) {
		adap->lock_bus = i2c_adapter_lock_bus;
		adap->trylock_bus = i2c_adapter_trylock_bus;
		adap->unlock_bus = i2c_adapter_unlock_bus;
	}

1557
	rt_mutex_init(&adap->bus_lock);
1558
	mutex_init(&adap->userspace_clients_lock);
1559
	INIT_LIST_HEAD(&adap->userspace_clients);
L
Linus Torvalds 已提交
1560

1561 1562 1563 1564
	/* Set default timeout to 1 second if not already set */
	if (adap->timeout == 0)
		adap->timeout = HZ;

1565
	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1566 1567
	adap->dev.bus = &i2c_bus_type;
	adap->dev.type = &i2c_adapter_type;
1568 1569 1570
	res = device_register(&adap->dev);
	if (res)
		goto out_list;
L
Linus Torvalds 已提交
1571

1572 1573
	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

1574
	pm_runtime_no_callbacks(&adap->dev);
1575
	pm_suspend_ignore_children(&adap->dev, true);
1576
	pm_runtime_enable(&adap->dev);
1577

1578 1579 1580 1581 1582 1583 1584 1585
#ifdef CONFIG_I2C_COMPAT
	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
				       adap->dev.parent);
	if (res)
		dev_warn(&adap->dev,
			 "Failed to create compatibility class link\n");
#endif

1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618
	/* bus recovery specific initialization */
	if (adap->bus_recovery_info) {
		struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;

		if (!bri->recover_bus) {
			dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
			adap->bus_recovery_info = NULL;
			goto exit_recovery;
		}

		/* Generic GPIO recovery */
		if (bri->recover_bus == i2c_generic_gpio_recovery) {
			if (!gpio_is_valid(bri->scl_gpio)) {
				dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
				adap->bus_recovery_info = NULL;
				goto exit_recovery;
			}

			if (gpio_is_valid(bri->sda_gpio))
				bri->get_sda = get_sda_gpio_value;
			else
				bri->get_sda = NULL;

			bri->get_scl = get_scl_gpio_value;
			bri->set_scl = set_scl_gpio_value;
		} else if (!bri->set_scl || !bri->get_scl) {
			/* Generic SCL recovery */
			dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
			adap->bus_recovery_info = NULL;
		}
	}

exit_recovery:
1619
	/* create pre-declared device nodes */
1620
	of_i2c_register_devices(adap);
1621
	acpi_i2c_register_devices(adap);
1622
	acpi_i2c_install_space_handler(adap);
1623

1624 1625 1626
	if (adap->nr < __i2c_first_dynamic_bus_num)
		i2c_scan_static_board_info(adap);

1627
	/* Notify drivers */
1628
	mutex_lock(&core_lock);
J
Jean Delvare 已提交
1629
	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
J
Jean Delvare 已提交
1630
	mutex_unlock(&core_lock);
1631 1632

	return 0;
1633 1634

out_list:
1635
	mutex_lock(&core_lock);
1636
	idr_remove(&i2c_adapter_idr, adap->nr);
1637 1638
	mutex_unlock(&core_lock);
	return res;
L
Linus Torvalds 已提交
1639 1640
}

1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661
/**
 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
 * @adap: the adapter to register (with adap->nr initialized)
 * Context: can sleep
 *
 * See i2c_add_numbered_adapter() for details.
 */
static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
	int	id;

	mutex_lock(&core_lock);
	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
		       GFP_KERNEL);
	mutex_unlock(&core_lock);
	if (id < 0)
		return id == -ENOSPC ? -EBUSY : id;

	return i2c_register_adapter(adap);
}

1662 1663 1664
/**
 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
 * @adapter: the adapter to add
D
David Brownell 已提交
1665
 * Context: can sleep
1666 1667
 *
 * This routine is used to declare an I2C adapter when its bus number
1668 1669 1670
 * doesn't matter or when its bus number is specified by an dt alias.
 * Examples of bases when the bus number doesn't matter: I2C adapters
 * dynamically added by USB links or PCI plugin cards.
1671 1672 1673 1674 1675 1676 1677
 *
 * When this returns zero, a new bus number was allocated and stored
 * in adap->nr, and the specified adapter became available for clients.
 * Otherwise, a negative errno value is returned.
 */
int i2c_add_adapter(struct i2c_adapter *adapter)
{
1678
	struct device *dev = &adapter->dev;
T
Tejun Heo 已提交
1679
	int id;
1680

1681 1682 1683 1684 1685 1686 1687 1688
	if (dev->of_node) {
		id = of_alias_get_id(dev->of_node, "i2c");
		if (id >= 0) {
			adapter->nr = id;
			return __i2c_add_numbered_adapter(adapter);
		}
	}

J
Jean Delvare 已提交
1689
	mutex_lock(&core_lock);
T
Tejun Heo 已提交
1690 1691
	id = idr_alloc(&i2c_adapter_idr, adapter,
		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
J
Jean Delvare 已提交
1692
	mutex_unlock(&core_lock);
T
Tejun Heo 已提交
1693 1694
	if (id < 0)
		return id;
1695 1696

	adapter->nr = id;
T
Tejun Heo 已提交
1697

1698 1699 1700 1701 1702 1703 1704
	return i2c_register_adapter(adapter);
}
EXPORT_SYMBOL(i2c_add_adapter);

/**
 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
 * @adap: the adapter to register (with adap->nr initialized)
D
David Brownell 已提交
1705
 * Context: can sleep
1706 1707
 *
 * This routine is used to declare an I2C adapter when its bus number
R
Randy Dunlap 已提交
1708 1709
 * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
 * or otherwise built in to the system's mainboard, and where i2c_board_info
1710 1711
 * is used to properly configure I2C devices.
 *
1712 1713 1714
 * If the requested bus number is set to -1, then this function will behave
 * identically to i2c_add_adapter, and will dynamically assign a bus number.
 *
1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726
 * If no devices have pre-been declared for this bus, then be sure to
 * register the adapter before any dynamically allocated ones.  Otherwise
 * the required bus ID may not be available.
 *
 * When this returns zero, the specified adapter became available for
 * clients using the bus number provided in adap->nr.  Also, the table
 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
 * and the appropriate driver model device nodes are created.  Otherwise, a
 * negative errno value is returned.
 */
int i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
1727 1728
	if (adap->nr == -1) /* -1 means dynamically assign bus id */
		return i2c_add_adapter(adap);
1729

1730
	return __i2c_add_numbered_adapter(adap);
1731 1732 1733
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);

L
Lars-Peter Clausen 已提交
1734
static void i2c_do_del_adapter(struct i2c_driver *driver,
J
Jean Delvare 已提交
1735
			      struct i2c_adapter *adapter)
1736
{
1737
	struct i2c_client *client, *_n;
1738

1739 1740
	/* Remove the devices we created ourselves as the result of hardware
	 * probing (using a driver's detect method) */
1741 1742 1743 1744 1745 1746 1747 1748
	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
		if (client->adapter == adapter) {
			dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
				client->name, client->addr);
			list_del(&client->detected);
			i2c_unregister_device(client);
		}
	}
1749 1750
}

1751
static int __unregister_client(struct device *dev, void *dummy)
1752 1753 1754 1755 1756 1757 1758 1759
{
	struct i2c_client *client = i2c_verify_client(dev);
	if (client && strcmp(client->name, "dummy"))
		i2c_unregister_device(client);
	return 0;
}

static int __unregister_dummy(struct device *dev, void *dummy)
1760 1761 1762 1763 1764 1765 1766
{
	struct i2c_client *client = i2c_verify_client(dev);
	if (client)
		i2c_unregister_device(client);
	return 0;
}

J
Jean Delvare 已提交
1767 1768
static int __process_removed_adapter(struct device_driver *d, void *data)
{
L
Lars-Peter Clausen 已提交
1769 1770
	i2c_do_del_adapter(to_i2c_driver(d), data);
	return 0;
J
Jean Delvare 已提交
1771 1772
}

D
David Brownell 已提交
1773 1774 1775 1776 1777 1778 1779 1780
/**
 * i2c_del_adapter - unregister I2C adapter
 * @adap: the adapter being unregistered
 * Context: can sleep
 *
 * This unregisters an I2C adapter which was previously registered
 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
 */
1781
void i2c_del_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1782
{
1783
	struct i2c_adapter *found;
1784
	struct i2c_client *client, *next;
L
Linus Torvalds 已提交
1785 1786

	/* First make sure that this adapter was ever added */
1787 1788 1789 1790
	mutex_lock(&core_lock);
	found = idr_find(&i2c_adapter_idr, adap->nr);
	mutex_unlock(&core_lock);
	if (found != adap) {
1791 1792
		pr_debug("i2c-core: attempting to delete unregistered "
			 "adapter [%s]\n", adap->name);
1793
		return;
L
Linus Torvalds 已提交
1794 1795
	}

1796
	acpi_i2c_remove_space_handler(adap);
1797
	/* Tell drivers about this removal */
1798
	mutex_lock(&core_lock);
L
Lars-Peter Clausen 已提交
1799
	bus_for_each_drv(&i2c_bus_type, NULL, adap,
J
Jean Delvare 已提交
1800
			       __process_removed_adapter);
1801
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1802

1803
	/* Remove devices instantiated from sysfs */
1804 1805
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1806 1807 1808 1809 1810 1811
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
			client->addr);
		list_del(&client->detected);
		i2c_unregister_device(client);
1812
	}
1813
	mutex_unlock(&adap->userspace_clients_lock);
1814

1815
	/* Detach any active clients. This can't fail, thus we do not
1816 1817 1818 1819
	 * check the returned value. This is a two-pass process, because
	 * we can't remove the dummy devices during the first pass: they
	 * could have been instantiated by real devices wishing to clean
	 * them up properly, so we give them a chance to do that first. */
L
Lars-Peter Clausen 已提交
1820 1821
	device_for_each_child(&adap->dev, NULL, __unregister_client);
	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
L
Linus Torvalds 已提交
1822

1823 1824 1825 1826 1827
#ifdef CONFIG_I2C_COMPAT
	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
				 adap->dev.parent);
#endif

1828 1829 1830
	/* device name is gone after device_unregister */
	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);

1831 1832
	pm_runtime_disable(&adap->dev);

1833 1834 1835 1836 1837
	/* wait until all references to the device are gone
	 *
	 * FIXME: This is old code and should ideally be replaced by an
	 * alternative which results in decoupling the lifetime of the struct
	 * device from the i2c_adapter, like spi or netdev do. Any solution
1838
	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1839
	 */
L
Linus Torvalds 已提交
1840 1841 1842 1843
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);

1844
	/* free bus id */
1845
	mutex_lock(&core_lock);
L
Linus Torvalds 已提交
1846
	idr_remove(&i2c_adapter_idr, adap->nr);
1847
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1848

1849 1850 1851
	/* Clear the device structure in case this adapter is ever going to be
	   added again */
	memset(&adap->dev, 0, sizeof(adap->dev));
L
Linus Torvalds 已提交
1852
}
D
David Brownell 已提交
1853
EXPORT_SYMBOL(i2c_del_adapter);
L
Linus Torvalds 已提交
1854

1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906
/**
 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
 * @dev: The device to scan for I2C timing properties
 * @t: the i2c_timings struct to be filled with values
 * @use_defaults: bool to use sane defaults derived from the I2C specification
 *		  when properties are not found, otherwise use 0
 *
 * Scan the device for the generic I2C properties describing timing parameters
 * for the signal and fill the given struct with the results. If a property was
 * not found and use_defaults was true, then maximum timings are assumed which
 * are derived from the I2C specification. If use_defaults is not used, the
 * results will be 0, so drivers can apply their own defaults later. The latter
 * is mainly intended for avoiding regressions of existing drivers which want
 * to switch to this function. New drivers almost always should use the defaults.
 */

void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
{
	int ret;

	memset(t, 0, sizeof(*t));

	ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
	if (ret && use_defaults)
		t->bus_freq_hz = 100000;

	ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
	if (ret && use_defaults) {
		if (t->bus_freq_hz <= 100000)
			t->scl_rise_ns = 1000;
		else if (t->bus_freq_hz <= 400000)
			t->scl_rise_ns = 300;
		else
			t->scl_rise_ns = 120;
	}

	ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
	if (ret && use_defaults) {
		if (t->bus_freq_hz <= 400000)
			t->scl_fall_ns = 300;
		else
			t->scl_fall_ns = 120;
	}

	device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);

	ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
	if (ret && use_defaults)
		t->sda_fall_ns = t->scl_fall_ns;
}
EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);

D
David Brownell 已提交
1907 1908
/* ------------------------------------------------------------------------- */

J
Jean Delvare 已提交
1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920
int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
{
	int res;

	mutex_lock(&core_lock);
	res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
	mutex_unlock(&core_lock);

	return res;
}
EXPORT_SYMBOL_GPL(i2c_for_each_dev);

J
Jean Delvare 已提交
1921
static int __process_new_driver(struct device *dev, void *data)
D
Dave Young 已提交
1922
{
1923 1924
	if (dev->type != &i2c_adapter_type)
		return 0;
J
Jean Delvare 已提交
1925
	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
D
Dave Young 已提交
1926 1927
}

D
David Brownell 已提交
1928 1929
/*
 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1930
 * i2c slave chips, on a bus instance associated with some i2c_adapter.
L
Linus Torvalds 已提交
1931 1932
 */

1933
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
L
Linus Torvalds 已提交
1934
{
1935
	int res;
L
Linus Torvalds 已提交
1936

1937
	/* Can't register until after driver model init */
1938
	if (WARN_ON(!is_registered))
1939 1940
		return -EAGAIN;

L
Linus Torvalds 已提交
1941
	/* add the driver to the list of i2c drivers in the driver core */
1942
	driver->driver.owner = owner;
L
Linus Torvalds 已提交
1943 1944
	driver->driver.bus = &i2c_bus_type;

1945
	/* When registration returns, the driver core
1946 1947
	 * will have called probe() for all matching-but-unbound devices.
	 */
L
Linus Torvalds 已提交
1948 1949
	res = driver_register(&driver->driver);
	if (res)
1950
		return res;
D
David Brownell 已提交
1951

1952
	pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
L
Linus Torvalds 已提交
1953

1954 1955
	INIT_LIST_HEAD(&driver->clients);
	/* Walk the adapters that are already present */
J
Jean Delvare 已提交
1956
	i2c_for_each_dev(driver, __process_new_driver);
1957

D
Dave Young 已提交
1958 1959 1960 1961
	return 0;
}
EXPORT_SYMBOL(i2c_register_driver);

J
Jean Delvare 已提交
1962
static int __process_removed_driver(struct device *dev, void *data)
D
Dave Young 已提交
1963
{
L
Lars-Peter Clausen 已提交
1964 1965 1966
	if (dev->type == &i2c_adapter_type)
		i2c_do_del_adapter(data, to_i2c_adapter(dev));
	return 0;
L
Linus Torvalds 已提交
1967 1968
}

D
David Brownell 已提交
1969 1970 1971
/**
 * i2c_del_driver - unregister I2C driver
 * @driver: the driver being unregistered
D
David Brownell 已提交
1972
 * Context: can sleep
D
David Brownell 已提交
1973
 */
1974
void i2c_del_driver(struct i2c_driver *driver)
L
Linus Torvalds 已提交
1975
{
J
Jean Delvare 已提交
1976
	i2c_for_each_dev(driver, __process_removed_driver);
L
Linus Torvalds 已提交
1977 1978

	driver_unregister(&driver->driver);
1979
	pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
L
Linus Torvalds 已提交
1980
}
D
David Brownell 已提交
1981
EXPORT_SYMBOL(i2c_del_driver);
L
Linus Torvalds 已提交
1982

D
David Brownell 已提交
1983 1984
/* ------------------------------------------------------------------------- */

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996
/**
 * i2c_use_client - increments the reference count of the i2c client structure
 * @client: the client being referenced
 *
 * Each live reference to a client should be refcounted. The driver model does
 * that automatically as part of driver binding, so that most drivers don't
 * need to do this explicitly: they hold a reference until they're unbound
 * from the device.
 *
 * A pointer to the client with the incremented reference counter is returned.
 */
struct i2c_client *i2c_use_client(struct i2c_client *client)
L
Linus Torvalds 已提交
1997
{
1998 1999 2000
	if (client && get_device(&client->dev))
		return client;
	return NULL;
L
Linus Torvalds 已提交
2001
}
D
David Brownell 已提交
2002
EXPORT_SYMBOL(i2c_use_client);
L
Linus Torvalds 已提交
2003

2004 2005 2006 2007 2008 2009 2010
/**
 * i2c_release_client - release a use of the i2c client structure
 * @client: the client being no longer referenced
 *
 * Must be called when a user of a client is finished with it.
 */
void i2c_release_client(struct i2c_client *client)
L
Linus Torvalds 已提交
2011
{
2012 2013
	if (client)
		put_device(&client->dev);
L
Linus Torvalds 已提交
2014
}
D
David Brownell 已提交
2015
EXPORT_SYMBOL(i2c_release_client);
L
Linus Torvalds 已提交
2016

2017 2018 2019 2020 2021 2022 2023 2024 2025
struct i2c_cmd_arg {
	unsigned	cmd;
	void		*arg;
};

static int i2c_cmd(struct device *dev, void *_arg)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_cmd_arg	*arg = _arg;
2026 2027 2028 2029
	struct i2c_driver	*driver;

	if (!client || !client->dev.driver)
		return 0;
2030

2031 2032 2033
	driver = to_i2c_driver(client->dev.driver);
	if (driver->command)
		driver->command(client, arg->cmd, arg->arg);
2034 2035 2036
	return 0;
}

L
Linus Torvalds 已提交
2037 2038
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
{
2039
	struct i2c_cmd_arg	cmd_arg;
L
Linus Torvalds 已提交
2040

2041 2042 2043
	cmd_arg.cmd = cmd;
	cmd_arg.arg = arg;
	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
L
Linus Torvalds 已提交
2044
}
D
David Brownell 已提交
2045
EXPORT_SYMBOL(i2c_clients_command);
L
Linus Torvalds 已提交
2046

2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
			 void *arg)
{
	struct of_reconfig_data *rd = arg;
	struct i2c_adapter *adap;
	struct i2c_client *client;

	switch (of_reconfig_get_state_change(action, rd)) {
	case OF_RECONFIG_CHANGE_ADD:
		adap = of_find_i2c_adapter_by_node(rd->dn->parent);
		if (adap == NULL)
			return NOTIFY_OK;	/* not for us */

2061 2062 2063 2064 2065
		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
			put_device(&adap->dev);
			return NOTIFY_OK;
		}

2066 2067 2068 2069 2070 2071 2072 2073 2074 2075
		client = of_i2c_register_device(adap, rd->dn);
		put_device(&adap->dev);

		if (IS_ERR(client)) {
			pr_err("%s: failed to create for '%s'\n",
					__func__, rd->dn->full_name);
			return notifier_from_errno(PTR_ERR(client));
		}
		break;
	case OF_RECONFIG_CHANGE_REMOVE:
2076 2077 2078 2079
		/* already depopulated? */
		if (!of_node_check_flag(rd->dn, OF_POPULATED))
			return NOTIFY_OK;

2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101
		/* find our device by node */
		client = of_find_i2c_device_by_node(rd->dn);
		if (client == NULL)
			return NOTIFY_OK;	/* no? not meant for us */

		/* unregister takes one ref away */
		i2c_unregister_device(client);

		/* and put the reference of the find */
		put_device(&client->dev);
		break;
	}

	return NOTIFY_OK;
}
static struct notifier_block i2c_of_notifier = {
	.notifier_call = of_i2c_notify,
};
#else
extern struct notifier_block i2c_of_notifier;
#endif /* CONFIG_OF_DYNAMIC */

L
Linus Torvalds 已提交
2102 2103 2104 2105
static int __init i2c_init(void)
{
	int retval;

2106 2107 2108 2109 2110 2111 2112
	retval = of_alias_get_highest_id("i2c");

	down_write(&__i2c_board_lock);
	if (retval >= __i2c_first_dynamic_bus_num)
		__i2c_first_dynamic_bus_num = retval + 1;
	up_write(&__i2c_board_lock);

L
Linus Torvalds 已提交
2113 2114 2115
	retval = bus_register(&i2c_bus_type);
	if (retval)
		return retval;
2116 2117 2118

	is_registered = true;

2119 2120 2121 2122 2123 2124 2125
#ifdef CONFIG_I2C_COMPAT
	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
	if (!i2c_adapter_compat_class) {
		retval = -ENOMEM;
		goto bus_err;
	}
#endif
2126 2127
	retval = i2c_add_driver(&dummy_driver);
	if (retval)
2128
		goto class_err;
2129 2130 2131 2132

	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));

2133 2134
	return 0;

2135 2136 2137
class_err:
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
2138
bus_err:
2139
#endif
2140
	is_registered = false;
2141 2142
	bus_unregister(&i2c_bus_type);
	return retval;
L
Linus Torvalds 已提交
2143 2144 2145 2146
}

static void __exit i2c_exit(void)
{
2147 2148
	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2149
	i2c_del_driver(&dummy_driver);
2150 2151 2152
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
#endif
L
Linus Torvalds 已提交
2153
	bus_unregister(&i2c_bus_type);
2154
	tracepoint_synchronize_unregister();
L
Linus Torvalds 已提交
2155 2156
}

D
David Brownell 已提交
2157 2158 2159 2160
/* We must initialize early, because some subsystems register i2c drivers
 * in subsys_initcall() code, but are linked (and initialized) before i2c.
 */
postcore_initcall(i2c_init);
L
Linus Torvalds 已提交
2161 2162 2163 2164 2165 2166 2167
module_exit(i2c_exit);

/* ----------------------------------------------------
 * the functional interface to the i2c busses.
 * ----------------------------------------------------
 */

W
Wolfram Sang 已提交
2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226
/* Check if val is exceeding the quirk IFF quirk is non 0 */
#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))

static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
{
	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
			    err_msg, msg->addr, msg->len,
			    msg->flags & I2C_M_RD ? "read" : "write");
	return -EOPNOTSUPP;
}

static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	const struct i2c_adapter_quirks *q = adap->quirks;
	int max_num = q->max_num_msgs, i;
	bool do_len_check = true;

	if (q->flags & I2C_AQ_COMB) {
		max_num = 2;

		/* special checks for combined messages */
		if (num == 2) {
			if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
				return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");

			if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
				return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");

			if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
				return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");

			if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
				return i2c_quirk_error(adap, &msgs[0], "msg too long");

			if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
				return i2c_quirk_error(adap, &msgs[1], "msg too long");

			do_len_check = false;
		}
	}

	if (i2c_quirk_exceeded(num, max_num))
		return i2c_quirk_error(adap, &msgs[0], "too many messages");

	for (i = 0; i < num; i++) {
		u16 len = msgs[i].len;

		if (msgs[i].flags & I2C_M_RD) {
			if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
				return i2c_quirk_error(adap, &msgs[i], "msg too long");
		} else {
			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
				return i2c_quirk_error(adap, &msgs[i], "msg too long");
		}
	}

	return 0;
}

2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243
/**
 * __i2c_transfer - unlocked flavor of i2c_transfer
 * @adap: Handle to I2C bus
 * @msgs: One or more messages to execute before STOP is issued to
 *	terminate the operation; each message begins with a START.
 * @num: Number of messages to be executed.
 *
 * Returns negative errno, else the number of messages executed.
 *
 * Adapter lock must be held when calling this function. No debug logging
 * takes place. adap->algo->master_xfer existence isn't checked.
 */
int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	unsigned long orig_jiffies;
	int ret, try;

W
Wolfram Sang 已提交
2244 2245 2246
	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
		return -EOPNOTSUPP;

2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259
	/* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
	 * enabled.  This is an efficient way of keeping the for-loop from
	 * being executed when not needed.
	 */
	if (static_key_false(&i2c_trace_msg)) {
		int i;
		for (i = 0; i < num; i++)
			if (msgs[i].flags & I2C_M_RD)
				trace_i2c_read(adap, &msgs[i], i);
			else
				trace_i2c_write(adap, &msgs[i], i);
	}

2260 2261 2262 2263 2264 2265 2266 2267 2268 2269
	/* Retry automatically on arbitration loss */
	orig_jiffies = jiffies;
	for (ret = 0, try = 0; try <= adap->retries; try++) {
		ret = adap->algo->master_xfer(adap, msgs, num);
		if (ret != -EAGAIN)
			break;
		if (time_after(jiffies, orig_jiffies + adap->timeout))
			break;
	}

2270 2271 2272 2273 2274 2275 2276 2277
	if (static_key_false(&i2c_trace_msg)) {
		int i;
		for (i = 0; i < ret; i++)
			if (msgs[i].flags & I2C_M_RD)
				trace_i2c_reply(adap, &msgs[i], i);
		trace_i2c_result(adap, i, ret);
	}

2278 2279 2280 2281
	return ret;
}
EXPORT_SYMBOL(__i2c_transfer);

2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293
/**
 * i2c_transfer - execute a single or combined I2C message
 * @adap: Handle to I2C bus
 * @msgs: One or more messages to execute before STOP is issued to
 *	terminate the operation; each message begins with a START.
 * @num: Number of messages to be executed.
 *
 * Returns negative errno, else the number of messages executed.
 *
 * Note that there is no requirement that each message be sent to
 * the same slave address, although that is the most common model.
 */
Z
Zhenwen Xu 已提交
2294
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
L
Linus Torvalds 已提交
2295
{
2296
	int ret;
L
Linus Torvalds 已提交
2297

2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314
	/* REVISIT the fault reporting model here is weak:
	 *
	 *  - When we get an error after receiving N bytes from a slave,
	 *    there is no way to report "N".
	 *
	 *  - When we get a NAK after transmitting N bytes to a slave,
	 *    there is no way to report "N" ... or to let the master
	 *    continue executing the rest of this combined message, if
	 *    that's the appropriate response.
	 *
	 *  - When for example "num" is two and we successfully complete
	 *    the first message but get an error part way through the
	 *    second, it's unclear whether that should be reported as
	 *    one (discarding status on the second message) or errno
	 *    (discarding status on the first one).
	 */

L
Linus Torvalds 已提交
2315 2316 2317 2318
	if (adap->algo->master_xfer) {
#ifdef DEBUG
		for (ret = 0; ret < num; ret++) {
			dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
2319 2320 2321
				"len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
				? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
				(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
L
Linus Torvalds 已提交
2322 2323 2324
		}
#endif

2325
		if (in_atomic() || irqs_disabled()) {
2326
			ret = adap->trylock_bus(adap, I2C_LOCK_SEGMENT);
2327 2328 2329 2330
			if (!ret)
				/* I2C activity is ongoing. */
				return -EAGAIN;
		} else {
2331
			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
2332 2333
		}

2334
		ret = __i2c_transfer(adap, msgs, num);
2335
		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
2336 2337 2338 2339

		return ret;
	} else {
		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
D
David Brownell 已提交
2340
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
2341 2342
	}
}
D
David Brownell 已提交
2343
EXPORT_SYMBOL(i2c_transfer);
L
Linus Torvalds 已提交
2344

2345 2346 2347 2348
/**
 * i2c_master_send - issue a single I2C message in master transmit mode
 * @client: Handle to slave device
 * @buf: Data that will be written to the slave
2349
 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2350 2351 2352
 *
 * Returns negative errno, or else the number of bytes written.
 */
2353
int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
L
Linus Torvalds 已提交
2354 2355
{
	int ret;
2356
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2357 2358
	struct i2c_msg msg;

2359 2360 2361 2362
	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.len = count;
	msg.buf = (char *)buf;
D
David Brownell 已提交
2363

2364
	ret = i2c_transfer(adap, &msg, 1);
L
Linus Torvalds 已提交
2365

2366 2367 2368 2369
	/*
	 * If everything went ok (i.e. 1 msg transmitted), return #bytes
	 * transmitted, else error code.
	 */
2370
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2371
}
D
David Brownell 已提交
2372
EXPORT_SYMBOL(i2c_master_send);
L
Linus Torvalds 已提交
2373

2374 2375 2376 2377
/**
 * i2c_master_recv - issue a single I2C message in master receive mode
 * @client: Handle to slave device
 * @buf: Where to store data read from slave
2378
 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2379 2380 2381
 *
 * Returns negative errno, or else the number of bytes read.
 */
2382
int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
L
Linus Torvalds 已提交
2383
{
2384
	struct i2c_adapter *adap = client->adapter;
L
Linus Torvalds 已提交
2385 2386
	struct i2c_msg msg;
	int ret;
2387 2388 2389 2390 2391 2392 2393 2394 2395

	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.flags |= I2C_M_RD;
	msg.len = count;
	msg.buf = buf;

	ret = i2c_transfer(adap, &msg, 1);

2396 2397 2398 2399
	/*
	 * If everything went ok (i.e. 1 msg received), return #bytes received,
	 * else error code.
	 */
2400
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2401
}
D
David Brownell 已提交
2402
EXPORT_SYMBOL(i2c_master_recv);
L
Linus Torvalds 已提交
2403 2404 2405 2406 2407 2408 2409

/* ----------------------------------------------------
 * the i2c address scanning function
 * Will not work for 10-bit addresses!
 * ----------------------------------------------------
 */

2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433
/*
 * Legacy default probe function, mostly relevant for SMBus. The default
 * probe method is a quick write, but it is known to corrupt the 24RF08
 * EEPROMs due to a state machine bug, and could also irreversibly
 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
 * we use a short byte read instead. Also, some bus drivers don't implement
 * quick write, so we fallback to a byte read in that case too.
 * On x86, there is another special case for FSC hardware monitoring chips,
 * which want regular byte reads (address 0x73.) Fortunately, these are the
 * only known chips using this I2C address on PC hardware.
 * Returns 1 if probe succeeded, 0 if not.
 */
static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
{
	int err;
	union i2c_smbus_data dummy;

#ifdef CONFIG_X86
	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
				     I2C_SMBUS_BYTE_DATA, &dummy);
	else
#endif
2434 2435
	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2436 2437
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
				     I2C_SMBUS_QUICK, NULL);
2438 2439 2440 2441
	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
				     I2C_SMBUS_BYTE, &dummy);
	else {
2442 2443
		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
			 addr);
2444 2445
		err = -EOPNOTSUPP;
	}
2446 2447 2448 2449

	return err >= 0;
}

J
Jean Delvare 已提交
2450
static int i2c_detect_address(struct i2c_client *temp_client,
2451 2452 2453 2454 2455 2456 2457 2458
			      struct i2c_driver *driver)
{
	struct i2c_board_info info;
	struct i2c_adapter *adapter = temp_client->adapter;
	int addr = temp_client->addr;
	int err;

	/* Make sure the address is valid */
2459
	err = i2c_check_7bit_addr_validity_strict(addr);
2460
	if (err) {
2461 2462
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
			 addr);
2463
		return err;
2464 2465
	}

2466
	/* Skip if already in use (7 bit, no need to encode flags) */
2467
	if (i2c_check_addr_busy(adapter, addr))
2468 2469
		return 0;

J
Jean Delvare 已提交
2470
	/* Make sure there is something at this address */
2471 2472
	if (!i2c_default_probe(adapter, addr))
		return 0;
2473 2474 2475 2476

	/* Finally call the custom detection function */
	memset(&info, 0, sizeof(struct i2c_board_info));
	info.addr = addr;
2477
	err = driver->detect(temp_client, &info);
2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492
	if (err) {
		/* -ENODEV is returned if the detection fails. We catch it
		   here as this isn't an error. */
		return err == -ENODEV ? 0 : err;
	}

	/* Consistency check */
	if (info.type[0] == '\0') {
		dev_err(&adapter->dev, "%s detection function provided "
			"no name for 0x%x\n", driver->driver.name,
			addr);
	} else {
		struct i2c_client *client;

		/* Detection succeeded, instantiate the device */
2493 2494 2495 2496 2497 2498 2499
		if (adapter->class & I2C_CLASS_DEPRECATED)
			dev_warn(&adapter->dev,
				"This adapter will soon drop class based instantiation of devices. "
				"Please make sure client 0x%02x gets instantiated by other means. "
				"Check 'Documentation/i2c/instantiating-devices' for details.\n",
				info.addr);

2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513
		dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
			info.type, info.addr);
		client = i2c_new_device(adapter, &info);
		if (client)
			list_add_tail(&client->detected, &driver->clients);
		else
			dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
				info.type, info.addr);
	}
	return 0;
}

static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
{
2514
	const unsigned short *address_list;
2515 2516 2517 2518
	struct i2c_client *temp_client;
	int i, err = 0;
	int adap_id = i2c_adapter_id(adapter);

2519 2520
	address_list = driver->address_list;
	if (!driver->detect || !address_list)
2521 2522
		return 0;

2523 2524 2525 2526 2527 2528 2529 2530 2531 2532
	/* Warn that the adapter lost class based instantiation */
	if (adapter->class == I2C_CLASS_DEPRECATED) {
		dev_dbg(&adapter->dev,
			"This adapter dropped support for I2C classes and "
			"won't auto-detect %s devices anymore. If you need it, check "
			"'Documentation/i2c/instantiating-devices' for alternatives.\n",
			driver->driver.name);
		return 0;
	}

J
Jean Delvare 已提交
2533 2534 2535 2536
	/* Stop here if the classes do not match */
	if (!(adapter->class & driver->class))
		return 0;

2537 2538 2539 2540 2541 2542
	/* Set up a temporary client to help detect callback */
	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
	if (!temp_client)
		return -ENOMEM;
	temp_client->adapter = adapter;

2543
	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2544
		dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
2545 2546
			"addr 0x%02x\n", adap_id, address_list[i]);
		temp_client->addr = address_list[i];
J
Jean Delvare 已提交
2547
		err = i2c_detect_address(temp_client, driver);
J
Jean Delvare 已提交
2548 2549
		if (unlikely(err))
			break;
2550 2551 2552 2553 2554 2555
	}

	kfree(temp_client);
	return err;
}

2556 2557 2558 2559 2560 2561 2562
int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
{
	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
			      I2C_SMBUS_QUICK, NULL) >= 0;
}
EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);

J
Jean Delvare 已提交
2563 2564 2565
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
		      struct i2c_board_info *info,
2566 2567
		      unsigned short const *addr_list,
		      int (*probe)(struct i2c_adapter *, unsigned short addr))
J
Jean Delvare 已提交
2568 2569 2570
{
	int i;

2571
	if (!probe)
2572
		probe = i2c_default_probe;
J
Jean Delvare 已提交
2573 2574 2575

	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
		/* Check address validity */
2576
		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
J
Jean Delvare 已提交
2577 2578 2579 2580 2581
			dev_warn(&adap->dev, "Invalid 7-bit address "
				 "0x%02x\n", addr_list[i]);
			continue;
		}

2582
		/* Check address availability (7 bit, no need to encode flags) */
2583
		if (i2c_check_addr_busy(adap, addr_list[i])) {
J
Jean Delvare 已提交
2584 2585 2586 2587 2588
			dev_dbg(&adap->dev, "Address 0x%02x already in "
				"use, not probing\n", addr_list[i]);
			continue;
		}

2589
		/* Test address responsiveness */
2590
		if (probe(adap, addr_list[i]))
2591
			break;
J
Jean Delvare 已提交
2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603
	}

	if (addr_list[i] == I2C_CLIENT_END) {
		dev_dbg(&adap->dev, "Probing failed, no device found\n");
		return NULL;
	}

	info->addr = addr_list[i];
	return i2c_new_device(adap, info);
}
EXPORT_SYMBOL_GPL(i2c_new_probed_device);

2604
struct i2c_adapter *i2c_get_adapter(int nr)
L
Linus Torvalds 已提交
2605 2606
{
	struct i2c_adapter *adapter;
D
David Brownell 已提交
2607

J
Jean Delvare 已提交
2608
	mutex_lock(&core_lock);
2609
	adapter = idr_find(&i2c_adapter_idr, nr);
2610 2611 2612 2613 2614 2615
	if (!adapter)
		goto exit;

	if (try_module_get(adapter->owner))
		get_device(&adapter->dev);
	else
2616 2617
		adapter = NULL;

2618
 exit:
J
Jean Delvare 已提交
2619
	mutex_unlock(&core_lock);
2620
	return adapter;
L
Linus Torvalds 已提交
2621
}
D
David Brownell 已提交
2622
EXPORT_SYMBOL(i2c_get_adapter);
L
Linus Torvalds 已提交
2623 2624 2625

void i2c_put_adapter(struct i2c_adapter *adap)
{
2626 2627 2628 2629 2630
	if (!adap)
		return;

	put_device(&adap->dev);
	module_put(adap->owner);
L
Linus Torvalds 已提交
2631
}
D
David Brownell 已提交
2632
EXPORT_SYMBOL(i2c_put_adapter);
L
Linus Torvalds 已提交
2633 2634 2635

/* The SMBus parts */

D
David Brownell 已提交
2636
#define POLY    (0x1070U << 3)
Z
Zhenwen Xu 已提交
2637
static u8 crc8(u16 data)
L
Linus Torvalds 已提交
2638 2639
{
	int i;
D
David Brownell 已提交
2640

2641
	for (i = 0; i < 8; i++) {
D
David Brownell 已提交
2642
		if (data & 0x8000)
L
Linus Torvalds 已提交
2643 2644 2645 2646 2647 2648
			data = data ^ POLY;
		data = data << 1;
	}
	return (u8)(data >> 8);
}

2649 2650
/* Incremental CRC8 over count bytes in the array pointed to by p */
static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
L
Linus Torvalds 已提交
2651 2652 2653
{
	int i;

2654
	for (i = 0; i < count; i++)
2655
		crc = crc8((crc ^ p[i]) << 8);
L
Linus Torvalds 已提交
2656 2657 2658
	return crc;
}

2659 2660
/* Assume a 7-bit address, which is reasonable for SMBus */
static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
L
Linus Torvalds 已提交
2661
{
2662
	/* The address will be sent first */
2663
	u8 addr = i2c_8bit_addr_from_msg(msg);
2664 2665 2666 2667
	pec = i2c_smbus_pec(pec, &addr, 1);

	/* The data buffer follows */
	return i2c_smbus_pec(pec, msg->buf, msg->len);
L
Linus Torvalds 已提交
2668 2669
}

2670 2671
/* Used for write only transactions */
static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
L
Linus Torvalds 已提交
2672
{
2673 2674
	msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
	msg->len++;
L
Linus Torvalds 已提交
2675 2676
}

2677 2678 2679 2680 2681 2682
/* Return <0 on CRC error
   If there was a write before this read (most cases) we need to take the
   partial CRC from the write part into account.
   Note that this function does modify the message (we need to decrease the
   message length to hide the CRC byte from the caller). */
static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
L
Linus Torvalds 已提交
2683
{
2684 2685
	u8 rpec = msg->buf[--msg->len];
	cpec = i2c_smbus_msg_pec(cpec, msg);
L
Linus Torvalds 已提交
2686 2687 2688 2689

	if (rpec != cpec) {
		pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
			rpec, cpec);
D
David Brownell 已提交
2690
		return -EBADMSG;
L
Linus Torvalds 已提交
2691
	}
D
David Brownell 已提交
2692
	return 0;
L
Linus Torvalds 已提交
2693 2694
}

2695 2696 2697 2698 2699 2700 2701
/**
 * i2c_smbus_read_byte - SMBus "receive byte" protocol
 * @client: Handle to slave device
 *
 * This executes the SMBus "receive byte" protocol, returning negative errno
 * else the byte received from the device.
 */
2702
s32 i2c_smbus_read_byte(const struct i2c_client *client)
L
Linus Torvalds 已提交
2703 2704
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2705 2706 2707 2708 2709 2710
	int status;

	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, 0,
				I2C_SMBUS_BYTE, &data);
	return (status < 0) ? status : data.byte;
L
Linus Torvalds 已提交
2711
}
D
David Brownell 已提交
2712
EXPORT_SYMBOL(i2c_smbus_read_byte);
L
Linus Torvalds 已提交
2713

2714 2715 2716 2717 2718 2719 2720 2721
/**
 * i2c_smbus_write_byte - SMBus "send byte" protocol
 * @client: Handle to slave device
 * @value: Byte to be sent
 *
 * This executes the SMBus "send byte" protocol, returning negative errno
 * else zero on success.
 */
2722
s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
L
Linus Torvalds 已提交
2723
{
2724
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2725
	                      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
L
Linus Torvalds 已提交
2726
}
D
David Brownell 已提交
2727
EXPORT_SYMBOL(i2c_smbus_write_byte);
L
Linus Torvalds 已提交
2728

2729 2730 2731 2732 2733 2734 2735 2736
/**
 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 *
 * This executes the SMBus "read byte" protocol, returning negative errno
 * else a data byte received from the device.
 */
2737
s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
2738 2739
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2740 2741 2742 2743 2744 2745
	int status;

	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_BYTE_DATA, &data);
	return (status < 0) ? status : data.byte;
L
Linus Torvalds 已提交
2746
}
D
David Brownell 已提交
2747
EXPORT_SYMBOL(i2c_smbus_read_byte_data);
L
Linus Torvalds 已提交
2748

2749 2750 2751 2752 2753 2754 2755 2756 2757
/**
 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 * @value: Byte being written
 *
 * This executes the SMBus "write byte" protocol, returning negative errno
 * else zero on success.
 */
2758 2759
s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
			      u8 value)
L
Linus Torvalds 已提交
2760 2761 2762
{
	union i2c_smbus_data data;
	data.byte = value;
2763 2764 2765
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
			      I2C_SMBUS_WRITE, command,
			      I2C_SMBUS_BYTE_DATA, &data);
L
Linus Torvalds 已提交
2766
}
D
David Brownell 已提交
2767
EXPORT_SYMBOL(i2c_smbus_write_byte_data);
L
Linus Torvalds 已提交
2768

2769 2770 2771 2772 2773 2774 2775 2776
/**
 * i2c_smbus_read_word_data - SMBus "read word" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 *
 * This executes the SMBus "read word" protocol, returning negative errno
 * else a 16-bit unsigned "word" received from the device.
 */
2777
s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
L
Linus Torvalds 已提交
2778 2779
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2780 2781 2782 2783 2784 2785
	int status;

	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_WORD_DATA, &data);
	return (status < 0) ? status : data.word;
L
Linus Torvalds 已提交
2786
}
D
David Brownell 已提交
2787
EXPORT_SYMBOL(i2c_smbus_read_word_data);
L
Linus Torvalds 已提交
2788

2789 2790 2791 2792 2793 2794 2795 2796 2797
/**
 * i2c_smbus_write_word_data - SMBus "write word" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 * @value: 16-bit "word" being written
 *
 * This executes the SMBus "write word" protocol, returning negative errno
 * else zero on success.
 */
2798 2799
s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
			      u16 value)
L
Linus Torvalds 已提交
2800 2801 2802
{
	union i2c_smbus_data data;
	data.word = value;
2803 2804 2805
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
			      I2C_SMBUS_WRITE, command,
			      I2C_SMBUS_WORD_DATA, &data);
L
Linus Torvalds 已提交
2806
}
D
David Brownell 已提交
2807
EXPORT_SYMBOL(i2c_smbus_write_word_data);
L
Linus Torvalds 已提交
2808

D
David Brownell 已提交
2809
/**
2810
 * i2c_smbus_read_block_data - SMBus "block read" protocol
D
David Brownell 已提交
2811
 * @client: Handle to slave device
2812
 * @command: Byte interpreted by slave
D
David Brownell 已提交
2813 2814 2815
 * @values: Byte array into which data will be read; big enough to hold
 *	the data returned by the slave.  SMBus allows at most 32 bytes.
 *
2816 2817
 * This executes the SMBus "block read" protocol, returning negative errno
 * else the number of data bytes in the slave's response.
D
David Brownell 已提交
2818 2819 2820 2821 2822 2823
 *
 * Note that using this function requires that the client's adapter support
 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality.  Not all adapter drivers
 * support this; its emulation through I2C messaging relies on a specific
 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
 */
2824
s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2825 2826 2827
			      u8 *values)
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2828
	int status;
2829

D
David Brownell 已提交
2830 2831 2832 2833 2834
	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_BLOCK_DATA, &data);
	if (status)
		return status;
2835 2836 2837 2838 2839 2840

	memcpy(values, &data.block[1], data.block[0]);
	return data.block[0];
}
EXPORT_SYMBOL(i2c_smbus_read_block_data);

2841 2842 2843 2844 2845 2846 2847 2848 2849 2850
/**
 * i2c_smbus_write_block_data - SMBus "block write" protocol
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 * @length: Size of data block; SMBus allows at most 32 bytes
 * @values: Byte array which will be written.
 *
 * This executes the SMBus "block write" protocol, returning negative errno
 * else zero on success.
 */
2851
s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2852
			       u8 length, const u8 *values)
L
Linus Torvalds 已提交
2853 2854
{
	union i2c_smbus_data data;
2855

L
Linus Torvalds 已提交
2856 2857 2858
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
2859
	memcpy(&data.block[1], values, length);
2860 2861 2862
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
			      I2C_SMBUS_WRITE, command,
			      I2C_SMBUS_BLOCK_DATA, &data);
L
Linus Torvalds 已提交
2863
}
D
David Brownell 已提交
2864
EXPORT_SYMBOL(i2c_smbus_write_block_data);
L
Linus Torvalds 已提交
2865 2866

/* Returns the number of read bytes */
2867
s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2868
				  u8 length, u8 *values)
L
Linus Torvalds 已提交
2869 2870
{
	union i2c_smbus_data data;
D
David Brownell 已提交
2871
	int status;
2872

2873 2874 2875
	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
D
David Brownell 已提交
2876 2877 2878 2879 2880
	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
				I2C_SMBUS_READ, command,
				I2C_SMBUS_I2C_BLOCK_DATA, &data);
	if (status < 0)
		return status;
2881 2882 2883

	memcpy(values, &data.block[1], data.block[0]);
	return data.block[0];
L
Linus Torvalds 已提交
2884
}
D
David Brownell 已提交
2885
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
L
Linus Torvalds 已提交
2886

2887
s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2888
				   u8 length, const u8 *values)
2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899
{
	union i2c_smbus_data data;

	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;
	data.block[0] = length;
	memcpy(data.block + 1, values, length);
	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
			      I2C_SMBUS_WRITE, command,
			      I2C_SMBUS_I2C_BLOCK_DATA, &data);
}
D
David Brownell 已提交
2900
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2901

D
David Brownell 已提交
2902
/* Simulate a SMBus command using the i2c protocol
L
Linus Torvalds 已提交
2903
   No checking of parameters is done!  */
2904 2905 2906 2907
static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
				   unsigned short flags,
				   char read_write, u8 command, int size,
				   union i2c_smbus_data *data)
L
Linus Torvalds 已提交
2908 2909 2910 2911 2912
{
	/* So we need to generate a series of msgs. In the case of writing, we
	  need to use only one message; when reading, we need two. We initialize
	  most things with sane defaults, to keep the code below somewhat
	  simpler. */
2913 2914
	unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
	unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2915
	int num = read_write == I2C_SMBUS_READ ? 2 : 1;
L
Linus Torvalds 已提交
2916
	int i;
2917
	u8 partial_pec = 0;
D
David Brownell 已提交
2918
	int status;
2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931
	struct i2c_msg msg[2] = {
		{
			.addr = addr,
			.flags = flags,
			.len = 1,
			.buf = msgbuf0,
		}, {
			.addr = addr,
			.flags = flags | I2C_M_RD,
			.len = 0,
			.buf = msgbuf1,
		},
	};
L
Linus Torvalds 已提交
2932 2933

	msgbuf0[0] = command;
2934
	switch (size) {
L
Linus Torvalds 已提交
2935 2936 2937
	case I2C_SMBUS_QUICK:
		msg[0].len = 0;
		/* Special case: The read/write field is used as data */
R
Roel Kluin 已提交
2938 2939
		msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
					I2C_M_RD : 0);
L
Linus Torvalds 已提交
2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960
		num = 1;
		break;
	case I2C_SMBUS_BYTE:
		if (read_write == I2C_SMBUS_READ) {
			/* Special case: only a read! */
			msg[0].flags = I2C_M_RD | flags;
			num = 1;
		}
		break;
	case I2C_SMBUS_BYTE_DATA:
		if (read_write == I2C_SMBUS_READ)
			msg[1].len = 1;
		else {
			msg[0].len = 2;
			msgbuf0[1] = data->byte;
		}
		break;
	case I2C_SMBUS_WORD_DATA:
		if (read_write == I2C_SMBUS_READ)
			msg[1].len = 2;
		else {
2961
			msg[0].len = 3;
L
Linus Torvalds 已提交
2962
			msgbuf0[1] = data->word & 0xff;
2963
			msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
2964 2965 2966 2967 2968 2969 2970 2971
		}
		break;
	case I2C_SMBUS_PROC_CALL:
		num = 2; /* Special case */
		read_write = I2C_SMBUS_READ;
		msg[0].len = 3;
		msg[1].len = 2;
		msgbuf0[1] = data->word & 0xff;
2972
		msgbuf0[2] = data->word >> 8;
L
Linus Torvalds 已提交
2973 2974 2975
		break;
	case I2C_SMBUS_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
2976 2977 2978
			msg[1].flags |= I2C_M_RECV_LEN;
			msg[1].len = 1; /* block length will be added by
					   the underlying bus driver */
L
Linus Torvalds 已提交
2979 2980 2981
		} else {
			msg[0].len = data->block[0] + 2;
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
D
David Brownell 已提交
2982 2983 2984 2985
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
2986
			}
2987
			for (i = 1; i < msg[0].len; i++)
L
Linus Torvalds 已提交
2988 2989 2990 2991
				msgbuf0[i] = data->block[i-1];
		}
		break;
	case I2C_SMBUS_BLOCK_PROC_CALL:
2992 2993 2994
		num = 2; /* Another special case */
		read_write = I2C_SMBUS_READ;
		if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
D
David Brownell 已提交
2995 2996
			dev_err(&adapter->dev,
				"Invalid block write size %d\n",
2997
				data->block[0]);
D
David Brownell 已提交
2998
			return -EINVAL;
2999 3000 3001 3002 3003 3004 3005 3006
		}
		msg[0].len = data->block[0] + 2;
		for (i = 1; i < msg[0].len; i++)
			msgbuf0[i] = data->block[i-1];
		msg[1].flags |= I2C_M_RECV_LEN;
		msg[1].len = 1; /* block length will be added by
				   the underlying bus driver */
		break;
L
Linus Torvalds 已提交
3007 3008
	case I2C_SMBUS_I2C_BLOCK_DATA:
		if (read_write == I2C_SMBUS_READ) {
3009
			msg[1].len = data->block[0];
L
Linus Torvalds 已提交
3010 3011
		} else {
			msg[0].len = data->block[0] + 1;
3012
			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
D
David Brownell 已提交
3013 3014 3015 3016
				dev_err(&adapter->dev,
					"Invalid block write size %d\n",
					data->block[0]);
				return -EINVAL;
L
Linus Torvalds 已提交
3017 3018 3019 3020 3021 3022
			}
			for (i = 1; i <= data->block[0]; i++)
				msgbuf0[i] = data->block[i];
		}
		break;
	default:
D
David Brownell 已提交
3023 3024
		dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
3025 3026
	}

3027 3028 3029 3030 3031
	i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
				      && size != I2C_SMBUS_I2C_BLOCK_DATA);
	if (i) {
		/* Compute PEC if first message is a write */
		if (!(msg[0].flags & I2C_M_RD)) {
D
David Brownell 已提交
3032
			if (num == 1) /* Write only */
3033 3034 3035 3036 3037 3038
				i2c_smbus_add_pec(&msg[0]);
			else /* Write followed by read */
				partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
		}
		/* Ask for PEC if last message is a read */
		if (msg[num-1].flags & I2C_M_RD)
D
David Brownell 已提交
3039
			msg[num-1].len++;
3040 3041
	}

D
David Brownell 已提交
3042 3043 3044
	status = i2c_transfer(adapter, msg, num);
	if (status < 0)
		return status;
L
Linus Torvalds 已提交
3045

3046 3047
	/* Check PEC if last message is a read */
	if (i && (msg[num-1].flags & I2C_M_RD)) {
D
David Brownell 已提交
3048 3049 3050
		status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
		if (status < 0)
			return status;
3051 3052
	}

L
Linus Torvalds 已提交
3053
	if (read_write == I2C_SMBUS_READ)
3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073
		switch (size) {
		case I2C_SMBUS_BYTE:
			data->byte = msgbuf0[0];
			break;
		case I2C_SMBUS_BYTE_DATA:
			data->byte = msgbuf1[0];
			break;
		case I2C_SMBUS_WORD_DATA:
		case I2C_SMBUS_PROC_CALL:
			data->word = msgbuf1[0] | (msgbuf1[1] << 8);
			break;
		case I2C_SMBUS_I2C_BLOCK_DATA:
			for (i = 0; i < data->block[0]; i++)
				data->block[i+1] = msgbuf1[i];
			break;
		case I2C_SMBUS_BLOCK_DATA:
		case I2C_SMBUS_BLOCK_PROC_CALL:
			for (i = 0; i < msgbuf1[0] + 1; i++)
				data->block[i] = msgbuf1[i];
			break;
L
Linus Torvalds 已提交
3074 3075 3076 3077
		}
	return 0;
}

3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090
/**
 * i2c_smbus_xfer - execute SMBus protocol operations
 * @adapter: Handle to I2C bus
 * @addr: Address of SMBus slave on that bus
 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
 * @command: Byte interpreted by slave, for protocols which use such bytes
 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
 * @data: Data to be read or written
 *
 * This executes an SMBus protocol operation, and returns a negative
 * errno code else zero on success.
 */
Z
Zhenwen Xu 已提交
3091
s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
3092
		   char read_write, u8 command, int protocol,
Z
Zhenwen Xu 已提交
3093
		   union i2c_smbus_data *data)
L
Linus Torvalds 已提交
3094
{
3095 3096
	unsigned long orig_jiffies;
	int try;
L
Linus Torvalds 已提交
3097 3098
	s32 res;

3099 3100 3101 3102 3103 3104 3105 3106
	/* If enabled, the following two tracepoints are conditional on
	 * read_write and protocol.
	 */
	trace_smbus_write(adapter, addr, flags, read_write,
			  command, protocol, data);
	trace_smbus_read(adapter, addr, flags, read_write,
			 command, protocol);

L
Laurent Pinchart 已提交
3107
	flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
L
Linus Torvalds 已提交
3108 3109

	if (adapter->algo->smbus_xfer) {
3110
		i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123

		/* Retry automatically on arbitration loss */
		orig_jiffies = jiffies;
		for (res = 0, try = 0; try <= adapter->retries; try++) {
			res = adapter->algo->smbus_xfer(adapter, addr, flags,
							read_write, command,
							protocol, data);
			if (res != -EAGAIN)
				break;
			if (time_after(jiffies,
				       orig_jiffies + adapter->timeout))
				break;
		}
3124
		i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
3125

3126
		if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
3127
			goto trace;
3128 3129 3130 3131 3132 3133
		/*
		 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
		 * implement native support for the SMBus operation.
		 */
	}

3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144
	res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
				      command, protocol, data);

trace:
	/* If enabled, the reply tracepoint is conditional on read_write. */
	trace_smbus_reply(adapter, addr, flags, read_write,
			  command, protocol, data);
	trace_smbus_result(adapter, addr, flags, read_write,
			   command, protocol, res);

	return res;
L
Linus Torvalds 已提交
3145 3146 3147
}
EXPORT_SYMBOL(i2c_smbus_xfer);

3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204
/**
 * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
 * @client: Handle to slave device
 * @command: Byte interpreted by slave
 * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes
 * @values: Byte array into which data will be read; big enough to hold
 *	the data returned by the slave.  SMBus allows at most
 *	I2C_SMBUS_BLOCK_MAX bytes.
 *
 * This executes the SMBus "block read" protocol if supported by the adapter.
 * If block read is not supported, it emulates it using either word or byte
 * read protocols depending on availability.
 *
 * The addresses of the I2C slave device that are accessed with this function
 * must be mapped to a linear region, so that a block read will have the same
 * effect as a byte read. Before using this function you must double-check
 * if the I2C slave does support exchanging a block transfer with a byte
 * transfer.
 */
s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
					      u8 command, u8 length, u8 *values)
{
	u8 i = 0;
	int status;

	if (length > I2C_SMBUS_BLOCK_MAX)
		length = I2C_SMBUS_BLOCK_MAX;

	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
		return i2c_smbus_read_i2c_block_data(client, command, length, values);

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA))
		return -EOPNOTSUPP;

	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) {
		while ((i + 2) <= length) {
			status = i2c_smbus_read_word_data(client, command + i);
			if (status < 0)
				return status;
			values[i] = status & 0xff;
			values[i + 1] = status >> 8;
			i += 2;
		}
	}

	while (i < length) {
		status = i2c_smbus_read_byte_data(client, command + i);
		if (status < 0)
			return status;
		values[i] = status;
		i++;
	}

	return i;
}
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated);

3205
#if IS_ENABLED(CONFIG_I2C_SLAVE)
W
Wolfram Sang 已提交
3206 3207 3208 3209
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{
	int ret;

3210 3211
	if (!client || !slave_cb) {
		WARN(1, "insufficent data\n");
W
Wolfram Sang 已提交
3212
		return -EINVAL;
3213
	}
W
Wolfram Sang 已提交
3214

3215 3216 3217 3218
	if (!(client->flags & I2C_CLIENT_SLAVE))
		dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n",
			 __func__);

W
Wolfram Sang 已提交
3219 3220
	if (!(client->flags & I2C_CLIENT_TEN)) {
		/* Enforce stricter address checking */
3221
		ret = i2c_check_7bit_addr_validity_strict(client->addr);
3222 3223
		if (ret) {
			dev_err(&client->dev, "%s: invalid address\n", __func__);
W
Wolfram Sang 已提交
3224
			return ret;
3225
		}
W
Wolfram Sang 已提交
3226 3227
	}

3228 3229
	if (!client->adapter->algo->reg_slave) {
		dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
W
Wolfram Sang 已提交
3230
		return -EOPNOTSUPP;
3231
	}
W
Wolfram Sang 已提交
3232 3233 3234 3235 3236 3237 3238

	client->slave_cb = slave_cb;

	i2c_lock_adapter(client->adapter);
	ret = client->adapter->algo->reg_slave(client);
	i2c_unlock_adapter(client->adapter);

3239
	if (ret) {
W
Wolfram Sang 已提交
3240
		client->slave_cb = NULL;
3241 3242
		dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
	}
W
Wolfram Sang 已提交
3243 3244 3245 3246 3247 3248 3249 3250 3251

	return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_register);

int i2c_slave_unregister(struct i2c_client *client)
{
	int ret;

3252 3253
	if (!client->adapter->algo->unreg_slave) {
		dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
W
Wolfram Sang 已提交
3254
		return -EOPNOTSUPP;
3255
	}
W
Wolfram Sang 已提交
3256 3257 3258 3259 3260 3261 3262

	i2c_lock_adapter(client->adapter);
	ret = client->adapter->algo->unreg_slave(client);
	i2c_unlock_adapter(client->adapter);

	if (ret == 0)
		client->slave_cb = NULL;
3263 3264
	else
		dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
W
Wolfram Sang 已提交
3265 3266 3267 3268

	return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_unregister);
3269
#endif
W
Wolfram Sang 已提交
3270

L
Linus Torvalds 已提交
3271 3272 3273
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");