1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Linux I2C core
   4 *
   5 * Copyright (C) 1995-99 Simon G. Vogl
   6 *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
   7 *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   8 *   Michael Lawnick <michael.lawnick.ext@nsn.com>
   9 *
  10 * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
  11 */
  12
  13#define pr_fmt(fmt) "i2c-core: " fmt
  14
  15#include <dt-bindings/i2c/i2c.h>
  16#include <linux/acpi.h>
  17#include <linux/clk/clk-conf.h>
  18#include <linux/completion.h>
  19#include <linux/delay.h>
  20#include <linux/err.h>
  21#include <linux/errno.h>
  22#include <linux/gpio/consumer.h>
  23#include <linux/i2c.h>
  24#include <linux/i2c-smbus.h>
  25#include <linux/idr.h>
  26#include <linux/init.h>
  27#include <linux/irqflags.h>
  28#include <linux/jump_label.h>
  29#include <linux/kernel.h>
  30#include <linux/module.h>
  31#include <linux/mutex.h>
  32#include <linux/of_device.h>
  33#include <linux/of.h>
  34#include <linux/of_irq.h>
  35#include <linux/pinctrl/consumer.h>
  36#include <linux/pm_domain.h>
  37#include <linux/pm_runtime.h>
  38#include <linux/pm_wakeirq.h>
  39#include <linux/property.h>
  40#include <linux/rwsem.h>
  41#include <linux/slab.h>
  42
  43#include "i2c-core.h"
  44
  45#define CREATE_TRACE_POINTS
  46#include <trace/events/i2c.h>
  47
  48#define I2C_ADDR_OFFSET_TEN_BIT	0xa000
  49#define I2C_ADDR_OFFSET_SLAVE	0x1000
  50
  51#define I2C_ADDR_7BITS_MAX	0x77
  52#define I2C_ADDR_7BITS_COUNT	(I2C_ADDR_7BITS_MAX + 1)
  53
  54#define I2C_ADDR_DEVICE_ID	0x7c
  55
  56/*
  57 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  58 * deletion of detected devices are serialized
  59 */
  60static DEFINE_MUTEX(core_lock);
  61static DEFINE_IDR(i2c_adapter_idr);
  62
  63static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  64
  65static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
  66static bool is_registered;
  67
  68int i2c_transfer_trace_reg(void)
  69{
  70	static_branch_inc(&i2c_trace_msg_key);
  71	return 0;
  72}
  73
  74void i2c_transfer_trace_unreg(void)
  75{
  76	static_branch_dec(&i2c_trace_msg_key);
  77}
  78
  79const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  80						const struct i2c_client *client)
  81{
  82	if (!(id && client))
  83		return NULL;
  84
  85	while (id->name[0]) {
  86		if (strcmp(client->name, id->name) == 0)
  87			return id;
  88		id++;
  89	}
  90	return NULL;
  91}
  92EXPORT_SYMBOL_GPL(i2c_match_id);
  93
  94static int i2c_device_match(struct device *dev, struct device_driver *drv)
  95{
  96	struct i2c_client	*client = i2c_verify_client(dev);
  97	struct i2c_driver	*driver;
  98
  99
 100	/* Attempt an OF style match */
 101	if (i2c_of_match_device(drv->of_match_table, client))
 102		return 1;
 103
 104	/* Then ACPI style match */
 105	if (acpi_driver_match_device(dev, drv))
 106		return 1;
 107
 108	driver = to_i2c_driver(drv);
 109
 110	/* Finally an I2C match */
 111	if (i2c_match_id(driver->id_table, client))
 112		return 1;
 113
 114	return 0;
 115}
 116
 117static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 118{
 119	struct i2c_client *client = to_i2c_client(dev);
 120	int rc;
 121
 122	rc = of_device_uevent_modalias(dev, env);
 123	if (rc != -ENODEV)
 124		return rc;
 125
 126	rc = acpi_device_uevent_modalias(dev, env);
 127	if (rc != -ENODEV)
 128		return rc;
 129
 130	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 131}
 132
 133/* i2c bus recovery routines */
 134static int get_scl_gpio_value(struct i2c_adapter *adap)
 135{
 136	return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
 137}
 138
 139static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 140{
 141	gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
 142}
 143
 144static int get_sda_gpio_value(struct i2c_adapter *adap)
 145{
 146	return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
 147}
 148
 149static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
 150{
 151	gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
 152}
 153
 154static int i2c_generic_bus_free(struct i2c_adapter *adap)
 155{
 156	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 157	int ret = -EOPNOTSUPP;
 158
 159	if (bri->get_bus_free)
 160		ret = bri->get_bus_free(adap);
 161	else if (bri->get_sda)
 162		ret = bri->get_sda(adap);
 163
 164	if (ret < 0)
 165		return ret;
 166
 167	return ret ? 0 : -EBUSY;
 168}
 169
 170/*
 171 * We are generating clock pulses. ndelay() determines durating of clk pulses.
 172 * We will generate clock with rate 100 KHz and so duration of both clock levels
 173 * is: delay in ns = (10^6 / 100) / 2
 174 */
 175#define RECOVERY_NDELAY		5000
 176#define RECOVERY_CLK_CNT	9
 177
 178int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 179{
 180	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 181	int i = 0, scl = 1, ret = 0;
 182
 183	if (bri->prepare_recovery)
 184		bri->prepare_recovery(adap);
 185	if (bri->pinctrl)
 186		pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
 187
 188	/*
 189	 * If we can set SDA, we will always create a STOP to ensure additional
 190	 * pulses will do no harm. This is achieved by letting SDA follow SCL
 191	 * half a cycle later. Check the 'incomplete_write_byte' fault injector
 192	 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
 193	 * here for simplicity.
 194	 */
 195	bri->set_scl(adap, scl);
 196	ndelay(RECOVERY_NDELAY);
 197	if (bri->set_sda)
 198		bri->set_sda(adap, scl);
 199	ndelay(RECOVERY_NDELAY / 2);
 200
 201	/*
 202	 * By this time SCL is high, as we need to give 9 falling-rising edges
 203	 */
 204	while (i++ < RECOVERY_CLK_CNT * 2) {
 205		if (scl) {
 206			/* SCL shouldn't be low here */
 207			if (!bri->get_scl(adap)) {
 208				dev_err(&adap->dev,
 209					"SCL is stuck low, exit recovery\n");
 210				ret = -EBUSY;
 211				break;
 212			}
 213		}
 214
 215		scl = !scl;
 216		bri->set_scl(adap, scl);
 217		/* Creating STOP again, see above */
 218		if (scl)  {
 219			/* Honour minimum tsu:sto */
 220			ndelay(RECOVERY_NDELAY);
 221		} else {
 222			/* Honour minimum tf and thd:dat */
 223			ndelay(RECOVERY_NDELAY / 2);
 224		}
 225		if (bri->set_sda)
 226			bri->set_sda(adap, scl);
 227		ndelay(RECOVERY_NDELAY / 2);
 228
 229		if (scl) {
 230			ret = i2c_generic_bus_free(adap);
 231			if (ret == 0)
 232				break;
 233		}
 234	}
 235
 236	/* If we can't check bus status, assume recovery worked */
 237	if (ret == -EOPNOTSUPP)
 238		ret = 0;
 239
 240	if (bri->unprepare_recovery)
 241		bri->unprepare_recovery(adap);
 242	if (bri->pinctrl)
 243		pinctrl_select_state(bri->pinctrl, bri->pins_default);
 244
 245	return ret;
 246}
 247EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 248
 249int i2c_recover_bus(struct i2c_adapter *adap)
 250{
 251	if (!adap->bus_recovery_info)
 252		return -EOPNOTSUPP;
 253
 254	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 255	return adap->bus_recovery_info->recover_bus(adap);
 256}
 257EXPORT_SYMBOL_GPL(i2c_recover_bus);
 258
 259static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
 260{
 261	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 262	struct device *dev = &adap->dev;
 263	struct pinctrl *p = bri->pinctrl;
 264
 265	/*
 266	 * we can't change states without pinctrl, so remove the states if
 267	 * populated
 268	 */
 269	if (!p) {
 270		bri->pins_default = NULL;
 271		bri->pins_gpio = NULL;
 272		return;
 273	}
 274
 275	if (!bri->pins_default) {
 276		bri->pins_default = pinctrl_lookup_state(p,
 277							 PINCTRL_STATE_DEFAULT);
 278		if (IS_ERR(bri->pins_default)) {
 279			dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
 280			bri->pins_default = NULL;
 281		}
 282	}
 283	if (!bri->pins_gpio) {
 284		bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
 285		if (IS_ERR(bri->pins_gpio))
 286			bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
 287
 288		if (IS_ERR(bri->pins_gpio)) {
 289			dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
 290			bri->pins_gpio = NULL;
 291		}
 292	}
 293
 294	/* for pinctrl state changes, we need all the information */
 295	if (bri->pins_default && bri->pins_gpio) {
 296		dev_info(dev, "using pinctrl states for GPIO recovery");
 297	} else {
 298		bri->pinctrl = NULL;
 299		bri->pins_default = NULL;
 300		bri->pins_gpio = NULL;
 301	}
 302}
 303
 304static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
 305{
 306	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 307	struct device *dev = &adap->dev;
 308	struct gpio_desc *gpiod;
 309	int ret = 0;
 310
 311	/*
 312	 * don't touch the recovery information if the driver is not using
 313	 * generic SCL recovery
 314	 */
 315	if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
 316		return 0;
 317
 318	/*
 319	 * pins might be taken as GPIO, so we should inform pinctrl about
 320	 * this and move the state to GPIO
 321	 */
 322	if (bri->pinctrl)
 323		pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
 324
 325	/*
 326	 * if there is incomplete or no recovery information, see if generic
 327	 * GPIO recovery is available
 328	 */
 329	if (!bri->scl_gpiod) {
 330		gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
 331		if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
 332			ret  = -EPROBE_DEFER;
 333			goto cleanup_pinctrl_state;
 334		}
 335		if (!IS_ERR(gpiod)) {
 336			bri->scl_gpiod = gpiod;
 337			bri->recover_bus = i2c_generic_scl_recovery;
 338			dev_info(dev, "using generic GPIOs for recovery\n");
 339		}
 340	}
 341
 342	/* SDA GPIOD line is optional, so we care about DEFER only */
 343	if (!bri->sda_gpiod) {
 344		/*
 345		 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
 346		 * have no effect.
 347		 */
 348		gpiod_direction_output(bri->scl_gpiod, 0);
 349		udelay(10);
 350		gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
 351
 352		/* Wait a bit in case of a SDA glitch, and then release SCL. */
 353		udelay(10);
 354		gpiod_direction_output(bri->scl_gpiod, 1);
 355
 356		if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
 357			ret = -EPROBE_DEFER;
 358			goto cleanup_pinctrl_state;
 359		}
 360		if (!IS_ERR(gpiod))
 361			bri->sda_gpiod = gpiod;
 362	}
 363
 364cleanup_pinctrl_state:
 365	/* change the state of the pins back to their default state */
 366	if (bri->pinctrl)
 367		pinctrl_select_state(bri->pinctrl, bri->pins_default);
 368
 369	return ret;
 370}
 371
 372static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
 373{
 374	i2c_gpio_init_pinctrl_recovery(adap);
 375	return i2c_gpio_init_generic_recovery(adap);
 376}
 377
 378static int i2c_init_recovery(struct i2c_adapter *adap)
 379{
 380	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 381	char *err_str;
 382
 383	if (!bri)
 384		return 0;
 385
 386	if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
 387		return -EPROBE_DEFER;
 388
 389	if (!bri->recover_bus) {
 390		err_str = "no recover_bus() found";
 391		goto err;
 392	}
 393
 394	if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 395		bri->get_scl = get_scl_gpio_value;
 396		bri->set_scl = set_scl_gpio_value;
 397		if (bri->sda_gpiod) {
 398			bri->get_sda = get_sda_gpio_value;
 399			/* FIXME: add proper flag instead of '0' once available */
 400			if (gpiod_get_direction(bri->sda_gpiod) == 0)
 401				bri->set_sda = set_sda_gpio_value;
 402		}
 403	} else if (bri->recover_bus == i2c_generic_scl_recovery) {
 
 
 
 404		/* Generic SCL recovery */
 405		if (!bri->set_scl || !bri->get_scl) {
 406			err_str = "no {get|set}_scl() found";
 407			goto err;
 408		}
 409		if (!bri->set_sda && !bri->get_sda) {
 410			err_str = "either get_sda() or set_sda() needed";
 411			goto err;
 412		}
 413	}
 414
 415	return 0;
 416 err:
 417	dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 418	adap->bus_recovery_info = NULL;
 419
 420	return -EINVAL;
 421}
 422
 423static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 424{
 425	struct i2c_adapter *adap = client->adapter;
 426	unsigned int irq;
 427
 428	if (!adap->host_notify_domain)
 429		return -ENXIO;
 430
 431	if (client->flags & I2C_CLIENT_TEN)
 432		return -EINVAL;
 433
 434	irq = irq_create_mapping(adap->host_notify_domain, client->addr);
 435
 436	return irq > 0 ? irq : -ENXIO;
 437}
 438
 439static int i2c_device_probe(struct device *dev)
 440{
 441	struct i2c_client	*client = i2c_verify_client(dev);
 442	struct i2c_driver	*driver;
 443	int status;
 444
 445	if (!client)
 446		return 0;
 447
 
 
 448	client->irq = client->init_irq;
 449
 450	if (!client->irq) {
 451		int irq = -ENOENT;
 452
 453		if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 454			dev_dbg(dev, "Using Host Notify IRQ\n");
 455			/* Keep adapter active when Host Notify is required */
 456			pm_runtime_get_sync(&client->adapter->dev);
 457			irq = i2c_smbus_host_notify_to_irq(client);
 458		} else if (dev->of_node) {
 459			irq = of_irq_get_byname(dev->of_node, "irq");
 460			if (irq == -EINVAL || irq == -ENODATA)
 461				irq = of_irq_get(dev->of_node, 0);
 462		} else if (ACPI_COMPANION(dev)) {
 463			irq = i2c_acpi_get_irq(client);
 464		}
 465		if (irq == -EPROBE_DEFER) {
 466			status = irq;
 467			goto put_sync_adapter;
 468		}
 469
 470		if (irq < 0)
 471			irq = 0;
 472
 473		client->irq = irq;
 474	}
 475
 476	driver = to_i2c_driver(dev->driver);
 477
 478	/*
 479	 * An I2C ID table is not mandatory, if and only if, a suitable OF
 480	 * or ACPI ID table is supplied for the probing device.
 481	 */
 482	if (!driver->id_table &&
 483	    !acpi_driver_match_device(dev, dev->driver) &&
 484	    !i2c_of_match_device(dev->driver->of_match_table, client)) {
 485		status = -ENODEV;
 486		goto put_sync_adapter;
 487	}
 488
 489	if (client->flags & I2C_CLIENT_WAKE) {
 490		int wakeirq;
 491
 492		wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 493		if (wakeirq == -EPROBE_DEFER) {
 494			status = wakeirq;
 495			goto put_sync_adapter;
 496		}
 497
 498		device_init_wakeup(&client->dev, true);
 499
 500		if (wakeirq > 0 && wakeirq != client->irq)
 501			status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 502		else if (client->irq > 0)
 503			status = dev_pm_set_wake_irq(dev, client->irq);
 504		else
 505			status = 0;
 506
 507		if (status)
 508			dev_warn(&client->dev, "failed to set up wakeup irq\n");
 509	}
 510
 511	dev_dbg(dev, "probe\n");
 512
 513	status = of_clk_set_defaults(dev->of_node, false);
 514	if (status < 0)
 515		goto err_clear_wakeup_irq;
 516
 517	status = dev_pm_domain_attach(&client->dev, true);
 518	if (status)
 519		goto err_clear_wakeup_irq;
 520
 521	/*
 522	 * When there are no more users of probe(),
 523	 * rename probe_new to probe.
 524	 */
 525	if (driver->probe_new)
 526		status = driver->probe_new(client);
 527	else if (driver->probe)
 528		status = driver->probe(client,
 529				       i2c_match_id(driver->id_table, client));
 530	else
 531		status = -EINVAL;
 532
 533	if (status)
 534		goto err_detach_pm_domain;
 535
 536	return 0;
 537
 538err_detach_pm_domain:
 539	dev_pm_domain_detach(&client->dev, true);
 540err_clear_wakeup_irq:
 541	dev_pm_clear_wake_irq(&client->dev);
 542	device_init_wakeup(&client->dev, false);
 543put_sync_adapter:
 544	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 545		pm_runtime_put_sync(&client->adapter->dev);
 546
 547	return status;
 548}
 549
 550static int i2c_device_remove(struct device *dev)
 551{
 552	struct i2c_client	*client = i2c_verify_client(dev);
 553	struct i2c_driver	*driver;
 554	int status = 0;
 555
 556	if (!client || !dev->driver)
 557		return 0;
 558
 559	driver = to_i2c_driver(dev->driver);
 560	if (driver->remove) {
 561		dev_dbg(dev, "remove\n");
 562		status = driver->remove(client);
 563	}
 564
 565	dev_pm_domain_detach(&client->dev, true);
 566
 567	dev_pm_clear_wake_irq(&client->dev);
 568	device_init_wakeup(&client->dev, false);
 569
 570	client->irq = 0;
 571	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 572		pm_runtime_put(&client->adapter->dev);
 573
 574	return status;
 575}
 576
 577static void i2c_device_shutdown(struct device *dev)
 578{
 579	struct i2c_client *client = i2c_verify_client(dev);
 580	struct i2c_driver *driver;
 581
 582	if (!client || !dev->driver)
 583		return;
 584	driver = to_i2c_driver(dev->driver);
 585	if (driver->shutdown)
 586		driver->shutdown(client);
 587}
 588
 589static void i2c_client_dev_release(struct device *dev)
 590{
 591	kfree(to_i2c_client(dev));
 592}
 593
 594static ssize_t
 595name_show(struct device *dev, struct device_attribute *attr, char *buf)
 596{
 597	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 598		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 599}
 600static DEVICE_ATTR_RO(name);
 601
 602static ssize_t
 603modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
 604{
 605	struct i2c_client *client = to_i2c_client(dev);
 606	int len;
 607
 608	len = of_device_modalias(dev, buf, PAGE_SIZE);
 609	if (len != -ENODEV)
 610		return len;
 611
 612	len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 613	if (len != -ENODEV)
 614		return len;
 615
 616	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 617}
 618static DEVICE_ATTR_RO(modalias);
 619
 620static struct attribute *i2c_dev_attrs[] = {
 621	&dev_attr_name.attr,
 622	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
 623	&dev_attr_modalias.attr,
 624	NULL
 625};
 626ATTRIBUTE_GROUPS(i2c_dev);
 627
 628struct bus_type i2c_bus_type = {
 629	.name		= "i2c",
 630	.match		= i2c_device_match,
 631	.probe		= i2c_device_probe,
 632	.remove		= i2c_device_remove,
 633	.shutdown	= i2c_device_shutdown,
 634};
 635EXPORT_SYMBOL_GPL(i2c_bus_type);
 636
 637struct device_type i2c_client_type = {
 638	.groups		= i2c_dev_groups,
 639	.uevent		= i2c_device_uevent,
 640	.release	= i2c_client_dev_release,
 641};
 642EXPORT_SYMBOL_GPL(i2c_client_type);
 643
 644
 645/**
 646 * i2c_verify_client - return parameter as i2c_client, or NULL
 647 * @dev: device, probably from some driver model iterator
 648 *
 649 * When traversing the driver model tree, perhaps using driver model
 650 * iterators like @device_for_each_child(), you can't assume very much
 651 * about the nodes you find.  Use this function to avoid oopses caused
 652 * by wrongly treating some non-I2C device as an i2c_client.
 653 */
 654struct i2c_client *i2c_verify_client(struct device *dev)
 655{
 656	return (dev->type == &i2c_client_type)
 657			? to_i2c_client(dev)
 658			: NULL;
 659}
 660EXPORT_SYMBOL(i2c_verify_client);
 661
 662
 663/* Return a unique address which takes the flags of the client into account */
 664static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 665{
 666	unsigned short addr = client->addr;
 667
 668	/* For some client flags, add an arbitrary offset to avoid collisions */
 669	if (client->flags & I2C_CLIENT_TEN)
 670		addr |= I2C_ADDR_OFFSET_TEN_BIT;
 671
 672	if (client->flags & I2C_CLIENT_SLAVE)
 673		addr |= I2C_ADDR_OFFSET_SLAVE;
 674
 675	return addr;
 676}
 677
 678/* This is a permissive address validity check, I2C address map constraints
 679 * are purposely not enforced, except for the general call address. */
 680static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 681{
 682	if (flags & I2C_CLIENT_TEN) {
 683		/* 10-bit address, all values are valid */
 684		if (addr > 0x3ff)
 685			return -EINVAL;
 686	} else {
 687		/* 7-bit address, reject the general call address */
 688		if (addr == 0x00 || addr > 0x7f)
 689			return -EINVAL;
 690	}
 691	return 0;
 692}
 693
 694/* And this is a strict address validity check, used when probing. If a
 695 * device uses a reserved address, then it shouldn't be probed. 7-bit
 696 * addressing is assumed, 10-bit address devices are rare and should be
 697 * explicitly enumerated. */
 698int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 699{
 700	/*
 701	 * Reserved addresses per I2C specification:
 702	 *  0x00       General call address / START byte
 703	 *  0x01       CBUS address
 704	 *  0x02       Reserved for different bus format
 705	 *  0x03       Reserved for future purposes
 706	 *  0x04-0x07  Hs-mode master code
 707	 *  0x78-0x7b  10-bit slave addressing
 708	 *  0x7c-0x7f  Reserved for future purposes
 709	 */
 710	if (addr < 0x08 || addr > 0x77)
 711		return -EINVAL;
 712	return 0;
 713}
 714
 715static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 716{
 717	struct i2c_client	*client = i2c_verify_client(dev);
 718	int			addr = *(int *)addrp;
 719
 720	if (client && i2c_encode_flags_to_addr(client) == addr)
 721		return -EBUSY;
 722	return 0;
 723}
 724
 725/* walk up mux tree */
 726static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 727{
 728	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 729	int result;
 730
 731	result = device_for_each_child(&adapter->dev, &addr,
 732					__i2c_check_addr_busy);
 733
 734	if (!result && parent)
 735		result = i2c_check_mux_parents(parent, addr);
 736
 737	return result;
 738}
 739
 740/* recurse down mux tree */
 741static int i2c_check_mux_children(struct device *dev, void *addrp)
 742{
 743	int result;
 744
 745	if (dev->type == &i2c_adapter_type)
 746		result = device_for_each_child(dev, addrp,
 747						i2c_check_mux_children);
 748	else
 749		result = __i2c_check_addr_busy(dev, addrp);
 750
 751	return result;
 752}
 753
 754static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 755{
 756	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 757	int result = 0;
 758
 759	if (parent)
 760		result = i2c_check_mux_parents(parent, addr);
 761
 762	if (!result)
 763		result = device_for_each_child(&adapter->dev, &addr,
 764						i2c_check_mux_children);
 765
 766	return result;
 767}
 768
 769/**
 770 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 771 * @adapter: Target I2C bus segment
 772 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 773 *	locks only this branch in the adapter tree
 774 */
 775static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 776				 unsigned int flags)
 777{
 778	rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
 779}
 780
 781/**
 782 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 783 * @adapter: Target I2C bus segment
 784 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 785 *	trylocks only this branch in the adapter tree
 786 */
 787static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 788				   unsigned int flags)
 789{
 790	return rt_mutex_trylock(&adapter->bus_lock);
 791}
 792
 793/**
 794 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 795 * @adapter: Target I2C bus segment
 796 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 797 *	unlocks only this branch in the adapter tree
 798 */
 799static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 800				   unsigned int flags)
 801{
 802	rt_mutex_unlock(&adapter->bus_lock);
 803}
 804
 805static void i2c_dev_set_name(struct i2c_adapter *adap,
 806			     struct i2c_client *client,
 807			     struct i2c_board_info const *info)
 808{
 809	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 810
 811	if (info && info->dev_name) {
 812		dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 813		return;
 814	}
 815
 816	if (adev) {
 817		dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 818		return;
 819	}
 820
 821	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 822		     i2c_encode_flags_to_addr(client));
 823}
 824
 825int i2c_dev_irq_from_resources(const struct resource *resources,
 826			       unsigned int num_resources)
 827{
 828	struct irq_data *irqd;
 829	int i;
 830
 831	for (i = 0; i < num_resources; i++) {
 832		const struct resource *r = &resources[i];
 833
 834		if (resource_type(r) != IORESOURCE_IRQ)
 835			continue;
 836
 837		if (r->flags & IORESOURCE_BITS) {
 838			irqd = irq_get_irq_data(r->start);
 839			if (!irqd)
 840				break;
 841
 842			irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 843		}
 844
 845		return r->start;
 846	}
 847
 848	return 0;
 849}
 850
 851/**
 852 * i2c_new_client_device - instantiate an i2c device
 853 * @adap: the adapter managing the device
 854 * @info: describes one I2C device; bus_num is ignored
 855 * Context: can sleep
 856 *
 857 * Create an i2c device. Binding is handled through driver model
 858 * probe()/remove() methods.  A driver may be bound to this device when we
 859 * return from this function, or any later moment (e.g. maybe hotplugging will
 860 * load the driver module).  This call is not appropriate for use by mainboard
 861 * initialization logic, which usually runs during an arch_initcall() long
 862 * before any i2c_adapter could exist.
 863 *
 864 * This returns the new i2c client, which may be saved for later use with
 865 * i2c_unregister_device(); or an ERR_PTR to describe the error.
 866 */
 867struct i2c_client *
 868i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 869{
 870	struct i2c_client	*client;
 871	int			status;
 872
 873	client = kzalloc(sizeof *client, GFP_KERNEL);
 874	if (!client)
 875		return ERR_PTR(-ENOMEM);
 876
 877	client->adapter = adap;
 878
 879	client->dev.platform_data = info->platform_data;
 880	client->flags = info->flags;
 881	client->addr = info->addr;
 882
 883	client->init_irq = info->irq;
 884	if (!client->init_irq)
 885		client->init_irq = i2c_dev_irq_from_resources(info->resources,
 886							 info->num_resources);
 887
 888	strlcpy(client->name, info->type, sizeof(client->name));
 889
 890	status = i2c_check_addr_validity(client->addr, client->flags);
 891	if (status) {
 892		dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 893			client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 894		goto out_err_silent;
 895	}
 896
 897	/* Check for address business */
 898	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 899	if (status)
 900		goto out_err;
 901
 902	client->dev.parent = &client->adapter->dev;
 903	client->dev.bus = &i2c_bus_type;
 904	client->dev.type = &i2c_client_type;
 905	client->dev.of_node = of_node_get(info->of_node);
 906	client->dev.fwnode = info->fwnode;
 907
 908	i2c_dev_set_name(adap, client, info);
 909
 910	if (info->properties) {
 911		status = device_add_properties(&client->dev, info->properties);
 912		if (status) {
 913			dev_err(&adap->dev,
 914				"Failed to add properties to client %s: %d\n",
 915				client->name, status);
 916			goto out_err_put_of_node;
 917		}
 918	}
 919
 920	status = device_register(&client->dev);
 921	if (status)
 922		goto out_free_props;
 923
 924	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 925		client->name, dev_name(&client->dev));
 926
 927	return client;
 928
 929out_free_props:
 930	if (info->properties)
 931		device_remove_properties(&client->dev);
 932out_err_put_of_node:
 933	of_node_put(info->of_node);
 934out_err:
 935	dev_err(&adap->dev,
 936		"Failed to register i2c client %s at 0x%02x (%d)\n",
 937		client->name, client->addr, status);
 938out_err_silent:
 939	kfree(client);
 940	return ERR_PTR(status);
 941}
 942EXPORT_SYMBOL_GPL(i2c_new_client_device);
 943
 944/**
 945 * i2c_unregister_device - reverse effect of i2c_new_*_device()
 946 * @client: value returned from i2c_new_*_device()
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 947 * Context: can sleep
 948 */
 949void i2c_unregister_device(struct i2c_client *client)
 950{
 951	if (IS_ERR_OR_NULL(client))
 952		return;
 953
 954	if (client->dev.of_node) {
 955		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 956		of_node_put(client->dev.of_node);
 957	}
 958
 959	if (ACPI_COMPANION(&client->dev))
 960		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 961	device_unregister(&client->dev);
 962}
 963EXPORT_SYMBOL_GPL(i2c_unregister_device);
 964
 965
 966static const struct i2c_device_id dummy_id[] = {
 967	{ "dummy", 0 },
 968	{ },
 969};
 970
 971static int dummy_probe(struct i2c_client *client,
 972		       const struct i2c_device_id *id)
 973{
 974	return 0;
 975}
 976
 977static int dummy_remove(struct i2c_client *client)
 978{
 979	return 0;
 980}
 981
 982static struct i2c_driver dummy_driver = {
 983	.driver.name	= "dummy",
 984	.probe		= dummy_probe,
 985	.remove		= dummy_remove,
 986	.id_table	= dummy_id,
 987};
 988
 989/**
 990 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
 991 * @adapter: the adapter managing the device
 992 * @address: seven bit address to be used
 993 * Context: can sleep
 994 *
 995 * This returns an I2C client bound to the "dummy" driver, intended for use
 996 * with devices that consume multiple addresses.  Examples of such chips
 997 * include various EEPROMS (like 24c04 and 24c08 models).
 998 *
 999 * These dummy devices have two main uses.  First, most I2C and SMBus calls
1000 * except i2c_transfer() need a client handle; the dummy will be that handle.
1001 * And second, this prevents the specified address from being bound to a
1002 * different driver.
1003 *
1004 * This returns the new i2c client, which should be saved for later use with
1005 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1006 */
1007struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1008{
1009	struct i2c_board_info info = {
1010		I2C_BOARD_INFO("dummy", address),
1011	};
1012
1013	return i2c_new_client_device(adapter, &info);
1014}
1015EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1016
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1017struct i2c_dummy_devres {
1018	struct i2c_client *client;
1019};
1020
1021static void devm_i2c_release_dummy(struct device *dev, void *res)
1022{
1023	struct i2c_dummy_devres *this = res;
1024
1025	i2c_unregister_device(this->client);
1026}
1027
1028/**
1029 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1030 * @dev: device the managed resource is bound to
1031 * @adapter: the adapter managing the device
1032 * @address: seven bit address to be used
1033 * Context: can sleep
1034 *
1035 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1036 * new i2c client or an ERR_PTR in case of an error.
1037 */
1038struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1039					     struct i2c_adapter *adapter,
1040					     u16 address)
1041{
1042	struct i2c_dummy_devres *dr;
1043	struct i2c_client *client;
1044
1045	dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
1046	if (!dr)
1047		return ERR_PTR(-ENOMEM);
1048
1049	client = i2c_new_dummy_device(adapter, address);
1050	if (IS_ERR(client)) {
1051		devres_free(dr);
1052	} else {
1053		dr->client = client;
1054		devres_add(dev, dr);
1055	}
1056
1057	return client;
1058}
1059EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1060
1061/**
1062 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1063 * and create the associated device
1064 * @client: Handle to the primary client
1065 * @name: Handle to specify which secondary address to get
1066 * @default_addr: Used as a fallback if no secondary address was specified
1067 * Context: can sleep
1068 *
1069 * I2C clients can be composed of multiple I2C slaves bound together in a single
1070 * component. The I2C client driver then binds to the master I2C slave and needs
1071 * to create I2C dummy clients to communicate with all the other slaves.
1072 *
1073 * This function creates and returns an I2C dummy client whose I2C address is
1074 * retrieved from the platform firmware based on the given slave name. If no
1075 * address is specified by the firmware default_addr is used.
1076 *
1077 * On DT-based platforms the address is retrieved from the "reg" property entry
1078 * cell whose "reg-names" value matches the slave name.
1079 *
1080 * This returns the new i2c client, which should be saved for later use with
1081 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1082 */
1083struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1084						const char *name,
1085						u16 default_addr)
1086{
1087	struct device_node *np = client->dev.of_node;
1088	u32 addr = default_addr;
1089	int i;
1090
1091	if (np) {
1092		i = of_property_match_string(np, "reg-names", name);
1093		if (i >= 0)
1094			of_property_read_u32_index(np, "reg", i, &addr);
1095	}
1096
1097	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1098	return i2c_new_dummy_device(client->adapter, addr);
1099}
1100EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1101
1102/* ------------------------------------------------------------------------- */
1103
1104/* I2C bus adapters -- one roots each I2C or SMBUS segment */
1105
1106static void i2c_adapter_dev_release(struct device *dev)
1107{
1108	struct i2c_adapter *adap = to_i2c_adapter(dev);
1109	complete(&adap->dev_released);
1110}
1111
1112unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1113{
1114	unsigned int depth = 0;
1115
1116	while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1117		depth++;
1118
1119	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1120		  "adapter depth exceeds lockdep subclass limit\n");
1121
1122	return depth;
1123}
1124EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1125
1126/*
1127 * Let users instantiate I2C devices through sysfs. This can be used when
1128 * platform initialization code doesn't contain the proper data for
1129 * whatever reason. Also useful for drivers that do device detection and
1130 * detection fails, either because the device uses an unexpected address,
1131 * or this is a compatible device with different ID register values.
1132 *
1133 * Parameter checking may look overzealous, but we really don't want
1134 * the user to provide incorrect parameters.
1135 */
1136static ssize_t
1137new_device_store(struct device *dev, struct device_attribute *attr,
1138		 const char *buf, size_t count)
1139{
1140	struct i2c_adapter *adap = to_i2c_adapter(dev);
1141	struct i2c_board_info info;
1142	struct i2c_client *client;
1143	char *blank, end;
1144	int res;
1145
1146	memset(&info, 0, sizeof(struct i2c_board_info));
1147
1148	blank = strchr(buf, ' ');
1149	if (!blank) {
1150		dev_err(dev, "%s: Missing parameters\n", "new_device");
1151		return -EINVAL;
1152	}
1153	if (blank - buf > I2C_NAME_SIZE - 1) {
1154		dev_err(dev, "%s: Invalid device name\n", "new_device");
1155		return -EINVAL;
1156	}
1157	memcpy(info.type, buf, blank - buf);
1158
1159	/* Parse remaining parameters, reject extra parameters */
1160	res = sscanf(++blank, "%hi%c", &info.addr, &end);
1161	if (res < 1) {
1162		dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1163		return -EINVAL;
1164	}
1165	if (res > 1  && end != '\n') {
1166		dev_err(dev, "%s: Extra parameters\n", "new_device");
1167		return -EINVAL;
1168	}
1169
1170	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1171		info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1172		info.flags |= I2C_CLIENT_TEN;
1173	}
1174
1175	if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1176		info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1177		info.flags |= I2C_CLIENT_SLAVE;
1178	}
1179
1180	client = i2c_new_client_device(adap, &info);
1181	if (IS_ERR(client))
1182		return PTR_ERR(client);
1183
1184	/* Keep track of the added device */
1185	mutex_lock(&adap->userspace_clients_lock);
1186	list_add_tail(&client->detected, &adap->userspace_clients);
1187	mutex_unlock(&adap->userspace_clients_lock);
1188	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1189		 info.type, info.addr);
1190
1191	return count;
1192}
1193static DEVICE_ATTR_WO(new_device);
1194
1195/*
1196 * And of course let the users delete the devices they instantiated, if
1197 * they got it wrong. This interface can only be used to delete devices
1198 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1199 * don't delete devices to which some kernel code still has references.
1200 *
1201 * Parameter checking may look overzealous, but we really don't want
1202 * the user to delete the wrong device.
1203 */
1204static ssize_t
1205delete_device_store(struct device *dev, struct device_attribute *attr,
1206		    const char *buf, size_t count)
1207{
1208	struct i2c_adapter *adap = to_i2c_adapter(dev);
1209	struct i2c_client *client, *next;
1210	unsigned short addr;
1211	char end;
1212	int res;
1213
1214	/* Parse parameters, reject extra parameters */
1215	res = sscanf(buf, "%hi%c", &addr, &end);
1216	if (res < 1) {
1217		dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1218		return -EINVAL;
1219	}
1220	if (res > 1  && end != '\n') {
1221		dev_err(dev, "%s: Extra parameters\n", "delete_device");
1222		return -EINVAL;
1223	}
1224
1225	/* Make sure the device was added through sysfs */
1226	res = -ENOENT;
1227	mutex_lock_nested(&adap->userspace_clients_lock,
1228			  i2c_adapter_depth(adap));
1229	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1230				 detected) {
1231		if (i2c_encode_flags_to_addr(client) == addr) {
1232			dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1233				 "delete_device", client->name, client->addr);
1234
1235			list_del(&client->detected);
1236			i2c_unregister_device(client);
1237			res = count;
1238			break;
1239		}
1240	}
1241	mutex_unlock(&adap->userspace_clients_lock);
1242
1243	if (res < 0)
1244		dev_err(dev, "%s: Can't find device in list\n",
1245			"delete_device");
1246	return res;
1247}
1248static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1249				  delete_device_store);
1250
1251static struct attribute *i2c_adapter_attrs[] = {
1252	&dev_attr_name.attr,
1253	&dev_attr_new_device.attr,
1254	&dev_attr_delete_device.attr,
1255	NULL
1256};
1257ATTRIBUTE_GROUPS(i2c_adapter);
1258
1259struct device_type i2c_adapter_type = {
1260	.groups		= i2c_adapter_groups,
1261	.release	= i2c_adapter_dev_release,
1262};
1263EXPORT_SYMBOL_GPL(i2c_adapter_type);
1264
1265/**
1266 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1267 * @dev: device, probably from some driver model iterator
1268 *
1269 * When traversing the driver model tree, perhaps using driver model
1270 * iterators like @device_for_each_child(), you can't assume very much
1271 * about the nodes you find.  Use this function to avoid oopses caused
1272 * by wrongly treating some non-I2C device as an i2c_adapter.
1273 */
1274struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1275{
1276	return (dev->type == &i2c_adapter_type)
1277			? to_i2c_adapter(dev)
1278			: NULL;
1279}
1280EXPORT_SYMBOL(i2c_verify_adapter);
1281
1282#ifdef CONFIG_I2C_COMPAT
1283static struct class_compat *i2c_adapter_compat_class;
1284#endif
1285
1286static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1287{
1288	struct i2c_devinfo	*devinfo;
1289
1290	down_read(&__i2c_board_lock);
1291	list_for_each_entry(devinfo, &__i2c_board_list, list) {
1292		if (devinfo->busnum == adapter->nr &&
1293		    IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
 
1294			dev_err(&adapter->dev,
1295				"Can't create device at 0x%02x\n",
1296				devinfo->board_info.addr);
1297	}
1298	up_read(&__i2c_board_lock);
1299}
1300
1301static int i2c_do_add_adapter(struct i2c_driver *driver,
1302			      struct i2c_adapter *adap)
1303{
1304	/* Detect supported devices on that bus, and instantiate them */
1305	i2c_detect(adap, driver);
1306
1307	return 0;
1308}
1309
1310static int __process_new_adapter(struct device_driver *d, void *data)
1311{
1312	return i2c_do_add_adapter(to_i2c_driver(d), data);
1313}
1314
1315static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1316	.lock_bus =    i2c_adapter_lock_bus,
1317	.trylock_bus = i2c_adapter_trylock_bus,
1318	.unlock_bus =  i2c_adapter_unlock_bus,
1319};
1320
1321static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1322{
1323	struct irq_domain *domain = adap->host_notify_domain;
1324	irq_hw_number_t hwirq;
1325
1326	if (!domain)
1327		return;
1328
1329	for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1330		irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1331
1332	irq_domain_remove(domain);
1333	adap->host_notify_domain = NULL;
1334}
1335
1336static int i2c_host_notify_irq_map(struct irq_domain *h,
1337					  unsigned int virq,
1338					  irq_hw_number_t hw_irq_num)
1339{
1340	irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1341
1342	return 0;
1343}
1344
1345static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1346	.map = i2c_host_notify_irq_map,
1347};
1348
1349static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1350{
1351	struct irq_domain *domain;
1352
1353	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1354		return 0;
1355
1356	domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1357					  I2C_ADDR_7BITS_COUNT,
1358					  &i2c_host_notify_irq_ops, adap);
1359	if (!domain)
1360		return -ENOMEM;
1361
1362	adap->host_notify_domain = domain;
1363
1364	return 0;
1365}
1366
1367/**
1368 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1369 * I2C client.
1370 * @adap: the adapter
1371 * @addr: the I2C address of the notifying device
1372 * Context: can't sleep
1373 *
1374 * Helper function to be called from an I2C bus driver's interrupt
1375 * handler. It will schedule the Host Notify IRQ.
1376 */
1377int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1378{
1379	int irq;
1380
1381	if (!adap)
1382		return -EINVAL;
1383
1384	irq = irq_find_mapping(adap->host_notify_domain, addr);
1385	if (irq <= 0)
1386		return -ENXIO;
1387
1388	generic_handle_irq(irq);
1389
1390	return 0;
1391}
1392EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1393
1394static int i2c_register_adapter(struct i2c_adapter *adap)
1395{
1396	int res = -EINVAL;
1397
1398	/* Can't register until after driver model init */
1399	if (WARN_ON(!is_registered)) {
1400		res = -EAGAIN;
1401		goto out_list;
1402	}
1403
1404	/* Sanity checks */
1405	if (WARN(!adap->name[0], "i2c adapter has no name"))
1406		goto out_list;
1407
1408	if (!adap->algo) {
1409		pr_err("adapter '%s': no algo supplied!\n", adap->name);
1410		goto out_list;
1411	}
1412
1413	if (!adap->lock_ops)
1414		adap->lock_ops = &i2c_adapter_lock_ops;
1415
1416	adap->locked_flags = 0;
1417	rt_mutex_init(&adap->bus_lock);
1418	rt_mutex_init(&adap->mux_lock);
1419	mutex_init(&adap->userspace_clients_lock);
1420	INIT_LIST_HEAD(&adap->userspace_clients);
1421
1422	/* Set default timeout to 1 second if not already set */
1423	if (adap->timeout == 0)
1424		adap->timeout = HZ;
1425
1426	/* register soft irqs for Host Notify */
1427	res = i2c_setup_host_notify_irq_domain(adap);
1428	if (res) {
1429		pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1430		       adap->name, res);
1431		goto out_list;
1432	}
1433
1434	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1435	adap->dev.bus = &i2c_bus_type;
1436	adap->dev.type = &i2c_adapter_type;
1437	res = device_register(&adap->dev);
1438	if (res) {
1439		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1440		goto out_list;
1441	}
1442
1443	res = of_i2c_setup_smbus_alert(adap);
1444	if (res)
1445		goto out_reg;
1446
 
 
1447	pm_runtime_no_callbacks(&adap->dev);
1448	pm_suspend_ignore_children(&adap->dev, true);
1449	pm_runtime_enable(&adap->dev);
1450
1451	res = i2c_init_recovery(adap);
1452	if (res == -EPROBE_DEFER)
1453		goto out_reg;
1454
1455	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1456
1457#ifdef CONFIG_I2C_COMPAT
1458	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1459				       adap->dev.parent);
1460	if (res)
1461		dev_warn(&adap->dev,
1462			 "Failed to create compatibility class link\n");
1463#endif
1464
 
 
1465	/* create pre-declared device nodes */
1466	of_i2c_register_devices(adap);
1467	i2c_acpi_install_space_handler(adap);
1468	i2c_acpi_register_devices(adap);
 
1469
1470	if (adap->nr < __i2c_first_dynamic_bus_num)
1471		i2c_scan_static_board_info(adap);
1472
1473	/* Notify drivers */
1474	mutex_lock(&core_lock);
1475	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1476	mutex_unlock(&core_lock);
1477
1478	return 0;
1479
1480out_reg:
1481	init_completion(&adap->dev_released);
1482	device_unregister(&adap->dev);
1483	wait_for_completion(&adap->dev_released);
1484out_list:
1485	mutex_lock(&core_lock);
1486	idr_remove(&i2c_adapter_idr, adap->nr);
1487	mutex_unlock(&core_lock);
1488	return res;
1489}
1490
1491/**
1492 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1493 * @adap: the adapter to register (with adap->nr initialized)
1494 * Context: can sleep
1495 *
1496 * See i2c_add_numbered_adapter() for details.
1497 */
1498static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1499{
1500	int id;
1501
1502	mutex_lock(&core_lock);
1503	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1504	mutex_unlock(&core_lock);
1505	if (WARN(id < 0, "couldn't get idr"))
1506		return id == -ENOSPC ? -EBUSY : id;
1507
1508	return i2c_register_adapter(adap);
1509}
1510
1511/**
1512 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1513 * @adapter: the adapter to add
1514 * Context: can sleep
1515 *
1516 * This routine is used to declare an I2C adapter when its bus number
1517 * doesn't matter or when its bus number is specified by an dt alias.
1518 * Examples of bases when the bus number doesn't matter: I2C adapters
1519 * dynamically added by USB links or PCI plugin cards.
1520 *
1521 * When this returns zero, a new bus number was allocated and stored
1522 * in adap->nr, and the specified adapter became available for clients.
1523 * Otherwise, a negative errno value is returned.
1524 */
1525int i2c_add_adapter(struct i2c_adapter *adapter)
1526{
1527	struct device *dev = &adapter->dev;
1528	int id;
1529
1530	if (dev->of_node) {
1531		id = of_alias_get_id(dev->of_node, "i2c");
1532		if (id >= 0) {
1533			adapter->nr = id;
1534			return __i2c_add_numbered_adapter(adapter);
1535		}
1536	}
1537
1538	mutex_lock(&core_lock);
1539	id = idr_alloc(&i2c_adapter_idr, adapter,
1540		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1541	mutex_unlock(&core_lock);
1542	if (WARN(id < 0, "couldn't get idr"))
1543		return id;
1544
1545	adapter->nr = id;
1546
1547	return i2c_register_adapter(adapter);
1548}
1549EXPORT_SYMBOL(i2c_add_adapter);
1550
1551/**
1552 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1553 * @adap: the adapter to register (with adap->nr initialized)
1554 * Context: can sleep
1555 *
1556 * This routine is used to declare an I2C adapter when its bus number
1557 * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1558 * or otherwise built in to the system's mainboard, and where i2c_board_info
1559 * is used to properly configure I2C devices.
1560 *
1561 * If the requested bus number is set to -1, then this function will behave
1562 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1563 *
1564 * If no devices have pre-been declared for this bus, then be sure to
1565 * register the adapter before any dynamically allocated ones.  Otherwise
1566 * the required bus ID may not be available.
1567 *
1568 * When this returns zero, the specified adapter became available for
1569 * clients using the bus number provided in adap->nr.  Also, the table
1570 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1571 * and the appropriate driver model device nodes are created.  Otherwise, a
1572 * negative errno value is returned.
1573 */
1574int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1575{
1576	if (adap->nr == -1) /* -1 means dynamically assign bus id */
1577		return i2c_add_adapter(adap);
1578
1579	return __i2c_add_numbered_adapter(adap);
1580}
1581EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1582
1583static void i2c_do_del_adapter(struct i2c_driver *driver,
1584			      struct i2c_adapter *adapter)
1585{
1586	struct i2c_client *client, *_n;
1587
1588	/* Remove the devices we created ourselves as the result of hardware
1589	 * probing (using a driver's detect method) */
1590	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1591		if (client->adapter == adapter) {
1592			dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1593				client->name, client->addr);
1594			list_del(&client->detected);
1595			i2c_unregister_device(client);
1596		}
1597	}
1598}
1599
1600static int __unregister_client(struct device *dev, void *dummy)
1601{
1602	struct i2c_client *client = i2c_verify_client(dev);
1603	if (client && strcmp(client->name, "dummy"))
1604		i2c_unregister_device(client);
1605	return 0;
1606}
1607
1608static int __unregister_dummy(struct device *dev, void *dummy)
1609{
1610	struct i2c_client *client = i2c_verify_client(dev);
1611	i2c_unregister_device(client);
1612	return 0;
1613}
1614
1615static int __process_removed_adapter(struct device_driver *d, void *data)
1616{
1617	i2c_do_del_adapter(to_i2c_driver(d), data);
1618	return 0;
1619}
1620
1621/**
1622 * i2c_del_adapter - unregister I2C adapter
1623 * @adap: the adapter being unregistered
1624 * Context: can sleep
1625 *
1626 * This unregisters an I2C adapter which was previously registered
1627 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1628 */
1629void i2c_del_adapter(struct i2c_adapter *adap)
1630{
1631	struct i2c_adapter *found;
1632	struct i2c_client *client, *next;
1633
1634	/* First make sure that this adapter was ever added */
1635	mutex_lock(&core_lock);
1636	found = idr_find(&i2c_adapter_idr, adap->nr);
1637	mutex_unlock(&core_lock);
1638	if (found != adap) {
1639		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1640		return;
1641	}
1642
1643	i2c_acpi_remove_space_handler(adap);
1644	/* Tell drivers about this removal */
1645	mutex_lock(&core_lock);
1646	bus_for_each_drv(&i2c_bus_type, NULL, adap,
1647			       __process_removed_adapter);
1648	mutex_unlock(&core_lock);
1649
1650	/* Remove devices instantiated from sysfs */
1651	mutex_lock_nested(&adap->userspace_clients_lock,
1652			  i2c_adapter_depth(adap));
1653	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1654				 detected) {
1655		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1656			client->addr);
1657		list_del(&client->detected);
1658		i2c_unregister_device(client);
1659	}
1660	mutex_unlock(&adap->userspace_clients_lock);
1661
1662	/* Detach any active clients. This can't fail, thus we do not
1663	 * check the returned value. This is a two-pass process, because
1664	 * we can't remove the dummy devices during the first pass: they
1665	 * could have been instantiated by real devices wishing to clean
1666	 * them up properly, so we give them a chance to do that first. */
1667	device_for_each_child(&adap->dev, NULL, __unregister_client);
1668	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1669
1670#ifdef CONFIG_I2C_COMPAT
1671	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1672				 adap->dev.parent);
1673#endif
1674
1675	/* device name is gone after device_unregister */
1676	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1677
1678	pm_runtime_disable(&adap->dev);
1679
1680	i2c_host_notify_irq_teardown(adap);
1681
1682	/* wait until all references to the device are gone
1683	 *
1684	 * FIXME: This is old code and should ideally be replaced by an
1685	 * alternative which results in decoupling the lifetime of the struct
1686	 * device from the i2c_adapter, like spi or netdev do. Any solution
1687	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1688	 */
1689	init_completion(&adap->dev_released);
1690	device_unregister(&adap->dev);
1691	wait_for_completion(&adap->dev_released);
1692
1693	/* free bus id */
1694	mutex_lock(&core_lock);
1695	idr_remove(&i2c_adapter_idr, adap->nr);
1696	mutex_unlock(&core_lock);
1697
1698	/* Clear the device structure in case this adapter is ever going to be
1699	   added again */
1700	memset(&adap->dev, 0, sizeof(adap->dev));
1701}
1702EXPORT_SYMBOL(i2c_del_adapter);
1703
1704static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1705			    u32 def_val, bool use_def)
1706{
1707	int ret;
1708
1709	ret = device_property_read_u32(dev, prop_name, cur_val_p);
1710	if (ret && use_def)
1711		*cur_val_p = def_val;
1712
1713	dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1714}
1715
1716/**
1717 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1718 * @dev: The device to scan for I2C timing properties
1719 * @t: the i2c_timings struct to be filled with values
1720 * @use_defaults: bool to use sane defaults derived from the I2C specification
1721 *		  when properties are not found, otherwise don't update
1722 *
1723 * Scan the device for the generic I2C properties describing timing parameters
1724 * for the signal and fill the given struct with the results. If a property was
1725 * not found and use_defaults was true, then maximum timings are assumed which
1726 * are derived from the I2C specification. If use_defaults is not used, the
1727 * results will be as before, so drivers can apply their own defaults before
1728 * calling this helper. The latter is mainly intended for avoiding regressions
1729 * of existing drivers which want to switch to this function. New drivers
1730 * almost always should use the defaults.
1731 */
 
1732void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1733{
1734	bool u = use_defaults;
1735	u32 d;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1736
1737	i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1738			 I2C_MAX_STANDARD_MODE_FREQ, u);
1739
1740	d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1741	    t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1742	i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1743
1744	d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1745	i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1746
1747	i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1748			 &t->scl_int_delay_ns, 0, u);
1749	i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1750			 t->scl_fall_ns, u);
1751	i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1752	i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1753			 &t->digital_filter_width_ns, 0, u);
1754	i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1755			 &t->analog_filter_cutoff_freq_hz, 0, u);
1756}
1757EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1758
1759/* ------------------------------------------------------------------------- */
1760
1761int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1762{
1763	int res;
1764
1765	mutex_lock(&core_lock);
1766	res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1767	mutex_unlock(&core_lock);
1768
1769	return res;
1770}
1771EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1772
1773static int __process_new_driver(struct device *dev, void *data)
1774{
1775	if (dev->type != &i2c_adapter_type)
1776		return 0;
1777	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1778}
1779
1780/*
1781 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1782 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1783 */
1784
1785int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1786{
1787	int res;
1788
1789	/* Can't register until after driver model init */
1790	if (WARN_ON(!is_registered))
1791		return -EAGAIN;
1792
1793	/* add the driver to the list of i2c drivers in the driver core */
1794	driver->driver.owner = owner;
1795	driver->driver.bus = &i2c_bus_type;
1796	INIT_LIST_HEAD(&driver->clients);
1797
1798	/* When registration returns, the driver core
1799	 * will have called probe() for all matching-but-unbound devices.
1800	 */
1801	res = driver_register(&driver->driver);
1802	if (res)
1803		return res;
1804
1805	pr_debug("driver [%s] registered\n", driver->driver.name);
1806
1807	/* Walk the adapters that are already present */
1808	i2c_for_each_dev(driver, __process_new_driver);
1809
1810	return 0;
1811}
1812EXPORT_SYMBOL(i2c_register_driver);
1813
1814static int __process_removed_driver(struct device *dev, void *data)
1815{
1816	if (dev->type == &i2c_adapter_type)
1817		i2c_do_del_adapter(data, to_i2c_adapter(dev));
1818	return 0;
1819}
1820
1821/**
1822 * i2c_del_driver - unregister I2C driver
1823 * @driver: the driver being unregistered
1824 * Context: can sleep
1825 */
1826void i2c_del_driver(struct i2c_driver *driver)
1827{
1828	i2c_for_each_dev(driver, __process_removed_driver);
1829
1830	driver_unregister(&driver->driver);
1831	pr_debug("driver [%s] unregistered\n", driver->driver.name);
1832}
1833EXPORT_SYMBOL(i2c_del_driver);
1834
1835/* ------------------------------------------------------------------------- */
1836
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1837struct i2c_cmd_arg {
1838	unsigned	cmd;
1839	void		*arg;
1840};
1841
1842static int i2c_cmd(struct device *dev, void *_arg)
1843{
1844	struct i2c_client	*client = i2c_verify_client(dev);
1845	struct i2c_cmd_arg	*arg = _arg;
1846	struct i2c_driver	*driver;
1847
1848	if (!client || !client->dev.driver)
1849		return 0;
1850
1851	driver = to_i2c_driver(client->dev.driver);
1852	if (driver->command)
1853		driver->command(client, arg->cmd, arg->arg);
1854	return 0;
1855}
1856
1857void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1858{
1859	struct i2c_cmd_arg	cmd_arg;
1860
1861	cmd_arg.cmd = cmd;
1862	cmd_arg.arg = arg;
1863	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1864}
1865EXPORT_SYMBOL(i2c_clients_command);
1866
1867static int __init i2c_init(void)
1868{
1869	int retval;
1870
1871	retval = of_alias_get_highest_id("i2c");
1872
1873	down_write(&__i2c_board_lock);
1874	if (retval >= __i2c_first_dynamic_bus_num)
1875		__i2c_first_dynamic_bus_num = retval + 1;
1876	up_write(&__i2c_board_lock);
1877
1878	retval = bus_register(&i2c_bus_type);
1879	if (retval)
1880		return retval;
1881
1882	is_registered = true;
1883
1884#ifdef CONFIG_I2C_COMPAT
1885	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1886	if (!i2c_adapter_compat_class) {
1887		retval = -ENOMEM;
1888		goto bus_err;
1889	}
1890#endif
1891	retval = i2c_add_driver(&dummy_driver);
1892	if (retval)
1893		goto class_err;
1894
1895	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1896		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1897	if (IS_ENABLED(CONFIG_ACPI))
1898		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1899
1900	return 0;
1901
1902class_err:
1903#ifdef CONFIG_I2C_COMPAT
1904	class_compat_unregister(i2c_adapter_compat_class);
1905bus_err:
1906#endif
1907	is_registered = false;
1908	bus_unregister(&i2c_bus_type);
1909	return retval;
1910}
1911
1912static void __exit i2c_exit(void)
1913{
1914	if (IS_ENABLED(CONFIG_ACPI))
1915		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1916	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1917		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1918	i2c_del_driver(&dummy_driver);
1919#ifdef CONFIG_I2C_COMPAT
1920	class_compat_unregister(i2c_adapter_compat_class);
1921#endif
1922	bus_unregister(&i2c_bus_type);
1923	tracepoint_synchronize_unregister();
1924}
1925
1926/* We must initialize early, because some subsystems register i2c drivers
1927 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1928 */
1929postcore_initcall(i2c_init);
1930module_exit(i2c_exit);
1931
1932/* ----------------------------------------------------
1933 * the functional interface to the i2c busses.
1934 * ----------------------------------------------------
1935 */
1936
1937/* Check if val is exceeding the quirk IFF quirk is non 0 */
1938#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1939
1940static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1941{
1942	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1943			    err_msg, msg->addr, msg->len,
1944			    msg->flags & I2C_M_RD ? "read" : "write");
1945	return -EOPNOTSUPP;
1946}
1947
1948static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1949{
1950	const struct i2c_adapter_quirks *q = adap->quirks;
1951	int max_num = q->max_num_msgs, i;
1952	bool do_len_check = true;
1953
1954	if (q->flags & I2C_AQ_COMB) {
1955		max_num = 2;
1956
1957		/* special checks for combined messages */
1958		if (num == 2) {
1959			if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1960				return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1961
1962			if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1963				return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1964
1965			if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1966				return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1967
1968			if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1969				return i2c_quirk_error(adap, &msgs[0], "msg too long");
1970
1971			if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1972				return i2c_quirk_error(adap, &msgs[1], "msg too long");
1973
1974			do_len_check = false;
1975		}
1976	}
1977
1978	if (i2c_quirk_exceeded(num, max_num))
1979		return i2c_quirk_error(adap, &msgs[0], "too many messages");
1980
1981	for (i = 0; i < num; i++) {
1982		u16 len = msgs[i].len;
1983
1984		if (msgs[i].flags & I2C_M_RD) {
1985			if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1986				return i2c_quirk_error(adap, &msgs[i], "msg too long");
1987
1988			if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1989				return i2c_quirk_error(adap, &msgs[i], "no zero length");
1990		} else {
1991			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1992				return i2c_quirk_error(adap, &msgs[i], "msg too long");
1993
1994			if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1995				return i2c_quirk_error(adap, &msgs[i], "no zero length");
1996		}
1997	}
1998
1999	return 0;
2000}
2001
2002/**
2003 * __i2c_transfer - unlocked flavor of i2c_transfer
2004 * @adap: Handle to I2C bus
2005 * @msgs: One or more messages to execute before STOP is issued to
2006 *	terminate the operation; each message begins with a START.
2007 * @num: Number of messages to be executed.
2008 *
2009 * Returns negative errno, else the number of messages executed.
2010 *
2011 * Adapter lock must be held when calling this function. No debug logging
2012 * takes place. adap->algo->master_xfer existence isn't checked.
2013 */
2014int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2015{
2016	unsigned long orig_jiffies;
2017	int ret, try;
2018
2019	if (WARN_ON(!msgs || num < 1))
2020		return -EINVAL;
2021
2022	ret = __i2c_check_suspended(adap);
2023	if (ret)
2024		return ret;
2025
2026	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2027		return -EOPNOTSUPP;
2028
2029	/*
2030	 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2031	 * enabled.  This is an efficient way of keeping the for-loop from
2032	 * being executed when not needed.
2033	 */
2034	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2035		int i;
2036		for (i = 0; i < num; i++)
2037			if (msgs[i].flags & I2C_M_RD)
2038				trace_i2c_read(adap, &msgs[i], i);
2039			else
2040				trace_i2c_write(adap, &msgs[i], i);
2041	}
2042
2043	/* Retry automatically on arbitration loss */
2044	orig_jiffies = jiffies;
2045	for (ret = 0, try = 0; try <= adap->retries; try++) {
2046		if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2047			ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2048		else
2049			ret = adap->algo->master_xfer(adap, msgs, num);
2050
2051		if (ret != -EAGAIN)
2052			break;
2053		if (time_after(jiffies, orig_jiffies + adap->timeout))
2054			break;
2055	}
2056
2057	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2058		int i;
2059		for (i = 0; i < ret; i++)
2060			if (msgs[i].flags & I2C_M_RD)
2061				trace_i2c_reply(adap, &msgs[i], i);
2062		trace_i2c_result(adap, num, ret);
2063	}
2064
2065	return ret;
2066}
2067EXPORT_SYMBOL(__i2c_transfer);
2068
2069/**
2070 * i2c_transfer - execute a single or combined I2C message
2071 * @adap: Handle to I2C bus
2072 * @msgs: One or more messages to execute before STOP is issued to
2073 *	terminate the operation; each message begins with a START.
2074 * @num: Number of messages to be executed.
2075 *
2076 * Returns negative errno, else the number of messages executed.
2077 *
2078 * Note that there is no requirement that each message be sent to
2079 * the same slave address, although that is the most common model.
2080 */
2081int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2082{
2083	int ret;
2084
2085	if (!adap->algo->master_xfer) {
2086		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2087		return -EOPNOTSUPP;
2088	}
2089
2090	/* REVISIT the fault reporting model here is weak:
2091	 *
2092	 *  - When we get an error after receiving N bytes from a slave,
2093	 *    there is no way to report "N".
2094	 *
2095	 *  - When we get a NAK after transmitting N bytes to a slave,
2096	 *    there is no way to report "N" ... or to let the master
2097	 *    continue executing the rest of this combined message, if
2098	 *    that's the appropriate response.
2099	 *
2100	 *  - When for example "num" is two and we successfully complete
2101	 *    the first message but get an error part way through the
2102	 *    second, it's unclear whether that should be reported as
2103	 *    one (discarding status on the second message) or errno
2104	 *    (discarding status on the first one).
2105	 */
2106	ret = __i2c_lock_bus_helper(adap);
2107	if (ret)
2108		return ret;
2109
2110	ret = __i2c_transfer(adap, msgs, num);
2111	i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2112
2113	return ret;
2114}
2115EXPORT_SYMBOL(i2c_transfer);
2116
2117/**
2118 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2119 *			       to/from a buffer
2120 * @client: Handle to slave device
2121 * @buf: Where the data is stored
2122 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2123 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2124 *
2125 * Returns negative errno, or else the number of bytes transferred.
2126 */
2127int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2128			      int count, u16 flags)
2129{
2130	int ret;
2131	struct i2c_msg msg = {
2132		.addr = client->addr,
2133		.flags = flags | (client->flags & I2C_M_TEN),
2134		.len = count,
2135		.buf = buf,
2136	};
2137
2138	ret = i2c_transfer(client->adapter, &msg, 1);
2139
2140	/*
2141	 * If everything went ok (i.e. 1 msg transferred), return #bytes
2142	 * transferred, else error code.
2143	 */
2144	return (ret == 1) ? count : ret;
2145}
2146EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2147
2148/**
2149 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2150 * @client: The device to query
2151 * @id: The queried information
2152 *
2153 * Returns negative errno on error, zero on success.
2154 */
2155int i2c_get_device_id(const struct i2c_client *client,
2156		      struct i2c_device_identity *id)
2157{
2158	struct i2c_adapter *adap = client->adapter;
2159	union i2c_smbus_data raw_id;
2160	int ret;
2161
2162	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2163		return -EOPNOTSUPP;
2164
2165	raw_id.block[0] = 3;
2166	ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2167			     I2C_SMBUS_READ, client->addr << 1,
2168			     I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2169	if (ret)
2170		return ret;
2171
2172	id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2173	id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2174	id->die_revision = raw_id.block[3] & 0x7;
2175	return 0;
2176}
2177EXPORT_SYMBOL_GPL(i2c_get_device_id);
2178
2179/* ----------------------------------------------------
2180 * the i2c address scanning function
2181 * Will not work for 10-bit addresses!
2182 * ----------------------------------------------------
2183 */
2184
2185/*
2186 * Legacy default probe function, mostly relevant for SMBus. The default
2187 * probe method is a quick write, but it is known to corrupt the 24RF08
2188 * EEPROMs due to a state machine bug, and could also irreversibly
2189 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2190 * we use a short byte read instead. Also, some bus drivers don't implement
2191 * quick write, so we fallback to a byte read in that case too.
2192 * On x86, there is another special case for FSC hardware monitoring chips,
2193 * which want regular byte reads (address 0x73.) Fortunately, these are the
2194 * only known chips using this I2C address on PC hardware.
2195 * Returns 1 if probe succeeded, 0 if not.
2196 */
2197static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2198{
2199	int err;
2200	union i2c_smbus_data dummy;
2201
2202#ifdef CONFIG_X86
2203	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2204	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2205		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2206				     I2C_SMBUS_BYTE_DATA, &dummy);
2207	else
2208#endif
2209	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2210	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2211		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2212				     I2C_SMBUS_QUICK, NULL);
2213	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2214		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2215				     I2C_SMBUS_BYTE, &dummy);
2216	else {
2217		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2218			 addr);
2219		err = -EOPNOTSUPP;
2220	}
2221
2222	return err >= 0;
2223}
2224
2225static int i2c_detect_address(struct i2c_client *temp_client,
2226			      struct i2c_driver *driver)
2227{
2228	struct i2c_board_info info;
2229	struct i2c_adapter *adapter = temp_client->adapter;
2230	int addr = temp_client->addr;
2231	int err;
2232
2233	/* Make sure the address is valid */
2234	err = i2c_check_7bit_addr_validity_strict(addr);
2235	if (err) {
2236		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2237			 addr);
2238		return err;
2239	}
2240
2241	/* Skip if already in use (7 bit, no need to encode flags) */
2242	if (i2c_check_addr_busy(adapter, addr))
2243		return 0;
2244
2245	/* Make sure there is something at this address */
2246	if (!i2c_default_probe(adapter, addr))
2247		return 0;
2248
2249	/* Finally call the custom detection function */
2250	memset(&info, 0, sizeof(struct i2c_board_info));
2251	info.addr = addr;
2252	err = driver->detect(temp_client, &info);
2253	if (err) {
2254		/* -ENODEV is returned if the detection fails. We catch it
2255		   here as this isn't an error. */
2256		return err == -ENODEV ? 0 : err;
2257	}
2258
2259	/* Consistency check */
2260	if (info.type[0] == '\0') {
2261		dev_err(&adapter->dev,
2262			"%s detection function provided no name for 0x%x\n",
2263			driver->driver.name, addr);
2264	} else {
2265		struct i2c_client *client;
2266
2267		/* Detection succeeded, instantiate the device */
2268		if (adapter->class & I2C_CLASS_DEPRECATED)
2269			dev_warn(&adapter->dev,
2270				"This adapter will soon drop class based instantiation of devices. "
2271				"Please make sure client 0x%02x gets instantiated by other means. "
2272				"Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2273				info.addr);
2274
2275		dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2276			info.type, info.addr);
2277		client = i2c_new_client_device(adapter, &info);
2278		if (!IS_ERR(client))
2279			list_add_tail(&client->detected, &driver->clients);
2280		else
2281			dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2282				info.type, info.addr);
2283	}
2284	return 0;
2285}
2286
2287static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2288{
2289	const unsigned short *address_list;
2290	struct i2c_client *temp_client;
2291	int i, err = 0;
 
2292
2293	address_list = driver->address_list;
2294	if (!driver->detect || !address_list)
2295		return 0;
2296
2297	/* Warn that the adapter lost class based instantiation */
2298	if (adapter->class == I2C_CLASS_DEPRECATED) {
2299		dev_dbg(&adapter->dev,
2300			"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2301			"If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2302			driver->driver.name);
2303		return 0;
2304	}
2305
2306	/* Stop here if the classes do not match */
2307	if (!(adapter->class & driver->class))
2308		return 0;
2309
2310	/* Set up a temporary client to help detect callback */
2311	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2312	if (!temp_client)
2313		return -ENOMEM;
2314	temp_client->adapter = adapter;
2315
2316	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2317		dev_dbg(&adapter->dev,
2318			"found normal entry for adapter %d, addr 0x%02x\n",
2319			i2c_adapter_id(adapter), address_list[i]);
2320		temp_client->addr = address_list[i];
2321		err = i2c_detect_address(temp_client, driver);
2322		if (unlikely(err))
2323			break;
2324	}
2325
2326	kfree(temp_client);
2327	return err;
2328}
2329
2330int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2331{
2332	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2333			      I2C_SMBUS_QUICK, NULL) >= 0;
2334}
2335EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2336
2337struct i2c_client *
2338i2c_new_scanned_device(struct i2c_adapter *adap,
2339		       struct i2c_board_info *info,
2340		       unsigned short const *addr_list,
2341		       int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2342{
2343	int i;
2344
2345	if (!probe)
2346		probe = i2c_default_probe;
2347
2348	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2349		/* Check address validity */
2350		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2351			dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2352				 addr_list[i]);
2353			continue;
2354		}
2355
2356		/* Check address availability (7 bit, no need to encode flags) */
2357		if (i2c_check_addr_busy(adap, addr_list[i])) {
2358			dev_dbg(&adap->dev,
2359				"Address 0x%02x already in use, not probing\n",
2360				addr_list[i]);
2361			continue;
2362		}
2363
2364		/* Test address responsiveness */
2365		if (probe(adap, addr_list[i]))
2366			break;
2367	}
2368
2369	if (addr_list[i] == I2C_CLIENT_END) {
2370		dev_dbg(&adap->dev, "Probing failed, no device found\n");
2371		return ERR_PTR(-ENODEV);
2372	}
2373
2374	info->addr = addr_list[i];
2375	return i2c_new_client_device(adap, info);
2376}
2377EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2378
2379struct i2c_adapter *i2c_get_adapter(int nr)
2380{
2381	struct i2c_adapter *adapter;
2382
2383	mutex_lock(&core_lock);
2384	adapter = idr_find(&i2c_adapter_idr, nr);
2385	if (!adapter)
2386		goto exit;
2387
2388	if (try_module_get(adapter->owner))
2389		get_device(&adapter->dev);
2390	else
2391		adapter = NULL;
2392
2393 exit:
2394	mutex_unlock(&core_lock);
2395	return adapter;
2396}
2397EXPORT_SYMBOL(i2c_get_adapter);
2398
2399void i2c_put_adapter(struct i2c_adapter *adap)
2400{
2401	if (!adap)
2402		return;
2403
2404	put_device(&adap->dev);
2405	module_put(adap->owner);
2406}
2407EXPORT_SYMBOL(i2c_put_adapter);
2408
2409/**
2410 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2411 * @msg: the message to be checked
2412 * @threshold: the minimum number of bytes for which using DMA makes sense.
2413 *	       Should at least be 1.
2414 *
2415 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2416 *	   Or a valid pointer to be used with DMA. After use, release it by
2417 *	   calling i2c_put_dma_safe_msg_buf().
2418 *
2419 * This function must only be called from process context!
2420 */
2421u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2422{
2423	/* also skip 0-length msgs for bogus thresholds of 0 */
2424	if (!threshold)
2425		pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2426			 msg->addr);
2427	if (msg->len < threshold || msg->len == 0)
2428		return NULL;
2429
2430	if (msg->flags & I2C_M_DMA_SAFE)
2431		return msg->buf;
2432
2433	pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2434		 msg->addr, msg->len);
2435
2436	if (msg->flags & I2C_M_RD)
2437		return kzalloc(msg->len, GFP_KERNEL);
2438	else
2439		return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2440}
2441EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2442
2443/**
2444 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2445 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2446 * @msg: the message which the buffer corresponds to
2447 * @xferred: bool saying if the message was transferred
2448 */
2449void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2450{
2451	if (!buf || buf == msg->buf)
2452		return;
2453
2454	if (xferred && msg->flags & I2C_M_RD)
2455		memcpy(msg->buf, buf, msg->len);
2456
2457	kfree(buf);
2458}
2459EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2460
2461MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2462MODULE_DESCRIPTION("I2C-Bus main module");
2463MODULE_LICENSE("GPL");