1/*
   2 * Linux I2C core
   3 *
   4 * Copyright (C) 1995-99 Simon G. Vogl
   5 *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
   6 *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   7 *   Michael Lawnick <michael.lawnick.ext@nsn.com>
   8 *
   9 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
  10 *
  11 * This program is free software; you can redistribute it and/or modify it
  12 * under the terms of the GNU General Public License as published by the Free
  13 * Software Foundation; either version 2 of the License, or (at your option)
  14 * any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful, but WITHOUT
  17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
  19 */
  20
  21#define pr_fmt(fmt) "i2c-core: " fmt
  22
  23#include <dt-bindings/i2c/i2c.h>
  24#include <linux/acpi.h>
  25#include <linux/clk/clk-conf.h>
  26#include <linux/completion.h>
  27#include <linux/delay.h>
  28#include <linux/err.h>
  29#include <linux/errno.h>
  30#include <linux/gpio/consumer.h>
  31#include <linux/i2c.h>
  32#include <linux/i2c-smbus.h>
  33#include <linux/idr.h>
  34#include <linux/init.h>
  35#include <linux/irqflags.h>
  36#include <linux/jump_label.h>
  37#include <linux/kernel.h>
  38#include <linux/module.h>
  39#include <linux/mutex.h>
  40#include <linux/of_device.h>
  41#include <linux/of.h>
  42#include <linux/of_irq.h>
  43#include <linux/pm_domain.h>
  44#include <linux/pm_runtime.h>
  45#include <linux/pm_wakeirq.h>
  46#include <linux/property.h>
  47#include <linux/rwsem.h>
  48#include <linux/slab.h>
  49
  50#include "i2c-core.h"
  51
  52#define CREATE_TRACE_POINTS
  53#include <trace/events/i2c.h>
  54
  55#define I2C_ADDR_OFFSET_TEN_BIT	0xa000
  56#define I2C_ADDR_OFFSET_SLAVE	0x1000
  57
  58#define I2C_ADDR_7BITS_MAX	0x77
  59#define I2C_ADDR_7BITS_COUNT	(I2C_ADDR_7BITS_MAX + 1)
  60
  61#define I2C_ADDR_DEVICE_ID	0x7c
  62
  63/*
  64 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  65 * deletion of detected devices, and attach_adapter calls are serialized
  66 */
  67static DEFINE_MUTEX(core_lock);
  68static DEFINE_IDR(i2c_adapter_idr);
  69
  70static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  71
  72static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
  73static bool is_registered;
  74
  75int i2c_transfer_trace_reg(void)
  76{
  77	static_branch_inc(&i2c_trace_msg_key);
  78	return 0;
  79}
  80
  81void i2c_transfer_trace_unreg(void)
  82{
  83	static_branch_dec(&i2c_trace_msg_key);
  84}
  85
  86const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  87						const struct i2c_client *client)
  88{
  89	if (!(id && client))
  90		return NULL;
  91
  92	while (id->name[0]) {
  93		if (strcmp(client->name, id->name) == 0)
  94			return id;
  95		id++;
  96	}
  97	return NULL;
  98}
  99EXPORT_SYMBOL_GPL(i2c_match_id);
 100
 101static int i2c_device_match(struct device *dev, struct device_driver *drv)
 102{
 103	struct i2c_client	*client = i2c_verify_client(dev);
 104	struct i2c_driver	*driver;
 105
 106
 107	/* Attempt an OF style match */
 108	if (i2c_of_match_device(drv->of_match_table, client))
 109		return 1;
 110
 111	/* Then ACPI style match */
 112	if (acpi_driver_match_device(dev, drv))
 113		return 1;
 114
 115	driver = to_i2c_driver(drv);
 116
 117	/* Finally an I2C match */
 118	if (i2c_match_id(driver->id_table, client))
 119		return 1;
 120
 121	return 0;
 122}
 123
 124static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 125{
 126	struct i2c_client *client = to_i2c_client(dev);
 127	int rc;
 128
 129	rc = of_device_uevent_modalias(dev, env);
 130	if (rc != -ENODEV)
 131		return rc;
 132
 133	rc = acpi_device_uevent_modalias(dev, env);
 134	if (rc != -ENODEV)
 135		return rc;
 136
 137	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 138}
 139
 140/* i2c bus recovery routines */
 141static int get_scl_gpio_value(struct i2c_adapter *adap)
 142{
 143	return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
 144}
 145
 146static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 147{
 148	gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
 149}
 150
 151static int get_sda_gpio_value(struct i2c_adapter *adap)
 152{
 153	return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
 154}
 155
 156static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
 157{
 158	gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
 159}
 160
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 161/*
 162 * We are generating clock pulses. ndelay() determines durating of clk pulses.
 163 * We will generate clock with rate 100 KHz and so duration of both clock levels
 164 * is: delay in ns = (10^6 / 100) / 2
 165 */
 166#define RECOVERY_NDELAY		5000
 167#define RECOVERY_CLK_CNT	9
 168
 169int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 170{
 171	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 172	int i = 0, val = 1, ret = 0;
 173
 174	if (bri->prepare_recovery)
 175		bri->prepare_recovery(adap);
 176
 177	bri->set_scl(adap, val);
 
 
 
 
 
 
 
 178	if (bri->set_sda)
 179		bri->set_sda(adap, 1);
 180	ndelay(RECOVERY_NDELAY);
 181
 182	/*
 183	 * By this time SCL is high, as we need to give 9 falling-rising edges
 184	 */
 185	while (i++ < RECOVERY_CLK_CNT * 2) {
 186		if (val) {
 187			/* SCL shouldn't be low here */
 188			if (!bri->get_scl(adap)) {
 189				dev_err(&adap->dev,
 190					"SCL is stuck low, exit recovery\n");
 191				ret = -EBUSY;
 192				break;
 193			}
 194			/* Break if SDA is high */
 195			if (bri->get_sda && bri->get_sda(adap))
 196				break;
 197		}
 198
 199		val = !val;
 200		bri->set_scl(adap, val);
 201		ndelay(RECOVERY_NDELAY);
 202	}
 203
 204	/* check if recovery actually succeeded */
 205	if (bri->get_sda && !bri->get_sda(adap))
 206		ret = -EBUSY;
 207
 208	/* If all went well, send STOP for a sane bus state. */
 209	if (ret == 0 && bri->set_sda) {
 210		bri->set_scl(adap, 0);
 211		ndelay(RECOVERY_NDELAY / 2);
 212		bri->set_sda(adap, 0);
 213		ndelay(RECOVERY_NDELAY / 2);
 214		bri->set_scl(adap, 1);
 215		ndelay(RECOVERY_NDELAY / 2);
 216		bri->set_sda(adap, 1);
 
 217		ndelay(RECOVERY_NDELAY / 2);
 
 
 
 
 
 
 218	}
 219
 
 
 
 
 220	if (bri->unprepare_recovery)
 221		bri->unprepare_recovery(adap);
 222
 223	return ret;
 224}
 225EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 226
 227int i2c_recover_bus(struct i2c_adapter *adap)
 228{
 229	if (!adap->bus_recovery_info)
 230		return -EOPNOTSUPP;
 231
 232	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 233	return adap->bus_recovery_info->recover_bus(adap);
 234}
 235EXPORT_SYMBOL_GPL(i2c_recover_bus);
 236
 237static void i2c_init_recovery(struct i2c_adapter *adap)
 238{
 239	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 240	char *err_str;
 241
 242	if (!bri)
 243		return;
 244
 245	if (!bri->recover_bus) {
 246		err_str = "no recover_bus() found";
 247		goto err;
 248	}
 249
 250	if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 251		bri->get_scl = get_scl_gpio_value;
 252		bri->set_scl = set_scl_gpio_value;
 253		if (bri->sda_gpiod) {
 254			bri->get_sda = get_sda_gpio_value;
 255			/* FIXME: add proper flag instead of '0' once available */
 256			if (gpiod_get_direction(bri->sda_gpiod) == 0)
 257				bri->set_sda = set_sda_gpio_value;
 258		}
 259		return;
 260	}
 261
 262	if (bri->recover_bus == i2c_generic_scl_recovery) {
 263		/* Generic SCL recovery */
 264		if (!bri->set_scl || !bri->get_scl) {
 265			err_str = "no {get|set}_scl() found";
 266			goto err;
 267		}
 
 
 
 
 268	}
 269
 270	return;
 271 err:
 272	dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 273	adap->bus_recovery_info = NULL;
 274}
 275
 276static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 277{
 278	struct i2c_adapter *adap = client->adapter;
 279	unsigned int irq;
 280
 281	if (!adap->host_notify_domain)
 282		return -ENXIO;
 283
 284	if (client->flags & I2C_CLIENT_TEN)
 285		return -EINVAL;
 286
 287	irq = irq_find_mapping(adap->host_notify_domain, client->addr);
 288	if (!irq)
 289		irq = irq_create_mapping(adap->host_notify_domain,
 290					 client->addr);
 291
 292	return irq > 0 ? irq : -ENXIO;
 293}
 294
 295static int i2c_device_probe(struct device *dev)
 296{
 297	struct i2c_client	*client = i2c_verify_client(dev);
 298	struct i2c_driver	*driver;
 299	int status;
 300
 301	if (!client)
 302		return 0;
 303
 304	driver = to_i2c_driver(dev->driver);
 305
 
 
 306	if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 307		int irq = -ENOENT;
 308
 309		if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 310			dev_dbg(dev, "Using Host Notify IRQ\n");
 
 
 311			irq = i2c_smbus_host_notify_to_irq(client);
 312		} else if (dev->of_node) {
 313			irq = of_irq_get_byname(dev->of_node, "irq");
 314			if (irq == -EINVAL || irq == -ENODATA)
 315				irq = of_irq_get(dev->of_node, 0);
 316		} else if (ACPI_COMPANION(dev)) {
 317			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 318		}
 319		if (irq == -EPROBE_DEFER)
 320			return irq;
 321
 322		if (irq < 0)
 323			irq = 0;
 324
 325		client->irq = irq;
 326	}
 327
 328	/*
 329	 * An I2C ID table is not mandatory, if and only if, a suitable OF
 330	 * or ACPI ID table is supplied for the probing device.
 331	 */
 332	if (!driver->id_table &&
 333	    !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 334	    !i2c_of_match_device(dev->driver->of_match_table, client))
 335		return -ENODEV;
 336
 337	if (client->flags & I2C_CLIENT_WAKE) {
 338		int wakeirq = -ENOENT;
 339
 340		if (dev->of_node) {
 341			wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 342			if (wakeirq == -EPROBE_DEFER)
 343				return wakeirq;
 344		}
 345
 346		device_init_wakeup(&client->dev, true);
 347
 348		if (wakeirq > 0 && wakeirq != client->irq)
 349			status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 350		else if (client->irq > 0)
 351			status = dev_pm_set_wake_irq(dev, client->irq);
 352		else
 353			status = 0;
 354
 355		if (status)
 356			dev_warn(&client->dev, "failed to set up wakeup irq\n");
 357	}
 358
 359	dev_dbg(dev, "probe\n");
 360
 361	status = of_clk_set_defaults(dev->of_node, false);
 362	if (status < 0)
 363		goto err_clear_wakeup_irq;
 364
 365	status = dev_pm_domain_attach(&client->dev, true);
 366	if (status == -EPROBE_DEFER)
 367		goto err_clear_wakeup_irq;
 368
 369	/*
 370	 * When there are no more users of probe(),
 371	 * rename probe_new to probe.
 372	 */
 373	if (driver->probe_new)
 374		status = driver->probe_new(client);
 375	else if (driver->probe)
 376		status = driver->probe(client,
 377				       i2c_match_id(driver->id_table, client));
 378	else
 379		status = -EINVAL;
 380
 381	if (status)
 382		goto err_detach_pm_domain;
 383
 384	return 0;
 385
 386err_detach_pm_domain:
 387	dev_pm_domain_detach(&client->dev, true);
 388err_clear_wakeup_irq:
 389	dev_pm_clear_wake_irq(&client->dev);
 390	device_init_wakeup(&client->dev, false);
 391	return status;
 392}
 393
 394static int i2c_device_remove(struct device *dev)
 395{
 396	struct i2c_client	*client = i2c_verify_client(dev);
 397	struct i2c_driver	*driver;
 398	int status = 0;
 399
 400	if (!client || !dev->driver)
 401		return 0;
 402
 403	driver = to_i2c_driver(dev->driver);
 404	if (driver->remove) {
 405		dev_dbg(dev, "remove\n");
 406		status = driver->remove(client);
 407	}
 408
 409	dev_pm_domain_detach(&client->dev, true);
 410
 411	dev_pm_clear_wake_irq(&client->dev);
 412	device_init_wakeup(&client->dev, false);
 413
 
 
 
 
 414	return status;
 415}
 416
 417static void i2c_device_shutdown(struct device *dev)
 418{
 419	struct i2c_client *client = i2c_verify_client(dev);
 420	struct i2c_driver *driver;
 421
 422	if (!client || !dev->driver)
 423		return;
 424	driver = to_i2c_driver(dev->driver);
 425	if (driver->shutdown)
 426		driver->shutdown(client);
 427}
 428
 429static void i2c_client_dev_release(struct device *dev)
 430{
 431	kfree(to_i2c_client(dev));
 432}
 433
 434static ssize_t
 435show_name(struct device *dev, struct device_attribute *attr, char *buf)
 436{
 437	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 438		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 439}
 440static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 441
 442static ssize_t
 443show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 444{
 445	struct i2c_client *client = to_i2c_client(dev);
 446	int len;
 447
 448	len = of_device_modalias(dev, buf, PAGE_SIZE);
 449	if (len != -ENODEV)
 450		return len;
 451
 452	len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 453	if (len != -ENODEV)
 454		return len;
 455
 456	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 457}
 458static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 459
 460static struct attribute *i2c_dev_attrs[] = {
 461	&dev_attr_name.attr,
 462	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
 463	&dev_attr_modalias.attr,
 464	NULL
 465};
 466ATTRIBUTE_GROUPS(i2c_dev);
 467
 468struct bus_type i2c_bus_type = {
 469	.name		= "i2c",
 470	.match		= i2c_device_match,
 471	.probe		= i2c_device_probe,
 472	.remove		= i2c_device_remove,
 473	.shutdown	= i2c_device_shutdown,
 474};
 475EXPORT_SYMBOL_GPL(i2c_bus_type);
 476
 477struct device_type i2c_client_type = {
 478	.groups		= i2c_dev_groups,
 479	.uevent		= i2c_device_uevent,
 480	.release	= i2c_client_dev_release,
 481};
 482EXPORT_SYMBOL_GPL(i2c_client_type);
 483
 484
 485/**
 486 * i2c_verify_client - return parameter as i2c_client, or NULL
 487 * @dev: device, probably from some driver model iterator
 488 *
 489 * When traversing the driver model tree, perhaps using driver model
 490 * iterators like @device_for_each_child(), you can't assume very much
 491 * about the nodes you find.  Use this function to avoid oopses caused
 492 * by wrongly treating some non-I2C device as an i2c_client.
 493 */
 494struct i2c_client *i2c_verify_client(struct device *dev)
 495{
 496	return (dev->type == &i2c_client_type)
 497			? to_i2c_client(dev)
 498			: NULL;
 499}
 500EXPORT_SYMBOL(i2c_verify_client);
 501
 502
 503/* Return a unique address which takes the flags of the client into account */
 504static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 505{
 506	unsigned short addr = client->addr;
 507
 508	/* For some client flags, add an arbitrary offset to avoid collisions */
 509	if (client->flags & I2C_CLIENT_TEN)
 510		addr |= I2C_ADDR_OFFSET_TEN_BIT;
 511
 512	if (client->flags & I2C_CLIENT_SLAVE)
 513		addr |= I2C_ADDR_OFFSET_SLAVE;
 514
 515	return addr;
 516}
 517
 518/* This is a permissive address validity check, I2C address map constraints
 519 * are purposely not enforced, except for the general call address. */
 520static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 521{
 522	if (flags & I2C_CLIENT_TEN) {
 523		/* 10-bit address, all values are valid */
 524		if (addr > 0x3ff)
 525			return -EINVAL;
 526	} else {
 527		/* 7-bit address, reject the general call address */
 528		if (addr == 0x00 || addr > 0x7f)
 529			return -EINVAL;
 530	}
 531	return 0;
 532}
 533
 534/* And this is a strict address validity check, used when probing. If a
 535 * device uses a reserved address, then it shouldn't be probed. 7-bit
 536 * addressing is assumed, 10-bit address devices are rare and should be
 537 * explicitly enumerated. */
 538int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 539{
 540	/*
 541	 * Reserved addresses per I2C specification:
 542	 *  0x00       General call address / START byte
 543	 *  0x01       CBUS address
 544	 *  0x02       Reserved for different bus format
 545	 *  0x03       Reserved for future purposes
 546	 *  0x04-0x07  Hs-mode master code
 547	 *  0x78-0x7b  10-bit slave addressing
 548	 *  0x7c-0x7f  Reserved for future purposes
 549	 */
 550	if (addr < 0x08 || addr > 0x77)
 551		return -EINVAL;
 552	return 0;
 553}
 554
 555static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 556{
 557	struct i2c_client	*client = i2c_verify_client(dev);
 558	int			addr = *(int *)addrp;
 559
 560	if (client && i2c_encode_flags_to_addr(client) == addr)
 561		return -EBUSY;
 562	return 0;
 563}
 564
 565/* walk up mux tree */
 566static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 567{
 568	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 569	int result;
 570
 571	result = device_for_each_child(&adapter->dev, &addr,
 572					__i2c_check_addr_busy);
 573
 574	if (!result && parent)
 575		result = i2c_check_mux_parents(parent, addr);
 576
 577	return result;
 578}
 579
 580/* recurse down mux tree */
 581static int i2c_check_mux_children(struct device *dev, void *addrp)
 582{
 583	int result;
 584
 585	if (dev->type == &i2c_adapter_type)
 586		result = device_for_each_child(dev, addrp,
 587						i2c_check_mux_children);
 588	else
 589		result = __i2c_check_addr_busy(dev, addrp);
 590
 591	return result;
 592}
 593
 594static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 595{
 596	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 597	int result = 0;
 598
 599	if (parent)
 600		result = i2c_check_mux_parents(parent, addr);
 601
 602	if (!result)
 603		result = device_for_each_child(&adapter->dev, &addr,
 604						i2c_check_mux_children);
 605
 606	return result;
 607}
 608
 609/**
 610 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 611 * @adapter: Target I2C bus segment
 612 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 613 *	locks only this branch in the adapter tree
 614 */
 615static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 616				 unsigned int flags)
 617{
 618	rt_mutex_lock(&adapter->bus_lock);
 619}
 620
 621/**
 622 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 623 * @adapter: Target I2C bus segment
 624 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 625 *	trylocks only this branch in the adapter tree
 626 */
 627static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 628				   unsigned int flags)
 629{
 630	return rt_mutex_trylock(&adapter->bus_lock);
 631}
 632
 633/**
 634 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 635 * @adapter: Target I2C bus segment
 636 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 637 *	unlocks only this branch in the adapter tree
 638 */
 639static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 640				   unsigned int flags)
 641{
 642	rt_mutex_unlock(&adapter->bus_lock);
 643}
 644
 645static void i2c_dev_set_name(struct i2c_adapter *adap,
 646			     struct i2c_client *client,
 647			     struct i2c_board_info const *info)
 648{
 649	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 650
 651	if (info && info->dev_name) {
 652		dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 653		return;
 654	}
 655
 656	if (adev) {
 657		dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 658		return;
 659	}
 660
 661	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 662		     i2c_encode_flags_to_addr(client));
 663}
 664
 665static int i2c_dev_irq_from_resources(const struct resource *resources,
 666				      unsigned int num_resources)
 667{
 668	struct irq_data *irqd;
 669	int i;
 670
 671	for (i = 0; i < num_resources; i++) {
 672		const struct resource *r = &resources[i];
 673
 674		if (resource_type(r) != IORESOURCE_IRQ)
 675			continue;
 676
 677		if (r->flags & IORESOURCE_BITS) {
 678			irqd = irq_get_irq_data(r->start);
 679			if (!irqd)
 680				break;
 681
 682			irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 683		}
 684
 685		return r->start;
 686	}
 687
 688	return 0;
 689}
 690
 691/**
 692 * i2c_new_device - instantiate an i2c device
 693 * @adap: the adapter managing the device
 694 * @info: describes one I2C device; bus_num is ignored
 695 * Context: can sleep
 696 *
 697 * Create an i2c device. Binding is handled through driver model
 698 * probe()/remove() methods.  A driver may be bound to this device when we
 699 * return from this function, or any later moment (e.g. maybe hotplugging will
 700 * load the driver module).  This call is not appropriate for use by mainboard
 701 * initialization logic, which usually runs during an arch_initcall() long
 702 * before any i2c_adapter could exist.
 703 *
 704 * This returns the new i2c client, which may be saved for later use with
 705 * i2c_unregister_device(); or NULL to indicate an error.
 706 */
 707struct i2c_client *
 708i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 709{
 710	struct i2c_client	*client;
 711	int			status;
 712
 713	client = kzalloc(sizeof *client, GFP_KERNEL);
 714	if (!client)
 715		return NULL;
 716
 717	client->adapter = adap;
 718
 719	client->dev.platform_data = info->platform_data;
 720
 721	if (info->archdata)
 722		client->dev.archdata = *info->archdata;
 723
 724	client->flags = info->flags;
 725	client->addr = info->addr;
 726
 727	client->irq = info->irq;
 728	if (!client->irq)
 729		client->irq = i2c_dev_irq_from_resources(info->resources,
 730							 info->num_resources);
 731
 732	strlcpy(client->name, info->type, sizeof(client->name));
 733
 734	status = i2c_check_addr_validity(client->addr, client->flags);
 735	if (status) {
 736		dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 737			client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 738		goto out_err_silent;
 739	}
 740
 741	/* Check for address business */
 742	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 743	if (status)
 744		goto out_err;
 745
 746	client->dev.parent = &client->adapter->dev;
 747	client->dev.bus = &i2c_bus_type;
 748	client->dev.type = &i2c_client_type;
 749	client->dev.of_node = info->of_node;
 750	client->dev.fwnode = info->fwnode;
 751
 752	i2c_dev_set_name(adap, client, info);
 753
 754	if (info->properties) {
 755		status = device_add_properties(&client->dev, info->properties);
 756		if (status) {
 757			dev_err(&adap->dev,
 758				"Failed to add properties to client %s: %d\n",
 759				client->name, status);
 760			goto out_err;
 761		}
 762	}
 763
 764	status = device_register(&client->dev);
 765	if (status)
 766		goto out_free_props;
 767
 768	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 769		client->name, dev_name(&client->dev));
 770
 771	return client;
 772
 773out_free_props:
 774	if (info->properties)
 775		device_remove_properties(&client->dev);
 
 
 776out_err:
 777	dev_err(&adap->dev,
 778		"Failed to register i2c client %s at 0x%02x (%d)\n",
 779		client->name, client->addr, status);
 780out_err_silent:
 781	kfree(client);
 782	return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 783}
 784EXPORT_SYMBOL_GPL(i2c_new_device);
 785
 786
 787/**
 788 * i2c_unregister_device - reverse effect of i2c_new_device()
 789 * @client: value returned from i2c_new_device()
 790 * Context: can sleep
 791 */
 792void i2c_unregister_device(struct i2c_client *client)
 793{
 794	if (!client)
 795		return;
 796
 797	if (client->dev.of_node) {
 798		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 799		of_node_put(client->dev.of_node);
 800	}
 801
 802	if (ACPI_COMPANION(&client->dev))
 803		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 804	device_unregister(&client->dev);
 805}
 806EXPORT_SYMBOL_GPL(i2c_unregister_device);
 807
 808
 809static const struct i2c_device_id dummy_id[] = {
 810	{ "dummy", 0 },
 811	{ },
 812};
 813
 814static int dummy_probe(struct i2c_client *client,
 815		       const struct i2c_device_id *id)
 816{
 817	return 0;
 818}
 819
 820static int dummy_remove(struct i2c_client *client)
 821{
 822	return 0;
 823}
 824
 825static struct i2c_driver dummy_driver = {
 826	.driver.name	= "dummy",
 827	.probe		= dummy_probe,
 828	.remove		= dummy_remove,
 829	.id_table	= dummy_id,
 830};
 831
 832/**
 833 * i2c_new_dummy - return a new i2c device bound to a dummy driver
 834 * @adapter: the adapter managing the device
 835 * @address: seven bit address to be used
 836 * Context: can sleep
 837 *
 838 * This returns an I2C client bound to the "dummy" driver, intended for use
 839 * with devices that consume multiple addresses.  Examples of such chips
 840 * include various EEPROMS (like 24c04 and 24c08 models).
 841 *
 842 * These dummy devices have two main uses.  First, most I2C and SMBus calls
 843 * except i2c_transfer() need a client handle; the dummy will be that handle.
 844 * And second, this prevents the specified address from being bound to a
 845 * different driver.
 846 *
 847 * This returns the new i2c client, which should be saved for later use with
 848 * i2c_unregister_device(); or NULL to indicate an error.
 849 */
 850struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 851{
 852	struct i2c_board_info info = {
 853		I2C_BOARD_INFO("dummy", address),
 854	};
 855
 856	return i2c_new_device(adapter, &info);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 857}
 858EXPORT_SYMBOL_GPL(i2c_new_dummy);
 859
 
 
 
 
 
 
 
 
 
 
 
 860/**
 861 * i2c_new_secondary_device - Helper to get the instantiated secondary address
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 862 * and create the associated device
 863 * @client: Handle to the primary client
 864 * @name: Handle to specify which secondary address to get
 865 * @default_addr: Used as a fallback if no secondary address was specified
 866 * Context: can sleep
 867 *
 868 * I2C clients can be composed of multiple I2C slaves bound together in a single
 869 * component. The I2C client driver then binds to the master I2C slave and needs
 870 * to create I2C dummy clients to communicate with all the other slaves.
 871 *
 872 * This function creates and returns an I2C dummy client whose I2C address is
 873 * retrieved from the platform firmware based on the given slave name. If no
 874 * address is specified by the firmware default_addr is used.
 875 *
 876 * On DT-based platforms the address is retrieved from the "reg" property entry
 877 * cell whose "reg-names" value matches the slave name.
 878 *
 879 * This returns the new i2c client, which should be saved for later use with
 880 * i2c_unregister_device(); or NULL to indicate an error.
 881 */
 882struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 883						const char *name,
 884						u16 default_addr)
 885{
 886	struct device_node *np = client->dev.of_node;
 887	u32 addr = default_addr;
 888	int i;
 889
 890	if (np) {
 891		i = of_property_match_string(np, "reg-names", name);
 892		if (i >= 0)
 893			of_property_read_u32_index(np, "reg", i, &addr);
 894	}
 895
 896	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 897	return i2c_new_dummy(client->adapter, addr);
 898}
 899EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 900
 901/* ------------------------------------------------------------------------- */
 902
 903/* I2C bus adapters -- one roots each I2C or SMBUS segment */
 904
 905static void i2c_adapter_dev_release(struct device *dev)
 906{
 907	struct i2c_adapter *adap = to_i2c_adapter(dev);
 908	complete(&adap->dev_released);
 909}
 910
 911unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 912{
 913	unsigned int depth = 0;
 914
 915	while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 916		depth++;
 917
 918	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 919		  "adapter depth exceeds lockdep subclass limit\n");
 920
 921	return depth;
 922}
 923EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 924
 925/*
 926 * Let users instantiate I2C devices through sysfs. This can be used when
 927 * platform initialization code doesn't contain the proper data for
 928 * whatever reason. Also useful for drivers that do device detection and
 929 * detection fails, either because the device uses an unexpected address,
 930 * or this is a compatible device with different ID register values.
 931 *
 932 * Parameter checking may look overzealous, but we really don't want
 933 * the user to provide incorrect parameters.
 934 */
 935static ssize_t
 936i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 937		     const char *buf, size_t count)
 938{
 939	struct i2c_adapter *adap = to_i2c_adapter(dev);
 940	struct i2c_board_info info;
 941	struct i2c_client *client;
 942	char *blank, end;
 943	int res;
 944
 945	memset(&info, 0, sizeof(struct i2c_board_info));
 946
 947	blank = strchr(buf, ' ');
 948	if (!blank) {
 949		dev_err(dev, "%s: Missing parameters\n", "new_device");
 950		return -EINVAL;
 951	}
 952	if (blank - buf > I2C_NAME_SIZE - 1) {
 953		dev_err(dev, "%s: Invalid device name\n", "new_device");
 954		return -EINVAL;
 955	}
 956	memcpy(info.type, buf, blank - buf);
 957
 958	/* Parse remaining parameters, reject extra parameters */
 959	res = sscanf(++blank, "%hi%c", &info.addr, &end);
 960	if (res < 1) {
 961		dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 962		return -EINVAL;
 963	}
 964	if (res > 1  && end != '\n') {
 965		dev_err(dev, "%s: Extra parameters\n", "new_device");
 966		return -EINVAL;
 967	}
 968
 969	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 970		info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 971		info.flags |= I2C_CLIENT_TEN;
 972	}
 973
 974	if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 975		info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 976		info.flags |= I2C_CLIENT_SLAVE;
 977	}
 978
 979	client = i2c_new_device(adap, &info);
 980	if (!client)
 981		return -EINVAL;
 982
 983	/* Keep track of the added device */
 984	mutex_lock(&adap->userspace_clients_lock);
 985	list_add_tail(&client->detected, &adap->userspace_clients);
 986	mutex_unlock(&adap->userspace_clients_lock);
 987	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
 988		 info.type, info.addr);
 989
 990	return count;
 991}
 992static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
 993
 994/*
 995 * And of course let the users delete the devices they instantiated, if
 996 * they got it wrong. This interface can only be used to delete devices
 997 * instantiated by i2c_sysfs_new_device above. This guarantees that we
 998 * don't delete devices to which some kernel code still has references.
 999 *
1000 * Parameter checking may look overzealous, but we really don't want
1001 * the user to delete the wrong device.
1002 */
1003static ssize_t
1004i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1005			const char *buf, size_t count)
1006{
1007	struct i2c_adapter *adap = to_i2c_adapter(dev);
1008	struct i2c_client *client, *next;
1009	unsigned short addr;
1010	char end;
1011	int res;
1012
1013	/* Parse parameters, reject extra parameters */
1014	res = sscanf(buf, "%hi%c", &addr, &end);
1015	if (res < 1) {
1016		dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1017		return -EINVAL;
1018	}
1019	if (res > 1  && end != '\n') {
1020		dev_err(dev, "%s: Extra parameters\n", "delete_device");
1021		return -EINVAL;
1022	}
1023
1024	/* Make sure the device was added through sysfs */
1025	res = -ENOENT;
1026	mutex_lock_nested(&adap->userspace_clients_lock,
1027			  i2c_adapter_depth(adap));
1028	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1029				 detected) {
1030		if (i2c_encode_flags_to_addr(client) == addr) {
1031			dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1032				 "delete_device", client->name, client->addr);
1033
1034			list_del(&client->detected);
1035			i2c_unregister_device(client);
1036			res = count;
1037			break;
1038		}
1039	}
1040	mutex_unlock(&adap->userspace_clients_lock);
1041
1042	if (res < 0)
1043		dev_err(dev, "%s: Can't find device in list\n",
1044			"delete_device");
1045	return res;
1046}
1047static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1048				   i2c_sysfs_delete_device);
1049
1050static struct attribute *i2c_adapter_attrs[] = {
1051	&dev_attr_name.attr,
1052	&dev_attr_new_device.attr,
1053	&dev_attr_delete_device.attr,
1054	NULL
1055};
1056ATTRIBUTE_GROUPS(i2c_adapter);
1057
1058struct device_type i2c_adapter_type = {
1059	.groups		= i2c_adapter_groups,
1060	.release	= i2c_adapter_dev_release,
1061};
1062EXPORT_SYMBOL_GPL(i2c_adapter_type);
1063
1064/**
1065 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1066 * @dev: device, probably from some driver model iterator
1067 *
1068 * When traversing the driver model tree, perhaps using driver model
1069 * iterators like @device_for_each_child(), you can't assume very much
1070 * about the nodes you find.  Use this function to avoid oopses caused
1071 * by wrongly treating some non-I2C device as an i2c_adapter.
1072 */
1073struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1074{
1075	return (dev->type == &i2c_adapter_type)
1076			? to_i2c_adapter(dev)
1077			: NULL;
1078}
1079EXPORT_SYMBOL(i2c_verify_adapter);
1080
1081#ifdef CONFIG_I2C_COMPAT
1082static struct class_compat *i2c_adapter_compat_class;
1083#endif
1084
1085static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1086{
1087	struct i2c_devinfo	*devinfo;
1088
1089	down_read(&__i2c_board_lock);
1090	list_for_each_entry(devinfo, &__i2c_board_list, list) {
1091		if (devinfo->busnum == adapter->nr
1092				&& !i2c_new_device(adapter,
1093						&devinfo->board_info))
1094			dev_err(&adapter->dev,
1095				"Can't create device at 0x%02x\n",
1096				devinfo->board_info.addr);
1097	}
1098	up_read(&__i2c_board_lock);
1099}
1100
1101static int i2c_do_add_adapter(struct i2c_driver *driver,
1102			      struct i2c_adapter *adap)
1103{
1104	/* Detect supported devices on that bus, and instantiate them */
1105	i2c_detect(adap, driver);
1106
1107	/* Let legacy drivers scan this bus for matching devices */
1108	if (driver->attach_adapter) {
1109		dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1110			 driver->driver.name);
1111		dev_warn(&adap->dev,
1112			 "Please use another way to instantiate your i2c_client\n");
1113		/* We ignore the return code; if it fails, too bad */
1114		driver->attach_adapter(adap);
1115	}
1116	return 0;
1117}
1118
1119static int __process_new_adapter(struct device_driver *d, void *data)
1120{
1121	return i2c_do_add_adapter(to_i2c_driver(d), data);
1122}
1123
1124static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1125	.lock_bus =    i2c_adapter_lock_bus,
1126	.trylock_bus = i2c_adapter_trylock_bus,
1127	.unlock_bus =  i2c_adapter_unlock_bus,
1128};
1129
1130static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1131{
1132	struct irq_domain *domain = adap->host_notify_domain;
1133	irq_hw_number_t hwirq;
1134
1135	if (!domain)
1136		return;
1137
1138	for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1139		irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1140
1141	irq_domain_remove(domain);
1142	adap->host_notify_domain = NULL;
1143}
1144
1145static int i2c_host_notify_irq_map(struct irq_domain *h,
1146					  unsigned int virq,
1147					  irq_hw_number_t hw_irq_num)
1148{
1149	irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1150
1151	return 0;
1152}
1153
1154static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1155	.map = i2c_host_notify_irq_map,
1156};
1157
1158static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1159{
1160	struct irq_domain *domain;
1161
1162	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1163		return 0;
1164
1165	domain = irq_domain_create_linear(adap->dev.fwnode,
1166					  I2C_ADDR_7BITS_COUNT,
1167					  &i2c_host_notify_irq_ops, adap);
1168	if (!domain)
1169		return -ENOMEM;
1170
1171	adap->host_notify_domain = domain;
1172
1173	return 0;
1174}
1175
1176/**
1177 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1178 * I2C client.
1179 * @adap: the adapter
1180 * @addr: the I2C address of the notifying device
1181 * Context: can't sleep
1182 *
1183 * Helper function to be called from an I2C bus driver's interrupt
1184 * handler. It will schedule the Host Notify IRQ.
1185 */
1186int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1187{
1188	int irq;
1189
1190	if (!adap)
1191		return -EINVAL;
1192
1193	irq = irq_find_mapping(adap->host_notify_domain, addr);
1194	if (irq <= 0)
1195		return -ENXIO;
1196
1197	generic_handle_irq(irq);
1198
1199	return 0;
1200}
1201EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1202
1203static int i2c_register_adapter(struct i2c_adapter *adap)
1204{
1205	int res = -EINVAL;
1206
1207	/* Can't register until after driver model init */
1208	if (WARN_ON(!is_registered)) {
1209		res = -EAGAIN;
1210		goto out_list;
1211	}
1212
1213	/* Sanity checks */
1214	if (WARN(!adap->name[0], "i2c adapter has no name"))
1215		goto out_list;
1216
1217	if (!adap->algo) {
1218		pr_err("adapter '%s': no algo supplied!\n", adap->name);
1219		goto out_list;
1220	}
1221
1222	if (!adap->lock_ops)
1223		adap->lock_ops = &i2c_adapter_lock_ops;
1224
 
1225	rt_mutex_init(&adap->bus_lock);
1226	rt_mutex_init(&adap->mux_lock);
1227	mutex_init(&adap->userspace_clients_lock);
1228	INIT_LIST_HEAD(&adap->userspace_clients);
1229
1230	/* Set default timeout to 1 second if not already set */
1231	if (adap->timeout == 0)
1232		adap->timeout = HZ;
1233
1234	/* register soft irqs for Host Notify */
1235	res = i2c_setup_host_notify_irq_domain(adap);
1236	if (res) {
1237		pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1238		       adap->name, res);
1239		goto out_list;
1240	}
1241
1242	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1243	adap->dev.bus = &i2c_bus_type;
1244	adap->dev.type = &i2c_adapter_type;
1245	res = device_register(&adap->dev);
1246	if (res) {
1247		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1248		goto out_list;
1249	}
1250
1251	res = of_i2c_setup_smbus_alert(adap);
1252	if (res)
1253		goto out_reg;
1254
1255	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1256
1257	pm_runtime_no_callbacks(&adap->dev);
1258	pm_suspend_ignore_children(&adap->dev, true);
1259	pm_runtime_enable(&adap->dev);
1260
1261#ifdef CONFIG_I2C_COMPAT
1262	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1263				       adap->dev.parent);
1264	if (res)
1265		dev_warn(&adap->dev,
1266			 "Failed to create compatibility class link\n");
1267#endif
1268
1269	i2c_init_recovery(adap);
1270
1271	/* create pre-declared device nodes */
1272	of_i2c_register_devices(adap);
1273	i2c_acpi_register_devices(adap);
1274	i2c_acpi_install_space_handler(adap);
1275
1276	if (adap->nr < __i2c_first_dynamic_bus_num)
1277		i2c_scan_static_board_info(adap);
1278
1279	/* Notify drivers */
1280	mutex_lock(&core_lock);
1281	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1282	mutex_unlock(&core_lock);
1283
1284	return 0;
1285
1286out_reg:
1287	init_completion(&adap->dev_released);
1288	device_unregister(&adap->dev);
1289	wait_for_completion(&adap->dev_released);
1290out_list:
1291	mutex_lock(&core_lock);
1292	idr_remove(&i2c_adapter_idr, adap->nr);
1293	mutex_unlock(&core_lock);
1294	return res;
1295}
1296
1297/**
1298 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1299 * @adap: the adapter to register (with adap->nr initialized)
1300 * Context: can sleep
1301 *
1302 * See i2c_add_numbered_adapter() for details.
1303 */
1304static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1305{
1306	int id;
1307
1308	mutex_lock(&core_lock);
1309	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1310	mutex_unlock(&core_lock);
1311	if (WARN(id < 0, "couldn't get idr"))
1312		return id == -ENOSPC ? -EBUSY : id;
1313
1314	return i2c_register_adapter(adap);
1315}
1316
1317/**
1318 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1319 * @adapter: the adapter to add
1320 * Context: can sleep
1321 *
1322 * This routine is used to declare an I2C adapter when its bus number
1323 * doesn't matter or when its bus number is specified by an dt alias.
1324 * Examples of bases when the bus number doesn't matter: I2C adapters
1325 * dynamically added by USB links or PCI plugin cards.
1326 *
1327 * When this returns zero, a new bus number was allocated and stored
1328 * in adap->nr, and the specified adapter became available for clients.
1329 * Otherwise, a negative errno value is returned.
1330 */
1331int i2c_add_adapter(struct i2c_adapter *adapter)
1332{
1333	struct device *dev = &adapter->dev;
1334	int id;
1335
1336	if (dev->of_node) {
1337		id = of_alias_get_id(dev->of_node, "i2c");
1338		if (id >= 0) {
1339			adapter->nr = id;
1340			return __i2c_add_numbered_adapter(adapter);
1341		}
1342	}
1343
1344	mutex_lock(&core_lock);
1345	id = idr_alloc(&i2c_adapter_idr, adapter,
1346		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1347	mutex_unlock(&core_lock);
1348	if (WARN(id < 0, "couldn't get idr"))
1349		return id;
1350
1351	adapter->nr = id;
1352
1353	return i2c_register_adapter(adapter);
1354}
1355EXPORT_SYMBOL(i2c_add_adapter);
1356
1357/**
1358 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1359 * @adap: the adapter to register (with adap->nr initialized)
1360 * Context: can sleep
1361 *
1362 * This routine is used to declare an I2C adapter when its bus number
1363 * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1364 * or otherwise built in to the system's mainboard, and where i2c_board_info
1365 * is used to properly configure I2C devices.
1366 *
1367 * If the requested bus number is set to -1, then this function will behave
1368 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1369 *
1370 * If no devices have pre-been declared for this bus, then be sure to
1371 * register the adapter before any dynamically allocated ones.  Otherwise
1372 * the required bus ID may not be available.
1373 *
1374 * When this returns zero, the specified adapter became available for
1375 * clients using the bus number provided in adap->nr.  Also, the table
1376 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1377 * and the appropriate driver model device nodes are created.  Otherwise, a
1378 * negative errno value is returned.
1379 */
1380int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1381{
1382	if (adap->nr == -1) /* -1 means dynamically assign bus id */
1383		return i2c_add_adapter(adap);
1384
1385	return __i2c_add_numbered_adapter(adap);
1386}
1387EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1388
1389static void i2c_do_del_adapter(struct i2c_driver *driver,
1390			      struct i2c_adapter *adapter)
1391{
1392	struct i2c_client *client, *_n;
1393
1394	/* Remove the devices we created ourselves as the result of hardware
1395	 * probing (using a driver's detect method) */
1396	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1397		if (client->adapter == adapter) {
1398			dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1399				client->name, client->addr);
1400			list_del(&client->detected);
1401			i2c_unregister_device(client);
1402		}
1403	}
1404}
1405
1406static int __unregister_client(struct device *dev, void *dummy)
1407{
1408	struct i2c_client *client = i2c_verify_client(dev);
1409	if (client && strcmp(client->name, "dummy"))
1410		i2c_unregister_device(client);
1411	return 0;
1412}
1413
1414static int __unregister_dummy(struct device *dev, void *dummy)
1415{
1416	struct i2c_client *client = i2c_verify_client(dev);
1417	i2c_unregister_device(client);
1418	return 0;
1419}
1420
1421static int __process_removed_adapter(struct device_driver *d, void *data)
1422{
1423	i2c_do_del_adapter(to_i2c_driver(d), data);
1424	return 0;
1425}
1426
1427/**
1428 * i2c_del_adapter - unregister I2C adapter
1429 * @adap: the adapter being unregistered
1430 * Context: can sleep
1431 *
1432 * This unregisters an I2C adapter which was previously registered
1433 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1434 */
1435void i2c_del_adapter(struct i2c_adapter *adap)
1436{
1437	struct i2c_adapter *found;
1438	struct i2c_client *client, *next;
1439
1440	/* First make sure that this adapter was ever added */
1441	mutex_lock(&core_lock);
1442	found = idr_find(&i2c_adapter_idr, adap->nr);
1443	mutex_unlock(&core_lock);
1444	if (found != adap) {
1445		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1446		return;
1447	}
1448
1449	i2c_acpi_remove_space_handler(adap);
1450	/* Tell drivers about this removal */
1451	mutex_lock(&core_lock);
1452	bus_for_each_drv(&i2c_bus_type, NULL, adap,
1453			       __process_removed_adapter);
1454	mutex_unlock(&core_lock);
1455
1456	/* Remove devices instantiated from sysfs */
1457	mutex_lock_nested(&adap->userspace_clients_lock,
1458			  i2c_adapter_depth(adap));
1459	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1460				 detected) {
1461		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1462			client->addr);
1463		list_del(&client->detected);
1464		i2c_unregister_device(client);
1465	}
1466	mutex_unlock(&adap->userspace_clients_lock);
1467
1468	/* Detach any active clients. This can't fail, thus we do not
1469	 * check the returned value. This is a two-pass process, because
1470	 * we can't remove the dummy devices during the first pass: they
1471	 * could have been instantiated by real devices wishing to clean
1472	 * them up properly, so we give them a chance to do that first. */
1473	device_for_each_child(&adap->dev, NULL, __unregister_client);
1474	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1475
1476#ifdef CONFIG_I2C_COMPAT
1477	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1478				 adap->dev.parent);
1479#endif
1480
1481	/* device name is gone after device_unregister */
1482	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1483
1484	pm_runtime_disable(&adap->dev);
1485
1486	i2c_host_notify_irq_teardown(adap);
1487
1488	/* wait until all references to the device are gone
1489	 *
1490	 * FIXME: This is old code and should ideally be replaced by an
1491	 * alternative which results in decoupling the lifetime of the struct
1492	 * device from the i2c_adapter, like spi or netdev do. Any solution
1493	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1494	 */
1495	init_completion(&adap->dev_released);
1496	device_unregister(&adap->dev);
1497	wait_for_completion(&adap->dev_released);
1498
1499	/* free bus id */
1500	mutex_lock(&core_lock);
1501	idr_remove(&i2c_adapter_idr, adap->nr);
1502	mutex_unlock(&core_lock);
1503
1504	/* Clear the device structure in case this adapter is ever going to be
1505	   added again */
1506	memset(&adap->dev, 0, sizeof(adap->dev));
1507}
1508EXPORT_SYMBOL(i2c_del_adapter);
1509
1510/**
1511 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1512 * @dev: The device to scan for I2C timing properties
1513 * @t: the i2c_timings struct to be filled with values
1514 * @use_defaults: bool to use sane defaults derived from the I2C specification
1515 *		  when properties are not found, otherwise use 0
1516 *
1517 * Scan the device for the generic I2C properties describing timing parameters
1518 * for the signal and fill the given struct with the results. If a property was
1519 * not found and use_defaults was true, then maximum timings are assumed which
1520 * are derived from the I2C specification. If use_defaults is not used, the
1521 * results will be 0, so drivers can apply their own defaults later. The latter
1522 * is mainly intended for avoiding regressions of existing drivers which want
1523 * to switch to this function. New drivers almost always should use the defaults.
1524 */
1525
1526void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1527{
1528	int ret;
1529
1530	memset(t, 0, sizeof(*t));
1531
1532	ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1533	if (ret && use_defaults)
1534		t->bus_freq_hz = 100000;
1535
1536	ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1537	if (ret && use_defaults) {
1538		if (t->bus_freq_hz <= 100000)
1539			t->scl_rise_ns = 1000;
1540		else if (t->bus_freq_hz <= 400000)
1541			t->scl_rise_ns = 300;
1542		else
1543			t->scl_rise_ns = 120;
1544	}
1545
1546	ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1547	if (ret && use_defaults) {
1548		if (t->bus_freq_hz <= 400000)
1549			t->scl_fall_ns = 300;
1550		else
1551			t->scl_fall_ns = 120;
1552	}
1553
1554	device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1555
1556	ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1557	if (ret && use_defaults)
1558		t->sda_fall_ns = t->scl_fall_ns;
 
 
1559}
1560EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1561
1562/* ------------------------------------------------------------------------- */
1563
1564int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1565{
1566	int res;
1567
1568	mutex_lock(&core_lock);
1569	res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1570	mutex_unlock(&core_lock);
1571
1572	return res;
1573}
1574EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1575
1576static int __process_new_driver(struct device *dev, void *data)
1577{
1578	if (dev->type != &i2c_adapter_type)
1579		return 0;
1580	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1581}
1582
1583/*
1584 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1585 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1586 */
1587
1588int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1589{
1590	int res;
1591
1592	/* Can't register until after driver model init */
1593	if (WARN_ON(!is_registered))
1594		return -EAGAIN;
1595
1596	/* add the driver to the list of i2c drivers in the driver core */
1597	driver->driver.owner = owner;
1598	driver->driver.bus = &i2c_bus_type;
1599	INIT_LIST_HEAD(&driver->clients);
1600
1601	/* When registration returns, the driver core
1602	 * will have called probe() for all matching-but-unbound devices.
1603	 */
1604	res = driver_register(&driver->driver);
1605	if (res)
1606		return res;
1607
1608	pr_debug("driver [%s] registered\n", driver->driver.name);
1609
1610	/* Walk the adapters that are already present */
1611	i2c_for_each_dev(driver, __process_new_driver);
1612
1613	return 0;
1614}
1615EXPORT_SYMBOL(i2c_register_driver);
1616
1617static int __process_removed_driver(struct device *dev, void *data)
1618{
1619	if (dev->type == &i2c_adapter_type)
1620		i2c_do_del_adapter(data, to_i2c_adapter(dev));
1621	return 0;
1622}
1623
1624/**
1625 * i2c_del_driver - unregister I2C driver
1626 * @driver: the driver being unregistered
1627 * Context: can sleep
1628 */
1629void i2c_del_driver(struct i2c_driver *driver)
1630{
1631	i2c_for_each_dev(driver, __process_removed_driver);
1632
1633	driver_unregister(&driver->driver);
1634	pr_debug("driver [%s] unregistered\n", driver->driver.name);
1635}
1636EXPORT_SYMBOL(i2c_del_driver);
1637
1638/* ------------------------------------------------------------------------- */
1639
1640/**
1641 * i2c_use_client - increments the reference count of the i2c client structure
1642 * @client: the client being referenced
1643 *
1644 * Each live reference to a client should be refcounted. The driver model does
1645 * that automatically as part of driver binding, so that most drivers don't
1646 * need to do this explicitly: they hold a reference until they're unbound
1647 * from the device.
1648 *
1649 * A pointer to the client with the incremented reference counter is returned.
1650 */
1651struct i2c_client *i2c_use_client(struct i2c_client *client)
1652{
1653	if (client && get_device(&client->dev))
1654		return client;
1655	return NULL;
1656}
1657EXPORT_SYMBOL(i2c_use_client);
1658
1659/**
1660 * i2c_release_client - release a use of the i2c client structure
1661 * @client: the client being no longer referenced
1662 *
1663 * Must be called when a user of a client is finished with it.
1664 */
1665void i2c_release_client(struct i2c_client *client)
1666{
1667	if (client)
1668		put_device(&client->dev);
1669}
1670EXPORT_SYMBOL(i2c_release_client);
1671
1672struct i2c_cmd_arg {
1673	unsigned	cmd;
1674	void		*arg;
1675};
1676
1677static int i2c_cmd(struct device *dev, void *_arg)
1678{
1679	struct i2c_client	*client = i2c_verify_client(dev);
1680	struct i2c_cmd_arg	*arg = _arg;
1681	struct i2c_driver	*driver;
1682
1683	if (!client || !client->dev.driver)
1684		return 0;
1685
1686	driver = to_i2c_driver(client->dev.driver);
1687	if (driver->command)
1688		driver->command(client, arg->cmd, arg->arg);
1689	return 0;
1690}
1691
1692void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1693{
1694	struct i2c_cmd_arg	cmd_arg;
1695
1696	cmd_arg.cmd = cmd;
1697	cmd_arg.arg = arg;
1698	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1699}
1700EXPORT_SYMBOL(i2c_clients_command);
1701
1702static int __init i2c_init(void)
1703{
1704	int retval;
1705
1706	retval = of_alias_get_highest_id("i2c");
1707
1708	down_write(&__i2c_board_lock);
1709	if (retval >= __i2c_first_dynamic_bus_num)
1710		__i2c_first_dynamic_bus_num = retval + 1;
1711	up_write(&__i2c_board_lock);
1712
1713	retval = bus_register(&i2c_bus_type);
1714	if (retval)
1715		return retval;
1716
1717	is_registered = true;
1718
1719#ifdef CONFIG_I2C_COMPAT
1720	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1721	if (!i2c_adapter_compat_class) {
1722		retval = -ENOMEM;
1723		goto bus_err;
1724	}
1725#endif
1726	retval = i2c_add_driver(&dummy_driver);
1727	if (retval)
1728		goto class_err;
1729
1730	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1731		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1732	if (IS_ENABLED(CONFIG_ACPI))
1733		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1734
1735	return 0;
1736
1737class_err:
1738#ifdef CONFIG_I2C_COMPAT
1739	class_compat_unregister(i2c_adapter_compat_class);
1740bus_err:
1741#endif
1742	is_registered = false;
1743	bus_unregister(&i2c_bus_type);
1744	return retval;
1745}
1746
1747static void __exit i2c_exit(void)
1748{
1749	if (IS_ENABLED(CONFIG_ACPI))
1750		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1751	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1752		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1753	i2c_del_driver(&dummy_driver);
1754#ifdef CONFIG_I2C_COMPAT
1755	class_compat_unregister(i2c_adapter_compat_class);
1756#endif
1757	bus_unregister(&i2c_bus_type);
1758	tracepoint_synchronize_unregister();
1759}
1760
1761/* We must initialize early, because some subsystems register i2c drivers
1762 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1763 */
1764postcore_initcall(i2c_init);
1765module_exit(i2c_exit);
1766
1767/* ----------------------------------------------------
1768 * the functional interface to the i2c busses.
1769 * ----------------------------------------------------
1770 */
1771
1772/* Check if val is exceeding the quirk IFF quirk is non 0 */
1773#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1774
1775static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1776{
1777	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1778			    err_msg, msg->addr, msg->len,
1779			    msg->flags & I2C_M_RD ? "read" : "write");
1780	return -EOPNOTSUPP;
1781}
1782
1783static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1784{
1785	const struct i2c_adapter_quirks *q = adap->quirks;
1786	int max_num = q->max_num_msgs, i;
1787	bool do_len_check = true;
1788
1789	if (q->flags & I2C_AQ_COMB) {
1790		max_num = 2;
1791
1792		/* special checks for combined messages */
1793		if (num == 2) {
1794			if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1795				return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1796
1797			if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1798				return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1799
1800			if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1801				return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1802
1803			if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1804				return i2c_quirk_error(adap, &msgs[0], "msg too long");
1805
1806			if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1807				return i2c_quirk_error(adap, &msgs[1], "msg too long");
1808
1809			do_len_check = false;
1810		}
1811	}
1812
1813	if (i2c_quirk_exceeded(num, max_num))
1814		return i2c_quirk_error(adap, &msgs[0], "too many messages");
1815
1816	for (i = 0; i < num; i++) {
1817		u16 len = msgs[i].len;
1818
1819		if (msgs[i].flags & I2C_M_RD) {
1820			if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1821				return i2c_quirk_error(adap, &msgs[i], "msg too long");
 
 
 
1822		} else {
1823			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1824				return i2c_quirk_error(adap, &msgs[i], "msg too long");
 
 
 
1825		}
1826	}
1827
1828	return 0;
1829}
1830
1831/**
1832 * __i2c_transfer - unlocked flavor of i2c_transfer
1833 * @adap: Handle to I2C bus
1834 * @msgs: One or more messages to execute before STOP is issued to
1835 *	terminate the operation; each message begins with a START.
1836 * @num: Number of messages to be executed.
1837 *
1838 * Returns negative errno, else the number of messages executed.
1839 *
1840 * Adapter lock must be held when calling this function. No debug logging
1841 * takes place. adap->algo->master_xfer existence isn't checked.
1842 */
1843int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1844{
1845	unsigned long orig_jiffies;
1846	int ret, try;
1847
1848	if (WARN_ON(!msgs || num < 1))
1849		return -EINVAL;
1850
 
 
 
 
1851	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1852		return -EOPNOTSUPP;
1853
1854	/*
1855	 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1856	 * enabled.  This is an efficient way of keeping the for-loop from
1857	 * being executed when not needed.
1858	 */
1859	if (static_branch_unlikely(&i2c_trace_msg_key)) {
1860		int i;
1861		for (i = 0; i < num; i++)
1862			if (msgs[i].flags & I2C_M_RD)
1863				trace_i2c_read(adap, &msgs[i], i);
1864			else
1865				trace_i2c_write(adap, &msgs[i], i);
1866	}
1867
1868	/* Retry automatically on arbitration loss */
1869	orig_jiffies = jiffies;
1870	for (ret = 0, try = 0; try <= adap->retries; try++) {
1871		ret = adap->algo->master_xfer(adap, msgs, num);
 
 
 
 
1872		if (ret != -EAGAIN)
1873			break;
1874		if (time_after(jiffies, orig_jiffies + adap->timeout))
1875			break;
1876	}
1877
1878	if (static_branch_unlikely(&i2c_trace_msg_key)) {
1879		int i;
1880		for (i = 0; i < ret; i++)
1881			if (msgs[i].flags & I2C_M_RD)
1882				trace_i2c_reply(adap, &msgs[i], i);
1883		trace_i2c_result(adap, num, ret);
1884	}
1885
1886	return ret;
1887}
1888EXPORT_SYMBOL(__i2c_transfer);
1889
1890/**
1891 * i2c_transfer - execute a single or combined I2C message
1892 * @adap: Handle to I2C bus
1893 * @msgs: One or more messages to execute before STOP is issued to
1894 *	terminate the operation; each message begins with a START.
1895 * @num: Number of messages to be executed.
1896 *
1897 * Returns negative errno, else the number of messages executed.
1898 *
1899 * Note that there is no requirement that each message be sent to
1900 * the same slave address, although that is the most common model.
1901 */
1902int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1903{
1904	int ret;
1905
 
 
 
 
 
1906	/* REVISIT the fault reporting model here is weak:
1907	 *
1908	 *  - When we get an error after receiving N bytes from a slave,
1909	 *    there is no way to report "N".
1910	 *
1911	 *  - When we get a NAK after transmitting N bytes to a slave,
1912	 *    there is no way to report "N" ... or to let the master
1913	 *    continue executing the rest of this combined message, if
1914	 *    that's the appropriate response.
1915	 *
1916	 *  - When for example "num" is two and we successfully complete
1917	 *    the first message but get an error part way through the
1918	 *    second, it's unclear whether that should be reported as
1919	 *    one (discarding status on the second message) or errno
1920	 *    (discarding status on the first one).
1921	 */
 
 
 
1922
1923	if (adap->algo->master_xfer) {
1924#ifdef DEBUG
1925		for (ret = 0; ret < num; ret++) {
1926			dev_dbg(&adap->dev,
1927				"master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1928				ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1929				msgs[ret].addr, msgs[ret].len,
1930				(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1931		}
1932#endif
1933
1934		if (in_atomic() || irqs_disabled()) {
1935			ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1936			if (!ret)
1937				/* I2C activity is ongoing. */
1938				return -EAGAIN;
1939		} else {
1940			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1941		}
1942
1943		ret = __i2c_transfer(adap, msgs, num);
1944		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1945
1946		return ret;
1947	} else {
1948		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1949		return -EOPNOTSUPP;
1950	}
1951}
1952EXPORT_SYMBOL(i2c_transfer);
1953
1954/**
1955 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1956 *			       to/from a buffer
1957 * @client: Handle to slave device
1958 * @buf: Where the data is stored
1959 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1960 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1961 *
1962 * Returns negative errno, or else the number of bytes transferred.
1963 */
1964int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1965			      int count, u16 flags)
1966{
1967	int ret;
1968	struct i2c_msg msg = {
1969		.addr = client->addr,
1970		.flags = flags | (client->flags & I2C_M_TEN),
1971		.len = count,
1972		.buf = buf,
1973	};
1974
1975	ret = i2c_transfer(client->adapter, &msg, 1);
1976
1977	/*
1978	 * If everything went ok (i.e. 1 msg transferred), return #bytes
1979	 * transferred, else error code.
1980	 */
1981	return (ret == 1) ? count : ret;
1982}
1983EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1984
1985/**
1986 * i2c_get_device_id - get manufacturer, part id and die revision of a device
1987 * @client: The device to query
1988 * @id: The queried information
1989 *
1990 * Returns negative errno on error, zero on success.
1991 */
1992int i2c_get_device_id(const struct i2c_client *client,
1993		      struct i2c_device_identity *id)
1994{
1995	struct i2c_adapter *adap = client->adapter;
1996	union i2c_smbus_data raw_id;
1997	int ret;
1998
1999	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2000		return -EOPNOTSUPP;
2001
2002	raw_id.block[0] = 3;
2003	ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2004			     I2C_SMBUS_READ, client->addr << 1,
2005			     I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2006	if (ret)
2007		return ret;
2008
2009	id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2010	id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2011	id->die_revision = raw_id.block[3] & 0x7;
2012	return 0;
2013}
2014EXPORT_SYMBOL_GPL(i2c_get_device_id);
2015
2016/* ----------------------------------------------------
2017 * the i2c address scanning function
2018 * Will not work for 10-bit addresses!
2019 * ----------------------------------------------------
2020 */
2021
2022/*
2023 * Legacy default probe function, mostly relevant for SMBus. The default
2024 * probe method is a quick write, but it is known to corrupt the 24RF08
2025 * EEPROMs due to a state machine bug, and could also irreversibly
2026 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2027 * we use a short byte read instead. Also, some bus drivers don't implement
2028 * quick write, so we fallback to a byte read in that case too.
2029 * On x86, there is another special case for FSC hardware monitoring chips,
2030 * which want regular byte reads (address 0x73.) Fortunately, these are the
2031 * only known chips using this I2C address on PC hardware.
2032 * Returns 1 if probe succeeded, 0 if not.
2033 */
2034static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2035{
2036	int err;
2037	union i2c_smbus_data dummy;
2038
2039#ifdef CONFIG_X86
2040	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2041	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2042		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2043				     I2C_SMBUS_BYTE_DATA, &dummy);
2044	else
2045#endif
2046	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2047	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2048		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2049				     I2C_SMBUS_QUICK, NULL);
2050	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2051		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2052				     I2C_SMBUS_BYTE, &dummy);
2053	else {
2054		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2055			 addr);
2056		err = -EOPNOTSUPP;
2057	}
2058
2059	return err >= 0;
2060}
2061
2062static int i2c_detect_address(struct i2c_client *temp_client,
2063			      struct i2c_driver *driver)
2064{
2065	struct i2c_board_info info;
2066	struct i2c_adapter *adapter = temp_client->adapter;
2067	int addr = temp_client->addr;
2068	int err;
2069
2070	/* Make sure the address is valid */
2071	err = i2c_check_7bit_addr_validity_strict(addr);
2072	if (err) {
2073		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2074			 addr);
2075		return err;
2076	}
2077
2078	/* Skip if already in use (7 bit, no need to encode flags) */
2079	if (i2c_check_addr_busy(adapter, addr))
2080		return 0;
2081
2082	/* Make sure there is something at this address */
2083	if (!i2c_default_probe(adapter, addr))
2084		return 0;
2085
2086	/* Finally call the custom detection function */
2087	memset(&info, 0, sizeof(struct i2c_board_info));
2088	info.addr = addr;
2089	err = driver->detect(temp_client, &info);
2090	if (err) {
2091		/* -ENODEV is returned if the detection fails. We catch it
2092		   here as this isn't an error. */
2093		return err == -ENODEV ? 0 : err;
2094	}
2095
2096	/* Consistency check */
2097	if (info.type[0] == '\0') {
2098		dev_err(&adapter->dev,
2099			"%s detection function provided no name for 0x%x\n",
2100			driver->driver.name, addr);
2101	} else {
2102		struct i2c_client *client;
2103
2104		/* Detection succeeded, instantiate the device */
2105		if (adapter->class & I2C_CLASS_DEPRECATED)
2106			dev_warn(&adapter->dev,
2107				"This adapter will soon drop class based instantiation of devices. "
2108				"Please make sure client 0x%02x gets instantiated by other means. "
2109				"Check 'Documentation/i2c/instantiating-devices' for details.\n",
2110				info.addr);
2111
2112		dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2113			info.type, info.addr);
2114		client = i2c_new_device(adapter, &info);
2115		if (client)
2116			list_add_tail(&client->detected, &driver->clients);
2117		else
2118			dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2119				info.type, info.addr);
2120	}
2121	return 0;
2122}
2123
2124static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2125{
2126	const unsigned short *address_list;
2127	struct i2c_client *temp_client;
2128	int i, err = 0;
2129	int adap_id = i2c_adapter_id(adapter);
2130
2131	address_list = driver->address_list;
2132	if (!driver->detect || !address_list)
2133		return 0;
2134
2135	/* Warn that the adapter lost class based instantiation */
2136	if (adapter->class == I2C_CLASS_DEPRECATED) {
2137		dev_dbg(&adapter->dev,
2138			"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2139			"If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2140			driver->driver.name);
2141		return 0;
2142	}
2143
2144	/* Stop here if the classes do not match */
2145	if (!(adapter->class & driver->class))
2146		return 0;
2147
2148	/* Set up a temporary client to help detect callback */
2149	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2150	if (!temp_client)
2151		return -ENOMEM;
2152	temp_client->adapter = adapter;
2153
2154	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2155		dev_dbg(&adapter->dev,
2156			"found normal entry for adapter %d, addr 0x%02x\n",
2157			adap_id, address_list[i]);
2158		temp_client->addr = address_list[i];
2159		err = i2c_detect_address(temp_client, driver);
2160		if (unlikely(err))
2161			break;
2162	}
2163
2164	kfree(temp_client);
2165	return err;
2166}
2167
2168int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2169{
2170	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2171			      I2C_SMBUS_QUICK, NULL) >= 0;
2172}
2173EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2174
2175struct i2c_client *
2176i2c_new_probed_device(struct i2c_adapter *adap,
2177		      struct i2c_board_info *info,
2178		      unsigned short const *addr_list,
2179		      int (*probe)(struct i2c_adapter *, unsigned short addr))
2180{
2181	int i;
2182
2183	if (!probe)
2184		probe = i2c_default_probe;
2185
2186	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2187		/* Check address validity */
2188		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2189			dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2190				 addr_list[i]);
2191			continue;
2192		}
2193
2194		/* Check address availability (7 bit, no need to encode flags) */
2195		if (i2c_check_addr_busy(adap, addr_list[i])) {
2196			dev_dbg(&adap->dev,
2197				"Address 0x%02x already in use, not probing\n",
2198				addr_list[i]);
2199			continue;
2200		}
2201
2202		/* Test address responsiveness */
2203		if (probe(adap, addr_list[i]))
2204			break;
2205	}
2206
2207	if (addr_list[i] == I2C_CLIENT_END) {
2208		dev_dbg(&adap->dev, "Probing failed, no device found\n");
2209		return NULL;
2210	}
2211
2212	info->addr = addr_list[i];
2213	return i2c_new_device(adap, info);
2214}
2215EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2216
2217struct i2c_adapter *i2c_get_adapter(int nr)
2218{
2219	struct i2c_adapter *adapter;
2220
2221	mutex_lock(&core_lock);
2222	adapter = idr_find(&i2c_adapter_idr, nr);
2223	if (!adapter)
2224		goto exit;
2225
2226	if (try_module_get(adapter->owner))
2227		get_device(&adapter->dev);
2228	else
2229		adapter = NULL;
2230
2231 exit:
2232	mutex_unlock(&core_lock);
2233	return adapter;
2234}
2235EXPORT_SYMBOL(i2c_get_adapter);
2236
2237void i2c_put_adapter(struct i2c_adapter *adap)
2238{
2239	if (!adap)
2240		return;
2241
2242	put_device(&adap->dev);
2243	module_put(adap->owner);
2244}
2245EXPORT_SYMBOL(i2c_put_adapter);
2246
2247/**
2248 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2249 * @msg: the message to be checked
2250 * @threshold: the minimum number of bytes for which using DMA makes sense
 
2251 *
2252 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2253 *	   Or a valid pointer to be used with DMA. After use, release it by
2254 *	   calling i2c_release_dma_safe_msg_buf().
2255 *
2256 * This function must only be called from process context!
2257 */
2258u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2259{
2260	if (msg->len < threshold)
 
 
 
 
2261		return NULL;
2262
2263	if (msg->flags & I2C_M_DMA_SAFE)
2264		return msg->buf;
2265
2266	pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2267		 msg->addr, msg->len);
2268
2269	if (msg->flags & I2C_M_RD)
2270		return kzalloc(msg->len, GFP_KERNEL);
2271	else
2272		return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2273}
2274EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2275
2276/**
2277 * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2278 * @msg: the message to be synced with
2279 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
 
 
2280 */
2281void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
2282{
2283	if (!buf || buf == msg->buf)
2284		return;
2285
2286	if (msg->flags & I2C_M_RD)
2287		memcpy(msg->buf, buf, msg->len);
2288
2289	kfree(buf);
2290}
2291EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
2292
2293MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2294MODULE_DESCRIPTION("I2C-Bus main module");
2295MODULE_LICENSE("GPL");