i2c-core-base.c 63.0 KB
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/*
 * Linux I2C core
 *
 * Copyright (C) 1995-99 Simon G. Vogl
 *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
 *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
 *   Michael Lawnick <michael.lawnick.ext@nsn.com>
 *
 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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 */
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#define pr_fmt(fmt) "i2c-core: " fmt

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#include <dt-bindings/i2c/i2c.h>
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#include <linux/acpi.h>
#include <linux/clk/clk-conf.h>
#include <linux/completion.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/gpio/consumer.h>
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#include <linux/i2c.h>
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#include <linux/i2c-smbus.h>
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#include <linux/idr.h>
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#include <linux/init.h>
#include <linux/irqflags.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of_device.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/pm_domain.h>
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#include <linux/pm_runtime.h>
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#include <linux/pm_wakeirq.h>
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#include <linux/property.h>
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#include <linux/rwsem.h>
#include <linux/slab.h>
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#include "i2c-core.h"

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#define CREATE_TRACE_POINTS
#include <trace/events/i2c.h>
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#define I2C_ADDR_OFFSET_TEN_BIT	0xa000
#define I2C_ADDR_OFFSET_SLAVE	0x1000

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#define I2C_ADDR_7BITS_MAX	0x77
#define I2C_ADDR_7BITS_COUNT	(I2C_ADDR_7BITS_MAX + 1)

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#define I2C_ADDR_DEVICE_ID	0x7c

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/*
 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
 * deletion of detected devices, and attach_adapter calls are serialized
 */
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static DEFINE_MUTEX(core_lock);
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static DEFINE_IDR(i2c_adapter_idr);

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static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
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static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
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static bool is_registered;
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int i2c_transfer_trace_reg(void)
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{
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	static_branch_inc(&i2c_trace_msg_key);
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	return 0;
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}

void i2c_transfer_trace_unreg(void)
{
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	static_branch_dec(&i2c_trace_msg_key);
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}

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const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
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						const struct i2c_client *client)
{
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	if (!(id && client))
		return NULL;

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	while (id->name[0]) {
		if (strcmp(client->name, id->name) == 0)
			return id;
		id++;
	}
	return NULL;
}
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EXPORT_SYMBOL_GPL(i2c_match_id);
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static int i2c_device_match(struct device *dev, struct device_driver *drv)
{
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	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;

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	/* Attempt an OF style match */
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	if (i2c_of_match_device(drv->of_match_table, client))
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		return 1;

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

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	driver = to_i2c_driver(drv);
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	/* Finally an I2C match */
	if (i2c_match_id(driver->id_table, client))
		return 1;
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	return 0;
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}

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static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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	struct i2c_client *client = to_i2c_client(dev);
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	int rc;

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	rc = of_device_uevent_modalias(dev, env);
	if (rc != -ENODEV)
		return rc;

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	rc = acpi_device_uevent_modalias(dev, env);
	if (rc != -ENODEV)
		return rc;
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	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
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}

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/* i2c bus recovery routines */
static int get_scl_gpio_value(struct i2c_adapter *adap)
{
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	return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
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}

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

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

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static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
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{
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	gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
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}

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static int i2c_generic_bus_free(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
	int ret = -EOPNOTSUPP;

	if (bri->get_bus_free)
		ret = bri->get_bus_free(adap);
	else if (bri->get_sda)
		ret = bri->get_sda(adap);

	if (ret < 0)
		return ret;

	return ret ? 0 : -EBUSY;
}

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

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int i2c_generic_scl_recovery(struct i2c_adapter *adap)
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{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
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	int i = 0, scl = 1, ret;
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	if (bri->prepare_recovery)
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		bri->prepare_recovery(adap);
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	/*
	 * If we can set SDA, we will always create a STOP to ensure additional
	 * pulses will do no harm. This is achieved by letting SDA follow SCL
	 * half a cycle later. Check the 'incomplete_write_byte' fault injector
	 * for details.
	 */
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	bri->set_scl(adap, scl);
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	ndelay(RECOVERY_NDELAY / 2);
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	if (bri->set_sda)
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		bri->set_sda(adap, scl);
	ndelay(RECOVERY_NDELAY / 2);
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	/*
	 * By this time SCL is high, as we need to give 9 falling-rising edges
	 */
	while (i++ < RECOVERY_CLK_CNT * 2) {
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		if (scl) {
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			/* SCL shouldn't be low here */
			if (!bri->get_scl(adap)) {
				dev_err(&adap->dev,
					"SCL is stuck low, exit recovery\n");
				ret = -EBUSY;
				break;
			}
		}

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		scl = !scl;
		bri->set_scl(adap, scl);
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		/* Creating STOP again, see above */
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		ndelay(RECOVERY_NDELAY / 2);
		if (bri->set_sda)
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			bri->set_sda(adap, scl);
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		ndelay(RECOVERY_NDELAY / 2);
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		if (scl) {
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			ret = i2c_generic_bus_free(adap);
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			if (ret == 0)
				break;
		}
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	}

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	/* If we can't check bus status, assume recovery worked */
	if (ret == -EOPNOTSUPP)
		ret = 0;

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	if (bri->unprepare_recovery)
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		bri->unprepare_recovery(adap);
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	return ret;
}
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EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
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int i2c_recover_bus(struct i2c_adapter *adap)
{
	if (!adap->bus_recovery_info)
		return -EOPNOTSUPP;

	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
	return adap->bus_recovery_info->recover_bus(adap);
}
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EXPORT_SYMBOL_GPL(i2c_recover_bus);
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static void i2c_init_recovery(struct i2c_adapter *adap)
{
	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
	char *err_str;

	if (!bri)
		return;

	if (!bri->recover_bus) {
		err_str = "no recover_bus() found";
		goto err;
	}

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	if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
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		bri->get_scl = get_scl_gpio_value;
		bri->set_scl = set_scl_gpio_value;
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		if (bri->sda_gpiod) {
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			bri->get_sda = get_sda_gpio_value;
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			/* FIXME: add proper flag instead of '0' once available */
			if (gpiod_get_direction(bri->sda_gpiod) == 0)
				bri->set_sda = set_sda_gpio_value;
		}
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		return;
	}

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	if (bri->recover_bus == i2c_generic_scl_recovery) {
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		/* Generic SCL recovery */
		if (!bri->set_scl || !bri->get_scl) {
			err_str = "no {get|set}_scl() found";
			goto err;
		}
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		if (!bri->set_sda && !bri->get_sda) {
			err_str = "either get_sda() or set_sda() needed";
			goto err;
		}
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	}

	return;
 err:
	dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
	adap->bus_recovery_info = NULL;
}

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static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
{
	struct i2c_adapter *adap = client->adapter;
	unsigned int irq;

	if (!adap->host_notify_domain)
		return -ENXIO;

	if (client->flags & I2C_CLIENT_TEN)
		return -EINVAL;

	irq = irq_find_mapping(adap->host_notify_domain, client->addr);
	if (!irq)
		irq = irq_create_mapping(adap->host_notify_domain,
					 client->addr);

	return irq > 0 ? irq : -ENXIO;
}

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static int i2c_device_probe(struct device *dev)
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{
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	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_driver	*driver;
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	int status;
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	if (!client)
		return 0;

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	driver = to_i2c_driver(dev->driver);

	if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
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		int irq = -ENOENT;

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		if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
			dev_dbg(dev, "Using Host Notify IRQ\n");
			irq = i2c_smbus_host_notify_to_irq(client);
		} else if (dev->of_node) {
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			irq = of_irq_get_byname(dev->of_node, "irq");
			if (irq == -EINVAL || irq == -ENODATA)
				irq = of_irq_get(dev->of_node, 0);
		} else if (ACPI_COMPANION(dev)) {
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			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
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		}
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		if (irq == -EPROBE_DEFER)
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			return irq;
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		if (irq < 0)
			irq = 0;
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		client->irq = irq;
	}

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	/*
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	 * An I2C ID table is not mandatory, if and only if, a suitable OF
	 * or ACPI ID table is supplied for the probing device.
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	 */
	if (!driver->id_table &&
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	    !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
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	    !i2c_of_match_device(dev->driver->of_match_table, client))
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		return -ENODEV;
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	if (client->flags & I2C_CLIENT_WAKE) {
		int wakeirq = -ENOENT;

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

		device_init_wakeup(&client->dev, true);

		if (wakeirq > 0 && wakeirq != client->irq)
			status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
		else if (client->irq > 0)
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			status = dev_pm_set_wake_irq(dev, client->irq);
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		else
			status = 0;

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

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	dev_dbg(dev, "probe\n");
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	status = of_clk_set_defaults(dev->of_node, false);
	if (status < 0)
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		goto err_clear_wakeup_irq;
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	status = dev_pm_domain_attach(&client->dev, true);
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	if (status)
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		goto err_clear_wakeup_irq;

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	/*
	 * When there are no more users of probe(),
	 * rename probe_new to probe.
	 */
	if (driver->probe_new)
		status = driver->probe_new(client);
	else if (driver->probe)
		status = driver->probe(client,
				       i2c_match_id(driver->id_table, client));
	else
		status = -EINVAL;

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	if (status)
		goto err_detach_pm_domain;
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	return 0;

err_detach_pm_domain:
	dev_pm_domain_detach(&client->dev, true);
err_clear_wakeup_irq:
	dev_pm_clear_wake_irq(&client->dev);
	device_init_wakeup(&client->dev, false);
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	return status;
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}
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static int i2c_device_remove(struct device *dev)
{
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	struct i2c_client	*client = i2c_verify_client(dev);
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	struct i2c_driver	*driver;
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	int status = 0;
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	if (!client || !dev->driver)
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		return 0;

	driver = to_i2c_driver(dev->driver);
	if (driver->remove) {
		dev_dbg(dev, "remove\n");
		status = driver->remove(client);
	}
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	dev_pm_domain_detach(&client->dev, true);
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	dev_pm_clear_wake_irq(&client->dev);
	device_init_wakeup(&client->dev, false);

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	return status;
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}

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static void i2c_device_shutdown(struct device *dev)
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{
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	struct i2c_client *client = i2c_verify_client(dev);
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	struct i2c_driver *driver;

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	if (!client || !dev->driver)
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		return;
	driver = to_i2c_driver(dev->driver);
	if (driver->shutdown)
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		driver->shutdown(client);
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}

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static void i2c_client_dev_release(struct device *dev)
{
	kfree(to_i2c_client(dev));
}

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static ssize_t
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show_name(struct device *dev, struct device_attribute *attr, char *buf)
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{
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	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
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}
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static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
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static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
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{
	struct i2c_client *client = to_i2c_client(dev);
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	int len;

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

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

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	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
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}
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static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);

static struct attribute *i2c_dev_attrs[] = {
	&dev_attr_name.attr,
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	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
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	&dev_attr_modalias.attr,
	NULL
};
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ATTRIBUTE_GROUPS(i2c_dev);
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struct bus_type i2c_bus_type = {
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	.name		= "i2c",
	.match		= i2c_device_match,
	.probe		= i2c_device_probe,
	.remove		= i2c_device_remove,
	.shutdown	= i2c_device_shutdown,
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};
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EXPORT_SYMBOL_GPL(i2c_bus_type);
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struct device_type i2c_client_type = {
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	.groups		= i2c_dev_groups,
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	.uevent		= i2c_device_uevent,
	.release	= i2c_client_dev_release,
};
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EXPORT_SYMBOL_GPL(i2c_client_type);
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/**
 * i2c_verify_client - return parameter as i2c_client, or NULL
 * @dev: device, probably from some driver model iterator
 *
 * When traversing the driver model tree, perhaps using driver model
 * iterators like @device_for_each_child(), you can't assume very much
 * about the nodes you find.  Use this function to avoid oopses caused
 * by wrongly treating some non-I2C device as an i2c_client.
 */
struct i2c_client *i2c_verify_client(struct device *dev)
{
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	return (dev->type == &i2c_client_type)
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			? to_i2c_client(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);


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/* Return a unique address which takes the flags of the client into account */
static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
{
	unsigned short addr = client->addr;

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

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

	return addr;
}

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/* This is a permissive address validity check, I2C address map constraints
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 * are purposely not enforced, except for the general call address. */
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static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
543
{
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	if (flags & I2C_CLIENT_TEN) {
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		/* 10-bit address, all values are valid */
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		if (addr > 0x3ff)
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			return -EINVAL;
	} else {
		/* 7-bit address, reject the general call address */
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		if (addr == 0x00 || addr > 0x7f)
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			return -EINVAL;
	}
	return 0;
}

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

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static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	int			addr = *(int *)addrp;

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	if (client && i2c_encode_flags_to_addr(client) == addr)
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		return -EBUSY;
	return 0;
}

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/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
590
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
591 592 593 594 595
	int result;

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

596 597
	if (!result && parent)
		result = i2c_check_mux_parents(parent, addr);
598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615

	return result;
}

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

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

	return result;
}

616 617
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
618
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
619 620
	int result = 0;

621 622
	if (parent)
		result = i2c_check_mux_parents(parent, addr);
623 624 625 626 627 628

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

	return result;
629 630
}

631
/**
632
 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
633
 * @adapter: Target I2C bus segment
634 635
 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 *	locks only this branch in the adapter tree
636
 */
637 638
static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
				 unsigned int flags)
639
{
640
	rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
641 642 643
}

/**
644
 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
645
 * @adapter: Target I2C bus segment
646 647
 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	trylocks only this branch in the adapter tree
648
 */
649 650
static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
651
{
652
	return rt_mutex_trylock(&adapter->bus_lock);
653 654 655
}

/**
656
 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
657
 * @adapter: Target I2C bus segment
658 659
 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	unlocks only this branch in the adapter tree
660
 */
661 662
static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
663
{
664
	rt_mutex_unlock(&adapter->bus_lock);
665 666
}

667
static void i2c_dev_set_name(struct i2c_adapter *adap,
668 669
			     struct i2c_client *client,
			     struct i2c_board_info const *info)
670 671 672
{
	struct acpi_device *adev = ACPI_COMPANION(&client->dev);

673 674 675 676 677
	if (info && info->dev_name) {
		dev_set_name(&client->dev, "i2c-%s", info->dev_name);
		return;
	}

678 679 680 681 682 683
	if (adev) {
		dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
		return;
	}

	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
684
		     i2c_encode_flags_to_addr(client));
685 686
}

687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712
static int i2c_dev_irq_from_resources(const struct resource *resources,
				      unsigned int num_resources)
{
	struct irq_data *irqd;
	int i;

	for (i = 0; i < num_resources; i++) {
		const struct resource *r = &resources[i];

		if (resource_type(r) != IORESOURCE_IRQ)
			continue;

		if (r->flags & IORESOURCE_BITS) {
			irqd = irq_get_irq_data(r->start);
			if (!irqd)
				break;

			irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
		}

		return r->start;
	}

	return 0;
}

713
/**
714
 * i2c_new_device - instantiate an i2c device
715 716
 * @adap: the adapter managing the device
 * @info: describes one I2C device; bus_num is ignored
D
David Brownell 已提交
717
 * Context: can sleep
718
 *
719 720 721 722 723 724
 * Create an i2c device. Binding is handled through driver model
 * probe()/remove() methods.  A driver may be bound to this device when we
 * return from this function, or any later moment (e.g. maybe hotplugging will
 * load the driver module).  This call is not appropriate for use by mainboard
 * initialization logic, which usually runs during an arch_initcall() long
 * before any i2c_adapter could exist.
725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741
 *
 * This returns the new i2c client, which may be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
struct i2c_client *
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
{
	struct i2c_client	*client;
	int			status;

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

	client->adapter = adap;

	client->dev.platform_data = info->platform_data;
M
Marc Pignat 已提交
742
	client->flags = info->flags;
743
	client->addr = info->addr;
744

745
	client->irq = info->irq;
746 747 748
	if (!client->irq)
		client->irq = i2c_dev_irq_from_resources(info->resources,
							 info->num_resources);
749 750 751

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

752
	status = i2c_check_addr_validity(client->addr, client->flags);
753 754 755 756 757 758
	if (status) {
		dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
			client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
		goto out_err_silent;
	}

759
	/* Check for address business */
760
	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
761 762 763 764 765
	if (status)
		goto out_err;

	client->dev.parent = &client->adapter->dev;
	client->dev.bus = &i2c_bus_type;
766
	client->dev.type = &i2c_client_type;
767
	client->dev.of_node = of_node_get(info->of_node);
768
	client->dev.fwnode = info->fwnode;
769

770
	i2c_dev_set_name(adap, client, info);
771 772 773 774 775 776 777

	if (info->properties) {
		status = device_add_properties(&client->dev, info->properties);
		if (status) {
			dev_err(&adap->dev,
				"Failed to add properties to client %s: %d\n",
				client->name, status);
778
			goto out_err_put_of_node;
779 780 781
		}
	}

782 783
	status = device_register(&client->dev);
	if (status)
784
		goto out_free_props;
785 786 787 788

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

789
	return client;
790

791 792 793
out_free_props:
	if (info->properties)
		device_remove_properties(&client->dev);
794 795
out_err_put_of_node:
	of_node_put(info->of_node);
796
out_err:
797 798 799
	dev_err(&adap->dev,
		"Failed to register i2c client %s at 0x%02x (%d)\n",
		client->name, client->addr, status);
800
out_err_silent:
801 802
	kfree(client);
	return NULL;
803 804 805 806 807 808 809
}
EXPORT_SYMBOL_GPL(i2c_new_device);


/**
 * i2c_unregister_device - reverse effect of i2c_new_device()
 * @client: value returned from i2c_new_device()
D
David Brownell 已提交
810
 * Context: can sleep
811 812
 */
void i2c_unregister_device(struct i2c_client *client)
D
David Brownell 已提交
813
{
814 815
	if (!client)
		return;
816 817

	if (client->dev.of_node) {
818
		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
819 820 821
		of_node_put(client->dev.of_node);
	}

822 823
	if (ACPI_COMPANION(&client->dev))
		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
D
David Brownell 已提交
824 825
	device_unregister(&client->dev);
}
826
EXPORT_SYMBOL_GPL(i2c_unregister_device);
D
David Brownell 已提交
827 828


J
Jean Delvare 已提交
829 830 831 832 833
static const struct i2c_device_id dummy_id[] = {
	{ "dummy", 0 },
	{ },
};

834 835 836 837 838 839 840
static int dummy_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	return 0;
}

static int dummy_remove(struct i2c_client *client)
841 842 843 844 845 846
{
	return 0;
}

static struct i2c_driver dummy_driver = {
	.driver.name	= "dummy",
847 848
	.probe		= dummy_probe,
	.remove		= dummy_remove,
J
Jean Delvare 已提交
849
	.id_table	= dummy_id,
850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869
};

/**
 * i2c_new_dummy - return a new i2c device bound to a dummy driver
 * @adapter: the adapter managing the device
 * @address: seven bit address to be used
 * Context: can sleep
 *
 * This returns an I2C client bound to the "dummy" driver, intended for use
 * with devices that consume multiple addresses.  Examples of such chips
 * include various EEPROMS (like 24c04 and 24c08 models).
 *
 * These dummy devices have two main uses.  First, most I2C and SMBus calls
 * except i2c_transfer() need a client handle; the dummy will be that handle.
 * And second, this prevents the specified address from being bound to a
 * different driver.
 *
 * This returns the new i2c client, which should be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
Z
Zhenwen Xu 已提交
870
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
871 872
{
	struct i2c_board_info info = {
J
Jean Delvare 已提交
873
		I2C_BOARD_INFO("dummy", address),
874 875 876 877 878 879
	};

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

880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920
/**
 * i2c_new_secondary_device - Helper to get the instantiated secondary address
 * and create the associated device
 * @client: Handle to the primary client
 * @name: Handle to specify which secondary address to get
 * @default_addr: Used as a fallback if no secondary address was specified
 * Context: can sleep
 *
 * I2C clients can be composed of multiple I2C slaves bound together in a single
 * component. The I2C client driver then binds to the master I2C slave and needs
 * to create I2C dummy clients to communicate with all the other slaves.
 *
 * This function creates and returns an I2C dummy client whose I2C address is
 * retrieved from the platform firmware based on the given slave name. If no
 * address is specified by the firmware default_addr is used.
 *
 * On DT-based platforms the address is retrieved from the "reg" property entry
 * cell whose "reg-names" value matches the slave name.
 *
 * This returns the new i2c client, which should be saved for later use with
 * i2c_unregister_device(); or NULL to indicate an error.
 */
struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
						const char *name,
						u16 default_addr)
{
	struct device_node *np = client->dev.of_node;
	u32 addr = default_addr;
	int i;

	if (np) {
		i = of_property_match_string(np, "reg-names", name);
		if (i >= 0)
			of_property_read_u32_index(np, "reg", i, &addr);
	}

	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
	return i2c_new_dummy(client->adapter, addr);
}
EXPORT_SYMBOL_GPL(i2c_new_secondary_device);

921 922
/* ------------------------------------------------------------------------- */

D
David Brownell 已提交
923 924
/* I2C bus adapters -- one roots each I2C or SMBUS segment */

A
Adrian Bunk 已提交
925
static void i2c_adapter_dev_release(struct device *dev)
L
Linus Torvalds 已提交
926
{
927
	struct i2c_adapter *adap = to_i2c_adapter(dev);
L
Linus Torvalds 已提交
928 929 930
	complete(&adap->dev_released);
}

931
unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
932 933 934 935 936 937
{
	unsigned int depth = 0;

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

938 939 940
	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
		  "adapter depth exceeds lockdep subclass limit\n");

941 942
	return depth;
}
943
EXPORT_SYMBOL_GPL(i2c_adapter_depth);
944

945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988
/*
 * Let users instantiate I2C devices through sysfs. This can be used when
 * platform initialization code doesn't contain the proper data for
 * whatever reason. Also useful for drivers that do device detection and
 * detection fails, either because the device uses an unexpected address,
 * or this is a compatible device with different ID register values.
 *
 * Parameter checking may look overzealous, but we really don't want
 * the user to provide incorrect parameters.
 */
static ssize_t
i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
		     const char *buf, size_t count)
{
	struct i2c_adapter *adap = to_i2c_adapter(dev);
	struct i2c_board_info info;
	struct i2c_client *client;
	char *blank, end;
	int res;

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

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

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

989 990 991 992 993 994 995 996 997 998
	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
		info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
		info.flags |= I2C_CLIENT_TEN;
	}

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

999 1000
	client = i2c_new_device(adap, &info);
	if (!client)
1001
		return -EINVAL;
1002 1003

	/* Keep track of the added device */
1004
	mutex_lock(&adap->userspace_clients_lock);
1005
	list_add_tail(&client->detected, &adap->userspace_clients);
1006
	mutex_unlock(&adap->userspace_clients_lock);
1007 1008 1009 1010 1011
	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
		 info.type, info.addr);

	return count;
}
1012
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045

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

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

	/* Make sure the device was added through sysfs */
	res = -ENOENT;
1046 1047
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1048 1049
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
1050
		if (i2c_encode_flags_to_addr(client) == addr) {
1051 1052 1053 1054 1055 1056 1057 1058 1059
			dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
				 "delete_device", client->name, client->addr);

			list_del(&client->detected);
			i2c_unregister_device(client);
			res = count;
			break;
		}
	}
1060
	mutex_unlock(&adap->userspace_clients_lock);
1061 1062 1063 1064 1065 1066

	if (res < 0)
		dev_err(dev, "%s: Can't find device in list\n",
			"delete_device");
	return res;
}
1067 1068
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
				   i2c_sysfs_delete_device);
1069 1070 1071 1072 1073 1074 1075

static struct attribute *i2c_adapter_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_new_device.attr,
	&dev_attr_delete_device.attr,
	NULL
};
1076
ATTRIBUTE_GROUPS(i2c_adapter);
1077

1078
struct device_type i2c_adapter_type = {
1079
	.groups		= i2c_adapter_groups,
1080
	.release	= i2c_adapter_dev_release,
L
Linus Torvalds 已提交
1081
};
1082
EXPORT_SYMBOL_GPL(i2c_adapter_type);
L
Linus Torvalds 已提交
1083

1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100
/**
 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
 * @dev: device, probably from some driver model iterator
 *
 * When traversing the driver model tree, perhaps using driver model
 * iterators like @device_for_each_child(), you can't assume very much
 * about the nodes you find.  Use this function to avoid oopses caused
 * by wrongly treating some non-I2C device as an i2c_adapter.
 */
struct i2c_adapter *i2c_verify_adapter(struct device *dev)
{
	return (dev->type == &i2c_adapter_type)
			? to_i2c_adapter(dev)
			: NULL;
}
EXPORT_SYMBOL(i2c_verify_adapter);

1101 1102 1103 1104
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;
#endif

1105 1106 1107 1108
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
	struct i2c_devinfo	*devinfo;

1109
	down_read(&__i2c_board_lock);
1110 1111 1112 1113
	list_for_each_entry(devinfo, &__i2c_board_list, list) {
		if (devinfo->busnum == adapter->nr
				&& !i2c_new_device(adapter,
						&devinfo->board_info))
Z
Zhenwen Xu 已提交
1114 1115
			dev_err(&adapter->dev,
				"Can't create device at 0x%02x\n",
1116 1117
				devinfo->board_info.addr);
	}
1118
	up_read(&__i2c_board_lock);
1119 1120
}

J
Jean Delvare 已提交
1121 1122
static int i2c_do_add_adapter(struct i2c_driver *driver,
			      struct i2c_adapter *adap)
1123
{
1124 1125 1126 1127
	/* Detect supported devices on that bus, and instantiate them */
	i2c_detect(adap, driver);

	/* Let legacy drivers scan this bus for matching devices */
1128
	if (driver->attach_adapter) {
J
Jean Delvare 已提交
1129 1130
		dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
			 driver->driver.name);
1131 1132
		dev_warn(&adap->dev,
			 "Please use another way to instantiate your i2c_client\n");
1133 1134 1135 1136 1137 1138
		/* We ignore the return code; if it fails, too bad */
		driver->attach_adapter(adap);
	}
	return 0;
}

J
Jean Delvare 已提交
1139 1140 1141 1142 1143
static int __process_new_adapter(struct device_driver *d, void *data)
{
	return i2c_do_add_adapter(to_i2c_driver(d), data);
}

1144 1145 1146 1147 1148 1149
static const struct i2c_lock_operations i2c_adapter_lock_ops = {
	.lock_bus =    i2c_adapter_lock_bus,
	.trylock_bus = i2c_adapter_trylock_bus,
	.unlock_bus =  i2c_adapter_unlock_bus,
};

1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222
static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
{
	struct irq_domain *domain = adap->host_notify_domain;
	irq_hw_number_t hwirq;

	if (!domain)
		return;

	for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
		irq_dispose_mapping(irq_find_mapping(domain, hwirq));

	irq_domain_remove(domain);
	adap->host_notify_domain = NULL;
}

static int i2c_host_notify_irq_map(struct irq_domain *h,
					  unsigned int virq,
					  irq_hw_number_t hw_irq_num)
{
	irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);

	return 0;
}

static const struct irq_domain_ops i2c_host_notify_irq_ops = {
	.map = i2c_host_notify_irq_map,
};

static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
{
	struct irq_domain *domain;

	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
		return 0;

	domain = irq_domain_create_linear(adap->dev.fwnode,
					  I2C_ADDR_7BITS_COUNT,
					  &i2c_host_notify_irq_ops, adap);
	if (!domain)
		return -ENOMEM;

	adap->host_notify_domain = domain;

	return 0;
}

/**
 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
 * I2C client.
 * @adap: the adapter
 * @addr: the I2C address of the notifying device
 * Context: can't sleep
 *
 * Helper function to be called from an I2C bus driver's interrupt
 * handler. It will schedule the Host Notify IRQ.
 */
int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
{
	int irq;

	if (!adap)
		return -EINVAL;

	irq = irq_find_mapping(adap->host_notify_domain, addr);
	if (irq <= 0)
		return -ENXIO;

	generic_handle_irq(irq);

	return 0;
}
EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);

1223
static int i2c_register_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1224
{
1225
	int res = -EINVAL;
L
Linus Torvalds 已提交
1226

1227
	/* Can't register until after driver model init */
1228
	if (WARN_ON(!is_registered)) {
1229 1230 1231
		res = -EAGAIN;
		goto out_list;
	}
1232

1233
	/* Sanity checks */
1234
	if (WARN(!adap->name[0], "i2c adapter has no name"))
1235
		goto out_list;
1236 1237

	if (!adap->algo) {
W
Wolfram Sang 已提交
1238
		pr_err("adapter '%s': no algo supplied!\n", adap->name);
1239
		goto out_list;
1240 1241
	}

1242 1243
	if (!adap->lock_ops)
		adap->lock_ops = &i2c_adapter_lock_ops;
1244

1245
	rt_mutex_init(&adap->bus_lock);
1246
	rt_mutex_init(&adap->mux_lock);
1247
	mutex_init(&adap->userspace_clients_lock);
1248
	INIT_LIST_HEAD(&adap->userspace_clients);
L
Linus Torvalds 已提交
1249

1250 1251 1252 1253
	/* Set default timeout to 1 second if not already set */
	if (adap->timeout == 0)
		adap->timeout = HZ;

1254 1255 1256 1257 1258 1259 1260 1261
	/* register soft irqs for Host Notify */
	res = i2c_setup_host_notify_irq_domain(adap);
	if (res) {
		pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
		       adap->name, res);
		goto out_list;
	}

1262
	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1263 1264
	adap->dev.bus = &i2c_bus_type;
	adap->dev.type = &i2c_adapter_type;
1265
	res = device_register(&adap->dev);
1266
	if (res) {
W
Wolfram Sang 已提交
1267
		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1268
		goto out_list;
1269
	}
L
Linus Torvalds 已提交
1270

1271 1272 1273 1274
	res = of_i2c_setup_smbus_alert(adap);
	if (res)
		goto out_reg;

1275 1276
	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

1277
	pm_runtime_no_callbacks(&adap->dev);
1278
	pm_suspend_ignore_children(&adap->dev, true);
1279
	pm_runtime_enable(&adap->dev);
1280

1281 1282 1283 1284 1285 1286 1287 1288
#ifdef CONFIG_I2C_COMPAT
	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
				       adap->dev.parent);
	if (res)
		dev_warn(&adap->dev,
			 "Failed to create compatibility class link\n");
#endif

1289
	i2c_init_recovery(adap);
1290

1291
	/* create pre-declared device nodes */
1292
	of_i2c_register_devices(adap);
1293 1294
	i2c_acpi_register_devices(adap);
	i2c_acpi_install_space_handler(adap);
1295

1296 1297 1298
	if (adap->nr < __i2c_first_dynamic_bus_num)
		i2c_scan_static_board_info(adap);

1299
	/* Notify drivers */
1300
	mutex_lock(&core_lock);
J
Jean Delvare 已提交
1301
	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
J
Jean Delvare 已提交
1302
	mutex_unlock(&core_lock);
1303 1304

	return 0;
1305

1306 1307 1308 1309
out_reg:
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);
1310
out_list:
1311
	mutex_lock(&core_lock);
1312
	idr_remove(&i2c_adapter_idr, adap->nr);
1313 1314
	mutex_unlock(&core_lock);
	return res;
L
Linus Torvalds 已提交
1315 1316
}

1317 1318 1319 1320 1321 1322 1323 1324 1325
/**
 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
 * @adap: the adapter to register (with adap->nr initialized)
 * Context: can sleep
 *
 * See i2c_add_numbered_adapter() for details.
 */
static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
1326
	int id;
1327 1328

	mutex_lock(&core_lock);
1329
	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1330
	mutex_unlock(&core_lock);
1331
	if (WARN(id < 0, "couldn't get idr"))
1332 1333 1334 1335 1336
		return id == -ENOSPC ? -EBUSY : id;

	return i2c_register_adapter(adap);
}

1337 1338 1339
/**
 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
 * @adapter: the adapter to add
D
David Brownell 已提交
1340
 * Context: can sleep
1341 1342
 *
 * This routine is used to declare an I2C adapter when its bus number
1343 1344 1345
 * doesn't matter or when its bus number is specified by an dt alias.
 * Examples of bases when the bus number doesn't matter: I2C adapters
 * dynamically added by USB links or PCI plugin cards.
1346 1347 1348 1349 1350 1351 1352
 *
 * When this returns zero, a new bus number was allocated and stored
 * in adap->nr, and the specified adapter became available for clients.
 * Otherwise, a negative errno value is returned.
 */
int i2c_add_adapter(struct i2c_adapter *adapter)
{
1353
	struct device *dev = &adapter->dev;
T
Tejun Heo 已提交
1354
	int id;
1355

1356 1357 1358 1359 1360 1361 1362 1363
	if (dev->of_node) {
		id = of_alias_get_id(dev->of_node, "i2c");
		if (id >= 0) {
			adapter->nr = id;
			return __i2c_add_numbered_adapter(adapter);
		}
	}

J
Jean Delvare 已提交
1364
	mutex_lock(&core_lock);
T
Tejun Heo 已提交
1365 1366
	id = idr_alloc(&i2c_adapter_idr, adapter,
		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
J
Jean Delvare 已提交
1367
	mutex_unlock(&core_lock);
1368
	if (WARN(id < 0, "couldn't get idr"))
T
Tejun Heo 已提交
1369
		return id;
1370 1371

	adapter->nr = id;
T
Tejun Heo 已提交
1372

1373 1374 1375 1376 1377 1378 1379
	return i2c_register_adapter(adapter);
}
EXPORT_SYMBOL(i2c_add_adapter);

/**
 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
 * @adap: the adapter to register (with adap->nr initialized)
D
David Brownell 已提交
1380
 * Context: can sleep
1381 1382
 *
 * This routine is used to declare an I2C adapter when its bus number
R
Randy Dunlap 已提交
1383 1384
 * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
 * or otherwise built in to the system's mainboard, and where i2c_board_info
1385 1386
 * is used to properly configure I2C devices.
 *
1387 1388 1389
 * If the requested bus number is set to -1, then this function will behave
 * identically to i2c_add_adapter, and will dynamically assign a bus number.
 *
1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401
 * If no devices have pre-been declared for this bus, then be sure to
 * register the adapter before any dynamically allocated ones.  Otherwise
 * the required bus ID may not be available.
 *
 * When this returns zero, the specified adapter became available for
 * clients using the bus number provided in adap->nr.  Also, the table
 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
 * and the appropriate driver model device nodes are created.  Otherwise, a
 * negative errno value is returned.
 */
int i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
1402 1403
	if (adap->nr == -1) /* -1 means dynamically assign bus id */
		return i2c_add_adapter(adap);
1404

1405
	return __i2c_add_numbered_adapter(adap);
1406 1407 1408
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);

L
Lars-Peter Clausen 已提交
1409
static void i2c_do_del_adapter(struct i2c_driver *driver,
J
Jean Delvare 已提交
1410
			      struct i2c_adapter *adapter)
1411
{
1412
	struct i2c_client *client, *_n;
1413

1414 1415
	/* Remove the devices we created ourselves as the result of hardware
	 * probing (using a driver's detect method) */
1416 1417 1418 1419 1420 1421 1422 1423
	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
		if (client->adapter == adapter) {
			dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
				client->name, client->addr);
			list_del(&client->detected);
			i2c_unregister_device(client);
		}
	}
1424 1425
}

1426
static int __unregister_client(struct device *dev, void *dummy)
1427 1428 1429 1430 1431 1432 1433 1434
{
	struct i2c_client *client = i2c_verify_client(dev);
	if (client && strcmp(client->name, "dummy"))
		i2c_unregister_device(client);
	return 0;
}

static int __unregister_dummy(struct device *dev, void *dummy)
1435 1436
{
	struct i2c_client *client = i2c_verify_client(dev);
1437
	i2c_unregister_device(client);
1438 1439 1440
	return 0;
}

J
Jean Delvare 已提交
1441 1442
static int __process_removed_adapter(struct device_driver *d, void *data)
{
L
Lars-Peter Clausen 已提交
1443 1444
	i2c_do_del_adapter(to_i2c_driver(d), data);
	return 0;
J
Jean Delvare 已提交
1445 1446
}

D
David Brownell 已提交
1447 1448 1449 1450 1451 1452 1453 1454
/**
 * i2c_del_adapter - unregister I2C adapter
 * @adap: the adapter being unregistered
 * Context: can sleep
 *
 * This unregisters an I2C adapter which was previously registered
 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
 */
1455
void i2c_del_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1456
{
1457
	struct i2c_adapter *found;
1458
	struct i2c_client *client, *next;
L
Linus Torvalds 已提交
1459 1460

	/* First make sure that this adapter was ever added */
1461 1462 1463 1464
	mutex_lock(&core_lock);
	found = idr_find(&i2c_adapter_idr, adap->nr);
	mutex_unlock(&core_lock);
	if (found != adap) {
W
Wolfram Sang 已提交
1465
		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1466
		return;
L
Linus Torvalds 已提交
1467 1468
	}

1469
	i2c_acpi_remove_space_handler(adap);
1470
	/* Tell drivers about this removal */
1471
	mutex_lock(&core_lock);
L
Lars-Peter Clausen 已提交
1472
	bus_for_each_drv(&i2c_bus_type, NULL, adap,
J
Jean Delvare 已提交
1473
			       __process_removed_adapter);
1474
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1475

1476
	/* Remove devices instantiated from sysfs */
1477 1478
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1479 1480 1481 1482 1483 1484
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
			client->addr);
		list_del(&client->detected);
		i2c_unregister_device(client);
1485
	}
1486
	mutex_unlock(&adap->userspace_clients_lock);
1487

1488
	/* Detach any active clients. This can't fail, thus we do not
1489 1490 1491 1492
	 * check the returned value. This is a two-pass process, because
	 * we can't remove the dummy devices during the first pass: they
	 * could have been instantiated by real devices wishing to clean
	 * them up properly, so we give them a chance to do that first. */
L
Lars-Peter Clausen 已提交
1493 1494
	device_for_each_child(&adap->dev, NULL, __unregister_client);
	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
L
Linus Torvalds 已提交
1495

1496 1497 1498 1499 1500
#ifdef CONFIG_I2C_COMPAT
	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
				 adap->dev.parent);
#endif

1501 1502 1503
	/* device name is gone after device_unregister */
	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);

1504 1505
	pm_runtime_disable(&adap->dev);

1506 1507
	i2c_host_notify_irq_teardown(adap);

1508 1509 1510 1511 1512
	/* wait until all references to the device are gone
	 *
	 * FIXME: This is old code and should ideally be replaced by an
	 * alternative which results in decoupling the lifetime of the struct
	 * device from the i2c_adapter, like spi or netdev do. Any solution
1513
	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1514
	 */
L
Linus Torvalds 已提交
1515 1516 1517 1518
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);

1519
	/* free bus id */
1520
	mutex_lock(&core_lock);
L
Linus Torvalds 已提交
1521
	idr_remove(&i2c_adapter_idr, adap->nr);
1522
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1523

1524 1525 1526
	/* Clear the device structure in case this adapter is ever going to be
	   added again */
	memset(&adap->dev, 0, sizeof(adap->dev));
L
Linus Torvalds 已提交
1527
}
D
David Brownell 已提交
1528
EXPORT_SYMBOL(i2c_del_adapter);
L
Linus Torvalds 已提交
1529

1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578
/**
 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
 * @dev: The device to scan for I2C timing properties
 * @t: the i2c_timings struct to be filled with values
 * @use_defaults: bool to use sane defaults derived from the I2C specification
 *		  when properties are not found, otherwise use 0
 *
 * Scan the device for the generic I2C properties describing timing parameters
 * for the signal and fill the given struct with the results. If a property was
 * not found and use_defaults was true, then maximum timings are assumed which
 * are derived from the I2C specification. If use_defaults is not used, the
 * results will be 0, so drivers can apply their own defaults later. The latter
 * is mainly intended for avoiding regressions of existing drivers which want
 * to switch to this function. New drivers almost always should use the defaults.
 */

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

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

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

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

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

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

	ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
	if (ret && use_defaults)
		t->sda_fall_ns = t->scl_fall_ns;
1579 1580

	device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1581 1582 1583
}
EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);

D
David Brownell 已提交
1584 1585
/* ------------------------------------------------------------------------- */

J
Jean Delvare 已提交
1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597
int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
{
	int res;

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

	return res;
}
EXPORT_SYMBOL_GPL(i2c_for_each_dev);

J
Jean Delvare 已提交
1598
static int __process_new_driver(struct device *dev, void *data)
D
Dave Young 已提交
1599
{
1600 1601
	if (dev->type != &i2c_adapter_type)
		return 0;
J
Jean Delvare 已提交
1602
	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
D
Dave Young 已提交
1603 1604
}

D
David Brownell 已提交
1605 1606
/*
 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1607
 * i2c slave chips, on a bus instance associated with some i2c_adapter.
L
Linus Torvalds 已提交
1608 1609
 */

1610
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
L
Linus Torvalds 已提交
1611
{
1612
	int res;
L
Linus Torvalds 已提交
1613

1614
	/* Can't register until after driver model init */
1615
	if (WARN_ON(!is_registered))
1616 1617
		return -EAGAIN;

L
Linus Torvalds 已提交
1618
	/* add the driver to the list of i2c drivers in the driver core */
1619
	driver->driver.owner = owner;
L
Linus Torvalds 已提交
1620
	driver->driver.bus = &i2c_bus_type;
1621
	INIT_LIST_HEAD(&driver->clients);
L
Linus Torvalds 已提交
1622

1623
	/* When registration returns, the driver core
1624 1625
	 * will have called probe() for all matching-but-unbound devices.
	 */
L
Linus Torvalds 已提交
1626 1627
	res = driver_register(&driver->driver);
	if (res)
1628
		return res;
D
David Brownell 已提交
1629

W
Wolfram Sang 已提交
1630
	pr_debug("driver [%s] registered\n", driver->driver.name);
L
Linus Torvalds 已提交
1631

1632
	/* Walk the adapters that are already present */
J
Jean Delvare 已提交
1633
	i2c_for_each_dev(driver, __process_new_driver);
1634

D
Dave Young 已提交
1635 1636 1637 1638
	return 0;
}
EXPORT_SYMBOL(i2c_register_driver);

J
Jean Delvare 已提交
1639
static int __process_removed_driver(struct device *dev, void *data)
D
Dave Young 已提交
1640
{
L
Lars-Peter Clausen 已提交
1641 1642 1643
	if (dev->type == &i2c_adapter_type)
		i2c_do_del_adapter(data, to_i2c_adapter(dev));
	return 0;
L
Linus Torvalds 已提交
1644 1645
}

D
David Brownell 已提交
1646 1647 1648
/**
 * i2c_del_driver - unregister I2C driver
 * @driver: the driver being unregistered
D
David Brownell 已提交
1649
 * Context: can sleep
D
David Brownell 已提交
1650
 */
1651
void i2c_del_driver(struct i2c_driver *driver)
L
Linus Torvalds 已提交
1652
{
J
Jean Delvare 已提交
1653
	i2c_for_each_dev(driver, __process_removed_driver);
L
Linus Torvalds 已提交
1654 1655

	driver_unregister(&driver->driver);
W
Wolfram Sang 已提交
1656
	pr_debug("driver [%s] unregistered\n", driver->driver.name);
L
Linus Torvalds 已提交
1657
}
D
David Brownell 已提交
1658
EXPORT_SYMBOL(i2c_del_driver);
L
Linus Torvalds 已提交
1659

D
David Brownell 已提交
1660 1661
/* ------------------------------------------------------------------------- */

1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673
/**
 * i2c_use_client - increments the reference count of the i2c client structure
 * @client: the client being referenced
 *
 * Each live reference to a client should be refcounted. The driver model does
 * that automatically as part of driver binding, so that most drivers don't
 * need to do this explicitly: they hold a reference until they're unbound
 * from the device.
 *
 * A pointer to the client with the incremented reference counter is returned.
 */
struct i2c_client *i2c_use_client(struct i2c_client *client)
L
Linus Torvalds 已提交
1674
{
1675 1676 1677
	if (client && get_device(&client->dev))
		return client;
	return NULL;
L
Linus Torvalds 已提交
1678
}
D
David Brownell 已提交
1679
EXPORT_SYMBOL(i2c_use_client);
L
Linus Torvalds 已提交
1680

1681 1682 1683 1684 1685 1686 1687
/**
 * i2c_release_client - release a use of the i2c client structure
 * @client: the client being no longer referenced
 *
 * Must be called when a user of a client is finished with it.
 */
void i2c_release_client(struct i2c_client *client)
L
Linus Torvalds 已提交
1688
{
1689 1690
	if (client)
		put_device(&client->dev);
L
Linus Torvalds 已提交
1691
}
D
David Brownell 已提交
1692
EXPORT_SYMBOL(i2c_release_client);
L
Linus Torvalds 已提交
1693

1694 1695 1696 1697 1698 1699 1700 1701 1702
struct i2c_cmd_arg {
	unsigned	cmd;
	void		*arg;
};

static int i2c_cmd(struct device *dev, void *_arg)
{
	struct i2c_client	*client = i2c_verify_client(dev);
	struct i2c_cmd_arg	*arg = _arg;
1703 1704 1705 1706
	struct i2c_driver	*driver;

	if (!client || !client->dev.driver)
		return 0;
1707

1708 1709 1710
	driver = to_i2c_driver(client->dev.driver);
	if (driver->command)
		driver->command(client, arg->cmd, arg->arg);
1711 1712 1713
	return 0;
}

L
Linus Torvalds 已提交
1714 1715
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
{
1716
	struct i2c_cmd_arg	cmd_arg;
L
Linus Torvalds 已提交
1717

1718 1719 1720
	cmd_arg.cmd = cmd;
	cmd_arg.arg = arg;
	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
L
Linus Torvalds 已提交
1721
}
D
David Brownell 已提交
1722
EXPORT_SYMBOL(i2c_clients_command);
L
Linus Torvalds 已提交
1723 1724 1725 1726 1727

static int __init i2c_init(void)
{
	int retval;

1728 1729 1730 1731 1732 1733 1734
	retval = of_alias_get_highest_id("i2c");

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

L
Linus Torvalds 已提交
1735 1736 1737
	retval = bus_register(&i2c_bus_type);
	if (retval)
		return retval;
1738 1739 1740

	is_registered = true;

1741 1742 1743 1744 1745 1746 1747
#ifdef CONFIG_I2C_COMPAT
	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
	if (!i2c_adapter_compat_class) {
		retval = -ENOMEM;
		goto bus_err;
	}
#endif
1748 1749
	retval = i2c_add_driver(&dummy_driver);
	if (retval)
1750
		goto class_err;
1751 1752 1753

	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1754 1755
	if (IS_ENABLED(CONFIG_ACPI))
		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1756

1757 1758
	return 0;

1759 1760 1761
class_err:
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
1762
bus_err:
1763
#endif
1764
	is_registered = false;
1765 1766
	bus_unregister(&i2c_bus_type);
	return retval;
L
Linus Torvalds 已提交
1767 1768 1769 1770
}

static void __exit i2c_exit(void)
{
1771 1772
	if (IS_ENABLED(CONFIG_ACPI))
		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1773 1774
	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1775
	i2c_del_driver(&dummy_driver);
1776 1777 1778
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
#endif
L
Linus Torvalds 已提交
1779
	bus_unregister(&i2c_bus_type);
1780
	tracepoint_synchronize_unregister();
L
Linus Torvalds 已提交
1781 1782
}

D
David Brownell 已提交
1783 1784 1785 1786
/* We must initialize early, because some subsystems register i2c drivers
 * in subsys_initcall() code, but are linked (and initialized) before i2c.
 */
postcore_initcall(i2c_init);
L
Linus Torvalds 已提交
1787 1788 1789 1790 1791 1792 1793
module_exit(i2c_exit);

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

W
Wolfram Sang 已提交
1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843
/* Check if val is exceeding the quirk IFF quirk is non 0 */
#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))

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

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

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

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

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

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

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

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

			do_len_check = false;
		}
	}

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

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

		if (msgs[i].flags & I2C_M_RD) {
			if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
				return i2c_quirk_error(adap, &msgs[i], "msg too long");
1844 1845 1846

			if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
				return i2c_quirk_error(adap, &msgs[i], "no zero length");
W
Wolfram Sang 已提交
1847 1848 1849
		} else {
			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
				return i2c_quirk_error(adap, &msgs[i], "msg too long");
1850 1851 1852

			if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
				return i2c_quirk_error(adap, &msgs[i], "no zero length");
W
Wolfram Sang 已提交
1853 1854 1855 1856 1857 1858
		}
	}

	return 0;
}

1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875
/**
 * __i2c_transfer - unlocked flavor of i2c_transfer
 * @adap: Handle to I2C bus
 * @msgs: One or more messages to execute before STOP is issued to
 *	terminate the operation; each message begins with a START.
 * @num: Number of messages to be executed.
 *
 * Returns negative errno, else the number of messages executed.
 *
 * Adapter lock must be held when calling this function. No debug logging
 * takes place. adap->algo->master_xfer existence isn't checked.
 */
int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	unsigned long orig_jiffies;
	int ret, try;

1876 1877 1878
	if (WARN_ON(!msgs || num < 1))
		return -EINVAL;

W
Wolfram Sang 已提交
1879 1880 1881
	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
		return -EOPNOTSUPP;

1882 1883
	/*
	 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1884 1885 1886
	 * enabled.  This is an efficient way of keeping the for-loop from
	 * being executed when not needed.
	 */
1887
	if (static_branch_unlikely(&i2c_trace_msg_key)) {
1888 1889 1890 1891 1892 1893 1894 1895
		int i;
		for (i = 0; i < num; i++)
			if (msgs[i].flags & I2C_M_RD)
				trace_i2c_read(adap, &msgs[i], i);
			else
				trace_i2c_write(adap, &msgs[i], i);
	}

1896 1897 1898 1899 1900 1901 1902 1903 1904 1905
	/* Retry automatically on arbitration loss */
	orig_jiffies = jiffies;
	for (ret = 0, try = 0; try <= adap->retries; try++) {
		ret = adap->algo->master_xfer(adap, msgs, num);
		if (ret != -EAGAIN)
			break;
		if (time_after(jiffies, orig_jiffies + adap->timeout))
			break;
	}

1906
	if (static_branch_unlikely(&i2c_trace_msg_key)) {
1907 1908 1909 1910
		int i;
		for (i = 0; i < ret; i++)
			if (msgs[i].flags & I2C_M_RD)
				trace_i2c_reply(adap, &msgs[i], i);
1911
		trace_i2c_result(adap, num, ret);
1912 1913
	}

1914 1915 1916 1917
	return ret;
}
EXPORT_SYMBOL(__i2c_transfer);

1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929
/**
 * i2c_transfer - execute a single or combined I2C message
 * @adap: Handle to I2C bus
 * @msgs: One or more messages to execute before STOP is issued to
 *	terminate the operation; each message begins with a START.
 * @num: Number of messages to be executed.
 *
 * Returns negative errno, else the number of messages executed.
 *
 * Note that there is no requirement that each message be sent to
 * the same slave address, although that is the most common model.
 */
Z
Zhenwen Xu 已提交
1930
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
L
Linus Torvalds 已提交
1931
{
1932
	int ret;
L
Linus Torvalds 已提交
1933

1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950
	/* REVISIT the fault reporting model here is weak:
	 *
	 *  - When we get an error after receiving N bytes from a slave,
	 *    there is no way to report "N".
	 *
	 *  - When we get a NAK after transmitting N bytes to a slave,
	 *    there is no way to report "N" ... or to let the master
	 *    continue executing the rest of this combined message, if
	 *    that's the appropriate response.
	 *
	 *  - When for example "num" is two and we successfully complete
	 *    the first message but get an error part way through the
	 *    second, it's unclear whether that should be reported as
	 *    one (discarding status on the second message) or errno
	 *    (discarding status on the first one).
	 */

L
Linus Torvalds 已提交
1951 1952 1953
	if (adap->algo->master_xfer) {
#ifdef DEBUG
		for (ret = 0; ret < num; ret++) {
1954 1955 1956 1957
			dev_dbg(&adap->dev,
				"master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
				ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
				msgs[ret].addr, msgs[ret].len,
1958
				(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
L
Linus Torvalds 已提交
1959 1960 1961
		}
#endif

1962
		if (in_atomic() || irqs_disabled()) {
1963
			ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1964 1965 1966 1967
			if (!ret)
				/* I2C activity is ongoing. */
				return -EAGAIN;
		} else {
1968
			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1969 1970
		}

1971
		ret = __i2c_transfer(adap, msgs, num);
1972
		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
1973 1974 1975 1976

		return ret;
	} else {
		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
D
David Brownell 已提交
1977
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
1978 1979
	}
}
D
David Brownell 已提交
1980
EXPORT_SYMBOL(i2c_transfer);
L
Linus Torvalds 已提交
1981

1982
/**
1983 1984
 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
 *			       to/from a buffer
1985
 * @client: Handle to slave device
1986 1987 1988
 * @buf: Where the data is stored
 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1989
 *
1990
 * Returns negative errno, or else the number of bytes transferred.
1991
 */
1992 1993
int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
			      int count, u16 flags)
L
Linus Torvalds 已提交
1994 1995
{
	int ret;
1996 1997 1998 1999 2000 2001
	struct i2c_msg msg = {
		.addr = client->addr,
		.flags = flags | (client->flags & I2C_M_TEN),
		.len = count,
		.buf = buf,
	};
2002

2003
	ret = i2c_transfer(client->adapter, &msg, 1);
2004

2005
	/*
2006 2007
	 * If everything went ok (i.e. 1 msg transferred), return #bytes
	 * transferred, else error code.
2008
	 */
2009
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2010
}
2011
EXPORT_SYMBOL(i2c_transfer_buffer_flags);
L
Linus Torvalds 已提交
2012

2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
/**
 * i2c_get_device_id - get manufacturer, part id and die revision of a device
 * @client: The device to query
 * @id: The queried information
 *
 * Returns negative errno on error, zero on success.
 */
int i2c_get_device_id(const struct i2c_client *client,
		      struct i2c_device_identity *id)
{
	struct i2c_adapter *adap = client->adapter;
	union i2c_smbus_data raw_id;
	int ret;

	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
		return -EOPNOTSUPP;

	raw_id.block[0] = 3;
	ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
			     I2C_SMBUS_READ, client->addr << 1,
			     I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
	if (ret)
		return ret;

	id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
	id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
	id->die_revision = raw_id.block[3] & 0x7;
	return 0;
}
EXPORT_SYMBOL_GPL(i2c_get_device_id);

L
Linus Torvalds 已提交
2044 2045 2046 2047 2048 2049
/* ----------------------------------------------------
 * the i2c address scanning function
 * Will not work for 10-bit addresses!
 * ----------------------------------------------------
 */

2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073
/*
 * Legacy default probe function, mostly relevant for SMBus. The default
 * probe method is a quick write, but it is known to corrupt the 24RF08
 * EEPROMs due to a state machine bug, and could also irreversibly
 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
 * we use a short byte read instead. Also, some bus drivers don't implement
 * quick write, so we fallback to a byte read in that case too.
 * On x86, there is another special case for FSC hardware monitoring chips,
 * which want regular byte reads (address 0x73.) Fortunately, these are the
 * only known chips using this I2C address on PC hardware.
 * Returns 1 if probe succeeded, 0 if not.
 */
static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
{
	int err;
	union i2c_smbus_data dummy;

#ifdef CONFIG_X86
	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
				     I2C_SMBUS_BYTE_DATA, &dummy);
	else
#endif
2074 2075
	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2076 2077
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
				     I2C_SMBUS_QUICK, NULL);
2078 2079 2080 2081
	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
				     I2C_SMBUS_BYTE, &dummy);
	else {
2082 2083
		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
			 addr);
2084 2085
		err = -EOPNOTSUPP;
	}
2086 2087 2088 2089

	return err >= 0;
}

J
Jean Delvare 已提交
2090
static int i2c_detect_address(struct i2c_client *temp_client,
2091 2092 2093 2094 2095 2096 2097 2098
			      struct i2c_driver *driver)
{
	struct i2c_board_info info;
	struct i2c_adapter *adapter = temp_client->adapter;
	int addr = temp_client->addr;
	int err;

	/* Make sure the address is valid */
2099
	err = i2c_check_7bit_addr_validity_strict(addr);
2100
	if (err) {
2101 2102
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
			 addr);
2103
		return err;
2104 2105
	}

2106
	/* Skip if already in use (7 bit, no need to encode flags) */
2107
	if (i2c_check_addr_busy(adapter, addr))
2108 2109
		return 0;

J
Jean Delvare 已提交
2110
	/* Make sure there is something at this address */
2111 2112
	if (!i2c_default_probe(adapter, addr))
		return 0;
2113 2114 2115 2116

	/* Finally call the custom detection function */
	memset(&info, 0, sizeof(struct i2c_board_info));
	info.addr = addr;
2117
	err = driver->detect(temp_client, &info);
2118 2119 2120 2121 2122 2123 2124 2125
	if (err) {
		/* -ENODEV is returned if the detection fails. We catch it
		   here as this isn't an error. */
		return err == -ENODEV ? 0 : err;
	}

	/* Consistency check */
	if (info.type[0] == '\0') {
2126 2127 2128
		dev_err(&adapter->dev,
			"%s detection function provided no name for 0x%x\n",
			driver->driver.name, addr);
2129 2130 2131 2132
	} else {
		struct i2c_client *client;

		/* Detection succeeded, instantiate the device */
2133 2134 2135 2136 2137 2138 2139
		if (adapter->class & I2C_CLASS_DEPRECATED)
			dev_warn(&adapter->dev,
				"This adapter will soon drop class based instantiation of devices. "
				"Please make sure client 0x%02x gets instantiated by other means. "
				"Check 'Documentation/i2c/instantiating-devices' for details.\n",
				info.addr);

2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153
		dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
			info.type, info.addr);
		client = i2c_new_device(adapter, &info);
		if (client)
			list_add_tail(&client->detected, &driver->clients);
		else
			dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
				info.type, info.addr);
	}
	return 0;
}

static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
{
2154
	const unsigned short *address_list;
2155 2156 2157 2158
	struct i2c_client *temp_client;
	int i, err = 0;
	int adap_id = i2c_adapter_id(adapter);

2159 2160
	address_list = driver->address_list;
	if (!driver->detect || !address_list)
2161 2162
		return 0;

2163 2164 2165
	/* Warn that the adapter lost class based instantiation */
	if (adapter->class == I2C_CLASS_DEPRECATED) {
		dev_dbg(&adapter->dev,
2166 2167
			"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
			"If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2168 2169 2170 2171
			driver->driver.name);
		return 0;
	}

J
Jean Delvare 已提交
2172 2173 2174 2175
	/* Stop here if the classes do not match */
	if (!(adapter->class & driver->class))
		return 0;

2176 2177 2178 2179 2180 2181
	/* Set up a temporary client to help detect callback */
	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
	if (!temp_client)
		return -ENOMEM;
	temp_client->adapter = adapter;

2182
	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2183 2184 2185
		dev_dbg(&adapter->dev,
			"found normal entry for adapter %d, addr 0x%02x\n",
			adap_id, address_list[i]);
2186
		temp_client->addr = address_list[i];
J
Jean Delvare 已提交
2187
		err = i2c_detect_address(temp_client, driver);
J
Jean Delvare 已提交
2188 2189
		if (unlikely(err))
			break;
2190 2191 2192 2193 2194 2195
	}

	kfree(temp_client);
	return err;
}

2196 2197 2198 2199 2200 2201 2202
int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
{
	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
			      I2C_SMBUS_QUICK, NULL) >= 0;
}
EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);

J
Jean Delvare 已提交
2203 2204 2205
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
		      struct i2c_board_info *info,
2206 2207
		      unsigned short const *addr_list,
		      int (*probe)(struct i2c_adapter *, unsigned short addr))
J
Jean Delvare 已提交
2208 2209 2210
{
	int i;

2211
	if (!probe)
2212
		probe = i2c_default_probe;
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	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
		/* Check address validity */
2216
		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2217 2218
			dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
				 addr_list[i]);
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			continue;
		}

2222
		/* Check address availability (7 bit, no need to encode flags) */
2223
		if (i2c_check_addr_busy(adap, addr_list[i])) {
2224 2225 2226
			dev_dbg(&adap->dev,
				"Address 0x%02x already in use, not probing\n",
				addr_list[i]);
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			continue;
		}

2230
		/* Test address responsiveness */
2231
		if (probe(adap, addr_list[i]))
2232
			break;
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	}

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

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

2245
struct i2c_adapter *i2c_get_adapter(int nr)
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{
	struct i2c_adapter *adapter;
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2248

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	mutex_lock(&core_lock);
2250
	adapter = idr_find(&i2c_adapter_idr, nr);
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	if (!adapter)
		goto exit;

	if (try_module_get(adapter->owner))
		get_device(&adapter->dev);
	else
2257 2258
		adapter = NULL;

2259
 exit:
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	mutex_unlock(&core_lock);
2261
	return adapter;
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}
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EXPORT_SYMBOL(i2c_get_adapter);
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void i2c_put_adapter(struct i2c_adapter *adap)
{
2267 2268 2269 2270 2271
	if (!adap)
		return;

	put_device(&adap->dev);
	module_put(adap->owner);
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}
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EXPORT_SYMBOL(i2c_put_adapter);
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2274

2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320
/**
 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
 * @msg: the message to be checked
 * @threshold: the minimum number of bytes for which using DMA makes sense
 *
 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
 *	   Or a valid pointer to be used with DMA. After use, release it by
 *	   calling i2c_release_dma_safe_msg_buf().
 *
 * This function must only be called from process context!
 */
u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
{
	if (msg->len < threshold)
		return NULL;

	if (msg->flags & I2C_M_DMA_SAFE)
		return msg->buf;

	pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
		 msg->addr, msg->len);

	if (msg->flags & I2C_M_RD)
		return kzalloc(msg->len, GFP_KERNEL);
	else
		return kmemdup(msg->buf, msg->len, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);

/**
 * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
 * @msg: the message to be synced with
 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
 */
void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
{
	if (!buf || buf == msg->buf)
		return;

	if (msg->flags & I2C_M_RD)
		memcpy(msg->buf, buf, msg->len);

	kfree(buf);
}
EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);

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MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");