i2c-core-base.c 62.6 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,
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 * deletion of detected devices are serialized
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 */
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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;

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	irq = irq_create_mapping(adap->host_notify_domain, client->addr);
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	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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	client->irq = 0;

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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)
542
{
543
	if (flags & I2C_CLIENT_TEN) {
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		/* 10-bit address, all values are valid */
545
		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)
{
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	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
590 591 592 593 594
	int result;

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

595 596
	if (!result && parent)
		result = i2c_check_mux_parents(parent, addr);
597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614

	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;
}

615 616
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
617
	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
618 619
	int result = 0;

620 621
	if (parent)
		result = i2c_check_mux_parents(parent, addr);
622 623 624 625 626 627

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

	return result;
628 629
}

630
/**
631
 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
632
 * @adapter: Target I2C bus segment
633 634
 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 *	locks only this branch in the adapter tree
635
 */
636 637
static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
				 unsigned int flags)
638
{
639
	rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
640 641 642
}

/**
643
 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
644
 * @adapter: Target I2C bus segment
645 646
 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	trylocks only this branch in the adapter tree
647
 */
648 649
static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
650
{
651
	return rt_mutex_trylock(&adapter->bus_lock);
652 653 654
}

/**
655
 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
656
 * @adapter: Target I2C bus segment
657 658
 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 *	unlocks only this branch in the adapter tree
659
 */
660 661
static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
				   unsigned int flags)
662
{
663
	rt_mutex_unlock(&adapter->bus_lock);
664 665
}

666
static void i2c_dev_set_name(struct i2c_adapter *adap,
667 668
			     struct i2c_client *client,
			     struct i2c_board_info const *info)
669 670 671
{
	struct acpi_device *adev = ACPI_COMPANION(&client->dev);

672 673 674 675 676
	if (info && info->dev_name) {
		dev_set_name(&client->dev, "i2c-%s", info->dev_name);
		return;
	}

677 678 679 680 681 682
	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),
683
		     i2c_encode_flags_to_addr(client));
684 685
}

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
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;
}

712
/**
713
 * i2c_new_device - instantiate an i2c device
714 715
 * @adap: the adapter managing the device
 * @info: describes one I2C device; bus_num is ignored
D
David Brownell 已提交
716
 * Context: can sleep
717
 *
718 719 720 721 722 723
 * 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.
724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
 *
 * 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
741
	client->flags = info->flags;
742
	client->addr = info->addr;
743

744
	client->irq = info->irq;
745 746 747
	if (!client->irq)
		client->irq = i2c_dev_irq_from_resources(info->resources,
							 info->num_resources);
748 749 750

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

751
	status = i2c_check_addr_validity(client->addr, client->flags);
752 753 754 755 756 757
	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;
	}

758
	/* Check for address business */
759
	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
760 761 762 763 764
	if (status)
		goto out_err;

	client->dev.parent = &client->adapter->dev;
	client->dev.bus = &i2c_bus_type;
765
	client->dev.type = &i2c_client_type;
766
	client->dev.of_node = of_node_get(info->of_node);
767
	client->dev.fwnode = info->fwnode;
768

769
	i2c_dev_set_name(adap, client, info);
770 771 772 773 774 775 776

	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);
777
			goto out_err_put_of_node;
778 779 780
		}
	}

781 782
	status = device_register(&client->dev);
	if (status)
783
		goto out_free_props;
784 785 786 787

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

788
	return client;
789

790 791 792
out_free_props:
	if (info->properties)
		device_remove_properties(&client->dev);
793 794
out_err_put_of_node:
	of_node_put(info->of_node);
795
out_err:
796 797 798
	dev_err(&adap->dev,
		"Failed to register i2c client %s at 0x%02x (%d)\n",
		client->name, client->addr, status);
799
out_err_silent:
800 801
	kfree(client);
	return NULL;
802 803 804 805 806 807 808
}
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
809
 * Context: can sleep
810 811
 */
void i2c_unregister_device(struct i2c_client *client)
D
David Brownell 已提交
812
{
813 814
	if (!client)
		return;
815 816

	if (client->dev.of_node) {
817
		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
818 819 820
		of_node_put(client->dev.of_node);
	}

821 822
	if (ACPI_COMPANION(&client->dev))
		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
D
David Brownell 已提交
823 824
	device_unregister(&client->dev);
}
825
EXPORT_SYMBOL_GPL(i2c_unregister_device);
D
David Brownell 已提交
826 827


J
Jean Delvare 已提交
828 829 830 831 832
static const struct i2c_device_id dummy_id[] = {
	{ "dummy", 0 },
	{ },
};

833 834 835 836 837 838 839
static int dummy_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	return 0;
}

static int dummy_remove(struct i2c_client *client)
840 841 842 843 844 845
{
	return 0;
}

static struct i2c_driver dummy_driver = {
	.driver.name	= "dummy",
846 847
	.probe		= dummy_probe,
	.remove		= dummy_remove,
J
Jean Delvare 已提交
848
	.id_table	= dummy_id,
849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868
};

/**
 * 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
869
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
870 871
{
	struct i2c_board_info info = {
J
Jean Delvare 已提交
872
		I2C_BOARD_INFO("dummy", address),
873 874 875 876 877 878
	};

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

879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919
/**
 * 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);

920 921
/* ------------------------------------------------------------------------- */

D
David Brownell 已提交
922 923
/* I2C bus adapters -- one roots each I2C or SMBUS segment */

A
Adrian Bunk 已提交
924
static void i2c_adapter_dev_release(struct device *dev)
L
Linus Torvalds 已提交
925
{
926
	struct i2c_adapter *adap = to_i2c_adapter(dev);
L
Linus Torvalds 已提交
927 928 929
	complete(&adap->dev_released);
}

930
unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
931 932 933 934 935 936
{
	unsigned int depth = 0;

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

937 938 939
	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
		  "adapter depth exceeds lockdep subclass limit\n");

940 941
	return depth;
}
942
EXPORT_SYMBOL_GPL(i2c_adapter_depth);
943

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
/*
 * 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;
	}

988 989 990 991 992 993 994 995 996 997
	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;
	}

998 999
	client = i2c_new_device(adap, &info);
	if (!client)
1000
		return -EINVAL;
1001 1002

	/* Keep track of the added device */
1003
	mutex_lock(&adap->userspace_clients_lock);
1004
	list_add_tail(&client->detected, &adap->userspace_clients);
1005
	mutex_unlock(&adap->userspace_clients_lock);
1006 1007 1008 1009 1010
	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
		 info.type, info.addr);

	return count;
}
1011
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1012 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

/*
 * 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;
1045 1046
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1047 1048
	list_for_each_entry_safe(client, next, &adap->userspace_clients,
				 detected) {
1049
		if (i2c_encode_flags_to_addr(client) == addr) {
1050 1051 1052 1053 1054 1055 1056 1057 1058
			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;
		}
	}
1059
	mutex_unlock(&adap->userspace_clients_lock);
1060 1061 1062 1063 1064 1065

	if (res < 0)
		dev_err(dev, "%s: Can't find device in list\n",
			"delete_device");
	return res;
}
1066 1067
static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
				   i2c_sysfs_delete_device);
1068 1069 1070 1071 1072 1073 1074

static struct attribute *i2c_adapter_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_new_device.attr,
	&dev_attr_delete_device.attr,
	NULL
};
1075
ATTRIBUTE_GROUPS(i2c_adapter);
1076

1077
struct device_type i2c_adapter_type = {
1078
	.groups		= i2c_adapter_groups,
1079
	.release	= i2c_adapter_dev_release,
L
Linus Torvalds 已提交
1080
};
1081
EXPORT_SYMBOL_GPL(i2c_adapter_type);
L
Linus Torvalds 已提交
1082

1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
/**
 * 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);

1100 1101 1102 1103
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;
#endif

1104 1105 1106 1107
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
{
	struct i2c_devinfo	*devinfo;

1108
	down_read(&__i2c_board_lock);
1109 1110 1111 1112
	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
1113 1114
			dev_err(&adapter->dev,
				"Can't create device at 0x%02x\n",
1115 1116
				devinfo->board_info.addr);
	}
1117
	up_read(&__i2c_board_lock);
1118 1119
}

J
Jean Delvare 已提交
1120 1121
static int i2c_do_add_adapter(struct i2c_driver *driver,
			      struct i2c_adapter *adap)
1122
{
1123 1124 1125
	/* Detect supported devices on that bus, and instantiate them */
	i2c_detect(adap, driver);

1126 1127 1128
	return 0;
}

J
Jean Delvare 已提交
1129 1130 1131 1132 1133
static int __process_new_adapter(struct device_driver *d, void *data)
{
	return i2c_do_add_adapter(to_i2c_driver(d), data);
}

1134 1135 1136 1137 1138 1139
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,
};

1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 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
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);

1213
static int i2c_register_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1214
{
1215
	int res = -EINVAL;
L
Linus Torvalds 已提交
1216

1217
	/* Can't register until after driver model init */
1218
	if (WARN_ON(!is_registered)) {
1219 1220 1221
		res = -EAGAIN;
		goto out_list;
	}
1222

1223
	/* Sanity checks */
1224
	if (WARN(!adap->name[0], "i2c adapter has no name"))
1225
		goto out_list;
1226 1227

	if (!adap->algo) {
W
Wolfram Sang 已提交
1228
		pr_err("adapter '%s': no algo supplied!\n", adap->name);
1229
		goto out_list;
1230 1231
	}

1232 1233
	if (!adap->lock_ops)
		adap->lock_ops = &i2c_adapter_lock_ops;
1234

1235
	rt_mutex_init(&adap->bus_lock);
1236
	rt_mutex_init(&adap->mux_lock);
1237
	mutex_init(&adap->userspace_clients_lock);
1238
	INIT_LIST_HEAD(&adap->userspace_clients);
L
Linus Torvalds 已提交
1239

1240 1241 1242 1243
	/* Set default timeout to 1 second if not already set */
	if (adap->timeout == 0)
		adap->timeout = HZ;

1244 1245 1246 1247 1248 1249 1250 1251
	/* 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;
	}

1252
	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1253 1254
	adap->dev.bus = &i2c_bus_type;
	adap->dev.type = &i2c_adapter_type;
1255
	res = device_register(&adap->dev);
1256
	if (res) {
W
Wolfram Sang 已提交
1257
		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1258
		goto out_list;
1259
	}
L
Linus Torvalds 已提交
1260

1261 1262 1263 1264
	res = of_i2c_setup_smbus_alert(adap);
	if (res)
		goto out_reg;

1265 1266
	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

1267
	pm_runtime_no_callbacks(&adap->dev);
1268
	pm_suspend_ignore_children(&adap->dev, true);
1269
	pm_runtime_enable(&adap->dev);
1270

1271 1272 1273 1274 1275 1276 1277 1278
#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

1279
	i2c_init_recovery(adap);
1280

1281
	/* create pre-declared device nodes */
1282
	of_i2c_register_devices(adap);
1283 1284
	i2c_acpi_register_devices(adap);
	i2c_acpi_install_space_handler(adap);
1285

1286 1287 1288
	if (adap->nr < __i2c_first_dynamic_bus_num)
		i2c_scan_static_board_info(adap);

1289
	/* Notify drivers */
1290
	mutex_lock(&core_lock);
J
Jean Delvare 已提交
1291
	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
J
Jean Delvare 已提交
1292
	mutex_unlock(&core_lock);
1293 1294

	return 0;
1295

1296 1297 1298 1299
out_reg:
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);
1300
out_list:
1301
	mutex_lock(&core_lock);
1302
	idr_remove(&i2c_adapter_idr, adap->nr);
1303 1304
	mutex_unlock(&core_lock);
	return res;
L
Linus Torvalds 已提交
1305 1306
}

1307 1308 1309 1310 1311 1312 1313 1314 1315
/**
 * __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)
{
1316
	int id;
1317 1318

	mutex_lock(&core_lock);
1319
	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1320
	mutex_unlock(&core_lock);
1321
	if (WARN(id < 0, "couldn't get idr"))
1322 1323 1324 1325 1326
		return id == -ENOSPC ? -EBUSY : id;

	return i2c_register_adapter(adap);
}

1327 1328 1329
/**
 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
 * @adapter: the adapter to add
D
David Brownell 已提交
1330
 * Context: can sleep
1331 1332
 *
 * This routine is used to declare an I2C adapter when its bus number
1333 1334 1335
 * 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.
1336 1337 1338 1339 1340 1341 1342
 *
 * 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)
{
1343
	struct device *dev = &adapter->dev;
T
Tejun Heo 已提交
1344
	int id;
1345

1346 1347 1348 1349 1350 1351 1352 1353
	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
1354
	mutex_lock(&core_lock);
T
Tejun Heo 已提交
1355 1356
	id = idr_alloc(&i2c_adapter_idr, adapter,
		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
J
Jean Delvare 已提交
1357
	mutex_unlock(&core_lock);
1358
	if (WARN(id < 0, "couldn't get idr"))
T
Tejun Heo 已提交
1359
		return id;
1360 1361

	adapter->nr = id;
T
Tejun Heo 已提交
1362

1363 1364 1365 1366 1367 1368 1369
	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
1370
 * Context: can sleep
1371 1372
 *
 * This routine is used to declare an I2C adapter when its bus number
R
Randy Dunlap 已提交
1373 1374
 * 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
1375 1376
 * is used to properly configure I2C devices.
 *
1377 1378 1379
 * 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.
 *
1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391
 * 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)
{
1392 1393
	if (adap->nr == -1) /* -1 means dynamically assign bus id */
		return i2c_add_adapter(adap);
1394

1395
	return __i2c_add_numbered_adapter(adap);
1396 1397 1398
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);

L
Lars-Peter Clausen 已提交
1399
static void i2c_do_del_adapter(struct i2c_driver *driver,
J
Jean Delvare 已提交
1400
			      struct i2c_adapter *adapter)
1401
{
1402
	struct i2c_client *client, *_n;
1403

1404 1405
	/* Remove the devices we created ourselves as the result of hardware
	 * probing (using a driver's detect method) */
1406 1407 1408 1409 1410 1411 1412 1413
	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);
		}
	}
1414 1415
}

1416
static int __unregister_client(struct device *dev, void *dummy)
1417 1418 1419 1420 1421 1422 1423 1424
{
	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)
1425 1426
{
	struct i2c_client *client = i2c_verify_client(dev);
1427
	i2c_unregister_device(client);
1428 1429 1430
	return 0;
}

J
Jean Delvare 已提交
1431 1432
static int __process_removed_adapter(struct device_driver *d, void *data)
{
L
Lars-Peter Clausen 已提交
1433 1434
	i2c_do_del_adapter(to_i2c_driver(d), data);
	return 0;
J
Jean Delvare 已提交
1435 1436
}

D
David Brownell 已提交
1437 1438 1439 1440 1441 1442 1443 1444
/**
 * 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.
 */
1445
void i2c_del_adapter(struct i2c_adapter *adap)
L
Linus Torvalds 已提交
1446
{
1447
	struct i2c_adapter *found;
1448
	struct i2c_client *client, *next;
L
Linus Torvalds 已提交
1449 1450

	/* First make sure that this adapter was ever added */
1451 1452 1453 1454
	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
1455
		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1456
		return;
L
Linus Torvalds 已提交
1457 1458
	}

1459
	i2c_acpi_remove_space_handler(adap);
1460
	/* Tell drivers about this removal */
1461
	mutex_lock(&core_lock);
L
Lars-Peter Clausen 已提交
1462
	bus_for_each_drv(&i2c_bus_type, NULL, adap,
J
Jean Delvare 已提交
1463
			       __process_removed_adapter);
1464
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1465

1466
	/* Remove devices instantiated from sysfs */
1467 1468
	mutex_lock_nested(&adap->userspace_clients_lock,
			  i2c_adapter_depth(adap));
1469 1470 1471 1472 1473 1474
	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);
1475
	}
1476
	mutex_unlock(&adap->userspace_clients_lock);
1477

1478
	/* Detach any active clients. This can't fail, thus we do not
1479 1480 1481 1482
	 * 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
1483 1484
	device_for_each_child(&adap->dev, NULL, __unregister_client);
	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
L
Linus Torvalds 已提交
1485

1486 1487 1488 1489 1490
#ifdef CONFIG_I2C_COMPAT
	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
				 adap->dev.parent);
#endif

1491 1492 1493
	/* device name is gone after device_unregister */
	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);

1494 1495
	pm_runtime_disable(&adap->dev);

1496 1497
	i2c_host_notify_irq_teardown(adap);

1498 1499 1500 1501 1502
	/* 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
1503
	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1504
	 */
L
Linus Torvalds 已提交
1505 1506 1507 1508
	init_completion(&adap->dev_released);
	device_unregister(&adap->dev);
	wait_for_completion(&adap->dev_released);

1509
	/* free bus id */
1510
	mutex_lock(&core_lock);
L
Linus Torvalds 已提交
1511
	idr_remove(&i2c_adapter_idr, adap->nr);
1512
	mutex_unlock(&core_lock);
L
Linus Torvalds 已提交
1513

1514 1515 1516
	/* 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
1517
}
D
David Brownell 已提交
1518
EXPORT_SYMBOL(i2c_del_adapter);
L
Linus Torvalds 已提交
1519

1520 1521 1522 1523 1524 1525 1526 1527 1528 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
/**
 * 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;
1569 1570

	device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1571 1572 1573
}
EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);

D
David Brownell 已提交
1574 1575
/* ------------------------------------------------------------------------- */

J
Jean Delvare 已提交
1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587
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
1588
static int __process_new_driver(struct device *dev, void *data)
D
Dave Young 已提交
1589
{
1590 1591
	if (dev->type != &i2c_adapter_type)
		return 0;
J
Jean Delvare 已提交
1592
	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
D
Dave Young 已提交
1593 1594
}

D
David Brownell 已提交
1595 1596
/*
 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1597
 * i2c slave chips, on a bus instance associated with some i2c_adapter.
L
Linus Torvalds 已提交
1598 1599
 */

1600
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
L
Linus Torvalds 已提交
1601
{
1602
	int res;
L
Linus Torvalds 已提交
1603

1604
	/* Can't register until after driver model init */
1605
	if (WARN_ON(!is_registered))
1606 1607
		return -EAGAIN;

L
Linus Torvalds 已提交
1608
	/* add the driver to the list of i2c drivers in the driver core */
1609
	driver->driver.owner = owner;
L
Linus Torvalds 已提交
1610
	driver->driver.bus = &i2c_bus_type;
1611
	INIT_LIST_HEAD(&driver->clients);
L
Linus Torvalds 已提交
1612

1613
	/* When registration returns, the driver core
1614 1615
	 * will have called probe() for all matching-but-unbound devices.
	 */
L
Linus Torvalds 已提交
1616 1617
	res = driver_register(&driver->driver);
	if (res)
1618
		return res;
D
David Brownell 已提交
1619

W
Wolfram Sang 已提交
1620
	pr_debug("driver [%s] registered\n", driver->driver.name);
L
Linus Torvalds 已提交
1621

1622
	/* Walk the adapters that are already present */
J
Jean Delvare 已提交
1623
	i2c_for_each_dev(driver, __process_new_driver);
1624

D
Dave Young 已提交
1625 1626 1627 1628
	return 0;
}
EXPORT_SYMBOL(i2c_register_driver);

J
Jean Delvare 已提交
1629
static int __process_removed_driver(struct device *dev, void *data)
D
Dave Young 已提交
1630
{
L
Lars-Peter Clausen 已提交
1631 1632 1633
	if (dev->type == &i2c_adapter_type)
		i2c_do_del_adapter(data, to_i2c_adapter(dev));
	return 0;
L
Linus Torvalds 已提交
1634 1635
}

D
David Brownell 已提交
1636 1637 1638
/**
 * i2c_del_driver - unregister I2C driver
 * @driver: the driver being unregistered
D
David Brownell 已提交
1639
 * Context: can sleep
D
David Brownell 已提交
1640
 */
1641
void i2c_del_driver(struct i2c_driver *driver)
L
Linus Torvalds 已提交
1642
{
J
Jean Delvare 已提交
1643
	i2c_for_each_dev(driver, __process_removed_driver);
L
Linus Torvalds 已提交
1644 1645

	driver_unregister(&driver->driver);
W
Wolfram Sang 已提交
1646
	pr_debug("driver [%s] unregistered\n", driver->driver.name);
L
Linus Torvalds 已提交
1647
}
D
David Brownell 已提交
1648
EXPORT_SYMBOL(i2c_del_driver);
L
Linus Torvalds 已提交
1649

D
David Brownell 已提交
1650 1651
/* ------------------------------------------------------------------------- */

1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
/**
 * 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
1664
{
1665 1666 1667
	if (client && get_device(&client->dev))
		return client;
	return NULL;
L
Linus Torvalds 已提交
1668
}
D
David Brownell 已提交
1669
EXPORT_SYMBOL(i2c_use_client);
L
Linus Torvalds 已提交
1670

1671 1672 1673 1674 1675 1676 1677
/**
 * 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
1678
{
1679 1680
	if (client)
		put_device(&client->dev);
L
Linus Torvalds 已提交
1681
}
D
David Brownell 已提交
1682
EXPORT_SYMBOL(i2c_release_client);
L
Linus Torvalds 已提交
1683

1684 1685 1686 1687 1688 1689 1690 1691 1692
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;
1693 1694 1695 1696
	struct i2c_driver	*driver;

	if (!client || !client->dev.driver)
		return 0;
1697

1698 1699 1700
	driver = to_i2c_driver(client->dev.driver);
	if (driver->command)
		driver->command(client, arg->cmd, arg->arg);
1701 1702 1703
	return 0;
}

L
Linus Torvalds 已提交
1704 1705
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
{
1706
	struct i2c_cmd_arg	cmd_arg;
L
Linus Torvalds 已提交
1707

1708 1709 1710
	cmd_arg.cmd = cmd;
	cmd_arg.arg = arg;
	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
L
Linus Torvalds 已提交
1711
}
D
David Brownell 已提交
1712
EXPORT_SYMBOL(i2c_clients_command);
L
Linus Torvalds 已提交
1713 1714 1715 1716 1717

static int __init i2c_init(void)
{
	int retval;

1718 1719 1720 1721 1722 1723 1724
	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
1725 1726 1727
	retval = bus_register(&i2c_bus_type);
	if (retval)
		return retval;
1728 1729 1730

	is_registered = true;

1731 1732 1733 1734 1735 1736 1737
#ifdef CONFIG_I2C_COMPAT
	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
	if (!i2c_adapter_compat_class) {
		retval = -ENOMEM;
		goto bus_err;
	}
#endif
1738 1739
	retval = i2c_add_driver(&dummy_driver);
	if (retval)
1740
		goto class_err;
1741 1742 1743

	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1744 1745
	if (IS_ENABLED(CONFIG_ACPI))
		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1746

1747 1748
	return 0;

1749 1750 1751
class_err:
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
1752
bus_err:
1753
#endif
1754
	is_registered = false;
1755 1756
	bus_unregister(&i2c_bus_type);
	return retval;
L
Linus Torvalds 已提交
1757 1758 1759 1760
}

static void __exit i2c_exit(void)
{
1761 1762
	if (IS_ENABLED(CONFIG_ACPI))
		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1763 1764
	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1765
	i2c_del_driver(&dummy_driver);
1766 1767 1768
#ifdef CONFIG_I2C_COMPAT
	class_compat_unregister(i2c_adapter_compat_class);
#endif
L
Linus Torvalds 已提交
1769
	bus_unregister(&i2c_bus_type);
1770
	tracepoint_synchronize_unregister();
L
Linus Torvalds 已提交
1771 1772
}

D
David Brownell 已提交
1773 1774 1775 1776
/* 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
1777 1778 1779 1780 1781 1782 1783
module_exit(i2c_exit);

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

W
Wolfram Sang 已提交
1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 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
/* 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");
1834 1835 1836

			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
1837 1838 1839
		} else {
			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
				return i2c_quirk_error(adap, &msgs[i], "msg too long");
1840 1841 1842

			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
1843 1844 1845 1846 1847 1848
		}
	}

	return 0;
}

1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865
/**
 * __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;

1866 1867 1868
	if (WARN_ON(!msgs || num < 1))
		return -EINVAL;

W
Wolfram Sang 已提交
1869 1870 1871
	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
		return -EOPNOTSUPP;

1872 1873
	/*
	 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1874 1875 1876
	 * enabled.  This is an efficient way of keeping the for-loop from
	 * being executed when not needed.
	 */
1877
	if (static_branch_unlikely(&i2c_trace_msg_key)) {
1878 1879 1880 1881 1882 1883 1884 1885
		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);
	}

1886 1887 1888 1889 1890 1891 1892 1893 1894 1895
	/* 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;
	}

1896
	if (static_branch_unlikely(&i2c_trace_msg_key)) {
1897 1898 1899 1900
		int i;
		for (i = 0; i < ret; i++)
			if (msgs[i].flags & I2C_M_RD)
				trace_i2c_reply(adap, &msgs[i], i);
1901
		trace_i2c_result(adap, num, ret);
1902 1903
	}

1904 1905 1906 1907
	return ret;
}
EXPORT_SYMBOL(__i2c_transfer);

1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919
/**
 * 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
1920
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
L
Linus Torvalds 已提交
1921
{
1922
	int ret;
L
Linus Torvalds 已提交
1923

1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940
	/* 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
1941 1942 1943
	if (adap->algo->master_xfer) {
#ifdef DEBUG
		for (ret = 0; ret < num; ret++) {
1944 1945 1946 1947
			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,
1948
				(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
L
Linus Torvalds 已提交
1949 1950 1951
		}
#endif

1952
		if (in_atomic() || irqs_disabled()) {
1953
			ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1954 1955 1956 1957
			if (!ret)
				/* I2C activity is ongoing. */
				return -EAGAIN;
		} else {
1958
			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1959 1960
		}

1961
		ret = __i2c_transfer(adap, msgs, num);
1962
		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
L
Linus Torvalds 已提交
1963 1964 1965 1966

		return ret;
	} else {
		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
D
David Brownell 已提交
1967
		return -EOPNOTSUPP;
L
Linus Torvalds 已提交
1968 1969
	}
}
D
David Brownell 已提交
1970
EXPORT_SYMBOL(i2c_transfer);
L
Linus Torvalds 已提交
1971

1972
/**
1973 1974
 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
 *			       to/from a buffer
1975
 * @client: Handle to slave device
1976 1977 1978
 * @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
1979
 *
1980
 * Returns negative errno, or else the number of bytes transferred.
1981
 */
1982 1983
int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
			      int count, u16 flags)
L
Linus Torvalds 已提交
1984 1985
{
	int ret;
1986 1987 1988 1989 1990 1991
	struct i2c_msg msg = {
		.addr = client->addr,
		.flags = flags | (client->flags & I2C_M_TEN),
		.len = count,
		.buf = buf,
	};
1992

1993
	ret = i2c_transfer(client->adapter, &msg, 1);
1994

1995
	/*
1996 1997
	 * If everything went ok (i.e. 1 msg transferred), return #bytes
	 * transferred, else error code.
1998
	 */
1999
	return (ret == 1) ? count : ret;
L
Linus Torvalds 已提交
2000
}
2001
EXPORT_SYMBOL(i2c_transfer_buffer_flags);
L
Linus Torvalds 已提交
2002

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033
/**
 * 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
2034 2035 2036 2037 2038 2039
/* ----------------------------------------------------
 * the i2c address scanning function
 * Will not work for 10-bit addresses!
 * ----------------------------------------------------
 */

2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063
/*
 * 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
2064 2065
	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2066 2067
		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
				     I2C_SMBUS_QUICK, NULL);
2068 2069 2070 2071
	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 {
2072 2073
		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
			 addr);
2074 2075
		err = -EOPNOTSUPP;
	}
2076 2077 2078 2079

	return err >= 0;
}

J
Jean Delvare 已提交
2080
static int i2c_detect_address(struct i2c_client *temp_client,
2081 2082 2083 2084 2085 2086 2087 2088
			      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 */
2089
	err = i2c_check_7bit_addr_validity_strict(addr);
2090
	if (err) {
2091 2092
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
			 addr);
2093
		return err;
2094 2095
	}

2096
	/* Skip if already in use (7 bit, no need to encode flags) */
2097
	if (i2c_check_addr_busy(adapter, addr))
2098 2099
		return 0;

J
Jean Delvare 已提交
2100
	/* Make sure there is something at this address */
2101 2102
	if (!i2c_default_probe(adapter, addr))
		return 0;
2103 2104 2105 2106

	/* Finally call the custom detection function */
	memset(&info, 0, sizeof(struct i2c_board_info));
	info.addr = addr;
2107
	err = driver->detect(temp_client, &info);
2108 2109 2110 2111 2112 2113 2114 2115
	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') {
2116 2117 2118
		dev_err(&adapter->dev,
			"%s detection function provided no name for 0x%x\n",
			driver->driver.name, addr);
2119 2120 2121 2122
	} else {
		struct i2c_client *client;

		/* Detection succeeded, instantiate the device */
2123 2124 2125 2126 2127 2128 2129
		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);

2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143
		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)
{
2144
	const unsigned short *address_list;
2145 2146 2147 2148
	struct i2c_client *temp_client;
	int i, err = 0;
	int adap_id = i2c_adapter_id(adapter);

2149 2150
	address_list = driver->address_list;
	if (!driver->detect || !address_list)
2151 2152
		return 0;

2153 2154 2155
	/* Warn that the adapter lost class based instantiation */
	if (adapter->class == I2C_CLASS_DEPRECATED) {
		dev_dbg(&adapter->dev,
2156 2157
			"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",
2158 2159 2160 2161
			driver->driver.name);
		return 0;
	}

J
Jean Delvare 已提交
2162 2163 2164 2165
	/* Stop here if the classes do not match */
	if (!(adapter->class & driver->class))
		return 0;

2166 2167 2168 2169 2170 2171
	/* 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;

2172
	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2173 2174 2175
		dev_dbg(&adapter->dev,
			"found normal entry for adapter %d, addr 0x%02x\n",
			adap_id, address_list[i]);
2176
		temp_client->addr = address_list[i];
J
Jean Delvare 已提交
2177
		err = i2c_detect_address(temp_client, driver);
J
Jean Delvare 已提交
2178 2179
		if (unlikely(err))
			break;
2180 2181 2182 2183 2184 2185
	}

	kfree(temp_client);
	return err;
}

2186 2187 2188 2189 2190 2191 2192
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
2193 2194 2195
struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
		      struct i2c_board_info *info,
2196 2197
		      unsigned short const *addr_list,
		      int (*probe)(struct i2c_adapter *, unsigned short addr))
J
Jean Delvare 已提交
2198 2199 2200
{
	int i;

2201
	if (!probe)
2202
		probe = i2c_default_probe;
J
Jean Delvare 已提交
2203 2204 2205

	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
		/* Check address validity */
2206
		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2207 2208
			dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
				 addr_list[i]);
J
Jean Delvare 已提交
2209 2210 2211
			continue;
		}

2212
		/* Check address availability (7 bit, no need to encode flags) */
2213
		if (i2c_check_addr_busy(adap, addr_list[i])) {
2214 2215 2216
			dev_dbg(&adap->dev,
				"Address 0x%02x already in use, not probing\n",
				addr_list[i]);
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2217 2218 2219
			continue;
		}

2220
		/* Test address responsiveness */
2221
		if (probe(adap, addr_list[i]))
2222
			break;
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2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234
	}

	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);

2235
struct i2c_adapter *i2c_get_adapter(int nr)
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Linus Torvalds 已提交
2236 2237
{
	struct i2c_adapter *adapter;
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2238

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2239
	mutex_lock(&core_lock);
2240
	adapter = idr_find(&i2c_adapter_idr, nr);
2241 2242 2243 2244 2245 2246
	if (!adapter)
		goto exit;

	if (try_module_get(adapter->owner))
		get_device(&adapter->dev);
	else
2247 2248
		adapter = NULL;

2249
 exit:
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2250
	mutex_unlock(&core_lock);
2251
	return adapter;
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2252
}
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2253
EXPORT_SYMBOL(i2c_get_adapter);
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2254 2255 2256

void i2c_put_adapter(struct i2c_adapter *adap)
{
2257 2258 2259 2260 2261
	if (!adap)
		return;

	put_device(&adap->dev);
	module_put(adap->owner);
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2262
}
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2263
EXPORT_SYMBOL(i2c_put_adapter);
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2264

2265 2266 2267 2268 2269 2270 2271
/**
 * 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
2272
 *	   calling i2c_put_dma_safe_msg_buf().
2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294
 *
 * 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);

/**
2295
 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2296
 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2297 2298
 * @msg: the message which the buffer corresponds to
 * @xferred: bool saying if the message was transferred
2299
 */
2300
void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2301 2302 2303 2304
{
	if (!buf || buf == msg->buf)
		return;

2305
	if (xferred && msg->flags & I2C_M_RD)
2306 2307 2308 2309
		memcpy(msg->buf, buf, msg->len);

	kfree(buf);
}
2310
EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2311

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Linus Torvalds 已提交
2312 2313 2314
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus main module");
MODULE_LICENSE("GPL");