linux/drivers/i2c/i2c-smbus.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * i2c-smbus.c - SMBus extensions to the I2C protocol
 *
 * Copyright (C) 2008 David Brownell
 * Copyright (C) 2010-2019 Jean Delvare <[email protected]>
 */

#include <linux/device.h>
#include <linux/dmi.h>
#include <linux/i2c.h>
#include <linux/i2c-smbus.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

struct i2c_smbus_alert { … };

struct alert_data { … };

/* If this is the alerting device, notify its driver */
static int smbus_do_alert(struct device *dev, void *addrp)
{ … }

/*
 * The alert IRQ handler needs to hand work off to a task which can issue
 * SMBus calls, because those sleeping calls can't be made in IRQ context.
 */
static irqreturn_t smbus_alert(int irq, void *d)
{ … }

static void smbalert_work(struct work_struct *work)
{ … }

/* Setup SMBALERT# infrastructure */
static int smbalert_probe(struct i2c_client *ara)
{ … }

/* IRQ and memory resources are managed so they are freed automatically */
static void smbalert_remove(struct i2c_client *ara)
{ … }

static const struct i2c_device_id smbalert_ids[] = …;
MODULE_DEVICE_TABLE(i2c, smbalert_ids);

static struct i2c_driver smbalert_driver = …;

/**
 * i2c_handle_smbus_alert - Handle an SMBus alert
 * @ara: the ARA client on the relevant adapter
 * Context: can't sleep
 *
 * Helper function to be called from an I2C bus driver's interrupt
 * handler. It will schedule the alert work, in turn calling the
 * corresponding I2C device driver's alert function.
 *
 * It is assumed that ara is a valid i2c client previously returned by
 * i2c_new_smbus_alert_device().
 */
int i2c_handle_smbus_alert(struct i2c_client *ara)
{ … }
EXPORT_SYMBOL_GPL(…);

module_i2c_driver(…) …;

#if IS_ENABLED(CONFIG_I2C_SLAVE)
#define SMBUS_HOST_NOTIFY_LEN …
struct i2c_slave_host_notify_status { … };

static int i2c_slave_host_notify_cb(struct i2c_client *client,
				    enum i2c_slave_event event, u8 *val)
{ … }

/**
 * i2c_new_slave_host_notify_device - get a client for SMBus host-notify support
 * @adapter: the target adapter
 * Context: can sleep
 *
 * Setup handling of the SMBus host-notify protocol on a given I2C bus segment.
 *
 * Handling is done by creating a device and its callback and handling data
 * received via the SMBus host-notify address (0x8)
 *
 * This returns the client, which should be ultimately freed using
 * i2c_free_slave_host_notify_device(); or an ERRPTR to indicate an error.
 */
struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * i2c_free_slave_host_notify_device - free the client for SMBus host-notify
 * support
 * @client: the client to free
 * Context: can sleep
 *
 * Free the i2c_client allocated via i2c_new_slave_host_notify_device
 */
void i2c_free_slave_host_notify_device(struct i2c_client *client)
{ … }
EXPORT_SYMBOL_GPL(…);
#endif

/*
 * SPD is not part of SMBus but we include it here for convenience as the
 * target systems are the same.
 * Restrictions to automatic SPD instantiation:
 *  - Only works if all filled slots have the same memory type
 *  - Only works for (LP)DDR memory types up to DDR5
 *  - Only works on systems with 1 to 8 memory slots
 */
#if IS_ENABLED(CONFIG_DMI)
void i2c_register_spd(struct i2c_adapter *adap)
{ … }
EXPORT_SYMBOL_GPL(…);
#endif

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;