path: root/include/linux/i2c.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * i2c.h - definitions for the Linux i2c bus interface
 * Copyright (C) 1995-2000 Simon G. Vogl
 * Copyright (C) 2013-2019 Wolfram Sang <wsa@kernel.org>
 *
 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
 * Frodo Looijaard <frodol@dds.nl>
 */
#ifndef _LINUX_I2C_H
#define _LINUX_I2C_H

#include <linux/acpi.h>		/* for acpi_handle */
#include <linux/bits.h>
#include <linux/mod_devicetable.h>
#include <linux/device.h>	/* for struct device */
#include <linux/sched.h>	/* for completion */
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/rtmutex.h>
#include <linux/irqdomain.h>		/* for Host Notify IRQ */
#include <linux/of.h>		/* for struct device_node */
#include <linux/swab.h>		/* for swab16 */
#include <uapi/linux/i2c.h>

extern const struct bus_type i2c_bus_type;
extern const struct device_type i2c_adapter_type;
extern const struct device_type i2c_client_type;

/* --- General options ------------------------------------------------	*/

struct i2c_msg;
struct i2c_adapter;
struct i2c_client;
struct i2c_driver;
struct i2c_device_identity;
union i2c_smbus_data;
struct i2c_board_info;
enum i2c_slave_event;
typedef int (*i2c_slave_cb_t)(struct i2c_client *client,
			      enum i2c_slave_event event, u8 *val);

/* I2C Frequency Modes */
#define I2C_MAX_STANDARD_MODE_FREQ	100000
#define I2C_MAX_FAST_MODE_FREQ		400000
#define I2C_MAX_FAST_MODE_PLUS_FREQ	1000000
#define I2C_MAX_TURBO_MODE_FREQ		1400000
#define I2C_MAX_HIGH_SPEED_MODE_FREQ	3400000
#define I2C_MAX_ULTRA_FAST_MODE_FREQ	5000000

struct module;
struct property_entry;

#if IS_ENABLED(CONFIG_I2C)
/* Return the Frequency mode string based on the bus frequency */
const char *i2c_freq_mode_string(u32 bus_freq_hz);

/*
 * The master routines are the ones normally used to transmit data to devices
 * on a bus (or read from them). Apart from two basic transfer functions to
 * transmit one message at a time, a more complex version can be used to
 * transmit an arbitrary number of messages without interruption.
 * @count must be less than 64k since msg.len is u16.
 */
int i2c_transfer_buffer_flags(const struct i2c_client *client,
			      char *buf, int count, u16 flags);

/**
 * i2c_master_recv - issue a single I2C message in master receive mode
 * @client: Handle to slave device
 * @buf: Where to store data read from slave
 * @count: How many bytes to read, must be less than 64k since msg.len is u16
 *
 * Returns negative errno, or else the number of bytes read.
 */
static inline int i2c_master_recv(const struct i2c_client *client,
				  char *buf, int count)
{
	return i2c_transfer_buffer_flags(client, buf, count, I2C_M_RD);
};

/**
 * i2c_master_recv_dmasafe - issue a single I2C message in master receive mode
 *			     using a DMA safe buffer
 * @client: Handle to slave device
 * @buf: Where to store data read from slave, must be safe to use with DMA
 * @count: How many bytes to read, must be less than 64k since msg.len is u16
 *
 * Returns negative errno, or else the number of bytes read.
 */
static inline int i2c_master_recv_dmasafe(const struct i2c_client *client,
					  char *buf, int count)
{
	return i2c_transfer_buffer_flags(client, buf, count,
					 I2C_M_RD | I2C_M_DMA_SAFE);
};

/**
 * i2c_master_send - issue a single I2C message in master transmit mode
 * @client: Handle to slave device
 * @buf: Data that will be written to the slave
 * @count: How many bytes to write, must be less than 64k since msg.len is u16
 *
 * Returns negative errno, or else the number of bytes written.
 */
static inline int i2c_master_send(const struct i2c_client *client,
				  const char *buf, int count)
{
	return i2c_transfer_buffer_flags(client, (char *)buf, count, 0);
};

/**
 * i2c_master_send_dmasafe - issue a single I2C message in master transmit mode
 *			     using a DMA safe buffer
 * @client: Handle to slave device
 * @buf: Data that will be written to the slave, must be safe to use with DMA
 * @count: How many bytes to write, must be less than 64k since msg.len is u16
 *
 * Returns negative errno, or else the number of bytes written.
 */
static inline int i2c_master_send_dmasafe(const struct i2c_client *client,
					  const char *buf, int count)
{
	return i2c_transfer_buffer_flags(client, (char *)buf, count,
					 I2C_M_DMA_SAFE);
};

/* Transfer num messages.
 */
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
/* Unlocked flavor */
int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);

/* This is the very generalized SMBus access routine. You probably do not
   want to use this, though; one of the functions below may be much easier,
   and probably just as fast.
   Note that we use i2c_adapter here, because you do not need a specific
   smbus adapter to call this function. */
s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
		   unsigned short flags,