/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
/*
* i2c.h - definitions for the I2C bus interface
*
* Copyright (C) 1995-2000 Simon G. Vogl
* With some changes from Kyösti Mälkki <[email protected]> and
* Frodo Looijaard <[email protected]>
*/
#ifndef _UAPI_LINUX_I2C_H
#define _UAPI_LINUX_I2C_H
#include <linux/types.h>
/**
* struct i2c_msg - an I2C transaction segment beginning with START
*
* @addr: Slave address, either 7 or 10 bits. When this is a 10 bit address,
* %I2C_M_TEN must be set in @flags and the adapter must support
* %I2C_FUNC_10BIT_ADDR.
*
* @flags:
* Supported by all adapters:
* %I2C_M_RD: read data (from slave to master). Guaranteed to be 0x0001!
*
* Optional:
* %I2C_M_DMA_SAFE: the buffer of this message is DMA safe. Makes only sense
* in kernelspace, because userspace buffers are copied anyway
*
* Only if I2C_FUNC_10BIT_ADDR is set:
* %I2C_M_TEN: this is a 10 bit chip address
*
* Only if I2C_FUNC_SMBUS_READ_BLOCK_DATA is set:
* %I2C_M_RECV_LEN: message length will be first received byte
*
* Only if I2C_FUNC_NOSTART is set:
* %I2C_M_NOSTART: skip repeated start sequence
* Only if I2C_FUNC_PROTOCOL_MANGLING is set:
* %I2C_M_NO_RD_ACK: in a read message, master ACK/NACK bit is skipped
* %I2C_M_IGNORE_NAK: treat NACK from client as ACK
* %I2C_M_REV_DIR_ADDR: toggles the Rd/Wr bit
* %I2C_M_STOP: force a STOP condition after the message
*
* @len: Number of data bytes in @buf being read from or written to the I2C
* slave address. For read transactions where %I2C_M_RECV_LEN is set, the
* caller guarantees that this buffer can hold up to %I2C_SMBUS_BLOCK_MAX
* bytes in addition to the initial length byte sent by the slave (plus,
* if used, the SMBus PEC); and this value will be incremented by the number
* of block data bytes received.
*
* @buf: The buffer into which data is read, or from which it's written.
*
* An i2c_msg is the low level representation of one segment of an I2C
* transaction. It is visible to drivers in the @i2c_transfer() procedure,
* to userspace from i2c-dev, and to I2C adapter drivers through the
* @i2c_adapter.@master_xfer() method.
*
* Except when I2C "protocol mangling" is used, all I2C adapters implement
* the standard rules for I2C transactions. Each transaction begins with a
* START. That is followed by the slave address, and a bit encoding read
* versus write. Then follow all the data bytes, possibly including a byte
* with SMBus PEC. The transfer terminates with a NAK, or when all those
* bytes have been transferred and ACKed. If this is the last message in a
* group, it is followed by a STOP. Otherwise it is followed by the next
* @i2c_msg transaction segment, beginning with a (repeated) START.
*
* Alternatively, when the adapter supports %I2C_FUNC_PROTOCOL_MANGLING then
* passing certain @flags may have changed those standard protocol behaviors.
* Those flags are only for use with broken/nonconforming slaves, and with
* adapters which are known to support the specific mangling options they need.
*/
struct i2c_msg {
__u16 addr;
__u16 flags;
#define I2C_M_RD 0x0001 /* guaranteed to be 0x0001! */
#define I2C_M_TEN 0x0010 /* use only if I2C_FUNC_10BIT_ADDR */
#define I2C_M_DMA_SAFE 0x0200 /* use only in kernel space */
#define I2C_M_RECV_LEN 0x0400 /* use only if I2C_FUNC_SMBUS_READ_BLOCK_DATA */
#define I2C_M_NO_RD_ACK 0x0800 /* use only if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_IGNORE_NAK 0x1000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_REV_DIR_ADDR 0x2000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_NOSTART 0x4000 /* use only if I2C_FUNC_NOSTART */
#define I2C_M_STOP 0x8000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */
__u16 len;
__u8 *buf;
};
/* To determine what functionality is present */
#define I2C_FUNC_I2C 0x00000001
#define I2C_FUNC_10BIT_ADDR 0x00000002 /* required for I2C_M_TEN */
#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* required for I2C_M_IGNORE_NAK etc. */
#define I2C_FUNC_SMBUS_PEC 0x00000008
#define I2C_FUNC_NOSTART 0x00000010 /* required for I2C_M_NOSTART */
#define I2C_FUNC_SLAVE 0x00000020
#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 or later */
#define I2C_FUNC_SMBUS_QUICK 0x00010000
#define I2C_FUNC_SMBUS_READ_BYTE 0x00020000
#define I2C_FUNC_SMBUS_WRITE_BYTE 0x00040000
#define I2C_FUNC_SMBUS_READ_BYTE_DATA 0x00080000
#define I2C_FUNC_SMBUS_WRITE_BYTE_DATA 0x00100000
#define I2C_FUNC_SMBUS_READ_WORD_DATA 0x00200000
#define I2C_FUNC_SMBUS_WRITE_WORD_DATA 0x00400000
#define I2C_FUNC_SMBUS_PROC_CALL 0x00800000
#define I2C_FUNC_SMBUS_READ_BLOCK_DATA 0x01000000 /* required for I2C_M_RECV_LEN */
#define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000
#define I2C_FUNC_SMBUS_READ_I2C_BLOCK 0x04000000 /* I2C-like block xfer */
#define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK 0x08000000 /* w/ 1-byte reg. addr. */
#define I2C_FUNC_SMBUS_HOST_NOTIFY 0x10000000 /* SMBus 2.0 or later */
#define I2C_FUNC_SMBUS_BYTE (I2C_FUNC_SMBUS_READ_BYTE | \
I2C_FUNC_SMBUS_WRITE_BYTE)
#define I2C_FUNC_SMBUS_BYTE_DATA (I2C_FUNC_SMBUS_READ_BYTE_DATA | \
I2C_FUNC_SMBUS_WRITE_BYTE_DATA)
#define I2C_FUNC_SMBUS_WORD_DATA (I2C_FUNC_SMBUS_READ_WORD_DATA | \
I2C_FUNC_SMBUS_WRITE_WORD_DATA)
#define I2C_FUNC_SMBUS_BLOCK_DATA (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \
I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)
#define I2C_FUNC_SMBUS_I2C_BLOCK (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \
I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)
#define I2C_FUNC_SMBUS_EMUL (I2C_FUNC_SMBUS_QUICK | \
I2C_FUNC_SMBUS_BYTE | \
I2C_FUNC_SMBUS_BYTE_DATA | \
I2C_FUNC_SMBUS_WORD_DATA | \
I2C_FUNC_SMBUS_PROC_CALL | \
I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \
I2C_FUNC_SMBUS_I2C_BLOCK | \
I2C_FUNC_SMBUS_PEC)
/* if I2C_M_RECV_LEN is also supported */
#define I2C_FUNC_SMBUS_EMUL_ALL (I2C_FUNC_SMBUS_EMUL | \
I2C_FUNC_SMBUS_READ_BLOCK_DATA | \
I2C_FUNC_SMBUS_BLOCK_PROC_CALL)
/*
* Data for SMBus Messages
*/
#define I2C_SMBUS_BLOCK_MAX 32 /* As specified in SMBus standard */
union i2c_smbus_data {
__u8 byte;
__u16 word;
__u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
/* and one more for user-space compatibility */
};
/* i2c_smbus_xfer read or write markers */
#define I2C_SMBUS_READ 1
#define I2C_SMBUS_WRITE 0
/* SMBus transaction types (size parameter in the above functions)
Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
#define I2C_SMBUS_QUICK 0
#define I2C_SMBUS_BYTE 1
#define I2C_SMBUS_BYTE_DATA 2
#define I2C_SMBUS_WORD_DATA 3
#define I2C_SMBUS_PROC_CALL 4
#define I2C_SMBUS_BLOCK_DATA 5
#define I2C_SMBUS_I2C_BLOCK_BROKEN 6
#define I2C_SMBUS_BLOCK_PROC_CALL 7 /* SMBus 2.0 */
#define I2C_SMBUS_I2C_BLOCK_DATA 8
#endif /* _UAPI_LINUX_I2C_H */
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