1/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ 2/* ------------------------------------------------------------------------- */ 3/* */ 4/* i2c.h - definitions for the i2c-bus interface */ 5/* */ 6/* ------------------------------------------------------------------------- */ 7/* Copyright (C) 1995-2000 Simon G. Vogl 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 2 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 22 MA 02110-1301 USA. */ 23/* ------------------------------------------------------------------------- */ 24 25/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and 26 Frodo Looijaard <frodol@dds.nl> */ 27 28#ifndef _UAPI_LINUX_I2C_H 29#define _UAPI_LINUX_I2C_H 30 31#include <linux/types.h> 32 33/** 34 * struct i2c_msg - an I2C transaction segment beginning with START 35 * @addr: Slave address, either seven or ten bits. When this is a ten 36 * bit address, I2C_M_TEN must be set in @flags and the adapter 37 * must support I2C_FUNC_10BIT_ADDR. 38 * @flags: I2C_M_RD is handled by all adapters. No other flags may be 39 * provided unless the adapter exported the relevant I2C_FUNC_* 40 * flags through i2c_check_functionality(). 41 * @len: Number of data bytes in @buf being read from or written to the 42 * I2C slave address. For read transactions where I2C_M_RECV_LEN 43 * is set, the caller guarantees that this buffer can hold up to 44 * 32 bytes in addition to the initial length byte sent by the 45 * slave (plus, if used, the SMBus PEC); and this value will be 46 * incremented by the number of block data bytes received. 47 * @buf: The buffer into which data is read, or from which it's written. 48 * 49 * An i2c_msg is the low level representation of one segment of an I2C 50 * transaction. It is visible to drivers in the @i2c_transfer() procedure, 51 * to userspace from i2c-dev, and to I2C adapter drivers through the 52 * @i2c_adapter.@master_xfer() method. 53 * 54 * Except when I2C "protocol mangling" is used, all I2C adapters implement 55 * the standard rules for I2C transactions. Each transaction begins with a 56 * START. That is followed by the slave address, and a bit encoding read 57 * versus write. Then follow all the data bytes, possibly including a byte 58 * with SMBus PEC. The transfer terminates with a NAK, or when all those 59 * bytes have been transferred and ACKed. If this is the last message in a 60 * group, it is followed by a STOP. Otherwise it is followed by the next 61 * @i2c_msg transaction segment, beginning with a (repeated) START. 62 * 63 * Alternatively, when the adapter supports I2C_FUNC_PROTOCOL_MANGLING then 64 * passing certain @flags may have changed those standard protocol behaviors. 65 * Those flags are only for use with broken/nonconforming slaves, and with 66 * adapters which are known to support the specific mangling options they 67 * need (one or more of IGNORE_NAK, NO_RD_ACK, NOSTART, and REV_DIR_ADDR). 68 */ 69struct i2c_msg { 70 __u16 addr; /* slave address */ 71 __u16 flags; 72#define I2C_M_RD 0x0001 /* read data, from slave to master */ 73 /* I2C_M_RD is guaranteed to be 0x0001! */ 74#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */ 75#define I2C_M_DMA_SAFE 0x0200 /* the buffer of this message is DMA safe */ 76 /* makes only sense in kernelspace */ 77 /* userspace buffers are copied anyway */ 78#define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */ 79#define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */ 80#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */ 81#define I2C_M_REV_DIR_ADDR 0x2000 /* if I2C_FUNC_PROTOCOL_MANGLING */ 82#define I2C_M_NOSTART 0x4000 /* if I2C_FUNC_NOSTART */ 83#define I2C_M_STOP 0x8000 /* if I2C_FUNC_PROTOCOL_MANGLING */ 84 __u16 len; /* msg length */ 85 __u8 *buf; /* pointer to msg data */ 86}; 87 88/* To determine what functionality is present */ 89 90#define I2C_FUNC_I2C 0x00000001 91#define I2C_FUNC_10BIT_ADDR 0x00000002 92#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* I2C_M_IGNORE_NAK etc. */ 93#define I2C_FUNC_SMBUS_PEC 0x00000008 94#define I2C_FUNC_NOSTART 0x00000010 /* I2C_M_NOSTART */ 95#define I2C_FUNC_SLAVE 0x00000020 96#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 */ 97#define I2C_FUNC_SMBUS_QUICK 0x00010000 98#define I2C_FUNC_SMBUS_READ_BYTE 0x00020000 99#define I2C_FUNC_SMBUS_WRITE_BYTE 0x00040000 100#define I2C_FUNC_SMBUS_READ_BYTE_DATA 0x00080000 101#define I2C_FUNC_SMBUS_WRITE_BYTE_DATA 0x00100000 102#define I2C_FUNC_SMBUS_READ_WORD_DATA 0x00200000 103#define I2C_FUNC_SMBUS_WRITE_WORD_DATA 0x00400000 104#define I2C_FUNC_SMBUS_PROC_CALL 0x00800000 105#define I2C_FUNC_SMBUS_READ_BLOCK_DATA 0x01000000 106#define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000 107#define I2C_FUNC_SMBUS_READ_I2C_BLOCK 0x04000000 /* I2C-like block xfer */ 108#define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK 0x08000000 /* w/ 1-byte reg. addr. */ 109#define I2C_FUNC_SMBUS_HOST_NOTIFY 0x10000000 110 111#define I2C_FUNC_SMBUS_BYTE (I2C_FUNC_SMBUS_READ_BYTE | \ 112 I2C_FUNC_SMBUS_WRITE_BYTE) 113#define I2C_FUNC_SMBUS_BYTE_DATA (I2C_FUNC_SMBUS_READ_BYTE_DATA | \ 114 I2C_FUNC_SMBUS_WRITE_BYTE_DATA) 115#define I2C_FUNC_SMBUS_WORD_DATA (I2C_FUNC_SMBUS_READ_WORD_DATA | \ 116 I2C_FUNC_SMBUS_WRITE_WORD_DATA) 117#define I2C_FUNC_SMBUS_BLOCK_DATA (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \ 118 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) 119#define I2C_FUNC_SMBUS_I2C_BLOCK (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \ 120 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK) 121 122#define I2C_FUNC_SMBUS_EMUL (I2C_FUNC_SMBUS_QUICK | \ 123 I2C_FUNC_SMBUS_BYTE | \ 124 I2C_FUNC_SMBUS_BYTE_DATA | \ 125 I2C_FUNC_SMBUS_WORD_DATA | \ 126 I2C_FUNC_SMBUS_PROC_CALL | \ 127 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \ 128 I2C_FUNC_SMBUS_I2C_BLOCK | \ 129 I2C_FUNC_SMBUS_PEC) 130 131/* 132 * Data for SMBus Messages 133 */ 134#define I2C_SMBUS_BLOCK_MAX 32 /* As specified in SMBus standard */ 135union i2c_smbus_data { 136 __u8 byte; 137 __u16 word; 138 __u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */ 139 /* and one more for user-space compatibility */ 140}; 141 142/* i2c_smbus_xfer read or write markers */ 143#define I2C_SMBUS_READ 1 144#define I2C_SMBUS_WRITE 0 145 146/* SMBus transaction types (size parameter in the above functions) 147 Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */ 148#define I2C_SMBUS_QUICK 0 149#define I2C_SMBUS_BYTE 1 150#define I2C_SMBUS_BYTE_DATA 2 151#define I2C_SMBUS_WORD_DATA 3 152#define I2C_SMBUS_PROC_CALL 4 153#define I2C_SMBUS_BLOCK_DATA 5 154#define I2C_SMBUS_I2C_BLOCK_BROKEN 6 155#define I2C_SMBUS_BLOCK_PROC_CALL 7 /* SMBus 2.0 */ 156#define I2C_SMBUS_I2C_BLOCK_DATA 8 157 158#endif /* _UAPI_LINUX_I2C_H */ 159