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1/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */2/*3 * i2c.h - definitions for the I2C bus interface4 *5 * Copyright (C) 1995-2000 Simon G. Vogl6 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and7 * Frodo Looijaard <frodol@dds.nl>8 */9 10#ifndef _UAPI_LINUX_I2C_H11#define _UAPI_LINUX_I2C_H12 13#include <linux/types.h>14 15/**16 * struct i2c_msg - an I2C transaction segment beginning with START17 *18 * @addr: Slave address, either 7 or 10 bits. When this is a 10 bit address,19 * %I2C_M_TEN must be set in @flags and the adapter must support20 * %I2C_FUNC_10BIT_ADDR.21 *22 * @flags:23 * Supported by all adapters:24 * %I2C_M_RD: read data (from slave to master). Guaranteed to be 0x0001!25 *26 * Optional:27 * %I2C_M_DMA_SAFE: the buffer of this message is DMA safe. Makes only sense28 * in kernelspace, because userspace buffers are copied anyway29 *30 * Only if I2C_FUNC_10BIT_ADDR is set:31 * %I2C_M_TEN: this is a 10 bit chip address32 *33 * Only if I2C_FUNC_SMBUS_READ_BLOCK_DATA is set:34 * %I2C_M_RECV_LEN: message length will be first received byte35 *36 * Only if I2C_FUNC_NOSTART is set:37 * %I2C_M_NOSTART: skip repeated start sequence38 39 * Only if I2C_FUNC_PROTOCOL_MANGLING is set:40 * %I2C_M_NO_RD_ACK: in a read message, master ACK/NACK bit is skipped41 * %I2C_M_IGNORE_NAK: treat NACK from client as ACK42 * %I2C_M_REV_DIR_ADDR: toggles the Rd/Wr bit43 * %I2C_M_STOP: force a STOP condition after the message44 *45 * @len: Number of data bytes in @buf being read from or written to the I2C46 * slave address. For read transactions where %I2C_M_RECV_LEN is set, the47 * caller guarantees that this buffer can hold up to %I2C_SMBUS_BLOCK_MAX48 * bytes in addition to the initial length byte sent by the slave (plus,49 * if used, the SMBus PEC); and this value will be incremented by the number50 * of block data bytes received.51 *52 * @buf: The buffer into which data is read, or from which it's written.53 *54 * An i2c_msg is the low level representation of one segment of an I2C55 * transaction. It is visible to drivers in the @i2c_transfer() procedure,56 * to userspace from i2c-dev, and to I2C adapter drivers through the57 * @i2c_adapter.@master_xfer() method.58 *59 * Except when I2C "protocol mangling" is used, all I2C adapters implement60 * the standard rules for I2C transactions. Each transaction begins with a61 * START. That is followed by the slave address, and a bit encoding read62 * versus write. Then follow all the data bytes, possibly including a byte63 * with SMBus PEC. The transfer terminates with a NAK, or when all those64 * bytes have been transferred and ACKed. If this is the last message in a65 * group, it is followed by a STOP. Otherwise it is followed by the next66 * @i2c_msg transaction segment, beginning with a (repeated) START.67 *68 * Alternatively, when the adapter supports %I2C_FUNC_PROTOCOL_MANGLING then69 * passing certain @flags may have changed those standard protocol behaviors.70 * Those flags are only for use with broken/nonconforming slaves, and with71 * adapters which are known to support the specific mangling options they need.72 */73struct i2c_msg {74 __u16 addr;75 __u16 flags;76#define I2C_M_RD 0x0001 /* guaranteed to be 0x0001! */77#define I2C_M_TEN 0x0010 /* use only if I2C_FUNC_10BIT_ADDR */78#define I2C_M_DMA_SAFE 0x0200 /* use only in kernel space */79#define I2C_M_RECV_LEN 0x0400 /* use only if I2C_FUNC_SMBUS_READ_BLOCK_DATA */80#define I2C_M_NO_RD_ACK 0x0800 /* use only if I2C_FUNC_PROTOCOL_MANGLING */81#define I2C_M_IGNORE_NAK 0x1000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */82#define I2C_M_REV_DIR_ADDR 0x2000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */83#define I2C_M_NOSTART 0x4000 /* use only if I2C_FUNC_NOSTART */84#define I2C_M_STOP 0x8000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */85 __u16 len;86 __u8 *buf;87};88 89/* To determine what functionality is present */90 91#define I2C_FUNC_I2C 0x0000000192#define I2C_FUNC_10BIT_ADDR 0x00000002 /* required for I2C_M_TEN */93#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* required for I2C_M_IGNORE_NAK etc. */94#define I2C_FUNC_SMBUS_PEC 0x0000000895#define I2C_FUNC_NOSTART 0x00000010 /* required for I2C_M_NOSTART */96#define I2C_FUNC_SLAVE 0x0000002097#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 or later */98#define I2C_FUNC_SMBUS_QUICK 0x0001000099#define I2C_FUNC_SMBUS_READ_BYTE 0x00020000100#define I2C_FUNC_SMBUS_WRITE_BYTE 0x00040000101#define I2C_FUNC_SMBUS_READ_BYTE_DATA 0x00080000102#define I2C_FUNC_SMBUS_WRITE_BYTE_DATA 0x00100000103#define I2C_FUNC_SMBUS_READ_WORD_DATA 0x00200000104#define I2C_FUNC_SMBUS_WRITE_WORD_DATA 0x00400000105#define I2C_FUNC_SMBUS_PROC_CALL 0x00800000106#define I2C_FUNC_SMBUS_READ_BLOCK_DATA 0x01000000 /* required for I2C_M_RECV_LEN */107#define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000108#define I2C_FUNC_SMBUS_READ_I2C_BLOCK 0x04000000 /* I2C-like block xfer */109#define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK 0x08000000 /* w/ 1-byte reg. addr. */110#define I2C_FUNC_SMBUS_HOST_NOTIFY 0x10000000 /* SMBus 2.0 or later */111 112#define I2C_FUNC_SMBUS_BYTE (I2C_FUNC_SMBUS_READ_BYTE | \113 I2C_FUNC_SMBUS_WRITE_BYTE)114#define I2C_FUNC_SMBUS_BYTE_DATA (I2C_FUNC_SMBUS_READ_BYTE_DATA | \115 I2C_FUNC_SMBUS_WRITE_BYTE_DATA)116#define I2C_FUNC_SMBUS_WORD_DATA (I2C_FUNC_SMBUS_READ_WORD_DATA | \117 I2C_FUNC_SMBUS_WRITE_WORD_DATA)118#define I2C_FUNC_SMBUS_BLOCK_DATA (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \119 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)120#define I2C_FUNC_SMBUS_I2C_BLOCK (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \121 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)122 123#define I2C_FUNC_SMBUS_EMUL (I2C_FUNC_SMBUS_QUICK | \124 I2C_FUNC_SMBUS_BYTE | \125 I2C_FUNC_SMBUS_BYTE_DATA | \126 I2C_FUNC_SMBUS_WORD_DATA | \127 I2C_FUNC_SMBUS_PROC_CALL | \128 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \129 I2C_FUNC_SMBUS_I2C_BLOCK | \130 I2C_FUNC_SMBUS_PEC)131 132/* if I2C_M_RECV_LEN is also supported */133#define I2C_FUNC_SMBUS_EMUL_ALL (I2C_FUNC_SMBUS_EMUL | \134 I2C_FUNC_SMBUS_READ_BLOCK_DATA | \135 I2C_FUNC_SMBUS_BLOCK_PROC_CALL)136 137/*138 * Data for SMBus Messages139 */140#define I2C_SMBUS_BLOCK_MAX 32 /* As specified in SMBus standard */141union i2c_smbus_data {142 __u8 byte;143 __u16 word;144 __u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */145 /* and one more for user-space compatibility */146};147 148/* i2c_smbus_xfer read or write markers */149#define I2C_SMBUS_READ 1150#define I2C_SMBUS_WRITE 0151 152/* SMBus transaction types (size parameter in the above functions)153 Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */154#define I2C_SMBUS_QUICK 0155#define I2C_SMBUS_BYTE 1156#define I2C_SMBUS_BYTE_DATA 2157#define I2C_SMBUS_WORD_DATA 3158#define I2C_SMBUS_PROC_CALL 4159#define I2C_SMBUS_BLOCK_DATA 5160#define I2C_SMBUS_I2C_BLOCK_BROKEN 6161#define I2C_SMBUS_BLOCK_PROC_CALL 7 /* SMBus 2.0 */162#define I2C_SMBUS_I2C_BLOCK_DATA 8163 164#endif /* _UAPI_LINUX_I2C_H */165