/* 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 <kmalkki@cc.hut.fi> and * Frodo Looijaard <frodol@dds.nl> */ #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 */