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Diffstat (limited to 'include/uapi/linux/i2c.h')
| -rw-r--r-- | include/uapi/linux/i2c.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h new file mode 100644 index 000000000..92326ebde --- /dev/null +++ b/include/uapi/linux/i2c.h @@ -0,0 +1,164 @@ +/* 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 */ |