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Diffstat (limited to 'include/uapi/linux/i2c.h')
| -rw-r--r-- | include/uapi/linux/i2c.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h new file mode 100644 index 000000000..0e949cbfd --- /dev/null +++ b/include/uapi/linux/i2c.h @@ -0,0 +1,151 @@ +/* ------------------------------------------------------------------------- */ +/* */ +/* i2c.h - definitions for the i2c-bus interface */ +/* */ +/* ------------------------------------------------------------------------- */ +/* Copyright (C) 1995-2000 Simon G. Vogl + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + MA 02110-1301 USA. */ +/* ------------------------------------------------------------------------- */ + +/* 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 seven or ten bits. When this is a ten + * bit address, I2C_M_TEN must be set in @flags and the adapter + * must support I2C_FUNC_10BIT_ADDR. + * @flags: I2C_M_RD is handled by all adapters. No other flags may be + * provided unless the adapter exported the relevant I2C_FUNC_* + * flags through i2c_check_functionality(). + * @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 + * 32 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 (one or more of IGNORE_NAK, NO_RD_ACK, NOSTART, and REV_DIR_ADDR). + */ +struct i2c_msg { + __u16 addr; /* slave address */ + __u16 flags; +#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */ +#define I2C_M_RD 0x0001 /* read data, from slave to master */ +#define I2C_M_STOP 0x8000 /* if I2C_FUNC_PROTOCOL_MANGLING */ +#define I2C_M_NOSTART 0x4000 /* if I2C_FUNC_NOSTART */ +#define I2C_M_REV_DIR_ADDR 0x2000 /* if I2C_FUNC_PROTOCOL_MANGLING */ +#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */ +#define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */ +#define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */ + __u16 len; /* msg length */ + __u8 *buf; /* pointer to msg data */ +}; + +/* To determine what functionality is present */ + +#define I2C_FUNC_I2C 0x00000001 +#define I2C_FUNC_10BIT_ADDR 0x00000002 +#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* I2C_M_IGNORE_NAK etc. */ +#define I2C_FUNC_SMBUS_PEC 0x00000008 +#define I2C_FUNC_NOSTART 0x00000010 /* I2C_M_NOSTART */ +#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 */ +#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 +#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_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) + +/* + * 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 */ |