| /* ------------------------------------------------------------------------- */ |
| /* */ |
| /* 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| /* ------------------------------------------------------------------------- */ |
| |
| /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and |
| Frodo Looijaard <frodol@dds.nl> */ |
| |
| #ifndef _LINUX_I2C_H |
| #define _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_NOSTART 0x4000 /* if I2C_FUNC_PROTOCOL_MANGLING */ |
| #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_NOSTART etc. */ |
| #define I2C_FUNC_SMBUS_PEC 0x00000008 |
| #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 /* _LINUX_I2C_H */ |
