1 /* ------------------------------------------------------------------------- */ 2 /* */ 3 /* i2c.h - definitions for the i2c-bus interface */ 4 /* */ 5 /* ------------------------------------------------------------------------- */ 6 /* Copyright (C) 1995-2000 Simon G. Vogl 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 2 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program; if not, write to the Free Software 20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ 21 /* ------------------------------------------------------------------------- */ 22 23 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and 24 Frodo Looijaard <frodol@dds.nl> */ 25 26 #ifndef _LINUX_I2C_H 27 #define _LINUX_I2C_H 28 29 #include <linux/types.h> 30 31 /** 32 * struct i2c_msg - an I2C transaction segment beginning with START 33 * @addr: Slave address, either seven or ten bits. When this is a ten 34 * bit address, I2C_M_TEN must be set in @flags and the adapter 35 * must support I2C_FUNC_10BIT_ADDR. 36 * @flags: I2C_M_RD is handled by all adapters. No other flags may be 37 * provided unless the adapter exported the relevant I2C_FUNC_* 38 * flags through i2c_check_functionality(). 39 * @len: Number of data bytes in @buf being read from or written to the 40 * I2C slave address. For read transactions where I2C_M_RECV_LEN 41 * is set, the caller guarantees that this buffer can hold up to 42 * 32 bytes in addition to the initial length byte sent by the 43 * slave (plus, if used, the SMBus PEC); and this value will be 44 * incremented by the number of block data bytes received. 45 * @buf: The buffer into which data is read, or from which it's written. 46 * 47 * An i2c_msg is the low level representation of one segment of an I2C 48 * transaction. It is visible to drivers in the @i2c_transfer() procedure, 49 * to userspace from i2c-dev, and to I2C adapter drivers through the 50 * @i2c_adapter.@master_xfer() method. 51 * 52 * Except when I2C "protocol mangling" is used, all I2C adapters implement 53 * the standard rules for I2C transactions. Each transaction begins with a 54 * START. That is followed by the slave address, and a bit encoding read 55 * versus write. Then follow all the data bytes, possibly including a byte 56 * with SMBus PEC. The transfer terminates with a NAK, or when all those 57 * bytes have been transferred and ACKed. If this is the last message in a 58 * group, it is followed by a STOP. Otherwise it is followed by the next 59 * @i2c_msg transaction segment, beginning with a (repeated) START. 60 * 61 * Alternatively, when the adapter supports I2C_FUNC_PROTOCOL_MANGLING then 62 * passing certain @flags may have changed those standard protocol behaviors. 63 * Those flags are only for use with broken/nonconforming slaves, and with 64 * adapters which are known to support the specific mangling options they 65 * need (one or more of IGNORE_NAK, NO_RD_ACK, NOSTART, and REV_DIR_ADDR). 66 */ 67 struct i2c_msg { 68 __u16 addr; /* slave address */ 69 __u16 flags; 70 #define I2C_M_TEN 0x0010 /* this is a ten bit chip address */ 71 #define I2C_M_RD 0x0001 /* read data, from slave to master */ 72 #define I2C_M_NOSTART 0x4000 /* if I2C_FUNC_PROTOCOL_MANGLING */ 73 #define I2C_M_REV_DIR_ADDR 0x2000 /* if I2C_FUNC_PROTOCOL_MANGLING */ 74 #define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */ 75 #define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */ 76 #define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */ 77 __u16 len; /* msg length */ 78 __u8 *buf; /* pointer to msg data */ 79 }; 80 81 /* To determine what functionality is present */ 82 83 #define I2C_FUNC_I2C 0x00000001 84 #define I2C_FUNC_10BIT_ADDR 0x00000002 85 #define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* I2C_M_{REV_DIR_ADDR,NOSTART,..} */ 86 #define I2C_FUNC_SMBUS_PEC 0x00000008 87 #define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 */ 88 #define I2C_FUNC_SMBUS_QUICK 0x00010000 89 #define I2C_FUNC_SMBUS_READ_BYTE 0x00020000 90 #define I2C_FUNC_SMBUS_WRITE_BYTE 0x00040000 91 #define I2C_FUNC_SMBUS_READ_BYTE_DATA 0x00080000 92 #define I2C_FUNC_SMBUS_WRITE_BYTE_DATA 0x00100000 93 #define I2C_FUNC_SMBUS_READ_WORD_DATA 0x00200000 94 #define I2C_FUNC_SMBUS_WRITE_WORD_DATA 0x00400000 95 #define I2C_FUNC_SMBUS_PROC_CALL 0x00800000 96 #define I2C_FUNC_SMBUS_READ_BLOCK_DATA 0x01000000 97 #define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000 98 #define I2C_FUNC_SMBUS_READ_I2C_BLOCK 0x04000000 /* I2C-like block xfer */ 99 #define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK 0x08000000 /* w/ 1-byte reg. addr. */ 100 #define I2C_FUNC_SMBUS_READ_I2C_BLOCK_2 0x10000000 /* I2C-like block xfer */ 101 #define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK_2 0x20000000 /* w/ 2-byte reg. addr. */ 102 103 #define I2C_FUNC_SMBUS_BYTE (I2C_FUNC_SMBUS_READ_BYTE | \ 104 I2C_FUNC_SMBUS_WRITE_BYTE) 105 #define I2C_FUNC_SMBUS_BYTE_DATA (I2C_FUNC_SMBUS_READ_BYTE_DATA | \ 106 I2C_FUNC_SMBUS_WRITE_BYTE_DATA) 107 #define I2C_FUNC_SMBUS_WORD_DATA (I2C_FUNC_SMBUS_READ_WORD_DATA | \ 108 I2C_FUNC_SMBUS_WRITE_WORD_DATA) 109 #define I2C_FUNC_SMBUS_BLOCK_DATA (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \ 110 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) 111 #define I2C_FUNC_SMBUS_I2C_BLOCK (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \ 112 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK) 113 #define I2C_FUNC_SMBUS_I2C_BLOCK_2 (I2C_FUNC_SMBUS_READ_I2C_BLOCK_2 | \ 114 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK_2) 115 116 #define I2C_FUNC_SMBUS_EMUL (I2C_FUNC_SMBUS_QUICK | \ 117 I2C_FUNC_SMBUS_BYTE | \ 118 I2C_FUNC_SMBUS_BYTE_DATA | \ 119 I2C_FUNC_SMBUS_WORD_DATA | \ 120 I2C_FUNC_SMBUS_PROC_CALL | \ 121 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \ 122 I2C_FUNC_SMBUS_I2C_BLOCK | \ 123 I2C_FUNC_SMBUS_PEC) 124 125 /* 126 * Data for SMBus Messages 127 */ 128 #define I2C_SMBUS_BLOCK_MAX 32 /* As specified in SMBus standard */ 129 union i2c_smbus_data { 130 __u8 byte; 131 __u16 word; 132 __u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */ 133 /* and one more for user-space compatibility */ 134 }; 135 136 /* smbus_access read or write markers */ 137 #define I2C_SMBUS_READ 1 138 #define I2C_SMBUS_WRITE 0 139 140 /* SMBus transaction types (size parameter in the above functions) 141 Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */ 142 #define I2C_SMBUS_QUICK 0 143 #define I2C_SMBUS_BYTE 1 144 #define I2C_SMBUS_BYTE_DATA 2 145 #define I2C_SMBUS_WORD_DATA 3 146 #define I2C_SMBUS_PROC_CALL 4 147 #define I2C_SMBUS_BLOCK_DATA 5 148 #define I2C_SMBUS_I2C_BLOCK_BROKEN 6 149 #define I2C_SMBUS_BLOCK_PROC_CALL 7 /* SMBus 2.0 */ 150 #define I2C_SMBUS_I2C_BLOCK_DATA 8 151 152 153 #endif /* _LINUX_I2C_H */ 154