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001: /* ------------------------------------------------------------------------- */
002: /*                                                                           */
003: /* i2c.h - definitions for the i2c-bus interface                             */
004: /*                                                                           */
005: /* ------------------------------------------------------------------------- */
006: /*   Copyright (C) 1995-2000 Simon G. Vogl
007: 
008:     This program is free software; you can redistribute it and/or modify
009:     it under the terms of the GNU General Public License as published by
010:     the Free Software Foundation; either version 2 of the License, or
011:     (at your option) any later version.
012: 
013:     This program is distributed in the hope that it will be useful,
014:     but WITHOUT ANY WARRANTY; without even the implied warranty of
015:     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
016:     GNU General Public License for more details.
017: 
018:     You should have received a copy of the GNU General Public License
019:     along with this program; if not, write to the Free Software
020:     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                */
021: /* ------------------------------------------------------------------------- */
022: 
023: /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
024:    Frodo Looijaard <frodol@dds.nl> */
025: 
026: #ifndef _LINUX_I2C_H
027: #define _LINUX_I2C_H
028: 
029: #include <linux/types.h>
030: 
031: /**
032:  * struct i2c_msg - an I2C transaction segment beginning with START
033:  * @addr: Slave address, either seven or ten bits.  When this is a ten
034:  *      bit address, I2C_M_TEN must be set in @flags and the adapter
035:  *      must support I2C_FUNC_10BIT_ADDR.
036:  * @flags: I2C_M_RD is handled by all adapters.  No other flags may be
037:  *      provided unless the adapter exported the relevant I2C_FUNC_*
038:  *      flags through i2c_check_functionality().
039:  * @len: Number of data bytes in @buf being read from or written to the
040:  *      I2C slave address.  For read transactions where I2C_M_RECV_LEN
041:  *      is set, the caller guarantees that this buffer can hold up to
042:  *      32 bytes in addition to the initial length byte sent by the
043:  *      slave (plus, if used, the SMBus PEC); and this value will be
044:  *      incremented by the number of block data bytes received.
045:  * @buf: The buffer into which data is read, or from which it's written.
046:  *
047:  * An i2c_msg is the low level representation of one segment of an I2C
048:  * transaction.  It is visible to drivers in the @i2c_transfer() procedure,
049:  * to userspace from i2c-dev, and to I2C adapter drivers through the
050:  * @i2c_adapter.@master_xfer() method.
051:  *
052:  * Except when I2C "protocol mangling" is used, all I2C adapters implement
053:  * the standard rules for I2C transactions.  Each transaction begins with a
054:  * START.  That is followed by the slave address, and a bit encoding read
055:  * versus write.  Then follow all the data bytes, possibly including a byte
056:  * with SMBus PEC.  The transfer terminates with a NAK, or when all those
057:  * bytes have been transferred and ACKed.  If this is the last message in a
058:  * group, it is followed by a STOP.  Otherwise it is followed by the next
059:  * @i2c_msg transaction segment, beginning with a (repeated) START.
060:  *
061:  * Alternatively, when the adapter supports I2C_FUNC_PROTOCOL_MANGLING then
062:  * passing certain @flags may have changed those standard protocol behaviors.
063:  * Those flags are only for use with broken/nonconforming slaves, and with
064:  * adapters which are known to support the specific mangling options they
065:  * need (one or more of IGNORE_NAK, NO_RD_ACK, NOSTART, and REV_DIR_ADDR).
066:  */
067: struct i2c_msg {
068:         __u16 addr;     /* slave address                        */
069:         __u16 flags;
070: #define I2C_M_TEN               0x0010  /* this is a ten bit chip address */
071: #define I2C_M_RD                0x0001  /* read data, from slave to master */
072: #define I2C_M_NOSTART           0x4000  /* if I2C_FUNC_PROTOCOL_MANGLING */
073: #define I2C_M_REV_DIR_ADDR      0x2000  /* if I2C_FUNC_PROTOCOL_MANGLING */
074: #define I2C_M_IGNORE_NAK        0x1000  /* if I2C_FUNC_PROTOCOL_MANGLING */
075: #define I2C_M_NO_RD_ACK         0x0800  /* if I2C_FUNC_PROTOCOL_MANGLING */
076: #define I2C_M_RECV_LEN          0x0400  /* length will be first received byte */
077:         __u16 len;              /* msg length                           */
078:         __u8 *buf;              /* pointer to msg data                  */
079: };
080: 
081: /* To determine what functionality is present */
082: 
083: #define I2C_FUNC_I2C                    0x00000001
084: #define I2C_FUNC_10BIT_ADDR             0x00000002
085: #define I2C_FUNC_PROTOCOL_MANGLING      0x00000004 /* I2C_M_NOSTART etc. */
086: #define I2C_FUNC_SMBUS_PEC              0x00000008
087: #define I2C_FUNC_SMBUS_BLOCK_PROC_CALL  0x00008000 /* SMBus 2.0 */
088: #define I2C_FUNC_SMBUS_QUICK            0x00010000
089: #define I2C_FUNC_SMBUS_READ_BYTE        0x00020000
090: #define I2C_FUNC_SMBUS_WRITE_BYTE       0x00040000
091: #define I2C_FUNC_SMBUS_READ_BYTE_DATA   0x00080000
092: #define I2C_FUNC_SMBUS_WRITE_BYTE_DATA  0x00100000
093: #define I2C_FUNC_SMBUS_READ_WORD_DATA   0x00200000
094: #define I2C_FUNC_SMBUS_WRITE_WORD_DATA  0x00400000
095: #define I2C_FUNC_SMBUS_PROC_CALL        0x00800000
096: #define I2C_FUNC_SMBUS_READ_BLOCK_DATA  0x01000000
097: #define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000
098: #define I2C_FUNC_SMBUS_READ_I2C_BLOCK   0x04000000 /* I2C-like block xfer  */
099: #define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK  0x08000000 /* w/ 1-byte reg. addr. */
100: 
101: #define I2C_FUNC_SMBUS_BYTE             (I2C_FUNC_SMBUS_READ_BYTE | \
102:                                          I2C_FUNC_SMBUS_WRITE_BYTE)
103: #define I2C_FUNC_SMBUS_BYTE_DATA        (I2C_FUNC_SMBUS_READ_BYTE_DATA | \
104:                                          I2C_FUNC_SMBUS_WRITE_BYTE_DATA)
105: #define I2C_FUNC_SMBUS_WORD_DATA        (I2C_FUNC_SMBUS_READ_WORD_DATA | \
106:                                          I2C_FUNC_SMBUS_WRITE_WORD_DATA)
107: #define I2C_FUNC_SMBUS_BLOCK_DATA       (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \
108:                                          I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)
109: #define I2C_FUNC_SMBUS_I2C_BLOCK        (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \
110:                                          I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)
111: 
112: #define I2C_FUNC_SMBUS_EMUL             (I2C_FUNC_SMBUS_QUICK | \
113:                                          I2C_FUNC_SMBUS_BYTE | \
114:                                          I2C_FUNC_SMBUS_BYTE_DATA | \
115:                                          I2C_FUNC_SMBUS_WORD_DATA | \
116:                                          I2C_FUNC_SMBUS_PROC_CALL | \
117:                                          I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \
118:                                          I2C_FUNC_SMBUS_I2C_BLOCK | \
119:                                          I2C_FUNC_SMBUS_PEC)
120: 
121: /*
122:  * Data for SMBus Messages
123:  */
124: #define I2C_SMBUS_BLOCK_MAX     32      /* As specified in SMBus standard */
125: union i2c_smbus_data {
126:         __u8 byte;
127:         __u16 word;
128:         __u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
129:                                /* and one more for user-space compatibility */
130: };
131: 
132: /* i2c_smbus_xfer read or write markers */
133: #define I2C_SMBUS_READ  1
134: #define I2C_SMBUS_WRITE 0
135: 
136: /* SMBus transaction types (size parameter in the above functions)
137:    Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
138: #define I2C_SMBUS_QUICK             0
139: #define I2C_SMBUS_BYTE              1
140: #define I2C_SMBUS_BYTE_DATA         2
141: #define I2C_SMBUS_WORD_DATA         3
142: #define I2C_SMBUS_PROC_CALL         4
143: #define I2C_SMBUS_BLOCK_DATA        5
144: #define I2C_SMBUS_I2C_BLOCK_BROKEN  6
145: #define I2C_SMBUS_BLOCK_PROC_CALL   7           /* SMBus 2.0 */
146: #define I2C_SMBUS_I2C_BLOCK_DATA    8
147: 
148: #endif /* _LINUX_I2C_H */
149: 

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