summaryrefslogtreecommitdiffstats
path: root/include/uapi/linux/i2c.h
blob: f71a1751cacf40e21ae399cd55f5790b5e312147 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
/* 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

    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_RD		0x0001	/* read data, from slave to master */
					/* I2C_M_RD is guaranteed to be 0x0001! */
#define I2C_M_TEN		0x0010	/* this is a ten bit chip address */
#define I2C_M_DMA_SAFE		0x0200	/* the buffer of this message is DMA safe */
					/* makes only sense in kernelspace */
					/* userspace buffers are copied anyway */
#define I2C_M_RECV_LEN		0x0400	/* length will be first received byte */
#define I2C_M_NO_RD_ACK		0x0800	/* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_IGNORE_NAK	0x1000	/* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_REV_DIR_ADDR	0x2000	/* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_NOSTART		0x4000	/* if I2C_FUNC_NOSTART */
#define I2C_M_STOP		0x8000	/* if I2C_FUNC_PROTOCOL_MANGLING */
	__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_SLAVE			0x00000020
#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_HOST_NOTIFY	0x10000000

#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 */
OpenPOWER on IntegriCloud