1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ 2 /* ------------------------------------------------------------------------- */ 3 /* */ 4 /* i2c.h - definitions for the i2c-bus interface */ 5 /* */ 6 /* ------------------------------------------------------------------------- */ 7 /* Copyright (C) 1995-2000 Simon G. Vogl 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 2 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 22 MA 02110-1301 USA. */ 23 /* ------------------------------------------------------------------------- */ 24 25 /* With some changes from Kyösti Mälkki <[email protected]> and 26 Frodo Looijaard <[email protected]> */ 27 28 #ifndef _UAPI_LINUX_I2C_H 29 #define _UAPI_LINUX_I2C_H 30 31 #include <linux/types.h> 32 33 /** 34 * struct i2c_msg - an I2C transaction segment beginning with START 35 * 36 * @addr: Slave address, either 7 or 10 bits. When this is a 10 bit address, 37 * %I2C_M_TEN must be set in @flags and the adapter must support 38 * %I2C_FUNC_10BIT_ADDR. 39 * 40 * @flags: 41 * Supported by all adapters: 42 * %I2C_M_RD: read data (from slave to master). Guaranteed to be 0x0001! 43 * 44 * Optional: 45 * %I2C_M_DMA_SAFE: the buffer of this message is DMA safe. Makes only sense 46 * in kernelspace, because userspace buffers are copied anyway 47 * 48 * Only if I2C_FUNC_10BIT_ADDR is set: 49 * %I2C_M_TEN: this is a 10 bit chip address 50 * 51 * Only if I2C_FUNC_SMBUS_READ_BLOCK_DATA is set: 52 * %I2C_M_RECV_LEN: message length will be first received byte 53 * 54 * Only if I2C_FUNC_NOSTART is set: 55 * %I2C_M_NOSTART: skip repeated start sequence 56 57 * Only if I2C_FUNC_PROTOCOL_MANGLING is set: 58 * %I2C_M_NO_RD_ACK: in a read message, master ACK/NACK bit is skipped 59 * %I2C_M_IGNORE_NAK: treat NACK from client as ACK 60 * %I2C_M_REV_DIR_ADDR: toggles the Rd/Wr bit 61 * %I2C_M_STOP: force a STOP condition after the message 62 * 63 * @len: Number of data bytes in @buf being read from or written to the I2C 64 * slave address. For read transactions where %I2C_M_RECV_LEN is set, the 65 * caller guarantees that this buffer can hold up to %I2C_SMBUS_BLOCK_MAX 66 * bytes in addition to the initial length byte sent by the slave (plus, 67 * if used, the SMBus PEC); and this value will be incremented by the number 68 * of block data bytes received. 69 * 70 * @buf: The buffer into which data is read, or from which it's written. 71 * 72 * An i2c_msg is the low level representation of one segment of an I2C 73 * transaction. It is visible to drivers in the @i2c_transfer() procedure, 74 * to userspace from i2c-dev, and to I2C adapter drivers through the 75 * @i2c_adapter.@master_xfer() method. 76 * 77 * Except when I2C "protocol mangling" is used, all I2C adapters implement 78 * the standard rules for I2C transactions. Each transaction begins with a 79 * START. That is followed by the slave address, and a bit encoding read 80 * versus write. Then follow all the data bytes, possibly including a byte 81 * with SMBus PEC. The transfer terminates with a NAK, or when all those 82 * bytes have been transferred and ACKed. If this is the last message in a 83 * group, it is followed by a STOP. Otherwise it is followed by the next 84 * @i2c_msg transaction segment, beginning with a (repeated) START. 85 * 86 * Alternatively, when the adapter supports %I2C_FUNC_PROTOCOL_MANGLING then 87 * passing certain @flags may have changed those standard protocol behaviors. 88 * Those flags are only for use with broken/nonconforming slaves, and with 89 * adapters which are known to support the specific mangling options they need. 90 */ 91 struct i2c_msg { 92 __u16 addr; 93 __u16 flags; 94 #define I2C_M_RD 0x0001 /* guaranteed to be 0x0001! */ 95 #define I2C_M_TEN 0x0010 /* use only if I2C_FUNC_10BIT_ADDR */ 96 #define I2C_M_DMA_SAFE 0x0200 /* use only in kernel space */ 97 #define I2C_M_RECV_LEN 0x0400 /* use only if I2C_FUNC_SMBUS_READ_BLOCK_DATA */ 98 #define I2C_M_NO_RD_ACK 0x0800 /* use only if I2C_FUNC_PROTOCOL_MANGLING */ 99 #define I2C_M_IGNORE_NAK 0x1000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */ 100 #define I2C_M_REV_DIR_ADDR 0x2000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */ 101 #define I2C_M_NOSTART 0x4000 /* use only if I2C_FUNC_NOSTART */ 102 #define I2C_M_STOP 0x8000 /* use only if I2C_FUNC_PROTOCOL_MANGLING */ 103 __u16 len; 104 __u8 *buf; 105 }; 106 107 /* To determine what functionality is present */ 108 109 #define I2C_FUNC_I2C 0x00000001 110 #define I2C_FUNC_10BIT_ADDR 0x00000002 /* required for I2C_M_TEN */ 111 #define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* required for I2C_M_IGNORE_NAK etc. */ 112 #define I2C_FUNC_SMBUS_PEC 0x00000008 113 #define I2C_FUNC_NOSTART 0x00000010 /* required for I2C_M_NOSTART */ 114 #define I2C_FUNC_SLAVE 0x00000020 115 #define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 or later */ 116 #define I2C_FUNC_SMBUS_QUICK 0x00010000 117 #define I2C_FUNC_SMBUS_READ_BYTE 0x00020000 118 #define I2C_FUNC_SMBUS_WRITE_BYTE 0x00040000 119 #define I2C_FUNC_SMBUS_READ_BYTE_DATA 0x00080000 120 #define I2C_FUNC_SMBUS_WRITE_BYTE_DATA 0x00100000 121 #define I2C_FUNC_SMBUS_READ_WORD_DATA 0x00200000 122 #define I2C_FUNC_SMBUS_WRITE_WORD_DATA 0x00400000 123 #define I2C_FUNC_SMBUS_PROC_CALL 0x00800000 124 #define I2C_FUNC_SMBUS_READ_BLOCK_DATA 0x01000000 /* required for I2C_M_RECV_LEN */ 125 #define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000 126 #define I2C_FUNC_SMBUS_READ_I2C_BLOCK 0x04000000 /* I2C-like block xfer */ 127 #define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK 0x08000000 /* w/ 1-byte reg. addr. */ 128 #define I2C_FUNC_SMBUS_HOST_NOTIFY 0x10000000 /* SMBus 2.0 or later */ 129 130 #define I2C_FUNC_SMBUS_BYTE (I2C_FUNC_SMBUS_READ_BYTE | \ 131 I2C_FUNC_SMBUS_WRITE_BYTE) 132 #define I2C_FUNC_SMBUS_BYTE_DATA (I2C_FUNC_SMBUS_READ_BYTE_DATA | \ 133 I2C_FUNC_SMBUS_WRITE_BYTE_DATA) 134 #define I2C_FUNC_SMBUS_WORD_DATA (I2C_FUNC_SMBUS_READ_WORD_DATA | \ 135 I2C_FUNC_SMBUS_WRITE_WORD_DATA) 136 #define I2C_FUNC_SMBUS_BLOCK_DATA (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \ 137 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) 138 #define I2C_FUNC_SMBUS_I2C_BLOCK (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \ 139 I2C_FUNC_SMBUS_WRITE_I2C_BLOCK) 140 141 #define I2C_FUNC_SMBUS_EMUL (I2C_FUNC_SMBUS_QUICK | \ 142 I2C_FUNC_SMBUS_BYTE | \ 143 I2C_FUNC_SMBUS_BYTE_DATA | \ 144 I2C_FUNC_SMBUS_WORD_DATA | \ 145 I2C_FUNC_SMBUS_PROC_CALL | \ 146 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \ 147 I2C_FUNC_SMBUS_I2C_BLOCK | \ 148 I2C_FUNC_SMBUS_PEC) 149 150 /* 151 * Data for SMBus Messages 152 */ 153 #define I2C_SMBUS_BLOCK_MAX 32 /* As specified in SMBus standard */ 154 union i2c_smbus_data { 155 __u8 byte; 156 __u16 word; 157 __u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */ 158 /* and one more for user-space compatibility */ 159 }; 160 161 /* i2c_smbus_xfer read or write markers */ 162 #define I2C_SMBUS_READ 1 163 #define I2C_SMBUS_WRITE 0 164 165 /* SMBus transaction types (size parameter in the above functions) 166 Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */ 167 #define I2C_SMBUS_QUICK 0 168 #define I2C_SMBUS_BYTE 1 169 #define I2C_SMBUS_BYTE_DATA 2 170 #define I2C_SMBUS_WORD_DATA 3 171 #define I2C_SMBUS_PROC_CALL 4 172 #define I2C_SMBUS_BLOCK_DATA 5 173 #define I2C_SMBUS_I2C_BLOCK_BROKEN 6 174 #define I2C_SMBUS_BLOCK_PROC_CALL 7 /* SMBus 2.0 */ 175 #define I2C_SMBUS_I2C_BLOCK_DATA 8 176 177 #endif /* _UAPI_LINUX_I2C_H */ 178