/* smbus.c - SMBus level access helper functions Copyright (C) 1995-1997 Simon G. Vogl Copyright (C) 1998-1999 Frodo Looijaard Copyright (C) 2012-2013 Jean Delvare 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. */ #include #include #include "smbus.h" #include #include #include #include /* Compatibility defines */ #ifndef I2C_SMBUS_I2C_BLOCK_BROKEN #define I2C_SMBUS_I2C_BLOCK_BROKEN I2C_SMBUS_I2C_BLOCK_DATA #endif #ifndef I2C_FUNC_SMBUS_PEC #define I2C_FUNC_SMBUS_PEC I2C_FUNC_SMBUS_HWPEC_CALC #endif __s32 i2c_smbus_access(int file, char read_write, __u8 command, int size, union i2c_smbus_data *data) { struct i2c_smbus_ioctl_data args; __s32 err; args.read_write = read_write; args.command = command; args.size = size; args.data = data; err = ioctl(file, I2C_SMBUS, &args); if (err == -1) err = -errno; return err; } __s32 i2c_smbus_write_quick(int file, __u8 value) { return i2c_smbus_access(file, value, 0, I2C_SMBUS_QUICK, NULL); } __s32 i2c_smbus_read_byte(int file) { union i2c_smbus_data data; int err; err = i2c_smbus_access(file, I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data); if (err < 0) return err; return 0x0FF & data.byte; } __s32 i2c_smbus_write_byte(int file, __u8 value) { return i2c_smbus_access(file, I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL); } __s32 i2c_smbus_read_byte_data(int file, __u8 command) { union i2c_smbus_data data; int err; err = i2c_smbus_access(file, I2C_SMBUS_READ, command, I2C_SMBUS_BYTE_DATA, &data); if (err < 0) return err; return 0x0FF & data.byte; } __s32 i2c_smbus_write_byte_data(int file, __u8 command, __u8 value) { union i2c_smbus_data data; data.byte = value; return i2c_smbus_access(file, I2C_SMBUS_WRITE, command, I2C_SMBUS_BYTE_DATA, &data); } __s32 i2c_smbus_read_word_data(int file, __u8 command) { union i2c_smbus_data data; int err; err = i2c_smbus_access(file, I2C_SMBUS_READ, command, I2C_SMBUS_WORD_DATA, &data); if (err < 0) return err; return 0x0FFFF & data.word; } __s32 i2c_smbus_write_word_data(int file, __u8 command, __u16 value) { union i2c_smbus_data data; data.word = value; return i2c_smbus_access(file, I2C_SMBUS_WRITE, command, I2C_SMBUS_WORD_DATA, &data); } __s32 i2c_smbus_process_call(int file, __u8 command, __u16 value) { union i2c_smbus_data data; data.word = value; if (i2c_smbus_access(file, I2C_SMBUS_WRITE, command, I2C_SMBUS_PROC_CALL, &data)) return -1; else return 0x0FFFF & data.word; } /* Returns the number of read bytes */ __s32 i2c_smbus_read_block_data(int file, __u8 command, __u8 *values) { union i2c_smbus_data data; int i, err; err = i2c_smbus_access(file, I2C_SMBUS_READ, command, I2C_SMBUS_BLOCK_DATA, &data); if (err < 0) return err; for (i = 1; i <= data.block[0]; i++) values[i-1] = data.block[i]; return data.block[0]; } __s32 i2c_smbus_write_block_data(int file, __u8 command, __u8 length, const __u8 *values) { union i2c_smbus_data data; int i; if (length > I2C_SMBUS_BLOCK_MAX) length = I2C_SMBUS_BLOCK_MAX; for (i = 1; i <= length; i++) data.block[i] = values[i-1]; data.block[0] = length; return i2c_smbus_access(file, I2C_SMBUS_WRITE, command, I2C_SMBUS_BLOCK_DATA, &data); } /* Returns the number of read bytes */ /* Until kernel 2.6.22, the length is hardcoded to 32 bytes. If you ask for less than 32 bytes, your code will only work with kernels 2.6.23 and later. */ __s32 i2c_smbus_read_i2c_block_data(int file, __u8 command, __u8 length, __u8 *values) { union i2c_smbus_data data; int i, err; if (length > I2C_SMBUS_BLOCK_MAX) length = I2C_SMBUS_BLOCK_MAX; data.block[0] = length; err = i2c_smbus_access(file, I2C_SMBUS_READ, command, length == 32 ? I2C_SMBUS_I2C_BLOCK_BROKEN : I2C_SMBUS_I2C_BLOCK_DATA, &data); if (err < 0) return err; for (i = 1; i <= data.block[0]; i++) values[i-1] = data.block[i]; return data.block[0]; } __s32 i2c_smbus_write_i2c_block_data(int file, __u8 command, __u8 length, const __u8 *values) { union i2c_smbus_data data; int i; if (length > I2C_SMBUS_BLOCK_MAX) length = I2C_SMBUS_BLOCK_MAX; for (i = 1; i <= length; i++) data.block[i] = values[i-1]; data.block[0] = length; return i2c_smbus_access(file, I2C_SMBUS_WRITE, command, I2C_SMBUS_I2C_BLOCK_BROKEN, &data); } /* Returns the number of read bytes */ __s32 i2c_smbus_block_process_call(int file, __u8 command, __u8 length, __u8 *values) { union i2c_smbus_data data; int i, err; if (length > I2C_SMBUS_BLOCK_MAX) length = I2C_SMBUS_BLOCK_MAX; for (i = 1; i <= length; i++) data.block[i] = values[i-1]; data.block[0] = length; err = i2c_smbus_access(file, I2C_SMBUS_WRITE, command, I2C_SMBUS_BLOCK_PROC_CALL, &data); if (err < 0) return err; for (i = 1; i <= data.block[0]; i++) values[i-1] = data.block[i]; return data.block[0]; }