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/*
smbus.c - SMBus level access helper functions
Copyright (C) 1995-1997 Simon G. Vogl
Copyright (C) 1998-1999 Frodo Looijaard <frodol@dds.nl>
Copyright (C) 2012-2013 Jean Delvare <jdelvare@suse.de>
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 <errno.h>
#include <stddef.h>
#include <i2c/smbus.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
/* 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];
}
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