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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 "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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