i2c_smbus_write_byte_data(9) centos man page | unix.com

I2C_SMBUS_WRITE_BYTE(9) 				      I2C and SMBus Subsystem					   I2C_SMBUS_WRITE_BYTE(9)

NAME
       i2c_smbus_write_byte_data - SMBus "write byte" protocol

SYNOPSIS
       s32 i2c_smbus_write_byte_data(const struct i2c_client * client, u8 command, u8 value);

ARGUMENTS
       client
	   Handle to slave device

       command
	   Byte interpreted by slave

       value
	   Byte being written

DESCRIPTION
       This executes the SMBus "write byte" protocol, returning negative errno else zero on success.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						   I2C_SMBUS_WRITE_BYTE(9)