Accessing the client

Serial bus transactions are just a matter of accessing registers to set/get their content. I2C respects that principle. I2C core provides two kinds of API, one for plain I2C communications, and another for SMBUS-compatible devices, which also works with I2C devices, but not the reverse.

Plain I2C communication

The following are essential functions you usually deal with when talking to I2C devices:

int i2c_master_send(struct i2c_client *client, const char *buf, int count); 
int i2c_master_recv(struct i2c_client *client, char *buf, int count); 

Almost all I2C communication functions take a struct i2c_client as the first parameter. The second parameter contains the bytes to read or write and the third represents...