Not all i2c devices can be read that way. There are several devices that require an address (on top of the device address) to be written before data can be rea

Not all i2c devices can be read that way. There are several devices that require an address (on top of the device address) to be written before data can be read, but without a second stop bit after writing the address. You end up with like double start condition. These require either using the smbus stuff or I2C_RDWR ioctl.