These routines read and write some bytes from/to a client. The client
contains the i2c address, so you do not have to include it. The second
parameter contains the bytes to read/write, the third the number of bytes
-to read/write (must be less than the length of the buffer.) Returned is
-the actual number of bytes read/written.
+to read/write (must be less than the length of the buffer, also should be
+less than 64k since msg.len is u16.) Returned is the actual number of bytes
+read/written.
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msg,
int num);