* size : the number of frames, each one having the configured data width (4 to 16 bits).
* data_out : data to be sent. Data will be read in the lower bits of the 16 bits values
* pointed by "data_out" for each frame. If NULL, then the content of data_in
- will be used.
+ * will be used.
* data_in : buffer for read data. If NULL, read data will be discarded.
* Returns the number of data words transfered or negative value on error.
* As the SPI bus is full duplex, data can flow in both directions, but the clock is