int ftdi_read_data_set_chunksize(struct ftdi_context *ftdi, unsigned int chunksize);
int ftdi_read_data_get_chunksize(struct ftdi_context *ftdi, unsigned int *chunksize);
- int ftdi_write_data(struct ftdi_context *ftdi, unsigned char *buf, int size);
+ int ftdi_write_data(struct ftdi_context *ftdi, const unsigned char *buf, int size);
int ftdi_write_data_set_chunksize(struct ftdi_context *ftdi, unsigned int chunksize);
int ftdi_write_data_get_chunksize(struct ftdi_context *ftdi, unsigned int *chunksize);