Signed-off-by: Matthias Fuchs <matthias.fuchs@esd-electronics.com>
        int ret_val = FPGA_FAIL;        /* assume the worst */
        Xilinx_Spartan2_Slave_Serial_fns *fn = desc->iface_fns;
        int i;
-       char  val;
+       unsigned char val;
 
        PRINTF ("%s: start with interface functions @ 0x%p\n",
                        __FUNCTION__, fn);
 
        int ret_val = FPGA_FAIL;        /* assume the worst */
        Xilinx_Spartan3_Slave_Serial_fns *fn = desc->iface_fns;
        int i;
-       char  val;
+       unsigned char val;
 
        PRINTF ("%s: start with interface functions @ 0x%p\n",
                        __FUNCTION__, fn);