Writing USB Joystick for PIC18F using MikroC

void select_channel(int channel)
{
     if ( channel == 1 )
    {
      ADCON0.CHS0 = 0x1;
      ADCON0.CHS2 = 0x0;
      ADCON0.CHS1 = 0x0;
      ADCON0.CHS3 = 0x0;
    }
    else if (channel == 8)
    {
      ADCON0.CHS0 = 0x0;
      ADCON0.CHS2 = 0x0;
      ADCON0.CHS1 = 0x0;
      ADCON0.CHS3 = 0x1;
    }
    else
    {
      ADCON0.CHS0 = 0x1;
      ADCON0.CHS2 = 0x0;
      ADCON0.CHS1 = 0x0;
      ADCON0.CHS3 = 0x1;
    }

}
unsigned int ADC_read_implementation(int channel){

    unsigned int adval = 0;
    ADCON2.B7 = 1; //results right justified
    ADCON2.B0 = 0;
    ADCON2.B1 = 1;
    ADCON2.B2 = 1;
  
    ADCON2.B3 = 1;
    ADCON2.B4 = 0;
    ADCON2.B5 = 1;

    ADCON1 = 0x05;

    ADCON0.B0 = 1; //turn on ADC

    ADCON0.GO_DONE = 1;
    while(ADCON0.GO_DONE == 1);
    adval = (ADRESH << 8) + ADRESL;

    return adval;
}


     select_channel(1)
     Delay_ms(5);
     usb[0] = (char)ADC_read_implementation();
     select_channel(8)
     Delay_ms(5);

     usb[1] = (char)ADC_read_implementation();
     select_channel(9)
     Delay_ms(5);
     usb[2] = (char)ADC_read_implementation();