inline uint16_t my_adc_start(uint32_t adc, uint32_t flags)
{
    ADC_CR(adc)=flags | ADC_CR_CLKDIV((uint8_t)(208/4.5))|ADC_CR_10BITS|ADC_CR_POWER|ADC_CR_START;
}

/* from libopencm3, we copy it here to have it inlined */
inline uint16_t my_adc_get_single(uint32_t adc, uint32_t flags)
{
    uint32_t result;

    do {
        result=ADC_GDR(adc);
    } while( (!ADC_DR_DONE(result)) );

    uint16_t adc_value = ADC_DR_VREF(result);

    my_adc_start(adc, flags);

    return adc_value;
};