How does uORB Topic adc_report for ADC 6.6 V channel in Pixhawk 1?

In the the file src\drivers\stm32\adc\adc.cpp at line no 372 FW version 1.8
the following code snippet
for (unsigned i = 0; i < max_num; i++) { adc.channel_id[i] = _samples[i].am_channel; adc.channel_value[i] = _samples[i].am_data * 3.3f / 4096.0f; }
converts the 12 bit read digital value to corresponding voltage value
Now I understand that a Pixhawk 1 board has both 3.3 V and 6.6 V port
So what I am unable to understand is how the above code snippet would work for a 6.6 V ADC port?
I am confused with this part
can anyone help me understand this?