The ADC v2 peripheral doesn't have the same behaviour of starting, where
the hardware clears the bit immediately, on v2, it is not cleared until
the ADC is stopped, or the end of sequence flag is set.
Fixes https://github.com/libopencm3/libopencm3/issues/557
Extract the calibration code from the f0, and share it with the other
adc-v2 peripheral users (f0,l0,f3,l4)
Uses the same naming set of is/async naming conventions requested by the
RTOS guys instead of having blocking only calls.
Old code:
adc_calibrate_start(ADC);
adc_calibrate_wait_finish(ADC);
New code (blocking):
adc_calibrate(ADC);
New code (asynch):
adc_calibrate_async(ADC);
// do stuff
adc_is_calibrating(ADC); // will be false when it's finished.
Old code for f0 is still available, but marked deprecated.
The f0, f30x and l0 have a very similar "v2" adc peripheral.
Start extracting out some of the common code, and fix the glaring bug in
adc_power_down that was affecting them both.
This is not intended to be a fully comprehensive extraction, just the first
easy steps.
