iio: adc: stm32: add support for differential channels
STM32H7 ADC channels can be configured either as single ended or
differential with 'st,adc-channels' or 'st,adc-diff-channels'
(positive and negative input pair: <vinp vinn>, ...).
Differential channels have different offset and scale, from spec:
raw value = (full_scale / 2) * (1 + (vinp - vinn) / vref).
Add offset attribute.
Differential channels are selected by DIFSEL register. Negative
inputs must be added to pre-selected channels as well (PCSEL).
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
1 file changed