This fixes the problem that `adc_raw_to_millivolts` only returns half of
the actual voltage.
Signed-off-by: Caspar Friedrich <c.s.w.friedrich@gmail.com>
This adds a driver for Texas Instruments Cost-Optimized, Ultra-Small,
12-Bit, System-Monitoring ADCs. Currently only TLA2021 is supported,
TLA2022 and TLA2024 may follow based on this driver.
Signed-off-by: Caspar Friedrich <c.s.w.friedrich@gmail.com>