The ADC on exynos7 is quite similar to ADCv2. The differences are as
follows:
- exynos7-adc has 8 input channels (as against 10 in ADCv2).
- exynos7 does not include an ADC PHY control register.
- Some ADC_CON2 register bits being used in ADCv2 are listed as
reserved in exynos7-adc. This results in a different init_hw
function for exynos7.