I have to work in a Project, but I not sure about this.
I think, It could be make with one, but to be sure can you tell me?.
If you plan to measure current and voltage, you need at least one ADC channel per each of those variables. Frequency is calculated from either of the current or voltage measurements (much easier based on the voltage).
The reference design in the link below has full information on how to implement a single-phase power meter. This should give you all the info you need:
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