10.5 Iterating over an enum

[dermiem]

I usually define a enum in a project specific H file, to represent a set of signals:
typedef enum {
ADC_VBAT
ADC_FEEDBACK,
ADC_VOLTAGE,

ADC_NUM_SIGNALS
} adc_t ;

And then in the reusable C file, iterate over the configured set of signals. For example, to set the initial value of the averaged signal:

uint8_t i ;

for (i=0U; i < (uint8_t) ADC_NUM_SIGNALS; i++)
{
AdcClearAverage((adc_t) i) ;
}

where AdcClearAverage takes a parameter of type adc_t.

But this now generates warning 10.5 as an unsigned type is being cast to an enum.
What is the correct way to iterate over an enumeration?