Why Is My AVR32UC ADC Returning Zero Despite a Correct Input Signal?

#include <zephyr.h>
#include <device.h>
#include <drivers/adc.h>

#define ADC_CHANNEL 1
#define ADC_DEV "ADC_0"

void main(void) {
    const struct device *adc_dev = device_get_binding(ADC_DEV);
    struct adc_sequence sequence = { .channels = BIT(ADC_CHANNEL) };
    adc_read(adc_dev, &sequence);
}

error: Failed to get binding for ADC device