fix(pmic): Properly disable AMUX when not in use

epicardium/modules/modules.h

@@ -52,6 +52,7 @@ void watchdog_clearer_init();
 #define BATTERY_CRITICAL   3.40f
 
 enum pmic_amux_signal {
+	PMIC_AMUX_DISABLED    = 0x0,
 	PMIC_AMUX_CHGIN_U     = 0x1,
 	PMIC_AMUX_CHGIN_I     = 0x2,
 	PMIC_AMUX_BATT_U      = 0x3,

epicardium/modules/pmic.c

@@ -86,7 +86,7 @@ int pmic_read_amux(enum pmic_amux_signal sig, float *result)
 	ADC_GetData(&adc_data);
 
 	/* Turn MUX back to neutral so it does not waste power.  */
-	MAX77650_setMUX_SEL(sig);
+	MAX77650_setMUX_SEL(PMIC_AMUX_DISABLED);
 
 	/* Convert ADC measurement to SI Volts */
 	float adc_voltage = (float)adc_data / 1023.0f * 1.22f;