adc: add support for multiple sensor voltage channels

msg/system_power.msg

@@ -1,7 +1,7 @@
 uint64 timestamp		# time since system start (microseconds)
 float32 voltage5v_v		# peripheral 5V rail voltage
-float32 voltage3v3_v		# Sensor 3V3 rail voltage
+float32[4] sensors3v3		# Sensors 3V3 rail voltage
-uint8 v3v3_valid		# Sensor 3V3 rail voltage was read.
+uint8 sensors3v3_valid		# Sensors 3V3 rail voltage was read (bitfield).
 uint8 usb_connected		# USB is connected when 1
 uint8 brick_valid		# brick bits power is good when bit 1
 uint8 usb_valid 		# USB is valid when 1

platforms/common/include/px4_platform_common/board_common.h

@@ -174,7 +174,19 @@
 /* Define the source for ADC_SCALED_V3V3_SENSORS_SENSE */
 
 #if defined(ADC_SCALED_VDD_3V3_SENSORS_CHANNEL)
-#  define ADC_SCALED_V3V3_SENSORS_SENSE ADC_SCALED_VDD_3V3_SENSORS_CHANNEL
+#  define ADC_SCALED_V3V3_SENSORS_SENSE { ADC_SCALED_VDD_3V3_SENSORS_CHANNEL }
+#  define ADC_SCALED_V3V3_SENSORS_COUNT 1
+#elif defined(ADC_SCALED_VDD_3V3_SENSORS4_CHANNEL)
+#  define ADC_SCALED_V3V3_SENSORS_SENSE { ADC_SCALED_VDD_3V3_SENSORS1_CHANNEL, ADC_SCALED_VDD_3V3_SENSORS2_CHANNEL, \
+		ADC_SCALED_VDD_3V3_SENSORS3_CHANNEL, ADC_SCALED_VDD_3V3_SENSORS4_CHANNEL }
+#  define ADC_SCALED_V3V3_SENSORS_COUNT 4
+#elif defined(ADC_SCALED_VDD_3V3_SENSORS3_CHANNEL)
+#  define ADC_SCALED_V3V3_SENSORS_SENSE { ADC_SCALED_VDD_3V3_SENSORS1_CHANNEL, ADC_SCALED_VDD_3V3_SENSORS2_CHANNEL, \
+		ADC_SCALED_VDD_3V3_SENSORS3_CHANNEL }
+#  define ADC_SCALED_V3V3_SENSORS_COUNT 3
+#elif defined(ADC_SCALED_VDD_3V3_SENSORS2_CHANNEL)
+#  define ADC_SCALED_V3V3_SENSORS_SENSE { ADC_SCALED_VDD_3V3_SENSORS1_CHANNEL, ADC_SCALED_VDD_3V3_SENSORS2_CHANNEL }
+#  define ADC_SCALED_V3V3_SENSORS_COUNT 2
 #endif
 
 /* Define an overridable default of 0.0f V for batery v div

src/drivers/adc/board_adc/ADC.cpp

@@ -198,7 +198,7 @@ void ADC::update_system_power(hrt_abstime now)
 	int cnt = 1;
 	/* HW provides both ADC_SCALED_V5_SENSE and ADC_SCALED_V3V3_SENSORS_SENSE */
 #  if defined(ADC_SCALED_V5_SENSE) && defined(ADC_SCALED_V3V3_SENSORS_SENSE)
-	cnt++;
+	cnt += ADC_SCALED_V3V3_SENSORS_COUNT;
 #  endif
 
 	for (unsigned i = 0; i < _channel_count; i++) {
@@ -213,11 +213,17 @@ void ADC::update_system_power(hrt_abstime now)
 #  endif
 #  if defined(ADC_SCALED_V3V3_SENSORS_SENSE)
 		{
-			if (_samples[i].am_channel == ADC_SCALED_V3V3_SENSORS_SENSE) {
+			const int sensors_channels[ADC_SCALED_V3V3_SENSORS_COUNT] = ADC_SCALED_V3V3_SENSORS_SENSE;
-				// it is 2:1 scaled
+			static_assert(sizeof(system_power.sensors3v3) / sizeof(system_power.sensors3v3[0]) >= ADC_SCALED_V3V3_SENSORS_COUNT,
-				system_power.voltage3v3_v = _samples[i].am_data * (ADC_3V3_SCALE * (3.3f / px4_arch_adc_dn_fullcount()));
+				      "array too small");
-				system_power.v3v3_valid = 1;
+
-				cnt--;
+			for (int j = 0; j < ADC_SCALED_V3V3_SENSORS_COUNT; ++j) {
+				if (_samples[i].am_channel == sensors_channels[j]) {
+					// it is 2:1 scaled
+					system_power.sensors3v3[j] = _samples[i].am_data * (ADC_3V3_SCALE * (3.3f / px4_arch_adc_dn_fullcount()));
+					system_power.sensors3v3_valid |= 1 << j;
+					cnt--;
+				}
 			}
 		}