HAL_ChibiOS: fixed RSSI voltage from IOMCU

libraries/AP_HAL_ChibiOS/AnalogIn.cpp

@@ -51,6 +51,9 @@ extern const AP_HAL::HAL& hal;
 
 using namespace ChibiOS;
 
+// special pins
+#define ANALOG_SERVO_VRSSI_PIN 103
+
 /*
   scaling table between ADC count and actual input voltage, to account
   for voltage dividers on the board. 
@@ -183,13 +186,6 @@ void AnalogSource::_add_value(float v, float vcc5V)
 }
 
 
-AnalogIn::AnalogIn() :
-    _board_voltage(0),
-    _servorail_voltage(0),
-    _power_flags(0)
-{
-}
-
 /*
   callback from ADC driver when sample buffer is filled
  */
@@ -290,24 +286,30 @@ void AnalogIn::_timer_tick(void)
         }
 #endif
     }
+
+#if HAL_WITH_IO_MCU
+    // now handle special inputs from IOMCU
+    _servorail_voltage = iomcu.get_vservo();
+    _rssi_voltage = iomcu.get_vrssi();
+#endif
+    
     for (uint8_t i=0; i<ADC_GRP1_NUM_CHANNELS; i++) {
         Debug("chan %u value=%u\n",
               (unsigned)pin_config[i].channel,
               (unsigned)buf_adc[i]);
         for (uint8_t j=0; j < ANALOG_MAX_CHANNELS; j++) {
             ChibiOS::AnalogSource *c = _channels[j];
-            if (c != nullptr && pin_config[i].channel == c->_pin) {
-                // add a value
-                c->_add_value(buf_adc[i], _board_voltage);
+            if (c != nullptr) {
+                if (pin_config[i].channel == c->_pin) {
+                    // add a value
+                    c->_add_value(buf_adc[i], _board_voltage);
+                } else if (c->_pin == ANALOG_SERVO_VRSSI_PIN) {
+                    c->_add_value(_rssi_voltage / VOLTAGE_SCALING, 0);
+                }
             }
         }
     }
 
-#if HAL_WITH_IO_MCU
-    // now handle special inputs from IOMCU
-    _servorail_voltage = iomcu.get_vservo();
-#endif
-
 #if CHIBIOS_ADC_MAVLINK_DEBUG
     static uint8_t count;
     if (AP_HAL::millis() > 5000 && count++ == 10) {

libraries/AP_HAL_ChibiOS/AnalogIn.h

@@ -57,7 +57,6 @@ class ChibiOS::AnalogIn : public AP_HAL::AnalogIn {
 public:
     friend class AnalogSource;
     
-    AnalogIn();
     void init() override;
     AP_HAL::AnalogSource* channel(int16_t pin) override;
     void _timer_tick(void);
@@ -80,6 +79,7 @@ private:
     uint32_t _last_run;
     float _board_voltage;
     float _servorail_voltage;
+    float _rssi_voltage;
     uint16_t _power_flags;
     ADCConversionGroup adcgrpcfg;