RC_Channel: Aux switches to respect 'reverse' option

libraries/RC_Channel/RC_Channel.cpp

@@ -966,10 +966,14 @@ bool RC_Channel::read_3pos_switch(RC_Channel::aux_switch_pos_t &ret) const
     if (in <= 900 or in >= 2200) {
         return false;
     }
+    
+    // switch is reversed if 'reversed' option set on channel and switches reverse is allowed by RC_OPTIONS
+    bool switch_reversed = reversed && rc().switch_reverse_allowed();
+    
     if (in < AUX_PWM_TRIGGER_LOW) {
-        ret = LOW;
+        ret = switch_reversed ? HIGH : LOW;
     } else if (in > AUX_PWM_TRIGGER_HIGH) {
-        ret = HIGH;
+        ret = switch_reversed ? LOW : HIGH;
     } else {
         ret = MIDDLE;
     }

libraries/RC_Channel/RC_Channel.h

@@ -358,6 +358,11 @@ public:
         return get_singleton() != nullptr && (_options & uint32_t(Option::FPORT_PAD));
     }
 
+    // should a channel reverse option affect aux switches
+    bool switch_reverse_allowed(void) const {
+        return get_singleton() != nullptr && (_options & uint32_t(Option::ALLOW_SWITCH_REV));
+    }
+
     bool ignore_overrides() const {
         return _options & uint32_t(Option::IGNORE_OVERRIDES);
     }
@@ -381,7 +386,7 @@ public:
     float override_timeout_ms() const {
         return _override_timeout.get() * 1e3f;
     }
-
+    
     /*
       get the RC input PWM value given a channel number.  Note that
       channel numbers start at 1, as this API is designed for use in
@@ -401,6 +406,7 @@ protected:
         LOG_DATA              = (1 << 4), // log rc input bytes
         ARMING_CHECK_THROTTLE = (1 << 5), // run an arming check for neutral throttle
         ARMING_SKIP_CHECK_RPY = (1 << 6), // skip the an arming checks for the roll/pitch/yaw channels
+        ALLOW_SWITCH_REV      = (1 << 7), // honor the reversed flag on switches
     };
 
     void new_override_received() {

libraries/RC_Channel/RC_Channels_VarInfo.h

@@ -86,7 +86,7 @@ const AP_Param::GroupInfo RC_Channels::var_info[] = {
     // @DisplayName: RC options
     // @Description: RC input options
     // @User: Advanced
-    // @Bitmask: 0:Ignore RC Receiver, 1:Ignore MAVLink Overrides, 2:Ignore Receiver Failsafe, 3:FPort Pad, 4:Log RC input bytes, 5:Arming check throttle for 0 input, 6:Skip the arming check for neutral Roll/Pitch/Yay sticks
+    // @Bitmask: 0:Ignore RC Receiver, 1:Ignore MAVLink Overrides, 2:Ignore Receiver Failsafe, 3:FPort Pad, 4:Log RC input bytes, 5:Arming check throttle for 0 input, 6:Skip the arming check for neutral Roll/Pitch/Yay sticks, 7:Allow Switch reverse
     AP_GROUPINFO("_OPTIONS", 33, RC_CHANNELS_SUBCLASS, _options, 0),
 
     AP_GROUPEND