Changed behavior of PR #1233 and doc update

Stick channels only have AUTO and HOLD mode.
AUX channels only have SET and HOLD mode.
Added check to parameter in CLI.
Modified rx.md to reflect changes (and more).

+1 squashed commit:

- A cleaner approach for the same functionality

Basically addressing all comments from Hydra

src/main/config/config.c

@@ -407,8 +407,8 @@ static void resetConf(void)
 
     for (i = 0; i < MAX_SUPPORTED_RC_CHANNEL_COUNT; i++) {
         rxFailsafeChannelConfiguration_t *channelFailsafeConfiguration = &masterConfig.rxConfig.failsafe_channel_configurations[i];
-        channelFailsafeConfiguration->mode = RX_FAILSAFE_MODE_AUTO;
-        channelFailsafeConfiguration->step = CHANNEL_VALUE_TO_RXFAIL_STEP(masterConfig.rxConfig.midrc);
+        channelFailsafeConfiguration->mode = (i < NON_AUX_CHANNEL_COUNT) ? RX_FAILSAFE_MODE_AUTO : RX_FAILSAFE_MODE_HOLD;
+        channelFailsafeConfiguration->step = (i == THROTTLE) ? masterConfig.rxConfig.rx_min_usec : CHANNEL_VALUE_TO_RXFAIL_STEP(masterConfig.rxConfig.midrc);
     }
 
     masterConfig.rxConfig.rssi_channel = 0;

src/main/io/serial_cli.c

@@ -170,7 +170,12 @@ static const char * const featureNames[] = {
 };
 
 // sync this with rxFailsafeChannelMode_e
-static char rxFailsafeModes[RX_FAILSAFE_MODE_COUNT] = { 'a', 'h', 's'};
+static const char rxFailsafeModeCharacters[] = "ahs";
+
+static const rxFailsafeChannelMode_e rxFailsafeModesTable[RX_FAILSAFE_TYPE_COUNT][RX_FAILSAFE_MODE_COUNT] = {
+    { RX_FAILSAFE_MODE_AUTO, RX_FAILSAFE_MODE_HOLD, RX_FAILSAFE_MODE_INVALID },
+    { RX_FAILSAFE_MODE_INVALID, RX_FAILSAFE_MODE_HOLD, RX_FAILSAFE_MODE_SET }
+};
 
 #ifndef CJMCU
 // sync this with sensors_e
@@ -587,27 +592,22 @@ static void cliRxFail(char *cmdline)
             rxFailsafeChannelConfiguration_t *channelFailsafeConfiguration = &masterConfig.rxConfig.failsafe_channel_configurations[channel];
 
             uint16_t value;
+            rxFailsafeChannelType_e type = (channel < NON_AUX_CHANNEL_COUNT) ? RX_FAILSAFE_TYPE_FLIGHT : RX_FAILSAFE_TYPE_AUX;
             rxFailsafeChannelMode_e mode = channelFailsafeConfiguration->mode;
             bool requireValue = channelFailsafeConfiguration->mode == RX_FAILSAFE_MODE_SET;
 
-            // TODO optimize to use rxFailsafeModes - less logic.
             ptr = strchr(ptr, ' ');
             if (ptr) {
-                switch (*(++ptr)) {
-                    case 'a':
-                        mode = RX_FAILSAFE_MODE_AUTO;
-                        break;
-
-                    case 'h':
-                        mode = RX_FAILSAFE_MODE_HOLD;
-                        break;
-
-                    case 's':
-                        mode = RX_FAILSAFE_MODE_SET;
-                        break;
-                    default:
-                        cliShowParseError();
-                        return;
+                char *p = strchr(rxFailsafeModeCharacters, *(++ptr));
+                if (p) {
+                    uint8_t requestedMode = p - rxFailsafeModeCharacters;
+                    mode = rxFailsafeModesTable[type][requestedMode];
+                } else {
+                    mode = RX_FAILSAFE_MODE_INVALID;
+                }
+                if (mode == RX_FAILSAFE_MODE_INVALID) {
+                    cliShowParseError();
+                    return;
                 }
 
                 requireValue = mode == RX_FAILSAFE_MODE_SET;
@@ -626,12 +626,15 @@ static void cliRxFail(char *cmdline)
                     }
 
                     channelFailsafeConfiguration->step = value;
+                } else if (requireValue) {
+                    cliShowParseError();
+                    return;
                 }
                 channelFailsafeConfiguration->mode = mode;
 
             }
 
-            char modeCharacter = rxFailsafeModes[channelFailsafeConfiguration->mode];
+            char modeCharacter = rxFailsafeModeCharacters[channelFailsafeConfiguration->mode];
 
             // triple use of printf below
             // 1. acknowledge interpretation on command,

src/main/rx/rx.c

@@ -346,27 +346,29 @@ static uint16_t getRxfailValue(uint8_t channel)
     rxFailsafeChannelConfiguration_t *channelFailsafeConfiguration = &rxConfig->failsafe_channel_configurations[channel];
 
     switch(channelFailsafeConfiguration->mode) {
-        default:
         case RX_FAILSAFE_MODE_AUTO:
             switch (channel) {
                 case ROLL:
                 case PITCH:
                 case YAW:
                     return rxConfig->midrc;
+
                 case THROTTLE:
                     if (feature(FEATURE_3D))
                         return rxConfig->midrc;
                     else
                         return rxConfig->rx_min_usec;
             }
-            // fall though to HOLD if there's nothing specific to do.
+            /* no break */
+
+        default:
+        case RX_FAILSAFE_MODE_INVALID:
         case RX_FAILSAFE_MODE_HOLD:
             return rcData[channel];
 
         case RX_FAILSAFE_MODE_SET:
             return RXFAIL_STEP_TO_CHANNEL_VALUE(channelFailsafeConfiguration->step);
     }
-
 }
 
 STATIC_UNIT_TESTED uint16_t applyRxChannelRangeConfiguraton(int sample, rxChannelRangeConfiguration_t range)

src/main/rx/rx.h

@@ -85,10 +85,18 @@ typedef enum {
     RX_FAILSAFE_MODE_AUTO = 0,
     RX_FAILSAFE_MODE_HOLD,
     RX_FAILSAFE_MODE_SET,
+    RX_FAILSAFE_MODE_INVALID,
 } rxFailsafeChannelMode_e;
 
 #define RX_FAILSAFE_MODE_COUNT 3
 
+typedef enum {
+    RX_FAILSAFE_TYPE_FLIGHT = 0,
+    RX_FAILSAFE_TYPE_AUX,
+} rxFailsafeChannelType_e;
+
+#define RX_FAILSAFE_TYPE_COUNT 2
+
 typedef struct rxFailsafeChannelConfiguration_s {
     uint8_t mode; // See rxFailsafeChannelMode_e
     uint8_t step;