Fix and extend BLTouch support

Marlin/Conditionals_LCD.h

 
   /**
    * The BLTouch Probe emulates a servo probe
+   * and uses "special" angles for its state.
    */
   #if ENABLED(BLTOUCH)
     #ifndef Z_ENDSTOP_SERVO_NR
     #ifndef NUM_SERVOS
       #define NUM_SERVOS (Z_ENDSTOP_SERVO_NR + 1)
     #endif
-    #undef Z_SERVO_ANGLES
-    #define Z_SERVO_ANGLES {10,90} // For BLTouch 10=deploy, 90=retract
     #undef DEACTIVATE_SERVOS_AFTER_MOVE
+    #undef Z_SERVO_ANGLES
+    #define Z_SERVO_ANGLES { BLTOUCH_DEPLOY, BLTOUCH_STOW }
+
+    #define BLTOUCH_DEPLOY    10
+    #define BLTOUCH_STOW   90
+    #define BLTOUCH_SELFTEST 120
+    #define BLTOUCH_RELEASE  160
+    #define _TEST_BLTOUCH(P) (READ(P##_PIN) != P##_ENDSTOP_INVERTING)
+
     #if ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN)
       #undef Z_MIN_ENDSTOP_INVERTING
       #define Z_MIN_ENDSTOP_INVERTING false
+      #define TEST_BLTOUCH() _TEST_BLTOUCH(Z_MIN)
+    #else
+      #define TEST_BLTOUCH() _TEST_BLTOUCH(Z_MIN_PROBE)
     #endif
   #endif
 

Marlin/Marlin_main.cpp

 
     // Check BLTOUCH probe status for an error
     #if ENABLED(BLTOUCH)
-      if (servo[Z_ENDSTOP_SERVO_NR].read() == BLTouchState_Error) { stop(); return true; }
+      if (TEST_BLTOUCH()) { stop(); return true; }
     #endif
 
     #if ENABLED(Z_PROBE_SLED)

Marlin/enum.h

   };
 #endif
 
-#if ENABLED(BLTOUCH)
-  enum BLTouchState {
-    BLTouchState_Deploy   = 10,
-    BLTouchState_Stow     = 90,
-    BLTouchState_Selftest = 120,
-    BLTouchState_Error    = 160
-  };
-#endif
-
 #if ENABLED(FILAMENT_CHANGE_FEATURE)
   enum FilamentChangeMenuResponse {
     FILAMENT_CHANGE_RESPONSE_WAIT_FOR,

Marlin/language_en.h

 #ifndef MSG_ZPROBE_OUT
   #define MSG_ZPROBE_OUT                      "Z probe out. bed"
 #endif
-#ifndef MSG_RESET_BLTOUCH
-  #define MSG_RESET_BLTOUCH                   "Reset BLTouch"
+#ifndef MSG_BLTOUCH_RESET
+  #define MSG_BLTOUCH_SELFTEST                "BLTouch Self-Test"
+#endif
+#ifndef MSG_BLTOUCH_RESET
+  #define MSG_BLTOUCH_RESET                   "Reset BLTouch"
 #endif
 #ifndef MSG_HOME
   #define MSG_HOME                            "Home"  // Used as MSG_HOME " " MSG_X MSG_Y MSG_Z " " MSG_FIRST

Marlin/ultralcd.cpp

 #include "utility.h"
 
 #if ENABLED(BLTOUCH)
-  #include "servo.h"
-  extern Servo servo[NUM_SERVOS];
+  #include "endstops.h"
 #endif
 
 #if ENABLED(PRINTCOUNTER)
     MENU_ITEM(back, MSG_WATCH);
 
     #if ENABLED(BLTOUCH)
-      if (servo[Z_ENDSTOP_SERVO_NR].read() == BLTouchState_Error)
-        MENU_ITEM(gcode, MSG_RESET_BLTOUCH, "M280 S90 P" STRINGIFY(Z_ENDSTOP_SERVO_NR));
+      if (!endstops.z_probe_enabled && TEST_BLTOUCH())
+        MENU_ITEM(gcode, MSG_BLTOUCH_RESET, PSTR("M280 P" STRINGIFY(Z_ENDSTOP_SERVO_NR) " S" STRINGIFY(BLTOUCH_RESET)));
     #endif
 
     if (planner.movesplanned() || IS_SD_PRINTING) {
     MENU_ITEM(function, MSG_COOLDOWN, lcd_cooldown);
 
     //
+    // BLTouch Self-Test and Reset
+    //
+    #if ENABLED(BLTOUCH)
+      MENU_ITEM(gcode, MSG_BLTOUCH_TEST, PSTR("M280 P" STRINGIFY(Z_ENDSTOP_SERVO_NR) " S" STRINGIFY(BLTOUCH_SELFTEST)));
+      if (!endstops.z_probe_enabled && TEST_BLTOUCH())
+        MENU_ITEM(gcode, MSG_BLTOUCH_RESET, PSTR("M280 P" STRINGIFY(Z_ENDSTOP_SERVO_NR) " S" STRINGIFY(BLTOUCH_RESET)));
+    #endif
+
+    //
     // Switch power on/off
     //
     #if HAS_POWER_SWITCH