Support for "mechanical probe" with Allen Key as a special case

Marlin/Conditionals.h

   #endif
 
   /**
+   * Enable MECHANICAL_PROBE for Z_PROBE_ALLEN_KEY, for older configs
+   */
+  #if ENABLED(Z_PROBE_ALLEN_KEY)
+    #define MECHANICAL_PROBE
+  #endif
+
+  /**
    * Avoid double-negatives for enabling features
    */
   #if DISABLED(DISABLE_HOST_KEEPALIVE)
   #if  ( (HAS_Z_MIN && ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN)) || HAS_Z_PROBE ) \
     && ( \
          ENABLED(FIX_MOUNTED_PROBE) \
+      || ENABLED(MECHANICAL_PROBE) \
       || HAS_Z_ENDSTOP_SERVO \
       || ENABLED(Z_PROBE_ALLEN_KEY) \
       || ENABLED(Z_PROBE_SLED) \

Marlin/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/Marlin_main.cpp

     #endif // Z_PROBE_ALLEN_KEY
 
     #if ENABLED(FIX_MOUNTED_PROBE)
-      // Noting to be done. Just set z_probe_is_active
+      // Nothing to do here. Just clear z_probe_is_active
     #endif
 
     z_probe_is_active = false;
 
     #if ENABLED(Z_PROBE_SLED)
       dock_sled(false); // engage (un-dock) the Z probe
-    #elif ENABLED(Z_PROBE_ALLEN_KEY) || (ENABLED(DELTA) && SERVO_LEVELING)
+    #elif ENABLED(MECHANICAL_PROBE) || (ENABLED(DELTA) && SERVO_LEVELING)
       deploy_z_probe();
     #endif
 
       #if ENABLED(Z_PROBE_ALLEN_KEY) || SERVO_LEVELING
         stow_z_probe();
       #elif Z_RAISE_AFTER_PROBING > 0
-        raise_z_after_probing(); // ???
+        raise_z_after_probing(); // for non Allen Key probes, such as simple mechanical probe
       #endif
     #else // !DELTA
       if (verbose_level > 0)

Marlin/SanityCheck.h

 /**
  * A probe needs a pin
  */
-#if (!((HAS_Z_MIN && ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN)) || HAS_Z_PROBE )) && ( ENABLED(FIX_MOUNTED_PROBE) || defined(Z_ENDSTOP_SERVO_NR) || ENABLED(Z_PROBE_ALLEN_KEY) || ENABLED(Z_PROBE_SLED))
+#if (!((HAS_Z_MIN && ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN)) || HAS_Z_PROBE )) && ( ENABLED(FIX_MOUNTED_PROBE) || defined(Z_ENDSTOP_SERVO_NR) || ENABLED(MECHANICAL_PROBE) || ENABLED(Z_PROBE_SLED))
   #error A probe needs a pin! [Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN || HAS_Z_PROBE]
 #endif
 
-#if ((HAS_Z_MIN && ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN)) && HAS_Z_PROBE) && ( ENABLED(FIX_MOUNTED_PROBE) || defined(Z_ENDSTOP_SERVO_NR) || ENABLED(Z_PROBE_ALLEN_KEY) || ENABLED(Z_PROBE_SLED))
+#if ((HAS_Z_MIN && ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN)) && HAS_Z_PROBE) && ( ENABLED(FIX_MOUNTED_PROBE) || defined(Z_ENDSTOP_SERVO_NR) || ENABLED(MECHANICAL_PROBE) || ENABLED(Z_PROBE_SLED))
   #error A probe should not be connected to more then one pin! [Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN || HAS_Z_PROBE]
 #endif
 
 /**
   * Require one kind of probe
   */
-#if ENABLED(AUTO_BED_LEVELING_FEATURE) && !( ENABLED(FIX_MOUNTED_PROBE) || defined(Z_ENDSTOP_SERVO_NR) || ENABLED(Z_PROBE_ALLEN_KEY) || ENABLED(Z_PROBE_SLED))
-  #error For AUTO_BED_LEVELING_FEATURE define one kind of probe! {Servo | Z_PROBE_ALLEN_KEY | Z_PROBE_SLED | FIX_MOUNTED_PROBE]
+#if ENABLED(AUTO_BED_LEVELING_FEATURE) && !( ENABLED(FIX_MOUNTED_PROBE) || defined(Z_ENDSTOP_SERVO_NR) || ENABLED(MECHANICAL_PROBE) || ENABLED(Z_PROBE_SLED))
+  #error For AUTO_BED_LEVELING_FEATURE define one kind of probe! [Servo | MECHANICAL_PROBE | Z_PROBE_SLED | FIX_MOUNTED_PROBE]
 #endif
 
-#if ENABLED(Z_SAFE_HOMING)&& !( ENABLED(FIX_MOUNTED_PROBE) || defined(Z_ENDSTOP_SERVO_NR) || ENABLED(Z_PROBE_ALLEN_KEY) || ENABLED(Z_PROBE_SLED))
-  #error For Z_SAFE_HOMING define one kind of probe! {Servo | Z_PROBE_ALLEN_KEY | Z_PROBE_SLED | FIX_MOUNTED_PROBE]
+#if ENABLED(Z_SAFE_HOMING)&& !( ENABLED(FIX_MOUNTED_PROBE) || defined(Z_ENDSTOP_SERVO_NR) || ENABLED(MECHANICAL_PROBE) || ENABLED(Z_PROBE_SLED))
+  #error For Z_SAFE_HOMING define one kind of probe! [Servo | MECHANICAL_PROBE | Z_PROBE_SLED | FIX_MOUNTED_PROBE]
 #endif
 
 // To do: Fail with more then one probe defined

Marlin/example_configurations/Felix/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/Felix/Configuration_DUAL.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/Hephestos/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/Hephestos_2/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/K8200/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/RepRapWorld/Megatronics/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/RigidBot/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/SCARA/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/TAZ4/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/WITBOX/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/adafruit/ST7565/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/delta/biv2.5/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-  // Allen key retractable Z probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
+  // Allen key retractable z-probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
   // Deploys by touching z-axis belt. Retracts by pushing the probe down. Uses Z_MIN_PIN.
   //#define Z_PROBE_ALLEN_KEY
 

Marlin/example_configurations/delta/generic/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-  // Allen key retractable Z probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
+  // Allen key retractable z-probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
   // Deploys by touching z-axis belt. Retracts by pushing the probe down. Uses Z_MIN_PIN.
   //#define Z_PROBE_ALLEN_KEY
 

Marlin/example_configurations/delta/kossel_mini/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-  // Allen key retractable Z probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
+  // Allen key retractable z-probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
   // Deploys by touching z-axis belt. Retracts by pushing the probe down. Uses Z_MIN_PIN.
   #define Z_PROBE_ALLEN_KEY
 

Marlin/example_configurations/delta/kossel_pro/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
-  // Allen key retractable Z probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
+  // Allen key retractable z-probe as seen on many Kossel delta printers - http://reprap.org/wiki/Kossel#Automatic_bed_leveling_probe
   // Deploys by touching z-axis belt. Retracts by pushing the probe down. Uses Z_MIN_PIN.
   #define Z_PROBE_ALLEN_KEY
 

Marlin/example_configurations/delta/kossel_xl/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/makibox/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!
 

Marlin/example_configurations/tvrrug/Round2/Configuration.h

   //#define Z_PROBE_SLED // Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
   //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+  // A Mechanical Probe is any probe that either doesn't deploy or needs manual deployment
+  // For example any setup that uses the nozzle itself as a probe.
+  //#define MECHANICAL_PROBE
+
   // If you've enabled AUTO_BED_LEVELING_FEATURE and are using the Z Probe for Z Homing,
   // it is highly recommended you leave Z_SAFE_HOMING enabled!