Combine Z_AFTER_DEACTIVATE with UNKNOWN_Z_NO_RAISE (#20444)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/Configuration.h

  * the issues involved, don't use chamber PID until someone else verifies that your hardware works.
  */
 //#define PIDTEMPCHAMBER
-
 //#define CHAMBER_LIMIT_SWITCHING
 
 /**
 
 //#define NO_MOTION_BEFORE_HOMING // Inhibit movement until all axes have been homed. Also enable HOME_AFTER_DEACTIVATE for extra safety.
 //#define HOME_AFTER_DEACTIVATE   // Require rehoming after steppers are deactivated. Also enable NO_MOTION_BEFORE_HOMING for extra safety.
-//#define UNKNOWN_Z_NO_RAISE      // Don't raise Z (lower the bed) if Z is "unknown." For beds that fall when Z is powered off.
+
+/**
+ * Set Z_IDLE_HEIGHT if the Z-Axis moves on its own when steppers are disabled.
+ *  - Use a low value (i.e., Z_MIN_POS) if the nozzle falls down to the bed.
+ *  - Use a large value (i.e., Z_MAX_POS) if the bed falls down, away from the nozzle.
+ */
+//#define Z_IDLE_HEIGHT Z_HOME_POS
 
 //#define Z_HOMING_HEIGHT  4      // (mm) Minimal Z height before homing (G28) for Z clearance above the bed, clamps, ...
                                   // Be sure to have this much clearance over your Z_MAX_POS to prevent grinding.

Marlin/Configuration_adv.h

 #define DISABLE_INACTIVE_Z true  // Set 'false' if the nozzle could fall onto your printed part!
 #define DISABLE_INACTIVE_E true
 
-// If the Nozzle or Bed falls when the Z stepper is disabled, set its resting position here.
-//#define Z_AFTER_DEACTIVATE Z_HOME_POS
-
 // Default Minimum Feedrates for printing and travel moves
 #define DEFAULT_MINIMUMFEEDRATE       0.0     // (mm/s) Minimum feedrate. Set with M205 S.
 #define DEFAULT_MINTRAVELFEEDRATE     0.0     // (mm/s) Minimum travel feedrate. Set with M205 T.

Marlin/src/gcode/calibrate/G28.cpp

 
     #endif
 
-    const float z_homing_height = TERN1(UNKNOWN_Z_NO_RAISE, axis_is_trusted(Z_AXIS))
-                                  ? (parser.seenval('R') ? parser.value_linear_units() : Z_HOMING_HEIGHT)
-                                  : 0;
+    const float z_homing_height = parser.seenval('R') ? parser.value_linear_units() : Z_HOMING_HEIGHT;
 
     if (z_homing_height && (doX || doY || TERN0(Z_SAFE_HOMING, doZ))) {
       // Raise Z before homing any other axes and z is not already high enough (never lower z)
       if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPAIR("Raise Z (before homing) by ", z_homing_height);
-      do_z_clearance(z_homing_height, axis_is_trusted(Z_AXIS), DISABLED(UNKNOWN_Z_NO_RAISE));
+      do_z_clearance(z_homing_height);
     }
 
     #if ENABLED(QUICK_HOME)

Marlin/src/inc/SanityCheck.h

   #endif
 #elif defined(ASSISTED_TRAMMING_MENU_ITEM)
   #error "ASSISTED_TRAMMING_MENU_ITEM is deprecated and should be removed."
+#elif defined(UNKNOWN_Z_NO_RAISE)
+  #error "UNKNOWN_Z_NO_RAISE is replaced by setting Z_IDLE_HEIGHT to Z_MAX_POS."
+#elif defined(Z_AFTER_DEACTIVATE)
+  #error "Z_AFTER_DEACTIVATE is replaced by Z_IDLE_HEIGHT."
 #endif
 
 /**

Marlin/src/module/motion.cpp

  *   Used by 'line_to_current_position' to do a move after changing it.
  *   Used by 'sync_plan_position' to update 'planner.position'.
  */
-xyze_pos_t current_position = { X_HOME_POS, Y_HOME_POS, Z_HOME_POS };
+xyze_pos_t current_position = { X_HOME_POS, Y_HOME_POS,
+  #ifdef Z_IDLE_HEIGHT
+    Z_IDLE_HEIGHT
+  #else
+    Z_HOME_POS
+  #endif
+};
 
 /**
  * Cartesian Destination
   do_blocking_move_to(raw.x, raw.y, z, fr_mm_s);
 }
 
-void do_z_clearance(const float &zclear, const bool z_trusted/*=true*/, const bool raise_on_untrusted/*=true*/, const bool lower_allowed/*=false*/) {
-  const bool rel = raise_on_untrusted && !z_trusted;
-  float zdest = zclear + (rel ? current_position.z : 0.0f);
+void do_z_clearance(const float &zclear, const bool lower_allowed/*=false*/) {
+  float zdest = zclear;
   if (!lower_allowed) NOLESS(zdest, current_position.z);
   do_blocking_move_to_z(_MIN(zdest, Z_MAX_POS), TERN(HAS_BED_PROBE, z_probe_fast_mm_s, homing_feedrate(Z_AXIS)));
 }

Marlin/src/module/motion.h

 void remember_feedrate_scaling_off();
 void restore_feedrate_and_scaling();
 
-void do_z_clearance(const float &zclear, const bool z_trusted=true, const bool raise_on_untrusted=true, const bool lower_allowed=false);
+void do_z_clearance(const float &zclear, const bool lower_allowed=false);
 
 /**
  * Homing and Trusted Axes

Marlin/src/module/probe.cpp

     constexpr bool z_raise_wanted = true;
   #endif
 
-  // For beds that fall when Z is powered off only raise for trusted Z
-  #if ENABLED(UNKNOWN_Z_NO_RAISE)
-    const bool z_is_trusted = axis_is_trusted(Z_AXIS);
-  #else
-    constexpr float z_is_trusted = true;
-  #endif
-
-  if (z_is_trusted && z_raise_wanted)
+  if (z_raise_wanted)
     do_z_raise(_MAX(Z_CLEARANCE_BETWEEN_PROBES, Z_CLEARANCE_DEPLOY_PROBE));
 
   #if EITHER(Z_PROBE_SLED, Z_PROBE_ALLEN_KEY)

Marlin/src/module/probe.h

 
     static void move_z_after_probing() {
       #ifdef Z_AFTER_PROBING
-        do_z_clearance(Z_AFTER_PROBING, true, true, true); // Move down still permitted
+        do_z_clearance(Z_AFTER_PROBING, true); // Move down still permitted
       #endif
     }
     static float probe_at_point(const float &rx, const float &ry, const ProbePtRaise raise_after=PROBE_PT_NONE, const uint8_t verbose_level=0, const bool probe_relative=true, const bool sanity_check=true);
 
   static void move_z_after_homing() {
     #ifdef Z_AFTER_HOMING
-      do_z_clearance(Z_AFTER_HOMING, true, true, true);
+      do_z_clearance(Z_AFTER_HOMING, true);
     #elif BOTH(Z_AFTER_PROBING, HAS_BED_PROBE)
       move_z_after_probing();
     #endif

Marlin/src/module/stepper/indirection.h

 #define  ENABLE_AXIS_Z() if (SHOULD_ENABLE(z))  {  ENABLE_STEPPER_Z();  ENABLE_STEPPER_Z2();  ENABLE_STEPPER_Z3();  ENABLE_STEPPER_Z4(); AFTER_CHANGE(z, true); }
 #define DISABLE_AXIS_Z() if (SHOULD_DISABLE(z)) { DISABLE_STEPPER_Z(); DISABLE_STEPPER_Z2(); DISABLE_STEPPER_Z3(); DISABLE_STEPPER_Z4(); AFTER_CHANGE(z, false); set_axis_untrusted(Z_AXIS); Z_RESET(); }
 
-#ifdef Z_AFTER_DEACTIVATE
-  #define Z_RESET() do{ current_position.z = Z_AFTER_DEACTIVATE; sync_plan_position(); }while(0)
+#ifdef Z_IDLE_HEIGHT
+  #define Z_RESET() do{ current_position.z = Z_IDLE_HEIGHT; sync_plan_position(); }while(0)
 #else
   #define Z_RESET()
 #endif

buildroot/tests/STM32F103RC_btt-tests

 opt_set Y_DRIVER_TYPE TMC2209
 opt_set Z_DRIVER_TYPE TMC2209
 opt_set E0_DRIVER_TYPE TMC2209
-opt_enable PINS_DEBUGGING
+opt_enable PINS_DEBUGGING Z_IDLE_HEIGHT
 
 exec_test $1 $2 "BigTreeTech SKR Mini E3 1.0 - Basic Config with TMC2209 HW Serial" "$3"