homing_override: Add axes config parameter

Added a config parameter to define the homing override axes. This way
one can still home x and y axis without the z-probe cycle coming in the
way.

Signed-off-by: Hans Raaf <hr-klipper@oderwat.de>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example-extras.cfg

@@ -486,10 +486,16 @@
 #[homing_override]
 #gcode:
 #   A list of G-Code commands (one per line) to execute in place of
-#   all G28 commands found in the normal g-code input. If a G28 is
+#   G28 commands found in the normal g-code input. If a G28 is
 #   contained in this list of commands then it will invoke the normal
 #   homing procedure for the printer. The commands listed here must
 #   home all axes. This parameter must be provided.
+#axes: xyz
+#   The axes to override. For example, if this is set to "z" then the
+#   override script will only be run when the z axis is homed (eg, via
+#   a "G28" or "G28 Z0" command). Note, the override script should
+#   still home all axes. The default is "xyz" which causes the
+#   override script to be run in place of all G28 commands.
 #set_position_x:
 #set_position_y:
 #set_position_z:

klippy/extras/homing_override.py

@@ -9,6 +9,7 @@ class HomingOverride:
         self.printer = config.get_printer()
         self.start_pos = [config.getfloat('set_position_' + a, None)
                           for a in 'xyz']
+        self.axes = config.get('axes', 'XYZ').upper()
         self.script = config.get('gcode')
         self.in_script = False
         self.gcode = self.printer.lookup_object('gcode')
@@ -19,6 +20,27 @@ class HomingOverride:
             # Was called recursively - invoke the real G28 command
             self.gcode.cmd_G28(params)
             return
+
+        # if no axis is given as parameter we assume the override
+        no_axis = True
+        for axis in 'XYZ':
+            if axis in params:
+                no_axis = False
+                break
+
+        if no_axis:
+            override = True
+        else:
+            # check if we home an axsis which needs the override
+            override = False
+            for axis in self.axes:
+                if axis in params:
+                    override = True
+
+        if not override:
+            self.gcode.cmd_G28(params)
+            return
+
         # Calculate forced position (if configured)
         toolhead = self.printer.lookup_object('toolhead')
         pos = toolhead.get_position()