homing: Base homing cpu delay on estimated number of steps needed

Instead of adding 250ms to each homing operation add a time relative
to the number of estimated steps that are to be generated.  This
scales the delay to really large axes without adding a delay for
normal users.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/homing.py

@@ -5,7 +5,7 @@
 # This file may be distributed under the terms of the GNU GPLv3 license.
 import logging
 
-HOMING_DELAY = 0.250
+HOMING_STEP_DELAY = 0.00000025
 ENDSTOP_SAMPLE_TIME = .000015
 ENDSTOP_SAMPLE_COUNT = 4
 
@@ -34,7 +34,13 @@ class Homing:
         self.toolhead.set_position(self._fill_coord(forcepos))
         # Start homing and issue move
         if not second_home:
-            self.toolhead.dwell(HOMING_DELAY)
+            est_move_d = sum([abs(forcepos[i]-movepos[i])
+                              for i in range(3) if movepos[i] is not None])
+            est_steps = sum(
+                [est_move_d / mcu_stepper.get_step_dist()
+                 for s in steppers
+                 for mcu_endstop, mcu_stepper, name in s.get_endstops()])
+            self.toolhead.dwell(est_steps * HOMING_STEP_DELAY, check_stall=False)
         print_time = self.toolhead.get_last_move_time()
         endstops = []
         for s in steppers:

klippy/toolhead.py

@@ -329,10 +329,11 @@ class ToolHead:
             self._check_stall()
     def home(self, homing_state):
         self.kin.home(homing_state)
-    def dwell(self, delay):
+    def dwell(self, delay, check_stall=True):
         self.get_last_move_time()
         self.update_move_time(delay)
-        self._check_stall()
+        if check_stall:
+            self._check_stall()
     def motor_off(self):
         self.dwell(STALL_TIME)
         last_move_time = self.get_last_move_time()