stepper: Add support for stepping on both edges of a step pulse

Add an optimized step function for drivers that support stepping on
both rising and falling edges of the step pin.  Enable this
optimization on 32bit ARM micro-controllers.  Automatically detect
this capability in the host code and enable on TMC drivers running in
SPI/UART mode.

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

1 files changed, 15 insertions, 1 deletions

diff --git a/klippy/stepper.py b/klippy/stepper.py
index c5f81382..2e6655ef 100644
--- a/klippy/stepper.py
+++ b/klippy/stepper.py
@@ -32,6 +32,7 @@ class MCU_stepper:
                 "Stepper dir pin must be on same mcu as step pin")
         self._dir_pin = dir_pin_params['pin']
         self._invert_dir = dir_pin_params['invert']
+        self._step_both_edge = self._req_step_both_edge = False
         self._mcu_position_offset = 0.
         self._reset_cmd_tag = self._get_position_cmd = None
         self._active_callbacks = []
@@ -54,6 +55,12 @@ class MCU_stepper:
     def units_in_radians(self):
         # Returns true if distances are in radians instead of millimeters
         return self._units_in_radians
+    def get_pulse_duration(self):
+        return self._step_pulse_duration, self._step_both_edge
+    def setup_default_pulse_duration(self, pulse_duration, step_both_edge):
+        if self._step_pulse_duration is None:
+            self._step_pulse_duration = pulse_duration
+        self._req_step_both_edge = step_both_edge
     def setup_itersolve(self, alloc_func, *params):
         ffi_main, ffi_lib = chelper.get_ffi()
         sk = ffi_main.gc(getattr(ffi_lib, alloc_func)(*params), ffi_lib.free)
@@ -61,11 +68,18 @@ class MCU_stepper:
     def _build_config(self):
         if self._step_pulse_duration is None:
             self._step_pulse_duration = .000002
+        invert_step = self._invert_step
+        sbe = int(self._mcu.get_constants().get('STEPPER_BOTH_EDGE', '0'))
+        if self._req_step_both_edge and sbe:
+            # Enable stepper optimized step on both edges
+            self._step_both_edge = True
+            self._step_pulse_duration = 0.
+            invert_step = -1
         step_pulse_ticks = self._mcu.seconds_to_clock(self._step_pulse_duration)
         self._mcu.add_config_cmd(
             "config_stepper oid=%d step_pin=%s dir_pin=%s invert_step=%d"
             " step_pulse_ticks=%u" % (self._oid, self._step_pin, self._dir_pin,
-                                      self._invert_step, step_pulse_ticks))
+                                      invert_step, step_pulse_ticks))
         self._mcu.add_config_cmd("reset_step_clock oid=%d clock=0"
                                  % (self._oid,), on_restart=True)
         step_cmd_tag = self._mcu.lookup_command_tag(