Report on M92 with no arguments (#12833)

Marlin/src/gcode/config/M92.cpp

 #include "../gcode.h"
 #include "../../module/planner.h"
 
+void report_M92(
+  #if NUM_SERIAL > 1
+    const int8_t port,
+  #endif
+  const bool echo=true, const int8_t e=-1
+) {
+  if (echo) SERIAL_ECHO_START_P(port); else SERIAL_CHAR(' ');
+  SERIAL_ECHOPAIR_P(port, " M92 X", LINEAR_UNIT(planner.settings.axis_steps_per_mm[X_AXIS]));
+  SERIAL_ECHOPAIR_P(port, " Y", LINEAR_UNIT(planner.settings.axis_steps_per_mm[Y_AXIS]));
+  SERIAL_ECHOPAIR_P(port, " Z", LINEAR_UNIT(planner.settings.axis_steps_per_mm[Z_AXIS]));
+  #if DISABLED(DISTINCT_E_FACTORS)
+    SERIAL_ECHOPAIR_P(port, " E", VOLUMETRIC_UNIT(planner.settings.axis_steps_per_mm[E_AXIS]));
+  #endif
+  SERIAL_EOL_P(port);
+
+  #if ENABLED(DISTINCT_E_FACTORS)
+    for (uint8_t i = 0; i < E_STEPPERS; i++) {
+      if (e >= 0 && i != e) continue;
+      if (echo) SERIAL_ECHO_START_P(port); else SERIAL_CHAR(' ');
+      SERIAL_ECHOPAIR_P(port, " M92 T", (int)i);
+      SERIAL_ECHOLNPAIR_P(port, " E", VOLUMETRIC_UNIT(planner.settings.axis_steps_per_mm[E_AXIS_N(i)]));
+    }
+  #endif
+}
+
 /**
  * M92: Set axis steps-per-unit for one or more axes, X, Y, Z, and E.
  *      (Follows the same syntax as G92)
  *
  *      With multiple extruders use T to specify which one.
+ *
+ *      If no argument is given print the current values.
+ *
+ *    With MAGIC_NUMBERS_GCODE:
+ *      Use 'H' and/or 'L' to get ideal layer-height information.
+ *      'H' specifies micro-steps to use. We guess if it's not supplied.
+ *      'L' specifies a desired layer height. Nearest good heights are shown.
  */
 void GcodeSuite::M92() {
 
   const int8_t target_extruder = get_target_extruder_from_command();
   if (target_extruder < 0) return;
 
+  // No arguments? Show M92 report.
+  if (!parser.seen("XYZE"
+    #if ENABLED(MAGIC_NUMBERS_GCODE)
+      "HL"
+    #endif
+  )) return report_M92(
+    #if NUM_SERIAL > 1
+      command_queue_port[cmd_queue_index_r],
+    #endif
+    true, target_extruder
+  );
+
   LOOP_XYZE(i) {
-    if (parser.seen(axis_codes[i])) {
+    if (parser.seenval(axis_codes[i])) {
       if (i == E_AXIS) {
         const float value = parser.value_per_axis_units((AxisEnum)(E_AXIS_N(target_extruder)));
         if (value < 20) {
     }
   }
   planner.refresh_positioning();
+
+  #if ENABLED(MAGIC_NUMBERS_GCODE)
+    #ifndef Z_MICROSTEPS
+      #define Z_MICROSTEPS 16
+    #endif
+    const float wanted = parser.floatval('L');
+    if (parser.seen('H') || wanted) {
+      const uint16_t argH = parser.ushortval('H'),
+                     micro_steps = argH ? argH : Z_MICROSTEPS;
+      const float z_full_step_mm = micro_steps * planner.steps_to_mm[Z_AXIS];
+      SERIAL_ECHO_START();
+      SERIAL_ECHOPAIR("{ micro_steps:", micro_steps);
+      SERIAL_ECHOPAIR(", z_full_step_mm:", z_full_step_mm);
+      if (wanted) {
+        const float best = uint16_t(wanted / z_full_step_mm) * z_full_step_mm;
+        SERIAL_ECHOPGM(", best:[");
+        SERIAL_ECHO(best);
+        if (best != wanted) { SERIAL_CHAR(','); SERIAL_ECHO(best + z_full_step_mm); }
+        SERIAL_CHAR(']');
+      }
+      SERIAL_ECHOLNPGM(" }");
+    }
+  #endif
 }

Marlin/src/module/configuration_store.cpp

     #define SAY_UNITS_P(PORT, COLON) say_units(COLON)
   #endif
 
+  void report_M92(
+    #if NUM_SERIAL > 1
+      const int8_t port,
+    #endif
+    const bool echo=true, const int8_t e=-1
+  );
+
   /**
    * M503 - Report current settings in RAM
    *
     #endif // !NO_VOLUMETRICS
 
     CONFIG_ECHO_HEADING("Steps per unit:");
-    CONFIG_ECHO_START();
-    SERIAL_ECHOPAIR_P(port, "  M92 X", LINEAR_UNIT(planner.settings.axis_steps_per_mm[X_AXIS]));
-    SERIAL_ECHOPAIR_P(port, " Y", LINEAR_UNIT(planner.settings.axis_steps_per_mm[Y_AXIS]));
-    SERIAL_ECHOPAIR_P(port, " Z", LINEAR_UNIT(planner.settings.axis_steps_per_mm[Z_AXIS]));
-    #if DISABLED(DISTINCT_E_FACTORS)
-      SERIAL_ECHOPAIR_P(port, " E", VOLUMETRIC_UNIT(planner.settings.axis_steps_per_mm[E_AXIS]));
-    #endif
-    SERIAL_EOL_P(port);
-    #if ENABLED(DISTINCT_E_FACTORS)
-      CONFIG_ECHO_START();
-      for (uint8_t i = 0; i < E_STEPPERS; i++) {
-        SERIAL_ECHOPAIR_P(port, "  M92 T", (int)i);
-        SERIAL_ECHOLNPAIR_P(port, " E", VOLUMETRIC_UNIT(planner.settings.axis_steps_per_mm[E_AXIS + i]));
-      }
-    #endif
+    report_M92(
+      #if NUM_SERIAL > 1
+        port,
+      #endif
+      !forReplay
+    );
 
     CONFIG_ECHO_HEADING("Maximum feedrates (units/s):");
     CONFIG_ECHO_START();