🧑‍💻 Misc. updates for extra axes (#23521)

Marlin/Configuration_adv.h

     #define Z4_SLEW_RATE                 1
   #endif
 
-  #if AXIS_DRIVER_TYPE_I(L6470)
+  #if AXIS_IS_L64XX(I)
     #define I_MICROSTEPS      128
     #define I_OVERCURRENT    2000
     #define I_STALLCURRENT   1500
     #define I_SLEW_RATE         1
   #endif
 
-  #if AXIS_DRIVER_TYPE_J(L6470)
+  #if AXIS_IS_L64XX(J)
     #define J_MICROSTEPS      128
     #define J_OVERCURRENT    2000
     #define J_STALLCURRENT   1500
     #define J_SLEW_RATE         1
   #endif
 
-  #if AXIS_DRIVER_TYPE_K(L6470)
+  #if AXIS_IS_L64XX(K)
     #define K_MICROSTEPS      128
     #define K_OVERCURRENT    2000
     #define K_STALLCURRENT   1500

Marlin/src/HAL/AVR/endstop_interrupts.h

       pciSetup(Z_MIN_PROBE_PIN);
     #endif
   #endif
+
   // If we arrive here without raising an assertion, each pin has either an EXT-interrupt or a PCI.
 }

Marlin/src/core/language.h

     #define STR_I_MIN "w_min"
     #define STR_I_MAX "w_max"
   #else
-    #define STR_I "A"
-    #define STR_I_MIN "a_min"
-    #define STR_I_MAX "a_max"
+    #error "AXIS4_NAME can only be one of 'A', 'B', 'C', 'U', 'V', or 'W'."
   #endif
 #else
   #define STR_I   ""
 #endif
 
 #if HAS_J_AXIS
-  #if AXIS5_NAME == 'A'
-    #define STR_J "A"
-    #define STR_J_MIN "a_min"
-    #define STR_J_MAX "a_max"
-  #elif AXIS5_NAME == 'B'
+  #if AXIS5_NAME == 'B'
     #define STR_J "B"
     #define STR_J_MIN "b_min"
     #define STR_J_MAX "b_max"
     #define STR_J_MIN "w_min"
     #define STR_J_MAX "w_max"
   #else
-    #define STR_J "B"
-    #define STR_J_MIN "b_min"
-    #define STR_J_MAX "b_max"
+    #error "AXIS5_NAME can only be one of 'B', 'C', 'U', 'V', or 'W'."
   #endif
 #else
   #define STR_J   ""
 #endif
 
 #if HAS_K_AXIS
-  #if AXIS6_NAME == 'A'
-    #define STR_K "A"
-    #define STR_K_MIN "a_min"
-    #define STR_K_MAX "a_max"
-  #elif AXIS6_NAME == 'B'
-    #define STR_K "B"
-    #define STR_K_MIN "b_min"
-    #define STR_K_MAX "b_max"
-  #elif AXIS6_NAME == 'C'
+  #if AXIS6_NAME == 'C'
     #define STR_K "C"
     #define STR_K_MIN "c_min"
     #define STR_K_MAX "c_max"
     #define STR_K_MIN "w_min"
     #define STR_K_MAX "w_max"
   #else
-    #define STR_K "C"
-    #define STR_K_MIN "c_min"
-    #define STR_K_MAX "c_max"
+    #error "AXIS6_NAME can only be one of 'C', 'U', 'V', or 'W'."
   #endif
 #else
   #define STR_K   ""

Marlin/src/feature/direct_stepping.cpp

   volatile bool SerialPageManager<Cfg>::fatal_error;
 
   template<typename Cfg>
-  volatile PageState SerialPageManager<Cfg>::page_states[Cfg::NUM_PAGES];
+  volatile PageState SerialPageManager<Cfg>::page_states[Cfg::PAGE_COUNT];
 
   template<typename Cfg>
   volatile bool SerialPageManager<Cfg>::page_states_dirty;
 
   template<typename Cfg>
-  uint8_t SerialPageManager<Cfg>::pages[Cfg::NUM_PAGES][Cfg::PAGE_SIZE];
+  uint8_t SerialPageManager<Cfg>::pages[Cfg::PAGE_COUNT][Cfg::PAGE_SIZE];
 
   template<typename Cfg>
   uint8_t SerialPageManager<Cfg>::checksum;
 
   template <typename Cfg>
   void SerialPageManager<Cfg>::init() {
-    for (int i = 0 ; i < Cfg::NUM_PAGES ; i++)
+    for (int i = 0 ; i < Cfg::PAGE_COUNT ; i++)
       page_states[i] = PageState::FREE;
 
     fatal_error = false;
 
     SERIAL_CHAR(Cfg::CONTROL_CHAR);
     constexpr int state_bits = 2;
-    constexpr int n_bytes = Cfg::NUM_PAGES >> state_bits;
+    constexpr int n_bytes = Cfg::PAGE_COUNT >> state_bits;
     volatile uint8_t bits_b[n_bytes] = { 0 };
 
-    for (page_idx_t i = 0 ; i < Cfg::NUM_PAGES ; i++) {
+    for (page_idx_t i = 0 ; i < Cfg::PAGE_COUNT ; i++) {
       bits_b[i >> state_bits] |= page_states[i] << ((i * state_bits) & 0x7);
     }
 

Marlin/src/feature/direct_stepping.h

     static State state;
     static volatile bool fatal_error;
 
-    static volatile PageState page_states[Cfg::NUM_PAGES];
+    static volatile PageState page_states[Cfg::PAGE_COUNT];
     static volatile bool page_states_dirty;
 
-    static uint8_t pages[Cfg::NUM_PAGES][Cfg::PAGE_SIZE];
+    static uint8_t pages[Cfg::PAGE_COUNT][Cfg::PAGE_SIZE];
     static uint8_t checksum;
     static write_byte_idx_t write_byte_idx;
     static page_idx_t write_page_idx;
   struct config_t {
     static constexpr char CONTROL_CHAR  = '!';
 
-    static constexpr int NUM_PAGES      = num_pages;
-    static constexpr int NUM_AXES       = num_axes;
+    static constexpr int PAGE_COUNT     = num_pages;
+    static constexpr int AXIS_COUNT     = num_axes;
     static constexpr int BITS_SEGMENT   = bits_segment;
     static constexpr int DIRECTIONAL    = dir ? 1 : 0;
     static constexpr int SEGMENTS       = segments;
     static constexpr int NUM_SEGMENTS   = _BV(BITS_SEGMENT);
     static constexpr int SEGMENT_STEPS  = _BV(BITS_SEGMENT - DIRECTIONAL) - 1;
     static constexpr int TOTAL_STEPS    = SEGMENT_STEPS * SEGMENTS;
-    static constexpr int PAGE_SIZE      = (NUM_AXES * BITS_SEGMENT * SEGMENTS) / 8;
+    static constexpr int PAGE_SIZE      = (AXIS_COUNT * BITS_SEGMENT * SEGMENTS) / 8;
 
     typedef typename TypeSelector<(PAGE_SIZE>256), uint16_t, uint8_t>::type write_byte_idx_t;
-    typedef typename TypeSelector<(NUM_PAGES>256), uint16_t, uint8_t>::type page_idx_t;
+    typedef typename TypeSelector<(PAGE_COUNT>256), uint16_t, uint8_t>::type page_idx_t;
   };
 
   template <uint8_t num_pages>

Marlin/src/feature/tmc_util.cpp

         if (monitor_tmc_driver(stepperI, need_update_error_counters, need_debug_reporting))
           step_current_down(stepperI);
       #endif
-
       #if AXIS_IS_TMC(J)
         if (monitor_tmc_driver(stepperJ, need_update_error_counters, need_debug_reporting))
           step_current_down(stepperJ);
       #endif
-
       #if AXIS_IS_TMC(K)
         if (monitor_tmc_driver(stepperK, need_update_error_counters, need_debug_reporting))
           step_current_down(stepperK);

Marlin/src/gcode/calibrate/G28.cpp

   reset_stepper_timeout();
 
   #define HAS_CURRENT_HOME(N) (defined(N##_CURRENT_HOME) && N##_CURRENT_HOME != N##_CURRENT)
-  #if HAS_CURRENT_HOME(X) || HAS_CURRENT_HOME(X2) || HAS_CURRENT_HOME(Y) || HAS_CURRENT_HOME(Y2) || HAS_CURRENT_HOME(I) || HAS_CURRENT_HOME(J) || HAS_CURRENT_HOME(K) || (ENABLED(DELTA) && HAS_CURRENT_HOME(Z))
+  #if HAS_CURRENT_HOME(X) || HAS_CURRENT_HOME(X2) || HAS_CURRENT_HOME(Y) || HAS_CURRENT_HOME(Y2) || (ENABLED(DELTA) && HAS_CURRENT_HOME(Z)) || HAS_CURRENT_HOME(I) || HAS_CURRENT_HOME(J) || HAS_CURRENT_HOME(K)
     #define HAS_HOMING_CURRENT 1
   #endif
 
     #if HAS_CURRENT_HOME(X)
       const int16_t tmc_save_current_X = stepperX.getMilliamps();
       stepperX.rms_current(X_CURRENT_HOME);
-      if (DEBUGGING(LEVELING)) debug_current(F("X"), tmc_save_current_X, X_CURRENT_HOME);
+      if (DEBUGGING(LEVELING)) debug_current(F(STR_X), tmc_save_current_X, X_CURRENT_HOME);
     #endif
     #if HAS_CURRENT_HOME(X2)
       const int16_t tmc_save_current_X2 = stepperX2.getMilliamps();
       stepperX2.rms_current(X2_CURRENT_HOME);
-      if (DEBUGGING(LEVELING)) debug_current(F("X2"), tmc_save_current_X2, X2_CURRENT_HOME);
+      if (DEBUGGING(LEVELING)) debug_current(F(STR_X2), tmc_save_current_X2, X2_CURRENT_HOME);
     #endif
     #if HAS_CURRENT_HOME(Y)
       const int16_t tmc_save_current_Y = stepperY.getMilliamps();
       stepperY.rms_current(Y_CURRENT_HOME);
-      if (DEBUGGING(LEVELING)) debug_current(F("Y"), tmc_save_current_Y, Y_CURRENT_HOME);
+      if (DEBUGGING(LEVELING)) debug_current(F(STR_Y), tmc_save_current_Y, Y_CURRENT_HOME);
     #endif
     #if HAS_CURRENT_HOME(Y2)
       const int16_t tmc_save_current_Y2 = stepperY2.getMilliamps();
       stepperY2.rms_current(Y2_CURRENT_HOME);
-      if (DEBUGGING(LEVELING)) debug_current(F("Y2"), tmc_save_current_Y2, Y2_CURRENT_HOME);
+      if (DEBUGGING(LEVELING)) debug_current(F(STR_Y2), tmc_save_current_Y2, Y2_CURRENT_HOME);
     #endif
     #if HAS_CURRENT_HOME(I)
       const int16_t tmc_save_current_I = stepperI.getMilliamps();
     #if HAS_CURRENT_HOME(Z) && ENABLED(DELTA)
       const int16_t tmc_save_current_Z = stepperZ.getMilliamps();
       stepperZ.rms_current(Z_CURRENT_HOME);
-      if (DEBUGGING(LEVELING)) debug_current(F("Z"), tmc_save_current_Z, Z_CURRENT_HOME);
+      if (DEBUGGING(LEVELING)) debug_current(F(STR_Z), tmc_save_current_Z, Z_CURRENT_HOME);
+    #endif
+    #if HAS_CURRENT_HOME(I)
+      const int16_t tmc_save_current_I = stepperI.getMilliamps();
+      stepperI.rms_current(I_CURRENT_HOME);
+      if (DEBUGGING(LEVELING)) debug_current(F(STR_I), tmc_save_current_I, I_CURRENT_HOME);
+    #endif
+    #if HAS_CURRENT_HOME(J)
+      const int16_t tmc_save_current_J = stepperJ.getMilliamps();
+      stepperJ.rms_current(J_CURRENT_HOME);
+      if (DEBUGGING(LEVELING)) debug_current(F(STR_J), tmc_save_current_J, J_CURRENT_HOME);
+    #endif
+    #if HAS_CURRENT_HOME(K)
+      const int16_t tmc_save_current_K = stepperK.getMilliamps();
+      stepperK.rms_current(K_CURRENT_HOME);
+      if (DEBUGGING(LEVELING)) debug_current(F(STR_K), tmc_save_current_K, K_CURRENT_HOME);
     #endif
   #endif
 
                  homeX = needX || parser.seen_test('X'),
                  homeY = needY || parser.seen_test('Y'),
                  homeZZ = homeZ,
-                 homeI = needI || parser.seen_test(AXIS4_NAME), homeJ = needJ || parser.seen_test(AXIS5_NAME), homeK = needK || parser.seen_test(AXIS6_NAME),
+                 homeI = needI || parser.seen_test(AXIS4_NAME), homeJ = needJ || parser.seen_test(AXIS5_NAME), homeK = needK || parser.seen_test(AXIS6_NAME)
                ),
                home_all = LINEAR_AXIS_GANG(   // Home-all if all or none are flagged
                     homeX == homeX, && homeY == homeX, && homeZ == homeX,

Marlin/src/gcode/calibrate/G425.cpp

 
   park_above_object(m, uncertainty);
 
+  #define _ACASE(N,A,B) case A: dir = -1; case B: axis = N##_AXIS; break
+  #define _PCASE(N) _ACASE(N, N##MINIMUM, N##MAXIMUM)
+
   switch (side) {
     #if AXIS_CAN_CALIBRATE(X)
-      case RIGHT: dir = -1;
-      case LEFT:  axis = X_AXIS; break;
+      _ACASE(X, RIGHT, LEFT);
     #endif
     #if HAS_Y_AXIS && AXIS_CAN_CALIBRATE(Y)
-      case BACK:  dir = -1;
-      case FRONT: axis = Y_AXIS; break;
+      _ACASE(Y, BACK, FRONT);
     #endif
     #if HAS_Z_AXIS && AXIS_CAN_CALIBRATE(Z)
       case TOP: {
       }
     #endif
     #if HAS_I_AXIS && AXIS_CAN_CALIBRATE(I)
-      case IMINIMUM: dir = -1;
-      case IMAXIMUM: axis = I_AXIS; break;
+      _PCASE(I);
     #endif
     #if HAS_J_AXIS && AXIS_CAN_CALIBRATE(J)
-      case JMINIMUM: dir = -1;
-      case JMAXIMUM: axis = J_AXIS; break;
+      _PCASE(J);
     #endif
     #if HAS_K_AXIS && AXIS_CAN_CALIBRATE(K)
-      case KMINIMUM: dir = -1;
-      case KMAXIMUM: axis = K_AXIS; break;
+      _PCASE(K);
     #endif
     default: return;
   }

Marlin/src/gcode/calibrate/M425.cpp

         case Z_AXIS: return AXIS_CAN_CALIBRATE(Z),
         case I_AXIS: return AXIS_CAN_CALIBRATE(I),
         case J_AXIS: return AXIS_CAN_CALIBRATE(J),
-        case K_AXIS: return AXIS_CAN_CALIBRATE(K),
+        case K_AXIS: return AXIS_CAN_CALIBRATE(K)
       );
     }
   };

Marlin/src/gcode/config/M200-M205.cpp

   report_heading_etc(forReplay, F(
     "Advanced (B<min_segment_time_us> S<min_feedrate> T<min_travel_feedrate>"
     TERN_(HAS_JUNCTION_DEVIATION, " J<junc_dev>")
-    TERN_(HAS_CLASSIC_JERK, " X<max_x_jerk> Y<max_y_jerk> Z<max_z_jerk>")
-    TERN_(HAS_CLASSIC_E_JERK, " E<max_e_jerk>")
+    #if HAS_CLASSIC_JERK
+      LINEAR_AXIS_GANG(
+        " X<max_jerk>", " Y<max_jerk>", " Z<max_jerk>",
+        " " STR_I "<max_jerk>", " " STR_J "<max_jerk>", " " STR_K "<max_jerk>"
+      )
+    #endif
+    TERN_(HAS_CLASSIC_E_JERK, " E<max_jerk>")
     ")"
   ));
   SERIAL_ECHOLNPGM_P(

Marlin/src/gcode/config/M217.cpp

  *  W[linear]   0/1 Enable park & Z Raise
  *  X[linear]   Park X (Requires TOOLCHANGE_PARK)
  *  Y[linear]   Park Y (Requires TOOLCHANGE_PARK)
+ *  I[linear]   Park I (Requires TOOLCHANGE_PARK and LINEAR_AXES >= 4)
+ *  J[linear]   Park J (Requires TOOLCHANGE_PARK and LINEAR_AXES >= 5)
+ *  K[linear]   Park K (Requires TOOLCHANGE_PARK and LINEAR_AXES >= 6)
  *  Z[linear]   Z Raise
  *  F[linear]   Fan Speed 0-255
  *  G[linear/s] Fan time
   #if ENABLED(TOOLCHANGE_PARK)
     if (parser.seenval('W')) { toolchange_settings.enable_park = parser.value_linear_units(); }
     if (parser.seenval('X')) { const int16_t v = parser.value_linear_units(); toolchange_settings.change_point.x = constrain(v, X_MIN_POS, X_MAX_POS); }
-    if (parser.seenval('Y')) { const int16_t v = parser.value_linear_units(); toolchange_settings.change_point.y = constrain(v, Y_MIN_POS, Y_MAX_POS); }
+    #if HAS_Y_AXIS
+      if (parser.seenval('Y')) { const int16_t v = parser.value_linear_units(); toolchange_settings.change_point.y = constrain(v, Y_MIN_POS, Y_MAX_POS); }
+    #endif
+    #if HAS_I_AXIS
+      if (parser.seenval('I')) { const int16_t v = parser.value_linear_units(); toolchange_settings.change_point.i = constrain(v, I_MIN_POS, I_MAX_POS); }
+    #endif
+    #if HAS_J_AXIS
+      if (parser.seenval('J')) { const int16_t v = parser.value_linear_units(); toolchange_settings.change_point.j = constrain(v, J_MIN_POS, J_MAX_POS); }
+    #endif
+    #if HAS_K_AXIS
+      if (parser.seenval('K')) { const int16_t v = parser.value_linear_units(); toolchange_settings.change_point.k = constrain(v, K_MIN_POS, K_MAX_POS); }
+    #endif
   #endif
 
-  if (parser.seenval('Z')) { toolchange_settings.z_raise = parser.value_linear_units(); }
+  #if HAS_Z_AXIS
+    if (parser.seenval('Z')) { toolchange_settings.z_raise = parser.value_linear_units(); }
+  #endif
 
   #if ENABLED(TOOLCHANGE_MIGRATION_FEATURE)
     migration.target = 0;       // 0 = disabled
     #endif
 
     #if ENABLED(TOOLCHANGE_PARK)
+    {
       SERIAL_ECHOPGM(" W", LINEAR_UNIT(toolchange_settings.enable_park));
-      SERIAL_ECHOPGM_P(SP_X_STR, LINEAR_UNIT(toolchange_settings.change_point.x));
-      SERIAL_ECHOPGM_P(SP_Y_STR, LINEAR_UNIT(toolchange_settings.change_point.y));
+      SERIAL_ECHOPGM_P(
+            SP_X_STR, LINEAR_UNIT(toolchange_settings.change_point.x)
+        #if HAS_Y_AXIS
+          , SP_Y_STR, LINEAR_UNIT(toolchange_settings.change_point.y)
+        #endif
+        #if HAS_I_AXIS
+          , SP_I_STR, LINEAR_UNIT(toolchange_settings.change_point.i)
+        #endif
+        #if HAS_J_AXIS
+          , SP_J_STR, LINEAR_UNIT(toolchange_settings.change_point.j)
+        #endif
+        #if HAS_K_AXIS
+          , SP_K_STR, LINEAR_UNIT(toolchange_settings.change_point.k)
+        #endif
+      );
+    }
     #endif
 
     #if ENABLED(TOOLCHANGE_FS_PRIME_FIRST_USED)

Marlin/src/gcode/config/M92.cpp

 #include "../../module/planner.h"
 
 /**
- * M92: Set axis steps-per-unit for one or more axes, X, Y, Z, and E.
+ * M92: Set axis steps-per-unit for one or more axes, X, Y, Z, [I, [J, [K]]] and E.
  *      (Follows the same syntax as G92)
  *
  *      With multiple extruders use T to specify which one.

Marlin/src/gcode/feature/digipot/M907-M910.cpp

 #endif
 
 /**
- * M907: Set digital trimpot motor current using axis codes X, Y, Z, E, B, S
+ * M907: Set digital trimpot motor current using axis codes X [Y] [Z] [E]
+ *   B<current> - Special case for 4th (E) axis
+ *   S<current> - Special case to set first 3 axes
  */
 void GcodeSuite::M907() {
   #if HAS_MOTOR_CURRENT_SPI
       if (parser.seenval('E')) stepper.set_digipot_current(2, parser.value_int());
     #endif
 
-  #endif
+  #endif // HAS_MOTOR_CURRENT_PWM
 
   #if HAS_MOTOR_CURRENT_I2C
     // this one uses actual amps in floating point

Marlin/src/gcode/feature/pause/M125.cpp

  *    L<linear> = Override retract Length
  *    X<pos>    = Override park position X
  *    Y<pos>    = Override park position Y
+ *    A<pos>    = Override park position A (requires AXIS*_NAME 'A')
+ *    B<pos>    = Override park position B (requires AXIS*_NAME 'B')
+ *    C<pos>    = Override park position C (requires AXIS*_NAME 'C')
  *    Z<linear> = Override Z raise
  *
  *  With an LCD menu:
 
   xyz_pos_t park_point = NOZZLE_PARK_POINT;
 
-  // Move XY axes to filament change position or given position
-  if (parser.seenval('X')) park_point.x = RAW_X_POSITION(parser.linearval('X'));
-  if (parser.seenval('Y')) park_point.y = RAW_X_POSITION(parser.linearval('Y'));
+  // Move to filament change position or given position
+  LINEAR_AXIS_CODE(
+    if (parser.seenval('X')) park_point.x = RAW_X_POSITION(parser.linearval('X')),
+    if (parser.seenval('Y')) park_point.y = RAW_Y_POSITION(parser.linearval('Y')),
+    NOOP,
+    if (parser.seenval(AXIS4_NAME)) park_point.i = RAW_I_POSITION(parser.linearval(AXIS4_NAME)),
+    if (parser.seenval(AXIS5_NAME)) park_point.j = RAW_J_POSITION(parser.linearval(AXIS5_NAME)),
+    if (parser.seenval(AXIS6_NAME)) park_point.k = RAW_K_POSITION(parser.linearval(AXIS6_NAME))
+  );
 
   // Lift Z axis
   if (parser.seenval('Z')) park_point.z = parser.linearval('Z');

Marlin/src/gcode/feature/pause/M600.cpp

   if (standardM600)
     ui.pause_show_message(PAUSE_MESSAGE_CHANGING, PAUSE_MODE_PAUSE_PRINT, target_extruder);
 
-  #if ENABLED(HOME_BEFORE_FILAMENT_CHANGE)
-    // If needed, home before parking for filament change
-    home_if_needed(true);
-  #endif
+  // If needed, home before parking for filament change
+  TERN_(HOME_BEFORE_FILAMENT_CHANGE, home_if_needed(true));
 
   #if HAS_MULTI_EXTRUDER
     // Change toolhead if specified
 
   xyz_pos_t park_point NOZZLE_PARK_POINT;
 
-  // Lift Z axis
+  // Lift Z axis first
   if (parser.seenval('Z')) park_point.z = parser.linearval('Z');
 
   // Move XY axes to filament change position or given position
-  if (parser.seenval('X')) park_point.x = parser.linearval('X');
-  if (parser.seenval('Y')) park_point.y = parser.linearval('Y');
+  LINEAR_AXIS_CODE(
+    if (parser.seenval('X')) park_point.x = parser.linearval('X'),
+    if (parser.seenval('Y')) park_point.y = parser.linearval('Y'),
+    NOOP,
+    if (parser.seenval(AXIS4_NAME)) park_point.i = parser.linearval(AXIS4_NAME);
+    if (parser.seenval(AXIS5_NAME)) park_point.j = parser.linearval(AXIS5_NAME);
+    if (parser.seenval(AXIS6_NAME)) park_point.k = parser.linearval(AXIS6_NAME);
+  );
 
   #if HAS_HOTEND_OFFSET && NONE(DUAL_X_CARRIAGE, DELTA)
     park_point += hotend_offset[active_extruder];

Marlin/src/gcode/feature/trinamic/M906.cpp

  *   X[current]  - Set mA current for X driver(s)
  *   Y[current]  - Set mA current for Y driver(s)
  *   Z[current]  - Set mA current for Z driver(s)
+ *   A[current]  - Set mA current for A driver(s) (Requires AXIS*_NAME 'A')
+ *   B[current]  - Set mA current for B driver(s) (Requires AXIS*_NAME 'B')
+ *   C[current]  - Set mA current for C driver(s) (Requires AXIS*_NAME 'C')
  *   E[current]  - Set mA current for E driver(s)
  *
  *   I[index]    - Axis sub-index (Omit or 0 for X, Y, Z; 1 for X2, Y2, Z2; 2 for Z3; 3 for Z4.)

Marlin/src/gcode/geometry/G92.cpp

 #endif
 
 /**
- * G92: Set the Current Position to the given X Y Z E values.
+ * G92: Set the Current Position to the given X [Y [Z [A [B [C [E]]]]]] values.
  *
  * Behind the scenes the G92 command may modify the Current Position
  * or the Position Shift depending on settings and sub-commands.
  * Since E has no Workspace Offset, it is always set directly.
  *
  * Without Workspace Offsets (e.g., with NO_WORKSPACE_OFFSETS):
- *   G92   : Set NATIVE Current Position to the given X Y Z E.
+ *   G92   : Set NATIVE Current Position to the given X [Y [Z [A [B [C [E]]]]]].
  *
  * Using Workspace Offsets (default Marlin behavior):
- *   G92   : Modify Workspace Offsets so the reported position shows the given X Y Z E.
+ *   G92   : Modify Workspace Offsets so the reported position shows the given X [Y [Z [A [B [C [E]]]]]].
  *   G92.1 : Zero XYZ Workspace Offsets (so the reported position = the native position).
  *
  * With POWER_LOSS_RECOVERY:
- *   G92.9 : Set NATIVE Current Position to the given X Y Z E.
+ *   G92.9 : Set NATIVE Current Position to the given X [Y [Z [A [B [C [E]]]]]].
  */
 void GcodeSuite::G92() {
 

Marlin/src/inc/Conditionals_post.h

 #define TMC_UART_IS(A,N) (defined(A##_HARDWARE_SERIAL) && (CAT(HW_,A##_HARDWARE_SERIAL) == HW_Serial##N || CAT(HW_,A##_HARDWARE_SERIAL) == HW_MSerial##N))
 #define ANY_SERIAL_IS(N) (  CONF_SERIAL_IS(N) \
                          || TMC_UART_IS(X,  N) || TMC_UART_IS(Y , N) || TMC_UART_IS(Z , N) \
+                         || TMC_UART_IS(I,  N) || TMC_UART_IS(J , N) || TMC_UART_IS(K , N) \
                          || TMC_UART_IS(X2, N) || TMC_UART_IS(Y2, N) || TMC_UART_IS(Z2, N) || TMC_UART_IS(Z3, N) || TMC_UART_IS(Z4, N) \
                          || TMC_UART_IS(E0, N) || TMC_UART_IS(E1, N) || TMC_UART_IS(E2, N) || TMC_UART_IS(E3, N) || TMC_UART_IS(E4, N) )
 

Marlin/src/inc/SanityCheck.h

   #error "Enable only one of ENDSTOPPULLUP_Y_MAX or ENDSTOPPULLDOWN_Y_MAX."
 #elif BOTH(ENDSTOPPULLUP_ZMAX, ENDSTOPPULLDOWN_ZMAX)
   #error "Enable only one of ENDSTOPPULLUP_Z_MAX or ENDSTOPPULLDOWN_Z_MAX."
+#elif BOTH(ENDSTOPPULLUP_IMAX, ENDSTOPPULLDOWN_IMAX)
+  #error "Enable only one of ENDSTOPPULLUP_I_MAX or ENDSTOPPULLDOWN_I_MAX."
+#elif BOTH(ENDSTOPPULLUP_JMAX, ENDSTOPPULLDOWN_JMAX)
+  #error "Enable only one of ENDSTOPPULLUP_J_MAX or ENDSTOPPULLDOWN_J_MAX."
+#elif BOTH(ENDSTOPPULLUP_KMAX, ENDSTOPPULLDOWN_KMAX)
+  #error "Enable only one of ENDSTOPPULLUP_K_MAX or ENDSTOPPULLDOWN_K_MAX."
 #elif BOTH(ENDSTOPPULLUP_XMIN, ENDSTOPPULLDOWN_XMIN)
   #error "Enable only one of ENDSTOPPULLUP_X_MIN or ENDSTOPPULLDOWN_X_MIN."
 #elif BOTH(ENDSTOPPULLUP_YMIN, ENDSTOPPULLDOWN_YMIN)
  * Allow only extra axis codes that do not conflict with G-code parameter names
  */
 #if HAS_I_AXIS
-  #if AXIS4_NAME != 'A' && AXIS4_NAME != 'B' && AXIS4_NAME != 'C' && AXIS4_NAME != 'U' && AXIS4_NAME != 'V' && AXIS4_NAME != 'W'
-    #error "AXIS4_NAME can only be one of 'A', 'B', 'C', 'U', 'V', or 'W'."
-  #elif !defined(I_MIN_POS) || !defined(I_MAX_POS)
+  #if !defined(I_MIN_POS) || !defined(I_MAX_POS)
     #error "I_MIN_POS and I_MAX_POS are required with LINEAR_AXES >= 4."
   #elif !defined(I_HOME_DIR)
     #error "I_HOME_DIR is required with LINEAR_AXES >= 4."
 #if HAS_J_AXIS
   #if AXIS5_NAME == AXIS4_NAME
     #error "AXIS5_NAME must be unique."
-  #elif AXIS5_NAME != 'A' && AXIS5_NAME != 'B' && AXIS5_NAME != 'C' && AXIS5_NAME != 'U' && AXIS5_NAME != 'V' && AXIS5_NAME != 'W'
-    #error "AXIS5_NAME can only be one of 'A', 'B', 'C', 'U', 'V', or 'W'."
   #elif !defined(J_MIN_POS) || !defined(J_MAX_POS)
     #error "J_MIN_POS and J_MAX_POS are required with LINEAR_AXES >= 5."
   #elif !defined(J_HOME_DIR)
 #if HAS_K_AXIS
   #if AXIS6_NAME == AXIS5_NAME || AXIS6_NAME == AXIS4_NAME
     #error "AXIS6_NAME must be unique."
-  #elif AXIS6_NAME != 'A' && AXIS6_NAME != 'B' && AXIS6_NAME != 'C' && AXIS6_NAME != 'U' && AXIS6_NAME != 'V' && AXIS6_NAME != 'W'
-    #error "AXIS6_NAME can only be one of 'A', 'B', 'C', 'U', 'V', or 'W'."
   #elif !defined(K_MIN_POS) || !defined(K_MAX_POS)
     #error "K_MIN_POS and K_MAX_POS are required with LINEAR_AXES >= 6."
   #elif !defined(K_HOME_DIR)
  * L64XX requirement
  */
 #if HAS_L64XX && HAS_I_AXIS
-  #error "L64XX requires LINEAR_AXES 3. Homing with L64XX is not yet implemented for LINEAR_AXES > 3."
+  #error "L64XX requires LINEAR_AXES <= 3. Homing with L64XX is not yet implemented for LINEAR_AXES > 3."
 #endif
 
 /**
 #if _BAD_DRIVER(Z)
   #error "Z_DRIVER_TYPE is not recognized."
 #endif
-#if HAS_I_AXIS
-  #if _BAD_DRIVER(I)
-    #error "I_DRIVER_TYPE is not recognized."
-  #endif
+#if _BAD_DRIVER(I)
+  #error "I_DRIVER_TYPE is not recognized."
 #endif
-#if HAS_J_AXIS
-  #if _BAD_DRIVER(J)
-    #error "J_DRIVER_TYPE is not recognized."
-  #endif
+#if _BAD_DRIVER(J)
+  #error "J_DRIVER_TYPE is not recognized."
 #endif
-#if HAS_K_AXIS
-  #if _BAD_DRIVER(K)
-    #error "K_DRIVER_TYPE is not recognized."
-  #endif
+#if _BAD_DRIVER(K)
+  #error "K_DRIVER_TYPE is not recognized."
 #endif
-
 #if _BAD_DRIVER(X2)
   #error "X2_DRIVER_TYPE is not recognized."
 #endif

Marlin/src/module/endstops.cpp

   #if HAS_J_MAX
     ES_REPORT(J_MAX);
   #endif
-    #if HAS_K_MIN
+  #if HAS_K_MIN
     ES_REPORT(K_MIN);
   #endif
   #if HAS_K_MAX

Marlin/src/module/motion.cpp

 }
 
 /**
- * Plan a move to (X, Y, Z, [I, [J, [K]]]) and set the current_position
- * Plan a move to (X, Y, Z) with separation of Z from other components.
+ * Plan a move to (X, Y, Z, [I, [J, [K...]]]) and set the current_position
+ * Plan a move to (X, Y, Z, [I, [J, [K...]]]) with separation of Z from other components.
  *
  * - If Z is moving up, the Z move is done before XY, etc.
  * - If Z is moving down, the Z move is done after XY, etc.
   #if HAS_Z_AXIS
     const feedRate_t z_feedrate = fr_mm_s ?: homing_feedrate(Z_AXIS);
   #endif
+  #if HAS_I_AXIS
+    const feedRate_t i_feedrate = fr_mm_s ?: homing_feedrate(I_AXIS);
+  #endif
+  #if HAS_J_AXIS
+    const feedRate_t j_feedrate = fr_mm_s ?: homing_feedrate(J_AXIS);
+  #endif
+  #if HAS_K_AXIS
+    const feedRate_t k_feedrate = fr_mm_s ?: homing_feedrate(K_AXIS);
+  #endif
 
   #if IS_KINEMATIC
     if (!position_is_reachable(x, y)) return;
 
     // when in the danger zone
     if (current_position.z > delta_clip_start_height) {
-      if (z > delta_clip_start_height) {                     // staying in the danger zone
-        destination.set(x, y, z);                          // move directly (uninterpolated)
+      if (z > delta_clip_start_height) {                      // staying in the danger zone
+        destination.set(x, y, z);                             // move directly (uninterpolated)
         prepare_internal_fast_move_to_destination();          // set current_position from destination
         if (DEBUGGING(LEVELING)) DEBUG_POS("danger zone move", current_position);
         return;
       if (DEBUGGING(LEVELING)) DEBUG_POS("zone border move", current_position);
     }
 
-    if (z > current_position.z) {                            // raising?
+    if (z > current_position.z) {                             // raising?
       destination.z = z;
       prepare_internal_fast_move_to_destination(z_feedrate);  // set current_position from destination
       if (DEBUGGING(LEVELING)) DEBUG_POS("z raise move", current_position);
     prepare_internal_move_to_destination();                   // set current_position from destination
     if (DEBUGGING(LEVELING)) DEBUG_POS("xy move", current_position);
 
-    if (z < current_position.z) {                            // lowering?
+    if (z < current_position.z) {                             // lowering?
       destination.z = z;
       prepare_internal_fast_move_to_destination(z_feedrate);  // set current_position from destination
       if (DEBUGGING(LEVELING)) DEBUG_POS("z lower move", current_position);
   #elif IS_SCARA
 
     // If Z needs to raise, do it before moving XY
-    if (destination.z < z) {
-      destination.z = z;
-      prepare_internal_fast_move_to_destination(z_feedrate);
-    }
+    if (destination.z < z) { destination.z = z; prepare_internal_fast_move_to_destination(z_feedrate); }
 
-    destination.set(x, y);
-    prepare_internal_fast_move_to_destination(xy_feedrate);
+    destination.set(x, y); prepare_internal_fast_move_to_destination(xy_feedrate);
 
     // If Z needs to lower, do it after moving XY
-    if (destination.z > z) {
-      destination.z = z;
-      prepare_internal_fast_move_to_destination(z_feedrate);
-    }
+    if (destination.z > z) { destination.z = z; prepare_internal_fast_move_to_destination(z_feedrate); }
 
   #else
 
-    #if HAS_Z_AXIS
-      // If Z needs to raise, do it before moving XY
-      if (current_position.z < z) {
-        current_position.z = z;
-        line_to_current_position(z_feedrate);
-      }
+    #if HAS_Z_AXIS  // If Z needs to raise, do it before moving XY
+      if (current_position.z < z) { current_position.z = z; line_to_current_position(z_feedrate); }
     #endif
 
-    current_position.set(x, y);
-    line_to_current_position(xy_feedrate);
+    current_position.set(x, y); line_to_current_position(xy_feedrate);
 
-    #if HAS_Z_AXIS
-      // If Z needs to lower, do it after moving XY
-      if (current_position.z > z) {
-        current_position.z = z;
-        line_to_current_position(z_feedrate);
-      }
+    #if HAS_I_AXIS
+      current_position.i = i; line_to_current_position(i_feedrate);
+    #endif
+    #if HAS_J_AXIS
+      current_position.j = j; line_to_current_position(j_feedrate);
+    #endif
+    #if HAS_K_AXIS
+      current_position.k = k; line_to_current_position(k_feedrate);
+    #endif
+    #if HAS_Z_AXIS  // If Z needs to lower, do it after moving XY...
+      if (current_position.z > z) { current_position.z = z; line_to_current_position(z_feedrate); }
     #endif
 
   #endif
             #endif
             break;
         #endif
+        #if I_SENSORLESS
+          case I_AXIS: stealth_states.i = tmc_enable_stallguard(stepperI); break;
+        #endif
+        #if J_SENSORLESS
+          case J_AXIS: stealth_states.j = tmc_enable_stallguard(stepperJ); break;
+        #endif
+        #if K_SENSORLESS
+          case K_AXIS: stealth_states.k = tmc_enable_stallguard(stepperK); break;
+        #endif
       }
 
       #if ENABLED(SPI_ENDSTOPS)
             #endif
             break;
         #endif
+        #if I_SENSORLESS
+          case I_AXIS: tmc_disable_stallguard(stepperI, enable_stealth.i); break;
+        #endif
+        #if J_SENSORLESS
+          case J_AXIS: tmc_disable_stallguard(stepperJ, enable_stealth.j); break;
+        #endif
+        #if K_SENSORLESS
+          case K_AXIS: tmc_disable_stallguard(stepperK, enable_stealth.k); break;
+        #endif
       }
 
       #if ENABLED(SPI_ENDSTOPS)
         switch (axis) {
           default:
           case X_AXIS: es = X_ENDSTOP; break;
-          case Y_AXIS: es = Y_ENDSTOP; break;
-          case Z_AXIS: es = Z_ENDSTOP; break;
+          #if HAS_Y_AXIS
+            case Y_AXIS: es = Y_ENDSTOP; break;
+          #endif
+          #if HAS_Z_AXIS
+            case Z_AXIS: es = Z_ENDSTOP; break;
+          #endif
           #if HAS_I_AXIS
             case I_AXIS: es = I_ENDSTOP; break;
           #endif

Marlin/src/module/planner.cpp

       steps_dist_mm.b      = (db + dc) * mm_per_step[B_AXIS];
       steps_dist_mm.c      = CORESIGN(db - dc) * mm_per_step[C_AXIS];
     #endif
-    #if HAS_I_AXIS
-      steps_dist_mm.i = di * mm_per_step[I_AXIS];
-    #endif
-    #if HAS_J_AXIS
-      steps_dist_mm.j = dj * mm_per_step[J_AXIS];
-    #endif
-    #if HAS_K_AXIS
-      steps_dist_mm.k = dk * mm_per_step[K_AXIS];
-    #endif
+    TERN_(HAS_I_AXIS, steps_dist_mm.i = di * mm_per_step[I_AXIS]);
+    TERN_(HAS_J_AXIS, steps_dist_mm.j = dj * mm_per_step[J_AXIS]);
+    TERN_(HAS_K_AXIS, steps_dist_mm.k = dk * mm_per_step[K_AXIS]);
   #elif ENABLED(MARKFORGED_XY)
     steps_dist_mm.a      = (da - db) * mm_per_step[A_AXIS];
     steps_dist_mm.b      = db * mm_per_step[B_AXIS];
     );
   #endif
   #if ANY(CORE_IS_XY, MARKFORGED_XY, MARKFORGED_YX)
-    #if HAS_I_AXIS
-      if (block->steps.i) stepper.enable_axis(I_AXIS);
-    #endif
-    #if HAS_J_AXIS
-      if (block->steps.j) stepper.enable_axis(J_AXIS);
-    #endif
-    #if HAS_K_AXIS
-      if (block->steps.k) stepper.enable_axis(K_AXIS);
-    #endif
+    TERN_(HAS_I_AXIS, if (block->steps.i) stepper.enable_axis(I_AXIS));
+    TERN_(HAS_J_AXIS, if (block->steps.j) stepper.enable_axis(J_AXIS));
+    TERN_(HAS_K_AXIS, if (block->steps.k) stepper.enable_axis(K_AXIS));
   #endif
 
   // Enable extruder(s)
 
   // Slow down when the buffer starts to empty, rather than wait at the corner for a buffer refill
   #if EITHER(SLOWDOWN, HAS_WIRED_LCD) || defined(XY_FREQUENCY_LIMIT)
-    // Segment time im micro seconds
+    // Segment time in microseconds
     int32_t segment_time_us = LROUND(1000000.0f / inverse_secs);
   #endif
 
     accel = CEIL((esteps ? settings.acceleration : settings.travel_acceleration) * steps_per_mm);
 
     #if ENABLED(LIN_ADVANCE)
-
+      // Linear advance is currently not ready for HAS_I_AXIS
       #define MAX_E_JERK(N) TERN(HAS_LINEAR_E_JERK, max_e_jerk[E_INDEX_N(N)], max_jerk.e)
 
       /**
       SERIAL_ECHOPGM_P(SP_Y_LBL, abce.b);
     #endif
     SERIAL_ECHOPGM(" (", position.y, "->", target.y);
-    #if LINEAR_AXES >= ABC
+    #if HAS_Z_AXIS
       #if ENABLED(DELTA)
         SERIAL_ECHOPGM(") C:", abce.c);
       #else

Marlin/src/module/probe.cpp

   #endif
 
   // On delta keep Z below clip height or do_blocking_move_to will abort
-  xyz_pos_t npos = { rx, ry, TERN(DELTA, _MIN(delta_clip_start_height, current_position.z), current_position.z) };
+  xyz_pos_t npos = LINEAR_AXIS_ARRAY(
+    rx, ry, TERN(DELTA, _MIN(delta_clip_start_height, current_position.z), current_position.z),
+    current_position.i, current_position.j, current_position.k
+  );
   if (!can_reach(npos, probe_relative)) {
     if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("Position Not Reachable");
     return NAN;

Marlin/src/module/stepper.cpp

     }
   }
 
-  bool Stepper::disable_extruder(E_TERN_(const uint8_t eindex)) {
+  bool Stepper::disable_extruder(E_TERN_(const uint8_t eindex/*=0*/)) {
     IF_DISABLED(HAS_MULTI_EXTRUDER, constexpr uint8_t eindex = 0);
     mark_axis_disabled(E_AXIS E_OPTARG(eindex));
     const bool can_disable = can_axis_disable(E_AXIS E_OPTARG(eindex));
     const bool is_page = IS_PAGE(current_block);
 
     #if ENABLED(DIRECT_STEPPING)
-      // TODO (DerAndere): Add support for HAS_I_AXIS
+      // Direct stepping is currently not ready for HAS_I_AXIS
       if (is_page) {
 
         #if STEPPER_PAGE_FORMAT == SP_4x4D_128
     // If current block is finished, reset pointer and finalize state
     if (step_events_completed >= step_event_count) {
       #if ENABLED(DIRECT_STEPPING)
-        // TODO (DerAndere): Add support for HAS_I_AXIS
+        // Direct stepping is currently not ready for HAS_I_AXIS
         #if STEPPER_PAGE_FORMAT == SP_4x4D_128
           #define PAGE_SEGMENT_UPDATE_POS(AXIS) \
             count_position[_AXIS(AXIS)] += page_step_state.bd[_AXIS(AXIS)] - 128 * 7;
 
   void Stepper::microstep_init() {
     #if HAS_X_MS_PINS
-      SET_OUTPUT(X_MS1_PIN);
-      SET_OUTPUT(X_MS2_PIN);
+      SET_OUTPUT(X_MS1_PIN); SET_OUTPUT(X_MS2_PIN);
       #if PIN_EXISTS(X_MS3)
         SET_OUTPUT(X_MS3_PIN);
       #endif
     #endif
     #if HAS_X2_MS_PINS
-      SET_OUTPUT(X2_MS1_PIN);
-      SET_OUTPUT(X2_MS2_PIN);
+      SET_OUTPUT(X2_MS1_PIN); SET_OUTPUT(X2_MS2_PIN);
       #if PIN_EXISTS(X2_MS3)
         SET_OUTPUT(X2_MS3_PIN);
       #endif
     #endif
     #if HAS_Y_MS_PINS
-      SET_OUTPUT(Y_MS1_PIN);
-      SET_OUTPUT(Y_MS2_PIN);
+      SET_OUTPUT(Y_MS1_PIN); SET_OUTPUT(Y_MS2_PIN);
       #if PIN_EXISTS(Y_MS3)
         SET_OUTPUT(Y_MS3_PIN);
       #endif
     #endif
     #if HAS_Y2_MS_PINS
-      SET_OUTPUT(Y2_MS1_PIN);
-      SET_OUTPUT(Y2_MS2_PIN);
+      SET_OUTPUT(Y2_MS1_PIN); SET_OUTPUT(Y2_MS2_PIN);
       #if PIN_EXISTS(Y2_MS3)
         SET_OUTPUT(Y2_MS3_PIN);
       #endif
     #endif
     #if HAS_Z_MS_PINS
-      SET_OUTPUT(Z_MS1_PIN);
-      SET_OUTPUT(Z_MS2_PIN);
+      SET_OUTPUT(Z_MS1_PIN); SET_OUTPUT(Z_MS2_PIN);
       #if PIN_EXISTS(Z_MS3)
         SET_OUTPUT(Z_MS3_PIN);
       #endif
     #endif
     #if HAS_Z2_MS_PINS
-      SET_OUTPUT(Z2_MS1_PIN);
-      SET_OUTPUT(Z2_MS2_PIN);
+      SET_OUTPUT(Z2_MS1_PIN); SET_OUTPUT(Z2_MS2_PIN);
       #if PIN_EXISTS(Z2_MS3)
         SET_OUTPUT(Z2_MS3_PIN);
       #endif
     #endif
     #if HAS_Z3_MS_PINS
-      SET_OUTPUT(Z3_MS1_PIN);
-      SET_OUTPUT(Z3_MS2_PIN);
+      SET_OUTPUT(Z3_MS1_PIN); SET_OUTPUT(Z3_MS2_PIN);
       #if PIN_EXISTS(Z3_MS3)
         SET_OUTPUT(Z3_MS3_PIN);
       #endif
     #endif
     #if HAS_Z4_MS_PINS
-      SET_OUTPUT(Z4_MS1_PIN);
-      SET_OUTPUT(Z4_MS2_PIN);
+      SET_OUTPUT(Z4_MS1_PIN); SET_OUTPUT(Z4_MS2_PIN);
       #if PIN_EXISTS(Z4_MS3)
         SET_OUTPUT(Z4_MS3_PIN);
       #endif
     #endif
+    #if HAS_I_MS_PINS
+      SET_OUTPUT(I_MS1_PIN); SET_OUTPUT(I_MS2_PIN);
+      #if PIN_EXISTS(I_MS3)
+        SET_OUTPUT(I_MS3_PIN);
+      #endif
+    #endif
+    #if HAS_J_MS_PINS
+      SET_OUTPUT(J_MS1_PIN); SET_OUTPUT(J_MS2_PIN);
+      #if PIN_EXISTS(J_MS3)
+        SET_OUTPUT(J_MS3_PIN);
+      #endif
+    #endif
+    #if HAS_K_MS_PINS
+      SET_OUTPUT(K_MS1_PIN); SET_OUTPUT(K_MS2_PIN);
+      #if PIN_EXISTS(K_MS3)
+        SET_OUTPUT(K_MS3_PIN);
+      #endif
+    #endif
     #if HAS_E0_MS_PINS
-      SET_OUTPUT(E0_MS1_PIN);
-      SET_OUTPUT(E0_MS2_PIN);
+      SET_OUTPUT(E0_MS1_PIN); SET_OUTPUT(E0_MS2_PIN);
       #if PIN_EXISTS(E0_MS3)
         SET_OUTPUT(E0_MS3_PIN);
       #endif
     #endif
     #if HAS_E1_MS_PINS
-      SET_OUTPUT(E1_MS1_PIN);
-      SET_OUTPUT(E1_MS2_PIN);
+      SET_OUTPUT(E1_MS1_PIN); SET_OUTPUT(E1_MS2_PIN);
       #if PIN_EXISTS(E1_MS3)
         SET_OUTPUT(E1_MS3_PIN);
       #endif
     #endif
     #if HAS_E2_MS_PINS
-      SET_OUTPUT(E2_MS1_PIN);
-      SET_OUTPUT(E2_MS2_PIN);
+      SET_OUTPUT(E2_MS1_PIN); SET_OUTPUT(E2_MS2_PIN);
       #if PIN_EXISTS(E2_MS3)
         SET_OUTPUT(E2_MS3_PIN);
       #endif
     #endif
     #if HAS_E3_MS_PINS
-      SET_OUTPUT(E3_MS1_PIN);
-      SET_OUTPUT(E3_MS2_PIN);
+      SET_OUTPUT(E3_MS1_PIN); SET_OUTPUT(E3_MS2_PIN);
       #if PIN_EXISTS(E3_MS3)
         SET_OUTPUT(E3_MS3_PIN);
       #endif
     #endif
     #if HAS_E4_MS_PINS
-      SET_OUTPUT(E4_MS1_PIN);
-      SET_OUTPUT(E4_MS2_PIN);
+      SET_OUTPUT(E4_MS1_PIN); SET_OUTPUT(E4_MS2_PIN);
       #if PIN_EXISTS(E4_MS3)
         SET_OUTPUT(E4_MS3_PIN);
       #endif
     #endif
     #if HAS_E5_MS_PINS
-      SET_OUTPUT(E5_MS1_PIN);
-      SET_OUTPUT(E5_MS2_PIN);
+      SET_OUTPUT(E5_MS1_PIN); SET_OUTPUT(E5_MS2_PIN);
       #if PIN_EXISTS(E5_MS3)
         SET_OUTPUT(E5_MS3_PIN);
       #endif
     #endif
     #if HAS_E6_MS_PINS
-      SET_OUTPUT(E6_MS1_PIN);
-      SET_OUTPUT(E6_MS2_PIN);
+      SET_OUTPUT(E6_MS1_PIN); SET_OUTPUT(E6_MS2_PIN);
       #if PIN_EXISTS(E6_MS3)
         SET_OUTPUT(E6_MS3_PIN);
       #endif
     #endif
     #if HAS_E7_MS_PINS
-      SET_OUTPUT(E7_MS1_PIN);
-      SET_OUTPUT(E7_MS2_PIN);
+      SET_OUTPUT(E7_MS1_PIN); SET_OUTPUT(E7_MS2_PIN);
       #if PIN_EXISTS(E7_MS3)
         SET_OUTPUT(E7_MS3_PIN);
       #endif
       #if HAS_E7_MS_PINS
         case 10: WRITE(E7_MS1_PIN, ms1); break;
       #endif
-      #if HAS_I_MICROSTEPS
+      #if HAS_I_MS_PINS
         case 11: WRITE(I_MS1_PIN, ms1); break
       #endif
-      #if HAS_J_MICROSTEPS
+      #if HAS_J_MS_PINS
         case 12: WRITE(J_MS1_PIN, ms1); break
       #endif
-      #if HAS_K_MICROSTEPS
+      #if HAS_K_MS_PINS
         case 13: WRITE(K_MS1_PIN, ms1); break
       #endif
     }
       #if HAS_E7_MS_PINS
         case 10: WRITE(E7_MS2_PIN, ms2); break;
       #endif
-      #if HAS_I_M_PINS
+      #if HAS_I_MS_PINS
         case 11: WRITE(I_MS2_PIN, ms2); break
       #endif
-      #if HAS_J_M_PINS
+      #if HAS_J_MS_PINS
         case 12: WRITE(J_MS2_PIN, ms2); break
       #endif
-      #if HAS_K_M_PINS
+      #if HAS_K_MS_PINS
         case 13: WRITE(K_MS2_PIN, ms2); break
       #endif
     }

Marlin/src/module/stepper.h

         #ifndef MOTOR_CURRENT_PWM_FREQUENCY
           #define MOTOR_CURRENT_PWM_FREQUENCY 31400
         #endif
-
         #define MOTOR_CURRENT_COUNT LINEAR_AXES
       #elif HAS_MOTOR_CURRENT_SPI
         static constexpr uint32_t digipot_count[] = DIGIPOT_MOTOR_CURRENT;

Marlin/src/pins/pinsDebug_list.h

 #if PIN_EXISTS(Z4_SERIAL_RX)
   REPORT_NAME_DIGITAL(__LINE__, Z4_SERIAL_RX_PIN)
 #endif
+#if PIN_EXISTS(I_SERIAL_TX)
+  REPORT_NAME_DIGITAL(__LINE__, I_SERIAL_TX_PIN)
+#endif
+#if PIN_EXISTS(I_SERIAL_RX)
+  REPORT_NAME_DIGITAL(__LINE__, I_SERIAL_RX_PIN)
+#endif
+#if PIN_EXISTS(J_SERIAL_TX)
+  REPORT_NAME_DIGITAL(__LINE__, J_SERIAL_TX_PIN)
+#endif
+#if PIN_EXISTS(J_SERIAL_RX)
+  REPORT_NAME_DIGITAL(__LINE__, J_SERIAL_RX_PIN)
+#endif
+#if PIN_EXISTS(K_SERIAL_TX)
+  REPORT_NAME_DIGITAL(__LINE__, K_SERIAL_TX_PIN)
+#endif
+#if PIN_EXISTS(K_SERIAL_RX)
+  REPORT_NAME_DIGITAL(__LINE__, K_SERIAL_RX_PIN)
+#endif
 #if PIN_EXISTS(E0_DIAG)
   REPORT_NAME_DIGITAL(__LINE__, E0_DIAG_PIN)
 #endif

Marlin/src/pins/pins_postprocess.h

   #undef K_MAX_PIN
 #endif
 
+// Filament Sensor first pin alias
 #if HAS_FILAMENT_SENSOR
   #define FIL_RUNOUT1_PIN FIL_RUNOUT_PIN  // Filament Sensor first pin alias
 #else
   #define X2_E_INDEX E_STEPPERS
 #endif
 
-// The X2 axis, if any, should be the next open extruder port
 #if HAS_X2_STEPPER && !defined(X2_DIAG_PIN) && !defined(X2_STEP_PIN) && !PIN_EXISTS(X2_CS_PIN)
   #define Y2_E_INDEX INCREMENT(X2_E_INDEX)
 #else
   #define Y2_E_INDEX X2_E_INDEX
 #endif
+
+// The X2 axis, if any, should be the next open extruder port
 #if HAS_X2_STEPPER
   #ifndef X2_STEP_PIN
     #define X2_STEP_PIN   _EPIN(X2_E_INDEX, STEP)
   #define X2_MS3_PIN -1
 #endif
 
-// The Y2 axis, if any, should be the next open extruder port
 #if ENABLED(Y_DUAL_STEPPER_DRIVERS) && !defined(Y2_DIAG_PIN) && !defined(Y2_STEP_PIN) && !PIN_EXISTS(Y2_CS_PIN)
   #define Z2_E_INDEX INCREMENT(Y2_E_INDEX)
 #else
   #define Z2_E_INDEX Y2_E_INDEX
 #endif
+
+// The Y2 axis, if any, should be the next open extruder port
 #if ENABLED(Y_DUAL_STEPPER_DRIVERS)
   #ifndef Y2_STEP_PIN
     #define Y2_STEP_PIN   _EPIN(Y2_E_INDEX, STEP)
   #define Y2_MS3_PIN -1
 #endif
 
-// The Z2 axis, if any, should be the next open extruder port
 #if NUM_Z_STEPPER_DRIVERS >= 2 && !defined(Z2_DIAG_PIN) && !defined(Z2_STEP_PIN) && !PIN_EXISTS(Z2_CS_PIN)
   #define Z3_E_INDEX INCREMENT(Z2_E_INDEX)
 #else
   #define Z3_E_INDEX Z2_E_INDEX
 #endif
+
+// The Z2 axis, if any, should be the next open extruder port
 #if NUM_Z_STEPPER_DRIVERS >= 2
   #ifndef Z2_STEP_PIN
     #define Z2_STEP_PIN   _EPIN(Z2_E_INDEX, STEP)
   #define Z2_MS3_PIN -1
 #endif
 
-// The Z3 axis, if any, should be the next open extruder port
 #if NUM_Z_STEPPER_DRIVERS >= 3 && !defined(Z3_DIAG_PIN) && !defined(Z3_STEP_PIN) && !PIN_EXISTS(Z3_CS_PIN)
   #define Z4_E_INDEX INCREMENT(Z3_E_INDEX)
 #else
   #define Z4_E_INDEX Z3_E_INDEX
 #endif
+
+// The Z3 axis, if any, should be the next open extruder port
 #if NUM_Z_STEPPER_DRIVERS >= 3
   #ifndef Z3_STEP_PIN
     #define Z3_STEP_PIN   _EPIN(Z3_E_INDEX, STEP)
   #define Z3_MS3_PIN -1
 #endif
 
-// The Z4 axis, if any, should be the next open extruder port
 #if NUM_Z_STEPPER_DRIVERS >= 4 && !defined(Z4_DIAG_PIN) && !defined(Z4_STEP_PIN) && !PIN_EXISTS(Z4_CS_PIN)
   #define I_E_INDEX INCREMENT(Z4_E_INDEX)
 #else
   #define I_E_INDEX Z4_E_INDEX
 #endif
+
+// The Z4 axis, if any, should be the next open extruder port
 #if NUM_Z_STEPPER_DRIVERS >= 4
   #ifndef Z4_STEP_PIN
     #define Z4_STEP_PIN   _EPIN(Z4_E_INDEX, STEP)
   #define Z4_MS3_PIN -1
 #endif
 
-// The I axis, if any, should be the next open extruder port
 #if HAS_I_AXIS && !defined(I_DIAG_PIN) && !defined(I_STEP_PIN) && !PIN_EXISTS(I_CS_PIN)
   #define J_E_INDEX INCREMENT(I_E_INDEX)
 #else
   #define J_E_INDEX I_E_INDEX
 #endif
+
+// The I axis, if any, should be the next open extruder port
 #if HAS_I_AXIS
   #ifndef I_STEP_PIN
     #define I_STEP_PIN   _EPIN(I_E_INDEX, STEP)
   #define I_MS3_PIN -1
 #endif
 
-// The J axis, if any, should be the next open extruder port
 #if HAS_J_AXIS && !defined(J_DIAG_PIN) && !defined(J_STEP_PIN) && !PIN_EXISTS(J_CS_PIN)
   #define K_E_INDEX INCREMENT(J_E_INDEX)
 #else
   #define K_E_INDEX J_E_INDEX
 #endif
+
+// The J axis, if any, should be the next open extruder port
 #if HAS_J_AXIS
   #ifndef J_STEP_PIN
     #define J_STEP_PIN   _EPIN(J_E_INDEX, STEP)