From 5fe1f6647875b2f325db52b74f356bdaec19dce5 Mon Sep 17 00:00:00 2001
From: Giuliano Zaro <3684609+GMagician@users.noreply.github.com>
Date: Thu, 1 Sep 2022 21:16:52 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=9A=B8=20Strict=20index=202=20for=20M913?=
 =?UTF-8?q?=20/=20M914=20XY=20(#24680)?=
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---
 Marlin/src/gcode/feature/trinamic/M911-M914.cpp | 9 ++++-----
 Marlin/src/inc/SanityCheck.h                    | 6 ++++++
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/Marlin/src/gcode/feature/trinamic/M911-M914.cpp b/Marlin/src/gcode/feature/trinamic/M911-M914.cpp
index 0a9d1760e9..0fbf1def67 100644
--- a/Marlin/src/gcode/feature/trinamic/M911-M914.cpp
+++ b/Marlin/src/gcode/feature/trinamic/M911-M914.cpp
@@ -294,14 +294,14 @@
         #if X_HAS_STEALTHCHOP || X2_HAS_STEALTHCHOP
           case X_AXIS:
             TERN_(X_HAS_STEALTHCHOP,  if (index < 2) TMC_SET_PWMTHRS(X,X));
-            TERN_(X2_HAS_STEALTHCHOP, if (!(index & 1)) TMC_SET_PWMTHRS(X,X2));
+            TERN_(X2_HAS_STEALTHCHOP, if (!index || index == 2) TMC_SET_PWMTHRS(X,X2));
             break;
         #endif
 
         #if Y_HAS_STEALTHCHOP || Y2_HAS_STEALTHCHOP
           case Y_AXIS:
             TERN_(Y_HAS_STEALTHCHOP,  if (index < 2) TMC_SET_PWMTHRS(Y,Y));
-            TERN_(Y2_HAS_STEALTHCHOP, if (!(index & 1)) TMC_SET_PWMTHRS(Y,Y2));
+            TERN_(Y2_HAS_STEALTHCHOP, if (!index || index == 2) TMC_SET_PWMTHRS(Y,Y2));
             break;
         #endif
 
@@ -499,7 +499,6 @@
    * M914: Set StallGuard sensitivity.
    */
   void GcodeSuite::M914() {
-
     bool report = true;
     const uint8_t index = parser.byteval('I');
     LOOP_NUM_AXES(i) if (parser.seen(AXIS_CHAR(i))) {
@@ -509,13 +508,13 @@
         #if X_SENSORLESS
           case X_AXIS:
             if (index < 2) stepperX.homing_threshold(value);
-            TERN_(X2_SENSORLESS, if (!(index & 1)) stepperX2.homing_threshold(value));
+            TERN_(X2_SENSORLESS, if (!index || index == 2) stepperX2.homing_threshold(value));
             break;
         #endif
         #if Y_SENSORLESS
           case Y_AXIS:
             if (index < 2) stepperY.homing_threshold(value);
-            TERN_(Y2_SENSORLESS, if (!(index & 1)) stepperY2.homing_threshold(value));
+            TERN_(Y2_SENSORLESS, if (!index || index == 2) stepperY2.homing_threshold(value));
             break;
         #endif
         #if Z_SENSORLESS
diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index ea39aa1b70..e9675feaf1 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -2044,6 +2044,12 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
   );
 #endif
 
+#define COUNT_SENSORLESS COUNT_ENABLED(Z_SENSORLESS, Z2_SENSORLESS, Z3_SENSORLESS, Z4_SENSORLESS)
+#if COUNT_SENSORLESS && COUNT_SENSORLESS != NUM_Z_STEPPERS
+  #error "All Z steppers must have *_STALL_SENSITIVITY defined to use Z sensorless homing."
+#endif
+#undef COUNT_SENSORLESS
+
 #ifdef SENSORLESS_BACKOFF_MM
   constexpr float sbm[] = SENSORLESS_BACKOFF_MM;
   static_assert(COUNT(sbm) == NUM_AXES, "SENSORLESS_BACKOFF_MM must have " _NUM_AXES_STR "elements (and no others).");