Followup for 6 extruders

Marlin/src/gcode/feature/trinamic/M911-M915.cpp

       #endif
     #endif
 
-    #if M91x_USE_E(0) || M91x_USE_E(1) || M91x_USE_E(2) || M91x_USE_E(3) || M91x_USE_E(4)
-      const int8_t eval = int8_t(parser.byteval(axis_codes[E_AXIS], 0xFF));
+    #if M91x_USE_E(0) || M91x_USE_E(1) || M91x_USE_E(2) || M91x_USE_E(3) || M91x_USE_E(4) || M91x_USE_E(5)
+      const uint8_t eval = int8_t(parser.byteval(axis_codes[E_AXIS], 0xFF));
       #if M91x_USE_E(0)
         if (hasNone || eval == 0 || (hasE && eval < 0)) tmc_clear_otpw(stepperE0, TMC_E0);
       #endif
         if (hasNone || eval == 4 || (hasE && eval < 0)) tmc_clear_otpw(stepperE4, TMC_E4);
       #endif
       #if M91x_USE_E(5)
-        if (hasNone || eval == 5 || (hasE && eval == 10)) tmc_clear_otpw(stepperE5, TMC_E5);
+        if (hasNone || eval == 5 || (hasE && eval < 0)) tmc_clear_otpw(stepperE5, TMC_E5);
       #endif
     #endif
 }

Marlin/src/module/stepper_indirection.cpp

   #if AXIS_DRIVER_TYPE(E4, TMC26X)
     _TMC26X_DEFINE(E4);
   #endif
+  #if AXIS_DRIVER_TYPE(E5, TMC26X)
+    _TMC26X_DEFINE(E5);
+  #endif
 
   #define _TMC26X_INIT(A) do{ \
     stepper##A.setMicrosteps(A##_MICROSTEPS); \
     #if AXIS_DRIVER_TYPE(E4, TMC26X)
       _TMC26X_INIT(E4);
     #endif
+    #if AXIS_DRIVER_TYPE(E5, TMC26X)
+      _TMC26X_INIT(E5);
+    #endif
   }
 #endif // TMC26X
 
   #if AXIS_DRIVER_TYPE(E4, TMC2130)
     _TMC2130_DEFINE(E4);
   #endif
+  #if AXIS_DRIVER_TYPE(E5, TMC2130)
+    _TMC2130_DEFINE(E5);
+  #endif
 
   // Use internal reference voltage for current calculations. This is the default.
   // Following values from Trinamic's spreadsheet with values for a NEMA17 (42BYGHW609)
       _TMC2208_DEFINE_SOFTWARE(E4);
     #endif
   #endif
+  #if AXIS_DRIVER_TYPE(E5, TMC2208)
+    #ifdef E5_HARDWARE_SERIAL
+      _TMC2208_DEFINE_HARDWARE(E5);
+    #else
+      _TMC2208_DEFINE_SOFTWARE(E5);
+    #endif
+  #endif
 
   void tmc2208_serial_begin() {
     #if AXIS_DRIVER_TYPE(X, TMC2208)
         stepperE4.beginSerial(115200);
       #endif
     #endif
+    #if AXIS_DRIVER_TYPE(E5, TMC2208)
+      #ifdef E5_HARDWARE_SERIAL
+        E5_HARDWARE_SERIAL.begin(115200);
+      #else
+        stepperE5.beginSerial(115200);
+      #endif
+    #endif
   }
 
   // Use internal reference voltage for current calculations. This is the default.
   #if AXIS_IS_TMC(E4)
     stepperE4.push();
   #endif
+  #if AXIS_IS_TMC(E5)
+    stepperE5.push();
+  #endif
 }
 
 void reset_stepper_drivers() {
   #if AXIS_DRIVER_TYPE(E4, L6470)
     _L6470_DEFINE(E4);
   #endif
+  #if AXIS_DRIVER_TYPE(E5, L6470)
+    _L6470_DEFINE(E5);
+  #endif
 
   #define _L6470_INIT(A) do{ \
     stepper##A.init(); \
     #if AXIS_DRIVER_TYPE(E4, L6470)
       _L6470_INIT(E4);
     #endif
+    #if AXIS_DRIVER_TYPE(E5, L6470)
+      _L6470_INIT(E5);
+    #endif
   }
 
 #endif // L6470