Add MKS_GEN_L_V2 controller support (#15793)

Marlin/src/core/boards.h

@@ -100,6 +100,7 @@
 #define BOARD_HJC2560C_REV1           1144  // ADIMLab Gantry v1
 #define BOARD_HJC2560C_REV2           1145  // ADIMLab Gantry v2
 #define BOARD_TANGO                   1146  // BIQU Tango V1
+#define BOARD_MKS_GEN_L_V2            1147  // MKS GEN L V2
 
 //
 // RAMBo and derivatives

Marlin/src/pins/pins.h

@@ -182,6 +182,9 @@
   #include "ramps/pins_TT_OSCAR.h"              // ATmega2560                             env:megaatmega2560
 #elif MB(TANGO)
   #include "ramps/pins_TANGO.h"                 // ATmega2560                             env:megaatmega2560
+#elif MB(MKS_GEN_L_V2)
+  #include "ramps/pins_MKS_GEN_L_V2.h"          // ATmega2560                             env:megaatmega2560
+
 
 //
 // RAMBo and derivatives

Marlin/src/pins/ramps/pins_MKS_GEN_L_V2.h

@@ -0,0 +1,89 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2019 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+/**
+ * MKS GEN L V2 – Arduino Mega2560 with RAMPS v1.4 pin assignments
+ */
+
+#if HOTENDS > 2 || E_STEPPERS > 2
+  #error "MKS GEN L V2 supports up to 2 hotends / E-steppers. Comment out this line to continue."
+#endif
+
+#define BOARD_INFO_NAME "MKS GEN L V2"
+
+//
+// Heaters / Fans
+//
+// Power outputs EFBF or EFBE
+#define MOSFET_D_PIN           7
+
+//
+// CS Pins wired to avoid conflict with the LCD
+// See https://www.thingiverse.com/asset:66604
+//
+
+#ifndef X_CS_PIN
+  #define X_CS_PIN            63
+#endif
+
+#ifndef Y_CS_PIN
+  #define Y_CS_PIN            64
+#endif
+
+#ifndef Z_CS_PIN
+  #define Z_CS_PIN            65
+#endif
+
+#ifndef E0_CS_PIN
+  #define E0_CS_PIN           66
+#endif
+
+#ifndef E1_CS_PIN
+  #define E1_CS_PIN           21
+#endif
+
+// TMC2130 Diag Pins (currently just for reference)
+#define X_DIAG_PIN             3
+#define Y_DIAG_PIN            14
+#define Z_DIAG_PIN            18
+#define E0_DIAG_PIN            2
+#define E1_DIAG_PIN           15
+
+#ifndef SERVO1_PIN
+  #define SERVO1_PIN          12
+#endif
+#ifndef SERVO2_PIN
+  #define SERVO2_PIN          39
+#endif
+#ifndef SERVO3_PIN
+  #define SERVO3_PIN          32
+#endif
+
+#ifndef E1_SERIAL_TX_PIN
+  #define E1_SERIAL_TX_PIN    20
+#endif
+#ifndef E1_SERIAL_RX_PIN
+  #define E1_SERIAL_RX_PIN    21
+#endif
+ 
+#include "pins_RAMPS.h"