Store and display FT_MOTION linearadvance as a float with 4 digit and 2 decimals

Marlin/Configuration_adv.h

@@ -1129,7 +1129,7 @@
   #define FTM_SHAPING_DEFAULT_X_FREQ   37.0f      // (Hz) Default peak frequency used by input shapers
   #define FTM_SHAPING_DEFAULT_Y_FREQ   37.0f      // (Hz) Default peak frequency used by input shapers
   #define FTM_LINEAR_ADV_DEFAULT_ENA   false      // Default linear advance enable (true) or disable (false)
-  #define FTM_LINEAR_ADV_DEFAULT_K      0.0f      // Default linear advance gain
+  #define FTM_LINEAR_ADV_DEFAULT_K      0         // Default linear advance gain, integer value. (Acceleration-based scaling factor.)
   #define FTM_SHAPING_ZETA_X            0.1f      // Zeta used by input shapers for X axis
   #define FTM_SHAPING_ZETA_Y            0.1f      // Zeta used by input shapers for Y axis
 

Marlin/src/lcd/menu/menu_motion.cpp

@@ -481,15 +481,18 @@ void menu_move() {
 
     ftm_menu_get_msg_strings();
 
+    ft_config_t &c = ftMotion.cfg;
+
     START_MENU();
-      SUBMENU(MSG_FTM_MODE, menu_ftm_mode);
-      MENU_ITEM_ADDON_START_RJ(ftmode.length()); lcd_put_u8str(ftmode); MENU_ITEM_ADDON_END();
+    SUBMENU(MSG_FTM_MODE, menu_ftm_mode);
+    MENU_ITEM_ADDON_START_RJ(ftmode.length()); lcd_put_u8str(ftmode); MENU_ITEM_ADDON_END();
     #if HAS_DYNAMIC_FREQ
       SUBMENU(MSG_FTM_DYN_MODE, menu_ftm_dyn_mode);
       MENU_ITEM_ADDON_START_RJ(dmode.length()); lcd_put_u8str(dmode); MENU_ITEM_ADDON_END();
     #endif
     #if HAS_EXTRUDERS
-      EDIT_ITEM(bool, MSG_LINEAR_ADVANCE, &ftMotion.cfg.linearAdvEna);
+      EDIT_ITEM(bool, MSG_LINEAR_ADVANCE, &c.linearAdvEna);
+      if (c.linearAdvEna) EDIT_ITEM(float62, MSG_ADVANCE_K, &c.linearAdvK, 0.0f, 1000.0f);
     #endif
 
     END_MENU();

Marlin/src/module/ft_motion.cpp

@@ -579,7 +579,7 @@ void FTMotion::makeVector() {
   #if HAS_EXTRUDERS
     if (cfg.linearAdvEna) {
       float dedt_adj = (traj.e[makeVector_batchIdx] - e_raw_z1) * (FTM_FS);
-      if (ratio.e > 0.0f) dedt_adj += accel_k * cfg.linearAdvK;
+      if (ratio.e > 0.0f) dedt_adj += accel_k * cfg.linearAdvK * 0.0001f;
 
       e_raw_z1 = traj.e[makeVector_batchIdx];
       e_advanced_z1 += dedt_adj * (FTM_TS);