2 files changed, 10 insertions, 0 deletions

diff --git a/quantum/keymap_common.c b/quantum/keymap_common.c
index 8b09f93fc..9a412b66a 100644
--- a/quantum/keymap_common.c
+++ b/quantum/keymap_common.c
@@ -122,6 +122,11 @@ action_t action_for_key(uint8_t layer, keypos_t key)
         case QK_LAYER_TAP_TOGGLE ... QK_LAYER_TAP_TOGGLE_MAX:
             action.code = ACTION_LAYER_TAP_TOGGLE(keycode & 0xFF);
             break;
+        case QK_LAYER_MOD ... QK_LAYER_MOD_MAX:
+            mod = keycode & 0xF;
+            action_layer = (keycode >> 4) & 0xF;
+            action.code = ACTION_LAYER_MODS(action_layer, mod);
+            break;
         case QK_MOD_TAP ... QK_MOD_TAP_MAX:
             mod = mod_config((keycode >> 0x8) & 0x1F);
             action.code = ACTION_MODS_TAP_KEY(mod, keycode & 0xFF);
diff --git a/quantum/quantum_keycodes.h b/quantum/quantum_keycodes.h
index 4a5681c7e..8122bfe73 100644
--- a/quantum/quantum_keycodes.h
+++ b/quantum/quantum_keycodes.h
@@ -71,6 +71,8 @@ enum quantum_keycodes {
     QK_TAP_DANCE_MAX      = 0x57FF,
     QK_LAYER_TAP_TOGGLE   = 0x5800,
     QK_LAYER_TAP_TOGGLE_MAX = 0x58FF,
+    QK_LAYER_MOD          = 0x5900,
+    QK_LAYER_MOD_MAX      = 0x59FF,
 #ifdef STENO_ENABLE
     QK_STENO              = 0x5A00,
     QK_STENO_BOLT         = 0x5A30,
@@ -597,6 +599,9 @@ enum quantum_keycodes {
 // One-shot layer - 256 layer max
 #define OSL(layer) (layer | QK_ONE_SHOT_LAYER)
 
+// L-ayer M-od: Momentary switch layer with modifiers active - 16 layer max, left mods only
+#define LM(layer, mod) (QK_LAYER_MOD | (((layer) & 0xF) << 4) | ((mod) & 0xF))
+
 // One-shot mod
 #define OSM(mod) ((mod) | QK_ONE_SHOT_MOD)