feat: Allow layer behaviors to "lock" layers on

app/dts/behaviors/to_layer.dtsi

@@ -15,6 +15,7 @@
             compatible = "zmk,behavior-to-layer";
             #binding-cells = <1>;
             display-name = "To Layer";
+            locking;
         };
     };
 };

app/dts/behaviors/toggle_layer.dtsi

@@ -15,6 +15,7 @@
             compatible = "zmk,behavior-toggle-layer";
             #binding-cells = <1>;
             display-name = "Toggle Layer";
+            locking;
         };
     };
 };

app/dts/bindings/behaviors/zmk,behavior-momentary-layer.yaml

@@ -6,3 +6,8 @@ description: Momentary layer on press/release behavior
 compatible: "zmk,behavior-momentary-layer"
 
 include: one_param.yaml
+
+properties:
+  locking:
+    type: boolean
+    description: Whether to "lock" the layer active, preventing behaviors without the "locking" property from deactivating the layer

app/dts/bindings/behaviors/zmk,behavior-to-layer.yaml

@@ -6,3 +6,8 @@ description: To Layer
 compatible: "zmk,behavior-to-layer"
 
 include: one_param.yaml
+
+properties:
+  locking:
+    type: boolean
+    description: Whether to "lock" the layer active, preventing behaviors without the "locking" property from deactivating the layer

app/dts/bindings/behaviors/zmk,behavior-toggle-layer.yaml

@@ -10,9 +10,11 @@ include: one_param.yaml
 properties:
   toggle-mode:
     type: string
-    required: false
     default: "flip"
     enum:
       - "on"
       - "off"
       - "flip"
+  locking:
+    type: boolean
+    description: Whether to "lock" the layer active, preventing behaviors without the "locking" property from deactivating the layer

app/include/zmk/keymap.h

@@ -35,10 +35,10 @@ zmk_keymap_layer_id_t zmk_keymap_layer_default(void);
 zmk_keymap_layers_state_t zmk_keymap_layer_state(void);
 bool zmk_keymap_layer_active(zmk_keymap_layer_id_t layer);
 zmk_keymap_layer_index_t zmk_keymap_highest_layer_active(void);
-int zmk_keymap_layer_activate(zmk_keymap_layer_id_t layer);
-int zmk_keymap_layer_deactivate(zmk_keymap_layer_id_t layer);
-int zmk_keymap_layer_toggle(zmk_keymap_layer_id_t layer);
-int zmk_keymap_layer_to(zmk_keymap_layer_id_t layer);
+int zmk_keymap_layer_activate(zmk_keymap_layer_id_t layer, bool locking);
+int zmk_keymap_layer_deactivate(zmk_keymap_layer_id_t layer, bool locking);
+int zmk_keymap_layer_toggle(zmk_keymap_layer_id_t layer, bool locking);
+int zmk_keymap_layer_to(zmk_keymap_layer_id_t layer, bool locking);
 const char *zmk_keymap_layer_name(zmk_keymap_layer_id_t layer);
 
 const struct zmk_behavior_binding *zmk_keymap_get_layer_binding_at_idx(zmk_keymap_layer_id_t layer,

app/src/behaviors/behavior_momentary_layer.c

@@ -36,21 +36,25 @@ static const struct behavior_parameter_metadata metadata = {
 
 #endif
 
-struct behavior_mo_config {};
 struct behavior_mo_data {};
+struct behavior_mo_config {
+    bool locking;
+};
 
 static int behavior_mo_init(const struct device *dev) { return 0; };
 
 static int mo_keymap_binding_pressed(struct zmk_behavior_binding *binding,
                                      struct zmk_behavior_binding_event event) {
     LOG_DBG("position %d layer %d", event.position, binding->param1);
-    return zmk_keymap_layer_activate(binding->param1);
+    const struct behavior_mo_config *cfg = zmk_behavior_get_binding(binding->behavior_dev)->config;
+    return zmk_keymap_layer_activate(binding->param1, cfg->locking);
 }
 
 static int mo_keymap_binding_released(struct zmk_behavior_binding *binding,
                                       struct zmk_behavior_binding_event event) {
     LOG_DBG("position %d layer %d", event.position, binding->param1);
-    return zmk_keymap_layer_deactivate(binding->param1);
+    const struct behavior_mo_config *cfg = zmk_behavior_get_binding(binding->behavior_dev)->config;
+    return zmk_keymap_layer_deactivate(binding->param1, cfg->locking);
 }
 
 static const struct behavior_driver_api behavior_mo_driver_api = {
@@ -61,9 +65,14 @@ static const struct behavior_driver_api behavior_mo_driver_api = {
 #endif // IS_ENABLED(CONFIG_ZMK_BEHAVIOR_METADATA)
 };
 
-static const struct behavior_mo_config behavior_mo_config = {};
-
 static struct behavior_mo_data behavior_mo_data;
 
-BEHAVIOR_DT_INST_DEFINE(0, behavior_mo_init, NULL, &behavior_mo_data, &behavior_mo_config,
-                        POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT, &behavior_mo_driver_api);
+#define KT_INST(n)                                                                                 \
+    static const struct behavior_mo_config behavior_mo_config_##n = {                              \
+        .locking = DT_INST_PROP_OR(n, locking, false),                                             \
+    };                                                                                             \
+    BEHAVIOR_DT_INST_DEFINE(n, behavior_mo_init, NULL, &behavior_mo_data, &behavior_mo_config_##n, \
+                            POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,                      \
+                            &behavior_mo_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(KT_INST)

app/src/behaviors/behavior_to_layer.c

@@ -17,12 +17,17 @@ LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
 #if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
 
+struct behavior_to_config {
+    bool locking;
+};
+
 static int behavior_to_init(const struct device *dev) { return 0; };
 
 static int to_keymap_binding_pressed(struct zmk_behavior_binding *binding,
                                      struct zmk_behavior_binding_event event) {
     LOG_DBG("position %d layer %d", event.position, binding->param1);
-    zmk_keymap_layer_to(binding->param1);
+    const struct behavior_to_config *cfg = zmk_behavior_get_binding(binding->behavior_dev)->config;
+    zmk_keymap_layer_to(binding->param1, cfg->locking);
     return ZMK_BEHAVIOR_OPAQUE;
 }
 
@@ -61,7 +66,13 @@ static const struct behavior_driver_api behavior_to_driver_api = {
 #endif // IS_ENABLED(CONFIG_ZMK_BEHAVIOR_METADATA)
 };
 
-BEHAVIOR_DT_INST_DEFINE(0, behavior_to_init, NULL, NULL, NULL, POST_KERNEL,
-                        CONFIG_KERNEL_INIT_PRIORITY_DEFAULT, &behavior_to_driver_api);
+#define KT_INST(n)                                                                                 \
+    static const struct behavior_to_config behavior_to_config_##n = {                              \
+        .locking = DT_INST_PROP_OR(n, locking, false),                                             \
+    };                                                                                             \
+    BEHAVIOR_DT_INST_DEFINE(n, behavior_to_init, NULL, NULL, &behavior_to_config_##n, POST_KERNEL, \
+                            CONFIG_KERNEL_INIT_PRIORITY_DEFAULT, &behavior_to_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(KT_INST)
 
 #endif /* DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT) */

app/src/behaviors/behavior_toggle_layer.c

@@ -25,6 +25,7 @@ enum toggle_mode {
 
 struct behavior_tog_config {
     enum toggle_mode toggle_mode;
+    bool locking;
 };
 
 static int behavior_tog_init(const struct device *dev) { return 0; };
@@ -36,11 +37,11 @@ static int tog_keymap_binding_pressed(struct zmk_behavior_binding *binding,
     const struct behavior_tog_config *cfg = zmk_behavior_get_binding(binding->behavior_dev)->config;
     switch (cfg->toggle_mode) {
     case ON:
-        return zmk_keymap_layer_activate(binding->param1);
+        return zmk_keymap_layer_activate(binding->param1, cfg->locking);
     case OFF:
-        return zmk_keymap_layer_deactivate(binding->param1);
+        return zmk_keymap_layer_deactivate(binding->param1, cfg->locking);
     case FLIP:
-        return zmk_keymap_layer_toggle(binding->param1);
+        return zmk_keymap_layer_toggle(binding->param1, cfg->locking);
     default:
         return -ENOTSUP;
     };
@@ -84,6 +85,7 @@ static const struct behavior_driver_api behavior_tog_driver_api = {
 #define KT_INST(n)                                                                                 \
     static const struct behavior_tog_config behavior_tog_config_##n = {                            \
         .toggle_mode = DT_ENUM_IDX(DT_DRV_INST(n), toggle_mode),                                   \
+        .locking = DT_INST_PROP_OR(n, locking, false),                                             \
     };                                                                                             \
     BEHAVIOR_DT_INST_DEFINE(n, behavior_tog_init, NULL, NULL, &behavior_tog_config_##n,            \
                             POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,                      \

app/src/conditional_layer.c

@@ -54,7 +54,7 @@ static void conditional_layer_activate(int8_t layer) {
     // the process will eventually terminate (at worst, when every layer is active).
     if (!zmk_keymap_layer_active(layer)) {
         LOG_DBG("layer %d", layer);
-        zmk_keymap_layer_activate(layer);
+        zmk_keymap_layer_activate(layer, false);
     }
 }
 
@@ -64,7 +64,7 @@ static void conditional_layer_deactivate(int8_t layer) {
     // &mo binding are held and then one is released, so it's probably not an issue in practice.
     if (zmk_keymap_layer_active(layer)) {
         LOG_DBG("layer %d", layer);
-        zmk_keymap_layer_deactivate(layer);
+        zmk_keymap_layer_deactivate(layer, false);
     }
 }
 

app/src/keymap.c

@@ -23,6 +23,7 @@ LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 #include <zmk/events/layer_state_changed.h>
 #include <zmk/events/sensor_event.h>
 
+static zmk_keymap_layers_state_t _zmk_keymap_layer_locks = 0;
 static zmk_keymap_layers_state_t _zmk_keymap_layer_state = 0;
 static zmk_keymap_layer_id_t _zmk_keymap_layer_default = 0;
 
@@ -131,7 +132,7 @@ uint8_t map_layer_id_to_index(zmk_keymap_layer_id_t layer_id) {
 
 #endif // IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING)
 
-static inline int set_layer_state(zmk_keymap_layer_id_t layer_id, bool state) {
+static inline int set_layer_state(zmk_keymap_layer_id_t layer_id, bool state, bool locking) {
     int ret = 0;
     if (layer_id >= ZMK_KEYMAP_LAYERS_LEN) {
         return -EINVAL;
@@ -142,11 +143,21 @@ static inline int set_layer_state(zmk_keymap_layer_id_t layer_id, bool state) {
         return 0;
     }
 
+    // Non-forcing disables should not change a locked active layer
+    if (!locking && !state && ((_zmk_keymap_layer_locks >> layer_id) & 1)) {
+        return ret;
+    }
+
     zmk_keymap_layers_state_t old_state = _zmk_keymap_layer_state;
+    zmk_keymap_layers_state_t old_locks = _zmk_keymap_layer_locks;
     WRITE_BIT(_zmk_keymap_layer_state, layer_id, state);
+    if (locking) {
+        WRITE_BIT(_zmk_keymap_layer_locks, layer_id, state);
+    }
     // Don't send state changes unless there was an actual change
     if (old_state != _zmk_keymap_layer_state) {
         LOG_DBG("layer_changed: layer %d state %d", layer_id, state);
+
         ret = raise_layer_state_changed(layer_id, state);
         if (ret < 0) {
             LOG_WRN("Failed to raise layer state changed (%d)", ret);
@@ -193,26 +204,28 @@ zmk_keymap_layer_index_t zmk_keymap_highest_layer_active(void) {
     return LAYER_ID_TO_INDEX(zmk_keymap_layer_default());
 }
 
-int zmk_keymap_layer_activate(zmk_keymap_layer_id_t layer) { return set_layer_state(layer, true); };
+int zmk_keymap_layer_activate(zmk_keymap_layer_id_t layer, bool locking) {
+    return set_layer_state(layer, true, locking);
+};
 
-int zmk_keymap_layer_deactivate(zmk_keymap_layer_id_t layer) {
-    return set_layer_state(layer, false);
+int zmk_keymap_layer_deactivate(zmk_keymap_layer_id_t layer, bool locking) {
+    return set_layer_state(layer, false, locking);
 };
 
-int zmk_keymap_layer_toggle(zmk_keymap_layer_id_t layer) {
+int zmk_keymap_layer_toggle(zmk_keymap_layer_id_t layer, bool locking) {
     if (zmk_keymap_layer_active(layer)) {
-        return zmk_keymap_layer_deactivate(layer);
+        return zmk_keymap_layer_deactivate(layer, locking);
     }
 
-    return zmk_keymap_layer_activate(layer);
+    return zmk_keymap_layer_activate(layer, locking);
 };
 
-int zmk_keymap_layer_to(zmk_keymap_layer_id_t layer) {
+int zmk_keymap_layer_to(zmk_keymap_layer_id_t layer, bool locking) {
     for (int i = ZMK_KEYMAP_LAYERS_LEN - 1; i >= 0; i--) {
-        zmk_keymap_layer_deactivate(i);
+        zmk_keymap_layer_deactivate(i, locking);
     }
 
-    zmk_keymap_layer_activate(layer);
+    zmk_keymap_layer_activate(layer, locking);
 
     return 0;
 }

app/src/pointing/input_processor_temp_layer.c

@@ -70,10 +70,10 @@ static void update_layer_state(struct temp_layer_state *state, bool activate) {
 
     state->is_active = activate;
     if (activate) {
-        zmk_keymap_layer_activate(state->toggle_layer);
+        zmk_keymap_layer_activate(state->toggle_layer, false);
         LOG_DBG("Layer %d activated", state->toggle_layer);
     } else {
-        zmk_keymap_layer_deactivate(state->toggle_layer);
+        zmk_keymap_layer_deactivate(state->toggle_layer, false);
         LOG_DBG("Layer %d deactivated", state->toggle_layer);
     }
 }

app/tests/conditional-layer/locked-layers/events.patterns

@@ -0,0 +1,4 @@
+s/.*hid_listener_keycode/kp/p
+s/.*mo_keymap_binding/mo/p
+s/.*tog_keymap_binding/tog/p
+s/.*conditional_layer/cl/p

app/tests/conditional-layer/locked-layers/keycode_events.snapshot

@@ -0,0 +1,21 @@
+kp_pressed: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+kp_released: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+tog_pressed: position 2 layer 1
+tog_released: position 2 layer 1
+kp_pressed: usage_page 0x07 keycode 0x05 implicit_mods 0x00 explicit_mods 0x00
+kp_released: usage_page 0x07 keycode 0x05 implicit_mods 0x00 explicit_mods 0x00
+tog_pressed: position 3 layer 2
+cl_activate: layer 3
+tog_released: position 3 layer 2
+kp_pressed: usage_page 0x07 keycode 0x07 implicit_mods 0x00 explicit_mods 0x00
+kp_released: usage_page 0x07 keycode 0x07 implicit_mods 0x00 explicit_mods 0x00
+mo_pressed: position 1 layer 3
+mo_released: position 1 layer 3
+cl_activate: layer 3
+kp_pressed: usage_page 0x07 keycode 0x07 implicit_mods 0x00 explicit_mods 0x00
+kp_released: usage_page 0x07 keycode 0x07 implicit_mods 0x00 explicit_mods 0x00
+tog_pressed: position 2 layer 1
+cl_deactivate: layer 3
+tog_released: position 2 layer 1
+kp_pressed: usage_page 0x07 keycode 0x06 implicit_mods 0x00 explicit_mods 0x00
+kp_released: usage_page 0x07 keycode 0x06 implicit_mods 0x00 explicit_mods 0x00

app/tests/conditional-layer/locked-layers/native_posix_64.keymap

@@ -0,0 +1,64 @@
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/keys.h>
+#include <dt-bindings/zmk/kscan_mock.h>
+
+/ {
+    conditional_layers {
+        compatible = "zmk,conditional-layers";
+        tri_layer {
+            if-layers = <1 2>;
+            then-layer = <3>;
+        };
+    };
+
+    keymap {
+        compatible = "zmk,keymap";
+        default_layer {
+            bindings = <
+                &kp A &mo 3
+                &tog 1 &tog 2
+            >;
+        };
+        layer_1 {
+            bindings = <
+                &kp B &trans
+                &trans &trans
+            >;
+        };
+        layer_2 {
+            bindings = <
+                &kp C &trans
+                &trans &trans
+            >;
+        };
+        layer_3 {
+            bindings = <
+                &kp D &trans
+                &trans &trans
+            >;
+        };
+    };
+};
+
+&kscan {
+    events = <
+        ZMK_MOCK_PRESS(0,0,10)
+        ZMK_MOCK_RELEASE(0,0,10)
+        ZMK_MOCK_PRESS(1,0,10)
+        ZMK_MOCK_RELEASE(1,0,10)
+        ZMK_MOCK_PRESS(0,0,10)
+        ZMK_MOCK_RELEASE(0,0,10)
+        ZMK_MOCK_PRESS(1,1,10)
+        ZMK_MOCK_RELEASE(1,1,10)
+        ZMK_MOCK_PRESS(0,0,10)
+        ZMK_MOCK_RELEASE(0,0,10)
+        ZMK_MOCK_PRESS(0,1,10)
+        ZMK_MOCK_RELEASE(0,1,10)
+        ZMK_MOCK_PRESS(0,0,10)
+        ZMK_MOCK_RELEASE(0,0,10)
+        ZMK_MOCK_PRESS(1,0,10)
+        ZMK_MOCK_RELEASE(1,0,10)
+        ZMK_MOCK_PRESS(0,0,10)
+        ZMK_MOCK_RELEASE(0,0,10)
+    >;
+};