[WIP] feat(behaviors): Leader key

app/CMakeLists.txt

@@ -44,6 +44,7 @@ if ((NOT CONFIG_ZMK_SPLIT) OR CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
   target_sources(app PRIVATE src/behaviors/behavior_caps_word.c)
   target_sources(app PRIVATE src/behaviors/behavior_key_repeat.c)
   target_sources(app PRIVATE src/behaviors/behavior_macro.c)
+  target_sources_ifdef(CONFIG_ZMK_BEHAVIOR_LEADER_KEY app PRIVATE src/behaviors/behavior_leader_key.c)
   target_sources(app PRIVATE src/behaviors/behavior_momentary_layer.c)
   target_sources(app PRIVATE src/behaviors/behavior_mod_morph.c)
   target_sources(app PRIVATE src/behaviors/behavior_outputs.c)
@@ -54,6 +55,7 @@ if ((NOT CONFIG_ZMK_SPLIT) OR CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
   target_sources(app PRIVATE src/behaviors/behavior_none.c)
   target_sources(app PRIVATE src/behaviors/behavior_sensor_rotate_key_press.c)
   target_sources(app PRIVATE src/combo.c)
+  target_sources_ifdef(CONFIG_ZMK_LEADER app PRIVATE src/leader.c)
   target_sources(app PRIVATE src/behavior_queue.c)
   target_sources(app PRIVATE src/conditional_layer.c)
   target_sources(app PRIVATE src/endpoints.c)

app/Kconfig

@@ -331,6 +331,19 @@ config ZMK_COMBO_MAX_KEYS_PER_COMBO
 #Combo options
 endmenu
 
+menu "Leader Options"
+
+config ZMK_LEADER_MAX_KEYS_PER_SEQUENCE
+    int "Maximum number of key presses in a leader sequence"
+    default 4
+
+config ZMK_LEADER_MAX_SEQUENCES_PER_KEY
+    int "Maximum number of leader sequences that a key can belong to"
+    default 5
+
+#Leader options
+endmenu
+
 menu "Behavior Options"
 
 config ZMK_BEHAVIORS_QUEUE_SIZE
@@ -343,6 +356,18 @@ config ZMK_BEHAVIOR_KEY_TOGGLE
         bool
         default $(dt_compat_enabled,$(DT_COMPAT_ZMK_BEHAVIOR_KEY_TOGGLE))
 
+DT_COMPAT_ZMK_LEADER := zmk,leader-sequences
+
+config ZMK_LEADER
+        bool
+        default $(dt_compat_enabled,$(DT_COMPAT_ZMK_LEADER))
+
+DT_COMPAT_ZMK_BEHAVIOR_LEADER_KEY := zmk,behavior-leader-key
+
+config ZMK_BEHAVIOR_LEADER_KEY
+        bool
+        default $(dt_compat_enabled,$(DT_COMPAT_ZMK_BEHAVIOR_LEADER_KEY))
+
 endmenu
 
 menu "Advanced"

app/dts/behaviors.dtsi

@@ -18,4 +18,5 @@
 #include <behaviors/caps_word.dtsi>
 #include <behaviors/key_repeat.dtsi>
 #include <behaviors/backlight.dtsi>
-#include <behaviors/macros.dtsi>
+#include <behaviors/macros.dtsi>
+#include <behaviors/leader_key.dtsi>

app/dts/behaviors/leader_key.dtsi

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2022 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+ / {
+	behaviors {
+		/omit-if-no-ref/ leader: leader_key {
+			compatible = "zmk,behavior-leader-key";
+			label = "LEADER";
+			#binding-cells = <0>;
+		};
+	};
+};

app/dts/bindings/behaviors/zmk,behavior-leader-key.yaml

@@ -0,0 +1,13 @@
+# Copyright (c) 2022 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Leader key behavior
+
+compatible: "zmk,behavior-leader-key"
+
+include: zero_param.yaml
+
+properties:
+  timeout-ms:
+    type: int
+    default: -1

app/dts/bindings/zmk,leader-sequences.yaml

@@ -0,0 +1,22 @@
+# Copyright (c) 2022, The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Leader sequence container
+
+compatible: "zmk,leader-sequences"
+
+child-binding:
+  description: "A leader sequence"
+
+  properties:
+    bindings:
+      type: phandle-array
+      required: true
+    key-positions:
+      type: array
+      required: true
+    layers:
+      type: array
+      default: [-1]
+    immediate-trigger:
+      type: boolean

app/include/zmk/leader.h

@@ -0,0 +1,11 @@
+/*
+ * Copyright (c) 2022 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+void zmk_leader_activate(int32_t timeout, uint32_t position);
+void zmk_leader_deactivate();
+bool zmk_leader_get_status();

app/src/behaviors/behavior_leader_key.c

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2022 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_leader_key
+
+#include <device.h>
+#include <drivers/behavior.h>
+#include <logging/log.h>
+
+#include <zmk/hid.h>
+#include <zmk/event_manager.h>
+#include <zmk/events/keycode_state_changed.h>
+#include <zmk/behavior.h>
+#include <zmk/leader.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+struct behavior_leader_key_config {
+    int32_t timeout_ms;
+};
+
+static int behavior_leader_key_init(const struct device *dev) { return 0; }
+
+static int on_keymap_binding_pressed(struct zmk_behavior_binding *binding,
+                                     struct zmk_behavior_binding_event event) {
+    const struct device *dev = device_get_binding(binding->behavior_dev);
+    const struct behavior_leader_key_config *cfg = dev->config;
+
+    zmk_leader_activate(cfg->timeout_ms, event.position);
+    return ZMK_BEHAVIOR_OPAQUE;
+}
+
+static int on_keymap_binding_released(struct zmk_behavior_binding *binding,
+                                      struct zmk_behavior_binding_event event) {
+    return 0;
+}
+
+static const struct behavior_driver_api behavior_leader_key_driver_api = {
+    .binding_pressed = on_keymap_binding_pressed,
+    .binding_released = on_keymap_binding_released,
+};
+
+#define LEAD_INST(n)                                                                               \
+    static struct behavior_leader_key_config behavior_leader_key_config_##n = {                    \
+        .timeout_ms = DT_INST_PROP(n, timeout_ms)};                                                \
+    DEVICE_DT_INST_DEFINE(n, behavior_leader_key_init, NULL, NULL,                                 \
+                          &behavior_leader_key_config_##n, APPLICATION,                            \
+                          CONFIG_KERNEL_INIT_PRIORITY_DEFAULT, &behavior_leader_key_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(LEAD_INST)