Beginning work of Tap Dance

app/CMakeLists.txt

@@ -46,6 +46,7 @@ if ((NOT CONFIG_ZMK_SPLIT) OR CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
   target_sources(app PRIVATE src/behaviors/behavior_key_toggle.c)
   target_sources(app PRIVATE src/behaviors/behavior_reset.c)
   target_sources(app PRIVATE src/behaviors/behavior_hold_tap.c)
+  target_sources(app PRIVATE src/behaviors/behavior_tap_dance.c)
   target_sources(app PRIVATE src/behaviors/behavior_sticky_key.c)
   target_sources(app PRIVATE src/behaviors/behavior_momentary_layer.c)
   target_sources(app PRIVATE src/behaviors/behavior_mod_morph.c)

app/dts/bindings/behaviors/zmk,behavior-tap-dance.yaml

@@ -0,0 +1,16 @@
+# Copyright (c) 2021 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Tap Dance Behavior
+
+compatible: "zmk,behavior-tap-dance"
+
+include: zero_param.yaml
+
+properties:
+  bindings:
+    type: phandle-array
+    required: true
+  tapping_term_ms:
+    type: int
+    default: 175

app/src/behaviors/behavior_tap_dance.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2021 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_tap_dance
+
+#include <device.h>
+#include <drivers/behavior.h>
+#include <logging/log.h>
+#include <zmk/behavior.h>
+
+#include <zmk/matrix.h>
+#include <zmk/event_manager.h>
+#include <zmk/events/keycode_state_changed.h>
+#include <zmk/hid.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
+
+static bool tap_dance_started = false;
+static int tap_counter = 0; 
+int64_t timestamp;
+
+struct behavior_tap_dance_config {    
+    int tapping_term_ms;
+};
+
+static int on_tap_dance_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_tap_dance_config *cfg = dev->config;
+    if (!tap_dance_started) {
+        tap_dance_started = true;
+        timestamp = k_uptime_get();
+        LOG_DBG("timestamp at: %lld", timestamp);
+    }
+    else {
+        if (k_uptime_get() <= (timestamp + cfg->tapping_term_ms)){
+            timestamp = k_uptime_get();
+            LOG_DBG("Updated timestamp: %lld", timestamp);
+        }
+    }
+    int32_t tapping_term_ms_left = (timestamp + cfg->tapping_term_ms) - k_uptime_get();
+    LOG_DBG("time left: %d", tapping_term_ms_left);
+
+    if (tapping_term_ms_left <= 0) {
+        LOG_DBG("TIME'S UP");
+        LOG_DBG("Counter reached on press: %d", tap_counter);
+        tap_dance_started = false;
+        tap_counter = 0;
+    }
+    else {
+        ++ tap_counter;
+    }             
+    LOG_DBG("Counter beginning at: %d", tap_counter);
+    
+
+    return ZMK_BEHAVIOR_OPAQUE;
+
+    
+}
+
+static int on_tap_dance_binding_released(struct zmk_behavior_binding *binding,
+                                      struct zmk_behavior_binding_event event) {
+    const struct device *dev = device_get_binding(binding->behavior_dev);
+    const struct behavior_tap_dance_config *cfg = dev->config;
+    int32_t tapping_term_ms_left = (timestamp + cfg->tapping_term_ms) - k_uptime_get();
+    if (tapping_term_ms_left <= 0) {
+        LOG_DBG("Counter reached on release: %d", tap_counter);
+        tap_dance_started = false;
+        tap_counter = 0;
+    }
+    return ZMK_BEHAVIOR_OPAQUE;
+}
+
+static const struct behavior_driver_api behavior_tap_dance_driver_api = {
+    .binding_pressed = on_tap_dance_binding_pressed,
+    .binding_released = on_tap_dance_binding_released,
+};
+
+static int behavior_tap_dance_init(const struct device *dev) { return 0; };
+
+struct behavior_tap_dance_data {};
+static struct behavior_tap_dance_data behavior_tap_dance_data;
+
+#define KP_INST(n)                                                                                                         \
+    static struct behavior_tap_dance_config behavior_tap_dance_config_##n = {                                              \
+        .tapping_term_ms = DT_INST_PROP(n, tapping_term_ms),                                                                                                           \
+    };                                                                                                                     \
+    DEVICE_AND_API_INIT(behavior_tap_dance_##n, DT_INST_LABEL(n), behavior_tap_dance_init, &behavior_tap_dance_data,       \
+                        &behavior_tap_dance_config_##n, APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,                  \
+                        &behavior_tap_dance_driver_api);
+    
+DT_INST_FOREACH_STATUS_OKAY(KP_INST)
+
+#endif