fix: Improve startup time with proper settings loading.

* Avoid doing duplicate calls to setings_load_subtree, which iterates
  NVS fully each time under the hood, and instead use on settings_load
  later in the lifecycle.

app/Kconfig.behaviors

@@ -12,12 +12,16 @@ config ZMK_BEHAVIOR_LOCAL_IDS
 
 if ZMK_BEHAVIOR_LOCAL_IDS
 
+config ZMK_BEHAVIOR_LOCAL_IDS_IN_BINDINGS
+    bool "Track in behavior bindings"
+
 choice ZMK_BEHAVIOR_LOCAL_ID_TYPE
     prompt "Local ID Type"
 
 config ZMK_BEHAVIOR_LOCAL_ID_TYPE_SETTINGS_TABLE
     bool "Settings Table"
     depends on SETTINGS
+    select ZMK_BEHAVIOR_LOCAL_IDS_IN_BINDINGS
     help
       Use persistent entries in the settings subsystem to identify
       behaviors by local ID, which uses the device name to generate

app/include/zmk/behavior.h

@@ -11,7 +11,12 @@
 #define ZMK_BEHAVIOR_OPAQUE 0
 #define ZMK_BEHAVIOR_TRANSPARENT 1
 
+typedef uint16_t zmk_behavior_local_id_t;
+
 struct zmk_behavior_binding {
+#if IS_ENABLED(CONFIG_ZMK_BEHAVIOR_LOCAL_IDS_IN_BINDINGS)
+    zmk_behavior_local_id_t local_id;
+#endif // IS_ENABLED(CONFIG_ZMK_BEHAVIOR_LOCAL_IDS_IN_BINDINGS)
     const char *behavior_dev;
     uint32_t param1;
     uint32_t param2;
@@ -23,8 +28,6 @@ struct zmk_behavior_binding_event {
     int64_t timestamp;
 };
 
-typedef uint16_t zmk_behavior_local_id_t;
-
 /**
  * @brief Get a const struct device* for a behavior from its @p name field.
  *

app/src/backlight.c

@@ -71,6 +71,9 @@ static int backlight_settings_load_cb(const char *name, size_t len, settings_rea
     return -ENOENT;
 }
 
+SETTINGS_STATIC_HANDLER_DEFINE(backlight, "backlight", NULL, backlight_settings_load_cb, NULL,
+                               NULL);
+
 static void backlight_save_work_handler(struct k_work *work) {
     settings_save_one("backlight/state", &state, sizeof(state));
 }
@@ -85,11 +88,6 @@ static int zmk_backlight_init(void) {
     }
 
 #if IS_ENABLED(CONFIG_SETTINGS)
-    settings_subsys_init();
-    int rc = settings_load_subtree_direct("backlight", backlight_settings_load_cb, NULL);
-    if (rc != 0) {
-        LOG_ERR("Failed to load backlight settings: %d", rc);
-    }
     k_work_init_delayable(&backlight_save_work, backlight_save_work_handler);
 #endif
 #if IS_ENABLED(CONFIG_ZMK_BACKLIGHT_AUTO_OFF_USB)

app/src/behavior.c

@@ -229,6 +229,8 @@ static int behavior_local_id_init(void) {
     return 0;
 }
 
+SYS_INIT(behavior_local_id_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);
+
 #elif IS_ENABLED(CONFIG_ZMK_BEHAVIOR_LOCAL_ID_TYPE_SETTINGS_TABLE)
 
 static zmk_behavior_local_id_t largest_local_id = 0;
@@ -239,7 +241,7 @@ static int behavior_handle_set(const char *name, size_t len, settings_read_cb re
 
     if (settings_name_steq(name, "local_id", &next) && next) {
         char *endptr;
-        uint8_t local_id = strtoul(next, &endptr, 10);
+        zmk_behavior_local_id_t local_id = strtoul(next, &endptr, 10);
         if (*endptr != '\0') {
             LOG_WRN("Invalid behavior local ID: %s with endptr %s", next, endptr);
             return -EINVAL;
@@ -302,22 +304,12 @@ static int behavior_handle_commit(void) {
 SETTINGS_STATIC_HANDLER_DEFINE(behavior, "behavior", NULL, behavior_handle_set,
                                behavior_handle_commit, NULL);
 
-static int behavior_local_id_init(void) {
-    settings_subsys_init();
-
-    settings_load_subtree("behavior");
-
-    return 0;
-}
-
 #else
 
 #error "A behavior local ID mechanism must be selected"
 
 #endif
 
-SYS_INIT(behavior_local_id_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);
-
 #endif
 
 #if IS_ENABLED(CONFIG_LOG)

app/src/ble.c

@@ -445,7 +445,11 @@ static int ble_profiles_handle_set(const char *name, size_t len, settings_read_c
     return 0;
 };
 
-struct settings_handler profiles_handler = {.name = "ble", .h_set = ble_profiles_handle_set};
+static int zmk_ble_complete_startup(void);
+
+static struct settings_handler profiles_handler = {
+    .name = "ble", .h_set = ble_profiles_handle_set, .h_commit = zmk_ble_complete_startup};
+
 #endif /* IS_ENABLED(CONFIG_SETTINGS) */
 
 static bool is_conn_active_profile(const struct bt_conn *conn) {
@@ -644,29 +648,7 @@ static void zmk_ble_ready(int err) {
     update_advertising();
 }
 
-static int zmk_ble_init(void) {
-    int err = bt_enable(NULL);
-
-    if (err) {
-        LOG_ERR("BLUETOOTH FAILED (%d)", err);
-        return err;
-    }
-
-#if IS_ENABLED(CONFIG_SETTINGS)
-    settings_subsys_init();
-
-    err = settings_register(&profiles_handler);
-    if (err) {
-        LOG_ERR("Failed to setup the profile settings handler (err %d)", err);
-        return err;
-    }
-
-    k_work_init_delayable(&ble_save_work, ble_save_profile_work);
-
-    settings_load_subtree("ble");
-    settings_load_subtree("bt");
-
-#endif
+static int zmk_ble_complete_startup(void) {
 
 #if IS_ENABLED(CONFIG_ZMK_BLE_CLEAR_BONDS_ON_START)
     LOG_WRN("Clearing all existing BLE bond information from the keyboard");
@@ -706,6 +688,24 @@ static int zmk_ble_init(void) {
     return 0;
 }
 
+static int zmk_ble_init(void) {
+    int err = bt_enable(NULL);
+
+    if (err < 0 && err != -EALREADY) {
+        LOG_ERR("BLUETOOTH FAILED (%d)", err);
+        return err;
+    }
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+    settings_register(&profiles_handler);
+    k_work_init_delayable(&ble_save_work, ble_save_profile_work);
+#else
+    zmk_ble_complete_startup();
+#endif
+
+    return 0;
+}
+
 #if IS_ENABLED(CONFIG_ZMK_BLE_PASSKEY_ENTRY)
 
 static bool zmk_ble_numeric_usage_to_value(const zmk_key_t key, const zmk_key_t one,

app/src/endpoints.c

@@ -263,7 +263,8 @@ static int endpoints_handle_set(const char *name, size_t len, settings_read_cb r
     return 0;
 }
 
-struct settings_handler endpoints_handler = {.name = "endpoints", .h_set = endpoints_handle_set};
+SETTINGS_STATIC_HANDLER_DEFINE(endpoints, "endpoints", NULL, endpoints_handle_set, NULL, NULL);
+
 #endif /* IS_ENABLED(CONFIG_SETTINGS) */
 
 static bool is_usb_ready(void) {
@@ -322,17 +323,7 @@ static struct zmk_endpoint_instance get_selected_instance(void) {
 
 static int zmk_endpoints_init(void) {
 #if IS_ENABLED(CONFIG_SETTINGS)
-    settings_subsys_init();
-
-    int err = settings_register(&endpoints_handler);
-    if (err) {
-        LOG_ERR("Failed to register the endpoints settings handler (err %d)", err);
-        return err;
-    }
-
     k_work_init_delayable(&endpoints_save_work, endpoints_save_preferred_work);
-
-    settings_load_subtree("endpoints");
 #endif
 
     current_instance = get_selected_instance();

app/src/ext_power_generic.c

@@ -121,12 +121,27 @@ static int ext_power_settings_set(const char *name, size_t len, settings_read_cb
     return -ENOENT;
 }
 
-struct settings_handler ext_power_conf = {.name = "ext_power/state",
-                                          .h_set = ext_power_settings_set};
+static int ext_power_settings_commit() {
+    const struct device *dev = DEVICE_DT_GET(DT_DRV_INST(0));
+    struct ext_power_generic_data *data = dev->data;
+
+    if (!data->settings_init) {
+
+        data->status = true;
+        k_work_schedule(&ext_power_save_work, K_NO_WAIT);
+
+        ext_power_enable(dev);
+    }
+
+    return 0;
+}
+
+SETTINGS_STATIC_HANDLER_DEFINE(ext_power, "ext_power/state", NULL, ext_power_settings_set,
+                               ext_power_settings_commit, NULL);
+
 #endif
 
 static int ext_power_generic_init(const struct device *dev) {
-    struct ext_power_generic_data *data = dev->data;
     const struct ext_power_generic_config *config = dev->config;
 
     if (gpio_pin_configure_dt(&config->control, GPIO_OUTPUT_INACTIVE)) {
@@ -135,25 +150,7 @@ static int ext_power_generic_init(const struct device *dev) {
     }
 
 #if IS_ENABLED(CONFIG_SETTINGS)
-    settings_subsys_init();
-
-    int err = settings_register(&ext_power_conf);
-    if (err) {
-        LOG_ERR("Failed to register the ext_power settings handler (err %d)", err);
-        return err;
-    }
-
     k_work_init_delayable(&ext_power_save_work, ext_power_save_state_work);
-
-    // Set default value (on) if settings isn't set
-    settings_load_subtree("ext_power");
-    if (!data->settings_init) {
-
-        data->status = true;
-        k_work_schedule(&ext_power_save_work, K_NO_WAIT);
-
-        ext_power_enable(dev);
-    }
 #else
     // Default to the ext_power being open when no settings
     ext_power_enable(dev);

app/src/main.c

@@ -24,6 +24,11 @@ int main(void) {
         return -ENOTSUP;
     }
 
+#if IS_ENABLED(CONFIG_SETTINGS)
+    settings_subsys_init();
+    settings_load();
+#endif
+
 #ifdef CONFIG_ZMK_DISPLAY
     zmk_display_init();
 #endif /* CONFIG_ZMK_DISPLAY */

app/src/rgb_underglow.c

@@ -230,7 +230,7 @@ static int rgb_settings_set(const char *name, size_t len, settings_read_cb read_
     return -ENOENT;
 }
 
-struct settings_handler rgb_conf = {.name = "rgb/underglow", .h_set = rgb_settings_set};
+SETTINGS_STATIC_HANDLER_DEFINE(rgb_underglow, "rgb/underglow", NULL, rgb_settings_set, NULL, NULL);
 
 static void zmk_rgb_underglow_save_state_work(struct k_work *_work) {
     settings_save_one("rgb/underglow/state", &state, sizeof(state));
@@ -262,17 +262,7 @@ static int zmk_rgb_underglow_init(void) {
     };
 
 #if IS_ENABLED(CONFIG_SETTINGS)
-    settings_subsys_init();
-
-    int err = settings_register(&rgb_conf);
-    if (err) {
-        LOG_ERR("Failed to register the ext_power settings handler (err %d)", err);
-        return err;
-    }
-
     k_work_init_delayable(&underglow_save_work, zmk_rgb_underglow_save_state_work);
-
-    settings_load_subtree("rgb/underglow");
 #endif
 
 #if IS_ENABLED(CONFIG_ZMK_RGB_UNDERGLOW_AUTO_OFF_USB)

app/src/split/bluetooth/central.c

@@ -12,6 +12,7 @@
 #include <zephyr/bluetooth/uuid.h>
 #include <zephyr/bluetooth/gatt.h>
 #include <zephyr/bluetooth/hci.h>
+#include <zephyr/settings/settings.h>
 #include <zephyr/sys/byteorder.h>
 
 #include <zephyr/logging/log.h>
@@ -865,13 +866,34 @@ int zmk_split_bt_update_hid_indicator(zmk_hid_indicators_t indicators) {
 
 #endif // IS_ENABLED(CONFIG_ZMK_SPLIT_PERIPHERAL_HID_INDICATORS)
 
+static int finish_init() {
+    return IS_ENABLED(CONFIG_ZMK_BLE_CLEAR_BONDS_ON_START) ? 0 : start_scanning();
+}
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+
+static int central_ble_handle_set(const char *name, size_t len, settings_read_cb read_cb,
+                                  void *cb_arg) {
+    return 0;
+}
+
+static struct settings_handler ble_central_settings_handler = {
+    .name = "ble_central", .h_set = central_ble_handle_set, .h_commit = finish_init};
+
+#endif // IS_ENABLED(CONFIG_SETTINGS)
+
 static int zmk_split_bt_central_init(void) {
     k_work_queue_start(&split_central_split_run_q, split_central_split_run_q_stack,
                        K_THREAD_STACK_SIZEOF(split_central_split_run_q_stack),
                        CONFIG_ZMK_BLE_THREAD_PRIORITY, NULL);
     bt_conn_cb_register(&conn_callbacks);
 
-    return IS_ENABLED(CONFIG_ZMK_BLE_CLEAR_BONDS_ON_START) ? 0 : start_scanning();
+#if IS_ENABLED(CONFIG_SETTINGS)
+    settings_register(&ble_central_settings_handler);
+    return 0;
+#else
+    return finish_init();
+#endif // IS_ENABLED(CONFIG_SETTINGS)
 }
 
 SYS_INIT(zmk_split_bt_central_init, APPLICATION, CONFIG_ZMK_BLE_INIT_PRIORITY);

app/src/split/bluetooth/peripheral.c

@@ -146,21 +146,7 @@ bool zmk_split_bt_peripheral_is_connected(void) { return is_connected; }
 
 bool zmk_split_bt_peripheral_is_bonded(void) { return is_bonded; }
 
-static int zmk_peripheral_ble_init(void) {
-    int err = bt_enable(NULL);
-
-    if (err) {
-        LOG_ERR("BLUETOOTH FAILED (%d)", err);
-        return err;
-    }
-
-#if IS_ENABLED(CONFIG_SETTINGS)
-    settings_subsys_init();
-
-    settings_load_subtree("ble");
-    settings_load_subtree("bt");
-#endif
-
+static int zmk_peripheral_ble_complete_startup(void) {
 #if IS_ENABLED(CONFIG_ZMK_BLE_CLEAR_BONDS_ON_START)
     LOG_WRN("Clearing all existing BLE bond information from the keyboard");
 
@@ -176,4 +162,35 @@ static int zmk_peripheral_ble_init(void) {
     return 0;
 }
 
+#if IS_ENABLED(CONFIG_SETTINGS)
+
+static int peripheral_ble_handle_set(const char *name, size_t len, settings_read_cb read_cb,
+                                     void *cb_arg) {
+    return 0;
+}
+
+static struct settings_handler ble_peripheral_settings_handler = {
+    .name = "ble_peripheral",
+    .h_set = peripheral_ble_handle_set,
+    .h_commit = zmk_peripheral_ble_complete_startup};
+
+#endif // IS_ENABLED(CONFIG_SETTINGS)
+
+static int zmk_peripheral_ble_init(void) {
+    int err = bt_enable(NULL);
+
+    if (err) {
+        LOG_ERR("BLUETOOTH FAILED (%d)", err);
+        return err;
+    }
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+    settings_register(&ble_peripheral_settings_handler);
+#else
+    zmk_peripheral_ble_complete_startup();
+#endif
+
+    return 0;
+}
+
 SYS_INIT(zmk_peripheral_ble_init, APPLICATION, CONFIG_ZMK_BLE_INIT_PRIORITY);