feat(bluetooth): Proper bond management, identity support for non-splits

* Add `bt` behavior that can be used to perform certain actions,
  such as next/prev identity, reset identity, etc.
  NOTE: Multiple identities is only supported for non-split shields,
  due to missing Zephyr identity functionality for dual
  central/peripheral devices.
* Proper bond reset tied to action, that honors peripheral bonds,
  so folks can reset and pair to other hosts, without breaking
  bonds between splt halves.

app/CMakeLists.txt

@@ -41,8 +41,11 @@ target_sources(app PRIVATE src/behaviors/behavior_toggle_layer.c)
 target_sources(app PRIVATE src/behaviors/behavior_transparent.c)
 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/keymap.c)
+if(NOT CONFIG_ZMK_BLE_SPLIT_PERIPHERAL)
+  target_sources(app PRIVATE src/keymap.c)
+endif()
 target_sources_ifdef(CONFIG_ZMK_RGB_UNDERGLOW app PRIVATE src/behaviors/behavior_rgb_underglow.c)
+target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/behaviors/behavior_bt.c)
 target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/ble.c)
 target_sources_ifdef(CONFIG_ZMK_BLE app PRIVATE src/ble_unpair_combo.c)
 target_sources_ifdef(CONFIG_ZMK_SPLIT_BLE_ROLE_PERIPHERAL app PRIVATE src/split_listener.c)

app/Kconfig

@@ -40,8 +40,6 @@ menuconfig ZMK_BLE
 	select BT_PERIPHERAL
 	select BT_GATT_DIS
 	select BT_GATT_BAS
-	select SETTINGS
-	# select BT_SETTINGS
 
 if ZMK_BLE
 
@@ -49,6 +47,12 @@ config ZMK_BLE_INIT_PRIORITY
 	int "Init Priority"
 	default 50
 
+config SETTINGS
+	default y
+
+config BT_SETTINGS
+	default y
+	
 config SYSTEM_WORKQUEUE_STACK_SIZE
 	default 2048
 
@@ -103,8 +107,11 @@ config ZMK_SPLIT_BLE_ROLE_CENTRAL
 
 if ZMK_SPLIT_BLE_ROLE_CENTRAL
 
+config BT_MAX_PAIRED
+	default 2
+
 config BT_MAX_CONN
-	default 5
+	default 2
 
 config BT_MAX_PAIRED
 	# Bump this everywhere once we support switching active connections!
@@ -120,15 +127,18 @@ if ZMK_SPLIT_BLE_ROLE_PERIPHERAL
 config ZMK_USB
 	default n
 
+config BT_MAX_PAIRED
+	default 1
 
 config BT_MAX_CONN
-	default 5
+	default 2
 
 config BT_GAP_AUTO_UPDATE_CONN_PARAMS
 	default n
 
 endif
 
+
 endchoice
 
 endif
@@ -138,6 +148,17 @@ endif
 endmenu
 
 
+if ZMK_BLE && !ZMK_SPLIT_BLE
+
+config BT_ID_MAX
+	default 5
+
+# Used to update the name to include the identity used
+config BT_DEVICE_NAME_DYNAMIC
+	default y
+
+endif
+
 config ZMK_KSCAN_MOCK_DRIVER
 	bool "Enable mock kscan driver to simulate key presses"
 	default n

app/dts/behaviors.dtsi

@@ -8,3 +8,4 @@
 #include <behaviors/reset.dtsi>
 #include <behaviors/sensor_rotate_key_press.dtsi>
 #include <behaviors/rgb_underglow.dtsi>
+#include <behaviors/bluetooth.dtsi>

app/dts/behaviors/bluetooth.dtsi

@@ -0,0 +1,9 @@
+/ {
+	behaviors {
+		bt: behavior_bluetooth {
+			compatible = "zmk,behavior-bluetooth";
+			label = "BLUETOOTH";
+			#binding-cells = <2>;
+		};
+	};
+};

app/dts/bindings/behaviors/zmk,behavior-bluetooth.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2020, Peter Johanson
+# SPDX-License-Identifier: MIT
+
+description: Bluetooth Behavior
+
+compatible: "zmk,behavior-bluetooth"
+
+include: two_param.yaml

app/include/dt-bindings/zmk/bt.h

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2020 Peter Johanson <peter@peterjohanson.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define BT_RST_CMD       0
+#define BT_IDENT_NEXT_CMD 1
+#define BT_IDENT_PREV_CMD 2
+#define BT_IDENT_SEL_CMD  3
+#define BT_IDENT_CLR_CMD  4
+
+#define BT_RST       BT_RST_CMD 0
+#define BT_IDENT_NEXT BT_IDENT_NEXT_CMD 0
+#define BT_IDENT_PREV BT_IDENT_PREV_CMD 0
+#define BT_IDENT_SEL  BT_IDENT_SEL_CMD
+#define BT_IDENT_CLR  BT_IDENT_CLR_CMD 0

app/include/zmk/ble.h

@@ -6,7 +6,20 @@
 
 #pragma once
 
+#include <bluetooth/addr.h>
 #include <zmk/keys.h>
 
+int zmk_ble_adv_pause();
+int zmk_ble_adv_resume();
+
+int zmk_ble_identity_clear();
+int zmk_ble_identity_next();
+int zmk_ble_identity_prev();
+int zmk_ble_identity_select(u8_t index);
+
 int zmk_ble_unpair_all();
 bool zmk_ble_handle_key_user(struct zmk_key_event *key_event);
+
+#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
+void zmk_ble_set_peripheral_addr(bt_addr_le_t *addr);
+#endif /* IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL) */

app/src/behaviors/behavior_bt.c

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2020 Peter Johanson <peter@peterjohanson.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_bluetooth
+
+#include <device.h>
+#include <drivers/behavior.h>
+
+#include <dt-bindings/zmk/bt.h>
+
+#include <bluetooth/conn.h>
+
+#include <logging/log.h>
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#include <zmk/ble.h>
+
+static int on_keymap_binding_pressed(struct device *dev, u32_t position, u32_t command, u32_t arg)
+{
+    switch (command)
+    {
+    case BT_RST_CMD:
+        return zmk_ble_unpair_all();
+    case BT_IDENT_CLR_CMD:
+        return zmk_ble_identity_clear();
+#if CONFIG_BT_ID_MAX != 1
+    case BT_IDENT_NEXT_CMD:
+        return zmk_ble_identity_next();
+    case BT_IDENT_PREV_CMD:
+        return zmk_ble_identity_prev();
+    case BT_IDENT_SEL_CMD:
+        return zmk_ble_identity_select(arg);
+#endif /* BT_ID_MAX != 1 */
+    }
+
+    return -ENOTSUP;
+}
+
+static int behavior_bt_init(struct device *dev)
+{
+    return 0;
+};
+
+static int on_keymap_binding_released(struct device *dev, u32_t position, u32_t command, u32_t arg)
+{
+    return 0;
+}
+
+static const struct behavior_driver_api behavior_bt_driver_api = {
+    .binding_pressed = on_keymap_binding_pressed,
+    .binding_released = on_keymap_binding_released,
+};
+
+DEVICE_AND_API_INIT(behavior_bt, DT_INST_LABEL(0),
+                    behavior_bt_init,
+                    NULL,
+                    NULL,
+                    APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,
+                    &behavior_bt_driver_api);

app/src/ble.c

@@ -8,6 +8,8 @@
 #include <init.h>
 
 #include <math.h>
+#include <stdlib.h>
+#include <stdio.h>
 
 #include <settings/settings.h>
 #include <bluetooth/bluetooth.h>
@@ -15,6 +17,13 @@
 #include <bluetooth/hci.h>
 #include <bluetooth/uuid.h>
 #include <bluetooth/gatt.h>
+#include <bluetooth/hci_err.h>
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+
+#include <settings/settings.h>
+
+#endif
 
 
 #include <logging/log.h>
@@ -28,15 +37,248 @@ static struct bt_conn *auth_passkey_entry_conn;
 static u8_t passkey_entries[6] = {0, 0, 0, 0, 0, 0};
 static u8_t passkey_digit = 0;
 
-#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_PERIPHERAL)
+#define ZMK_BT_LE_ADV_PARAM_INIT(_id, _options, _int_min, _int_max, _peer) \
-#define ZMK_ADV_PARAMS BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE | \
+{ \
-                                        BT_LE_ADV_OPT_USE_NAME | \
+        .id = _id, \
-                                        BT_LE_ADV_OPT_ONE_TIME, \
+        .sid = 0, \
+        .secondary_max_skip = 0, \
+        .options = (_options), \
+        .interval_min = (_int_min), \
+        .interval_max = (_int_max), \
+        .peer = (_peer), \
+}
+
+#define ZMK_BT_LE_ADV_PARAM(_id, _options, _int_min, _int_max, _peer) \
+        ((struct bt_le_adv_param[]) { \
+                ZMK_BT_LE_ADV_PARAM_INIT(_id, _options, _int_min, _int_max, _peer) \
+        })
+
+#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
+#define ZMK_ADV_PARAMS(_id) ZMK_BT_LE_ADV_PARAM(_id, \
+                                        BT_LE_ADV_OPT_CONNECTABLE | \
+                                        BT_LE_ADV_OPT_ONE_TIME | \
+                                        BT_LE_ADV_OPT_USE_NAME, \
                                         BT_GAP_ADV_FAST_INT_MIN_2, \
                                         BT_GAP_ADV_FAST_INT_MAX_2, NULL)
 #else
-#define ZMK_ADV_PARAMS BT_LE_ADV_CONN_NAME
+#define ZMK_ADV_PARAMS(_id) ZMK_BT_LE_ADV_PARAM(_id, \
+                                        BT_LE_ADV_OPT_CONNECTABLE | \
+                                        BT_LE_ADV_OPT_USE_NAME, \
+                                        BT_GAP_ADV_FAST_INT_MIN_2, \
+                                        BT_GAP_ADV_FAST_INT_MAX_2, NULL)
+#endif
+
+static const struct bt_data zmk_ble_ad[] = {
+    BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
+    BT_DATA_BYTES(BT_DATA_UUID16_SOME,
+#if !IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_PERIPHERAL)
+                  0x12, 0x18,  /* HID Service */
+#endif
+                  0x0f, 0x18 /* Battery Service */
+    ),
+#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_PERIPHERAL)
+    BT_DATA_BYTES(BT_DATA_UUID128_ALL,
+                ZMK_SPLIT_BT_SERVICE_UUID)
+#endif
+};
+
+#define IDENTITY_COUNT CONFIG_BT_ID_MAX
+
+#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
+
+static bt_addr_le_t peripheral_addr;
+
+#endif /* IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL) */
+
+
+static u8_t active_identity = 0;
+
+int zmk_ble_adv_pause()
+{
+    int err = bt_le_adv_stop();
+    if (err) {
+        LOG_ERR("Failed to stop advertising (err %d)", err);
+        return err;
+    }
+
+    return 0;
+};
+
+int zmk_ble_adv_resume()
+{
+    struct bt_le_adv_param *adv_params = ZMK_ADV_PARAMS(active_identity);
+
+    LOG_DBG("");
+    int err = bt_le_adv_start(adv_params, zmk_ble_ad, ARRAY_SIZE(zmk_ble_ad), NULL, 0);
+    if (err)
+    {
+        LOG_ERR("Advertising failed to start (err %d)", err);
+        return err;
+    }
+
+    return 0;
+};
+
+static void disconnect_host_connection(struct bt_conn *conn, void *arg)
+{
+    struct bt_conn_info info;
+    bt_conn_get_info(conn, &info);
+
+    if (info.role != BT_CONN_ROLE_SLAVE) {
+        return;
+    }
+
+    bt_conn_disconnect(conn, BT_HCI_ERR_LOCALHOST_TERM_CONN);
+};
+
+static int activate_profile(u8_t index)
+{
+    int err;
+    
+    if (index >= IDENTITY_COUNT) {
+        return -EINVAL;
+    }
+
+    if (active_identity != index) {
+        LOG_DBG("Persisting new active identity");
+        active_identity = index;
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+        err = settings_save_one("ble/active_identity", &active_identity, sizeof(u8_t));
+        if (err) {
+            LOG_WRN("Failed to persist active_identity (err %d)", err);
+        }
+#endif
+
+#if IS_ENABLED(CONFIG_BT_DEVICE_NAME_DYNAMIC)
+        char name[CONFIG_BT_DEVICE_NAME_MAX];
+        snprintf(name, sizeof(name), "%s (Profile %d)", CONFIG_ZMK_KEYBOARD_NAME, active_identity + 1);
+        bt_set_name(name);
+#endif /* IS_ENABLED(CONFIG_BT_DEVICE_NAME_DYNAMIC) */
+    }
+
+    return zmk_ble_adv_resume();
+};
+
+static int deactivate_profile(u8_t index)
+{
+    int err = zmk_ble_adv_pause();
+    if (err) {
+        LOG_WRN("Failed to pause advertising %d", err);
+    }
+
+    bt_conn_foreach(BT_CONN_TYPE_ALL, disconnect_host_connection, NULL);
+
+    return 0;
+};
+
+int zmk_ble_identity_select(u8_t index)
+{
+    LOG_DBG("index %d", index);
+    if (index >= IDENTITY_COUNT) {
+        return -EINVAL;
+    }
+
+    int err = deactivate_profile(active_identity);
+    if (err) {
+        LOG_WRN("Failed to deactivate profile");
+        return err;
+    }
+
+    return activate_profile(index);
+};
+
+static void unpair_non_peripheral_bonds(const struct bt_bond_info *info, void *user_data) {
+    char addr[BT_ADDR_LE_STR_LEN];
+    bt_addr_le_to_str(&info->addr, addr, sizeof(addr));
+
+#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
+    if (!bt_addr_le_cmp(&info->addr, &peripheral_addr)) {
+        LOG_DBG("Skipping unpairing peripheral %s", log_strdup(addr));
+        return;
+    }
+#endif /* IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL) */
+
+    LOG_DBG("Unpairing %s", log_strdup(addr));
+    bt_unpair(active_identity, &info->addr);
+}
+
+int zmk_ble_identity_clear()
+{
+    LOG_DBG("");
+    int err = deactivate_profile(active_identity);
+    if (err) {
+        return err;
+    }
+
+    bt_foreach_bond(active_identity, unpair_non_peripheral_bonds, NULL);
+
+    return activate_profile(active_identity);
+};
+
+int zmk_ble_identity_next()
+{
+    LOG_DBG("active_identity %d IDENTITY_COUNT %d", active_identity, IDENTITY_COUNT);
+    return zmk_ble_identity_select((active_identity + 1) % IDENTITY_COUNT);
+}
+
+int zmk_ble_identity_prev()
+{
+    LOG_DBG("");
+    return zmk_ble_identity_select((active_identity + IDENTITY_COUNT - 1) % IDENTITY_COUNT);
+}
+
+#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
+
+void zmk_ble_set_peripheral_addr(bt_addr_le_t *addr)
+{
+    memcpy(&peripheral_addr, addr, sizeof(bt_addr_le_t));
+    settings_save_one("ble/peripheral_address", addr, sizeof(bt_addr_le_t));
+}
+
+#endif /* IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL) */
+
+#if IS_ENABLED(CONFIG_SETTINGS)
+
+static int ble_profiles_handle_set(const char *name, size_t len, settings_read_cb read_cb, void *cb_arg)
+{
+    const char *next;
+
+    LOG_DBG("Setting BLE value %s", log_strdup(name));
+
+    if (settings_name_steq(name, "active_identity", &next) && !next) {
+        if (len != sizeof(active_identity)) {
+            return -EINVAL;
+        }
+
+        int err = read_cb(cb_arg, &active_identity, sizeof(active_identity));
+        if (err <= 0) {
+            LOG_ERR("Failed to handle profile from settings (err %d)", err);
+            return err;
+        }
+        LOG_DBG("Loaded active identity %d", active_identity);
+#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
+    } else if (settings_name_steq(name, "peripheral_address", &next) && !next) {
+        if (len != sizeof(bt_addr_le_t)) {
+            return -EINVAL;
+        }
+
+        int err = read_cb(cb_arg, &peripheral_addr, sizeof(bt_addr_le_t));
+        if (err <= 0) {
+            LOG_ERR("Failed to handle peripheral address from settings (err %d)", err);
+            return err;
+        }
 #endif
+    }
+
+    return 0;
+};
+
+struct settings_handler profiles_handler = {
+    .name = "ble",
+    .h_set = ble_profiles_handle_set
+};
+#endif /* IS_ENABLED(CONFIG_SETTINGS) */
 
 static void connected(struct bt_conn *conn, u8_t err)
 {
@@ -71,6 +313,12 @@ static void disconnected(struct bt_conn *conn, u8_t reason)
     bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
     LOG_DBG("Disconnected from %s (reason 0x%02x)", log_strdup(addr), reason);
+
+#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL)
+    if (bt_addr_le_cmp(&peripheral_addr, BT_ADDR_LE_ANY) && bt_addr_le_cmp(&peripheral_addr, bt_conn_get_dst(conn))) {
+        zmk_ble_adv_resume();
+    }
+#endif
 }
 
 static void security_changed(struct bt_conn *conn, bt_security_t level,
@@ -146,19 +394,6 @@ static struct bt_conn_auth_cb zmk_ble_auth_cb_display = {
     .cancel = auth_cancel,
 };
 
-static const struct bt_data zmk_ble_ad[] = {
-    BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
-    BT_DATA_BYTES(BT_DATA_UUID16_SOME,
-#if !IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_PERIPHERAL)
-                  0x12, 0x18,  /* HID Service */
-#endif
-                  0x0f, 0x18 /* Battery Service */
-    ),
-#if IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_PERIPHERAL)
-    BT_DATA_BYTES(BT_DATA_UUID128_ALL,
-                  ZMK_SPLIT_BT_SERVICE_UUID)
-#endif
-};
 
 static void zmk_ble_ready(int err)
 {
@@ -169,17 +404,42 @@ static void zmk_ble_ready(int err)
         return;
     }
 
-    err = bt_le_adv_start(ZMK_ADV_PARAMS, zmk_ble_ad, ARRAY_SIZE(zmk_ble_ad), NULL, 0);
+    zmk_ble_identity_select(active_identity);
-    if (err)
-    {
-        LOG_ERR("Advertising failed to start (err %d)", err);
-        return;
-    }
 }
 
+#if CONFIG_BT_ID_MAX != 1
+static int initialize_identities()
+{
+    bt_addr_le_t addrs[CONFIG_BT_ID_MAX];
+    size_t count = CONFIG_BT_ID_MAX;
+
+    LOG_DBG("");
+    bt_id_get(addrs, &count);
+
+    for (int i = 0; i < count; i++) {
+        char addr[BT_ADDR_LE_STR_LEN];
+        bt_addr_le_to_str(&addrs[i], addr, sizeof(addr));
+        LOG_DBG("Existing identity %s", log_strdup(addr));
+    }
+
+    for (int i = count; i < CONFIG_BT_ID_MAX; i++) {
+        LOG_DBG("Initializing identity %d", i);
+        int id = bt_id_create(NULL, NULL);
+        if (id < 0) {
+            LOG_ERR("Failed to create new identity with id %d", i);
+            return id;
+        }
+    }
+
+    return 0;
+};
+#endif /* CONFIG_BT_ID_MAX != 1 */
+
 static int zmk_ble_init(struct device *_arg)
 {
-    int err = bt_enable(NULL);
+    int err;
+
+    err = bt_enable(NULL);
 
     if (err)
     {
@@ -187,11 +447,23 @@ static int zmk_ble_init(struct device *_arg)
         return err;
     }
 
-    if (IS_ENABLED(CONFIG_BT_SETTINGS))
+#if IS_ENABLED(CONFIG_SETTINGS)
-    {
+    settings_subsys_init();
-        settings_load();
+
+    err = settings_register(&profiles_handler);
+    if (err) {
+        LOG_ERR("Failed to setup the profile settings handler (err %d)", err);
+        return err;
     }
 
+    settings_load();
+
+#endif
+
+#if CONFIG_BT_ID_MAX != 1
+    initialize_identities();
+#endif /* CONFIG_BT_ID_MAX != 1 */
+
     bt_conn_cb_register(&conn_callbacks);
     bt_conn_auth_cb_register(&zmk_ble_auth_cb_display);
 
@@ -203,7 +475,12 @@ static int zmk_ble_init(struct device *_arg)
 int zmk_ble_unpair_all()
 {
     LOG_DBG("");
-    return bt_unpair(BT_ID_DEFAULT, NULL);
+    int err = bt_unpair(BT_ID_DEFAULT, NULL);
+    if (err) {
+        LOG_ERR("Failed to unpair devices (err %d)", err);
+    }
+
+    return err;
 };
 
 bool zmk_ble_handle_key_user(struct zmk_key_event *key_event)

app/src/split/bluetooth/central.c

@@ -10,12 +10,14 @@
 #include <bluetooth/conn.h>
 #include <bluetooth/uuid.h>
 #include <bluetooth/gatt.h>
+#include <bluetooth/hci.h>
 #include <sys/byteorder.h>
 
 #include <logging/log.h>
 
 LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
+#include <zmk/ble.h>
 #include <zmk/split/bluetooth/uuid.h>
 #include <zmk/event-manager.h>
 #include <zmk/events/position-state-changed.h>
@@ -71,6 +73,18 @@ static u8_t split_central_notify_func(struct bt_conn *conn,
 	return BT_GATT_ITER_CONTINUE;
 }
 
+static int split_central_subscribe(struct bt_conn *conn)
+{
+	int err = bt_gatt_subscribe(conn, &subscribe_params);
+	if (err && err != -EALREADY) {
+		LOG_ERR("Subscribe failed (err %d)", err);
+	} else {
+		LOG_DBG("[SUBSCRIBED]");
+	}
+
+	return 0;
+}
+
 static u8_t split_central_discovery_func(struct bt_conn *conn,
 			     const struct bt_gatt_attr *attr,
 			     struct bt_gatt_discover_params *params)
@@ -112,12 +126,7 @@ static u8_t split_central_discovery_func(struct bt_conn *conn,
 		subscribe_params.value = BT_GATT_CCC_NOTIFY;
 		subscribe_params.ccc_handle = attr->handle;
 
-		err = bt_gatt_subscribe(conn, &subscribe_params);
+		split_central_subscribe(conn);
-		if (err && err != -EALREADY) {
-			LOG_ERR("Subscribe failed (err %d)", err);
-		} else {
-			LOG_DBG("[SUBSCRIBED]");
-		}
 
 		return BT_GATT_ITER_STOP;
 	}
@@ -137,6 +146,9 @@ static void split_central_process_connection(struct bt_conn *conn) {
 	}
 
 	if (conn == default_conn) {
+		if (subscribe_params.value) {
+			split_central_subscribe(conn);
+		} else {
 			discover_params.uuid = &uuid.uuid;
 			discover_params.func = split_central_discovery_func;
 			discover_params.start_handle = 0x0001;
@@ -149,6 +161,7 @@ static void split_central_process_connection(struct bt_conn *conn) {
 				return;
 			}
 		}
+	}
 
 	struct bt_conn_info info;
 
@@ -194,6 +207,8 @@ static bool split_central_eir_found(struct bt_data *data, void *user_data)
 
 			LOG_DBG("Found the split service");
 
+			zmk_ble_set_peripheral_addr(addr);
+
 			err = bt_le_scan_stop();
 			if (err) {
 				LOG_ERR("Stop LE scan failed (err %d)", err);
@@ -206,10 +221,11 @@ static bool split_central_eir_found(struct bt_data *data, void *user_data)
 				split_central_process_connection(default_conn);
 			} else {
 				param = BT_LE_CONN_PARAM(0x0006, 0x0006, 30, 400);
+
 				err = bt_conn_le_create(addr, BT_CONN_LE_CREATE_CONN,
 							param, &default_conn);
 				if (err) {
-					LOG_ERR("Create conn failed (err %d)", err);
+					LOG_ERR("Create conn failed (err %d) (create conn? 0x%04x)", err, BT_HCI_OP_LE_CREATE_CONN);
 					start_scan();
 				}
 
@@ -263,6 +279,7 @@ static void split_central_connected(struct bt_conn *conn, u8_t conn_err)
 
 	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
 
+
 	if (conn_err) {
 		LOG_ERR("Failed to connect to %s (%u)", addr, conn_err);
 

docs/docs/behavior/bluetooth.md

@@ -0,0 +1,82 @@
+---
+title: Bluetooth Behavior
+sidebar_label: Bluetooth
+---
+
+## Summary
+
+The bluetooth behavior allows management of various settings and states related to the bluetooth connection(s)
+between the keyboard and the host.
+
+## Bluetooth Command Defines
+
+Bluetooth command defines are provided through the [`dt-bindings/zmk/bt.h`](https://github.com/zmkfirmware/zmk/blob/main/app/include/dt-bindings/zmk/bt.h) header,
+which is added at the top of the keymap file:
+
+```
+#include <dt-bindings/zmk/bt.h>
+```
+
+This will allow you to reference the actions defined in this header such as `BT_IDENT_CLR_CMD`.
+
+Here is a table describing the command for each define:
+
+| Define              | Action                                                |
+| ------------------- | ----------------------------------------------------- |
+| `BT_IDENT_CLR_CMD`  | Clear paired keyboards (for the current identity)[^1] |
+| `BT_IDENT_NEXT_CMD` | Switch to the next identity[^1]                       |
+| `BT_IDENT_PREV_CMD` | Switch to the previous identity                       |
+| `BT_IDENT_SEL_CMD`  | Switch to a specific numbered identity                |
+| `BT_RST_CMD`        | Hard reset of all bluetooth bonds                     |
+
+Because the `BT_IDENT_SEL_CMD` command takes an additional parameter, the numeric index of the identity to select, _all_ the commands for the bluetooth behavior must take that additional parameter, and ignore the value. To make this easier,
+there are alias defines that add those default parameters for you:
+
+| Define          | Action                                                                                  |
+| --------------- | --------------------------------------------------------------------------------------- |
+| `BT_IDENT_CLR`  | Alias for `BT_IDENT_CLR_CMD 0` to clear paired keyboards (for the current identity)[^1] |
+| `BT_IDENT_NEXT` | Alias for `BT_IDENT_NEXT_CMD 0` to switch to the next identity[^1]                      |
+| `BT_IDENT_PREV` | Alias for `BT_IDENT_PREV_CMD 0` to switch to the previous identity                      |
+| `BT_IDENT_SEL`  | Alias for `BT_IDENT_SEL_CMD` to switch to a specific numbered identity                  |
+| `BT_RST`        | Alias for `BT_RST_CMD 0` to reset all bonds[^2]                                         |
+
+[^1]: Multiple keyboard identities/profiles is only support on non-split keyboards as of this time.
+[^2]: This may interrupt pairing between both halves of a split keyboard. For split keyboards, it is preferred to use the [/docs/bond-reset] combo to clear bonds on both devices
+
+## Bluetooth Behavior
+
+The bluetooth behavior completes an bluetooth action given on press.
+
+### Behavior Binding
+
+- Reference: `&bt`
+- Parameter #1: The bluetooth command define, e.g. `BT_IDENT_CLR_CMD` or `BT_RST_CMD`
+- Parameter #2: The parameter for the command, when used to identify an identity/profile to select, e.g. `0`
+
+### Examples
+
+1. Behavior to clear the paired host:
+
+   ```
+   &bt BT_IDENT_CLR
+   ```
+
+1. Behavior to hard reset all bonded devices[^2]:
+
+   ```
+   &bt BT_IDENT_CLR
+   ```
+
+Examples for non-split keyboards with multiple identities:
+
+1. Behavior to switch to the next identity:
+
+   ```
+   &bt BT_IDENT_NEXT
+   ```
+
+1. Behavior to switch to the specific numbered identity:
+
+   ```
+   &bt BT_IDENT_SEL 1
+   ```

docs/sidebars.js

@@ -22,6 +22,7 @@ module.exports = {
       "behavior/hold-tap",
       "behavior/mod-tap",
       "behavior/reset",
+      "behavior/bluetooth",
       "behavior/lighting",
     ],
     Development: [