refactor(splits): Use index for event source.

* Track peripherals by indexes slot, with all appropiate peripheral
  state stored in the slot.
* Event sources tracked by peripheral slot index.

8 files changed, 253 insertions, 104 deletions

diff --git a/app/include/zmk/ble.h b/app/include/zmk/ble.h
index 0bdbab3..f813ddc 100644
--- a/app/include/zmk/ble.h
+++ b/app/include/zmk/ble.h
@@ -9,6 +9,17 @@
 #include <zmk/keys.h>
 #include <zmk/ble/profile.h>
 
+#define ZMK_BLE_IS_CENTRAL                                                                         \
+    (IS_ENABLED(CONFIG_ZMK_SPLIT) && IS_ENABLED(CONFIG_ZMK_BLE) &&                                 \
+     IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL))
+
+#if ZMK_BLE_IS_CENTRAL
+#define ZMK_BLE_PROFILE_COUNT (CONFIG_BT_MAX_PAIRED - 1)
+#define ZMK_BLE_SPLIT_PERIPHERAL_COUNT 1
+#else
+#define ZMK_BLE_PROFILE_COUNT CONFIG_BT_MAX_PAIRED
+#endif
+
 int zmk_ble_clear_bonds();
 int zmk_ble_prof_next();
 int zmk_ble_prof_prev();
diff --git a/app/include/zmk/events/position_state_changed.h b/app/include/zmk/events/position_state_changed.h
index 59619db..7685fe0 100644
--- a/app/include/zmk/events/position_state_changed.h
+++ b/app/include/zmk/events/position_state_changed.h
@@ -8,16 +8,9 @@
 
 #include <zephyr.h>
 #include <zmk/event_manager.h>
-#include <bluetooth/addr.h>
-
-#if IS_ENABLED(CONFIG_ZMK_BLE)
-typedef const bt_addr_le_t *zmk_position_state_changed_source_t;
-#else
-typedef void *zmk_position_state_changed_source_t;
-#endif
 
 struct zmk_position_state_changed {
-    zmk_position_state_changed_source_t source;
+    uint8_t source;
     uint32_t position;
     bool state;
     int64_t timestamp;
diff --git a/app/include/zmk/keymap.h b/app/include/zmk/keymap.h
index 0771542..1195b94 100644
--- a/app/include/zmk/keymap.h
+++ b/app/include/zmk/keymap.h
@@ -20,8 +20,8 @@ int zmk_keymap_layer_toggle(uint8_t layer);
 int zmk_keymap_layer_to(uint8_t layer);
 const char *zmk_keymap_layer_label(uint8_t layer);
 
-int zmk_keymap_position_state_changed(zmk_position_state_changed_source_t source, uint32_t position,
-                                      bool pressed, int64_t timestamp);
+int zmk_keymap_position_state_changed(uint8_t source, uint32_t position, bool pressed,
+                                      int64_t timestamp);
 
 #define ZMK_KEYMAP_EXTRACT_BINDING(idx, drv_inst)                                                  \
     {                                                                                              \
diff --git a/app/include/zmk/split/bluetooth/central.h b/app/include/zmk/split/bluetooth/central.h
index ab46a8f..0724086 100644
--- a/app/include/zmk/split/bluetooth/central.h
+++ b/app/include/zmk/split/bluetooth/central.h
@@ -4,5 +4,5 @@
 #include <bluetooth/addr.h>
 #include <zmk/behavior.h>
 
-int zmk_split_bt_invoke_behavior(const bt_addr_le_t *source, struct zmk_behavior_binding *binding,
+int zmk_split_bt_invoke_behavior(uint8_t source, struct zmk_behavior_binding *binding,
                                  struct zmk_behavior_binding_event event, bool state);
\ No newline at end of file
diff --git a/app/src/ble.c b/app/src/ble.c
index 6806112..afc2e47 100644
--- a/app/src/ble.c
+++ b/app/src/ble.c
@@ -72,7 +72,7 @@ enum advertising_type {
     BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE | BT_LE_ADV_OPT_ONE_TIME, BT_GAP_ADV_FAST_INT_MIN_2, \
                     BT_GAP_ADV_FAST_INT_MAX_2, NULL)
 
-static struct zmk_ble_profile profiles[PROFILE_COUNT];
+static struct zmk_ble_profile profiles[ZMK_BLE_PROFILE_COUNT];
 static uint8_t active_profile;
 
 #define DEVICE_NAME CONFIG_BT_DEVICE_NAME
@@ -260,7 +260,7 @@ static int ble_save_profile() {
 }
 
 int zmk_ble_prof_select(uint8_t index) {
-    if (index >= PROFILE_COUNT) {
+    if (index >= ZMK_BLE_PROFILE_COUNT) {
         return -ERANGE;
     }
 
@@ -281,12 +281,13 @@ int zmk_ble_prof_select(uint8_t index) {
 
 int zmk_ble_prof_next() {
     LOG_DBG("");
-    return zmk_ble_prof_select((active_profile + 1) % PROFILE_COUNT);
+    return zmk_ble_prof_select((active_profile + 1) % ZMK_BLE_PROFILE_COUNT);
 };
 
 int zmk_ble_prof_prev() {
     LOG_DBG("");
-    return zmk_ble_prof_select((active_profile + PROFILE_COUNT - 1) % PROFILE_COUNT);
+    return zmk_ble_prof_select((active_profile + ZMK_BLE_PROFILE_COUNT - 1) %
+                               ZMK_BLE_PROFILE_COUNT);
 };
 
 bt_addr_le_t *zmk_ble_active_profile_addr() { return &profiles[active_profile].peer; }
@@ -324,8 +325,9 @@ static int ble_profiles_handle_set(const char *name, size_t len, settings_read_c
             return -EINVAL;
         }
 
-        if (idx >= PROFILE_COUNT) {
-            LOG_WRN("Profile address for index %d is larger than max of %d", idx, PROFILE_COUNT);
+        if (idx >= ZMK_BLE_PROFILE_COUNT) {
+            LOG_WRN("Profile address for index %d is larger than max of %d", idx,
+                    ZMK_BLE_PROFILE_COUNT);
             return -EINVAL;
         }
 
@@ -591,7 +593,7 @@ static int zmk_ble_init(const struct device *_arg) {
         bt_unpair(i, NULL);
     }
 
-    for (int i = 0; i < PROFILE_COUNT; i++) {
+    for (int i = 0; i < ZMK_BLE_PROFILE_COUNT; i++) {
         char setting_name[15];
         sprintf(setting_name, "ble/profiles/%d", i);
 
diff --git a/app/src/keymap.c b/app/src/keymap.c
index 16ec316..8acc5ec 100644
--- a/app/src/keymap.c
+++ b/app/src/keymap.c
@@ -4,10 +4,6 @@
  * SPDX-License-Identifier: MIT
  */
 
-#define IS_BLE_CENTRAL                                                                             \
-    (IS_ENABLED(CONFIG_ZMK_SPLIT) && IS_ENABLED(CONFIG_ZMK_BLE) &&                                 \
-     IS_ENABLED(CONFIG_ZMK_SPLIT_BLE_ROLE_CENTRAL))
-
 #include <sys/util.h>
 #include <bluetooth/bluetooth.h>
 #include <logging/log.h>
@@ -19,7 +15,8 @@ LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 #include <drivers/behavior.h>
 #include <zmk/behavior.h>
 
-#if IS_BLE_CENTRAL
+#include <zmk/ble.h>
+#if ZMK_BLE_IS_CENTRAL
 #include <zmk/split/bluetooth/central.h>
 #endif
 
@@ -170,8 +167,8 @@ int invoke_locally(struct zmk_behavior_binding *binding, struct zmk_behavior_bin
     }
 }
 
-int zmk_keymap_apply_position_state(zmk_position_state_changed_source_t source, int layer,
-                                    uint32_t position, bool pressed, int64_t timestamp) {
+int zmk_keymap_apply_position_state(uint8_t source, int layer, uint32_t position, bool pressed,
+                                    int64_t timestamp) {
     // We want to make a copy of this, since it may be converted from
     // relative to absolute before being invoked
     struct zmk_behavior_binding binding = zmk_keymap[layer][position];
@@ -209,8 +206,8 @@ int zmk_keymap_apply_position_state(zmk_position_state_changed_source_t source,
     case BEHAVIOR_LOCALITY_CENTRAL:
         return invoke_locally(&binding, event, pressed);
     case BEHAVIOR_LOCALITY_EVENT_SOURCE:
-#if IS_BLE_CENTRAL
-        if (!bt_addr_le_cmp(source, BT_ADDR_LE_NONE)) {
+#if ZMK_BLE_IS_CENTRAL
+        if (source == UINT_MAX) {
             return invoke_locally(&binding, event, pressed);
         } else {
             return zmk_split_bt_invoke_behavior(source, &binding, event, pressed);
@@ -219,8 +216,10 @@ int zmk_keymap_apply_position_state(zmk_position_state_changed_source_t source,
         return invoke_locally(&binding, event, pressed);
 #endif
     case BEHAVIOR_LOCALITY_GLOBAL:
-#if IS_BLE_CENTRAL
-        zmk_split_bt_invoke_behavior(BT_ADDR_LE_ANY, &binding, event, pressed);
+#if ZMK_BLE_IS_CENTRAL
+        for (int i = 0; i < ZMK_BLE_SPLIT_PERIPHERAL_COUNT; i++) {
+            zmk_split_bt_invoke_behavior(i, &binding, event, pressed);
+        }
 #endif
         return invoke_locally(&binding, event, pressed);
     }
@@ -228,8 +227,8 @@ int zmk_keymap_apply_position_state(zmk_position_state_changed_source_t source,
     return -ENOTSUP;
 }
 
-int zmk_keymap_position_state_changed(zmk_position_state_changed_source_t source, uint32_t position,
-                                      bool pressed, int64_t timestamp) {
+int zmk_keymap_position_state_changed(uint8_t source, uint32_t position, bool pressed,
+                                      int64_t timestamp) {
     if (pressed) {
         zmk_keymap_active_behavior_layer[position] = _zmk_keymap_layer_state;
     }
diff --git a/app/src/kscan.c b/app/src/kscan.c
index 13ad2cc..3425fab 100644
--- a/app/src/kscan.c
+++ b/app/src/kscan.c
@@ -50,12 +50,11 @@ void zmk_kscan_process_msgq(struct k_work *item) {
         uint32_t position = zmk_matrix_transform_row_column_to_position(ev.row, ev.column);
         LOG_DBG("Row: %d, col: %d, position: %d, pressed: %s", ev.row, ev.column, position,
                 (pressed ? "true" : "false"));
-        ZMK_EVENT_RAISE(new_zmk_position_state_changed((struct zmk_position_state_changed) {
-#if IS_ENABLED(CONFIG_ZMK_BLE)
-            .source = BT_ADDR_LE_NONE,
-#endif
-            .state = pressed, .position = position, .timestamp = k_uptime_get()
-        }));
+        ZMK_EVENT_RAISE(new_zmk_position_state_changed(
+            (struct zmk_position_state_changed){.source = UINT8_MAX,
+                                                .state = pressed,
+                                                .position = position,
+                                                .timestamp = k_uptime_get()}));
     }
 }
 
diff --git a/app/src/split/bluetooth/central.c b/app/src/split/bluetooth/central.c
index c28941f..0d52d05 100644
--- a/app/src/split/bluetooth/central.c
+++ b/app/src/split/bluetooth/central.c
@@ -29,17 +29,112 @@ static int start_scan(void);
 
 #define POSITION_STATE_DATA_LEN 16
 
-static struct bt_conn *default_conn;
+enum peripheral_slot_state {
+    PERIPHERAL_SLOT_STATE_OPEN,
+    PERIPHERAL_SLOT_STATE_CONNECTING,
+    PERIPHERAL_SLOT_STATE_CONNECTED,
+};
+
+struct peripheral_slot {
+    enum peripheral_slot_state state;
+    struct bt_conn *conn;
+    struct bt_gatt_discover_params discover_params;
+    struct bt_gatt_subscribe_params subscribe_params;
+    struct bt_gatt_discover_params sub_discover_params;
+    uint16_t run_behavior_handle;
+    uint8_t position_state[POSITION_STATE_DATA_LEN];
+    uint8_t changed_positions[POSITION_STATE_DATA_LEN];
+};
+
+static struct peripheral_slot peripherals[ZMK_BLE_SPLIT_PERIPHERAL_COUNT];
 
 static const struct bt_uuid_128 split_service_uuid = BT_UUID_INIT_128(ZMK_SPLIT_BT_SERVICE_UUID);
-static struct bt_gatt_discover_params discover_params;
-static struct bt_gatt_subscribe_params subscribe_params;
-static struct bt_gatt_discover_params sub_discover_params;
-static uint16_t run_behavior_handle;
 
 K_MSGQ_DEFINE(peripheral_event_msgq, sizeof(struct zmk_position_state_changed),
               CONFIG_ZMK_SPLIT_BLE_CENTRAL_POSITION_QUEUE_SIZE, 4);
 
+int peripheral_slot_index_for_conn(struct bt_conn *conn) {
+    for (int i = 0; i < ZMK_BLE_SPLIT_PERIPHERAL_COUNT; i++) {
+        if (peripherals[i].conn == conn) {
+            return i;
+        }
+    }
+
+    return -EINVAL;
+}
+
+struct peripheral_slot *peripheral_slot_for_conn(struct bt_conn *conn) {
+    int idx = peripheral_slot_index_for_conn(conn);
+    if (idx < 0) {
+        return NULL;
+    }
+
+    return &peripherals[idx];
+}
+
+int release_peripheral_slot(int index) {
+    if (index < 0 || index >= ZMK_BLE_SPLIT_PERIPHERAL_COUNT) {
+        return -EINVAL;
+    }
+
+    struct peripheral_slot *slot = &peripherals[index];
+
+    if (slot->state == PERIPHERAL_SLOT_STATE_OPEN) {
+        return -EINVAL;
+    }
+
+    LOG_DBG("Releasing peripheral slot at %d", index);
+
+    if (slot->conn != NULL) {
+        bt_conn_unref(slot->conn);
+        slot->conn = NULL;
+    }
+    slot->state = PERIPHERAL_SLOT_STATE_OPEN;
+
+    for (int i = 0; i < POSITION_STATE_DATA_LEN; i++) {
+        slot->position_state[i] = 0U;
+        slot->changed_positions[i] = 0U;
+    }
+
+    // Clean up previously discovered handles;
+    slot->subscribe_params.value_handle = 0;
+    slot->run_behavior_handle = 0;
+
+    return 0;
+}
+
+int reserve_peripheral_slot() {
+    for (int i = 0; i < ZMK_BLE_SPLIT_PERIPHERAL_COUNT; i++) {
+        if (peripherals[i].state == PERIPHERAL_SLOT_STATE_OPEN) {
+            // Be sure the slot is fully reinitialized.
+            release_peripheral_slot(i);
+            peripherals[i].state = PERIPHERAL_SLOT_STATE_CONNECTING;
+            return i;
+        }
+    }
+
+    return -ENOMEM;
+}
+
+int release_peripheral_slot_for_conn(struct bt_conn *conn) {
+    int idx = peripheral_slot_index_for_conn(conn);
+    if (idx < 0) {
+        return idx;
+    }
+
+    return release_peripheral_slot(idx);
+}
+
+int confirm_peripheral_slot_conn(struct bt_conn *conn) {
+    int idx = peripheral_slot_index_for_conn(conn);
+    if (idx < 0) {
+        return idx;
+    }
+
+    peripherals[idx].state = PERIPHERAL_SLOT_STATE_CONNECTED;
+    return 0;
+}
+
 void peripheral_event_work_callback(struct k_work *work) {
     struct zmk_position_state_changed ev;
     while (k_msgq_get(&peripheral_event_msgq, &ev, K_NO_WAIT) == 0) {
@@ -53,9 +148,12 @@ K_WORK_DEFINE(peripheral_event_work, peripheral_event_work_callback);
 static uint8_t split_central_notify_func(struct bt_conn *conn,
                                          struct bt_gatt_subscribe_params *params, const void *data,
                                          uint16_t length) {
-    static uint8_t position_state[POSITION_STATE_DATA_LEN];
+    struct peripheral_slot *slot = peripheral_slot_for_conn(conn);
 
-    uint8_t changed_positions[POSITION_STATE_DATA_LEN];
+    if (slot == NULL) {
+        LOG_ERR("No peripheral state found for connection");
+        return BT_GATT_ITER_CONTINUE;
+    }
 
     if (!data) {
         LOG_DBG("[UNSUBSCRIBED]");
@@ -66,16 +164,18 @@ static uint8_t split_central_notify_func(struct bt_conn *conn,
     LOG_DBG("[NOTIFICATION] data %p length %u", data, length);
 
     for (int i = 0; i < POSITION_STATE_DATA_LEN; i++) {
-        changed_positions[i] = ((uint8_t *)data)[i] ^ position_state[i];
-        position_state[i] = ((uint8_t *)data)[i];
+        slot->changed_positions[i] = ((uint8_t *)data)[i] ^ slot->position_state[i];
+        slot->position_state[i] = ((uint8_t *)data)[i];
+        LOG_DBG("data: %d", slot->position_state[i]);
     }
 
     for (int i = 0; i < POSITION_STATE_DATA_LEN; i++) {
         for (int j = 0; j < 8; j++) {
-            if (changed_positions[i] & BIT(j)) {
+            if (slot->changed_positions[i] & BIT(j)) {
                 uint32_t position = (i * 8) + j;
-                bool pressed = position_state[i] & BIT(j);
-                struct zmk_position_state_changed ev = {.source = bt_conn_get_dst(conn),
+                bool pressed = slot->position_state[i] & BIT(j);
+                struct zmk_position_state_changed ev = {.source =
+                                                            peripheral_slot_index_for_conn(conn),
                                                         .position = position,
                                                         .state = pressed,
                                                         .timestamp = k_uptime_get()};
@@ -90,7 +190,13 @@ static uint8_t split_central_notify_func(struct bt_conn *conn,
 }
 
 static void split_central_subscribe(struct bt_conn *conn) {
-    int err = bt_gatt_subscribe(conn, &subscribe_params);
+    struct peripheral_slot *slot = peripheral_slot_for_conn(conn);
+    if (slot == NULL) {
+        LOG_ERR("No peripheral state found for connection");
+        return;
+    }
+
+    int err = bt_gatt_subscribe(conn, &slot->subscribe_params);
     switch (err) {
     case -EALREADY:
         LOG_DBG("[ALREADY SUBSCRIBED]");
@@ -117,28 +223,34 @@ static uint8_t split_central_chrc_discovery_func(struct bt_conn *conn,
         return BT_GATT_ITER_STOP;
     }
 
+    struct peripheral_slot *slot = peripheral_slot_for_conn(conn);
+    if (slot == NULL) {
+        LOG_ERR("No peripheral state found for connection");
+        return BT_GATT_ITER_STOP;
+    }
+
     LOG_DBG("[ATTRIBUTE] handle %u", attr->handle);
 
     if (!bt_uuid_cmp(((struct bt_gatt_chrc *)attr->user_data)->uuid,
                      BT_UUID_DECLARE_128(ZMK_SPLIT_BT_CHAR_POSITION_STATE_UUID))) {
         LOG_DBG("Found position state characteristic");
-        discover_params.uuid = NULL;
-        discover_params.start_handle = attr->handle + 2;
-        discover_params.type = BT_GATT_DISCOVER_CHARACTERISTIC;
-
-        subscribe_params.disc_params = &sub_discover_params;
-        subscribe_params.end_handle = discover_params.end_handle;
-        subscribe_params.value_handle = bt_gatt_attr_value_handle(attr);
-        subscribe_params.notify = split_central_notify_func;
-        subscribe_params.value = BT_GATT_CCC_NOTIFY;
+        slot->discover_params.uuid = NULL;
+        slot->discover_params.start_handle = attr->handle + 2;
+        slot->discover_params.type = BT_GATT_DISCOVER_CHARACTERISTIC;
+
+        slot->subscribe_params.disc_params = &slot->sub_discover_params;
+        slot->subscribe_params.end_handle = slot->discover_params.end_handle;
+        slot->subscribe_params.value_handle = bt_gatt_attr_value_handle(attr);
+        slot->subscribe_params.notify = split_central_notify_func;
+        slot->subscribe_params.value = BT_GATT_CCC_NOTIFY;
         split_central_subscribe(conn);
     } else if (!bt_uuid_cmp(((struct bt_gatt_chrc *)attr->user_data)->uuid,
                             BT_UUID_DECLARE_128(ZMK_SPLIT_BT_CHAR_RUN_BEHAVIOR_UUID))) {
         LOG_DBG("Found run behavior handle");
-        run_behavior_handle = bt_gatt_attr_value_handle(attr);
+        slot->run_behavior_handle = bt_gatt_attr_value_handle(attr);
     }
 
-    bool subscribed = (run_behavior_handle && subscribe_params.value_handle);
+    bool subscribed = (slot->run_behavior_handle && slot->subscribe_params.value_handle);
 
     return subscribed ? BT_GATT_ITER_STOP : BT_GATT_ITER_CONTINUE;
 }
@@ -154,18 +266,24 @@ static uint8_t split_central_service_discovery_func(struct bt_conn *conn,
 
     LOG_DBG("[ATTRIBUTE] handle %u", attr->handle);
 
-    if (bt_uuid_cmp(discover_params.uuid, BT_UUID_DECLARE_128(ZMK_SPLIT_BT_SERVICE_UUID))) {
+    struct peripheral_slot *slot = peripheral_slot_for_conn(conn);
+    if (slot == NULL) {
+        LOG_ERR("No peripheral state found for connection");
+        return BT_GATT_ITER_STOP;
+    }
+
+    if (bt_uuid_cmp(slot->discover_params.uuid, BT_UUID_DECLARE_128(ZMK_SPLIT_BT_SERVICE_UUID))) {
         LOG_DBG("Found other service");
         return BT_GATT_ITER_CONTINUE;
     }
 
     LOG_DBG("Found split service");
-    discover_params.uuid = NULL;
-    discover_params.func = split_central_chrc_discovery_func;
-    discover_params.start_handle = attr->handle + 1;
-    discover_params.type = BT_GATT_DISCOVER_CHARACTERISTIC;
+    slot->discover_params.uuid = NULL;
+    slot->discover_params.func = split_central_chrc_discovery_func;
+    slot->discover_params.start_handle = attr->handle + 1;
+    slot->discover_params.type = BT_GATT_DISCOVER_CHARACTERISTIC;
 
-    int err = bt_gatt_discover(conn, &discover_params);
+    int err = bt_gatt_discover(conn, &slot->discover_params);
     if (err) {
         LOG_ERR("Failed to start discovering split service characteristics (err %d)", err);
     }
@@ -183,14 +301,20 @@ static void split_central_process_connection(struct bt_conn *conn) {
         return;
     }
 
-    if (conn == default_conn && !subscribe_params.value_handle) {
-        discover_params.uuid = &split_service_uuid.uuid;
-        discover_params.func = split_central_service_discovery_func;
-        discover_params.start_handle = 0x0001;
-        discover_params.end_handle = 0xffff;
-        discover_params.type = BT_GATT_DISCOVER_PRIMARY;
+    struct peripheral_slot *slot = peripheral_slot_for_conn(conn);
+    if (slot == NULL) {
+        LOG_ERR("No peripheral state found for connection");
+        return;
+    }
 
-        err = bt_gatt_discover(default_conn, &discover_params);
+    if (!slot->subscribe_params.value_handle) {
+        slot->discover_params.uuid = &split_service_uuid.uuid;
+        slot->discover_params.func = split_central_service_discovery_func;
+        slot->discover_params.start_handle = 0x0001;
+        slot->discover_params.end_handle = 0xffff;
+        slot->discover_params.type = BT_GATT_DISCOVER_PRIMARY;
+
+        err = bt_gatt_discover(slot->conn, &slot->discover_params);
         if (err) {
             LOG_ERR("Discover failed(err %d)", err);
             return;
@@ -251,21 +375,33 @@ static bool split_central_eir_found(struct bt_data *data, void *user_data) {
                 continue;
             }
 
-            default_conn = bt_conn_lookup_addr_le(BT_ID_DEFAULT, addr);
-            if (default_conn) {
+            uint8_t slot_idx = reserve_peripheral_slot();
+            if (slot_idx < 0) {
+                LOG_ERR("Faild to reserve peripheral slot (err %d)", slot_idx);
+                continue;
+            }
+
+            struct peripheral_slot *slot = &peripherals[slot_idx];
+
+            slot->conn = bt_conn_lookup_addr_le(BT_ID_DEFAULT, addr);
+            if (slot->conn) {
                 LOG_DBG("Found existing connection");
-                split_central_process_connection(default_conn);
+                split_central_process_connection(slot->conn);
+                err = bt_conn_le_phy_update(slot->conn, BT_CONN_LE_PHY_PARAM_2M);
+                if (err) {
+                    LOG_ERR("Update phy conn failed (err %d)", err);
+                }
             } else {
                 param = BT_LE_CONN_PARAM(0x0006, 0x0006, 30, 400);
 
-                err = bt_conn_le_create(addr, BT_CONN_LE_CREATE_CONN, param, &default_conn);
+                err = bt_conn_le_create(addr, BT_CONN_LE_CREATE_CONN, param, &slot->conn);
                 if (err) {
                     LOG_ERR("Create conn failed (err %d) (create conn? 0x%04x)", err,
                             BT_HCI_OP_LE_CREATE_CONN);
                     start_scan();
                 }
 
-                err = bt_conn_le_phy_update(default_conn, BT_CONN_LE_PHY_PARAM_2M);
+                err = bt_conn_le_phy_update(slot->conn, BT_CONN_LE_PHY_PARAM_2M);
                 if (err) {
                     LOG_ERR("Update phy conn failed (err %d)", err);
                     start_scan();
@@ -314,8 +450,7 @@ static void split_central_connected(struct bt_conn *conn, uint8_t conn_err) {
     if (conn_err) {
         LOG_ERR("Failed to connect to %s (%u)", log_strdup(addr), conn_err);
 
-        bt_conn_unref(default_conn);
-        default_conn = NULL;
+        release_peripheral_slot_for_conn(conn);
 
         start_scan();
         return;
@@ -323,6 +458,7 @@ static void split_central_connected(struct bt_conn *conn, uint8_t conn_err) {
 
     LOG_DBG("Connected: %s", log_strdup(addr));
 
+    confirm_peripheral_slot_conn(conn);
     split_central_process_connection(conn);
 }
 
@@ -333,16 +469,7 @@ static void split_central_disconnected(struct bt_conn *conn, uint8_t reason) {
 
     LOG_DBG("Disconnected: %s (reason %d)", log_strdup(addr), reason);
 
-    if (default_conn != conn) {
-        return;
-    }
-
-    bt_conn_unref(default_conn);
-    default_conn = NULL;
-
-    // Clean up previously discovered handles;
-    subscribe_params.value_handle = 0;
-    run_behavior_handle = 0;
+    release_peripheral_slot_for_conn(conn);
 
     start_scan();
 }
@@ -357,16 +484,30 @@ K_THREAD_STACK_DEFINE(split_central_split_run_q_stack,
 
 struct k_work_q split_central_split_run_q;
 
-K_MSGQ_DEFINE(zmk_split_central_split_run_msgq, sizeof(struct zmk_split_run_behavior_payload),
+struct zmk_split_run_behavior_payload_wrapper {
+    uint8_t source;
+    struct zmk_split_run_behavior_payload payload;
+};
+
+K_MSGQ_DEFINE(zmk_split_central_split_run_msgq,
+              sizeof(struct zmk_split_run_behavior_payload_wrapper),
               CONFIG_ZMK_BLE_SPLIT_CENTRAL_SPLIT_RUN_QUEUE_SIZE, 4);
 
 void split_central_split_run_callback(struct k_work *work) {
-    struct zmk_split_run_behavior_payload payload;
+    struct zmk_split_run_behavior_payload_wrapper payload_wrapper;
 
-    while (k_msgq_get(&zmk_split_central_split_run_msgq, &payload, K_NO_WAIT) == 0) {
-        int err =
-            bt_gatt_write_without_response(default_conn, run_behavior_handle, &payload,
-                                           sizeof(struct zmk_split_run_behavior_payload), true);
+    LOG_DBG("");
+
+    while (k_msgq_get(&zmk_split_central_split_run_msgq, &payload_wrapper, K_NO_WAIT) == 0) {
+        if (peripherals[payload_wrapper.source].state != PERIPHERAL_SLOT_STATE_CONNECTED) {
+            LOG_ERR("Source not connected");
+            continue;
+        }
+
+        int err = bt_gatt_write_without_response(
+            peripherals[payload_wrapper.source].conn,
+            peripherals[payload_wrapper.source].run_behavior_handle, &payload_wrapper.payload,
+            sizeof(struct zmk_split_run_behavior_payload), true);
 
         if (err) {
             LOG_ERR("Failed to write the behavior characteristic (err %d)", err);
@@ -376,15 +517,18 @@ void split_central_split_run_callback(struct k_work *work) {
 
 K_WORK_DEFINE(split_central_split_run_work, split_central_split_run_callback);
 
-static int split_bt_invoke_behavior_payload(struct zmk_split_run_behavior_payload payload) {
-    int err = k_msgq_put(&zmk_split_central_split_run_msgq, &payload, K_MSEC(100));
+static int
+split_bt_invoke_behavior_payload(struct zmk_split_run_behavior_payload_wrapper payload_wrapper) {
+    LOG_DBG("");
+
+    int err = k_msgq_put(&zmk_split_central_split_run_msgq, &payload_wrapper, K_MSEC(100));
     if (err) {
         switch (err) {
         case -EAGAIN: {
             LOG_WRN("Consumer message queue full, popping first message and queueing again");
-            struct zmk_split_run_behavior_payload discarded_report;
+            struct zmk_split_run_behavior_payload_wrapper discarded_report;
             k_msgq_get(&zmk_split_central_split_run_msgq, &discarded_report, K_NO_WAIT);
-            return split_bt_invoke_behavior_payload(payload);
+            return split_bt_invoke_behavior_payload(payload_wrapper);
         }
         default:
             LOG_WRN("Failed to queue behavior to send (%d)", err);
@@ -397,18 +541,19 @@ static int split_bt_invoke_behavior_payload(struct zmk_split_run_behavior_payloa
     return 0;
 };
 
-int zmk_split_bt_invoke_behavior(const bt_addr_le_t *source, struct zmk_behavior_binding *binding,
+int zmk_split_bt_invoke_behavior(uint8_t source, struct zmk_behavior_binding *binding,
                                  struct zmk_behavior_binding_event event, bool state) {
     struct zmk_split_run_behavior_payload payload = {.data = {
                                                          .param1 = binding->param1,
                                                          .param2 = binding->param2,
                                                          .position = event.position,
-                                                         .state = state,
+                                                         .state = state ? 1 : 0,
                                                      }};
     strncpy(payload.behavior_dev, binding->behavior_dev, ZMK_SPLIT_RUN_BEHAVIOR_DEV_LEN - 1);
     payload.behavior_dev[ZMK_SPLIT_RUN_BEHAVIOR_DEV_LEN - 1] = '\0';
 
-    return split_bt_invoke_behavior_payload(payload);
+    struct zmk_split_run_behavior_payload_wrapper wrapper = {.source = source, .payload = payload};
+    return split_bt_invoke_behavior_payload(wrapper);
 }
 
 int zmk_split_bt_central_init(const struct device *_arg) {