From feb38e2ccdac2d60709f09a8457a7a01a0ba97bf Mon Sep 17 00:00:00 2001
From: Xudong Zheng <7pkvm5aw@slicealias.com>
Date: Tue, 21 Jan 2025 00:52:01 -0500
Subject: [PATCH 1/2] fix(ble): enforce maximum length for dynamic device name

---
 app/Kconfig   | 5 +++++
 app/src/ble.c | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/app/Kconfig b/app/Kconfig
index 5fc03822a02..c1d88a584f7 100644
--- a/app/Kconfig
+++ b/app/Kconfig
@@ -238,6 +238,11 @@ config BT_PERIPHERAL_PREF_LATENCY
 config BT_PERIPHERAL_PREF_TIMEOUT
     default 400
 
+# The device name should be 16 characters or less so it fits within the
+# advertising data.
+config BT_DEVICE_NAME_MAX
+    default 16
+
 endif # ZMK_BLE
 
 endmenu # Output Types
diff --git a/app/src/ble.c b/app/src/ble.c
index 02d8901b982..7176bd0a67c 100644
--- a/app/src/ble.c
+++ b/app/src/ble.c
@@ -66,7 +66,9 @@ static uint8_t active_profile;
 #define DEVICE_NAME CONFIG_BT_DEVICE_NAME
 #define DEVICE_NAME_LEN (sizeof(DEVICE_NAME) - 1)
 
-BUILD_ASSERT(DEVICE_NAME_LEN <= 16, "ERROR: BLE device name is too long. Max length: 16");
+BUILD_ASSERT(
+    DEVICE_NAME_LEN <= CONFIG_BT_DEVICE_NAME_MAX,
+    "ERROR: BLE device name is too long. Max length: " STRINGIFY(CONFIG_BT_DEVICE_NAME_MAX));
 
 static struct bt_data zmk_ble_ad[] = {
     BT_DATA_BYTES(BT_DATA_GAP_APPEARANCE, 0xC1, 0x03),

From a64d2c2a5df6b7d7fd2572d18e1ffa551ed1dff6 Mon Sep 17 00:00:00 2001
From: Xudong Zheng <7pkvm5aw@slicealias.com>
Date: Tue, 21 Jan 2025 01:33:19 -0500
Subject: [PATCH 2/2] feat(ble): add support for generating device name based
 on MAC address

This is useful for distinguishing multiple identical keyboards.
---
 app/Kconfig   |  4 ++++
 app/src/ble.c | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/app/Kconfig b/app/Kconfig
index c1d88a584f7..5dfc25bf085 100644
--- a/app/Kconfig
+++ b/app/Kconfig
@@ -243,6 +243,10 @@ config BT_PERIPHERAL_PREF_TIMEOUT
 config BT_DEVICE_NAME_MAX
     default 16
 
+config ZMK_BLE_KEYBOARD_NAME_MAC
+    bool "Include MAC address in BLE device name"
+    depends on ZMK_SPLIT_ROLE_CENTRAL
+
 endif # ZMK_BLE
 
 endmenu # Output Types
diff --git a/app/src/ble.c b/app/src/ble.c
index 7176bd0a67c..5c2c87eb661 100644
--- a/app/src/ble.c
+++ b/app/src/ble.c
@@ -702,6 +702,24 @@ static int zmk_ble_complete_startup(void) {
 
 #endif // IS_ENABLED(CONFIG_ZMK_BLE_CLEAR_BONDS_ON_START)
 
+#if IS_ENABLED(CONFIG_ZMK_BLE_KEYBOARD_NAME_MAC)
+    bt_addr_le_t addrs[CONFIG_BT_ID_MAX];
+    size_t id_count;
+    bt_id_get(addrs, &id_count);
+    if (id_count < 1) {
+        LOG_ERR("Failed to get Bluetooth device address");
+    } else {
+        // The generated name can be a maximum of 29 bytes (plus NULL) since
+        // CONFIG_BT_DEVICE_NAME is 16 bytes at most.
+        char name[30] = {};
+        uint8_t *a = addrs[0].a.val;
+        snprintf(name, sizeof(name), "%s %02X%02X%02X%02X%02X%02X", CONFIG_BT_DEVICE_NAME, a[5],
+                 a[4], a[3], a[2], a[1], a[0]);
+        name[CONFIG_BT_DEVICE_NAME_MAX] = '\0';
+        zmk_ble_set_device_name(name);
+    }
+#endif
+
     bt_conn_cb_register(&conn_callbacks);
     bt_conn_auth_cb_register(&zmk_ble_auth_cb_display);
     bt_conn_auth_info_cb_register(&zmk_ble_auth_info_cb_display);