[nrf fromtree] Bluetooth: Host: Deprecate BT_FIXED_PASSKEY

The BT_FIXED_PASSKEY Kconfig option is being deprecated, and is replaced
by BT_APP_PASSKEY. The reason for the deprecation is an upcoming
errata, ES-24489, which mandates that a new passkey shall be generated
for each pairing procedure.

Signed-off-by: Håvard Reierstad <haavard.reierstad@nordicsemi.no>
(cherry picked from commit 82cfb5a)
Signed-off-by: alperen sener <alperen.sener@nordicsemi.no>

Author: HaavardRei

doc/releases/migration-guide-4.3.rst

@@ -123,6 +123,15 @@ Bluetooth HCI
 * The deprecated ``ipm`` value was removed from ``bt-hci-bus`` devicetree property.
   ``ipc`` should be used instead.
 
+Bluetooth Host
+==============
+
+* :kconfig:option:`CONFIG_BT_FIXED_PASSKEY` has been deprecated. Instead, the application can
+  provide passkeys for pairing using the :c:member:`bt_conn_auth_cb.app_passkey` callback, which is
+  available when :kconfig:option:`CONFIG_BT_APP_PASSKEY` is enabled. The application can return the
+  passkey for pairing, or :c:macro:`BT_PASSKEY_RAND` for the Host to generate a random passkey
+  instead.
+
 Ethernet
 ========
 

include/zephyr/bluetooth/conn.h

@@ -2380,8 +2380,8 @@ int bt_le_oob_get_sc_data(struct bt_conn *conn,
 			  const struct bt_le_oob_sc_data **oobd_remote);
 
 /**
- *  Special passkey value that can be used to disable a previously
- *  set fixed passkey.
+ *  DEPRECATED - use @ref BT_PASSKEY_RAND instead. Special passkey value that can be used to disable
+ *  a previously set fixed passkey.
  */
 #define BT_PASSKEY_INVALID 0xffffffff
 
@@ -2393,12 +2393,15 @@ int bt_le_oob_get_sc_data(struct bt_conn *conn,
  *  Sets a fixed passkey to be used for pairing. If set, the
  *  pairing_confirm() callback will be called for all incoming pairings.
  *
+ * @deprecated Use @ref BT_PASSKEY_RAND and the app_passkey callback from @ref bt_conn_auth_cb
+ *             instead.
+ *
  *  @param passkey A valid passkey (0 - 999999) or BT_PASSKEY_INVALID
  *                 to disable a previously set fixed passkey.
  *
  *  @return 0 on success or a negative error code on failure.
  */
-int bt_passkey_set(unsigned int passkey);
+__deprecated int bt_passkey_set(unsigned int passkey);
 
 /** Info Structure for OOB pairing */
 struct bt_conn_oob_info {

subsys/bluetooth/host/Kconfig

@@ -701,8 +701,10 @@ config BT_SMP_USB_HCI_CTLR_WORKAROUND
 	  if the keys are distributed over an encrypted link.
 
 config BT_FIXED_PASSKEY
-	bool "Use a fixed passkey for pairing"
+	bool "Use a fixed passkey for pairing [DEPRECATED]"
+	select DEPRECATED
 	help
+	  This option is deprecated, use BT_APP_PASSKEY instead.
 	  With this option enabled, the application will be able to call the
 	  bt_passkey_set() API to set a fixed passkey. If set, the
 	  pairing_confirm() callback will be called for all incoming pairings.