samples: bluetooth: fast_pair: locator_tag: remove rpa suspension API

Removed the app_fp_adv_rpa_rotation_suspend API from the Fast Pair
advertising module that is part of the Fast Pair Locator tag sample.
The module now handles the RPA suspension without the need for external
assistance.

Ref: NCSDK-30487

Signed-off-by: Kamil Piszczek <[email protected]>

Author: kapi-no

samples/bluetooth/fast_pair/locator_tag/include/app_fp_adv.h

@@ -81,13 +81,6 @@ void app_fp_adv_payload_refresh(void);
  */
 enum app_fp_adv_mode app_fp_adv_mode_get(void);
 
-/** Set the suspension mode for the RPA rotations of the Fast Pair advertising set.
- *
- *  @param suspended true if the RPA cannot change on the RPA timeout.
- *                   false if the RPA can change on the RPA timeout (default).
- */
-void app_fp_adv_rpa_rotation_suspend(bool suspended);
-
 /** Set the Bluetooth identity for the Fast Pair advertising.
  *
  *  This identity shall be created with the @ref bt_id_create function

samples/bluetooth/fast_pair/locator_tag/src/fp_adv.c

@@ -21,6 +21,11 @@
 #include <zephyr/logging/log.h>
 LOG_MODULE_DECLARE(fp_fmdn, LOG_LEVEL_INF);
 
+/* RPA suspension timeout in minutes for the Fast Pair advertising set
+ * as recommended by the FMDN specification.
+ */
+#define FP_ADV_RPA_SUSPENSION_TIMEOUT (5)
+
 /* Fast Pair advertising interval 100ms. */
 #define FP_ADV_INTERVAL (0x00A0)
 
@@ -35,6 +40,7 @@ static bool is_initialized;
 static bool is_enabled;
 
 static bool fmdn_provisioned;
+static bool fp_account_key_present;
 
 static struct bt_conn *fp_conn;
 static struct bt_le_ext_adv *fp_adv_set;
@@ -59,8 +65,28 @@ static struct bt_le_adv_param fp_adv_param = {
 };
 
 static void fp_adv_restart_work_handle(struct k_work *w);
+static void fp_adv_rpa_suspension_work_handle(struct k_work *w);
 
 static K_WORK_DEFINE(fp_adv_restart_work, fp_adv_restart_work_handle);
+static K_WORK_DELAYABLE_DEFINE(fp_adv_rpa_suspension_work, fp_adv_rpa_suspension_work_handle);
+
+static void fp_adv_rpa_rotation_suspended_set(bool suspended)
+{
+	fp_adv_rpa_rotation_suspended = suspended;
+
+	LOG_DBG("Fast Pair: set RPA rotation suspended to %s", suspended ? "true" : "false");
+}
+
+static void fp_adv_rpa_suspension_work_handle(struct k_work *w)
+{
+	fp_adv_rpa_rotation_suspended_set(false);
+}
+
+static void fp_adv_rpa_suspension_cancel(void)
+{
+	(void) k_work_cancel_delayable(&fp_adv_rpa_suspension_work);
+	fp_adv_rpa_rotation_suspended_set(false);
+}
 
 /* Reference to the Fast Pair advertising information callback structure. */
 static const struct app_fp_adv_info_cb *fast_pair_adv_info_cb;
@@ -469,26 +495,52 @@ BT_CONN_CB_DEFINE(conn_callbacks) = {
 
 static void fp_adv_provisioning_state_changed(bool provisioned)
 {
-	struct bt_le_oob oob;
-	int err;
-
 	fmdn_provisioned = provisioned;
 
+	if (!app_fp_adv_is_ready()) {
+		return;
+	}
+
 	if (!provisioned) {
+		int err;
+		struct bt_le_oob oob;
+
 		/* Force the RPA rotation to synchronize the Fast Pair advertising
-		 * payload with its RPA address using rpa_expired callback.
-		 */
+			* payload with its RPA address using rpa_expired callback.
+			*/
 		err = bt_le_oob_get_local(fp_adv_param.id, &oob);
 		if (err) {
 			LOG_ERR("Fast Pair: bt_le_oob_get_local failed: %d", err);
 		}
+	} else {
+		fp_adv_rpa_suspension_cancel();
 	}
 }
 
 static struct bt_fast_pair_fmdn_info_cb fmdn_info_cb = {
 	.provisioning_state_changed = fp_adv_provisioning_state_changed,
 };
 
+static void fp_adv_account_key_written(struct bt_conn *conn)
+{
+	/* The first and only Account Key write starts the FMDN provisioning. */
+	if (!fmdn_provisioned && !fp_account_key_present && app_fp_adv_is_ready()) {
+		/* Fast Pair Implementation Guidelines for the locator tag use case:
+		 * after the Provider was paired, it should not change its MAC address
+		 * till FMDN is provisioned or till 5 minutes passes.
+		 */
+		fp_adv_rpa_rotation_suspended_set(true);
+		(void) k_work_schedule(&fp_adv_rpa_suspension_work,
+					K_MINUTES(FP_ADV_RPA_SUSPENSION_TIMEOUT));
+	}
+
+	fp_account_key_present = bt_fast_pair_has_account_key();
+}
+
+static struct bt_fast_pair_info_cb fp_info_callbacks = {
+	.account_key_written = fp_adv_account_key_written,
+};
+
 enum app_fp_adv_mode app_fp_adv_mode_get(void)
 {
 	return fp_adv_mode;
@@ -528,12 +580,11 @@ static void fp_adv_mode_set(enum app_fp_adv_mode adv_mode)
 
 static void fp_adv_mode_update(void)
 {
-	bool has_account_key = bt_fast_pair_has_account_key();
 	bool is_any_request_enabled = (fp_adv_request_bm != 0);
 	enum app_fp_adv_mode requested_mode;
 
 	if (is_any_request_enabled) {
-		requested_mode = has_account_key ?
+		requested_mode = fp_account_key_present ?
 				 APP_FP_ADV_MODE_NOT_DISCOVERABLE :
 				 APP_FP_ADV_MODE_DISCOVERABLE;
 	} else {
@@ -581,11 +632,6 @@ void app_fp_adv_payload_refresh(void)
 	}
 }
 
-void app_fp_adv_rpa_rotation_suspend(bool suspended)
-{
-	fp_adv_rpa_rotation_suspended = suspended;
-}
-
 int app_fp_adv_id_set(uint8_t id)
 {
 	if (app_fp_adv_is_ready()) {
@@ -616,6 +662,12 @@ int app_fp_adv_init(void)
 		return err;
 	}
 
+	err = bt_fast_pair_info_cb_register(&fp_info_callbacks);
+	if (err) {
+		LOG_ERR("Fast Pair: bt_fast_pair_info_cb_register failed (err %d)", err);
+		return err;
+	}
+
 	STRUCT_SECTION_COUNT(app_fp_adv_trigger, &trigger_cnt);
 	__ASSERT_NO_MSG(trigger_cnt <= BITS_PER_VAR(fp_adv_request_bm));
 
@@ -642,6 +694,8 @@ int app_fp_adv_enable(void)
 		return err;
 	}
 
+	fp_account_key_present = bt_fast_pair_has_account_key();
+
 	fp_adv_mode_update();
 
 	is_enabled = true;
@@ -664,6 +718,9 @@ int app_fp_adv_disable(void)
 
 	is_enabled = false;
 
+	/* Reset the RPA suspension. */
+	fp_adv_rpa_suspension_cancel();
+
 	/* Suspend the requested advertising until the fp_adv module reinitializes. */
 	fp_adv_mode_set(APP_FP_ADV_MODE_OFF);
 

samples/bluetooth/fast_pair/locator_tag/src/main.c

@@ -90,8 +90,6 @@ static void fmdn_factory_reset_prepare(void)
 	/* Disable advertising request from the UI. */
 	fp_adv_ui_request = false;
 	app_fp_adv_request(&fp_adv_trigger_ui, fp_adv_ui_request);
-
-	app_fp_adv_rpa_rotation_suspend(false);
 }
 
 static void fmdn_factory_reset_executed(void)
@@ -206,12 +204,6 @@ static void fp_account_key_written(struct bt_conn *conn)
 		fmdn_factory_reset_schedule(
 			FACTORY_RESET_TRIGGER_PROVISIONING_TIMEOUT,
 			K_MINUTES(FMDN_PROVISIONING_TIMEOUT));
-
-		/* Fast Pair Implementation Guidelines for the locator tag use case:
-		 * after the Provider was paired, it should not change its MAC address
-		 * till FMDN is provisioned or till 5 minutes passes.
-		 */
-		app_fp_adv_rpa_rotation_suspend(true);
 	}
 
 	fp_account_key_present = bt_fast_pair_has_account_key();
@@ -380,7 +372,6 @@ static void fmdn_provisioning_state_changed(bool provisioned)
 	if (provisioned &&
 	    (factory_reset_trigger == FACTORY_RESET_TRIGGER_PROVISIONING_TIMEOUT)) {
 		fmdn_factory_reset_cancel();
-		app_fp_adv_rpa_rotation_suspend(false);
 	}
 
 	/* Fast Pair Implementation Guidelines for the locator tag use case: