bluetooth: Add BLE scan compatible option for legacy device

Allow connection to legacy peripheral device that do not support a Window offset parameter of 0 in the Link Layer CONNECT_IND packet.
sonydevworld · Dec 2, 2024 · e57be0e · e57be0e
1 parent ab1502b
commit e57be0e
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diff --git a/sdk/modules/bluetooth/hal/nrf52/Kconfig b/sdk/modules/bluetooth/hal/nrf52/Kconfig
@@ -32,6 +32,15 @@ config NRF52_LESC
 		This option enables LE secure connection feature of nRF52.
 		LE secure connection is the safer pairing method,
 		but nrf52 needs more memory because mbedtls or micro-ecc is required.
+
+config NRF52_SCAN_COMPAT_MODE
+	bool "Enable scan compatible mode"
+	default n
+	---help---
+		Enable interoperability with devices that do not support a value of
+		0 for the WinOffset parameter in the Link Layer CONNECT_IND packet.
+		This applies to a limited set of legacy peripheral devices.
+
 endif # NRF52_LE
 
 endif # BLUETOOTH_NRF52
diff --git a/sdk/modules/bluetooth/hal/nrf52/ble_gap.c b/sdk/modules/bluetooth/hal/nrf52/ble_gap.c
@@ -603,6 +603,21 @@ static int8_t ble_gap_scan_tx_power = 0;
 uint8_t bleAdvReportBuffer[BLE_GAP_SCAN_BUFFER_EXTENDED_MIN];
 #endif
 
+int BLE_GapSetScanCompatMode(bool enable)
+{
+  int ret     = BLE_SUCCESS;
+  int errCode = 0;
+  ble_opt_t opt;
+
+  memset(&opt, 0x0, sizeof(opt));
+  opt.gap_opt.compat_mode_1.enable = enable ? 1 : 0;
+
+  errCode = sd_ble_opt_set(BLE_GAP_OPT_COMPAT_MODE_1, &opt);
+  ret = bleConvertErrorCode((uint32_t)errCode);
+
+  return ret;
+}
+
 int BLE_GapSetScanParam(struct ble_scan_param_s *scanParam)
 {
   if(scanParam == NULL) {
@@ -635,6 +650,15 @@ int BLE_GapStartScan(void)
     gapMem.scanParams.window   = SCAN_WINDOW;
     gapMem.scanParams.timeout  = SCAN_TIMEOUT;
   }
+
+#ifdef CONFIG_NRF52_SCAN_COMPAT_MODE
+  /* Allow connection to legacy peripheral device that do not support
+   * a Window offset parameter of 0.
+   */
+
+  BLE_GapSetScanCompatMode(true);
+#endif
+
 #if NRF_SD_BLE_API_VERSION > 5
   /* Always use the fixed value. */
 

diff --git a/sdk/modules/bluetooth/hal/nrf52/include/ble/ble_gap.h b/sdk/modules/bluetooth/hal/nrf52/include/ble/ble_gap.h
@@ -745,6 +745,24 @@ int BLE_GapExchangePairingFeature(BLE_GapConnHandle connHandle,
                                   BLE_GapPairingFeature *ownFeature,
                                   const BLE_GapPairingFeature *peerFeature);
 
+/**@brief   Set scan compatible mode option
+ * @details Allow connection to legacy peripheral device that do not support
+ *          a Window offset parameter of 0. This enables compatibility mode 1
+ *          option for nrf52 softdevice.
+ *
+ * @param[in]  enable: enable if true, disable if false (default: disable)
+ * @return     0: success
+ *
+ * @par Blocking
+ *     Yes
+ * @par Context
+ *     Task
+ * @par Reentrant
+ *     No
+ *
+ */
+int BLE_GapSetScanCompatMode(bool enable);
+
 /**@brief   Set scan parameter
  * @details This call allows the application to set scan paramter, use the default scan parameter
  *          (interval:200,  window:20, timeout:60) if the call of this API is failed or not call this API.