feat(app): 添加蓝牙电量模块支持

- 在CMakeLists.txt中添加ble_battery_module.c源文件
- 实现BLE电池服务模块，提供电池电量GATT服务
- 支持电池电量读取和通知功能
- 集成到应用事件管理器，监听电池状态事件
- 当蓝牙连接就绪时设置模块状态为READY

CMakeLists.txt

@@ -25,6 +25,7 @@ target_sources(app PRIVATE
     src/events/mode_event.c
     src/modules/battery_module.c
     src/modules/ble_adv_ctrl_module.c
+    src/modules/ble_battery_module.c
     src/modules/ble_bond_module.c
     src/modules/keyboard_module.c
     src/modules/led_state_module.c

src/modules/ble_battery_module.c

@@ -0,0 +1,91 @@
+#include <errno.h>
+
+#include <zephyr/kernel.h>
+#include <zephyr/bluetooth/gatt.h>
+
+#include <app_event_manager.h>
+
+#define MODULE ble_battery
+#include <caf/events/module_state_event.h>
+
+#include "battery_status_event.h"
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(MODULE, LOG_LEVEL_INF);
+
+static bool notify_enabled;
+static uint8_t battery_level = 100U;
+
+static void bas_ccc_cfg_changed(const struct bt_gatt_attr *attr, uint16_t value)
+{
+	ARG_UNUSED(attr);
+	notify_enabled = (value == BT_GATT_CCC_NOTIFY);
+}
+
+static ssize_t read_battery_level(struct bt_conn *conn,
+				  const struct bt_gatt_attr *attr,
+				  void *buf,
+				  uint16_t len,
+				  uint16_t offset)
+{
+	const uint8_t *value = attr->user_data;
+
+	return bt_gatt_attr_read(conn, attr, buf, len, offset, value, sizeof(*value));
+}
+
+BT_GATT_SERVICE_DEFINE(ble_battery_svc,
+	BT_GATT_PRIMARY_SERVICE(BT_UUID_BAS),
+	BT_GATT_CHARACTERISTIC(BT_UUID_BAS_BATTERY_LEVEL,
+			       BT_GATT_CHRC_READ | BT_GATT_CHRC_NOTIFY,
+			       BT_GATT_PERM_READ_ENCRYPT,
+			       read_battery_level, NULL, &battery_level),
+	BT_GATT_CCC(bas_ccc_cfg_changed,
+		    BT_GATT_PERM_READ_ENCRYPT | BT_GATT_PERM_WRITE_ENCRYPT),
+);
+
+static bool handle_battery_status_event(const struct battery_status_event *event)
+{
+	battery_level = event->soc;
+
+	if (!notify_enabled) {
+		return false;
+	}
+
+	int err = bt_gatt_notify(NULL, &ble_battery_svc.attrs[1], &battery_level, sizeof(battery_level));
+
+	if (err == -ENOTCONN) {
+		LOG_WRN("BAS notify skipped: peer disconnecting");
+	} else if (err) {
+		LOG_ERR("BAS notify failed: %d", err);
+	}
+
+	return false;
+}
+
+static bool handle_module_state_event(const struct module_state_event *event)
+{
+	if (!check_state(event, MODULE_ID(ble_state), MODULE_STATE_READY)) {
+		return false;
+	}
+
+	module_set_state(MODULE_STATE_READY);
+	return false;
+}
+
+static bool app_event_handler(const struct app_event_header *aeh)
+{
+	if (is_battery_status_event(aeh)) {
+		return handle_battery_status_event(cast_battery_status_event(aeh));
+	}
+
+	if (is_module_state_event(aeh)) {
+		return handle_module_state_event(cast_module_state_event(aeh));
+	}
+
+	__ASSERT_NO_MSG(false);
+	return false;
+}
+
+APP_EVENT_LISTENER(MODULE, app_event_handler);
+APP_EVENT_SUBSCRIBE(MODULE, battery_status_event);
+APP_EVENT_SUBSCRIBE(MODULE, module_state_event);