硬件驱动（VCOM）：增加获取USB虚拟串口连接状态的接口 (#5881)

* 硬件驱动（VCOM）：增加获取USB虚拟串口连接状态的接口

components/drivers/include/drivers/usb_device.h

@@ -62,6 +62,8 @@ extern "C" {
                                         }                                           \
                                     }while(0)
 
+#define RT_USBD_CLASS_CTRL_CONNECTED (RT_DEVICE_CTRL_BASE(USBDevice) + 0)
+
 struct ufunction;
 struct udevice;
 struct uendpoint;

components/drivers/usb/usbdevice/class/cdc_vcom.c

@@ -670,6 +670,12 @@ static rt_err_t _vcom_configure(struct rt_serial_device *serial,
 static rt_err_t _vcom_control(struct rt_serial_device *serial,
                               int cmd, void *arg)
 {
+    struct ufunction *func;
+    struct vcom *data;
+
+    func = (struct ufunction*)serial->parent.user_data;
+    data = (struct vcom*)func->user_data;
+
     switch (cmd)
     {
     case RT_DEVICE_CTRL_CLR_INT:
@@ -678,6 +684,9 @@ static rt_err_t _vcom_control(struct rt_serial_device *serial,
     case RT_DEVICE_CTRL_SET_INT:
         /* enable rx irq */
         break;
+    case RT_USBD_CLASS_CTRL_CONNECTED:
+        (*(rt_bool_t*)arg) = data->connected;
+        break;
     }
 
     return RT_EOK;