Add QCanBusDevice::busStatus()

The original terminology is Error active, Error warning,
Error Passive and Bus Off. We map them to GoodStatus,
WarningStatus, ErrorStatus and BusOffStatus here.

[ChangeLog][QCanBusDevice] Added the function busStatus()
to query the CAN bus status from the CAN bus device.

Fixes: QTBUG-70766
Change-Id: I22b99e2a02a6b22509005dd177796b861d536281
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

3 files changed, 39 insertions, 2 deletions

diff --git a/examples/serialbus/can/mainwindow.cpp b/examples/serialbus/can/mainwindow.cpp
index b2bae6d..29c5f1f 100644
--- a/examples/serialbus/can/mainwindow.cpp
+++ b/examples/serialbus/can/mainwindow.cpp
@@ -60,7 +60,8 @@
 
 MainWindow::MainWindow(QWidget *parent) :
     QMainWindow(parent),
-    m_ui(new Ui::MainWindow)
+    m_ui(new Ui::MainWindow),
+    m_busStatusTimer(new QTimer(this))
 {
     m_ui->setupUi(this);
 
@@ -174,6 +175,31 @@ void MainWindow::connectDevice()
                     .arg(p.pluginName).arg(p.deviceInterfaceName));
         }
     }
+
+    connect(m_busStatusTimer, &QTimer::timeout, this, [this]() {
+        switch (m_canDevice->busStatus()) {
+        case QCanBusDevice::CanBusStatus::Good:
+            m_ui->busStatus->setText("CAN bus status: Good.");
+            break;
+        case QCanBusDevice::CanBusStatus::Warning:
+            m_ui->busStatus->setText("CAN bus status: Warning.");
+            break;
+        case QCanBusDevice::CanBusStatus::Error:
+            m_ui->busStatus->setText("CAN bus status: Error.");
+            break;
+        case QCanBusDevice::CanBusStatus::BusOff:
+            m_ui->busStatus->setText("CAN bus status: Bus Off.");
+            break;
+        default:
+            m_ui->busStatus->setText("CAN bus status: Unknown.");
+            break;
+        }
+    });
+
+    if (m_canDevice->hasBusStatus())
+        m_busStatusTimer->start(2000);
+    else
+        m_ui->busStatus->setText(tr("No CAN bus status available."));
 }
 
 void MainWindow::disconnectDevice()
@@ -181,6 +207,8 @@ void MainWindow::disconnectDevice()
     if (!m_canDevice)
         return;
 
+    m_busStatusTimer->stop();
+
     m_canDevice->disconnectDevice();
     delete m_canDevice;
     m_canDevice = nullptr;
diff --git a/examples/serialbus/can/mainwindow.h b/examples/serialbus/can/mainwindow.h
index 40b2e4a..673e87a 100644
--- a/examples/serialbus/can/mainwindow.h
+++ b/examples/serialbus/can/mainwindow.h
@@ -61,6 +61,7 @@ QT_BEGIN_NAMESPACE
 
 class QCanBusFrame;
 class QLabel;
+class QTimer;
 
 namespace Ui {
 class MainWindow;
@@ -96,6 +97,7 @@ private:
     QLabel *m_written = nullptr;
     ConnectDialog *m_connectDialog = nullptr;
     QCanBusDevice *m_canDevice = nullptr;
+    QTimer *m_busStatusTimer = nullptr;
 };
 
 #endif // MAINWINDOW_H
diff --git a/examples/serialbus/can/mainwindow.ui b/examples/serialbus/can/mainwindow.ui
index 2f61336..f773ffb 100644
--- a/examples/serialbus/can/mainwindow.ui
+++ b/examples/serialbus/can/mainwindow.ui
@@ -66,6 +66,13 @@
          </property>
         </widget>
        </item>
+       <item>
+        <widget class="QLabel" name="busStatus">
+         <property name="text">
+          <string/>
+         </property>
+        </widget>
+       </item>
       </layout>
      </widget>
     </item>
@@ -77,7 +84,7 @@
      <x>0</x>
      <y>0</y>
      <width>551</width>
-     <height>19</height>
+     <height>22</height>
     </rect>
    </property>
    <widget class="QMenu" name="menuCalls">