Fix Analog gauge glitches on FreeRTOS for xdrv_92_vid6608 driver (#24189)

* Fix Analog gauge glitches on FreeRTOS for xdrv_92_vid6608 driver

Original version assumed position and command as thread safe, but it is not true. Wrong readings lead to random move back and forth. Patch was made and tested on real device.

* Add mutex to protect vid6608 from update/command
* Fix verious glitches

* xdrv_92_vid6608: do not create mutex, if no drives found

Author: petrows

tasmota/tasmota_xdrv_driver/xdrv_92_vid6608.ino

@@ -108,6 +108,23 @@ enum GaugeInternalCommand {
 bool vid6608Present = false;
 float vid6608StepsFloat = VID6608_DEFAULT_MAX_STEPS;
 vid6608 *vid6608Drives[VID6608_MAX_DRIVES];
+#ifdef VID6608_RTOS
+  /**
+   * @brief Mutex for RTOS precision timing
+   *
+   * We have to use "real" trheads under FreeRTOS, as precision timing is required
+   * for stepper motor driving. This mutex protects data access from multiple
+   * threads simultaniously. Else it will lead to stepper motor glitches and random move.
+   *
+   */
+  SemaphoreHandle_t vid6608Mutex;
+  // Macro for mutexs take/give
+  #define VID6608_MUTEX_TAKE   xSemaphoreTake(vid6608Mutex, portMAX_DELAY);
+  #define VID6608_MUTEX_GIVE   xSemaphoreGive(vid6608Mutex);
+#else
+  #define VID6608_MUTEX_TAKE
+  #define VID6608_MUTEX_GIVE
+#endif
 
 /**
  * @brief Command Gauge
@@ -148,6 +165,7 @@ void CmndGaugeZero(void) {
  * @param payload command argument
  */
 void CmndGaugeCommand(int32_t command, uint32_t index, int32_t payload) {
+  VID6608_MUTEX_TAKE
   Response_P(PSTR("{\"" D_PRFX_GAUGE "\":{"));
   bool isFirstItem = true;
   for (uint8_t x = 0; x < VID6608_MAX_DRIVES; x++) {
@@ -179,6 +197,7 @@ void CmndGaugeCommand(int32_t command, uint32_t index, int32_t payload) {
     }
   }
   ResponseAppend_P(PSTR("}}"));
+  VID6608_MUTEX_GIVE
 }
 
 /**
@@ -188,6 +207,7 @@ void CmndGaugeCommand(int32_t command, uint32_t index, int32_t payload) {
 void VID6608StatusJson() {
   ResponseAppend_P(PSTR("\"" D_PRFX_GAUGE "\":{"));
   bool isFirstItem = true;
+  VID6608_MUTEX_TAKE
   for (uint8_t x = 0; x < VID6608_MAX_DRIVES; x++) {
     vid6608 *driver = vid6608Drives[x];
     if (driver) {
@@ -198,6 +218,7 @@ void VID6608StatusJson() {
       isFirstItem = false;
     }
   }
+  VID6608_MUTEX_GIVE
   ResponseJsonEnd();
 }
 
@@ -208,12 +229,14 @@ void VID6608StatusJson() {
  */
 void VID6608StatusWeb() {
   WSContentSend_PD(HTTP_TABLE100);
+  VID6608_MUTEX_TAKE
   for (uint8_t x = 0; x < VID6608_MAX_DRIVES; x++) {
     vid6608 *driver = vid6608Drives[x];
     if (driver) {
       WSContentSend_PD(PSTR("<tr><th>Gauge %d</th><td>%d</td></tr>"), (int32_t)(x+1), (int32_t)driver->getPosition());
     }
   }
+  VID6608_MUTEX_GIVE
   WSContentSend_PD(PSTR("</table>"));
 }
 #endif
@@ -227,6 +250,7 @@ void VID6608StatusWeb() {
 void VID6608XvTask(void *) {
   while(true) {
     bool needToMove = false;
+    VID6608_MUTEX_TAKE
     for (uint8_t x = 0; x < VID6608_MAX_DRIVES; x++) {
       vid6608 *driver = vid6608Drives[x];
       if (driver) {
@@ -236,6 +260,7 @@ void VID6608XvTask(void *) {
         }
       }
     }
+    VID6608_MUTEX_GIVE
     /*
       If we dont need to move any -> go sleep.
       This will delay next move begin up to 500ms, but freeds up CPU a lot.
@@ -274,6 +299,8 @@ void VID6608Init() {
     return;
   }
 #ifdef VID6608_RTOS
+  // Create mutex for RTOS thread safety
+  vid6608Mutex = xSemaphoreCreateMutex();
   // Start background RTOS thread -> required for precision timing
   xTaskCreate(
     VID6608XvTask,                /* Function to implement the task */