1 files changed, 30 insertions, 0 deletions
diff --git a/os/hal/include/hal_qei.h b/os/hal/include/hal_qei.h
index 92f03fc..1032c84 100644
--- a/os/hal/include/hal_qei.h
+++ b/os/hal/include/hal_qei.h
@@ -65,8 +65,36 @@ typedef struct QEIDriver QEIDriver;
  */
 typedef void (*qeicallback_t)(QEIDriver *qeip);
 
+/**
+ * @brief   Driver possible handling of counter overflow/underflow.
+ *
+ * @details When counter is going to overflow, the new value is
+ *          computed according to this mode in such a way that 
+ *          the counter will either wrap around, stay unchange 
+ *          or reach min/max
+ *
+ * @note    All driver implementation should support the
+ *          QEI_OVERFLOW_WRAP mode.
+ *
+ * @note    Mode QEI_OVERFLOW_DISCARD and QEI_OVERFLOW_MINMAX are included
+ *          if QEI_USE_OVERFLOW_DISCARD and QEI_USE_OVERFLOW_MINMAX are
+ *          set to TRUE in halconf_community.h and are not necessary supported
+ *          by all drivers
+ */
+typedef enum {
+  QEI_OVERFLOW_WRAP    = 0,     /**< Counter value will wrap around.        */
+#if QEI_USE_OVERFLOW_DISCARD == TRUE
+  QEI_OVERFLOW_DISCARD = 1,     /**< Counter doesn't change.                */
+#endif
+#if QEI_USE_OVERFLOW_MINMAX == TRUE
+  QEI_OVERFLOW_MINMAX  = 2,     /**< Counter will be updated upto min or max.*/
+#endif
+} qeioverflow_t;
+
+
 #include "hal_qei_lld.h"
 
+
 /*===========================================================================*/
 /* Driver macros.                                                            */
 /*===========================================================================*/
@@ -119,6 +147,8 @@ extern "C" {
   qeicnt_t qeiGetCount(QEIDriver *qeip);
   qeidelta_t qeiUpdate(QEIDriver *qeip);
   qeidelta_t qeiUpdateI(QEIDriver *qeip);
+  bool qei_adjust_count(qeicnt_t *count, qeidelta_t *delta,
+			qeicnt_t min, qeicnt_t max, qeioverflow_t mode);
 #ifdef __cplusplus
 }
 #endif