diff --git a/lib/libx52/x52_control.c b/lib/libx52/x52_control.c
index c42f50c..6cbadbb 100644
--- a/lib/libx52/x52_control.c
+++ b/lib/libx52/x52_control.c
@@ -262,6 +262,7 @@ static int _x52_write_time(libx52_device *x52, uint32_t bit)
     uint16_t value = 0;
     uint16_t index;
     libx52_clock_id clock;
+    uint16_t h24;
 
     switch (bit) {
     case X52_BIT_MFD_TIME:
@@ -276,9 +277,12 @@ static int _x52_write_time(libx52_device *x52, uint32_t bit)
         clock = LIBX52_CLOCK_3;
         index = X52_OFFS_CLOCK3;
         break;
+    default:
+        /* We should never get here, but put in a dummy case to satisfy the compiler */
+        return LIBX52_ERROR_INVALID_PARAM;
     }
 
-    uint16_t h24 = !!(x52->time_format[clock]);
+    h24 = !!(x52->time_format[clock]);
 
     if (clock != LIBX52_CLOCK_1) {
         value = libx52_calculate_clock_offset(x52, clock, h24);
diff --git a/lib/libx52/x52_core.c b/lib/libx52/x52_core.c
index 0d345d4..fe42c58 100644
--- a/lib/libx52/x52_core.c
+++ b/lib/libx52/x52_core.c
@@ -32,6 +32,8 @@ static int libx52_check_product(uint16_t idVendor, uint16_t idProduct)
         case X52_PROD_X52_2:
         case X52_PROD_X52PRO:
             return 1;
+        default:
+            return 0;
         }
     }
 
@@ -190,6 +192,8 @@ int libx52_check_feature(libx52_device *dev, libx52_feature feature)
         return tst_bit(&(dev->flags), X52_FLAG_IS_PRO) ?
             LIBX52_SUCCESS :
             LIBX52_ERROR_NOT_SUPPORTED;
+    default:
+        return LIBX52_ERROR_INVALID_PARAM;
     }
 
     return LIBX52_ERROR_INVALID_PARAM;
diff --git a/lib/libx52/x52_date_time.c b/lib/libx52/x52_date_time.c
index fb732aa..abb40a6 100644
--- a/lib/libx52/x52_date_time.c
+++ b/lib/libx52/x52_date_time.c
@@ -168,8 +168,11 @@ int libx52_set_clock_timezone(libx52_device *x52, libx52_clock_id clock, int off
         set_bit(&x52->update_mask, X52_BIT_MFD_OFFS2);
         break;
 
-    default:
+    case LIBX52_CLOCK_1:
         return LIBX52_ERROR_NOT_SUPPORTED;
+
+    default:
+        return LIBX52_ERROR_INVALID_PARAM;
     }
 
     return LIBX52_SUCCESS;
diff --git a/lib/libx52/x52_mfd_led.c b/lib/libx52/x52_mfd_led.c
index 4d9023f..a7f8074 100644
--- a/lib/libx52/x52_mfd_led.c
+++ b/lib/libx52/x52_mfd_led.c
@@ -58,7 +58,15 @@ static int x52pro_set_led_state(libx52_device *x52, libx52_led_id led, libx52_le
         }
         break;
 
-    default:
+    case LIBX52_LED_A:
+    case LIBX52_LED_B:
+    case LIBX52_LED_D:
+    case LIBX52_LED_E:
+    case LIBX52_LED_T1:
+    case LIBX52_LED_T2:
+    case LIBX52_LED_T3:
+    case LIBX52_LED_POV:
+    case LIBX52_LED_CLUTCH:
         /* All other LEDs support OFF, RED, AMBER and GREEN states
          * However, they are composed of individual RED and GREEN LEDs which
          * must be turned on or off individually.
@@ -84,15 +92,23 @@ static int x52pro_set_led_state(libx52_device *x52, libx52_led_id led, libx52_le
             set_bit(&x52->led_mask, led + 1); // Green
             break;
 
-        default:
+        case LIBX52_LED_STATE_ON:
             /* Cannot set the LED to "ON" */
             return LIBX52_ERROR_NOT_SUPPORTED;
+
+        default:
+            /* Any other state is not valid */
+            return LIBX52_ERROR_INVALID_PARAM;
         }
 
         /* Set the update mask bits */
         set_bit(&x52->update_mask, led + 0); // Red
         set_bit(&x52->update_mask, led + 1); // Green
         break;
+
+    default:
+        /* Any other LED is not valid */
+        return LIBX52_ERROR_INVALID_PARAM;
     }
 
     return LIBX52_SUCCESS;