diff --git a/ff_dir.c b/ff_dir.c
index 8ea3c5c..1a80edf 100644
--- a/ff_dir.c
+++ b/ff_dir.c
@@ -2884,9 +2884,9 @@ FF_Error_t FF_ExtendDirectory( FF_IOManager_t * pxIOManager,
 
 /* *INDENT-OFF* */
 #if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
-    BaseType_t FF_IsNameCompliant( FF_T_WCHAR * pcName )
+    BaseType_t FF_IsNameCompliant( const FF_T_WCHAR * pcName )
 #else
-    BaseType_t FF_IsNameCompliant( char * pcName )
+    BaseType_t FF_IsNameCompliant( const char * pcName )
 #endif
 /* *INDENT-ON* */
 {
diff --git a/ff_fat.c b/ff_fat.c
index 4114e91..533cb01 100644
--- a/ff_fat.c
+++ b/ff_fat.c
@@ -712,7 +712,7 @@ uint32_t FF_FindEndOfChain( FF_IOManager_t * pxIOManager,
     {
         /* Traverse FAT for (2^32-1) items/clusters,
          * or until end-of-chain is encountered. */
-        ulFatEntry = FF_TraverseFAT( pxIOManager, ulStart, ( uint32_t ) ~0UL, &xError );
+        ulFatEntry = FF_TraverseFAT( pxIOManager, ulStart, ~( ( uint32_t ) 0U ), &xError );
     }
     else
     {
@@ -1496,7 +1496,7 @@ uint32_t FF_CountFreeClusters( FF_IOManager_t * pxIOManager,
                     {
                         ulFreeClusters = FF_getLong( pxBuffer->pucBuffer, 488 );
 
-                        if( ulFreeClusters != ~0ul )
+                        if( ulFreeClusters != ~( ( uint32_t ) 0U ) )
                         {
                             xInfoKnown = pdTRUE;
                         }
diff --git a/include/ff_dir.h b/include/ff_dir.h
index 4a23624..71d5b55 100644
--- a/include/ff_dir.h
+++ b/include/ff_dir.h
@@ -177,9 +177,9 @@ int8_t FF_PushEntry( FF_IOManager_t * pxIOManager,
  * contains any legal characters only.
  */
 #if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
-    BaseType_t FF_IsNameCompliant( FF_T_WCHAR * pcName );
+    BaseType_t FF_IsNameCompliant( const FF_T_WCHAR * pcName );
 #else
-    BaseType_t FF_IsNameCompliant( char * pcName );
+    BaseType_t FF_IsNameCompliant( const char * pcName );
 #endif
 
 static portINLINE BaseType_t FF_isEndOfDir( const uint8_t * pucEntryBuffer )