Add explicit reset

lib_xua/src/hid/hid_report_descriptor.c

@@ -143,33 +143,41 @@ void hidPrepareReportDescriptor( void )
     }
 }
 
+void hidResetReportDescriptor( void )
+{
+    hidReportDescriptorPrepared = 0;
+}
+
 unsigned hidSetReportItem( const unsigned byte, const unsigned bit, const unsigned char header, const unsigned char data[] )
 {
-    unsigned retVal = HID_STATUS_BAD_LOCATION;
+    unsigned retVal = HID_STATUS_IN_USE;
-    unsigned bSize = hidGetItemSize( header );
-    unsigned bTag  = hidGetItemTag ( header );
-    unsigned bType = hidGetItemType( header );
 
-    if(( HID_REPORT_ITEM_MAX_SIZE   <  bSize ) ||
+    if( !hidReportDescriptorPrepared ) {
-       ( HID_REPORT_ITEM_USAGE_TAG  != bTag  ) ||
+        retVal = HID_STATUS_BAD_LOCATION;
-       ( HID_REPORT_ITEM_USAGE_TYPE != bType )) {
+        unsigned bSize = hidGetItemSize( header );
-        retVal = HID_STATUS_BAD_HEADER;
+        unsigned bTag  = hidGetItemTag ( header );
-    } else {
+        unsigned bType = hidGetItemType( header );
-        for( unsigned itemIdx = 0; itemIdx < sizeof hidConfigurableItems / sizeof( USB_HID_Short_Item_t ); ++itemIdx ) {
-            USB_HID_Short_Item_t item = *hidConfigurableItems[ itemIdx ];
-            unsigned bBit  = hidGetItemBitLocation(  item.location );
-            unsigned bByte = hidGetItemByteLocation( item.location );
 
-            if(( bit == bBit ) && ( byte == bByte )) {
+        if(( HID_REPORT_ITEM_MAX_SIZE   <  bSize ) ||
-                item.header = header;
+           ( HID_REPORT_ITEM_USAGE_TAG  != bTag  ) ||
+           ( HID_REPORT_ITEM_USAGE_TYPE != bType )) {
+            retVal = HID_STATUS_BAD_HEADER;
+        } else {
+            for( unsigned itemIdx = 0; itemIdx < sizeof hidConfigurableItems / sizeof( USB_HID_Short_Item_t ); ++itemIdx ) {
+                USB_HID_Short_Item_t item = *hidConfigurableItems[ itemIdx ];
+                unsigned bBit  = hidGetItemBitLocation(  item.location );
+                unsigned bByte = hidGetItemByteLocation( item.location );
 
-                for( unsigned dataIdx = 0; dataIdx < bSize; ++dataIdx ) {
+                if(( bit == bBit ) && ( byte == bByte )) {
-                    item.data[ dataIdx ] = data[ dataIdx ];
+                    item.header = header;
+
+                    for( unsigned dataIdx = 0; dataIdx < bSize; ++dataIdx ) {
+                        item.data[ dataIdx ] = data[ dataIdx ];
+                    }
+
+                    *hidConfigurableItems[ itemIdx ] = item;
+                    retVal = HID_STATUS_GOOD;
                 }
-
-                *hidConfigurableItems[ itemIdx ] = item;
-                hidReportDescriptorPrepared = 0;
-                retVal = HID_STATUS_GOOD;
             }
         }
     }

lib_xua/src/hid/xua_hid_report_descriptor.h

@@ -4,7 +4,8 @@
 /**
  * @brief Human Interface Device (HID) Report descriptor
  *
- * This file defines the structure and default content of the HID Report descriptor.
+ * This file defines the structure of the HID Report descriptor and decalres
+ *   functions for manipulating it.
  * Document section numbers refer to the HID Device Class Definition, version 1.11.
  */
 
@@ -34,6 +35,7 @@
 #define HID_STATUS_GOOD                 ( 0 )
 #define HID_STATUS_BAD_HEADER           ( 1 )
 #define HID_STATUS_BAD_LOCATION         ( 2 )
+#define HID_STATUS_IN_USE               ( 3 )
 
 /**
  * @brief USB HID Report Descriptor. Short Item
@@ -84,11 +86,19 @@ size_t hidGetReportDescriptorLength( void );
  * @brief Prepare the USB HID Report descriptor
  *
  * After preparation, \c hidGetReportDescriptor() returns a list suitablefor transmission over USB.
- *
  * Call this function after altering one or more Report Items using \c hidSetReportItem().
  */
 void hidPrepareReportDescriptor( void );
 
+/**
+ * @brief Reset the USB HID Report descriptor
+ *
+ * After reset, \c hidGetReportDescriptor() returns NULL until a subsequent call to
+ *   \c hidPrepareReportDescriptor() occurs.
+ * Call this function before altering one or more Report Items using \c hidSetReportItem().
+ */
+void hidResetReportDescriptor( void );
+
 /**
  * @brief Modify a HID Report descriptor item
  *
@@ -109,6 +119,7 @@ void hidPrepareReportDescriptor( void );
  *                                      a Tag or Type inconsistent with a Usage Item
  * @retval \c HID_STATUS_BAD_LOCATION   The \a bit or \a byte arguments specify a location outside
  *                                      of the HID Report
+ * @retval \c HID_STATUS_IN_USE         The Report descriptor is in use
  */
 unsigned hidSetReportItem( const unsigned byte, const unsigned bit, const unsigned char header, const unsigned char data[] );