modbus: add an option to disable log

Introduce new configuration option that allow disable all logging functionality for FreeModBus.
This option is useful for small systems when we don't use any logging features.

Signed-off-by: raiden00pl <raiden00@railab.me>

modbus/Kconfig

@@ -251,4 +251,13 @@ config MB_MASTER_FUNC_READWRITE_HOLDING_ENABLED
 
 endif # MB_ASCII_MASTER || MB_RTU_MASTER
 endif # MODBUS
+
+config MODBUS_DISABLE_LOG
+	bool "Disable logging for FreeModBus"
+	default !FILE_STREAM
+	---help---
+		Disable all logging features for FreeModBus which can be useful
+		for small optimized systems without console or log file support.
+		This also must be enabled when fputs() is not supported.
+
 endmenu # FreeModBus

modbus/nuttx/port.h

@@ -79,8 +79,12 @@ typedef enum
 
 void vMBPortEnterCritical(void);
 void vMBPortExitCritical(void);
+#ifndef CONFIG_MODBUS_DISABLE_LOG
 void vMBPortLog(eMBPortLogLevel eLevel, const char *szModule,
                 const char *szFmt, ...) printf_like(3, 4);
+#else
+#  define vMBPortLog(l, m, c, ...)
+#endif
 void vMBPortTimerPoll(void);
 bool xMBPortSerialPoll(void);
 bool xMBPortSerialSetTimeout(uint32_t dwTimeoutMs);

modbus/nuttx/portother.c

@@ -73,6 +73,7 @@ void vMBPortLogFile(FILE * fNewLogFile)
   fLogFile = fNewLogFile;
 }
 
+#ifndef CONFIG_MODBUS_DISABLE_LOG
 void vMBPortLog(eMBPortLogLevel eLevel, const char * szModule,
                 const char * szFmt, ...)
 {
@@ -103,6 +104,7 @@ void vMBPortLog(eMBPortLogLevel eLevel, const char * szModule,
         }
     }
 }
+#endif
 
 void vMBPortEnterCritical(void)
 {