diff --git a/src/usb_moded-modesetting.c b/src/usb_moded-modesetting.c
index 31445ca..adc3805 100644
--- a/src/usb_moded-modesetting.c
+++ b/src/usb_moded-modesetting.c
@@ -105,7 +105,8 @@ static char *read_from_file(const char *path, size_t maxsize)
 }
 #endif /* LOG_ENABLE_DEBUG */
 
-int write_to_file(const char *path, const char *text)
+int write_to_file_real(const char *file, int line, const char *func,
+                       const char *path, const char *text)
 {
   int err = -1;
   int fd = -1;
@@ -130,7 +131,9 @@ int write_to_file(const char *path, const char *text)
   if(log_level >= LOG_DEBUG)
   {
     char *prev = read_from_file(path, 0x1000);
-    log_debug("WRITE '%s' : '%s' --> '%s'", path, prev ?: "???", text);
+    log_debug("%s:%d: %s(): WRITE '%s' : '%s' --> '%s'",
+              file, line, func,
+              path, prev ?: "???", text);
     free(prev);
   }
 #endif
diff --git a/src/usb_moded-modesetting.h b/src/usb_moded-modesetting.h
index 249f5a5..73af9ef 100644
--- a/src/usb_moded-modesetting.h
+++ b/src/usb_moded-modesetting.h
@@ -22,7 +22,11 @@
 
 #include "usb_moded-dyn-config.h"
 
-int write_to_file(const char *path, const char *text);
+int write_to_file_real(const char *file, int line, const char *func, const char *path, const char *text);
+
+#define write_to_file(path,text)\
+   write_to_file_real(__FILE__,__LINE__,__FUNCTION__,(path),(text))
+
 int set_mtp_mode(void);
 int set_dynamic_mode(void);
 void unset_dynamic_mode(void);