[modesetting] Log origin of sysfs writes in debug verbosity. JB#38433

When debugging configuration issues, it is sometimes hard to tell where the
various sysfs control writes are made from.

To ease debugging, log also call site when logging sysfs writes.

Signed-off-by: Simo Piiroinen <simo.piiroinen@jollamobile.com>

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

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);