dm: core: Allow dm_warn() to be used in SPL

At present this option is disabled in SPL, meaning that warnings are not
displayed. It is sometimes useful to see warnings in SPL for debugging
purposes.

Add a new Kconfig option to permit this.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/Kconfig

@@ -40,10 +40,24 @@ config DM_WARN
 	depends on DM
 	default y
 	help
+	  Enable this to see warnings related to driver model.
+
+	  Warnings may help with debugging, such as when expected devices do
+	  not bind correctly. If the option is disabled, dm_warn() is compiled
+	  out - it will do nothing when called.
+
+config SPL_DM_WARN
+	bool "Enable warnings in driver model wuth SPL"
+	depends on SPL_DM
+	help
+	  Enable this to see warnings related to driver model in SPL
+
 	  The dm_warn() function can use up quite a bit of space for its
 	  strings. By default this is disabled for SPL builds to save space.
-	  This will cause dm_warn() to be compiled out - it will do nothing
-	  when called.
+
+	  Warnings may help with debugging, such as when expected devices do
+	  not bind correctly. If the option is disabled, dm_warn() is compiled
+	  out - it will do nothing when called.
 
 config DM_DEBUG
 	bool "Enable debug messages in driver model core"

drivers/core/util.c

@@ -11,7 +11,7 @@
 #include <linux/libfdt.h>
 #include <vsprintf.h>
 
-#ifdef CONFIG_DM_WARN
+#if CONFIG_IS_ENABLED(DM_WARN)
 void dm_warn(const char *fmt, ...)
 {
 	va_list args;

include/config_uncmd_spl.h

@@ -16,7 +16,6 @@
 #undef CONFIG_DM_SPI
 #endif
 
-#undef CONFIG_DM_WARN
 #undef CONFIG_DM_STDIO
 
 #endif /* CONFIG_SPL_BUILD */

include/dm/util.h

@@ -6,7 +6,7 @@
 #ifndef __DM_UTIL_H
 #define __DM_UTIL_H
 
-#ifdef CONFIG_DM_WARN
+#if CONFIG_IS_ENABLED(DM_WARN)
 void dm_warn(const char *fmt, ...);
 #else
 static inline void dm_warn(const char *fmt, ...)