fdt: Add a function to look up a /chosen property

It is sometimes useful to find a property in the chosen node. Add a function
for this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

diff --git a/include/fdtdec.h b/include/fdtdec.h
index 2de6dda..9fcc7a1 100644 (file)
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -628,7 +628,16 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
                         int *seqp);
 
 /**
- * Get the offset of the given chosen node
+ * Get a property from the /chosen node
+ *
+ * @param blob         Device tree blob (if NULL, then NULL is returned)
+ * @param name         Property name to look up
+ * @return Value of property, or NULL if it does not exist
+ */
+const char *fdtdec_get_chosen_prop(const void *blob, const char *name);
+
+/**
+ * Get the offset of the given /chosen node
  *
  * This looks up a property in /chosen containing the path to another node,
  * then finds the offset of that node.

diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 9db033a..e1df144 100644 (file)
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -601,16 +601,21 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int offset,
        return -ENOENT;
 }
 
-int fdtdec_get_chosen_node(const void *blob, const char *name)
+const char *fdtdec_get_chosen_prop(const void *blob, const char *name)
 {
-       const char *prop;
        int chosen_node;
-       int len;
 
        if (!blob)
-               return -FDT_ERR_NOTFOUND;
+               return NULL;
        chosen_node = fdt_path_offset(blob, "/chosen");
-       prop = fdt_getprop(blob, chosen_node, name, &len);
+       return fdt_getprop(blob, chosen_node, name, NULL);
+}
+
+int fdtdec_get_chosen_node(const void *blob, const char *name)
+{
+       const char *prop;
+
+       prop = fdtdec_get_chosen_prop(blob, name);
        if (!prop)
                return -FDT_ERR_NOTFOUND;
        return fdt_path_offset(blob, prop);