fdt: Add function to return next compatible subnode

We need to iterate through subnodes of a parent, looking only at
compatible nodes. Add a utility function to do this for us.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

diff --git a/include/fdtdec.h b/include/fdtdec.h
index 84f0768..0351a25 100644 (file)
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -116,6 +116,23 @@ int fdtdec_next_alias(const void *blob, const char *name,
 int fdtdec_next_compatible(const void *blob, int node,
                enum fdt_compat_id id);
 
+/**
+ * Find the next compatible subnode for a peripheral.
+ *
+ * Do the first call with node set to the parent and depth = 0. This
+ * function will return the offset of the next compatible node. Next time
+ * you call this function, pass the node value returned last time, with
+ * depth unchanged, and the next node will be provided.
+ *
+ * @param blob         FDT blob to use
+ * @param node         Start node for search
+ * @param id           Compatible ID to look for (enum fdt_compat_id)
+ * @param depthp       Current depth (set to 0 before first call)
+ * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
+ */
+int fdtdec_next_compatible_subnode(const void *blob, int node,
+               enum fdt_compat_id id, int *depthp);
+
 /**
  * Look up an address property in a node and return it as an address.
  * The property must hold either one address with no trailing data or

diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 4a5ab71..76d3808 100644 (file)
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -133,6 +133,21 @@ int fdtdec_next_compatible(const void *blob, int node,
        return fdt_node_offset_by_compatible(blob, node, compat_names[id]);
 }
 
+int fdtdec_next_compatible_subnode(const void *blob, int node,
+               enum fdt_compat_id id, int *depthp)
+{
+       do {
+               node = fdt_next_node(blob, node, depthp);
+       } while (*depthp > 1);
+
+       /* If this is a direct subnode, and compatible, return it */
+       if (*depthp == 1 && 0 == fdt_node_check_compatible(
+                                               blob, node, compat_names[id]))
+               return node;
+
+       return -FDT_ERR_NOTFOUND;
+}
+
 int fdtdec_next_alias(const void *blob, const char *name,
                enum fdt_compat_id id, int *upto)
 {