of/address: Add of_find_matching_node_by_address helper

of_find_matching_node_by_address() can be used to find a device tree
node for a device at a specific address.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 22 insertions, 0 deletions

diff --git a/drivers/of/address.c b/drivers/of/address.c
index b4559c58c095..da1f4b9605df 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -577,6 +577,24 @@ int of_address_to_resource(struct device_node *dev, int index,
 }
 EXPORT_SYMBOL_GPL(of_address_to_resource);
 
+struct device_node *of_find_matching_node_by_address(struct device_node *from,
+                                        const struct of_device_id *matches,
+                                        u64 base_address)
+{
+        struct device_node *dn = of_find_matching_node(from, matches);
+        struct resource res;
+
+        while (dn) {
+                if (of_address_to_resource(dn, 0, &res))
+                        continue;
+                if (res.start == base_address)
+                        return dn;
+                dn = of_find_matching_node(dn, matches);
+        }
+
+        return NULL;
+}
+
 
 /**
  * of_iomap - Maps the memory mapped IO for a given device_node
diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index 2feda6ee6140..bdfc20d8ff84 100644
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -6,6 +6,10 @@
 extern u64 of_translate_address(struct device_node *np, const __be32 *addr);
 extern int of_address_to_resource(struct device_node *dev, int index,
                                   struct resource *r);
+extern struct device_node *of_find_matching_node_by_address(
+                                        struct device_node *from,
+                                        const struct of_device_id *matches,
+                                        u64 base_address);
 extern void __iomem *of_iomap(struct device_node *device, int index);
 
 /* Extract an address from a device, returns the region size and