dt: add of_platform_populate() for creating device from the device tree

of_platform_populate() is similar to of_platform_bus_probe() except
that it strictly enforces that all device nodes must have a compatible
property, and it can be used to register devices (not buses) which are
children of the root node.

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

2 files changed, 53 insertions, 4 deletions

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index bb483ef32e00..1f4a5d3af76e 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -229,19 +229,26 @@ EXPORT_SYMBOL(of_platform_device_create);
  */
 static int of_platform_bus_create(struct device_node *bus,
                                   const struct of_device_id *matches,
-                                  struct device *parent)
+                                  struct device *parent, bool strict)
 {
         struct device_node *child;
         struct platform_device *dev;
         int rc = 0;
 
+        /* Make sure it has a compatible property */
+        if (strict && (!of_get_property(bus, "compatible", NULL))) {
+                pr_debug("%s() - skipping %s, no compatible prop\n",
+                         __func__, bus->full_name);
+                return 0;
+        }
+
         dev = of_platform_device_create(bus, NULL, parent);
         if (!dev || !of_match_node(matches, bus))
                 return 0;
 
         for_each_child_of_node(bus, child) {
                 pr_debug("   create child: %s\n", child->full_name);
-                rc = of_platform_bus_create(child, matches, &dev->dev);
+                rc = of_platform_bus_create(child, matches, &dev->dev, strict);
                 if (rc) {
                         of_node_put(child);
                         break;
@@ -275,11 +282,11 @@ int of_platform_bus_probe(struct device_node *root,
 
         /* Do a self check of bus type, if there's a match, create children */
         if (of_match_node(matches, root)) {
-                rc = of_platform_bus_create(root, matches, parent);
+                rc = of_platform_bus_create(root, matches, parent, false);
         } else for_each_child_of_node(root, child) {
                 if (!of_match_node(matches, child))
                         continue;
-                rc = of_platform_bus_create(child, matches, parent);
+                rc = of_platform_bus_create(child, matches, parent, false);
                 if (rc)
                         break;
         }
@@ -288,4 +295,43 @@ int of_platform_bus_probe(struct device_node *root,
         return rc;
 }
 EXPORT_SYMBOL(of_platform_bus_probe);
+
+/**
+ * of_platform_populate() - Populate platform_devices from device tree data
+ * @root: parent of the first level to probe or NULL for the root of the tree
+ * @matches: match table, NULL to use the default
+ * @parent: parent to hook devices from, NULL for toplevel
+ *
+ * Similar to of_platform_bus_probe(), this function walks the device tree
+ * and creates devices from nodes.  It differs in that it follows the modern
+ * convention of requiring all device nodes to have a 'compatible' property,
+ * and it is suitable for creating devices which are children of the root
+ * node (of_platform_bus_probe will only create children of the root which
+ * are selected by the @matches argument).
+ *
+ * New board support should be using this function instead of
+ * of_platform_bus_probe().
+ *
+ * Returns 0 on success, < 0 on failure.
+ */
+int of_platform_populate(struct device_node *root,
+                        const struct of_device_id *matches,
+                        struct device *parent)
+{
+        struct device_node *child;
+        int rc = 0;
+
+        root = root ? of_node_get(root) : of_find_node_by_path("/");
+        if (!root)
+                return -EINVAL;
+
+        for_each_child_of_node(root, child) {
+                rc = of_platform_bus_create(child, matches, parent, true);
+                if (rc)
+                        break;
+        }
+
+        of_node_put(root);
+        return rc;
+}
 #endif /* !CONFIG_SPARC */
diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
index 8f023f889a8a..839023351176 100644
--- a/include/linux/of_platform.h
+++ b/include/linux/of_platform.h
@@ -57,6 +57,9 @@ extern struct platform_device *of_platform_device_create(struct device_node *np,
 extern int of_platform_bus_probe(struct device_node *root,
                                  const struct of_device_id *matches,
                                  struct device *parent);
+extern int of_platform_populate(struct device_node *root,
+                                const struct of_device_id *matches,
+                                struct device *parent);
 #endif /* !CONFIG_SPARC */
 
 #endif /* CONFIG_OF_DEVICE */