Device tree overlays (the dto files) may contain multiple fragments for
different target nodes. Each fragment contains a __overlay__ node that
is applied to target node specified in the fragment.
Add a helper to call a function for each fragment in a device tree
overlay to avoid having device tree overlay internal information in
other modules.
Signed-off-by: Michael Tretter <m.tretter@xxxxxxxxxxxxxx>
---
Changelog:
v2->v3:
- clarify warning if process fails
- move phandle resolving step to caller
v1->v2:
- add static inline for function stub
---
drivers/of/overlay.c | 38 ++++++++++++++++++++++++++++++++++++++
include/of.h | 13 +++++++++++++
2 files changed, 51 insertions(+)
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index f6a0576183..de79e05cbc 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -194,6 +194,44 @@ static int of_overlay_fixup(struct device_node *root, void *data)
return of_overlay_apply_tree(root, overlay);
}
+/**
+ * Iterate the overlay and call process for each fragment
+ *
+ * If process() fails for any fragment, the function will stop to process
+ * other fragments and return the error of the failed process() call.
+ */
+int of_process_overlay(struct device_node *root,
+ struct device_node *overlay,
+ int (*process)(struct device_node *target,
+ struct device_node *overlay, void *data),
+ void *data)
+{
+ struct device_node *fragment;
+ int err = 0;
+
+ for_each_child_of_node(overlay, fragment) {
+ struct device_node *ovl;
+ struct device_node *target;
+
+ ovl = of_get_child_by_name(fragment, "__overlay__");
+ if (!ovl)
+ continue;
+
+ target = find_target(root, fragment);
+ if (!target)
+ continue;
+
+ err = process(target, ovl, data);
+ if (err) {
+ pr_warn("failed to process overlay for %s\n",
+ target->name);
+ break;
+ }
+ }
+
+ return err;
+}
+
/**
* Register a devicetree overlay
*
diff --git a/include/of.h b/include/of.h
index 1483c22db1..06dc9f61a5 100644
--- a/include/of.h
+++ b/include/of.h
@@ -877,6 +877,11 @@ struct device_node *of_resolve_phandles(struct device_node *root,
int of_overlay_apply_tree(struct device_node *root,
struct device_node *overlay);
int of_register_overlay(struct device_node *overlay);
+int of_process_overlay(struct device_node *root,
+ struct device_node *overlay,
+ int (*process)(struct device_node *target,
+ struct device_node *overlay, void *data),
+ void *data);
#else
static inline struct device_node *of_resolve_phandles(struct device_node *root,
const struct device_node *overlay)
@@ -895,6 +900,14 @@ static inline int of_register_overlay(struct device_node *overlay)
return -ENOSYS;
}
+static inline int of_process_overlay(struct device_node *root,
+ struct device_node *overlay,
+ int (*process)(struct device_node *target,
+ struct device_node *overlay, void *data),
+ void *data)
+{
+ return -ENOSYS;
+}
#endif
#endif /* __OF_H */
--
2.20.1
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