>From an arbitrary node in the tree, find the enclosing node that
corresponds to a platform device, as registered by
of_platform_populate().
This can be used to find out what device needs to be probed so the
dependency described by a given node is made available.
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
---
Changes in v2:
- Move the logic for finding a platform device from its firmware node to
of/platform.c as it's not needed for ACPI nodes.
drivers/of/platform.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_platform.h | 1 +
2 files changed, 61 insertions(+)
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index ff27494cda8c..89c5cd513027 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -501,6 +501,66 @@ void of_platform_depopulate(struct device *parent)
}
EXPORT_SYMBOL_GPL(of_platform_depopulate);
+static bool of_is_platform(struct device_node *np)
+{
+ int count;
+
+ count = of_property_count_strings(np, "compatible");
+
+ /* The node has to have a compatible string */
+ if (!count)
+ return false;
+
+ /* But it cannot be just a simple memory-mapped bus */
+ if (count == 1 && of_match_node(of_default_bus_match_table, np))
+ return false;
+
+ /* But AMBA devices aren't platform devices */
+ if (of_device_is_compatible(np, "arm,primecell"))
+ return false;
+
+ /* Node is immediately below root */
+ if (!np->parent || !np->parent->parent)
+ return true;
+
+ /* If it's a node in a simple memory-mapped bus */
+ if (of_match_node(of_default_bus_match_table, np->parent))
+ return true;
+
+ return false;
+}
+
+/**
+ * of_platform_device_find() - Find nearest ancestor that is a platform device
+ * @np: node to find platform device for
+ *
+ * Walks the tree up and finds the closest ancestor that has match data and
+ * either is at the root of the tree or is a child of a simple memory mapped
+ * bus.
+ *
+ * Returns such a device, or NULL if none could be found.
+ */
+struct device *of_platform_device_find(struct device_node *np)
+{
+ struct device_node *target;
+ struct platform_device *pdev;
+
+ of_node_get(np);
+
+ for (target = np;
+ !of_node_is_root(target);
+ target = of_get_next_parent(target))
+ if (of_is_platform(target))
+ break;
+
+ pdev = of_find_device_by_node(target);
+
+ of_node_put(target);
+
+ return pdev ? &pdev->dev : NULL;
+}
+EXPORT_SYMBOL_GPL(of_platform_device_find);
+
#ifdef CONFIG_OF_DYNAMIC
static int of_platform_notify(struct notifier_block *nb,
unsigned long action, void *arg)
diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
index 611a691145c4..baefc941fdb8 100644
--- a/include/linux/of_platform.h
+++ b/include/linux/of_platform.h
@@ -58,6 +58,7 @@ extern struct platform_device *of_device_alloc(struct device_node *np,
const char *bus_id,
struct device *parent);
extern struct platform_device *of_find_device_by_node(struct device_node *np);
+extern struct device *of_platform_device_find(struct device_node *np);
/* Platform devices and busses creation */
extern struct platform_device *of_platform_device_create(struct device_node *np,
--
2.4.3
--
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