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Subject[PATCH v1 1/2] driver core: Introduce device_find_first_child() helper
Date
There are several places in the kernel where this kind of functionality is
being used. Provide a generic helper for such cases.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/base/core.c | 24 ++++++++++++++++++++++++
include/linux/device.h | 1 +
2 files changed, 25 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 7cd789c4985d..972bfe975cd0 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3832,6 +3832,30 @@ struct device *device_find_child_by_name(struct device *parent,
}
EXPORT_SYMBOL_GPL(device_find_child_by_name);

+/**
+ * device_find_first_child - device iterator for locating the fist child device.
+ * @parent: parent struct device
+ *
+ * This is similar to the device_find_child() function above, but it
+ * returns a reference to the first child device.
+ *
+ * NOTE: you will need to drop the reference with put_device() after use.
+ */
+struct device *device_find_first_child(struct device *parent)
+{
+ struct klist_iter i;
+ struct device *child;
+
+ if (!parent)
+ return NULL;
+
+ klist_iter_init(&parent->p->klist_children, &i);
+ child = get_device(next_device(&i));
+ klist_iter_exit(&i);
+ return child;
+}
+EXPORT_SYMBOL_GPL(device_find_first_child);
+
int __init devices_init(void)
{
devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
diff --git a/include/linux/device.h b/include/linux/device.h
index dc941997795c..20171a4358df 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -905,6 +905,7 @@ struct device *device_find_child(struct device *dev, void *data,
int (*match)(struct device *dev, void *data));
struct device *device_find_child_by_name(struct device *parent,
const char *name);
+struct device *device_find_first_child(struct device *parent);
int device_rename(struct device *dev, const char *new_name);
int device_move(struct device *dev, struct device *new_parent,
enum dpm_order dpm_order);
--
2.35.1
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