From dad9bb017865ae794b6cdfac40d60b1466a09195 Mon Sep 17 00:00:00 2001 From: Heikki Krogerus Date: Fri, 31 May 2019 17:15:37 +0300 Subject: [PATCH] driver core: Add helper device_find_child_by_name() It looks like the child device is often matched with a name. This introduces a helper that does it automatically. Signed-off-by: Heikki Krogerus Acked-by: Greg Kroah-Hartman Tested-by: Hans de Goede Signed-off-by: Rafael J. Wysocki --- drivers/base/core.c | 28 ++++++++++++++++++++++++++++ include/linux/device.h | 2 ++ 2 files changed, 30 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index fd7511e04e62..b4c64528f13c 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2474,6 +2474,34 @@ struct device *device_find_child(struct device *parent, void *data, } EXPORT_SYMBOL_GPL(device_find_child); +/** + * device_find_child_by_name - device iterator for locating a child device. + * @parent: parent struct device + * @name: name of the child device + * + * This is similar to the device_find_child() function above, but it + * returns a reference to a device that has the name @name. + * + * NOTE: you will need to drop the reference with put_device() after use. + */ +struct device *device_find_child_by_name(struct device *parent, + const char *name) +{ + struct klist_iter i; + struct device *child; + + if (!parent) + return NULL; + + klist_iter_init(&parent->p->klist_children, &i); + while ((child = next_device(&i))) + if (!strcmp(dev_name(child), name) && get_device(child)) + break; + klist_iter_exit(&i); + return child; +} +EXPORT_SYMBOL_GPL(device_find_child_by_name); + 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 e85264fb6616..5489a759e1c5 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1250,6 +1250,8 @@ extern int device_for_each_child_reverse(struct device *dev, void *data, int (*fn)(struct device *dev, void *data)); extern struct device *device_find_child(struct device *dev, void *data, int (*match)(struct device *dev, void *data)); +extern struct device *device_find_child_by_name(struct device *parent, + const char *name); extern int device_rename(struct device *dev, const char *new_name); extern int device_move(struct device *dev, struct device *new_parent, enum dpm_order dpm_order); -- 2.45.2