This is a note to let you know that I've just added the patch titled
USB: gadget: core: create sysfs link between udc and gadget
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-gadget-core-create-sysfs-link-between-udc-and-ga.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b1e7b4ac6d8af9f53e3cc4beb2bea5f38caf86ed
Author: Roy Luo <royluo@xxxxxxxxxx>
Date: Thu Mar 7 03:09:22 2024 +0000
USB: gadget: core: create sysfs link between udc and gadget
[ Upstream commit 0ef40f399aa2be8c04aee9b7430705612c104ce5 ]
udc device and gadget device are tightly coupled, yet there's no good
way to corelate the two. Add a sysfs link in udc that points to the
corresponding gadget device.
An example use case: userspace configures a f_midi configfs driver and
bind the udc device, then it tries to locate the corresponding midi
device, which is a child device of the gadget device. The gadget device
that's associated to the udc device has to be identified in order to
index the midi device. Having a sysfs link would make things much
easier.
Signed-off-by: Roy Luo <royluo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240307030922.3573161-1-royluo@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Stable-dep-of: 399a45e5237c ("usb: gadget: core: flush gadget workqueue after device removal")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 6d7f8e98ba2a8..5085580eeb3ad 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -1419,8 +1419,16 @@ int usb_add_gadget(struct usb_gadget *gadget)
if (ret)
goto err_free_id;
+ ret = sysfs_create_link(&udc->dev.kobj,
+ &gadget->dev.kobj, "gadget");
+ if (ret)
+ goto err_del_gadget;
+
return 0;
+ err_del_gadget:
+ device_del(&gadget->dev);
+
err_free_id:
ida_free(&gadget_id_numbers, gadget->id_number);
@@ -1529,6 +1537,7 @@ void usb_del_gadget(struct usb_gadget *gadget)
mutex_unlock(&udc_lock);
kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
+ sysfs_remove_link(&udc->dev.kobj, "gadget");
flush_work(&gadget->work);
device_del(&gadget->dev);
ida_free(&gadget_id_numbers, gadget->id_number);
