Commit 0ef40f39 authored by Roy Luo's avatar Roy Luo Committed by Greg Kroah-Hartman
Browse files

USB: gadget: core: create sysfs link between udc and gadget 



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: default avatarRoy Luo <royluo@google.com>
Link: https://lore.kernel.org/r/20240307030922.3573161-1-royluo@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2f550553

drivers/usb/gadget/udc/core.c

+9 −0
Original line number Diff line number Diff line
@@ -1424,8 +1424,16 @@ 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);
@@ -1534,6 +1542,7 @@ 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);