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 <[email protected]>
---
drivers/usb/gadget/udc/core.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index d59f94464b87..876b8635b16f 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);
base-commit: 67be068d31d423b857ffd8c34dbcc093f8dfff76
--
2.44.0.278.ge034bb2e1d-goog