USB: gadget core: Issue ->disconnect() callback from usb_gadget_disconnect()

The gadget documentation doesn't state clearly whether a gadget
driver's ->disconnect() callback should be invoked when the D+ pullup
is turned off.  Some UDC drivers do this and some don't.  This patch
settles the issue by making the core function usb_gadget_disconnect()
issue the callback, so that UDC drivers don't need to worry about it.

A description of the new behavior is added to the function's
kerneldoc.  Also, the patch removes a few superseded callbacks from
other core routines.

Future patches will remove the ->disconnect() calls from the UDC
drivers that make them, as they are now unnecessary.  Until all those
patches are merged gadget drivers may receive extra ->disconnect()
callbacks, but this should be harmless.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index af88b48c1cea9f5cbb1c756df6602a8bba25a815..87d6b12779f2e94129657f2047a9e030176e2825 100644 (file)
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -690,6 +690,9 @@ EXPORT_SYMBOL_GPL(usb_gadget_connect);
  * as a disconnect (when a VBUS session is active).  Not all systems
  * support software pullup controls.
  *
+ * Following a successful disconnect, invoke the ->disconnect() callback
+ * for the current gadget driver so that UDC drivers don't need to.
+ *
  * Returns zero on success, else negative errno.
  */
 int usb_gadget_disconnect(struct usb_gadget *gadget)
@@ -711,8 +714,10 @@ int usb_gadget_disconnect(struct usb_gadget *gadget)
        }
 
        ret = gadget->ops->pullup(gadget, 0);
-       if (!ret)
+       if (!ret) {
                gadget->connected = 0;
+               gadget->udc->driver->disconnect(gadget);
+       }
 
 out:
        trace_usb_gadget_disconnect(gadget, ret);
@@ -1281,7 +1286,6 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
        kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 
        usb_gadget_disconnect(udc->gadget);
-       udc->driver->disconnect(udc->gadget);
        udc->driver->unbind(udc->gadget);
        usb_gadget_udc_stop(udc);
 
@@ -1471,7 +1475,6 @@ static ssize_t soft_connect_store(struct device *dev,
                usb_gadget_connect(udc->gadget);
        } else if (sysfs_streq(buf, "disconnect")) {
                usb_gadget_disconnect(udc->gadget);
-               udc->driver->disconnect(udc->gadget);
                usb_gadget_udc_stop(udc);
        } else {
                dev_err(dev, "unsupported command '%s'\n", buf);