USB: core: add helpers to retrieve endpoints
Many USB drivers iterate over the available endpoints to find required
endpoints of a specific type and direction. Typically the endpoints are
required for proper function and a missing endpoint should abort probe.
To facilitate code reuse, add a helper to retrieve common endpoints
(bulk or interrupt, in or out) and four wrappers to find a single
endpoint.
Note that the helpers are marked as __must_check to serve as a reminder
to always verify that all expected endpoints are indeed present. This
also means that any optional endpoints, typically need to be looked up
through separate calls.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 1487526..7041cc9 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -99,6 +99,41 @@ enum usb_interface_condition {
USB_INTERFACE_UNBINDING,
};
+int __must_check
+usb_find_common_endpoints(struct usb_host_interface *alt,
+ struct usb_endpoint_descriptor **bulk_in,
+ struct usb_endpoint_descriptor **bulk_out,
+ struct usb_endpoint_descriptor **int_in,
+ struct usb_endpoint_descriptor **int_out);
+
+static inline int __must_check
+usb_find_bulk_in_endpoint(struct usb_host_interface *alt,
+ struct usb_endpoint_descriptor **bulk_in)
+{
+ return usb_find_common_endpoints(alt, bulk_in, NULL, NULL, NULL);
+}
+
+static inline int __must_check
+usb_find_bulk_out_endpoint(struct usb_host_interface *alt,
+ struct usb_endpoint_descriptor **bulk_out)
+{
+ return usb_find_common_endpoints(alt, NULL, bulk_out, NULL, NULL);
+}
+
+static inline int __must_check
+usb_find_int_in_endpoint(struct usb_host_interface *alt,
+ struct usb_endpoint_descriptor **int_in)
+{
+ return usb_find_common_endpoints(alt, NULL, NULL, int_in, NULL);
+}
+
+static inline int __must_check
+usb_find_int_out_endpoint(struct usb_host_interface *alt,
+ struct usb_endpoint_descriptor **int_out)
+{
+ return usb_find_common_endpoints(alt, NULL, NULL, NULL, int_out);
+}
+
/**
* struct usb_interface - what usb device drivers talk to
* @altsetting: array of interface structures, one for each alternate