On 20/06/16 10:21, Felipe Balbi wrote:

Hi,

Roger Quadros [off-list ref] writes:

quoted

The OTG core will use struct otg_gadget_ops to
start/stop the gadget controller.

The main purpose of this interface is to avoid directly
calling usb_gadget_start/stop() from the OTG core as they
wouldn't be defined in the built-in symbol table if
CONFIG_USB_GADGET is m.

Signed-off-by: Roger Quadros <redacted>
---
 include/linux/usb/gadget.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 2dd9e6b..f4fc0aa 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h

@@ -639,6 +639,22 @@ struct usb_gadget_driver {
 };
 
 
+/*-------------------------------------------------------------------------*/
+
+/**
+ * struct otg_gadget_ops - Interface between OTG core and gadget
+ *
+ * Provided by the gadget core to allow the OTG core to start/stop the gadget
+ *
+ * @start: function to start the gadget
+ * @stop: function to stop the gadget
+ * @connect_control: function to connect/disconnect from the bus
+ */
+struct otg_gadget_ops {
+	int (*start)(struct usb_gadget *gadget);
+	int (*stop)(struct usb_gadget *gadget);
+	int (*connect_control)(struct usb_gadget *gadget, bool connect);
+};

you shouldn't need these at all. They are already part of the gadget
framework as ->udc_start(), ->udc_stop() and ->pullup()

This is to avoid the undefined symbol errors during build when OTG has is
built-in because USB (host) is built-in but GADGET is still a module.

cheers,
-roger