[4/6] usb: gadget: add functions to signal udc driver to delay status stage

[Bin Liu <b-liu@ti.com>]

Hi,

On Tue, Oct 09, 2018 at 10:49:01PM -0400, Paul Elder wrote:
> A usb gadget function driver may or may not want to delay the status
> stage of a control OUT request. An instance it might want to is to
> asynchronously validate the data of a class-specific request.
> 
> Add a function usb_ep_delay_status to allow function drivers to choose
> to delay the status stage in the request completion handler. The UDC
> should then check the usb_ep->delayed_status flag and act accordingly to
> delay the status stage.
> 
> Also add a function usb_ep_send_response as a wrapper for
> usb_ep->ops->send_response, whose prototype is added as well. This
> function should be called by function drivers to tell the UDC what to
> reply in the status stage that it has requested to be delayed.
> 
> Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/usb/gadget/udc/core.c | 35 +++++++++++++++++++++++++++++++++++
>  include/linux/usb/gadget.h    | 11 +++++++++++
>  2 files changed, 46 insertions(+)
> 
> diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
> index af88b48c1cea..1ec5ce6b43cd 100644
> --- a/drivers/usb/gadget/udc/core.c
> +++ b/drivers/usb/gadget/udc/core.c
> @@ -443,6 +443,41 @@ void usb_ep_fifo_flush(struct usb_ep *ep)
>  }
>  EXPORT_SYMBOL_GPL(usb_ep_fifo_flush);
>  
> +/**
> + * usb_ep_ep_delay_status - set delay_status flag
> + * @ep: the endpoint whose delay_status flag is being set
> + *
> + * This function instructs the UDC to delay the status stage of a control
> + * request. It can only be called from the request completion handler of a
> + * control request.
> + */
> +void usb_ep_delay_status(struct usb_ep *ep)
> +{
> +	ep->delayed_status = true;
> +}
> +EXPORT_SYMBOL_GPL(usb_ep_delay_status);

Is usb_ep_set_delay_status() better? I thought it implies get/return
action if a verb is missing in the function name.

Regards,
-Bin.