From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932662AbcFJKzN (ORCPT ); Fri, 10 Jun 2016 06:55:13 -0400 Received: from arroyo.ext.ti.com ([198.47.19.12]:54717 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932245AbcFJKzL (ORCPT ); Fri, 10 Jun 2016 06:55:11 -0400 Subject: Re: [PATCH v10 08/14] usb: otg: add OTG/dual-role core To: Sergei Shtylyov , References: <1465376626-30122-1-git-send-email-rogerq@ti.com> <1465376626-30122-9-git-send-email-rogerq@ti.com> <57592060.6060801@ti.com> <2522343c-422f-79e1-af40-eb953bde42f6@cogentembedded.com> <575A9430.6070508@ti.com> CC: , , , , , , , , , , , , , , , From: Roger Quadros Message-ID: <575A9C7C.7020902@ti.com> Date: Fri, 10 Jun 2016 13:54:52 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/06/16 13:44, Sergei Shtylyov wrote: > On 6/10/2016 1:19 PM, Roger Quadros wrote: > >>>> It provides APIs for the following tasks >>>> >>>> - Registering an OTG/dual-role capable controller >>>> - Registering Host and Gadget controllers to OTG core >>>> - Providing inputs to and kicking the OTG state machine >>>> >>>> Provide a dual-role device (DRD) state machine. >>>> DRD mode is a reduced functionality OTG mode. In this mode >>>> we don't support SRP, HNP and dynamic role-swap. >>>> >>>> In DRD operation, the controller mode (Host or Peripheral) >>>> is decided based on the ID pin status. Once a cable plug (Type-A >>>> or Type-B) is attached the controller selects the state >>>> and doesn't change till the cable in unplugged and a different >>>> cable type is inserted. >>>> >>>> As we don't need most of the complex OTG states and OTG timers >>>> we implement a lean DRD state machine in usb-otg.c. >>>> The DRD state machine is only interested in 2 hardware inputs >>>> 'id' and 'b_sess_vld'. >>>> >>>> Signed-off-by: Roger Quadros >>> >> >> >> >>> [...] >>>> +/** >>>> + * usb_otg_register_gadget - Register the gadget controller to OTG core >>>> + * @gadget: gadget controller >>> >>> We call that USB device controller (UDC). I'm not sure what you meant here... >>> And what about the 2nd arg, 'ops'? >> >> There are 2 data structures representing the Device controller. >> >> struct usb_gadget - represents a usb slave device >> struct usb_udc -struct usb_udc - describes one usb device controller >> >> usb_udc is for private use only. usb_otg_register_gadget() takes struct usb_gadget >> as argument. >> >> Do you want me to refer to struct usb_gadget as UDC? > > No. > >> What is wrong with calling it gadget controller? > > It's not a controller, it's a piece of software AFAIU. Or is my English just too weak? :-) Everything at this point is a piece of software :). struct usb_gadget, represents the gadget controller device not the driver (or software). struct usb_gadget_driver represents the gadget function driver. struct usb_gadget_ops represents the UDC driver ops. -- cheers, -roger