From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11616C76190 for ; Mon, 22 Jul 2019 11:56:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E918A20449 for ; Mon, 22 Jul 2019 11:56:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730088AbfGVL4t (ORCPT ); Mon, 22 Jul 2019 07:56:49 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:43020 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727507AbfGVL4t (ORCPT ); Mon, 22 Jul 2019 07:56:49 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 828CF80342; Mon, 22 Jul 2019 13:56:35 +0200 (CEST) Date: Mon, 22 Jul 2019 13:56:45 +0200 From: Pavel Machek To: "gregkh@linuxfoundation.org" Cc: Pawel Laszczak , "felipe.balbi@linux.intel.com" , "linux-usb@vger.kernel.org" , "rogerq@ti.com" , "linux-kernel@vger.kernel.org" , "jbergsagel@ti.com" , "nsekhar@ti.com" , "nm@ti.com" , Suresh Punnoose , Jayshri Dajiram Pawar , Rahul Kumar , Anil Joy Varughese Subject: Re: [PATCH v10 0/6] Introduced new Cadence USBSS DRD Driver. Message-ID: <20190722115644.GA12069@amd> References: <1563733939-21214-1-git-send-email-pawell@cadence.com> <20190721190335.GA19831@xo-6d-61-c0.localdomain> <20190722114839.GA10515@kroah.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="OXfL5xGRrasGEqWY" Content-Disposition: inline In-Reply-To: <20190722114839.GA10515@kroah.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org --OXfL5xGRrasGEqWY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > >> This patch introduce new Cadence USBSS DRD driver to linux kernel. > > >> > > >> The Cadence USBSS DRD Controller is a highly configurable IP Core wh= ich > > >> can be instantiated as Dual-Role Device (DRD), Peripheral Only and > > >> Host Only (XHCI)configurations. > > > > > >I see you are using debugfs to select between DRD, peripheral-onlyh an= d XHCI... > > > > > >Is that good idea? > >=20 > > Yes driver allows selecting dr_mode by debugfs. Controller also support= such functionality=20 > > so I don't understand why would it not be a good idea.=20 > >=20 > > I personally use this for testing but it can be used to limit controlle= r functionality without=20 > > recompiling kernel.=20 >=20 > debugfs is ONLY for debugging, never rely on it being enabled, or > mounted, on a system in order to have any normal operation happen. >=20 > So for testing, yes, this is fine. If this is going to be the normal > api/interface for how to control this driver, no, that is not acceptable > at all. It makes a lot of sense for end-user to toggle this... for example when he is lacking right cable for proper otg detection. As it is third driver offering this functionality, I believe we should stop treating it as debugging. Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --OXfL5xGRrasGEqWY Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl01pHwACgkQMOfwapXb+vIDNQCgwTTLQIqZhxOPwF0uWn3pcLMd 9qQAnjloOlNoULIYu4F5WNb9967eMecO =BZoL -----END PGP SIGNATURE----- --OXfL5xGRrasGEqWY--