Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20180813214924.3567840-1-arnd@arndb.de> <Pine.LNX.4.44L0.1808140957350.1466-100000@iolanthe.rowland.org>
 <CAK8P3a33DRBj6ZeJBeWGnw3RnpK3rTaYtrbs6jjZ8VVPOk8=qw@mail.gmail.com> <OSBPR01MB22931014287A7641FFBFBE56D8320@OSBPR01MB2293.jpnprd01.prod.outlook.com>
In-Reply-To: <OSBPR01MB22931014287A7641FFBFBE56D8320@OSBPR01MB2293.jpnprd01.prod.outlook.com>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 20 Aug 2018 13:22:16 +0200
Message-ID: <CAK8P3a1eWyqp=fevH2KvbhTgRGXFXgtXpfObkEqLO2c5x6WNvA@mail.gmail.com>
Subject: Re: [PATCH] usb: hide usb_of_get_companion_dev for CONFIG_USB=n
To:     yoshihiro.shimoda.uh@renesas.com
Cc:     Alan Stern <stern@rowland.harvard.edu>,
        gregkh <gregkh@linuxfoundation.org>,
        Felipe Balbi <balbi@kernel.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Johan Hovold <johan@kernel.org>,
        USB list <linux-usb@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Aug 20, 2018 at 5:22 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@renesas.com> wrote:
> > From: Arnd Bergmann, Sent: Tuesday, August 14, 2018 11:27 PM
> >
> > On Tue, Aug 14, 2018 at 3:58 PM Alan Stern <stern@rowland.harvard.edu> wrote:
> > > On Mon, 13 Aug 2018, Arnd Bergmann wrote:
> > > > diff --git a/drivers/usb/gadget/udc/Kconfig b/drivers/usb/gadget/udc/Kconfig
> > > > index 0a16cbd4e528..663a8bd67a7b 100644
> > > > --- a/drivers/usb/gadget/udc/Kconfig
> > > > +++ b/drivers/usb/gadget/udc/Kconfig
> > > > @@ -193,6 +193,7 @@ config USB_RENESAS_USB3
> > > >       tristate 'Renesas USB3.0 Peripheral controller'
> > > >       depends on ARCH_RENESAS || COMPILE_TEST
> > > >       depends on EXTCON
> > > > +     depends on USB || !USB
> > >
> > > Is this some weird standard idiom?  It looks really strange.
> >
> > Yes, and yes.
> >
> > A less common way to write it is
> >
> >         depends on (USB != m) || m
> >
> > which some people prefer, but I find even weirder.
>
> Thank you for the patch!
>
> On other thread, John mentions gadget-side drivers should not depend on host-side [1].
> So, I submitted a patch today [2]. What do you think about my submitted patch?
>
> [1]
> https://marc.info/?l=linux-usb&m=153433776202861&w=2

I don't really think this is a big issue, as you can still build the driver
with CONFIG_USB=n, so it's not a strict dependency.

> [2]
> https://patchwork.kernel.org/patch/10569847/

On the other hand, your patch looks nice and is somewhat
less confusing, so you have my Ack on that.

      Arnd