Re: [PATCH v2 2/3] ARM: dts: sunxi: add support for Orange Pi Zero board

From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Icenowy Zheng <icenowy@aosc.xyz>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"Vishnu Patekar" <vishnupatekar0510@gmail.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"André Przywara" <andre.przywara@arm.com>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"Russell King" <linux@armlinux.org.uk>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Hans de Goede" <hdegoede@redhat.com>,
	"Chen-Yu Tsai" <wens@csie.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 2/3] ARM: dts: sunxi: add support for Orange Pi Zero board
Date: Mon, 5 Dec 2016 09:52:55 +0100	[thread overview]
Message-ID: <20161205085255.ij3du3if2ss3q3h5@lukather> (raw)
In-Reply-To: <11498641480688550@web2g.yandex.ru>

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On Fri, Dec 02, 2016 at 10:22:30PM +0800, Icenowy Zheng wrote:
> 
> 
> 01.12.2016, 17:36, "Maxime Ripard" <maxime.ripard@free-electrons.com>:
> > On Mon, Nov 28, 2016 at 12:29:07AM +0000, André Przywara wrote:
> >>  > Something more interesting happened.
> >>  >
> >>  > Xunlong made a add-on board for Orange Pi Zero, which exposes the
> >>  > two USB Controllers exported at expansion bus as USB Type-A
> >>  > connectors.
> >>  >
> >>  > Also it exposes a analog A/V jack and a microphone.
> >>  >
> >>  > Should I enable {e,o}hci{2.3} in the device tree?
> >>
> >>  Actually we should do this regardless of this extension board. The USB
> >>  pins are not multiplexed and are exposed on user accessible pins (just
> >>  not soldered, but that's a detail), so I think they qualify for DT
> >>  enablement. And even if a user can't use them, it doesn't hurt to have
> >>  them (since they are not multiplexed).
> >
> > My main concern about this is that we'll leave regulators enabled by
> > default, for a minority of users. And that minority will prevent to do
> > a proper power management when the times come since we'll have to keep
> > that behaviour forever.
> 
> I think these users can add a 'fdt set /xxx/xxx status "disabled" ' .

You can't ask that from the majority of users. These users will take
debian or fedora, install it, and expect everything to work
properly. I would make the opposite argument actually. If someone is
knowledgeable enough to solder the USB pins a connector, then (s)he'll
be able to make that u-boot call.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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