linux-kernel - Re: [Patch v2 1/2] gpio: add GPIO hogging mechanism

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CACRpkdZcNcPBYQM438CZJx1gYst9BFBSTj-3Qv2aPGF9pdWa5g@mail.gmail.com>
Date:	Tue, 2 Dec 2014 15:29:46 +0100
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Alexandre Courbot <gnurou@...il.com>
Cc:	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Benoit Parrot <bparrot@...com>,
	Pantelis Antoniou <panto@...oniou-consulting.com>,
	Jiri Prchal <jiri.prchal@...ignal.cz>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [Patch v2 1/2] gpio: add GPIO hogging mechanism

On Tue, Dec 2, 2014 at 3:13 PM, Alexandre Courbot <gnurou@...il.com> wrote:
> On Tue, Dec 2, 2014 at 1:36 AM, Maxime Ripard
> <maxime.ripard@...e-electrons.com> wrote:

>> The only thing I'd like to have would be that the request here would
>> be non-exclusive, so that a later driver would still be allowed later
>> on to request that GPIO later on and manage it itself (ideally using
>> the usual gpiod_request function).
>
> Actually we have a plan (and I have some code too) to allow multiple
> consumers per GPIO. Although like Benoit I wonder why you would want
> to hog a GPIO and then request it properly later. Also, that probably
> means we should abandon the hog since it actively drives the line and
> would interfere with the late requested. How to do that correctly is
> not really clear to me.

I don't get the usecase. A hogged GPIO is per definition hogged.
This sounds more like "initial settings" or something, which is another
usecase altogether.

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/