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: <20180718235710.18242-1-jmkrzyszt@gmail.com> <20180806222918.12644-1-jmkrzyszt@gmail.com>
 <20180806222918.12644-5-jmkrzyszt@gmail.com>
In-Reply-To: <20180806222918.12644-5-jmkrzyszt@gmail.com>
From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Fri, 10 Aug 2018 12:11:19 +0200
Message-ID: <CACRpkdZFq3AfH6ehCzMYqwptyfpdd3NLurx3kgj==DmKRASuiA@mail.gmail.com>
Subject: Re: [RFC PATCH v2 04/12] mtd: rawnand: ams-delta: request data port
 GPIO resource
To:     Janusz Krzysztofik <jmkrzyszt@gmail.com>
Cc:     Boris Brezillon <boris.brezillon@bootlin.com>,
        Jonathan Corbet <corbet@lwn.net>,
        =?UTF-8?Q?Miqu=C3=A8l_Raynal?= <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Mark Vasut <marek.vasut@gmail.com>,
        ext Tony Lindgren <tony@atomide.com>,
        Aaro Koskinen <aaro.koskinen@iki.fi>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux-OMAP <linux-omap@vger.kernel.org>,
        linux-mtd@lists.infradead.org, linux-doc@vger.kernel.org,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Aug 7, 2018 at 12:29 AM Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:

> Data port used by the driver is actually an OMAP MPUIO device, already
> under control of gpio-omap driver.  For that reason we used to not
> request the memory region of the port as that would fail because the
> region is already busy.  Despite that, we are still accessing the port
> by just ioremapping it and performing read/write operations.  Moreover,
> we are doing that without any proteciton from other users legally
> manipulating the port pins over GPIO API.
>
> The plan is to convert the driver to access the port over functions
> exposed by the gpio-omap driver.  Before that happens, already prevent
> from other users accessing the port pins by requesting an array of its
> GPIO descriptors.
>
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij