From: Damien Riegel <damien.riegel@savoirfairelinux.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
devicetree@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
kernel@savoirfairelinux.com
Subject: Re: [PATCH 2/2] Input: add touchscreen support for TS-4800
Date: Sun, 13 Dec 2015 15:55:57 -0500 [thread overview]
Message-ID: <20151213205557.GA4600@localhost> (raw)
In-Reply-To: <20151213045858.GB22780@dtor-ws>
Hi Dmitry
On Sat, Dec 12, 2015 at 08:58:58PM -0800, Dmitry Torokhov wrote:
> Hi Damien,
>
> On Thu, Dec 10, 2015 at 11:11:12AM -0500, Damien Riegel wrote:
> > On this board, the touchscreen, an ads7843, is not handled directly by
> > Linux but by a companion FPGA. This FPGA is memory-mapped and the IP
> > design is very similar to the mk712.
>
> ...
>
> > +
> > + poll_dev = devm_input_allocate_polled_device(&pdev->dev);
> > + if (!poll_dev)
> > + return -ENOMEM;
>
> I wonder how useful touchscreen implemented as polling device is. Isn't
> there an interrupt line for it?
There is an interrupt line between the touchscreen and the FGPA, but not
between the FPGA and the SoC. I agree it is a bit peculiar. Hopefully on
more recent boards, they changed their design to handle the touchscreen
directly with Linux.
Thanks,
Damien
> Thanks.
>
> --
> Dmitry
next prev parent reply other threads:[~2015-12-13 20:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-10 16:11 [PATCH 1/2] Input: add touchscreen bindings for TS-4800 Damien Riegel
[not found] ` <1449763872-572-1-git-send-email-damien.riegel-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org>
2015-12-10 16:11 ` [PATCH 2/2] Input: add touchscreen support " Damien Riegel
[not found] ` <1449763872-572-2-git-send-email-damien.riegel-4ysUXcep3aM1wj+D4I0NRVaTQe2KTcn/@public.gmane.org>
2015-12-13 4:58 ` Dmitry Torokhov
2015-12-13 20:55 ` Damien Riegel [this message]
2015-12-17 4:11 ` Dmitry Torokhov
2015-12-11 3:39 ` [PATCH 1/2] Input: add touchscreen bindings " Rob Herring
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