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Date: Thu, 31 Mar 2011 15:23:28 +0200
From: Wolfram Sang <w.sang@pengutronix.de>
To: John Williams <john.williams@petalogix.com>
Cc: Michal Simek <monstr@monstr.eu>, devicetree-discuss@lists.ozlabs.org,
        grant.likely@secretlab.ca, linux-kernel@vger.kernel.org,
        hjk@linutronix.de, gregkh@suse.de
Subject: Re: [PATCH] uio/pdrv_genirq: Add OF support
Message-ID: <20110331132328.GB2202@pengutronix.de>
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>    Maybe I misunderstand you, in my view it is the responsibility of <ven=
dor>
>    to create their DTS files to indicate they want <special-card1> to bin=
d to
>    generic-uio.

Device tree is a OS-neutral hardware description language. "generic-uio"
is neither OS-neutral nor a hardware description. devicetree.org has
more information about this.

>    Our use-case is pretty clear, in FPGA-based systems it is common to cr=
eate
>    arbitrary devices that developers just want to control from userspace,
>    with simple IRQ and IO capabilities (DMA can come later :). =EF=BF=BDT=
hey don't
>    need to bind to other kernel APIs or subsystems, and don't want to inv=
est
>    in one-off kernel drivers that simply will never go upstream.

For that, the new_compatible-file would be suitable, I think.

>    UIO is perfect, and simply tagging the device as generic-uio in the DT=
S is
>    so simple, clean, and elegant.

Simple, yes (I do understand I wrote the first approach ;)) . Elegant,
not really, because it breaks core conventions of the device tree. For
your case it is a very conveniant hack, but it is still a hack.

Regards,

   Wolfram

--=20
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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