From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760720Ab3DBMvo (ORCPT ); Tue, 2 Apr 2013 08:51:44 -0400 Received: from mail.active-venture.com ([67.228.131.205]:56928 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759896Ab3DBMvn (ORCPT ); Tue, 2 Apr 2013 08:51:43 -0400 X-Originating-IP: 108.223.40.66 Date: Tue, 2 Apr 2013 05:51:49 -0700 From: Guenter Roeck To: Pavel Machek Cc: sr@denx.de, w.sang@pengutronix.de, magnus.damm@gmail.com, hjk@linutronix.de, Greg KH , linux-kernel@vger.kernel.org, dzu@denx.de Subject: Re: UIO device tree bindings. Message-ID: <20130402125149.GA7216@roeck-us.net> References: <20130401142336.GA18034@amd.pavel.ucw.cz> <20130401154008.GA20963@amd.pavel.ucw.cz> <20130402024212.GA19431@roeck-us.net> <20130402115151.GA9052@amd.pavel.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130402115151.GA9052@amd.pavel.ucw.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 02, 2013 at 01:51:51PM +0200, Pavel Machek wrote: > On Mon 2013-04-01 19:42:12, Guenter Roeck wrote: > > On Mon, Apr 01, 2013 at 05:40:08PM +0200, Pavel Machek wrote: > > > On Mon 2013-04-01 16:23:36, Pavel Machek wrote: > > > > Hi! > > > > > > > > I'd like to get uio device tree bindings to work -- with recent FPGA > > > > parts it will be important. Latest version I see is > > > > > > > > https://lists.ozlabs.org/pipermail/linuxppc-dev/2009-June/073087.html > > > > > > > > ... Is there anything newer? > > > > > > > > I red the discussion, and main problem seems to be the "tell kernel to > > > > drive this device tree device", right? > > > > > Problem seems to be the notion that the proposed devicetree entry would not > > describe the hardware, but its use. Not really sure I understand the problem, > > as I would see the hardware description to be "A hardware device which is > > compatible to and managed by the generic-uio driver". I would argue that > > this _is_ a hardware description (if not, what is ?), but I am not the one > > to make the call. > > Well... one could argue that having "generic-uio" in board's device > tree _is_ wrong, but having driver that binds to "generic-uio" is > not. Hmm? > You mean like "ata-generic" ? > Or maybe we can do some magic with module parameter. That should be > enough for expected use. > I don't think that would make a difference. I mean, just take ns16550 as another example. No one has problems declaring some block of hardware addresses to be compatible with "ns16550", even though it can be anything including a memory block on one of the FPGAs or ASICs we are talking about here, it can be anything but a NS16550, and many of the actual "compatible" strings are not defined anythere either. So there is no problem with "ata-generic" and "ns16550", and no one cares if "fsl,mpc8349emitx-pata" or "xlnx,xps-uart16550-2.00.b" is defined or not, but "generic-uio" together with "ptx,c64fpga001" is unacceptable. I think it has more to do with the uio driver not being an actual driver, but the kernel part of a user-space driver, though that is just a wild guess. Guenter