Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753258AbaGKM1x (ORCPT ); Fri, 11 Jul 2014 08:27:53 -0400 Received: from guitar.tcltek.co.il ([192.115.133.116]:47787 "EHLO mx.tkos.co.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752406AbaGKM1v (ORCPT ); Fri, 11 Jul 2014 08:27:51 -0400 Date: Fri, 11 Jul 2014 15:27:44 +0300 From: Baruch Siach To: Linus Walleij Cc: =?iso-8859-1?Q?S=F6ren?= Brinkmann , Mark Rutland , Alexandre Courbot , Harini Katakam , Pawel Moll , "ijc+devicetree@hellion.org.uk" , "linux-doc@vger.kernel.org" , Michal Simek , Harini Katakam , "linux-kernel@vger.kernel.org" , "linux-gpio@vger.kernel.org" , "devicetree@vger.kernel.org" , Rob Herring , Rob Landley , Kumar Gala , Grant Likely , Harini Katakam , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v2 1/2] gpio: Add driver for Zynq GPIO controller Message-ID: <20140711122744.GE3003@tarshish> References: <1403091577-10232-1-git-send-email-harinik@xilinx.com> <5cc8b89b-20ff-4fa9-92dd-bb2f6d3512d8@BY2FFO11FD030.protection.gbl> <20140707152309.GH4939@tarshish> <20140711062811.GC3003@tarshish> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Linus, On Fri, Jul 11, 2014 at 02:06:29PM +0200, Linus Walleij wrote: > On Fri, Jul 11, 2014 at 8:28 AM, Baruch Siach wrote: > > On Tue, Jul 08, 2014 at 11:27:57AM +0200, Linus Walleij wrote: > > >> What is the usecase here? > > > > During boot I need to know, for example, when an FPGA is ready to be > > programmed, and when said FPGA has finished its initialization. I also read > > the sate of on-board DIP switches to determine the desired boot method. I find > > the current sysfs interface quite convenient for these and similar tasks. > > So given that an FPGA is a piece of hardware, it should have its firmware > loaded from the kernel and a kernel driver communicating with it I guess? > > I feel the smell of a huge bundle of userspace drivers for something that > should be handled by the kernel. The FPGA can be loaded using simple SPI bit-banging, for which I used the userspace SPI interface. Nothing fancy, just a few hundred LoC. Kernel driver along with a userspace interface to be maintained forever for this task seems an overkill to me. baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il - -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/