From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Simek Subject: Re: [PATCH] uio/pdrv_genirq: Add OF support Date: Thu, 31 Mar 2011 19:57:47 +0200 Message-ID: <4D94C09B.4070506@monstr.eu> References: <1301574600-4861-1-git-send-email-monstr@monstr.eu> <1301574600-4861-2-git-send-email-monstr@monstr.eu> <20110331124925.GA2202@pengutronix.de> <4D948189.9070606@monstr.eu> <20110331170321.GA2734@local> Reply-To: monstr@monstr.eu Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110331170321.GA2734@local> Sender: linux-kernel-owner@vger.kernel.org To: "Hans J. Koch" Cc: Wolfram Sang , devicetree-discuss@lists.ozlabs.org, grant.likely@secretlab.ca, john.williams@petalogix.com, linux-kernel@vger.kernel.org, hjk@linutronix.de, gregkh@suse.de List-Id: devicetree@vger.kernel.org Hans J. Koch wrote: > On Thu, Mar 31, 2011 at 03:28:41PM +0200, Michal Simek wrote: >>>> + uioinfo->name = pdev->dev.of_node->name; >>>> + /* Use version for storing full IP name for identification */ >>>> + uioinfo->version = pdev->dev.of_node->full_name; >>> I don't think this is apropriate, but will leave that to Hans. >> I was thinking what to add and I choose full_name because I can read >> this value and identify which UIO is this device. >> I know that there should be version but there is no version string in DTS. > > The purpose of uio_info->version is to give the userspace part of the driver > additional information. Kernel part and userspace part might be developed > independently, and there should be a chance for the userspace part to find > out if a certain feature is already supported by the kernel part without > having to do dirty kernel version checks. > > So, uio_info->version is an information about the driver, not the hardware. > > Example: You write a UIO driver for a chip you use in a project. You don't > need all the functionality of that chip. One year later you need additional > chip functionality, and it turns out that you have to do certain > initializations in the kernel part. Your new userspace will need the new > kernel driver, but there are lots of older kernels around in your customers > devices. In that case, your userspace part can simply check the version > string in sysfs and require at least your new version. I understand reasons but this information is not in device tree and it must be setup. Grant suggested compatible string but it is not the best option too. > >>>> + /* Get IRQ for the device */ >>>> + rc = of_irq_to_resource(pdev->dev.of_node, 0, &r_irq); >>>> + if (rc == NO_IRQ) >>>> + dev_err(&pdev->dev, "no IRQ found\n"); >>> No error, I think. Sometimes just mmaping the registers is enough. >> OK. Let's changed it to dev_info if you like. > > The correct thing is to set uio_info->irq to UIO_IRQ_NONE. ok, done. Michal -- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/ Microblaze U-BOOT custodian