From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5DA5BC004C9 for ; Tue, 7 May 2019 09:39:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 279AB206A3 for ; Tue, 7 May 2019 09:39:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557221987; bh=oXRKVHlZHDamJiPpfj36vVQjP9gWgXkIVXvvUy/gBho=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=o85kHN6bwVFXE0RG2TwobFmsHzTJw6tBVp5DXVAYJKe55qBxt2MnJWb8tORICpF0K tE8TWAEXwdHn371rB4WSMSD6U2u44Vfj7wBCqQWqOVqdRX2nwiMi6P2hpinZaieKjP Fh3wDahAihcatCd1PzGJruM5AzGFLnF/jkJ4WsqA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726922AbfEGJjp (ORCPT ); Tue, 7 May 2019 05:39:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:59076 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726399AbfEGJjp (ORCPT ); Tue, 7 May 2019 05:39:45 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 94DA820675; Tue, 7 May 2019 09:39:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557221984; bh=oXRKVHlZHDamJiPpfj36vVQjP9gWgXkIVXvvUy/gBho=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qPEBnk56bPCyo9NFwqkasLn5N18ZRBOfXBTZNk8ltq1OK5Wc3wNOJmcvU/wc2KnBP 8a8ouUroyRoxPFWe5QgaWTyQ1P/vt46oTvnNewYaCKmZYWr5lIDRSdXENo5iaMS1o8 WMQOmbEcR9CbwtLCmbgbkdwzCTMDtvUqL2Uvr750= Date: Tue, 7 May 2019 11:39:41 +0200 From: Greg KH To: Dragan Cvetic Cc: "arnd@arndb.de" , Michal Simek , "linux-arm-kernel@lists.infradead.org" , "robh+dt@kernel.org" , "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Derek Kiernan Subject: Re: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver Message-ID: <20190507093941.GC20355@kroah.com> References: <1556402706-176271-1-git-send-email-dragan.cvetic@xilinx.com> <1556402706-176271-3-git-send-email-dragan.cvetic@xilinx.com> <20190502172007.GA1874@kroah.com> <20190504075502.GA11133@kroah.com> <20190506123425.GA26360@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 07, 2019 at 08:48:41AM +0000, Dragan Cvetic wrote: > > > > -----Original Message----- > > From: Greg KH [mailto:gregkh@linuxfoundation.org] > > Sent: Monday 6 May 2019 13:34 > > To: Dragan Cvetic > > Cc: arnd@arndb.de; Michal Simek ; linux-arm-kernel@lists.infradead.org; robh+dt@kernel.org; > > mark.rutland@arm.com; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Derek Kiernan > > Subject: Re: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver > > > > On Mon, May 06, 2019 at 12:23:56PM +0000, Dragan Cvetic wrote: > > > > > > > > > > -----Original Message----- > > > > From: Greg KH [mailto:gregkh@linuxfoundation.org] > > > > Sent: Saturday 4 May 2019 08:55 > > > > To: Dragan Cvetic > > > > Cc: arnd@arndb.de; Michal Simek ; linux-arm-kernel@lists.infradead.org; robh+dt@kernel.org; > > > > mark.rutland@arm.com; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Derek Kiernan > > > > Subject: Re: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver > > > > > > > > On Fri, May 03, 2019 at 04:41:21PM +0000, Dragan Cvetic wrote: > > > > > Hi Greg, > > > > > > > > > > Please find my inline comments below, > > > > > > > > > > Regards > > > > > Dragan > > > > > > > > > > > -----Original Message----- > > > > > > From: Greg KH [mailto:gregkh@linuxfoundation.org] > > > > > > Sent: Thursday 2 May 2019 18:20 > > > > > > To: Dragan Cvetic > > > > > > Cc: arnd@arndb.de; Michal Simek ; linux-arm-kernel@lists.infradead.org; robh+dt@kernel.org; > > > > > > mark.rutland@arm.com; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Derek Kiernan > > > > > > Subject: Re: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver > > > > > > > > > > > > On Sat, Apr 27, 2019 at 11:04:56PM +0100, Dragan Cvetic wrote: > > > > > > > +#define DRIVER_NAME "xilinx_sdfec" > > > > > > > +#define DRIVER_VERSION "0.3" > > > > > > > > > > > > Version means nothing with the driver in the kernel tree, please remove > > > > > > it. > > > > > > > > > > Will be removed. Thank you. > > > > > > > > > > > > > > > > > > +#define DRIVER_MAX_DEV BIT(MINORBITS) > > > > > > > > > > > > Why this number? Why limit yourself to any number? > > > > > > > > > > > > > > > > There can be max 8 devices for this driver. I'll change to 8. > > > > > > > > > > > > + > > > > > > > +static struct class *xsdfec_class; > > > > > > > > > > > > Do you really need your own class? > > > > > > > > > > When writing a character device driver, my goal is to create and register an instance > > > > > of that structure associated with a struct file_operations, exposing a set of operations > > > > > to the user-space. One of the steps to make this goal is Create a class for a devices, > > > > > visible in /sys/class/. > > > > > > > > Why do you need a class? Again, why not just use the misc_device api, > > > > that seems much more relevant here and will make the code a lot simpler. > > > > > > > > > > The driver can have 8 devices in SoC plus more in Programming Logic. > > > It looked logical to group them under the same MAJOR, although they > > > are independent of each other. Is this argument strong enough to use > > > class? > > > > Not really :) > > > > 8 devices is pretty small. What tool will be trying to talk to all of > > these devices and how was it going to find out what devices were in the > > system? > > > > These devices are Forward Error Correction encoder/decoder > and will be part of the RF communication chain. They will be included > in the system through DT. Also, described in DT. Userspace doesn't mess with DT. I am asking what userspace tool/program is going to be interacting with these devices through your now-custom api you are creating. Do you have a link to that software, and how is that code doing the "determine what device nodes are associated with what devices" logic? thanks, greg k-h