From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srinivas Kandagatla Subject: Re: [PATCH RFC] eeprom: at24: extend driver to plug into the NVMEM framework Date: Mon, 17 Aug 2015 15:59:23 +0100 Message-ID: <55D1F6CB.2010606@linaro.org> References: <1439693649-10809-1-git-send-email-andrew@lunn.ch> <2080648987.23864.1439713686409.JavaMail.open-xchange@oxbsltgw04.schlund.de> <20150816131130.GC10094@lunn.ch> <1511754934.28154.1439739426390.JavaMail.open-xchange@oxbsltgw00.schlund.de> <55D1DB24.8090602@linaro.org> <20150817130945.GE7537@lunn.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150817130945.GE7537-g2DYL2Zd6BY@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Andrew Lunn Cc: Stefan Wahren , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org, Maxime Ripard List-Id: linux-i2c@vger.kernel.org On 17/08/15 14:09, Andrew Lunn wrote: > On Mon, Aug 17, 2015 at 02:01:24PM +0100, Srinivas Kandagatla wrote: >> >> +Adding Maxime in the loop >> >> On 16/08/15 16:37, Stefan Wahren wrote: >>>>> Another question which spring to mind is, do we want the eeprom to be >>>>> in /sys twice, the old and the new way? Backwards compatibility says >>>>> the old must stay. Do we want a way to suppress the new? Or should we >>>>> be going as far as refractoring the code into a core library, and two >>>>> wrapper drivers, old and new? >>> I think these are questions for the framework maintainers. >>> >> One of the reasons for the NVMEM framework is to remove that >> duplicate code in the every driver. There was no framework/ABI >> which was guiding such old eeprom sysfs entry in first place, so I >> dont see an issue in removing it for good. Correct me if am wrong. > > The reason for keeping it is backwards compatibility. Having the > contents of the EEPROM as a file in /sys via this driver is now a part > of the Linux ABI. You cannot argue it is not an ABI, just because > there is no framework. Userspace will be assuming it exists at the > specified location. So we cannot remove it, for existing uses of the > driver. Am Ok as long as someone is happy to maintain it. --srini > > However, for new uses of this driver, it is O.K. to only have the > NVMEM file. > > Andrew > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755429AbbHQO71 (ORCPT ); Mon, 17 Aug 2015 10:59:27 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:38799 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750892AbbHQO70 (ORCPT ); Mon, 17 Aug 2015 10:59:26 -0400 Message-ID: <55D1F6CB.2010606@linaro.org> Date: Mon, 17 Aug 2015 15:59:23 +0100 From: Srinivas Kandagatla User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Andrew Lunn CC: Stefan Wahren , linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, wsa@the-dreams.de, Maxime Ripard Subject: Re: [PATCH RFC] eeprom: at24: extend driver to plug into the NVMEM framework References: <1439693649-10809-1-git-send-email-andrew@lunn.ch> <2080648987.23864.1439713686409.JavaMail.open-xchange@oxbsltgw04.schlund.de> <20150816131130.GC10094@lunn.ch> <1511754934.28154.1439739426390.JavaMail.open-xchange@oxbsltgw00.schlund.de> <55D1DB24.8090602@linaro.org> <20150817130945.GE7537@lunn.ch> In-Reply-To: <20150817130945.GE7537@lunn.ch> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/08/15 14:09, Andrew Lunn wrote: > On Mon, Aug 17, 2015 at 02:01:24PM +0100, Srinivas Kandagatla wrote: >> >> +Adding Maxime in the loop >> >> On 16/08/15 16:37, Stefan Wahren wrote: >>>>> Another question which spring to mind is, do we want the eeprom to be >>>>> in /sys twice, the old and the new way? Backwards compatibility says >>>>> the old must stay. Do we want a way to suppress the new? Or should we >>>>> be going as far as refractoring the code into a core library, and two >>>>> wrapper drivers, old and new? >>> I think these are questions for the framework maintainers. >>> >> One of the reasons for the NVMEM framework is to remove that >> duplicate code in the every driver. There was no framework/ABI >> which was guiding such old eeprom sysfs entry in first place, so I >> dont see an issue in removing it for good. Correct me if am wrong. > > The reason for keeping it is backwards compatibility. Having the > contents of the EEPROM as a file in /sys via this driver is now a part > of the Linux ABI. You cannot argue it is not an ABI, just because > there is no framework. Userspace will be assuming it exists at the > specified location. So we cannot remove it, for existing uses of the > driver. Am Ok as long as someone is happy to maintain it. --srini > > However, for new uses of this driver, it is O.K. to only have the > NVMEM file. > > Andrew >