From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932224AbaFBOa0 (ORCPT ); Mon, 2 Jun 2014 10:30:26 -0400 Received: from mout.gmx.net ([212.227.17.20]:63318 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755013AbaFBO36 (ORCPT ); Mon, 2 Jun 2014 10:29:58 -0400 Message-ID: <538C8A59.2070907@gmx.de> Date: Mon, 02 Jun 2014 16:29:45 +0200 From: Michael Lawnick User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Linus Walleij , Wolfram Sang , Grant Likely CC: Lee Jones , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-i2c@vger.kernel.org" Subject: Re: [PATCH] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices References: <1401452797-29521-1-git-send-email-lee.jones@linaro.org> <1401452797-29521-2-git-send-email-lee.jones@linaro.org> <20140530123656.GC2742@katana> <20140530133405.GB29731@lee--X1> <20140530174800.GA4917@katana> <20140530192516.GA4319@lee--X1> <20140531134805.GA3287@katana> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:RAu86f+/iUC3o9KwDvULdQ2sCEAN1CSI6gxSV+V8NnzT8dpp+AW ETKRmymnhyq7g9jlOdnPgRZhC3VbwKt3IE1ibkYb100KY4Xpq3hDIuQW4aP21dZfkIwC0PB RQXIWBbkTzWyW/XWfDIOpv6IQXTPf6TIPkQphhOuTEfccqO6EW7a7fv3tWnSvVUTfSjBnmp 1bEeVLhXFGSOiMFt+K9+g== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 02.06.2014 14:16, schrieb Linus Walleij: > On Sat, May 31, 2014 at 3:48 PM, Wolfram Sang wrote: >> >>> Right, I read the function which provides the functionality, but my >>> point is; I don't think my patch changes the semantics in a way which >>> would adversely affect this option. If you think that it does, can you >>> specify how please? >> >> Currently, if a driver would be DT only and does not provide a seperate >> i2c_device_id table, then the driver is unusable with method 4. I don't >> like to have some drivers being capable of it and some not. >> >>> Does the sysfs method create a i2c_device_id table? If not, how does >>> it probe successfully pre-patch? >> >> The sysfs method creates a device. Its name is matched against >> i2c_device_ids only since it does not have a node pointer for DT to be >> matched against. > > Is this really so useful on embedded systems? > > I was under the impression that this method was something used > on say PC desktops with temperature monitors and EEPROMs > on some I2C link on the PCB, usage entirely optional and fun > for userspace hacks. > We use it for dynamic instantiating whole subsystems with multiplexers, sensors, controllers in an embedded system. The device list is taken from an I2C eeprom which gets read on hotplug. KR Michael From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Lawnick Subject: Re: [PATCH] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices Date: Mon, 02 Jun 2014 16:29:45 +0200 Message-ID: <538C8A59.2070907@gmx.de> References: <1401452797-29521-1-git-send-email-lee.jones@linaro.org> <1401452797-29521-2-git-send-email-lee.jones@linaro.org> <20140530123656.GC2742@katana> <20140530133405.GB29731@lee--X1> <20140530174800.GA4917@katana> <20140530192516.GA4319@lee--X1> <20140531134805.GA3287@katana> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linus Walleij , Wolfram Sang , Grant Likely Cc: Lee Jones , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-i2c@vger.kernel.org Am 02.06.2014 14:16, schrieb Linus Walleij: > On Sat, May 31, 2014 at 3:48 PM, Wolfram Sang wrote: >> >>> Right, I read the function which provides the functionality, but my >>> point is; I don't think my patch changes the semantics in a way which >>> would adversely affect this option. If you think that it does, can you >>> specify how please? >> >> Currently, if a driver would be DT only and does not provide a seperate >> i2c_device_id table, then the driver is unusable with method 4. I don't >> like to have some drivers being capable of it and some not. >> >>> Does the sysfs method create a i2c_device_id table? If not, how does >>> it probe successfully pre-patch? >> >> The sysfs method creates a device. Its name is matched against >> i2c_device_ids only since it does not have a node pointer for DT to be >> matched against. > > Is this really so useful on embedded systems? > > I was under the impression that this method was something used > on say PC desktops with temperature monitors and EEPROMs > on some I2C link on the PCB, usage entirely optional and fun > for userspace hacks. > We use it for dynamic instantiating whole subsystems with multiplexers, sensors, controllers in an embedded system. The device list is taken from an I2C eeprom which gets read on hotplug. KR Michael From mboxrd@z Thu Jan 1 00:00:00 1970 From: ml.lawnick@gmx.de (Michael Lawnick) Date: Mon, 02 Jun 2014 16:29:45 +0200 Subject: [PATCH] i2c: Make I2C ID tables non-mandatory for DT'ed and/or ACPI'ed devices In-Reply-To: References: <1401452797-29521-1-git-send-email-lee.jones@linaro.org> <1401452797-29521-2-git-send-email-lee.jones@linaro.org> <20140530123656.GC2742@katana> <20140530133405.GB29731@lee--X1> <20140530174800.GA4917@katana> <20140530192516.GA4319@lee--X1> <20140531134805.GA3287@katana> Message-ID: <538C8A59.2070907@gmx.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Am 02.06.2014 14:16, schrieb Linus Walleij: > On Sat, May 31, 2014 at 3:48 PM, Wolfram Sang wrote: >> >>> Right, I read the function which provides the functionality, but my >>> point is; I don't think my patch changes the semantics in a way which >>> would adversely affect this option. If you think that it does, can you >>> specify how please? >> >> Currently, if a driver would be DT only and does not provide a seperate >> i2c_device_id table, then the driver is unusable with method 4. I don't >> like to have some drivers being capable of it and some not. >> >>> Does the sysfs method create a i2c_device_id table? If not, how does >>> it probe successfully pre-patch? >> >> The sysfs method creates a device. Its name is matched against >> i2c_device_ids only since it does not have a node pointer for DT to be >> matched against. > > Is this really so useful on embedded systems? > > I was under the impression that this method was something used > on say PC desktops with temperature monitors and EEPROMs > on some I2C link on the PCB, usage entirely optional and fun > for userspace hacks. > We use it for dynamic instantiating whole subsystems with multiplexers, sensors, controllers in an embedded system. The device list is taken from an I2C eeprom which gets read on hotplug. KR Michael