From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753215Ab3GNT5a (ORCPT ); Sun, 14 Jul 2013 15:57:30 -0400 Received: from mail-la0-f47.google.com ([209.85.215.47]:33562 "EHLO mail-la0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753155Ab3GNT52 (ORCPT ); Sun, 14 Jul 2013 15:57:28 -0400 Message-ID: <51E302A4.6080801@cogentembedded.com> Date: Sun, 14 Jul 2013 23:57:24 +0400 From: Sergei Shtylyov Organization: Cogent Embedded User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: Lars-Peter Clausen CC: Arnd Bergmann , Greg KH , linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org Subject: Re: [PATCH] misc: add driver for Renesas R-Car Gyro-ADC/speed-pulse interfaces References: <201307130351.42967.sergei.shtylyov@cogentembedded.com> <20130713005702.GA14788@kroah.com> <51E0AA24.6070203@cogentembedded.com> <201307130958.16533.arnd@arndb.de> <51E1D406.9090702@cogentembedded.com> <51E25D6A.3090106@metafoo.de> In-Reply-To: <51E25D6A.3090106@metafoo.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. On 07/14/2013 12:12 PM, Lars-Peter Clausen wrote: >>>>> And are you sure you want to control this through sysfs? There's no >>>>> other better user/kernel apis for it? >>>> I found none, besides ioctl(), as the device driven is rather >>>> unique. But I thought that sysfs is "ioctl() today", so I went with it... >>> It does sound like it would fit better into IIO than just a misc driver, >>> even if it's the only hardware of its kind. >> I got somewhat familiarized myself with drivers/iio/ infrastructure and I >> have found a place only the for ADC device in which the customer currently >> has no interest. >> The other trouble is that I'll have to backport this driver to 3.4 which >> doesn't contain the IIO infrastructure at all. :-( > It has, it's just still in staging in 3.4. But the API (except for minor > modifications) and more importantly the ABI are the same. Thank you for the useful information. I wouldn't probably have figured it out to search there. > There is a angular velocity channel type in IIO. maybe that could be used to > report the Speed-Pulse-ADC values. You probably misunderstood from my terse description. Multichannel ADC interface is separate from the speed-pulse interface which has on its single input digital PWM signal of varying frequency. Speed pulse i/f measures pulse count and period. I've found no adequate channel type in IIO infrastructure so far. I'll mail the IIO maintainers with a request for help probably... > - Lars WBR, Sergei