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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 E6A1FC47255 for ; Mon, 11 May 2020 13:58:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB1FD20736 for ; Mon, 11 May 2020 13:58:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=metafoo.de header.i=@metafoo.de header.b="IupyqNtD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730351AbgEKN6I (ORCPT ); Mon, 11 May 2020 09:58:08 -0400 Received: from www381.your-server.de ([78.46.137.84]:53476 "EHLO www381.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730153AbgEKN6H (ORCPT ); Mon, 11 May 2020 09:58:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=metafoo.de; s=default2002; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=No2f5Smp3GbnzqLRvMbPPPhjw0H+cM11eeZ98PnOg+U=; b=IupyqNtDxFLIEcY8GLnncia2JZ EkXsyjfLq8i7LXy2tEBBndaIzHL1XUIlIItywQK3Io4qOglCb3uxBCambCh+zw3Bk0OcWxzstNvyE gHwmFluyMmjdJnQMVv4UTiFXf3gH/5mA3IXsOTDj9eBmCF/Sb2ULPnPOIe35weHJGIDV+L96kLpQd LqFaJ6nZwlTQVteZkvHo4NPfUJeYSZGLMIF9azWj8yGpLgPKAGaBOZ2Dm6lHwAM4HbeydBtWStxnL 5QnYzb+S9qCAYQ6bKH2sWE40qhV9SxJjsZ/tlXF6LrtQhJQYpzyQsnOfWkNXoVuKoCTtLgYzhMPzs WVCDevmA==; Received: from sslproxy03.your-server.de ([88.198.220.132]) by www381.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1jY8wU-0008Qr-Hq; Mon, 11 May 2020 15:58:02 +0200 Received: from [82.135.66.51] (helo=[192.168.178.20]) by sslproxy03.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jY8wU-000RCZ-9o; Mon, 11 May 2020 15:58:02 +0200 Subject: Re: [RFC PATCH 00/14] iio: buffer: add support for multiple buffers To: "Ardelean, Alexandru" , "jic23@kernel.org" Cc: "linux-kernel@vger.kernel.org" , "linux-iio@vger.kernel.org" References: <20200508135348.15229-1-alexandru.ardelean@analog.com> <20200510110958.29046a18@archlinux> <8c5d9ef5ed4ea9037c5459daa2044d1cd7c5db7a.camel@analog.com> <554fe46f0cdd1cafb313f534c0edd93f5686b806.camel@analog.com> <7d2c8174e345bf8e241d48de65066d2606143503.camel@analog.com> From: Lars-Peter Clausen Message-ID: <9ae7e69b-f4ce-dd2b-d70b-2aac66b19814@metafoo.de> Date: Mon, 11 May 2020 15:58:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <7d2c8174e345bf8e241d48de65066d2606143503.camel@analog.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Authenticated-Sender: lars@metafoo.de X-Virus-Scanned: Clear (ClamAV 0.102.2/25809/Mon May 11 14:16:55 2020) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/11/20 3:24 PM, Ardelean, Alexandru wrote: > On Mon, 2020-05-11 at 13:03 +0000, Ardelean, Alexandru wrote: >> [External] >> >> On Mon, 2020-05-11 at 12:37 +0200, Lars-Peter Clausen wrote: >>> [External] >>> >>> On 5/11/20 12:33 PM, Ardelean, Alexandru wrote: >>>> On Sun, 2020-05-10 at 11:09 +0100, Jonathan Cameron wrote: >>>>> [External] >>>>> >>>>> On Sat, 9 May 2020 10:52:14 +0200 >>>>> Lars-Peter Clausen wrote: >>>>> >>>>>> On 5/8/20 3:53 PM, Alexandru Ardelean wrote: >>>>>>> [...] >>>>>>> What I don't like, is that iio:device3 has iio:buffer3:0 (to 3). >>>>>>> This is because the 'buffer->dev.parent = &indio_dev->dev'. >>>>>>> But I do feel this is correct. >>>>>>> So, now I don't know whether to leave it like that or symlink to >>>>>>> shorter >>>>>>> versions like 'iio:buffer3:Y' -> 'iio:device3/bufferY'. >>>>>>> The reason for naming the IIO buffer devices to 'iio:bufferX:Y' is >>>>>>> mostly to make the names unique. It would have looked weird to do >>>>>>> '/dev/buffer1' if I would have named the buffer devices 'bufferX'. >>>>>>> >>>>>>> So, now I'm thinking of whether all this is acceptable. >>>>>>> Or what is acceptable? >>>>>>> Should I symlink 'iio:device3/iio:buffer3:0' -> >>>>>>> 'iio:device3/buffer0'? >>>>>>> What else should I consider moving forward? >>>>>>> What means forward? >>>>>>> Where did I leave my beer? >>>>>> Looking at how the /dev/ devices are named I think we can provide a >>>>>> name >>>>>> that is different from the dev_name() of the device. Have a look at >>>>>> device_get_devnode() in drivers/base/core.c. We should be able to >>>>>> provide the name for the chardev through the devnode() callback. >>>>>> >>>>>> While we are at this, do we want to move the new devices into an iio >>>>>> subfolder? So iio/buffer0:0 instead of iio:buffer0:0? >>>>> Possibly on the folder. I can't for the life of me remember why I >>>>> decided >>>>> not to do that the first time around - I'll leave it at the >>>>> mysterious "it may turn out to be harder than you'd think..." >>>>> Hopefully not ;) >>>> I was also thinking about the /dev/iio subfolder while doing this. >>>> I can copy that from /dev/input >>>> They seem to do it already. >>>> I don't know how difficult it would be. But it looks like a good >>>> precedent. >>> All you have to do is return "iio/..." from the devnode() callback. >> I admit I did not look closely into drivers/input/input.c before mentioning >> this >> as as good precedent. >> >> But, I looks like /dev/inpput is a class. >> While IIO devices are a bus_type devices. >> Should we start implementing an IIO class? or? > What I should have highlighted [before] with this, is that there is no devnode() > callback for the bus_type [type]. But there is one in device_type :)