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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 4324BC43441 for ; Thu, 15 Nov 2018 15:25:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 09DC5223CB for ; Thu, 15 Nov 2018 15:25:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=synopsys.com header.i=@synopsys.com header.b="WkhpOeeM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 09DC5223CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=synopsys.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388399AbeKPBdq (ORCPT ); Thu, 15 Nov 2018 20:33:46 -0500 Received: from smtprelay.synopsys.com ([198.182.60.111]:40282 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726432AbeKPBdq (ORCPT ); Thu, 15 Nov 2018 20:33:46 -0500 Received: from mailhost.synopsys.com (mailhost3.synopsys.com [10.12.238.238]) by smtprelay.synopsys.com (Postfix) with ESMTP id CC66A10C0EC0; Thu, 15 Nov 2018 07:25:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synopsys.com; s=mail; t=1542295529; bh=Q6NZD9Wbv7WgydIrv8pmXT6UfxGOHaZoRwnr+aqlxzI=; h=Subject:To:CC:References:From:Date:In-Reply-To:From; b=WkhpOeeMzUiGcFxAUo3hdOvPo6+rDzAgScnncer6Q2KVCZ2Kv2Pbyb/RUScI6vwdg D3WMrCLb5VJrJoWyuSEDPNehaqx6hW8p/TNRkIvAUivBpMMbutZ8NyjPFJnhLKmyls C0ksBahZmnYM513OQkYj7NWRGbLUSkH2/0TNu6TkzYnYBy5T37wRoxn/qc8l80mEVl HtWoKEycg6NkcNnbtGLjr259wl8ItffaOeclhciEvnHdS8V1PTIuf69dyiYwxtvFjr aOIKeUvcv859xczqLzTvaP6cZvdz5j1iaGRNBuOnMv3dHgJkdRRcMffF50PMCwB9xN SbSraXrKERgBA== Received: from US01WEHTC3.internal.synopsys.com (us01wehtc3.internal.synopsys.com [10.15.84.232]) by mailhost.synopsys.com (Postfix) with ESMTP id 1FE393CFD; Thu, 15 Nov 2018 07:25:28 -0800 (PST) Received: from DE02WEHTCA.internal.synopsys.com (10.225.19.92) by US01WEHTC3.internal.synopsys.com (10.15.84.232) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 15 Nov 2018 07:25:28 -0800 Received: from DE02WEHTCB.internal.synopsys.com (10.225.19.94) by DE02WEHTCA.internal.synopsys.com (10.225.19.92) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 15 Nov 2018 16:25:25 +0100 Received: from [10.0.2.15] (10.107.19.116) by DE02WEHTCB.internal.synopsys.com (10.225.19.80) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 15 Nov 2018 16:25:25 +0100 Subject: Re: [PATCH v10 0/9] Add the I3C subsystem To: Arnd Bergmann , Boris Brezillon CC: Vitor Soares , Wolfram Sang , Linux I2C , Jonathan Corbet , "open list:DOCUMENTATION" , gregkh , Przemyslaw Sroka , Arkadiusz Golec , Alan Douglas , Bartosz Folta , Damian Kos , "Alicja Jurasik-Urbaniak" , Cyprian Wronka , Suresh Punnoose , Rafal Ciepiela , Thomas Petazzoni , Nishanth Menon , Rob Herring , Pawel Moll , "Mark Rutland" , Ian Campbell , Kumar Gala , DTML , Linux Kernel Mailing List , Geert Uytterhoeven , Linus Walleij , Xiang Lin , "open list:GPIO SUBSYSTEM" , Sekhar Nori , Przemyslaw Gaj , Peter Rosin , Mike Shettel , Stephen Boyd , Mark Brown References: <20181026144333.12276-1-boris.brezillon@bootlin.com> <76b1d15d-232c-d8ba-5eba-8394e71be725@synopsys.com> <20181115135731.25f60990@bbrezillon> From: vitor Message-ID: <08a591ae-c75b-80b4-b608-ca92f6d932f9@synopsys.com> Date: Thu, 15 Nov 2018 15:25:11 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.107.19.116] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Arnd, On 15/11/18 14:25, Arnd Bergmann wrote: > I agree about better not exposing the bus as a /dev/i3c* node, and that we > probably do need to expose individual devices in some form to allow > writing complete user space drivers that can do everything a kernel driver > can do. > > Can you describe what a low-level interface to the device looks like > in the kernel? Can this be abstracted as simply pread()/pwrite() plus > an interrupt mechanism, or do we need a set of ioctl() operations as > well? Like in i2c is likely to need the ioctl() too. Best regards, Vitor Soares