From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751748AbcF0L5o (ORCPT ); Mon, 27 Jun 2016 07:57:44 -0400 Received: from zencphosting06.zen.co.uk ([82.71.204.9]:35550 "EHLO zencphosting06.zen.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750869AbcF0L5m (ORCPT ); Mon, 27 Jun 2016 07:57:42 -0400 Subject: Re: [PATCH v5 0/9] Output raw touch data via V4L2 To: Hans Verkuil References: <1466633313-15339-1-git-send-email-nick.dyer@itdev.co.uk> <30c68dab-b970-03d5-797b-3376d9d0dc10@xs4all.nl> Cc: Dmitry Torokhov , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, Benjamin Tissoires , Benson Leung , Alan Bowens , Javier Martinez Canillas , Chris Healy , Henrik Rydberg , Andrew Duggan , James Chen , Dudley Du , Andrew de los Reyes , sheckylin@chromium.org, Peter Hutterer , Florian Echtler , mchehab@osg.samsung.com From: Nick Dyer Message-ID: <8be600b6-a424-ddda-8672-1aed4e925fe8@itdev.co.uk> Date: Mon, 27 Jun 2016 12:57:26 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <30c68dab-b970-03d5-797b-3376d9d0dc10@xs4all.nl> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-OutGoing-Spam-Status: No, score=-1.4 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - zencphosting06.zen.co.uk X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - itdev.co.uk X-Get-Message-Sender-Via: zencphosting06.zen.co.uk: authenticated_id: nick.dyer@itdev.co.uk X-Authenticated-Sender: zencphosting06.zen.co.uk: nick.dyer@itdev.co.uk Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Hans- Thanks for reviewing this again in such detail. On 27/06/2016 12:26, Hans Verkuil wrote: > On 06/23/2016 12:08 AM, Nick Dyer wrote: >> This is a series of patches to add output of raw touch diagnostic data via V4L2 >> to the Atmel maXTouch and Synaptics RMI4 drivers. >> >> It's a rewrite of the previous implementation which output via debugfs: it now >> uses a V4L2 device in a similar way to the sur40 driver. >> >> We have a utility which can read the data and display it in a useful format: >> https://github.com/ndyer/heatmap/commits/heatmap-v4l >> >> These patches are also available from >> https://github.com/ndyer/linux/commits/v4l-touch-2016-06-22 >> >> Changes in v5 (Hans Verkuil review): >> - Update v4l2-core: >> - Add VFL_TYPE_TOUCH, V4L2_BUF_TYPE_TOUCH_CAPTURE and V4L2_CAP_TOUCH > > The use of V4L2_CAP_TOUCH and V4L2_BUF_TYPE_TOUCH_CAPTURE is very inconsistent. > What is the rationale of adding V4L2_BUF_TYPE_TOUCH_CAPTURE? I can't remember > asking for it. I am afraid that I missed updating atmel_mxt_ts from V4L2_BUF_TYPE_VIDEO_CAPTURE to V4L2_BUF_TYPE_TOUCH_CAPTURE, which has confused the situation. Perhaps I read too much into your request that I look at the way that SDR is treated. When I started going through the code paths in v4l2-core and v4l2-compliance, it seemed cleaner to treat touch as completely separate, hence introducing the new BUF_TYPE. I'm happy to try it without this. > And wouldn't the use of V4L2_BUF_TYPE_TOUCH_CAPTURE break userspace for sur40? I think it is likely, yes. And it looks like that would make Florian unhappy. > I'm ambiguous towards having a V4L2_BUF_TYPE_TOUCH_CAPTURE, to be honest. > > I would also recommend renaming V4L2_CAP_TOUCH to V4L2_CAP_TOUCH_CAPTURE. Do you agree with the following changes: - Rename V4L2_CAP_TOUCH to V4L2_CAP_TOUCH_CAPTURE. - Touch devices should register both V4L2_CAP_VIDEO_CAPTURE and V4L2_CAP_TOUCH_CAPTURE. - Get rid of V4L2_BUF_TYPE_TOUCH_CAPTURE and use V4L2_BUF_TYPE_VIDEO_CAPTURE. In v4l2-ioctl.c if we need to force particular pix formats for touch, it will need to look at V4L2_CAP_TOUCH_CAPTURE. Your other review comments look straightforward to address - thanks. I should say, you can see my current changes to v4l2-compliance here: https://github.com/ndyer/v4l-utils/commit/07e00c33 Should I post them along with the kernel patches next time? > > I can imagine an embedded usb gadget device that outputs touch data to a PC. > > Regards, > > Hans