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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBD5DC38145 for ; Wed, 7 Sep 2022 00:42:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229551AbiIGAmH (ORCPT ); Tue, 6 Sep 2022 20:42:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229516AbiIGAmG (ORCPT ); Tue, 6 Sep 2022 20:42:06 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A98886B5E for ; Tue, 6 Sep 2022 17:42:05 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 6F094478; Wed, 7 Sep 2022 02:42:02 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1662511322; bh=gWRBlQKPsWD6kSWHo+0jUUa2ZsAq4oT6y0XWRgUTf7Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cFD9yzem2BaXYq6Lo9QJ94CJMAzBj+P9eF42BdAkVcbhiOe2cpnQwedmS01hmlnAG IiLpM9YbllJ3sJvGmXMW8RlAu3zcp3OZabcA+J4QQcOEqjaDmnokGxZ1z5PSuyvC1F Fvg5RXE5zQ10dRRmSGylszjkWkEeu5SN1kgVQ/0s= Date: Wed, 7 Sep 2022 03:41:47 +0300 From: Laurent Pinchart To: Dave Stevenson Cc: Linux Media Mailing List , Sakari Ailus , Kieran Bingham , Nicolas Dufresne , Benjamin Gaignard , Hidenori Kobayashi , Paul Kocialkowski , Michael Olbrich , Ricardo Ribalda , Maxime Ripard , Daniel Scally , Jernej =?utf-8?Q?=C5=A0krabec?= , Niklas =?utf-8?Q?S=C3=B6derlund?= , Michael Tretter , Hans Verkuil , Philipp Zabel , Mauro Carvalho Chehab , Benjamin MUGNIER , Jacopo Mondi Subject: Re: [Media Summit] Imaging Sensor functionality Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Dave, On Tue, Sep 06, 2022 at 08:53:41PM +0300, Laurent Pinchart wrote: > On Tue, Sep 06, 2022 at 05:14:30PM +0100, Dave Stevenson wrote: > > Hi All. > > > > I realise that I'm in a slightly different position from many mainline > > Linux-media developers in that I see multiple use cases for the same > > sensor, rather than a driver predominantly being for one > > product/platform. I'm therefore wanting to look at generic solutions > > and fully featured drivers. Users get to decide the use cases, not the > > hardware designers. > > Could you clarify here what you mean by users and hardware designers ? > Users can be understood as > > - Users of the camera sensor, i.e. OEMs designing a product > - Users of the hardware platform , i.e. software developers writing > applications > - Users of the software, i.e. end-users > > Hardware designers could then equally mean > > - Sensor vendors > - SoC vendors > - Board vendors > - Product vendors > > > The issues I've raised are things that I've encountered and would > > benefit from a discussion to get views as to the direction that is > > perceived to be workable. I appreciate that some can not be solved > > immediately, but want to avoid too much bikeshedding in the first > > round of patches. > > What's realistic, and what pitfalls/limitations immediately jump out at people. > > > > Slides are at https://drive.google.com/file/d/1vjYJjTNRL1P3j6G4Nx2ZpjFtTBTNdeFG/view?usp=sharing > > Thank you, I will review that ASAP. A few questions: - Regarding the sensor synchronization, are you considering the trigger signal as signaling the beginning of exposure only, or also use cases where it controls the exposure duration ? - For VCM ringing reduction and standardization of parameters, are there examples you could share to explain this in more details, with the type of parameters that need to be specified ? And one comment. On slide 20/23, you wrote Likely to produce a load of boilerplate in all drivers. Abstract out an image sensor pinctrl helper? I think we need more than that, we need a large helper for camera sensors (in particular for raw sensors) that will bridge the large gap between the sensor and the V4L2 subdev API. There's too much boilerplate code already, and worse, different sensor drivers exposing the same feature to userspace in different ways. > > See you on Monday. -- Regards, Laurent Pinchart