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=-2.3 required=3.0 tests=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 49063C433DF for ; Tue, 26 May 2020 08:55:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29A742068D for ; Tue, 26 May 2020 08:55:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731625AbgEZIzk (ORCPT ); Tue, 26 May 2020 04:55:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731414AbgEZIzk (ORCPT ); Tue, 26 May 2020 04:55:40 -0400 Received: from hillosipuli.retiisi.org.uk (hillosipuli.retiisi.org.uk [IPv6:2a01:4f9:c010:4572::81:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBB98C03E97E; Tue, 26 May 2020 01:55:39 -0700 (PDT) Received: from valkosipuli.localdomain (valkosipuli.retiisi.org.uk [IPv6:2a01:4f9:c010:4572::80:2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by hillosipuli.retiisi.org.uk (Postfix) with ESMTPS id 3E902634C87; Tue, 26 May 2020 11:54:50 +0300 (EEST) Received: from sailus by valkosipuli.localdomain with local (Exim 4.92) (envelope-from ) id 1jdVMI-0002RU-AE; Tue, 26 May 2020 11:54:50 +0300 Date: Tue, 26 May 2020 11:54:50 +0300 From: Sakari Ailus To: Laurent Pinchart Cc: Kieran Bingham , linux-renesas-soc@vger.kernel.org, linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Mauro Carvalho Chehab , Kieran Bingham , Jacopo Mondi , Niklas =?iso-8859-1?Q?S=F6derlund?= , Hans Verkuil , Hyun Kwon , Manivannan Sadhasivam , Rob Herring , Jacopo Mondi , Laurent Pinchart , Niklas =?iso-8859-1?Q?S=F6derlund?= Subject: Re: [PATCH v9 2/4] media: i2c: Add MAX9286 driver Message-ID: <20200526085450.GF8214@valkosipuli.retiisi.org.uk> References: <20200512155105.1068064-1-kieran.bingham+renesas@ideasonboard.com> <20200512155105.1068064-3-kieran.bingham+renesas@ideasonboard.com> <20200516215103.GA857@valkosipuli.retiisi.org.uk> <930009cd-d887-752a-4f1f-567c795101ee@ideasonboard.com> <20200520005020.GQ3820@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200520005020.GQ3820@pendragon.ideasonboard.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Laurent, On Wed, May 20, 2020 at 03:50:20AM +0300, Laurent Pinchart wrote: > Hi Sakari, > > On Mon, May 18, 2020 at 12:45:18PM +0100, Kieran Bingham wrote: > > Hi Sakari, > > > > There are only fairly minor comments here, fix ups will be included in a > > v10. > > > > Is there anything major blocking integration? > > > > On 16/05/2020 22:51, Sakari Ailus wrote: > > > On Tue, May 12, 2020 at 04:51:03PM +0100, Kieran Bingham wrote: > > > > > > ... > > > > > >> +static int max9286_enum_mbus_code(struct v4l2_subdev *sd, > > >> + struct v4l2_subdev_pad_config *cfg, > > >> + struct v4l2_subdev_mbus_code_enum *code) > > >> +{ > > >> + if (code->pad || code->index > 0) > > >> + return -EINVAL; > > >> + > > >> + code->code = MEDIA_BUS_FMT_UYVY8_2X8; > > > > > > Why UYVY8_2X8 and not UYVY8_1X16? In general, the single sample / pixel > > > variant of the format is generally used on the serial busses. This choice > > > was made when serial busses were introduced. > > This is a bit of a tricky one. On the camera size, for the RDACM20, the > O10635 sensor outputs UYVY8_2X8. This if fed to the MAX9271 serializer, > which doesn't care about the data type. The MAX9271 has a 16-bit input > bus, with 10 bits reserved for data, 2 bits dynamically configurable > to carry H/V sync or extra data, and 4 bits dynamically configurable to > carry GPIOs or extra data. The 16-bit words are then serialized (it's a > bit more complicated, when using the H/V sync signals they are > transmitted in a different way, and the MAX9271 also supports a DDR mode > that makes the "serial link word" carry up to 30 bits). Effectively, the > two samples of UYVY8_2X8 are serialized in a 16-bit word each. > > Sakari, with this information in mind, what would you recommend ? As this pad describes a serial bus --- doesn't it? --- it should use the same formats as other serial busses such as CSI-2. I.e. the 1X16 variant. -- Regards, Sakari Ailus