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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A6A75C433DF for ; Wed, 13 May 2020 18:49:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A1922065C for ; Wed, 13 May 2020 18:49:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390235AbgEMStV (ORCPT ); Wed, 13 May 2020 14:49:21 -0400 Received: from relay9-d.mail.gandi.net ([217.70.183.199]:38075 "EHLO relay9-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389392AbgEMStU (ORCPT ); Wed, 13 May 2020 14:49:20 -0400 X-Originating-IP: 2.224.242.101 Received: from uno.localdomain (2-224-242-101.ip172.fastwebnet.it [2.224.242.101]) (Authenticated sender: jacopo@jmondi.org) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id 9D623FF806; Wed, 13 May 2020 18:49:15 +0000 (UTC) Date: Wed, 13 May 2020 20:52:32 +0200 From: Jacopo Mondi To: Laurent Pinchart Cc: Jacopo Mondi , mchehab@kernel.org, hverkuil-cisco@xs4all.nl, sakari.ailus@linux.intel.com, niklas.soderlund+renesas@ragnatech.se, kieran.bingham@ideasonboard.com, dave.stevenson@raspberrypi.com, hyun.kwon@xilinx.com, linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH v2 0/6] v4l2-subdev: Introduce get_mbus_format pad op Message-ID: <20200513185232.z4vvkaa4dhpgip2y@uno.localdomain> References: <20200415105004.2497356-1-jacopo+renesas@jmondi.org> <20200420020228.GF15673@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200420020228.GF15673@pendragon.ideasonboard.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Laurent, On Mon, Apr 20, 2020 at 05:02:28AM +0300, Laurent Pinchart wrote: > Hi Jacopo, > > Thank you for the patches. > > On Wed, Apr 15, 2020 at 12:49:57PM +0200, Jacopo Mondi wrote: > > v2 introduces two new patches that could be likely squashed in later to > > deprecate the g_mbus_config() operation in documentation and expand the newly > > introduced function documentation by popular demand. > > > > Will report again the use cases I'm trying to address here: > > ------------------------------------------------------------------------------ > > Quoting: > > https://patchwork.kernel.org/cover/10855919/ > > "The use case this series cover is the following one: > > the Gen-3 R-Car boards include an ADV748x HDMI/CVBS to CSI-2 converter > > connected to its CSI-2 receivers. The ADV748x chip has recently gained support > > for routing both HDMI and analogue video streams through its 4 lanes TXA > > transmitter, specifically to support the Ebisu board that has a single CSI-2 > > receiver, compared to all other Gen-3 board where the ADV748x TXes are connected > > to different CSI-2 receivers, and where analogue video is streamed out from the > > ADV748x single lane TXB transmitter. > > To properly support transmission of analogue video through TXA, the number of > > data lanes shall be dynamically reduced to 1, in order to comply with the MIPI > > CSI-2 minimum clock frequency requirements" > > > > During the discussion of the RFC, Dave reported another use case for media > > bus parameter negotiation on his platform: > > https://patchwork.kernel.org/patch/10855923/#22569149 > > > > Another possible use case is for parallel bus multiplexing, where multiple image > > sensor share the parallel bus lines and they get activated alternatively through > > an enable signal. While this might not be most clever design, it's often seen > > in the wild, and this operation allow receivers to re-configure their bus > > parameter in between streaming session. > > Isn't this already supported today, with the bus configuration for each > source specified in the corresponding endpoint (on the receiver side) in > DT ? > I think you're right.. One should probably cache each endpoint configuration parsed at probe time.. I was thinking at multiple connections to the same endpoint, but seems it's not possible.. good, I'll drop this > > Hyun is now using this series to configure GMSL devices. > > ------------------------------------------------------------------------------ > > > > v1->v2: > > - Address Sakari's comment to use unsigned int in place of bools > > - Add two new patches to address documentation > > - Adjust rcar-csi2 patch as much as possible according to Niklas comments > > - Add Niklas's tags > > > > Jacopo Mondi (6): > > media: v4l2-subdv: Introduce get_mbus_config pad op > > media: v4l2-subdev: Deprecate g_mbus_config video op > > media: v4l2-subdev: Expand get_mbus_config doc > > media: i2c: adv748x: Adjust TXA data lanes number > > media: i2c: adv748x: Implement get_mbus_config > > media: rcar-csi2: Negotiate data lanes number > > > > drivers/media/i2c/adv748x/adv748x-core.c | 31 ++++++-- > > drivers/media/i2c/adv748x/adv748x-csi2.c | 15 ++++ > > drivers/media/i2c/adv748x/adv748x.h | 1 + > > drivers/media/platform/rcar-vin/rcar-csi2.c | 53 ++++++++++++- > > include/media/v4l2-subdev.h | 82 ++++++++++++++++++++- > > 5 files changed, 171 insertions(+), 11 deletions(-) > > > > -- > Regards, > > Laurent Pinchart