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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 57A29C4338F for ; Mon, 23 Aug 2021 09:35:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A66F613A2 for ; Mon, 23 Aug 2021 09:35:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231160AbhHWJfy (ORCPT ); Mon, 23 Aug 2021 05:35:54 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:37148 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230428AbhHWJfy (ORCPT ); Mon, 23 Aug 2021 05:35:54 -0400 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 140BC2A5; Mon, 23 Aug 2021 11:35:10 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1629711310; bh=kd/MLAPBcEPKOguXUModcCC+opNF464T1oJbxkgihuw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EIkz2RlBkIalaNR78KhTEA75s+l2i1P4EZG5OXICrEtbEFL3WiLAE3U51SI3snkNO rHiQKnaGruxODL7dPxdpp2Gtia0hxRPJHpoOYfAhWCsx0fATMfTP+Hf5uD9affQia0 WDF4/U1vr6rQZXTyIR3qitQCcmQliu3DuPiZRi6c= Date: Mon, 23 Aug 2021 12:34:59 +0300 From: Laurent Pinchart To: Jacopo Mondi Cc: Jacopo Mondi , Mauro Carvalho Chehab , Kieran Bingham , Niklas =?utf-8?Q?S=C3=B6derlund?= , Hans Verkuil , Sakari Ailus , Manivannan Sadhasivam , Thomas NIZAN , linux-renesas-soc@vger.kernel.org, linux-media@vger.kernel.org Subject: Re: [RFC 4/5] media: i2c: max9286: Fetch PIXEL_RATE in s_stream Message-ID: References: <20210817072703.1167-1-jacopo+renesas@jmondi.org> <20210817072703.1167-5-jacopo+renesas@jmondi.org> <20210823072008.p6qi5lg73jsfezwn@uno.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210823072008.p6qi5lg73jsfezwn@uno.localdomain> Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Jacopo, On Mon, Aug 23, 2021 at 09:20:08AM +0200, Jacopo Mondi wrote: > On Mon, Aug 23, 2021 at 05:17:05AM +0300, Laurent Pinchart wrote: > > On Tue, Aug 17, 2021 at 09:27:02AM +0200, Jacopo Mondi wrote: > > > The max9286 driver needs to fetch the remote serializer PIXEL_RATE > > > control value in order to compute its own one, as the sum of the > > > > s/its own one/its own/ (or its own pixel rate) > > > > > values reported by the connected subdevices. > > > > > > Currently the control is verified to be present at notifier's bound > > > time, which requires the serializer driver to register the control at > > > probe time. As the serializer driver might need to register the control > > > later, by adding the control handler of its connected sensor, post-pone > > > the max9286 check for the control availability at start stream time. > > > > > > Signed-off-by: Jacopo Mondi > > > --- > > > drivers/media/i2c/max9286.c | 6 +++++- > > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c > > > index 1b92d18a1f94..98fc90339a9e 100644 > > > --- a/drivers/media/i2c/max9286.c > > > +++ b/drivers/media/i2c/max9286.c > > > @@ -595,7 +595,7 @@ static int max9286_notify_bound(struct v4l2_async_notifier *notifier, > > > max9286_check_config_link(priv, priv->source_mask); > > > max9286_configure_i2c(priv, false); > > > > > > - return max9286_set_pixelrate(priv); > > > + return 0; > > > } > > > > > > static void max9286_notify_unbind(struct v4l2_async_notifier *notifier, > > > @@ -674,6 +674,10 @@ static int max9286_s_stream(struct v4l2_subdev *sd, int enable) > > > int ret; > > > > > > if (enable) { > > > + ret = max9286_set_pixelrate(priv); > > > + if (ret) > > > + return ret; > > > > That's very likely not going to work. The CSI-2 receiver connected to > > the max9286 will need to know the pixel rate as part of its > > initialization sequence, before calling .s_stream(1) on the max9286. > > How so ? The R-Car CSI-2 receiver feteches the pixel rate at s_stream > time, I thought it was customary to do so. What is it needed for before > streamon time ? At stream on time is usually fine, but the CSI-2 receiver usually needs to be configured before starting the source, not after. > > > + > > > /* > > > * The frame sync between cameras is transmitted across the > > > * reverse channel as GPIO. We must open all channels while -- Regards, Laurent Pinchart