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 D573CC77B73 for ; Tue, 6 Jun 2023 18:18:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236543AbjFFSSI (ORCPT ); Tue, 6 Jun 2023 14:18:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229682AbjFFSR7 (ORCPT ); Tue, 6 Jun 2023 14:17:59 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7794E43; Tue, 6 Jun 2023 11:17:58 -0700 (PDT) Received: from pendragon.ideasonboard.com (om126253223039.31.openmobile.ne.jp [126.253.223.39]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 4AB13289; Tue, 6 Jun 2023 20:17:30 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1686075451; bh=DRb6m39CrBBWcLpikvhKIWv1Q1828m7KdCBih5G281w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Qu3Z1XQ809WqGdIgjtY3f05JMvA+RplMGGce+5p7si2wI02VVNK37bm7kNk3fAwme DkrfdofKgq73NsSIp9Ww/8znc/hgIvYPXWRYLEnD9cJoP21QaDwanWWss6Yugn2dti NffhH7KDR6MYu/RDbVJjBgH1+v7kVn0iyzSiR+f0= Date: Tue, 6 Jun 2023 21:17:52 +0300 From: Laurent Pinchart To: Conor Dooley Cc: Tommaso Merciai , jacopo.mondi@ideasonboard.com, martin.hecht@avnet.eu, michael.roeder@avnet.eu, linuxfancy@googlegroups.com, Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Liam Girdwood , Mark Brown , Sakari Ailus , Hans Verkuil , Marco Felsch , Gerald Loacker , Mikhail Rudenko , Shawn Tu , Linus Walleij , Benjamin Mugnier , Krzysztof =?utf-8?Q?Ha=C5=82asa?= , Nicholas Roth , linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/3] media: dt-bindings: alvium: add document YAML binding Message-ID: <20230606181752.GC14101@pendragon.ideasonboard.com> References: <20230606155416.260941-1-tomm.merciai@gmail.com> <20230606155416.260941-3-tomm.merciai@gmail.com> <20230606163656.GI25679@pendragon.ideasonboard.com> <20230606-jaundice-womankind-7e583789fb7a@spud> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230606-jaundice-womankind-7e583789fb7a@spud> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Jun 06, 2023 at 07:07:42PM +0100, Conor Dooley wrote: > Hey Laurent, Tommaso, > > On Tue, Jun 06, 2023 at 07:36:56PM +0300, Laurent Pinchart wrote: > > On Tue, Jun 06, 2023 at 05:54:03PM +0200, Tommaso Merciai wrote: > > > > + alliedvision,lp2hs-delay-us: > > > + maxItems: 1 > > > + description: > > > + Low power to high speed delay time in microseconds. > > > > You can drop "in microseconds", that's implied by the suffix. > > > > > + The purpose of this property is force a DPhy reset for the period > > > + described by the microseconds on the property, before it starts > > > + streaming. To be clear, with that value bigger than 0 the Alvium > > > + forces a dphy-reset on all lanes for that period. That means all > > > + lanes go up into low power state. This may help a csi2 rx ip to > > > + reset if that IP can't deal with a continous clock. > > > > I'd like to propose what I think is a clearer version: > > > > description: | > > Low power to high speed delay time. > > > > If the value is larger than 0, the camera forces a reset of all > > D-PHY lanes for the duration specified by this property. All lanes > > will transition to the low-power state and back to the high-speed > > state after the delay. Otherwise the lanes will transition to and > > remain in the high-speed state immediately after power on. > > > > This is meant to help CSI-2 receivers synchronizing their D-PHY > > RX. > > Question about the property. > Why not make it have a minimum value of 1 and drop the special-case > behaviour for zero? The property is optional, so it can indeed be omitted if no delay is desired. I have no strong preference on whether or not to allow 0 as a valid value. -- Regards, Laurent Pinchart