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=-10.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 2F2D6C433E1 for ; Sat, 25 Jul 2020 21:31:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05341206D8 for ; Sat, 25 Jul 2020 21:31:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="Pve+7WxW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727036AbgGYVbg (ORCPT ); Sat, 25 Jul 2020 17:31:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726926AbgGYVbg (ORCPT ); Sat, 25 Jul 2020 17:31:36 -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 CF7CBC08C5C0; Sat, 25 Jul 2020 14:31:35 -0700 (PDT) Received: from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 4302423D; Sat, 25 Jul 2020 23:31:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1595712693; bh=jzCVvUJiFPvDHKbRsrvnEOTmmBHou2QVTtxdK9/s4Lk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Pve+7WxW8V+hSFPXgi9ILGg3vNu9mw1T9Nox3aDDACbJzXp3UYhnIM52NXtRXukFZ zOzXeUQTklodTH/n7Gc3Bk+zSBs8PZtgmc2dvD5dwIWItrzqrXL407/EXNDElAMnG7 JMR2PQ+RnmaSCeWYyzvZUcBpCoejD6vbrghvK4DA= Date: Sun, 26 Jul 2020 00:31:25 +0300 From: Laurent Pinchart To: Sakari Ailus Cc: Jacopo Mondi , robh+dt@kernel.org, devicetree@vger.kernel.org, slongerbeam@gmail.com, linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Maxime Coquelin , Alexandre Torgue , "moderated list:ARM/STM32 ARCHITECTURE" Subject: Re: [PATCH 08/13] dt-bindings: media: ov5640: Remove data-shift Message-ID: <20200725213125.GE6253@pendragon.ideasonboard.com> References: <20200717132859.237120-1-jacopo+renesas@jmondi.org> <20200717132859.237120-9-jacopo+renesas@jmondi.org> <20200717205722.GJ5961@pendragon.ideasonboard.com> <20200723222259.GB829@valkosipuli.retiisi.org.uk> <20200723231549.GE21353@pendragon.ideasonboard.com> <20200725211833.GE829@valkosipuli.retiisi.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200725211833.GE829@valkosipuli.retiisi.org.uk> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Sakari, On Sun, Jul 26, 2020 at 12:18:33AM +0300, Sakari Ailus wrote: > On Fri, Jul 24, 2020 at 02:15:49AM +0300, Laurent Pinchart wrote: > > On Fri, Jul 24, 2020 at 01:22:59AM +0300, Sakari Ailus wrote: > > > On Fri, Jul 17, 2020 at 11:57:22PM +0300, Laurent Pinchart wrote: > > > > Hi Jacopo, > > > > > > > > (CC'ing Sakari) > > > > > > > > Thank you for the patch. > > > > > > > > On Fri, Jul 17, 2020 at 03:28:54PM +0200, Jacopo Mondi wrote: > > > > > The value of the data-shift property solely depend on the selected > > > > > bus width and it's not freely configurable. > > > > > > > > > > Remove it from the bindings document and update its users accordingly. > > > > > > > > Hmmmm that's an interesting one. Sakari, what do you think ? > > > > > > > > > Signed-off-by: Jacopo Mondi > > > > > --- > > > > > Documentation/devicetree/bindings/media/i2c/ov5640.yaml | 9 --------- > > > > > arch/arm/boot/dts/stm32mp157c-ev1.dts | 1 - > > > > > 2 files changed, 10 deletions(-) > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/media/i2c/ov5640.yaml b/Documentation/devicetree/bindings/media/i2c/ov5640.yaml > > > > > index 5e1662e848bd..ab700a1830aa 100644 > > > > > --- a/Documentation/devicetree/bindings/media/i2c/ov5640.yaml > > > > > +++ b/Documentation/devicetree/bindings/media/i2c/ov5640.yaml > > > > > @@ -92,12 +92,6 @@ properties: > > > > > parallel bus. > > > > > enum: [8, 10] > > > > > > > > > > - data-shift: > > > > > - description: | > > > > > - Shall be set to <2> for 8 bits parallel bus (lines 9:2 are used) or > > > > > - <0> for 10 bits parallel bus. > > > > > - enum: [0, 2] > > > > > > > > Should you document in the description of bus-width that data-shift is > > > > implied ? > > > > > > The purpose of the datas-shift property is to convey how the parallel bus > > > lines are connected for a given bus width for devices where it is > > > configurable. As this device does not not support that, then indeed this > > > property is not relevant for the device IMO. > > > > Could you elaborate on this ? I believe the case that Jacopo is > > describing connects D[9:2] from the sensor to D[7:0] of the receiver > > (Jacopo, could you confirm ?). Isn't that what data-shift is for ? > > Yes, it is. But in this case what data-shift configures is not configurable > as such but defined by another configuration, making the data-shift > property redundant. We generally haven't documented redundant things in DT > bindings --- for instance data-lanes is documented in bindings only if it > is configurable. Then I think we share the same understanding. I believe the documentation in video-interfaces.txt needs to be expanded, as it's quite terse and not very clear. > That said, it'd be nice to say which pins are used on less than full width > busses. -- Regards, Laurent Pinchart