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 CEC7AC6379F for ; Tue, 21 Feb 2023 12:42:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234681AbjBUMmj (ORCPT ); Tue, 21 Feb 2023 07:42:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233901AbjBUMmh (ORCPT ); Tue, 21 Feb 2023 07:42:37 -0500 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AC50166CB; Tue, 21 Feb 2023 04:42:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676983356; x=1708519356; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=qdSAFaUWp6AvhtEnnIj1yeelAd4itBgU8TC7d7tUjeI=; b=gQ+9VuhWDnTarRLQ76/+M3IZna57jk2dVOgkyEGmnMrBSX83E/b1Ki5y 2CLqFkKPg4RgTO5/gHepmdDHKXybBFWF2CHUFAVEYZ79MTyLaHrfxRAc0 RpbF7+sYUYO8bgVC0z0ai1xxFFW8NUFThWjndDXPLr3bZw7Wqv/P8kBVR qn02ynHO9zngSzMFe9QE8pvtHwbE48Q9+2D7bTOMI5gn/P08CyYRSpipl tDJKwTHC7igLnyRvPhqmpef/OR9S0jTVj2cQebXCuZRMSqumKvGKxfOmS wnDi2qFF7gD6LFtF6XkN6+SolmxPWewo0oBZIvd6BMDh5t5QtZP+fHbZA w==; X-IronPort-AV: E=McAfee;i="6500,9779,10627"; a="320751456" X-IronPort-AV: E=Sophos;i="5.97,315,1669104000"; d="scan'208";a="320751456" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Feb 2023 04:42:35 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10627"; a="649165040" X-IronPort-AV: E=Sophos;i="5.97,315,1669104000"; d="scan'208";a="649165040" Received: from turnipsi.fi.intel.com (HELO kekkonen.fi.intel.com) ([10.237.72.44]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Feb 2023 04:42:34 -0800 Received: from kekkonen.localdomain (localhost [IPv6:::1]) by kekkonen.fi.intel.com (Postfix) with SMTP id 505861202B1; Tue, 21 Feb 2023 14:42:31 +0200 (EET) Date: Tue, 21 Feb 2023 14:42:31 +0200 From: Sakari Ailus To: Laurent Pinchart Cc: linux-media@vger.kernel.org, Jacopo Mondi , Rob Herring , devicetree@vger.kernel.org Subject: Re: [PATCH v2 1/2] media: dt-bindings: media: i2c: Add MT9M114 camera sensor binding Message-ID: References: <20220207012055.15158-1-laurent.pinchart@ideasonboard.com> <20220207012055.15158-2-laurent.pinchart@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Laurent, On Tue, Feb 21, 2023 at 01:52:46AM +0200, Laurent Pinchart wrote: > > > > > > + properties: > > > > > > + bus-type: > > > > > > + enum: [4, 5, 6] > > > > > > > > > > With bus-type 5, shouldn't you have the parallel interface sync signal > > > > > polarity properties? Possibly also others if the hardware supports them. > > > > > > > > As far as I can tell, the hardware has fixed polarities for all signals. > > > > Both hsync and vsync (called LINE_VALID and FRAME_VALID here) are active > > > > high. > > > > > > Right, then you won't need these. > > > > > > What about the link-frequencies property? > > > > That's something I've meant to ask, should the link-frequencies property > > be specified for parallel buses too, or only CSI-2 ? > > Any feedback on this ? Yes. It very likely matters there as well but probably less so than on CSI-2. link-frequencies isn't specific to CSI-2 either. > > > We also need to document how a DT writer should select the link > > frequencies. The process is complicated, saying that the property is > > required without explaining how the values can be computed (EMC > > constraints aside, just from a functional point of view) isn't nice. If > > you explain this to me, I can put it in a patch :-) > > Or on this ? :-) Generally the hardware people will tell you this when it matters. :-) But on a development board you can probably have anything the hardware supports. I guess we could add a few words on this to e.g. Documentation/driver-api/media/camera-sensor.rst . Most drivers will support a few frequencies only and sometimes the vendor, due to someone needing it, provides another configuration with a different frequency. Many sensors also have datasheets that are precise enough to calculate this yourself. -- Regards, Sakari Ailus