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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_NEOMUTT 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 06E9DC43381 for ; Mon, 4 Mar 2019 12:10:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D161220815 for ; Mon, 4 Mar 2019 12:10:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726061AbfCDMKN (ORCPT ); Mon, 4 Mar 2019 07:10:13 -0500 Received: from mga04.intel.com ([192.55.52.120]:7556 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725997AbfCDMKN (ORCPT ); Mon, 4 Mar 2019 07:10:13 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Mar 2019 04:10:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,440,1544515200"; d="scan'208";a="304220561" Received: from paasikivi.fi.intel.com ([10.237.72.42]) by orsmga005.jf.intel.com with ESMTP; 04 Mar 2019 04:10:06 -0800 Received: by paasikivi.fi.intel.com (Postfix, from userid 1000) id 245A2207E2; Mon, 4 Mar 2019 14:10:05 +0200 (EET) Date: Mon, 4 Mar 2019 14:10:05 +0200 From: Sakari Ailus To: Marco Felsch Cc: hans.verkuil@cisco.com, mchehab@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com, linux-media@vger.kernel.org, devicetree@vger.kernel.org, graphics@pengutronix.de Subject: Re: [PATCH 1/3] media: dt-bindings: add bindings for Toshiba TC358746 Message-ID: <20190304121004.qlqf2guz2yt7vnvu@paasikivi.fi.intel.com> References: <20181218141240.3056-1-m.felsch@pengutronix.de> <20181218141240.3056-2-m.felsch@pengutronix.de> <20190218100333.qvptfllrd4pyhsyb@paasikivi.fi.intel.com> <20190301105235.a23jwiwmxejuv2yf@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190301105235.a23jwiwmxejuv2yf@pengutronix.de> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Macro, On Fri, Mar 01, 2019 at 11:52:35AM +0100, Marco Felsch wrote: > Hi Sakari, > > On 19-02-18 12:03, Sakari Ailus wrote: > > Hi Marco, > > > > My apologies for reviewing this so late. You've received good comments > > already. I have a few more. > > Thanks for your review for the other patches as well =) Sorry for my > delayed response. > > > On Tue, Dec 18, 2018 at 03:12:38PM +0100, Marco Felsch wrote: > > > Add corresponding dt-bindings for the Toshiba tc358746 device. > > > > > > Signed-off-by: Marco Felsch > > > --- > > > .../bindings/media/i2c/toshiba,tc358746.txt | 80 +++++++++++++++++++ > > > 1 file changed, 80 insertions(+) > > > create mode 100644 Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.txt > > > > > > diff --git a/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.txt b/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.txt > > > new file mode 100644 > > > index 000000000000..499733df744a > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.txt > > > @@ -0,0 +1,80 @@ > > > +* Toshiba TC358746 Parallel to MIPI CSI2-TX or MIPI CSI2-RX to Parallel Bridge > > > + > > > +The Toshiba TC358746 is a bridge that converts a Parallel-in stream to MIPI CSI-2 TX > > > +or a MIPI CSI-2 RX stream into a Parallel-out. It is programmable through I2C. > > > > This is interesting. The driver somehow needs to figure out the direction > > of the data flow if it does not originate from DT. I guess it shouldn't as > > it's not the property of an individual device, albeit in practice in all > > hardware I've seen the direction of the pipeline is determinable and this > > is visible in the kAPI as well. So I'm suggesting no changes due to this in > > bindings, likely we'll need to address it somehow elsewhere going forward. > > What did you mean with "... and this is visible in the kAPI as well"? > I'm relative new in the linux-media world but I never saw a device which > supports two directions. Our customer which uses that chip use it > only in parallel-in/csi-out mode. To be flexible the switching should be > done by a subdev-ioctl but it is also reasonable to define a default value > within the DT. What I meant that the V4L2 sub-device API does not provide any information on the direction. It is implicit --- MC does, but it does it based on the links created by the driver. I agree a DT property would be a good way to tell this, especially now that there's a related hardware configuration (but which the software cannot obtain directly). -- Regards, Sakari Ailus sakari.ailus@linux.intel.com