From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:36188 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751864AbdASVtK (ORCPT ); Thu, 19 Jan 2017 16:49:10 -0500 Date: Thu, 19 Jan 2017 23:49:06 +0200 From: Sakari Ailus To: Pavel Machek Cc: robh+dt@kernel.org, devicetree@vger.kernel.org, ivo.g.dimitrov.75@gmail.com, sre@kernel.org, pali.rohar@gmail.com, linux-media@vger.kernel.org Subject: Re: [PATCHv2] dt: bindings: Add support for CSI1 bus Message-ID: <20170119214905.GD3205@valkosipuli.retiisi.org.uk> References: <20161228183036.GA13139@amd> <20170111225335.GA21553@amd> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170111225335.GA21553@amd> Sender: linux-media-owner@vger.kernel.org List-ID: Hi Pavel, On Wed, Jan 11, 2017 at 11:53:35PM +0100, Pavel Machek wrote: > From: Sakari Ailus > > In the vast majority of cases the bus type is known to the driver(s) > since a receiver or transmitter can only support a single one. There > are cases however where different options are possible. > > The existing V4L2 OF support tries to figure out the bus type and > parse the bus parameters based on that. This does not scale too well > as there are multiple serial busses that share common properties. > > Some hardware also supports multiple types of busses on the same > interfaces. > > Document the CSI1/CCP2 property strobe. It signifies the clock or > strobe mode. > > Signed-off-by: Sakari Ailus > Signed-off-by: Ivaylo Dimitrov > Signed-off-by: Pavel Machek > > diff --git a/Documentation/devicetree/bindings/media/video-interfaces.txt b/Documentation/devicetree/bindings/media/video-interfaces.txt > index 9cd2a36..08c4498 100644 > --- a/Documentation/devicetree/bindings/media/video-interfaces.txt > +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt > @@ -76,6 +76,11 @@ Optional endpoint properties > mode horizontal and vertical synchronization signals are provided to the > slave device (data source) by the master device (data sink). In the master > mode the data source device is also the source of the synchronization signals. > +- bus-type: data bus type. Possible values are: > + 0 - MIPI CSI2 > + 1 - parallel / Bt656 > + 2 - MIPI CSI1 > + 3 - CCP2 Actually, thinking about this again --- we only need to explictly specify busses if we're dealing with either CCP2 or CSI-1. The vast majority of the actual busses are and continue to be CSI-2 or either parallel or Bt.656. As they can be implicitly detected, we would have an option to just drop values 0 and 1 from above, i.e. only leave CSI-1 and CCP2. For now, specifying CSI-2 or parallel / Bt.656 adds no value as the old DT binaries without bus-type will need to be supported anyway. > - bus-width: number of data lines actively used, valid for the parallel busses. > - data-shift: on the parallel data busses, if bus-width is used to specify the > number of data lines, data-shift can be used to specify which data lines are > @@ -112,7 +117,8 @@ Optional endpoint properties > should be the combined length of data-lanes and clock-lanes properties. > If the lane-polarities property is omitted, the value must be interpreted > as 0 (normal). This property is valid for serial busses only. > - > +- strobe: Whether the clock signal is used as clock or strobe. Used > + with CCP2, for instance. How about the "ti,strobe-clock-inv" I proposed? No-one seems to know what this really truly means... or just drop it if it's not really needed. -- Cheers, Sakari Ailus e-mail: sakari.ailus@iki.fi XMPP: sailus@retiisi.org.uk